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.     

Activities of the enzymes of formaldehyde catabolism in recombinant strains of <Emphasis Type="Italic">Hansenula polymorpha</Emphasis>

Activities of the enzymes of formaldehyde (FA) catabolism in recombinant strains of the methylotrophic yeast Hansenula polymorpha overproducing NAD⁺- and glutathione-dependent formaldehyde dehydrogenase (FADH) were studied under different cultivation conditions and at elevated FA content. Southern dot-blot analysis confirmed the presence of six to eight copies of the target FLD1 gene in stable recombinant clones of H. polymorpha. Under certain cultivation conditions, the transformants resistant to elevated FA concentrations were shown to produce FADH and other bioanalytically important enzymes: formate dehydrogenase, alcohol dehydrogenase, alcohol oxidase, and formaldehyde reductase. The optimal cultivation conditions for recombinants were determined, resulting in maximum synthesis of FADH: methanol as a carbon source, methylamine as a nitrogen source, FA as an inducer, temperature of 37°C, and cells in the early exponential phase of growth.     

The gene pool of Belgorod oblast population: study of biochemical gene markers in populations of Ukraine and Belarus and the position of the Belgorod population in the Eastern Slavic gene pool system

The characteristics of the gene pools of indigenous populations of Ukraine and Belarus have been studied using 28 alleles of 10 loci of biochemical gene markers (HP, GC, TF, PI, C'3, ACP1, GLO1, PGM1, ESD, and 6-PGD). The gene pools of the Russian and Ukrainian indigenous populations of Belgorod oblast (Russia) and the indigenous populations of Ukraine and Belarus have been compared. Cluster analysis, multidimensional scaling, and factor analysis of the obtained data have been used to determine the position of the Belgorod population gene pool in the Eastern Slavic gene pool system.     

Lipid Auxotrophy and the Effect on Lipid Composition of Entamoeba invadens*†

SYNOPSIS. A medium for the axenic cultivation of Entamoeba invadens has been developed. Serum, an essential constituent of conventional media, has been replaced by a mixture of albumin, unsaturated fatty acids, Tween, and cholesterol to control the lipid composition of the medium. Entamoeba invadens requires both cholesterol and unsaturated fatty acids for growth. The fatty acid composition of the phospholipids of the ameba reflects that of the medium to a great extent, especially with regard to the unsaturated fatty acids. The amount of membrane bounded cholesterol depends on the cholesterol concentration in the medium.     

Production of flavin mononucleotide by metabolically engineered yeast Candida famata

Recombinant strains of the flavinogenic yeast Candida famata able to overproduce flavin mononucleotide (FMN) that contain FMN1 gene encoding riboflavin (RF) kinase driven by the strong constitutive promoter TEF1 (translation elongation factor 1α) were constructed. Transformation of these strains with the additional plasmid containing the FMN1 gene under the TEF1 promoter resulted in the 200-fold increase in the riboflavin kinase activity and 100-fold increase in FMN production as compared to the wild-type strain (last feature was found only in iron-deficient medium).Overexpression of the FMN1 gene in the mutant that has deregulated riboflavin biosynthesis pathway and high level of riboflavin production in iron-sufficient medium led to the 30-fold increase in the riboflavin kinase activity and 400-fold increase in FMN production of the resulted transformants. The obtained C. famata recombinant strains can be used for the further construction of improved FMN overproducers.     

Construction of the flavinogenic yeast Candida famata strains with high riboflavin kinase activity using gene engineering

The recombinant strains of the flavinogenic yeast Candida famata, which contain the DNA fragment consisting of the FMN1 gene (encoding the riboflavin kinase, enzyme that converts riboflavin to flavinmononucleotide) driven by the strong promoters (the regulated RIB1 or constitutive TEF1 promoter) were isolated. Riboflavin kinase activity in the isolated transformants was tested. The 6-8-fold increase of the riboflavin kinase activity was shown in the recombinant strains containing the integrated Debaryomyces hansenii FMN1 gene under the strong constitutive TEF1 promoter. The recombinant strains can be used for the following construction of flavinmononucleotide overproducers.     

Genetic demographic analysis of western Ukrainian populations: the marriage structure of populations from the Khmel'nitskii oblast with respect to ethnicity and birthplace

Ukrainians account for 85 and 91% of the populations of the city of Khmel'nitskii and the town of Starokonstantinov (Khmel'nitskii oblast, western Ukraine), respectively, and for 97% of the rural population of the Khmel'nitskii oblast. The proportions of Russians in the urban and rural populations of the Khmel'nitskii oblast are 7-10 and 1%, respectively. Between 1960 and 1995-1998, the proportions of Ukrainians in all populations studied increased and the proportion of interethnic marriages steadily decreased. The marriage association coefficient (K) with respect to ethnicity varied from 0.35 to 0.76 in different years. The highest assortative marriage indices (A') with respect to ethnicity were 75-98 and 71-84% in Ukrainians and Jews, respectively. The migration coefficient was 0.58-0.77. Western Ukrainian populations differ from eastern Ukrainian ones in a steadily decreasing outbreeding component.