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Bacteria AND essential genes

Rodrigo Ochoa, María Cecilia Martínez-Pabón, María Adelaida Arismendi-Echeverri, Willer Leandro Rendón-Osorio, Carlos Enrique Muskus-López
Biofilm is an extremely complex microbial community arranged in a matrix of polysaccharides and attached to a substrate. Its development is crucial in the pathophysiology of oral infections like dental caries, as well as in periodontal, pulp, and periapical diseases. Streptococcus mutans is one of the most effective microorganisms in lactic acid production of the dental biofilm. Identifying essential Streptococcus mutans proteins using bioinformatics methods helps to search for alternative therapies. To this end, the bacterial genomes of several Streptococcus mutans strains and representative strains of other cariogenic and non-cariogenic bacteria were analysed by identifying pathogenicity islands and alignments with other bacteria, and by detecting the exclusive genes of cariogenic species in comparison to the non-pathogenic ones...
July 1, 2017: Archives of Oral Biology
Lorena Ruiz, Francesca Bottacini, Christine J Boinett, Amy K Cain, Mary O'Connell-Motherway, Trevor D Lawley, Douwe van Sinderen
Bifidobacteria are common gut commensals with purported health-promoting effects. This has encouraged scientific research into bifidobacteria, though recalcitrance to genetic manipulation and scarcity of molecular tools has hampered our knowledge on the precise molecular determinants of their health-promoting attributes and gut adaptation. To overcome this problem and facilitate functional genomic analyses in bifidobacteria, we created a large Tn5 transposon mutant library of the commensal Bifidobacterium breve UCC2003 that was further characterized by means of a Transposon Directed Insertion Sequencing (TraDIS) approach...
July 17, 2017: Scientific Reports
Jiazhang Qiu, Zhao-Qing Luo
Legionella pneumophila and Coxiella burnetii are two evolutionarily related intracellular pathogens that use the Dot/Icm type IV secretion system to translocate effectors into host cells. These effectors are essential for the establishment of membrane-bound compartments known as replication vacuoles, which enable the survival and replication of bacteria inside host cells. The effectors interfere with diverse signalling pathways to co-opt host processes, such as vesicle trafficking, ubiquitylation, gene expression and lipid metabolism, to promote pathogen survival...
July 17, 2017: Nature Reviews. Microbiology
Pegah Shakib, Rashid Ramazan Zadeh, Morovat Taherikalani, Bijan Nouri
BACKGROUND: Production of Beta-Lactamase enzymes, especially extended-spectrum Beta -Lactamases (ESBL), is a primary mechanism of resistance in these bacteria. The purpose of this study was detection of blaTEM, blaSHV, blaCTX-M, blaCTX-M-15, blaPER and blaVEB in K. pneumoniae, isolated from clinical specimens by the PCR method and antibiotic susceptibility patterns in these strains isolated, in Sanandaj city, Iran. MATERIALS AND METHODS: During a period from October 2015 to July 2016, 52 K...
July 13, 2017: Infectious Disorders Drug Targets
Aihua Hou, Min Qi Tin, Louis Tong
BACKGROUND: Gram-positive bacteria stimulate Toll-like receptor (TLR) 2 and then activate the pro-inflammatory nuclear factor-kappa B (NF-κB) pathway. As the human ocular surface is heavily colonised by gram-positive cocci bacteria, a balance of activation/repression of NF-κB target genes is essential to avoid uncontrolled infection or autoimmune-related inflammation. It is advantageous to test NF-κB targeting molecules in an ocular surface culture system that allows assessment of temporal NF-κB activation in a longitudinal fashion without destruction of cells...
2017: Eye and Vision (London, England)
Gordon M Bennett, Rebecca A Chong
The agricultural pest the Glassy-winged sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae: GWSS), harbors two bacterial symbionts, "Candidatus Sulcia muelleri" and "Ca Baumannia cicadellinicola", that provide the ten essential amino acids (EAAs) limited in the host plant-sap diet. Although differing in origins and symbiotic age, both bacteria have experienced extensive genome degradation resulting from their ancient restriction to specialized host organs (bacteriomes) that provide cellular support and ensure vertical transmission...
