Masroor A. Baig

Simultaneous Selection of the Wild-type Genotypes of the G894T and 4B/ 4A Polymorphisms ofNOS3Associate with High-altitude Adaptation: NOS3Genotypes Associate with HA Adaptation

The routine performance of high‐altitude (HA) natives in the hypoxic environment of HA exemplifies the process of adaptation mainly through natural selection. The recent therapeutic application of nitric oxide (NO) in HA disorders, for the improvement of oxygenation and vasodilation, ushered us to investigate the endothelial nitric oxide synthase gene (NOS3) with respect to HA adaptation. The study subjects, 131 HA monks (HAM), 136 HA controls (HAC), and 170 lowlanders (LLs) were screened for NOS3 G894T (Glu298Asp) and 4B/4A polymorphisms. The NO levels were estimated, for a correlation with the polymorphisms. The three groups were in Hardy‐Weinberg equilibrium for the polymorphisms. The overall genotype distributions for the G894T and 4B/4A polymorphisms were significant (P = 0.01 and 0.02, respectively) in the three groups. Wild‐type alleles G and 4B were significantly over‐represented in the HA groups as compared to the LLs (P = 0.006 and P = 0.02, respectively). The NO levels were in the order of HAM>HAC>LLs (P < 0.0001). Furthermore, combinations of the GG and BB genotypes were distributed significantly more frequently in the HAM (P < 0.0001) and HAC (P = 0.0005) than in LLs. The NO levels contributed by the wild‐type genotype combination GG, BB were significantly elevated when compared with the remaining eight genotype combinations together in the HAM, HAC and LLs (P = 0.003, P = 0.0006 and P < 0.0001, respectively). To conclude, the genotype combination of NOS3 wild‐type homozygotes (GG, BB) was found significantly more frequently in HA groups than in LLs, by contributing to higher NO levels associated with HA adaptation.

Characterisation of senescence-induced changes in light harvesting complex II and photosystem I complex of thylakoids ofCucumis sativus cotyledons: Age induced association of LHCII with photosystem I

Structure and function of chloroplasts are known to after during senescence. The senescence-induced specific changes in light harvesting antenna of photosystem II (PSII) and photosystem I (PSI) were investigated in Cucumis cotyledons. Purified light harvesting complex II (LHCII) and photosystem I complex were isolated from 6-day non-senescing and 27-day senescing Cucumis cotyledons. The chlorophyll a/b ratio of LHCII obtained from 6-day-old control cotyledons and their absorption, chlorophyll a fluorescence emission and the circular dichroism (CD) spectral properties were comparable to the LHCII preparations from other plants such as pea and spinach. The purified LHCII obtained from 27-day senescing cotyledons had a Chl a/b ratio of 1.25 instead of 1.2 as with 6-day LHCII and also exhibited significant changes in the visible CD spectrum compared to that of 6-day LHCII, indicating some specific alterations in the organisation of chlorophylls of LHCII. The light harvesting antenna of photosystems are likely to be altered due to aging. The room temperature absorption spectrum of LHCII obtained from 27-day senescing cotyledons showed changes in the peak positions. Similarly, comparison of 77K chlorophyll a fluorescence emission characteristics of LHCII preparation from senescing cotyledons with that of control showed a small shift in the peak position and the alteration in the emission profile, which is suggestive of possible changes in energy transfer within LHCII chlorophylls. Further, the salt induced aggregation of LHCII samples was lower, resulting in lower yields of LHCII from 27-day cotyledons than from normal cotyledons. Moreover, the PSI preparations of 6-day cotyledons showed Chl a/b ratios of 5 to 5.5, where as the PSI sample of 27-day cotyledons had a Chl a/b ratio of 2.9 suggesting LHCII association with PSI. The absorption, fluorescence emission and visible CD spectral measurements as well as the polypeptide profiles of 27-day cotyledon-PSI complexes indicated age-induced association of LHCII of PSII with PSI obtained from 27-day cotyledons. We modified our isolation protocols by increasing the duration of detergent Triton X-100 treatment for preparing the PSI and LHCII complexes from 27-day cotyledons. However, the PSI complexes isolated from senescing samples invariably proved to have significantly low Chl a/b ratio suggesting an age induced lateral movement and possible association of LHCII with PSI complexes. The analyses of polypeptide compositions of LHCII and PSI holocomplexes isolated from 6-day control and 27-day senescing cotyledons showed distinctive differences in their profiles. The presence of 26-28 kDa polypeptide in PSI complexes from 27-day cotyledons, but not in 6-day control PSI complexes is in agreement with the notion that senescence induced migration of LHCII to stroma lamellae and its possible association with PSI. We suggest that the migration of LHCII to the stroma lamellae region and its possible association with PSI might cause the destacking and flattening of grana structure during senescence of the chloroplasts. Such structural changes in light harvesting antenna are likely to alter energy transfer between two photosystems. The nature of aging induced migration and association of LHCII with PSI and its existence in other senescing systems need to be estimated in the future.

