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1.
PLoS One ; 19(6): e0302433, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38865356

RESUMO

The timing of American horseshoe crab (Limulus polyphemus) spawning behavior along the coast of Florida (United States) is generally associated with the highest tides during the spring and fall lunar cycles. All Florida estuaries support horseshoe crab populations, but tidal characteristics vary markedly among locations, which may influence the timing of horseshoe crab spawning behavior. The Indian River Lagoon is a large microtidal estuary on Florida's east coast. Given the microtidal nature of the lagoon, it is unclear which environmental factors affect horseshoe spawning. In 2019, volunteers of Florida Horseshoe Crab Watch conducted daily surveys at two sites in the northern Indian River Lagoon during peak spawning months (February-April). During each survey, volunteers counted all spawning horseshoe crabs and recorded environmental variables, including water temperature, air temperature, wind speed, wind direction, salinity, and tide height. We developed a suite of negative-binomial regression models to quantify relationships between the number of spawning horseshoe crabs and environmental factors. Modeling results indicated a positive relationship between onshore wind speed and number of spawning horseshoe crabs. Our study suggests that in the absence of tidal cues, onshore wind speed may be an important driver of horseshoe crab spawning activity in microtidal estuarine systems.


Assuntos
Caranguejos Ferradura , Animais , Florida , Caranguejos Ferradura/fisiologia , Temperatura , Estações do Ano , Estuários , Reprodução/fisiologia , Vento , Ondas de Maré , Salinidade , Rios
2.
Nat Commun ; 15(1): 3808, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38714651

RESUMO

Euchelicerata is a clade of arthropods comprising horseshoe crabs, scorpions, spiders, mites and ticks, as well as the extinct eurypterids (sea scorpions) and chasmataspidids. The understanding of the ground plans and relationships between these crown-group euchelicerates has benefited from the discovery of numerous fossils. However, little is known regarding the origin and early evolution of the euchelicerate body plan because the relationships between their Cambrian sister taxa and synziphosurines, a group of Silurian to Carboniferous stem euchelicerates with chelicerae and an unfused opisthosoma, remain poorly understood owing to the scarce fossil record of appendages. Here we describe a synziphosurine from the Lower Ordovician (ca. 478 Ma) Fezouata Shale of Morocco. This species possesses five biramous appendages with stenopodous exopods bearing setae in the prosoma and a fully expressed first tergite in the opisthosoma illuminating the ancestral anatomy of the group. Phylogenetic analyses recover this fossil as a member of the stem euchelicerate family Offacolidae, which is characterized by biramous prosomal appendages. Moreover, it also shares anatomical features with the Cambrian euarthropod Habelia optata, filling the anatomical gap between euchelicerates and Cambrian stem taxa, while also contributing to our understanding of the evolution of euchelicerate uniramous prosomal appendages and tagmosis.


Assuntos
Artrópodes , Evolução Biológica , Fósseis , Filogenia , Animais , Artrópodes/anatomia & histologia , Artrópodes/classificação , Artrópodes/genética , Marrocos , Caranguejos Ferradura/anatomia & histologia , Caranguejos Ferradura/genética , Caranguejos Ferradura/classificação , Biodiversidade
3.
Mar Biotechnol (NY) ; 26(3): 575-587, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38676851

RESUMO

The vitellogenin present in the bloodstream undergoes internalization into developing oocytes through the vitellogenin receptor (VgR), a process mediated by receptor-mediated endocytosis. VgR plays a crucial role in facilitating the accumulation of vitellogenin and the maturation of oocytes. In this study, we characterized a Tachypleus tridentatus vitellogenin receptor (TtVgR) gene from the tri-spine horseshoe crab, revealing a length of 1956 bp and encoding 652 amino acid residues with 12 exons. TtVgR has a molecular weight of 64.26 kDa and an isoelectric point of 5.95. Predictions indicate 85 phosphorylation sites and 7 glycosylation sites within TtVgR. Transcriptional analysis demonstrated specific expression of TtVgR in the ovary and yellow connective tissue. TtVgR was identified and distributed in the plasma membrane of oocytes. The siRNA-mediated TtVgR knockdown significantly reduced the transcriptional activity of TtVgR. This depletion induced excessive ROS production, resulting in DNA damage in ovarian primary cells. TUNEL and flow cytometry analyses confirmed ovarian cell apoptosis following TtVgR knockdown, indicating DNA damage in ovarian primary cells. These findings underscore the importance of TtVgR in ovarian cell development, suggesting its potential involvement in vitellogenesis and oocyte maturation. This knowledge may inform innovative breeding strategies and contribute to the sustainable management and conservation of the tri-spine horseshoe crab.


