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Metabolites Jan 2023GM16 associates with , a model plant in biofuel production. releases abundant phenolic glycosides such as salicin, but GM16 cannot utilize salicin, whereas strains...
GM16 associates with , a model plant in biofuel production. releases abundant phenolic glycosides such as salicin, but GM16 cannot utilize salicin, whereas strains are known to utilize compounds similar to the aglycone moiety of salicin-salicyl alcohol. We propose that the association of to is mediated by another organism (such as OV744) that degrades the glucosyl group of salicin. In this study, we demonstrate that in the - salicin co-culture model, grows by degrading salicin to glucose 6-phosphate and salicyl alcohol which is secreted out and is subsequently utilized by GM16 for its growth. Using various quantitative approaches, we elucidate the individual pathways for salicin and salicyl alcohol metabolism present in and , respectively. Furthermore, we were able to establish that the salicyl alcohol cross-feeding interaction between the two strains on salicin medium is carried out through the combination of their respective individual pathways. The research presents one of the potential advantages of salicyl alcohol release by strains such as , and how phenolic glycosides could be involved in attracting multiple types of bacteria into the microbiome.
PubMed: 36837758
DOI: 10.3390/metabo13020140 -
PloS One 2017Rahnella aquatilis is ubiquitous and its certain strains have the applicative potent as a plant growth-promoting rhizobacteria. R. aquatilis HX2 is a biocontrol agent to...
BACKGROUND
Rahnella aquatilis is ubiquitous and its certain strains have the applicative potent as a plant growth-promoting rhizobacteria. R. aquatilis HX2 is a biocontrol agent to produce antibacterial substance (ABS) and showed efficient biocontrol against crown gall caused by Agrobacterium vitis on sunflower and grapevine plants. The regulatory network of the ABS production and biocontrol activity is still limited known.
METHODOLOGY/PRINCIPAL FINDINGS
In this study, a transposon-mediated mutagenesis strategy was used to investigate the regulators that involved in the biocontrol activity of R. aquatilis HX2. A 366-nt noncoding RNA CsrB was identified in vitro and in vivo, which regulated ABS production and biocontrol activity against crown gall on sunflower plants, respectively. The predicted product of noncoding RNA CsrB contains 14 stem-loop structures and an additional ρ-independent terminator harpin, with 23 characteristic GGA motifs in the loops and other unpaired regions. CsrB is required for ABS production and biocontrol activity in the biocontrol regulation by a two-component regulatory system BarA/UvrY in R. aquatilis HX2.
CONCLUSION/SIGNIFICANCE
The noncoding RNA CsrB regulates BarA-dependent ABS production and biocontrol activity in R. aquatilis HX2. To the best of our knowledge, this is the first report of noncoding RNA as a regulator for biocontrol function in R. aquatilis.
Topics: Bacterial Proteins; Pest Control, Biological; Plant Diseases; RNA; RNA, Bacterial; RNA, Untranslated; Rahnella
PubMed: 29091941
DOI: 10.1371/journal.pone.0187492 -
Multi-omics analysis of miRNA-mediated intestinal microflora changes in crucian carp infected with .Frontiers in Immunology 2024Infection by an emerging bacterial pathogen caused enteritis and septicemia in fish. However, the molecular pathogenesis of enteritis induced by infection and its...
Infection by an emerging bacterial pathogen caused enteritis and septicemia in fish. However, the molecular pathogenesis of enteritis induced by infection and its interacting mechanism of the intestinal microflora associated with microRNA (miRNA) immune regulation in crucian carp are still unclear. In this study, intraperitoneally injected with KCL-5 was used as an experimental animal model, and the intestinal pathological changes, microflora, and differentially expressed miRNAs (DEMs) were investigated by multi-omics analysis. The significant changes in histopathological features, apoptotic cells, and enzyme activities (e.g., lysozyme (LYS), alkaline phosphatase (AKP), alanine aminotransferase (ALT), aspartate transaminase (AST), and glutathione peroxidase (GSH-Px)) in the intestine were examined after infection. Diversity and composition analysis of the intestinal microflora clearly demonstrated four dominant bacteria: Proteobacteria, Fusobacteria, Bacteroidetes, and Firmicutes. A total of 87 DEMs were significantly screened, and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that the potential target genes were mainly involved in the regulation of lipid, glutathione, cytosine, and purine metabolism, which participated in the local immune response through the intestinal immune network for IgA production, lysosome, and Toll-like receptor (TLR) pathways. Moreover, the expression levels of 11 target genes (e.g., , , , , , , , , , , and ) related to inflammation and immunity were verified by qRT-PCR detection. The correlation analysis indicated that the abundance of intestinal Firmicutes and Proteobacteria was significantly associated with the high local expression of miR-203/, miR-129/, and miR-205/. These findings will help to elucidate the molecular regulation mechanism of the intestinal microflora, inflammation, and immune response-mediated miRNA-target gene axis in cyprinid fish.
