Differential Response of Bacterial Microdiversity to Simulated Global Change.

Global change experiments often observe shifts in bacterial community composition based on 16S rRNA gene sequences. However, this genetic region can mask a large amount of genetic and phenotypic variation among bacterial strains sharing even identical 16S regions. As such, it remains largely unknown whether variation at the sub-16S level, sometimes termed microdiversity, responds to environmental perturbations and whether such changes are relevant to ecosystem processes. Here, we investigated microdiversity within Curtobacterium, the dominant bacterium found in the leaf litter layer of soil, to simulated drought and nitrogen addition in a field experiment. We first developed and validated Curtobacterium-specific primers of the groEL gene to assess microdiversity within this lineage. We then tracked the response of this microdiversity to simulated global change in two adjacent plant communities, grassland and coastal sage scrub (CSS). Curtobacterium microdiversity responded to drought but not nitrogen addition, indicating variation within the genus of drought tolerance but not nitrogen response. Further, the response of microdiversity to drought depended on the ecosystem, suggesting that litter substrate selects for a distinct composition of microdiversity that is constrained in its response, perhaps related to tradeoffs in resource acquisition traits. Supporting this interpretation, a metagenomic analysis revealed that the composition of Curtobacterium-encoded carbohydrate-active enzymes (CAZymes) varied distinctly across the two ecosystems. Identifying the degree to which relevant traits are phylogenetically conserved may help to predict when the aggregated response of a 16S-defined taxon masks differential responses of finer-scale bacterial diversity to global change. IMPORTANCE Microbial communities play an integral role in global biogeochemical cycling, but our understanding of how global change will affect microbial community structure and functioning remains limited. Microbiome analyses typically aggregate large amounts of genetic diversity which may obscure finer variation in traits. This study found that fine-scale diversity (or microdiversity) within the bacterial genus Curtobacterium was affected by simulated global changes. However, the degree to which this was true depended on the type of global change, as the composition of Curtobacterium microdiversity was affected by drought, but not by nitrogen addition. Further, these changes were associated with variation in carbon degradation traits. Future work might improve predictions of microbial community responses to global change by considering microdiversity.

Managed care organizations' arrangements with nurse practitioners: a Connecticut perspective.

Executives in more than 50% of managed care organizations (MCOs) in New York and Connecticut were interviewed for information on the roles, participation, and listing of NPs as primary care providers. MCO executives are highly satisfied with their primary care provider NPs, particularly in women's health and geriatrics, secondary to spending more time teaching and explaining procedures than physicians. Among both health care professionals and the general public there is an overall lack of current knowledge and/or confusion about NPs and their practice. Eighty-two percent of executives in MCOs thought their organization should encourage the use of NPs as primary care providers. Beginning in the early 1960s, advanced practice nursing has shown steady growth. Research has found that NPs provide cost-effective, quality-driven patient care (Brown & Grimes, 1995; Cohen & Juszczak, 1997; Frampton & Wall, 1994; Hardy & Evans, 1995). Many thought health care reform would lead to an expansion of advanced practice nurses (APNs) and other nonphysician providers as primary care providers (Aiken & Salmon, 1994). Funding for and enrollment in graduate nursing programs rose nationwide (American Association of Colleges of Nursing, 1996). Anecdotal reports indicated that NPs were not included in MCO primary care provider panels. The purpose of this study was to explore MCO arrangements with nurse practitioners and the factors that influence them.

Managed care organizations' arrangements with nurse practitioners.

Thirty-four of 67 MCOs in New York and Connecticut responded to requests for information on the roles, participation, and listing of nurse practitioners as primary care providers or in other capacities. MCO executives report a high degree of satisfaction with NPs who serve as their primary care providers, especially in women's health and geriatrics, as they spend more time teaching and explaining procedures than physicians. Ongoing lack of up-to-date information and/or confusion about the scope of NP practice exists among both health care professionals and the public. Perceived differences in the scope of care provided by NPs was related to state regulations, physician practice patterns, and availability of primary care physicians. Eighty-five percent of MCO executives thought their organizations should encourage the use of NPs.