Vibrio Strains Research Articles

Induction of transgenerational innate immune memory against Vibrio infections in a brine shrimp (Artemia franciscana) model

The occurrence of transgenerational innate immune memory in invertebrates possibly offers an opportunity for the creation of offspring with increased resistance against infectious diseases. Shrimps, being invertebrates rely on their innate immune system as the main defence mechanism to combat invading pathogens. Thus, creating transgenerational innate immune memory could be used for disease prevention in shrimp farming. However, the mechanisms behind the induction of transgenerational innate immune memory and the creation of a broad spectrum protective immune memory are still not fully understood. Here, the creation of transgenerational innate immune memory and the mechanisms involved were studied using the brine shrimp (Artemia franciscana) as a model for shrimps. Hereto, a parental generation was primed by exposure to a live or dead Vibrio parahaemolyticus PV1 while another parental generation was primed with live or dead Vibrio campbellii LMG21363. Both Vibrio strains are known to cause diseases in farmed shrimps, resulting in significant economic losses. Axenic larvae of three subsequent generations were exposed either to the homologous or heterologous (viable) Vibrio species and their survival was recorded. In general, progenies from primed F0 parents developed innate immune memory as compared to offspring of non-primed control F0 parents as they were significantly protected against a subsequent Vibrio infection. Protection in the infected offspring was more pronounced when they were infected with the homologous Vibrio strain. Disease resistance was associated with significantly increased transcription of especially peroxinectin (pxn), prophenoloxidase (proPO), lipopolysaccharide and β-1,3-glucan-binding protein (LGBP), high mobility group box 1 (HMGB1) and heat shock protein 90 (hsp90) genes and significant changes in histone H3 and H4 acetylation and m6A RNA methylation. Overall, results might lead to procedures at shrimp brood stock level for parental conditioning and creation of transgenerational innate immune memory in offspring.

Membrane-disruptive engineered peptide amphiphiles restrain the proliferation of penicillins and cephalosporins resistant Vibrio alginolyticus and Vibrio parahaemolyticus in instant jellyfish

Over 1 billion people rely on seafood as their primary source of protein and Vibrio spp. is the most important pathogen of foodborne disease outbreak related to consumption of seafood. Moreover, the rise of drug-resistant Vibrio strains further increases the difficulty of clinical treatment. However, there is no food preservative available to combat drug-resistant Vibrio spp. in seafood. In this study, we designed and synthesized three novel antibacterial peptides (ABPs) derived from zp3 (GIIAGIIIKIKK-NH 2 ). One of them, 3 K 5 K 7 G (GIKAKIGIKIKK-NH 2 ), had bioactivity against all tested penicillins and cephalosporins resistant Vibrio with minimal inhibitory concentration (MIC) values at 2–16 μM, performing better than its template zp3 . 3 K 5 K 7 G demonstrated favourable antibacterial capability in instant jellyfish, killing more than 99% Vibrio alginolyticus cells after 64 μM treatment for 4 h. Peptide 3 K 5 K 7 G could disrupt the cell membrane, resulting in rapid membrane potential dissipation. Next, this molecule could penetrate inside cytoplasm and further bind with DNA. Importantly, 3 K 5 K 7 G showed low cytotoxicity to mammalian cells (95% Vero cells survived in the presence of 160 μM 3 K 5 K 7 G ). Collectively, 3 K 5 K 7 G has the potential to be developed into a promising food-grade antibacterial additive, especially against those resistant Vibrio spp. in seafood. • 3 K 5 K 7 G performed better antibacterial activity than its template zp3 with α-helix structure. • 3 K 5 K 7 G had MIC values at 2–16 μM to penicillins and cephalosporins resistant Vibrio. • 3 K 5 K 7 G killed more than 99% V. alginolyticus in instant jellyfish after 4 h treatment. • 3 K 5 K 7 G disrupted the cell membrane, resulting in rapid membrane potential dissipation. • 3 K 5 K 7 G had low cytotoxicity to mammalian cells.

