The research team, led by Ye Cheng and Dawo Liu of Shengjing Hospital Affiliated to China Medical University together with colleagues at Liaoning University, confronted a problem that has long frustrated the field of nanotoxicology. Individual studies of nanomaterial toxicity have produced wildly inconsistent findings. Some experiments report alarming damage to the liver, kidneys, or reproductive organs; others find little or no effect. The discrepancies stem from the sheer diversity of the materials themselves, which differ in chemical composition, size, shape, surface charge, and coating, as well as from differences in experimental design, including dose, exposure route, duration, and animal strain. A single laboratory study, however carefully conducted, cannot resolve that noise. A meta-analysis can. By combining the results of many independent experiments into a single statistical framework, the method transforms scattered, contradictory data into a coherent estimate of overall effect, and allows researchers to test which variables drive the differences between studies.

The team focused on three families of biological indicators that together sketch a portrait of systemic harm. The first is serum biochemistry, the battery of enzymes and metabolites that clinicians use to judge whether organs such as the liver and kidneys are functioning properly. When liver cells are damaged, for example, enzymes like alanine aminotransferase leak into the blood, and levels rise measurably. The second family is oxidative stress, the imbalance that arises when reactive oxygen species, chemically aggressive molecules generated in abundance during normal metabolism, overwhelm the body’s antioxidant defenses. Pro-oxidant markers rise, antioxidant markers fall, and the resulting damage strikes lipids, proteins, and DNA alike. The third family is genotoxicity, indicators of direct injury to the genetic material itself, including DNA strand breaks and chromosomal damage. Together, these endpoints capture harm at every level from organ function down to the genome.

The pooled results were unambiguous. Across the analyzed studies, nanomaterial exposure significantly increased the levels of serum biochemical parameters related to organ function, with statistical significance at the conventional threshold of p less than 0.05. In plain terms, the livers and kidneys of exposed animals showed measurable signs of stress or damage compared with unexposed controls. The oxidative stress picture was equally clear: nanomaterials significantly elevated pro-oxidant levels while simultaneously depressing antioxidant levels, tilting the internal redox balance toward damage. This dual shift is the classic signature of oxidative stress, and it matters because oxidative damage is implicated in inflammation, cell death, and the progression of chronic disease. Finally, the meta-analysis found that nanomaterial exposure significantly increased indicators of DNA and chromosomal damage, providing quantitative evidence of genotoxicity in living animals rather than only in isolated cells.

Perhaps the most valuable contribution of the study lies in its subgroup analyses, which dissected how the toxic effects vary with the properties of the nanomaterial and the conditions of exposure. The analysis found that metal-based nanomaterials, such as those containing titanium, silver, copper, or zinc, produced stronger toxic effects than their non-metal counterparts. This is biologically plausible: metal nanoparticles can release metal ions inside cells, and those ions catalyze the production of reactive oxygen species through well-characterized Fenton-type reactions. Size mattered too. Particles of 50 nanometers or smaller were more toxic than larger ones, consistent with the principle that smaller particles present a greater surface area per unit mass, dissolve and release ions more readily, and penetrate biological barriers more efficiently. The smaller the particle, the more of its reactive surface comes into contact with living tissue.

Exposure conditions proved equally decisive. Toxic effects intensified with longer exposure durations and higher doses, a dose-response relationship that strengthens the case for a genuine causal effect rather than a statistical artifact. The analysis also revealed variations across exposure routes, meaning that the way nanomaterials enter the body, whether by ingestion, inhalation, injection, or skin contact, shapes the pattern and severity of harm. Different routes deliver particles to different organs at different concentrations, and the body’s defenses, from gut enzymes to lung macrophages, intercept particles with varying success depending on the portal of entry. Tissue-specific differences emerged as well, reflecting the fact that organs such as the liver and spleen, which filter particles from the blood, accumulate nanomaterials to a far greater extent than tissues that are more sheltered from circulation.

These findings arrive at a moment when human exposure to nanomaterials is expanding rapidly. Engineered nanoparticles are already embedded in food additives, cosmetics, packaging, textiles, electronics, and an ever-growing list of medical products, from contrast agents to drug-delivery vehicles. Natural and incidental nanomaterials, produced by volcanoes, wildfires, and industrial combustion, pervade the environment as well, as researchers have emphasized in landmark assessments of nanomaterials in the Earth system. Regulatory agencies worldwide have struggled to keep pace, in part because the very properties that make nanomaterials useful also make their behavior unpredictable in biological systems. A nanoparticle is not simply a miniature version of the same bulk chemical; its surface reactivity, solubility, and interactions with proteins and membranes can differ fundamentally from those of larger particles of identical composition.

