The research, published in the journal PLOS ONE on 18 September 2026, describes a hybrid antifouling material that combines two distinct strategies operating at different length scales. The team fabricated coatings of zinc oxide nanorods on three differently patterned polymer surfaces, labeled D1, D2, and D3 in the study. Each polymer substrate carried its own microscale texture, and the zinc oxide nanorods added a second, nanoscale layer of structure on top. This hierarchical architecture, in which micro- and nanostructured features coexist on a single surface, is central to the design philosophy. In nature, many organisms deter fouling not through chemical warfare alone but through precisely sculpted surface topographies, and the Omani team sought to mimic and enhance this principle with a functional semiconductor material known for its antimicrobial properties.

Zinc oxide has attracted considerable attention in materials science because it combines several useful characteristics in a single compound. It is a wide-bandgap semiconductor, it can be grown into elongated nanorod crystals with high surface area under relatively mild laboratory conditions, and it exhibits antibacterial activity through well-documented mechanisms. When zinc oxide nanostructures interact with water, they can release zinc ions, which are toxic to many microorganisms at sufficient concentrations. They can also generate reactive oxygen species, chemically aggressive molecules that damage cell membranes, proteins, and DNA. By growing dense forests of these nanorods directly onto textured polymer surfaces, the researchers created materials in which both the physical topography and the chemical activity of the coating could contribute to fouling resistance simultaneously.

To evaluate how well the hybrid surfaces performed, the team subjected them to laboratory tests under flow conditions, an important detail because real marine equipment rarely sits in stagnant water. Flow alters how microorganisms approach, contact, and adhere to surfaces, so testing under flowing conditions provides a more realistic assessment than simple static immersion. Two representative fouling organisms were chosen: the bacterium Escherichia coli, a widely used model organism in antibacterial testing, and Amphora sp., a marine diatom. Diatoms are single-celled algae with silica shells and are among the earliest and most problematic colonizers of submerged surfaces, forming slimy biofilms that pave the way for larger fouling organisms. The researchers also assessed the acute toxicity of the coated surfaces using larvae of the whiteleg shrimp, Litopenaeus vannamei, a commercially important aquaculture species whose sensitivity makes it a useful indicator of environmental risk.

One of the most striking physical changes induced by the nanorod coating was a dramatic shift in wettability. The uncoated patterned polymer surfaces exhibited water contact angles of roughly 80 to 90 degrees, values typical of moderately wettable materials that water spreads across fairly readily. After the zinc oxide nanorods were applied, the contact angles climbed to approximately 150 to 165 degrees, placing the surfaces in the range considered highly water-repellent or superhydrophobic. At such angles, water droplets bead up and roll off easily, sitting atop the textured surface rather than wetting it. This behavior matters for antifouling because many marine organisms need a hydrated interface to attach successfully, and surfaces that resist wetting can present a formidable first barrier to colonization.

The biological results revealed a nuanced picture in which the underlying micropattern proved just as important as the coating itself. Bacterial attachment was reduced by 60.3 percent on the coated D1 surface, by 48.8 percent on coated D2, and by only 5.8 percent on coated D3. The diatom results followed a different pattern: coverage fell by 9.9 percent on coated D1 but by 72.9 percent on coated D2 and 71.8 percent on coated D3. In other words, the surface that best suppressed bacteria was not the one that best suppressed diatoms, and the surface with the weakest antibacterial effect still performed admirably against algal settlement. This divergence underscores a key insight of the study: antifouling performance is not a simple function of the coating material but emerges from the interplay between the nanorods and the specific geometry of the micropattern beneath them.

The researchers attributed the observed antifouling effects to a combination of mechanisms acting in concert. The release of zinc ions and the generation of reactive oxygen species provide direct chemical pressure against attached microorganisms. Surface wettability alters the initial interaction between organism and substrate, making adhesion energetically less favorable. Finally, the interaction between the microscale polymer patterns and the nanoscale zinc oxide structures shapes how cells encounter and contact the surface at the micrometer scale, influencing whether they can establish stable attachment. Because each mechanism operates differently against different organisms, the balance among them determines the overall antifouling profile of a given surface design, which helps explain why the three patterns produced such distinct results.

