Recurrent mutualism breakdown events in a legume rhizobia metapopulation.

Bacterial mutualists generate major fitness benefits for eukaryotes, reshaping the host phenotype and its interactions with the environment. Yet, microbial mutualist populations are predicted to generate mutants that defect from providing costly services to hosts while maintaining the capacity to exploit host resources. Here, we examined the mutualist service of symbiotic nitrogen fixation in a metapopulation of root-nodulating spp that associate with the native legume .

Interspecific conflict and the evolution of ineffective rhizobia.

Microbial symbionts exhibit broad genotypic variation in their fitness effects on hosts, leaving hosts vulnerable to costly partnerships. Interspecific conflict and partner-maladaptation are frameworks to explain this variation, with different implications for mutualism stability. We investigated the mutualist service of nitrogen fixation in a metapopulation of root-nodule forming Bradyrhizobium symbionts in Acmispon hosts.

Nonnodulating Bradyrhizobium spp. Modulate the Benefits of Legume-Rhizobium Mutualism.

Unlabelled: Rhizobia are best known for nodulating legume roots and fixing atmospheric nitrogen for the host in exchange for photosynthates. However, the majority of the diverse strains of rhizobia do not form nodules on legumes, often because they lack key loci that are needed to induce nodulation. Nonnodulating rhizobia are robust heterotrophs that can persist in bulk soil, thrive in the rhizosphere, or colonize roots as endophytes, but their role in the legume-rhizobium mutualism remains unclear.

Information-seeking behaviour of nurse teachers in a school of health studies: a soft systems analysis.

Aim: This paper reports a small-scale study, undertaken as part of a higher degree, which aims to explore the information-seeking behaviour of a group of lecturers, based on one site, delivering a nursing and midwifery curriculum in the School of Health Studies of a higher education institution.

Methodology: Checkland's [System thinking, System practice, Wiley, Chichester, 1981] soft systems methodology (SSM) was used as a theoretical model both to derive deeper insights into the survey data and suggest enhancements to this aspect of teacher activity. To obtain statistical data a survey design was employed, research methods including postal questionnaires complemented by selected interviews and a small amount of informal observation.