scholarly journals Autolysis of Lactococcus lactis Is Influenced by Proteolysis

1998 ◽  
Vol 180 (22) ◽  
pp. 5947-5953 ◽  
Author(s):  
Girbe Buist ◽  
Gerard Venema ◽  
Jan Kok
Keyword(s):  
Cell Wall ◽  
Stationary Phase ◽  
Lactococcus Lactis ◽  
Deletion Mutant ◽  
Stationary Phase Culture ◽  
Intracellular Proteins ◽  
Phase Culture ◽  
A Cell ◽  
Zymographic Analysis ◽  
High Level

ABSTRACT The autolysin AcmA of Lactococcus lactis was shown to be degraded by the extracellular lactococcal proteinase PrtP. Autolysis, as evidenced by reduction in optical density of a stationary-phase culture and concomitant release of intracellular proteins, was greatly reduced when L. lactis MG1363 cells expressed the cell wall-anchored lactococcal proteinase PrtP of the PI-type caseinolytic specificity (PI). On the other hand, lactococcal strains that did not produce the proteinase showed a high level of autolysis, which was also observed when the cells produced the secreted form of PI or a cell wall-anchored proteinase with PIII-type specificity. Autolysis was also increased when MG1363 expressed the cell wall-anchored hybrid PI/PIII-type proteinase PIac. Zymographic analysis of AcmA activity during stationary phase showed that AcmA was quickly degraded by PI and much more slowly by PrtP proteinases with PIII-type and intermediate specificities. Autolysis of L. lactis by AcmA was influenced by the specificity, amount, and location of the lactococcal proteinase. No autolysis was observed when the various proteinases were expressed in an L. lactis acmAdeletion mutant, indicating that PrtP itself did not cause lysis of cells. The chain length of a strain was significantly shortened when the strain expressed a cell wall-anchored active proteinase.

scholarly journals Possible odour-mediated attraction of flies to Bacillus subtilis NRS-762 stationary phase culture

2015 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Volatile Compound ◽  
Stationary Phase Culture ◽  
Phase Culture ◽  
A Cell ◽  
Short And Long Term ◽  
Orbital Shaker

Signalling helps connects different organisms in the biosphere. This research note describes the possible concentration-dependent odour mediated attraction of flies to stationary phase aerobic liquid cultures of Bacillus subtilis NRS-762 cultivated on an open orbital shaker at 25 oC. Greater odour pungency correlated with more intense “foraging” attempts, which suggested the compounds’ possible behaviour modifying effects. Additionally, co-occurrence of optical density decline and increase in odour pungency suggested volatile compound(s) secretion might be a cell survival response mediated by a cell density-based signalling mechanism. Flies were not attracted to odourous stationary phase cultures of other common bacteria (Escherichia coli DH5α, Pseudomonas aeruginosa PRD-10, and Pseudomonas protegens Pf-5, which suggested species-specificity of the volatile compound(s)). Altogether, volatile compound(s) might serve as interkingdom messengers to enlist flies for dispersing B. subtilis to habitats with more favourable conditions in coping with possible irreversible decline in habitability, and operate in parallel with other in situ mechanisms such as cannibalism and sporulation that help B. subtilis ride out short- and long-term environmental fluctuations, respectively. Interested researchers are invited to build upon the preliminary findings.

scholarly journals Possible odour-mediated attraction of flies to Bacillus subtilis NRS-762 stationary phase culture

2015 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Volatile Compound ◽  
Stationary Phase Culture ◽  
Phase Culture ◽  
A Cell ◽  
Short And Long Term ◽  
Orbital Shaker

Signalling helps connects different organisms in the biosphere. This research note describes the possible concentration-dependent odour mediated attraction of flies to stationary phase aerobic liquid cultures of Bacillus subtilis NRS-762 maintained on an open orbital shaker at 25 oC. Greater odour pungency was observed to correlate with more intense “foraging” attempts, which suggested the compounds’ possible behaviour modifying effects. Additionally, co-occurrence of optical density decline and increase in odour pungency suggested volatile compound(s) secretion might be a cell survival response mediated by a cell density-based signalling mechanism. Flies were not attracted to odourous stationary phase cultures of other common bacteria (Escherichia coli DH5α, Pseudomonas aeruginosa PRD-10, and Pseudomonas protegens Pf-5, which suggested species-specificity of the volatile compound(s). Altogether, volatile compound(s) might serve as interkingdom messengers to enlist flies for dispersing B. subtilis to habitats with more favourable conditions in coping with possible irreversible decline in habitability, and operate in parallel with other in situ mechanisms such as cannibalism and sporulation that help B. subtilis ride out short- and long-term environmental fluctuations, respectively. Interested researchers are invited to build upon the preliminary findings.

