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.     

Evidence from mutation spectra that the UV hypermutability of xeroderma pigmentosum variant cells reflects abnormal, error-prone replication on a template containing photoproducts.

Xeroderma pigmentosum (XP) variant patients are genetically predisposed to sunlight-induced skin cancer. Fibroblasts derived from these patients are extremely sensitive to the mutagenic effect of UV radiation and are abnormally slow in replicating DNA containing UV-induced photoproducts. However, unlike cells from the majority of XP patients, XP variant cells have a normal or nearly normal rate of nucleotide excision repair of such damage. To determine whether their UV hypermutability reflected a slower rate of excision of photoproducts specifically during early S phase when the target gene for mutations, i.e., the hypoxanthine (guanine) phosphoribosyltransferase gene (HPRT), is replicated, we synchronized diploid populations of normal and XP variant fibroblasts, irradiated them in early S phase, and compared the rate of loss of cyclobutane pyrimidine dimers and 6-4 pyrimidine-pyrimidones from DNA during S phase. There was no difference. Both removed 94% of the 6-4 pyrimidine-pyrimidones within 8 h and 40% of the dimers within 11 h. There was also no difference between the two cell lines in the rate of repair during G1 phase. To determine whether the hypermutability resulted from abnormal error-prone replication of DNA containing photoproducts, we determined the spectra of mutations induced in the coding region of the HPRT gene of XP variant cells irradiated in early S and G1 phases and compared with those found in normal cells. The majority of the mutations in both types of cells were base substitutions, but the two types of cells differed significantly from each other in the kinds of substitutions, but the two types differed significantly from each other in the kinds of substitutions observed either in mutants from S phase (P < 0.01) or from G1 phase (P = 0.03). In the variant cells, the substitutions were mainly transversions (58% in S, 73% in G1). In the normal cells irradiated in S, the majority of the substitutions were G.C --> A.T, and most involved CC photoproducts in the transcribed strand. In the variant cells irradiated in S, substitutions involving cytosine in the transcribed strand were G.C --> T.A transversions exclusively. G.C --> A.T transitions made up a much smaller fraction of the substitutions than in normal cells (P < 0.02), and all of them involved photoproducts located in the nontranscribed strand. The data strongly suggest that XP variant cells are much less likely than normal cells to incorporate either dAMP or dGMP opposite the pyrimidines involved in photoproducts. This would account for their significantly higher frequency of mutants and might explain their abnormal delay in replicating a UV-damaged template.     

Biological control of citrus whiteflyDialeurodes citri ashmead [Hom.: Aleyrodidae] usingEncarsia lahorensis howard [Hym.: Apheunidae] in countries of the former ussr

The citrus whiteflyDialeurodes citri Ashmead is one of the most important insect pests of citrus groves on the Black Sea coast of the Caucasus and on the Caspian Sea coast of the Talysh Mountains; it is the most important citrus pest of trench cultivation in Central Asia and in glasshouses. The parasitoidEncarsia lahorensis Howard was introduced in 1983 into Russia (Moscow) from Pakistan. It was reared in a laboratory of the All-Russian Plant Quarantine Institute. The parasitoid was released as follows: in 1985 in Adzharia (Batumi); in 1987 in a glasshouse in Russia (near Moscow) and in 1988-1990 in Central Asia - Uzbekistan (Namangan) and other regions. It established well in all places of release. The rate of parasitization ofD. citri byE. lahorensis reached 50–52% in the orchard in Batumi five years after the first release, 56–60% in the glasshouse in Moscow three years after the first release, and 50% in trenches in Namangan two years after the first release. Levels of the pest populations decreased dramatically in the glasshouse and trenches. The efficiency of the additional feeding ofE. lahorensis adults on the host larvae was evaluated to 26 to 60%. The differences between populations of the parasitoid in the three different areas are discussed.     

Recognition of 29 kDa surface-associated adhesive molecule of Entamoeba histolytica by monoclonal antibodies

Abstract Monoclonal antibodies have been developed and used as specific probe to locate and identify a 29-kDa molecule of axenic Entamoeba histolytica trophozoites. Monoclonal antibody produced by clone C8 (MoAb C8) strongly agglutinated the amoebic trophozoites. THe immunofluorescence of live E. histolytica trophozoites and surface fluorescence of acetone-fixed trophozoites by MoAb C8 indicated existence of a 29-kDa molecule on surface-associated plasma membrane of E. histolytica . The monoclonal antibody belonged to IgG₁ isotype. The prior treatment of E. histolytica trophozoites with MoAb C8 resulted in significant ( P < 0.01) reduction in adherence of amoebic trophozoites to cultured Chinese Hamster Ovary cells and significant ( P < 0.01) reduction in cytotoxicity to cultured Baby Hamster Kidney cells. Pretreatment of amoebic trophozoites with MoAb C8 prior to cultivation in TPS-1 medium resulted in significant ( P < 0.01) reduction in growth of the parasite. Thus, the data suggested that the surface-exposed 29-kDa molecule may be one of the receptors involved in E. histolytica host cell interactions and may possibly modulate amoebic disease processes.     

