Fast dentification of overlapping fluorescence spectra of oil species based on LDA and two-dimensional convolutional neural network.

Although most petroleum oil species can be identified by their fluorescence spectra, overlapping fluorescence spectra make identification difficult. This study aims to address the issue that fluorescence spectroscopy is ineffective in identifying overlapping oil species. In this study, an equivalent model of overlapping oil species with fluorescence spectra was established. The linear discriminant analysis (LDA)-assisted machine learning (ML) algorithms K nearest neighbor (KNN), decision tree (DT), and random forest (RF) improved the identification of fluorescent spectrally overlapping oil species for diesel-lubricant oils. The identification accuracies of two-dimensional convolutional neural network (2DCNN), LDA combined with the ML algorithms effectively all 100 %. Furthermore, Partial Least Squares Regression (PLSR) algorithm, Support Vector Regression (SVR) algorithm, DT regression algorithm, and RF regression algorithm were also used to identify the lubricant concentration in diesel-lubricant oils. The coefficient of determination of the DT was 1, and the root-mean-square error was 0, which identified the concentration of lubricant oils in them accurately and without error.

Cotransport of nanoplastics with nZnO in saturated porous media: From brackish water to seawater.

The ocean serves as a repository for various types of artificial nanoparticles. Nanoplastics (NPs) and nano zinc oxide (nZnO), which are frequently employed in personal care products and food packaging materials, are likely simultaneously released and eventually into the ocean with surface runoff. Therefore, their mutual influence and shared destiny in marine environment cannot be ignored. This study examined how nanomaterials interacted and transported through sea sand in various salinity conditions. Results showed that NPs remained dispersed in brine, while nZnO formed homoaggregates. In seawater of 35 practical salinity units (PSU), nZnO formed heteroaggregates with NPs, inhibiting NPs mobility and decreasing the recovered mass percentage (Meff) from 24.52% to 12.65%. In 3.5 PSU brackish water, nZnO did not significantly aggregate with NPs, and thus barely affected their mobility. However, NPs greatly enhanced nZnO transport with Meff increasing from 14.20% to 25.08%, attributed to the carrier effect of higher mobility NPs. Cotransport from brackish water to seawater was simulated in salinity change experiments and revealed a critical salinity threshold of 10.4 PSU, below which the mobility of NPs was not affected by coexisting nZnO and above which nZnO strongly inhibited NP transport. This study highlights the importance of considering the mutual influence and shared destiny of artificial nanoparticles in the marine environment and how their interaction and cotransport are dependent on changes in seawater salinity.

Sea buckthorn extract mitigates chronic obstructive pulmonary disease by suppression of ferroptosis via scavenging ROS and blocking p53/MAPK pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Sea buckthorn (Hippophae rhamnoides), a traditional Tibetan medicinal herb, exhibits protective effects against cardiovascular and respiratory diseases. Although Sea buckthorn extract (SBE) has been confirmed to alleviate airway inflammation in mice, its therapeutic effect and underlying mechanism on chronic obstructive pulmonary disease (COPD) requires further clarification. AIM OF THE STUDY: To elucidate the alleviative effect and molecular mechanism of SBE on lipopolysaccharides (LPS)/porcine pancreatic elastase (PPE)-induced COPD by blocking ferroptosis. METHODS: The anti-ferroptotic effects of SBE were evaluated in human BEAS-2B bronchial epithelial cells using CCK8, RT-qPCR, western blotting, and transmission electron microscopy. Transwell was employed to detect chemotaxis of neutrophils. COPD model was induced by intranasally administration of LPS/PPE in mice and measured by alterations of histopathology, inflammation, and ferroptosis. RNA-sequencing, western blotting, antioxidant examination, flow cytometry, DARTS, CETSA, and molecular docking were then used to investigate its anti-ferroptotic mechanisms. RESULTS: In vitro, SBE not only suppressed erastin- or RSL3-induced ferroptosis by suppressing lipid peroxides (LPOs) production and glutathione (GSH) depletion, but also suppressed ferroptosis-induced chemotactic migration of neutrophils via reducing mRNA expression of chemokines. In vivo, SBE ameliorated LPS/PPE-induced COPD phenotypes, and inhibited the generation of LPOs, cytokines, and chemokines. RNA-sequencing showed that p53 pathway and mitogen-activated protein kinases (MAPK) pathway were implicated in SBE-mediated anti-ferroptotic action. SBE repressed erastin- or LPS/PPE-induced overactivation of p53 and MAPK pathway, thereby decreasing expression of diamine acetyltransferase 1 (SAT1) and arachidonate 15-lipoxygenase (ALOX15), and increasing expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11). Mechanistically, erastin-induced elevation of reactive oxygen species (ROS) was reduced by SBE through directly scavenging free radicals, thereby contributing to its inhibition of p53 and MAPK pathways. CETSA, DARTS, and molecular docking further showed that ROS-generating enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) may be the target of SBE. Overexpression of NOX4 partially impaired the anti-ferroptotic activity of SBE. CONCLUSION: Our results demonstrated that SBE mitigated COPD by suppressing p53 and MAPK pro-ferroptosis pathways via directly scavenging ROS and blocking NOX4. These findings also supported the clinical application of Sea buckthorn in COPD therapy.

