Effect of certain entomopathogenic fungi on oxidative stress and mortality of Periplaneta americana.

The present paper reports the effects of Metarhizium anisopliae, Isaria fumosoroseus and Hirsutella thompsonaii on Periplaneta americana. I. fumosoroseus and H. thompsonaii were cultured at 28±1°C on potato carrot agar and M. anisopliae was cultured at 28±1°C on potato dextrose agar for 14days. Conidial suspensions of fungi were given to cockroaches through different routes. M. anisopliae shows high virulence against adult cockroaches and mortality ranges from 38.65% to 78.36% after 48h. I. fumosoroseus and H. thompsonii show less virulence compared to M. anisopliae. We also investigated the effect of these three fungi on the activity of lactate dehydrogenase, lipid peroxidation and catalase in different tissues of the insect to gain an understanding of the different target site. The result suggested that the activity of lactate dehydrogenase, catalase and level of malondialdehyde varies in different organs and through different routes of exposure. Based on mortality percentages, all tested fungi had high potentials for biocontrol agents against P. americana. Our study reveals for the first time that I. fumosoroseus and H. thompsonaii fungal infections initiate oxidative stress in the midgut, fat body, whole body and hemolymph of cockroach thereby suggesting them to be the target organs for oxidative damage.

A comparative study of the histology of the neurosecretory system of some orthopteran insects.

Variability of the total number of type A median neurosecretory cells in the protocerebrum was studied in Micapoda elongata Linn., Elima securigera Brunn., Holochlora indica Kirby, Neoconocephalus pallidus Reclt., Latana inflata Brunn., Gryllotalpa africana Chopard, Gryllus bimaculatus De Geer, Chrotogonus oxypterus Blanchard, Aeolopus affinis Bol., Spathosternum prasiniferum Walker, Hieroglyphus furcifer Ser., Acrida exaltata Walker, Altrastomorpha cranulata Fab., Pyrgomorpha bispinosa Walker, Cyrtacanthacris ranacea Stoll and Poecilocerus pictus Fab. In all these species the corporata allata are paired.

Studies on the proteins of Poecilocera picta. I-changes taking place in the haemolymph protein during moulting.

The haemolymph proteins of the 6th nymph of P. picta were fractioned by the polyacrylamide gel disc electrophoresis. A total of seven proteins fractions have been detected from the haemolymph. The chemical nature of different protein fractions have been examined by histochemical methods. The changes taking place in the cuticle and epidermal cells have been examined during the transformation of 6th nymph into adult. The fat body proteins have been electrophoretically fractioned and the changes in the concentration of different protein fractions have been examined. It is suggested that the protein fraction 3 of the haemolymph is utilized in the formation of new cuticle. It is concluded by the histochemical observations that proteins of the band 3 are synthesized in the fat body.

Studies on the proteins of Poekilocerus pictus. II--changes taking place in the haemolymph protein during maturation of female.

In all, 7 protein fractions have been detected in the haemolymph of Poekilocerus pictus by the polyacrylamide gel disc electrophoresis. Out of seven protein fractions, four fractions i.e.3,4,5 and 6 take major role in the vitellogenesis. These fractions are accumulated in the ovariectomised female insect. No yolk is deposited in the allatectomised female ovary. The protein fractions 4, 5 and 6 show high concentration of protein in the allatectomised female as compared to the show operated female. It is concluded that the synthesis of protein fraction 3 is controlled by the corpora allata while the fractions 4, 5 and 6 are controlled by the neurosecretory cells.

Studies on the proteins of Poekilocerus pictus. III-changes taking place in the haemolymph protein during maturation of male.

In all 7 protein fractions have been detected in the haemolymph of Poekilocerus pictus by the Polyacrylamide gel disc electrophoresis. Out of seven protein fractions, four fractions i.e. 3, 4, 5 and 6 take major role in the maturation of testis. Accumulation of proteins has been observed in the castrated insect. The concentration of the protein decreases and the size of the testis follicle remains small as compared to the normal male in the allatectomised insect. It is concluded that the proteins are selectively incorporated in the testis. It also appears that the synthesis of proteins and the maturation of testis is controlled by the allatum.

Changes in the haemolymph protein pattern during ovarian maturation in Xylocopa litipes.

The haemolymph proteins of a hymenopteran insect Xylocopa litipes have been fractioned by the polyacrylamide gel disc electrophoresis. The haemolymph protein fractions have been examined histochemically. The changes taking place in the haemolymph protein pattern during vitellogenesis have been studied. Common protein fractions were observed in the haemolymph, fat body, ovary and testis. The role of sex specific protein during the vitellogenesis has been discussed.

Changes taking place in the electrophoretic haemolymph protein pattern during metamorphosis of Polytela gloriosae (Lepidoptera).

The haemolymph proteins of the larva, pupa and adult of Polytela gloriosae have been fractioned by Polyacrylamide gel disc electrophoresis. In the haemolymph of the fifth instar larval stage a total of ten protein fractions have been detected. The concentration of the protein fractions 2, 3, 4, 9 and 10 shows oscillations in their concentration in the early fifth instar, middle fifth instar and late fifth instar larval stage. In all 11 protein fractionswere detected in the haemolymph of different stages of the pupa. The protein bands 1, 7 and 10 of the pupa appear newly in the haemolymph as these bands were not found in the haemolymph of the larvae. The protein fraction 9 of larva was not found in the pupa. In the haemolymph of adult insect sexual difference was observed in the haemolymph protein pattern. In the haemolymph of adult female a total of 10 protein fractions were detected while from the male haemolymph a total of 8 protein fractions were detected. The pupal band 7 was not found in the adults of both the sexes. In the haemolymph of larva and adult one pigmented protein fraction was observed. No pigmented protein fraction was found in the haemolymph of pupa. Iron - containing protein fraction and the acid mucopolysaccharides were not found in the haemolymph. The protein fractions 3, 4, 5, 6 and 7 of adult haemolymph were darkly stained by the Schiff reagent and, thus, they are the fractions of glycoprotein. One protein fraction of lipoprotein was also found in the haemolymph.