scholarly journals Inactivation of the srtA Gene inStreptococcus gordonii Inhibits Cell Wall Anchoring of Surface Proteins and Decreases In Vitro and In Vivo Adhesion

2001 ◽  
Vol 69 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Tové C. Bolken ◽  
Christine A. Franke ◽  
Kevin F. Jones ◽  
Gloria O. Zeller ◽  
C. Hal Jones ◽  
...  

ABSTRACT The srtA gene product, SrtA, has been shown to be required for cell wall anchoring of protein A as well as virulence in the pathogenic bacterium Staphylococcus aureus. There are five major mechanisms for displaying proteins at the surface of gram-positive bacteria (P. Cossart and R. Jonquieres, Proc. Natl. Acad. Sci. USA 97:5013–5015, 2000). However, since many of the known surface proteins of gram-positive bacteria are believed to be exported and anchored via the sortase pathway, it was of interest to determine ifsrtA plays a similar role in other gram-positive bacteria. To that end, the srtA gene in the human oral commensal organism Streptococcus gordonii was insertionally inactivated. The srtA mutant S. gordoniiexhibited a marked reduction in quantity of a specific anchored surface protein. Furthermore, the srtA mutant had reduced binding to immobilized human fibronectin and had a decreased ability to colonize the oral mucosa of mice. Taken together, these results suggest that the activity of SrtA plays an important role in the biology of nonpathogenic as well as pathogenic gram-positive cocci.

2002 ◽  
Vol 70 (3) ◽  
pp. 1382-1390 ◽  
Author(s):  
Caroline Garandeau ◽  
Hélène Réglier-Poupet ◽  
Iharilalao Dubail ◽  
Jean-Luc Beretti ◽  
Patrick Berche ◽  
...  

ABSTRACT Listeria monocytogenes is an intracellular gram-positive human pathogen that invades eucaryotic cells. Among the surface-exposed proteins playing a role in this invasive process, internalin belongs to the family of LPXTG proteins, which are known to be covalently linked to the bacterial cell wall in gram-positive bacteria. Recently, it has been shown in Staphylococcus aureus that the covalent anchoring of protein A, a typical LPXTG protein, is due to a cysteine protease, named sortase, required for bacterial virulence. Here, we identified in silico from the genome of L. monocytogenes a gene, designated srtA, encoding a sortase homologue. The role of this previously unknown sortase was studied by constructing a sortase knockout mutant. Internalin was used as a reporter protein to study the effects of the srtA mutation on cell wall anchoring of this LPXTG protein in L. monocytogenes. We show that the srtA mutant (i) is affected in the display of internalin at the bacterial surface, (ii) is significantly less invasive in vitro, and (iii) is attenuated in its virulence in the mouse. These results demonstrate that srtA of L. monocytogenes acts as a sortase and plays a role in the pathogenicity.


2018 ◽  
Vol 84 (8) ◽  
pp. e00114-18 ◽  
Author(s):  
Lu Zhang ◽  
Yanqiang Liu ◽  
Yunpeng Yang ◽  
Weihong Jiang ◽  
Yang Gu

ABSTRACTThe master regulator CcpA (catabolite control protein A) manages a large and complex regulatory network that is essential for cellular physiology and metabolism in Gram-positive bacteria. Although CcpA can affect the expression of target genes by binding to acis-acting catabolite-responsive element (cre), whether and how the expression of CcpA is regulated remain poorly explored. Here, we report a novel dual-cremotif that is employed by the CcpA inClostridium acetobutylicum, a typical solventogenicClostridiumspecies, for autoregulation. Twocresites are involved in CcpA autoregulation, and they reside in the promoter and coding regions of CcpA. In this dual-cremotif,creP, in the promoter region, positively regulatesccpAtranscription, whereascreORF, in the coding region, negatively regulates this transcription, thus enabling two-way autoregulation of CcpA. Although CcpA boundcrePmore strongly thancreORFin vitro, thein vivoassay showed thatcreORF-based repression dominates CcpA autoregulation during the entire fermentation. Finally, a synonymous mutation ofcreORFwas made within the coding region, achieving an increased intracellular CcpA expression and improved cellular performance. This study provides new insights into the regulatory role of CcpA inC. acetobutylicumand, moreover, contributes a new engineering strategy for this industrial strain.IMPORTANCECcpA is known to be a key transcription factor in Gram-positive bacteria. However, it is still unclear whether and how the intracellular CcpA level is regulated, which may be essential for maintaining normal cell physiology and metabolism. We discovered here that CcpA employs a dual-cremotif to autoregulate, enabling dynamic control of its own expression level during the entire fermentation process. This finding answers the questions above and fills a void in our understanding of the regulatory network of CcpA. Interference in CcpA autoregulation leads to improved cellular performance, providing a new useful strategy in genetic engineering ofC. acetobutylicum. Since CcpA is widespread in Gram-positive bacteria, including pathogens, this dual-cre-based CcpA autoregulation would be valuable for increasing our understanding of CcpA-based global regulation in bacteria.


