UDP-Gal: <Emphasis Type="Italic">N</Emphasis>-acetylglucosamine β 1–4 galactosyltransferase expressing live attenuated parasites as vaccine for visceral leishmaniasis

As compared to cutaneous leishmaniasis, vaccination against visceral leishmaniasis (VL) has received limited attention. In this study, we demonstrate for the first time that an UDP-Galactose: N-acetylglucosamine β 1–4 galactosyltransferase (GenBank Accession No. EF159943) expressing attenuated LD clonal population (A-LD) is able to confer protection against the experimental challenge with the virulent LD AG83 parasite. A-LD was also effective in established leishmania infection. The vaccinated animals showed both cell mediated (in vitro T-cell proliferation, and DTH response) and humoral responses (Th1 type). These results demonstrate the potential of the attenuated clones as an immunotherapeutic and immunoprophylactic agent against visceral leishmaniasis.     

Evaluation of early generations for iron chlorosis in relation to productivity in groundnut (Arachis hypogaea L.)

Five popular but iron-inefficient cultivars were crossed with three efficient genotypes and both parents and F₁s were evaluated for iron-efficiency in potted calcareous and noncalcareous soil. The iron-efficient genotypes were dark green or green in both noncalcareous and calcareous soils whereas inefficient types were light green to yellow in calcareous soil. The chlorophyll and active iron (Fe²⁺) concentration of leaves was less in iron-efficient genotypes compared to efficient types in calcareous soil and reduction of both the parameters from noncalcareous to calcareous soil was considerably high in iron-inefficient lines. There was significant correlation between visual scores, chlorophyll and active iron content. There were no differences among F₁s for iron chlorosis and they were all iron-inefficient. The frequency of iron-inefficient plants was higher than the efficient plants in all F₂ populations. But most of the productive plants came from iron-efficient segregants indicating strong association between iron-efficiency and productivity. Based on the results selection for iron-efficiency in early generations and extensive evaluation for productivity in advanced generations is suggested for developing varieties for cultivation in calcareous soils.     

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.     

Short-term and long-term effects of brown and black masheri (pyrolysed tobacco product) on vitamin A and vitamin C levels in mice and hamsters

The short-term and long-term effects of two most commonly used brown and black masheri were studied in Swiss mice and Syrian golden hamsters. In short-term studies, both the types of masheri extracts (ME) at 3/4 LD50 dose given ip did not have any effect on either liver or plasma vitamin C levels (both species). However, a decrease in liver vitamin A was observed only in hamsters injected with black ME. Similar effect was not observed in mice injected with both the types of masheri extracts. In long-term studies, when both the types of masheri were fed through diet at 10% level for 20 months, no effect was observed on hepatic or plasma vitamin C levels in mice (both sexes), while an increase in vitamin C levels was observed in black masheri diet fed hamsters. A depletion in liver vitamin A was observed in hamsters fed both the types of masheri. Such an effect was observed only in black masheri diet fed Swiss mice (both sexes) and brown masheri diet fed Swiss females.     

Search for chromosomal variations among gas-exposed persons in Bhopal

Summary A chromosomal survey using standard lymphocyte cultures employing different media and G-banding techniques was initiated in 1984. This study became particularly important following the tragic gaseous exposure of the population in Bhopal at midnight on 2 December 1984. We have been able to formulate a chromosomal profile for each person whom we have studied; during 1986–1988, 154 persons were examined twice. Among seemingly normal individuals, as many as 20% might possess some chromosomal abnormality; of these, 50% may develop, at a later date, some kind of pathological complication (such as tumours, recurrent abortion or transmission of defects to their offspring). The people exposed to methyl isocyanate have repeatedly shown Robertsonian translocations, mostly in acrocentric chromosomes 13 and 21. Other types of translocations have been studied among all exposed (53) and normal (101) persons; the involvement of chromosomes 5, 9, 11, 14 and 16 is statistically significant (P= <0.001). One of the major clinical symptoms is dyspnoea; we have estimated that almost all seriously dyspnoeic patients have developed at least two categories of chromosomal aberrations, one of which is Robertsonian translocation, in at least 10% metaphases. Our chromosomal survey will be of significance because we are able to identify people with chromosomal aberrations that might be correlated with future pathological consequences of the accident. The chromosomal load that can be sustained with an apparently normal phenotype can also be measured.     

