Predatory bacteria in the haemolymph of the cultured spiny lobster Panulirus ornatus.
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ABSTRACT:
SUBMITTER: Ooi MC
PROVIDER: S-EPMC8743626 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Lobsters have an open circulatory system with haemolymph that contains microorganisms even in the healthy individuals. Understanding the role of these microorganisms becomes increasingly important particularly for the diagnosis of disease as the closed life-cycle aquaculture of the spiny lobster Panulirus ornatus nears commercial reality. This study aimed to characterise haemolymph responses of healthy cultured P. ornatus juveniles at control (28?°C) and elevated (34?°C) temperatures. This was assessed by measuring immune parameters (total granulocyte counts, total haemocyte counts, clotting times), and culture-independent (pyrosequencing of haemolymph DNA) and culture-dependent (isolation using nonselective growth medium) techniques to analyse bacterial communities from lobster haemolymph sampled on days 0, 4 and 6 post-exposure to the temperature regimes. Elevated temperature (34?°C) affected lobster survival, total granulocyte counts, and diversity, load and functional potential of the haemolymph bacterial community. Pyrosequencing analyses showed that the core haemolymph microbiome consisted of phyla Proteobacteria and Bacteriodetes. Overall, culture-independent methods captured a higher bacterial diversity and load when compared to culture-dependent methods, however members of the Rhodobacteraceae were strongly represented in both analyses. This is the first comprehensive study providing comparisons of haemolymph bacterial communities from healthy and thermally stressed cultured juvenile P. ornatus and has the potential to be used in health monitoring programs.
| S-EPMC6368590 | biostudies-literature
Project description:The type strain of Vibrio owensii (DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus). V. owensii DY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease epizootics. Vectored challenge via the aquaculture live feed organism Artemia (brine shrimp) caused consistent cumulative mortality rates of 84 to 89% after 72 h, in contrast to variable mortality rates seen after immersion challenge. Histopathological examination of vector-challenged phyllosomas revealed bacterial proliferation in the midgut gland (hepatopancreas) concomitant with epithelial cell necrosis. A fluorescent-protein-labeled V. owensii DY05 transconjugant showed dispersal of single cells in the foregut and hepatopancreas 6 h postexposure, leading to colonization of the entire hepatopancreas within 18 h and eventually systemic infection. V. owensii DY05 is a marine enteropathogen highly virulent to P. ornatus phyllosoma that uses vector-mediated transmission and release from host association to a planktonic existence to perpetuate transfer. This understanding of the infection process will improve targeted biocontrol strategies and enhance the prospects of commercially viable larviculture for this valuable spiny lobster species.
| S-EPMC3318833 | biostudies-literature
Project description:Vibrio owensii DY05 is a serious pathogen causing epizootics in the larviculture of ornate spiny lobster Panulirus ornatus. In the present study a multi-tiered probiotic screening strategy was used to identify a probiotic combination capable of protecting P. ornatus larvae (phyllosomas) from experimental V. owensii DY05 infection. From a pool of more than 500 marine bacterial isolates, 91 showed definitive in vitro antagonistic activity towards the pathogen. Antagonistic candidates were shortlisted based on phylogeny, strength of antagonistic activity, and isolate origin. Miniaturized assays used a green fluorescent protein labelled transconjugant of V. owensii DY05 to assess pathogen growth and biofilm formation in the presence of shortlisted candidates. This approach enabled rapid processing and selection of candidates to be tested in a phyllosoma infection model. When used in combination, strains Vibrio sp. PP05 and Pseudoalteromonas sp. PP107 significantly and reproducibly protected P. ornatus phyllosomas during vectored challenge with V. owensii DY05, with survival not differing significantly from unchallenged controls. The present study has shown the value of multispecies probiotic treatment and demonstrated that natural microbial communities associated with wild phyllosomas and zooplankton prey support antagonistic bacteria capable of in vivo suppression of a pathogen causing epizootics in phyllosoma culture systems.
