Designing and applying a methodology to assess sperm cell viability and DNA damage in a model amphipod.

Sperm quality is defined as the sperm cell ability to successfully fertilize eggs and allow normal embryo development⁠. Few studies explore sperm quality using aquatic invertebrates. Parhyale hawaiensis is a marine amphipod with a circumtropical distribution and considered a model for evolution, development, and ecotoxicological studies. We aimed to develop a methodology to collect sperm cells of P. hawaiensis and evaluate their viability and DNA damage (comet assay). We directly exposed the sperm cells to different mutagenic agents to optimize/develop the protocols. Then, as a proof of concept, we exposed the males to mutagenic compounds (EMS, benzo[a]pyrene (BaP), azo and anthraquinone dyes) at non-lethal concentrations verified by the proposed viability test and analyzed their sperm cells for DNA damage (comet assay). Organisms exposed to EMS presented a clear concentration response in the DNA damage response. We also showed that BaP was able to induce a statistically significant increase in DNA damage of the sperm cells. For the two dyes, although DNA damage increased, statistically differences were not observed. We believe we successfully developed a test to detect genotoxicity of chemicals in sperm cells using an invertebrate model. The protocol for sperm cell viability needs to be further explored with different chemicals to verify its utility as a toxicity endpoint. The developed genotoxicity test has the advantages to employ organisms that are easily cultivated in reduced space, use simple laboratory resources and reduced amount of material and reagents. Positive responses with this model could be used to disclose new germ cell mutagen candidates which could be further confirmed in vertebrates' systems.

From darkness to twilight: Morphological divergence between cave and surface-subterranean ecotone Niphargus species.

Subterranean and surface habitats are in stark contrast in several environmental factors. Therefore, adaptation to the subterranean environment typically impedes the (re)colonisation of surface habitats. The genus Niphargus includes amphipod crustaceans that primarily occupy subterranean habitats. All its species show typical adaptations to the subterranean environment. However, some Niphargus species occur in surface-subterranean ecotones. To understand whether (i) habitat-based phenotypic divergence is present between the cave and the ecotone species and (ii) similar phenotypes emerge independently in each ecotone, we studied morphological divergence between four cave and four ecotone Niphargus species based on 13 functional morphological traits. To account for different selection acting on the sexes, we included both males (N = 244) and females (N = 222). Nine out of 13 traits showed habitat-divergence. Traits related to feeding and crawling were shorter, while traits related to oxygenation were larger in ecotone species. Eleven out of 13 traits were sexually dimorphic. Traits related to oxygenation and crawling were larger in females, while the trait related to swimming was larger in males. We found that the extent of sexual dimorphism differs between the habitats in eight traits related to sensing, feeding, oxygenation and crawling. Additionally, we found that in certain traits related to sensing and oxygenation, habitat-related differences are only present in one sex, but not the other. We conclude that the detected differences between the cave and the ecotone species indicate divergent evolution, where similarities among the different species within habitat type indicate convergent evolution. The high degree of sexual dimorphism paired with differences in sexual dimorphism between the habitats in certain traits suggest that sexual and fecundity selections have comparable effects to environmental selection. Thus, studies of habitat-dependent adaptations investigating one sex only, or not considering sexual dimorphism, can lead to erroneous conclusions.

The mitochondrial genome of Bottapotamon fukienense (Brachiura: Potamidae) is fragmented into two chromosomes.

BACKGROUND: China is the hotspot of global freshwater crab diversity, but their wild populations are facing severe pressures associated with anthropogenic factors, necessitating the need to map their taxonomic and genetic diversity and design conservation policies. RESULTS: Herein, we sequenced the mitochondrial genome of a Chinese freshwater crab species Bottapotamon fukienense, and found that it is fragmented into two chromosomes. We confirmed that fragmentation was not limited to a single specimen or population. Chromosome 1 comprised 15,111 base pairs (bp) and there were 26 genes and one pseudogene (pseudo-nad1) encoded on it. Chromosome 2 comprised 8,173 bp and there were 12 genes and two pseudogenes (pseudo-trnL2 and pseudo-rrnL) encoded on it. Combined, they comprise the largest mitogenome (23,284 bp) among the Potamidae. Bottapotamon was the only genus in the Potamidae dataset exhibiting rearrangements of protein-coding genes. Bottapotamon fukienense exhibited average rates of sequence evolution in the dataset and did not differ in selection pressures from the remaining Potamidae. CONCLUSIONS: This is the first experimentally confirmed fragmentation of a mitogenome in crustaceans. While the mitogenome of B. fukienense exhibited multiple signs of elevated mitogenomic architecture evolution rates, including the exceptionally large size, duplicated genes, pseudogenisation, rearrangements of protein-coding genes, and fragmentation, there is no evidence that this is matched by elevated sequence evolutionary rates or changes in selection pressures.

