Characterization of proteins and trehalose as heat shock regulators in insect system
| dc.contributor.advisor | Mani, Chellappan | |
| dc.contributor.author | Swetaleena, Tripathy | |
| dc.contributor.author | KAU | |
| dc.date.accessioned | 2017-08-10T09:50:49Z | |
| dc.date.available | 2017-08-10T09:50:49Z | |
| dc.date.issued | 2008 | |
| dc.description.abstract | The study entitled “Characterization of proteins and trehalose as heat shock regulators in insect system” was undertaken in the laboratory of Centre for Plant Biotechnology and Molecular Biology and Department of Entomology, College of Horticulture, Kerala Agricultural University in Vellanikkara to study the underlying mechanism of the red flour beetle, Tribolium castaneum Herbst. (Tenebrioniidae: Coleoptera) to resist stress. Tribolium castaneum had been seen as a serious pest of flour mills and food processing industries causing huge loss every year. The use of elevated temperatures had long been recognized as an effective strategy for managing the dreaded stored product insect. The major objectives of the study were to find out the thermal death stage of the red flour beetle when exposed to a particular temperature and time period at which the insect was unable to combat stress further and to characterize the metabolites responsible for the survival of this insect during anhydrobiosis. The mass culturing of the insect was done at a temperature of 28°C with 70 per cent relative humidity. The population built up was faster on the wheat flour (30.97±0.20) followed by the combination of both wheat flour and semolina (30.91±0.15) while it was less in semolina alone (30.29±0.13). At the same time, the per cent contamination and per cent mortality were significantly more on wheat flour (41.3±3.53 and 19.58±0.93) when the relative humidity was higher (88%). The per cent contamination and per cent mortality were positively correlated with the temperature and relative humidity. The insect completed its life cycle within 34-38 days in the present study. Different stages of insects (neonates, V instar grub, pupae and the adult beetles) were subjected to temperatures ranging from 35°C to 60°C at an incremental increase of 5°C for a period of 1 h, 2 h and 4 h respectively. The insects were not killed even at 4h exposure to the above temperatures. However, the mortality of each stage of the insects was increased with the exposure time and the incremental temperature increase. A higher mortality per cent was observed at 50°C for 8 h (98.7±0.33) and 55°C for 6 h (90.7±0.67) respectively. Complete mortality of the insect was observed at 55°C and 60°C when the insect stages were exposed to the temperature for 7 h and 5 h respectively. Subjecting the insects to stress showed accumulation of a heat shock protein (hsp) along with an insect sugar called trehalose. It was observed that the heat shock protein and trehalose content in insects increased significantly with the stress. When the insects were exposed to 50°C, the corresponding protein content was in the order of neonate (36.81 mg/g) < pupa (38.16 mg/g) < adult (39.23 mg/g) < V instar grub (40.81 mg/g). Thus, the decrease in the total protein content was observed to be more for the neonate at 50°C when compared to the other stages. Similarly, when the insects were subjected to heat stress at 35°C, the trehalose content in the neonate sample was (14.97 mg/g) and it was significantly higher in V instar grub (16.49 mg/g), pupa (17.64 mg/g) and the adult (18.48 mg/g). But there was significant decrease in the trehalose content of the insect after the recovery of the stress period. The molecular weight (70KDa) of the ‘Trib hsp’ was determined from the SDS-PAGE analysis and its identity was further confirmed by the N-terminal sequencing. It showed 80 per cent homology with the heat shock protein. Further theoretical analysis of the protein sequence showed that the protein was stable and it was composed of four conserved domains. The data generated so far could be useful in developing a heat control strategy to manage this insect. Further studies with respect to characterization of anti heat shock protein could also be carried out in order to see its effect on a heat shock cognitive. The characterization of the stress regulators would help to manage the public health pest’s viz., mosquito. The genes coding for stress regulatory proteins could also be isolated, cloned and used for development of genetically modified insects. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810028324 | |
| dc.keywords | Plant Biotechnology and molecular Biology | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | College of Horticulture, Vellanikkara | en_US |
| dc.sub | Plant Biotechnology | |
| dc.subject | null | en_US |
| dc.theme | heat shock regulators in insect system | en_US |
| dc.these.type | M.Sc | en_US |
| dc.title | Characterization of proteins and trehalose as heat shock regulators in insect system | en_US |
| dc.type | Thesis | en_US |