Crystal structure and functional implications of LprF fromMycobacterium tuberculosisandM. bovis

2014 ◽  
Vol 70 (10) ◽  
pp. 2619-2630 ◽  
Author(s):  
Jin-Sik Kim ◽  
Li Jiao ◽  
Jeong-Il Oh ◽  
Nam-Chul Ha ◽  
Yong-Hak Kim
Keyword(s):  
Crystal Structure ◽  
Cell Wall ◽  
Spectrometric Analysis ◽  
Alkyl Chains ◽  
Gram Positive Bacteria ◽  
Cavity Structure ◽  
Functional Implications ◽  
Causative Agents ◽  
Mycobacterial Cell Wall

The Gram-positive bacteriaMycobacterium tuberculosisandM. bovisare causative agents of tuberculosis in humans and cattle. The lipoprotein LprF is found inM. tuberculosisandM. bovisbut not in the nonpathogenicM. smegmatis. To date, the role of LprF remains to be elucidated. In this study, the crystal structure of LprF has been determined at 1.1 Å resolution. The overall structure is similar to that of a homologue, LprG, with a central hydrophobic cavity that binds a triacylated glycolipid. LprF exhibited a central cavity structure similar to that of LprG, but with a smaller cavity that binds two alkyl chains. Consistently, subsequent mass-spectrometric analysis revealed that the bound ligand was a diacylated glycolipid, as found in the structure. Furthermore, an increased ratio of lipoarabinomannan to lipomannan in the mycobacterial cell wall was observed whenlprFwas introduced intoM. smegmatis. These observations suggested that LprF transfers the diacylated glycolipid from the plasma membrane to the cell wall, which might be related to the pathogenesis of the bacteria.

scholarly journals Crystal Structure of DsbA from Corynebacterium diphtheriae and Its Functional Implications for CueP in Gram-Positive Bacteria

2015 ◽  
Vol 38 (8) ◽  
pp. 715-722 ◽  
Author(s):  
Si-Hyeon Um ◽  
Jin-Sik Kim ◽  
Saemee Song ◽  
Nam Ah Kim ◽  
Seong Hoon Jeong ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Corynebacterium Diphtheriae ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Functional Implications

scholarly journals Conjunctivities of newborns

2021 ◽  
Vol 16 (2) ◽  
pp. 31-39
Author(s):  
Elvira I. Saidasheva ◽  
Svetlana V. Buianovskaia
Keyword(s):  
Culture Media ◽  
Laboratory Diagnostics ◽  
Minimal Amount ◽  
Anterior Section ◽  
Gram Positive Bacteria ◽  
Leading Role ◽  
Bacteriological Method ◽  
Causative Agents ◽  
Neonatal Conjunctivitis

The article is focused on the peculiarities of the clinical course of separate forms of neonatal conjunctivitis, depending on the etiological factor. It was found that more often the disease refers to nosocomial eye infection and bacterial nature. We performed the bacteriological analysis of the contents of the conjunctival cavity of 50 newborn patients being treated in the neonatal department. Our analysis indicated the leading role of gram-positive bacteria Staph. epidermidis (59.7%) and Staph. aureus (21.7%) in the development of the inflammatory process. The share of other types of pathogens, including gram-negative minor and various pathogens, is from 0.54% to 3.2%. The cause of nosocomial infection is considered to be the pathogen that circulates in the department and acquires the features of a hospital strain. These are consistent with the results of similar studies conducted by both domestic and foreign clinicians, which are also presented in the article. Particular attention is paid to the causative agents of intrauterine infections that are dangerous for the anterior section: gonococcus, chlamydia, herpes simplex, etc. These agents often cause serious diseases in newborns (gonoblenorrhea, ophthalmic chlamydiosis, and ophthalmic herpes), in which the cornea and vision are often affected. The article highlights the measures of primary prevention of intrapartum infection of the ocular surface in newborns, adopted in Russia. The paper presents modern approaches to selecting drugs for local antibacterial therapy of neonatal conjunctivitis, considering age restrictions for their use. Methods of laboratory diagnostics and their validity for the etiology of conjunctivitis have been described in detail. For example, the bacteriological method (inoculations in various culture media) is considered a reference (specificity 100%). The culture medium can be used to isolate bacteria, chlamydia, and mycoplasma, which allows getting clear results even with a minimal amount of microflora

scholarly journals Sortase B, a New Class of Sortase in Listeria monocytogenes

2004 ◽  
Vol 186 (7) ◽  
pp. 1972-1982 ◽  
Author(s):  
Hélène Bierne ◽  
Caroline Garandeau ◽  
M. Graciela Pucciarelli ◽  
Christophe Sabet ◽  
Salete Newton ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Virulence Factor ◽  
Cultured Cells ◽  
Surface Proteins ◽  
Gram Positive Bacteria ◽  
New Class ◽  
Sorting Motif

