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Bacterial genomics

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https://www.readbyqxmd.com/read/28634692/crispr-cas-orthologues-and-variants-optimizing-the-repertoire-specificity-and-delivery-of-genome-engineering-tools
#1
Alberto Cebrian-Serrano, Benjamin Davies
Robust and cost-effective genome editing in a diverse array of cells and model organisms is now possible thanks to the discovery of the RNA-guided endonucleases of the CRISPR-Cas system. The commonly used Cas9 of Streptococcus pyogenes shows high levels of activity but, depending on the application, has been associated with some shortcomings. Firstly, the enzyme has been shown to cause mutagenesis at genomic sequences resembling the target sequence. Secondly, the stringent requirement for a specific motif adjacent to the selected target site can limit the target range of this enzyme...
June 20, 2017: Mammalian Genome: Official Journal of the International Mammalian Genome Society
https://www.readbyqxmd.com/read/28634470/the-dark-side-of-the-mushroom-spring-microbial-mat-life-in-the-shadow-of-chlorophototrophs-ii-metabolic-functions-of-abundant-community-members-predicted-from-metagenomic-analyses
#2
Vera Thiel, Michael Hügler, David M Ward, Donald A Bryant
Microbial mat communities in the effluent channels of Octopus and Mushroom Springs within the Lower Geyser Basin of Yellowstone National Park have been extensively characterized. Previous studies have focused on the chlorophototrophic organisms of the phyla Cyanobacteria and Chloroflexi. However, the diversity and metabolic functions of the other portion of the community in the microoxic/anoxic region of the mat are poorly understood. We recently described the diverse but extremely uneven microbial assemblage in the undermat of Mushroom Spring based on 16S rRNA amplicon sequences, which was dominated by Roseiflexus members, filamentous anoxygenic chlorophototrophs...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28633662/orthored-a-rapid-and-accurate-orthology-prediction-tool-with-low-computational-requirement
#3
Kai Battenberg, Ernest K Lee, Joanna C Chiu, Alison M Berry, Daniel Potter
BACKGROUND: Identifying orthologous genes is an initial step required for phylogenetics, and it is also a common strategy employed in functional genetics to find candidates for functionally equivalent genes across multiple species. At the same time, in silico orthology prediction tools often require large computational resources only available on computing clusters. Here we present OrthoReD, an open-source orthology prediction tool with accuracy comparable to published tools that requires only a desktop computer...
June 21, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/28633080/disruptive-non-disruptive-applications-of-crispr-cas9
#4
REVIEW
Jonathan L Schmid-Burgk
The bacterial type II Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-CRISPR Associated (Cas) systems, and in particular Streptococcus pyogenes CRISPR-Cas9, have been broadly applied to edit the genome of bacterial and eukaryotic cells. Cas9, which is an RNA-guided programmable nuclease, is a powerful tool for disrupting protein-coding genes. Cas9 cleaves target sites to generate a double-strand break (DSB) that is repaired via an error-prone repair process, leading to insertion/deletion mutations and gene knockouts...
June 17, 2017: Current Opinion in Biotechnology
https://www.readbyqxmd.com/read/28632895/genome-mining-reveals-high-incidence-of-putative-lipopeptide-biosynthesis-nrps-pks-clusters-containing-fatty-acyl-amp-ligase-genes-in-biofilm-forming-cyanobacteria
#5
Tomáš Galica, Pavel Hrouzek, Jan Mareš
Cyanobacterial lipopeptides exhibit antimicrobial and antifungal bioactivities with potential for use in pharmaceutical research. However, due to their haemolytic activity and cytotoxic effects against human cells, they may pose a health issue if produced in substantial amounts in the environment. In bacteria, lipopeptides can be synthesized via several well-evidenced mechanisms. In one of them, fatty acyl-AMP ligase (FAAL) initiates the biosynthesis by activation of a fatty acyl residue. We have performed a bioinformatic survey of the cyanobacterial genomic information available in the public databases for the presence of FAAL-containing non-ribosomal peptide synthetase/polyketide synthetase (NRPS/PKS) biosynthetic clusters, as a genetic basis for lipopeptide biosynthesis...
