C-reactive protein: a pentraxin with anti-acetylcholine activity

Purified C-reactive protein (CRP) diminished effects of acetylcholine (ACh) on the vascular tone and the heart rate of rats in vivo. In vitro CRP inhibited breakdown of ACh by acetylcholinesterase (AChE) while did not interact with AChE itself. CRP appears to bind ACh. CRP did not modify the cardiovascular effects of adenosine, another vasorelaxant. The data suggest that there is a new line of cross-talk between the inflammation and cholinergic regulation with CRP acting on endothelium via the ACh-dependent pathway.     

Structure of an amide bond forming F(420):gamma-glutamyl ligase from Archaeoglobus fulgidus -- a member of a new family of non-ribosomal peptide synthases

F(420) is a flavin-like redox-active coenzyme commonly used by archaea and some eubacteria in a variety of biochemical reactions in methanogenesis, the formation of secondary metabolites, the degradation of nitroaromatic compounds, activation of nitroimidazofurans, and F(420)-dependent photolysis in DNA repair. Coenzyme F(420)-2 biosynthesis from 7,8-didemethyl-8-hydroxy-5-deazariboflavin (Fo) and lactaldehyde involves six enzymatic steps and five proteins (CofA, CofB, CofC, CofD, and CofE). CofE, a F(420)-0:gamma-glutamyl ligase, is responsible for the last two enzymatic steps; it catalyses the GTP-dependent addition of two L-glutamate residues to F(420)-0 to form F(420)-2. CofE is found in archaea, the aerobic actinomycetes, and cyanobacteria. Here, we report the first crystal structure of the apo-F(420)-0:gamma-glutamyl ligase (CofE-AF) from Archaeoglobus fulgidus and its complex with GDP at 2.5 A and 1.35 A resolution, respectively. The structure of CofE-AF reveals a novel protein fold with an intertwined, butterfly-like dimer formed by two-domain monomers. GDP and Mn(2+) are bound within the putative active site in a large groove at the dimer interface. We show that the enzyme adds a glutamate residue to both F(420)-0 and F(420)-1 in two distinct steps. CofE represents the first member of a new structural family of non-ribosomal peptide synthases.     

Identification and Cloning of Peptide Synthetase Genes of Thermostable Bacilli Using the Polymerase Chain Reaction

Fourteen thermophilic and thermostable strains of the genus Bacillus were studied. Total DNA was isolated from these strains and used as a template to identify and clone peptide synthetase genes by means of polymerase chain reaction. Amplified DNA fragments were cloned into a phasmid vector, and nucleotide sequences of cloned fragments were determined. Stringent thermophilic strains were shown to lack genetic systems, which are responsible for the synthesis of secondary metabolites and homologous to the known peptide synthetase genes. On the contrary, thermostable strains had peptide synthetases and produced antimicrobial secondary metabolites. Analysis of nucleotide sequences and deduced amino acid sequences of cloned PCR fragments from B. licheniformis strains VK2, VK21, and VK2101 showed that they are absolutely identical. The cloned DNA fragment was found to be a portion of the open reading frame, which we termed ORF1. Data from analysis of a partial nucleotide sequence of the peptide synthetase gene of strain VK21 indicated that a 9.5-kb region of chromosomal DNA contains sequences of two genes homologous to the B. subtilis peptide synthetase genesdhbB and dhbF. Strains VK2, VK21, and VK2101 were shown to synthesize siderophores. A method for screening bacteria with peptide synthetase genes has been developed.     

Lectin histochemistry for detecting cadmium-induced changes in the glycosylation pattern of rat placenta

Cadmium (Cd) is an industrial and environmental pollutant that produces toxic effects on gametogenesis, pre- and post-implantation embryos, and the placenta. Because the effects of acute Cd intoxication on the placenta are not well understood, we investigated changes in its glycosylated components in Cd treated dams at days 4, 7, 10 and 15 of gestation using lectin histochemistry. CdCl₂ was administered to pregnant rats; control animals received sterile normal saline. Placentas were processed for DBA, Con A, SBA, PNA, UEA-I, RCA-I and WGA lectin histochemistry to evaluate changes in the carbohydrate pattern of the placenta that might modify cell interactions and contribute to embryonic alterations. Lectin binding was analyzed in the yolk sac; trophoblast giant cells; trophoblast I, II and III; spongiotrophoblast cells and endovascular trophoblast cells in the chorioallantoic placenta. Our lectin binding patterns showed that Cd caused alteration of SBA and DBA labeling of trophoblast-derived cells, which suggested increased expressions of α and β GalNAc. Cd also caused decreased UEA-1 binding affinity, which indicated fewer α-L-Fuc residues in placentas of Cd treated dams. The nonreactivity in trophoblast I of the control placentas incubated with Con-A contrasted with the labeling in placentas of experimental dams, which indicated increased expression of terminal α-D-Man, and α-D-Glc residues. We found that Cd altered the reactivity of placenta to several lectins, which indicated modification of the glycotype presented by the fetal component of the placenta. We report that Cd exerts a deleterious effect on the glycosylation pattern of the placenta.     

Fibrinolytic activity of bacteria from Pseudomonas genus]

A strain of the genera Pseudomonas genera was found to possess hemolytic, fibrinolytic and thrombolytic activities. The fibrinolytic activity of the lyophilized unpurified preparation was 900 conventional units/mg. After incubation in the blood plasma, the activity completely remained. The preparation (1 microgram/ml, 750 micrograms of protein) obtained by precipitation with ammonium sulfate (80% saturation) completely lysed in vitro human blood thrombi for 50 min. The strain studied can find practical applications in medical industry.     

Determination of optical activity of the growth medium as a method for detection of extraterrestrial life]

Determination of optical activity of the cultural medium can be used for detection of extraterrestrial life. The composition of the growth medium depends on the duration of the experiment. Automatic biological stations are sent to planets for a short time, and the best components of the growth medium are D-glucose and D-maltose; optical activity of the cultural broth disappears upon assimilation of these compounds. Tartaric acid is less suitable since the duration of the experiment increases several times and desert soils do not always contain microorganisms assimilating tartaric acid.