Cadmium exposure elicited dynamic RNA m6A modification and epi-transcriptomic regulation in the Pacific whiteleg shrimp Litopenaeus vannamei.

N6-methyladenosine (m6A) methylation is the most prevalent post-transcriptional RNA modification in eukaryotic organisms, but its roles in the regulation of physiological resistance of marine crustaceans to heavy metal pollutants are poorly understood. In this study, the transcriptome-wide m6A RNA methylation profiles and dynamic m6A changes induced by acute Cd2+ exposure in the the pacific whiteleg shrimp Litopenaeus vannamei were comprehensively analyzed. Cd2+ toxicity caused a significant reduction in global RNA m6A methylation level, with major m6A regulators including the m6A methyltransferase METTL3 and the m6A binding protein YTHDF2 showing declined expression. Totally, 11,467 m6A methylation peaks from 6415 genes and 17,291 peaks within 7855 genes were identified from the Cd2+ exposure group and the control group, respectively. These m6A peaks were predominantly enriched in the 3' untranslated region (UTR) and around the start codon region of the transcripts. 7132 differentially expressed genes (DEGs) and 7382 differentially m6A-methylated genes (DMGs) were identified. 3186 genes showed significant changes in both gene expression and m6A methylation levels upon cadmium exposure, and they were related to a variety of biological processes and gene pathways. Notably, an array of genes associated with antioxidation homeostasis, transmembrane transporter activity and intracellular detoxification processes were significantly enriched, demonstrating that m6A modification may mediate the physiological responses of shrimp to cadmium toxicity via regulating ROS balance, Cd2+ transport and toxicity mitigation. The study would contribute to a deeper understanding of the evolutionary and functional significance of m6A methylation to the physiological resilience of decapod crustaceans to heavy metal toxicants.

Reconstruction of Eriocheir sinensis Protein-Protein Interaction Network Based on DGO-SVM Method.

Eriocheir sinensis is an economically important aquatic animal. Its regulatory mechanisms underlying many biological processes are still vague due to the lack of systematic analysis tools. The protein-protein interaction network (PIN) is an important tool for the systematic analysis of regulatory mechanisms. In this work, a novel machine learning method, DGO-SVM, was applied to predict the protein-protein interaction (PPI) in E. sinensis, and its PIN was reconstructed. With the domain, biological process, molecular functions and subcellular locations of proteins as the features, DGO-SVM showed excellent performance in Bombyx mori, humans and five aquatic crustaceans, with 92-96% accuracy. With DGO-SVM, the PIN of E. sinensis was reconstructed, containing 14,703 proteins and 7,243,597 interactions, in which 35,604 interactions were associated with 566 novel proteins mainly involved in the response to exogenous stimuli, cellular macromolecular metabolism and regulation. The DGO-SVM demonstrated that the biological process, molecular functions and subcellular locations of proteins are significant factors for the precise prediction of PPIs. We reconstructed the largest PIN for E. sinensis, which provides a systematic tool for the regulatory mechanism analysis. Furthermore, the novel-protein-related PPIs in the PIN may provide important clues for the mechanism analysis of the underlying specific physiological processes in E. sinensis.

Two faces of one coin: Beneficial and deleterious effects of reactive oxygen species during short-term acclimation to hypo-osmotic stress in a decapod crab.