Comparative phytochemical, antioxidant, and hemostatic studies of fractions from raw and roasted sea buckthorn seeds in vitro.

Various seeds, including sea buckthorn (Hippophae rhamnoides L.) seeds, are sources of different bioactive compounds. They can show anti-inflammatory, hypoglycemic, anti-hyperlipidemic, antibacterial, antioxidant, or other biological properties in in vitro and in vivo models. Our preliminary in vitro results have demonstrated that the extracts from raw (no thermal processing) and roasted (thermally processed) sea buckthorn seeds have antioxidant potential and anticoagulant activity. However, it was unclear which compounds were responsible for these properties. Therefore, in continuation of our previous study, the extracts were fractionated by C18 chromatography. Phytochemical analysis of three fractions (a, b, and c) from raw sea buckthorn seeds and four fractions (d, e, f, and g) from roasted sea buckthorn seeds were performed. Several in vitro assays were also conducted to determine the antioxidant and procoagulant/anticoagulant potential of the fractions and two of their major constituents-isorhamnetin 3-O-ß-glucoside7-O-α-rhamnoside and serotonin. LC-MS analyses showed that serotonin is the dominant constituent of fractions c and f, which was tentatively identified on the basis of its HRMS and UV spectra. Moreover, fractions c and f, as well as b and e, contained different B-type proanthocyanidins. Fractions b and e consisted mainly of numerous glycosides of kaempferol, quercetin, and isorhamnetin. The results of oxidative stress assays (measurements of protein carbonylation, lipid peroxidation, and thiol groups oxidation) showed that out of all the tested fractions, fraction g (isolated from roasted seeds and containing mainly dihexoses, and serotonin) demonstrated the strongest antioxidant properties.

Review of machine learning methods for sea level change modeling and prediction.

Sea level change, a major consequence of climate change, presents significant threats to coastal regions and demands precise, timely forecasting for effective management and adaptation. This review assesses methodologies and approaches essential for developing robust machine learning (ML) models for predicting and forecasting sea level change (SLC). Key findings reveal that artificial neural networks (ANNs), especially deep learning models and their hybrid variants, outperform traditional regression and simpler ML techniques in short-term sea level anomaly prediction. Supervised learning approaches dominate the field, while semi-supervised methods excel in short-term projections. Simpler models, such as regressions and support vector machines perform better with sufficient training data, however, often exhibit lower accuracy in handling complex, non-linear scenarios. The selection of relevant input variables, such as atmospheric, oceanic, and geological factors, significantly influences model accuracy, and the balance between training and testing data is crucial for avoiding overfitting and underfitting. This review also clarifies the distinction between ML prediction and forecasting as used in the literature. The study recommends that future research should focus on integrating physics-based general circulation models (GCMs) with ML techniques and exploring innovative methodologies to improve regional long-term forecasting, which is critical for effective coastal management and resilience.

Evidence for seasonal migration by a cryptic top predator of the deep sea.

