Browsing by Author "Singh, Rajendra"
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Item Characterization of differentially expressed stress-associated proteins in starch granule development under heat stress in wheat (Triticum aestivum L.).(2013-04) Kumar, Ranjeet R; Sharma, Sushil K; Goswami, Suneha; Singh, G P; Singh, Rajendra; Singh, Khushboo; Pathak, Himanshu; Rai, Raj DAbiotic stress causes abrupt increase in the expression of stress-associated proteins, which provide tolerance by modulating the defense mechanism of plants. Small heat shock proteins (sHSPs) and anti-oxidant enzymes are important for environmental stress tolerance of the plants. In this study, two full-length cDNAs encoding small heat shock protein (sHSP) and superoxide dismutase (SOD), designated as TasHSP and SODI were identified and characterized from C-306 (thermotolerant) and PBW343 (thermosusceptible) cultivars of wheat (Triticum aestivum L.). An alpha crystalline domain was observed in TasHSP and manganese/iron binding domain in case of SODI. Quantitative real-time PCR showed very high transcript level of TasHSP and SOD in C-306 compared to PBW343 at different stages of growth and against differential heat stress (HS). Under differential HS at milky-dough stage, the fold change in transcript of both TasHSP and SOD was observed maximum in C-306, compared to PBW343. Protein profiling and isoenzymes analysis showed the expression of several heat-stable proteins and prominent isoenzymes of SOD in C-306, compared to PBW343. Scanning electron microscopy (SEM) of starch granules showed globular, well-shaped and more numbers of endospermic cells in C-306, compared to defragmented, irregular shaped and shrunken granules in case of PBW343 under HS treatment (42°C for 2 h). Diurnal change in soluble starch synthase (SSS) activity showed an increase in the activity during afternoon (35°C), compared to morning (29°C) and evening (32°C) in both the cultivars. Under heat stress (42°C for 2 h), a drastic decrease in the SSS activity was observed, due to the thermal denaturation of the enzyme. Thermotolerance capacity analyzed using cell membrane stability (CMS) showed significantly higher CMS in case of C-306, compared to PBW343 at different stages of growth. Findings suggest that abundance of TasHSP and SODI during milky-dough stage plays a very important role in starch granule biosynthesis. The mechanism may be further exploited to develop tolerant wheat cultivar with high quality seeds.Item Influence of light intensity, temperature and CO2 concentration on growth and lipids in green algae and cyanobacteria.(2016-07) Shukla, Madhulika; Tabassum, Rizwana; Singh, Rajendra; Dhar, Dolly WattalEffects of the environmental variables such as light intensity (µmol photons m-2s-1), temperature (°C) and CO2 concentration (ppm) on chlorophyll, total soluble proteins and lipids were studied in selected microalgal strains from Chlorophyceae (Chlamydomonas sp., Scenedesmus sp., Chlorella sp., Kirchneriella sp.) and cyanobacteria (Nostoc sp.1, Anabaena sp., Nostoc sp. 2, Cylindrospermum sp.). Cultures were grown under controlled conditions at the National Phytotron Facility, Indian Agricultural Research Institute (IARI), New Delhi. Our results showed that chlorophyll concentration enhanced with increased CO2. Chlorella exhibited the highest chlorophyll at 850 ppm CO2 and 28°C; for Chlamydomonas it was at 78 µmol photons m-2s-1 light intensity. In Cylindrospermum, total soluble proteins decreased with enhanced CO2, and were highest at 18°C. In Anabaena, a light intensity of 65 µmol photons m-2s-1 was best for maximum total soluble proteins. In Chlorella, CO2 @ 850 ppm was most suited for maximum lipid accumulation. In Kirchneriella, increase in temperature, from 18°C up to 37°C, increased total lipids; the highest was at 28°C. In Chlamydomonas, the light intensity of 78 µmol photons m-2s-1 was optimum for lipid accumulation and the maximum total lipids was 30.8 (% dry wt.).Item Unusual cause of hypoxemia after automatic implantable cardioverter‑defibrillatorleads extraction.(2015-10) Raju, Dinesh; Roysam, Chandrika; Singh, Rajendra; Clark, Stephen C; Plummer, ChristopherThe indication of pacemaker/AICD removal are numerous. Serious complication can occur during their removal, severe tricuspid regurgitation is one of the complication. The occurrence of PFO is not uncommon among adult population. Shunting across PFO in most circumstance is negligible, but in some necessitates closure due to hypoxemia. We report a case of 62 year old man, while undergoing AICD removal, had an emergency sternotomy for cardiac tamponade. Postoperatively, he experienced profound hypoxemia refractory to oxygen therapy. Transthoracic Echocardiogram was performed to rule out intracardiac shunts at an early stage, but it was difficult to obtain an good imaging windows poststernotomy. A small pulmonary emboli was noted on CTPA, but was not sufficient to account for the level of hypoxemia and did not resolve with anticoagulation. Transesophageal echocardiogram showed flail septal tricuspid valve with severe TR and bidirectional shunt through large PFO. Patient was posted for surgery, tricuspid valve was replaced and PFO surgically closed. Subsequently, patient recovered well ad was discharged to home. Cause of hypoxemia might be due to respiratory or cardiac dysfunction. But for hypoxemia refractory to oxygen therapy, transoesophageal echocardiogram should be always considered and performed early as an diagnostic tool in post cardiac surgical patients.