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Scientific Reports May 2024Biofloc (BF) stands out as a promising system for sustainable shrimp farming. Optimizing various culture conditions, such as stocking density, carbohydrate source, and...
Influence of stocking density on the growth, immune and physiological responses, and cultivation environment of white-leg shrimp (Litopenaeus vannamei) in biofloc systems.
Biofloc (BF) stands out as a promising system for sustainable shrimp farming. Optimizing various culture conditions, such as stocking density, carbohydrate source, and feeding management, is crucial for the widespread adoption of the BF system. This study compares the growth performance of white-leg shrimp (Litopenaeus vannamei) in culture ponds at low density (LD) with 50 organisms/m and high density (HD) with 200 organisms/m. Post-larvae of white-leg shrimp were stocked for 16 weeks in both LD and HD groups. The LD group exhibited a superior survival rate, growth rate, and feed consumption compared to the HD group. The BF from the LD system recorded a significantly higher protein content (16.63 ± 0.21%) than the HD group (15.21 ± 0.34%). Heterotrophic bacterial counts in water did not significantly differ with stocking density. However, Vibrio count in water samples was higher in the HD group (3.59 ± 0.35 log CFU/mL) compared to the LD group (2.45 ± 0.43 log CFU/mL). The whole shrimp body analysis revealed significantly higher protein and lipid content in the LD group. In contrast, the total aerobic bacterial count in shrimp from the HD group was high, with the identification of Salmonella enterica ssp. arizonae. Additionally, Vibrio counts in shrimp samples were significantly higher in the HD group (4.63 ± 0.32 log CFU/g) compared to the LD group (3.57 ± 0.22 log CFU/g). The expression levels of immune-associated genes, including prophenoloxidase, transglutaminase, penaiedin 3, superoxide dismutase, lysozyme, serine proteinase, and the growth-related gene ras-related protein (rap-2a), were significantly enhanced in the LD group. Conversely, stress-related gene expression increased significantly in the HD group. Hepatopancreases amylase, lipase, and protease were higher in the LD group, while trypsin activity did not differ significantly. Antioxidant enzyme activity (catalase, glutathione, glutathione peroxidase, and superoxide dismutase) significantly increased in the LD group. The histological structure of hepatopancreas, musculature, and female gonads remained similar in both densities. However, negative effects were observed in the gills' histology of the HD group. These results suggest that increasing stocking density is associated with significantly negative biological, microbial, and physiological effects on white-leg shrimp under the BF system.
Topics: Animals; Penaeidae; Aquaculture; Vibrio; White
PubMed: 38750082
DOI: 10.1038/s41598-024-61328-4 -
Current Biology : CB Jun 2024The bacterial type VI secretion system (T6SS) is a widespread, kin-discriminatory weapon capable of shaping microbial communities. Due to the system's dependency on...
The bacterial type VI secretion system (T6SS) is a widespread, kin-discriminatory weapon capable of shaping microbial communities. Due to the system's dependency on contact, cellular interactions can lead to either competition or kin protection. Cell-to-cell contact is often accomplished via surface-exposed type IV pili (T4Ps). In Vibrio cholerae, these T4Ps facilitate specific interactions when the bacteria colonize natural chitinous surfaces. However, it has remained unclear whether and, if so, how these interactions affect the bacterium's T6SS-mediated killing. In this study, we demonstrate that pilus-mediated interactions can be harnessed by T6SS-equipped V. cholerae to kill non-kin cells under liquid growth conditions. We also show that the naturally occurring diversity of pili determines the likelihood of cell-to-cell contact and, consequently, the extent of T6SS-mediated competition. To determine the factors that enable or hinder the T6SS's targeted reduction of competitors carrying pili, we developed a physics-grounded computational model for autoaggregation. Collectively, our research demonstrates that T4Ps involved in cell-to-cell contact can impose a selective burden when V. cholerae encounters non-kin cells that possess an active T6SS. Additionally, our study underscores the significance of T4P diversity in protecting closely related individuals from T6SS attacks through autoaggregation and spatial segregation.
Topics: Vibrio cholerae; Type VI Secretion Systems; Fimbriae, Bacterial; Microbial Interactions
PubMed: 38749426
DOI: 10.1016/j.cub.2024.04.041 -
Frontiers in Immunology 2024The California purple sea urchin, , relies solely on an innate immune system to combat the many pathogens in the marine environment. One aspect of their molecular...
