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Environmental Pollution (Barking, Essex... Aug 2024The impact of leachates from micronized beached plastics of the Mediterranean Sea and Atlantic Ocean on coastal marine ecosystems was investigated by using a...
The impact of leachates from micronized beached plastics of the Mediterranean Sea and Atlantic Ocean on coastal marine ecosystems was investigated by using a multidisciplinary approach. Chemical analysis and ecotoxicological tests on phylogenetically distant species were performed on leachates from the following plastic categories: bottles, pellets, hard plastic (HP) containers, fishing nets (FN) and rapido trawling rubber (RTR). The bacteria Alivibrio fischeri, the nauplii of the crustaceans Amphibalanus amphitrite and Acartia tonsa, the rotifer Brachionus plicatilis, the embryos of the sea urchin Paracentrotus lividus, the ephyrae of the jellyfish Aurelia sp. and the larvae of the medaka Oryzias latipes were exposed to different concentrations of leachates to evaluate lethal and sub-lethal effects. Thirty-one additives were identified in the plastic leachates; benzophenone, benzyl butyl phthalate and ethylparaben were present in all leachates. Ecotoxicity of leachates varied among plastic categories and areas, being RTR, HP and FN more toxic than plastic bottles and pellets to several marine invertebrates. The ecotoxicological results based on 13 endpoints were elaborated within a quantitative weight of evidence (WOE) model, providing a synthetic hazard index for each data typology, before their integrations in an environmental risk index. The WOE assigned a moderate and slight hazard to organisms exposed to leachates of FN and HP collected in the Mediterranean Sea respectively, and a moderate hazard to leachates of HP from the Atlantic Ocean. No hazard was found for pellet, bottles and RTR. These findings suggest that an integrated approach based on WOE on a large set of bioassays is recommended to get a more reliable assessment of the ecotoxicity of beached-plastic leachates. In addition, the additives leached from FN and HP should be further investigated to reduce high concentrations and additive types that could impact marine ecosystem health.
Topics: Animals; Plastics; Water Pollutants, Chemical; Mediterranean Sea; Aquatic Organisms; Invertebrates; Aliivibrio fischeri; Environmental Monitoring; Atlantic Ocean; Ecotoxicology; Vertebrates; Oryzias; Paracentrotus
PubMed: 38801877
DOI: 10.1016/j.envpol.2024.124233 -
Applied Microbiology and Biotechnology May 2024Isolates of Vibrio splendidus are ubiquitously presented in various marine environments, and they can infect diverse marine culture animals, leading to high mortality...
Isolates of Vibrio splendidus are ubiquitously presented in various marine environments, and they can infect diverse marine culture animals, leading to high mortality and economic loss. Therefore, a control strategy of the infection caused by V. splendidus is urgently recommended. Tryptanthrin is a naturally extracted bioactive chemical with antimicrobial activity to other bacteria. In this study, the effects of tryptanthrin on the bacterial growth and virulence-related factors of one pathogenic strain V. splendidus AJ01 were determined. Tryptanthrin (10 μg/mL) could completely inhibit the growth of V. splendidus AJ01. The virulence-related factors of V. splendidus AJ01 were affected in the presence of tryptanthrin. Tryptanthrin resulted an increase in biofilm formation, but lead to reduction in the motility and hemolytic activity of V. splendidus cells. In the cells treated with tryptanthrin, two distinctly differentially expressed extracellular proteins, proteases and flagellum, were identified using SDS-PAGE combined with LC-MS. Real-time reverse transcriptase PCR confirmed that the genes involved in the flagellar formation and hemolysin decreased, whereas specific extracellular proteases and the genes involved in the biofilm formation were upregulated. Two previously annotated luxO genes were cloned, and their expression levels were analyzed at different cell densities. Molecular docking was performed to predict the interaction between LuxO and ATP/tryptanthrin. The two sigma-54-dependent transcriptional regulators showed similar ATP or tryptanthrin binding capacity but with different sites, and the direct competitive binding between ATP and tryptanthrin was present only in their binding to LuxO. These results indicated that tryptanthrin can be used as a bactericide of V. splendidus by inhibiting the growth, bacterial flagella, and extracellular proteases, but increasing the biofilm. Sigma-54-dependent transcriptional regulator, especially the quorum sensing regulatory protein LuxO, was determined to be the potential target of tryptanthrin. KEY POINTS: • Tryptanthrin inhibited the growth of V. splendidus in a dose-dependent manner. • The effect of tryptanthrin on the virulence factors of V. splendidus was characterized. • LuxO was the potential target for tryptanthrin based on molecular docking.
