Genetic diversity and marker trait association for yellow mosaic virus disease in green gram, Vigna radiata (L.) Wilczek

Yellow mosaic virus (YMV) disease is known to cause severe damage in green gram in terms of yield loss. As the resistance is often governed by recessive genes, introgression of such resistance faces some difficulty. DNA molecular markers are reported to be effective in this process. However, validation of such markers is important. Here, we have made an attempt to validate DNA markers associated with YMV disease resistance gene from a diverse group of 26 green gram genotypes. A total of 19 molecular markers were used to assess the susceptibility or resistance against YMV disease. Results show that among the amplified 31 alleles, 21 were polymorphic, with a mean of 1.1.0 per locus. The polymorphism information content (PIC) values ranged from 0.32 to 0.80. Only five markers exhibited higher PIC value (>6.0) and were revealed to be polymorphic, suggesting its utility in marker assisted selection for breeding YMV resistant genotypes in greengram. Dice dissimilarity coefficient among the genotypes exhibited a range of 0.07 to 1.0 which show a wide genetic variation among the genotypes for YMV tolerance. Neighbor-joining cluster analysis has grouped 26 green gram genotypes into 4 main clusters which revealed the existence of genetic dissimilarities among the genotypes. The genotypes AUGG 6, VBN (Gg) 2 and CO (Gg) 8 carried the positive alleles for YMV disease resistance and the allele for susceptibility were found in the genotypes AUGG 12, AUGG 15, AUGG 17 and AUGG 19. Single marker analysis indicated that there was correlation between the markers and the disease reaction in the field with exceptions. The findings revealed that the SSR markers CEDG180 and YR4 could be used to screen germplasm in order to discriminate the YMV resistant genotypes from the susceptible genotypes in marker assisted selection.

Carrier detection in Duchenne muscular dystrophy using molecular methods.

Background & objectives: Duchenne and Becker muscular dystrophies are X-linked allelic disorders which are caused by mutations in the DMD gene. Carrier analysis in DMD is complicated due to the heterozygous nature of the X chromosome. Several techniques have been tried for carrier analysis in families where the mutation is identified including quantitative multiplex PCR (qmPCR), Southern blot, and now multiplex ligation-dependent probe amplification (MLPA). Linkage analysis is used in cases without identifiable mutations. The present study was undertaken to determine the status of probable carriers in families where the DMD deletion/duplication has been identified for the affected index cases. Methods: Carrier status was present in 150 probable carriers from 110 apparently unrelated families where the patients’ mutations were known. Of these 110 families, 100 were deletions, 9 duplications and 1 point mutation. Multiplex ligation-dependent probe amplification (MLPA) was used to assess the copy number changes and direct sequencing was used for the case with the point mutation. Results: Of the 150 cases, 49 were found to be carriers. Among the sporadic cases, it was observed that the rate of de novo mutations was very high (71%) as compared to the hereditary cases (29%), which was higher than the calculated rate (30%). It was observed that this difference was more apparent in deletion mutations than in duplications. Interpretation & conclusions: Identifying the DMD carrier rates in the families with unidentified deletions and duplications and where the causative mutation could be small insertions/deletions or point mutations could throw more light into this observation. MLPA was found to be useful in detecting copy number changes in DMD carriers and this could be the method of choice for DMD carrier analysis, when the mutation is detected in the affected child.

Use of multiplex ligation-dependent probe amplification (MLPA) for Duchenne muscular dystrophy (DMD) gene mutation analysis.

Background & objectives: Duchenne (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive disorders, caused by mutations in the dystrophin gene. Genetic diagnosis of the proband becomes crucial, and forms the base for carrier analysis, genetic counselling, prediction of natural history and prognosis, and eligibility for therapeutic strategies. Traditional multiplex PCR assay is the common method used in India to detect DMD gene deletions, mainly in the hot-spot region. Deletions of exons outside the usual 18 or 21 exons in the hot-spot, duplications and carrier analysis are often left without precise genetic diagnosis and require efficient dosage/quantitative analysis. In this study we evaluated the efficacy of using multiplex PCR (mPCR) of 30 exons followed by multiplex ligation-dependent probe amplification (MLPA), to study deletions and duplications in the DMD gene in patients clinically diagnosed as BMD/DMD. Methods: Using an algorithm of mPCR and MLPA which was less invasive and cost-effective, we performed retrospective and prospective analysis on 150 male patients. Results: Multiplex PCR could pick up deletions in 103 of the 150 cases. MLPA was able to detect deletions and duplications including nine additional mutations. Further, the borders of the deletions and duplications were more accurately defined by this recent methodology, which enables one to determine the effect of the mutation on the reading frame. In all, including the single exon deletions, MLPA was efficient in accurately confirming mutations in 35 per cent of all cases. Ten novel mutations were identified in this study. Overall, this approach confirmed mutations in 75 per cent of the patients in our study. Interpretations & conclusions: The systematic approach/algorithm used in this study offers the best possible economical mutation analysis in the Indian scenario.