BACKGROUND: In ecosystems influenced by strong seasonal variation in insolation, the fitness of diverse taxa depends on seasonal movements to track resources along latitudinal or elevational gradients. Deep pelagic ecosystems, where sunlight is extremely limited, represent Earth's largest habitable space and yet ecosystem phenology and effective animal movement strategies in these systems are little understood. Sperm whales (Physeter macrocephalus) provide a valuable acoustic window into this world: the echolocation clicks they produce while foraging in the deep sea are the loudest known biological sounds on Earth and convey detailed information about their behavior. METHODS: We analyze seven years of continuous passive acoustic observations from the Central California Current System, using automated methods to identify both presence and demographic information from sperm whale echolocation clicks. By integrating empirical results with individual-level movement simulations, we test hypotheses about the movement strategies underlying sperm whales' long-distance movements in the Northeast Pacific. RESULTS: We detect foraging sperm whales of all demographic groups year-round in the Central California Current System, but also identify significant seasonality in frequency of presence. Among several previously hypothesized movement strategies for this population, empirical acoustic observations most closely match simulated results from a population undertaking a "seasonal resource-tracking migration", in which individuals move to track moderate seasonal-latitudinal variation in resource availability. DISCUSSION: Our findings provide evidence for seasonal movements in this cryptic top predator of the deep sea. We posit that these seasonal movements are likely driven by tracking of deep-sea resources, based on several lines of evidence: (1) seasonal-latitudinal patterns in foraging sperm whale detection across the Northeast Pacific; (2) lack of demographic variation in seasonality of presence; and (3) the match between simulations of seasonal resource-tracking migration and empirical results. We show that sperm whales likely track oceanographic seasonality in a manner similar to many surface ocean predators, but with dampened seasonal-latitudinal movement patterns. These findings shed light on the drivers of sperm whales' long-distance movements and the shrouded phenology of the deep-sea ecosystems in which they forage.

The importance of temporal scale in distribution modeling of migratory Caspian Kutum, Rutilus frisii.

The choice of temporal resolution has high importance in ecological modeling, which can greatly affect the identification of the main drivers of an organism's distribution, considering the spatiotemporal dynamism of environmental predictors as well as organisms' abundance. The present study aimed to identify the spatiotemporal distribution patterns of Caspian Kutum, Rutilus frisii, along the southern coast of the Caspian Sea, north of Iran, evaluating multiple temporal resolutions of data. The boosted regression trees (BRT) method was used to model fish catch distribution using a set of environmental predictors. Three temporal scales of data, including seasonal, sub-seasonal, and monthly time frames over the catch season (October-April), were considered in our modeling analyses. The monthly models, utilizing more detailed data scales, exhibited the highest potential in identifying the overall distribution patterns of the fish, compared to temporally-coarse BRT models. The best models were the BRTs fitted using data from March and April, which represented the final months of the catch season with the highest catch levels. In the monthly models, the main determinants of the Kutum's aggregation points were found to be dynamic variables including sea surface temperature, particulate organic and inorganic carbon, as opposed to static topographic parameters such as distance to river inlets. Seasonal and sub-seasonal models identified particulate inorganic matter and distance to river inlets as the predictors with the highest influence on fish distribution. The geographical distributions of fish biomass hotspots revealed the presence of a stable number of fish aggregation hotspot points along the eastern coast, while some cold-spot points were identified along the central and western coasts of the Caspian Sea. Our findings indicate that utilizing fine time scales in modeling analyses can result in a more reliable explanation and prediction of fish distribution dynamics. The investigated approach allows for the identification of intra-seasonal fluctuations in environmental conditions, particularly dynamic parameters, and their relationship with fish aggregation.

Quality analysis and assessment of representative sea buckthorn fruits in northern China.

Sea buckthorn (SB) primarily grows in northern China and is rich in nutritional components, making it popular among consumers. This study aims to select suitable SB varieties for processing by analyzing physicochemical components, color, taste, and volatile compounds. The results showed that the physicochemical content of Chinese SB from Gansu were as follows: total soluble solids 13.50 ± 0.37°Brix, titratable acidity 6.46 ± 0.39 %, ascorbic acid 578 mg/100 g, polyphenols 517 mg/100 g, and flavonoids 194 mg/100 g, which were higher than those of the other four SB samples; the content of organic acids was relatively abundant. Taste analysis via electronic tongue indicated that Chinese SB had the highest ANS (sweetness) value and the lowest SCS (bitterness) value, exhibiting the richest flavor. Gas chromatography-mass spectrometry analysis showed that Gansu Chinese SB had a rich variety of volatile components, totaling 74. In summary, Gansu Chinese SB is a variety suitable for processing.

Seasonal variation in the stomach microbiota of two sympatrically breeding Pygoscelis penguin species at Signy Island, South Orkney Islands.

