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Antonie Van Leeuwenhoek Jul 2024The Aeolian archipelago is known worldwide for its volcanic activity and hydrothermal emissions, of mainly carbon dioxide and hydrogen sulfide. Hydrogen, methane, and...
The Aeolian archipelago is known worldwide for its volcanic activity and hydrothermal emissions, of mainly carbon dioxide and hydrogen sulfide. Hydrogen, methane, and carbon monoxide are minor components of these emissions which together can feed large quantities of bacteria and archaea that do contribute to the removal of these notorious greenhouse gases. Here we analyzed the metagenome of samples taken from the Levante bay on Vulcano Island, Italy. Using a gene-centric approach, the hydrothermal vent community appeared to be dominated by Proteobacteria, and Sulfurimonas was the most abundant genus. Metabolic reconstructions highlight a prominent role of formaldehyde oxidation and the reverse TCA cycle in carbon fixation. [NiFe]-hydrogenases seemed to constitute the preferred strategy to oxidize H, indicating that besides HS, H could be an essential electron donor in this system. Moreover, the sulfur cycle analysis showed a high abundance and diversity of sulfate reduction genes underpinning the HS production. This study covers the diversity and metabolic potential of the microbial soil community in Levante bay and adds to our understanding of the biogeochemistry of volcanic ecosystems.
Topics: Methane; Hydrogen; Italy; Sulfur; Metagenome; Soil Microbiology; Archaea; Bacteria; Hydrothermal Vents; Islands; Phylogeny
PubMed: 38954064
DOI: 10.1007/s10482-024-01995-5 -
Archives of Microbiology Jul 2024Wild-type Lactococcus lactis strain LAC460 secretes prophage-encoded bacteriocin-like lysin LysL, which kills some Lactococcus strains, but has no lytic effect on the...
Wild-type Lactococcus lactis strain LAC460 secretes prophage-encoded bacteriocin-like lysin LysL, which kills some Lactococcus strains, but has no lytic effect on the producer. LysL carries two N-terminal enzymatic active domains (EAD), and an unknown C-terminus without homology to known domains. This study aimed to determine whether the C-terminus of LysL carries a cell wall binding domain (CBD) for target specificity of LysL. The C-terminal putative CBD region of LysL was fused with His-tagged green fluorescent protein (HGFPuv). The HGFPuv_CBDlysL gene fusion was ligated into the pASG-IBA4 vector, and introduced into Escherichia coli. The fusion protein was produced and purified with affinity chromatography. To analyse the binding of HGFPuv_CBDLysL to Lactococcus cells, the protein was mixed with LysL-sensitive and LysL-resistant strains, including the LysL-producer LAC460, and the fluorescence of the cells was analysed. As seen in fluorescence microscope, HGFPuv_CBDLysL decorated the cell surface of LysL-sensitive L. cremoris MG1614 with green fluorescence, whereas the resistant L. lactis strains LM0230 and LAC460 remained unfluorescent. The fluorescence plate reader confirmed the microscopy results detecting fluorescence only from four tested LysL-sensitive strains but not from 11 tested LysL-resistant strains. Specific binding of HGFPuv_CBDLysL onto the LysL-sensitive cells but not onto the LysL-resistant strains indicates that the C-terminus of LysL contains specific CBD. In conclusion, this report presents experimental evidence of the presence of a CBD in a lactococcal phage lysin. Moreover, the inability of HGFPuv_CBDLysL to bind to the LysL producer LAC460 may partly explain the host's resistance to its own prophage lysin.
Topics: Lactococcus lactis; Cell Wall; Bacteriocins; Escherichia coli; Green Fluorescent Proteins; Protein Domains; Recombinant Fusion Proteins; Protein Binding
PubMed: 38954047
DOI: 10.1007/s00203-024-04066-5 -
Mikrochimica Acta Jul 2024A ratiometric SERS aptasensor based on catalytic hairpin self-assembly (CHA) mediated cyclic signal amplification strategy was developed for the rapid and reliable...
A ratiometric SERS aptasensor based on catalytic hairpin self-assembly (CHA) mediated cyclic signal amplification strategy was developed for the rapid and reliable determination of Escherichia coli O157:H7. The recognition probe was synthesized by modifying magnetic beads with blocked aptamers, and the SERS probe was constructed by functionalizing gold nanoparticles (Au NPs) with hairpin structured DNA and 4-mercaptobenzonitrile (4-MBN). The recognition probe captured E. coli O157:H7 specifically and released the blocker DNA, which activated the CHA reaction on the SERS probe and turned on the SERS signal of 6-carboxyl-x-rhodamine (ROX). Meanwhile, 4-MBN was used as an internal reference to calibrate the matrix interference. Thus, sensitive and reliable determination and quantification of E. coli O157:H7 was established using the ratio of the SERS signal intensities of ROX to 4-MBN. This aptasensor enabled detection of 2.44 × 10 CFU/mL of E. coli O157:H7 in approximately 3 h without pre-culture and DNA extraction. In addition, good reliability and excellent reproducibility were observed for the determination of E. coli O157:H7 in spiked water and milk samples. This study offered a new solution for the design of rapid, sensitive, and reliable SERS aptasensors.
