Read by QxMD icon Read

Molecular Microbiology

Matthias Gimpel, Sabine Brantl
Dual-function sRNAs are a subgroup of small regulatory RNAs that act on the one hand as base-pairing sRNAs to inhibit or activate target gene expression and on the other hand as peptide-encoding mRNAs that function either in the same or in another metabolic pathway. Here, we review and compare the five currently known and intensively characterized dual-function sRNAs with regard to their two functions, their biological role, their evolutionary conservation and their requirements for RNA chaperones. Furthermore, we summarize the data available on five potential dual-function sRNAs, whose base-pairing function is well established whereas the role of their encoded peptides has not yet been elucidated...
October 17, 2016: Molecular Microbiology
Benjamin A Webb, K Karl Compton, Rafael Castañeda Saldaña, Timofey Arapov, W Keith Ray, Richard F Helm, Birgit E Scharf
The bacterium Sinorhizobium meliloti is attracted to seed exudates of its host plant alfalfa (Medicago sativa). Since quaternary ammonium compounds (QACs) are exuded by germinating seeds, we assayed chemotaxis of S. meliloti towards betonicine, choline, glycine betaine, stachydrine, and trigonelline. The wild type displayed a positive response to all QACs. Using LC-MS, we determined that each germinating alfalfa seed exuded QACs in the nanogram range. Compared to the closely related non-host species, spotted medic (Medicago arabica), unique profiles were released...
October 17, 2016: Molecular Microbiology
Xiaojuan Huang, Jung-Ho Shin, Azul Pinochet-Barros, Tina T Su, John D Helmann
The Bacillus subtilis MntR metalloregulatory protein senses manganese, an essential element required for central metabolism, oxidative stress resistance and replication. An mntR null mutant is highly sensitive to Mn(II) intoxication, which is attributed in part to the constitutive expression of two importers: the proton-dependent NRAMP family transporter MntH and the ABC transporter MntABCD. Here, we show that an mntR null mutant is still sensitive to Mn(II) intoxication even if both of the import systems are absent...
October 17, 2016: Molecular Microbiology
Theodoric A Mattes, Jorge C Escalante-Semerena
5,6-Dimethylbenzimidazolyl-(DMB)-α-ribotide, [α-ribazole-5'-phosphate (α-RP)] is an intermediate in the biosynthesis of adenosylcobalamin (AdoCbl) in many prokaryotes. In such microbes, α-RP is synthesized by nicotinate mononucleotide (NaMN):DMB phosphoribosyltransferases (CobT in S. enterica), in a reaction that is considered to be the canonical step for the activation of the base of the nucleotide present in adenosylcobamides. Some Firmicutes lack CobT-type enzymes, but have a two-protein system comprised of a transporter (i...
October 17, 2016: Molecular Microbiology
Vanessa Tripp, Roman Martin, Alvaro Orell, Omer S Alkhnbashi, Rolf Backofen, Lennart Randau
Archaeal and eukaryotic organisms contain sets of C/D box s(no)RNAs with guide sequences that determine ribose 2'-O-methylation sites of target RNAs. The composition of these C/D box sRNA sets is highly variable between organisms and results in varying RNA modification patterns which are important for ribosomal RNA folding and stability. Little is known about the genomic organization of C/D box sRNA genes in archaea. Here, we aimed to obtain first insights into the biogenesis of these archaeal C/D box sRNAs and analyzed the genetic context of more than 300 archaeal sRNA genes...
October 14, 2016: Molecular Microbiology
Patricia L Tavormina, Matthias Y Kellermann, Chakkiath Paul Antony, Elitza Tocheva, Nathan Dalleska, Ashley J Jensen, David L Valentine, Kai-Uwe Hinrichs, Grant Jensen, Nicole Dubilier, Victoria J Orphan
In the deep ocean, the conversion of methane into derived carbon and energy drives the establishment of diverse faunal communities. Yet specific biological mechanisms underlying the introduction of methane-derived carbon into the food web remain poorly described, due to a lack of cultured representative deep-sea methanotrophic prokaryotes. Here, we characterize the response of the deep-sea aerobic methanotroph Methyloprofundus sedimenti to methane starvation and recovery. By combining lipid analysis, RNA analysis, and electron cryotomography, we show that M...
October 14, 2016: Molecular Microbiology
Z Schultzhaus, T B Johnson, B D Shaw
Cell growth necessitates extensive membrane remodeling events including vesicle fusion or fission, processes that are regulated by coat proteins. The hyphal cells of filamentous fungi concentrate both exocytosis and endocytosis at the apex. This investigation focuses on clathrin in Aspergillus nidulans, with the aim of understanding its role in membrane remodeling in growing hyphae. We examined clathrin heavy chain (ClaH-GFP) which localized to three distinct subcellular structures: late Golgi (trans-Golgi equivalents of filamentous fungi), which are concentrated just behind the hyphal tip but are intermittently present throughout all hyphal cells; the region of concentrated endocytosis just behind the hyphal apex (the "endocytic collar"); and small, rapidly moving puncta that were seen trafficking long distances in nearly all hyphal compartments...
