Metabolic changes in antennal glands of Caribbean spiny lobsters Panulirus argus infected by Panulirus argus virus 1 (PaV1).

Panulirus argus virus 1 (PaV1) (Family Mininucleoviridae) causes chronic and systemic infection in wild juvenile spiny lobsters Panulirus argus (Latreille, 1804), ending in death by starvation and metabolic wasting. In marine decapods, the antennal gland is involved in osmoregulation and excretion. In this compact organ, fluid is filtered from the hemolymph, and ions are reabsorbed to produce a hypotonic urine. Although PaV1 is released with the urine in infected individuals, little is known regarding the metabolic effect of PaV1 in the antennal gland. The objective of this study was to perform a comparative evaluation of the metabolic profile of the antennal gland of clinically PaV1-infected lobsters versus those with no clinical signs of infection, using proton nuclear magnetic resonance analysis. Overall, 48 compounds were identified, and the most represented metabolites were those involved in carbohydrate, amino acid, energy, and nucleotide metabolism. Most of the metabolites that were down-regulated in the infected group were essential and non-essential amino acids. Some metabolites involved in the urea cycle and carbohydrate metabolism were also altered. This study represents a first approach to the metabolic evaluation of the antennal gland. We broadly discuss alterations in the content of several proteinogenic and non-proteinogenic amino acids and other key metabolites involved in energetic and nucleotide metabolism.

A first glimpse into the transcriptomic changes induced by the PaV1 infection in the gut of Caribbean spiny lobsters, Panulirus argus (Latreille, 1804) (Decapoda: Achelata: Palinuridae).

The Caribbean spiny lobster, Panulirus argus (Latreille, 1804) supports important fisheries in the Caribbean region. This species is affected by a deadly virus, Panulirus argus Virus 1 (PaV1), the only known pathogenic virus for this species. As infection progresses, the effects of PaV1 on its host become systemic, with far reaching impacts on the host's physiology, including structural injuries to its gastrointestinal organs, such as the hepatopancreas and the gut. This last one becomes highly compromised in the last stages of infection. Since the gut is a key organ for the physiological stability of lobsters, we compared the transcriptomic changes in the gut of juvenile individuals of Panulirus argus naturally infected with PaV1. In the RNA-Seq analysis, we obtained a total of 485 × 106 raw reads. After cleaning, reads were de novo assembled into 68,842 transcripts and 50,257 unigenes. The length of unigenes ranged from 201 bp to 28,717 bp, with a N50 length of 2079, and a GC content of 40.61%. In the differential gene expression analysis, we identified a total of 3405 non redundant differential transcripts, of which 1920 were up-regulated and 1485 were down-regulated. We found alterations in transcripts encoding for proteins involved in transcriptional regulation, splicing, postraductional regulation, protein signaling, transmembrane transport, cytoskeletal regulation, and proteolysis, among others. This is the first insight into the transcriptomic regulation of PaV1-P. argus interaction. The information generated can help to unravel the molecular mechanisms that may intervene in the gut during PaV1 infection.

Gill and liver transcriptomic responses of Achirus lineatus (Neopterygii: Achiridae) exposed to water-accommodated fraction (WAF) of light crude oil reveal an onset of hypoxia-like condition.

Crude oil is one of the most widespread pollutants released into the marine environment, and native species have provided useful information about the effect of crude oil pollution in marine ecosystems. We consider that the lined sole Achirus lineatus can be a useful monitor of the effect of crude oil in the Gulf of Mexico (GoM) because this flounder species has a wide distribution along the GoM, and its response to oil components is relevant. The objective of this study was to compare the transcriptomic changes in liver and gill of adults lined sole fish (Achirus lineatus) exposed to a sublethal acute concentration of water-accommodated fraction (WAF) of light crude oil for 48 h. RNA-Seq was performed to assess the transcriptional changes in both organs. A total of 1073 differentially expressed genes (DEGs) were detected in gills; 662 (61.69%) were upregulated, and 411 (38.30%) were downregulated whereas in liver, 515 DEGs; 306 (59.42%) were upregulated, and 209 (40.58%) were downregulated. Xenobiotic metabolism and redox metabolism, along with DNA repair mechanisms, were activated. The induction of hypoxia-regulated genes and the generalized regulation of multiple signaling pathways support the hypothesis that WAF exposition causes a hypoxia-like condition.

