Thermal stress and physiological strain in the glass bangle industry

A preliminary survey of the few units of the small-scale glass bangle industry in Firozabad, Agra District, Uttar Pradesh, indicated that the workers were exposed to severe degrees of heat stress during various operations in the manufacturing processes. A more detailed study in eight glass bangle units was therefore undertaken to make quantitative estimates of heat stress on exposed workers in the summer season. The thermal data collected confirmed that the heat stress on the workers was severe but measurement of certain physiological indicators revealed relatively low levels of strain amongst the exposed workers. The findings could be attributable to high degrees of acclimatization, but further observations in the field supplemented by studies on simulated exposures of volunteers in a climatic chamber seem to be warranted.     

Conservation of human fibrinogen conformation after cleavage of the B beta chain NH2 terminus

Human fibrinogen exposed to protease III from Crotalus atrox venom is cleaved near the NH2 terminus of the B beta chain yielding a species of Mr 325,000 (Fg325) with impaired thrombin clottability. The derivative was compared with intact fibrinogen in a number of ways to determine whether the functional defect resulted from a conformational change or from the loss of a polymerization site. NH2-terminal amino acid sequencing of isolated A alpha, B beta, and gamma chains showed that Fg325 contained intact A alpha and gamma chains, but differed from fibrinogen by the absence of the first 42 residues of the B beta chain. Fibrinopeptide A was present and was cleaved at the same rate in both fibrinogen and Fg325. The rate and extent of A alpha and gamma cross-linking by factor XIIIa was also indistinguishable. In contrast, the thrombin-catalyzed coagulation of Fg325 was 46% less in extent and 180-fold slower than observed for intact fibrinogen. A conformational comparison of Fg325 and fibrinogen was made using immunochemical and spectroscopic approaches. Antisera specific for different regions of the fibrinogen molecule were used to characterize the epitopes in Fg325. The only significant differences were found in the NH2-terminal region of the B beta chain, probed with antiserum to B beta 1-118. The conformational similarity of Fg325 and fibrinogen was confirmed by the identity of both near and far UV CD spectra of the two proteins. Structural, functional, and immunochemical results imply that cleavage of 42 NH2-terminal residues from the B beta chain is not accompanied by a measurable conformational change. The residues of this B beta chain segment, which are evidently located on the surface of the molecule, in conjunction with the NH2-terminal part of the A alpha chain appear to play an important role in the expression of a fibrin polymerization site.     

DNA haplotype analyses of patients with hyperphenylalaninemia.

Linkage analysis of phenylketonurics has shown a strong association between the DNA haplotype at the phenylalanine hydroxylase (PAH) locus and phenylketonuria (PKU). Similarly, a genetic linkage between less severe forms of hyperphenylalaninemia (HPA) and the PAH locus has been suggested. In the present study we analyzed this linkage in more detail. Haplotypes at the PAH locus were determined for 19 individuals with moderately elevated plasma phenylalanine and normal urinary neopterin/biopterin ratios. Fourteen of these individuals had plasma phenylalanine levels of 4-10 mg/dl (mild HPA), and the other five had plasma phenylalanine levels of 10-19 mg/dl (atypical PKU). Thirteen of the 15 HPA families consisted of an affected child and at least one other sibling. Elevated plasma phenylalanine was seen to genetically segregate with specific PAH alleles in each family. Summation of the LOD scores for both categories of moderate plasma phenylalanine elevation gave a maximum value of 3.556 at theta = 0. At theta = 0 this gives a probability of linkage between the PAH locus and the locus for moderate phenylalanine elevations that is approximately 3,600:1. None of the alleles segregating with either mild HPA or atypical PKU were of haplotype 2 or 3, and 13/20 were of types 1 or 4. This is in agreement with the most deleterious mutations being on haplotypes 2 and 3 and with the less severe mutations being on haplotypes 1 and 4. chi 2 Analyses indicated no statistically significant correlation between HPA and a particular haplotype or restriction-enzyme site.     

