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Yakugaku Zasshi : Journal of the... 2024Iron is necessary for all living organisms, and bacteria that cause infections in human hosts also need ferrous ions for their growth and proliferation. In the human... (Review)
Review
Iron is necessary for all living organisms, and bacteria that cause infections in human hosts also need ferrous ions for their growth and proliferation. In the human body, most ferric ions (Fe) are tightly bound to iron-binding proteins such as hemoglobin, transferrin, lactoferrin, and ferritin. Pathogenic bacteria express highly specific iron uptake systems, including siderophores and specific receptors. Most bacteria secrete siderophores, which are low-molecular weight metal-chelating agents, to capture Fe outside cell. Siderophores are mainly classified as either catecholate or hydroxamate. Vibrio vulnificus, a Gram-negative pathogenic bacterium, is responsible for serious infections in humans and requires iron for growth. A clinical isolate, V. vulnificus M2799, secretes a catecholate siderophore, vulnibactin, that captures ferric ions from the environment. In our study, we generated deletion mutants of the genes encoding proteins involved in the vulnibactin mediated iron-utilization system, such as ferric-vulnibactin receptor protein (VuuA), periplasmic ferric-vulnibactin binding protein (FatB), ferric-vulnibactin reductase (VuuB), and isochorismate synthase (ICS). ICS and VuuA are required under low-iron conditions for ferric-utilization in M2799, but the alternative proteins FatB and VuuB can function as a periplasmic binding protein and a ferric-chelate reductase, respectively. VatD, which functions as ferric-hydroxamate siderophores periplasmic binding protein, was shown to participate in the ferric-vulnibactin uptake system in the absence of FatB. Furthermore, the ferric-hydroxamate siderophore reductase IutB was observed to participate in ferric-vulnibactin reduction in the absence of VuuB. We propose that ferric-siderophore periplasmic binding proteins and ferric-chelate reductases represent potential targets for drug discovery in the context of infectious diseases.
Topics: Iron; Siderophores; Humans; Drug Discovery; Bacterial Infections; Molecular Targeted Therapy; Hydroxamic Acids; Iron-Binding Proteins
PubMed: 38825472
DOI: 10.1248/yakushi.23-00197-2 -
Molecular Biology Reports Jun 2024Cystatin is a protease inhibitor that also regulates genes expression linked to inflammation and plays a role in defense and regulation.
BACKGROUND
Cystatin is a protease inhibitor that also regulates genes expression linked to inflammation and plays a role in defense and regulation.
METHODS AND RESULTS
Cystatin 10 (Smcys10) was cloned from Scophthalmus maximus and encodes a 145 amino acid polypeptide. The results of qRT-PCR showed that Smcys10 exhibited tissue-specific expression patterns, and its expression was significantly higher in the skin than in other tissues. The expression level of Smcys10 was significantly different in the skin, gill, head kidney, spleen and macrophages after Vibrio anguillarum infection, indicating that Smcys10 may play an important role in resistance to V. anguillarum infection. The recombinant Smcys10 protein showed binding and agglutinating activity in a Ca-dependent manner against bacteria. rSmcys10 treatment upregulated the expression of IL-10, TNF-α and TGF-β in macrophages of turbot and hindered the release of lactate dehydrogenase (LDH) from macrophages after V. anguillarum infection, which confirmed that rSmcys10 reduced the damage to macrophages by V. anguillarum. The NF-κB pathway was suppressed by Smcys10, as demonstrated by dual-luciferase analysis.
CONCLUSIONS
These results indicated that Smcys10 is involved in the host antibacterial immune response.
Topics: Animals; Flatfishes; Vibrio; Cystatins; Fish Proteins; Macrophages; Fish Diseases; Vibrio Infections; NF-kappa B; Cloning, Molecular; Gene Expression Regulation
PubMed: 38824265
DOI: 10.1007/s11033-024-09634-y -
Nature Communications Jun 2024Vaccines and clean water shortages continue to give rise to cholera outbreaks in Africa. Coordinated efforts to increase vaccine distribution and improve physical...
Vaccines and clean water shortages continue to give rise to cholera outbreaks in Africa. Coordinated efforts to increase vaccine distribution and improve physical infrastructure are needed while considering future outbreaks and water demands due to conflicts and climate events.
Topics: Cholera; Humans; Africa; Cholera Vaccines; Disease Outbreaks
PubMed: 38824141
DOI: 10.1038/s41467-024-49077-4 -
Journal of Bacteriology Jun 2024Iron acquisition systems are crucial for pathogen growth and survival in iron-limiting host environments. To overcome nutritional immunity, bacterial pathogens evolved...