ABSTRACT Sortases are transamidases that covalently link proteins to the peptidoglycan of gram-positive bacteria. The genome of the pathogenic bacterium Listeria monocytogenes encodes two sortases genes, srtA and srtB. The srtA gene product anchors internalin and some other LPXTG-containing proteins to the listerial surface. Here, we focus on the role of the second sortase, SrtB. Whereas SrtA acts on most of the proteins in the peptidoglycan fraction, SrtB appears to target minor amounts of surface polypeptides. We identified one of the SrtB-anchored proteins as the virulence factor SvpA, a surface-exposed protein which does not contain the LPXTG motif. Therefore, as in Staphylococcus aureus, the listerial SrtB represents a second class of sortase in L. monocytogenes, involved in the attachment of a subset of proteins to the cell wall, most likely by recognizing an NXZTN sorting motif. The ΔsrtB mutant strain does not have defects in bacterial entry, growth, or motility in tissue-cultured cells and does not show attenuated virulence in mice. SrtB-mediated anchoring could therefore be required to anchor surface proteins involved in the adaptation of this microorganism to different environmental conditions.

scholarly journals Attenuation of Mycobacterium tuberculosis by Disruption of a mas-Like Gene or a Chalcone Synthase-Like Gene, Which Causes Deficiency in Dimycocerosyl Phthiocerol Synthesis

2003 ◽  
Vol 185 (10) ◽  
pp. 2999-3008 ◽  
Author(s):  
Tatiana D. Sirakova ◽  
Vinod S. Dubey ◽  
Michael H. Cynamon ◽  
Pappachan E. Kolattukudy
Keyword(s):  
Cell Wall ◽  
Target Gene ◽  
Chalcone Synthase ◽  
Lipid Synthesis ◽  
New Targets ◽  
Resistant Tuberculosis ◽  
Hygromycin Resistance Gene ◽  
The Many ◽  
Mycobacterial Cell Wall

ABSTRACT Tuberculosis is one of the leading preventable causes of death. Emergence of drug-resistant tuberculosis makes the discovery of new targets for antimycobacterial drugs critical. The unique mycobacterial cell wall lipids are known to play an important role in pathogenesis, and therefore the genes responsible for their biosynthesis offer potential new targets. To assess the possible role of some of the genes potentially involved in cell wall lipid synthesis, we disrupted a mas-like gene, msl7, and a chalcone synthase-like gene, pks10, with phage-mediated delivery of the disruption construct, in which the target gene was disrupted by replacement of an internal segment with the hygromycin resistance gene (hyg). Gene disruption by allelic exchange in the case of each disruptant was confirmed by PCR and Southern blot analyses. Neither msl7 nor pks10 mutants could produce dimycocerosyl phthiocerol, although both could produce mycocerosic acids. Thus, it is concluded that these gene products are involved in the biosynthesis of phthiocerol. Both mutants were found to be attenuated in a murine model, supporting the hypothesis that dimycocerosyl phthiocerol is a virulence factor and thus the many steps involved in its biosynthesis offer potential novel targets for antimycobacterial therapy.

scholarly journals Bacterial Growth and Cell Division: a Mycobacterial Perspective

2008 ◽  
Vol 72 (1) ◽  
pp. 126-156 ◽  
Author(s):  
Erik C. Hett ◽  
Eric J. Rubin
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Active Tuberculosis ◽  
Gram Negative Bacteria ◽  
Complex Cell ◽  
Causative Agents ◽  
The Many ◽  
Mycobacterial Cell Wall ◽  
Wall Components ◽  
Normal Architecture

SUMMARY The genus Mycobacterium is best known for its two major pathogenic species, M. tuberculosis and M. leprae, the causative agents of two of the world's oldest diseases, tuberculosis and leprosy, respectively. M. tuberculosis kills approximately two million people each year and is thought to latently infect one-third of the world's population. One of the most remarkable features of the nonsporulating M. tuberculosis is its ability to remain dormant within an individual for decades before reactivating into active tuberculosis. Thus, control of cell division is a critical part of the disease. The mycobacterial cell wall has unique characteristics and is impermeable to a number of compounds, a feature in part responsible for inherent resistance to numerous drugs. The complexity of the cell wall represents a challenge to the organism, requiring specialized mechanisms to allow cell division to occur. Besides these mycobacterial specializations, all bacteria face some common challenges when they divide. First, they must maintain their normal architecture during and after cell division. In the case of mycobacteria, that means synthesizing the many layers of complex cell wall and maintaining their rod shape. Second, they need to coordinate synthesis and breakdown of cell wall components to maintain integrity throughout division. Finally, they need to regulate cell division in response to environmental stimuli. Here we discuss these challenges and the mechanisms that mycobacteria employ to meet them. Because these organisms are difficult to study, in many cases we extrapolate from information known for gram-negative bacteria or more closely related GC-rich gram-positive organisms.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Sign in / Sign up

Export Citation Format

Share Document