The mechanistic thread running through the meta-analysis, oxidative stress, connects the observed biochemical and genetic damage into a coherent narrative. Nanoparticles entering cells can disturb mitochondria, the energy-producing organelles that generate reactive oxygen species as a byproduct of respiration. They can also trigger inflammatory responses that flood tissues with additional oxidants, and deplete antioxidant molecules such as glutathione that normally keep the damage in check. When the antioxidant defenses fail, lipid membranes are peroxidized, proteins are misfolded, and DNA repair machinery falls behind the rate of injury, allowing strand breaks and chromosomal aberrations to accumulate. Previous meta-analyses of specific materials, including nano-titanium dioxide and copper oxide nanoparticles, have reported similar oxidative and genotoxic patterns, and the new study extends that evidence across the broader universe of engineered nanomaterials.

The authors are careful to frame their results as a foundation for risk assessment rather than a verdict on nanotechnology itself. The experiments analyzed involve controlled, often high-dose exposures in rodents, and the findings cannot be mapped directly onto typical human exposures, which are generally lower and more diffuse. Nevertheless, the quantitative evidence that nanomaterials induce significant biochemical, oxidative, and genotoxic effects in animal models, with toxicity shaped predictably by particle composition, size, dose, duration, and route, gives regulators and manufacturers something they have long lacked: a structured basis for hazard evaluation. By identifying which materials and exposure scenarios carry the greatest risk, the analysis can guide the design of safer nanomaterials, inform testing priorities, and support exposure limits that reflect the genuine biology of these remarkable but potentially hazardous substances.

What makes the study resonate beyond the laboratory is the sheer scale of the nanomaterial economy and the speed at which it is growing. Every year, new nano-enabled products reach consumers, and new nanostructures are proposed for medicine, energy, and environmental remediation, often before their toxicological profiles are fully understood. The Liaoning team’s work, supported by the Liaoning Province Natural Science Foundation and the Liaoning Provincial Department of Education, demonstrates the power of systematic, quantitative synthesis to cut through the noise of hundreds of individual experiments and deliver a clear signal. As nanomaterials continue their migration from the laboratory into food, medicine, and the environment, that signal, small particles, especially metal-based ones, can inflict real biological damage under the right conditions, is one that industry, regulators, and the public can no longer afford to ignore.

Subject of Research: In vivo toxicity of engineered nanomaterials in rats and mice assessed by meta-analysis

Article Title: Potential toxicity of nanomaterials on rats/mice: a meta-analysis

Article References: Cheng, Y., Gao, X., Wang, J., Zhao, X., Cao, X., & Liu, D. (2026). Potential toxicity of nanomaterials on rats/mice: a meta-analysis. Environmental Geochemistry and Health, 48(14), Article 577. https://doi.org/10.1007/s10653-026-03473-5

Image Credits: AI Generated

DOI: 10.1007/s10653-026-03473-5

Keywords: nanomaterials, nanotoxicology, meta-analysis, oxidative stress, genotoxicity, serum biomarkers, rodent studies, metal-based nanoparticles, risk assessment, DNA damage, Environmental Geochemistry and Health, Potential

Angelica gigas, known in Korea as Dang-gui, has long been used to treat inflammation, pain, and circulatory complaints. Its roots are rich in decursin and decursinol angelate, two closely related coumarin compounds that earlier work had already linked to anti-inflammatory activity. What remained unclear was a deceptively simple question: how much of the whole extract’s effect do these two compounds actually account for? If they explain most of the activity, then a defined mixture of the two could stand in for the extract, bringing the consistency and quality control that modern pharmacology demands. If they explain only part of it, then other constituents must be doing significant work, and simplifying the extract could sacrifice efficacy.

To answer that question, the team designed a head-to-head experiment in RAW264.7 macrophages, a widely used mouse cell line for studying innate immunity. They inflamed the cells with lipopolysaccharide, or LPS, a component of the outer membrane of Gram-negative bacteria that reliably triggers a potent inflammatory program. They then compared two treatments at carefully matched doses: the whole Angelica gigas root ethanol extract at 40 micrograms per milliliter, and an extract-equivalent mixture of the two pure coumarins, calibrated to 17.7 micromolar decursin and 5.99 micromolar decursinol angelate, the concentrations at which these compounds naturally occur in that amount of extract. This extract-equivalent design is the study’s methodological backbone, because it ensures that any difference between the two treatments reflects the contribution of other extract constituents rather than unequal dosing.

The results were striking in their symmetry. The decursin plus decursinol angelate mixture suppressed the LPS-driven expression of three central inflammatory cytokine genes, Tnf, Il1b, and Il6, whose protein products drive fever, tissue damage, and the recruitment of further immune cells. In direct comparisons, the mixture reduced these cytokine mRNAs to roughly the same extent as the whole extract. The two coumarins also matched the extract in tamping down nuclear factor-kappa B, or NF-kB, the master transcription factor that switches on inflammatory genes. Under inflammatory stimulation, NF-kB moves from the cytoplasm into the nucleus, where it binds DNA and activates dozens of target genes; both the extract and the compound mixture curtailed this nuclear localization to a comparable degree.