Regional Activation of Myosin II in Cancer Cells Drives Tumor Progression via a Secretory Cross-Talk with the Immune Microenvironment

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Seed Priming with Iron Oxide Nanoparticles Triggers Iron Acquisition and Biofortification in Wheat (Triticum aestivum L.) Grains

Iron deficiency anaemia is a major challenge among consumers in developing countries. Given the deficiency of iron in the diet, there is an urgent need to devise a strategy for providing the required iron in the daily diet to counter the iron deficiency anaemia. We propose that iron biofortification of wheat (Triticum aestivum L.) through seed priming would be an innovative strategy to address this issue. This investigation attempts to find the interaction of iron oxide nanoparticles on germination, growth parameters and accumulation of grain iron in two contrasting wheat genotypes WL711 (low-iron genotype) and IITR26 (high-iron genotype). Wheat seeds were primed with different concentrations of iron oxide nanoparticles in the range of 25–600 ppm, resulting in differential accumulation of grain iron contents. We observed a pronounced increase in germination percentage and shoot length at 400 and 200 ppm treatment concentrations in IITR26 and WL711 genotypes, respectively. Intriguingly, the treatment concentration of 25 ppm demonstrated higher accumulation with a significant increase in grain iron contents to 45.7% in IITR26 and 26.8% in WL711 genotypes, respectively. Seed priming represents an innovative and user-friendly approach for wheat biofortification which triggers iron acquisition and accumulation in grains.

     

Role of glutathione S-transferases in protection against lipid peroxidation. Overexpression of hGSTA2-2 in K562 cells protects against hydrogen peroxide-induced apoptosis and inhibits JNK and caspase 3 activation

The physiological significance of the selenium-independent glutathione peroxidase (GPx) activity of glutathione S-transferases (GSTs), associated with the major Alpha class isoenzymes hGSTA1-1 and hGSTA2-2, is not known. In the present studies we demonstrate that these isoenzymes show high GPx activity toward phospholipid hydroperoxides (PL-OOH) and they can catalyze GSH-dependent reduction of PL-OOH in situ in biological membranes. A major portion of GPx activity of human liver and testis toward phosphatidylcholine hydroperoxide (PC-OOH) is contributed by the Alpha class GSTs. Overexpression of hGSTA2-2 in K562 cells attenuates lipid peroxidation under normal conditions as well as during the oxidative stress and confers about 1.5-fold resistance to these cells from H(2)O(2) cytotoxicity. Treatment with 30 microm H(2)O(2) for 48 h or 40 microm PC-OOH for 8 h causes apoptosis in control cells, whereas hGSTA2-2-overexpressing cells are protected from apoptosis under these conditions. In control cells, H(2)O(2) treatment causes an early (within 2 h), robust, and persistent (at least 24 h) activation of JNK, whereas in hGSTA2-2-overexpressing cells, only a slight activation of JNK activity is observed at 6 h which declines to basal levels within 24 h. Caspase 3-mediated poly(ADP-ribose) polymerase cleavage is also inhibited in cells overexpressing hGSTA2-2. hGSTA2 transfection does not affect the function of antioxidant enzymes including GPx activity toward H(2)O(2) suggesting that the Alpha class GSTs play an important role in regulation of the intracellular concentrations of the lipid peroxidation products that may be involved in the signaling mechanisms of apoptosis.     

Dynamics of chromosome compaction during mitosis

We have quantitatively studied the space-time dynamics of mitotic chromosome compaction in cultured amphibian cells. After collecting digital phase-contrast images we have done digital image analysis to study spatial correlations in density. We find a characteristic distance at which the strongest correlations occur, which provides a quantitative measure of the size of patches of dense chromatin during interphase and early prophase. Later in mitosis, this length corresponds to the thickness of prophase and metaphase chromosomes. We find that during interphase strong correlations exist at a few-micrometer length; during prophase this correlation length progressively drops as the chromosomes are compacted. Our data are explained by a model based on assembly of chromatin loops onto already fiberlike interphase chromosomes. To test this model we have microinjected cobalt hexamine trichloride into interphase nuclei and have observed the rapid condensation of the interphase chromatin into thick fibers with a spacing similar to the native-state interphase correlation length determined from our image analysis.