The Effects of Severe Hypobaric Hypoxia and Inhibition of Hypoxia-Inducible Factor-1 (HIF-1) on Biomarkers of Cardiac and Skeletal Muscle Injury in Rats

Biophysics - Abstract—The goal of the present study was to investigate the molecular mechanisms that underlie heart and skeletal muscle damage in male Wistar rats weighing 200–250 g in...     

Photogeneration of NADH under coupled action of CdS semiconductor and hydrogenase from Alcaligenes eutrophus without exogenous mediators.

Photoreduction of NAD has been accomplished by a system consisting of the NAD-dependent hydrogenase from Alcaligenes eutrophus immobilized on CdS particles with formate as artificial electron donor. Enzymatically active NADH is formed under illumination of this system by visible light. Accumulation of the coenzyme dimer (NAD)2 was not detected. NAD photoreduction is supposed to proceed via the direct electron transfer from the semiconductor to the enzyme electron transport chain. However, NADH formation as a result of hydrogenase interaction with anion-radicals (CO2.-) formed in the course of formate photooxidation cannot at present be excluded.     

Some components of the air spora in Jamaica and their possible medical application

A knowledge of the pollen and fungal spores which comprise the air spora is useful as a preliminary approach to the problem of respiratory allergy. Therefore, this study of the qualitative and quantitative aspects of the air spora was done. Fungal spores were found to be numerically dominant, comprising 97.73% whilst pollen comprised 0.40% of the total material observed. A small number of types made up the majority of the fungal air spora, namely, Cladosporium, the Sporobolomycetaceae group, Diatrype, Glomerella, hyaline and coloured basidiospores, and septate fusiform spores. Seasonal periodicity studies on twenty-five fungal types showed that a high number of spores were trapped for sixteen during wet months, four during cooler months, and that five showed no seasonal trends. Mean diurnal periodicity studies for the year on the same twenty-five spore types showed that all had a maximum number of spores trapped at some time during the day. Investigation of the effect of rainfall on the numbers of spores released showed that the amount and duration of rainfall, the time of day rain occurs, and the length of the dry period preceding rain were of varying importance to particular spore types.     

Beat Processing Is Pre-Attentive for Metrically Simple Rhythms with Clear Accents: An ERP Study

The perception of a regular beat is fundamental to music processing. Here we examine whether the detection of a regular beat is pre-attentive for metrically simple, acoustically varying stimuli using the mismatch negativity (MMN), an ERP response elicited by violations of acoustic regularity irrespective of whether subjects are attending to the stimuli. Both musicians and non-musicians were presented with a varying rhythm with a clear accent structure in which occasionally a sound was omitted. We compared the MMN response to the omission of identical sounds in different metrical positions. Most importantly, we found that omissions in strong metrical positions, on the beat, elicited higher amplitude MMN responses than omissions in weak metrical positions, not on the beat. This suggests that the detection of a beat is pre-attentive when highly beat inducing stimuli are used. No effects of musical expertise were found. Our results suggest that for metrically simple rhythms with clear accents beat processing does not require attention or musical expertise. In addition, we discuss how the use of acoustically varying stimuli may influence ERP results when studying beat processing.     

Microcin C: Biosynthesis,Mode of Action,and Potential as a Lead in Antibiotics Development

The natural compound Microcin C (McC) is a Trojan horse inhibitor of aspartyl tRNA synthetases endowed with strong antibacterial properties, in which a heptapeptide moiety is responsible for active transport of the inhibitory metabolite part into the bacterial cell. The intracellularly formed aspartyl AMP analogue carries a chemically more stable phosphoramidate linkage, in comparison to the labile aspartyl-adenylate, and in addition is esterified with a 3-aminopropyl moiety. Therefore, this compound can target aspartyl-tRNA synthetase. The biochemical production and secretion of McC, and the possibilities to develop new classes of antibiotics using the McC Trojan horse concept in combination with sulfamoylated adenosine analogues will be discussed briefly.