Topics: Escherichia coli O157; Aptamers, Nucleotide; Metal Nanoparticles; Gold; Milk; Spectrum Analysis, Raman; Biosensing Techniques; Limit of Detection; Animals; Catalysis; Inverted Repeat Sequences; Food Contamination; Water Microbiology; Reproducibility of Results
PubMed: 38954045
DOI: 10.1007/s00604-024-06475-1 -
Current Microbiology Jul 2024Two Gram-stain-negative, facultative anaerobic, rod-shaped, motile bacterial strains, designated F26243 and F60267 were isolated from coastal sediment in Weihai, China....
Two Gram-stain-negative, facultative anaerobic, rod-shaped, motile bacterial strains, designated F26243 and F60267 were isolated from coastal sediment in Weihai, China. Strains F26243 and F60267 were grown at 4-40 °C (optimum 33 °C), pH 7.0-9.5 and pH 6.5-9.5 (optimum at pH 7.0), in the presence of 1.0-7.0% (w/v) NaCl (optimum 2.5%) and 1.0-12.0% (w/v) NaCl (optimum 2.0%), respectively. The 16S rRNA gene sequences phylogenetic analysis showed that strains F26243 and F60267 are closely related to the genus Marinobacter and exhibited the highest sequence similarities to Marinobacter salexigens HJR7 (97.7% and 98.0%, respectively), the similarity between two isolates was 96.7%. Strains F26243 and F60267 displayed genomic DNA G + C content of 53.6% and 53.8%, respectively. When compared to the M. salexigens HJR7, the average nucleotide identity (ANI) values were 83.7% and 84.1%, and the percentage of conserved proteins (POCP) values were 79.9% and 84.6%, respectively. Ubiquinone 9 (Q-9) was the only respiratory quinone detected in both isolates. The major cellular fatty acids (> 10.0%) were summed feature 3 (comprising Cω7c and/or Cω6c), C and Cω9c. The polar lipid profiles of strains F26243 and F60267 contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, phosphatidylglycerol, aminophospholipid and one unidentified phospholipid. Based on genomic characteristics, phenotypic and chemotaxonomic, strains F26243 and F60267 represent two novel species of the genus Marinobacter, for which the names Marinobacter sediminicola sp. nov. and Marinobacter xiaoshiensis sp. nov. are proposed, the type strains are F26243 (= KCTC 92640 = MCCC 1H01345) and F60267 (= KCTC 92638 = MCCC 1H01346).
Topics: Marinobacter; Geologic Sediments; Phylogeny; RNA, Ribosomal, 16S; Base Composition; Fatty Acids; DNA, Bacterial; China; Bacterial Typing Techniques; Phospholipids; Sequence Analysis, DNA; Seawater
PubMed: 38954028
DOI: 10.1007/s00284-024-03782-x -
Applied Microbiology and Biotechnology Jul 20242-Keto-3-deoxy-galactonate (KDGal) serves as a pivotal metabolic intermediate within both the fungal D-galacturonate pathway, which is integral to pectin catabolism, and... (Review)
Review
2-Keto-3-deoxy-galactonate (KDGal) serves as a pivotal metabolic intermediate within both the fungal D-galacturonate pathway, which is integral to pectin catabolism, and the bacterial DeLey-Doudoroff pathway for D-galactose catabolism. The presence of KDGal enantiomers, L-KDGal and D-KDGal, varies across these pathways. Fungal pathways generate L-KDGal through the reduction and dehydration of D-galacturonate, whereas bacterial pathways produce D-KDGal through the oxidation and dehydration of D-galactose. Two distinct catabolic routes further metabolize KDGal: a nonphosphorolytic pathway that employs aldolase and a phosphorolytic pathway involving kinase and aldolase. Recent findings have revealed that L-KDGal, identified in the bacterial catabolism of 3,6-anhydro-L-galactose, a major component of red seaweeds, is also catabolized by Escherichia coli, which is traditionally known to be catabolized by specific fungal species, such as Trichoderma reesei. Furthermore, the potential industrial applications of KDGal and its derivatives, such as pyruvate and D- and L-glyceraldehyde, are underscored by their significant biological functions. This review comprehensively outlines the catabolism of L-KDGal and D-KDGal across different biological systems, highlights stereospecific methods for discriminating between enantiomers, and explores industrial application prospects for producing KDGal enantiomers. KEY POINTS: • KDGal is a metabolic intermediate in fungal and bacterial pathways • Stereospecific enzymes can be used to identify the enantiomeric nature of KDGal • KDGal can be used to induce pectin catabolism or produce functional materials.