June 20, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28632115/flaviaesturariibacter-luteus-sp-nov-isolated-from-an-agricultural-floodplain-soil-and-emended-description-of-the-genus-flaviaesturariibacter
#6
Javier Pascual, Bärbel U Foesel, Alicia Geppert, Katharina J Huber, Jörg Overmann
A novel slow-growing bacterial strain designated as AW305T was isolated from an agricultural floodplain soil located in Mashare, Kavango region, Namibia. Cells stained Gram-negative, were non-motile, non-spore-forming, coccoid to rod-shaped and did not form a capsule. Colonies were yellow-pigmented, but flexirubin-type pigments were not detected. AW305T had an aerobic chemo-organoheterotrophic metabolism, using a narrow spectrum of carbon sources for growth, with preference for complex protein substrates, organic acids and amino acids...
June 20, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28631219/agrobacterium-tumefaciens-mediated-transformation-of-oleaginous-yeast-lipomyces-species
#7
Ziyu Dai, Shuang Deng, David E Culley, Kenneth S Bruno, Jon K Magnuson
Interest in using renewable sources of carbon, especially lignocellulosic biomass, for the production of hydrocarbon fuels and chemicals has fueled interest in exploring various organisms capable of producing hydrocarbon biofuels and chemicals or their precursors. The oleaginous (oil-producing) yeast Lipomyces starkeyi is the subject of active research regarding the production of triacylglycerides as hydrocarbon fuel precursors using a variety of carbohydrate and nutrient sources. The genome of L. starkeyi has been published, which opens the door to production strain improvements through the development and use of the tools of synthetic biology for this oleaginous species...
June 19, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28630127/deciphering-function-of-new-gonococcal-vaccine-antigens-using-phenotypic-microarrays
#8
Benjamin I Baarda, Sarah Emerson, Philip J Proteau, Aleksandra E Sikora
The function and extracellular location of cell envelope proteins make them attractive candidates for developing vaccines against bacterial diseases, including challenging, drug-resistant pathogens such as Neisseria gonorrhoeae Proteomics-driven reverse vaccinology delivered multiple gonorrhea vaccine candidates; however, the biological functions of many of them remain to be elucidated. Herein, the functions of six gonorrhea vaccine candidates - NGO2121, NGO1985, NGO2054, NGO2111, NGO1205, and NGO1344 - in cell envelope homeostasis were probed using phenotype microarrays with 1,056 conditions and a ΔbamE mutant (Δngo1780) as a reference of perturbed outer membrane integrity...
June 19, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28630115/discovering-complete-quasispecies-in-bacterial-genomes
#9
Frederic Bertels, Chaitanya S Gokhale, Arne Traulsen
Mobile genetic elements can be found in almost all genomes. Possibly the most common non-autonomous mobile genetic elements in bacteria are REPINs that can occur hundreds of times within a genome. The sum of all REPINs in a genome can be viewed as an evolving population because REPINs replicate and mutate. In contrast to most other biological populations, we know the exact composition of the REPIN population and the sequence of each member of the population. Here, we model the evolution of REPINs as quasispecies...
June 19, 2017: Genetics
https://www.readbyqxmd.com/read/28629507/oceanisphaera-marina-sp-nov-isolated-from-a-deep-sea-seamount
#10
Jie Liu, Ya-Wen Sun, Dan-Dan Zhang, Sheng-Nan Li, De-Chao Zhang
A Gram-stain-negative, rod-shaped, strictly aerobic, motile bacterial strain, designated YM319T, was isolated from a seamount near the Yap Trench in the tropical western Pacific. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain YM319T was related to the genus Oceanisphaera and had highest 16S rRNA gene sequence similarities with the type strains Oceanisphaera profunda SM1222T (97.4 %), Oceanisphaera sediminis TW92T (97.3 %) and Oceanisphaera ostreae T-w6T (97.1 %). The predominant cellular fatty acids were summed feature 3 (composed of iso-C15 : 0 2-OH and/or C16 : 1 ω7c), C16 : 0 and C18 : 1ω7c...
June 20, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28629503/red-pink-pigmented-hymenobacter-coccineus-sp-nov-hymenobacter-lapidarius-sp-nov-and-hymenobacter-glacialis-sp-nov-isolated-from-rocks-in-antarctica
#11
Ivo Sedláček, Stanislava Králová, Kamila Kýrová, Ivana Mašlaňová, Hans-Jürgen Busse, Eva Staňková, Veronika Vrbovská, Miroslav Němec, Miloš Barták, Pavla Holochová, Pavel Švec, Roman Pantůček
Four rod-shaped and Gram-stain-negative bacterial strains, CCM 8647, CCM 8649T, CCM 8643T and CCM 8648T, were isolated from rock samples collected on James Ross Island, Antarctica. Extensive biotyping, fatty acid profiling, chemotaxonomy, 16S rRNA gene sequencing and whole-genome sequencing was applied to isolates to clarify their taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that all four isolates belonged to the genus Hymenobacter. Strains CCM 8649T and CCM 8647 were most closely related to Hymenobacter arizonensis OR362-8T (94...