Topics: Animals; Goldfish; Carps; Rahnella; NF-kappa B; Multiomics; Gastrointestinal Microbiome; Tumor Necrosis Factor-alpha; Inflammation; Enteritis; Transforming Growth Factor beta; MicroRNAs
PubMed: 38426108
DOI: 10.3389/fimmu.2024.1335602 -
Microbiome Jan 2018Britain's native oak species are currently under threat from acute oak decline (AOD), a decline-disease where stem bleeds overlying necrotic lesions in the inner bark...
BACKGROUND
Britain's native oak species are currently under threat from acute oak decline (AOD), a decline-disease where stem bleeds overlying necrotic lesions in the inner bark and larval galleries of the bark-boring beetle, Agrilus biguttatus, represent the primary symptoms. It is known that complex interactions between the plant host and its microbiome, i.e. the holobiont, significantly influence the health status of the plant. In AOD, necrotic lesions are caused by a microbiome shift to a pathobiome consisting predominantly of Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana and potentially other bacteria. However, the specific mechanistic processes of the microbiota causing tissue necrosis, and the host response, have not been established and represent a barrier to understanding and managing this decline.
RESULTS
We profiled the metagenome, metatranscriptome and metaproteome of inner bark tissue from AOD symptomatic and non-symptomatic trees to characterise microbiota-host interactions. Active bacterial virulence factors such as plant cell wall-degrading enzymes, reactive oxygen species defence and flagella in AOD lesions, along with host defence responses including reactive oxygen species, cell wall modification and defence regulators were identified. B. goodwinii dominated the lesion microbiome, with significant expression of virulence factors such as the phytopathogen effector avrE. A smaller proportion of microbiome activity was attributed to G. quercinecans and R. victoriana. In addition, we describe for the first time the potential role of two previously uncharacterised Gram-positive bacteria predicted from metagenomic binning and identified as active in the AOD lesion metatranscriptome and metaproteome, implicating them in lesion formation.
CONCLUSIONS
This multi-omic study provides novel functional insights into microbiota-host interactions in AOD, a complex arboreal decline disease where polymicrobial-host interactions result in lesion formation on tree stems. We present the first descriptions of holobiont function in oak health and disease, specifically, the relative lesion activity of B. goodwinii, G. quercinecans, Rahnella victoriana and other bacteria. Thus, the research presented here provides evidence of some of the mechanisms used by members of the lesion microbiome and a template for future multi-omic research into holobiont characterisation, plant polymicrobial diseases and pathogen defence in trees.
Topics: Bacterial Proteins; Enterobacteriaceae; Gene Expression Profiling; Genomics; Host-Pathogen Interactions; Microbiota; Plant Diseases; Proteomics; Quercus; Sequence Analysis, DNA; Sequence Analysis, RNA; Virulence Factors
PubMed: 29378627
DOI: 10.1186/s40168-018-0408-5 -
Case Reports in Pediatrics 2015Rahnella aquatilis is an infrequently isolated Gram-negative rod within the Enterobacteriaceae family. The organism's natural habitat is water. The organism is rarely...
Rahnella aquatilis is an infrequently isolated Gram-negative rod within the Enterobacteriaceae family. The organism's natural habitat is water. The organism is rarely isolated from clinical specimens and it seldom causes infection in immunocompetent individuals. Here we present a one-month-old boy who was born prematurely at 27th week of gestation by cesarean section with a birth weight of 730 g. He developed sepsis caused by Rahnella aquatilis during the treatment for ventilator associated pneumonia due to Stenotrophomonas maltophilia with ciprofloxacin. He was successfully treated with a combination of amikacin plus meropenem. Although R. aquatilis is one of the saprophyticus organisms, it may cause life-threatening infection in newborn.
PubMed: 26090257
DOI: 10.1155/2015/860671 -
International Journal of Food Science 2022Eggs constitute an important part of the Moroccan diet. However, contaminated eggs can cause a serious public health problem if consumed undercooked, uncooked, or used...