scholarly journals Possible odour-mediated attraction of flies to Bacillus subtilis NRS-762 stationary phase culture

2015 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Volatile Compound ◽  
Stationary Phase Culture ◽  
Phase Culture ◽  
A Cell ◽  
Short And Long Term ◽  
Orbital Shaker

Signalling helps connects different organisms in the biosphere. This research note describes the possible concentration-dependent odour mediated attraction of flies to stationary phase aerobic liquid cultures of Bacillus subtilis NRS-762 cultivated on an open orbital shaker at 25 oC. Greater odour pungency correlated with more intense “foraging” attempts, which suggested the compounds’ possible behaviour modifying effects. Additionally, co-occurrence of optical density decline and increase in odour pungency suggested volatile compound(s) secretion might be a cell survival response mediated by a cell density-based signalling mechanism. Flies were not attracted to odourous stationary phase cultures of other common bacteria (Escherichia coli DH5α, Pseudomonas aeruginosa PRD-10, and Pseudomonas protegens Pf-5, which suggested species-specificity of the volatile compound(s)). Altogether, volatile compound(s) might serve as interkingdom messengers to enlist flies for dispersing B. subtilis to habitats with more favourable conditions in coping with possible irreversible decline in habitability, and operate in parallel with other in situ mechanisms such as cannibalism and sporulation that help B. subtilis ride out short- and long-term environmental fluctuations, respectively. Interested researchers are invited to build upon the preliminary findings.

scholarly journals Alterations in MurM, a Cell Wall Muropeptide Branching Enzyme, Increase High-Level Penicillin and Cephalosporin Resistance in Streptococcus pneumoniae

2001 ◽  
Vol 45 (8) ◽  
pp. 2393-2396 ◽  
Author(s):  
Anthony M. Smith ◽  
Keith P. Klugman
Keyword(s):  
Cell Wall ◽  
Stem Cell ◽  
Streptococcus Pneumoniae ◽  
Recipient Strain ◽  
Penicillin Binding Protein ◽  
Branching Enzyme ◽  
Cephalosporin Resistance ◽  
A Cell ◽  
High Level ◽  
Maximal Expression

ABSTRACT We report that alteration in MurM, an enzyme involved in the biosynthesis of branched-stem cell wall muropeptides, is required for maximal expression of penicillin and cefotaxime resistance in the pneumococcus. Hungarian isolate 3191 (penicillin MIC, 16 μg/ml; cefotaxime MIC, 4 μg/ml) was a source of donor DNA in transformation experiments. Penicillin-binding protein DNA was insufficient to transform recipient strain R6 to full resistance. Further transformation with altered murM DNA was required for full expression of donor penicillin and cefotaxime resistance.

scholarly journals Bactericidal Action of Gatifloxacin, Rifampin, and Isoniazid on Logarithmic- and Stationary-Phase Cultures of Mycobacterium tuberculosis

2005 ◽  
Vol 49 (2) ◽  
pp. 627-631 ◽  
Author(s):  
C. N. Paramasivan ◽  
S. Sulochana ◽  
G. Kubendiran ◽  
P. Venkatesan ◽  
D. A. Mitchison
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Stationary Phase ◽  
Bactericidal Activity ◽  
Bactericidal Action ◽  
Duration Of Treatment ◽  
Stationary Phase Culture ◽  
Treatment Regimens ◽  
Phase Culture ◽  
Bactericidal Activities ◽  
Strain H37rv

ABSTRACT The bactericidal activity of gatifloxacin, alone and in combination with isoniazid and rifampin, was studied on both exponential- and stationary-phase cultures of Mycobacterium tuberculosis strain H37Rv. On log-phase cultures, the bactericidal activity of gatifloxacin at 4 μg/ml was rapid and was very similar to that of isoniazid. At concentrations of 0.25 and 4 μg/ml, gatifloxacin enhanced the activity of isoniazid. Killing of the stationary-phase culture was biphasic. During the first 2 days, gatifloxacin at 4 μg/ml slightly increased the limited bactericidal activities of isoniazid and rifampin. However, no further additional bactericidal activity was found during further incubation with isoniazid alone or when gatifloxacin was added to either isoniazid or rifampin. This suggested that the stationary-phase culture contained a mixture of occasionally dividing bacilli that were killed during the first 2 days and true static persisters in the residual population that mimicked those in human lesions. In view of the failure of gatifloxacin to add to the sterilizing activity of isoniazid or rifampin during days 2 to 6 of exposure in the stationary-phase culture, it is unlikely to be a sterilizing drug that can be used to shorten the duration of treatment appreciably when it is added to present treatment regimens.

