Effect of soil matric potential,method of irrigation and nitrogen fertilization on yield,quality, nutrient uptake and water use of radish (Raphanus sativus L.)

Summary Field experiments carried out at the Indian Institute of Horticultural Research, Bangalore during 1983 and 1984 on radish indicated that frequent irrigations when soil matric potential reached –20 kPa at 18 cm depth resulted in maximum root yield, lower NO₃-N content in roots, higher N, P, K, Ca and WUE of radish.Contribution No. 63/86 from Indian Institute of Horticultural Research, Bangalore, India     

A fluoroquinolone resistance protein from Mycobacterium tuberculosis that mimics DNA

Fluoroquinolones are gaining increasing importance in the treatment of tuberculosis. The expression of MfpA, a member of the pentapeptide repeat family of proteins from Mycobacterium tuberculosis, causes resistance to ciprofloxacin and sparfloxacin. This protein binds to DNA gyrase and inhibits its activity. Its three-dimensional structure reveals a fold, which we have named the right-handed quadrilateral beta helix, that exhibits size, shape, and electrostatic similarity to B-form DNA. This represents a form of DNA mimicry and explains both its inhibitory effect on DNA gyrase and fluoroquinolone resistance resulting from the protein's expression in vivo.     

A Study of Krebs Citric Acid Cycle Enzymes in Rice Larvae (Corcyrace phalonica St) During Mycotoxicosis

Krebs citric acid cycle enzymes have been studied in rice moth larvae (Corcyra cephalonica St) reared in groundnut meal control and contaminated with A. flavus, wheat bran control and wheat bran contaminated with A. flavus and also wheat bran containing aflatoxin. It was observed that the activity of enzymes other than succinic oxidase, succinic dehydrogenase and isocitric dehydrogenase were reduced significantly in larvae reared in contaminated groundnut meal when compared with the control. In the case of larvae reared in contaminated wheat bran all the enzymes except succinic oxidase were inhibited when compared to the control larvae. It was also observed that the inhibition of these enzymes is greater in the case of larvae reared in contaminated wheat bran than in contaminated groundnut meal. The higher toxicity of wheat bran has been discussed.     

Discovery of a sooty mould scavenging beetle, <Emphasis Type="Italic">Leiochrinus nilgirianus</Emphasis> Kaszab (Coleoptera: Tenebrionidae) on coconut palms infested by the invasive rugose spiralling whitefly, <Emphasis Type="Italic">Aleurodicus rugioperculatus</Emphasis> Martin (Hemiptera: Aleyrodidae)

Scavenging action of Leiochrinus nilgirianus Kaszab (Coleoptera: Tenebrionidae) on sooty mould deposition on coconut palms due to heavy honeydew production by the invasive rugose spiralling whitefly, Aleurodicus rugioperculatus Martin (Hemiptera: Aleyrodidae), is reported for the first time from Kerala, India. Adult beetles, averaging 2.07?±?0.9 / leaflet, with a maximum of five beetles per leaflet, and immature stages were generally confined to the abaxial of the palm leaves during daytime, but were found feeding on sooty mould during morning hours in damp conditions. The specially aided adaptive leg features of L. nilgirianus with bristle-like hairs on the undersurface of tarsomeres probably aid in proper adhesion on sooty mould laden plant surface and well developed tarsal claws that perhaps assist swift movement on fungus-laden leaflets. On an average one adult beetle could clear 1–2 mm² sooty mould laden area in a period of one minute. In situ habitat conservation of L. nilgirianus would help to reduce the sooty mould at no cost in the most natural and eco-friendly manner avoiding chemical management options and other expensive methods.     

Molecular evidence supports hypervariability in Phytophthora colocasiae associated with leaf blight of taro

The oomycete Phytophthora colocasiae that causes taro leaf blight is the most devastating disease of taro and is widely distributed worldwide. Molecular and phenotypic techniques were employed for assessing and exploiting the genetic variability among four populations of P. colocasiae obtained from a fine spatial scale (multiple leaf blight lesions on single taro leaf). Phenotypic characters such as virulence, morphology and mating type showed no variation. ITS characterization revealed detectable polymorphism among isolates of P. colocasiae. The mean number of haplotypes (H), haplotype diversity (HD), nucleotide diversity (π), and nucleotide substitution rate (θ) among analyzed sequences were 6.75, 1.00, 0.069, and 0.088 respectively. High levels of inter and intra specific variation were detected by random amplified polymorphic DNA (RAPD) assays. Moderate genetic diversity (H?=?0.2651) was observed among populations of P. colocasiae. Analysis of molecular variance (AMOVA) confirmed that most of the genetic variability was confined to within a population (63.54 %). The coefficient of genetic differentiation among populations (G _ST ) was 0.2007 and estimates of gene flow (Nm) among populations was 1.991 migrants per generation. Cluster analysis using UPGMA revealed that individuals from the same population failed to cluster in one distinct group. The results of the study reveal considerable genetic diversity among and within populations of P. colocasiae obtained from fine spatial scale. The possible mechanisms and implications of this genetic variation are discussed.     

Determination of Ultra Trace Level of Uranium in Ground Water of Different Geo-Chemical Environment by Adsorptive Stripping Voltammetry

The mineral mobilisation in ground water due to rock water interaction largely depends on the localized subsurface geo-chemical environment. During this work, traces of uranium were measured by adsorptive stripping voltametry (AdSV) in groundwater having various level of dissolved minerals. Experimental solutions were prepared in the laboratory by spiking natural groundwater with standard solutions of major cations (Ca²⁺, Mg²⁺, K⁺), anions (Cl^?1, F^?1, and $ {\text{PO}}^{{3 - }}_{4} $ ), trace metal ions (Cu and Pb) and DOC (Dissolved Organic Carbon). The concentrations of these anions, cations and DOC in subsurface water changes due to changes in the geo-chemical environment at different locations. Experimental results show that major anions do not have any pronounced impact on the analysis of uranium. In the case of cations, only Cu²⁺ shows strong interferences. However addition of 2% Ethylene Diammine Tetra-acetic Acid (EDTA) solution in the ratio of 1:25 removes interference due to copper upto a concentration of <0.2 ppm. Interference with copper was also studied by varying the accumulation potential, pH and concentration of chloroanilic acid. Though no interferences were observed in ground water having dissolved organic carbon (DOC) in the range of 0.01–15 ppm, between 15–16 ppm of DOC, the ability to detect uranium by AdSV decreases sharply. Further, if DOC exceeded 16 ppm it was not possible to do the analysis of uranium by AdSV without destruction of DOC, as DOC is a surface active organic compound and accumulates on Hg electrode preferentially over uranium-chloroanilic complex.     

A Classical Live Attenuated Vaccine for Sheep Pox

A classical live attenuated sheep pox vaccine was prepared using the Ranipet strain of sheep pox virus (SPV) at the 50th passage in a secondary lamb testicular cell system. The TCID50 and RD50 were 10(9.63)/ml and 10(9.51)/ml. respectively. The SID50 of SPV challenge virus was 10(5)/ml. The vaccine was found to have no adverse effects in laboratory animals, and was safe and effective in SPV seronegative lambs. In the field, 660 sheep were vaccinated with an immunizing dose containing 1 x 10(2) TCID50. Randomly selected vaccinated sheep mounted good cell-mediated immunity and humoral responses as measured by glucose utilization test and serum neutralization test, respectively, for the study period of 6 months.