1999 ◽  
Vol 63 (1) ◽  
pp. 174-229 ◽  
Author(s):  
William Wiley Navarre ◽  
Olaf Schneewind

SUMMARY The cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. The cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. All of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. Two basic mechanisms, cell wall sorting and targeting, have been identified. Cell well sorting is the covalent attachment of surface proteins to the peptidoglycan via a C-terminal sorting signal that contains a consensus LPXTG sequence. More than 100 proteins that possess cell wall-sorting signals, including the M proteins of Streptococcus pyogenes, protein A of Staphylococcus aureus, and several internalins of Listeria monocytogenes, have been identified. Cell wall targeting involves the noncovalent attachment of proteins to the cell surface via specialized binding domains. Several of these wall-binding domains appear to interact with secondary wall polymers that are associated with the peptidoglycan, for example teichoic acids and polysaccharides. Proteins that are targeted to the cell surface include muralytic enzymes such as autolysins, lysostaphin, and phage lytic enzymes. Other examples for targeted proteins are the surface S-layer proteins of bacilli and clostridia, as well as virulence factors required for the pathogenesis of L. monocytogenes (internalin B) and Streptococcus pneumoniae (PspA) infections. In this review we describe the mechanisms for both sorting and targeting of proteins to the envelope of gram-positive bacteria and review the functions of known surface proteins.


2006 ◽  
Vol 70 (1) ◽  
pp. 192-221 ◽  
Author(s):  
Luciano A. Marraffini ◽  
Andrea C. DeDent ◽  
Olaf Schneewind

SUMMARY The cell wall envelopes of gram-positive bacteria represent a surface organelle that not only functions as a cytoskeletal element but also promotes interactions between bacteria and their environment. Cell wall peptidoglycan is covalently and noncovalently decorated with teichoic acids, polysaccharides, and proteins. The sum of these molecular decorations provides bacterial envelopes with species- and strain-specific properties that are ultimately responsible for bacterial virulence, interactions with host immune systems, and the development of disease symptoms or successful outcomes of infections. Surface proteins typically carry two topogenic sequences, i.e., N-terminal signal peptides and C-terminal sorting signals. Sortases catalyze a transpeptidation reaction by first cleaving a surface protein substrate at the cell wall sorting signal. The resulting acyl enzyme intermediates between sortases and their substrates are then resolved by the nucleophilic attack of amino groups, typically provided by the cell wall cross bridges of peptidoglycan precursors. The surface protein linked to peptidoglycan is then incorporated into the envelope and displayed on the microbial surface. This review focuses on the mechanisms of surface protein anchoring to the cell wall envelope by sortases and the role that these enzymes play in bacterial physiology and pathogenesis.


2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.


2005 ◽  
Vol 49 (6) ◽  
pp. 2498-2500 ◽  
Author(s):  
Eun Jeong Yoon ◽  
Yeong Woo Jo ◽  
Sung Hak Choi ◽  
Tae Ho Lee ◽  
Jae Keol Rhee ◽  
...  

ABSTRACT In vitro and in vivo activities of DA-7867 were assessed against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and penicillin-resistant Streptococcus pneumoniae. All isolates were inhibited by DA-7867 at ≤0.78 μg/ml, a four-times-lower concentration than that of inhibition by linezolid. For murine infection models, DA-7867 also exhibited greater efficacy than linezolid against all isolates tested.


2015 ◽  
Vol 25 (2-3) ◽  
pp. 79-93 ◽  
Author(s):  
Joseph W. Lengeler

<b><i>Past:</i></b> The title ‘PTS 50 or The PTS after 50 years' relies on the first description in 1964 of the phosphoenolpyruvate-dependent carbohydrate:phosphotransferase system (PTS) by Kundig, Gosh and Roseman [Proc Natl Acad Sci USA 1964;52:1067-1074]. The system comprised proteins named Enzyme I, HPr and Enzymes II, as part of a novel PTS for carbohydrates in Gram-negative and Gram-positive bacteria, whose ‘biological significance remained unclear'. In contrast, studies which would eventually lead to the discovery of the central role of the PTS in bacterial metabolism had been published since before 1942. They are primarily linked to names like Epps and Gale, J. Monod, Cohn and Horibata, and B. Magasanik, and to phenomena like ‘glucose effects', ‘diauxie', ‘catabolite repression' and carbohydrate transport. <b><i>Present:</i></b> The pioneering work from Roseman's group initiated a flood of publications. The extraordinary progress from 1964 to this day in the qualitative and in vitro description of the genes and enzymes of the PTS, and of its multiple roles in global cellular control through ‘inducer exclusion', gene induction and ‘catabolite repression', in cellular growth, in cell differentiation and in chemotaxis, as well as the differences of its functions between Gram-positive and Gram-negative bacteria, was one theme of the meeting and will not be treated in detail here. <b><i>Future:</i></b> At the 1988 Paris meeting entitled ‘The PTS after 25 years', Saul Roseman predicted that ‘we must describe these interactions [of the PTS components] in a quantitative way [under] in vivo conditions'. I will present some results obtained by our group during recent years on the old phenomenon of diauxie by means of very fast and quantitative tests, measured in vivo, and obtained from cultures of isogenic mutant strains growing under chemostat conditions. The results begin to hint at the problems relating to future PTS research, but also to the ‘true science' of Roseman.