The gut microbiomes of Antarctic penguins are important for the fitness of the host birds and their chicks. The compositions of microbial communities in Antarctic penguin guts are strongly associated with the birds' diet, physiological adaptation and phylogeny. Whilst seasonal changes in food resources, distribution and population parameters of Antarctic penguins have been well addressed, little research is available on the stability or variability of penguin stomach microbiomes over time. Here, we focused on two Pygoscelis penguin species breeding sympatrically in the maritime Antarctic and analysed their stomach contents to assess whether penguin gut microbiota differed over three austral summer breeding seasons. We used a high-throughput DNA sequencing approach to study bacterial diversity in stomach regurgitates of Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis antarctica) penguins that have a similar foraging regime on Signy Island (South Orkney Islands). Our data revealed significant differences in bacterial alpha and beta diversity between the study seasons. We also identified bacterial genera that were significantly associated with specific breeding seasons, diet compositions, chick-rearing stages and sampling events. This study provides a baseline for establishing future monitoring of penguin gut microbiomes in a rapidly changing environment.

Retrospective comparison of thyroid hormones in Steller sea lions Eumetopias jubatus under professional care with and without thyroid disease.

An evaluation of morbidity and mortality in Steller sea lions (SSLs) Eumetopias jubatus under professional care identified a high prevalence of thyroid disease in aged animals. While studies have investigated the effects of age, season, nutrition, stressors, and pollutants on thyroid hormones in pinnipeds, data from individuals with known thyroid disease are lacking. Histopathological reports of adult SSLs in North American aquariums from 1979 to 2022 with banked serum (n = 14) were reviewed. Radioimmunoassays, which have been validated in this species, were used to determine triiodothyronine (TT3), total thyroxine (TT4), and free thyroxine (fT4). A solid-phase chemiluminescent immunometric assay for thyroid-stimulating hormone (TSH) quantification was validated by testing inter- and intra-assay repeatability, recovery, and parallelism. Lesions included follicular cysts (n = 5), adenoma with thyroglossal duct or follicular cysts (n = 2), medullary or follicular C-cell carcinoma with follicular cysts and nodular hyperplasia (n = 1), neuroendocrine carcinoma with follicular cysts (n = 1), and sarcomatoid carcinoma metastasis to the thyroid (n = 1). Significantly lower concentrations of TT3, TT4, and fT4 in SSLs with thyroid disease (n = 10) versus those without (n = 4) were attributed to space-occupying lesions, advanced age, and/or season. TSH was not significantly different between groups. Fifty percent of diseased SSL profiles were within reference ranges, and all individuals with lesions were clinically euthyroid. These data expand the current understanding of thyroid disease in SSLs and underscore the need for additional diagnostics (e.g. cervical ultrasound) concurrently with hormone assays to effectively screen for underlying abnormalities.

Synovial fluid analysis in healthy green turtles Chelonia mydas in Taiwan.

Septic arthritis is a frustrating disease in sea turtle rehabilitation because of its unclear pathogenesis, delayed onset during rehabilitation, long-term treatment requirements, and potentially poor prognosis. Radiography, blood cultures, and arthrocentesis have been used as diagnostic tools for suspected cases. However, there is currently a lack of data on the characteristics of synovial fluid in healthy sea turtles. To establish reference data for synovial fluid in sea turtles, we enrolled 14 green turtles Chelonia mydas rescued between 2019 and 2022 from 3 facilities using the following inclusion criteria: normal attitude and appetite, normal motor functions of the 4 limbs, no joint swelling, and no ongoing use of antibiotics for at least 1 mo. Bacterial cultures of blood and synovial fluid from the shoulder joints of these turtles were obtained and a qualitative analysis of the synovial fluid was performed. The results revealed bacterial culture-negative blood and synovial fluids at 37°C. Most characteristics of normal synovial fluid in green turtles, such as being transparent, colorless, and able to create a strand of over 2.5 cm by being pulled with a needle in viscosity trials, as well as the cytology of the normal synovial fluids being dominated by histiocytes and synovial lining cells, lymphocytes, and occasionally a few heterophils or erythrocytes were similar to those in mammals. This study provides information on the normal synovial fluid characteristics of green turtles in Taiwan, which may be beneficial for the diagnosis of joint diseases in sea turtles.

Regulation of Ocean Surface Currents and Seasonal Sea Ice Variations on the Occurrence and Transport of Organophosphate Esters in the Central Arctic Ocean.

