The story begins with Domenico Vandelli, the Paduan naturalist hired by the Portuguese crown in the 1760s to direct the Royal Botanical Garden and Royal Cabinet of Natural History at Ajuda in Lisbon. His unpublished 1779 instructions described gutting small mammals through an incision near the anus, replacing the viscera with camphor, and immersing the animal in diluted wine spirit with dissolved burnt alum. Birds were wrapped in cloth and bathed in spirit mixed with mercuric chloride, the toxic compound known as corrosive sublimate. Fishes, which ‘corrupt faster’, demanded stronger spirit and generous alum. Similar instructions issued in 1781 by the Royal Cabinet and the Academy of Sciences, largely the work of Vandelli and his student Alexandre Rodrigues Ferreira, refined these recipes and even specified how jars should be sealed with wax and resin.

These eighteenth-century prescriptions were not merely theoretical. A 1794 catalogue records that the Ajuda cabinet then held more than 1,100 fluid-preserved specimens, including human foetuses, ‘monstrous pigs’, hundreds of birds, snakes and fishes, many collected during Ferreira’s celebrated Philosophical Voyage to Brazil. Almost none survive. The rare exceptions are striking: the conjoined twins born in Évora in 1788 and preserved in wine spirit still exist in Lisbon’s Museu da Medicina, and a handful of ‘monsters’ described in Vandelli’s 1776 Dissertatio de monstris, along with several Brazilian reptiles collected by Ferreira, remain in the University of Coimbra’s collections.

The nineteenth century brought new manuals and new chemistry. In 1800, friar José Mariano da Conceição Velloso published a Portuguese adaptation of Abbé Manesse’s treatise, reporting experiments with solutions of alum, ammonia salt, nitre and sea salt, including a mixture that preserved a human foetus for over a year behind a simple cork stopper. In 1836, Francisco Assis de Carvalho, director of the newly reorganised National Museum in Lisbon, issued detailed taxon-by-taxon instructions specifying alcohol concentrations on the Baumé scale: skins at 14 to 18 degrees, whole reptiles at 20, venomous snakes at 20 to 24, fishes at 20 to 22. Notably, he recommended preserving venomous snakes intact precisely so that curators would not stab themselves on their fangs.

The most influential nineteenth-century text came from José Vicente Barbosa du Bocage, who took charge of the zoological section of the Lisbon Museum in 1858. His 1862 practical instructions circulated widely through the Portuguese empire and prescribed wine spirit at 20 to 22 degrees Baumé for fishes, reptiles, birds and small mammals, alongside alternative formulas combining salt, alum and corrosive sublimate, and a creosote solution of two grams per litre of water that, Bocage noted, avoided attacking colour or contracting soft tissues. Collectors such as José de Anchieta and Francisco Newton applied these methods across Angola, the Gulf of Guinea and Cape Verde, generating thousands of specimens. Many were lost in the catastrophic 1978 fire that destroyed the Museu Bocage, but duplicates distributed to other museums survive, including type specimens of Angolan mammals now in Porto and a rare specimen of the extinct Cape Verde giant-skink.

The 1890s marked a chemical revolution. In 1895, Adriano Xavier Lopes Vieira, director of the Zoology Museum at the University of Coimbra, argued that alcohol deformed and discoloured soft animals, was expensive and constantly evaporated, and proposed instead a four percent solution of formaldehyde. His colleague Manuel Paulino de Oliveira tested the new fixative that same year on anemones, crustaceans and salps, reporting that specimens died without retracting their appendages, retained their natural positions and colours, and hardened enough for histological study. Oliveira also documented the ’emzéd cement’, a hot mixture of paraffin and natural rubber applied to jar mouths with warmed glass lids, which he praised for sealing perfectly while still allowing jars to be reopened with a knife or hot water. That sealant, the study notes, appears to have worked remarkably well: many Coimbra jars from the period remain stable more than a century later.

King Carlos I of Portugal brought royal enthusiasm to the field. An active oceanographer who organised expeditions off the Portuguese coast in the late 1890s, he published a 1902 report detailing his own preservation protocols. Fishes were fixed in four percent formalin for about an hour, washed, and transferred to a ‘glycérine formolée’ mixture of glycerine, distilled water and formaldehyde that he credited with preserving colours indefinitely. Marine invertebrates were fixed in strong formalin and preserved in weak alcohol or the same glycerine solution. Many of the resulting specimens, including vividly coloured deep-sea crustaceans, are still extant at the Aquário Vasco da Gama in Cascais.

The twentieth century saw formalin and ethanol standardised. Instructions from the Sociedade de Geografia de Lisboa in 1912, Fernando Pedrosa Mendes’s 1942 museum manual with its tabulated anaesthetics, fixatives and preservatives for every invertebrate group, António de Barros Machado’s 1945 cave-biology formulas, and the detailed protocols of Fernando Frade’s colonial zoological missions all converged on seventy percent alcohol and five to ten percent formalin as the workhorses of preservation. The most comprehensive treatment came from marine biologist Luiz Saldanha, whose 1959, 1965 and 1972 publications laid out anaesthesia, fixation and preservation methods for taxa from sponges to fishes, complete with formula lists for Bouin’s fluid, Perenyi liquor, buffered formalin and colour-preserving alcohol-salt mixtures. Saldanha’s specimens were largely consumed by the 1978 fire, which the study describes as the single greatest loss to Portuguese fluid collections.

Why does this archival archaeology matter now? The authors emphasise that fixation history directly determines what modern science can do with a specimen. The quantity and quality of extractable DNA depend on the original fluids: formalin-fixed material, especially historical formalin, poses severe molecular challenges, while alcohol-preserved specimens are far more amenable. As museomics, the extraction of genomic data from historical collections, matures, knowing whether a jar’s contents were fixed in mercuric chloride-laced spirit, Goadby liquor or buffered formalin informs both the feasibility of sampling and the interpretation of results. The study also flags safety concerns, since corrosive sublimate, mercury and other toxic compounds lurk in legacy jars.

The paper closes with an account of recent recovery efforts at the Museu Nacional de História Natural e da Ciência in Lisbon, the Museu de História Natural e da Ciência in Porto and the Museu da Ciência in Coimbra: topping up evaporated fluids, transferring specimens to seventy percent ethanol, replacing cracked jars, printing resistant internal labels and digitising records for online databases. Yet the authors stress that understaffing remains the dominant threat, that no Portuguese degree programme teaches fluid preservation, and that curators must still decide whether these jars are scientific vouchers for the biodiversity crisis, historical relics of past science, or both. Mapping 250 years of recipes, they argue, is the essential first step toward answering that question.

Subject of Research: Historical fluid-preservation techniques used in Portuguese natural history collections from the eighteenth century to the 1970s and their implications for specimen management and research

Article Title: Fluid-preserved zoological specimens in Portuguese Natural History collections: a historical overview and implications to collection management and research

Article References: Ceríaco, L. M. P., & Marques, M. P. (2025). Fluid-preserved zoological specimens in Portuguese Natural History collections: a historical overview and implications to collection management and research. Natural History Collections and Museomics, 2, 1-69. https://doi.org/10.3897/nhcm.2.142114

Image Credits: AI Generated

DOI: 10.3897/nhcm.2.142114

Keywords: fluid preservation, natural history collections, museomics, formalin, ethanol, specimen fixation, Portugal, zoological collections, collection management, DNA extraction, museum conservation, history of science

Babesia species are single-celled parasites that invade red blood cells and are transmitted by ticks. In cattle, infections such as babesiosis cause fever, anemia, and significant economic losses, while in dogs the disease can be life-threatening. Human babesiosis, though less common, can be severe in elderly or immunocompromised patients. Because symptoms often overlap with other febrile illnesses, accurate molecular detection is essential—but conventional PCR-based diagnostics typically require laboratory infrastructure, thermal cyclers, and costly reagents that are out of reach in many field and rural settings.