Toxicity findings added a further layer of complexity to the design question. The zinc oxide-coated D1 surface showed the best overall balance between antifouling performance and low toxicity toward shrimp larvae, making it the most environmentally promising of the three designs. The coated D3 surface, by contrast, combined lower antibacterial performance with greater larval toxicity, an unfavorable pairing that illustrates why simply applying an antimicrobial nanocoating is not sufficient. The geometry of the underlying pattern can amplify or dampen both the beneficial and the harmful effects of the nanomaterial. For any future application, the study suggests, engineers must treat the surface pattern and the coating as a single integrated design problem rather than optimizing them independently.

Durability is another critical consideration for any material intended for marine service, and here the study offered encouraging preliminary evidence. Microscopic examination conducted after the biological experiments showed that the zinc oxide nanorods remained structurally intact, indicating that the coatings withstood the laboratory testing period without significant physical degradation. Coatings that shed nanoparticles or crumble under flow would pose both a performance problem and an environmental one, releasing engineered material into the water column. The structural stability observed in this work suggests that the nanorods were well anchored to their polymer substrates, although the researchers were careful to note that their experiments were conducted under controlled laboratory conditions rather than in the open ocean.

The path from laboratory promise to practical deployment remains a long one, and the authors were explicit about the limitations of the current work. Long-term field trials and further ecotoxicological assessments will be required before these coatings can be considered for real marine or industrial use. Seawater is a far more chemically complex and biologically diverse environment than any laboratory assay, and months or years of exposure introduce degradation pressures, seasonal variation in fouling communities, and ecological interactions that short-term tests cannot capture. Nevertheless, the findings point toward a promising direction: combining zinc oxide nanorods with deliberately designed micropatterned surfaces could eventually support antifouling applications on ship surfaces, aquaculture nets, water-intake systems, and other equipment exposed to marine environments. If subsequent trials confirm the laboratory results, such materials could offer a route to fouling control that reduces reliance on toxic chemical leaching, aligning with the growing regulatory and environmental pressure to make antifouling technology safer for the oceans it operates in.

Subject of Research: Antifouling performance of zinc oxide nanorod coatings on micropatterned polymer surfaces against marine microorganisms

Article Title: Can nanostructured surfaces help keep marine equipment clean?

Article References: Can nanostructured surfaces help keep marine equipment clean?. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: biofouling, zinc oxide nanorods, micropatterned polymers, antifouling coatings, marine science, Escherichia coli, Amphora diatom, superhydrophobic surfaces, reactive oxygen species, Litopenaeus vannamei, ecotoxicology, Sultan Qaboos University

When the surrounding water dilutes, a shrimp’s cells face a triple assault. Osmotic stress makes cells swell as water rushes in, disrupting the delicate water balance inside tissues. Ionic stress impairs the channels and enzymes that keep sodium, potassium and chloride in check. And oxidative stress generates reactive oxygen species that oxidize proteins, inactivate enzymes and damage DNA. Together, these pressures can trigger apoptosis, alter membrane fluidity and ultimately kill the animal. Understanding how shrimp blunt this cascade is not just an academic exercise; it directly determines survival, growth and productivity on farms that supply a large share of the world’s seafood protein.

The review’s first major theme is how shrimp perceive salinity change in the first place. G protein-coupled receptors, or GPCRs, are abundant in penaeid genomes: the L. vannamei reference genome contains 457 GPCR genes, and transcriptome curation in P. monodon identified three major classes totaling 350 members. Intriguingly, the authors caution that direct evidence for GPCRs acting as primary salinity sensors remains limited. Instead, these receptors are more plausibly engaged indirectly, as salinity shifts alter the availability of neuroendocrine and paracrine ligands. Once activated, GPCRs funnel signals through cAMP, protein kinase A, PI3K-Akt and MAPK cascades. Transcriptomic profiling of P. monodon gills under chronic low salinity showed differentially expressed genes mapping to PI3K-Akt, MAPK and calcium signaling pathways, supporting a role for GPCR-linked cascades in gill-centered osmoregulatory acclimation.