July 13, 2017: G3: Genes—Genomes—Genetics
Nina Germic, Darko Stojkov, Kevin Oberson, Shida Yousefi, Hans-Uwe Simon
The importance of extracellular traps (ETs) in innate immunity is well established, but the molecular mechanisms responsible for their formation remain unclear and in scientific dispute. ETs have been defined as extracellular DNA scaffolds associated with the granule proteins of eosinophils or neutrophils. They are capable of killing bacteria extracellularly. Based mainly on results with phosphoinositide 3-kinase (PI3K) inhibitors such as 3-methyladenine (3-MA) and wortmannin which are commonly used to inhibit autophagy, several groups have reported that autophagy is required for neutrophil extracellular trap (NET) formation...
July 13, 2017: Immunology
Changyong Cheng, Zhimei Dong, Xiao Han, Hang Wang, Li Jiang, Jing Sun, Yongchun Yang, Tiantian Ma, Chunyan Shao, Xiaodu Wang, Zhongwei Chen, Weihuan Fang, Nancy E Freitag, Huarong Huang, Houhui Song
Microbes employ the thioredoxin system to defend against oxidative stress and ensure correct disulfide bonding to maintain protein function. Listeria monocytogenes has been shown to encode a putative thioredoxin, TrxA, but its biological roles and underlying mechanisms remain unknown. Here, we showed that expression of L. monocytogenes TrxA is significantly induced in bacteria treated with the thiol-specific oxidizing agent, diamide. Deletion of trxA markedly compromised tolerance of the pathogen to diamide, and mainly impaired early stages of infection in human intestinal epithelial Caco-2 cells...
2017: Frontiers in Cellular and Infection Microbiology
Nicolle F Som, Daniel Heine, Neil A Holmes, John T Munnoch, Govind Chandra, Ryan F Seipke, Paul A Hoskisson, Barrie Wilkinson, Matthew I Hutchings
Streptomyces bacteria make numerous secondary metabolites, including half of all known antibiotics. Production of antibiotics is usually coordinated with the onset of sporulation but the cross regulation of these processes is not fully understood. This is important because most Streptomyces antibiotics are produced at low levels or not at all under laboratory conditions and this makes large scale production of these compounds very challenging. Here, we characterize the highly conserved actinobacterial two-component system MtrAB in the model organism Streptomyces venezuelae and provide evidence that it coordinates production of the antibiotic chloramphenicol with sporulation...
2017: Frontiers in Microbiology
Hironori Taniguchi, Tobias Busche, Thomas Patschkowski, Karsten Niehaus, Miroslav Pátek, Jörn Kalinowski, Volker F Wendisch
BACKGROUND: Sigma factors are one of the components of RNA polymerase holoenzymes, and an essential factor of transcription initiation in bacteria. Corynebacterium glutamicum possesses seven genes coding for sigma factors, most of which have been studied to some detail; however, the role of SigD in transcriptional regulation in C. glutamicum has been mostly unknown. RESULTS: In this work, pleiotropic effects of sigD overexpression at the level of phenotype, transcripts, proteins and metabolites were investigated...
July 12, 2017: BMC Microbiology
Kristie Stauch-White, Varun N Srinivasan, W Camilla Kuo-Dahab, Chul Park, Caitlyn S Butler
Recently, the use of phototrophs for wastewater treatment has been revisited because of new approaches to separate them from effluent streams. One manifestation uses oxygenic photogranules (OPGs) which are dense, easily-settleable granular biofilms of cyanobacteria, which surrounding populations of heterotrophs, autotrophs, and microalgae. OPGs can remove COD and nitrogenous compounds without external aeration. To better grow and maintain biomass in the proposed wastewater process, this study seeks to understand the factors that contribute to successful granulation...
December 2017: AMB Express
Zhongshan Wang, Meng Zhang, Xiaodong Shi, Quanju Xiang
The coding sequence of Salmonella enterica gsiA was cloned and expressed in E. coli. The protein was purified and ATPase activity was characterized by NADH oxidation method. GsiA exhibited optimum activity at 30°C and at pH 8 in Tris/HCl buffer. GsiA protein was stable at 20°C. 66% and 44% activity remained after incubation at 30°C and 40°C for 30 min. pH 7 and pH 9 incubation would obviously reduce the ATPase activity. In vivo functionality of gsiA was determined by constructing gene deletion strains...
2017: BioMed Research International
Michael A Funk, Wilfred A van der Donk
Ribosomally synthesized and Post-translationally modified Peptides (RiPPs) take advantage of the ribosomal translation machinery to generate linear peptides that are subsequently modified with heterocycles and/or macrocycles to impose three-dimensional structure and thwart degradation by proteases. Although RiPP precursors are limited to proteinogenic amino acids, post-translational modifications (PTMs) can alter the structure of individual amino acids and thereby improve the stability and biological activity of the molecule...
