scholarly journals Adaption and Degradation Strategies of Methylotrophic 1,4-Dioxane Degrading Strain Xanthobacter sp. YN2 Revealed by Transcriptome-Scale Analysis

2021 ◽  
Vol 22 (19) ◽  
pp. 10435
Author(s):  
Yingning Wang ◽  
Fang Ma ◽  
Jixian Yang ◽  
Haijuan Guo ◽  
Delin Su ◽  
...  

Biodegradation of 1,4-dioxane (dioxane) contamination has gained much attention for decades. In our previous work, we isolated a highly efficient dioxane degrader, Xanthobacter sp. YN2, but the underlying mechanisms of its extraordinary degradation performance remained unresolved. In this study, we performed a comparative transcriptome analysis of YN2 grown on dioxane and citrate to elucidate its genetic degradation mechanism and investigated the transcriptomes of different dioxane degradation stages (T0, T24, T48). We also analyzed the transcriptional response of YN2 over time during which the carbon source switched from citrate to dioxane. The results indicate that strain YN2 was a methylotroph, which provides YN2 a major advantage as a pollutant degrader. A large number of genes involved in dioxane metabolism were constitutively expressed prior to dioxane exposure. Multiple genes related to the catabolism of each intermediate were upregulated by treatment in response to dioxane. Glyoxylate metabolism was essential during dioxane degradation by YN2, and the key intermediate glyoxylate was metabolized through three routes: glyoxylate carboligase pathway, malate synthase pathway, and anaplerotic ethylmalonyl–CoA pathway. Genes related to quorum sensing and transporters were significantly upregulated during the early stages of degradation (T0, T24) prior to dioxane depletion, while the expression of genes encoding two-component systems was significantly increased at late degradation stages (T48) when total organic carbon in the culture was exhausted. This study is the first to report the participation of genes encoding glyoxalase, as well as methylotrophic genes xoxF and mox, in dioxane metabolism. The present study reveals multiple genetic and transcriptional strategies used by YN2 to rapidly increase biomass during growth on dioxane, achieve high degradation efficiency and tolerance, and adapt to dioxane exposure quickly, which provides useful information regarding the molecular basis for efficient dioxane biodegradation.

2019 ◽  
Vol 95 (8) ◽  
Author(s):  
Kapudeep Karmakar ◽  
Abhilash Vijay Nair ◽  
Giridhar Chandrasekharan ◽  
Preeti Garai ◽  
Utpal Nath ◽  
...  

ABSTRACTSalmonella is an established pathogen of the members of the kingdom Animalia. Reports indicate that the association of Salmonella with fresh, edible plant products occurs at the pre-harvest state, i.e. in the field. In this study, we follow the interaction of Salmonella Typhimurium with the model plant Arabidopsis thaliana to understand the process of migration in soil. Plant factors like root exudates serve as chemo-attractants. Our ex situ experiments allowed us to track Salmonella from its free-living state to the endophytic state. We found that genes encoding two-component systems and proteins producing extracellular polymeric substances are essential for Salmonella to adhere to the soil and roots. To understand the trans-kingdom flow of Salmonella, we fed the contaminated plants to mice and observed that it invades and colonizes liver and spleen. To complete the disease cycle, we re-established the infection in plant by mixing the potting mixture with the fecal matter collected from the diseased animals. Our experiments revealed a cross-kingdom invasion by the pathogen via passage through a murine intermediate, a mechanism for its persistence in the soil and invasion in a non-canonical host. These results form a basis to break the life-cycle of Salmonella before it reaches its animal host and thus reduce Salmonella contamination of food products.


Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2313-2325 ◽  
Author(s):  
Antonio J. Martín-Galiano ◽  
Jerry M. Wells ◽  
Adela G. de la Campa

A codon-profile strategy was used to predict gene expression levels in Streptococcus pneumoniae. Predicted highly expressed (PHE) genes included those encoding glycolytic and fermentative enzymes, sugar-conversion systems and carbohydrate-transporters. Additionally, some genes required for infection that are involved in oxidative metabolism and hydrogen peroxide production were PHE. Low expression values were predicted for genes encoding specific regulatory proteins like two-component systems and competence genes. Correspondence analysis localized 484 ORFs which shared a distinctive codon profile in the right horn. These genes had a mean G+C content (33·4 %) that was lower than the bulk of the genome coding sequences (39·7 %), suggesting that many of them were acquired by horizontal transfer. Half of these genes (242) were pseudogenes, ORFs shorter than 80 codons or without assigned function. The remaining genes included several virulence factors, such as capsular genes, iga, lytB, nanB, pspA, choline-binding proteins, and functions related to DNA acquisition, such as restriction-modification systems and comDE. In order to compare predicted translation rate with the relative amounts of mRNA for each gene, the codon adaptation index (CAI) values were compared with microarray fluorescence intensity values following hybridization of labelled RNA from laboratory-grown cultures. High mRNA amounts were observed in 32·5 % of PHE genes and in 64 % of the 25 genes with the highest CAI values. However, high relative amounts of RNA were also detected in 10·4 % of non-PHE genes, such as those encoding fatty acid metabolism enzymes and proteases, suggesting that their expression might also be regulated at the level of transcription or mRNA stability under the conditions tested. The effects of codon bias and mRNA amount on different gene groups in S. pneumoniae are discussed.


2008 ◽  
Vol 75 (3) ◽  
pp. 837-841 ◽  
Author(s):  
M. I. Klein ◽  
S. Duarte ◽  
J. Xiao ◽  
S. Mitra ◽  
T. H. Foster ◽  
...  

ABSTRACT The interaction of sucrose and starch with bacterial glucosyltransferases and human salivary amylase may enhance the pathogenic potential of Streptococcus mutans within biofilms by influencing the structural organization of the extracellular matrix and modulating the expression of genes involved in exopolysaccharide synthesis and specific sugar transport and two-component systems.


2005 ◽  
Vol 49 (5) ◽  
pp. 1915-1926 ◽  
Author(s):  
Janine T. Lin ◽  
Mariah Bindel Connelly ◽  
Chris Amolo ◽  
Suzie Otani ◽  
Debbie S. Yaver

ABSTRACT Global gene expression patterns of Bacillus subtilis in response to subinhibitory concentrations of protein synthesis inhibitors (chloramphenicol, erythromycin, and gentamicin) were studied by DNA microarray analysis. B. subtilis cultures were treated with subinhibitory concentrations of protein synthesis inhibitors for 5, 15, 30, and 60 min, and transcriptional patterns were measured throughout the time course. Three major classes of genes were affected by the protein synthesis inhibitors: genes encoding transport/binding proteins, genes involved in protein synthesis, and genes involved in the metabolism of carbohydrates and related molecules. Similar expression patterns for a few classes of genes were observed due to treatment with chloramphenicol (0.4× MIC) or erythromycin (0.5× MIC), whereas expression patterns of gentamicin-treated cells were distinct. Expression of genes involved in metabolism of amino acids was altered by treatment with chloramphenicol and erythromycin but not by treatment with gentamicin. Heat shock genes were induced by gentamicin but repressed by chloramphenicol. Other genes induced by the protein synthesis inhibitors included the yheIH operon encoding ABC transporter-like proteins, with similarity to multidrug efflux proteins, and the ysbAB operon encoding homologs of LrgAB that function to inhibit cell wall cleavage (murein hydrolase activity) and convey penicillin tolerance in Staphylococcus aureus.


2005 ◽  
Vol 187 (23) ◽  
pp. 8205-8210 ◽  
Author(s):  
Wolfgang Haas ◽  
Deepak Kaushal ◽  
Jack Sublett ◽  
Caroline Obert ◽  
Elaine I. Tuomanen

ABSTRACT The vancomycin stress response was studied in Streptococcus pneumoniae strains T4 (TIGR4) and Tupelo. Vancomycin affected the expression of 175 genes, including genes encoding transport functions and enzymes involved in aminosugar metabolism. The two-component systems TCS03, TCS11, and CiaRH also responded to antibiotic treatment. We hypothesize that the three regulons are an important part of the bacterium's response to vancomycin stress.