Retinopetal neuronal system in the brain of an air-breathing teleost fish,Channa punctata

Summary Retinopetal neurons were visualised in the telencephalon and diencephalon of an air-breathing teleost fish, Channa punctata, following administration of cobaltous lysine to the optic nerve. The labelled perikarya (n=45–50) were always located on the side contralateral to the optic nerve that had received the neuronal tracer. The rostral-most back-filled cell bodies were located in the nucleus olfactoretinalis at the junction between the olfactory bulb and the telencephalon. In the area ventralis telencephali, two groups of telencephaloretinopetal neurons were identified near the ventral margin of the telencephalon. The rostral hypothalamus exhibited retrogradely labelled cells in three discrete areas of the lateral preoptic area, which was bordered medially by the nucleus praeopticus periventricularis and nucleus praeopticus, and laterally by the lateral forebrain bundle. In addition to a dorsal and a ventral group, a third population of neurons was located ventral to the lateral forebrain bundle adjacent to the optic tract. The dorsal group of neurons exhibited extensive collaterals; a few extended laterally towards the lateral forebrain bundle, whereas others ran into the dorsocentral area of the area dorsalis telencephali. A few processes extended via the anterior commissure into the telencephalon ipsilateral to the optic nerve that had been exposed to cobaltous lysine. However, the ventral cell group did not possess collaterals. In the diencephalon, retinopetal cells were visualised in the nucleus opticus dorsolateralis located in the pretectal area; these were the largest retinopetal perikarya of the brain. The caudal-most nucleus that possessed labelled somata was the retinothalamic nucleus; it contained the largest number of retinopetal cells. The limited number of widely distributed neurons in the forebrain, some with extensive collaterals, might participate in functional integration of different brain areas involved in feeding, which in this species is influenced largely by taste, not solely by vision.     

The Dissonance Mutant of Courtship Song in Drosophila Melanogaster: Isolation, Behavior and Cytogenetics

The dissonance mutant of courtship song was induced by chemical mutagenesis. This X-chromosomal mutation causes the D. melanogaster male's acoustical output, resulting from his wing vibrations directed at a female, to include very long and loud tone "pulses." Yet, a given train of pulses starts out as normal, with the signals in all but the shortest singing bouts eventually becoming polycyclic and high-amplitude. The aberrant songs caused by diss (map position, 1-52; cytological interval, 14C1-2 to 14C4-5) were quantitatively compared to those produced by mutant cacophony males, whose pulses are much more uniformly polycyclic (due to a mutation mapping elsewhere on the X chromosome). Males or females expressing diss are normal in several "general" behaviors. Yet diss males not only sing abnormally, but they also exhibit longer-than-normal mating latencies in their courtship of females. These decrements seem to be associated, at least in part, with visually aberrant behavior of diss flies--measured with regard to male courtship per se, and also in tests of more general visual responses. Such defects were found when testing diss males or females, and the genetic etiology of the visual impairments were provisionally mapped to the same locus to which the song abnormality has been localized. Neurogenetic connections between the control of courtship singing behavior and visual system functions are discussed with respect to the new song mutation (diss) and the older one (cac)--which also turned out to be genetically related to a mutation that causes abnormalities of light-induced behavior and physiology.     

DNA damage and repair in epithelial (mucous) cells and crypt cells from isolated colon

Colon epithelium is made up of two general classes of cells, surface cells which are post-mitotic and crypt cells which contain the proliferative population. Their relative vulnerability to environmental damage and ability to perform DNA repair are important issues in colon carcinogenesis. DNA damage and repair was studied by the nucleoid sedimentation method in freshly isolated crypt cells for comparison with previous studies of post-mitotic surface epithelial cells. Suspensions of crypt cells were isolated from preparations of mouse colon by a series of sequential incubations in buffer containing 1.5 mM EDTA. Treatment of crypt cells for 30 min with 1.2 X 10(-6) M methyl methane sulfonate (MMS), photoaffinity labeling with 1 X 10(-6) M ethidium monoazide, lithocholic acid (2.5 X 10(-4) M) treatment for 1 h or X-irradiation at 1500 rads resulted in single-strand breaks in the DNA, which were repaired after 2 h of additional incubation. Interestingly, X-rays at 1000 rads and lithocholic acid (LA) (2.5 X 10(-6) M) after 30 min incubation failed to produce the detectable shift in nucleoid sedimentation characteristic of single-strand breaks, perhaps due to rapid repair by these proliferative cells. UV-irradiation failed to provoke strand incision as was also observed for the superficial post-mitotic cells in the previous studies. These studies showed the feasibility of studying DNA damage and repair processes in these two classes of colon epithelial cells in response to specific carcinogenic insult.