Organophosphate esters (OPEs) have been observed in the remote Arctic Ocean, yet the influence of hydrodynamics and seasonal sea ice variations on the occurrence and transport of waterborne OPEs remains unclear. This study comprehensively examines OPEs in surface seawater of the central Arctic Ocean during the summer of 2020, integrating surface ocean current and sea ice concentration data. The results confirm significant spatiotemporal variations of the OPEs, with the total concentration of seven major OPEs averaging 780 ± 970 pg/L. Chlorinated OPEs, particularly tris(1-chloro-2-propyl) phosphate (TCPP), were dominant. The significant impact of hydrodynamics on the OPE transport is demonstrated by higher OPE concentrations in regions with strong surface currents, especially at the edge of the Beaufort Gyre and the confluence of the Beaufort Gyre and the Transpolar Drift. Furthermore, OPE levels were generally higher in drifting-ice-covered regions compared to ice-free regions, attributed to the volatilization of dissolved OPEs formerly trapped below the sea ice or newly released from melting snow and sea ice. Notably, TCPP decreased by only 19% in the ice-free area, while the more volatile triphenyl phosphate decreased by 63% compared with the partial ice region.

Screening and heterologous expression of an antimicrobial peptide SCAK33 with broad-spectrum antimicrobial activity resourced from sea cucumber proteome.

Antimicrobial peptides (AMPs) are a family of short defense proteins that are naturally produced by all organisms and have great potential as effective substitutes for small-molecule antibiotics. The present study aims to excavate AMPs from sea cucumbers and achieve their heterologous expression in prokaryotic Escherichia coli. Using MytC as a probe, a cysteine-stabilized peptide SCAK33 with broad-spectrum antimicrobial activity was discovered from the proteome of Apostichopus japonicas. The SCAK33 showed inhibitory effects on both gram positive and gram negative bacteria with MICs of 3-28 µM, and without significant hemolysis activity in rat blood erythrocyte. Especially, it exhibited good antimicrobial activity against Bacillus megaterium, B. subtilis, and Vibrio parahaemolyticus with the MIC of 3, 7, and 7 µM, respectively. After observation by scanning electronic microscopy (SEM) and confocal laser scanning microscope (CLSM), it was found that the cell membrane of bacteria was severely damaged. Furthermore, the recombinant SCAK33 (reSCAK33) was heterologously expressed by fusion with SUMO tag in E. coli BL21(DE3), and the protein yield reached 70 mg/L. The research will supplement the existing quantity of sea cucumber AMPs and provide data support for rapid mining and biological preparation of sea cucumber AMPs.

Assessment of anthropogenic particles in Holothuria sanctori from Tenerife (Canary Islands, Spain).

Sea cucumbers play a key role in maintaining the health of coastal marine ecosystems. The aim of this research was to evaluate the presence of anthropogenic particles in sea cucumbers of the species Holothuria sanctori in intertidal pools from Tenerife (Canary Islands, Spain) and in the surrounding seawater. In the case of sea cucumbers (n = 18), the gastrointestinal tract (particles ingested directly from the sediment) and Cuvierian tubules (particles presence as a result of gas exchange with seawater) were analysed separately. Anthropogenic particles were found in all samples, with an average concentration of 20.0 ± 4.4 items per litre in seawater and 11.8 ± 3.9 items per individual in the sea cucumbers, with a higher concentration of particles in the gastrointestinal tract (9.3 ± 3.4 items per gastrointestinal tract) than in the Cuvierian tubules (2.6 ± 3.3 items per Cuvierian tubules). Transparent and blue microfibres were predominant, accounting for over 90 % of the samples analysed. A significant proportion of these fibres were of cellulosic origin (either natural or semisynthetic, comprising 78.7 %), while fully synthetic polymers (microplastics), were also identified, including polyester and polyvinyl chloride (the latter exclusively detected in seawater).

Release of intracellular enzymes increases the total extracellular activities of carbohydrate processing enzymes in marine environment.

