Intersubgeneric hybridization of soybeans with a wild perennial species,Glycine clandestina Wendl

Summary The exploitation of wild perennial species of subgenus Glycine has been formidable in soybean breeding programs because of extremely poor crossability and an early pod abortion. The combination of gibberellic acid application to hybridized gynoecia and improved seed culture media formulations resulted in a new intersubgeneric hybrid between Glycine max (L.) Merr. (2n=40) and G. clandestina Wendt. (2n=40). Of the 31 immature seeds cultured, 1 regenerated 21 plants through organogenesis while the remaining 30 failed to germinate. All the regenerated plants were similar morphologically, carried expected 2n=40, possessed hybrid isozyme patterns and were completely sterile. Complete absence of chromosome pairing was observed in 40.9% sporocytes. The occurrence of 1 to 6 loosely paired rod bivalents suggests some possibilities of allosyndetic pairing. Hybrid plants set aborted pods after backcrossing to G. max.     

Reactivity of glycoconjugate in membrane system II: Can a neutral glycolipid function as lectin receptor in the presence of gangliosides in plasma membrane?

To examine how surface Potential controls the reactivity of glycoconjugates at cell surface, the interaction of galactose-sPecific lectinse.g. peanut agglutinin,Ricinus cummunis agglutinin with liPosomes bearing asialo GM₁ were studied in the Presence of varying amount of ganglioside mixture, GM_n. The Presence of 5% GM_n causes comPlete slowing down of PreciPitin reaction and thereby make carbohydrate moiety of asialo GM₁ comPletely inaccessiblei.e. ‘cryPtic’. In contrast the Presence of 1–2% GM_n enhances the aPParent rate and amPlitude of the PreciPitin reaction as surface Potential becomes more negative. The relevance of the findings has been discussed in relation to the exPression and involvement of the cell-surface sialic acid residues during develoPment and differentiation.     

The geometries of interacting arginine-carboxyls in proteins

The geometries are reported for interacting arginine-carboxyl pairs obtained from 37 high resolution protein structures solved to a resolution of 2.0 A or better. The closest interatomic distance between the guanidinium and carboxyl is less than 4.2 A for 74 arginine and carboxyl groups, with the majority of these lying within hydrogen-bonding distance (2.6-3.0 A). Interacting pairs have been transformed into a common orientation, and arginine-carboxyl, and carboxyl-arginine geometries have been calculated. This has been defined in terms of the spherical polar angles T theta, T phi, and the angle P, between the guanidinium and carboxyl planes. Results show a clear preference for the guanidinium and carboxyl groups to be approximately coplanar, and for the carboxyl oxygens to hydrogen bond with the guanidinium nitrogens. Single nitrogen-single oxygen is the most common type of interaction, however twin nitrogen-twin oxygen interactions also occur frequently. The majority of these occur between the carboxyl oxygens and the NH1 and NE atoms of the arginine, and are only rarely observed for NH1 and NH2. The information presented may be of use in the modelling of arginine-carboxyl interactions within proteins.     

Histology of the normal and retained equine testis

Abdominal, inguinal and scrotal testes of horses were examined grossly and by light microscopy. An average of 1.5, 2.3 and 4.6 layers of spermatogenic cells, and mean seminiferous tubule diameters of approximately 66.2, 83.6 and 146.6 micron in the abdominal, inguinal and scrotal testes, respectively, were recorded. The interstitial spaces and the number of interstitial cells (of Leydig) seemed to be increased while spermatogenesis appeared to be arrested in the retained testes. Early spermatocytes were the most mature stages of the spermatogenic cells in the retained testes. An extensive vacuolation of spermatogenic cells was evident in these testes. The changes may result due to a high temperature of the abdominal environment in concert with the altered production of androgens.     

