Experimental alterations of the spores of lycopodium clavatum as related to diagenesis

Lycopodium clavatum spores have been heated to different temperatures at atmospheric pressure, at room temperature with 0.5 kbar pressure and at different temperatures with 1 kbar pressure, The effects of heat, pressure, and heat and pressure together on the spore have been examined in detail using different microscope techniques. Effects of some chemicals on these spores have also been observed.It is known that temperature and pressure change the colour of spore and pollen grain walls, mainly the exine (outer wall of the spore). Changes to the intine and the matter present in the cytoplasmic cavity (= inner contents), however, have not been taken into account by very many workers. In most of the previous works the inner contents were extracted before the experimental treatment began.In the present work, unextracted spores are used for the experiments which show two types of alterations of the spores with rising temperature at atmospheric pressure: (1) alteration of the inner contents, i.e. gradual colour change of the inner contents and their ultimate exudation from the spore through the exine at about 300°C; (2) gradual shrinkage of the exine due to the exudation of the inner contents which also causes an overall size reduction of the spore from 200° to 350°C. The exine does not change its colour up to 325°C; and this temperature, its starts to change its colour slowly, amalgamates with other exines of the empty spores, becomes amorphous, and ultimately deteriorates into unidentifiable organic matter.The process of colour change of the inner contents of spores and the general deformation are much slower when the spores are subjected to 1 kbar pressure with rising temperatures. Spores at room temperature with 0.5 kbar pressure show no colour change but only physical deformation.     

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.     

In vitro propagation through axillary bud multiplication in different mulberry genotypes

Axillary buds from 5 genotypes of mulberry belonging to 4 species were cultured on modified MS basal medium. A total of 30 media combinations were tried for all the genotypes. The response of axillary buds and the requirement for growth regulators varied with genotype. In Morus indica BAP (0.25–0.5 mg/l), and in M. alba and M. rotondifolia GA₃ (0.5–1.0 mg/l)were found to induce sprouting. Two genotypes of M. bombycis, namely Schimanochi and Mizusawa, developed healthy shoots on the incorporation of 2,4-D (0.5–1.0 mg/l) and BAP (0.5–2.0 mg/l), respectively. IBA (0.5 mg/l), along with cytokinin/auxin/gibberellin, had no effect on bud growth but helped root induction. Shoots developed from the axillary buds were further multiplied as nodal explants. MS basal medium supplemented with 0.5 mg/l IBA and LS vitamins was found best to produce healthy plantlets in all the genotypes. An average 89% survival was observed on transferring the plantlets to soil.Abbreviations MS Murashige and Skoog (1962) - LS Linsmaier and Skoog (1965) - IBA 3-indole-butyric acid - GA₃ Gibberellic acid - BAP 6-Benzylaminopurine - Kn Kinetin - 2,4-D 2,4-Dichlorophenoxyacetic acid     

Plant regeneration from mesophyll protoplasts of Diplotaxis muralis,a wild crucifer

Mesophyll protoplasts from leaves of aseptically grown shoot tips of Diplotaxis muralis were isolated (6.2–7.1×10⁵ protoplasts/g fresh weight of tissue) using one step enzyme digestion. The protoplasts (71% viability) underwent divisions (4.2+0.1%) on plating in M8PS₂ medium and ultimately formed calli with 0.45+0.03% plating efficiency. Plant regeneration could be achieved both through embryogenesis and organogenesis. The efficiency of plant regeneration through organogenesis was 9 times higher than embryogenesis. Forty eight out of 52 plants regenerated so far from 3 independent experiments were normal with respect to fertility and meiotic chromosomal behavior.Abbreviations BAP 6-benzylaminopurine - GA₃ Gibberellic acid - A Kao and Michayluk, 1981 - KM Kao and Michayluk, 1975 - MK₃ Modified K₃ - M8P Modified 8P - MS Murashige and Skoog, 1962 - NAA 1-naphthalene acetic acid - PE Plating efficiency     

Nature and properties of humic acid prepared from different sources and its effect on nutrient availability

Summary Effect of sources, moisture levels and extractants on extraction, analytical properties, IR-spectra, macromolecular characteristics, interaction with cations and physiological properties of the extracted material (humic acid) were studied. Among the three variables, extractant influenced the degree of humification, IR-spectra, nature and properties of humic acids to a greater extent though the other two had significant contribution. Sodium pyrophosphate found to be an ideal extractant for humic acid. Reduced viscosity of humic acids increased with dilution particularly below 0.1 g/dl and decreased with increasing H⁺ concentration between pH 6.5 and 8.5 irrespective of source, moisture level and extractant. The amount of proton released and drop in initial pH of humic acids on addition of different metal ions indicated formation of mono-, di-hydroxy metal-HA complexes which broke down at pH 8.0 and above. HA-Fe²⁺ and HA-Cu²⁺ complexes were found to be most stable. Humic acids from different sources varied significantly in their effect on available nutrient status of soils though, the latter is main determining factor particularly for calcium and magnesium.     

Ontogeny of human fetal catalase superoxide dismutase and lipid peroxidation: A comparative study

A comparative study on the activity profile of catalase and superoxide dismutase, the two scavenging enzymes, as well as the developmental profile of lipid peroxidation in the human fetal brain, liver and kidney have been done for gestation periods ranging from 12 weeks to 28 weeks and beyond. The activity of the scavenging enzymes increase gradually in_all the tissues with the advancement of pregnancy. Brain is an exception in case of catalase where the activity remains more or less same throughout the developmental period except in the case of fetuses, 28 weeks and above where significant decrease in the catalase activity is observed. A high level of lipid peroxidation is observed during early stages of development which declines thereafter.     

Steroid hormones and embryo development in ovariectomized hamsters

Preimplantation embryo development was arrested at the premorula stage in hamsters ovariectomized on Day 1 of pregnancy. This effect was reversed when 500 micrograms progesterone were administered daily. Oestradiol-17 beta given alone had no significant effect on the cleavage rate or blastocyst formation, but a synergistic response was evident when a suboptimal (30 micrograms) dose of progesterone was given with 50 ng oestradiol-17 beta. Cholesterol and hydrocortisol had no effect on embryo development.