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Bacteria AND essential genes

Maarten G K Ghequire, Toon Swings, Jan Michiels, Susan K Buchanan, René De Mot
Lectin-like bacteriocins (LlpAs) are secreted by proteobacteria and selectively kill strains of their own or related species, and they are composed of two B-lectin domains with divergent sequences. In Pseudomonas spp., initial binding of these antibacterial proteins to cells is mediated by the carboxy-terminal domain through d-rhamnose residues present in the common polysaccharide antigen of their lipopolysaccharide, whereas the amino-terminal domain accounts for strain selectivity of killing. Here, we show that spontaneous LlpA-resistant mutants carry mutations in one of three surface-exposed moieties of the essential β-barrel outer membrane protein insertase BamA, the core component of the BAM complex...
March 20, 2018: MBio
Vikas C Ghattargi, Yogesh S Nimonkar, Shaunak A Burse, Dimple Davray, Shreyas V Kumbhare, Sudarshan A Shetty, Meghana A Gaikwad, Mangesh V Suryavanshi, Swapnil P Doijad, Bhimashankar Utage, Om Prakash Sharma, Yogesh S Shouche, Bharati S Meti, Shrikant P Pawar
The human gut microbiome plays a crucial role in human health and efforts need to be done for cultivation and characterisation of bacteria with potential health benefits. Here, we isolated a bacterium from a healthy Indian adult faeces and investigated its potential as probiotic. The cultured bacterial strain 17OM39 was identified as Enterococcus faecium by 16S rRNA gene sequencing. The strain 17OM39 exhibited tolerance to acidic pH, showed antimicrobial activity and displayed strong cell surface traits such as hydrophobicity and autoaggregation capacity...
March 19, 2018: Functional & Integrative Genomics
Keunsub Lee, Kan Wang
During the last decade, small noncoding RNAs (ncRNAs) have emerged as essential post-transcriptional regulators in bacteria. Nearly all important physiological and stress responses are modulated by ncRNA regulators, such as riboswitches, trans-acting small RNAs (sRNAs), and cis-antisense RNAs. Recently, three RNA-seq studies identified a total of 1534 candidate ncRNAs from Agrobacterium tumefaciens, a pathogen and biotechnology tool for plants. Only a few ncRNAs have been functionally characterized in A. tumefaciens, and some of them appear to be involved in virulence...
March 20, 2018: Current Topics in Microbiology and Immunology
Alexandre Luscher, Lucile Moynié, Pamela Saint Auguste, Dirk Bumann, Lena Mazza, Daniel Pletzer, James H Naismith, Thilo Köhler
The conjugation of siderophores to antimicrobial molecules is an attractive strategy to overcome the low outer membrane permeability of Gram-negative bacteria. In this Trojan horse approach the transport of drug conjugates is redirected via TonB-dependent receptors (TBDR), involved in the uptake of essential nutrients including iron. Previous reports have demonstrated the involvement of the TBDRs PiuA and PirA from Pseudomonas aeruginosa and their orthologues in Acinetobacter baumannii in the uptake of siderophore-beta-lactam drug conjugates...
March 19, 2018: Antimicrobial Agents and Chemotherapy
Hassan Etesami, Dinesh K Maheshwari
Increased incidence of abiotic stresses impacting adversely plant growth and productivity in major crops is being witnessed all over the world. Therefore, as a result of such stress factors, plant growth under the stress conditions will be less than the non-stress conditions. Growing concerns and global demand for correct, environmentally-friendly techniques exist to reduce the adverse effects of plant stress. Under such stressful conditions, the role of interactions of plant and beneficial microorganisms is of great significance...
March 16, 2018: Ecotoxicology and Environmental Safety
Dandan Han, Lanying Wang, Yanping Luo
Actinomycetes are an important group of gram-positive bacteria that play an essential role in the rhizosphere ecosystem. The confrontation culture and Oxford cup method were used to evaluate the antagonistic activities of strains, which were isolated from the rhizosphere soil of Mikania micrantha. The two isolates were identified using morphological and physiological tests combined with 16S rRNA-based molecular analysis, respectively. The type I polyketone synthase (PKS-I) was amplified. The constituents of fermentation metabolites were analyzed by gas chromatography mass spectrometry...
March 2018: Microbiological Research
Kavita Kadian, Sonam Vijay, Yash Gupta, Ritu Rawal, Jagbir Singh, Anup Anvikar, Veena Pande, Arun Sharma
Malaria parasites utilize Methylerythritol phosphate (MEP) pathway for synthesis of isoprenoid precursors which are essential for maturation and survival of parasites during erythrocytic and gametocytic stages. The absence of MEP pathway in the human host establishes MEP pathway enzymes as a repertoire of essential drug targets. The fourth enzyme, 4-diphosphocytidyl-2C-methyl-d-erythritol kinase (IspE) has been proved essential in pathogenic bacteria, however; it has not yet been studied in any Plasmodium species...