The anti-inflammatory fingerprint extended beyond cytokines and NF-kB. Both treatments reduced the accumulation of reactive oxygen species, the chemically reactive molecules that macrophages produce during inflammatory bursts and that can damage surrounding tissue while amplifying inflammatory signaling. The mixture also mirrored the extract in lowering the levels of NLRP3, pro-IL-1beta, and IL-18, three proteins tied to the inflammasome, a multi-protein molecular machine inside macrophages that processes immature IL-1beta and IL-18 into their mature, potent inflammatory forms. NLRP3 inflammasome overactivation has been implicated in a wide range of diseases, from gout and atherosclerosis to metabolic syndrome and neurodegeneration, so a botanical compound pair that restrains this machinery at its source is of considerable pharmacological interest.

Notably, the study found no apparent enhancement when the two compounds were combined, at least under the concentrations tested. Decursin and decursinol angelate each dampened the inflammatory markers on their own, and mixing them at extract-equivalent ratios did not produce a synergistic boost beyond what either compound achieved individually. This suggests that the two coumarins act through overlapping or parallel mechanisms rather than complementary ones, and that their combined presence in the root is a matter of natural abundance rather than a finely tuned synergistic partnership. For product developers, that is a simplifying result: a single well-characterized compound, or a simple fixed-ratio pair, may capture most of the relevant activity.

The story was not entirely one of equivalence, however. When the researchers probed deeper into the cellular stress landscape, they found that the whole extract did not broadly reverse the changes that LPS imposed on genes governing the integrated stress response, a cellular signaling network activated when protein folding in the endoplasmic reticulum goes awry, or on genes involved in mitochondrial proteostasis, the quality-control system that keeps the mitochondrion’s own protein machinery in working order. In other words, LPS reshapes a wider swath of the macrophage’s stress physiology than the extract or the coumarin pair fully counteracts, and the anti-inflammatory effects documented here do not extend to a wholesale restoration of stress-response gene expression.

That nuance matters for interpretation. The authors conclude that decursin and decursinol angelate are major contributors to the anti-inflammatory and antioxidant effects of the Angelica gigas extract, while explicitly leaving room for other constituents to play supporting roles. The extract contains a complex cocktail of coumarins, polyacetylenes, and phenolic compounds, and the present data cannot rule out that some of these contribute to effects the two-compound mixture did not fully capture, particularly in the stress-response pathways that remained largely unresponsive. The extract-equivalent design means that any residual activity of the whole extract beyond the mixture would be attributable to those minor components, and mapping them is a natural next step for the field.

The broader significance lies in the tension between traditional botanical medicine and modern standardization. Crude herbal extracts vary with plant genetics, growing conditions, harvest timing, and processing, making dose consistency difficult and clinical trial interpretation messy. Prior studies had already shown that decursin blocks NF-kB activation in macrophages and that decursinol angelate modulates NF-kB and MAPK signaling, but this study is distinctive in quantifying how far two defined molecules go toward reproducing a whole extract at matched concentrations. If subsequent work in additional cell types and in vivo models confirms the equivalence, Angelica gigas preparations could be reformulated around standardized decursin and decursinol angelate content, improving reproducibility and enabling precise dosing in future clinical studies of inflammation-related conditions.

For now, the findings rest on a single macrophage cell line and LPS as the inflammatory trigger, so extrapolation to human inflammation requires caution. Yet the mechanistic picture is coherent: two pyranocoumarins from a traditional medicinal root converge on NF-kB nuclear translocation, cytokine gene expression, reactive oxygen species accumulation, and inflammasome-related protein levels, matching the extract that contains them. It is a textbook example of pharmacognosy doing what it does best, taking an ancient remedy apart molecule by molecule to find out which pieces actually work. In this case, the answer appears to be that a great deal of Dang-gui’s anti-inflammatory reputation can be carried by two compounds small enough to name, dose, and one day perhaps prescribe.

Subject of Research: Anti-inflammatory activity of decursin and decursinol angelate from Angelica gigas root extract in macrophages

Article Title: Extract-equivalent decursin and decursinol angelate reproduce major anti-inflammatory effects of Angelica gigas root ethanol extract in LPS-stimulated macrophages

Article References: Kim, K., Kim, M.-B., Baek, S., Kumagai, Y., Go, G.-W., Cao, L., & Lee, S. (2026). Extract-equivalent decursin and decursinol angelate reproduce major anti-inflammatory effects of Angelica gigas root ethanol extract in LPS-stimulated macrophages. Food Science and Biotechnology. https://doi.org/10.1007/s10068-026-02227-4

Image Credits: AI Generated

DOI: 10.1007/s10068-026-02227-4

Keywords: Angelica gigas, decursin, decursinol angelate, macrophages, inflammation, NF-kB, NLRP3 inflammasome, cytokines, reactive oxygen species, pyranocoumarins, LPS, natural products

The plateau sits at 39 degrees 37 minutes north latitude and 67 degrees 56 minutes east longitude, in a region characterized by a dry continental climate. That combination of altitude and aridity matters because astronomers care about two things above almost all else: how much the atmosphere blurs incoming light, and how much it absorbs incoming millimeter and radio waves. Water vapor is the chief villain in both cases. In the optical it contributes to turbulence and image degradation, while in the millimeter-wave bands it is the dominant source of atmospheric absorption, degrading the sensitivity of radio telescopes and corrupting the phase coherence needed for interferometry. A site that keeps both problems in check is worth serious attention.