The research team, led by Suphaporn Paenkaew and Kittisak Buddhachat at Naresuan University, set out to address one of the biggest bottlenecks in molecular diagnostics performed outside a laboratory: getting usable DNA out of a blood sample quickly and cheaply. The group evaluated five different blood DNA extraction approaches: a commercial DNeasy kit, simple boiling, TE buffer extraction, a methanol-based method, and Chelex 100 resin. Each extract was then fed into an RPA/CRISPR-Cas12a assay targeting the cytochrome c oxidase subunit I (COI) gene of Babesia.

Three of the five methods—the commercial kit, boiling, and TE buffer extraction—produced positive results in the CRISPR assay. The researchers then focused on the two simplest candidates, TE buffer extraction and boiling, and optimized the assay using Babesia-specific primers designed against the parasite’s 18S ribosomal RNA gene. When the performance of all extraction methods was compared head-to-head, they proved comparable to the commercial kit, but the TE buffer approach stood out for its simplicity and speed, requiring essentially no specialized equipment beyond a pipette and a source of the buffer itself.

The detection chemistry behind the assay is what makes the workflow so powerful. Recombinase polymerase amplification is an isothermal technique that copies DNA at a constant temperature—typically between body temperature and 42 degrees Celsius—without the cycling demanded by conventional PCR. In this study, the team optimized RPA conditions across a range from 25 to 45 degrees Celsius and incubation times from zero to 30 minutes, establishing conditions that work rapidly with minimal instrumentation. Once amplified, the target DNA triggers CRISPR–Cas12a, an enzyme that, upon binding its guide RNA-directed target sequence, unleashes indiscriminate cutting of nearby single-stranded DNA reporters, producing a detectable fluorescent signal.

Specificity is a critical concern for any diagnostic, and the assay passed that test. The RPA/CRISPR-Cas12a system specifically detected Babesia species including Babesia vogeli, Babesia gibsoni, and Babesia ovata—pathogens responsible for canine and bovine babesiosis in tropical and subtropical regions. The guide RNA was designed against a conserved region within the 18S rRNA gene amplification segment, with the protospacer adjacent motif and primer binding regions verified through multiple sequence alignments of Babesia sequences.

Sensitivity measurements revealed a trade-off worth noting. Using DNA extracted with TE buffer, the limit of detection was 10,000 copies per reaction, whereas the commercial kit achieved 1,000 copies per reaction—a tenfold difference in analytical sensitivity. The authors attribute this gap to the relative purity of kit-extracted DNA, which undergoes binding, washing, and elution steps that remove inhibitors. Even so, the TE-based workflow remained fully capable of detecting infections in clinical samples, suggesting that for field screening the modest sensitivity loss is an acceptable price for a dramatic reduction in cost and complexity.

The real-world validation came from clinical blood samples: seven bovine and eight canine specimens were tested using both the TE buffer extraction and the commercial kit, each followed by the RPA/CRISPR-Cas12a assay. The results showed complete concordance between the two extraction approaches, with six positive samples detected. The canine samples were additionally characterized by qPCR high-resolution melting analysis and conventional PCR with sequencing, confirming that the positives reflected genuine Babesia infections rather than assay artifacts.

The implications extend beyond veterinary clinics. The same research group has previously deployed RPA/CRISPR-Cas12a assays for other tick-borne pathogens, including Ehrlichia canis, Anaplasma platys, and Hepatozoon canis in dogs, and for Babesia vogeli specifically. Building a reliable, kit-free extraction step into that pipeline removes one of the last laboratory-dependent components. In regions where babesiosis is endemic and diagnostic laboratories are scarce, a workflow that needs only TE buffer, isothermal amplification reagents, and a CRISPR detection mix could be run in veterinary practices, farms, or mobile clinics.

The study, funded by the National Research Council of Thailand and Naresuan University, positions TE buffer extraction as a pragmatic bridge between sophisticated molecular diagnostics and the resource-limited settings that need them most. While the tenfold sensitivity gap relative to commercial kits may matter for very low-level infections, the complete agreement on clinical samples indicates that the simple method is fit for purpose. As CRISPR-based diagnostics continue to mature, studies like this one underscore that the humblest reagents—buffer, primers, and a guide RNA—can deliver laboratory-quality answers where they are needed fastest.

Subject of Research: A low-cost TE buffer DNA extraction method combined with RPA/CRISPR-Cas12a for rapid point-of-care detection of Babesia parasites

Article Title: A cost-effective and rapid TE-based DNA extraction for near point-of-care detection of Babesia spp. by RPA/CRISPR-Cas12a

Article References: Paenkaew, S., Sinthao, O., Thapthim, T., Mahakkaprateep, S., Cheukaw, A., Keawmanee, S., Euppayo, T., Tungtrakanpoung, R., Teapunvong, W., Nganvongpanit, K., & Buddhachat, K. (2026). A cost-effective and rapid TE-based DNA extraction for near point-of-care detection of Babesia spp. by RPA/CRISPR-Cas12a. Molecular Biology Reports, 53(1), Article 1545. https://doi.org/10.1007/s11033-026-12665-2

Image Credits: AI Generated

DOI: 10.1007/s11033-026-12665-2

Keywords: Babesia, DNA extraction, TE buffer, CRISPR-Cas12a, recombinase polymerase amplification, point-of-care diagnostics, babesiosis, 18S rRNA, veterinary parasitology, tick-borne disease, molecular detection, isothermal amplification

An international team working under the eWHALE project, a collaborative initiative spanning the North-East Atlantic and the Mediterranean Sea, set out to answer a deceptively simple question: if four laboratories extract DNA from the very same water samples, do they get the same results? The answer, revealed through a rigorous inter-laboratory comparison known as a ring test, was not always. Despite similar total DNA concentrations across all participating facilities, one laboratory’s extraction protocol performed significantly worse at detecting the target species, and the discrepancy was only caught because the partners had agreed to test themselves against each other before the real monitoring work began.

The ring test involved four institutions: the University of Innsbruck in Austria, INRAE in France, University College Cork in Ireland, and the Institute of Marine Research in Norway. In summer 2023, each partner contributed water samples collected near marine megafauna in their home waters. Innsbruck supplied samples gathered near sperm whales in the Mediterranean and around the Azores, INRAE contributed samples taken near porbeagle sharks off Brittany, Cork collected water in the Shannon Estuary where bottlenose dolphins surface in groups, and the Norwegian institute sampled near basking sharks by the Lofoten Islands. In total, 39 eDNA samples entered the comparison.

The experimental design was elegant in its simplicity. Each laboratory first lysed its own filters, breaking open cells and releasing DNA into a storage buffer. Then, 250-microliter aliquots of every lysate were shipped to all four partners, where each facility extracted DNA using its own preferred protocol. The extracts were shipped back to the laboratory of origin for analysis. This exchange meant that every original sample could be measured four times over, once per extraction method, allowing researchers to isolate the effect of the extraction chemistry itself from the noise of field sampling.

The extraction methods themselves reflected the everyday reality of eDNA research. Innsbruck used a Qiagen BioSprint 96 Workstation, an automated platform that relies on paramagnetic beads to capture DNA. INRAE employed a Macherey-Nagel NucleoSpin Tissue Kit with repeated heated elutions, while Cork and the Norwegian institute both used the widely recommended Qiagen DNeasy Blood and Tissue Kit, albeit with different modifications, including vacuum-assisted filtration in Norway and an extended 56-degree incubation of lysates in Ireland. Each of these small choices, the study found, could ripple forward into the final检测结果, though the differences were often invisible when measuring total DNA alone.

