Response of Azospirillum brasilense Cd to sodium chloride stress.

Growth of Azospirillum brasilense Cd in the presence of different NaCl concentrations showed that it tolerates up to 200 mM NaCl in the medium, without appreciable decline in growth rate. At 300 mM NaCl, a decrease of 66% in growth was observed at 24 h of culture. At 48 h of culture, bacteria in the presence of 300 mM NaCl reached the maximum optical density value that was attained at 12 h by control cultures.

2,4-Dichlorophenoxyacetic acid affects the attachment of Azospirillum brasilense Cd to maize roots.

2.4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide widely applied to forage, grain and cereals. We previously determined that 1 mM 2,4-D diminished cell growth and cellular activity of Azospirillum brasilense Cd.

Characterization of 2,4-dichlorophenoxyacetic acid transport and its relationship with polyamines in Azospirillum brasilense.

We have previously shown that 2,4-dichlorophenoxyacetic acid (2,4-D) inhibits Azospirillum brasilense growth, the synthesis of DNA, RNA and proteins. These toxic effects are prevented when polyamines are added to the culture medium. The purposes of our research were to determine the effects of the herbicide on the number of viable Azospirillum brasilense cells, characterize the 2,4-D transport system and to study the effects of polyamines upon the latter in this microorganism.

2,4-Dichlorophenoxyacetic acid influx is mediated by an active transport system in Chinese hamster ovary cells.

The influx of 2,4-dichlorophenoxyacetic acid (2,4-D) into Chinese hamster ovary (CHO) cells was studied. The cells mainly took up but did not metabolize the undissociated form of the herbicide. The uptake of 2,4-D was carried out against a concentration gradient and was inhibited by sodium azide and dinitrophenol.

Effects of 2,4-dichlorophenoxyacetic acid on polyamine transport and metabolism in Azospirillum brasilense Cd.

We had previously demonstrated that 1 mM 2,4-D inhibited cell growth, nucleic acid synthesis and protein synthesis (at the ribosomal level) of Azospirillum brasilense. These alterations were prevented by the presence of polyamines in the culture medium. On the other hand, polyamines did not affect the 2,4-D uptake.