IOSR-JAVS   Volume-3 ~ Issue-3 ~ MAY-JUN-2013

ABSTRACT:Soft rot is a serious disease among vegetable crops that leads to high rate of economic loss to farmers. The disease is mainly caused by gram negative bacteria belonging to Pectobacterium species. The main symptom is necrosis due to degradation of cell wall by the activity of certain exo-enzymes (Plant Cell Wall Degrading Enzymes) which is produced by the bacteria in accordance with quorum sensing and signal transduction. The present study focused to control the synthesis of autoinducer called Acyl homoserine lactone, which modulates quorum sensing through the inhibition of Methionine S-adenosyl transferase (S-adenosyl methionine synthase) and Acyl homoserine lactone synthase enzymes. The inhibitory activities of Cycloleucine on Methionine S-adenosyl transferase and S-adenosyl methionine analogs on Acyl homoserine lactone synthase were studied by docking method using AutoDock 4.2. The results obtained indicate that the organic molecules used for the inhibition of targeted enzymes may be the best choice for the control of soft rot in vegetable crops.

Keywords: Soft rot, Quorum sensing, Cycloleucine, Pectobacterium carotovora, Docking.

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ABSTRACT:Theobjectivesofthepresentstudyweretoexaminetheeffectsofphotoperiodandlight colors on growth rate and activity of Nil Tilapia (Tilapia Niloticus).The fish were fed by hand a commercial feed (crude protein, 27%; crudelipid 5.06 %; crude fiber 5.08 %; total energy 4000 kcal/kg) for 60 days.The results indicated that photoperiod (24L:0D, 16L:8D and control) and light colors (white, red and blue) were significantly affected fish growth performance. The blue light was better than other colors lights, both at different photoperiods. The blue light and long light phase (24 light hours) produced the best fish percentage weight gain (WG = 1037.8 %), specific growth rate (SGR = 4.05 %), daily growth rate (DGR = 17.3 %) and growth efficiency (GE = 0.29). On the other hand, the blue light and light cycle 16L:8D gave weight gain (WG = 890.4 %), specific growth rate (SGR = 3.82 %), daily growth rate (DGR = 14.84 %) and growth efficiency (GE = 0.27). The lowest mean values of feed conversation ratio (FCR = 1.04) was observed in blue light and long light photoperiod. The highest mean values of feed conversation ratio (FCR = 1.19) was observed in blue light and 16L:8D light cycle.

Keywords: photoperiod, light colors, fish performance.

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