Fine-scale genetic population structure of southern pine beetle (Coleoptera: Curculionidae) in Mississippi forests

The southern pine beetle, Dendroctonus frontalis Zimmerman, is the most destructive insect pest of pine forests in the southeastern United States, Mexico, and Central America. Southern pine beetle aggressively attacks pine trees, and when in epidemic stages, they are capable of killing even the most healthy pine trees in a short period of time. Despite the amount of destruction caused by the southern pine beetle and the amount of monetary loss faced by the timber industry and recreation, the population genetics of this species has been limited to comparisons among distant geographic locations. This study investigates the fine-scale genetic population structure of the southern pine beetle in Mississippi. Very little genetic differentiation was observed among samples. Bayesian assignment testing failed to detect multiple groups within all samples; estimates of genetic differentiation and genetic distance were very low in magnitude; and a Mantel test did not reveal a significant relationship between genetic distance and geographic distance. These results suggest that management of the southern pine beetle needs to consider the potential movements of individuals within and among national forests and should be focused on a large scale, at least as big as continuously forested areas and possibly even multiple forests. These results further suggest that removal of beetle-infested trees is important.     

An Adaptable Staining Schedule for Plant Tissues

A general schedule for staining meristematic, maturing, and mature plant tissues is described. Treatment with a dilute aqueous solution of Delafield's hematoxylin is followed with staining in 0.1% safranin in 60% alcohol. Destaining of safranin may be partly accomplished in alcohol and completed by counterstaining with dilute fast green FCF in a xylene and alcohol mixture. Various modifications and adaptations are briefly discussed.     

Hospital training for general practice: views of trainees in the North Western region.

Vocational trainees in the North Western region who were in their general practice year completed a questionnaire concerning the hospital component of their training. Replies were received from 125 trainees, providing information about 451 hospital posts. In a total of 372 posts (85%) less than two hours of formal teaching a week was provided. Trainees stated that they received no informal teaching in nearly one third of posts. The orientation of teaching towards general practice was reported as greatest in the posts that were not part of a vocational training scheme. Study leave was applied for by doctors in only 163 (37%) posts, usually to prepare for or to sit an examination. There seem to be serious educational deficiencies in hospital posts that are used to train both general practitioners and other specialists. Improvements in both the quantity and quality of in service teaching are therefore needed urgently.     

Enucleation of mammalian cells by cytochalasin B. II. Formation of hybrid cells and heterokaryons by fusion of anucleate and nucleated cells

The development of methods for the formation of hybrid cells and heterokaryons by virus-induced fusion of chemically-enucleated cells and nucleated cells has been described. Heterokaryons and hybrid cells formed by fusion of anucleate mouse peritoneal macrophages (MPM) and nucleated mouse L and human HEp-2 cells were identified by mixed haemadsorption, by their sensitivity to trypsin and by their capacity to ingest antibody-coated sheep red blood cells. The expression of macrophage markers in these cells declined rapidly after fusion. Hybrid cell and heterokaryon formation was identified in mixed cultures of anucleate L cells and nucleated MPM, and was accompanied by the reactivation of DNA synthesis in the macrophage nuclei. Other hybrids and heterokaryons were formed by virus-induced fusion of anucleate MPM and nucleated chick embryo erythrocytes and anucleate L cells and nucleated HEp-2 cells. The value of anucleate-nucleate cell hybrids in the study of metabolic and genetic regulation in mammalian cells is discussed.