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Proceedings of the National Academy of... Jul 2024The outer membrane (OM) of gram-negative bacteria serves as a vital organelle that is densely populated with OM proteins (OMPs) and plays pivotal roles in cellular...
The outer membrane (OM) of gram-negative bacteria serves as a vital organelle that is densely populated with OM proteins (OMPs) and plays pivotal roles in cellular functions and virulence. The assembly and insertion of these OMPs into the OM represent a fundamental process requiring specialized molecular chaperones. One example is the translocation and assembly module (TAM), which functions as a transenvelope chaperone promoting the folding of specific autotransporters, adhesins, and secretion systems. The catalytic unit of TAM, TamA, comprises a catalytic β-barrel domain anchored within the OM and three periplasmic polypeptide-transport-associated (POTRA) domains that recruit the TamB subunit. The latter acts as a periplasmic ladder that facilitates the transport of unfolded OMPs across the periplasm. In addition to their role in recruiting the auxiliary protein TamB, our data demonstrate that the POTRA domains mediate interactions with the inner surface of the OM, ultimately modulating the membrane properties. Through the integration of X-ray crystallography, molecular dynamic simulations, and biomolecular interaction methodologies, we located the membrane-binding site on the first and second POTRA domains. Our data highlight a binding preference for phosphatidylglycerol, a minor lipid constituent present in the OM, which has been previously reported to facilitate OMP assembly. In the context of the densely OMP-populated membrane, this association may serve as a mechanism to secure lipid accessibility for nascent OMPs through steric interactions with existing OMPs, in addition to creating favorable conditions for OMP biogenesis.
Topics: Bacterial Outer Membrane Proteins; Escherichia coli Proteins; Protein Domains; Bacterial Outer Membrane; Escherichia coli; Molecular Chaperones; Protein Folding; Periplasm; Models, Molecular
PubMed: 38959031
DOI: 10.1073/pnas.2402543121 -
Database : the Journal of Biological... Jul 2024Myxobacteria are predatory bacteria with antimicrobial activity, utilizing complex mechanisms to kill their prey and assimilate their macromolecules. Having large...
Myxobacteria are predatory bacteria with antimicrobial activity, utilizing complex mechanisms to kill their prey and assimilate their macromolecules. Having large genomes encoding hundreds of secondary metabolites, hydrolytic enzymes and antimicrobial peptides, these organisms are widely studied for their antibiotic potential. MyxoPortal is a comprehensive genomic database hosting 262 genomes of myxobacterial strains. Datasets included provide genome annotations with gene locations, functions, amino acids and nucleotide sequences, allowing analysis of evolutionary and taxonomical relationships between strains and genes. Biosynthetic gene clusters are identified by AntiSMASH, and dbAMP-generated antimicrobial peptide sequences are included as a resource for novel antimicrobial discoveries, while curated datasets of CRISPR/Cas genes, regulatory protein sequences, and phage associated genes give useful insights into each strain's biological properties. MyxoPortal is an intuitive open-source database that brings together application-oriented genomic features that can be used in taxonomy, evolution, predation and antimicrobial research. MyxoPortal can be accessed at http://dicsoft1.physics.iisc.ac.in/MyxoPortal/. Database URL: http://dicsoft1.physics.iisc.ac.in/MyxoPortal/. Graphical Abstract.
Topics: Myxococcales; Genome, Bacterial; Databases, Genetic; Genomics
PubMed: 38958433
DOI: 10.1093/database/baae056 -
Revista Brasileira de Parasitologia... 2024The Amblyomma genus (Arachnida: Ixodidae) is widely distributed in South America, with 34 species occurring in Brazil. Amblyomma nodosum Neumann 1889 is a species that...