2007 ◽  
Vol 75 (5) ◽  
pp. 2421-2431 ◽  
Author(s):  
Lori A. Bibb ◽  
Carey A. Kunkle ◽  
Michael P. Schmitt

ABSTRACT Transcription of the Corynebacterium diphtheriae hmuO gene, which encodes a heme oxygenase involved in heme iron utilization, is activated in a heme- or hemoglobin-dependent manner in part by the two-component system ChrA-ChrS. Mutation of either the chrA or the chrS gene resulted in a marked reduction of hemoglobin-dependent activation at the hmuO promoter in C. diphtheriae; however, it was observed that significant levels of hemoglobin-dependent expression were maintained in the mutants, suggesting that an additional activator is involved in regulation. A BLAST search of the C. diphtheriae genome sequence revealed a second two-component system, encoded by DIP2268 and DIP2267, that shares similarity with ChrS and ChrA, respectively; we have designated these genes hrrS (DIP2268) and hrrA (DIP2267). Analysis of hmuO promoter expression demonstrated that hemoglobin-dependent activity was fully abolished in strains from which both the chrA-chrS and the hrrA-hrrS two-component systems were deleted. Similarly, deletion of the sensor kinase genes chrS and hrrS or the genes encoding both of the response regulators chrA and hrrA also eliminated hemoglobin-dependent activation at the hmuO promoter. We also show that the regulators ChrA-ChrS and HrrA-HrrS are involved in the hemoglobin-dependent repression of the promoter upstream of hemA, which encodes a heme biosynthesis enzyme. Evidence for cross talk between the ChrA-ChrS and HrrA-HrrS systems is presented. In conclusion, these findings demonstrate that the ChrA-ChrS and HrrA-HrrS regulatory systems are critical for full hemoglobin-dependent activation at the hmuO promoter and also suggest that these two-component systems are involved in the complex mechanism of the regulation of heme homeostasis in C. diphtheriae.


2007 ◽  
Vol 190 (2) ◽  
pp. 613-624 ◽  
Author(s):  
Xingqi Shi ◽  
Sigrun Wegener-Feldbrügge ◽  
Stuart Huntley ◽  
Nils Hamann ◽  
Reiner Hedderich ◽  
...  

ABSTRACT Proteins of two-component systems (TCS) have essential functions in the sensing of external and self-generated signals in bacteria and in the generation of appropriate output responses. Accordingly, in Myxococcus xanthus, TCS are important for normal motility and fruiting body formation and sporulation. Here we analyzed the M. xanthus genome for the presence and genetic organization of genes encoding TCS. Two hundred seventy-two TCS genes were identified, 251 of which are not part of che gene clusters. We report that the TCS genes are unusually organized, with 55% being orphan and 16% in complex gene clusters whereas only 29% display the standard paired gene organization. Hybrid histidine protein kinases and histidine protein kinases predicted to be localized to the cytoplasm are overrepresented among proteins encoded by orphan genes or in complex gene clusters. Similarly, response regulators without output domains are overrepresented among proteins encoded by orphan genes or in complex gene clusters. The most frequently occurring output domains in response regulators are involved in DNA binding and cyclic-di-GMP metabolism. Our analyses suggest that TCS encoded by orphan genes and complex gene clusters are functionally distinct from TCS encoded by paired genes and that the connectivity of the pathways made up of TCS encoded by orphan genes and complex gene clusters is different from that of pathways involving TCS encoded by paired genes. Experimentally, we observed that orphan TCS genes are overrepresented among genes that display altered transcription during fruiting body formation. The systematic analysis of the 25 orphan genes encoding histidine protein kinases that are transcriptionally up-regulated during development showed that 2 such genes are likely essential for viability and identified 7 histidine protein kinases, including 4 not previously characterized that have important function in fruiting body formation or spore germination.


AoB Plants ◽  
2019 ◽  
Author(s):  
Kanika Khanna ◽  
Vijay Lakshmi Jamwal ◽  
Anket Sharma ◽  
Sumit G Gandhi ◽  
Puja Ohri ◽  
...  