Assuntos
Técnicas de Silenciamento de Genes , Caranguejos Ferradura , Ovário , RNA Interferente Pequeno , Receptores de Superfície Celular , Animais , Feminino , Ovário/metabolismo , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/genética , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Caranguejos Ferradura/genética , Caranguejos Ferradura/metabolismo , Apoptose/genética , Oócitos/metabolismo , Sequência de Aminoácidos , Espécies Reativas de Oxigênio/metabolismo , Filogenia , Proteínas do Ovo
4.
Methods Mol Biol ; 2789: 87-99, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38506994

RESUMO

Monitoring endotoxin contamination in drugs and medical devices is required to avoid pyrogenic responses and septic shock in patients receiving these products. Endotoxin contamination of engineered nanomaterials and nanotechnology-based medical products represents a significant translational hurdle. Nanoparticles often interfere with an in vitro limulus amebocyte lysate (LAL) assay commonly used in the pharmaceutical industry for the detection and quantification of endotoxin. Such interference challenges the preclinical development of nanotechnology-formulated drugs and medical devices containing engineered nanomaterials. Protocols for the analysis of nanoparticles using LAL assays have been reported before. Here, we discuss considerations for selecting an LAL format and describe a few experimental approaches for overcoming nanoparticle interference with the LAL assays to obtain more accurate estimations of endotoxin contamination in nanotechnology-based products. The discussed approaches do not solve all types of nanoparticle interference with the LAL assays but could be used as a starting point to address the problem. This chapter also describes approaches to prevent endotoxin contamination in nanotechnology-formulated products.


Assuntos
Endotoxinas , Nanopartículas , Animais , Humanos , Endotoxinas/análise , Bioensaio/métodos , Caranguejos Ferradura , Nanotecnologia
5.
Mar Environ Res ; 197: 106467, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38520956

RESUMO

Marine hypoxia poses a significant challenge in the contemporary marine environment. The horseshoe crab, an ancient benthic marine organism, is confronted with the potential threat of species extinction due to hypoxia, making it an ideal candidate for studying hypoxia tolerance mechanisms. In this experiment, juvenile Tachypleus tridentatus were subjected to a 21-day trial at DO:2 mg/L (hypoxia) and DO:6 mg/L conditions. The experimental timeline included a 14-day exposure phase followed by a 7-day recovery period. Sampling occurred on days 0, 7, 14, and 21, where the period from day 14 to day 21 corresponds to seven days of recuperation. Several enzymatic activities of important proteins throughout this investigation were evaluated, such as succinate dehydrogenase (SDH), phosphofructokinase (PFK), hexokinase (HK), lactate dehydrogenase (LDH), and pyruvate kinase (PK). Concurrently, the relative expression of hexokinase-1 (HK), hypoxia-inducible factor 1-alpha inhibitor (FIH), and hypoxia-inducible factor 1-alpha (HIF-1α), pyruvate dehydrogenase phosphatase (PDH), succinate dehydrogenase assembly factor 4 (SDH), and Glucose-6-phosphatase (G6Pase) were also investigated. These analyses aimed to elucidate alterations in the hypoxia signaling pathway and respiratory energy metabolism. It is revealed that juvenile T. tridentatus initiated the HIF pathway under hypoxic conditions, resulting in an upregulation of HIF-1α and FIH-1 gene expression, which in turn, influenced a shift in metabolic patterns. Particularly, the activity of glycolysis-related enzymes was promoted significantly, including PK, HK, PKF, LDH, and the related HK gene. In contrast, enzymes linked to aerobic respiration, PDH, and SDH, as well as the related PDH and SDH genes, displayed down-regulation, signifying a transition from aerobic to anaerobic metabolism. Additionally, the activity of gluconeogenesis-related enzymes such as PK and G6Pase gene expression were significantly elevated, indicating the activation of gluconeogenesis and glycogenolysis pathways. Consequently, juvenile T. tridentatus demonstrated an adaptive response to hypoxic conditions, marked by changes in respiratory energy metabolism modes and the activation of hypoxia signaling pathways.