The Amblyomma genus (Arachnida: Ixodidae) is widely distributed in South America, with 34 species occurring in Brazil. Amblyomma nodosum Neumann 1889 is a species that predominantly feeds on Passeriformes during immature stages (larvae and nymphs) and anteaters (Myrmecophagidae) during adult stages. The aim of the present study is to report, for the first time, an unusual case of parasitism by adults of A. nodosum on a yellow cururu toad (Rhinella icterica) captured in the city of Nossa Senhora da Glória, Sergipe state (Northeastern Brazil) in the Caatinga biome, and also investigate the presence of DNA of Rickettsia in the collected material. DNA was extracted from all specimens collected (N=8) and subjected to PCR assays based on the tick 16S rRNA endogenous gene and gltA gene for Rickettsia sp. All samples (8/8; 100%) were positive for the 16S rRNA endogenous gene and two amplicons (obtained from one male and one female) were purified and sequenced. The BLASTn analysis of the sequences revealed a high degree of similarity (95-100%) with A. nodosum sequences previously deposited on GenBank, while the phylogenetic analysis clustered the sequences obtained in the same clade as A. nodosum sequences from Brazil.
Topics: Animals; Brazil; Amblyomma; Tick Infestations; Male; Female; Rickettsia; Bufonidae
PubMed: 38958294
DOI: 10.1590/S1984-29612024031 -
Ghana Medical Journal Mar 2024The study aimed to detect the presence of infection in children using two investigative methods: the rapid urease test and histological methods. It also examined the...
OBJECTIVE
The study aimed to detect the presence of infection in children using two investigative methods: the rapid urease test and histological methods. It also examined the relationship between socioeconomic status and Helicobacter pylori infection.
DESIGN
This was a cross-sectional study conducted in the paediatric theatre at Korle Bu Teaching Hospital in Accra, Ghana.
PARTICIPANTS
Children who were scheduled for upper gastrointestinal endoscopy were recruited into the study.
MAIN OUTCOME MEASURES
The presence of Helicobacter pylori in gastric biopsies was measured using a rapid urease test and histology.
RESULTS
Seventy-three children aged 2 years to 16 years were seen during the period. Both tests were positive at the same time in 36 (49.3%) out of the 73 children (p<0.0001). The positivity rates for the rapid urease test and histology were 57.5% and 53.4 %, respectively. Significant predictors of the histology presence of H. pylori were a large household size of at least 6 members (AOR: 4.03; p<0.013) and the presence of pets at home (AOR: 3.23; p<0.044).
CONCLUSIONS
Substantial agreement was found between the rapid urease test and histology examination of gastric biopsies for the presence of . Children from large households and those with pets at home appear to have increased odds of having infection of the gastric mucosa.
FUNDING
None declared.
Topics: Humans; Helicobacter Infections; Helicobacter pylori; Child; Cross-Sectional Studies; Male; Urease; Female; Child, Preschool; Adolescent; Ghana; Biopsy; Socioeconomic Factors; Gastric Mucosa
PubMed: 38957277
DOI: 10.4314/gmj.v58i1.10 -
Ghana Medical Journal Mar 2024This study aims to examine the frequency of Paratyphi found in blood cultures and evaluate the antibiotic susceptibility pattern of isolates to different antibiotics....
OBJECTIVE
This study aims to examine the frequency of Paratyphi found in blood cultures and evaluate the antibiotic susceptibility pattern of isolates to different antibiotics. Additionally, the study aims to assess the paradigm shift in the trend of enteric fever caused by Typhi (. Typhi) to Paratyphi(. Paratyphi) .
STUDY DESIGN
Retrospective study.
PARTICIPANT
The study enrolled patients aged 12 years and above diagnosed with enteric fever (positive blood culture) and admitted to Peelamedu Samanaidu Govindasamy Naidu (PSG) Hospital.
INTERVENTIONS
The study analyzed demographic and antibiotic susceptibility profiles of isolates collected from 106 enteric fever patients in the hospital between 2010 and 2022. The susceptibility profiles of isolates to multiple antibiotics were assessed.
RESULTS
There were 106 participants, and 95 (89.62%) of them had enteric fever linked to Typhi, while only 11 (10.38%) had enteric fever linked to Paratyphi A. From 2010 to 2022, the study discovered a general decline in the prevalence of enteric fever caused by species. But between 2014 and 2022, the incidence of enteric fever linked to rapidly increased. Azithromycin (100% , n = 106) and ceftriaxone (99% , n = 105) were highly effective against the isolates, whereas nalidixic acid was resisted by 3 isolates (4.72%, n = 3).