Alterations in the gut-associated microbiota of juvenile Caribbean spiny lobsters Panulirus argus (Latreille, 1804) infected with PaV1.

The spiny lobster Panulirus argus (Latreille, 1804) is currently affected by an unenveloped, icosahedral, DNA virus termed Panulirus argus virus 1 (PaV1), a virulent and pathogenic virus that produces a long-lasting infection that alters the physiology and behaviour of heavily infected lobsters. Gut-associated microbiota is crucial for lobster homeostasis and well-being, but pathogens could change microbiota composition affecting its function. In PaV1 infection, the changes of gut-associated microbiota are yet to be elucidated. In the present study, we used high-throughput 16S rRNA sequencing technology to compare the bacterial microbiota in intestines of healthy and heavily PaV1-infected male and female juveniles of spiny lobsters P. argus captured in Puerto Morelos Reef lagoon, Quintana Roo, Mexico. We found that basal gut-associated microbiota composition showed a sex-dependent bias, with females being enriched in amplicon sequence variants (ASVs) assigned to Sphingomonas, while males were enriched in the genus Candidatus Hepatoplasma and Aliiroseovarius genera. Moreover, the alpha diversity of microbiota decreased in PaV1-infected lobsters. A significant increase of the genus Candidatus Bacilloplasma was observed in infected lobsters, as well as a significant decrease in Nesterenkonia, Caldalkalibacillus, Pseudomonas, Cetobacterium and Phyllobacterium. We also observed an alteration in the abundances of Vibrio species. Results from this study suggest that PaV1 infection impacts intestinal microbiota composition in Panulirus argus in a sex-dependent manner.

iTRAQ-Based Proteomic Profile Analysis of the Hepatopancreas of Caribbean Spiny Lobsters Infected With Panulirus argus Virus 1: Metabolic and Physiological Implications.

The Caribbean spiny lobster Panulirus argus (Latreille, 1084) sustains economically valuable fisheries throughout the wider Caribbean region. This species is currently affected by the pathogenic virus Panulirus argus Virus 1 (PaV1) that causes a systemic and chronic-degenerative infection in juvenile spiny lobsters P. argus. To date, there is no available information regarding the host alterations induced by this pathogen at the molecular level. In the present study, comparative proteomic analyses of the changes in the hepatopancreas between infected and non-infected juvenile lobsters were analyzed by isobaric tags for relative and absolute quantitation (iTRAQ) coupled to synchronous precursor selection (SPS)-based MS3. We identified a total of 636 proteins, being 68 down-regulated and 71 up-regulated proteins. Among the down-regulated proteins, we identified several enzymes involved in the metabolism of hormones and lipids, digestive proteases and glycosidases, while proteins associated with the histone core, protein synthesis, immune response and RNA regulation were up-regulated. Several misregulated enzymes involved in the regulation of neuromodulators were also identified. RT-qPCR assays were used to validate the expression of transcripts encoding for selected differential proteins that were in concordance to proteomic data, as well as the tendency observed in the enzymatic activities of trypsin, chymotrypsin, and glycosidase. In a similar way, we observed glycogen reduction in muscle, and an increase in plasma acylglycerides and glucose, which may be explained by proteomic data. This study provides the first insight into the molecular changes in the hepatopancreas of Caribbean spiny lobsters associated to PaV1 infection. Data provided herein would help to clarify the origin of the molecular misregulations observed at macroscopic level in this host-pathogen interaction.