To evaluate detection performance, the team developed three novel species-specific quantitative PCR assays, one each for sperm whale, porbeagle shark, and basking shark, using mitochondrial genes and a software pipeline called assayID that ranks candidate primer and probe designs by specificity and sensitivity. These TaqMan assays, alongside an existing SYBR Green assay for dolphin DNA developed at Cork, were validated in silico, in vitro, and finally against field samples, reaching Level 3 of the widely accepted five-level validation framework proposed by Thalinger and colleagues. The assays proved remarkably sensitive, with limits of detection as low as 0.00001 nanograms per microliter for dolphins, but sensitivity alone could not rescue poor extracts.

The statistical verdict was clear. Across 468 qPCR reactions, 115 amplified their target species. Total DNA concentrations measured by Qubit fluorometer did not differ significantly between laboratories, yet detection probability did. Extracts produced by the Norwegian laboratory amplified target species DNA significantly less often than those from the other three partners, in both an all-inclusive dataset and a conservative dataset restricted to amplifications at or above each assay’s limit of detection. When the team examined the protocols side by side, two subtle differences emerged between the Norwegian and Irish workflows, which otherwise used nearly identical kits: the extra hour of lysate incubation in Ireland may have improved DNA binding to silica membranes, while the vacuum system used in Norway may have compromised binding efficiency or left residual ethanol in the extracts.

Species identity mattered as much as laboratory identity. Sperm whale DNA was detected in 43 reactions and dolphin DNA in 56, while porbeagle shark yielded only 13 detections and basking shark a mere three, all vanishing entirely from the conservative dataset. The researchers attribute this pattern partly to biology: marine mammals slough skin and defecate at the surface between feeding dives, seeding the water with DNA, whereas sharks shed far less genetic material. Sampling design compounded the problem, as sperm whale samples were drawn from 10-liter volumes while shark samples came from only 5 liters, and some basking shark samples were likely collected too far from the animals themselves. A significant interaction between laboratory and species further suggested that extraction efficiency depends on the environmental character of each sample, meaning no single protocol is universally superior.

The study also offers a cautionary lesson about the limits of detection. Nearly 80 percent of the positive amplifications fell below the assays’ formal limits of detection, and excluding those low-level signals reduced overall detection rates by roughly 20 percent. Interpreting such borderline amplifications requires care, the authors argue, because treating them as false positives risks discarding real detections of genuinely rare species, while trusting them uncritically invites statistical noise. For cross-laboratory comparisons in particular, the conservative approach provides the fairest benchmark, since DNA extracted from the same environmental sample should theoretically be identical regardless of who processed it.

The practical outcome of the ring test was immediate: the Norwegian laboratory modified its extraction protocol for the remainder of the project, and the eWHALE partners now possess a documented, quantified understanding of how their methods compare. Three newly published qPCR assays are available for other eDNA practitioners targeting sperm whale, porbeagle shark, and basking shark. More broadly, the study stands as a template for what multinational eDNA monitoring should look like from the start, with validation exercises built in before any ecological conclusions are drawn. As eDNA moves from an academic curiosity toward routine conservation decision-making, the authors argue, this kind of inter-laboratory rigor is not optional overhead but the very foundation upon which comparable, trustworthy biodiversity data must rest.

Subject of Research: Inter-laboratory comparison of environmental DNA extraction protocols for detecting marine megafauna using novel species-specific qPCR assays

Article Title: Inter-laboratory ring test for environmental DNA extraction protocols: implications for marine megafauna detection using three novel qPCR assays

Article References: Rodriguez, L. K., De Bonis, L., McKee, J., McKenna, J. A., Urvois, T., Barbaccia, E., Dillane, E., Lanfredi, C., Hjellnes, H., Jung, A., Villa, E., Azzellino, A., Westgaard, J.-I., Quéméré, E., & Thalinger, B. (2025). Inter-laboratory ring test for environmental DNA extraction protocols: implications for marine megafauna detection using three novel qPCR assays. Metabarcoding and Metagenomics, 9, Article e128235. https://doi.org/10.3897/mbmg.9.128235

Image Credits: AI Generated

DOI: 10.3897/mbmg.9.128235

Keywords: environmental DNA, eDNA, ring test, marine megafauna, qPCR, sperm whale, porbeagle shark, basking shark, dolphins, DNA extraction, laboratory standardization, eWHALE project

A new study published in the journal Metabarcoding and Metagenomics tackles this problem head-on with one of the most ambitious interlaboratory exercises yet attempted for diatom metabarcoding. Under the coordination of a reference laboratory, 17 participants from 14 countries carried out DNA extraction and PCR amplification in parallel on a shared set of standardised samples, following both a fixed common protocol and their own preferred in-house methods. The goal was to measure precisely where variability creeps into the workflow and whether the ecological conclusions drawn from the data survive the journey between laboratories.

The stakes are higher than they might appear. Environmental legislation across Europe, including the Water Framework Directive, requires member states to classify the ecological status of water bodies using consistent methods. If one country’s DNA-based diatom index systematically produces different scores than another’s, regulators cannot pool results, benchmark progress or trust cross-border comparisons. The research team, led by Valentin Vasselon and colleagues, therefore designed their proficiency test around the two steps of the metabarcoding pipeline that are most notorious for introducing laboratory-specific bias: extracting DNA from biofilm samples and amplifying target genetic markers with the polymerase chain reaction.

Participants received an identical package of test materials, including DNA extracts and biofilm samples collected from rivers and lakes, together with an artificial mock community of known diatom composition. The mock community served as a critical control: because its true composition was known in advance, any deviation in the sequencing results could be traced directly to errors introduced during laboratory processing rather than to genuine ecological differences between samples. Each laboratory performed the work under both conditions, first adhering strictly to a prescribed reference protocol and then applying whatever extraction kit and PCR setup they would normally use in routine monitoring.

The central finding is strikingly positive. When laboratories followed the shared protocol, their results proved highly reproducible, demonstrating that the method can be transferred successfully between facilities in different countries without specialised equipment or bespoke reagents. Even more reassuring for the future of routine monitoring, the ecological assessment outcomes remained highly similar and consistent regardless of which protocol each participant chose to apply. In practical terms, this means that the biological quality scores derived from diatom metabarcoding were robust to the reasonable diversity of laboratory practices currently in use across the scientific community.

That robustness matters because the alternative, forcing every laboratory onto a single rigid protocol, would be both politically and practically difficult. Different countries have invested in different extraction chemistries, primer sets and sequencing platforms over years of method development, and a blanket mandate would discard that accumulated expertise. The study’s authors instead propose a strategy they describe as all for one but prove them all: laboratories may continue using their preferred protocols, provided each one demonstrates its consistency by meeting minimum standard requirements verified through proficiency testing. This reframes standardisation not as uniformity of method but as uniformity of demonstrated performance.

The experimental design also illuminated the specific sources of variability that future standardisation efforts must control. By comparing results across the paired experiments, the team could separate systematic errors, which bias results in a consistent direction, from random errors, which add noise unpredictably. The inclusion of river, lake and mock community samples allowed them to test whether certain sample types or taxonomic compositions were more vulnerable to laboratory effects than others. Such distinctions are essential for deciding which steps of the workflow genuinely need harmonisation and which can safely be left to local preference.

The study arrives at a moment when DNA-based biomonitoring is transitioning from research demonstration to regulatory deployment. National programmes in several European countries have already shown that diatom metabarcoding can reproduce the ecological classifications traditionally obtained by microscopic identification, and in some cases the genetic approach detects additional species and provides finer resolution. What has been missing is the layer of quality assurance that mature analytical disciplines take for granted: ring trials, certified reference materials and documented evidence that a result from one accredited laboratory means the same thing as a result from another. This proficiency test provides a template for building exactly that layer.