Assuntos
Caranguejos Ferradura , Succinato Desidrogenase , Animais , Caranguejos Ferradura/genética , Caranguejos Ferradura/metabolismo , Succinato Desidrogenase/metabolismo , Hexoquinase/metabolismo , Hipóxia/metabolismo , Transdução de Sinais , Glucose/metabolismo , Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo
6.
J Hazard Mater ; 468: 133801, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38377908

RESUMO

Pollution with anthropogenic contaminants including antibiotics and nanoplastics leads to gradual deterioration of the marine environment, which threatens endangered species such as the horseshoe crab Tachypleus tridentatus. We assessed the potential toxic mechanisms of an antibiotic (norfloxacin, 0, 0.5, 5 µg/L) and polystyrene nanoparticles (104 particles/L) in T. tridentatus using biomarkers of tissue redox status, molting, and gut microbiota. Exposure to single and combined pollutants led to disturbance of redox balance during short-term (7 days) exposure indicated by elevated level of a lipid peroxidation product, malondialdehyde (MDA). After prolonged (14-21 days) exposure, compensatory upregulation of antioxidants (catalase and glutathione but not superoxide dismutase) was observed, and MDA levels returned to the baseline in most experimental exposures. Transcript levels of molting-related genes (ecdysone receptor, retinoic acid X alpha receptor and calmodulin A) and a molecular chaperone (cognate heat shock protein 70) showed weak evidence of response to polystyrene nanoparticles and norfloxacin. The gut microbiota T. tridentatus was altered by exposures to norfloxacin and polystyrene nanoparticles shown by elevated relative abundance of Bacteroidetes. At the functional level, evidence of suppression by norfloxacin and polystyrene nanoparticles was found in multiple intestinal microbiome pathways related to the genetic information processing, metabolism, organismal systems, and environmental information processing. Future studies are needed to assess the physiological and health consequences of microbiome dysbiosis caused by norfloxacin and polystyrene nanoparticles and assist the environmental risk assessment of these pollutants in the wild populations of the horseshoe crabs.


Assuntos
Poluentes Ambientais , Caranguejos Ferradura , Animais , Caranguejos Ferradura/genética , Norfloxacino/toxicidade , Poliestirenos/toxicidade , Estresse Oxidativo
7.
Sci Rep ; 14(1): 3968, 2024 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-38368470

RESUMO

Horseshoe crabs are among the most studied invertebrates due to their unique, innate immune system and biological processes. The metabolomics study was conducted on lipopolysaccharide (LPS)-stimulated and non-stimulated hemocytes isolated from the Malaysian Tachypleus gigas and Carcinoscorpius rotundicauda. LC-TOF-MS, multivariate analyses, principal component analysis (PCA), and partial least squares-discriminant analysis (PLS-DA) were included in this study to profile the metabolites. A total of 37 metabolites were identified to be differentially abundant and were selected based on VIP > 1. However, of the 37 putative metabolites, only 23 were found to be significant with ANOVA at p < 0.05. The metabolites were identified using several databases, and the literature review of the metabolites was reported in the manuscript. Thus, this study has provided further insights into the putative metabolites' presence in the hemocytes of horseshoe crabs that are stimulated and non-stimulated with LPS and their abundance in each species. Several putative metabolites showed they have medicinal values from previous studies.


Assuntos
Caranguejos Ferradura , Lipopolissacarídeos , Animais , Hemócitos , Caranguejos Ferradura/imunologia , Caranguejos Ferradura/metabolismo , Lipopolissacarídeos/farmacologia
8.
Front Cell Infect Microbiol ; 14: 1322264, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38328671