Eggs constitute an important part of the Moroccan diet. However, contaminated eggs can cause a serious public health problem if consumed undercooked, uncooked, or used in unpasteurized egg foodstuffs. This study was carried out to evaluate the microbial contents of eggs according to their sales sector in Morocco. For that, a total of 1770 eggs were collected from January to September 2021 from formal markets (refrigerated eggs from large shopping centers) and informal markets (eggs at ambient temperature from ambulatory sellers, street vendors, kiosks, and neighborhood stores) and transferred to the Avian Pathology Unit at Hassan II Agronomic and Veterinary Institute. The eggshells and their contents were tested separately; swabs of eggshells were used to inoculate Mac-Conkey agar, while the egg contents were cultured on Mac-Conkey and Mannitol salt agar, then standard microbiological tests were performed to identify the isolated organisms. The results showed that informal eggs were more contaminated (87%) than formal eggs (48) ( < 0.05). The bacteria isolated from the eggshells (informal and formal) were (59% and 21%), spp. (24% and 4%), (17% and 8%), (9% and 1%), spp. (9% and1%), (9% and 1%), spp. (5% and 0%), (0% and 2%), spp. (4% and 0%), (2% and 0%), (1% and 0%), and (0% and 1%). For the egg-contents, the detected bacteria (informal and formal) were (14% and 28%), spp. (7% and 6%), (6% and 1%), (4% and 4%), (4%, 1%), spp. (4%, 0%), (3% and 1%), (2% and 0%), spp. (1% and 6%), spp. (1% and 3%), and (1% and 0%). We conclude that eggs might be contaminated with several bacteria and can constitute a public health threat in Morocco.
PubMed: 36245565
DOI: 10.1155/2022/6223404 -
Journal of Dairy Science Mar 2024Ropy defect of pasteurized fluid milk is a type of spoilage which manifests itself by an increased viscosity, slimy body, and string-like flow during pouring. This...
Phenotypic and genomic characterizations of Klebsiella pneumoniae ssp. pneumoniae and Rahnella inusitata strains reveal no clear association between genetic content and ropy phenotype.
Ropy defect of pasteurized fluid milk is a type of spoilage which manifests itself by an increased viscosity, slimy body, and string-like flow during pouring. This defect has, among other causes, been attributed to the growth, proliferation and exopolysaccharide production by coliform bacteria, which are most commonly introduced in milk as post-pasteurization contaminants. As we identified both Klebsiella pneumoniae ssp. pneumoniae and Rahnella inusitata that were linked to a ropy defect, the goal of this study was to characterize 3 K. pneumoniae ssp. pneumoniae strains and 2 R. inusitata for (1) their ability to grow and cause ropy defect in milk at 6°C and 21°C and to (2) probe the genetic basis for observed ropy phenotype. Although all K. pneumoniae ssp. pneumoniae and R. inusitata strains showed net growth of >4 log over 48 h in UHT milk at 21°C, only R. inusitata strains displayed growth during 28-d incubation period at 6°C (>6 log). Two out of 3 K. pneumoniae ssp. pneumoniae strains were capable of causing the ropy defect in milk at 21°C, as supported by an increase in the viscosity of milk and string-like flow during pouring; these 2 strains were originally isolated from raw milk. Only one R. inusitata strains was able to cause the ropy defect in milk; this strain was able to cause the defect at both 6°C and 21°C, and was originally isolated from a pasteurized milk. These findings suggest that the potential of K. pneumoniae ssp. pneumoniae and R. inusitata to cause ropy defect in milk is a strain-dependent characteristic. Comparative genomics provided no definitive answer on genetic basis for the ropy phenotype. However, for K. pneumoniae ssp. pneumoniae, genes rffG, rffH, rfbD, and rfbC involved in biosynthesis and secretion of enterobacterial common antigen (ECA) could only be found in the 2 strains that produced ropy defect, and for R. inusitata a set of 2 glycosyltransferase- and flippase genes involved in nucleotide sugar biosynthesis and export could only be identified in the ropy strain. Although these results provide some initial information for potential markers for strains that can cause ropy milk, the relationship between genetic content and ropiness in milk remains poorly understood and merits further investigation.
Topics: Animals; Klebsiella pneumoniae; Genomics; Klebsiella; Rahnella
PubMed: 37944807
DOI: 10.3168/jds.2023-23922 -
Applied and Environmental Microbiology Nov 2009Rahnella aquatilis HX2, a biocontrol agent for grapevine crown gall caused by Agrobacterium vitis, produces an antibacterial substance that inhibits the growth of A....
Mutations that disrupt either the pqq or the gdh gene of Rahnella aquatilis abolish the production of an antibacterial substance and result in reduced biological control of grapevine crown gall.
Rahnella aquatilis HX2, a biocontrol agent for grapevine crown gall caused by Agrobacterium vitis, produces an antibacterial substance that inhibits the growth of A. vitis in vitro. In this study, we show that MH15 and MH16, two Tn5-induced mutants of HX2, have lost their abilities to inhibit A. vitis and have reduced biocontrol activities; they grow in logarithmic phase at a rate similar to that of the wild type and have single Tn5 insertions. They are also impaired in producing pyrroloquinoline quinone (PQQ) or glucose dehydrogenase (GDH). Complementation of MH15 and MH16 with cosmid clones of CP465 and CP104 from an HX2 DNA library restored the antibiosis, biocontrol, and PQQ or GDH production phenotypes. A 6.7-kb BamHI fragment from CP465 that fully restored the MH15-affected phenotypes was cloned and sequenced. Sequence analysis of the mutated DNA region resulted in the identification of seven open reading frames (ORFs), six of which share significant homology with PQQ-synthesizing genes in other bacteria, designated pqqA through pqqF. Meanwhile, A 5.5-kb PstI fragment from CP104 fully complemented the MH16 mutant and contained a single ORF highly similar to that of genes coding for GDHs. An in-frame gdh deletion mutant has the same phenotypes as the Tn5 mutant of MH16. Complementation of both deletion and Tn5 gdh mutants restored the affected phenotypes to wild-type levels. Our results suggest that an antibacterial substance plays a role in biocontrol of A. vitis by HX2.
