One of the major environmental concerns over genetically modified (GM) crops relates to transgene movement into wild relatives. The pattern of hybridization ultimately affects the scale and rapidity of ecological change and the feasibility of containment. A new procedure for quantifying hybrid formation over large areas is described. Remote sensing was used to identify possible sites of sympatry between Brassica napus and its progenitor species across 15 000 km2 of south-east England in 1998. Two sympatric populations with B. rapa and one with B. oleracea were found over the entire survey area. Every newly recruited plant in these populations in 1999 was screened for hybrid status using flow cytometry and molecular analyses. One hybrid was observed from the 505 plants screened in the B. rapa populations but none of the nine B. oleracea recruits were hybrids. Measures to minimize gene flow are suggested, and a procedure for the post-release evaluation and containment of GM cultivars is proposed.
The universally distributed heat-shock proteins (HSPs) are divided into classes based on molecular weight and sequence conservation. The members of at least two of these classes, the HSP60s and the HSP70s, have chaperone activity. Most HSP60s and many HSP70s feature a striking motif at or near the carboxyl terminus which consists of a string of repeated glycine and methionine residues. We have altered the groEL gene (encoding the essential Escherichia coli HSP60 chaperonin) so that the protein produced lacks its 16 final (including nine gly, and five met) residues. This truncated product behaves like the intact protein in several in vitro tests, the only discernible difference between the two proteins being in the rate at which ATP is hydrolysed. GroELtr can substitute for GroEL in vivo although cells dependent for survival on the truncated protein survive slightly less well during the stationary phase of growth. Elevated levels of the wild-type protein can suppress a number of temperature-sensitive mutations; the truncated protein lacks this ability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.