Growth and yield of groundnut (Arachis hypogaea L.) as influenced by weed management practices and Rhizobium inoculation

Groundnut (Arachis hypogaea L.) productivity in India is low, because of many problems beset in its cultivation. One of the serious problems are weeds. Groundnut yield losses due to weeds have been estimated as high as 24 to 70 percent. This has created a scope for using herbicides in groundnut crop. A field investigation was carried out during kharif (rainy) season of 2001-2002 on a sandy loam soil at College Agronomy Farm, B.A. College of Agriculture, Gujarat Agricultural University, Anand, India to study the effect of weed management practices and Rhizobium inoculation on growth and yield of groundnut (Arachis hypogaea L.). Ten weed control treatments, comprising four treatments of sole application of fluchloralin, pendimethalin, butachlor and metolachlor, respectively each applied at 1.0 kg ha(-1); four treatments comprising of an application of the same herbicides at the same levels coupled with one hand weeding at 30 DAS; one weed-free treatment (hand weedings at 15, 30, 45 DAS); and one unweeded control. All 10 treatmets were combined with and without Rhizobium inoculation (i.e. a total of 20 treatment combinations) under a factorial randomized complete block design (FRBD) with four replications. Minimum weed dry matter accumulation (70 kg/ha) with higher weed control efficiency (90.70%) was recorded under an integrated method i.e. pendimethalin at 1.0 kg ha(-1) + hand weeding at 30 DAS, which also resulted in maximum pod yield (1773.50 kg ha(-1)). This treatment was comparable to fluchloralin applied at 1.0 kg ha(-1) combined with hand- weeding at 30 DAS. Weedy conditions in the unweeded control treatment reduced pod yield by 29.90-35.95% as compared to integrated method. Significantly higher pod yield was obtained with Rhizobium inoculation than the mean value of all treatments without inoculation. For most agronomical parameters examined, Rhizobium inoculation and weed control treatments were independent in their effect.     

Hydrogen sulfide mediates vasoactivity in an O2-dependent manner

Hydrogen sulfide (H(2)S) has recently been shown to have a signaling role in vascular cells. Similar to nitric oxide (NO), H(2)S is enzymatically produced by amino acid metabolism and can cause posttranslational modification of proteins, particularly at thiol residues. Molecular targets for H(2)S include ATP-sensitive K(+) channels, and H(2)S may interact with NO and heme proteins such as cyclooxygenase. It is well known that the reactions of NO in the vasculature are O(2) dependent, but this has not been addressed in most studies designed to elucidate the role of H(2)S in vascular function. This is important, since H(2)S reactions can be dramatically altered by the high concentrations of O(2) used in cell culture and organ bath experiments. To test the hypothesis that the effects of H(2)S on the vasculature are O(2) dependent, we have measured real-time levels of H(2)S and O(2) in respirometry and vessel tension experiments, as well as the associated vascular responses. A novel polarographic H(2)S sensor developed in our laboratory was used to measure H(2)S levels. Here we report that, in rat aorta, H(2)S concentrations that mediate rapid contraction at high O(2) levels cause rapid relaxation at lower physiological O(2) levels. At high O(2), the vasoconstrictive effect of H(2)S suggests that it may not be H(2)S per se but, rather, a putative vasoactive oxidation product that mediates constriction. These data are interpreted in terms of the potential for H(2)S to modulate vascular tone in vivo.     

Drosophila neuroglian: a member of the immunoglobulin superfamily with extensive homology to the vertebrate neural adhesion molecule L1

Drosophila neuroglian is an integral membrane glycoprotein that is expressed on a variety of cell types in the Drosophila embryo, including expression on a large subset of glial and neuronal cell bodies in the central and peripheral nervous systems and on the fasciculating axons that extend along them. Neuroglian cDNA clones were isolated by expression cloning. cDNA sequence analysis reveals that neuroglian is a member of the immunoglobulin superfamily. The extracellular portion of the protein consists of six immunoglobulin C2-type domains followed by five fibronectin type III domains. Neuroglian is closely related to the immunoglobulin-like vertebrate neural adhesion molecules and, among them, shows most extensive homology to mouse L1. Its homology to L1 and its embryonic localization suggest that neuroglian may play a role in neural and glial cell adhesion in the developing Drosophila embryo. We report here on the identification of a lethal mutation in the neuroglian gene.     

