Exorista sorbillans, the uzi fly, is a serious tachinid pest of silkworm and is present in all silk producing areas of Asia. Assuming that E.sorbillans was accidentally transported from West Bengal to southern states of India, its population genetic structure was studied using 13 ISSR, 3 RAPD, two sets of universal primers and two sets of primers designed from a lepidopteran repeat sequence. Statistical analyses of DNA markers revealed significant genetic variability between the E. sorbillans populations from 4 different geographic locations (within 400 km of one another) in the southern states and the one from West Bengal (Murshidabad). Multivariate and discriminant function analyses indicate that the E. sorbillans from south India has diverged from the original gene pool of West Bengal and is suitable for studying the microevolution of adaptation to the conditions prevailing in the different cocoon producing areas in India.
Abbreviations used. GP = geographic population; ISSR = Inter Simple Sequence Repeat; PCR = Polymerase Chain Reaction; RAPD = Random Amplified Polymorphic DNA; SPSS = Statistical Package for Social Sciences; UBC = University of British Columbia; UNIV = Universal.
Small GTPases of the Rab family are key regulators of membrane trafficking. Monoclonal antibodies are useful tools for identifying proteins that interact with other proteins and for examining their tissue distribution. We selected a monoclonal antibody against Rab8 of Bombyx mori L. It specifically recognized amino acid residues 30-109, which are conserved among Rab8 proteins, and did not recognize any other Rab proteins. Western blotting using the antibody revealed one band in the brains of B. mori and rat. Far-Western blotting analysis detected three proteins interacting with Rab8. These results indicate that this antibody is useful for clarifying the physiological function of Rab8 of B. mori and other species. This is a report of a study on a monoclonal antibody against insect Rab protein.
Small GTPases of the Rab family act as essential regulators of vesicle transport pathways. Five Rab cDNA clones (BRab1, 7, 8, 11 and 14) from Bombyx mori were expressed in Escherichia coli as a thioredxin or glutathione sulfotransferase fusion protein. After purification, the fusion protein was tested for phosphorylation using protein kinase C (PKC). Results indicate that all of them were phosphorylated in vitro. The phosphorylation site of BRab1 was determined by mass-spectrometric analysis, which identified that Ser-17 of BRab1 was phosphorylated by PKC. Deletion and site-directed mutagenesis indicated that Ser-111of BRab8, in addition to Ser-17, was newly phosphorylated. Further immunohistochemical analysis using antibodies against Rab8 indicated that there are some Rab8 immunoreactive cells close to the neuropeptide secreting cells. This result suggests that in insects Rab proteins are regulated by phosphorylation and at least some of them are involved in neuropeptide secretion.
Pyridoxal kinase (PLK; EC 2.7.1.35) is a key enzyme in the metabolism of vitamin B6 (VB6) in Bombyx mori. A fusion expressional vector pET-22b-BPLK-His was constructed using a sub-cloning technique, the recombinant B. mori PLK was then expressed in Escherichia coli, purified and characterized. Bioinformatics were used to deduce the protein structure and genomic organization of this enzyme. Using Ni Sepharose affinity column chromatography, the recombinant protein was purified to very high degree (approximately 90%). The recombinant PLK exhibits a high specific enzymatic activity (1800 nmol/min/mg of protein). The maximum catalytic activity of this enzyme was recorded over a narrow pH range (5.5-6.0) and Zn2+ is the most effective cation for catalysis under saturating substrate concentrations. When only triethanolamine is present as the cation, K+ is an activator of PLK. A double reciprocal plot of initial velocity suggests that the enzyme catalyses the reaction by means of a sequential catalytic mechanism. Under optimal conditions, the Km value for the substrates of ATP and pyridoxal are 57.9 ± 5.1 and 44.1 ± 3.9 µM. B. mori's genome contains a single copy of the PLK gene, which is 7.73 kb long and contains five exons and four introns, and is located on the eighth chromosome. The PLK may be a dimer with two identical subunits under native conditions, and it is hypothesized that each monomer contains eight α-helices (α1-8), nine β-strands (β1-9) and two segments of 310 helices. and Shuo-Hao HUANG, Wang MA, Ping-Ping ZHANG, Jian-Yun ZHANG, Yan-Feng XIE, Long-Quan HUANG.
Galleria mellonella larvae spin protective tubes, which they use until they finish feeding, when they spin cocoons. A feeding choice experiment showed that some of the silk produced by feeding larvae was consumed in addition to the standard diet (STD). To determine the effect of feeding on silk, last instar larvae were fed for 24 h on foods based on STD but modified by replacing the dry milk component (10% of the diet) with equal amounts of different kinds of silk. While each control larva consumed 21 ± 0.5 mg of the STD and produced 4.5 ± 0.1 mg of silk, larvae that ate the food that contained larval silk consumed 10 ± 0.4 mg of food and produced 6.1 ± 0.1 mg silk; the percentage ratio of silk produced to diet consumed was 21% and 61%, respectively. A more pronounced reduction in food consumption occurred when larvae were supplied with Galleria "cocoon" silk or the sericin fraction of such silk, and only 3.8 mg/larva was ingested of the diet containing Bombyx mori cocoon silk or its sericin fraction. Silk production expressed in terms of percentage of diet consumed was always higher than that recorded for larvae fed STD. We conclude that G. mellonella larvae recycle part of the silk that they produce during feeding. Presence of silk in the diet reduces food intake but increases the ratio of silk production to diet consumption. Sericin fraction of the cocoon silk seems to deter feeding., Haq Abdul Shaik, Archana Mishra, František Sehnal., and Obsahuje bibliografii
The Forkhead box O (FoxO) transcription factors, including FoxO1, FoxO3a, and FoxO4, have been implicated in the regulation of several biological processes, including stress resistance, metabolism, and apoptosis. In the present study, FoxO1 and FoxO3a patterns and their role in the regulation of the insulin signalling and mitogen-activated protein kinase (MAPK) pathways were analyzed after starvation in the fat body cells of the silkworm, Bombyx mori. FoxO1 and FoxO3a are localized to the nuclei. It was found that the levels of the insulin receptor and phosphoryated kinase Akt (p-Akt) increased when the animals ceased feeding. Starvation conditions caused a decrease in extracellular-signal-regulated kinase (ERK) phosphorylation, and an increase in c-Jun N-terminal kinase (JNK) and p38 (MAP kinase) phosphorylation. This implies that the FoxO transcription factors are activated by starvation and that starvation leads to changes in the insulin signalling and MAPK pathways in B. mori. These results strongly suggest that the FoxO transcription factor may be involved in the regulation of the insulin signalling and MAPK pathways in B. mori. As such, the findings provide molecular entomologists with valuable information on the molecular mechanism of the signalling pathways in postembryonic development ofthe silkworm., Jin Hee Kim ... [et al.]., and Obsahuje seznam literatury