| S-EPMC3390342 | biostudies-literature
Project description:Sexual development involves the successive and overlapping processes of sex determination, sexual differentiation, and ultimately sexual maturation, enabling animals to reproduce. This provides a mechanism for enriched genetic variation which enables populations to withstand ever-changing environments, selecting for adapted individuals and driving speciation. The molecular mechanisms of sexual development display a bewildering diversity, even in closely related taxa. Many sex determination mechanisms across animals include the key family of "doublesex- and male abnormal3-related transcription factors" (Dmrts). In a few exceptional species, a single Dmrt residing on a sex chromosome acts as the master sex regulator. In this study, we provide compelling evidence for this model of sex determination in the ornate spiny lobster Panulius ornatus, concurrent with recent reports in the eastern spiny lobster Sagmariasus verreauxi. Using a multi-tissue transcriptomic database established for P. ornatus, we screened for the key factors associated with sexual development (by homology search and using previous knowledge of these factors from related species), providing an in-depth understanding of sexual development in decapods. Further research has the potential to close significant gaps in our understanding of reproductive development in this ecologically and commercially significant order.
| S-EPMC7600227 | biostudies-literature
Project description:A thorough understanding of the microorganisms and pathogens associated with the larval stage of the tropical ornate rock lobster, Panulirus ornatus, is required to overcome disease outbreaks that currently block aquaculture attempts. This study used microscopy in addition to culture and molecularly based microbiological techniques to characterize the bacterial community associated with cultured, developmental stage PI to PII P. ornatus phyllosomas. Scanning electron microscopy demonstrated colonization of phyllosomas by filamentous, rod-shaped, and coccus-shaped bacteria. A clone library constructed from dead phyllosomas sampled from the larval rearing tank on day 10 was dominated by Thiothrix-affiliated sequences (56% of clones). A comparable library from live phyllosomas also contained Thiothrix-affiliated sequences, though these only represented 19% of clones within the library. Fluorescent in situ hybridization (FISH) confirmed identification of the filamentous bacteria as Thiothrix sp., being present on dead phyllosomas. FISH also identified Leucothrix sp. and Vibrio sp., as well as a range of other rod- and coccus-shaped bacteria, colonizing both live and dead phyllosomas. The development of the microbial community associated with phyllosomas was monitored through a standard larval rearing run using denaturing gradient gel electrophoresis (DGGE). Vibrio sp.-affiliated bands dominated the profiles of live animals through the rearing period and dead phyllosomas sampled on selected days. The population of Vibrio sp. associated with phyllosomas was monitored with culture-based analysis on selective media and demonstrated to increase significantly on day 7, coinciding with the beginning of the larval molt. An isolated Vibrio harveyi strain demonstrated an identical 16S rRNA sequence with retrieved DGGE and clone library sequences. Colonization of phyllosomas with filamentous bacterial species potentially hinders the ability of the animals to molt and, combined with the added stress of the molt process, likely results in reduced immune function, allowing opportunistic pathogenic Vibrio sp. to cause larval mortalities.
| S-EPMC1828824 | biostudies-literature
Project description:Panulirus argus is a keystone species and target of the most lucrative fishery in the Caribbean region. This study reports, for the first time, the complete mitochondrial genome of Panulirus argus (average coverage depth nucleotide-1 = 70×) assembled from short Illumina 150 bp PE reads. The AT-rich mitochondrial genome of Panulirus argus was 15 739 bp in length and comprised 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 22 transfer RNA genes. A single 801 bp long intergenic space was assumed to be the D-loop. Most of the PCGs were encoded on the H-strand. The gene order observed in the mitochondrial genome of Panulirus argus corresponds to the presumed Pancrustacean ground pattern. KA/KS ratios calculated for all mitochondrial PCGs showed values < 1, indicating that all these PCGs are evolving under purifying selection. A maximum likelihood phylogenetic analysis (concatenated PCGs [n = 13], 154 arthropods) supported the monophyly of the Achelata and other infraorders within the Decapoda. Mitochondrial PCGs have enough phylogenetic informativeness to explore high-level genealogical relationships in the Pancrustacea. The complete mitochondrial genome of the Caribbean spiny lobster Panulirus argus will contribute to the better understanding of meta-population connectivity in this keystone overexploited species.
| S-EPMC6283867 | biostudies-literature
Project description:The ornate spiny rock lobster, Panulirus ornatus, is an attractive candidate for aquaculture. The larval stages of spiny lobsters, known as phyllosoma, are complex with many developmental stages. Very little is known about the inorganic element composition of phyllosoma. In this study, a novel method using synchrotron X-ray fluorescence microscopy (XFM) was applied to investigate the distributions of metals potassium (K), calcium (Ca), copper (Cu), zinc (Zn), the metalloid arsenic (As), and nonmetal bromine (Br) within individual phyllosoma at stages 3, 4, and 8 of their development. For the first time, 1 µm resolution synchrotron XFM images of whole phyllosoma as well as closer examinations of their eyes, mouths, setae, and tails were obtained. Elements accumulated in certain locations within phyllosoma, providing insight into their likely biological role for these organisms. This information may be useful for the application of dietary supplementation in the future to closed larval cycle lobster aquaculture operations.