Methanol-induced neurotoxicity in pups exposed during lactation through mother Role of folic acid

Role of folic acid on methanol-induced neurotoxicity was studied in pups at Postnatal Day (PND) 45 exposed to methanol (1%, 2% and 4%, v/v) during lactation through mothers maintained on folic acid-deficient (FD) and folic acid-sufficient (FS) diet. A gradual loss in the body weight gain was observed in the pups exposed to 2% and 4% methanol in the FD group, while FS group exhibited this alteration only at 4% exposure. The assessment of spontaneous locomotor activity (SLA) showing a significant increase in the distance travelled was observed in the 2% and 4% methanol-exposed groups in both the FS and FD animals when compared with their respective controls, but the effect was more marked in the FD group. A significant decrease in the conditioned avoidance response (CAR) was observed in pups exposed to 2% and 4% methanol in the FD group at PND 45. The results also suggest that disturbances in dopaminergic and cholinergic receptors were more pronounced in the FD group as compared to the FS group. A significant decrease in striatal dopamine levels was also observed in the FD group at 2% and 4% methanol exposure, while in the FS group, a significant decrease was exhibited only at 4% methanol exposure. An aberrant increase in the expression of Growth-Associated Protein (GAP-43), a neuron-specific growth-associated protein was observed in pups in the FD group exposed to 2% and 4% methanol, while an increase in the expression of GAP-43 in the FS group was found only at 4% methanol exposure in the hippocampal region as compared to their respective controls. Results suggests that methanol exposure during growth spurt period adversely affects the developing brain, the effect being more pronounced in FD rats as compared to FS rats, suggesting a possible role of folic acid in methanol-induced neurotoxicity.

Differential Changes in the Steady State Levels of Thylakoid Membrane Proteins during Senescence in Cucumis sativus Cotyledons

Chloroplast structure and function is known to alter during foliar senescence. Besides, the alterations in the structural organisation of thylakoid membranes changes in the steady state levels of thylakoid membrane proteins occur due to leaf ageing. We monitored temporal changes in some of the specific proteins of thylakoid membrane protein complexes by western blotting in the Cucumis sativus cotyledons as a function of the cotyledon age. We observed that the levels of D1 and D2 proteins of photosystem II started declining at the early stages of senescence of Cucumis cotyledons and continued to decline with the progress of cotyledon age. Similarly the level of Cyt f of Cyt b6/f complex declined rapidly with progress of senescence in these cotyledons. The reaction centre proteins of photosystem I were relatively found to be more stable than that of photosystem II reaction centre proteins reflecting possibly the disorganisation of photosystem II prior to photosystem I. The 33 kDa extrinsic protein (MSP) of oxygen evolving complex, the LHCII apoprotein and the β-subunit of ATPsynthase showed the declined levels with the progress of cotyledon age. However, the extents of loss of these proteins were not as high as the reaction centre proteins of photosystem II and the Cyt f. These results provide that during senescence, proteins of thylakoid membranes degrade in a specific temporal sequence and thereby affect the temporal photochemical functions in Cucumis sativus cotyledons