Topics: Biofilms; Vibrio; Anti-Bacterial Agents; Quinazolines; Virulence Factors; Molecular Docking Simulation; Bacterial Proteins; Flagella; Hemolysis; Animals; Microbial Sensitivity Tests; Gene Expression Regulation, Bacterial
PubMed: 38789572
DOI: 10.1007/s00253-024-13158-7 -
Marine Drugs May 2024Alginate oligosaccharides (AOS), products of alginate degradation by endotype alginate lyases, possess favorable biological activities and have broad applications....
Alginate oligosaccharides (AOS), products of alginate degradation by endotype alginate lyases, possess favorable biological activities and have broad applications. Although many have been reported, alginate lyases with homogeneous AOS products and secretory production by an engineered host are scarce. Herein, the alginate lyase AlyC7 from sp. C42 was characterized as a trisaccharide-producing lyase exhibiting high activity and broad substrate specificity. With PelB as the signal peptide and 500 mM glycine as the additive, the extracellular production of AlyC7 in reached 1122.8 U/mL after 27 h cultivation in Luria-Bertani medium. The yield of trisaccharides from sodium alginate degradation by the produced AlyC7 reached 758.6 mg/g, with a purity of 85.1%. The prepared AOS at 20 μg/mL increased the root length of lettuce, tomato, wheat, and maize by 27.5%, 25.7%, 9.7%, and 11.1%, respectively. This study establishes a robust foundation for the industrial and agricultural applications of AlyC7.
Topics: Polysaccharide-Lyases; Trisaccharides; Escherichia coli; Vibrio; Substrate Specificity; Alginates; Zea mays; Oligosaccharides
PubMed: 38786621
DOI: 10.3390/md22050230 -
Scientific Reports May 2024Climate change and disease threaten shrimp farming. Here, we studied the beneficial properties of a phytogenic formulation, Shrimp Best (SB), in whiteleg shrimp....
Climate change and disease threaten shrimp farming. Here, we studied the beneficial properties of a phytogenic formulation, Shrimp Best (SB), in whiteleg shrimp. Functional studies showed that SB dose-dependently increased shrimp body weight and decreased feed conversion ratio. We found that SB protected against Vibrio parahaemolyticus as evidenced by survival rate, bacterial load, and hepatopancreatic pathology in shrimp. Finally, we explored the likely mechanism by which SB affects growth performance and vibriosis in shrimp. The 16S rRNA sequencing data showed that SB increased 6 probiotic genera and decreased 6 genera of pathogenic bacteria in shrimp. Among these, SB increased the proportion of Lactobacillus johnsonii and decreased that of V. parahaemolyticus in shrimp guts. To dissect the relationship among SB, Lactobacillus and Vibrio, we investigated the in vitro regulation of Lactobacillus and Vibrio by SB. SB at ≥ 0.25 μg/mL promoted L. johnsonii growth. Additionally, L. johnsonii and its supernatant could inhibit V. parahaemolyticus. Furthermore, SB could up-regulate five anti-Vibrio metabolites of L. johnsonii, which caused bacterial membrane destruction. In parallel, we identified 3 fatty acids as active compounds from SB. Overall, this work demonstrated that SB improved growth performance and vibriosis protection in shrimp via the regulation of gut microbiota.
