Current Science

Swati V. Roy ¹, Sachin N. Hajare ², Satyendra Gautam ², Deepti Deobagkar ¹, Arun Sharma ³

Affiliations
1 Centre of Advanced Studies, Department of Zoology, University of Pune, Pune 411 007, IN
2 Food Technology Division,Bhabha Atomic Research Center, Mumbai 400 085, IN
3 Food Technology Division, Bhabha Atomic Research Center, Mumbai 400 085, IN

Abstract

Sporulation in Bacillus sp. requires the death of spore mother cell that has been hypothesized to be genetically programmed. However, there is lack of conclusive evidence supporting this hypothesis. The present study provides evidence showing expression of programmed cell death (PCD)-specific markers such as activation of caspase-3, externalization of phosphatidylserine (PS) detected by annexin V-FITC binding through flow cytometry, and damage to DNA evaluated by TUNEL assay during sporulation in B. subtilis and B. megaterium. Addition of cell-permeable irreversible inhibitor of caspase -3 was found to inhibit the sporulation process as also the caspase-3 activity and PS externalization. These findings were further revalidated using sporulation-deficient-mutants of B. subtilis, created using chemical mutagenesis. These mutants were found to be deficient in caspase-3 activity as well as the extent of PS externalization. Wildtype B. subtilis cells were found to have extracellular metal-dependent DNAse activity, which decreased in sporulation-deficient mutants. These finding provide evidence for the existence and association of markers of PCD during sporulation-associated mother cell lysis in Bacillus sp.

Keywords

Bacillus Species, Mother Cell Lysis, Programmed Cell Death, Sporulation.

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Jyoti Tripathi ¹, Nilantana Bandyopadhyay ¹, Sachin N. Hajare ¹, Surbhi Wadhawan ¹, Haladhar Dev Sarma ², Satyendra Gautam ³

Affiliations
1 Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, IN
2 Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai 400 085, IN
3 Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094, IN

Abstract

Litchi fruit has recently been reported to be associat-ed with encephalopathy outbreaks in India due to presence of hypoglycaemic phytotoxins, hypoglycin A (HGA) and methylenecyclopropyl-glycine (MCPG). Therefore, a need was felt to determine safe tolerable dose of fruit based upon animal feeding studies. Swiss albino female mice (in each group, n = 6) were fed in both starved and unstarved conditions with maximum possible quantity of litchi pulp within 10 h duration at 2.5 h intervals (total quantity ~16 g). This did not re-sult in hypoglycaemia, weight loss or changes in be-haviour. Haematology profile, liver and kidney functions remain unchanged. Histopathological analy-sis of brain, liver and kidney too did not indicate any structural changes. From the reported range of above toxins in litchi pulp the quantity fed corresponds to the cumulative minimum concentration of 2.48 and ~9.0 mg/kg body weight of mice for HGA and MCPG respectively, which is lesser than LD₅₀ values of these toxins, i.e. 90–100 mg/kg body weight reported in rat. Thus based upon equivalent dose-quantity conversion, approx. 3.9 kg of litchi pulp/day for an adult human (weighing 60 kg) and 0.59–1.17 kg of pulp/day for children (1–5 years of age respectively) could be con-sidered a safe quantity.

Keywords

Blood Glucose, Brain, Haematology, Kidney, Liver, Organ Function Tests.

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