On the abiotic formation of amino acids I. HCN as a precursor of amino acids detected in extracts of lunar samples II. Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples

Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is demonstrated. The second study investigates the formation of hydrogen cyanide as well as amino acids from lunar-sample gas mixtures under electrical discharge conditions. These results extend the possibility of synthesis of amino acids to planetary bodies with primordial atmospheres less reducing than a mixture of methane, ammonia, hydrogen and water.     

Diffusion of Mn2+ ions into liposomes mediated by phosphatidate and monitored by the activation of an encapsulated enzymatic system

Summary Transbilayer diffusion of Mn²⁺ ions occurred in liposomes formed from dipalmitoyl-phosphatidylcholine or egg-yolk phosphatidylcholine and egg-yolk phosphatidate (molar ratio 21) containing DNA and DNase I within their aqueous compartments. Cation diffusion was demonstrated by the hydrolytic activity of DNase I, activated by the Mn²⁺ ions that diffused into the vesicles, and this was confirmed by light scattering. Phosphatidate, a cone-shaped lipid which has been synthesized under simulated prebiotic conditions, was necessary for cation diffusion across the liposome membranes. Such liposomes represent a simple precellular system that interchanges cations with the surroundings and provides a microenvironment for enzymatic reactions, as evidenced by the hydrolysis of DNA by DNase I inside these closed lipid compartments.     

Clinical examination of diabetic patients treated with monocomponent insulin manufactured by MP Polfa

An effect of replacing conventional forms of insulin by the monocomponent insulin manufactured by "Polfa" was studied in the group of 22 diabetics. The patients were followed up for 12 months. An effect of monocomponent insulin on daily requirement of insulin, levels of anti-insulin, monocomponent and pancreatic peptide antibodies, compensation of diabetes mellitus, and lipodystrophy were investigated. New insulin preparation decreased anti-insulin and pancreatic peptide antibodies level and markedly diminished lipodystrophy. However, daily insulin requirement, degree of diabetes mellitus compensation, and anti-proinsulin antibodies level remained unchanged.     

Histochemical differentiation of peroxidase-mediated from tyrosinase-mediated melanin formation in mammalian tissues

Summary Preincubation with the copper-chelator, sodium diethyldithiocarbamate (DDC) and the presence of catalase in the incubation media allowed an accurate and reproducible differentiation of the role of tyrosinase from that of peroxidase in the oxidation of tyrosine and dopa in melanocytes, mast cells and eosinophils. These studies indicated that mammalian peroxidase in melanocytes, mast cells and eosinophils can mediate the conversion of tyrosine to melanin in the presence of dopa co-factor, as well as the conversion of dopa to melanin. With the methods employed, there was no evidence that tyrosinase in the preparations studied had significant ability to mediate the oxidation of tyrosine to melanin (even in the presence of dopa co-factor), although there was abundant evidence that it can mediate the conversion of dopa to melanin. Mammalian peroxidase may have roles in initiating melanin synthesis and catechol amine synthesis in vivo.Supported by USPHS Grant T1 AM 5,220, The General Research Support Fund, Boston City Hospital, and The Pathology Research Fund, St. Vincent Hospital.     

Experimental study of muscle permeability under various loading conditions

Biomechanics and Modeling in Mechanobiology - The permeability of a few muscle tissues under various loading conditions is characterized. To this end, we develop an experimental apparatus for...     

Composition and dynamics of the gill microbiota of an invasive Indo-Pacific oyster in the eastern Mediterranean Sea

Gill bacterial communities of Chama pacifica, an Indo-Pacific invasive oyster to the eastern Mediterranean Sea, were compared with those of Chama savignyi, its northern Red Sea congeneric species. Summer and winter bacterial populations were characterized and compared using 16S rDNA clone libraries, and seasonal population dynamics were monitored by automated ribosomal intergenic spacer analysis (ARISA). Clone libraries revealed a specific clade of bacteria, closely related to marine endosymbionts from the Indo-Pacific, found in both ecosystems, of which one taxon was conserved in oysters from both sites. This taxon was dominant in summer libraries and was weakly present in winter ones, where other members of this group were dominant. ARISA results revealed significant seasonal variation in bacterial populations of Mediterranean Sea oysters, as opposed to Red Sea ones that were stable throughout the year. We suggest that this conserved association between bacteria and oyster reflects either a symbiosis between the oyster host and some of its bacteria, a co-invasion of both parties, or both.