Disseminated Tuberculosis with involvement of prostate - A case report.

We present a 55-year-old male who presented with painful non-healing ulcers on the lower lip and scrotum associated with productive cough, fever, anorexia and dysuria. Erythrocyte sedimentation rate was raised, sputum was positive for acid fast bacilli. Chest X-ray was suggestive of pulmonary tuberculosis. A prostate biopsy was also suggestive of tuberculosis. A diagnosis of disseminated tuberculosis was made and the patient showed a good response in two weeks.

Bacteriological analysis of water samples from tsunami hit coastal areas of Kanyakumari district, Tamil Nadu.

Water borne diseases such as cholera, enteric fever and dysentery were expected after the tsunami, which hit the coastal areas of Kanyakumari district, Tamil Nadu. In the present study 151 drinking water sources were collected from the tsunami affected villages and relief shelters and tested for coliforms and pathogens. Nine well water samples were also collected for specific bacteriological analysis. Presence of coliforms was detected in 56 (37%) water samples. One isolate each of Salmonella Paratyphi B and NAG Vibrio were isolated from two well water samples. There was no report of acute diarrhoeal diseases or typhoid illness during the post tsunami period monitored by a field microbiology laboratory for a month.

Serosurvey of rubella in five blocks of Tamil Nadu.

BACKGROUND & OBJECTIVE: Rubella, normally a mild, self-limiting disease characterized by rash, fever and lymphadenopathy, is a vaccine preventable disease. It carries little morbidity and apparently only minor complications in children. Infection during early pregnancy may lead to congenital rubella infection. Presence of rubella specific IgG in an unvaccinated population is a long term marker of previous rubella infection, which helps to assess the immune status of that population. Though many seroprevalence studies on rebella have been reported earlier from India, no study has been conducted in recent years. We undertook this study in 2003 in five blocks identified by the Integrated Child Development Scheme (ICDS), in the five districts of Tamil Nadu to assess the immune status to rubella in two age groups (1-5 yr boys and girls and 10-16 yr adolescent girls) before vaccination and draw strategies for future vaccination programme. METHODS: A total of 300 blood samples were collected by vein puncture from girls and boys of 1-5 yr age and adolescent girls of 10-16 yr age. Samples were tested for the presence of rubella specific IgG antibody by ELISA. RESULTS: Of the 300 samples tested, 145 (48.3%) were negative for rubella IgG antibodies. The seronegativity was 82.2 per cent in 1-5 yr and 13.5 per cent in the 10-16 yr age groups, the difference was statistically significant (P<0.001). INTERPRETATION & CONCLUSION: Large percentage of children, 82.2 per cent in the 1-5 yr age group and 13.5 per cent in 10-16 yr population were susceptible to rubella infection highlighting the fact that there was a risk of congenital rubella syndrome. There is a need to implement routine measles, mumps, rubella (MMR) immunization programme for under five children and mass scale one time immunization with monovalent rubella vaccine for adolescent girls.

Plasma CRP level predicts left ventricular function and exercise capacity in patients with acute myocardial infarction.

BACKGROUND: C-reactive protein estimation can help in predicting short- and long-term prognosis after acute myocardial infarction. High plasma C-reactive protein level in the acute phase strongly indicates a poor clinical outcome of the patients with myocardial infarction. METHODS AND RESULTS: One hundred consecutive patients admitted with ST elevation myocardial infarction in the intensive coronary care unit in our hospital who were able to do symptom-limited treadmill test during early recovery phase were studied. Plasma C-reactive protein was measured at the time of admission by immunoturbidity method. The normal value of the C-reactive protein was taken as 0.8 mg/dl. Echocardiographic study was done on day three of admission and ejection fraction was estimated by modified Simpson's method. Symptom-limited treadmill exercise test was done in all the patients. Patients were classified into two groups based on level of C-reactive protein: those with low C-reactive protein level (1.26 +/- 0.91 mg/dl, n=40) and those with high C-reactive protein level (6.52 +/- 3.97 mg/dl, n=60). Ejection fraction was lower in high C-reactive protein group (46.7 +/- 11.9%) compared to low C-reactive protein group (56.9 +/- 7.7%) (p = 0.011). Exercise capacity was lower in high C-reactive protein group (2.8 +/- 1.4 METs) compared to low C-reactive protein group (5.5 +/- 2.5 METs) p = 0.027). CONCLUSIONS: C-reactive protein levels are an index of the severity of myocardial necrosis which translate to worse left ventricular function. Higher the C-reactive protein level, lower the ejection fraction and worse may be the prognosis.