INTRODUCTION
The California purple sea urchin, , relies solely on an innate immune system to combat the many pathogens in the marine environment. One aspect of their molecular defenses is the () gene family that is upregulated in response to immune challenge. The gene sequences are highly variable both within and among animals and likely encode thousands of SpTrf isoforms within the sea urchin population. The native SpTrf proteins bind foreign targets and augment phagocytosis of a marine . A recombinant (r)SpTrf-E1-Ec protein produced by also binds but does not augment phagocytosis.
METHODS
To address the question of whether other rSpTrf isoforms function as opsonins and augment phagocytosis, six rSpTrf proteins were expressed in insect cells.
RESULTS
The rSpTrf proteins are larger than expected, are glycosylated, and one dimerized irreversibly. Each rSpTrf protein cross-linked to inert magnetic beads (rSpTrf::beads) results in different levels of surface binding and phagocytosis by phagocytes. Initial analysis shows that significantly more rSpTrf::beads associate with cells compared to control BSA::beads. Binding specificity was verified by pre-incubating the rSpTrf::beads with antibodies, which reduces the association with phagocytes. The different rSpTrf::beads show significant differences for cell surface binding and phagocytosis by phagocytes. Furthermore, there are differences among the three distinct types of phagocytes that show specific vs. constitutive binding and phagocytosis.
CONCLUSION
These findings illustrate the complexity and effectiveness of the sea urchin innate immune system driven by the natSpTrf proteins and the phagocyte cell populations that act to neutralize a wide range of foreign pathogens.
Topics: Animals; Phagocytosis; Phagocytes; Recombinant Proteins; Protein Binding; Strongylocentrotus purpuratus; Immunity, Innate; Protein Isoforms; Sea Urchins; Vibrio; Opsonin Proteins
PubMed: 38742116
DOI: 10.3389/fimmu.2024.1372904 -
The Journal of Medical Investigation :... 2024Vibrio vulnificus (V. vulnificus) is a halophilic gram-negative bacterium that inhabits coastal warm water and induce severe diseases such as primary septicemia. To...
Vibrio vulnificus (V. vulnificus) is a halophilic gram-negative bacterium that inhabits coastal warm water and induce severe diseases such as primary septicemia. To investigate the mechanisms of rapid bacterial translocation on intestinal infection, we focused on outer membrane vesicles (OMVs), which are extracellular vesicles produced by Gram-negative bacteria and deliver virulence factors. However, there are very few studies on the pathogenicity or contents of V. vulnificus OMVs (Vv-OMVs). In this study, we investigated the effects of Vv-OMVs on host cells. Epithelial cells INT407 were stimulated with purified OMVs and morphological alterations and levels of lactate dehydrogenase (LDH) release were observed. In cells treated with OMVs, cell detachment without LDH release was observed, which exhibited different characteristics from cytotoxic cell detachment observed in V. vulnificus infection. Interestingly, OMVs from a Vibrio Vulnificus Hemolysin (VVH) and Multifunctional-autoprocessing repeats-in -toxin (MARTX) double-deletion mutant strain also caused cell detachment without LDH release. Our results suggested that the proteolytic function of a serine protease contained in Vv-OMVs may contribute to pathogenicity of V. vulnificus by assisting bacterial translocation. This study reveals a new pathogenic mechanism during V. vulnificus infections. J. Med. Invest. 71 : 102-112, February, 2024.
Topics: Vibrio vulnificus; Humans; Extracellular Vesicles; Hemolysin Proteins; L-Lactate Dehydrogenase; Bacterial Outer Membrane; Epithelial Cells
PubMed: 38735705
DOI: 10.2152/jmi.71.102 -
Microbiological Research Aug 2024Vibrio parahaemolyticus is the leading bacterial cause of gastroenteritis associated with seafood consumption worldwide. Not all members of the species are thought to be...
Vibrio parahaemolyticus is the leading bacterial cause of gastroenteritis associated with seafood consumption worldwide. Not all members of the species are thought to be pathogenic, thus identification of virulent organisms is essential to protect public health and the seafood industry. Correlations of human disease and known genetic markers (e.g. thermostable direct hemolysin (TDH), TDH-related hemolysin (TRH)) appear complex. Some isolates recovered from patients lack these factors, while their presence has become increasingly noted in isolates recovered from the environment. Here, we used whole-genome sequencing in combination with mammalian and insect models of infection to assess the pathogenic potential of V. parahaemolyticus isolated from European Atlantic shellfish production areas. We found environmental V. parahaemolyticus isolates harboured multiple virulence-associated genes, including TDH and/or TRH. However, carriage of these factors did not necessarily reflect virulence in the mammalian intestine, as an isolate containing TDH and the genes coding for a type 3 secretion system (T3SS) 2α virulence determinant, appeared avirulent. Moreover, environmental V. parahaemolyticus lacking TDH or TRH could be assigned to groups causing low and high levels of mortality in insect larvae, with experiments using defined bacterial mutants showing that a functional T3SS1 contributed to larval death. When taken together, our findings highlight the genetic diversity of V. parahaemolyticus isolates found in the environment, their potential to cause disease and the need for a more systematic evaluation of virulence in diverse V. parahaemolyticus to allow better genetic markers.