Microbial extracellular enzymatic activities (EEAs) produced by microbes to degrade biopolymers are the 'gatekeeper' of carbon cycle in the marine ecosystem. It is usually assumed that these extracellular enzymes are actively secreted by microbes. But biopolymers degrading enzymes also exist in the intracellular space. Cell lysis will passively release these enzymes into the environments and contribute to the total EEAs. However, to what extent the cell lysis can contribute to the total EEAs are still unclear. Here, using extreme cell lysis method, we evaluated the maximum contribution of cell lysis to total EEAs in culturable marine bacteria and coastal seawater. For carbohydrate processing enzymes (ß-glucosidase, alginate lyase and chitinase), the release of intracellular enzymes could contribute positively (up to 56.1% increase for ß-glucosidase in seawater) to the total EEAs. For protease and leucine aminopeptidase, the cell lysis did not increase and even decreased the total EEAs. For alkaline phosphatase, the intracellular enzymes generally had no contribution to the total EEAs. These results showed that passively released intracellular enzymes could substantially increase the total extracellular activities of carbohydrate processing enzymes, which should be considered in building the link between the EEAs and organic carbon cycle in the ocean.

Bleached coral supports high diversity and heterogeneity of bacterial communities: Following the rule of the 'Anna Karenina principle'.

Coral-associated bacteria are sensitive to the health status of coral and proven biomarker(s) of the coral bleaching. However, whether coral specificity or health status play a key role when coral-associated bacteria responding to coral bleaching is not known. Therefore, the bacterial communities of five species of healthy and bleached corals, Acropora millepora, Favites abdita, Galaxea fascicularis, Dipsastraea speciosa and Pocillopora damicornis, were collected along the coast of Sanya, South China Sea and targeted for associated bacterial studies. The relative abundance of the dominant class Gammaproteobacteria tended to be higher in healthy corals, while Alphaproteobacteria were more abundant in bleached corals. Dominant genus Achromobacter demonstrated higher relative abundance in healthy corals (0.675) than in bleached corals (0.151). Most of the bleached corals had high α diversity, ß dispersion, heterogeneity and complexity of the co-occurrence network of bacterial communities, which support the 'Anna Karenina Principle (AKP)' of diverse in threatened objects and conserved in healthy ones. The bacterial communities in the bleached corals were mostly involved in the selection process, and communities in the healthy corals were involved in the undominated process, which is obtained based on the null model test of ß nearest-taxon-index (ßNTI) and Bray-Curtis-based Raup-Crick (RCBray). This evidence further confirmed the AKP and revealed that the bacterial communities in the bleached corals were driven by deterministic factors. These findings provide valuable insights into the connection between bacterial and coral status, and the application of the AKP in the changing patterns of bacterial communities during coral bleaching.

Occurrence of microplastics in the gastrointestinal tracts of four most consumed fish species in Giresun, the Southeastern Black Sea.

Microplastic studies investigating concentrations in water are numerous, but the majority of microplastics settle and are retained in sediment, and higher concentrations are regularly reported in sediments. Thus, MPs accumulation may be more threatening to benthic fish living in sediments than to pelagic fish. The presence, abundance and diversity of microplastics were investigated by collecting samples from two pelagic, European anchovy, and horse mackerel and two benthic fish species, red mullet, and whiting that are popularly consumed in Giresun province of Türkiye, located on the southern coast of the Black Sea. Visual classification and chemical compositions of microplastics was performed using a light microscope and ATR-FTIR spectrophotometry, consecutively. The overall incidence and mean microplastics abundance in sampled fishes were 17 and 1.7 ± 0.18 MP fish-1, respectively. MPs were within the range of 0.026-5 mm in size. In most of the cases, the MP was black in color with 41%. With the rates of 56%, polypropylene was the predominant polymer type. The most dominant MP type was identified as fiber followed by fragments and pellets. The relationship between MP amounts in fish and Fulton condition factor was not strong enough to establish a cause-effect relationship.

The Effect of Synthetic Polyamine BPA-C8 on the Fertilization Process of Intact and Denuded Sea Urchin Eggs.