RESUMO

With advances in medicine, increasing medical interventions have increased the risk of invasive fungal disease development. (1-3)-ß-D glucan (BDG) is a common fungal biomarker in serological tests. However, the scarcity of Limulus resources for BDG detection poses a challenge. This study addresses the need for an alternative to Limulus amebocyte lysate by using BDG mutant antibody for chemiluminescence detection. The wild-type BDG antibody was obtained by immunizing rabbits. An optimal V52HI/N34L Y mutant antibody, which has increased 3.7-fold of the testing efficiency compared to the wild-type antibody, was first achieved by mutating "hot-spot" residues that contribute to strong non-covalent bonds, as determined by alanine scanning and molecular dynamics simulation. The mutant was then applied to develop the magnetic particle chemiluminescence method. 574 clinical samples were tested using the developed method, with a cutoff value of 95 pg/mL set by Limulus amebocyte lysate. The receiver operating characteristic curve demonstrated an area under the curve of 0.905 (95% CI: 0.880-0.929). Chemiluminescence detected an antigen concentration of 89.98 pg/mL, exhibiting a sensitivity of 83.33% and specificity of 89.76%. In conclusion, the results showed a good agreement with Limulus amebocyte lysate and demonstrated the feasibility of using BDG mutant antibodies for invasive fungal disease diagnosis. The new method based on chemiluminescence for detecting BDG could shorten the sample-to-result time to approximately 30 min, rescue Limulus from being endangered and is resource efficient in terms of equipment and the non-use of a skilled technician.


Assuntos
Infecções Fúngicas Invasivas , beta-Glucanas , Animais , Coelhos , Caranguejos Ferradura , Curva ROC , Sequência de Bases , Sensibilidade e Especificidade
9.
Zoo Biol ; 43(2): 205-209, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38223996

RESUMO

Atlantic horseshoe crabs (Limulus polyphemus) are prevalent in public aquarium touch pools. Despite their popularity, the literature concerning medical management under managed care is sparse. Noninfectious conditions include trauma to the exoskeleton and compound eyes; however, injury to the soft tissue connecting the telson and opisthosoma has not been previously reported. This report describes telson avulsion in three Atlantic horseshoe crabs at a public aquarium and attempted external stabilization with a vascular silicone tie in two of three affected animals. The horseshoe crab that received no veterinary intervention suffered a complete telson amputation 1 month after the initial injury. Although the two other horseshoe crabs did well postoperatively, and external stabilization prevented further avulsion or amputation, they still could not right themselves if flipped into dorsal recumbency. All three horseshoe crabs were ultimately euthanized due to animal welfare concerns. To avoid potentially serious telson ligament injury, horseshoe crabs should never be picked up by the telson. The authors recommend that telson ligament injuries be addressed promptly, any inciting cause be mitigated, and external stabilization be considered earlier.


Assuntos
Animais de Zoológico , Caranguejos Ferradura , Animais , Tato
10.
Sci Rep ; 14(1): 2410, 2024 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-38287051

RESUMO

The determination of lipopolysaccharide (endotoxin) in serum or plasma samples using Limulus amebocyte lysate (LAL)-based assays is currently not sufficiently reliable in clinical diagnostics due to numerous interfering factors that strongly reduce the recovery of LPS in clinical samples. The specific plasma components responsible for the endotoxin neutralizing capacity of human blood remain to be identified. There are indications that certain endotoxin-neutralizing proteins or peptides, which are part of the host defense peptides/proteins of the innate immune system may be responsible for this effect. Based on our finding that several antimicrobial peptides can be neutralized by the polyanion heparin, we developed a heparin-containing diluent for serum and plasma samples, which enables reliable quantification of LPS measurement in clinical samples using the LAL assay. In a preclinical study involving 40 donors, this improved protocol yielded an over eightfold increase in LPS recovery in serum samples, as compared to the standard protocol. This modified protocol of sample pretreatment could make LPS measurement a valuable tool in medical diagnostics.


Assuntos
Endotoxinas , Caranguejos Ferradura , Animais , Humanos , Lipopolissacarídeos , Teste do Limulus/métodos , Heparina
11.
Mar Environ Res ; 193: 106282, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38042633

RESUMO

Despite being widely distributed in Asia, Carcinoscorpius rotundicauda is often overlooked and, its population status remains unclear. Moreover, it is threatened by illegal harvesting and degradation of mangrove ecosystems. Protecting its habitat is essential for population and biodiversity conservation, as mangroves provide nursery grounds and food supply for C. rotundicauda. This review discusses the biological characteristics of C. rotundicauda, including ecology, nutrition, life history, toxicology, and immunology. It also presents information about its distribution and population status. The review emphasizes the challenges faced by C. rotundicauda and proposes a conservation framework that involves the participation of local residents to facilitate conservation efforts. Collaboration between local residents and communities is proposed to protect and monitor the mangrove ecosystem. Additionally, this framework can support field research, protect C. rotundicauda juveniles and other species, and ensure the livelihood of local residents through participation in carbon trading markets and eco-industries such as eco-farming and eco-tourism.