The collaborative scale of the exercise is itself noteworthy. Seventeen laboratories spanning 14 countries, from established national reference facilities to smaller academic groups, executed identical experimental workflows in parallel, generating a dataset rich enough to disentangle protocol effects from laboratory effects and sample effects. The author list reflects a genuinely pan-European network of diatom ecologists, molecular biologists and water managers, suggesting that the community has reached the critical mass needed to sustain long-term intercalibration exercises of this kind.

For water managers and regulators, the practical message is that diatom DNA metabarcoding is now technically ready for routine application, provided that laboratories participate in ongoing proficiency testing and demonstrate that their chosen protocols meet agreed minimum standards. For the research community, the study offers a roadmap: standardised sample sets, mock communities as benchmarks, paired protocol comparisons and a reference laboratory to anchor the exercise. If future rounds of testing confirm these findings across more laboratories and more diverse freshwater types, the microscopic algae that have quietly recorded the health of Europe’s rivers for over a century may soon have their status read not through a microscope lens but through the language of DNA, with results that laboratories across the continent can finally compare on equal terms.

Subject of Research: Cross-laboratory proficiency testing to standardise diatom DNA metabarcoding for freshwater biomonitoring

Article Title: Proficiency testing and cross-laboratory method comparison to support standardisation of diatom DNA metabarcoding for freshwater biomonitoring

Article References: Vasselon, V., Rivera, S. F., Ács, É., Almeida, S. F. P., Andree, K. B., Apothéloz-Perret-Gentil, L., Bailet, B., Baričević, A., Beentjes, K. K., Bettig, J., Bouchez, A., Capelli, C., Chardon, C., Duleba, M., Elersek, T., Genthon, C., Jablonska, M., Jacas, L., Kahlert, M., … Paix, B. (2025). Proficiency testing and cross-laboratory method comparison to support standardisation of diatom DNA metabarcoding for freshwater biomonitoring. Metabarcoding and Metagenomics, 9, Article e133264. https://doi.org/10.3897/mbmg.9.133264

Image Credits: AI Generated

DOI: 10.3897/mbmg.9.133264

Keywords: diatoms, DNA metabarcoding, biomonitoring, freshwater, proficiency testing, standardisation, PCR amplification, DNA extraction, water quality, ecological assessment, interlaboratory comparison, mock community

The study focused on stemflow, the water that runs down tree trunks, as a source of environmental DNA for arboreal biodiversity. Stemflow sampling captures biological material from the tree canopy and bark, providing a snapshot of the organisms associated with the tree. The researchers collected stemflow from a Japanese apricot tree in Aoba-no-Mori Park, Chiba City, Japan, during a rainy day in July 2023. This method allows for the passive collection of DNA shed by lichens, fungi, and other microorganisms living on the tree surface, offering a comprehensive view of the local biological community without the need for direct physical sampling of the organisms themselves.

To evaluate the impact of sample preparation, the team compared three distinct DNA extraction methods. The first method involved no homogenization, where lichen fragments trapped on filters were processed directly. The second method utilized bead-beating, a technique where zirconia beads are vortexed with the sample to mechanically break open cell walls. The third method combined bead-beating with freezing, where samples were soaked in liquid nitrogen before mechanical disruption. By comparing these approaches, the researchers aimed to determine whether the additional step of freezing provided any significant advantage over standard bead-beating in terms of DNA yield and species detection.

The results clearly indicated that homogenization plays a pivotal role in the success of eDNA metabarcoding for lichens. Samples processed without homogenization detected the fewest species, with an average of only 4.2 species per sample. In contrast, both bead-beating and frozen bead-beating methods detected significantly more species, with averages of 8.0 and 7.8 species per sample, respectively. Statistical analysis confirmed that the difference between the non-homogenized samples and the homogenized samples was significant, while no significant difference was observed between the two homogenization methods. This suggests that the mechanical action of bead-beating is the primary driver of improved DNA recovery.

Quantitative real-time PCR assays further supported these findings by measuring the concentration of extracted DNA. The non-homogenized samples yielded the lowest DNA concentrations, averaging 7.2 picograms per 2 microliters. Conversely, the bead-beating and frozen bead-beating samples produced substantially higher yields, averaging 53.5 and 53.1 picograms per 2 microliters, respectively. A strong positive correlation was observed between DNA concentration and the number of detected species, with a coefficient of determination of 0.707. This relationship underscores the importance of maximizing DNA extraction efficiency to ensure that rare or low-abundance species are not missed during sequencing.

The study also examined the consistency of species detection across different samples. The non-homogenized samples exhibited high dissimilarity in species composition, with an average Jaccard distance of 0.493. This variability is likely due to the low template DNA concentrations, which can lead to stochastic effects during PCR amplification. In contrast, the homogenized samples showed much lower dissimilarity, with averages ranging from 0.1 to 0.2. This consistency indicates that bead-beating not only increases the total amount of DNA but also stabilizes the detection of species, reducing the random fluctuations that can occur when working with low-concentration templates.

When comparing eDNA results with visual observations of lichens on the tree, the study found that metabarcoding successfully identified most of the visually observed foliose lichen species. However, detection rates varied depending on the extraction method. For instance, two common species, Parmotrema austrosinense and P. tinctorum, were detected more frequently in the homogenized samples than in the non-homogenized ones. The absence of some species, such as Flavoparmelia caperata, across all methods may be attributed to factors like DNA degradation or primer mismatches. Nevertheless, the eDNA approach also detected several non-target taxa, including additional foliose and crustose lichens, highlighting its potential to reveal hidden biodiversity that might be overlooked by visual surveys alone.

The researchers noted that the choice of reference database is crucial for accurate taxonomic assignment. In this study, a curated database of ITS sequences from known lichen species was used to minimize the risk of erroneous classifications. While the database was smaller than those typically used in large-scale eDNA studies, it was deemed sufficient for the specific context of the research, which focused on a single tree with a known set of lichen species. The use of a targeted reference library helped ensure that the taxonomic assignments were reliable, even in the presence of low-abundance sequences.

Despite the clear benefits of bead-beating, the study acknowledges several limitations. The research was conducted on a single tree, which limits the generalizability of the findings to other species or environments. Additionally, the low DNA concentrations in the samples made the PCR amplification process sensitive to random fluctuations and potential contamination. The researchers also noted that the intensity of bead-beating can influence microbial community composition, and further studies are needed to determine the optimal parameters for different types of organisms. These considerations highlight the need for standardized protocols in eDNA metabarcoding to ensure comparability across different studies and ecological contexts.

In conclusion, the study provides valuable insights into the optimization of eDNA metabarcoding for lichen biodiversity monitoring. The findings suggest that bead-beating is an effective and efficient pre-treatment for extracting lichen DNA from environmental samples, significantly improving both DNA yield and species detection. The additional step of freezing before bead-beating did not offer any significant advantage, making standard bead-beating the most cost-effective and practical option. As eDNA techniques continue to evolve, refining laboratory protocols like homogenization will be essential for unlocking the full potential of this powerful tool in biodiversity assessment and conservation efforts.