Isolation and determination of Vibrio spp. pathogen from Sciaenops ocellatus suffering from hemorrhagic disease under cage culture in Vietnam

This study was carried out to isolate and determine the Vibrio spp. from the Red drum fish (Sciaenops ocellatus) suffering from the hemorrhagic disease in Vietnam. In this study, 18 strains of Vibrio bacteria were identified from 27 samples of Red drum fish. The isolated bacterial strains were identified with the 16S rRNA sequencing method and checked for morphological, physiological, and biochemical characteristics by using the API 20E KIT. Results of the study revealed the presence of twelve strains of V. alginolyticus, three strains of V. fluvialis, and three strains of V. orientalis. All Vibrio strains have gene similarities with those on the Genbank ranging from 98.05 to 100%. The biochemical characteristics of these 18 isolates were similar and these are susceptible to tetracycline and doxycycline and entirely resistant to ampicillin, amoxicillin, and erythromycin.

GC-MS Profiling, Vibriocidal, Antioxidant, Antibiofilm, and Anti-Quorum Sensing Properties of Carum carvi L. Essential Oil: In Vitro and In Silico Approaches.

The main objectives of the present study were to investigate anti-Vibrio spp., antibiofilms, and anti-quorum-sensing (anti-QS) properties of caraway essential oil in relation to their phytochemical composition. The results obtained show the identification of twelve compounds, with carvone (58.2%) and limonene (38.5%) being the main ones. The obtained essential oil (EO) is particularly active against all Vibrio spp. species, with bacteriostatic action against all tested strains (MBC/MIC ratio ≥ 4) and with inhibition zones with high diameters of growth, ranging from 8.66 ± 0.58 mm for V. furnisii ATCC 35016 to 37.33 ± 0.58 mm for V. alginolyticus ATCC 17749. Caraway essential oil (Carvone/limonene chemotype) exhibits antioxidant activities by using four tests (DPPH = 15 ± 0.23 mg/mL; reducing power = 7.8 ± 0.01 mg/mL; β-carotene = 3.9 ± 0.025 mg/mL; chelating power = 6.8 ± 0.05 mg/mL). This oil is particularly able to prevent cell-to-cell communication by inhibiting swarming motility, production of elastase and protease in Pseudomonas aeruginosa PAO1, and violacein production in C. violaceum in a concentration-dependent manner. A molecular docking approach shows good interaction of the identified bioactive molecules in caraway EO, with known target enzymes involved in antioxidant, antibacterial, and anti-QS activities having high binding energy. Overall, the obtained results highlight the possible use of caraway essential oil against pathogenic Vibrio species and to attenuate the secretion of virulence-related factors controlled by QS systems in Gram-negative bacteria. Therefore, this oil can be used by food industries to prevent biofilm formation on abiotic surfaces by Vibrio strains.

Dietary supplementation of Bacillus velezensis improves Vibrio anguillarum clearance in European sea bass by activating essential innate immune mechanisms

Bacillus spp. supplementation as probiotics in cultured fish diets has a long history of safe and effective use. Specifically, B. velezensis show great promise in fine-tuning the European sea bass disease resistance against the pathogenicity caused by several members of the Vibrio family. However, the immunomodulatory mechanisms behind this response remain poorly understood. Here, to examine the inherent immune variations in sea bass, two equal groups were fed for 30 days with a steady diet, with one treatment supplemented with B. velezensis. The serum bactericidal capacity against live cells of Vibrio anguillarum strain 507 and the nitric oxide and lysozyme lytic activities were assayed. At the cellular level, the phagocytic response of peripheral blood leukocytes against inactivated Candida albicans was determined. Moreover, head-kidney (HK) total leukocytes were isolated from previously in vivo treated fish with LPS of V. anguillarum strain 507. Mechanistically, the expression of some essential proinflammatory genes (interleukin-1 (il1b), tumor necrosis factor-alpha (tnfa), and cyclooxygenase 2 (cox2) and the sea bass specific antimicrobial peptide (AMP) dicentracin (dic) expressions were assessed. Surprisingly, the probiotic supplementation significantly increased all humoral lytic and cellular activities assayed in the treated sea bass. In addition, time-dependent differences were observed between the control and probiotic treated groups for all the HK genes markers subjected to the sublethal LPS dose. Although the il1b was the fastest responding gene to a significant level at 48 h post-injection (hpi), all the other genes followed 72 h in the probiotic supplemented group. Finally, an in vivo bacteria challenge against live V. anguillarum was conducted. The probiotic fed fish observed a significantly higher survival. Overall, our results provide clear vertical evidence on the beneficial immune effects of B. velezensis and unveil some fundamental immune mechanisms behind its application as a probiotic agent in intensively cultured European sea bass.