RSC Advances ◽  
2014 ◽  
Vol 4 (99) ◽  
pp. 56031-56040 ◽  
Author(s):  
Ilaria Rago ◽  
Chandrakanth Reddy Chandraiahgari ◽  
Maria P. Bracciale ◽  
Giovanni De Bellis ◽  
Elena Zanni ◽  
...  

ZnO micro and nanorods, produced through simple and inexpensive techniques, resulted to be strong antimicrobials against Gram-positive bacteria, in vitro as well as in vivo, by altering cell outer structures like membrane and exopolysaccharides.


2019 ◽  
Vol 20 (2) ◽  
Author(s):  
Anna Kędzia ◽  
Elżbieta Hołderna-Kędzia

Introduction. Cypress (Cupressus sempervirens L.) belongs to the family Cupressaceae. It is evergreen, and grows in Mediterranean region. The Cypress leaves and young branches are utilized to produce the essential oil. Cypress oil contain a number of components, in it α-pinene, Δ3-carene, α-terpinyl acetate, cedrol, α-terpinolene, β-myrcene, limonene, α-terpineolene, terpinen-4-ol, β-pinene, δ-cadinene and sabinene. The oil is used in therapy different diseases. It to have antimicrobial activity. Aim. The aim of the date was evaluation the susceptibility of anaerobic bacteria to Cypress oil. Material and methods. The anaerobic bacteria were isolated from patients. The 62 microorganisms, in it 36 strains of Gram-negative rods, 14 Gram-positive cocci and 12 Gram-positive rods, and 7 reference strains were tested. Susceptibility (MIC) was determined by means of plate dilution technique in Brucella agar supplemented with 5% defibrynated sheep blood, menadione and hemin. The Cypress oil was dissolved in DMSO and distilled water to obtain final following concentrations: 2.5, 5.0, 7.5, 10.0, 15.0 and 20.0 mg/ml. Inoculum containing 106 CFU per 1 ml was seeded with Steers replicator upon the agar with oil or without the oil (strains growth control). The agar plates was incubated in anaerobic condition in anaerobic jar in 37°C for 48 hrs. The MIC was interpreted as the lowest concentration of Cypress oil inhibiting the growth of tested bacteria. Results. The results indicated that from among Gram-negative rods the most susceptible to Cypress oil was the strains from genus Tannerella forsythia (MIC < 2.5-5.0 mg/ml), Bacteroides uniformis (MIC = 5.0 mg/ml), Bacteroides vulgatus and Porphyromonas asaccharolytica (MIC 5.0-7.5 mg/ml) and Porphyromonas levii (MIC = 7.5 mg/ml). The strains from genera Fusobacterium and of Bacteroides fragilis were the susceptible to 2.5-≥ 20.0 mg/ml. The Cypress oil was least active towards Prevotella and Parabacteroides strains (MIC ≥ 20.0 mg/ml).The tested Gram-positive cocci were more susceptible. The growth of the strains were inhibited by concentrations in ranges ≤ 2.5-7.5 mg/ml. The oil was minor active towards Gram-positive rods (MIC ≤ 2.5-20.0 mg/ml). Among the strains the genus of Actinomyces odontolyticus (MIC = 5.0 mg/ml) and Actinomyces viscosus (MIC ≤ 2.5-7.5 mg/ml) were the most susceptible. The growth of rods of Bifidobacterium breve was inhibited by concentrations 10.0 mg/ml. The data indicates that the Gram-negative rods were the less susceptible than Gram-positive bacteria to cypress oil. Conclusions. Among Gram-negative rods the most susceptible were the strains Tannerella forsythia, Bacteroides uniformis, Bacteroides vulgatus, Porphyromonas asaccharolytica and Porphyromonas levii. The oil was more active against Gram-positive cocci. Gram-positive anaerobic bacteria demonstrate the more susceptible to Cypress oil then Gram-positive rods.


2021 ◽  
Author(s):  
Xiang-Na Guan ◽  
Tao Zhang ◽  
Teng Yang ◽  
Ze Dong ◽  
Song Yang ◽  
...  

The housekeeping sortase A (SrtA), a membrane-associated cysteine transpeptidase, is responsible for anchoring surface proteins to the cell wall peptidoglycan in Gram-positive bacteria. This process is essential for the regulation...


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