Exposure to environmental changes often results in the production of reactive oxygen species (ROS), which, if uncontrolled, leads to loss of cellular homeostasis and oxidative distress. However, at physiological levels these same ROS are known to be key players in cellular signaling and the regulation of key biological activities (oxidative eustress). While ROS are known to mediate salinity tolerance in plants, little is known for the animal kingdom. In this study, we use the Mediterranean crab Carcinus aestuarii, highly tolerant to salinity changes in its environment, as a model to test the healthy or pathological role of ROS due to exposure to diluted seawater (dSW). Crabs were injected either with an antioxidant [N-acetylcysteine (NAC), 150 mg·kg-1] or phosphate buffered saline (PBS). One hour after the first injection, animals were either maintained in seawater (SW) or transferred to dSW and injections were carried out at 12-h intervals. After ≈48 h of salinity change, all animals were sacrificed and gills dissected for analysis. NAC injections successfully inhibited ROS formation occurring due to dSW transfer. However, this induced 55% crab mortality, as well as an inhibition of the enhanced catalase defenses and mitochondrial biogenesis that occur with decreased salinity. Crab osmoregulatory capacity under dSW condition was not affected by NAC, although it induced in anterior (non-osmoregulatory) gills a 146-fold increase in Na+/K+/2Cl- expression levels, reaching values typically observed in osmoregulatory tissues. We discuss how ROS influences the physiology of anterior and posterior gills, which have two different physiological functions and strategies during hyper-osmoregulation in dSW.

Diving into broad-scale and high-resolution population genomics to decipher drivers of structure and climatic vulnerability in a marine invertebrate.

Species with widespread distributions play a crucial role in our understanding of climate change impacts on population structure. In marine species, population structure is often governed by both high connectivity potential and selection across strong environmental gradients. Despite the complexity of factors influencing marine populations, studying species with broad distribution can provide valuable insights into the relative importance of these factors and the consequences of climate-induced alterations across environmental gradients. We used the northern shrimp Pandalus borealis and its wide latitudinal distribution to identify current drivers of population structure and predict the species' vulnerability to climate change. A total of 1514 individuals sampled across 24° latitude were genotyped at high geographic (54 stations) and genetic (14,331 SNPs) resolutions to assess genetic variation and environmental correlations. Four populations were identified in addition to finer substructure associated with local adaptation. Geographic patterns of neutral population structure reflected predominant oceanographic currents, while a significant proportion of the genetic variation was associated with gradients in salinity and temperature. Adaptive landscapes generated using climate projections suggest a larger genomic offset in the southern extent of the P. borealis range, where shrimp had the largest adaptive standing genetic variation. Our genomic results combined with recent observations point to further deterioration in southern regions and an impending vulnerable status in the regions at higher latitudes for P. borealis. They also provide rare insights into the drivers of population structure and climatic vulnerability of a widespread meroplanktonic species, which is crucial to understanding future challenges associated with invertebrates essential to ecosystem functioning.

Crustacean endocrinology: Sexual differentiation and potential application for aquaculture.

Crustaceans, which represent a significant subset of arthropods, are classified into three major classes: Ostracoda, Malacostraca, and Branchiopoda. Among them, sex manipulation in decapod species from the Malacostraca class has been extensively researched for aquaculture purposes and to study reproductive physiology and sexual plasticity. Some decapods exhibit sexual dimorphism that influences their biological and economic value. Monosex culture, in which only one sex is cultivated, increases production yields while reducing the risk of invasiveness, as genetic leakage into natural waters is less likely to occur. Differences in yield are also observed when cultivating different sexes, with all-male cultures of Macrobrachium rosenbergii being more profitable than both mixed and all-female cultures. Research on decapod sexual differentiation has led to a better understanding of sex determination and sexual differentiation processes in arthropods. Similar to most mammals and other vertebrate classes, Malacostraca crustaceans, including decapods, exhibit a cell-non-autonomous mode of sexual development. Genetic factors (e.g., sex chromosomes) and endocrine factors (e.g., insulin-like androgenic gland factor and crustacean female sex hormone) play pivotal roles in the development of sexually dimorphic traits. This review synthesizes the existing understanding of sex determination mechanisms and the role of sex hormones in decapod species. Additionally, it provides an overview of the methyl farnesoate, which has been suggested to be involved in male sex differentiation in some crab species, as well as the phenomenon of male-to-female sex reversal in host decapods caused by parasitic crustaceans.

