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Marine Biotechnology (New York, N.Y.) Feb 2024Alternative prophylactic strategies to limit farm animal infection are needed in order to avoid the use of antibiotics. Anti-bacterial and immunostimulatory properties...
Alternative prophylactic strategies to limit farm animal infection are needed in order to avoid the use of antibiotics. Anti-bacterial and immunostimulatory properties of bioactive compounds are of great interest in aquaculture. Marine derived polysaccharides, such as chitosan and ulvan, together with nanotechnology, have become the focus of attention in the scientific community due to their wide range of biological properties. In this work, chitosan and ulvan-loaded chitosan nanoparticles (referred as CS-TPP NPs and CS-UL-TPP NPs, respectively), obtained by the ionotropic gelation method, had round shape, and the mean sizes were 137.00 ± 5.44 and 325.50 ± 4.95 nm, respectively. No study about the anti-bacterial activity of both types of NPs against Photobacterium damselae subsp. piscicida, an important fish pathogen, has been reported so far. Furthermore, the potential immunostimulatory effects of CS-UL-TPP NPs after oral administration in fish have not yet been evaluated. The percentage of bacterial inhibition against P. damselae subsp. piscicida was determined through in vitro assays, and it was significantly higher in CS-UL-TPP NPs than in CS-TPP NPs at concentrations below 0.03 mg mL. The effects on the immune system of CS-TPP and CS-UL-TPP NPs were evaluated in Solea senegalensis juveniles at 30 days after oral administration. Lysozyme activity as well as gene expression levels of il1b, il6, hamp1, tf and c3 was significantly higher in CS-UL-TPP NP-treated groups than in the controls, and no significant differences were observed in CS-TPP NP-treated groups. Thus, ulvan extracted from the macroalgae Ulva ohnoi could improve anti-bacterial and immunostimulant properties of CS-TPP NPs thereby making them suitable to be used as vaccine adjuvant or as immunostimulant.
Topics: Animals; Chitosan; Nanoparticles; Aquaculture; Adjuvants, Immunologic; Photobacterium; Polysaccharides
PubMed: 38110743
DOI: 10.1007/s10126-023-10272-x -
Immunity, Inflammation and Disease Jan 2024This study was designed to analyze the structural characteristics of the intestinal flora of elderly Uygur patients with sarcopenia, thereby providing new ideas for...
OBJECTIVE
This study was designed to analyze the structural characteristics of the intestinal flora of elderly Uygur patients with sarcopenia, thereby providing new ideas for clinical treatment.
METHODS
Firstly, fecal samples were collected from 40 elderly Uygur patients with sarcopenia (Sarcopenia group) and 40 healthy people (Control group). Next, significant differences in the intestinal flora between the two groups were analyzed based on 16S rDNA high-throughput sequencing. The linear discriminant analysis effect size (LEfSe) was used to estimate the magnitude of the effect of each component (species) abundance on the differential effect. Additionally, an analysis was also performed on the relationship between the intestinal flora and the cytokines in the peripheral blood of patients with sarcopenia.
RESULTS
The results of β diversity showed that there were differences in the structure of the intestinal flora between the two groups. Besides, the phylum level of intestinal flora between the two groups was not significantly different. However, the difference was significant in the intestinal flora at the order, family, and genus levels between the two groups. Among them, Lachnoclostridium, Photobacterium, Anaerobic Bacillus, Hydrogenophilus, and Eubacterium were enriched in the Sarcopenia group; Prevotella 9, Firmicutes FCS020 group, Streptobacillus, Aggregatibacter, Corynebacterium, Clostridium Difficile, and Haloanaerobium were enriched in the Control group. The LEfSe outcomes further showed that Lachnoclostridium was highly enriched in the Sarcopenia group; Prevotella 9 and Firmicutes FCS020 group were significantly enriched in the Control group. Furthermore, the relative abundance of Lachnoclostridium and Streptobacillus were significantly different in patients with high and low IL-6 levels.