CONCLUSION
The study observed a higher incidence of Typhi in comparison to Paratyphi A and a greater susceptibility of males to enteric fever.
FUNDING
None declared.
Topics: Humans; Male; Female; Anti-Bacterial Agents; Typhoid Fever; Retrospective Studies; Salmonella typhi; Microbial Sensitivity Tests; Salmonella paratyphi A; Adult; Adolescent; Child; Middle Aged; Young Adult; Paratyphoid Fever; Incidence; Drug Resistance, Bacterial; Azithromycin; Ceftriaxone; Aged; Prevalence
PubMed: 38957275
DOI: 10.4314/gmj.v58i1.12 -
Journal of the American Chemical Society Jul 2024Various species cause well-known plant diseases. Among various pathogenic factors, the role of α-1,6-cyclized β-1,2-glucohexadecaose (CβG16α) produced by pv. was...
Various species cause well-known plant diseases. Among various pathogenic factors, the role of α-1,6-cyclized β-1,2-glucohexadecaose (CβG16α) produced by pv. was previously shown to be vital for infecting model organisms, and . However, enzymes responsible for biosynthesizing CβG16α are essentially unknown, which limits the generation of agrichemicals that inhibit CβG16α synthesis. In this study, we discovered that OpgD from pv. converts linear β-1,2-glucan to CβG16α. Structural and functional analyses revealed OpgD from pv. possesses an anomer-inverting transglycosylation mechanism, which is unprecedented among glycoside hydrolase family enzymes.
Topics: Xanthomonas campestris; Xanthomonas; Plant Diseases; Oligosaccharides; Models, Molecular
PubMed: 38957137
DOI: 10.1021/jacs.4c02579 -
Journal of Agricultural and Food... Jul 2024Plants withstand pathogen attacks by recruiting beneficial bacteria to the rhizosphere and passing their legacy on to the next generation. However, the underlying...
Plants withstand pathogen attacks by recruiting beneficial bacteria to the rhizosphere and passing their legacy on to the next generation. However, the underlying mechanisms involved in this process remain unclear. In our study, we combined microbiomic and transcriptomic analyses to reveal how the rhizosphere microbiome assembled through multiple generations and defense-related genes expressed in under pathogen attack stress. Our results showed that continuous exposure to the pathogen DC3000 led to improved growth and increased disease resistance in a third generation of mutant . It could be attributed to the enrichment of specific rhizosphere bacteria, such as and . Pathways associated with plant immunity and growth in . , such as MAPK signaling pathways, phytohormone signal transduction, ABC transporter proteins, and flavonoid biosynthesis, were activated under the influence of rhizosphere bacterial communities. Our findings provide a scientific basis for explaining the relationship between beneficial microbes and defense-related gene expression. Understanding microbial communities and the mechanisms involved in plant responses to disease can contribute to better plant management and reduction of pesticide use.
Topics: Arabidopsis; Rhizosphere; Plant Diseases; Pseudomonas syringae; Disease Resistance; Microbiota; Bacteria; Soil Microbiology; Arabidopsis Proteins; Adaptation, Physiological; Plant Roots; Gene Expression Regulation, Plant
PubMed: 38957087
DOI: 10.1021/acs.jafc.4c02200 -
Journal of Agricultural and Food... Jul 2024Nanobodies (Nbs) serve as powerful tools in immunoassays. However, their small size and monovalent properties pose challenges for practical application. Multimerization...
Nanobodies (Nbs) serve as powerful tools in immunoassays. However, their small size and monovalent properties pose challenges for practical application. Multimerization emerges as a significant strategy to address these limitations, enhancing the utilization of nanobodies in immunoassays. Herein, we report the construction of a -specific fenobody (Fb) through the fusion of a nanobody to ferritin, resulting in a self-assembled 24-valent nanocage-like structure. The fenobody exhibits a 35-fold increase in avidity compared to the conventional nanobody while retaining good thermostability and specificity. Leveraging this advancement, three ELISA modes were designed using Fb as the capture antibody, along with unmodified Nb422 (FbNb-ELISA), biotinylated Nb422 (FbBio-ELISA), and phage-displayed Nb422 (FbP-ELISA) as the detection antibody, respectively. Notably, the FbNb-ELISA demonstrates a detection limit (LOD) of 3.56 × 10 CFU/mL, which is 16-fold lower than that of FbBio-ELISA and similar to FbP-ELISA. Moreover, a fenobody and nanobody sandwich chemiluminescent enzyme immunoassay (FbNb-CLISA) was developed by replacing the TMB chromogenic substrate with luminal, resulting in a 12-fold reduction in the LOD. Overall, the ferritin-displayed technology represents a promising methodology for enhancing the detection performance of nanobody-based sandwich ELISAs, thereby expanding the applicability of Nbs in food detection and other fields requiring multivalent modification.
