3-deoxy-2,5-DI-O-p-nitrobenzoyl-α-D-threo-pentofuranosyl bromide,a starting material for the synthesis of nucleosides

Hydrogenation (Raney nickel) of methyl 2,3-anhydro-α- and β-D-lyxo-furanoside (3 and 12) for 12 h at $\text{60}\text{60}$ lb.in.-2 afforded methyl 3-deoxy-α- and β-D-threo pentofuranoside (4 and 13). These were p-nitrobenzoylated to give the 2,5-di-p-nitrobenzoates (5b and 14b) which, on treatment with hydrogen bromide in acetyl bromide—acetic acid—dichloromethane, afforded the title compound (6b). The structure of compound 4 was established by conversion into the previously prepared 2,5-dibenzoate 5a of known structure, and the anomeric configuration of 6b was established by comparison of its optical rotation and the signals of its anomeric proton with those of methyl 3-deoxy-D-threo-pentofuranosides.     

Physiological implications of SWEETs in plants and their potential applications in improving source–sink relationships for enhanced yield

The sugars will eventually be exported transporters (SWEET) family of transporters in plants is identified as a novel class of sugar carriers capable of transporting sugars, sugar alcohols and hormones. Functioning in intercellular sugar transport, SWEETs influence a wide range of physiologically important processes. SWEETs regulate the development of sink organs by providing nutritional support from source leaves, responses to abiotic stresses by maintaining intracellular sugar concentrations, and host–pathogen interactions through the modulation of apoplastic sugar levels. Many bacterial and fungal pathogens activate the expression of SWEET genes in species such as rice and Arabidopsis to gain access to the nutrients that support virulence. The genetic manipulation of SWEETs has led to the generation of bacterial blight (BB)-resistant rice varieties. Similarly, while the overexpression of the SWEETs involved in sucrose export from leaves and pathogenesis led to growth retardation and yield penalties, plants overexpressing SWEETs show improved disease resistance. Such findings demonstrate the complex functions of SWEETs in growth and stress tolerance. Here, we review the importance of SWEETs in plant–pathogen and source–sink interactions and abiotic stress resistance. We highlight the possible applications of SWEETs in crop improvement programmes aimed at improving sink and source strengths important for enhancing the sustainability of yield. We discuss how the adverse effects of the overexpression of SWEETs on plant growth may be overcome.     

Effect of water stress on protein content in two maize cultivars differing in drought resistance

The changing pattern, of WSD and concomitant protein changes were scanned in twoZea mays cultivars, with differential sensitivity to water stress. Increasing protein values were recorded in resistant cv. Ageti-76 with decreasing osmotic potentials of substrate (on 3rd day of stress), although the values in susceptible cv. Vijay remained almost on a par with the controls. In another experiment both the cultivars revealed initial increase of protein on 2nd day at osmotic potentials of - 2 and -4 × 10⁶ Pa, however, values declined up to day 7 of stress. WSD showed an increasing trend in both the experiments, although slightly higher values of WSD were registered in cv. Ageti-76 in comparison with cv. Vijay. The significance of protein changes in reference to drought is discussed.     

Post-monsoon seasonal variation of prokaryotic diversity in solfataric soil from the North Sikkim hot spring

International Microbiology - The solfataric soil sediments of the hot springs of Sikkim located at Yume Samdung and Lachen valley were studied for deciphering the bacterial diversity. The main aim...     

Biochemical changes in progressive muscular dystrophy. XI. Cyclic nucleotides in the skeletal and cardiac muscle of normal and dystrophic mice

cAMP and cGMP contents were determined in the skeletal and cardiac muscle of normal and dystrophic mice. cAMP content increased in the dystrophic muscle at every stage of the disease whereas cGMP content decreased in the preliminary stages and increased at the terminal stage of the disease. The content of both nucleotides per heart was not affected in murine dystrophy. Thus, levels of cyclic nucleotides appear to be selectively altered in dystrophic skeletal muscle.