Arginine Promoted Ovarian Development in Pacific White Shrimp Litopenaeus vannamei via the NO-sGC-cGMP and TORC1 Signaling Pathways.

This study aimed to evaluate the effects of arginine (0.5%, 1%, 1.5%, 2%, and 2.5% arginine supplementation levels were selected) on the ovarian development of Pacific white shrimp (Litopenaeus vannamei). The analyzed arginine supplementation levels in each diet were 2.90%, 3.58%, 4.08%, 4.53%, 5.04%, and 5.55%, respectively. A total of 540 shrimp (an initial weight of approximately 14 g) with good vitality were randomly distributed into six treatments, each of which had three tanks (300 L in volume filled with 200 L of water), with 30 shrimp per duplicate. Shrimp were fed three times a day (6:00 a.m., 11:00 a.m., and 6:00 p.m.). The results showed that after the 12-week raring cycle, shrimp fed with 4.08% and 4.53% Arg achieved better ovary development, which was identified by ovarian stage statistics, ovarian morphology observation, serum hormone levels (methylfarneside (MF); 5-hydroxytryptamine (5-HT); estradiol (E2); and gonadotropin-releasing hormone (GnRH)), gene expression (DNA meiotic recombinase 1 (dmc1), proliferating cell nuclear antigen (pcna), drosophila steroid hormone 1 (cyp18a), retinoid X receptor (rxra), and ecdysone receptor (ecr)). Further in-depth analysis showed that 4.08% and 4.53% Arg supplementation increased the concentration of vitellogenin in hepatopancreas and serum (p < 0.05) and upregulated the expression level of hepatopancreatic vg and vgr (p < 0.05), which promoted the synthesis of hepatopancreas exogenous vitellogenin and then transported it into the ovary through the vitellogenin receptor and further promoted ovarian maturation in L. vannamei. Meanwhile, compared with the control group, the expression level of vg in the ovary of the 4.53% Arg group was significantly upregulated (p < 0.05), which indicated endogenous vitellogenin synthesis in ovarian maturation in L. vannamei. Moreover, the expression of genes related to the mechanistic target of the rapamycin complex 1 (mTORC1) pathway and protein levels was regulated by dietary arginine supplementation levels. Arginine metabolism-related products, including nitric oxide synthase (NOS), nitric oxide (NO), and cyclic guanosine monophosphate (cGMP), were also affected. RNA interference was applied here to study the molecular regulation mechanism of arginine on ovarian development in L. vannamei. A green fluorescent protein (GFP)-derived double-stranded RNA (dsGFP) is currently commonly used as a control, while TOR-derived dsRNA (dsTOR) and NOS-derived dsRNA (dsNOS) were designed to build the TOR and NOS in vivo knockdown model. The results showed that the mTORC1 and NO-sGC-cGMP pathways were inhibited, while the vitellogenin receptor and vitellogenin gene expression levels were downregulated significantly in the hepatopancreas and ovary. Overall, dietary arginine supplementation could enhance endogenous and exogenous vitellogenin synthesis to promote ovary development in L. vannamei, and the appropriate dosages were 4.08% and 4.53%. The NO-sGC-cGMP and mTORC1 signaling pathways mediated arginine in the regulation of ovary development in L. vannamei.

Chitosan Scaffolds from Crustacean and Fungal Sources: A Comparative Study for Bone-Tissue-Engineering Applications.

