scholarly journals Isolation and Characterization of thenikR Gene Encoding a Nickel-Responsive Regulator inEscherichia coli

1999 ◽  
Vol 181 (2) ◽  
pp. 670-674 ◽  
Author(s):  
Karinne De Pina ◽  
Valerie Desjardin ◽  
Marie-Andree Mandrand-Berthelot ◽  
Gerard Giordano ◽  
Long-Fei Wu

ABSTRACT Expression of the nickel-specific transport system encoded by theEscherichia coli nikABCDE operon is repressed by a high concentration of nickel. By using random transposon Tn10 insertion, we isolated mutants in which expression of the nik operon became constitutive with respect to nickel. We have identified the corresponding nikR gene which encodes a nickel-responsive regulator. Expression of nikRwas partially controlled by Fnr through transcription from thenikA promoter region. In addition, a specific transcription start site for the constitutive expression of nikR was found 51 bp upstream of the nikR gene.

2001 ◽  
Vol 3 (5) ◽  
pp. 485-494 ◽  
Author(s):  
Yu Xia ◽  
Tsunao Saitoh ◽  
Kenji Uéda ◽  
Seigo Tanaka ◽  
Xiaohua Chen ◽  
...  

1999 ◽  
Vol 337 (2) ◽  
pp. 329-335 ◽  
Author(s):  
José A. ORTIZ ◽  
Judith MALLOLAS ◽  
Carine NICOT ◽  
Josep BOFARULL ◽  
Joan C. RODRÍGUEZ ◽  
...  

Low expression of the mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase gene during development correlates with an unusually low hepatic ketogenic capacity and lack of hyperketonaemia in piglets. Here we report the isolation and characterization of the 5´ end of the pig mitochondrial HMG-CoA synthase gene. The 581 bp region proximal to the transcription start site permits transcription of a reporter gene, confirming the function of the promoter. The pig mitochondrial HMG-CoA synthase promoter is trans-activated by the peroxisomal proliferator-activated receptor (PPAR), and a functional response element for PPAR (PPRE) has been localized in the promoter region. Pig PPRE is constituted by an imperfect direct repeat (DR-1) and a downstream sequence, both of which are needed to confer PPAR-sensitivity to a thymidine kinase promoter and to form complexes with PPAR·retinoid X receptor heterodimers. A role of PPAR trans-activation in starvation-associated induction of gene expression is suggested.


Gene ◽  
1996 ◽  
Vol 174 (2) ◽  
pp. 221-224 ◽  
Author(s):  
Travis Henry ◽  
Brian Kliewer ◽  
Robert Palmatier ◽  
Joseph S. Ulphani ◽  
Joe D. Beckmann

2021 ◽  
pp. 004051752110154
Author(s):  
Zhihui Qin ◽  
Shuyuan Zhao ◽  
Liu Liu ◽  
Zhaohe Shi ◽  
Longdi Cheng ◽  
...  

Degumming is the dominant method for insolating lignocellulosic fibers in textile applications. Traditional alkaline degumming (TAL), as a common method, requires a high-concentration alkali and has been a severe challenge to the environment. In the research reported here, the possibility of innovative jute degumming by organic solvents 1-2 propylene glycol and a combination of additive green oxygen (GO-OS) was studied. The results revealed that fibers could be extracted by this system (under condition of 0.9% GO-OS, 180°C, 120 min), and obtained fibers with higher breaking tenacity (7.1 cN/dtex), yield (65.7%), breaking elongation (2.87%) and residual gum (11.7%), which all meet the requirement of the relevant Chinese Textile National Standards. Notably, the required reaction time (120 min) of the GO-OS system was 180 min shorter than that of the TAL method. Furthermore, the modifications introduced by the degumming effect on physicochemical aspects were characterized and confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. This study provides a promising degumming method for separating jute lignocellulose without acid and alkali consumption.


2019 ◽  
Vol 8 (2) ◽  
pp. 43-48
Author(s):  
Halima Aurass Bahloul ◽  
Hadadji Miloud ◽  
Mebrouk Kihal

Bifidobacteria represent the largest group of human intes nal bacteria. They have an important place in human health and represent the dominant group of micro ora. For this reason, they are key members of the human gut microbiota, particularly during the first one to two years following birth. The aim of this study was to test the sensibility of Bifidobacterium isolated from some strains at different concentrations of salinity and high concentration of bile as a criterion to select probiotic strains. Following the behavior of strains of Bifidobacteria isolated from different ecosystems was considered in order to develop the therapeu c aliment food . Samples from newborn infants aged 3 months, bee intestine, fermented commercial milk and yoghurt of bifidus containing Bifidobacteria was used and the isolated strains belonged to -breve and -longum species. The results of resisitance of our species of Bifidobacteria demonstrated a total inibition of croissance at 5.5% of NaCl but in 5% media of NaCl we observed a moderate croissance at di erent me of kinetics croissance .


Gene ◽  
1990 ◽  
Vol 91 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Judit Castella-Escola ◽  
David M. Ojcius ◽  
Philippe LeBoulch ◽  
Virginie Joulin ◽  
Yves Blouquit ◽  
...  

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 108
Author(s):  
Wang Liu ◽  
Xiaowei Zheng ◽  
Xin Dai ◽  
Zhenfeng Zhang ◽  
Wenyan Zhang ◽  
...  

Viruses are far more abundant than cellular microorganisms in the marine ecosystem. However, very few viruses have so far been isolated from marine sediments, especially hydrothermal vent sediments, hindering the understanding of the biology and ecological functions of these tiny organisms. Here, we report the isolation and characterization of a temperate bacteriophage, named PVJ1, which infects Psychrobacillus from a hydrothermal vent field in Okinawa Trough. PVJ1 belongs to the Myoviridae family of the order Caudovirales. The tailed phage possesses a 53,187 bp linear dsDNA genome, with 84 ORFs encoding structural proteins, genome replication, host lysis, etc. in a modular pattern. The phage genome is integrated into the host chromosome near the 3′-end of deoD, a gene encoding purine nucleoside phosphorylase (PNP). The phage integration does not appear to disrupt the function of PNP. The phage DNA is packaged by the headful mechanism. Release of PVJ1 from the host cell was drastically enhanced by treatment with mitomycin C. Phages encoding an MCP sharing significant similarity (≥70% identical amino acids) with that of PVJ1 are widespread in diverse environments, including marine and freshwater sediments, soils, artificial ecosystems, and animal intestines, and primarily infect Firmicutes. These results are valuable to the understanding of the lifestyle and host interactions of bacterial viruses at the bottom of the ocean.


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