Topics: Animals; Penaeidae; Vibrio parahaemolyticus; Vibrio Infections; Lactobacillus; RNA, Ribosomal, 16S; Vibrio; Probiotics
PubMed: 38773245
DOI: 10.1038/s41598-024-62436-x -
BioRxiv : the Preprint Server For... May 2024Marine bacteria experience fluctuations in osmolarity that they must adapt to, and most bacteria respond to high osmolarity by accumulating compatible solutes also known...
UNLABELLED
Marine bacteria experience fluctuations in osmolarity that they must adapt to, and most bacteria respond to high osmolarity by accumulating compatible solutes also known as osmolytes. The osmotic stress response and compatible solutes used by the coral and oyster pathogen were unknown. In this study, we showed that to alleviate osmotic stress biosynthesized glycine betaine (GB) and transported into the cell choline, GB, ectoine, dimethylglycine, and dimethylsulfoniopropionate, but not -inositol. -inositol is a stress protectant and a signaling molecule that is biosynthesized and used by algae. Bioinformatics identified -inositol ( ) catabolism clusters in and other and species. Growth pattern analysis demonstrated that utilized -inositol as a sole carbon source, with a short lag time of 3 h. An deletion mutant, which encodes an inositol dehydrogenase, was unable to grow on -inositol. Within the clusters were an MFS-type ( and an ABC-type ( transporter and analyses showed that both transported -inositol. IolG and IolA phylogeny among species showed different evolutionary histories indicating multiple acquisition events. Outside of , IolG was most closely related to IolG from a small group of fish and human pathogens and species. However, IolG from hypervirulent strains clustered with IolG from and divergently from and plant pathogens. The cluster was also present within and of which many species were associated with marine flora and fauna.
IMPORTANCE
Host associated bacteria such as encounter competition for nutrients and have evolved metabolic strategies to better compete for food. Emerging studies show that -inositol is exchanged in the coral-algae symbiosis, is likely involved in signaling, but is also an osmolyte in algae. The bacterial consumption of -inositol could contribute to a breakdown of the coral-algae symbiosis during thermal stress or disrupt the coral microbiome. Phylogenetic analyses showed that the evolutionary history of -inositol metabolism is complex, acquired multiple times in but acquired once in many bacterial plant pathogens. Further analysis also showed that a conserved cluster is prevalent among many marine species (commensals, mutualists, and pathogens) associated with marine flora and fauna, algae, sponges, corals, molluscs, crustaceans, and fish.
PubMed: 38766061
DOI: 10.1101/2024.01.16.575920 -
Analytical Chemistry May 2024Microbial biofilms represent an important lifestyle for bacteria and are dynamic three-dimensional structures. Cyclic dimeric guanosine monophosphate (c-di-GMP) is a...
Microbial biofilms represent an important lifestyle for bacteria and are dynamic three-dimensional structures. Cyclic dimeric guanosine monophosphate (c-di-GMP) is a ubiquitous signaling molecule that is known to be tightly regulated with biofilm processes. While measurements of global levels of c-di-GMP have proven valuable toward understanding the genetic control of c-di-GMP production, there is a need for tools to observe the local changes of c-di-GMP production in biofilm processes. We have developed a label-free method for the direct detection of c-di-GMP in microbial colony biofilms using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). We applied this method to the enteric pathogen , the marine symbiont , and the opportunistic pathogen PA14 and detected spatial and temporal changes in c-di-GMP signal that accompanied genetic alterations in factors that synthesize and degrade the compound. We further demonstrated how this method can be simultaneously applied to detect additional metabolites of interest from a single sample.
Topics: Cyclic GMP; Biofilms; Pseudomonas aeruginosa; Vibrio cholerae; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Aliivibrio fischeri
PubMed: 38752543
DOI: 10.1021/acs.analchem.3c04687 -
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