UNLABELLED
Iron acquisition systems are crucial for pathogen growth and survival in iron-limiting host environments. To overcome nutritional immunity, bacterial pathogens evolved to use diverse mechanisms to acquire iron. Here, we examine a heme acquisition system that utilizes hemophores called hemophilins which are also referred to as HphAs in several Gram-negative bacteria. In this study, we report three new HphA structures from , , and . Structural determination of HphAs revealed an N-terminal clamp-like domain that binds heme and a C-terminal eight-stranded β-barrel domain that shares the same architecture as the Slam-dependent Neisserial surface lipoproteins. The genetic organization of HphAs consists of genes encoding a Slam homolog and a TonB-dependent receptor (TBDR). We investigated the Slam-HphA system in the native organism or the reconstituted system in cells and found that the efficient secretion of HphA depends on Slam. The TBDR also played an important role in heme uptake and conferred specificity for its cognate HphA. Furthermore, bioinformatic analysis of HphA homologs revealed that HphAs are conserved in the alpha, beta, and gammaproteobacteria. Together, these results show that the Slam-dependent HphA-type hemophores are prevalent in Gram-negative bacteria and further expand the role of Slams in transporting soluble proteins.
IMPORTANCE
This paper describes the structure and function of a family of Slam (Type IX secretion System) secreted hemophores that bacteria use to uptake heme (iron) while establishing an infection. Using structure-based bioinformatics analysis to define the diversity and prevalence of this heme acquisition pathway, we discovered that a large portion of gammaproteobacterial harbors this system. As organisms, including , utilize this system to facilitate survival during host invasion, the identification of this heme acquisition system in bacteria species is valuable information and may represent a target for antimicrobials.
Topics: Gram-Negative Bacteria; Heme; Bacterial Proteins; Iron
PubMed: 38814789
DOI: 10.1128/jb.00027-24 -
Journal of Invertebrate Pathology Jul 2024Infectious myonecrosis virus (IMNV) has affected shrimp farming in many countries, such as northeastern Brazil and southeast Asia, and poses a serious threat to the...
Infectious myonecrosis virus (IMNV) has affected shrimp farming in many countries, such as northeastern Brazil and southeast Asia, and poses a serious threat to the global shrimp industry. Reverse transcription enzymatic recombinant amplification technology (RT-ERA) is a rapid DNA amplification assay with high specificity in isothermal conditions and has been widely applied to the pathogen's detection. In this study, two novel ERA assays of IMNV, real-time RT-ERA and an RT-ERA combined with lateral flow dipsticks assay (RT-ERA-LFD), were developed and evaluated. The real-time RT-ERA assay could be carried out at 38-42 °C and had the highest end-point fluorescence value and the smallest Ct value at 41 °C. The brightness and width of the detection line were at a maximum at 39 °C and 30 min, and these conditions were selected in RT-ERA-LFD. Both real-time RT-ERA and RT-ERA-LFD produced positive results with IMNV standard plasmids only and showed no cross-reaction with Vibrio parahaemolyticus, which causes acute hepatopancreatic necrosis disease (VpAHPND); white spot syndrome virus (WSSV); infectious hypodermal and hematopoietic necrosis virus (IHHNV); or Ecytonucleospora hepatopenaei (EHP). Meanwhile, we compared the sensitivities of nested RT-PCR, real-time RT-PCR, real-time RT-ERA, and RT-ERA-LFD. The sensitivities of real-time RT-ERA and RT-ERA-LFD were both 10 copies/μL. The detection sensitivities of nested RT-PCR and real-time RT-PCR were 10 and 10 copies/μL, respectively. As a result, two ERA assays were determined to be specific, sensitive, and economical methods for the on-site diagnosis of IMNV infection, showing great potential for the control of IMNV infections.
Topics: Animals; Nucleic Acid Amplification Techniques; Penaeidae; Recombinases; Sensitivity and Specificity
PubMed: 38810834
DOI: 10.1016/j.jip.2024.108143 -
Fish & Shellfish Immunology May 2024Interleukin-10 (IL-10) is an immunosuppressive cytokine, which plays a vital role in regulating inflammation for inhibiting the generation and function of...
