EFFECTS OF HUMAN ACTIVITIES ON STRUCTURE AND COMPOSITION OF WOODY SPECIES OF THE NOKREK BIOSPHERE RESERVE OF MEGHALAYA,NORTHEAST INDIA

Aims Our study was conducted in the Nokrek Biosphere Reserve (NBR) in the Garo hills districts of Meghalaya, Northeast India. Our aim was to assess the effects of human activities on plant diversity,population structure and regeneration.Methods We selected a representative 1.2 hm2 stand in both the core and buffer zones of NBR. Structure and composition were determined by randomly sampling square quadrats, population structure was assessed by determining age structure, and regeneration was assessed by measuring densities of seedling, sapling and adult trees.Important findings More woody species were recorded from the core zone than the buffer zone (87 vs. 81 species), and there were a large number of tropical, temperate, and Sino-Himalayan, Burma-Malaysian and Malayan elements, primitive families and primitive genera. The trees were distributed in three distinct strata,canopy, subcanopy and sapling. Subcanopy and sapling layers had the highest species richness (81％ -88％ ). Lauraceae and Euphorbiaceae were the dominant families in terms of the number of species, and a large number of families were represented by single species. Most woody species (57 ％ - 79 ％ ) were contagiously distributed and had low frequency ( ＜ 20％ ). Although stand density was high in the buffer zone, its basal area was low compared to the stand in the core zone. Low similarity and high β-diversity indicate marked differences in species composition of the stands. Shannon diversity index was high in both the stands, while Simpson dominance index was low. The diameter-class distribution for dominant species revealed that the most had a large number of young individuals in their populations. Preponderance of tree seedlings, followed by a steep decline in population density of saplings and adult trees, indicated that the seedling to sapling stage was the most critical in the life cycle of the tree populations. Most species (42 ％ - 48 ％ ) had no regeneration,25 ％ - 35 ％ had good/fair regeneration, and the rest had poor regeneration or reoccurred as immigrants.     

Uterine estrogen receptor in vivo: phosphorylation of nuclear specific forms on serine residues

We have characterized further the heterogeneous nuclear-specific doublet forms of the mouse uterine estrogen receptor (ER). Estrogen treatment produced the multiple nuclear ER forms of 65 and 66.5 kDa, which were isolated and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Soluble ER preparations exhibited only a single 65-kDa form. Isolation of the individual nuclear ER forms and reanalysis demonstrated that formation of the multiple bands was not due to artifacts of nuclear sample preparation or the presence of contaminating proteins. Analysis of individual uterine cell types (epithelial and stromal/myometrium) indicated that both ER forms were present in both cell fractions. Fractionation of nuclear components with low salt showed that both ER forms were found in the salt-resistant fraction. Extraction of nuclei with high salt (0.6 M KCl) solubilized both ER forms. Phosphorylation was studied as a protein modification to account for the multiple forms. Incorporation of 32P into uterine protein both in vivo and in intact tissue incubation indicated 32P labeling of uterine nuclear ER after hormone treatment. Both nuclear ER forms are labeled, although the 66.5-kDa form appears to be more heavily labeled. Phosphoamino acid analysis of the immunopurified 32P-labeled ER from intact uterine tissue indicated phosphoserine as the only phospholabeled residue. These data suggest that phosphorylation is associated with the physiological functioning of the ER in response to hormone and produces the heterogeneous ER forms in the nucleus.