A new species of Eriocaulon (Eriocaulaceae) from Madhya Pradesh, India

Eriocaulon raipurense (Eriocaulaceae) is described and illustrated as a new species from Madhya Pradesh, India. The species is closely allied to E. hamiltonianum but differs in the size and apex of involucral bancts, white-pilose nature of floral bracts and colour of female petals.     

Nif-hybrids of Enterobacter: selection for nif gene integration with chlorate

The nif gene group from Klebsiella can be transferred into Enterobacter cloacae by conjugation using Escherichia coli donor cells carrying the composite self-transmissible nif-plasmid pRD1. A small fraction of the hybrids obtained is stable upon prolonged passaging without selection. Their stability is due to integration of pRD1 into the chromosome. Such integration hybrids were chlorate resistant, and nitrate reductase negative, which indicated that integration preferentially occurred within one of the genes for the production or functioning of this enzyme. Chlorate resistance could, therefore, be used to select for additional nitrate reductase-negative sublines with pRD1 in their chromosome. Such sublines have been analyzed further for the presence of nif genes, other pRD1 markers, and for stability. In all except one the complete plasmid seems to have been integrated. Some tend to revert to nitrate utilisation (chlorate sensitivity).     

Transcriptional regulation of the antioxidant protein 2 gene, a thiol-specific antioxidant, by lens epithelium-derived growth factor to protect cells from oxidative stress.

Antioxidant protein 2 (AOP2), a member of the newly defined family of thiol-specific antioxidant proteins, has been shown to remove H(2)O(2) and protect proteins and DNA from oxidative stress. Here we report that LEDGF is one of the regulatory factors for the AOP2 gene. We found that LEDGF bound to the heat shock element and to stress-related elements in the AOP2 promoter. It trans-activated expression of AOP2-CAT in COS-7 cells and lens epithelial cells overexpressing LEDGF. Mutations in the heat shock element and stress-related elements of the AOP2 promoter reduced LEDGF-dependent trans-activation. Lens epithelial cells showed a higher level of AOP2 mRNA in the presence of LEDGF. Cells overexpressing LEDGF exhibited a higher level of AOP2 protein, the level of which was directly related to the increase in cellular protection. Thus, LEDGF, by activating the AOP2 gene, protected and enhanced the survival of cells under oxidative stress.     

Laboratory Estimation of Field Resistance of Potato to Late Blight

Based on quantitative measurement of components of field resistance of potatoes to late blight, a multiple linear regression equation is derived for laboratory estimation of Area Under Disease Progress Curve. The equation accounts for 82% of variation in Area Under Disease Progress Curve. Transformation of data or inclusion of more terms do not improve the equation significantly. The method is suggested as a replacement or supplement to field testing.     

Role of Melanin in Release of Extracellular Enzymes and Selection of Aggressive Isolates of Bipolaris sorokiniana in Barley

Eighteen barley isolates of Bipolaris sorokiniana belonging to wild and clonal type of black, mixed and white subpopulations were quantitatively assayed for their melanin content and aggressiveness with respect to production of some of the extracellular enzymes such as cellulase, pectinase, amylase and protease. Cellulase and pectinase constituted major portion of the enzymes recovered from the black, mixed and white isolates. Enzyme production and aggressiveness were relatively higher in melanin devoid or low melanin isolates. The melanin deficient isolates were also differentiated from black and mixed isolates on the basis of variation in internal transcribed spacer region of the ribosomal DNA. Higher enzyme productions positively correlated with area under disease progress curve (AUDPC) and lesion development. Melanin content was negatively correlated with extracellular enzymes and aggressiveness of the isolates. Based on melanin content, lesion size, AUDPC and extracellular enzymes, the isolates were grouped in two major clusters (I and II) with further division of cluster II into two sub-clusters (II-A and II-B). The results appears to indicate a possible role of melanin in release of extracellular enzymes and hence in evolution and selection of aggressive isolates of B. sorokiniana in barley.     

Roles of Subunit NuoK (ND4L) in the Energy-transducing Mechanism of Escherichia coli NDH-1 (NADH:Quinone Oxidoreductase)

The bacterial H⁺-translocating NADH:quinone oxidoreductase (NDH-1) catalyzes electron transfer from NADH to quinone coupled with proton pumping across the cytoplasmic membrane. The NuoK subunit (counterpart of the mitochondrial ND4L subunit) is one of the seven hydrophobic subunits in the membrane domain and bears three transmembrane segments (TM1–3). Two glutamic residues located in the adjacent transmembrane helices of NuoK are important for the energy coupled activity of NDH-1. In particular, mutation of the highly conserved carboxyl residue (_KGlu-36 in TM2) to Ala led to a complete loss of the NDH-1 activities. Mutation of the second conserved carboxyl residue (_KGlu-72 in TM3) moderately reduced the activities. To clarify the contribution of NuoK to the mechanism of proton translocation, we relocated these two conserved residues. When we shifted _KGlu-36 along TM2 to positions 32, 38, 39, and 40, the mutants largely retained energy transducing NDH-1 activities. According to the recent structural information, these positions are located in the vicinity of _KGlu-36, present in the same helix phase, in an immediately before and after helix turn. In an earlier study, a double mutation of two arginine residues located in a short cytoplasmic loop between TM1 and TM2 (loop-1) showed a drastic effect on energy transducing activities. Therefore, the importance of this cytosolic loop of NuoK (_KArg-25, _KArg-26, and _KAsn-27) for the energy transducing activities was extensively studied. The probable roles of subunit NuoK in the energy transducing mechanism of NDH-1 are discussed.     

Preliminary X-ray investigation of a bifunctional inhibitor from Indian finger millet (ragi).

A bifunctional alpha-amylase/trypsin inhibitor that has two binding sites has been purified from ragi. The inhibitor has been crystallized from its ammonium sulphate solution by the vapour diffusion method. The crystals belong to the orthogonal space group P2(1)2(1)2(1) with unit cell dimensions a = 30.49 A, b = 56.30 A, c = 73.65 A and Z = 4.     

Life cycle changes during 12 successive generations of laboratory colonisation of the leafroller Cnephasia jactatana (Walker) (Lepidoptera: Tortricidae) on artificial diet

Abstract

Close monitoring of the lepidopteran leafroller Cnephasia jactatana under laboratory colonisation revealed few distinct effects of successive rearing on artificial diet on the life cycle. The second laboratory generation had a prolonged development time and altered sex synchronism in pupation and eclosion patterns. Some deleterious changes were observed in later generations, including decreases in fertility, egg hatch and sperm motility, failure of mating adults to separate, and pupal and adult malformations. These changes were not adaptive, but were due to incompatibility with the general purpose diet (GPD) used; they were absent under sub-colonisation on a sheepnut-bean based diet (SBD). Success in the laboratory colonisation of C. jactatana is attributed to a random mating protocol, choice of environmental conditions representing the wild habitat, and a rapid rate of population growth.