Profiling of proteins and proteases in the products of the salivary gland, digestive tract and excretions from larvae of the camel nasal botfly, Cephalopina titillator (Clark)

Proteins and proteolytic activities in the contents of the salivary gland (SGc), digestive tract (DTc) and excretory-secretory products (ESP) from larvae of the camel nasal botfly Cephalopina titillator were separated electrophoretically, and characterized. The protein profiles of the different samples were qualitatively quite similar in the larval stages L2 and L3. Zymogram analysis of proteases in the samples indicated that the digestive tract contained a greater variety of proteases than the salivary gland or the excretory-secretory products. They are mainly serine proteases. Proteases of ESP and DTc (especially of 3rd instar) contain trypsin- and chymotrypsin-like serine proteases, while the serine proteases of SGc are not of the trypsin- or chemotrypsin-type.

Biochemical characterisation of α-amylase in two aphid species, Aphis fabae Scopoli (Hemiptera: Aphididae) and A. gossypii Glover (Hemiptera: Aphididae)

We identify and characterise α-amylases of the two aphid species, A. fabae and A. gossypi. To do this, α-amylases of the two insect species were extracted and their activities were determined using 1% soluble starch. Results showed that α-amylase, which hydrolyses starch, is present in both aphids. Also, it was shown that optimum pH and temperature for the α-amylases of both species is 7.0 and 40°C, respectively. Gel assays using zymogram analysis showed that in both aphid species more than one isoform (two isoforms) of α-amylases hydrolyszing carbohydrates are present.  

A Broad-Spectrum Antimicrobial Activity ofBacillus subtilisRLID 12.1

In the present study, an attempt was made to biochemically characterize the antimicrobial substance from the soil isolate designated as RLID 12.1 and explore its potential applications in biocontrol of drug-resistant pathogens. The antimicrobial potential of the wild-type isolate belonging to the genusBacilluswas determined by the cut-well agar assay. The production of antimicrobial compound was recorded maximum at late exponential growth phase. The ultrafiltered concentrate was insensitive to organic solvents, metal salts, surfactants, and proteolytic and nonproteolytic enzymes. The concentrate was highly heat stable and active over a wide range of pH values. Partial purification, zymogram analysis, and TLC were performed to determine the preliminary biochemical nature. The molecular weight of the antimicrobial peptide was determined to be less than 2.5 kDa in 15% SDS-PAGE and in zymogram analysis againstStreptococcus pyogenes. The N-terminal amino acid sequence by Edman degradation was partially determined to be T-P-P-Q-S-X-L-X-X-G, which shows very insignificant identity to other antimicrobial peptides from bacteria. The minimum inhibitory concentrations of dialysed and partially purified ion exchange fractions were determined against some selected gram-positive and gram-negative bacteria and some pathogenic yeasts. The presence of three important antimicrobial peptide biosynthesis genesituc, fend,andbmybwas determined by PCR.

Expression of Trichoderma reesei β-Xylanase in Escherichia coli and its Function in Degradation of Juncao Holocellulose

In this study, the xyn2 gene, which encodes an endo-β-1,4-xylanase, was isolated with holocellulose extracted from Juncao Miscanthus floridulu as an inducer. The xyn2 gene expressed in Escherichia coli, with the estimated yield of 349 U·mL-1. Zymogram analysis showed that the purified Xyn2 had only one band on SDS-PAGE with an estimated molecular mass of 28 kDa. Enzymology analysis demonstrated that its optimum activity was at pH 6.0 and 60°C, with stability at pH range 4.0~7.0 and temperature up to 50°C. The metal ions Cu2+ and Mg2+ showed some inhibition effects, while Fe2+ and Fe3+ had small stimulating effects. Its values of Km and Vmax are 2.85 mM and 50.2 mM/min, respectively. Based on our results, we propose a novel way to convert Juncao biomass into energy and other useful products.