Jute—World’s foremost bast fibre. I. Botany,agronomy, diseases and pests

India and Pakistan together contain over 96% of the world’s acreage devoted to this crop and produce nearly 97% of the world’s total supply. Two species of Corchorus are involved. The production of fibre has increased from about one million tons at the beginning of the present century to about two million tons today.     

Structural considerations for designing adenosine analogs as selective inhibitors of Trichomonas sp. glyceraldehyde-3- phosphate dehydrogenase

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of pathogenic protozoa Trichomonas vaginalis (TvGAPDH) is an attractive drug target since this parasite lacks functional citric acid cycle and is dependent solely on glycolysis for its energy requirements. The three dimensional structure of TvGAPDH dimer has been generated by homology modelling based on the crystal structure of human liver GAPDH. Comparison of the NAD;{+} binding pocket of the modeled TvGAPDH with human GAPDH (hGAPDH) reveals the presence of a hydrophobic pocket near the N-6 position of adenine ring as well as a hydrophobic cleft near O-2' of the adenosine ribose that are absent in the human enzyme. In order to exploit these structural differences adenosine and several adenosine analogs with substitution on N-6 position of adenine ring or 2' position of ribose sugar or both have been studied by docking experiments using the program AutoDock version 3.0.5. Our docking result suggests that bulkier hydrophobic substitution at the N-6 position of the adenine ring could form more stable complexes with TvGAPDH than with hGAPDH. An improvement of binding occurs in TvGAPDH when methoxybenzamido group has been introduced at the O-2' position of the ribose sugar. The combination of N-6 and O-2' substitutions may have produced significantly improved inhibitors. Our study may help in identifying structural elements involved in the origin of selectivity at the NAD;{+} binding pocket of TvGAPDH. This study could further be extended for future anti-trichomonal drug design strategies in order to control trichomoniasis.     

Biological activity and conformational isomerism in position 9 analogues of the des-1-tryptophan,3-beta-cyclohexylalanine-alpha-factor from Saccharomyces cerevisiae

Analogues of the des-1-tryptophan,3-beta-cyclohexylalanine-alpha-factor of Saccharomyces cerevisiae, where the glycyl residue of position 9 was replaced by D-Ala, L-Ala, D-Leu, and L-Leu, were synthesized and evaluated by morphogenesis assays and circular dichroism spectroscopy. Synthesis was accomplished in solution phase with mixed anhydrides and p-nitrophenyl active esters as the coupling agents. All crude dodecapeptides were purified to greater than 98% homogeneity by preparative high-performance liquid chromatography on a reversed-phase column. The Gly9, D-Ala9, and D-Leu9 analogues elicited morphogenic alterations in MATa strains of S. cerevisiae at concentrations of 1-2 micrograms/mL and exhibited similar CD patterns in both trifluoroethanol and tris(hydroxymethyl)aminomethane buffer, pH 7.4. In contrast, the L-Ala9 and L-Leu9 analogues were more than 200 times less active in the morphogenesis assay and had markedly different CD spectra. These results demonstrate that the position 9 residue plays an important role in determining the biological activity and solution conformation of alpha-factor. We suggest the presence of a type II beta-turn in the Lys7-Gln10 region when the alpha-factor assumes its biologically active conformation.     

Abnormalities of the erythrocyte membrane in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a hematologic malignancy characterized by excessive growth of myeloid cells and their progenitors. The proportion of spectrin dimers compared to tetramers extracted from membranes at 4 degrees C, under low ionic strength conditions, increased in CML erythrocytes. These also displayed abnormal thermal sensitivity (between 45 and 46 instead of 49 degrees C). Crosslinking with the bifunctional reagent, dimethyl adipimidate (8.6 A) showed significant organizational modification of not only spectrin, but other cytoskeletal components such as ankyrin, bands 4.2 and 5. Enhanced concanavalin A (Con-A) agglutinability of CML erythrocytes also suggests altered topographic distribution of a functionally important membrane protein, band 3. The anion transport activities of erythrocytes from patients with CML and normal donors were comparable. In CML erythrocytes, significant reduction in the number of ankyrin-binding sites, present in the cytoplasmic domain of band 3, may lead to partial loss of cytoskeletal anchorage to the bilayer and account for their increased Con-A agglutinability and heat sensitivity and may lead to their premature removal from the circulation.     