On the optical side, the researchers deployed a Differential Image Motion Monitor, or DIMM, the same class of instrument pioneered by the European Southern Observatory for site testing worldwide. A DIMM works by observing a bright star through a small telescope with a two-aperture mask and measuring the differential motion of the resulting star images. Because both images share the same large-scale wavefront tilts, their relative jitter isolates the turbulence-induced blurring that astronomers call seeing. The nighttime measurements at Suffa yielded a median seeing of 1.06 arcseconds and a mean of 1.11 arcseconds, values that indicate relatively stable optical observing conditions for a significant fraction of the year. While not rivaling the very best sub-arcsecond sites on Earth, such seeing is competitive for a wide range of optical and infrared programs and suggests the plateau can support diffraction-limited work on moderate apertures with adaptive optics assistance.

The more distinctive part of the study, however, lies in the millimeter-wave domain. The team used a dual-channel instrument, the MIAP-2 radiometer, operating in two atmospheric windows: 84 to 99 gigahertz, corresponding to the 3-millimeter band, and 132 to 148 gigahertz, corresponding to the 2-millimeter band. These windows straddle the steeply rising atmospheric opacity that makes short-wavelength radio astronomy so demanding, and their transparency is governed largely by the total column of water vapor above the telescope, known as precipitable water vapor or PWV. At Suffa, the median atmospheric absorption measured 0.13 nepers in the 2-millimeter channel and 0.11 nepers in the 3-millimeter channel, with means of 0.14 and 0.12 nepers respectively, reflecting a site that is usefully transparent across much of the year.

Because the 2-millimeter channel is more sensitive to water vapor, the researchers used it exclusively for quantitative PWV retrievals, deriving median and mean values of 4.96 and 5.91 millimeters. The 3-millimeter channel, by contrast, served primarily to characterize dry atmospheric opacity and long-term transparency trends, providing a complementary record of how the atmosphere behaves even when the wet component is minimal. This two-channel strategy, long used by site-testing groups from the Atacama Desert to the South Pole and Greenland, allows the separation of the water-vapor contribution from the oxygen and ozone background that sets a floor on absorption at any ground-based site.

Seasonality emerged as one of the clearest signals in the dataset. Winter months, particularly January and February, offer the most favorable conditions for millimeter-wave observations, with atmospheric absorption dropping by approximately 50 percent relative to the annual mean. That winter bonus is a direct consequence of the continental climate: cold air holds far less water vapor, and the plateau’s altitude places the telescope above a substantial fraction of the remaining humid column. For planners of future millimeter facilities, the message is practical. The observing calendar at Suffa would naturally front-load the most demanding projects, such as sensitive spectral-line surveys and continuum imaging of cold dust, into the deepest winter months, while summer programs could favor optical work and less atmosphere-sensitive radio observations.

To guard against instrumental bias, the team cross-checked their radiometric PWV retrievals against the ERA5 atmospheric reanalysis, a widely used global dataset produced by assimilating observations into a numerical weather model. The comparison confirmed the general reliability of the radiometer-derived humidity values and their seasonal consistency, lending independent weight to the site statistics. Reanalysis data cannot replace in situ measurements at the resolution a telescope designer needs, but agreement between the two builds confidence that the measured numbers reflect genuine climatological behavior rather than calibration artifacts or unlucky sampling periods.

Another factor the study highlights is the low level of radio-frequency interference at the plateau. As the radio spectrum grows increasingly crowded by communications and satellite traffic, quiet spectrum has become as scarce a resource as dark skies. Interference degrades passive observations and, in extreme cases, renders entire bands unusable, a concern the American Meteorological Society has flagged in its policy work on passive remote sensing. A protected, sparsely populated high-altitude valley therefore offers more than clean air; it offers an electromagnetic environment in which faint cosmic signals can actually be detected.

The findings carry particular weight for regional astronomy infrastructure. Uzbekistan already operates the Maidanak Observatory, whose optical seeing has been monitored for decades with DIMM instruments and which has long served as the country’s flagship optical site. Characterizing Suffa in parallel establishes a complementary capability: Maidanak for optical and infrared astronomy, and Suffa for millimeter-wave and radio work. The most immediate driver is the RT-70 radio telescope currently under development on the plateau, a large-aperture facility whose scientific productivity will depend directly on the transparency statistics this study quantifies. Precise knowledge of median absorption, PWV distributions, and seasonal windows feeds into everything from receiver band selection and calibration strategy to observing-efficiency estimates and the scheduling of very long baseline interferometry sessions, for which stable atmospheric phase is critical.