June 20, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28629495/noviherbaspirillum-denitrificans-sp-nov-a-denitrifying-bacterium-isolated-from-rice-paddy-soil-and-noviherbaspirillum-autotrophicum-sp-nov-a-denitrifying-facultatively-autotrophic-bacterium-isolated-from-rice-paddy-soil-and-proposal-to-reclassify-herbaspirillum
#12
Satoshi Ishii, Naoaki Ashida, Hiroki Ohno, Takahiro Segawa, Shuhei Yabe, Shigeto Otsuka, Akira Yokota, Keishi Senoo
Thirty-nine denitrifying bacterial strains closely related to one another, represented by strains TSA40T and TSA66T, were isolated from rice paddy soils. Strains TSA40T and TSA66T were Gram-stain-negative, slightly curved rod-shaped, and motile by means of polar flagella. They were able to reduce nitrate, nitrite and nitrous oxide, but unable to fix atmospheric N2. While strain TSA66T was able to grow autotrophically by H2-dependent denitrification, strain TSA40T could not. Phylogenetic analysis suggested that they belong to the family Oxalobacteraceae, the order Burkholderiales in the class Betaproteobacteria...
June 20, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28629206/an-enhanced-vector-free-allele-exchange-vfae-mutagenesis-protocol-for-genome-editing-in-a-wide-range-of-bacterial-species
#13
Ahmed E Gomaa, Chen Zhang, Zhimin Yang, Liguo Shang, Shijie Jiang, Zhiping Deng, Yuhua Zhan, Wei Lu, Min Lin, Yongliang Yan
Vector-free allele exchange (VFAE) is a newly developed protocol for genome editing in Pseudomonas species. Although several parameters have been determined to optimize the procedures for obtaining a stable and high-frequency mutation, numerous false-positive clones still appear on the plate, which increases the difficulty of finding the desired mutants. It has also not been established whether this protocol can be used for genome editing in other bacterial species. In the current study, the protocol was modified to dramatically decrease the occurrence of false-positive colonies using Pseudomonas stutzeri A1501 as a model strain...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28628637/survival-bacterial-clearance-and-thrombocytopenia-are-improved-in-polymicrobial-sepsis-by-targeting-nuclear-transport-shuttles
#14
Ruth Ann Veach, Yan Liu, Jozef Zienkiewicz, Lukasz S Wylezinski, Kelli L Boyd, James L Wynn, Jacek Hawiger
The rising tide of sepsis, a leading cause of death in the US and globally, is not adequately controlled by current antimicrobial therapies and supportive measures, thereby requiring new adjunctive treatments. Severe microvascular injury and multiple organ failure in sepsis are attributed to a "genomic storm" resulting from changes in microbial and host genomes encoding virulence factors and endogenous inflammatory mediators, respectively. This storm is mediated by stress-responsive transcription factors that are ferried to the nucleus by nuclear transport shuttles importins/karyopherins...
2017: PloS One
https://www.readbyqxmd.com/read/28625995/novel-antibiotic-resistance-determinants-from-agricultural-soil-exposed-to-antibiotics-widely-used-in-human-medicine-and-animal-farming
#15
Calvin Ho-Fung Lau, Kalene van Engelen, Stephen Gordon, Justin Renaud, Edward Topp
Antibiotic resistance has emerged globally as one of the biggest threats to human and animal health. Although the excessive use of antibiotics is recognized for accelerating the selection for resistance, there is a growing body of evidence suggesting that natural environments are "hotspots" for the development of both ancient and contemporary resistance mechanisms. Given that pharmaceuticals can be entrained onto agricultural land through anthropogenic activities, this could be a potential driver for the emergence and dissemination of resistance in soil bacteria...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28624614/gene-transfer-agent-promotes-evolvability-within-the-fittest-subpopulation-of-a-bacterial-pathogen
#16
Maxime Québatte, Matthias Christen, Alexander Harms, Jonas Körner, Beat Christen, Christoph Dehio
The Bartonella gene transfer agent (BaGTA) is an archetypical example for domestication of a phage-derived element to permit high-frequency genetic exchange in bacterial populations. Here we used multiplexed transposon sequencing (TnSeq) and single-cell reporters to globally define the core components and transfer dynamics of BaGTA. Our systems-level analysis has identified inner- and outer-circle components of the BaGTA system, including 55 regulatory components, as well as an additional 74 and 107 components mediating donor transfer and recipient uptake functions...
