Analysis of BAC-end sequences (BESs) and development of BES-SSR markers for genetic mapping and hybrid purity assessment in pigeonpea (Cajanus spp.).

BACKGROUND: Pigeonpea [Cajanus cajan (L.) Millsp.] is an important legume crop of rainfed agriculture. Despite of concerted research efforts directed to pigeonpea improvement, stagnated productivity of pigeonpea during last several decades may be accounted to prevalence of various biotic and abiotic constraints and the situation is exacerbated by availability of inadequate genomic resources to undertake any molecular breeding programme for accelerated crop improvement. With the objective of enhancing genomic resources for pigeonpea, this study reports for the first time, large scale development of SSR markers from BAC-end sequences and their subsequent use for genetic mapping and hybridity testing in pigeonpea. RESULTS: A set of 88,860 BAC (bacterial artificial chromosome)-end sequences (BESs) were generated after constructing two BAC libraries by using HindIII (34,560 clones) and BamHI (34,560 clones) restriction enzymes. Clustering based on sequence identity of BESs yielded a set of >52K non-redundant sequences, comprising 35 Mbp or >4% of the pigeonpea genome. These sequences were analyzed to develop annotation lists and subdivide the BESs into genome fractions (e.g., genes, retroelements, transpons and non-annotated sequences). Parallel analysis of BESs for microsatellites or simple sequence repeats (SSRs) identified 18,149 SSRs, from which a set of 6,212 SSRs were selected for further analysis. A total of 3,072 novel SSR primer pairs were synthesized and tested for length polymorphism on a set of 22 parental genotypes of 13 mapping populations segregating for traits of interest. In total, we identified 842 polymorphic SSR markers that will have utility in pigeonpea improvement. Based on these markers, the first SSR-based genetic map comprising of 239 loci was developed for this previously uncharacterized genome. Utility of developed SSR markers was also demonstrated by identifying a set of 42 markers each for two hybrids (ICPH 2671 and ICPH 2438) for genetic purity assessment in commercial hybrid breeding programme. CONCLUSION: In summary, while BAC libraries and BESs should be useful for genomics studies, BES-SSR markers, and the genetic map should be very useful for linking the genetic map with a future physical map as well as for molecular breeding in pigeonpea.

Study of the effect of stress on skeletal muscle function in geriatrics.

BACKGROUND: Old age is associated with weakness of skeletal muscles and decrease in muscle functions. Usually in old-age, people undergo wasting of muscles, so they are more prone for fall and fracture. It has been stated that stress and cognition has an impact on muscle functions. This study was intended to demonstrate the effect of stress in muscle function in geriatrics. METHODS: This was a cross sectional study done at a charitable home in Chennai sub urban. The geriatric males and females in the old age home were included in this study. Sixty-four subjects were included and the persons with previous history of musculo skeletal and neurological disorders were excluded. Anthropometric parameters were recorded Maximum Voluntary Contraction (MVC) and Endurance Time (ET) were measured by hand grip dynamometer. Perceived stress score was measured by perceived stress scale questionnaire. Muscle function parameters and stress score was compared. RESULTS: Sixty-four subjects were included in this study and it was found out that there is a negative correlation between MVC & stress which was statistically significant. (r = -0.0675, P = 0.000). Age with MVC & ET showed a mild negative correlation but it was not significant. CONCLUSION: Hormones released during stress have a negative metabolic effect in skeletal muscle. Stress can induce earlier decline in muscle strength which will eventually lead to fall and fracture. Therefore, stress should be viewed as an independent risk factor for disability and other co morbid conditions.

Role of biological sex in normal cardiac function and in its disease outcome - a review.

Biological sex plays an important role in normal cardiac physiology as well as in the heart's response to cardiac disease. Women generally have better cardiac function and survival than do men in the face of cardiac disease; however, this is progressively lost when comparing postmenopausal women with age matched men. Animal model of cardiac disease mirror what is seen in humans. Sex hormones contribute significantly to sex based difference in cardiac functioning and in its disease outcome. Estrogen is considered to be cardioprotective, whereas testosterone is detrimental to heart function.

Dyslipidaemic changes in women with subclinical hypothyroidism.

BACKGROUND: In overt hypothyroidism, many lipid abnormalities have been documented. This study was intended to demonstrate the levels of lipid in women with subclinical hypothyroidism (SH). MATERIAL AND METHODS: This was a case control study which was done at referral Centre in Chennai. Women with subclinical hypothyroidism and euthyroid women attending our master health checkup clinic were enrolled in this study.Their lipid profile, fasting blood sugar, T3,T4 and TSH levels were measured. In subclinical hypothyroidism, various parameters were compared. RESULTS: Thirty euthyroid and 30 age matched subclinical hypothyroid women were enrolled in this study. There were significant dyslipidaemic changes is SH women as compared to euthyroid controls. Serum total cholesterol and triglyceride levels were significantly higher as compared to those in controls. LDL levels were higher is SH women, but did not reach statistical significance and lower levels of HDL were noticed in SH subjects as compared to those in euthyroid women. A positive association was also reported between serum TSH and lipid parameters in our study group. CONCLUSION: SH, the earliest form of thyroid failure, has negative metabolic effects on the affected subjects.SH could be one of the causes of secondary hyperlipidaemia and should be viewed as an independent risk factor for atherosclerosis, along with obesity, hypertension, diabetes, etc.