October 14, 2016: Molecular Microbiology
Georgia Sioupouli, George Lambrinidis, Emmanuel Mikros, Sotiris Amillis, George Diallinas
NCS1 proteins are H(+) or Na(+) symporters responsible for the uptake of purines, pyrimidines or related metabolites in bacteria, fungi and some plants. Fungal NCS1 are classified into two evolutionary and structurally distinct subfamilies, known as Fur- and Fcy-like transporters. These subfamilies have expanded and functionally diversified by gene duplications. The Fur subfamily of the model fungus Aspergillus nidulans includes both major and cryptic transporters specific for uracil, 5-fluorouracil, allantoin or/and uric acid...
October 14, 2016: Molecular Microbiology
Jia-Yun C Tsai, Jacelyn M S Loh, Fiona Clow, Natalie Lorenz, Thomas Proft
Group A Streptococcus (GAS), or Streptococcus pyogenes, is a human pathogen that causes diseases ranging from skin and soft tissue infections to severe invasive diseases, such as toxic shock syndrome. Each GAS strain carries a particular pilus type encoded in the variable fibronectin-binding, collagen-binding, T antigen (FCT) genomic region. Here we describe the functional analysis of the serotype M2 pilus encoded in the FCT-6 region. We found that, in contrast to other investigated GAS pili, the ancillary pilin 1 lacks adhesive properties...
October 14, 2016: Molecular Microbiology
Kunzhi Zhang, Geng Wu, Hongzhi Tang, Chuanming Hu, Ting Shi, Ping Xu
Nicotine is an environmental toxicant in tobacco wastes, imposing severe hazards for the health of human and other mammalians. NicR2, a TetR-like repressor from Pseudomonas putida S16, plays a critical role in regulating nicotine degradation. Here, we determined the crystal structures of NicR2 and its complex with the inducer 6-hydroxy-3-succinoyl-pyridine (HSP). The N-terminal domain of NicR2 contains a conserved helix-turn-helix (HTH) DNA-binding motif, while the C-terminal domain contains a cleft for its selective recognition for HSP...
October 14, 2016: Molecular Microbiology
M Florencia Haurat, Ana Sofia Figueiredo, Lena Hoffmann, Lingling Li, Katharina Herr, Amanda Wilson, Morgan Beeby, Jörg Schaber, Sonja-Verena Albers
Organisms have evolved motility organelles that allow them to move to favorable habitats. Cells integrate environmental stimuli into intracellular signals to motility machineries to direct this migration. Many motility organelles are complex surface appendages that have evolved a tight, hierarchical regulation of expression. In the crenearchaeon Sulfolobus acidocaldarius, biosynthesis of the archaellum is regulated by regulatory network proteins that control expression of archaellum components in a phosphorylation-dependent manner...
October 12, 2016: Molecular Microbiology
Casandra Hoffman, Joshua Eby, Mary Gray, F Heath Damron, Jeffrey Melvin, Peggy Cotter, Erik Hewlett
Bordetella pertussis, the causative agent of whooping cough, secretes and releases adenylate cyclase toxin (ACT), which is a protein bacterial toxin that targets host cells and disarms immune defenses. ACT binds filamentous hemagglutinin (FHA), a surface-displayed adhesin, and until now, the consequences of this interaction were unknown. A B. bronchiseptica mutant lacking ACT produced more biofilm than the parental strain; leading Irie et al. to propose the ACT-FHA interaction could be responsible for biofilm inhibition...
October 12, 2016: Molecular Microbiology
Ana Maria Jorge, Jonathan Schneider, Sandra Unsleber, Nadine Göhring, Christoph Mayer, Andreas Peschel
The facultative pathogen Staphylococcus aureus colonizes the human anterior nares and causes infections of various organ systems. Which carbon, energy, and phosphate sources can be utilized by S. aureus in nutrient-poor habitats has remained largely unknown. We describe that S. aureus secretes a glycerophosphodiesterase (glycerophosphodiester phosphodiesterase, EC, GlpQ, degrading the glycerophosphodiester (GPD) head groups of phospholipids such as human phosphatidylcholine (GroPC). Deletion of glpQ completely abolished the GroPC-degrading activity in S...
October 11, 2016: Molecular Microbiology
Ewa Waclawek, Ewa Joachimiak, Malgorzata Hanna Hall, Hanna Fabczak, Dorota Wloga
Katanin is a microtubule severing protein that functions as a heterodimer composed of an AAA domain catalytic subunit, p60, and a regulatory subunit, a WD40 repeat protein, p80. Katanin-dependent severing of microtubules is important for proper execution of key cellular activities including cell division, migration, and differentiation. Published data obtained in C. elegans, Xenopus and mammals indicate that katanin is regulated at multiple levels including transcription, posttranslational modifications (of both katanin and microtubules) and degradation...
