Ribosome Modulation Factor: Stationary Growth Phase-Specific Inhibitor of Ribosome Functions from Escherichia coli

1995 ◽  
Vol 214 (2) ◽  
pp. 410-417 ◽  
Author(s):  
A. Wada ◽  
K. Igarashi ◽  
S. Yoshimura ◽  
S. Aimoto ◽  
A. Ishihama
2002 ◽  
Vol 184 (15) ◽  
pp. 4304-4307 ◽  
Author(s):  
Eric Soupene ◽  
Natalie King ◽  
Haidy Lee ◽  
Sydney Kustu

ABSTRACT Transcription of an aqpZ-lac fusion in a single copy on the Escherichia coli chromosome increased as cells entered the stationary growth phase. This was true in a variety of media, and increased transcription in enriched medium required the RpoS sigma factor. Expression of the aqpZ-lac fusion was not affected by up- or downshifts in osmolality. Disruption of aqpZ had no detectable adverse effects.


2009 ◽  
Vol 191 (9) ◽  
pp. 3177-3182 ◽  
Author(s):  
Ilana Kolodkin-Gal ◽  
Hanna Engelberg-Kulka

ABSTRACT Escherichia coli mazEF is a toxin-antitoxin gene module that mediates cell death during exponential-phase cellular growth through either reactive oxygen species (ROS)-dependent or ROS-independent pathways. Here, we found that the stationary-phase sigma factor σS was responsible for the resistance to mazEF-mediated cell death during stationary growth phase. Deletion of rpoS, the gene encoding σS from the bacterial chromosome, permitted mazEF-mediated cell death during stationary growth phase.


2008 ◽  
Vol 74 (15) ◽  
pp. 4847-4852 ◽  
Author(s):  
Anastasia Matthies ◽  
Thomas Clavel ◽  
Michael Gütschow ◽  
Wolfram Engst ◽  
Dirk Haller ◽  
...  

ABSTRACT The metabolism of isoflavones by gut bacteria plays a key role in the availability and bioactivation of these compounds in the intestine. Daidzein and genistein are the most common dietary soy isoflavones. While daidzein conversion yielding equol has been known for some time, the corresponding formation of 5-hydroxy-equol from genistein has not been reported previously. We isolated a strictly anaerobic bacterium (Mt1B8) from the mouse intestine which converted daidzein via dihydrodaidzein to equol as well as genistein via dihydrogenistein to 5-hydroxy-equol. Strain Mt1B8 was a gram-positive, rod-shaped bacterium identified as a member of the Coriobacteriaceae. Strain Mt1B8 also transformed dihydrodaidzein and dihydrogenistein to equol and 5-hydroxy-equol, respectively. The conversion of daidzein, genistein, dihydrodaidzein, and dihydrogenistein in the stationary growth phase depended on preincubation with the corresponding isoflavonoid, indicating enzyme induction. Moreover, dihydrogenistein was transformed even more rapidly in the stationary phase when strain Mt1B8 was grown on either genistein or daidzein. Growing the cells on daidzein also enabled conversion of genistein. This suggests that the same enzymes are involved in the conversion of the two isoflavones.


2010 ◽  
Vol 8 (1) ◽  
pp. 51 ◽  
Author(s):  
Niurka Meneses ◽  
Guillermo Mendoza-Hernández ◽  
Sergio Encarnación

2005 ◽  
Vol 187 (6) ◽  
pp. 1951-1958 ◽  
Author(s):  
Toshiko Aiso ◽  
Hideji Yoshida ◽  
Akira Wada ◽  
Reiko Ohki

ABSTRACT The expression of ribosome modulation factor (RMF) is induced during stationary phase in Escherichia coli. RMF participates in the dimerization of 70S ribosomes to form the 100S ribosome, which is the translationally inactive form of the ribosome. To elucidate the involvement of the control of mRNA stability in growth-phase-specific rmf expression, we investigated rmf mRNA stability in stationary-phase cells and cells inoculated into fresh medium. The rmf mRNA was found to have an extremely long half-life during stationary phase, whereas destabilization of this mRNA took place after the culture was inoculated into fresh medium. RMF and 100S ribosomes disappeared from cells 1 min after inoculation. In addition to control by ppGpp-dependent transcription, these results indicate that the modulation of rmf mRNA stability is also involved in the regulation of growth-phase-specific rmf expression. Unexpectedly, the postinoculation degradation of rmf mRNA was suppressed by the addition of rifampin, suggesting that de novo RNA synthesis is necessary for degradation. This degradation was also suppressed in both a poly(A) polymerase-deficient and an rne-131 mutant strain. We cloned and sequenced the 3′-proximal regions of rmf mRNAs and found that most of these 3′ ends terminated at the ρ-independent terminator with the addition of a one- to five-A oligo(A) tail in either stationary-phase or inoculated cells. No difference was observed in the length of the poly(A) tail between stationary-phase and inoculated cells. These results suggest that a certain postinoculation-specific regulatory factor participates in the destabilization of rmf mRNA and is dependent on polyadenylation.


PROTEOMICS ◽  
2018 ◽  
Vol 18 (14) ◽  
pp. 1800116 ◽  
Author(s):  
Micaela Cerletti ◽  
María Ines Giménez ◽  
Christian Tröetschel ◽  
Celeste D’ Alessandro ◽  
Ansgar Poetsch ◽  
...  

1979 ◽  
Vol 42 (11) ◽  
pp. 848-851 ◽  
Author(s):  
Y. PARK ◽  
E. M. MIKOLAJCIK

Growth and alpha toxin production by a strain of Clostridium perfringens was determined in Thioglycollate medium, beef broth with ground beef, and beef broth with ground beef and soy protein. Incubation temperatures ranged from 15 to 50 C. In Thioglycollate medium, maximum alpha toxin production occurred at 35 C and was 40 times greater than that observed at 45 C. However, generation time and maximum population were approximately the same at 35 and 45 C. At 15 C, a two log cycle reduction in viable counts occurred within 6 h. Irrespective of incubation temperature, alpha toxin levels in Thioglycollate medium declined as the incubation period was extended beyond the stationary growth phase. In the beef broth with ground beef system which was studied at 35 C only, the organism grew slower and produced less toxin than in Thioglycollate medium. The amount of alpha toxin detected was influenced to a greater extent by the incubation time and temperature, the holding time beyond the stationary growth phase, and the growth medium than by the population level of C. perfringens.


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