Temporal Transcriptional Responses of a Vibrio alginolyticus Strain to Podoviridae Phage HH109 Revealed by RNA-Seq.

ABSTRACTPhage are thought to exhibit control over host genes during infection. As a preliminary investigation of the kinetics and magnitude of co-expression between phage and bacteria, we compared the global transcriptional profiles for Vibrio alginolyticus strain E110 and its lytic phage HH109 by using RNA sequencing. In total, 24.7% (1,143/4,620) of the host protein-coding genes were differentially expressed genes during infection (DEGs). Functional analysis of the host DEGs suggests that phage HH109 induced rapid and distinctive changes when compared with 60- and 120-min postinfection (mpi). Based on gene co-expression network analysis, an uncharacterized late gene gp27 encoded by the phage HH109 was predicted to modulate the host’s membrane transport and/or transcriptional regulation. Furthermore, expression of several bacterial virulence genes was downregulated while drug resistance genes were upregulated. This work contributes to an in-depth understanding of the reciprocal interactions of lytic phage HH109 and its pathogenic Vibrio host E110, and can provide new insights into the research and development of phage therapy against pathogenic Vibrio infections in the economically significant aquatic animals.IMPORTANCE Vibrio alginolyticus is a common opportunistic pathogen that causes mass mortality in cultured marine animals. Phage HH109 lyses pathogenic V. alginolyticus strain E110 with high efficiency and thus serves as a useful model to understand the dynamic interplay of a phage and its host. Global transcriptomic responses of strain E110 post-HH109 infection were characterized by using RNA sequencing, elucidating step-by-step control by HH109, an antiphage-like responses, and the elevated expression of drug resistance. This study provides a detailed molecular description phage and V. alginolyticus, providing insight into better prevention and control of vibriosis in aquatic animals.

Epidemiological and etiological characteristics of Vibrio parahaemolyticus strains causing foodborne disease outbreaks in Guangdong Province from 2017 to 2020

Objective: To study the epidemiological and pathogenic characteristics of Vibrio parahaemolyticus isolated from outbreaks cases in Guangdong Province, 2017-2020. Methods: Epidemiological characteristics of 87 outbreak events caused by Vibrio parahaemolyticus were analyzed. Strains were serotyped, and then analyzed by pulsed-field gel electrophoresis (PFGE). Results: The food-borne disease outbreak caused by Vibrio parahaemolyticus was found in 16 cities. 44.8% (39/87) and 37.9% (33/87) of the outbreaks occurred in hotels, restaurants and school canteens, respectively. Improper food processing and storage (40.2%, 35/87) and cross contamination caused by indiscriminate raw and cooked food (25.3%, 22/87) were the main causes of food-borne disease outbreaks of Vibrio parahaemolyticus. The main serotypes of patient derived strains were O3:K6 (87.5%) and O4:KUT (22.5%). The similarity value between O3:K6 type isolates was 65.5%-100.0%, and the PFGE pattern similarity value of O4:KUT type isolates was 66.5%-100.0%. Conclusion: Outbreaks caused by Vibrio parahaemolyticus are widely distributed in Guangdong province. It is necessary to strengthen the publicity and education on the correct handling of food in hotels, restaurants, schools, and unit canteens. O3:K6 and O4:KUT serotypes are the main serotypes of the outbreak. There is genetic diversity among the epidemic strains.

