Open AccessHeterologous expression of Escherichia coli porin genes in Salmonella typhi Ty2: regulation by medium osmolarity, temperature and oxygen availability
Author(s) -
Contreras Inés,
Munoz Lorena,
Toro Cecilia S.,
Mora Guido C.
Publication year - 1995
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1995.tb07869.x
Subject(s) - porin , salmonella typhi , escherichia coli , microbiology and biotechnology , osmotic concentration , heterologous , salmonella , heterologous expression , biology , enterobacteriaceae , bacteria , gene , chemistry , genetics , bacterial outer membrane , biochemistry , recombinant dna
Electrophoretic analysis of outer membrane proteins showed that Salmonella typhi OmpC expression is not reciprocally regulated relative to OmpF as described for Escherichia coli and S. typhimurium . When bacteria were grown in minimal media, both OmpC and OmpF were repressed as the osmolarity increased. However, in Luria broth, expression of OmpC was slightly induced by osmolarity up to 0.3 osmM. Plasmids bearing E. coli ompC‐lacZ or ompF‐lacZ gene fusions were studied for their expression in S. typhi and E. coli . Under anaerobic growth conditions, expression of ompC‐lacZ in S. typhi was maximal at 0.16 osmM, while in E. coli expression was maximal at 0.7 osmM. ompF‐lacZ expression was similarly repressed by medium osmolarity and anaerobiosis in both species. In contrast, a drastic difference in the regulation of OmpF by temperature was observed; at 37 °C ompF‐lacZ expression was repressed in E. coli . while in S. typhi it was induced.