scholarly journals Early stationary phase culture supernatant accelerates growth of sputum cultures collected after initiation of anti-tuberculosis treatment

2014 ◽  
Vol 20 (7) ◽  
pp. O418-O420 ◽  
Author(s):  
E. Kolwijck ◽  
S.O. Friedrich ◽  
M.N. Karinja ◽  
J. van Ingen ◽  
R.M. Warren ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Culture Supernatant ◽  
Tuberculosis Treatment ◽  
Early Stationary Phase ◽  
Stationary Phase Culture ◽  
Phase Culture

scholarly journals Growth-Phase-Dependent Expression of the Cyclopeptide Antibiotic Microcin J25

2001 ◽  
Vol 183 (5) ◽  
pp. 1755-1764 ◽  
Author(s):  
Marı́a J. Chiuchiolo ◽  
Mónica A. Delgado ◽  
Ricardo N. Farı́as ◽  
Raúl A. Salomón
Keyword(s):  
Stationary Phase ◽  
Growth Phase ◽  
High Cell Density ◽  
Integration Host Factor ◽  
Early Stationary Phase ◽  
Stationary Phase Culture ◽  
Global Regulators ◽  
Phase Culture ◽  
Microcin J25 ◽  
Growth Induction

ABSTRACT Microcin J25 is a 2,107-Da, plasmid-encoded, cyclopeptide antibiotic produced by Escherichia coli. We have isolatedlacZ fusions to mcjA (encoding the 58-amino-acid microcin precursor) and mcjB andmcjC (which are required for microcin maturation), and the regulation of these fusions was used to identify factors that control the expression of these genes. The mcjA gene was found to be dramatically induced as cells entered the stationary phase. Expression of mcjA could be induced by resuspending uninduced exponential-phase cells in spent supernatant obtained from an early-stationary-phase culture. Induction of mcjAexpression was not dependent on high cell density, pH changes, anaerobiosis, or the buildup of some inducer. A starvation for carbon and inorganic phosphate induced mcjA expression, while under nitrogen limitation there was no induction at all. These results taken together suggest that stationary-phase induction ofmcjA is triggered by nutrient depletion. ThemcjB and mcjC genes were also regulated by the growth phase of the culture, but in contrast to mcjA, they showed substantial expression already during exponential growth. Induction of the microcin genes was demonstrated to be independent of RpoS, the cyclic AMP-Crp complex, OmpR, and H-NS. Instead, we found that the growth-phase-dependent expression of mcjA,mcjB, and mcjC may be explained by the concerted action of the positively acting transition state regulators ppGpp, Lrp, and integration host factor. Measurements of microcin J25 production by strains defective in these global regulators showed a good correlation with the reduced expression of the fusions in such mutant backgrounds.

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.

Identification of immunoreactive secretory proteins from the stationary phase culture of Burkholderia pseudomallei

2010 ◽  
Vol 32 (2) ◽  
pp. 310-320 ◽  
Author(s):  
Kumutha Malar Vellasamy ◽  
Vanitha Mariappan ◽  
Onn H. Hashim ◽  
Jamuna Vadivelu
Keyword(s):  
Stationary Phase ◽  
Burkholderia Pseudomallei ◽  
Secretory Proteins ◽  
Stationary Phase Culture ◽  
Phase Culture

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 Vibrio cholerae Hemagglutinin/Protease Inactivates CTXφ

1998 ◽  
Vol 66 (9) ◽  
pp. 4025-4029 ◽  
Author(s):  
Harvey H. Kimsey ◽  
Matthew K. Waldor
Keyword(s):  
Stationary Phase ◽  
Vibrio Cholerae ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Natural Environments ◽  
Phase Growth ◽  
Stationary Phase Culture ◽  
Phase Culture ◽  
El Tor ◽  
Culture Supernatants

ABSTRACT Pathogenic strains of Vibrio cholerae are lysogens of the filamentous phage CTXφ, which carries the genes for cholera toxin (ctxAB). We found that the titers of infective CTXφ in culture supernatants of El Tor CTXφ lysogens increased rapidly during exponential growth but dropped to undetectable levels late in stationary-phase growth. When CTXφ transducing particles were mixed with stationary-phase culture supernatants of El Tor strains, CTXφ infectivity was destroyed. Our data indicate that this growth phase-regulated factor, designated CDF (CTXφ-destroying factor), is the secreted hemagglutinin/protease (HA/P) of V. cholerae. A strain containing a disrupted hap gene, which encodes HA/P of V. cholerae, did not produce CDF activity in culture supernatants. Introduction of the HA/P-expressing plasmid pCH2 restored CDF activity. Also, CDF activity in culture supernatants of a variety of pathogenic V. cholerae isolates varied widely but correlated with the levels of secreted HA/P, as measured by immunoblotting with anti-HA/P antibody. CDF was purified from V. cholerae culture supernatants and shown to contain a 45-kDa polypeptide which bound anti-HA/P antibodies and which comigrated with HA/P in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The production of high levels of secreted HA/P by certain V. cholerae strains may be a factor in preventing CTXφ reinfection in natural environments and in the human host.

scholarly journals Spent Culture Supernatant of Mycobacterium tuberculosis H37Ra Improves Viability of Aged Cultures of This Strain and Allows Small Inocula To Initiate Growth

1999 ◽  
Vol 181 (24) ◽  
pp. 7626-7628 ◽  
Author(s):  
Zhonghe Sun ◽  
Ying Zhang
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Stationary Phase ◽  
Liquid Culture ◽  
Culture Supernatant ◽  
Early Stationary Phase ◽  
Heat Stable ◽  
Acid Labile

ABSTRACT Spent culture supernatant from early-stationary-phaseMycobacterium tuberculosis H37Ra cultures increased the viability of bacilli from aged cultures of this strain and allowed small inocula to initiate growth in liquid culture. The resuscitation factor was acid labile and heat stable, with a mass of less than 1,375 Da.

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