Efficient conjugal transfer of inc R-plasmids at high salt concentration in the mating media.

Abstract

There is an optimal salt concentration of mating in the conjugal transfer of an R plasmid, and incompatibility (Inc) group C R-plasmids are characteristic in that they demand high salt concentration such as 0.34M or more in the efficient R-transfer.Both sodium and potassium salt are effective but divalent cation (Mg) are not.Many pili-like structure of Escherichia coli carrying an Inc C plasmid Rms 417 were observed on an L agar plate which contained 0.34M salt, but few in the absence of salt. Therefore, the pili could be considered sex pili that E. coli R+ produced in the presence of a moderate amount of monovalent salt.

Physicochemical Factors That Favor Conjugation of an Antibiotic Resistant Plasmid in Non-growing Bacterial Cultures in the Absence and Presence of Antibiotics

“…A few authors have reported increased conjugation with increasing salinity in the presence of growth media (Singleton, 1983 , 1984 ; Hayashi et al, 1988 ; Beuls et al, 2012 ). However, all of these studies examined conjugation at much higher salinities than we examined.…”

“…Rarely are the same methods used by investigators to assess conjugation. For example, some studies have chosen to shake cultures (Zhang et al, 2013 ; Händel et al, 2015 ), while other studies have chosen not to shake cultures (Hayashi et al, 1988 ; Fernandez-Astorga et al, 1992 ; Muela et al, 1994 ; Beuls et al, 2012 ; Sandegren et al, 2012 ; Lopatkin et al, 2016 ). Some studies have examined conjugation in liquid cultures (Barr et al, 1986 ; Fernandez-Astorga et al, 1992 ; Sandegren et al, 2012 ; Zhang et al, 2013 ; Schuurmans et al, 2014 ; Händel et al, 2015 ; Lopatkin et al, 2016 ), while others have examined conjugation using the filter plate method (Kim et al, 2014 ; Jutkina et al, 2016 , 2018 ; Moller et al, 2017 ).…”

“…Some studies have examined conjugation in liquid cultures (Barr et al, 1986 ; Fernandez-Astorga et al, 1992 ; Sandegren et al, 2012 ; Zhang et al, 2013 ; Schuurmans et al, 2014 ; Händel et al, 2015 ; Lopatkin et al, 2016 ), while others have examined conjugation using the filter plate method (Kim et al, 2014 ; Jutkina et al, 2016 , 2018 ; Moller et al, 2017 ). Many studies have examined conjugation at 37°C (Khalil and Gealt, 1987 ; Hayashi et al, 1988 ; Fernandez-Astorga et al, 1992 ; Sandegren et al, 2012 ; Zhang et al, 2013 ; Moller et al, 2017 ), while many other investigators have utilized other temperatures for their experiments (Fernandez-Astorga et al, 1992 ; Muela et al, 1994 ; Beuls et al, 2012 ; Jutkina et al, 2016 ; Lopatkin et al, 2016 ; p. 74; Jutkina et al, 2018 ).…”

“…One area of methodological agreement appears to be the use of growing bacterial cultures in conjugation experiments. There is good evidence that conjugation increases with bacterial growth (Muela et al, 1994 ; Schuurmans et al, 2014 ; Händel et al, 2015 ; Lopatkin et al, 2016 ) and the vast majority of conjugation studies are conducted on growing bacterial populations or populations exposed to growth media during conjugation (e.g., Barr et al, 1986 ; Hayashi et al, 1988 ; Fernandez-Astorga et al, 1992 ; Beaber et al, 2004 ; Beuls et al, 2012 ; Sandegren et al, 2012 ; Zhang et al, 2013 ; Kim et al, 2014 ; Schuurmans et al, 2014 ; Händel et al, 2015 ; Jutkina et al, 2016 , 2018 ; Lopatkin et al, 2016 ; Matsumoto et al, 2016 ; Moller et al, 2017 ). However, just because conjugation has been shown to increase with bacterial growth does not mean that it does not occur in non-growing bacteria.…”

Frequency of drug resistance in Vibrio spp. in Japan

“…There is currently some interest in the trans-posability of heavy metal ion and Ap resistance genes in Enterobacteriaceae (Summers et al 1978;Bukhari et al 1977). Ap and heavy metal resistance may be developed by over use of drugs and by environmental pollution (Hayashi et al 1982b(Hayashi et al , 1988Aoki 1985). Various soil pollutants may accumulate in fish body tissues, which are then used for human consumption.…”