Calcium signaling emerges as a second, faster perception module. As extracellular osmotic pressure drops, calcium-permeable membrane channels open and calcium is also mobilized from intracellular stores such as the endoplasmic reticulum, producing a transient spike in cytosolic calcium. In P. monodon, acute low-salt stress significantly enriches gene sets for calcium ion transmembrane transport, calmodulin binding and regulation of cytosolic calcium concentration, accompanied by increased activity of Ca2+/Mg2+-ATPase. The calcium wave activates a battery of calcium-sensitive kinases and phosphatases that fine-tune ion pumps through phosphorylation, restoring not only calcium balance but also sodium and potassium equilibrium. Strikingly, the cellular energy sensor AMPK rides along: hepatopancreatic AMPK-alpha transcripts increase roughly 28-fold just six hours after Pacific white shrimp are transferred from salinity 20 to salinity 3, linking osmotic calcium dynamics to metabolic reprogramming through calcium/calmodulin-dependent kinase kinase pathways.

The third perception layer is phospholipid signaling and membrane remodeling. Low salinity directly changes the physical state of cell membranes, particularly their fluidity and the activity of embedded proteins. Shrimp respond by adjusting membrane phospholipid composition, and over longer exposures they shift the ratio of saturated to unsaturated fatty acids to keep membranes supple. Phospholipase C-mediated hydrolysis of phosphoinositides generates second messengers such as IP3 and diacylglycerol, tuning membrane-protein interactions and the trafficking of ion-transport systems. The review frames this lipid turnover primarily as membrane remodeling that stabilizes integrity and preserves the function of osmoregulatory channels and pumps during cell swelling and volume recovery, a subtle but crucial distinction for interpreting the data.

Downstream of perception, three kinase networks translate stress signals into coordinated action. The MAPK pathway, with its ERK, JNK and p38 branches, governs cell growth, stress-responsive transcription and apoptosis; ERK supports proliferation while JNK and p38 can eliminate severely damaged cells and regulate inflammatory gene expression. The PI3K-Akt pathway acts as a survival engine: activated PI3K generates PIP3, which engages Akt, which in turn phosphorylates mTOR to promote anabolic metabolism while suppressing apoptotic proteins such as Bad and excluding FOXO transcription factors from the nucleus. Negative feedback through PTEN keeps the pathway from pathological overactivation. Meanwhile, the NF-kappaB pathway, engaged via I-kappa-B regulation and nuclear translocation, promotes immune, stress-response and anti-apoptotic gene programs. Together these modules drive gill-centered osmoregulation, immune priming and antioxidant control.

At the organ level, the gills take center stage. Gill ionocytes dynamically adjust ion absorption or excretion through core transport systems, most notably Na+/K+-ATPase and carbonic anhydrase. In dilute water, P. monodon ramps up ion uptake to raise internal osmotic pressure and prevent excessive water influx and cellular rupture. Na+/K+-ATPase burns ATP to exchange three sodium ions for two potassium ions across the membrane, maintaining the electrochemical gradient, and its activity typically rises under low salinity. Carbonic anhydrase catalyzes the reversible hydration of carbon dioxide, producing bicarbonate and protons that support the Na+/H+ exchanger and acid-base balance. Recent transcriptome work in P. monodon found markedly upregulated Na+/K+-ATPase subunits and elevated carbonic anhydrase transcripts under low salinity, alongside dynamic changes in actin and tubulin genes indicating cytoskeletal remodeling of gill epithelia. Antennal and maxillary glands contribute auxiliary water and ion excretion, though shrimp-specific mechanistic data for the latter remain thin.

The review also highlights two cellular quality-control systems that have received less attention. Autophagy, the degradation and recycling of damaged proteins and organelles, is initiated when energy stress activates AMPK and relieves mTOR-mediated inhibition of the Atg1 initiation complex. A cascade of Atg proteins, including the transmembrane Atg9 and the Atg7-Atg3 conjugation machinery that lipidates Atg8, builds autophagosomes that fuse with lysosomes to recycle cellular debris. In parallel, endoplasmic reticulum stress engages three sensor arms: PERK slows protein synthesis by phosphorylating eIF2-alpha while activating ATF4; ATF6 is cleaved in the Golgi to activate ER quality-control genes; and IRE1 splices XBP1 mRNA to boost chaperone and lipid biosynthesis. Proteins such as GRP78/BiP and CHOP decide whether the cell restores folding capacity or succumbs to apoptosis.