Inheritance and expression of tissue-specific catalase activity during development and aging in mice

The catalase activity in the liver, kidney, lung, and blood hemolysate was measured in newborn, 21-, 70-, 175-, and greater than 400-day-old mice from the strains BALB/c, Csb, C3H/HeSnJ, C3H/S, C57BL/6J, SW, and 129/ReJ. Catalase activity was found to be highest in the liver (approximately 0.33 U/mg protein) followed by the kidney (approximately 0.13 U/mg protein), lung (approximately 0.05 U/mg protein), and blood hemolysate (approximately 0.03 U/mg protein). ANOVA analysis indicated significant differences in enzyme activity among strains and age groups studied. The developmental profiles of enzyme activity were tissue and strain specific. Catalase activity in the blood, for example, was generally higher at birth and at old age, whereas the kidney catalase activity was low at birth and increased substantially with age. Strains could be classified as normal (129/ReJ, BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (C57BL/6J, SW), and acatalasemic (Csb) with respect to enzyme activity and it was on this basis that the inheritance of the catalase phenotype was studied using appropriate crosses. The enzyme activity level in each tissue appears to be governed by a unique set of genetic regulators/modifiers that interact with a single structural gene (Cs) or its product to produce the catalase phenotype. Some of these (e.g., Ce-1 and Ce-2) have been previously described but based on the results of various crosses reported here, more must exist that remain still uncharacterized at the molecular level. Models proposed for the inheritance of the catalase phenotype vary in complexity from single allelic differences between strains (e.g., BALB/c x Csb; blood) to a system of multiple interacting genetic determinants (e.g., BALB/c x Csb; liver) each having dominant (e.g., C57BL/6J over BALB/c; liver) and recessive components (e.g., gene(s) conferring the acatalasemic phenotype in BALB/c x Csb; blood and kidney). Such results are important and offer an interesting model to further characterize aspects of eukaryotic gene regulation.     

