Cross-species amplification of microsatellite markers in Mycteria leucocephala Pennant 1769: Molted feathers as successful DNA source.

DNA from molted feathers is being increasingly used for genetic studies on birds. However, the DNA obtained from such non-invasive sources is often not of enough quantity and quality for isolation of new microsatellite markers. The present study examined the potential of shed feathers of near threatened Painted Stork as a source of its DNA for cross-species amplification of microsatellites. Thirty-one shed feathers of varying conditions (‘good’ and ‘deteriorated’) and sizes (‘large’, ‘intermediate’ and ‘small’) collected in a north Indian population were used to isolate DNA by a standard isopropanol method and 11 microsatellite markers already developed in the Wood Stork were screened for amplification. Nine plucked feathers from two dead Painted Storks were also used to compare the DNA yield and amplification success. The DNA yield of feathers varied significantly in relation to the calamus size and condition. Among molted feathers, ‘good’ and ‘large’ samples provided more DNA than ‘deteriorated’ and ‘small’ ones, respectively. ‘Large’ plucked feathers yielded more DNA than ‘large’ molted feathers. DNA was almost degraded in all the samples and ratio of absorbance at 260/280 nm varied from 1.0 to 1.8, indicating impurity in many samples. Independent of DNA yields, all microsatellites were cross-amplified in all kinds of feathers, with >80% success in different feather categories. It is concluded that the shed feathers can be successfully used to isolate DNA in the Painted Stork and for cross-species amplification of microsatellites.

Effect of low level microwave radiation exposure on cognitive function and oxidative stress in rats.

Use of wireless communicating devices is increasing at an exponential rate in present time and is raising serious concerns about possible adverse effects of microwave (MW) radiation emitted from these devices on human health. The present study aimed to evaluate the effects of 900 MHz MW radiation exposure on cognitive function and oxidative stress in blood of Fischer rats. Animals were divided into two groups (6 animals/group): Group I (MW-exposed) and Group II (Sham-exposed). Animals were subjected to MW exposure (Frequency 900 MHz; specific absorption rate 8.4738 × 10-5 W/kg) in Gigahertz transverse electromagnetic cell (GTEM) for 30 days (2 h/day, 5 days/week). Subsequently, cognitive function and oxidative stress parameters were examined for each group. Results showed significant impairment in cognitive function and increase in oxidative stress, as evidenced by the increase in levels of MDA (a marker of lipid peroxidation) and protein carbonyl (a marker of protein oxidation) and unaltered GSH content in blood. Thus, the study demonstrated that low level MW radiation had significant effect on cognitive function and was also capable of leading to oxidative stress.

Microwave radiation induced oxidative stress, cognitive impairment and inflammation in brain of Fischer rats.

Public concerns over possible adverse effects of microwave radiation emitted by mobile phones on health are increasing. To evaluate the intensity of oxidative stress, cognitive impairment and inflammation in brain of Fischer rats exposed to microwave radiation, male Fischer-344 rats were exposed to 900 MHz microwave radiation (SAR = 5.953×10-4 W/kg) and 1800 MHz microwave radiation (SAR = 5.835×10-4 W/kg) for 30 days (2 h/day). Significant impairment in cognitive function and induction of oxidative stress in brain tissues of microwave exposed rats were observed in comparison with sham exposed groups. Further, significant increase in level of cytokines (IL-6 and TNF-) was also observed following microwave exposure. Results of the present study indicated that increased oxidative stress due to microwave exposure may contribute to cognitive impairment and inflammation in brain.

Effect of GSTM1 and GSTT1 double deletions in the development of oxidative stress in diabetic nephropathy patients.

Association of diabetic nephropathy (DN) with the deletion of GSTT1 and GSTM1 genes is well reported. Oxidative stress (OS) has also been associated with the development of DN. The present study was conducted to find out, whether these deletions had any contributory role in the development of OS in patients with DN. Pre-dialysis venous blood samples were obtained from 60 patients with diabetic end-stage renal disease (stages 4 and 5). Reduced-glutathione (GSH), glutathione S-transferase (GST) activity and malondialdehyde (MDA) levels were measured for the assessment of OS. Genetic polymorphism analysis of DN patients revealed the following distribution pattern: GSTM1 null 46.7%; GSTT1 null 55%; both null 30% and both positive 28.3%. Patients with both null genotypes were found to have significantly increased levels of MDA and low GST activity as compared to other genotypic groups. Lower GSH levels were observed in all the genotypic groups as compared to both positives. Double deletions involving GSTT1 and GSTM1 may result in decreased GST levels, leading to increased OS as reflected by increased MDA levels. As GST is a multi-functional enzyme involved in xenobiotic metabolism, this double null genotype population has a greater risk of development of DN. Further studies using increased sample size to find out the allelic distribution and their role in the development of DN are in progress.

Impact of oral vitamin E supplementation on oxidative stress & lipid peroxidation in patients with polymorphous light eruption.

BACKGROUND & OBJECTIVES: Polymorphous light eruption (PMLE) is a photo-induced disease which clinically manifests in the form of pruritic eruptions on sun/light exposed parts. Little is known about lipid peroxidation and free radical scavengers in patients during PMLE. The present study was therefore undertaken to evaluate oxidative stress and levels of antioxidant enzymes in patients of PMLE. METHODS: The PMLE was diagnosed clinically by a consultant dermatologist and validated independently by another and through histopathologic findings. Blood samples were collected on day 1 and patients were given oral vitamin E supplementation (400 mg OD) along with topical sunscreen and advice for photo-protection. Samples were collected again after one week. The blood samples were evaluated for lipid peroxidation, oxygen free radical (OFR) scavenging enzymes, glutathione (GSH) and related enzymes such as glutathione reductase (GR), glutathione peroxidase (GPx), gamma glutamyl transpeptidase (GGT) and glutathione- S-transferase (GST) in erythrocytes and compared with healthy controls. RESULTS: The serum malondialdehyde (MDA) level was higher and GSH level was lower in PMLE cases as compared to controls. There was a significant decrease in superoxide dismutase (SOD) activity while activities of catalase (CAT) and glutathione related enzymes were increased in PMLE cases. Administration of oral vitamin E for one week, along with photoprotection resulted in a significant decrease in MDA levels and activities of all others enzymes except SOD. The GSH was replenished and returned to normal. INTERPRETATION & CONCLUSION: Oxidative stress and differential modulation of antioxidant enzymes in PMLE might play a pathogenic role in humans, which supports the incorporation of antioxidant drugs in the treatment protocol of the disease.