title: Isolation and characterization of lipase-producing bacteria in the intestine of the silkworm, Bombyx mori, reared on different forage.
abstract: The silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), an oligophagous insect that mainly feeds on mulberry leaves, is susceptible to entomopathogen infection when reared with tricuspid cudrania leaves. A total of 56 dominant bacterial strains, classified into 12 phylotypes based on bacteriological properties and analysis of 16S rRNA genes, were isolated from the intestine of the fourth and fifth instar silkworm larvae. Ten and seven phylotypes exist in the intestine of the silkworm larvae reared with mulberry leaves and tricuspid cudrania leaves, respectively. Four of them are common in the intestine of the two treatment groups. By screening their lipolytic ability on a Rhodamine B agar plate, nine lipase-producing bacterial strains were obtained and classified into six genera, including Bacillus, Brevibacterium, Corynebacterium, Staphylococcus, Klebsiella, and Stenotrophomonas. Except for Stenotrophomonas, which is common in both, the other genera only exist in the intestine of the silkworm larvae fed with mulberry leaves. In addition, by culture and fermentation in vitro, the maximum cell density and lipase activity of lipase-producing bacteria were examined at about 48 hours. The results indicate that diet has a significant impact on the gut bacterial community, especially lipase-producing bacteria. We suggest that the difference of lipase-producing bacterial diversity might be related to disease resistance of the silkworm.
authors.affiliation: Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing 400716, China. fengwei.sky@163.com
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.forename: Xiao-Qiang
authors.initials: XQ
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Guang-Ying
authors.initials: GY
authors.lastname: Liu
authors.forename: Yong-Ji
authors.initials: YJ
authors.lastname: Wan
mesh_terms: D000818:Animals; D001419:Bacteria / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D012831:Bombyx / Q000276:immunology / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D004032:Diet; D041981:Gastrointestinal Tract / Q000382:microbiology; D060434:Herbivory; D008049:Lipase / Q000032:analysis*; D029586:Moraceae; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D008049:Lipase