More broadly, the study adds a well-characterized northern-hemisphere, mid-latitude site to the global inventory of places where the sub-terahertz universe can be reached from the ground. Previous site searches across Eurasia, together with long-running campaigns at Chajnantor, Mauna Kea, Pampa la Bola, and the Greenland summit, have shown that excellent millimeter conditions cluster in a handful of high, dry locations. The Suffa Plateau now has the long-term data to argue for inclusion in that short list. For a significant fraction of the year, its combination of moderate seeing, low absorption, low precipitable water vapor, and quiet spectrum makes it a credible home for the next generation of optical, radio, and millimeter-wave facilities, and a reminder that the map of world-class observing sites is still being drawn.

Subject of Research: Astroclimatic and atmospheric characterization of the Suffa Plateau in Uzbekistan for optical, millimeter-wave, and radio astronomical observations.

Article Title: Astroclimatic conditions of the Suffa Plateau: optical and radiophysical parameters

Article References: Tursunkulov, S. B., & Raupov, D. A. (2026). Astroclimatic conditions of the Suffa Plateau: optical and radiophysical parameters. Astrophysics and Space Science, 371(9), Article 103. https://doi.org/10.1007/s10509-026-04617-w

Image Credits: AI Generated

DOI: 10.1007/s10509-026-04617-w

Keywords: Suffa Plateau, astroclimate, astronomical seeing, precipitable water vapor, atmospheric absorption, millimeter-wave astronomy, DIMM, radiometry, radio-frequency interference, ERA5 reanalysis, RT-70 radio telescope, site testing

This nonlinearity is particularly intriguing because the harbor spans a seasonal temperature range that roughly brackets the transition observed in the data. At cooler temperatures, fungal assemblages may be constrained by slower metabolic rates and a narrower pool of viable colonists, producing communities dominated by cosmopolitan taxa capable of tolerating brackish conditions. As temperatures climb toward 30 °C, the metabolic pace of microbial life accelerates dramatically, shortening generation times and intensifying competition. Species with rapid growth rates and broad substrate tolerances, such as many yeasts in the Candida clade, can then outpace slower-growing filamentous fungi and capture a disproportionate share of available resources. The more than 60 percent sequence share held by Candida parapsilosis in the warm-season samples is consistent with this kind of competitive release under favorable thermal conditions.

The ecological interpretation of that dominance deserves careful attention. Candida parapsilosis is an opportunistic yeast frequently recovered from hospital environments, medical devices, human skin, and contaminated water systems, and it ranks among the leading causes of invasive candidiasis in some clinical settings. Its abundance in harbor surface water at 20 °C does not prove that the harbor is a reservoir of active infection risk, but it does indicate that conditions in the port, together with inputs from surrounding urban and industrial landscapes, can sustain a substantial population of a recognized human pathogen. The authors’ attribution of this input to human-impacted coastal freshwater sources fits the harbor’s geography, since the Yangtze River drains one of the most densely populated and industrially intensive regions on Earth before mixing into the estuary where the harbor sits.

The salinity gradient documented in the harbor, ranging roughly from 10 to 23 parts per thousand, places it squarely within the brackish zone where freshwater and marine microbial assemblages intermingle. Brackish systems are inherently dynamic because the balance between river discharge and tidal exchange shifts with season, weather, and upstream water management. Fungi face distinct osmotic challenges on either end of this gradient, and only taxa with sufficient physiological flexibility can persist across it. The observation that harbor communities more closely resemble seawater assemblages than freshwater ones suggests that marine influence, likely mediated by tidal exchange with the East China Sea, exerts a stronger filtering effect than riverine input, even though the river supplies the nutrient and sediment loads that make the harbor biologically productive.

The contribution of bacterial communities to fungal diversity adds an important biotic dimension to the picture. Bacteria and fungi interact in myriad ways: bacteria can consume fungal exudates, inhibit fungal growth through antibiotic production, facilitate fungal access to nutrients, or form biofilms in which both groups jointly structure the microenvironment. Prior work in the harbor has documented extraordinary viral diversity, and viruses can regulate bacterial populations that in turn shape fungal success. The finding that bacterial community structure co-influences fungal patterns indicates that fungal assembly in the harbor is not governed by temperature alone but emerges from a web of cross-kingdom interactions. Such coupled dynamics are increasingly recognized in microbiome research, where the stability of a community often depends on the integrity of multiple interacting subsets rather than on any single taxonomic group.

The relatively low ecological stability observed in the harbor’s fungal assemblages is noteworthy in this context. Stability in microbial ecology refers to the degree to which a community resists perturbation or returns to its original composition after disturbance. Habitats subjected to frequent physical, chemical, and biological disturbances, such as dredging, ship traffic, sediment resuspension, and fluctuating freshwater input, tend to host communities that never settle into a predictable steady state. The harbor experiences approximately one hundred vessel arrivals each day, and its bed accumulates sediment seasonally as the Yangtze delivers its load. Each of these events can rework the microbial landscape, and a community already destabilized by strong temperature-driven turnover may have limited capacity to buffer additional shocks.