Topics: Amino Acid Sequence; Anti-Bacterial Agents; Antibiosis; DNA Transposable Elements; DNA, Bacterial; Gene Deletion; Gene Order; Genetic Complementation Test; Glucose Dehydrogenases; Molecular Sequence Data; Mutagenesis, Insertional; Open Reading Frames; PQQ Cofactor; Pest Control, Biological; Plant Tumors; Rahnella; Sequence Alignment; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Synteny; Vitis
PubMed: 19734331
DOI: 10.1128/AEM.00902-09 -
Royal Society Open Science Nov 2023Enterobacterales of clinical importance for humans and domestic animals are now commonly detected among wildlife worldwide. However, few studies have investigated their...
Enterobacterales of clinical importance for humans and domestic animals are now commonly detected among wildlife worldwide. However, few studies have investigated their prevalence among bats, particularly in bat species living near humans. In this study, we assessed the occurrence of Extended-spectrum beta-lactamase-producing (ESBL) and carbapenemase-resistant (CR) Enterobacterales in rectal swabs of bats submitted to the Chilean national rabies surveillance program from 2021 to 2022. From the 307 swabs screened, 47 (15%) harboured cefotaxime-resistant Enterobacterales. Bats carrying these bacteria originated from 9 out of the 14 Chilean regions. Most positive samples were obtained from ( = 42), but also , and . No Enterobacterales were resistant to imipenem. All ESBL-Enterobacterales were confirmed as by MALDI-TOF. No other ESBL or CR Enterobacterales were detected. To our knowledge, this is the first screening of antibiotic-resistant bacteria in wild bats of Chile, showing the bat faecal carriage of naturally resistant to cephalosporins, but also including acquired resistance to important antibiotics for public health such as amoxicillin with clavulanic acid. Our results suggest unknown selective pressures on , but low or no carriage of ESBL or CR and spp. Future studies should assess the zoonotic and environmental implications of , which are likely present in the guano left by bats roosting in human infrastructures.
PubMed: 38026036
DOI: 10.1098/rsos.231177 -
PloS One 2023A range of analytical methods (GC-MS, LC-MS, voltammetry, microbiological and microscopic techniques, PCR) was used to assay a range of potential chemical and biological...
A range of analytical methods (GC-MS, LC-MS, voltammetry, microbiological and microscopic techniques, PCR) was used to assay a range of potential chemical and biological contaminants in soil and dandelion samples. The results provide the first comprehensive safety analysis of dandelion as a herbal product. Samples were collected from three different sites in Poland where the local population collects dandelion plants for their own consumption: Rudenka (a mountain meadow in the European Ecological Network of Natura 2000 protection area, free of agrotechnical treatments for over 30 years), Warszawa 1 (dense single-family housing with heavy traffic), and Warszawa 2 (recreation area with heavy traffic near a coal-fired heat and power plant). The assays of heavy metals and other chemical pollutants (PAHs, PCBs, dioxins, pesticides, mycotoxins) confirm that all collected soil and dandelion samples were chemically pure; however, 95 species of pathogenic bacteria were detected, including "carnivorous" Vibrio vulnificus, zoonotic Pasteurella pneumotropica, Pasteurella canis, Staphylococcus pseudintermedius, Staphylococcus lentus and Francisella tularensis as well as 14 species of pathogenic fungi and one protozoan parasite (Giardia intestinalis). The discovery of septicemia agents V. vulnificus, Fusobacterium mortiferum and Rahnella aquatilis in the soil surrounding dandelion roots and in the flowers, G. intestinalis in dandelion leaves and roots samples, all collected in Warsaw, is highly disturbing. This finding underlines the need for increased caution when collecting dandelion in densely populated areas with a large population of pets. Thorough washing of the harvested plants is necessary before using them for consumption, especially in the case of making salads from fresh dandelion leaves, which is becoming increasingly popular among people leading healthy and an environmentally friendly lifestyle.
Topics: Humans; Taraxacum; Environmental Pollutants; Soil; Metals, Heavy; Plant Leaves; Soil Pollutants
PubMed: 36662824
DOI: 10.1371/journal.pone.0280810