Interleukin-10 (IL-10) is an immunosuppressive cytokine, which plays a vital role in regulating inflammation for inhibiting the generation and function of pro-inflammatory cytokines in vivo or in vitro. In the present study, the full length cDNA of IL-10 was characterized from Nibea albiflora (named as NaIL-10) of 1238 base pairs (bp), containing a 5'-UTR (untranslated region) of 350 bp, a 3'-UTR of 333 bp and an open reading frame (ORF) of 555 bp (Fig. 1A) to encode 184 amino acid residues with a signal peptide at the N-terminus. The sequence analysis showed that NaIL-10 possessed the typical IL-10 family symbolic motif and conversed cysteine residues, similar to its teleost orthologues. Real-time PCR indicated that NaIL-10 had wide distribution in different healthy tissues, with a relatively high expression in immune-related tissues (head kidney, spleen, kidney, liver and gill). Significantly, up-regulations of NaIL-10 after infection against Vibrio parahaemolyticus, Vibrio alginolyticus and Poly I:C were also observed. Subcellular localization manifested that NaIL-10 mainly distributed in the cytoplasm unevenly and aggregately, and there was also a small amount on the cell membrane, indicating that NaIL-10 was secreted to the extracellular space as the known IL-10 homologous molecules. It could co-locate with IL-10 Rα on the membrane of HEK293T cells for their potential interaction, and GST pull-down and Co-IP studies certified the specific and direct interaction between NaIL-10 and NaIL-10 Rα, confirming that an IL-10 ligand-receptor system existed in N.albiflora. The expression of pro-inflammatory cytokines, including TNF-α, IL-6, IL-1β, were dramatically inhibited in LPS-stimulated RAW264.7 macrophages pre-incubated with recombinant NaIL-10 protein, demonstrating its anti-inflammatory roles. Taken together, the results demonstrated the existence of IL-10 ligand-receptor system in N.albiflora for the first time, and indicated the suppressive function of NaIL-10 on pro-inflammatory cytokine expression in inflammatory response, which would be conducive to better comprehending the role of IL-10 in the immunomodulatory mechanisms of teleost.
PubMed: 38810711
DOI: 10.1016/j.fsi.2024.109654 -
Applied and Environmental Microbiology Jun 2024Antibiotics are often used to treat severe infections, with third-generation cephalosporins and tetracyclines combined or fluoroquinolones alone being recommended by...
Antibiotics are often used to treat severe infections, with third-generation cephalosporins and tetracyclines combined or fluoroquinolones alone being recommended by the US Centers for Disease Control and Prevention. Increases in antibiotic resistance of both environmental and clinical vibrios are of concern; however, limited longitudinal data have been generated among environmental isolates to inform how resistance patterns may be changing over time. Hence, we evaluated long-term trends in antibiotic resistance of vibrios isolated from Chesapeake Bay waters (Maryland) across two 3-year sampling periods (2009-2012 and 2019-2022). ( = 134) and ( = 94) tR-confirmed isolates were randomly selected from both sampling periods and tested for antimicrobial susceptibility against eight antibiotics using the Kirby-Bauer disk diffusion method. A high percentage (94%-96%) of isolates from both sampling periods were resistant to ampicillin and only 2%-6% of these isolates expressed intermediate resistance or resistance to third-generation cephalosporins, amikacin, tetracycline, and trimethoprim-sulfamethoxazole. Even lower percentages of resistant isolates were observed and those were mostly recovered from 2009 to 2012, however, the presence of multiple virulence factors was observed. The frequency of multi-drug resistance was relatively low (6%-8%) but included resistance against antibiotics used to treat severe vibriosis in adults and children. All isolates were susceptible to ciprofloxacin, a fluoroquinolone, indicating its sustained efficacy as a first-line agent in the treatment of severe vibriosis. Overall, our data indicate that antibiotic resistance patterns among and recovered from the lower Chesapeake Bay have remained relatively stable since 2009.IMPORTANCE spp. have historically been susceptible to most clinically relevant antibiotics; however, resistance and intermediate-resistance have been increasingly recorded in both environmental and clinical isolates. Our data showed that while the percentage of multi-drug resistance and resistance to antibiotics was relatively low and stable across time, some isolates displayed resistance and intermediate resistance to antibiotics typically used to treat severe vibriosis (e.g., third-generation cephalosporins, tetracyclines, sulfamethoxazole-trimethoprim, and aminoglycosides). Also, given the high case fatality rates observed with infections, the presence of multiple virulence factors in the tested isolates is concerning. Nevertheless, the continued susceptibility of all tested isolates against ciprofloxacin, a fluoroquinolone, is indicative of its use as an effective first-line treatment of severe spp. infections stemming from exposure to Chesapeake Bay waters or contaminated seafood ingestion.
Topics: Vibrio parahaemolyticus; Vibrio vulnificus; Bays; Anti-Bacterial Agents; Longitudinal Studies; Maryland; Microbial Sensitivity Tests; Drug Resistance, Bacterial; Vibrio Infections; Humans
PubMed: 38809043
DOI: 10.1128/aem.00539-24 -
The American Journal of Tropical... Jul 2024Information on notifiable bacterial diseases (NBD) in low- and middle-income countries (LMICs) is frequently incomplete. We developed the AutoMated tool for the...