Helix packing moments reveal diversity and conservation in membrane protein structure

Helical membrane proteins are more tightly packed and the packing interactions are more diverse than those found in helical soluble proteins. Based on a linear correlation between amino acid packing values and interhelical propensity, we propose the concept of a helix packing moment to predict the orientation of helices in helical membrane proteins and membrane protein complexes. We show that the helix packing moment correlates with the helix interfaces of helix dimers of single pass membrane proteins of known structure. Helix packing moments are also shown to help identify the packing interfaces in membrane proteins with multiple transmembrane helices, where a single helix can have multiple contact surfaces. Analyses are described on class A G protein-coupled receptors (GPCRs) with seven transmembrane helices. We show that the helix packing moments are conserved across the class A family of GPCRs and correspond to key structural contacts in rhodopsin. These contacts are distinct from the highly conserved signature motifs of GPCRs and have not previously been recognized. The specific amino acid types involved in these contacts, however, are not necessarily conserved between subfamilies of GPCRs, indicating that the same protein architecture can be supported by a diverse set of interactions. In GPCRs, as well as membrane channels and transporters, amino acid residues with small side-chains (Gly, Ala, Ser, Cys) allow tight helix packing by mediating strong van der Waals interactions between helices. Closely packed helices, in turn, facilitate interhelical hydrogen bonding of both weakly polar (Ser, Thr, Cys) and strongly polar (Asn, Gln, Glu, Asp, His, Arg, Lys) amino acid residues. We propose the use of the helix packing moment as a complementary tool to the helical hydrophobic moment in the analysis of transmembrane sequences.     

Covalent carcinogenic O6-methylguanosine lesions in DNA. Structural studies of the O6 meG X A and O6meG X G interactions in dodecanucleotide duplexes

High-resolution proton and phosphorus nuclear magnetic resonance studies are reported on the self-complementary d(C1-G2-N3-G4-A5-A6-T7-T8-C9-O6meG10-C11-G12) duplexes (henceforth called O6meG X A 12-mer when N3 = A3 and O6meG X G 12-mer when N3 = G3), which contain symmetry-related A3 X O6meG10 and G3 X O6meG10 interactions in the interior of the helices. We observe inter-base-pair nuclear Overhauser effects (NOE) between the base protons at the N3 X O6meG10 modification site and protons of flanking G2 X C11 and G4 X C9 base-pairs, indicative of the stacking of N3 and O6meG10 bases in both O6meG X A 12-mer and O6meG X G 12-mer duplexes. We have assigned all the base and a majority of the sugar protons from two-dimensional proton-correlated and nuclear Overhauser effect experiments on the O6meG X A 12-mer duplex and O6meG X G 12-mer duplex in solution. The observed NOEs establish that the A3 and O6meG10 at the modification site and all other residues adopt the anti configuration about the glycosidic bond, and that the O6meG X A 12-mer forms a right-handed duplex. The interaction between the bulky purine A3 and O6meG10 residues in the anti orientation results in large proton chemical shift perturbations at the (G2-A3-G4) X (C9-O6meG10-C11) segments of the helix. By contrast, we demonstrate that the O6meG10 residue adopts a syn configuration, while all other bases adopt an anti configuration about the glycosidic bond in the right-handed O6meG X G 12-mer duplex. This results in altered NOE patterns between the base protons of O6meG10 and the base and sugar protons of flanking C9 and C11 residues in the O6meG X G 12-mer duplex. The phosphorus backbone is perturbed at the modification site in both duplexes, since the phosphorus resonances are dispersed over 2 parts per million in the O6meG X A 12-mer and over 1 part per million in the O6meG X G 12-mer compared to a 0.5 part per million dispersion for an unperturbed DNA helix. We propose tentative pairing schemes for the A3 X O6meG10 and G3 X O6meG10 interactions in the above dodecanucleotide duplexes.     

Life cycle energy and GHG emissions of PET recycling: change-oriented effects

Purpose  

The demand of PET bottles has increased rapidly in the past decades. The purpose of this study is to understand the environmental impact of PET recycling system, in which used bottles are recycled into both fibre and bottles, and to compare the recycling system with single-use PET.     

