Complex regulation of the activity of ilv genes in Escherichia coli K-12 cells

The modern data on Escherichia coli K-12 ilv genes expression are reviewed. The problems of regulation of the ilv genes activity and of their possible role in the process of cell adaptation to changeable environment are discussed.     

Chymotrypsin adsorbed to a polyethylene terephtalate support (SORSILEN) as a suitable model for the investigation of enzymatically catalyzed organic syntheses in nonaqueous media

Summary The kinetics of acetyl-L-tryptophan esterification by ethanol in an organic solvent immiscible with water (chloroform) and catalyzed by chymotrypsin adsorbed from aqueous solution to a polyethylene terephthalate copolymer (SORSILEN) was examined by HPLC. The esterification yield (in %) increased with the decreasing concentration of the substrate and with the increasing activity of immobilized chymotrypsin. It has been shown that there was no chymotrypsin leakage from the aqueous phase on the support surface during the catalysis.     

The effect of small concentrations of antibiotics blocking the synthesis of bacterial cell wall on the permeability of Escherichia coli cell wall for plasmid DNA

Short treatment of Escherichia coli cells with antibiotics disturbing synthesis of bacterial cell wall in small concentrations renders the cells capable of absorbing foreign plasmid DNA. A novel express-method for transformation of E. coli cells by plasmid DNA has been developed on the basis of the results obtained. The whole procedure can be performed at room temperature. Depending on cell strain and the plasmid size, the efficiency of transformation can vary from 1.10(4) to 5.10(5) transformants per 1 mkg of DNA. The method suggested improves significantly the every-day work aimed at constructing plasmids.     

Characterization of β-amylase alleles in 79 barley varieties with pyrosequencing

β-Amylase is involved in the starch degradation process and therefore influences grain quality. Starch degradation efficiency is dependent on the enzyme thermostability during malting and mashing. Four alleles resulting in different enzyme thermostability are known. These alleles are distinguished by coding single nucleotide polymorphism (cSNP). Pyrosequencing was used for cSNP genotyping of β-amylase alleles in 79 spring barley varieties by using analyser PSQ MA96 System (Pyrosequencing, Biotage). A new cSNP was revealed by means of Pyrosequencing analysis of sequence flanking cSNP⁶⁹⁸, thus recognizing a fifth β-amylase allele. Pyrosequencing is a high-throughput, fast, and precise system for barley SNP genotyping.     

Cyanobacteria — a neglected component of biodiversity: patterns of species diversity in inland marshes of northern Belize (Central America)

Cyanobacterial mats, widely distributed in the inland alkaline marshes of northern Belize and other regions in the Caribbean, are not only important and functionally complex components of these habitats, but they are also significant reservoirs of biological diversity. Highly diverse and (relatively) isolated marshes have provided conditions suitable for cyanoprokaryotic organisms and conditioned the adaptation and stabilization of numerous specialized eco‐ and morphotypes. Species richness of cyanobacteria assemblages follows the conductivity gradient and is highest in the marshes of medium conductivity (c. 1000–2000 µS cm^?1) and decreases at low (< 500 µS cm^?1) and high (> 3000 µS cm^?1) conductivities. This ecologically unique cyanobacterial microflora is very sensitive to nutrient enrichment, both directly and indirectly through shading by expanding macrophytes. Species richness of cyanobacterial assemblages decreases dramatically as a result of eutrophication. Similar cyanobacterial communities are widely distributed in limestone‐based areas of Florida, Central America and Caribbean but none of them is currently under any legal protection status. The purpose of this paper is to bring attention to an ecologically important group of organisms that have traditionally not been considered in species diversity evaluations or conservation efforts.     

Polyclonal anti-chymotrypsin antibodies suitable for oriented immobilization of chymotrypsin

Summary Polyclonal antibodies obtained from the serum of pig immunized by DIP-chymotrypsin were separated into two fractions, anti-chymotrypsin IgG I and anti-chymotrypsin IgG II, by the use of chromatography on biospecific adsorbents prepared by chymotrypsin (CHT) immobilization in different ways. IgG I, which did not decrease the proteolytic activity of CHT, was obtained by biospecific affinity chromatography on a column of Sepharose with CHT attached through an immobilized polyvalent inhibitor, antilysin (AL). IgG II was isolated from the fraction unretarded on the column of CHT-AL-Sepharose by chromatography on a column with CHT directly attached to AH-Sepharose activated by glutaraldehyde. IgG II strongly decreased the proteolytic activity of CHT. Comparison of the proteolytic activity of CHT covalently bound to AH-Sepharose with that of CHT noncovalently intercepted by biospecific sorption to Sepharose with attached anti-CHT-IgG I showed a great advantage of the immobilization of CHT by oriented adsorption.     

Stabilization of trypsin by glycosylation

Summary The stabilization of trypsin against thermal inactivation and autolysis was achieved by coupling saccharides to lysine residues of the enzyme. The reaction of reductive amination was used to bind reducing disaccharides. Periodate oxidized saccharide residues of the modified protein were used for coupling of trypsin to solid supports containing amino or hydrazide groups.