Gamma radiation effect on the midgut bacteria of Plodia interpunctella and its role in organic wastes biodegradation

Abstract

This paper focuses on some factors that affect the gut bacterial communities of Plodia interpunctella and their role in the removal of plastic polymer concentrations to make a clean environment. Counting of midgut bacteria from P. interpunctella reared on different diets exhibited that wheat bran gave a significantly higher number of colonies than other diets (84 × 102 CFU/gut). Histological midgut studies on control fully grown larvae showed different shapes of epithelial cells, elongated or pyramidal, and few numbers of oval regenerative cells. Various secretions are released from the apical margin of the cells. The peritrophic membrane cannot be detected and large numbers of bacteria occupied the midgut lumen. While, irradiated larvae with 250 Gy revealed sever damaged midgut cells, some cells appeared swollen and the others fused as heterogeneous mass. Besides, ruptured of peritrophic membrane and very reduction in the bacterial population were appeared in the lumen. In this respect, two bacterial isolates were isolated from the midgut larvae and identified by 16S rRNA gene sequencing with accession number NR 146667.2 and NR 112686.1, as Enterobacter tabaci strain YIM Hb-3(B1) and Bacillus subtilis subsp. Spizizenii strain NBRC 101239(B2), respectively. Scanning electron microscopy analysis revealed alterations in the polyethylene during 60 days of incubation. Two bacterial strains showed damaging effects on plastic including cavities and pits on the surface of plastic pieces increased with the time of treatment. Moreover, the formation of carbonyl groups was verified using a fourier transform infrared imaging microscope.