Information on notifiable bacterial diseases (NBD) in low- and middle-income countries (LMICs) is frequently incomplete. We developed the AutoMated tool for the Antimicrobial resistance Surveillance System plus (AMASSplus), which can support hospitals to analyze their microbiology and hospital data files automatically (in CSV or Excel format) and promptly generate antimicrobial resistance surveillance and NBD reports (in PDF and CSV formats). The NBD reports included the total number of cases and deaths after Brucella spp., Burkholderia pseudomallei, Corynebacterium diphtheriae, Neisseria gonorrhoeae, Neisseria meningitidis, nontyphoidal Salmonella spp., Salmonella enterica serovar Paratyphi, Salmonella enterica serovar Typhi, Shigella spp., Streptococcus suis, and Vibrio spp. infections. We tested the tool in six hospitals in Thailand in 2022. The total number of deaths identified by the AMASSplus was higher than those reported to the national notifiable disease surveillance system (NNDSS); particularly for B. pseudomallei infection (134 versus 2 deaths). This tool could support the NNDSS in LMICs.
Topics: Thailand; Humans; Bacterial Infections; Hospitals; Disease Notification; Anti-Bacterial Agents; Drug Resistance, Bacterial; Population Surveillance
PubMed: 38806021
DOI: 10.4269/ajtmh.23-0848 -
Food Chemistry Oct 2024Vibrio vulnificus infection caused by contaminated aquatic products and seawater can lead to severe disease and high mortality. The development of a rapid and sensitive...
Vibrio vulnificus infection caused by contaminated aquatic products and seawater can lead to severe disease and high mortality. The development of a rapid and sensitive detection method for Vibrio vulnificus is vital to effectively prevent infection in advance. In this study, CeO@PtRu with high peroxidase activity was used to construct a colorimetric immunoassay for Vibrio vulnificus detection by conjugating polyclonal antibodies via the biotin-streptavidin system. The developed colorimetric biosensor for Vibrio vulnificus demonstrated rapid operability and good sensitivity with a detection range from 10 CFU/mL to 10 CFU/mL, and the limit of detection (LOD) is 193 CFU/mL. Moreover, the colorimetric biosensor showed excellent specificity and good recoveries from 98.70% to 102.10% with RSD < 7.45% for spiked real samples. This novel CeO@PtRu-based colorimetric biosensor has great application potential for the sensitive detection of Vibrio vulnificus in seafood.
Topics: Vibrio vulnificus; Colorimetry; Biosensing Techniques; Seafood; Cerium; Peroxidase; Limit of Detection; Food Contamination; Animals
PubMed: 38805924
DOI: 10.1016/j.foodchem.2024.139757 -
Animal Nutrition (Zhongguo Xu Mu Shou... Jun 2024This study was conducted to evaluate the effects of M-32 fermented soybean meal (MFSM) on growth, immunity, intestinal morphology, intestinal microbiota, and intestinal...
M-32 fermented soybean meal improves the growth, immunity parameters, intestinal morphology, disease resistance, intestinal microbiota and metabolome in Pacific white shrimp ().
This study was conducted to evaluate the effects of M-32 fermented soybean meal (MFSM) on growth, immunity, intestinal morphology, intestinal microbiota, and intestinal metabolome of Pacific white shrimp (). Four groups of diets were formulated, including control group (30% fish meal and 30% soybean meal [SBM] included in the basal diet) and three experimental groups which MFSM replaced 20% (MFSM20), 40% (MFSM40), and 60% (MFSM60) of SBM in control group, respectively. Results showed that the soluble proteins larger than 49 kDa in MFSM were almost completely degraded. Meanwhile, the crude protein, acid-soluble protein, and amino acid in MFSM were increased. The results of shrimp culture experiment showed that the replacement of SBM with MFSM decreased FCR ( < 0.001) and content of malondialdehyde ( = 0.007) in the experimental groups, and increased weight gain rate ( = 0.006), specific growth rate ( = 0.002), survival rate ( = 0.005), intestinal villus height ( < 0.001), myenteric thickness ( = 0.002), the activities of superoxide dismutase ( = 0.002), and lysozyme ( = 0.006) in experimental groups, as well as increased content of calcium (Ca) and phosphorus () in blood and muscle, and enhanced resistance to infection. The gut microbiota of MFSM groups was significantly different from that of the control group, and the abundance of Actinobacteria and Verrucomicrobia increased significantly in the MFSM60 group, whereas Proteobacteria and Firmicutes decreased. Compared with the control group, there were significant changes in the levels of several intestinal metabolites in the MFSM60 group, including leukotriene C5, prostaglandin A1, taurochenodeoxycholic acid, carnosine, and itaconic acid. The fermentation of SBM by the strain M-32 has the potential to enhance the nutritional quality of SBM, promote the growth of , boost immune response, improve intestinal morphology and microbiota composition, as well as influence intestinal metabolites.
PubMed: 38800738
DOI: 10.1016/j.aninu.2024.03.009