Proteins of the secretin family form large macromolecular complexes, which assemble in outer membrane Gram-negative bacteria. Secretins are major components type II and III secretion systems linked to extrusion IV pili (T4P) DNA uptake. By electron cryo-tomography whole Thermus thermophilus cells, we determined situ structure a T4P molecular machine open closed state. Comparison reveals conformational change whereby N-terminal domains central PilQ shift by ~30 Å, two periplasmic gates make...

Acinetobacter baumannii causes a broad range of opportunistic infections in humans. Its success as an emerging pathogen is due to combination increasing antibiotic resistance, environmental persistence and adaptation the human host. To date very little known about molecular basis latter. Here we demonstrate that A. can use phosphatidylcholine, integral part cell membranes, sole carbon energy source. We report on identification three phospholipases belonging PLD superfamily. PLD1 PLD2 appear...

Acinetobacter baumannii is an important nosocomial pathogen. Mechanisms that allow A. to cause human infection are still poorly understood. Iron essential nutrient for bacterial growth in vivo, and the multiplicity of iron uptake systems suggests acquisition contributes ability infection. In Gram-negative bacteria, active transport ferrisiderophores heme relies on conserved TonB-ExbB-ExbD energy-transducing complex, while ferrous mediated by Feo system. The genome invariably contains three...

Abstract Type IV pili are flexible filaments on the surface of bacteria, consisting a helical assembly pilin proteins. They involved in bacterial motility (twitching), adhesion, biofilm formation and DNA uptake (natural transformation). Here, we use cryo-electron microscopy mass spectrometry to show that bacterium Thermus thermophilus produces two forms type pilus (‘wide’ ‘narrow’), differing structure protein composition. Wide composed major PilA4, while narrow so-far uncharacterized which...

Currently, the viable but non-culturable (VBNC) state is an underappreciated niche for pathogenic bacteria which provides a continuous source recurrent infections and transmission. We propose VBNC to be global persistence mechanism used by various A. baumannii strains cope with many stresses it confronted in clinical environment host. This requires novel strategy detect cells of this pathogen that not only based on plating assays.

We have identified pobR, a gene encoding transcriptional activator that regulates expression of pobA, the structural for p-hydroxybenzoate hydroxylase (PobA) in Acinetobacter calcoaceticus ADP1. Inducible cloned pobA Escherichia coli depended upon presence functional pobR gene, and mutations within prevented A. calcoaceticus. A pobA-lacZ operon fusion was used to demonstrate is enhanced up 400-fold by inducer p-hydroxybenzoate. Inducer concentrations as low 10(-7) M were sufficient elicit...

Summary A cinetobacter baylyi , a ubiquitous soil bacterium, can cope with high salinity by uptake of choline as precursor the compatible solute glycine betaine. Here, we report on identification dehydrogenase ( BetA ) and betaine aldehyde BetB mediating oxidation to The betAB genes were found form an operon together potential transcriptional regulator betI . transcription betIBA two recently identified transporters was upregulated in response plus salt. finding that osmo‐independent...

ABSTRACT Thermus thermophilus HB27, an extremely thermophilic bacterium, exhibits high competence for natural transformation. To identify genes of the transformation machinery T. we performed homology searches in partially completed genomic sequence conserved genes. These analyses resulted detection 28 open reading frames (ORFs) exhibiting significant similarities to known proteins gram-negative and gram-positive bacteria. Disruption 15 selected potential led identification 8 noncompetent...

Rhodococcus erythropolis BD2, which is able to utilize isopropylbenzene as a sole carbon and energy source, was shown contain conjugative linear plasmid, pBD2. The estimated size of pBD2 208 212 kb. Linear plasmid-deficient strains had lost both the degradation trichloroethene characteristics, well arsenite resistance mercury phenotypes. Reintroduction restored all four characteristics. Conjugational transfer plasmidless mutant strain BD2 other R. occurred at frequencies between 3.5 x 10(-5)...

ABSTRACT The mesophile Acinetobacter sp. strain BD413 and the extreme thermophile Thermus thermophilus HB27 display high frequencies of natural transformation. In this study we identified characterized a novel competence gene in BD413, comA , whose product displays significant similarities to proteins ComA ComEC Neisseria Bacillus species. Transcription correlated with growth phase-dependent transcriptional regulation recently pilin-like factors transformation machinery. This finding...