Forest vegetation of the Himalaya

This review deals with the forest vegetation of the Himalaya with emphasis on: paleoecological, phytogeographical, and phytosociological aspects of vegetation; structural and functional features of forest ecosystem; and relationship between man and forests. The Himalayan mountains are the youngest, and among the most unstable. The rainfall pattern is determined by the summer monsoon which deposits a considerable amount of rain (often above 2500 mm annually) on the outer ranges. The amount of annual rainfall decreases from east to west, but the contribution of the winter season to the total precipitation increases. Mountains of these dimensions separate the monsoon climate of south Asia from the cold and dry climate of central Asia. In general, a rise of 270 m in elevation corresponds to a fall of 1°C in the mean annual temperature up to 1500 m, above which the fall is relatively rapid. Large scale surface removals and cyclic climatic changes influenced the course of vegetational changes through geological time. The Himalayan ranges, which started developing in the beginning of the Cenozoic, earlier supported tropical wet evergreen forests throughout the entire area (presently confined to the eastern part). The Miocene orogeny caused drastic changes in the vegetation, so much so that the existing flora was almost entirely replaced by the modern flora. Almost all the dominant forest species of the Pleistocene continue to maintain their dominant status to the present. Presently the Himalayan ranges encompass Austro-Polynesian, Malayo-Burman, Sino-Tibetan, Euro-Mediterranean, and African elements. While the Euro-Mediterranean affinities are well represented in the western Himalayan region (west of 77°E long.), the Chinese and Malesian affinities are evident in the eastern region (east of 84°E long.). However, the proportion of endemic taxa is substantial in the entire region. A representation of formation types in relation to climatic factors, viz., rainfall and temperature, indicates that boundaries between the types are not sharp. Formation types often integrate continuously, showing broad overlaps. Climate does not entirely determine the formation type, and the influence of soil, fire, etc., is also substantial. The ombrophilous broad leaf forests located in the submontane belt (< 1000 m) of the eastern region are comparable to the typical tropical rain forests. On the other extreme, communities above 3000 m elevation are similar to sub-alpine and alpine types. From favorable to less favorable environments, as observed with decreasing moisture from east to west, or with decreasing temperature from low to high elevations, the forests become increasingly open, shortstatured and simpler, with little vertical stratification. Ordination of forest stands distributed within 300–2500 m elevations of the central Himalaya, by and large indicates a continuity of communities, with scattered centers of species importance values in the ordination field. Within the above elevational transect, sal (Shorea robusta) and oak (Quercus spp.) forests may be designated as the climax communities, respectively, of warmer and cooler climates. The flora of a part of the central Himalayan region is categorized as therohemigeophytic and that of a part of the western Himalayan region as geochamaephytic. An analysis of population structure over large areas in the central Himalaya, based on density-diameter distribution of trees, suggests that oldgrowth forests are being replaced by even-aged successional forests, dominated by a few species, such asPinus roxburghii. Paucity of seedlings of climax species, namelyShorea robusta andQuercus spp. over large areas is evident. The Himalayan catchments are subsurface-flow systems and, therefore, are particularly susceptible to landslips and landslides. Loss of water and soil in terms of overflow is insignificant. Studies on recovery processes of forest ecosystems damaged due to shifting cultivation or landslides indicate that the ecosystems can recover quite rapidly, at least in elevations below 2500 m. For example, on a damaged forest site, seedlings of climax species (Quercus leucotrichophora) appeared only 21 years after the landslide. In the central Himalaya, the biomass of a majority of forests (163-787 t ha^?1) falls within the range (200-600 t ha^?1) given for many mature forests of the world, and the net primary productivity (found in the range of 11.0–27.4 t ha^?1 yr^?1) is comparable with the range of 20–30 t ha^?1 yr^?1 given for highly productive communities of favorable environments. In most of the forests of this region, the litter fall values (2.1-3.8 t C ha^?1 yr^?1) are higher than the mean reported for warm temperate forests (2.7 t C ha^?1 yr^?1). Of the total litter, the tree leaves account for 54–82% in the Himalayan forests. The rate of decomposition of leaves in some broadleaf species of submontane belt (0.253-0.274% day^?1) are comparable with those reported for some tropical rain forest species. Because of the paucity of microorganisms and microarthropods in the forest litter and soil, high initial C:N ratio and high initial lignin content in leaves, the rate of leaf litter decomposition inPinus roxburghii is markedly slower than in other species of the central Himalaya. The fungal species composition of the leaf litterof Pinus roxburghii is also distinct from those of other species. A greater proportion of nutrients is accumulated in the biomass component of the Himalayan forests than in the temperate forests. Although litter fall is the major route through which nutrients return from biomass to the soil pool, a substantial proportion of the total return is in the form of throughfall and stemflow. Among the dominant species of the central Himalaya, retranslocation of nutrients from the senescing leaves was markedly greater inPinus roxburghii than inQuercus spp. andShorea robusta. Consequently, the C:N ratio of leaf litter is markedly higher inPinus roxburghii than in the other species. Immobilization of nutrients by the decomposers of the litter with high C:N ratio is one of the principal strategies through whichPinus roxburghii invades other forests and holds the site against possible reinvasion by oaks. Observations on the seasonality of various ecosystem functions suggest that Himalayan ecosystems are geared to take maximum advantages of the monsoon period (rainy season). Most of the human population depends on shifting-agriculture in the eastern region and on settled agriculture in the central and western regions. Either of these is essentially a forest-dependent cultivation. Each unit of agronomic energy produced in the settled agriculture entails about seven units of energy from forests. Consequently, forests with reasonable crown cover account for insignificant percentage of the land. Tea plantations and felling of trees for timber, paper pulp, etc., are some of the major commercial activities which adversely affected the Himalayan forests.     

Binding and aggregation of the 25-kilodalton toxin of Bacillus thuringiensis subsp. israelensis to cell membranes and alteration by monoclonal antibodies and amino acid modifiers