Chitosan (CS), a biopolymer, holds significant potential in bone regeneration due to its biocompatibility and biodegradability attributes. While crustacean-derived CS is conventionally used in research, there is growing interest in fungal-derived CS for its equally potent properties in bone regenerative applications. Here, we investigated the physicochemical and biological characteristics of fungal (MDC) and crustacean (ADC)-derived CS scaffolds embedded with different concentrations of tricalcium phosphate minerals (TCP), i.e., 0(wt)%: ADC/MDC-1, 10(wt)%: ADC/MDC-2, 20(wt)%: ADC/MDC-3 and 30(wt)%: ADC/MDC-4. ADC-1 and MDC-1 lyophilised scaffolds lacking TCP minerals presented the highest zeta potentials of 47.3 ± 1.2 mV and 55.1 ± 1.6 mV, respectively. Scanning electron microscopy revealed prominent distinctions whereby MDC scaffolds exhibited striation-like structural microarchitecture in contrast to the porous morphology exhibited by ADC scaffold types. With regard to the 4-week scaffold mass reductions, MDC-1, MDC-2, MDC-3, and MDC-4 indicated declines of 55.98 ± 4.2%, 40.16 ± 3.6%, 27.05 ± 4.7%, and 19.16 ± 5.3%, respectively. Conversely, ADC-1, ADC-2, ADC-3, and ADC-4 presented mass reductions of 35.78 ± 5.1%, 25.19 ± 4.2%, 20.23 ± 6.3%, and 13.68 ± 5.4%, respectively. The biological performance of the scaffolds was assessed through in vitro bone marrow mesenchymal stromal cell (BMMSCs) attachment via indirect and direct cytotoxicity studies, where all scaffold types presented no cytotoxic behaviours. MDC scaffolds indicated results comparable to ADC, where both CS types exhibited similar physiochemical properties. Our data suggest that MDC scaffolds could be a potent alternative to ADC-derived scaffolds for bone regeneration applications, particularly for 10(wt)% TCP concentrations.

Microplastic extraction from digestive tracts of large decapods.

The reliable quantification of microplastic contamination in chitinous organisms requires validated methods to remove interfering complex organic and inorganic material. This study trialled KOH, H2O2 and HNO3 digestion methods on the digestive tracts of two large decapods (Panulirus cygnus and Portunus armatus) to validate a protocol that facilitates reliable microplastic extraction. KOH digestion provided the best recovery (>95 %) of all polymers (e.g. polyamide, polyethylene, polyethylene terephthalate, polypropylene, polystyrene and polyvinyl chloride), with the lowest impact to their physical morphology and chemical spectra. While HNO3, and HNO3 + H2O2 treatments were more effective at digesting chitin, they destroyed polyamide, and altered several other polymers. High digestion efficiency did not result in high matrix clarification or high microplastic recovery for large decapods. This study emphasises the importance of validating species-specific microplastic extraction methods, whilst proposing additional post-digestion protocols, such as density separation, for complex samples, that can be applied in future research investigating plastic contamination in large decapods.

An i-type lysozyme from a crustacean, Pacifastacus leniusculus, functions as a clot-destabilising enzyme.

Lysozymes are hydrolytic enzymes, and they are ubiquitous among all living organisms. They are mostly associated with antibacterial properties through their muramidase activity, while other properties such as iso-peptidase activity are also common. Invertebrate-type (i-type) lysozymes include the enzyme Destabilase, which is present in the salivary secretions of the medicinal leach Hirundo medicinalis. Destabilase has the ability to hydrolyse the ε-(γ-glutamyl)-lysine iso-peptide bonds formed by transglutaminase in fibrin of vertebrate blood, thereby destabilising blood clots. We have identified an i-type lysozyme from the hemocytes of the freshwater crayfish Pacifastacus leniusculus, which was found to be upregulated at the protein level in response to an injection of the ß-1,3-glucan laminarin. Based on its sequence we predicted that this lysozyme would lack muramidase activity, and therefore we decided to determine its putative immune function. The P. leniusculus i-type lysozyme (Pl-ilys), is a protein with 159 amino acid residues, including a 29 residue signal peptide, with a predicted molecular weight of 16 kDa and a predicted pI of 5.6. It is expressed primarily in the hemocytes and to a lesser extent in the hematopoietic tissue. A recombinant mature Pl-ilys using an E. coli expression system was produced, and we could ascertain that this enzyme was deficient of muramidase activity. Moreover, no iso-peptidase activity could be detected against the substrate l-γ-glutamine-p-nitroanilide. Analysis of the conserved domains in Pl-ilys showed a putative destabilase domain, and thus we tested the clot dissolving activity of this enzyme. We could show that the purified P. leniusculus clotting protein which had been coagulated and clotted with transglutaminase was dissolved by the addition of Pl-ilys. Taken together our results indicate that Pl-ilys has a clot dissolving or destabilising activity in crustacean blood.

