Acetate excretion by a methanotroph, Methylocaldum marinum S8, under aerobic conditions

Author(s):  
Mio Takeuchi ◽  
Hideyoshi Yoshioka

ABSTRACT Methane-oxidizing bacteria (methanotrophs) often coexist with methylotrophs that utilize methanol excreted by methanotrophs. Recently, we found that a facultative methylotroph, Methyloceanibacter caenitepidi Gela4T, possibly utilizes acetate rather than methanol in the coculture with a methanotroph, Methylocaldum marinum S8. Here, we examined the effects of oxygen concentrations on growth of and acetate excretion by M. marinum S8 in pure culture and the coculture with M. caenitepidi Gela4T. M. marinum S8 excreted acetate during the exponential growth phase not only under microaerobic (O2 concentrations of 3.5%-6%) but also under aerobic (O2 concentrations of 20%-31%) conditions. RNA-Seq analyses of M. marinum S8 cells grown under aerobic conditions suggested that phosphoketolase and acetate kinase were candidate genes involved in acetate production. Nonmethylotrophic bacteria, Cupriavidus necator NBRC 102504, could grow when cocultured with M. marinum S8, also supporting the existence of methanol-independent cross-feeding from M. marinum S8 under aerobic conditions.

2005 ◽  
Vol 41 (1) ◽  
pp. 40-43
Author(s):  
A. M. Veselovskii ◽  
A. Z. Metlitskaya ◽  
V. A. Lipasova ◽  
I. A. Bass ◽  
I. A. Khmel

Author(s):  
Jack Merrin

1AbstractAn automated statistical and error analysis of 45 countries or regions with more than 1000 cases of COVID-19 as of March 28, 2020, has been performed. This study reveals differences in the rate of disease spreading rate over time in different countries. This survey observes that most countries undergo a beginning exponential growth phase, which transitions into a power-law phase, as recently suggested by Ziff and Ziff. Tracking indicators of growth, such as the power-law exponent, are a good indication of the relative danger different countries are in and show when social measures are effective towards slowing the spread. The data compiled here are usefully synthesizing a global picture, identifying country to country variation in spreading, and identifying countries most at risk. This analysis may factor into how best to track the effectiveness of social distancing policies and quarantines in real-time as data is updated each day.


1979 ◽  
Vol 182 (2) ◽  
pp. 407-412 ◽  
Author(s):  
R J Allen ◽  
G K Scott

Isolated outer membranes and outer-membrane extracts from Escherichia coli ML308-225 in the early-exponential growth phase contain more protein than do corresponding preparations from late-exponential- or stationary-phase bacteria. Isotope-dilution experiments show that this is due to a loss of protein from the membrane during the exponential growth phase. Inhibition of bacterial growth and protein synthesis stabilizes the outer-membrane-protein concentration. Protein synthesis in the absence of bacterial growth results in higher concentrations of protein in the outer membrane.


1973 ◽  
Vol 13 (6) ◽  
pp. 523-528 ◽  
Author(s):  
E. M. Shulgovskaya ◽  
I. I. Ivanova ◽  
G. G. Sotnicov

2009 ◽  
Vol 191 (8) ◽  
pp. 2776-2782 ◽  
Author(s):  
Shin Kurihara ◽  
Yuichi Tsuboi ◽  
Shinpei Oda ◽  
Hyeon Guk Kim ◽  
Hidehiko Kumagai ◽  
...  

ABSTRACT The Puu pathway is a putrescine utilization pathway involving gamma-glutamyl intermediates. The genes encoding the enzymes of the Puu pathway form a gene cluster, the puu gene cluster, and puuP is one of the genes in this cluster. In Escherichia coli, three putrescine importers, PotFGHI, PotABCD, and PotE, were discovered in the 1990s and have been studied; however, PuuP had not been discovered previously. This paper shows that PuuP is a novel putrescine importer whose kinetic parameters are equivalent to those of the polyamine importers discovered previously. A puuP + strain absorbed up to 5 mM putrescine from the medium, but a ΔpuuP strain did not. E. coli strain MA261 has been used in previous studies of polyamine transporters, but PuuP had not been identified previously. It was revealed that the puuP gene of MA261 was inactivated by a point mutation. When E. coli was grown on minimal medium supplemented with putrescine as the sole carbon or nitrogen source, only PuuP among the polyamine importers was required. puuP was expressed strongly when putrescine was added to the medium or when the puuR gene, which encodes a putative repressor, was deleted. When E. coli was grown in M9-tryptone medium, PuuP was expressed mainly in the exponential growth phase, and PotFGHI was expressed independently of the growth phase.


BMC Genomics ◽  
2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Yoo-Bok Cho ◽  
Eun Ju Lee ◽  
Suhyung Cho ◽  
Tae Yong Kim ◽  
Jin Hwan Park ◽  
...  

2012 ◽  
Vol 76 (3) ◽  
pp. 628-631 ◽  
Author(s):  
Keisuke ITO ◽  
Aya HIKIDA ◽  
Sayuri KITAGAWA ◽  
Takumi MISAKA ◽  
Keiko ABE ◽  
...  

1982 ◽  
Vol 60 (7) ◽  
pp. 1673-1675 ◽  
Author(s):  
M. Belosevic ◽  
G. M. Faubert ◽  
N. A. Croll ◽  
J. D. MacLean

The trophozoites of Giardia lamblia were gradually adapted to grow in both autoclaved and filtered Diamond's TYI-S-33 culture medium. Comparative growth studies indicated that the growth of organisms was significantly higher in filtered TYI-S-33 medium. In both types of media the exponential growth phase occurred between 48 and 96 h postinoculation. The mean number of trophozoites at 96 h was 1.94 × 105 and 4.82 × 105 cells/mL for autoclaved and filtered media, respectively. The generation times for the exponential growth phase were 9.66 h. for autoclaved and 7.69 h for filtered medium. The percentage of dead trophozoites was similar in both media and was 14% for the first 8 days postinoculation.


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