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Andres Maser, Karl Peebo, Ranno Nahku
We studied Escherichia coli BW25113 growth in a complex medium with emphasis on amino acid consumption. The aim was to profile amino acid utilization in acid-hydrolysed casein and a defined nutrient-rich medium and based on these measurements modify the medium for better growth performance. Amino acid depletions in both media caused apparent biomass growth stops that prolonged growth duration. Obtained amino acid consumption values enabled a new defined medium to be formulated, where no growth stops were observed, the specific growth rate was constant, and the provided substrates were fully utilized...
November 9, 2018: Microbiology
Shota Suzuki, Naoko Kondo, Minoru Yoshida, Makoto Nishiyama, Saori Kosono
Nε -lysine acetylation and succinylation are ubiquitous post-translational modifications in eukaryotes and bacteria. In the present study, we showed a dynamic change in acetylation and succinylation of TufA, the translation elongation factor Tu, from Bacillus subtilis. Increased acetylation of TufA was observed during the exponential growth phase in LB and minimal glucose conditions, and its acetylation level decreased upon entering the stationary phase, while its succinylation increased during the late stationary phase...
November 5, 2018: Microbiology
Martín A Hernández, Héctor M Alvarez
The occurrence of NADP+ -dependent malic enzymes (NADP+ -MEs) in several Rhodococcus strains was analysed. The NADP+ -ME number in Rhodococcus genomes seemed to be a strain-dependent property. Total NADP+ -ME activity increased by 1.8- and 2.6-fold in the oleaginous Rhodococcus jostii RHA1 and Rhodococcus opacus PD630 strains during cultivation under nitrogen-limiting conditions. Total NADP+ -ME activity inhibition by sesamol resulted in a significant decrease of the cellular biomass and lipid production in oleaginous rhodococci...
October 29, 2018: Microbiology
Tomohiro Shimada, Kaneyoshi Yamamoto, Masahiro Nakano, Hiroki Watanabe, David Schleheck, Akira Ishihama
The binding sites of YihW, an uncharacterized DeoR-family transcription factor (TF) of Escherichia coli K-12, were identified using Genomic SELEX screening at two closely located sites, one inside the spacer between the bidirectional transcription units comprising the yihUTS operon and the yihV gene, and another one upstream of the yihW gene itself. Recently the YihUTS and YihV proteins were identified as catalysing the catabolism of sulfoquinovose (SQ), a hydrolysis product of sulfoquinovosyl diacylglycerol (SQDG) derived from plants and other photosynthetic organisms...
October 29, 2018: Microbiology
Junxia Liu, Kaiting Tan, Linjuan He, Yongting Qiu, Wanling Tan, Yan Guo, Zhihong Wang, Wen Sun
Eutrophication is caused by the rapid growth of microalgae. Iron and manganese are important micronutrients for microalgae growth. However, the effect of the limitation of iron and manganese on microalgae growth in fresh water has not been well understood. In this study, natural mixed algae, Anabaena flosaquae and Scenedesmus quadricanda, were cultivated under different quotas of iron and manganese to reveal the effect of the limitation of iron and manganese on the growth of microalgae in fresh water. The results showed that the growth rate of algae is influenced more by iron than by manganese...
October 26, 2018: Microbiology
Hermenegildo Taboada, Niurka Meneses, Michael F Dunn, Carmen Vargas-Lagunas, Natasha Buchs, Jaime A Castro-Mondragón, Manfred Heller, Sergio Encarnación
Rhizobium etli CE3 grown in succinate-ammonium minimal medium (MM) excreted outer membrane vesicles (OMVs) with diameters of 40 to 100 nm. Proteins from the OMVs and the periplasmic space were isolated from 6 and 24 h cultures and identified by proteome analysis. A total of 770 proteins were identified: 73.8 and 21.3 % of these occurred only in the periplasm and OMVs, respectively, and only 4.9 % were found in both locations. The majority of proteins found in either location were present only at 6 or 24 h: in the periplasm and OMVs, only 24 and 9 % of proteins, respectively, were present at both sampling times, indicating a time-dependent differential sorting of proteins into the two compartments...