Salinity stress also reshapes immunity and redox balance. Under hyposalinity, shrimp upregulate scleroproteins that thicken the cuticle, lysozymes that dissolve bacterial cell walls, and antilipopolysaccharide factors that neutralize bacterial endotoxin. Recent transcriptomic data from P. monodon show that low salinity alone triggers upregulation of Toll-like receptor genes and downstream NF-kappaB components, suggesting osmotic stress primes innate immunity even without pathogens. Because immune effector processes and osmotic disturbance both elevate reactive oxygen species, antioxidant defense is tightly coupled to immune function. The Keap1-Nrf2 axis sits at the center: oxidative stress releases Nrf2 from Keap1, allowing it to enter the nucleus and bind antioxidant response elements, switching on superoxide dismutase, catalase, glutathione peroxidase and heme oxygenase-1, with feedback mechanisms preventing an overactive response.

The practical payoff is already visible in feeding trials. The review compiles nutritional interventions with direct experimental support for improved low-salinity resilience: cholesterol and phospholipids to stabilize membranes, vitamin C derivatives such as L-ascorbyl-2-polyphosphate to buffer oxidation, potassium and magnesium supplementation to enhance ion balance, and myo-inositol to support stress tolerance. Looking forward, the authors argue that identifying the true upstream osmosensors, integrating multi-omics with time-series designs, and exploiting chromosome-level genomes of L. vannamei, P. monodon and Marsupenaeus japonicus for comparative genomics and marker-assisted breeding will be essential. Genome editing remains technically difficult in crustaceans, so selective breeding and genomic selection carry near-term weight. As salinity fluctuations grow more frequent and less predictable, decoding the shrimp’s molecular playbook may prove decisive for building climate-resilient aquaculture systems.

Subject of Research: Molecular and physiological adaptations of penaeid shrimp to low-salinity stress

Article Title: Molecular and physiological adaptations to low-salinity stress in penaeid shrimp: a focus on Litopenaeus vannamei and Penaeus monodon

Article References: Huang, S., Zhou, F., Jiang, S., Li, E., & Li, Y. (2026). Molecular and physiological adaptations to low-salinity stress in penaeid shrimp: a focus on Litopenaeus vannamei and Penaeus monodon. Stress Biology, 6(1), Article 34. https://doi.org/10.1007/s44154-026-00295-4

Image Credits: AI Generated

DOI: 10.1007/s44154-026-00295-4

Keywords: penaeid shrimp, Litopenaeus vannamei, Penaeus monodon, low-salinity stress, osmoregulation, GPCR signaling, calcium signaling, Na+/K+-ATPase, autophagy, endoplasmic reticulum stress, Nrf2 antioxidant pathway, aquaculture

The research, led by Nor Jumanah Said Mohamed of Universiti Kebangsaan Malaysia together with colleagues including Ahmad Razi Othman, Siti Rozaimah Sheikh Abdullah and Nur ‘Izzati Ismail, with Clara Manno of the British Antarctic Survey and Mohd Yunus Abd Shukor of Universiti Putra Malaysia, focuses on chitosan, a biopolymer derived from chitin. Chitin is the structural material that gives crustacean shells their strength, and it is abundantly available as waste from the seafood industry. When chitin is deacetylated, meaning that acetyl groups are chemically removed from its long molecular chains, it becomes chitosan, a positively charged polymer that can bind negatively charged particles suspended in water and draw them into settleable clumps. That charge behaviour is precisely what makes chitosan attractive as a coagulant for microplastics, which tend to carry surface charges that keep them dispersed.

The catch lies in how chitosan is produced. Conventional extraction relies on strong acids and alkalis, processes that consume chemicals and energy and can themselves create environmental burdens that offset the benefits of using a bio-based coagulant. The Malaysian team therefore turned to deep eutectic solvents, or DESs, a family of designer solvents formed by mixing a hydrogen bond donor and a hydrogen bond acceptor, in this case all based on choline chloride. The resulting liquids have unusual solvation properties, low volatility and a reputation for being far gentler on the environment than traditional industrial solvents. Because their composition can be tuned by choosing different donor molecules, DESs offer chemists a kind of molecular dial for controlling extraction outcomes.