Sea urchin eggs are covered with layers of extracellular matrix, namely, the vitelline layer (VL) and jelly coat (JC). It has been shown that sea urchin eggs' JC components serve as chemoattractants or ligands for the receptor on the fertilizing sperm to promote the acrosome reaction. Moreover, the egg's VL provides receptors for conspecific sperm to bind, and, to date, at least two sperm receptors have been identified on the surface of sea urchin eggs. Interestingly, however, according to our previous work, denuded sea urchin eggs devoid of the JC and VL do not fail to become fertilized by sperm. Instead, they are bound and penetratedby multiple sperm, raising the possibility that an alternative pathway independent of the VL-residing sperm receptor may be at work. In this research, we studied the roles of the JC and VL using intact and denuded eggs and the synthetic polyamine BPA-C8. BPA-C8 is known to bind to the negatively charged macromolecular complexes in the cells, such as the JC, VL, and the plasma membrane of echinoderm eggs, as well as to the actin filaments in fibroblasts. Our results showed that, when added to seawater, BPA-C8 significantly repressed the Ca2+ wave in the intact P. lividus eggs at fertilization. In eggs deprived of the VL and JC, BPA-C8 binds to the plasma membrane and increases fibrous structures connecting microvilli, thereby allowing the denuded eggs to revert towards monospermy at fertilization. However, the reduced Ca2+ signal in denuded eggs was nullified compared to the intact eggs because removing the JC and VL already decreased the Ca2+ wave. BPA-C8 does not cross the VL and the cell membrane of unfertilized sea urchin eggs to diffuse into the cytoplasm at variance with the fibroblasts. Indeed, the jasplakinolide-induced polymerization of subplasmalemmal actin filaments was inhibited in the eggs microinjected with BPA-C8, but not in the ones bath-incubated with the same dose of BPA-C8.

Preventing illegal seafood trade using machine-learning assisted microbiome analysis.

BACKGROUND: Seafood is increasingly traded worldwide, but its supply chain is particularly prone to frauds. To increase consumer confidence, prevent illegal trade, and provide independent validation for eco-labelling, accurate tools for seafood traceability are needed. Here we show that the use of microbiome profiling (MP) coupled with machine learning (ML) allows precise tracing the origin of Manila clams harvested in areas separated by small geographic distances. The study was designed to represent a real-world scenario. Clams were collected in different seasons across the most important production area in Europe (lagoons along the northern Adriatic coast) to cover the known seasonal variation in microbiome composition for the species. DNA extracted from samples underwent the same depuration process as commercial products (i.e. at least 12 h in open flow systems). RESULTS: Machine learning-based analysis of microbiome profiles was carried out using two completely independent sets of data (collected at the same locations but in different years), one for training the algorithm, and the other for testing its accuracy and assessing the temporal stability signal. Briefly, gills (GI) and digestive gland (DG) of clams were collected in summer and winter over two different years (i.e. from 2018 to 2020) in one banned area and four farming sites. 16S DNA metabarcoding was performed on clam tissues and the obtained amplicon sequence variants (ASVs) table was used as input for ML MP. The best-predicting performances were obtained using the combined information of GI and DG (consensus analysis), showing a Cohen K-score > 0.95 when the target was the classification of samples collected from the banned area and those harvested at farming sites. Classification of the four different farming areas showed slightly lower accuracy with a 0.76 score. CONCLUSIONS: We show here that MP coupled with ML is an effective tool to trace the origin of shellfish products. The tool is extremely robust against seasonal and inter-annual variability, as well as product depuration, and is ready for implementation in routine assessment to prevent the trade of illegally harvested or mislabeled shellfish.

Generation of Novel Tumour-Selective SEA Superantigen-Based Peptides with Improved Safety and Efficacy for Precision Cancer Immunotherapy.

Bacterial superantigens are T-cell-stimulatory protein molecules which produce massive cytokines and cause human diseases. Due to their ability to activate up to 20% of resting T-cells, they have effectively killed T-cell-dependent tumours in vivo. However, the intrinsic toxicity of whole SAg molecules highlights the urgent need to develop more effective and safer SAg-based immunotherapy. With its unique approach, our study is a significant step towards developing safer tumour-targeted superantigen peptides (TTSP). We identified the T-cell activation function regions on the SEA superantigen and produced variants with minimal lethality, ensuring a safer approach to cancer treatment. This involved the creation of twenty 50-amino-acid-long overlapping peptides covering the full-length SEA superantigen (P1-P20). We then screened these peptides for T-cell activation, successfully isolating two peptides (P5 and P15) with significant T-cell activation. These selected peptides were used to design and synthesise tumour-targeted superantigen peptides, which were linked to a cancer-specific third loop (L3) of transforming growth factor-α (TGF-α), TGFαL3 from either a C' or N' terminal with an eight-amino-acid flexible linker in between. We also produced several P15 variants by changing single amino acids or by amino acid deletions. The novel molecules were then investigated for cytokine production and tumour-targeted killing. The findings from our previous study and the current work open up new avenues for peptide-based immunotherapy, particularly when combined with other immunotherapy techniques, thereby ensuring effective and safer cancer treatment.