The excised heat-shock domain of alphaB crystallin is a folded, proteolytically susceptible trimer with significant surface hydrophobicity and a tendency to self-aggregate upon heating

The lens protein, alpha-crystallin, is a molecular chaperone that prevents the thermal aggregation of other proteins. The C-terminal domain of this protein (homologous to domains present in small heat-shock proteins) is implicated in chaperone function, although the domain itself has been reported to show no chaperone activity. Here, we show that the domain can be excised out of the intact alphaB polypeptide and recovered directly in pure form through the transfer of CNBr digests of whole lens homogenates into urea-containing buffer, followed by dialysis-based refolding of digests under acidic conditions and a single gel-filtration purification step. The folded (beta sheet) domain thus obtained is found to be (a) predominantly trimeric, and to display (b) significant surface hydrophobicity, (c) a marked tendency to undergo degradation, and (d) a tendency to aggregate upon heating, and on exposure to UV light. Thus, the twin 'chaperone' features of multimericity and surface hydrophobicity are clearly seen to be insufficient for this domain to function as a chaperone. Since alpha-crystallin interacts with its substrates through hydrophobic interactions, the hydrophobicity of the excised domain indicates that separation of domains may regulate function; at the same time, the fact is also highlighted that surface hydrophobicity is a liability in a chaperone since heating strengthens hydrophobic interactions and can potentially promote self-aggregation. Thus, it would appear that the role of the N-terminal domain in alpha-crystallin is to facilitate the creation of a porous, hollow structural framework of >/=24 subunits in which solubility is effected through increase in the ratio of exposed surface area to buried volume. Trimers of interacting C-terminal domains anchored to this superstructure, and positioned within its interior, might allow hydrophobic surfaces to remain accessible to substrates without compromising solubility.     

Molecular phylogeny of silk producing insects based on internal transcribed spacer DNA1

Silk moths are the best studied silk secreting insects and belong to the families Bombycidae and Saturniidae. The phylogenetic relationship between eleven silk producing insects was analyzed using the complete DNA sequence of the internal transcribed spacer DNA 1 locus. The PCR amplification and sequence analysis showed variation in length ranging from 138 bp (Antheraea polyphemus) to 911 bp (Hyalopora cecropia). Microsatellite sequences were found and was be used to distinguish Saturniidae and Bombycidae members. The nucleotide sequences were aligned manually and used for construction of phylogenetic trees based on Maximum parsimony and Maximum likelihood methods. The topology in both the approaches yielded a similar tree that supports the ancestral position of the Antheraea assama.     

Induced Homoeologous Pairing for Transfer of Useful Variability for High Grain Fe and Zn from <Emphasis Type="Italic">Aegilops kotschyi</Emphasis> into Wheat

Biofortification of bread wheat by the transfer of useful variability of high grain Fe and Zn from Aegilops kotschyi through induced homoeologous pairing is the most feasible approach to alleviate micronutrient malnutrition worldwide. Deficiency of chromosome 5B in interspecific hybrids allows homoeologous pairing and recombination of chromosomes of wheat with those of the related species. The interspecific hybrid plants without 5B chromosome showed much higher chromosome pairing than did the plants with 5B. The F₁ plants without 5B chromosome were selected and repeatedly backcrossed with wheat cultivar PBW343. The chromosome number of BC₂F₁ plants ranged from 43 to 60 with several univalents and multivalents. Molecular markers and GISH analysis confirmed the introgression of U/S chromosomes of Ae. kotschyi and their fragments in wheat. The BC₂F₂ plants showed up to 125 % increase in Fe and 158 % increase in Zn compared to PBW343 with Lr24 and Yr36. Induced homoeologous pairing in the absence of 5B was found to be an effective approach for transfer of useful variability for enhanced grain Fe and Zn content for biofortification of wheat for high grain micronutrient content.