Subject of Research: Optimization of environmental DNA extraction methods for lichen biodiversity monitoring

Article Title: Influence of homogenization methods on lichen species detection from environmental DNA metabarcoding

Article References: Sakata, A., Minamoto, T., Sado, T., Gotoh, R. O., & Miya, M. (2025). Influence of homogenization methods on lichen species detection from environmental DNA metabarcoding. Metabarcoding and Metagenomics, 9, Article e144340. https://doi.org/10.3897/mbmg.9.144340

Image Credits: AI Generated

DOI: 10.3897/mbmg.9.144340

Keywords: environmental DNA, metabarcoding, lichens, biodiversity monitoring, DNA extraction, bead-beating, stemflow, qPCR, taxonomic assignment, ecology, Influence, homogenization

The research team, working with samples collected during the 2018 MANGAN expedition aboard the RV Sonne, compared two fundamentally different DNA extraction strategies for assessing benthic metazoan diversity. The first, called community DNA (ComDNA), involves physically isolating the tiny animals—meiofauna—from the sediment before extracting their DNA. The second, sedimentary environmental DNA (SedDNA), extracts DNA directly from whole sediment samples. Both approaches were applied to sediment cores collected from 19 stations in the eastern part of the BGR contract area, at water depths of roughly 4,000 to 4,100 meters.

The results were striking. ComDNA extractions yielded 2,145 metazoan operational taxonomic units (OTUs), while SedDNA recovered only 392 OTUs from the same cores. Even more remarkable, only 1.2 percent of OTUs were shared between the two methods. Of the 2,507 total OTUs detected across both strategies, 2,115 were unique to ComDNA and 362 were unique to SedDNA. This means the two approaches are not simply capturing the same community with different efficiency—they are detecting substantially different subsets of the fauna.

The statistical analyses reinforced this picture. Non-metric multidimensional scaling based on both Bray–Curtis and Jaccard distances revealed two distinct, non-overlapping benthic communities corresponding to the two extraction strategies. A pairwise PERMANOVA confirmed that extraction method had a highly significant effect on community composition (p < 0.001), while sampling location did not. OTU richness was significantly greater in the ComDNA dataset (p < 0.01), and Shannon diversity followed the same pattern (p < 0.05).

Taxonomically, both methods detected Annelida as the dominant phylum by relative read abundance—50.5 percent in ComDNA and 58.8 percent in SedDNA. However, the composition beneath that headline differed. In ComDNA, Nematoda accounted for 23.2 percent of reads, followed by Arthropoda (14.3 percent) and Nemertea (6.5 percent). In SedDNA, Arthropoda came second (19.5 percent) and Nematoda third (6.7 percent). Four phyla—Hemichordata, Loricifera, Chaetognatha and Entoprocta—were detected exclusively in ComDNA samples, likely because their small, free-swimming larval stages or soft bodies are captured by the organismal enrichment process but missed by direct sediment extraction.

The underlying reason for the gap is partly technical. ComDNA extraction concentrates the target organisms through sieving and centrifugation, reducing non-target DNA and PCR inhibitors while improving DNA yield and quality. In the ComDNA dataset, 6.29 percent of high-quality reads were assigned to metazoans, representing 75.7 percent of OTUs. In the SedDNA dataset, only 1.27 percent of reads and 25.9 percent of OTUs were metazoan. The rest of the signal came from fungi and diverse microeukaryotes, which swamp the metazoan signal when DNA is extracted from raw sediment.

Recognizing that SedDNA is far more practical for large-scale monitoring—it requires no onboard sieving, reduces contamination risk, and allows many more samples to be processed—the researchers modeled how much sediment would need to be processed to match the OTU richness achieved by ComDNA. Using random subsampling of sample combinations and fitting both linear and Michaelis–Menten models, they estimated that between 27 and 82 milliliters of sediment would be required, depending on sequencing depth and statistical approach. By comparison, the ComDNA protocol processed 217 milliliters of sediment per sample. At a sequencing depth of 100,000 reads per sample, the Michaelis–Menten model suggested approximately 38.8 milliliters would suffice.

The study also highlights the importance of sediment homogenization. Deep-sea benthic communities exhibit pronounced spatial heterogeneity, even at microhabitat scales, and meiofauna often cluster in patches rich in organic matter. Homogenizing the entire sediment volume before subsampling would help ensure that the DNA extract reflects the underlying community rather than a localized hotspot. However, this comes with a trade-off: homogenization eliminates vertical stratification, obscuring depth-dependent patterns in community structure. The authors recommend homogenizing each sediment layer separately if vertical resolution is needed.

For environmental impact assessments ahead of deep-sea mining, the message is clear. ComDNA extraction remains the more reliable strategy for establishing high-resolution biodiversity baselines, despite its greater cost and labor. SedDNA approaches, with optimized protocols—larger sample volumes, homogenization, and sequencing depths of at least 100,000 reads per sample—hold promise for scalable monitoring programs, particularly where rapid, broad-scale surveys are needed. The authors also call for further methodological research, including the evaluation of technical PCR replicates and standardized sediment processing protocols, to refine sediment-based eDNA approaches before they can be trusted for regulatory decisions in one of the planet’s last unexplored frontiers.

Subject of Research: Comparison of community DNA and sedimentary eDNA metabarcoding for deep-sea benthic biodiversity assessment

Article Title: Community DNA outperforms eDNA metabarcoding for biodiversity assessments in the Clarion–Clipperton Fracture Zone

Article References: Damm, L., Khodami, S., Rubel, V., Molari, M., Vink, A., Stoeck, T., & Martinez Arbizu, P. (2026). Community DNA outperforms eDNA metabarcoding for biodiversity assessments in the Clarion–Clipperton Fracture Zone. Metabarcoding and Metagenomics, 10, Article e173793. https://doi.org/10.3897/mbmg.10.173793

Image Credits: AI Generated

DOI: 10.3897/mbmg.10.173793

Keywords: eDNA metabarcoding, community DNA, Clarion–Clipperton Fracture Zone, deep-sea mining, meiofauna, benthic biodiversity, polymetallic nodules, environmental DNA, DNA extraction, 18S rRNA, deep-sea monitoring, environmental impact assessment

The research team, working with seawater collected aboard the research vessel Miguel Oliver during the PELACUS 0324 survey, sampled three stations off the northwest Iberian Peninsula: Northern Galicia, Costa da Morte, and the Ria de Arousa. At each site, they filtered eight liters of seawater through Sterivex cartridge filters and then split the material between two extraction strategies. The first was the standard DNeasy PowerWater Sterivex protocol, a widely used commercial kit designed specifically for enclosed filters. The second added a preliminary bead-beating homogenization step, in which the filter membrane was removed from its cartridge, cut into fragments, and physically shattered with metal beads before following the standard protocol, on the theory that breaking open more cells would release more DNA.

The result was a clear win for simplicity. The standard, hands-off protocol yielded DNA concentrations roughly six to seventeen times higher than the bead-beating variant across the three stations, and it also recovered slightly more amplicon sequence variants, the fine-grained genetic units used to measure biodiversity. Both methods captured a broadly similar cast of marine vertebrates, including sardines, anchovies, sea bream, and even a fin whale at one station, but the extra handling involved in the modified method appears to have cost more than it gained, likely through DNA loss and increased contamination risk when the filter was manipulated outside its sealed unit.

One of the more intriguing questions the study addressed concerns free extracellular DNA, or f-exDNA: genetic material floating loose in seawater, not attached to cells or particles. Some researchers have suggested this fraction could pass straight through filter membranes and be lost. Using controlled seawater samples spiked with common dolphin DNA at known concentrations, the team found that recovery of this free DNA remained low with both extraction methods, generally below one percent, and actually declined as DNA concentrations rose, possibly because binding sites on the filter membrane became saturated. The finding suggests that particle-associated DNA, rather than free-floating strands, is what filters and extraction kits are mostly capturing, though the authors caution that more work is needed to disentangle the different DNA subfractions in natural waters.