October 11, 2016: Molecular Microbiology
James Peek, Joseph Roman, Graham R Moran, Dinesh Christendat
Quinate and shikimate can be degraded by a number of microbes. Dehydroshikimate dehydratases (DSDs) play a central role in this process, catalyzing the conversion of 3-dehydroshikimate to protocatechuate, a common intermediate of aromatic degradation pathways. DSDs have applications in metabolic engineering for the production of valuable protocatechuate-derived molecules. Although a number of Gram-negative bacteria are known to catabolize quinate and shikimate, only limited information exists on the quinate/shikimate catabolic enzymes found in these organisms...
October 5, 2016: Molecular Microbiology
Alan D Goddard, Shilpa Bali, Despoina A I Mavridou, Victor M Luque-Almagro, Andrew J Gates, M Dolores Roldán, Simon Newstead, David J Richardson, Stuart J Ferguson
Nitrate and nitrite transport across biological membranes is often facilitated by protein transporters that are members of the major facilitator superfamily. Paracoccus denitrificans contains an unusual arrangement whereby two of these transporters, NarK1 and NarK2, are fused into a single protein, NarK, which delivers nitrate to the respiratory nitrate reductase and transfers the product, nitrite, to the periplasm. Our complementation studies, using a mutant lacking the nitrate/proton symporter NasA from the assimilatory nitrate reductase pathway, support that NarK1 functions as a nitrate/proton symporter while NarK2 is a nitrate/nitrite antiporter...
October 3, 2016: Molecular Microbiology
Kurni Kurniyati, John F Kelly, Evgeny Vinogradov, Anna Robotham, Youbing Tu, Juyu Wang, Jun Liu, Susan M Logan, Chunhao Li
While protein glycosylation has been reported in several spirochetes including the syphilis bacterium Treponema pallidum and Lyme disease pathogen Borrelia burgdorferi, the pertinent glycan structures and their roles remain uncharacterized. Herein, we report a novel glycan with an unusual chemical composition and structure in the oral spirochete Treponema denticola, a keystone pathogen of periodontitis. The identified glycan of mass 450.2 Da is composed of a monoacetylated nonulosonic acid (Non) with a novel extended N7 acyl modification, a 2-methoxy-4,5,6-trihydroxy-hexanoyl residue in which the Non has a pseudaminic acid configuration (L-glycero-L-manno) and is β-linked to serine or threonine residues...
October 1, 2016: Molecular Microbiology
Zhiming Ouyang, Jianli Zhou
Rrp2 encodes a putative bacterial enhancer binding protein (bEBP) in Borrelia burgdorferi. Point mutation (G239C) of Rrp2 abolishes the transcriptional activation of σ(54) -dependent rpoS. In contrast to canonical bEBPs that are dispensable for bacterial growth, Rrp2 is essential for borrelial growth in BSK medium. It has been believed that Rrp2's ATPase activity is not required for cell growth, but experimental evidence supporting this notion has been lacking. In particular, it has remained unclear whether the residue G239 is involved in Rrp2's presumptive ATPase activity...
October 1, 2016: Molecular Microbiology
Daniel Straume, Gro Anita Stamsås, Kari Helene Berg, Zhian Salehian, Leiv Sigve Håvarstein
The oval shape of pneumococci results from a combination of septal and lateral peptidoglycan synthesis. The septal cross-wall is synthesized by the divisome, while the elongasome drives cell elongation by inserting new peptidoglycan into the lateral cell wall. Each of these molecular machines contains penicillin-binding proteins (PBPs), which catalyze the final stages of peptidoglycan synthesis, plus a number of accessory proteins. Much effort has been made to identify these accessory proteins and determine their function...
September 29, 2016: Molecular Microbiology
Vinayak Singh, Neeraj Dhar, János Pató, Gaëlle S Kolly, Jana Korduláková, Martin Forbak, Joanna C Evans, Rita Székely, Jan Rybniker, Zuzana Palčeková, Júlia Zemanová, Isabella Santi, François Signorino-Gelo, Liliana Rodrigues, Anthony Vocat, Adrian S Covarrubias, Monica G Rengifo, Kai Johnsson, Sherry Mowbray, Joseph Buechler, Vincent Delorme, Priscille Brodin, Graham W Knott, José A Aínsa, Digby F Warner, György Kéri, Katarína Mikušová, John D McKinney, Stewart T Cole, Valerie Mizrahi, Ruben C Hartkoorn
There is an urgent need to discover new anti-tubercular agents with novel mechanisms of action in order to tackle the scourge of drug-resistant tuberculosis. Here, we report the identification of such a molecule - an AminoPYrimidine-Sulfonamide (APYS1) that has potent, bactericidal activity against M. tuberculosis. Mutations in APYS1-resistant M. tuberculosis mapped exclusively to wag31, a gene that encodes a scaffolding protein thought to orchestrate cell elongation. Recombineering confirmed that a Gln201Arg mutation in Wag31 was sufficient to cause resistance to APYS1, however, neither overexpression nor conditional depletion of wag31 impacted M...
September 28, 2016: Molecular Microbiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"