Topics: Ferritins; Single-Domain Antibodies; Salmonella; Enzyme-Linked Immunosorbent Assay; Limit of Detection; Antibody Affinity; Antibodies, Bacterial; Immunoassay
PubMed: 38957086
DOI: 10.1021/acs.jafc.4c03606 -
Rural and Remote Health Jun 2024An outbreak of gastroenteritis due to Salmonella Give, a very rarely identified serotype in human isolates in Greece, occurred in participants of a religious festival in...
INTRODUCTION
An outbreak of gastroenteritis due to Salmonella Give, a very rarely identified serotype in human isolates in Greece, occurred in participants of a religious festival in a rural area of southern Greece, in September 2022. The objectives of this study were to describe the outbreak in terms of epidemiology, identify the vehicle of transmission of the foodborne pathogen and recommend prevention measures.
METHODS
The outbreak was linked to the consumption of a local traditional recipe of roasted pork meat served by a street food vendor. In 2018, the same food item, served in a restaurant in the same region, was implicated in another S. Give outbreak.
RESULTS
Outbreak investigations revealed that outbreak-associated isolates, of food and human origin, belonged to the same S. Give strain. Significant deficiencies regarding food safety practices were identified.
CONCLUSION
Technical knowledge about pathogen transmission paths is important in order for both food handlers and consumers to follow hygiene and sanitary measures, mainly in cases of mass gatherings, where large quantities of food are prepared, handled, cooked and served. Efficient official supervision, mainly during summer festivals, is required in order to avoid recurrence of foodborne infections by different combinations of pathogens/food commodities.
Topics: Humans; Greece; Disease Outbreaks; Pork Meat; Male; Salmonella Food Poisoning; Female; Adult; Animals; Salmonella; Middle Aged; Gastroenteritis; Swine; Food Microbiology
PubMed: 38957085
DOI: 10.22605/RRH8391 -
BMC Research Notes Jul 2024Bartonella are emerging bacterial zoonotic pathogens. Utilization of clotted blood samples for surveillance of these bacteria in wildlife has begun to supersede the use...
OBJECTIVE
Bartonella are emerging bacterial zoonotic pathogens. Utilization of clotted blood samples for surveillance of these bacteria in wildlife has begun to supersede the use of tissues; however, the efficacy of these samples has not been fully investigated. Our objective was to compare the efficacy of spleen and blood samples for DNA extraction and direct detection of Bartonella spp. via qPCR. In addition, we present a protocol for improved DNA extraction from clotted, pelleted (i.e., centrifuged) blood samples obtained from wild small mammals.
RESULTS
DNA concentrations from kit-extracted blood clot samples were low and A260/A280 absorbance ratios indicated high impurity. Kit-based DNA extraction of spleen samples was efficient and produced ample DNA concentrations of good quality. We developed an in-house extraction method for the blood clots which resulted in apposite DNA quality when compared to spleen samples extracted via MagMAX DNA Ultra 2.0 kit. We detected Bartonella in 9/30 (30.0%) kit-extracted spleen DNA samples and 11/30 (36.7%) in-house-extracted blood clot samples using PCR. Our results suggest that kit-based methods may be less suitable for DNA extraction from blood clots, and that blood clot samples may be superior to tissues for Bartonella detection.
Topics: Animals; Bartonella; DNA, Bacterial; Spleen; Bartonella Infections; Animals, Wild; Real-Time Polymerase Chain Reaction
PubMed: 38956715
DOI: 10.1186/s13104-024-06841-5