Topics: Sugar Acids; Metabolic Networks and Pathways; Galactose; Fungi; Bacteria; Escherichia coli; Stereoisomerism
PubMed: 38954014
DOI: 10.1007/s00253-024-13235-x -
Archives of Microbiology Jul 2024Salmonella is considered as one of the most common zoonotic /foodborne pathogens in the world. The application of bacteriophages as novel antibacterial agents in food...
Salmonella is considered as one of the most common zoonotic /foodborne pathogens in the world. The application of bacteriophages as novel antibacterial agents in food substrates has become an emerging strategy. Bacteriophages have the potential to control Salmonella contamination.We have isolated and characterized a broad-spectrum Salmonella phage, SP154, which can lyse 9 serotypes, including S. Enteritidis, S. Typhimurium, S. Pullorum, S. Arizonae, S. Dublin, S. Cholerasuis, S. Chester, S. 1, 4, [5], 12: i: -, and S. Derby, accounting for 81.9% of 144 isolates. SP154 showed a short latent period (40 min) and a high burst size (with the first rapid burst size at 107 PFUs/cell and the second rapid burst size at approximately 40 PFUs/cell). Furthermore, SP154 activity has higher survival rates across various environmental conditions, including pH 4.0-12.0 and temperatures ranging from 4 to 50 °C for 60 min, making it suitable for diverse food processing and storage applications. Significant reductions in live Salmonella were observed in different foods matrices such as milk and chicken meat, with a decrease of up to 1.9 log CFU/mL in milk contamination and a 1 log CFU/mL reduction in chicken meat. Whole genome sequencing analysis revealed that SP154 belongs to the genus Ithacavirus, subfamily Humphriesvirinae, within the family Schitoviridae. Phylogenetic analysis based on the terminase large subunit supported this classification, although an alternate tree using the tail spike protein gene suggested affiliation with the genus Kuttervirus, underscoring the limitations of relying on a single gene for phylogenetic inference. Importantly, no virulence or antibiotic resistance genes were detected in SP154. Our research highlights the potential of using SP154 for biocontrol of Salmonella in the food industry.
Topics: Salmonella Phages; Whole Genome Sequencing; Animals; Salmonella; Genome, Viral; Food Microbiology; Chickens; Milk; Meat; Phylogeny
PubMed: 38953983
DOI: 10.1007/s00203-024-04061-w -
Applied and Environmental Microbiology Jul 2024sp. ATCC 39006 is an important model strain for the study of prodigiosin production, whose prodigiosin biosynthesis genes () are arranged in an operon. Several...
UNLABELLED
sp. ATCC 39006 is an important model strain for the study of prodigiosin production, whose prodigiosin biosynthesis genes () are arranged in an operon. Several transcription factors have been shown to control the transcription of the operon. However, since the regulation of prodigiosin biosynthesis is complex, the regulatory mechanism for this process has not been well established. In most γ-proteobacteria, the ROK family regulator NagC acts as a global transcription factor in response to -acetylglucosamine (GlcNAc). In sp. ATCC 39006, NagC represses the transcription of two divergent operons, and , which encode proteins involved in the transport and metabolism of GlcNAc. Moreover, NagC directly binds to a 21-nt region that partially overlaps the -10 and -35 regions of the promoter and promotes the transcription of prodigiosin biosynthesis genes, thereby increasing prodigiosin production. Although NagC still acts as both repressor and activator in sp. ATCC 39006, its transcriptional regulatory activity is independent of GlcNAc. NagC was first found to regulate antibiotic biosynthesis in Gram-negative bacteria, and NagC-mediated regulation is not responsive to GlcNAc, which contributes to future studies on the regulation of secondary metabolism by NagC in other bacteria.
IMPORTANCE
The ROK family transcription factor NagC is an important global regulator in the γ-proteobacteria. A large number of genes involved in the transport and metabolism of sugars, as well as those associated with biofilm formation and pathogenicity, are regulated by NagC. In all of these regulations, the transcriptional regulatory activity of NagC responds to the supply of GlcNAc in the environment. Here, we found for the first time that NagC can regulate antibiotic biosynthesis, whose transcriptional regulatory activity is independent of GlcNAc. This suggests that NagC may respond to more signals and regulate more physiological processes in Gram-negative bacteria.