The next variable under scrutiny was the polymerase enzyme, the molecular workhorse that copies target DNA during PCR. The team compared a high-fidelity proofreading polymerase, Platinum SuperFi II, which corrects its own replication errors using exonuclease activity, with a cheaper non-proofreading enzyme, Supreme NZYTaq. There is a technical wrinkle here: the same exonuclease activity that makes proofreading enzymes accurate can also chew back mismatches at the ends of primers, potentially altering which taxa amplify successfully. Using artificial mock communities containing DNA from sixteen vertebrate species at equal concentrations, the researchers ran paired statistical tests on the read outputs of both enzymes.

The verdict was taxon-dependent and, in a way, counterintuitive. The proofreading enzyme generated significantly more reads from fish, amplifying bony fish DNA more effectively, while the non-proofreading enzyme produced significantly more cetacean reads, although that effect was weaker and more variable. Both enzymes detected all sixteen species in the mock communities, meaning the cheaper enzyme did not miss anything. In real environmental samples, the picture was messier: the two enzymes produced overlapping but distinct species lists, with seven species shared, six detected only with the proofreading enzyme, and four only with the non-proofreading one, a discrepancy the authors attribute to the inherent stochasticity of the metabarcoding workflow rather than to enzyme choice alone.

For practical purposes, the message is that budget-conscious monitoring programs may not need the expensive high-fidelity option. The non-proofreading enzyme delivered comparable overall species detection in environmental samples and excelled at cetacean detection, making it a cost-effective choice when the goal is tracking marine mammals. The authors do note that polymerases can introduce sequence-composition biases related to guanine-cytosine content, which may distort relative abundance estimates even when presence or absence data remain reliable, so abundance-based ecological interpretations still warrant caution.

The third pillar of the study is MVeM, the Marine Vertebrate eDNA Metabarcoding bioinformatics pipeline, an open-source, adaptable workflow now available on GitHub. After raw reads are trimmed and processed with the DADA2 algorithm to infer sequence variants, taxonomic assignment proceeds through BLAST searches against the NCBI nucleotide database with stringent filters: at least ninety-nine percent sequence identity, sufficient alignment length, and exclusion of generic environmental sample entries so that every assignment traces back to vouchered tissue specimens. The pipeline then layers on several safeguards against false positives.

Among those safeguards are a customizable geographic ban list that automatically screens out species implausible for the study region, a filter against nuclear mitochondrial DNA segments, or NUMTs, which are mitochondrial fragments lurking in the nuclear genome that can masquerade as genuine detections, and a Lowest Common Ancestor fallback that assigns ambiguous matches to a genus or family rather than gambling on a species call. Contamination control is handled with an unusual touch of machine learning: instead of a fixed read threshold, an unsupervised classification method flags potential contaminants sample by sample, accounting for variable sequencing depth while still preserving genuinely abundant biological signals that might appear as faint traces in control blanks.

Importantly, the authors are candid that their environmental comparisons rest on limited replication, so the extraction and enzyme trends should be read as exploratory rather than statistically definitive. Even so, the study lands at a moment when eDNA is moving from research curiosity to policy tool, feeding into fisheries assessments and conservation planning. By showing that a simple, minimally invasive extraction, a thoughtfully chosen polymerase, and a rigorous, transparent bioinformatics framework can together deliver reliable marine vertebrate inventories, the work offers exactly what the field has been asking for: a standardized, accessible recipe for reading the ocean’s genetic fingerprint, one water sample at a time.

Subject of Research: Optimization of environmental DNA metabarcoding methods for monitoring marine vertebrate biodiversity

Article Title: Evaluating eDNA metabarcoding methods for marine vertebrate monitoring

Article References: Afonso, L., Álvarez-González, M., Pascoal, F., Sánchez-Barreiro, F., Rojo, V., Saavedra, C., Costa, J., Covelo, P., Pierce, G. J., Correia, A. M., Magalhães, C., & Suarez-Bregua, P. (2026). Evaluating eDNA metabarcoding methods for marine vertebrate monitoring. Metabarcoding and Metagenomics, 10, Article e191426. https://doi.org/10.3897/mbmg.10.191426

Image Credits: AI Generated

DOI: 10.3897/mbmg.10.191426

Keywords: environmental DNA, eDNA metabarcoding, marine vertebrates, biodiversity monitoring, DNA extraction, polymerase, bioinformatics pipeline, MVeM, Sterivex filters, cetaceans, contamination control, marine conservation

The challenge the researchers set out to address is familiar to every elimination program. As transmission falls, infected individuals increasingly carry very small numbers of parasites in their blood, often below the threshold that a microscopist examining a blood smear can reliably detect. These submicroscopic infections still contribute to onward transmission, because mosquitoes that feed on an infected person can pick up gametocytes even when the density of parasites in the peripheral blood is tiny. In settings such as the Amazon basin, where P. vivax in particular hides in the liver and re-emerges in relapses, missing these infections allows reservoirs of disease to persist in communities that appear, on paper, to be approaching elimination.

Loop-mediated isothermal amplification was developed as a molecular diagnostic that avoids the thermal cycling equipment required by conventional PCR. Instead of repeatedly heating and cooling a sample, LAMP uses a strand-displacing DNA polymerase and four to six specially designed primers that recognize six to eight distinct regions of the target genome. The reaction proceeds at a constant temperature, typically around 60 to 65 degrees Celsius, which can be maintained by a simple heating block or even a water bath. Amplification produces enormous quantities of pyrophosphate and protons as byproducts, and in a colorimetric formulation a pH-sensitive dye shifts color when the reaction succeeds, turning a positive result into something a technician can read with the naked eye.

That simplicity is what makes cLAMP attractive for field surveillance, but the technology has a well-known Achilles heel: sample preparation. DNA extraction remains the most technically demanding and contamination-prone step in any molecular assay, and the choice of extraction method can dominate overall performance. The Peruvian team confronted this directly by comparing two approaches on the same samples. The first was a mini spin column method, in which DNA is bound to a silica membrane, washed, and eluted in clean buffer, a process that concentrates and purifies genetic material but requires more reagents, equipment, and hands-on time. The second was a boil-and-spin method, in which a small piece of dried blood is simply heated in water or buffer to release DNA, then briefly centrifuged to pellet debris, leaving crude lysate ready for amplification.

The samples came from two complementary surveillance strategies that elimination programs run in parallel. Active case detection, abbreviated ACD, involves health workers visiting communities and screening people regardless of whether they feel ill, in order to flush out asymptomatic carriers. Passive case detection, or PCD, relies on patients who come to a clinic with fever or other symptoms. The study analyzed 574 dried blood spots from active detection and 431 from passive detection. Dried blood spots themselves are a surveillance workhorse: a finger-prick of blood spotted onto filter paper, dried, and stored, they are cheap to collect, stable at ambient temperatures for weeks to months, and far easier to transport from remote river communities to a laboratory than whole blood or slides.

To judge how well cLAMP performed, the researchers benchmarked it against two references. Real-time quantitative PCR, or qPCR, served as the molecular gold standard, while microscopy represented the current reality of most field diagnosis. The gap between the two was stark. In the active detection set, qPCR identified 125 positive samples, 117 of them P. vivax and 8 P. falciparum. Microscopy, run against that standard, achieved a sensitivity of only 57.6 percent, meaning it missed more than four in ten infections that were genuinely present. cLAMP with the crude boil-and-spin extraction did somewhat better, reaching 63.2 percent sensitivity, while cLAMP paired with the spin column extraction climbed to 82.4 percent, a dramatic improvement over the smear.

The passive detection samples told a related but distinct story. Here qPCR found 140 positives, comprising 129 P. vivax infections, 9 P. falciparum infections, and 2 mixed infections containing both species. Because symptomatic patients generally carry higher parasite densities, microscopy fared better in this group, achieving 72.9 percent sensitivity. cLAMP with boil-and-spin extraction reached 77.1 percent, roughly comparable to the smear, while the column-based extraction again pushed sensitivity to 82.1 percent. Across both surveillance modes and all diagnostic methods, specificity remained above 99 percent, indicating that false positives were vanishingly rare and that a positive result could be trusted as a true infection.