CONCLUSION
In conclusion, Lachnoclostridium is significantly enriched in the intestines of elderly Uygur patients with sarcopenia; the increase in Lachnoclostridium abundance and the decrease in Streptobacillus abundance are associated with high levels of IL-6. Therefore, abnormal intestinal flora is related to inflammatory reflexes in patients with sarcopenia.
Topics: Aged; Humans; Gastrointestinal Microbiome; Interleukin-6; Sarcopenia; Cytokines; Feces
PubMed: 38270306
DOI: 10.1002/iid3.1097 -
FEMS Microbiology Ecology Feb 2024The skin of fish contains a diverse microbiota that has symbiotic functions with the host, facilitating pathogen exclusion, immune system priming, and nutrient...
The skin of fish contains a diverse microbiota that has symbiotic functions with the host, facilitating pathogen exclusion, immune system priming, and nutrient degradation. The composition of fish skin microbiomes varies across species and in response to a variety of stressors, however, there has been no systematic analysis across these studies to evaluate how these factors shape fish skin microbiomes. Here, we examined 1922 fish skin microbiomes from 36 studies that included 98 species and nine rearing conditions to investigate associations between fish skin microbiome, fish species, and water physiochemical factors. Proteobacteria, particularly the class Gammaproteobacteria, were present in all marine and freshwater fish skin microbiomes. Acinetobacter, Aeromonas, Ralstonia, Sphingomonas and Flavobacterium were the most abundant genera within freshwater fish skin microbiomes, and Alteromonas, Photobacterium, Pseudoalteromonas, Psychrobacter and Vibrio were the most abundant in saltwater fish. Our results show that different culturing (rearing) environments have a small but significant effect on the skin bacterial community compositions. Water temperature, pH, dissolved oxygen concentration, and salinity significantly correlated with differences in beta-diversity but not necessarily alpha-diversity. To improve study comparability on fish skin microbiomes, we provide recommendations for approaches to the analyses of sequencing data and improve study reproducibility.
Topics: Animals; Water; Phylogeny; Reproducibility of Results; Skin; Microbiota
PubMed: 38366921
DOI: 10.1093/femsec/fiae021 -
Microorganisms Sep 2023The use of antibiotics in open-water aquaculture is often unavoidable when faced with pathogens with high mortality rates. In addition, seasonal pathogen surges have...
The use of antibiotics in open-water aquaculture is often unavoidable when faced with pathogens with high mortality rates. In addition, seasonal pathogen surges have become more common and more intense over the years. Apart from the apparent cost of antibiotic treatment, it has been observed that, in aquaculture practice, the surviving fish often display measurable growth impairment. To understand the role of gut microbiota on the observed growth impairment, in this study, we follow the incidence of subsp. in a seabass commercial open-water aquaculture setting in Galaxidi (Greece). Fish around 10 months of age were fed with feed containing oxytetracycline (120 mg/kg/day) for twelve days, followed by a twelve-day withdrawal period, and another eighteen days of treatment. The fish were sampled 19 days before the start of the first treatment and one month after the end of the second treatment cycle. Sequencing of the 16S rRNA gene was used to measure changes in the gut microbiome. Overall, the gut microbiota community, even a month after treatment, was highly dysbiotic and characterized by very low alpha diversity. High abundances of alkalophilic bacteria in the post-antibiotic-treated fish indicated a rise in pH that was coupled with a significant increase in gut parasites. This study's results indicate that oxytetracycline (OTC) treatment causes persistent dysbiosis even one month after withdrawal and provides a more suitable environment for an increase in parasites. These findings highlight the need for interventions to restore a healthy and protective gut microbiome.
PubMed: 37764146
DOI: 10.3390/microorganisms11092302 -
Food Research International (Ottawa,... Jan 2024Fresh fish is a highly perishable product and is easily spoiled by microbiological activity and chemical oxidation of lipids. However, microbial spoilage is the main...