PubMed: 38953369
DOI: 10.1128/aem.00891-24 -
Food & Function Jul 2024Edible plant-derived nanovesicles (ePDNs) have shown potential as a non-pharmacological option for inflammatory bowel disease (IBD) by maintaining gut health and showing...
Edible plant-derived nanovesicles (ePDNs) have shown potential as a non-pharmacological option for inflammatory bowel disease (IBD) by maintaining gut health and showing anti-inflammatory effects. However, the effects of -derived nanovesicles (ADNs) on colitis have not been studied to date. Here, we extracted exosome-like nanovesicles from and investigated whether they have an anti-inflammatory effect in RAW 264.7 cells and colitis mice. The results showed that ADNs reduced the elevated levels of inflammatory factors such as IL-1β, IL-6, TNF-α, and NF-κB pathway-related proteins as a consequence of lipopolysaccharide (LPS) stimulation in RAW 264.7 cells. Furthermore, our mouse experiments demonstrated that ADNs could ameliorate dextran sulfate sodium (DSS)-induced colitis symptoms (, increased disease activity index score, intestinal permeability, and histological appearance). Additionally, ADNs counteracted DSS-induced colitis by downregulating the expression of serum amyloid A (SAA), IL-1β, IL-6, and TNF-α and increasing the expression of tight junction proteins (ZO-1 and occludin) and the anti-inflammatory cytokine IL-10. 16S rRNA gene sequencing showed that ADN intervention restored the gut microbial composition, which was similar to that of the DSS non-treated group, by decreasing the ratio of to and the relative abundance of . Furthermore, ADNs induced acetic acid production along with an increase in the abundance of . Overall, our findings suggest that ADN supplementation has a crucial role in maintaining gut health and is a novel preventive therapy for IBD.
PubMed: 38953279
DOI: 10.1039/d4fo01366b -
Zhongguo Yi Xue Ke Xue Yuan Xue Bao.... Jun 2024(Hp) is a common Gram-negative bacillus causing gastrointestinal infections.It mainly exists on the surface of gastric epithelial cells and in mucus and is associated... (Review)
Review
(Hp) is a common Gram-negative bacillus causing gastrointestinal infections.It mainly exists on the surface of gastric epithelial cells and in mucus and is associated with gastric ulcers,gastric cancer,and gastric mucosa-associated lymphomas.Studies have shown that Hp can induce or exacerbate certain extragastric diseases and is associated with the occurrence of coronavirus disease 2019.It is hypothesized that Hp may be indirectly or directly involved in the occurrence and development of diseases by stimulating the production of inflammatory cytokines or inducing cross-immune reactions.In addition,Hp can enter to release toxins continuously and play a role in escaping the recognition of the host immune system and the bactericidal effect of drugs.This article reviews the research progress in Hp-associated extragastric diseases in recent years,aiming to draw the attention of clinical workers to Hp-associated extragastric diseases and enrich the knowledge about Hp infection for formulating countermeasures to avoid the aggravation or triggering of other diseases by Hp.
Topics: Humans; Helicobacter pylori; Helicobacter Infections; COVID-19
PubMed: 38953266
DOI: 10.3881/j.issn.1000-503X.15698 -
PeerJ 2024Potato farming is a vital component of food security and the economic stability especially in the under developing countries but it faces many challenges in production,...
Potato farming is a vital component of food security and the economic stability especially in the under developing countries but it faces many challenges in production, blackleg disease caused by () is one of the main reason for damaging crop yield of the potato. Effective management strategies are essential to control these losses and to get sustainable potato crop yield. This study was focused on characterizing the and the investigating new chemical options for its management. The research was involved a systematic survey across the three district of Punjab, Pakistan (Khanewal, Okara, and Multan) to collect samples exhibiting the black leg symptoms. These samples were analyzed in the laboratory where gram-negative bacteria were isolated and identified through biochemical and pathogenicity tests for . DNA sequencing further confirmed these isolates of strains. Six different chemicals were tested to control blackleg problem in both and at different concentrations. experiment, Cordate demonstrated the highest efficacy with a maximum inhibition zones of 17.139 mm, followed by Air One (13.778 mm), Profiler (10.167 mm), Blue Copper (7.7778 mm), Spot Fix (7.6689 mm), and Strider (7.0667 mm). , Cordate maintained its effectiveness with the lowest disease incidence of 14.76%, followed by Blue Copper (17.49%), Air One (16.98%), Spot Fix (20.67%), Profiler (21.45%), Strider (24.99%), and the control group (43.00%). The results highlight Cordate's potential as a most effective chemical against , offering promising role for managing blackleg disease in potato and to improve overall productivity.
Topics: Solanum tuberosum; Pectobacterium; Plant Diseases; Pakistan
PubMed: 38952990
DOI: 10.7717/peerj.17518