October 25, 2018: Microbiology
Philip W Fowler, Ana Luíza Gibertoni Cruz, Sarah J Hoosdally, Lisa Jarrett, Emanuele Borroni, Matteo Chiacchiaretta, Priti Rathod, Sarah Lehmann, Nikolay Molodtsov, Timothy M Walker, Esther Robinson, Harald Hoffmann, Timothy E A Peto, Daniela Maria Cirillo, Grace E Smith, Derrick W Crook
M. tuberculosis grows slowly and is challenging to work with experimentally compared with many other bacteria. Although microtitre plates have the potential to enable high-throughput phenotypic testing of M. tuberculosis, they can be difficult to read and interpret. Here we present a software package, the Automated Mycobacterial Growth Detection Algorithm (AMyGDA), that measures how much M. tuberculosis is growing in each well of a 96-well microtitre plate. The plate used here has serial dilutions of 14 anti-tuberculosis drugs, thereby permitting the MICs to be elucidated...
October 23, 2018: Microbiology
Margarita Marroquin-Guzman, Juliana Krotz, Harriet Appeah, Richard A Wilson
The blast fungus Magnaporthe oryzae devastates global rice yields and is an emerging threat to wheat. Determining the metabolic strategies underlying M. oryzae growth in host cells could lead to the development of new plant protection approaches against blast. Here, we targeted asparagine synthetase (encoded by ASN1), which is required for the terminal step in asparagine production from aspartate and glutamine, the sole pathway to de novo asparagine biosynthesis in M. oryzae. Consequently, the Δasn1 mutant strains could not grow on minimal media without asparagine supplementation...
October 23, 2018: Microbiology
Lu Yu, Xindi Liu, Daniel J O'Sullivan
Bifidobacterium longum DJO10A was previously demonstrated to be able to produce a broad-spectrum lantibiotic, but production in media was very limited and only periodically on solid media. Given the difficulty of obtaining these lantibiotic peptides using B. longum DJO10A due to its tightly controlled production, genes predicted to be required for its production and immunity were designed and codon optimized according to the preferred codon used by Lactococcus lactis. Since the lanR1 gene within this lantibiotic gene cluster was the only one without a characterized analogue from other lantibiotic gene clusters, its annotation was re-examined as it was previously suggested to be a regulatory protein...
October 19, 2018: Microbiology
Joshua M Lensmire, Zachary L Pratt, Amy C L Wong, Charles W Kaspar
Salmonella enterica is a human pathogen that can produce filamentous cells in response to environmental stress. The molecular mediators and biosynthetic pathways that contribute to the formation of filamentous cells (>10 µm in length) during osmotic stress are mostly unknown. The comparison of filamentous and non-filamentous cells in this study was aided by the use of a filtration step to separate cell types. Osmotic stress caused an efflux of phosphate from cells, and the addition of phosphate and a carbohydrate to Luria broth with 7 % NaCl (LB-7NaCl) significantly increased the proportion of filamentous cells in the population (58 %)...
October 16, 2018: Microbiology
Cecilia B Di Capua, Juan M Belardinelli, María V Buchieri, Ana Bortolotti, Jorgelina J Franceschelli, Héctor R Morbidoni
Mycobacterium smegmatis is intrinsically resistant to thiacetazone, an anti-tubercular thiourea; however we report here that it causes a mild inhibition in growth in liquid medium. Since mycolic acid biosynthesis was affected, we cloned and expressed Mycobacterium smegmatis mycolic acid methyltransferases, postulated as targets for thiacetazone in other mycobacterial species. During this analysis we identified MSMEG_1350 as the methyltransferase involved in epoxy mycolic acid synthesis since its deletion led to their total loss...
October 12, 2018: Microbiology
Larissa Barelli, Camila C Moreira, Michael J Bidochka
Here we assessed the time course of rhizoplane colonization by the endophytic insect pathogenic fungus Metarhizium robertsii. We describe a method of quantifying root colonization of bean plants by M. robertsii using quantitative polymerase chain reaction (qPCR). Results of this method were compared to the standard plate count method using colony-forming units (c.f.u.). Both the c.f.u. and qPCR methods were used to monitor the time-course of haricot bean (Phaseolus vulgaris) colonization by a strain of M. robertsii that expresses the green fluorescent protein (ARSEF 2575-GFP) for colony verification...
October 12, 2018: Microbiology
Joanna L Hicks, Claire V Mullholland
The principal mechanism of reducing sulfur into organic compounds is via the synthesis of l-cysteine. Cysteine is used for protein and glutathione synthesis, as well as being the primary sulfur source for a variety of other molecules, such as biotin, coenzyme A, lipoic acid and more. Glutathione and other cysteine derivatives are important for protection against the oxidative stress that pathogenic bacteria such as Neisseria gonorrhoeae and Neisseria meningitidis encounter during infection. With the alarming rise of antibiotic-resistant strains of N...