scholarly journals High-Level β-Lactam Resistance and Cell Wall Synthesis Catalyzed by the mecA Homologue of Staphylococcus sciuri Introduced into Staphylococcus aureus

2005 ◽  
Vol 187 (19) ◽  
pp. 6651-6658 ◽  
Author(s):  
Anatoly Severin ◽  
Shang Wei Wu ◽  
Keiko Tabei ◽  
Alexander Tomasz
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
High Performance ◽  
Protein Product ◽  
Spectrometric Analysis ◽  
Cell Wall Synthesis ◽  
Absolute Dependence ◽  
A Cell ◽  
High Concentrations ◽  
High Level

ABSTRACT A close homologue of mecA, the determinant of broad-spectrum β-lactam resistance in Staphylococcus aureus was recently identified as a native gene in the animal commensal species Staphylococcus sciuri. Introduction of the mecA homologue from a methicillin-resistant strain of S. sciuri into a susceptible strain of S. aureus caused an increase in drug resistance and allowed continued growth and cell wall synthesis of the bacteria in the presence of high concentrations of antibiotic. We determined the muropeptide composition of the S. sciuri cell wall by using a combination of high-performance liquid chromatography, mass spectrometric analysis, and Edman degradation. Several major differences between the cell walls of S. aureus and S. sciuri were noted. The pentapeptide branches in S. sciuri were composed of one alanine and four glycine residues in contrast to the pentaglycine units in S. aureus. The S. sciuri wall but not the wall of S. aureus contained tri- and tetrapeptide units, suggesting the presence of dd- and ld-carboxypeptidase activity. Most interestingly, S. aureus carrying the S. sciuri mecA and growing in methicillin-containing medium produced a cell wall typical of S. aureus and not S. sciuri, in spite of the fact that wall synthesis under these conditions had an absolute dependence on the heterologous S. sciuri gene product. The protein product of the S. sciuri mecA can efficiently participate in cell wall biosynthesis and build a cell wall using the cell wall precursors characteristic of the S. aureus host.

scholarly journals Reduced Lysis upon Growth of Lactococcus lactis on Galactose Is a Consequence of Decreased Binding of the Autolysin AcmA

2008 ◽  
Vol 74 (15) ◽  
pp. 4671-4679 ◽  
Author(s):  
Anton Steen ◽  
Girbe Buist ◽  
Naomi E. Kramer ◽  
Ruud Jalving ◽  
Germaine F. J. D. Benus ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasmodium Falciparum ◽  
Carbon Source ◽  
Fusion Protein ◽  
Stationary Phase ◽  
Lactococcus Lactis ◽  
Cell Walls ◽  
Trichloroacetic Acid ◽  
Binding Studies ◽  
Lipoteichoic Acids

ABSTRACT When Lactococcus lactis subsp. lactis IL1403 or L. lactis subsp. cremoris MG1363 is grown in a medium with galactose as the carbon source, the culture lyses to a lesser extent in stationary phase than when the bacteria are grown in a medium containing glucose. Expression of AcmA, the major autolysin of L. lactis, is not influenced by the carbon source. Binding studies with a fusion protein consisting of the MSA2 protein of Plasmodium falciparum and the C-terminal peptidoglycan-binding domain of AcmA revealed that cell walls of cells from both subspecies grown on galactose bind less AcmA than cell walls of cells grown on glucose. Cells grown on glucose or galactose and treated with trichloroacetic acid prior to AcmA binding bind similar amounts of AcmA. Analysis of the composition of the lipoteichoic acids (LTAs) of L. lactis IL1403 cells grown on glucose or galactose showed that the LTA composition is influenced by the carbon source: cells grown on galactose contain LTA with less galactose than cells grown on glucose. In conclusion, growth of L. lactis on galactose changes the LTA composition in the cell wall in such a way that less AcmA is able to bind to the peptidoglycan, resulting in a decrease in autolysis.

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