Anatomical and molecular insights into the antennal gland of the giant freshwater prawn Macrobrachium rosenbergii.

In this study, the complex organization of the AnG in the giant freshwater prawn Macrobrachium rosenbergii was revealed using various techniques, including conventional histology, histochemistry, scanning electron microscopy, and X-ray tomography. The results showed the diversity of cells in the AnG and the detailed organization of the labyrinth's tubule into four radiated areas from the central to peripheral zones. The study also demonstrated the expression of some vertebrate kidney-associated homolog genes, aquaporin (AQP), solute carrier family 22 (SLC-22), nephrin, and uromodulin, in the AnG by qPCR. The result of in situ hybridization further showed the localization of SLC-22 and AQP transcript in the bladder and labyrinth's epithelium, specifically in regions 2, 3, and 4. Additionally, the study revealed neuropeptide expressions in the AnG by qPCR and in situ hybridization, i.e., crustacean hyperglycemic hormone (CHH) and molt inhibiting hormone (MIH), implying that the AnG may have a role in hormone production. Moreover, male and female prawns exhibited different levels of AQP, SLC-22, nephrin, and CHH expressions during the premolt and intermolt stages, suggesting a crucial role relevant to the molting stages. In conclusion, this study clarified the complex structure of the AnG in M. rosenbergii and demonstrated for the first time the expression of vertebrate kidney-associated genes and the possible endocrine role of the AnG. Further investigation is needed to clarify the role of these genes, particularly during ecdysis. The implications of these findings could significantly advance our understanding of the AnG in decapod crustaceans.

NinaB and BCO Collaboratively Participate in the ß-Carotene Catabolism in Crustaceans: A Case Study on Chinese Mitten Crab Eriocheir sinensis.

Carotenoid cleavage oxygenases can cleave carotenoids into a range of biologically important products. Carotenoid isomerooxygenase (NinaB) and ß, ß-carotene 15, 15'-monooxygenase (BCO1) are two important oxygenases. In order to understand the roles that both oxygenases exert in crustaceans, we first investigated NinaB-like (EsNinaBl) and BCO1-like (EsBCO1l) within the genome of Chinese mitten crab (Eriocheir sinensis). Their functions were then deciphered through an analysis of their expression patterns, an in vitro ß-carotene degradation assay, and RNA interference. The results showed that both EsNinaBl and EsBCO1l contain an RPE65 domain and exhibit high levels of expression in the hepatopancreas. During the molting stage, EsNinaBl exhibited significant upregulation in stage C, whereas EsBCO1l showed significantly higher expression levels at stage AB. Moreover, dietary supplementation with ß-carotene resulted in a notable increase in the expression of EsNinaBl and EsBCO1l in the hepatopancreas. Further functional assays showed that the EsNinaBl expressed in E. coli underwent significant changes in its color, from orange to light; in addition, its ß-carotene cleavage was higher than that of EsBCO1l. After the knockdown of EsNinaBl or EsBCO1l in juvenile E. sinensis, the expression levels of both genes were significantly decreased in the hepatopancreas, accompanied by a notable increase in the redness (a*) values. Furthermore, a significant increase in the ß-carotene content was observed in the hepatopancreas when EsNinaBl-mRNA was suppressed, which suggests that EsNinaBl plays an important role in carotenoid cleavage, specifically ß-carotene. In conclusion, our findings suggest that EsNinaBl and EsBCO1l may exhibit functional co-expression and play a crucial role in carotenoid cleavage in crabs.

Relationship between crustacean consumption and serum perfluoroalkyl substances (PFAS): the Korean National Environmental Health Survey (KoNEHS) cycle 4.