Methodologically, the study’s reliance on the internal transcribed spacer 1 region reflects standard practice in fungal environmental sequencing, and it carries both strengths and limitations worth appreciating. The ITS region is variable enough to discriminate most fungal species, which is why it was designated the official fungal barcode marker. However, ITS copy number varies widely among taxa, so sequence abundance is an imperfect proxy for organismal abundance. Furthermore, the finding that 1,344 operational taxonomic units, representing more than half of all recovered sequences, remained unclassified underscores how poorly inventoried aquatic mycobiomes remain. A large fraction of these unclassified lineages may belong to understudied marine clades whose ecological roles are still unknown, hinting at substantial undiscovered fungal diversity in coastal waters.

The dominance of Ascomycota and Basidiomycota aligns with patterns reported from other coastal and offshore systems worldwide. Ascomycetes, which include many yeasts and filamentous decomposers, often dominate planktonic and coastal waters where labile organic matter is plentiful. Basidiomycetes, including the marine-derived yeasts of the class Agaricomycotina and the enigmatic deep-sea lineages, tend to occupy niches associated with more recalcitrant substrates or deeper waters. The harbor’s mixed character, receiving both estuarine particulates and offshore water, likely supports representatives of both phyla in proportions that shift with season and hydrographic conditions, making it a natural laboratory for studying how marine and terrestrial fungal lineages partition a shared habitat.

From a public health perspective, the presence of opportunistic fungal pathogens in a major port raises questions about surveillance and management that coastal authorities are only beginning to confront. Ports concentrate shipping traffic from around the globe, and ballast water discharge is a well-established vector for transferring microorganisms between distant ecosystems. Whether pathogenic yeasts detected in harbor water arise primarily from local freshwater inputs, from ship-associated sources, or from a combination of both remains an open question that the study’s source-attribution analysis only partially resolves. The possibility that warming trends could increase the seasonal window during which thermotolerant opportunists thrive adds urgency, since many Candida species grow optimally near mammalian body temperature, a trait that underlies their pathogenic potential.

The study’s temperature-stratified design, sampling at 10, 20, and 30 degrees Celsius across the harbor and at adjacent freshwater and seawater reference sites, provides a template for future comparative work in anthropogenically influenced coastal systems. Few studies have paired a major port with matched freshwater and marine reference locations, and the ability to compare communities across these three habitats at equivalent temperatures strengthens causal inference about sources and sinks of fungal diversity. Composite sampling that pooled water from representative sites helped average out small-scale heterogeneity, an important consideration in turbulent harbor waters where patchiness can be extreme.

Broader environmental change scenarios lend this work additional significance. Coastal water temperatures in the East China Sea have been rising in concert with regional and global trends, and estuarine systems like the Yangtze mouth face compounding pressures from altered river discharge, nutrient enrichment, and continued shoreline development. If temperature indeed governs fungal community structure as strongly as this study suggests, then gradual warming could progressively shift these communities toward warm-adapted assemblages, with unknown consequences for organic matter processing, algal bloom dynamics, and pathogen prevalence. Monitoring programs that track fungal assemblages alongside bacterial and viral ones, using standardized barcode sequencing and consistent seasonal sampling, would help distinguish long-term directional change from the natural variability of a naturally unstable habitat.

Finally, the study contributes to a growing appreciation that fungi, long understudied relative to bacteria in marine systems, deserve a central place in coastal microbiology. The harbor’s fungal communities, shaped simultaneously by temperature, salinity, bacterial interactions, hydrodynamic exchange, and human activity, exemplify the multicausal nature of microbial biogeography. Understanding these interacting forces in one of the world’s busiest container ports offers a lens on how coastal ecosystems everywhere may respond as human pressures on the marine environment continue to intensify.

Subject of Research: Temperature-driven shifts in fungal community structure and potential pathogen prevalence in the surface water of Yangshan Deep-Water Harbor

Article Title: Temperature-driven shifts in fungal community structure and potential pathogen prevalence in the surface water of Yangshan Deep-Water Harbor

Article References: Wang, X., Xiao, J., Han, J., Pan, W., Liao, W., Bo, P., & Wang, Y. (2026). Temperature-driven shifts in fungal community structure and potential pathogen prevalence in the surface water of Yangshan Deep-Water Harbor. Ocean Microbiology, 2(1), Article 2. https://doi.org/10.1186/s44375-026-00009-1

Image Credits: AI Generated

DOI: 10.1186/s44375-026-00009-1

Keywords: Temperature-driven, shifts, fungal, community, structure, potential, pathogen, prevalence, surface, water, Yangshan, Deep-Water

BEST4⁺ cells are defined by a distinctive combination of genes, including BEST4, OTOP2, CA7 and GUCY2C. In the small intestine, they also show particularly high expression of CFTR, the chloride and bicarbonate channel best known for its role in cystic fibrosis. Together, these markers suggest a specialized role in moving negatively charged ions across the epithelium. Chloride and bicarbonate transport draw water into or out of the intestinal lumen and help regulate the chemical environment surrounding epithelial cells and mucus. OTOP2 adds a sensing capability: this proton-selective channel can respond to changes in extracellular acidity. CA7 may support intracellular bicarbonate production, while GUCY2C encodes guanylyl cyclase C, a receptor that converts extracellular signals into cyclic GMP. The resulting molecular profile is unusually coherent for a relatively small cell population.