Fresh fish is a highly perishable product and is easily spoiled by microbiological activity and chemical oxidation of lipids. However, microbial spoilage is the main factor linked with the rapid fish sensorial degradation due to the action of specific spoilage organisms (SSOs) that have the ability to dominate over other microorganisms and produce metabolites responsible for off-flavours. We explored the microbial dynamics in fresh anchovies stored in different packaging (air, modified atmosphere, under vacuum) and temperatures (0, 4 and 10 °C) using shotgun metagenomics, highlighting the selection of different microbial species according to the packaging type. Indeed, Pseudoalteromonas nigrifaciens, Psychrobacter cryohalolentis and Ps. immobilis, Pseudomonas deceptionensis and Vibrio splendidus have been identified as the main SSOs in aerobically stored anchovies, while Shewanella baltica, Photobacterium iliopiscarium, Ps. cryohalolentis and Ps. immobilis prevailed in VP and MAP. In addition, we identified the presence of spoilage-associated genes, leading to the potential production of biogenic amines and different off-flavors (HS, TMA). In particular, the abundance of microbial genes leading to BA biosynthesis increased at higher storage temperature, while those related to HS and TMA production were enriched in aerobically and VP packed anchovies, suggesting that MAP could be an effective strategy in delaying the production of these compounds. Finally, we provided evidence of the presence of a wide range of antibiotic resistance genes conferring resistance to different classes of antibiotic (β-lactams, tetracyclines, polymyxins, trimethoprims and phenicols) and highlighted that storage at higher temperature (4 and 10 °C) boosted the abundance of ARG-carrying taxa, especially in aerobically and MAP packed fish.
Topics: Animals; Food Packaging; Anti-Bacterial Agents; Food Microbiology; Food Preservation; Genomics; Microbiota
PubMed: 38129066
DOI: 10.1016/j.foodres.2023.113788 -
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 -
Brazilian Journal of Microbiology :... Mar 2024The frosty polar environment houses diverse habitats mostly driven by psychrophilic and psychrotolerant microbes. Along with traditional cultivation methods,...
The frosty polar environment houses diverse habitats mostly driven by psychrophilic and psychrotolerant microbes. Along with traditional cultivation methods, next-generation sequencing technologies have become common for exploring microbial communities from various extreme environments. Investigations on glaciers, ice sheets, ponds, lakes, etc. have revealed the existence of numerous microorganisms while details of microbial communities in the Arctic fjords remain incomplete. The current study focuses on understanding the bacterial diversity in two Arctic fjord sediments employing the 16S rRNA gene metabarcoding and its comparison with previous studies from various Arctic habitats. The study revealed that Proteobacteria was the dominant phylum from both the fjord samples followed by Bacteroidetes, Planctomycetes, Firmicutes, Actinobacteria, Cyanobacteria, Chloroflexi and Chlamydiae. A significant proportion of unclassified reads derived from bacteria was also detected. Psychrobacter, Pseudomonas, Acinetobacter, Aeromonas, Photobacterium, Flavobacterium, Gramella and Shewanella were the major genera in both the fjord sediments. The above findings were confirmed by the comparative analysis of fjord metadata with the previously reported (secondary metadata) Arctic samples. This study demonstrated the potential of 16S rRNA gene metabarcoding in resolving bacterial composition and diversity thereby providing new in situ insights into Arctic fjord systems.
Topics: RNA, Ribosomal, 16S; Geologic Sediments; Estuaries; Bacteria; Microbiota; Arctic Regions
PubMed: 38175355
DOI: 10.1007/s42770-023-01217-6 -
Microorganisms Feb 2024Spotted sea bass () is a high-economic-value aquacultural fish widely distributed in the coastal and estuarine areas of East Asia. In August 2020, a sudden outbreak of...
