HETEROSIGMA AKASHIWO (RAPHIDOPHYCEAE) RESTING CELL FORMATION IN BATCH CULTURE: STRAIN IDENTITY VERSUS PHYSIOLOGICAL RESPONSE  1 , 2

2002 ◽  
Vol 38 (2) ◽  
pp. 304-317 ◽  
Author(s):  
Myung‐Soo Han ◽  
Young‐Pil Kim ◽  
Rose Ann Cattolico
Keyword(s):  
Batch Culture ◽  
Physiological Response ◽  
Cell Formation ◽  
Heterosigma Akashiwo ◽  
Resting Cell

scholarly journals MazEF-rifampicin interaction suggests a mechanism for rifampicin induced inhibition of persisters

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Cyrus Alexander ◽  
Ankeeta Guru ◽  
Pinkilata Pradhan ◽  
Sunanda Mallick ◽  
Nimai Charan Mahanandia ◽  
...  
Keyword(s):  
Batch Culture ◽  
Treatment Time ◽  
Cell Formation ◽  
Live Cells ◽  
Natural Phenomenon ◽  
Bacterial Strains ◽  
Bacterial Persistence ◽  
Death Phase ◽  
Resistant Strains ◽  
Persistent Bacteria

Abstract Background Persistence is a natural phenomenon whereby a subset of a population of isogenic bacteria either grow slow or become dormant conferring them with the ability to withstand various stresses including antibiotics. In a clinical setting bacterial persistence often leads to the recalcitrance of various infections increasing the treatment time and cost. Additionally, some studies also indicate that persistence can also pave way for the emergence of resistant strains. In a laboratory setting this persistent phenotype is enriched in nutritionally deprived environments. Consequently, in a batch culture the late stationary phase is enriched with persistent bacteria. The mechanism of persister cell formation and its regulation is not well understood. Toxin-antitoxin (TA) systems have been implicated to be responsible for bacterial persistence and rifampicin is used to treat highly persistent bacterial strains. The current study tries to explore a possible interaction between rifampicin and the MazEF TA system that furthers the former’s success rate in treating persistent bacteria. Results In the current study we found that the population of bacteria in the death phase of a batch culture consists of metabolically inactive live cells resembling persisters, which showed higher membrane depolarization as compared to the log phase bacteria. We also observed an increase in the expression of the MazEF TA modules in this phase. Since rifampicin is used to kill the persisters, we assessed the interaction of rifampicin with MazEF complex. We showed that rifampicin moderately interacts with MazEF complex with 1:1 stoichiometry. Conclusion Our study suggests that the interaction of rifampicin with MazEF complex might play an important role in inhibition of persisters.

scholarly journals MazEF-rifampicin interaction suggests a mechanism for rifampicin induced inhibition of persisters

2020 ◽  
Author(s):  
Cyrus Alexander ◽  
Ankeeta Guru ◽  
Pinkilata Pradhan ◽  
Sunanda Mallick ◽  
Nimai Charan Mahanandia ◽  
...  
Keyword(s):  
Batch Culture ◽  
Treatment Time ◽  
Cell Formation ◽  
Live Cells ◽  
Natural Phenomenon ◽  
Bacterial Strains ◽  
Bacterial Persistence ◽  
Death Phase ◽  
Resistant Strains ◽  
Persistent Bacteria

Abstract Background: Persistence is a natural phenomenon whereby a subset of a population of isogenic bacteria either grow slow or become dormant conferring them with the ability to withstand various stresses including antibiotics. In a clinical setting bacterial persistence often leads to the recalcitrance of various infections increasing the treatment time and cost. Additionally, some studies also indicate that persistence can also pave way for the emergence of resistant strains. In a laboratory setting this persistent phenotype is enriched in nutritionally deprived environments. Consequently, in a batch culture the late stationary phase is enriched with persistent bacteria. The mechanism of persister cell formation and its regulation is not well understood. Toxin-antitoxin (TA) systems have been implicated to be responsible for bacterial persistence and rifampicin is used to treat highly persistent bacterial strains. The current study tries to explore a possible interaction between rifampicin and the MazEF TA system that furthers the former’s success rate in treating persistent bacteria. Results: In the current study we found that the population of bacteria in the death phase of a batch culture consists of metabolically inactive live cells resembling persisters, which showed higher membrane depolarization as compared to the log phase bacteria. We also observed an increase in the expression of the MazEF TA modules in this phase. Since rifampicin is used to kill the persisters, we assessed the interaction of rifampicin with MazEF complex. We showed that rifampicin moderately interacts with MazEF complex with 1:1 stoichiometry.Conclusion: Our study suggests that the interaction of rifampicin with MazEF complex might play an important role in inhibition of persisters.

scholarly journals MazEF-rifampicin interaction suggests a mechanism for rifampicin induced inhibition of persisters

2020 ◽  
Author(s):  
Cyrus Alexander ◽  
Ankeeta Guru ◽  
Pinkilata Pradhan ◽  
Sunanda Mallick ◽  
Nimai Charan Mahanandia ◽  
...  
Keyword(s):  
Batch Culture ◽  
Treatment Time ◽  
Cell Formation ◽  
Live Cells ◽  
Natural Phenomenon ◽  
Bacterial Strains ◽  
Bacterial Persistence ◽  
Death Phase ◽  
Resistant Strains ◽  
Persistent Bacteria

Abstract Background: Persistence is a natural phenomenon whereby a subset of a population of isogenic bacteria either grow slow or become dormant conferring them with the ability to withstand various stresses including antibiotics. In a clinical setting bacterial persistence often leads to the recalcitrance of various infections increasing the treatment time and costs. Additionally, some studies also indicate that persistence can also pave way for the emergence of resistant strains. In a laboratory setting this persistent phenotype is enriched in nutritionally deprived environments. Consequently, in a batch culture the late stationary phase is enriched with persistent bacteria. The mechanism of persister cell formation and its regulation is not well understood. Toxin-antitoxins (TA) systems have been implicated to be responsible for bacterial persistence and rifampicin is used to treat highly persistent bacterial strains. The current study tries to explore a possible interaction between rifampicin and the MazEF TA system that furthers the former’s success rate in treating persistent bacteria. Results: In the current study we found that the population of bacteria in the death phase of a batch culture consists of metabolically inactive live cells resembling persisters, which showed higher membrane depolarization as compared to the log phase bacteria. We also observed an increase in the expression of the MazEF TA modules in this phase. Since rifampicin is used to kill the persisters, we assessed the interaction of rifampicin with MazEF complex. We showed that rifampicin moderately interacts with MazEF complex with 1:1 stoichiometry.Conclusion: Our study suggests that the interaction of rifampicin with MazEF complex might play an important role in inhibition of persisters.

scholarly journals Developmental transcriptome of resting cell formation in Mycobacterium smegmatis

BMC Genomics ◽  
2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Mu-Lu Wu ◽  
Martin Gengenbacher ◽  
Jade C. S. Chung ◽  
Swaine Lin Chen ◽  
Hans-Joachim Mollenkopf ◽  
...  
Keyword(s):  
Mycobacterium Smegmatis ◽  
Cell Formation ◽  
Resting Cell

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

Sign in / Sign up

Export Citation Format

Share Document