Background: Perfluoroalkyl substances (PFASs) are non-aromatic organic compounds, whose hydrogen atoms in the carbon chain substituted by fluorine atoms. PFASs exhibit developmental toxicity, carcinogenicity, hepatotoxicity, reproductive toxicity, immunotoxicity, and hormone toxicity. PFASs are used in the production of disposable food packages, aircraft and automobile devices, cooking utensils, outdoor gear, furniture and carpets, aqueous film forming foam (AFFF), cables and wires, electronics, and semiconductors. This study aimed to determine the association between crustacean consumption and serum PFASs. Methods: Adult participants (2,993) aged ≥ 19 years were extracted from the 4th cycle data of the Korean National Environmental Health Survey (KoNEHS). Based on the 50th percentile concentrations of serum PFASs, participants were divided into the low-concentration group (LC) and the high-concentration group (HC). General characteristics, dietary factors, coated product usage, and personal care product usage, an independent t-test and χ2 test were analyzed. The odds ratio (OR) of serum PFAS concentration against crustacean consumption was estimated via logistic regression analysis adjusting for general characteristics, dietary factors, coated product usage, and personal care product usage. Results: The OR for the HC of serum PFASs was higher in individuals with ≥once a week crustacean consumption than in those with < once a week crustacean consumption. Estimated ORs were perfluorohexanesulfonic acid 2.15 (95% confidence interval [CI]: 1.53-3.02), perfluorononanoic acid (PFNA) 1.23 (95% CI: 1.07-1.41), and perfluorodecanoic acid (PFDeA) 1.42 (95% CI: 1.17-1.74) in males, and perfluorooctanoic acid 1.48 (95% CI: 1.19-1.84), perfluorooctanesulfonic acid 1.39 (95% CI: 1.27-1.52), PFNA 1.70 (95% CI: 1.29-2.26) and PFDeA 1.43 (95% CI: 1.32-1.54) in females. Conclusions: This study revealed the association between the crustacean consumption and concentrations of serum PFASs in general Korean population.

Influence of environmental patterns on the population structure and secondary production of the fiddler crab Uca maracoani (Latreille) in the Amazon mangroves.

Uca maracoani is a fiddler crab found in estuaries along the western Atlantic coast, with a notable preference for euhaline environments. This study aimed to analyze the population structure and dynamics of this species in an estuary on the North Coast of Brazil, specifically in an area of the upper estuary where seasonal rainfall fluctuations result in significant changes in salinity. Monthly crab samples were taken from December 2013 to November 2015, together with measurements of environmental variables, such as water and climate parameters. The population maintains a balanced sex ratio; however, males are generally larger, with lower mortality rates and longer lifespans than females. Reproduction is continuous but mainly takes place in the dry season when salinity levels are higher (above 12‰). Higher crab densities have been observed during the rainy season when, despite lower salinity levels (below 10‰), the conditions for survival (food availability and milder climate) seem to be more favorable. The estimated average annual biomass and production for the population were 2.62 g AFDM m-2 and 5.43 g AFDM m-2 year-1, respectively, characterized by a high turnover rate (P/B = 2.10 year-1). Our results suggest that U. maracoani has thriving populations in the Amazon coast's mangroves, benefiting from the vast muddy intertidal zone and the high organic content delivered by the estuaries.

Temporal distribution of microplastics and other anthropogenic particles in four marine species from the Atlantic coast (France).

The characterization of microplastic (MP) contamination in marine species is increasing as concerns about environmental and food safety are more and more discussed. Here, we reported a quantitative and qualitative assessment of the contamination by anthropogenic particles (from visual sorting; AP) and MP (plastic-made) in the whole soft body or digestive tract of marine species. Four commercial species were studied, namely the Pacific oyster (Magallana gigas), the spiny spider crab (Maja sp.), the common sole (Solea solea) and seabass (Dicentrarchus labrax or punctatus). AP and MP uptake were studied over three to four seasons depending on the species. After tissues digestion, particles were extracted under a stereomicroscope and morphometric characteristics were reported. Then, polymers were identified by ATR-FTIR spectroscopy. Seasonal variations were mainly described in the Pacific oyster as AP uptake was lower in autumn and MP uptake was higher in spring. These variations may be linked to the reproduction and growth cycles of this species. Moreover, seabass ingestion was lower in autumn compared to winter. Contamination in spider crabs and soles showed either weak or no seasonal trends, both quantitatively and qualitatively. Overall, AP contamination in all studied species ranged from 1.17 ± 1.89 AP.ind-1 (in sole) to 4.07 ± 6.69 AP.ind-1 (in seabass) while MP contamination ranged from 0.10 ± 0.37 MP.ind-1 (in sole) to 1.09 ± 3.06 MP.ind-1 (in spider crab). Fibers were mostly reported in all species (at least 77.7%), along with cellulosic polymers (at least 43.7%). AP and MP uptake were detected in all species and at almost all seasons, with the only exception of the common sole during autumn. Therefore, this study emphasizes the ubiquity of AP and MP contamination in marine species and provides new knowledges about seasonal uptake by commercial species.

