Immobilization of ovomucoid on chitosan

The inhibitory activity of ovomucoid from duck egg white, immobilized on chitosan with the use of glutaraldehyde or carbodiimide as cross-linking agents, was studied. Glutaraldehyde proved to be a more preferable cross-linking agent than carbodiimide. When chitosan is used as a protein carrier, the possibility of shifting the pH optimum of these compounds should be taken into account.     

Genbank accession #: AJ131961

Plant Molecular Biology -     

Parameters of in vitroEvolution of Proteins and Peptides

In vitroevolution is used to study protein sequences, structures, and interactions and to obtain proteins with new properties. To analyze the specific features of this process in phage display experiments, we studied the amino acid composition of selected sequences, constructed a matrix of amino acid substitutions, and identified pairs of coadaptive substitutions. The amino acid frequency proved to be tightly associated with the number of corresponding codons; numerous correlated substitutions were found.     

Protandrous migration and variation in morphological characters in Emberiza buntings at an East Asian stopover site

The effect of the timing of spring migration on reproductive success differs between the sexes. As a consequence, various sex‐specific tactics relating to the timing of migration have evolved in migratory avian groups. Various hypotheses have been proposed to explain differential migration to breeding or wintering grounds, and inter‐ and intrasexual size differences are often considered one of the proximate mechanisms. We investigated arrival patterns in the spring by individuals of each sex, sexual size dimorphism and related morphological variables, and the relationship between size variation and arrival date in five bunting species that passed through an East Asian migratory flyway stopover site in 2006–08. Males of all the study species arrived before females, and significant sexual dimorphism was observed. Several morphological characters, including total length, wing‐length and tail‐length, contributed to the size variation. Although larger males arrived earlier, there was no relationship between arrival date and size in females. Our study confirmed that East Asian buntings display a discriminated protandrous migration pattern at the stopover site as well as at the breeding grounds. This is consistent with the view that larger body size in males is favoured due to its association with early arrival to help ensure access to the best resources and hence enhanced mating success.     

Effect of porcine placenta steroid extract on myogenic satellite cell proliferation, transdifferentiation, and lipid accumulation

Intramuscular long-chain fatty acids (LCFAs) play an important role in energy production and initiation of mitochondrial oxidation of lipids. Herein, we report a natural porcine placenta steroid extract (PPSE) that stimulates transdifferentiation and lipid accumulation in bovine myogenic satellite cells (MSCs). The steroids hormones in PPSE were analyzed using enzyme-linked immunosorbant assay and presence of LCFA was established using gas chromatography. At 70% confluent growth, cells were treated with PPSE, LCFAs, transdifferentiation cocktail and commercially available steroid hormones. The working concentrations of all chemicals were manipulated similar to PPSE. The cells were observed for morphological changes and subjected to quantitative analysis of lipid deposition on Days 2, 4, and 6 of treatment. PPSE-treated MSCs exclusively transformed into lipid-accumulated adipose-like cells (ALCs). However, myotubes or adipocytes were formed in cells treated with other chemicals. Expression of different genes was studied to ascertain the molecular mechanism involved in ALC formation. CD36, fatty acid binding protein 4, and peroxisome proliferator-activated receptor-gamma were up-regulated. The expression of CD36 was established through immunocyto-chemical analysis. A viability assay was used to confirm the effect of PPSE on proliferation of MSCs. Hence, a natural steroid extract from porcine was found as a nontoxic mixture, which induces lipid accumulation and transdifferentiation of MSCs to ALCs. From the gene expression studies, it was established that the extract works almost in homogenous manner with other lipid inducers.     

Chemical modification of proteins by "smart" polymers

The modification of proteinase inhibitor ovomucoid from duck eggs white by poly-N,N-diethylacrylamide having a low critical solution temperature (LCST) have been studied. Modification of free amino groups of lysine and N-terminal residue of ovomucoid is resulted in a significant decrease in the activity of the inhibitor toward trypsin and small decrease in the activity toward α-chymotrypsin. At heating of the solution of modified ovomucoid above the LCST transformation of the antitryptic centers of ovomucoid in antichymotryptic centers was observed. It was shown that this phenomenon is due to the hydrophobization the lysine residues localized in the reactive centers of the inhibitor while maintaining the structure of the "linkage loops". Therefore the α-chymotrypsine molecules began to interact with these residues, mistaking them for the residues of hydrophobic amino acids of antichymotryptic centers.     

Covalent immobilization of the pancreatic trypsin inhibitor on a polymeric carrier

Covalent immobilization of the pancreatic trypsin inhibitor onto a polymeric carrier was accomplished by introducing a double C = C bond in the inhibitor with a subsequent copolymerization of the activized inhibitor with acrylamide and N,N'-methylenebisacrylamide. To prevent a loss of the antitryptic activity under acylation of lysine residues of the reactive centre, the inhibitor was preliminary bound to a complex with trypsin, which was destructed by acidifying the solution before copolymerization. The antitryptic activity of the immobilized inhibitor was shown to be equal to the activity of the inhibitor in the native state.