Identification, characterization and infection dynamics of Vibrio strains in phyllosoma of Thenus unimaculatus

ABSTRACT The present study investigates Vibrio outbreak in the hatchery system designed for larval rearing of shovel-nosed lobster Thenus unimaculatus in India. High larval mortalities during the episode led to an almost complete loss of the larval stock during the first 10 days. Microscopic examination revealed heavy fouling of the phyllosoma appendages. Histopathological analysis showed the presence of bacteria in larval tissues. Investigation by scanning electron microscopy revealed the formation of bacterial plaques on appendages and adhesion of bacteria on fine setae in heavily infected larvae. Bacteria isolated from larvae and identified by 16S rRNA sequencing and phylogenetic analysis indicated that the strains were closely related to luminescent Vibrio campbellii and Vibrio harveyi. The virulence potential of Vibrio strains isolated from larvae was evaluated through an experimental infection. The study helps to understand microbial infection and its impact on phyllosoma survival and may allow a more effective health management regime to improve larval survival in the hatchery phase.

Gut microbiota analysis of Blenniidae fishes including an algae-eating fish and clear boundary formation among isolated Vibrio strains

Some marine fishes are algae-feeding, and the microorganisms in their digestive tracts produce carbohydrate hydrolyzing enzymes such as agarose and fucosidase, which are potentially interesting resource for new functional enzymes. The purpose of this study was to establish a method for identifying and utilizing characteristic bacteria from the intestines of two algae-eating fish species: Andamia tetradactylus, which exclusively eats algae on the rock surface, and stellar rockskipper Entomacrodus stellifer, which feeds on both algae and invertebrates. We tested the species composition of the intestinal bacterial flora and found that Proteobacteria were commonly found both in species as in the common gut communities of marine fish, whereas Spirochaetes and Tenericutes occupied the flora of A. tetradactylus. We then performed anaerobic and aerobic cultures and isolated 34 and 44 strains including 48 strains belonged to Vibrio species from A. tetradactylus and E. stellifer. We observed that some Vibrio strains formed a clear boundary to avoid contacting other strains of bacteria. Whole-genome sequencing of such two Vibrio alginolyticus strains revealed two cyclic chromosomes commonly found in the genome of Vibrio species, and some unique genes encoding alginate lyase, chitinases, and type I-F CRISPR-associated endoribonuclease for the first time in Vibrio alginolyticus.

Expression of the AHPND Toxins PirAvp and PirBvp Is Regulated by Components of the Vibrio parahaemolyticus Quorum Sensing (QS) System.

Acute hepatopancreatic necrosis disease (AHPND) in shrimp is caused by Vibrio strains that harbor a pVA1-like plasmid containing the pirA and pirB genes. It is also known that the production of the PirA and PirB proteins, which are the key factors that drive the observed symptoms of AHPND, can be influenced by environmental conditions and that this leads to changes in the virulence of the bacteria. However, to our knowledge, the mechanisms involved in regulating the expression of the pirA/pirB genes have not previously been investigated. In this study, we show that in the AHPND-causing Vibrio parahaemolyticus 3HP strain, the pirAvp and pirBvp genes are highly expressed in the early log phase of the growth curve. Subsequently, the expression of the PirAvp and PirBvp proteins continues throughout the log phase. When we compared mutant strains with a deletion or substitution in two of the quorum sensing (QS) master regulators, luxO and/or opaR (luxOD47E, ΔopaR, ΔluxO, and ΔopaRΔluxO), our results suggested that expression of the pirAvp and pirBvp genes was related to the QS system, with luxO acting as a negative regulator of pirAvp and pirBvp without any mediation by opaRvp. In the promoter region of the pirAvp/pirBvp operon, we also identified a putative consensus binding site for the QS transcriptional regulator AphB. Real-time PCR further showed that aphBvp was negatively controlled by LuxOvp, and that its expression paralleled the expression patterns of pirAvp and pirBvp. An electrophoretic mobility shift assay (EMSA) showed that AphBvp could bind to this predicted region, even though another QS transcriptional regulator, AphAvp, could not. Taken together, these findings suggest that the QS system may regulate pirAvp/pirBvp expression through AphBvp.