Assuntos
Ecossistema , Caranguejos Ferradura , Animais , Biodiversidade , Ecologia
12.
Environ Toxicol Pharmacol ; 105: 104345, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38103811

RESUMO

Mercury (Hg) pollution is threatening the health of endangered Tachypleus tridentatus whereas the toxic mechanism is still unclear. This study combined transcriptomic and metabolomics technology to reveal the toxic mechanisms of mercury (Hg 2+, 0.025 mg/L) exposing to T. tridentatus larvae for 15 days. Mercury induced cellular toxicity and cardiovascular dysfunction by dysregulating the genes related to endocrine system, such as polyubiquitin-A, cathepsin B, atrial natriuretic peptide, etc. Mercury induced lipid metabolic disorder with the abnormal increase of lysoPC, leukotriene D4, and prostaglandin E2. Cytochrome P450 pathway was activated to produce anti-inflammatory substances to reconstruct the homeostasis. Mercury also inhibited arginine generation, which may affect the development of T. tridentatus by disrupting the crucial signaling pathway. The mercury methylation caused enhancement of S-adenosylmethionine to meet the need of methyl donor. The mechanisms described in present study provide new insight into the risk assessment of mercury exposure to T. tridentatus.


Assuntos
Caranguejos Ferradura , Mercúrio , Animais , Caranguejos Ferradura/química , Caranguejos Ferradura/genética , Espécies em Perigo de Extinção , Perfilação da Expressão Gênica , Transcriptoma
13.
Proc Biol Sci ; 290(2013): 20232212, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38113938

RESUMO

The ability to enrol for protection is an effective defensive strategy that has convergently evolved multiple times in disparate animal groups ranging from euarthropods to mammals. Enrolment is a staple habit of trilobites, and their biomineralized dorsal exoskeleton offered a versatile substrate for the evolution of interlocking devices. However, it is unknown whether trilobites also featured ventral adaptations for enrolment. Here, we report ventral exoskeletal adaptations that facilitate enrolment in exceptionally preserved trilobites from the Middle Ordovician Walcott-Rust Quarry in New York State, USA. Walcott-Rust trilobites reveal the intricate three-dimensional organization of the non-biomineralized ventral anatomy preserved as calcite casts, including the spatial relationship between the articulated sternites (i.e. ventral exoskeletal plates) and the wedge-shaped protopodites. Enrolment in trilobites is achieved by ventrally dipping the anterior margin of the sternites during trunk flexure, facilitated by the presence of flexible membranes, and with the close coupling of the wedge-shaped protopodites. Comparisons with the ventral morphology of extant glomerid millipedes and terrestrial isopods reveal similar mechanisms used for enrolment. The wedge-shaped protopodites of trilobites closely resemble the gnathobasic coxa/protopodite of extant horseshoe crabs. We propose that the trilobites' wedge-shaped protopodite simultaneously facilitated tight enrolment and gnathobasic feeding with the trunk appendages.


Assuntos
Artrópodes , Evolução Biológica , Animais , Fósseis , Artrópodes/anatomia & histologia , Caranguejos Ferradura , New York , Mamíferos
14.
Appl Microbiol Biotechnol ; 107(24): 7463-7473, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37882851

