Recently, transgenic crops have been considered as possible donors of transgenes that could be taken up by micro-organisms under appropriate conditions. In an in vitro rumen simulation system, effects of ampicillin on microbial communities growing either on rumen contents with transgenic maize carrying a gene that confers resistance to ampicillin or its isogenic counterpart as substrates were examined continuously over 13 d. Rate of production of SCFA was measured to determine functional changes in the rumen model and single-strand conformational polymorphism was used to detect alterations in structure of the microbial community. Rumen contents treated with ampicillin displayed a marked decrease in the rate of production of SCFA and diversity of the microbial community was reduced severely. In the presence of transgenic maize, however, the patterns of change of rumen micro-organisms and their metabolic profiles were different from that of rumen fluid incorporating maize bred conventionally. Recovery of propionate production was observed both in the rumen fluid fed transgenic and conventional maize after a delay of several days but recovery occurred earlier in fermenters fed transgenic maize. Alterations in the microbial population structures resulting from the ampicillin challenge were not reversed during the experimental run although there was evidence of adaptation of the microbial communities over time in the presence of the antibiotic, showing that populations with different microbial structures could resume a pre-challenge metabolic profile following the introduction of ampicillin, irrespective of the source of the plant material in the growth medium.

Scholars have long understood that linkages between the identities of actors and the design of their actions in interaction constitute one of the central mechanisms by which social patterns are produced. Although a range of empirical approaches has successfully grounded claims regarding the significance of various forms or types of identity (gender, sex, race, ethnicity, class, familial status, etc.) in almost every form of social organization, these analyses have mostly focused on aggregated populations, aggregated interactions, or historical periods that have been (in different ways) abstracted from the particulars of singular episodes of interaction. By contrast, establishing the mechanisms by which a specific identity is made relevant and consequential in any particular episode of interaction has remained much more elusive. This article develops a range of general analytic resources for explicating how participants in an interaction can make relevant and consequential specific identities in particular courses of action. It then illustrates the use of these analytic resources by examining a phone call between two friends, one of whom relevantly embodies “grandparent” as an identity. The conclusion offers observations prompted by this analysis regarding basic contingencies that characterize self-other relationships, and the role of generic grammatical resources in establishing specific identities and intimate relationships.