| S-EPMC10311473 | biostudies-literature
Project description:The tropical rock lobster, Panulirus ornatus, is a commercially important aquaculture species exhibiting complex social interactions in laboratory culture, including cannibalism of moulting conspecifics. Cannibalism of soft-shelled post-moult stage individuals is a major limitation during the juvenile stage of culture. Not limited to P. ornatus, cannibalism is widespread across farmed decapods, limiting stocking densities in crab, freshwater crayfish, and prawn species. To understand the mechanisms driving this behaviour and reduce its prevalence, we have investigated the role of chemoreception via the aesthetasc-bearing region of the lateral antennular flagellum, in the recognition of conspecific moulting cues. Differential expression analysis of several tissues in P. ornatus shows an upregulation of 70 ionotropic receptor isoforms, including co-receptors (IR25a and IR93a) and divergent receptors (IR4, IR7, and IR21a) in the aesthetasc-bearing region of the antennules. Deafferentation of the aesthetascs via deionised water exposure prevents juveniles from responding to conspecific moulting cues in a two-current choice flume, suggesting chemoreception, possibly olfaction, plays a role in identifying moulting juveniles. This is the first step in understanding the mechanisms via which cannibalism is triggered in juvenile P. ornatus culture. Further work in this area will help discover means to limit cannibalism in laboratory and commercial culture.
| S-EPMC10390513 | biostudies-literature
Project description:Partial mtDNA cytochrome oxidase subunit I (COI) fragments and near entire stretch of 12S rDNA (12S) and control region (Dloop) of the Japanese spiny lobster (Panulirus japonicus) (n = 3) were amplified by PCR and used for direct nucleotide sequencing and for clone library-based nucleotide sequence analysis. Nucleotide sequences of a total of 75 clones in COI, 77 in 12S and 92 in Dloop were determined. Haplotypes of the clones matched with those obtained by direct sequencing were determined to be genuine mtDNA sequence of the individual. Phylogenetic analysis revealed several distinct groups of haplotypes in all three regions. Genuine mtDNA sequences were observed to form a group with their closely related variables, and most of these variables may be due to amplification error but a few to be heteroplasmy. Haplotypes determined as nuclear mitochondrial pseudogenes (NUMTs) formed distinct groups. Nucleotide sequence divergence (K2P distance) between genuine haplotypes and NUMTs were substantial (7.169–23.880% for COI, 1.336–23.434% for 12S, and 7.897–71.862% for Dloop). These values were comparable to or smaller than those between species of the genus Panulirus, indicating that integration of mtDNA into the nuclear genome is a continuous and dynamic process throughout pre- and post-speciation events. Double peaks in electropherograms obtained by direct nucleotide sequencing were attributed to common nucleotides shared by multiple NUMTs. Information on the heteroplasmy and NUMTs would be very important for addressing their impact on direct nucleotide sequencing and for quality control of nucleotide sequences obtained.
| S-EPMC8571370 | biostudies-literature
Project description:We have previously reported on calcium transport mechanisms in American lobster, Homarus americanus, using (45)Ca(2+) coupled with vesicle preparations of hepatopancreatic endoplasmic reticulum. The active transport of calcium across membranes bordering calcium-sequestering stores such as sarcoplasmic or endoplasmic reticulum is catalyzed by membrane-spanning proteins, the sarco-endoplasmic Ca(2+)-ATPases (SERCAs). In the study described here we used advanced bioinformatics and molecular techniques to clone SERCA from the economically important Caribbean spiny lobster, Panulirus argus. We report the complete cloning of a full-length SERCA from P. argus antenna cDNA (GenBank accession number AY702617). This cDNA has a 1020-amino acid residue open reading frame which is 90% identical to published sequences of other crustacean SERCA proteins. Our data support the hypothesis that one crustacean and three vertebrate genes controlling calcium transport were derived from a common ancestral gene.
| S-EPMC3397473 | biostudies-literature