Spotted sea bass () is a high-economic-value aquacultural fish widely distributed in the coastal and estuarine areas of East Asia. In August 2020, a sudden outbreak of disease accompanied by significant mortality was documented in reared in marine cage cultures located in Nanhuang island, Yantai, China. Two coinfected bacterial strains, namely, NH-LM1 and NH-LM2, were isolated from the diseased for the first time. Through phylogenetic tree analysis, biochemical characterization, and genomic investigation, the isolated bacterial strains were identified as and subsp. , respectively. The genomic analysis revealed that possesses two circular chromosomes and six plasmids, while subsp. possesses two circular chromosomes and two plasmids. Furthermore, pathogenic genes analysis identified 587 and 484 genes in and subsp. , respectively. Additionally, drug-sensitivity testing demonstrated both and subsp. exhibited sensitivity to chloramphenicol, ciprofloxacin, ofloxacin, orfloxacin, minocycline, doxycycline, tetracycline, and ceftriaxone. Moreover, antibiotic resistance genes were detected in the plasmids of both strains. Extracellular product (ECP) analysis demonstrated that both and subsp. can produce hemolysin and amylase, while additionally can produce caseinase and esterase. Furthermore, infected fish displayed severe histopathological alterations, including infiltration of lymphocytes, cellular degeneration and necrosis, and loose aggregation of cells. Artificial infection assays determined that the LD of subsp. was 3 × 10 CFU/g, while the LD of was too low to be accurately evaluated. Furthermore, the dual infection of and subsp. elicits a more rapid and pronounced mortality rate compared to single challenge, thereby potentially exacerbating the severity of the disease through synergistic effects. Ultimately, our findings offer compelling evidence for the occurrence of coinfections involving and subsp. in , thereby contributing to the advancement of diagnostic and preventative measures for the associated disease.
PubMed: 38543554
DOI: 10.3390/microorganisms12030503 -
Applied and Environmental Microbiology Jun 2024Marine bacteria experience fluctuations in osmolarity that they must adapt to, and most bacteria respond to high osmolarity by accumulating compatible solutes also known...
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.IMPORTANCEHost 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: 38874337
DOI: 10.1128/aem.00920-24 -
MicrobiologyOpen Aug 2023Gene inactivation studies are critical in pathogenic bacteria, where insights into species biology can guide the development of vaccines and treatments. Allelic exchange...
Transforming the untransformable with knockout minicircles: High-efficiency transformation and vector-free allelic exchange knockout in the fish pathogen Photobacterium damselae.
Gene inactivation studies are critical in pathogenic bacteria, where insights into species biology can guide the development of vaccines and treatments. Allelic exchange via homologous recombination is a generic method of targeted gene editing in bacteria. However, generally applicable protocols are lacking, and suboptimal approaches are often used for nonstandard but epidemiologically important species. Photobacterium damselae subsp. piscicida (Pdp) is a primary pathogen of fish in aquaculture and has been considered hard to transform since the mid-1990s. Consequently, conjugative transfer of RK2/RP4 suicide vectors from Escherichia coli S17-1/SM10 donor strains, a system prone to off-target mutagenesis, was used to deliver the allelic exchange DNA in previous studies. Here we have achieved efficient electrotransformation in Pdp using a salt-free highly concentrated sucrose solution, which performs as a hypertonic wash buffer, cryoprotectant, and electroporation buffer. High-efficiency transformation has enabled vector-free mutagenesis for which we have employed circular minimalistic constructs (knockout minicircles) containing only allelic exchange essentials that were generated by Gibson assembly. Preparation of competent cells using sucrose and electroporation/integration of minicircles had virtually no detectable off-target promutagenic effect. In contrast, a downstream sacB selection apparently induced several large deletions via mobilization of transposable elements. Electroporation of minicircles into sucrose-treated cells is a versatile broadly applicable approach that may facilitate allelic exchange in a wide range of microbial species. The method permitted inactivation of a primary virulence factor unique to Pdp, apoptogenic toxin AIP56, demonstrating the efficacy of minicircles for difficult KO targets located on the high copy number of small plasmids.
Topics: Animals; Photobacterium; Electroporation; Fishes
PubMed: 37642481
DOI: 10.1002/mbo3.1374