A brief and updated introduction to the neuroendocrine system of crustaceans.

The neuroendocrine system of crustaceans is complex and regulates many processes, such as development, growth, reproduction, osmoregulation, behavior, and metabolism. Once stimulated, crustaceans' neuroendocrine tissues modulate the release of monoamines, ecdysteroids, and neuropeptides that can act as hormones or neurotransmitters. Over a few decades, research has unraveled some mechanisms governing these processes, substantially contributing to understanding crustacean physiology. More aspects of crustacean neuroendocrinology are being comprehended with molecular biology, transcriptome, and genomics analyses. Hence, these studies will also significantly enhance the ability to cultivate decapods, such as crabs and shrimps, used as human food sources. In this review, current knowledge on crustacean endocrinology is updated with new findings about crustacean hormones, focusing mainly on the main neuroendocrine organs and their hormones and the effects of these molecules regulating metabolism, growth, reproduction, and color adaptation. New evidence about vertebrate-type hormones found in crustaceans is included and discussed. Finally, this review may assist in understanding how the emerging chemicals of environmental concern can potentially impair and disrupt crustacean's endocrine functions and their physiology.

Considerations for cultivated crustacean meat: potential cell sources, potential differentiation and immortalization strategies, and lessons from crustacean and other animal models.

Cultivated crustacean meat (CCM) is a means to create highly valued shrimp, lobster, and crab products directly from stem cells, thus removing the need to farm or fish live animals. Conventional crustacean enterprises face increasing pressures in managing overfishing, pollution, and the warming climate, so CCM may provide a way to ensure sufficient supply as global demand for these products grows. To support the development of CCM, this review briefly details crustacean cell culture work to date, before addressing what is presently known about crustacean muscle development, particularly the molecular mechanisms involved, and how this might relate to recent work on cultivated meat production in vertebrate species. Recognizing the current lack of cell lines available to establish CCM cultures, we also consider primary stem cell sources that can be obtained non-lethally including tissues from limbs which are readily released and regrown, and putative stem cells in circulating hemolymph. Molecular approaches to inducing myogenic differentiation and immortalization of putative stem cells are also reviewed. Finally, we assess the current status of tools available to CCM researchers, particularly antibodies, and propose avenues to address existing shortfalls in order to see the field progress.

The language of light: a review of bioluminescence in deep-sea decapod shrimps.

In the dark, expansive habitat of the deep sea, the production of light through bioluminescence is commonly used among a wide range of taxa. In decapod crustaceans, bioluminescence is only known in shrimps (Dendrobranchiata and Caridea) and may occur in different modes, including luminous secretions that are used to deter predators and/or from specialised light organs called photophores that function by providing camouflage against downwelling light. Photophores exhibit an extensive amount of morphological variation across decapod families: they may be internal (of hepatic origin) or embedded in surface tissues (dermal), and may possess an external lens, suggesting independent origins and multiple functions. Within Dendrobranchiata, we report bioluminescence in Sergestidae, Aristeidae, and Solenoceridae, and speculate that it may also be found in Acetidae, Luciferidae, Sicyonellidae, Benthesicymidae, and Penaeidae. Within Caridea, we report bioluminescence in Acanthephyridae, Oplophoridae, Pandalidae, and new observations for Pasiphaeidae. This comprehensive review includes historic taxonomic literature and recent studies investigating bioluminescence in all midwater and deep benthic shrimp families. Overall, we report known or suspected bioluminescence in 157 species across 12 families of decapod shrimps, increasing previous records of bioluminescent species by 65%. Mounting evidence from personal observations and the literature allow us to speculate the presence of light organs in several families thought to lack bioluminescence, making this phenomenon much more common than previously reported. We provide a detailed discussion of light organ morphology and function within each group and indicate future directions that will contribute to a better understanding of how deep-sea decapods use the language of light.