Pathogenic potential of non-clinical Vibrio parahaemolyticus strains isolated from the aquatic environments in Southern India

Pathogenic potential of non-clinical Vibrio parahaemolyticus strains isolated from the aquatic environments in Southern India

Skin Culturable Microbiota in Farmed European Seabass (Dicentrarchuslabrax) in Two Aquacultures with and without Antibiotic Use

This study examined culturable skin microbiota that was associated with farmed European seabass (Dicentrarchus labrax). Healthy European seabass were sampled during summer commercial harvest from one conventional fish farm where antibiotics are used, and from another practicing a certified antibiotic-free fish aquaculture. Physicochemical and microbiological analysis of seawater and sediment were performed, as well as determination of culturable bacteria, including Vibrio, from skin swabs of European seabass and seawater and sediment at both farms. Samples were processed for isolation of bacteria and their characterization by molecular and antibiotic susceptibility tests. In both fish farms, most of the bacteria that were identified in the skin belonged to the genera Pseudomonas and Vibrio. Some of the microbiota that were identified are known to be pathogenic to fish: V.alginolyticus, V. anguillarum, and V. harveyi. Vibrio strains showed higher resistance to certain antibiotics compared to previous studies. This study provides, for the first time, information on the culturable skin bacteria that is associated with healthy European seabass under culture conditions with and without the use of antibiotics. This information will be useful in assessing how changes in culturable microbiota may affect the health of farmed European seabass, indicating a potential problem for fish health management during disease outbreaks.

Comparative genome analyses of five Vibrio penaeicida strains provide insights into their virulence-related factors.

Vibrio penaeicida (family Vibrionaceae ) is an important bacterial pathogen that affects Japanese shrimp aquaculture. Only two whole-genome sequences of V. penaeicida are publicly available, which has hampered our understanding of the pathogenesis of shrimp vibriosis caused by this bacterium. To gain insight into the genetic features, evolution and pathogenicity of V. penaeicida, we sequenced five V. penaeicida strains (IFO 15640T, IFO 15641, IFO 15642, TUMSAT-OK1 and TUMSAT-OK2) and performed comparative genomic analyses. Virulence factors and mobile genetic elements were detected. Furthermore, average nucleotide identities (ANIs), clusters of orthologous groups and phylogenetic relationships were evaluated. The V. penaeicida genome consists of two circular chromosomes. Chromosome I sizes ranged from 4.1 to 4.3 Mb, the GC content ranged from 43.9 to 44.1 %, and the number of predicted protein-coding sequences (CDSs) ranged from 3620 to 3782. Chromosome II sizes ranged from 2.2 to 2.4 Mb, the GC content ranged from 43.5 to 43.8 %, and the number of predicted CDSs ranged from 1992 to 2273. All strains except IFO 15641 harboured one plasmid, having sizes that ranged from 150 to 285 kb. All five genomes had typical virulence factors, including adherence, anti-phagocytosis, flagella-related proteins and toxins (repeats-in-toxin and thermolabile haemolysin). The genomes also contained factors responsible for iron uptake and the type II, IV and VI secretion systems. The genome of strain TUMSAT-OK2 tended to encode more prophage regions than the other strains, whereas the genome of strain IFO 15640T had the highest number of regions encoding genomic islands. For comparative genome analysis, we used V. penaeicida (strain CAIM 285T) as a reference strain. ANIs between strain CAIM 285T and the five V. penaeicida strains were >95 %, which indicated that these strains belong to the same species. Orthology cluster analysis showed that strains TUMSAT-OK1 and TUMSAT-OK2 had the greatest number of shared gene clusters, followed by strains CAIM 285T and IFO 15640T. These strains were also the most closely related to each other in a phylogenetic analysis. This study presents the first comparative genome analysis of V. penaeicida and these results will be useful for understanding the pathogenesis of this bacterium.