Abstract Environmental stress imposes negative impacts on the growth and development of the crop plants. The present study was designed to assess the effect of PGPR (Pseudomonas aeruginosa and Burkholderia gladioli) on plant pigments and phenolic compounds in 10-days-old root knot nematode (RKN)-infected Lycopersiconesculentum seedlings. The levels of different osmoprotectants and organic acids were also evaluated in nematode-infected L. esculentum seedlings. Our results revealed that nematode-infected seedlings had reduced levels of plant pigments(chlorophyll (70.5%), carotenoids (64.8%), and xanthophylls (34.3%)) and enhanced levels of phenolic compounds(total phenols (40.3%), flavonoids (80.9%), anthocyanins (28.9%), and polyphenols (366.1%)), osmoprotectants(total osmolytes (15.3%), total carbohydrates (54.9%), reducing sugars (45.3%), trehalose (94.5%), glycine betaine (59.01%) and proline (69.6%) and (citric acid (28.4%), fumaric acid (18.16%), succinic acid (179.9%), and malic acid (21.7%)). The levels of these metabolites increased after inoculation with P. aeruginosa and B. gladioli. The expression of genes encoding different enzymes pertaining to phenols and organic acid metabolism were also studied. The expression of genes was elevated in nematode-infected plants i.e. CHS (chalcone synthase) by 1.32 folds, PAL (phenylalanine ammonia lyase) by 1.16 folds, CS (citrate synthase)1.6 folds, SUCLG1 (succinyl Co-A ligase) by 1.19 folds, SDH (succinate dehydrogenase) by 1.92 folds, FH (fumarate hydratase) by 2.4 foldsand malate synthase (MS) by 1.26 folds and further upregulated after PGPR inoculation. This study demonstrates the importance of PGPR in managing nematode infection in plants through alteration in the synthesis of different secondary metabolites in plants.


2021 ◽  
Vol 9 (3) ◽  
pp. 485
Author(s):  
Ke Fan ◽  
Qiao Cao ◽  
Lefu Lan

BfmR is a response regulator that modulates diverse pathogenic phenotypes and induces an acute-to-chronic virulence switch in Pseudomonas aeruginosa, an important human pathogen causing serious nosocomial infections. However, the mechanisms of action of BfmR remain largely unknown. Here, using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), we showed that 174 chromosomal regions of P. aeruginosa MPAO1 genome were highly enriched by coimmunoprecipitation with a C-terminal Flag-tagged BfmR. Integration of these data with global transcriptome analyses revealed that 172 genes in 106 predicted transcription units are potential targets for BfmR. We determined that BfmR binds to and modulates the promoter activity of genes encoding transcriptional regulators CzcR, ExsA, and PhoB. Intriguingly, BfmR bound to the promoters of a number of genes belong to either CzcR or PhoB regulon, or both, indicating that CzcRS and PhoBR two-component systems (TCSs) deeply feed into the BfmR-mediated regulatory network. In addition, we demonstrated that phoB is required for BfmR to promote the biofilm formation by P. aeruginosa. These results delineate the direct BfmR regulon and exemplify the complexity of BfmR-mediated regulation of cellular functions in P. aeruginosa.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
F. C. Tilley ◽  
C. Arrondel ◽  
C. Chhuon ◽  
M. Boisson ◽  
N. Cagnard ◽  
...  

AbstractSeveral studies have reported WDR73 mutations to be causative of Galloway–Mowat syndrome, a rare disorder characterised by the association of neurological defects and renal-glomerular disease. In this study, we demonstrate interaction of WDR73 with the INTS9 and INTS11 components of Integrator, a large multiprotein complex with various roles in RNA metabolism and transcriptional control. We implicate WDR73 in two Integrator-regulated cellular pathways; namely, the processing of uridylate-rich small nuclear RNAs (UsnRNA), and mediating the transcriptional response to epidermal growth factor stimulation. We also show that WDR73 suppression leads to altered expression of genes encoding cell cycle regulatory proteins. Altogether, our results suggest that a range of cellular pathways are perturbed by WDR73 loss-of-function, and support the consensus that proper regulation of UsnRNA maturation, transcription initiation and cell cycle control are all critical in maintaining the health of post-mitotic cells such as glomerular podocytes and neurons, and preventing degenerative disease.


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