Size at birth and some sociodemographic factors in gypsies in Hungary

In 10,108 babies born to gypsy parents, birth weight, birth length and gestational age are compared with a national reference sample, taking into account maternal education, age, and birth interval. The gypsy babies tend consistently to be smaller, and this difference is attributable to the circumstances in which the gypsies live as well as the poorer maternal education. There appears to be a vicious circle--poor hygiene and living conditions adversely affect birth size, which in turn puts the child at a disadvantage in terms of survival, health and development.     

Morphological effects of the catechol estrogens on rat epididymal epithelia

The 2-hydroxy and 4-hydroxyestradiols (2-/4-OHE₂) caused marked cytotoxic effects, including vacuolation and nuclear changes, in rat epididymal epithelia, after exposure to very low levels (40 ng/rat/week) for 20 weeks. The effects of the 2-/4-OHE₂ metabolites were more pronounced than that of estradiol-17β(E₂).     

Development of screening methods for detection of carbohydrate-binding proteins by use of soluble glycosylated polyacrylamide-based copolymers.

Mammalian endogenous carbohydrate-binding proteins (lectins) play fundamental roles in a variety of mechanisms of interactions both at the molecular and cellular levels. We have investigated the binding of one of them (human brain lectin) to soluble acrylamide copolymerized with derivatives of either lactose (O-beta-lactosyloxyallylallylaminoacrylamide copolymer) or D-mannose (D-alpha-mannosyloxyallylallylaminoacrylamide copolymer) in direct enzyme affinoassays, in an attempt to develop simple procedures for detection and estimation of its carbohydrate-binding activity. Biotinylated plant lectins were utilized as reference standards. Affinoassays employed the polymer dotted on nitrocellulose and the polymer coated on microtiter plates as well as detection of bound biotinylated lectin by streptavidin/horseradish peroxidase reagent. Both assays provided reproducible binding, inhibitable by specific sugars. The microtiter plate assay is well suited to sensitive detection of the negative endogenous lectin by competition with biotinylated brain lectin. We conclude that the use of derivatized acrylamide in dotting and microtiter plate assays may prove practical for detection of endogenous lectins and that such polymers may serve as model substances in the study of biological partners of these carbohydrate-binding proteins.     

Purification and some characteristics of a beta-galactoside binding soluble lectin from amphibian ovary

Soluble extracts of Bufo ovaries agglutinate sialidase-treated rabbit erythrocytes. Unlike other amphibian lectins this agglutination activity does not require the presence of calcium ions. It is specifically inhibited by D-galactose and its derivatives. Thiodi-D-galactoside is the most potent saccharide inhibitor followed by lactose and methyl-beta-D-galactoside, respectively. D-Fucose, D-glucose and D-mannose do not inhibit the activity at concentrations at or above 100 mM. The lectin has been purified 500-fold to apparent homogeneity from the ovaries by salt extraction and affinity chromatography on lactose-aminophenyl-agarose, with a yield of about 0.2%. The molecular mass determined by gel filtration under native conditions was 30 kDa; polyacrylamide gel electrophoresis in SDS gave a molecular mass of 15 kDa, suggesting that the lectin is a dimer. The lectin has an isoelectric point of 40 and contains a high proportion of acidic amino acids.     

Some properties and the complete primary structures of two reduced and S-carboxymethylated polypeptides (S5C1 and S5C10) from Dendroaspis jamesoni kaimosae (Jameson's mamba) venom.

Two polypeptides (protein S5C1 and toxin S5C10) were purified from Dendroaspis jamesoni kaimosae venom. Whereas protein S5C1 comprises 61 amino acid residues, toxin S5C10 contains 58 and they each comprise four disulphide bridges. The complete primary structures of the two polypeptides have been elucidated. The sequences of protein S5C1 and toxin S5C10 are structurally homologous to the short neurotoxins Type I, but they are much less toxic. In toxin S5C10 one of the functionally invariant amino acid residues, lysine 26, of the Type I neurotoxin has been replaced by a serine. In contrast protein S5C1 has the feature that it contains ten or eleven structurally invariant amino acids and apparently only one of the five functionally invariant residues.     

Snake venom toxins--I. The primary structure of a long neurotoxin S4C6 from Aspidelaps scutatus (shield or shield-nose snake) venom

1. Long neurotoxin S4C6 from Aspidelaps scutatus venom was purified by gel filtration and ion exchange chromatography (Joubert, 1987). 2. It contains 68 amino acids including 10 half-cystines. The toxicity of toxin S4C6 was determined and a LD50 of 0.13 +/- 0.04 micrograms/g mouse was found. 3. The complete primary structure of long neurotoxin S4C6 has been elucidated. In the toxin the 10 structurally invariant amino acids of the neurotoxins and cytoxins and the five functionally invariant amino acids of the neurotoxins are conserved.     

Studies of the Extracellular Glycocalyx of the Anaerobic Cellulolytic Bacterium Ruminococcus albus 7

Anaerobic cellulolytic bacteria are thought to adhere to cellulose via several mechanisms, including production of a glycocalyx containing extracellular polymeric substances (EPS). As the compositions and structures of these glycocalyces have not been elucidated, variable-pressure scanning electron microscopy (VP-SEM) and chemical analysis were used to characterize the glycocalyx of the ruminal bacterium Ruminococcus albus strain 7. VP-SEM revealed that growth of this strain was accompanied by the formation of thin cellular extensions that allowed the bacterium to adhere to cellulose, followed by formation of a ramifying network that interconnected individual cells to one another and to the unraveling cellulose microfibrils. Extraction of 48-h-old whole-culture pellets (bacterial cells plus glycocalyx [G] plus residual cellulose [C]) with 0.1 N NaOH released carbohydrate and protein in a ratio of 1:5. Boiling of the cellulose fermentation residue in a neutral detergent solution removed almost all of the adherent cells and protein while retaining a residual network of adhering noncellular material. Trifluoroacetic acid hydrolysis of this residue (G plus C) released primarily glucose, along with substantial amounts of xylose and mannose, but only traces of galactose, the most abundant sugar in most characterized bacterial exopolysaccharides. Linkage analysis and characterization by nuclear magnetic resonance suggested that most of the glucosyl units were not present as partially degraded cellulose. Calculations suggested that the energy demand for synthesis of the nonprotein fraction of EPS by this organism represents only a small fraction (<4%) of the anabolic ATP expenditure of the bacterium.