The pattern in these numbers carries a clear technical message. The amplification chemistry itself is sensitive enough, but its real-world performance is gated by the quality of the DNA template fed into it. Boil-and-spin extraction releases parasite DNA but also carries blood-derived inhibitors and leaves the template dilute, which hurts most precisely where sensitivity matters most: in the low-density, often asymptomatic infections found by active case detection. Column-based extraction cleans and concentrates the template, and the benefit shows up disproportionately in the ACD samples, where cLAMP with columns outperformed microscopy by nearly 25 percentage points. In passive surveillance, where parasite densities run higher, the extraction method mattered less because even crude lysate contained enough template for the reaction to succeed.

For program managers weighing options in low-transmission settings, the study frames a trade-off rather than a single verdict. Boil-and-spin cLAMP is cheaper, faster, and simpler, and it performs at least as well as microscopy, making it a plausible upgrade for laboratories that cannot sustain column-based workflows. Column-based cLAMP, meanwhile, delivers sensitivity approaching qPCR from a filter paper sample, without needing a thermocycler or fluorescent detection hardware, and it substantially outperforms the smear in exactly the active surveillance campaigns where finding hidden infections is the whole point. Because the readout is a visible color change, results do not require expensive instruments, and the isothermal reaction can run on basic laboratory equipment already common in regional health posts.

The authors conclude that cLAMP, particularly when combined with column-based DNA extraction, is a practical and sensitive complementary tool for malaria surveillance in elimination settings. As countries in the Amazon and beyond push toward the last mile of malaria elimination, the infections that matter are the ones nobody can see under a microscope, and tools that can find them cheaply, reliably, and close to the communities where they occur will determine whether the final stretch of the campaign succeeds. This study suggests that a color-changing tube, a filter paper spot, and a careful choice of extraction chemistry may be enough to bring molecular-grade detection out of the reference laboratory and into the field.

Subject of Research: Evaluation of colorimetric loop-mediated isothermal amplification for malaria detection from dried blood spots in the Peruvian Amazon

Article Title: Detection of Plasmodium vivax and Plasmodium falciparum using colorimetric loop-mediated isothermal amplification from dried blood spots collected in active and passive malaria surveillance in the Peruvian Amazon

Article References: Nolasco, O., Gómez, J., Rodríguez-Ferrucci, H., Gamboa, D., & Delgado-Ratto, C. (2026). Detection of Plasmodium vivax and Plasmodium falciparum using colorimetric loop-mediated isothermal amplification from dried blood spots collected in active and passive malaria surveillance in the Peruvian Amazon. PLOS Neglected Tropical Diseases, 20(10), e0014366. https://doi.org/10.1371/journal.pntd.0014366

Image Credits: AI Generated

DOI: 10.1371/journal.pntd.0014366

Keywords: malaria, Plasmodium vivax, Plasmodium falciparum, LAMP, colorimetric assay, dried blood spots, molecular diagnostics, active case detection, passive case detection, Peruvian Amazon, malaria elimination, DNA extraction

The research, led by Carla Teixeira of the International Iberian Nanotechnology Laboratory in Braga, Portugal, together with colleagues at the University of Santiago de Compostela in Spain, the University of Minho, and FOCOS GmbH in Germany, focuses on the often overlooked first step of any DNA-based diagnostic: getting clean, amplifiable DNA out of a complicated food matrix. The team built a prototype device that uses controlled pore glass as the solid phase onto which DNA binds and from which it is later released, and they paired it with a protocol that avoids chaotropic salts, the harsh chemicals that most conventional extraction chemistries rely on to disrupt proteins and free nucleic acids from their surroundings.

DNA has become an increasingly favored target for allergen detection because of a combination of properties that protein-based methods struggle to match. Genetic material is thermally stable, surviving the baking, roasting, and extrusion processes that can denature or destroy the allergenic proteins themselves. DNA sequences are also highly specific, allowing assays to distinguish sesame from botanically related species with confidence. Perhaps most importantly, the polymerase chain reaction, particularly its quantitative real-time variant known as qPCR, can amplify even vanishingly small amounts of target DNA into measurable signals, enabling trace-level detection that corresponds to the contamination scenarios that matter most in real food factories.

The efficiency of the entire detection chain, however, hinges on the extraction and purification step. Complex food samples contain fats, polyphenols, polysaccharides, and other inhibitors that can sabotage the enzymes used in PCR if they are not removed. Traditional liquid-phase extraction methods are labor-intensive and introduce multiple opportunities for sample loss and cross-contamination. Commercial spin-column kits standardize the process but come with recurring costs and limited flexibility. The miniaturized cartridge developed by the team aims to address these constraints by packing the DNA-binding solid phase into a small, self-contained format whose chemistry has been optimized specifically for allergen screening rather than for general-purpose nucleic acid work.

Controlled pore glass, the material at the heart of the new device, is a well-known medium in molecular biology: it is chemically robust, presents a high surface area for nucleic acid adsorption, and can be manufactured with precisely defined pore sizes. In the study, the researchers used this porous glass to capture DNA efficiently from processed samples and then release it cleanly for downstream analysis. By eliminating chaotropic salts from the protocol, the team simplified the workflow and reduced the chemical burden of the extraction, an important consideration for laboratories that process large numbers of samples and for portable or point-of-testing applications where harsh reagents are impractical.

The benchmark against a commercial kit is the most telling part of the evaluation. Despite yielding lower absolute quantities of DNA, in the range of approximately one to four nanograms per microliter, and purity ratios between roughly 0.8 and 1.2, values that look modest on paper compared with the numbers often quoted by conventional kits, the cartridge consistently delivered DNA that amplified successfully in qPCR assays. The researchers emphasize this point because amplifiability, not raw yield, is what ultimately determines whether an extraction method supports reliable allergen detection. A modest but clean extract that performs well in PCR is more useful than a high-volume extract riddled with inhibitors.

To test real-world performance, the team applied the cartridge to three challenging scenarios. In raw seeds, the device extracted DNA suitable for qPCR detection of sesame, one of the allergens for which mandatory labeling requirements have expanded in recent years in both the European Union and the United States. In commercial bakery mixes supplied by the Dutch company Sonneveld, the method successfully discriminated sesame-positive samples from negative ones, demonstrating that the extraction chemistry could cope with the sugars, fats, and starches that make baked goods among the most difficult matrices for DNA analysis. This discrimination capability is precisely what allergen control plans require: a clear, defensible answer about whether a prohibited ingredient is present.

The third scenario brought the technology out of the mixing bowl and onto the factory floor. Using swabs taken from stainless-steel coupons, the researchers showed that the cartridge could confirm the presence of sesame contamination at a surface density of 2.5 micrograms per square centimeter. Surface swabbing is a cornerstone of allergen management in food processing, because cross-contact between production runs on shared equipment is one of the most common routes by which undeclared allergens enter food. A verification method that works directly on swabs from processing surfaces gives quality teams a way to clear lines before the next product runs, potentially preventing recalls and protecting allergic consumers.

Beyond its analytical performance, the prototype’s most strategically significant feature may be its automation potential. Miniaturized cartridges with simplified, salt-free chemistry are natural candidates for integration into robotic liquid-handling platforms and microfluidic systems, where each pipetting step that can be removed from a protocol translates into faster turnaround, fewer errors, and lower costs. The work was carried out in part under the TITAN project, funded by the European Union’s Horizon Europe research and innovation program, which reflects the broader European push to strengthen food safety monitoring with advanced analytical technology.

