Helicoverpa are important polyphagous agricultural insect pests and they have a worldwide distribution. In this study, we report the bacterial community structure in the midgut of fifth instar larvae of Helicoverpa armigera, a species prevalent in the India, China, South Asia, South East Asia, Southern & Eastern Africa and Australia. Using culturable techniques, we isolated and identified members of Bacillus firmus, Bacillus niabense, Paenibacillus jamilae, Cellulomonas variformis, Acinetobacter schindleri, Micrococcus yunnanesis, Enterobacter sp., and Enterococcus cassiliflavus in insect samples collected from host plants grown in different parts of India. Besides these the presence of Sphingomonas, Ralstonia, Delftia, Paracoccus and Bacteriodetes was determined by culture independent molecular analysis. We found that Enterobacter and Enterococcus were universally present in all our Helicoverpa samples collected from different crops and in different parts of India. The bacterial diversity varied greatly among insects that were from different host plants than those from the same host plant of different locations. This result suggested that the type of host plant greatly influences the midgut bacterial diversity of H. armigera, more than the location of the host plant. On further analyzing the leaf from which the larva was collected, it was found that the H. armigera midgut bacterial community was similar to that of the leaf phyllosphere. This finding indicates that the bacterial flora of the larval midgut is influenced by the leaf surface bacterial community of the crop on which it feeds. Additionally, we found that laboratory made media or the artificial diet is a poor bacterial source for these insects compared to a natural diet of crop plant.

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Polylactic acid (PLA) is blended with native starch or thermo plasticized starch (TPS) for preparing biodegradable composites. However, poor compatibility of PLA with starch results in the composites with inferior mechanical properties. This study examines the effect of Maleic Anhydride-Grafted-PLA (GMAPLA) coupling agent and its concentration on the extent of improvements in mechanical and thermal properties of PLA –TPS blends. Maleic anhydride was grafted on PLA in Haake torque rheometer, characterized and used as the coupling agent. PLA/TPS (wt/wt) blends (70/30 and 50/50) were prepared by twin screw extrusion. GMAPLA at three different levels 5%, 10% and 15% (wt%) with respect to PLA content was taken to study its effect on mechanical properties of blends. Presence of GMAPLA significantly improved the mechanical properties (tensile, flexural and impact strength) of TPS/PLA blends. Among the three concentrations, 10% GMAPLA in the blend was found to give the maximum improvement in strength properties. Dynamic mechanical analysis and thermo-gravimetric analysis indicated no significant effect of GMAPLA content on transition temperatures and thermal degradation behavior of the blends.

The aloe vera plant has a long history of healing power. Recently, aloe vera has gained some popularity as an active natural product used in the medical and dental field for treating many diseases. It has various miraculous properties like anti-inflammatory, antibacterial, antiviral and antitumor which accelerates wound healing and helps in treating various lesions in oral cavity. Though, there are various indications for its use, more clinical research is required to determine its real efficacy in dentistry. The aloe vera plant, its composition, properties, mechanism of action and clinical uses are briefly reviewed in this article.

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