<p style="text-align: justify;">Sorbitol Dehydrogenase (SDH) is important enzymes responsible for the protection of eggs from harsh condition as it convert fructose to sorbitol which serves as polyol and stabilize the soluble proteins and lipid bilayer. The enzyme SDH (d-Idiol NAD oxidoreductase EC 1.1.1.14) is purified from the eggs of red cotton bug, Dysdercus cingulatus exposed to low temperature. The SDH from eggs were purified by using different protein purification technique viz, ion exchange chromatography, gel filtration and SDS&ndash;PAGE. The ion exchange chromatography showed 0.185U total activity, with a purification fold of 1.48 and yield 3.36%. Gel filtration chromatography showed an increase in purification of SDH activity by 2.73 with 0.095 U total activity and yield of 1.73%. &nbsp;SDS-PAGE revealed that SDH molecular weight of 38 KDa. The Km value of Fructose: NADH is 0.4:0.01 and the Vmax was 0.6 and 0.03. Thus low temperature increases the activity of SDH which convert fructose to sorbitol which protects the cell during diapause condition.&nbsp;</p>


<p>Purification of sorbitol dehydrogenase from diapause eggs&nbsp;of <em>Dysdercus cingulatus</em> (fabricus 1775)</p>


<div style="text-align: justify;">The main objective of this study is the Population dynamics evaluation of broad bean bruchid Bruchus rufimanus (Coleoptera: Chrysomelidae) in crops beans of Vicia faba within the El Asnam&rsquo;s region (Algeria). A weekly monitoring of B. rufimanus was made during breeding diapauses in the laboratory and during their colonization in the parcel of variety of S&eacute;ville, and then a comparative study had been implemented to characterize the total haemolymphatic protein levels during diapause and the periods of reproductive activity. The obtained results demonstrated that after the diapause period, the colonization of the field by adults of B. rufimanus coincides with the period of full bloom of the host plant which represents a trophic source necessary for the reproductive activity. 54 beetles were captured from which 28 were males. Oviposition covering a period of one month and 15 days, with a total of 168 eggs being counted, of which 72 were placed on the low layer pods. The total hemolymphatic protein content of B. rufimanus was found a high concentration during diapause and varying between 46 to 85.8&igrave;g/&igrave;l. High levels of protein were probably due to the stock of proteins during the larval life of this pest. Protein levels had decreased significantly in April, reflecting a recovery in the activity and colonization of bean fields for food, sexual partnership, spawning, and other activities. However, throughout the month of May, the protein concentration increased due to the pollen supply provided by the host plant and weeds present in the agrosystem.</div>

Purification of sorbitol dehydrogenase from diapause eggs of Dysdercus cingulatus (fabricus 1775)

Monitoring the activity and biology of pest Bruchus rufimanus (Coleoptera: Chrysomelidae) in beans crops