Topics: Vibrio parahaemolyticus; Animals; Virulence; Europe; Hemolysin Proteins; Virulence Factors; Vibrio Infections; Bacterial Proteins; Bacterial Toxins; Humans; Whole Genome Sequencing; Phenotype; Shellfish; Larva; Type III Secretion Systems; Genome, Bacterial; Seafood
PubMed: 38735242
DOI: 10.1016/j.micres.2024.127744 -
International Journal of Systematic and... May 2024Two Gram-stain-negative, rod-shaped bacteria, designated as strains KJ10-1 and KJ40-1, were isolated from marine brown algae. Both strains were catalase-positive,...
Two Gram-stain-negative, rod-shaped bacteria, designated as strains KJ10-1 and KJ40-1, were isolated from marine brown algae. Both strains were catalase-positive, oxidase-positive, and facultative aerobic. Strain KJ10-1 exhibited optimal growth at 25 °C, pH 7.0, and 3 % NaCl, whereas strain KJ40-1 showed optimal growth at 25 °C, pH 7.0, and 2 % NaCl. The respiratory quinones of strain KJ10-1 were ubiquinone-8, ubiquinone-7, menaquinone-7, and methylated menaquinone-7, while the respiratory quinone of strain KJ40-1 was only ubiquinone-8. As major fatty acids, strain KJ10-1 contained C, C ω8, iso-C, and summed feature 3 (C 7 and/or C 6) and strain KJ40-1 contained C and summed features 3 and 8 (C 7 and/or C 6). The major polar lipids in strain KJ10-1 were phosphatidylethanolamine, phosphatidylglycerol, and an unidentified aminolipid, whereas those in strain KJ40-1 were phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The DNA G+C contents of strains KJ10-1 and KJ40-1 were 42.1 and 40.8 mol%, respectively. Based on 16S rRNA gene sequences, strains KJ10-1 and KJ40-1 exhibited the closest relatedness to MMS16-UL250 (98.6 %) and S-1 (95.4 %), respectively. Phylogenetic analyses, based on both 16S rRNA and 92 housekeeping genes, showed that the strains formed distinct phylogenic lineages within the genera and . Digital DNA-DNA hybridization and orthologous average nucleotide identity values between strain KJ10-1 and other species, as well as between strain KJ40-1 and other species, were below the thresholds commonly accepted for prokaryotic species delineation. Based on the phenotypic, chemotaxonomic, and phylogenetic data, strains KJ10-1 and KJ40-1 represent novel species of the genera and , respectively, for which the names sp. nov. and sp. nov. are proposed, respectively. The type strains of and are KJ10-1 (=KACC 22589=JCM 35409) and KJ40-1 (=KACC 22588=JCM 35410), respectively.
Topics: RNA, Ribosomal, 16S; Base Composition; Phylogeny; Fatty Acids; DNA, Bacterial; Bacterial Typing Techniques; Sequence Analysis, DNA; Vibrio; Ubiquinone; Shewanella; Phaeophyceae; Vitamin K 2; Phospholipids; Nucleic Acid Hybridization; Seawater
PubMed: 38728177
DOI: 10.1099/ijsem.0.006378 -
Biomedical and Environmental Sciences :... Apr 2024
Topics: Vibrio parahaemolyticus; Regulon; Bacterial Proteins; Type VI Secretion Systems; Gene Expression Regulation, Bacterial; Transcription, Genetic
PubMed: 38727168
DOI: 10.3967/bes2024.049 -
Applied and Environmental Microbiology Jun 2024Cells of colonize the light organ of , providing the squid bioluminescence in exchange for nutrients and protection. The bacteria encounter DNA-rich mucus throughout...
Corrected and republished from: " Possesses Xds and Dns Nucleases That Differentially Influence Phosphate Scavenging, Aggregation, Competence, and Symbiotic Colonization of Squid".