Enteric nervous system modulation of luminal pH modifies the microbial environment to promote intestinal health.

The enteric nervous system (ENS) controls many aspects of intestinal homeostasis, including parameters that shape the habitat of microbial residents. Previously we showed that zebrafish lacking an ENS, due to deficiency of the sox10 gene, develop intestinal inflammation and bacterial dysbiosis, with an expansion of proinflammatory Vibrio strains. To understand the primary defects resulting in dysbiosis in sox10 mutants, we investigated how the ENS shapes the intestinal environment in the absence of microbiota and associated inflammatory responses. We found that intestinal transit, intestinal permeability, and luminal pH regulation are all aberrant in sox10 mutants, independent of microbially induced inflammation. Treatment with the proton pump inhibitor, omeprazole, corrected the more acidic luminal pH of sox10 mutants to wild type levels. Omeprazole treatment also prevented overabundance of Vibrio and ameliorated inflammation in sox10 mutant intestines. Treatment with the carbonic anhydrase inhibitor, acetazolamide, caused wild type luminal pH to become more acidic, and increased both Vibrio abundance and intestinal inflammation. We conclude that a primary function of the ENS is to regulate luminal pH, which plays a critical role in shaping the resident microbial community and regulating intestinal inflammation.

Whole-Genome Sequences of Vibrio Species from Warm-Water Shrimps Imported into Canada: Detection of Genetic Elements Associated with Antimicrobial Resistance and Potential Mobilizing Capacities.

ABSTRACTWe present draft genome sequences of Vibrio species (Vibrio alginolyticus, Vibrio cholerae, and two Vibrio parahaemolyticus strains) that were isolated from warm-water shrimps imported into Canada. All four isolates harbor genetic elements associated with antimicrobial resistance (AMR), including mobile genetic elements that can promote horizontal transfer of AMR genes.

Effect of sunlight and salinity on the survival of pathogenic and non-pathogenic strains of Vibrio parahaemolyticus in water microcosms.

The effect of sunlight and salinities (10, 20, 39, and 60 psu) on the survival of Vibrio parahaemolyticus strains carrying either (thermostable direct hemolysin) tdh, the (thermostable related hemolysin) trh, and both or none of them were studied in water microcosms stabilized at 20°C using plate count agar and acridine orange direct viable count. All V.parahaemolyticus strains exposed to sunlight rapidly lose their culturability and evolve into a viable but non-culturable state (VBNC). However, the tdh positive strains remain more culturable than the non-virulent or trh positive strain but statically insignificant. At tested salinities, the survival time was higher at 10, 20, and 60 psu compared with that observed in seawater (39 psu). In seawater under dark condition, Vibrio strains remain culturable for up to 200 days with a significant difference between strains (p < 0.05). Furthermore, the non-pathogenic strain survives longer than the virulent ones. At different salinities, a better adaptation is observed at 10 and 20 psu compared with 39 and 60 psu. Resuscitations essays performed on VBNC bacteria in a nutrient broth at 20°C and 37°C does not show any revivification. PRACTITIONER POINTS: Effect of sunlight and salinities on the survival of V.parahaemolyticus in the marine environment. Resuscitation essay performed on viable but no cultivable bacteria. Microscope motility examines show that all strains exposed to sunlight remain motile after the loss of cultivability.

Polimeric Immunoglobulin Diagnosticum for Detection of Cholera Toxin and Assessing the Level of Its Production by Vibrios