Secretins are a family of large bacterial outer membrane protein complexes mediating the transport complex structures, such as type IV pili, DNA and filamentous phage, or various proteins, extracellular enzymes pathogenicity determinants. PilQ thermophilic bacterium Thermus thermophilus HB27 is member secretin required for natural transformation. Here we report isolation, structural, functional analyses unique from T. thermophilus. Native PAGE, gel filtration chromatography, electrophoretic...

Acidic glycerophospholipids play an important role in determining the resistance of Gram-negative bacteria to stress conditions and antibiotics. Acinetobacter baumannii, opportunistic human pathogen which is responsible for increasing number nosocomial infections, exhibits broad antibiotic resistances. Here lipids A. baumannii have been analyzed by combined MALDI-TOF/MS TLC analyses; addition GC-MS analyses fatty acid methyl esters released methanolysis membrane phospholipids performed. The...

Acinetobacter baumannii is an emerging opportunistic pathogen, responsible for up to 10% of gram-negative, nosocomial infections. The global increase multidrug-resistant and pan-resistant isolates presents clinicians with formidable challenges. To establish a persistent infection, A. must overcome the detrimental effects complement as first line defense against invading microorganisms. However, immune evasion principles underlying serum resistance in remain elusive. Here, we identified novel...

The cyclic dinucleotide c‐di‐GMP is an important second messenger molecule in bacteria and interacts with a variety of receptor molecules including RNA protein domains. An class c‐di‐GMP‐binding domains are the general secretory pathway type II (GSPII) as exemplified by N‐terminal domain ATPase MshE from Vibrio cholerae (MshEN). MshEN binds monomeric via two consecutive copies 24‐residue sequence motif, which form compact 4‐α‐helical bundle. PilF Thermus thermophilus regulates pilus...

Rhodococcus corallinus (formerly Nocardia corallina) B-276, isolated with propene as sole carbon and energy source, is able to oxidize trichloroethene (TCE). Glucose- or propene-grown R. B-276 cells exhibited no difference in TCE degradation efficiency. was found be growth-phase-dependent maximum rates were monitored stationary-phase cells. K m V max values for of grown nutrient broth medium the presence glucose 187 μM 2·4 nmol min-1 (mg protein)-1, respectively. Escherichia coli...

The complete nucleotide sequence of the linear plasmid pBD2 from Rhodococcus erythropolis BD2 comprises 210,205 bp. Sequence analyses revealed 212 putative open reading frames (ORFs), 97 which had an annotatable function. These ORFs could be assigned to six functional groups: replication and maintenance, transport metalloresistance, catabolism, transposition, regulation, protein modification. Many transposon-related sequences were found flank isopropylbenzene pathway genes. This finding...

ABSTRACT Two structurally different appendages, thin and thick pili, are found in members of the genus Acinetobacter . The presence pilus structures correlates with phenotypes, such as adherence to surfaces, a trait not only observed pathogenic species, well motility. However, their distinct individual roles were unknown. To characterize role pili physiology , we isolated from cell surface sp. strain BD413 (recently recognized representative baylyi ), soil bacterium that rapidly takes up...

The natural transformation system of the thermophilic bacterium Thermus thermophilus HB27 comprises at least 16 distinct competence proteins encoded by seven loci. In this article, we present for first time biochemical analyses PilMNOWQ and PilA4, demonstrate that pilMNOWQ genes are each essential transformation. We identified three different forms one with an apparent molecular mass 14 kDa, which correlates deduced protein, 18‐kDa form a 23‐kDa form; last was found to be glycosylated. PilM,...

Secretins form multimeric channels across the outer membrane of Gram-negative bacteria that mediate import or export substrates and/or extrusion type IV pili. The secretin complex Thermus thermophilus is an oligomer 757-residue PilQ protein, essential for DNA uptake and pilus extrusion. Here, we present cryo-EM structure this bifunctional at a resolution ~7 Å using new reconstruction protocol. Thirteen protomers large periplasmic domain six stacked rings in membrane. A homology model protein...