Alteration in Cellular and Biochemical Markers of Pulmonary Toxicity in Rat Lung Exposed to Carpet Dusts

Epidemiological studies of workers in weaving units in carpet industries have shown relationships between the airborne dust concentrations and pulmonary ill health. Therefore, to predict the health risk of carpet weavers, this preliminary experiment was conducted to evaluate the effect of carpet dust (knotted, tufted) on cellular and biochemical mediators considered as potential biological markers of lung injury. Lung cytoplasmic (lactate dehydrogenase, LDH), lysosomal (acid phosphatase, ACP), type II (alkaline phoshatase, ALP) and Clara-cell marker enzymes (gamma-glutamyl transferase, GGT) were monitored in rat cell-free lung lavage (BAL) during postexposure days 1, 4, 8, and 16. Furthermore, lung microsomal cytochrome P-450 (CYP450) and Clara-cell secretory protein (CC16) content in BAL was also evaluated. These pulmonary marker enzymes were significantly elevated during the postexposure period over the respective untreated control; however, tufted carpet dust shows more responses than knotted carpet dust. Lung CYP450 content was reduced significantly at early days; the pattern shows the reoccurrence of CYP450 content in the later stage of postexposure to carpet dust. Clara-cell secretory protein in BAL shows decline in the carpet-treated group; however, tufted carpet shows more decline than knotted carpet. Thus, reduction in CC16 level may have important implication in the development of chronic lung inflammation and diseases. Present investigation found that modulation of these cellular marker enzymes is clear evidence of pulmonary damage caused by exposure to carpet dust.

Alterations in Electron Transport Characteristics during Senescence of Cucumis Cotyledonary Leaves. Analysis of the Effects of Inhibitors

Cotyledonary leaves of Cucumis sativus cv. Poinsette exhibited senescence-induced losses in chlorophyll (Chl) and protein contents within three weeks since germination. Chl and protein concentrations in cotyledonary leaves approached maximum on 6th d after germination and they declined to 50 and 41 %, respectively, by the 20th day of growth. Activities of both photosystem (PS) 2 and PS1 decreased by 33 and 31 %, respectively, on the 20th day, compared to the control 6th day. Changes in sensitivity of PS2 to inhibitors like atrazine and dibromothymoquinone and sensitivity of PS1 to KCN accompanied the changes in PS2 and PS1 activities. Hence both the acceptor side of PS2 and the donor side of PS1 are affected by senescence-induced changes in cucumber cotyledonary leaves.

Differential responses of rat alveolar macrophages to carpet dust in vitro

Epidemiological studies of workers in carpet weaving units in carpet industries have shown a direct relation between the concentration of carpet dust in the air and respiratory symptoms. To predict the health risk of carpet weavers, this preliminary study was conducted to evaluate the toxic potential of different types of workplace dust by using alveolar macrophages (AMs). Several parameters were observed for cytotoxicity such as cell viability, the release of lactate dehydrogenase (LDH) in rat AMs treated with different concentration of carpet dust and haemolytic potential of erythrocytes. In addition, reactive oxygen/nitrogen species-inducing effects of carpet dust were assessed by nitric oxide (NO), reduced glutathione (GSH) release and hydrogen peroxide (H2O2) generation in AMs. Results of cell viability and hemolytic assay showed a direct correlation between increasing the dust concentration with enhancing the toxic effect. Knotted and tufted carpet dust increases the release of LDH, NO, GSH and H2O2 production with increasing dust concentration. Present observations have revealed that dusts collected from tufted carpet weaving units exhibited more toxicity to AMs than knotted carpet dust. These data further suggest that injurious effects of carpet dust to AMs could pave a way to evaluate the toxic potential of the different types of workplace dusts and component(s) involved in it.