The study, published open access with the DOI 10.1038/s41538-026-01196-6, arrives at a moment when allergen labeling regulations are tightening globally and the list of priority allergens continues to grow. Sesame alone became a newly mandatory label declaration in the United States in 2023, forcing many producers to re-evaluate their testing regimes. Tools that lower the barrier to sensitive, DNA-based allergen screening, whether applied to raw ingredients, complex premixes, or the surfaces of shared equipment, could meaningfully reduce the risk of undeclared allergens slipping through. While the device remains a prototype and further validation across additional allergens and matrices will be needed before it sees routine industrial use, the demonstration that a small controlled pore glass cartridge, run without chaotropic salts, can match a commercial kit where it counts, in amplifiable DNA and positive sample discrimination, marks a promising step toward faster, leaner, and more accessible allergen testing for the food industry.

Subject of Research: A miniaturized solid-phase extraction cartridge for DNA-based detection of food allergens

Article Title: A miniaturized solid-phase extraction cartridge for DNA-based detection of food allergens

Article References: Teixeira, C., Ipatov, A., Macedo, M., Popping, B., & Prado, M. (2026). A miniaturized solid-phase extraction cartridge for DNA-based detection of food allergens. npj Science of Food. https://doi.org/10.1038/s41538-026-01196-6

Image Credits: AI Generated

DOI: 10.1038/s41538-026-01196-6

Keywords: food allergens, DNA extraction, solid-phase extraction, controlled pore glass, qPCR, sesame, food safety, allergen detection, bakery mixes, surface swabbing, chaotropic salts, automation

The type 1 diabetes genetic risk score, or T1D-GRS, is a tool that has already proven its worth in diabetes prediction and classification. It aggregates information from ten single nucleotide polymorphisms, or SNPs—individual positions in the genome where the DNA letter varies between people and where certain variants shift the probability of developing the autoimmune form of diabetes. Because the score draws on genetic variants that remain stable throughout life, it can help distinguish type 1 from type 2 diabetes in young adults and identify individuals at elevated risk long before symptoms appear. Crucially, the T1D-GRS and islet autoantibodies, the immune markers that signal the body’s attack on insulin-producing cells, act as independent predictors of diabetes, which makes pairing them particularly powerful for screening and diagnostic purposes.

The obstacle has always been practical rather than scientific. To calculate the score, laboratories traditionally need genomic DNA extracted from white blood cells, which involves purification, quantification and storage steps that add expense at every turn, before a single genotyping reaction has even been set up. The Exeter team reasoned that this entire pipeline might be unnecessary. Serum, the very material already used for islet autoantibody assays, contains extracellular DNA released from cells that burst during the clotting process. If that DNA were sufficient for genotyping, the same tube of blood could serve both the antibody test and the genetic score, eliminating the need for a separate DNA extraction altogether.

There was a catch, however, and it lay in the biochemistry of clotting. The extracellular DNA in serum comes from leukocytes that rupture as the blood clots, so the amount of genomic DNA available depends on how long the sample is allowed to clot before being spun down in a centrifuge. Many standard serum processing protocols specify clotting times of less than thirty minutes, a window that previous work suggested may be inadequate for releasing enough genomic DNA into the fluid. The researchers therefore designed their study to answer two linked questions: whether a direct-from-serum genotyping method could calculate the ten-SNP T1D-GRS accurately, and how strongly the answer depended on clotting time.

The technical setup was deliberately conventional, which is part of the method’s appeal. The team used TaqMan SNP genotyping assays, a widely adopted fluorescence-based qPCR chemistry, together with TaqPath ProAmp Master Mix, in tiny five-microliter reactions containing just one microliter of either purified DNA or raw serum. Plates, prepared on a Biomek i7 Automated Workstation and run for fifty cycles on a QuantStudio 12K Flex Real-Time PCR System, included positive and no-template controls, and genotypes were called automatically using commercial software. In other words, nothing exotic was required—only standard reagents, standard instruments and a single microliter of serum per SNP.

Accuracy came first. In a cohort of 116 matched serum and whole-blood-derived DNA samples sent to the Exeter Genomics Laboratory from across the UK and Ireland, all with clotting times exceeding 24 hours, both biospecimens achieved call rates above 95 percent across all ten SNPs on the first pass, with no repeated reactions. A complete T1D-GRS was obtained from 84.5 percent of serum samples compared with 96.6 percent of purified DNA samples, a statistically significant difference, but among the 94 samples where both approaches yielded a complete score, the results agreed perfectly—100 percent concordance. In a subset of 32 samples with sequencing data available, the serum-derived scores were again fully concordant, confirming that the shortcut does not come at the cost of correctness.

The clotting-time experiment revealed where the method’s limits lie. The team analyzed 122 serum samples with recorded clotting times ranging from 12 to 475 minutes, running every sample in duplicate on separate qPCR runs to check reproducibility. Splitting the cohort at the thirty-minute mark produced a striking contrast. Samples clotted for thirty minutes or less achieved a genotyping success rate of just 68.8 percent, a replicate discordance rate of 28.8 percent, and yielded a complete ten-SNP score in only 7.4 percent of cases. Samples clotted for longer than thirty minutes, by comparison, reached a 97 percent genotyping success rate, only 2.2 percent replicate discordance, and complete scores in 77.8 percent of samples—a difference the authors report as highly significant. Performance in this longer-clotting group closely matched that of the samples clotted for more than 24 hours.

The explanation, the researchers argue, is straightforward: insufficient clotting time leaves too little extracellular DNA in the serum for reliable amplification. This aligns with earlier findings that PCR-based genotyping from samples containing very low DNA concentrations—below roughly 56 picograms—is unreliable. The practical message for laboratories hoping to combine genetic and biochemical testing is that serum should be allowed to clot for more than thirty minutes before processing, a duration that does not compromise autoantibody assays. Where additional tests sensitive to proteolysis, glycolysis or other degradation processes are needed, the authors suggest an intermediate clotting window of more than thirty minutes but under about three hours may offer the optimal balance between DNA release and analyte preservation.

The implications extend well beyond the immediate assay. A direct-from-serum approach could unlock cost-effective genotyping in the many large frozen serum biobanks around the world where no extracted DNA exists, allowing researchers to mine decades of stored samples for genetic risk information without retrieving new blood draws. Although the study tested only ten SNPs, the low input volume of one microliter per SNP suggests the same logic could scale to larger genotyping panels or alternative genotyping chemistries. For clinical laboratories that lack DNA-extraction capability, the proof-of-principle result points toward direct, automated assays that run antibody and genetic tests in parallel from a single serum sample. The work was supported by the National Institute for Health and Care Research Exeter Biomedical Research Centre, and the authors note existing research funding and licensing arrangements with Randox Laboratories to develop a T1D-GRS assay, underscoring the translational momentum behind the approach. If the method holds up in broader validation, the humble serum tube—already the workhorse of clinical chemistry—may become a one-stop source for both immune and genetic markers of diabetes risk.

Subject of Research: A direct-from-serum genotyping method for calculating a type 1 diabetes genetic risk score

Article Title: A direct-from-serum method for calculating a type 1 diabetes genetic risk score

Article References: Spurrier, B., Oram, R. A., Thomas, N. J., & Locke, J. M. (2026). A direct-from-serum method for calculating a type 1 diabetes genetic risk score. Journal of Translational Medicine, 24(1), Article 1148. https://doi.org/10.1186/s12967-026-08930-4

Image Credits: AI Generated

DOI: 10.1186/s12967-026-08930-4

Keywords: type 1 diabetes, genetic risk score, serum, genotyping, TaqMan, qPCR, SNP, islet autoantibodies, DNA extraction, clotting time, biobanks, precision medicine