The researchers tested four choline chloride-based deep eutectic solvents, pairing the choline chloride with glycerol, malonic acid, glucose or urea. Each combination interacts differently with the mineral and protein components of shrimp shells, and the team wanted to know which would best liberate chitin and convert it toward chitosan. The winner was choline chloride combined with malonic acid, abbreviated CCMA. Shells of the whiteleg shrimp Litopenaeus vannamei, one of the most farmed shrimp species in the world and therefore a plentiful waste stream, treated with this solvent yielded 19.09 percent chitosan with a solubility of 90.68 percent, the best figures among the four solvents examined.

Characterisation confirmed that the extracted material was genuine chitosan with useful structural properties. Fourier transform infrared spectroscopy, which probes the chemical bonds in a sample, verified the functional groups expected of deacetylated chitin. X-ray diffraction revealed a semicrystalline structure, a balance of ordered and disordered regions that is typical of chitosan and relevant to how the polymer behaves in solution. Scanning electron microscopy added a striking visual detail: the DES-extracted chitosan displayed a porous, honeycomb-like morphology. Such an open architecture increases the surface area available for contact with suspended particles, a feature that plausibly supports the material’s performance as a coagulant.

Getting the most out of the extraction required careful optimisation. The team first used a one-variable-at-a-time approach, adjusting temperature, reaction time and the ratio of shrimp shell material to solvent individually, and then refined the process with response surface methodology, a statistical technique that maps how several variables interact simultaneously and locates the true optimum rather than a series of local improvements. The optimal conditions emerged as a temperature of 93.91 degrees Celsius, a reaction time of 8.15 hours and a shell-to-solvent ratio of 0.042 grams per millilitre, corresponding to 21 grams of shell per 500 millilitres of solvent. Under these conditions the chitosan reached a degree of deacetylation of 89.05 percent, and the statistical model describing the process showed a strong fit with an R-squared value of 0.9521, indicating that the chosen variables explain most of the variation in the outcome.

The degree of deacetylation matters enormously for coagulation. The more acetyl groups removed, the more free amino groups the polymer carries, and at acidic to neutral pH these amino groups become protonated, giving the chain its positive charge. A chitosan with nearly 90 percent deacetylation is therefore a highly charged molecule, well suited to neutralising the negative surface charges that keep microplastic particles suspended. Charge neutralisation and the subsequent bridging of particles by long polymer chains are the two principal mechanisms by which coagulants turn a cloudy suspension into settleable flocs.

With the optimised chitosan in hand, the team put it to the test against polyethylene, one of the most common plastics in the waste stream and a frequent component of microplastic pollution. In a controlled suspension of polyethylene microparticles in deionised water, the CCMA-derived chitosan achieved a maximum reduction of 58.10 percent in turbidity and 63.55 percent in total suspended solids at a dose of 50 milligrams per litre. Importantly, these figures were corrected against a no-coagulant control, ensuring that the measured removal reflected genuine coagulation rather than simple settling. The performance was comparable to that of commercial chitosan under the same conditions, a significant result for a material produced through a greener extraction route.

The authors are careful about the limits of their findings. The coagulation experiments were conducted in deionised water, a clean and simplified matrix that lacks the organic matter, salts and competing particles found in real wastewater. Natural waters can dramatically alter coagulation behaviour, since dissolved organic carbon competes for the polymer’s binding sites and ionic strength changes the electrostatic interactions at play. The study itself notes that further validation under representative wastewater conditions is required before the approach can be considered ready for practical deployment. That caveat is standard for laboratory-scale coagulation research, but it is an essential one for readers hoping to gauge how quickly this technology might reach treatment plants.

Even with those caveats, the study contributes a meaningful piece to the puzzle of sustainable microplastic remediation. It links two waste streams in a single solution: shrimp shells that would otherwise be discarded become a high-performance coagulant, and the solvent used to extract it is designed to be environmentally benign and potentially recoverable. It also demonstrates a rigorous workflow, from solvent screening through statistical optimisation to materials characterisation and application testing, that other groups can adapt to different feedstocks and different pollutant targets. As regulators and utilities worldwide grapple with how to remove microplastics from effluents and drinking water, approaches that avoid swapping one pollution problem for another will be increasingly valuable. This work suggests that the answer to a plastic problem might, in part, come from the seafood counter, provided the chemistry behind it stays as green as the ambition.