Patterning of the branched head appendages in Schistocerca americana and Tribolium castaneum

Much of our understanding of arthropod limb development comes from studies on the leg imaginal disc of Drosophila melanogaster. The fly limb is a relatively simple unbranched (uniramous) structure extending out from the body wall. The molecular basis for this outgrowth involves the overlap of two signaling molecules, Decapentaplegic (Dpp) and Wingless (Wg), to create a single domain of distal outgrowth, clearly depicted by the expression of the Distal-less gene (Dll). The expression of wg and dpp during the development of other arthropod thoracic limbs indicates that these pathways might be conserved across arthropods for uniramous limb development. The appendages of crustaceans and the gnathal appendages of insects, however, exhibit a diverse array of morphologies, ranging from those with no distal elements, such as the mandible, to appendages with multiple distal elements. Examples of the latter group include branched appendages or those that possess multiple lobes; such complex morphologies are seen for many crustacean limbs as well as the maxillary and labial appendages of many insects. It is unclear how, if at all, the known patterning genes for making a uniramous limb might be deployed to generate these diverse appendage forms. Experiments in Drosophila have shown that by forcing ectopic overlaps of Wg and Dpp signaling it is possible to generate artificially branched legs. To test whether naturally branched appendages form in a similar manner, we detailed the expression patterns of wg, dpp, and Dll in the development of the branched gnathal appendages of the grasshopper, Schistocerca americana, and the flour beetle, Tribolium castaneum. We find that the branches of the gnathal appendages are not specified through the redeployment of the Wg-Dpp system for distal outgrowth, but our comparative studies do suggest a role for Dpp in forming furrows between tissues.     

Stereoselective enzymatic hydrolysis of (exo,exo)-7-oxabicyclo[2.2.1]heptane-2,3-dimethanol diacetate ester in a biphasic system

Summary A key chiral intermediate lactol(3)[3aS (3a,4,7,7a)]-hexahydro-4,7-epoxy-isobenzofuran-1 (3H)-one was prepared for the total synthesis of a new thromboxane antagonist. The stereoselective hydrolysis of (exo,exo)-7-oxabicyclo[2.2.1]heptane-2,3-dimethanol, diacetate ester (1) to the corresponding chiral monoacetate ester (2) was carried out with lipases, among which Amano P-30 lipase from Pseudomonas sp. was most effective since it gave the desired enantiomer of monoacetate ester. A yield of 75 mol% and optical purity of >99% was obtained when the reaction was conducted in a biphasic system with 10% toluene at 5 g/l of the substrate. Lipase P-30 was immobilized on Accurel polypropylene (PP) and the immobilized enzyme was reused (five cycles) without loss of enzyme activity, productivity or optical purity. The reaction process was scaled-up to 80 1 (400 g substrate) and monoacetate (2) was isolated in 80 mol% yield with 99.3% optical purity as determined by chiral HPLC and nuclear magnetic resonance (NMR) analysis. A gas chromatography of 99.5% and specific rotation, []_D of -7.6° was obtained. The chiral monoacetate ester (2) was oxidized to its corresponding aldehyde and subsequently hydrolyzed to give lactol (3).     

Nitrosothiol Formation and Protection against Fenton Chemistry by Nitric Oxide-induced Dinitrosyliron Complex Formation from Anoxia-initiated Cellular Chelatable Iron Increase

Dinitrosyliron complexes (DNIC) have been found in a variety of pathological settings associated with ^•NO. However, the iron source of cellular DNIC is unknown. Previous studies on this question using prolonged ^•NO exposure could be misleading due to the movement of intracellular iron among different sources. We here report that brief ^•NO exposure results in only barely detectable DNIC, but levels increase dramatically after 1–2 h of anoxia. This increase is similar quantitatively and temporally with increases in the chelatable iron, and brief ^•NO treatment prevents detection of this anoxia-induced increased chelatable iron by deferoxamine. DNIC formation is so rapid that it is limited by the availability of ^•NO and chelatable iron. We utilize this ability to selectively manipulate cellular chelatable iron levels and provide evidence for two cellular functions of endogenous DNIC formation, protection against anoxia-induced reactive oxygen chemistry from the Fenton reaction and formation by transnitrosation of protein nitrosothiols (RSNO). The levels of RSNO under these high chelatable iron levels are comparable with DNIC levels and suggest that under these conditions, both DNIC and RSNO are the most abundant cellular adducts of ^•NO.