Why and how putrescine modulates thermotolerance in wheat?

Effects of putrescine (Put) and high temperature (HT) on the responses of wheat (Triticum aestivum L.) seedlings or developing grains were studied in six wheat cultivars (PBW 343, C 273, C 306, PBW 550, PBW 621 and HD 2967) raised in the laboratory (25°C or 32°C) in Petri dishes for seven days or in the field under normal (November) and late (December) planting conditions. High temperature significantly reduced root/shoot lengths and dry weights of all the six cultivars, whereas Put ameliorated this effect by increasing these attributes. C 306 and C 273 showed higher root/shoot lengths and dry weights over PBW 550, PBW 621. High temperature significantly increased the activities of ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and catalase in correspondence with an increase in membrane injury index (MII) and thiobarbituric acid reactive substances (TBARs) and H2O2 contents. Application of Put under HT further elevated activities of these enzymes whereas MII and contents of TBARs, H2O2 were reduced. In fact, Put treated seedlings performed better in terms of antioxidant response under HT than seedlings in absence. Various morpho-physiological parameters like plant height, peduncle length, 1000 grain weight and the number of grains per year were decreased in the late sown crop. However, Put application under HT stress increased these parameters. Overall, it appears that upregulation of the antioxidant system by Put in wheat cultivars contributes to the better protection and membrane integrity in the root, shoot and grains against HT through reduced MII and TBARs contents.

Nitric oxide alleviates oxidative damage induced by high temperature stress in wheat.

Effect of sodium nitroprusside (SNP), a donor of nitric oxide (NO) was examined in two wheat (Triticum aestivum L.) cultivars, C 306 (heat tolerant) and PBW 550 (comparatively heat susceptible) to study the extent of oxidative injury and activities of antioxidant enzyme in relation to high temperature (HT) stress. HT stress resulted in a marked decrease in membrane thermostability (MTS) and 2, 3, 5-triphenyl tetrazolium chloride (TTC) cell viability whereas content of lipid peroxide increased in both the cultivars. The tolerant cultivar C 306 registered less damage to cellular membranes compared to PBW 550 under HT stress. Activities of antioxidant enzymes viz, superoxide dismutase, catalase, ascorbate peroxidase, guaicol peroxidase and glutathione reductase increased with HT in both the cultivars. Following treatment with SNP, activities of all antioxidant enzymes further increased in correspondence with an increase in MTS and TTC. Apparently, lipid peroxide content was reduced by SNP more in shoots of heat tolerant cultivar C 306 indicating better protection over roots under HT stress. The up-regulation of the antioxidant system by NO possibly contributed to better tolerance against HT induced oxidative damage in wheat.

Fetus-in-fetu presenting as acute intestinal obstruction.

Fetus-in-fetu is a rare condition in which a fetiform calcified mass is often present in the abdomen of its host; a newborn or infant. We present the case of a three-month-old male baby with acute intestinal obstruction and abdominal mass. X-ray abdomen and ultrasonogram revealed a cystic mass with calcification. On laparotomy, a well encapsulated retroperitoneal mass causing high intestinal obstruction was identified. Total excision of the mass was done. Diagnosis of fetus-in-fetu was confirmed on histopathology. Postoperative recovery was uneventful.