The cells were first associated with the intestinal epithelium through studies of bestrophin expression, but modern single-cell sequencing made their identity much clearer. These analyses separate individual epithelial cells according to their RNA profiles, allowing researchers to identify populations that conventional staining can overlook. BEST4⁺ cells appear early in human intestinal development, reportedly as early as gestational week 11, and generally represent less than 5 percent of the fetal epithelial compartment. In adults, their abundance varies by region, with reported enrichment in parts of the jejunum, ileum and colon. Small-intestinal cells are concentrated toward the upper and middle villus, whereas colonic cells tend to occupy apical crypt regions. The regional differences suggest that a shared core program may be adapted to local pH, microbial exposure, mucus and transport demands.

The developmental identity of BEST4⁺ cells is still being debated. Several lines of evidence place them near the end of an absorptive differentiation pathway. They occupy post-mitotic compartments, lack conventional proliferation markers and express genes associated with mature enterocytes and colonocytes, including VIL1, AQP8 and SLC26A3. Human organoid experiments indicate that NOTCH signaling is required for their emergence, and the transcription factor SPIB appears indispensable: removing SPIB with CRISPR-based gene editing prevented BEST4⁺ cell generation even when NOTCH signaling remained active. Yet other findings point toward connections with the secretory lineage. Trajectory analyses in human tissue have identified a low-probability link to ATOH1-positive secretory progenitors, while zebrafish lineage-tracing experiments suggest that related cells can arise from secretory precursors. These differences may reflect species, anatomical region or inflammatory state rather than a single universal developmental route.

Under normal conditions, BEST4⁺ cells may act as coordinated pH and ion-transport units. BEST4 belongs to the bestrophin family of calcium-activated anion channels, which can conduct chloride and bicarbonate when intracellular calcium rises. CFTR provides another major route for apical anion secretion. The cells also express guanylin and uroguanylin, the endogenous ligands for GUCY2C, alongside the receptor itself. This arrangement could create an autocrine circuit in which locally produced ligands stimulate cyclic GMP, activate downstream protein kinases and increase CFTR activity. Bicarbonate secretion is important beyond fluid balance: it helps neutralize acidity near the epithelial surface and allows newly released MUC2 mucin to hydrate and expand into an effective protective layer. The review therefore proposes that BEST4⁺ cells may support mucus-barrier assembly in cooperation with goblet cells, although direct proof that these cells provide the critical bicarbonate flux is still lacking.

The same machinery can be exploited during secretory diarrhea. Bacterial heat-stable enterotoxin, or STa, binds and activates GUCY2C, raising intracellular cyclic GMP and stimulating CFTR through protein kinase G. Cholera toxin and the heat-labile toxin of enterotoxigenic Escherichia coli activate adenylate cyclase through persistent cyclic AMP signaling, leading to protein kinase A-mediated CFTR activation. In both cases, excessive chloride and bicarbonate secretion promotes water movement into the lumen. The review highlights evidence that BEST4⁺ cells are unusually equipped for this response because they co-express GUCY2C and CFTR at functionally relevant levels. Human intestinal organoids exposed to these pathways swell as fluid accumulates. Investigational inhibitors of GUCY2C or CFTR can reduce secretion in experimental systems, but broad suppression carries risks because basal GUCY2C signaling also contributes to barrier integrity, mucus hydration and epithelial maintenance.

Viral diarrhea may involve BEST4⁺ cells more indirectly. Porcine epidemic diarrhea virus preferentially damages villus absorptive enterocytes and can impair NHE3, a sodium-hydrogen exchanger needed for sodium-coupled water absorption. Studies in infected piglets have reported reduced expression of several water and nutrient transporters, together with increased ileal CFTR transcripts. Electrical measurements of infected jejunal tissue also indicate enhanced secretory responses. These observations are consistent with a shift away from absorption and toward secretion, and the presence of CFTR-rich BEST4⁺ cells makes them plausible contributors. But the available evidence does not show that the virus infects BEST4⁺ cells or that the cells are responsible for the altered current. Rotavirus offers another possible route: its NSP4 protein disturbs calcium signaling and triggers ADP-dependent calcium waves in neighboring uninfected cells. BEST4⁺ cells could respond as bystander effectors through calcium-sensitive anion channels, but this remains a testable hypothesis.

Norovirus likewise causes changes that could intersect with the BEST4⁺ program, including reduced epithelial resistance and increased electrogenic chloride secretion. The virus can replicate in differentiated enterocytes and some enteroendocrine cells, but there is no direct evidence that mature BEST4⁺ cells support norovirus replication. Inflammation may nevertheless alter their numbers or activity. In human organoids, interferon-gamma increases BEST4⁺ cell differentiation through a SPIB-dependent mechanism, and the resulting cells show stronger CFTR-dependent secretion after toxin exposure. If antiviral inflammation produces a similar response in living intestine, it could amplify fluid loss during acute disease. Conversely, bicarbonate secretion and mucus hydration might aid barrier repair during recovery. The review also connects BEST4⁺ cells to inflammatory bowel disease, where their abundance and expression of transport and metal-buffering genes appear altered, and to cystic fibrosis, in which defective CFTR trafficking may leave these high-CFTR cells unable to regulate anion transport, luminal acidity and mucus hydration.