Cells of colonize the light organ of , providing the squid bioluminescence in exchange for nutrients and protection. The bacteria encounter DNA-rich mucus throughout their transition to a symbiotic lifestyle, leading us to hypothesize a role for nuclease activity in the colonization process. In support of this, we detected abundant extracellular nuclease activity in growing cells of . To discover the gene(s) responsible for this activity, we screened a transposon mutant library for nuclease-deficient strains. Interestingly, only one strain, whose transposon insertion mapped to nuclease gene , showed a complete loss of nuclease activity in our screens. A database search revealed that is homologous to the nuclease-encoding gene in . However, strains lacking eventually revealed slight nuclease activity on plates upon prolonged incubation. This led us to hypothesize that a second secreted nuclease, identified through a database search as , a homolog of , might be responsible for the residual nuclease activity. Here, we show that Xds and/or Dns are involved in essential aspects of biology, including natural transformation, aggregation, and phosphate scavenging. Furthermore, strains lacking either nuclease were outcompeted by the wild type for squid colonization. Understanding the specific role of nuclease activity in the squid colonization process represents an intriguing area of future research.IMPORTANCEFrom soil and water to host-associated secretions such as mucus, environments that bacteria inhabit are awash in DNA. Extracellular DNA (eDNA) is a nutritious resource that microbes dedicate significant energy to exploit. Calcium binds eDNA to promote cell-cell aggregation and horizontal gene transfer. eDNA hydrolysis impacts the construction of and dispersal from biofilms. Strategies in which pathogens use nucleases to avoid phagocytosis or disseminate by degrading host secretions are well-documented; significantly less is known about nucleases in mutualistic associations. This study describes the role of nucleases in the mutualism between and its squid host . We find that nuclease activity is an important determinant of colonization in , broadening our understanding of how microbes establish and maintain beneficial associations.
Topics: Aliivibrio fischeri; Decapodiformes; Animals; Symbiosis; Phosphates; Bacterial Proteins; Deoxyribonucleases
PubMed: 38712952
DOI: 10.1128/aem.00328-24 -
Frontiers in Immunology 2024Vibriosis, caused by , seriously affects the health of fish, shellfish, and shrimps, causing large economic losses. Teleosts are represent the first bony vertebrates...
Vibriosis, caused by , seriously affects the health of fish, shellfish, and shrimps, causing large economic losses. Teleosts are represent the first bony vertebrates with both innate and adaptive immune responses against pathogens. Aquatic animals encounter hydraulic pressure and more pathogens, compared to terrestrial animals. The skin is the first line of defense in fish, constituting the skin-associated lymphoid tissue (SALT), which belongs to the main mucosa-associated lymphoid tissues (MALT). However, little is known about the function of immunity related proteins in fish. Therefore, this study used iTRAQ (isobaric tags for relative and absolute quantitation) to compare the skin proteome between the resistant and susceptible families of . The protein integrin beta-2, the alpha-enolase isoform X1, subunit B of V-type proton ATPase, eukaryotic translation initiation factor 6, and ubiquitin-like protein ISG15, were highly expressed in the resistant family. The 16S sequencing of the skin tissues of the resistant and susceptible families showed significant differences in the microbial communities of the two families. The protein-microbial interaction identified ten proteins associated with skin microbes, including immunoglobulin heavy chain gene (IGH), B-cell lymphoma/leukemia 10 (BCL10) and pre-B-cell leukemia transcription factor 1 isoform X2 (PBX2). This study highlights the interaction between skin proteins and the microbial compositions of and provides new insights into understanding aquaculture breeding research.
Topics: Animals; Skin; Fish Diseases; Disease Resistance; Vibrio Infections; Flatfishes; Microbiota; Vibrio; Fish Proteins; Proteome; Proteomics
PubMed: 38711504
DOI: 10.3389/fimmu.2024.1352469 -
Communications Biology May 2024DNA replication is essential for the proliferation of all cells. Bacterial chromosomes are replicated bidirectionally from a single origin of replication, with...
DNA replication is essential for the proliferation of all cells. Bacterial chromosomes are replicated bidirectionally from a single origin of replication, with replication proceeding at about 1000 bp per second. For the model organism, Escherichia coli, this translates into a replication time of about 40 min for its 4.6 Mb chromosome. Nevertheless, E. coli can propagate by overlapping replication cycles with a maximum short doubling time of 20 min. The fastest growing bacterium known, Vibrio natriegens, is able to replicate with a generation time of less than 10 min. It has a bipartite genome with chromosome sizes of 3.2 and 1.9 Mb. Is simultaneous replication from two origins a prerequisite for its rapid growth? We fused the two chromosomes of V. natriegens to create a strain carrying one chromosome with a single origin of replication. Compared to the parental, this strain showed no significant deviation in growth rate. This suggests that the split genome is not a prerequisite for rapid growth.
Topics: Vibrio; Chromosomes, Bacterial; DNA Replication; Genome, Bacterial; Replication Origin; DNA, Bacterial
PubMed: 38698198
DOI: 10.1038/s42003-024-06234-1