RESUMO

Horseshoe crab Factor G is a heterodimeric serine protease zymogen that is activated by (1→3)-ß-D-glucans (BDG) from fungal cell walls. This reaction is used in diagnostic agents for deep-seated mycosis. At present, functional analysis using Factor G from Tachypleus tridentatus has been performed, and genetic information has been published, but reconstitution using recombinant proteins has not yet been achieved. In this study, we cloned the genes for Factor G α and ß from Limulus polyphemus; two gene sequences were obtained for Factor G α and seven for ß. The obtained L. polyphemus Factor G α was used to specifically remove BDG from the culture medium for eliminating the activator BDG. The optimal combination for each sequence was examined with BDG removal medium, and a combination was found that featured BDG-dependent activity. These results indicate that a BDG assay system using recombinant Factor G is feasible in reconstitution. This research will support future reagent development that does not require natural horseshoe crab resources. KEY POINTS: • Cloned novel Factor G α subunit and ß subunit genes from L. polyphemus • Proposed a method of removing BDG without reducing culture medium performance • Identified combination of recombinant α and ß subunits for BDG-dependent activation.


Assuntos
Caranguejos Ferradura , beta-Glucanas , Animais , Caranguejos Ferradura/genética , Caranguejos Ferradura/metabolismo , Serina Endopeptidases/metabolismo
15.
Altern Lab Anim ; 51(6): 401-410, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37855095

RESUMO

The Bacterial Endotoxins Test (BET) is a critical safety test that is used to detect bacterial endotoxins, which are the major contributor to fever-inducing contamination risks known as pyrogens. All parenteral therapies, including every lot of injected drugs, vaccines, medical devices, must be tested for pyrogens to ensure patient safety. Bacterial endotoxins test methods were developed as a highly sensitive detection method for bacterial endotoxins, after the discovery of a clotting cascade in horseshoe crab blood. However, horseshoe crab species are limited to some inshore coastal habitats along the Atlantic coast of the USA and others throughout Asia. Fully functional horseshoe crab clotting factors can be manufactured via recombinant protein production, and several BET methods featuring recombinant horseshoe crab proteins have now been developed for commercial use. Recombinant Bacterial Endotoxins Test (rBET) methods based on the use of recombinant Factor C (rFC) were established in the European Pharmacopoeia - however, these methods have not yet been granted compendial status in the United States Pharmacopoeia (USP). In order to facilitate dialogue between stakeholders, the Physicians Committee for Responsible Medicine hosted two virtual roundtable discussions on the perceived barriers to the use of rBET methods for US FDA requirements. Stakeholders agreed that multiple rFC-based methods have been demonstrated to have suitable analytical performance, as described in ICH Q2 on the Validation of Analytical Procedures and USP <1225> on the Validation of Compendial Procedures. United States Pharmacopoeia compendial inclusion of the rFC-based and other rBET methods was favoured, in order to reduce the additional burdens created by a lack of global harmonisation on BET testing requirements.


Assuntos
Pirogênios , Vacinas , Animais , Humanos , Segurança de Equipamentos , Endotoxinas/metabolismo , Caranguejos Ferradura/metabolismo , Vacinas/metabolismo , Teste do Limulus/métodos
16.
Science ; 381(6661): 932-933, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37651522

RESUMO

Proposal could allow synthetic proteins to replace harvested enzyme in drug testing.


Assuntos
Fatores de Coagulação Sanguínea , Conservação dos Recursos Naturais , Caranguejos Ferradura , Teste do Limulus , Animais , Sangue
17.
Mar Environ Res ; 191: 106128, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37587001

RESUMO

Nanoplastics (NPs) and heavy metals are typical marine pollutants, affecting the gut microbiota composition and molting rate of marine organisms. Currently, there is a lack of research on the toxicological effects of combined exposure to horseshoe crabs. In this study, we investigated the effects of NPs and copper on the expression of molt-related genes and gut microbiome in juvenile tri-spine horseshoe crabs Tachypleus tridentatus by exposing them to NPs (100 nm, 104 particles L-1) and/or Cu2+ (10 µgL-1) in seawater for 21 days. Compared with the control group, the relative mRNA expression of ecdysone receptor (EcR), retinoid x receptor (RXR), calmodulin-A-like isoform X1 (CaM X1), and heat shock 70 kDa protein (Hsp70) were significantly increased under the combined stress of NPs and Cu2+. There were no significant differences in the diversity and abundance indices of the gut microbial population of horseshoe crabs between the NPs and/or Cu2+ groups and the control group. According to linear discriminant analysis, Oleobacillus was the most abundant microorganism in the NPs and Cu2+ stress groups. These results indicate that exposure to either NPs stress alone or combined NPs and Cu2+ stress can promote the expression levels of juvenile molting genes. NPs exposure has a greater impact on the gut microbial community structure of juvenile horseshoe crabs compared to Cu2+ exposure. This study is helpful for predicting the growth and development of horseshoe crabs under complex environmental pollution.