A marker of the epidemic significance of Vibrio cholerae is their toxigenicity. Therefore, much attention is currently paid to the creation of diagnostic preparations for the detection of cholera toxin and assessment of the level of its production. The volumetric immunosuspension agglomeration reaction, carried out with the help of latex diagnosticums, is an analogue of the indirect hemagglutination reaction, an affordable and technically simple method, since it does not require special equipment and can be used when conducting research in the field. The aim of the study was to design a polymeric immunoglobulin diagnosticum for determining cholera toxin and the level of its production by vibrio strains. Materials and methods. Cholera toxin was obtained from the producer strain Vibrio cholerae Classical 569 B. Rabbit serum to the toxin was obtained according to the method selected by the authors. A polymeric diagnostic immunoglobulin antitoxic drug was obtained through sensitizing immunoglobulins from cholera antitoxic rabbit serum on the surface of polyacrolein microspheres with a size of (1±0.1) μm. Results and discussion. The analytical sensitivity of the developed diagnostic preparation with control cholera toxin is 100 ng/ml. It detects cholera toxin in toxigenic strains of Vibrio cholerae in a titer of 1:16 – 1:512, gives negative results with non-toxigenic strains of V. cholerae O1, V. Cholerae nonO1/nonO139, with samples of heterologous cultures, LPS preparations, liquid nutrient medium used for the cultivation of V. cholerae. Thus, a polymeric immunoglobulin diagnosticum has been constructed to detect and quantify the production of cholera toxin by vibrio strains, and its analytical sensitivity and specificity have been established.

Crassostrea Gigas Oysters from a Non-Intensive Farming Area Naturally Harbor Pathogenic Vibrio Strains

Crassostrea Gigas Oysters from a Non-Intensive Farming Area Naturally Harbor Pathogenic Vibrio Strains

Glycosaminoglycan-like sulfated polysaccharides from Vibrio diabolicus bacterium: Semi-synthesis and characterization

Sulfated glycosaminoglycan (GAG) analogues derived from plant, algae or microbial sourced polysaccharides are highly interesting in order to gain bioactivities similar to sulfated GAGs but without risks and concerns derived from their typical animal sources. Since the exopolysaccharide (EPS) produced by the bacterium Vibrio diabolicus HE800 strain from deep-sea hydrothermal vents is known to have a GAG-like structure with a linear backbone composed of unsulfated aminosugar and uronic acid monomers, its structural modification through four different semi-synthetic sulfation strategies has been performed. A detailed structural characterization of the six obtained polysaccharides revealed that three different sulfation patterns (per-O-sulfation, a single N-sulfation and a selective primary hydroxyls sulfation) were achieved, with molecular weights ranging from 5 to 40 kDa. A Surface Plasmonic Resonance (SPR) investigation of the affinity between such polysaccharides and a set of growth factors revealed that binding strength is primarily depending on polysaccharide sulfation degree.

CRISPR-Cas systems are present predominantly on chromosome and its relationship with MEGs in Vibrio species.

Bacteria have developed diverse strategies to counteract virus predation, one of which is the clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR associated (Cas) proteins immune defense system. In this study, the structure and function of the CRISPR-Cas system in 120 Vibrio strains were analyzed by bioinformatics methods, as well as the correlation between CRISPR and mobile genetic elements (MEGs). Only 61 Vibrio strains contained one or more CRISPR structures, and finally 102 CRISPRs were identified. The typical repeat size was 28bp, and the total length of CRISPRs is nearly 60bp, which was the most stable length of CRISPR in Vibrio strains. The types of CRISPR-Cas present in 61 strains were I-C, I-E, I-F, II-B, III-B, III-D and the rare type IV systems. Through principal component analysis, we found that Cas gene was most closely related to CRISPR. In addition, phages and plasmids were also highly correlated, showing negative correlation with CRISPR-Cas system. CRISPR-Cas predominantly present on chromosome within Vibrio while rarely in plasmids. Comparing the structural characteristics of plasmids containing CRISPR and without CRISPR, we found plasmid pMBL287 with CRISPR contained a bacteriophage f237, with more MGES, suggesting the diversity was greater. In addition, the same mobile genetic elements IS256 and ISL3 were found in the upstream and downstream of CRISPR. This study provides the prevalence, diversity and phylogenetic distribution of CRISPR-Cas in Vibrio, revealing which type of CRISPR-Cas system is predominant, and the factors affecting its function, as well as its relationship with mobile genetic elements.