June 14, 2017: Cell Systems
https://www.readbyqxmd.com/read/28624550/comparative-genome-analysis-of-fish-pathogen-flavobacterium-columnare-reveals-extensive-sequence-diversity-within-the-species
#17
Pattanapon Kayansamruaj, Ha Thanh Dong, Ikuo Hirono, Hidehiro Kondo, Saengchan Senapin, Channarong Rodkhum
Flavobacterium columnare is one of the deadliest fish pathogens causing devastating mortality in various freshwater fish species globally. To gain an insight into bacterial genomic contents and structures, comparative genome analyses were performed using the reference and newly sequenced genomes of F. columnare including genomovar I, II and I/II strains isolated from Thailand, Europe and the USA. Bacterial genomes varied in size from 3.09 to 3.39Mb (2714 to 3101 CDSs). The pan-genome analysis revealed open pan-genome nature of F...
June 14, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28623391/survey-of-high-affinity-h2-oxidizing-bacteria-in-soil-reveals-their-vast-diversity-yet-underrepresentation-in-genomic-databases
#18
Sarah Piché-Choquette, Mondher Khdhiri, Philippe Constant
While high-affinity H2-oxidizing bacteria (HA-HOB) serve as the main sink of atmospheric H2, the ecology of this specialist functional group is rather unknown due to its recent discovery. The main purpose of our study is to provide the first extensive survey of HA-HOB in farmland, larch, and poplar soils exposed to 0.5 and 10,000 ppmv H2. Using qPCR and qRT-PCR assays along with PCR amplicon high-throughput sequencing of hhyL gene encoding for the large subunit of high-affinity [NiFe]-hydrogenases (HAH), we found that hhyL gene expression ratio explained better variation in measured H2 oxidation rates than HA-HOB species richness...
June 17, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28622857/streptococcus-suis-serotype-9-strain-gz0565-contains-a-type-vii-secretion-system-putative-substrate-esxa-that-contributes-to-bacterial-virulence-and-a-vanz-like-gene-that-confers-resistance-to-teicoplanin-and-dalbavancin-in-streptococcus-agalactiae
#19
Liying Lai, Jiao Dai, Huanyu Tang, Shouming Zhang, Chunyan Wu, Wancen Qiu, Chengping Lu, Huochun Yao, Hongjie Fan, Zongfu Wu
Streptococcus suis (SS), an important pathogen for pigs, is not only considered as a zoonotic agent for humans, but is also recognized as a major reservoir of antimicrobial resistance contributing to the spread of resistance genes to other pathogenic Streptococcus species. In addition to serotype 2 (SS2), serotype 9 (SS9) is another prevalent serotype isolated from diseased pigs. Although many SS strains have been sequenced, the complete genome of a non-SS2 virulent strain has been unavailable to date. Here, we report the complete genome of GZ0565, a virulent strain of SS9, isolated from a pig with meningitis...
June 2017: Veterinary Microbiology
https://www.readbyqxmd.com/read/28620370/environmental-t4-family-bacteriophages-evolve-to-escape-abortive-infection-via-multiple-routes-in-a-bacterial-host-employing-altruistic-suicide-through-type-iii-toxin-antitoxin-systems
#20
Bihe Chen, Chidiebere Akusobi, Xinzhe Fang, George P C Salmond
Abortive infection is an anti-phage mechanism employed by a bacterium to initiate its own death upon phage infection. This reduces, or eliminates, production of viral progeny and protects clonal siblings in the bacterial population by an act akin to an "altruistic suicide." Abortive infection can be mediated by a Type III toxin-antitoxin system called ToxINPa consisting of an endoribonuclease toxin and RNA antitoxin. ToxINPa is a heterohexameric quaternary complex in which pseudoknotted RNA inhibits the toxicity of the toxin until infection by certain phages causes destabilization of ToxINPa, leading to bacteriostasis and, eventually, lethality...
2017: Frontiers in Microbiology
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