October 11, 2018: Microbiology
Celena M Gwin, Natalia Prakash, J Christian Belisario, Lubaina Haider, Marlene L Rosen, Luis R Martinez, Nathan W Rigel
Directing the flow of protein traffic is a critical task faced by all cellular organisms. In Gram-negative bacteria, this traffic includes lipoproteins. Lipoproteins are synthesized as precursors in the cytoplasm and receive their acyl modifications upon export across the inner membrane. The third and final acyl chain is added by Lnt, which until recently was thought to be essential in all Gram-negatives. In this report, we show that Acinetobacter species can also tolerate a complete loss-of-function mutation in lnt...
October 11, 2018: Microbiology
Viviana Teresa Orlandi, Fabrizio Bolognese, Barbara Rolando, Stefano Guglielmo, Loretta Lazzarato, Roberta Fruttero
Pseudomonas aeruginosa is a microorganism that is well adapted to both clinical and industrial settings, where it can form adherent communities that are difficult to eradicate. New anti-Pseudomonas compounds and strategies are necessary, as the current antimicrobial approaches for the inhibition of biofilm formation and, above all, the eradication of formed biofilms are ineffective. Compounds that belong to the furoxan family, which are well-known NO donors, have recently been shown to display anti-Pseudomonas activity...
October 9, 2018: Microbiology
Ram P Maharjan, Thomas Ferenci
Micro-organisms often face multiple stresses in natural habitats. Individual stresses are well known to influence mutation rates and the spectra of mutational types, but the extent to which multiple stresses affect the genetic variation in populations is unknown. Here we investigate pair-wise combinations of nutritional stresses in Escherichia coli to determine their effect on mutation rates and mutational types. Environmental interactions modified both the rate and spectrum of mutations in double-limited environments, but the effects were not additive or synergistic relative to single stresses...
October 5, 2018: Microbiology
Rebecca-Ayme Hughes, Xiaohe Jin, Yunlong Zhang, Ran Zhang, Sabrina Tran, Philip G Williams, Jonathan S Lindsey, Eric S Miller
Tolyporphins are structurally diverse tetrapyrrole macrocycles produced by the cyanobacterial culture HT-58-2. Although tolyporphins were discovered over 25 years ago, little was known about the microbiology of the culture. The studies reported herein expand the description of the community of predominantly alphaproteobacteria associated with the filamentous HT-58-2 cyanobacterium and isolate a dominant bacterium, Porphyrobacter sp. HT-58-2, for which the complete genome is established and growth properties are examined...
August 17, 2018: Microbiology
Clair R Henthorn, F Chris Minion, Orhan Sahin
Mycoplasma hyopneumoniae is the causative agent of enzootic pneumonia in swine, an important disease worldwide. It has finite biosynthetic capabilities, including a deficit in de novo nucleotide synthesis. The source(s) for nucleotides in vivo are unknown, but mycoplasmas are known to carry membrane-bound nucleases thought to participate in the acquisition of nucleotides from host genomic DNA. Recent research has demonstrated that neutrophils can produce extracellular traps (NETs), chromatin NETs decorated with granular proteins to interact with and eliminate pathogens...
November 2018: Microbiology
Mark J Taylor, Seth R Bordenstein, Barton Slatko
Wolbachia is the most widespread genus of endosymbiotic bacteria in the animal world, infecting a diverse range of arthropods and nematodes. A broad spectrum of associations from parasitism to mutualism occur, with a tendency to drive reproductive manipulation or influence host fecundity to spread infection through host populations. These varied effects of Wolbachia are exploited for public health benefits. Notably, the protection of insect hosts from viruses is being tested as a potential control strategy for human arboviruses, and the mutualistic relationship with filarial nematodes makes Wolbachia a target for antibiotic therapy of human and veterinary nematode diseases...
November 2018: Microbiology
Masanobu Nishikawa, Lianhua Shen, Ken'ichi Ogawa
On the basis of previous studies on taurine assimilation in Escherichia coli, TauD, an iron- and α-ketoglutarate-dependent taurine dioxygenase, has been regarded as an indispensable factor for assimilation. However, we found that tauD-deficient strains did not lose their taurine assimilation ability when there was no deletion of ssuD, which encodes a reduced flavin mononucleotide [FMNH(2)]-dependent alkanesulfonate monooxygenase, which is responsible for the desulfonation of alkanesulfonates. There were no significant differences in lag phase time, growth rate and final growth yield between the tauD-deficient strain and the tauD wild-type strain...
November 2018: Microbiology
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