March 14, 2018: Parasitology International
Christian Greunke, Elke Regina Duell, Paul Michael D'Agostino, Anna Glöckle, Katharina Lamm, Tobias Alexander Marius Gulder
Specialized metabolites from bacteria are an important source of inspiration for drug development. The genes required for the biosynthesis of such metabolites in bacteria are usually organized in so-called biosynthetic gene clusters (BGCs). Using modern bioinformatic tools, the wealth of genomic data can be scanned for such BGCs and the expected products can often structurally be predicted in silico. This facilitates the directed discovery of putatively novel bacterial metabolites. However, the production of these molecules often requires genetic manipulation of the BGC for activation or the expression of the pathway in a heterologous host...
March 13, 2018: Metabolic Engineering
Dávid Szamosvári, Sina Rütschlin, Thomas Böttcher
Bacteria engage in numerous collaborative and competitive interactions, which are often mediated by small molecule metabolites. Bacterial competition involves for example the production of compounds that effectively kill or inhibit growth of their neighbours but also the secretion of siderophores that allow securing the essential and fiercely embattled resource of ferric iron. Yet, the enormous diversity of metabolites produced has remained puzzling in many cases. We here present examples of both types of competition from our recent work...
March 15, 2018: Organic & Biomolecular Chemistry
Dilruba Sharmin, Yong Guo, Tomoyasu Nishizawa, Shoko Ohshima, Yoshinori Sato, Yusuke Takashima, Kazuhiko Narisawa, Hiroyuki Ohta
Endohyphal bacteria (EHB), dwelling within fungal hyphae, markedly affect the growth and metabolic potential of their hosts. To date, two EHB belonging to the family Burkholderiaceae have been isolated and characterized as new taxa, Burkholderia rhizoxinica (HKI 454T ) and Mycoavidus cysteinexigens (B1-EBT ), in Japan. Metagenome sequencing was recently reported for Mortierella elongata AG77 together with its endosymbiont M. cysteinexigens (Mc-AG77) from a soil/litter sample in the USA. In the present study, we elucidated the complete genome sequence of B1-EBT and compared it with those of Mc-AG77 and HKI 454T ...
March 14, 2018: Microbes and Environments
Vatika Gupta, Kanika Jain, Rajni Garg, Anshu Malik, Pooja Gulati, Rakesh Bhatnagar
Microbial colonization is an outcome of appropriate sensing and regulation of its gene expression. Bacillus anthracis adapts and thrives in its environment through complex regulatory mechanisms, among them, the two component systems (TCS). Many bacteria respond to the oxygen fluctuations via TCS. In the present work, a previously uncharacterized TCS, Bas1213-1214, of B. anthracis with a probable role in oxygen sensing has been characterized as a functional TCS. A substantial increase in the expression of Bas1213 was observed during the stationary growth phase, in presence of bicarbonate ions, and under oxidative stress thereby speculating the role of Bas1213 in toxin production and adaptive responses...
March 14, 2018: Journal of Cellular Biochemistry
Raphaël Méheust, Debashish Bhattacharya, Jananan S Pathmanathan, James O McInerney, Philippe Lopez, Eric Bapteste
BACKGROUND: Eukaryotes evolved from the symbiotic association of at least two prokaryotic partners, and a good deal is known about the timings, mechanisms, and dynamics of these evolutionary steps. Recently, it was shown that a new class of nuclear genes, symbiogenetic genes (S-genes), was formed concomitant with endosymbiosis and the subsequent evolution of eukaryotic photosynthetic lineages. Understanding their origins and contributions to eukaryogenesis would provide insights into the ways in which cellular complexity has evolved...
March 13, 2018: BMC Biology
Wonsik Lee, Truc Do, Ge Zhang, Daniel Kahne, Timothy C Meredith, Suzanne Walker
Targeted modification of bacterial chromosomes is necessary to understand new drug targets, investigate virulence factors, elucidate cell physiology, and validate results of -omics-based approaches. For some bacteria, reverse genetics remains a major bottleneck to progress in research. Here we describe a compound-centric strategy that combines new negative selection markers with known positive selection markers to achieve simple, efficient one-step genome engineering of bacterial chromosomes. The method was inspired by the observation that certain non-essential metabolic pathways contain essential late steps, suggesting that antibiotics targeting a late step can be used to select for the absence of genes that control flux into the pathway...