Subject of Research: Green extraction of chitosan from shrimp shell waste with deep eutectic solvents for microplastic coagulation

Article Title: Deep eutectic solvent-assisted extraction of chitosan for polyethylene microplastic coagulation

Article References: Mohamed, N. J. S., Othman, A. R., Manno, C., Shukor, M. Y. A., Abdullah, S. R. S., & Ismail, N. I. (2026). Deep eutectic solvent-assisted extraction of chitosan for polyethylene microplastic coagulation. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-026-38253-2

Image Credits: AI Generated

DOI: 10.1007/s11356-026-38253-2

Keywords: chitosan, deep eutectic solvents, microplastics, polyethylene, coagulation-flocculation, shrimp shell waste, chitin, degree of deacetylation, response surface methodology, water treatment, green chemistry, Litopenaeus vannamei

The stakes are considerable. Shrimp aquaculture supplies more than half of the global shrimp market, and L. vannamei alone accounts for roughly 80 percent of farmed shrimp output, thanks to its rapid growth and tolerance of salinities ranging from 0.5 to 40 parts per thousand. But the industry is chronically undermined by environmental stress. Rising ammonia in culture water impairs growth, invites disease, and kills animals; temperature swings disrupt hormones and enzymes, which function best between 28 and 32 degrees Celsius; and ammonia competes with oxygen for binding sites on the oxygen-carrying pigment haemocyanin, choking respiration and suppressing immunity. Biofloc technology promises a way out by converting toxic nitrogenous waste into microbial biomass that shrimp can themselves consume.

To understand what biofloc actually does inside the animal, the team first ran an optimization experiment using a Taguchi L9 orthogonal array and grey relational analysis, testing stocking densities of 100 to 300 shrimp per cubic meter, carbon-to-nitrogen ratios of 10 to 20, and probiotic doses of 7 to 21 milliliters per liter. Two winning configurations emerged as treatments for the main trial: GRG1, with 200 shrimp per cubic meter, a C/N ratio of 10:1, and 14 milliliters per liter of the probiotic Bacillus tropicus; and GRG2, with the same density but a C/N ratio of 20:1 and half the probiotic dose. Both were run inside the IMTAS facility, a closed-loop system combining shrimp culture, cyclone-based flocculation with UV treatment, and a phytoremediation unit where Caulerpa seaweed strips nutrients from recirculating water, all monitored through an Internet of Things control network.

The water chemistry alone told a compelling story. Over the twelve-week culture period, both biofloc treatments maintained significantly lower total ammonia nitrogen, nitrite, and phosphate than the control, which relied on a modest 2.5 percent daily water exchange and no microbial management. Dissolved oxygen was significantly higher in the biofloc tanks, as were pH levels, while conductivity, total dissolved solids, and salinity were all lower. In other words, the microbial flocs were doing precisely what biofloc advocates claim: assimilating inorganic nitrogen into microbial biomass and stabilizing the culture environment without external water input.

The shrimp responded in kind. Mean final weight climbed from 10.50 grams in the control to 21.45 grams in GRG1, more than a doubling. Specific growth rate rose from 3.96 to 4.79 percent per day, feed conversion ratio improved from 1.39 to 1.05, and survival jumped from 49.08 percent to 75.91 percent. GRG1 outperformed every other treatment on every metric measured, a phenotypic signal that the transcriptomic data would soon help explain.

For the molecular analysis, the researchers dissected midgut tissue at harvest, flash-froze it in liquid nitrogen, and sequenced RNA on an Illumina NovaSeq 6000, mapping 150-base-pair paired-end reads against the L. vannamei reference genome. Differential expression analysis with DESeq2, using strict thresholds of a log2 fold change of at least 1 and an adjusted p-value of 0.05 or below, revealed 1,245 differentially expressed genes in GRG1 versus the control, 1,145 in GRG2 versus the control, and 681 between the two biofloc treatments themselves. Hierarchical clustering and principal component analysis confirmed that both biofloc groups clustered apart from the control, with treatment-specific expression signatures. The smaller number of differences between GRG1 and GRG2 makes sense: both animals were living in biofloc, so their shared transcriptomic response dwarfed the differences between the two floc recipes.