The 25-kilodalton toxin of Bacillus thuringiensis subsp. israelensis binds irreversibly to Aedes albopictus cells, Choristoneura fumiferana cells, and erythrocytes. The binding to cells increased with both toxin concentration and time and when the cells were first preincubated with unlabeled toxin. Binding data indicated a two- to threefold increase in the rate of binding after the amount of the membrane-bound toxin reached approximately 3.5 fmol/3 x 10(5) A. albopictus cells or 3.3. fmol/2 x 10(5) C. fumiferana cells. When this level of bound toxin was reached, the toxins also began forming aggregates at the cell membrane. The toxin aggregates were extracted with 10% Triton X-100 and separated from the monomers with a 5 to 20% sucrose density gradient. The toxin aggregates isolated from A. albopictus and C. fumiferana cell membranes were ca. 400 kilodaltons, while those isolated from human erythrocytes were significantly smaller. The proportion of the toxin found in aggregate form increased rapidly with the amount of toxin bound; however, the molecular size of the aggregates remained constant. Eleven monoclonal antibodies raised against the native form of the toxin blocked 80 to 97% of the toxin binding to cells. The epitope of one of these monoclonal antibodies was mapped to a domain which included the cysteine, suggesting the importance of the domain around this amino acid to binding. Toxin binding and cell lysis were also inhibited by treating the toxin with HgCl2, further indicating the importance of the C-terminal hydrophobic cysteine-containing domain in cytolytic activity of the 25-kilodalton protein.     

Male reproductive success in harem troops of hanuman langurs (Presbytis entellus)

Based on cross-sectional and longitudinal data collected in 1967–1988 by various observers, male reproductive success was studied in the Hanuman langurs of Jodhpur, India. The harem-structured social organization ensures a high degree of paternity certainty. Births occur throughout the year, with significant peaks and minima in March and November, respectively (n =398).The interbirth interval averages 16.7 months (n = 114).The duration of harem residencies varies between 3 days and ≥ 74.0 months, with a mean of 26.5 (n = 64). Harem holder replacements occur during all months of the year. No male achieves residency in more than one troop, suggesting that residency is associated with a distinct peak in the resource holding potential of a given male. Reproductive success among males varies considerably. Male mortality is high due to migration and intrasexual competition, leading to an adult sex ratio of 1:4.9. It is estimated that one-quarter of all adult males will never gain harem residency. Conceptions achieved outside harem residencies are so rare (4.7%) that a viable low-risk strategy, opting for longevity instead of harem residency, is unlikely. Tenure length has a stronger influence on male reproductive success than harem size because interbirth intervals are significantly shorter in small harems than in larger ones. It is assumed that females in one-male breeding structures compete for sperm and that such competition is more intense in larger harems.     

Characterization of cytosolic phosphoglucoisomerase from immature wheat (Triticum aestivum L.) endosperm

Phosphoglucoisomerase from cytosol of immature wheat endosperm was purified 650-fold by ammonium sulphate fractionation, isopropyl alcohol precipitation, DEAE-cellulose chromatography and gel filtration through Sepharose CL-6B. The enzyme, with a molecular weight of about 130,000, exhibited maximum activity at pH 8.1. It showed typical hyperbolic kinetics with both fructose 6-P and glucose 6-P withK _m of 0.18 mM and 0.44mM respectively. On either side of the optimum pH, the enzyme had lower affinity for the substrates. Using glucose 6-P as the substrate, the equilibrium was reached at 27% fructose 6-P and 73% glucose 6-P with an equilibrium constant of 2.7. The ΔF calculated from the apparent equilibrium constant was +597 cal mol^-1. The activation energy calculated from the Arrhenius plot was 5500 cal mol^-1. The enzyme was completely inhibited by ribose 5-P, ribulose 5-P and 6-phosphogluconate, withK _i values of 0.17, 0.25 and 0.14 mM respectively. The probable role of the enzyme in starch biosynthesis is discussed.     

Cholesterol binding reserve of hyperlipemic rat serum lipoproteins in chronic ethanol administration

Chronic administration of ethanol in rats caused the reduction of serum cholesterol binding reserve. The very low density and high density lipoproteins, main serum cholesterol binding reserves, were slightly increased with corresponding increases in their lipid and protein components during initial stage of alcohol consumption. However, these capacities get deminished during reversal of hyperlipemia induced by prolonged action of ethanol. This situation may be an early indicator for the initiation of hepatic damage and a variety of secondary effects of ethanol.