July 6, 2017: Accounts of Chemical Research
Eloy Caballo-Ponce, Jesús Murillo, Marta Martínez-Gil, Alba Moreno-Pérez, Adrián Pintado, Cayo Ramos
The study of the molecular basis of tree diseases is lately receiving a renewed attention, especially with the emerging perception that pathogens require specific pathogenicity and virulence factors to successfully colonize woody hosts. Pathosystems involving woody plants are notoriously difficult to study, although the use of model bacterial strains together with genetically homogeneous micropropagated plant material is providing a significant impetus to our understanding of the molecular determinants leading to disease...
2017: Frontiers in Plant Science
Issei Nishimura, Masaomi Kurokawa, Liu Liu, Bei-Wen Ying
Genome size is determined during evolution, but it can also be altered by genetic engineering in laboratories. The systematic characterization of reduced genomes provides valuable insights into the cellular properties that are quantitatively described by the global parameters related to the dynamics of growth and mutation. In the present study, we analyzed a small collection of W3110 Escherichia coli derivatives containing either the wild-type genome or reduced genomes of various lengths to examine whether the mutation rate, a global parameter representing genomic plasticity, was affected by genome reduction...
July 5, 2017: MBio
Astrid Bryon, Andre H Kurlovs, Wannes Dermauw, Robert Greenhalgh, Maria Riga, Miodrag Grbić, Luc Tirry, Masahiro Osakabe, John Vontas, Richard M Clark, Thomas Van Leeuwen
Carotenoids underlie many of the vibrant yellow, orange, and red colors in animals, and are involved in processes ranging from vision to protection from stresses. Most animals acquire carotenoids from their diets because de novo synthesis of carotenoids is primarily limited to plants and some bacteria and fungi. Recently, sequencing projects in aphids and adelgids, spider mites, and gall midges identified genes with homology to fungal sequences encoding de novo carotenoid biosynthetic proteins like phytoene desaturase...
Khalid Ali Khan, Mohammad Javed Ansari, Ahmad Al-Ghamdi, Adgaba Nuru, Steve Harakeh, Javaid Iqbal
The microbial communities associated with the alimentary tract of honey bees are very important as they help with food digestion, provide essential nutrients, protect the host from pathogens, detoxify harmful molecules, and increase host immunity. In this study, the structural diversity of the gut microbial communities of native honey bees, Apis mellifera jemenitica from two different geographical regions (Riyadh and Al-Baha) of Saudi Arabia was analyzed by culture-dependent methods and 16S ribosomal RNA (rRNA) gene sequencing...
July 2017: Saudi Journal of Biological Sciences
Anthony J Michael
Since the emergence of the last common ancestor from which all extant life evolved, the metabolite repertoire of cells has increased and diversified. Not only has the metabolite cosmos expanded, but the ways in which the same metabolites are made have diversified. Enzymes catalyzing the same reaction have evolved independently from different protein folds; the same protein fold can produce enzymes recognizing different substrates, and enzymes performing different chemistries. Genes encoding useful enzymes can be transferred between organisms and even between the major domains of life...
June 27, 2017: Biochemical Journal
Merle Hirschmann, Florian Grundmann, Helge B Bode
Effective iron acquisition and fine-tuned intracellular iron storage systems are the main prerequisites for a successful host invasion by a pathogen. Bacteria have developed several different strategies to sequester this essential element from their environment, one relies on the secretion of low molecular weight compounds with high affinity for ferric iron, the so-called siderophores. Here we report hydroxamate siderophore structures produced by entomopathogenic bacteria of the species Xenorhabdus and Photorhabdus, which are known for their potential to produce bioactive natural products, required for their role as nematode symbiont and insect pathogen...
June 27, 2017: Environmental Microbiology
Erik Ladomersky, Aslam Khan, Vinit Shanbhag, Jennifer S Cavet, Jefferson Chan, Gary A Weisman, Michael J Petris
Copper is an essential, yet potentially toxic trace element that is required by all aerobic organisms. A key regulator of copper homeostasis in mammalian cells is the copper transporting P-type ATPase, ATP7A, which mediates copper transport from the cytoplasm into the secretory pathway, as well as copper export across the plasma membrane. Previous studies have shown that ATP7A-dependent copper transport is required for killing phagocytosed Escherichia coli in a cultured macrophage cell line. Herein, we expand on these studies by generating Atp7a(LysMcre) mice in which the Atp7a gene was specifically deleted in cells of the myeloid lineage including macrophages...
June 26, 2017: Infection and Immunity
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