Assuntos
Microbioma Gastrointestinal , Caranguejos Ferradura , Animais , Caranguejos Ferradura/química , Caranguejos Ferradura/genética , Cobre/toxicidade , Microplásticos , Muda
18.
Int J Mol Sci ; 24(15)2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37569474

RESUMO

The development of sensitive methods for the detection of endotoxin molecules, such as lipopolysaccharides (LPS), is essential for food safety and health control. Conventional analytical methods used for LPS detection are based on the pyrogen test, plating and culture-based methods, and the limulus amoebocyte lysate method (LAL). Alternatively, the development of reliable biosensors for LPS detection would be highly desirable to solve some critical issues, such as high cost and a long turnaround time. In this work, we present a label-free Surface-Enhanced Raman Spectroscopy (SERS)-based method for LPS detection in its free form. The proposed method combines the benefits of plasmonic enhancement with the selectivity provided by a specific anti-lipid A antibody (Ab). A high-enhancing nanostructured silver substrate was coated with Ab. The presence of LPS was quantitatively monitored by analyzing the changes in the Ab spectra obtained in the absence and presence of LPS. A limit of detection (LOD) and quantification (LOQ) of 12 ng/mL and 41 ng/mL were estimated, respectively. Importantly, the proposed technology could be easily expanded for the determination of other biological macromolecules.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Animais , Endotoxinas , Lipopolissacarídeos , Análise Espectral Raman , Caranguejos Ferradura , Nanopartículas Metálicas/química
19.
Int J Biol Macromol ; 246: 125563, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37364812

RESUMO

Recently, chitin biopolymer has received much attention as a wide variety of biomedical application for this and its derivatives have been reported, in fact, the study of non-conventional species as alternative sources of them compounds has taken particular interest. Here, we present a comparative physicochemical survey of the two tagmata in the exoskeleton of the horseshoe crab Limulus polyphemus: the prosoma and the opisthosoma, collected in Yucatán, Mexico. The characterization included CHNSO analysis, FTIR, TGA, DSC, XRD, and SEM. The CHNSO analysis revealed that C is present in the highest proportion (∼45 %) and that chemical composition did not show significant differences (P < 0.05) between the two tagmata. FTIR spectra of two tagmata presented a wide characteristic band of the chitin between 3600 and 3000 cm-1, confirming the presence of this biopolymer in the exoskeleton studied. TGA and DTGA profiles resulted very similar for both tagmata being the residual mass at 650 °C of around 30 % for both samples; these values were associated to the presence of minerals. SEM micrographs showed a porous matrix with infinite large number of irregularly shaped particles. Results show that both tagmata are made up of chitin, and they seem to have a high mineral content.


Assuntos
Exoesqueleto , Quitina , Caranguejos Ferradura , Caranguejos Ferradura/química , Animais , Exoesqueleto/química , Exoesqueleto/ultraestrutura , Microscopia Eletrônica de Varredura , Quitina/química
20.
Mar Pollut Bull ; 188: 114726, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36860019

RESUMO

The booming coastal zone economy poses increasing anthropogenic threats to marine life and habitats. Using the endangered living fossil horseshoe crab (HSC) as an example, we quantified the intensity of various anthropogenic pressures along the coast of Hainan Island, China, and for the first time assessed their impact on the distribution of juvenile HSCs through a field survey, remote sensing, spatial geographic modeling, and machine learning methods. The results indicate that the Danzhou Bay needs to be protected as a priority based on species and anthropogenic pressure information. Aquaculture and port activities dramatically impact the density of HSCs and therefore be managed priority. Finally, a threshold effect between total, coastal residential, and beach pressure and the density of juvenile HSCs were detected, which indicates the need for a balance between development and conservation as well as the designation of suitable sites for the construction of marine protected areas.


Assuntos
Caranguejos Ferradura , Atividades Humanas , Humanos , Animais , China , Efeitos Antropogênicos , Aquicultura
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