The pathway-level results were the most revealing. In GRG1 versus the control, three KEGG pathways were significantly enriched: the proteasome, autophagy, and phagosome pathways. Proteasome subunits across both the 26S regulatory particles and the 20S core were strongly upregulated, indicating accelerated degradation of ubiquitinated and misfolded proteins and tighter cellular quality control. The autophagy pathway showed four-fold or greater upregulation of TSC1, AMPK, ULK1/2, LC3, ATG2, and ATG9L, pointing to vigorous autophagosome formation and cellular component recycling, while BNIP3, a hypoxia-responsive gene, rose 3.2-fold, suggesting improved tolerance of environmental stress. In the phagosome pathway, tubulin genes surged up to ten-fold, actin and integrins rose five-fold, and thrombospondin increased a remarkable 22-fold, together implying enhanced cytoskeletal dynamics, immune cell adhesion, and intracellular pathogen clearance.

GRG2 shrimp told a different molecular story. Their enriched pathways were aminoacyl-tRNA biosynthesis and protein processing in the endoplasmic reticulum, reflecting a shift in how protein was built rather than broken down. Alanyl-tRNA synthetase was upregulated, favoring alanine incorporation, while synthetases for glutamine, aspartate, and glycine were downregulated, hinting at selective modulation of amino acid use under the higher carbon-to-nitrogen regime. In the endoplasmic reticulum pathway, heat shock protein 70 rose four-fold and ER-associated degradation genes such as p97 and ufd1 climbed, while calnexin, BiP, and eIF2α fell, suggesting a reduced burden from the unfolded protein response. Comparing the two biofloc treatments directly, oxidative phosphorylation emerged as the distinguishing pathway: NADH dehydrogenase subunits were upregulated in GRG1, while cytochrome c oxidase subunits were downregulated, indicating treatment-specific differences in mitochondrial energy metabolism.

The convergence of molecular and phenotypic data is what gives the study its punch. GRG1, the treatment with the cleanest water and the strongest growth, was also the one with the greatest enrichment of protein turnover, immune, and energy pathways, suggesting that biofloc conditions triggered a systemic reprogramming that favored metabolic efficiency and resilience. Proteasome activity kept cellular proteins in order, autophagy recycled components under culture stress, and phagosome activation plausibly bolstered defense against pathogens, all of which created an internal environment conducive to the doubled weight gain and 76 percent survival observed. The authors are careful to frame the work as exploratory: the control group had only two usable RNA libraries after one degraded, physiological immune markers such as total hemocyte count and phenoloxidase activity were not measured, and the control’s different water exchange regime makes it hard to fully separate biofloc effects from water management effects. No qPCR validation was performed, so the expression patterns await independent confirmation.

Even with those caveats, the study delivers something the biofloc field has lacked: a tissue-specific, genome-wide account of what microbial flocs actually do to the animals farmed among them. With the sequencing data deposited in the NCBI Sequence Read Archive under BioProject PRJNA1468551, the researchers have laid a molecular foundation for optimizing biofloc protocols, potentially identifying gene expression markers that predict which floc configurations will produce the healthiest, fastest-growing shrimp. As global demand for shrimp keeps climbing and freshwater and coastal resources come under pressure, farming systems that let microbes do the water treatment, while the shrimp’s own genes do the rest, may prove to be one of aquaculture’s most important technological turns.

Subject of Research: Transcriptomic responses of Pacific white shrimp to biofloc technology in indoor aquaculture

Article Title: Transcriptomic adaptation of Litopenaeus vannamei to biofloc conditions in an indoor aquaculture system

Article References: Transcriptomic adaptation of Litopenaeus vannamei to biofloc conditions in an indoor aquaculture system. (n.d.). https://doi.org/10.1007/s44338-026-00257-0

Image Credits: AI Generated

DOI: 10.1007/s44338-026-00257-0

Keywords: biofloc technology, Litopenaeus vannamei, transcriptomics, aquaculture, gene expression, RNA sequencing, immune response, protein turnover, autophagy, phagosome, oxidative phosphorylation, water quality