These possibilities make BEST4⁺ cells attractive but challenging therapeutic targets. A drug that blocks pathological GUCY2C or CFTR activation could reduce fluid loss, yet permanent or systemic inhibition might undermine normal mucosal defense. Experimental CFTR inhibitors have reduced toxin-induced secretion in rodents, although some show limited solubility, rapid washout, narrow dosing windows or off-target effects on mitochondria. A more selective strategy may involve ADRA2A, an adrenergic receptor enriched in human BEST4⁺ cells; activating it suppresses cyclic AMP secretion and reverses cholera-toxin-induced swelling in enriched organoids. Such findings remain preclinical. The next steps will require lineage-specific genetic tools, direct electrophysiological measurements and disease experiments in animals that actually possess a conserved BEST4⁺ population. Conventional laboratory mice lack a canonical intestinal Best4 lineage, making rats, pigs, zebrafish and human organoids complementary rather than interchangeable models. Until researchers can manipulate these cells in vivo, BEST4⁺ cells should be viewed not as a confirmed master switch for viral diarrhea, but as a promising framework for understanding how infection, inflammation and epithelial ion transport converge.

At the molecular level, the proposed hub function depends on the way several transport systems are colocated rather than on BEST4 alone. Bestrophin channels are described as pentameric calcium-sensitive anion channels with a calcium-binding region, a hydrophobic gate and a cytoplasmic regulatory segment. This architecture provides a potential link between intracellular calcium signals and rapid changes in chloride or bicarbonate permeability. In a BEST4⁺ cell, such calcium-dependent conductance could complement CFTR, whose activity is controlled primarily through cyclic-nucleotide signaling. The two routes therefore offer distinct but potentially convergent means of regulating apical anion movement, while OTOP2 and CA7 could help couple that transport activity to the chemical conditions at the epithelial surface.

That arrangement also helps explain why anatomical location matters. BEST4⁺ cells are reported in the proximal small intestine and at the colonic surface, but their associated transport programs are not identical in every region or species. Villus-associated small-intestinal cells encounter different nutrient, acid and fluid gradients from cells near colonic crypt openings. Cross-species conservation supports a shared cellular program, yet conservation of marker genes does not establish conservation of net ion flux. Differences in epithelial architecture, microbiota, mucus organization and channel abundance could alter the physiological contribution of the same transcriptional cell type. Functional comparisons will therefore need to measure transport in defined regions rather than treating all BEST4⁺ cells as equivalent.

A central experimental challenge is separating correlation from cell-specific causation. High BEST4, GUCY2C or CFTR expression identifies a candidate effector population, but whole-organoid swelling, tissue short-circuit current and bulk transporter measurements integrate responses from many epithelial cells. Stronger tests would combine selective deletion or activation of BEST4⁺ cells with live measurements of intracellular pH, calcium, cyclic GMP, bicarbonate flux and mucus expansion. These experiments could determine whether BEST4 itself is the principal anion pathway, whether it mainly amplifies CFTR-mediated secretion, or whether its greatest contribution is sensing and coordinating responses among neighboring cells. They could also clarify whether toxin-induced secretion requires the endogenous guanylin–uroguanylin circuit or is driven predominantly by pharmacological stimulation of GUCY2C.

Therapeutic development will depend on preserving the distinction between pathological hypersecretion and protective basal transport. GUCY2C signaling and bicarbonate movement may contribute to epithelial maintenance and mucus function even while excessive cyclic GMP or cyclic AMP drives diarrhea. This argues for approaches that limit abnormal signal amplitude, duration or cellular targeting instead of eliminating the pathway entirely. Cell-type-resolved physiology, supported by species with a conserved BEST4⁺ population, should help identify that therapeutic window and establish whether the proposed hub is a druggable controller or primarily a useful map of interacting intestinal transport mechanisms.

Subject of Research: BEST4⁺ intestinal epithelial cells and their role in ion transport and diarrheal mechanisms

Article Title: BEST4⁺ cells: a potential hub of intestinal ion transport and diarrhea manipulation

Article References: Qu, H.-Z., & Wang, X.-Q. (2026). BEST4⁺ cells: a potential hub of intestinal ion transport and diarrhea manipulation. Advanced Biotechnology, 4(3), Article 33. https://doi.org/10.1007/s44307-026-00126-7

Image Credits: AI Generated

DOI: 10.1007/s44307-026-00126-7

Keywords: BEST4⁺ cells, intestinal epithelium, ion transport, CFTR, GC-C signaling, secretory diarrhea, viral gastroenteritis, mucus barrier, BEST4, cells, potential, intestinal