March 13, 2018: ACS Infectious Diseases
Suchi Srivastava, Sonal Srivastava, Vidisha Bist, Surabhi Awasthi, Reshu Chauhan, Vasvi Chaudhry, Poonam C Singh, Sanjay Dwivedi, Abhishek Niranjan, Lalit Agrawal, Puneet Singh Chauhan, Rudra Deo Tripathi, Chandra Shekhar Nautiyal
Rice grown in arsenic (As) contaminated areas contributes to high dietary exposure of As inducing multiple adverse effects on human health. The As contamination and application of phosphate fertilizers during seedling stage creates a high P and As stress condition. The flooded paddy fields are also conducive for algal growth and microbial activity. The present study proposes potential role of microalgae, Chlorella vulgaris (CHL) and bacteria, Pseudomonas putida (RAR) on rice plant grown under excess As and phosphate (P) conditions...
February 23, 2018: Journal of Hazardous Materials
Daniel R Garza, Marcel C van Verk, Martijn A Huynen, Bas E Dutilh
The environmental metabolome and metabolic potential of microorganisms are dominant and essential factors shaping microbial community composition. Recent advances in genome annotation and systems biology now allow us to semiautomatically reconstruct genome-scale metabolic models (GSMMs) of microorganisms based on their genome sequence1 . Next, growth of these models in a defined metabolic environment can be predicted in silico, mechanistically linking the metabolic fluxes of individual microbial populations to the community dynamics...
March 12, 2018: Nature Microbiology
Christine M Hustmyer, Chelsea A Simpson, Stephen G Olney, Matthew L Bochman, Julia C van Kessel
Experimental studies of transcriptional regulation in bacteria require the ability to precisely measure changes in gene expression, often accomplished through the use of reporter genes. However, the boundaries of promoter sequences required for transcription are often unknown, thus complicating construction of reporters and genetic analysis of transcriptional regulation. Here, we analyze reporter libraries to define the promoter boundaries of the luxCDABE bioluminescence operon and the betIBA-proXWV osmotic stress operon in Vibrio harveyi We describe a new method called RAIL (<u>R</u>apid<u>A</u>rbitrary PCR<u>I</u>nsertion<u>L</u>ibraries) that combines the power of arbitrary PCR and isothermal DNA assembly to rapidly clone promoter fragments of various lengths upstream of reporter genes to generate large libraries...
March 12, 2018: Journal of Bacteriology
Maciej Dylewski, Monika Ćwiklińska, Katarzyna Potrykus
Small RNA are very important post-transcriptional regulators in both, bacteria and eukaryotes. One of such sRNA is GraL, encoded in the greA leader region and conserved among enteric bacteria. Here, we conducted a bioinformatics search for GraL's targets in trans and validated our findings in vivo by constructing fusions of probable targets with lacZ and measuring their activity when GraL was overexpressed. Only one target's activity (nudE) decreased under those conditions and was thus selected for further analysis...
March 12, 2018: Acta Biochimica Polonica
Sarita Pandey, Anurag Kirti, Arvind Kumar, Hema Rajaram
The ubiquitous SbcCD exonuclease complex has been shown to perform an important role in DNA repair across prokaryotes and eukaryotes. However, they have remained uncharacterized in the ancient and stress-tolerant cyanobacteria. In the cyanobacterium Anabaena sp. strain PCC7120, SbcC and SbcD homologs, defined on the basis of the presence of corresponding functional domains, are annotated as hypothetical proteins, namely Alr3988 and All4463 respectively. Unlike the presence of sbcC and sbcD genes in a bicistronic operon in most organisms, these genes were distantly placed on the chromosome in Anabaena, and found to be negatively regulated by LexA...
March 9, 2018: Functional & Integrative Genomics
Alberto Ramírez Mata, César Millán Pacheco, José F Cruz Pérez, Martha Minjárez Sáenz, Beatriz E Baca
BACKGROUND: The cyclic-di-GMP (c-di-GMP) second messenger exemplifies a signaling system that regulates many bacterial behaviors of key importance; among them, c-di-GMP controls the transition between motile and sessile life-styles in bacteria. Cellular c-di-GMP levels in bacteria are regulated by the opposite enzymatic activities of diguanylate cyclases and phosphodiesterases, which are proteins that have GGDEF and EAL domains, respectively. Azospirillum is a genus of plant-growth-promoting bacteria, and members of this genus have beneficial effects in many agronomically and ecologically essential plants...
March 9, 2018: BMC Microbiology
Jinhong Kan, Lin An, Yao Wu, Jia Long, Liyang Song, Rongxiang Fang, Yantao Jia
During plant-pathogen interactions, pathogenic bacteria have evolved multiple strategies to cope with the sophisticated defense systems of host plants. Proline iminopeptidase (PIP) is essential to Xanthomonas campestris pv. campestris (Xcc) virulence, and conserved in many plant-associated bacteria, but its pathogenic mechanism remains unclear. In this study, we found that disrupting pip in Xcc enhanced its flagella-mediated bacterial motility by decreasing intracellular c-di-GMP levels, and overexpression of pip restricted bacterial motility by elevating c-di-GMP levels...
March 8, 2018: Molecular Plant Pathology
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