Joseph Nagyvary

Compartmentalization of amino acids in surfactant aggregates - Partitioning between water and aqueous micellar sodium dodecanoate and between hexane and dodecylammonium propionate trapped water in hexane

SummaryCationic amino acids, arginine and lysine partition differentially from water into aqueous micellar sodium dodecanoate. Conversely, partitioning of serine, glycine, aspartic acid, glutamic acid, threonine, alanine, proline, valine, leucine, phenylalanine and isoleucine do not vary appreciably. Partitioning from neat hexane into dodecylammonium propionate trapped water in hexane is, however, dependent upon both electrostatic and hydrophobic interactions. These results imply that the interior of dodecylammonium propionate aggregates is negatively charged and is capable of hydrogen bonding in addition to providing a hydrophobic environment. The solubilities of amino acids in neat hexane substantiate the previously derived amino acid hydrophobicity scale. Relevance of partitioning in these systems to the postulated selective amino acid compartmentalization is discussed.

Wood used by Stradivari and Guarneri

Whether or not the great Italian violin-makers used wood that had been chemically processed in order to preserve it and enhance the instruments sound quality has long been a contentious issue. Here we use nuclear magnetic resonance and infrared spectroscopy to analyse organic matter in wood taken from antique instruments made by Stradivari and Guarneri del Gesu. Our results indicate that the wood used by the masters could indeed have been chemically treated, a technique that may inspire an approach to violin making that is more chemistry-based.

Origin of the Genetic Code: A Physical-Chemical Model of Primitive Codon Assignments

Selective compartmentalization of amino acids and nucleotides according to their polarities is proposed as a physical-chemical model for the origin of the genetic code. Assumptions made in this hypothesis are: (1) an oil-slick covered the surface of the primitive ocean, constituents of which formed association colloids or micelles at the water-oil-air interfaces; (2) depending on the polarity of the media, these aggregates possessed hydrophilic and hydrophobic interiors where selective uptake of amino acids and nucleic acid constituents could take place; and 93) condensation and polymerization in the micellar phase were enhanced. According to the chromatographically observed polarities, for example, lysine and uridylate fall into the hydrophilic compartment, and phenylalanine and adenylate are enriched in the hydrophobic environment. These components could eventually be condensed to form a charged adaptor loop with an anticodon which is complementary to the presently valid codon. Only two groups of amino acids, hydrophilic and hydrophobic, were recognized by the primitive translation mechanism. Implications of this hypothesis for the further development of the genetic code is discussed. The catalytic power of micelles have been substantiated by successful synthesis of nucleotides under relatively mild conditions using thiophosphates as high energy phosphates.

Studies on neutral esters of cyclic AMP

Summary Methyl and ethyl esters of cyclic AMP were obtained by a straightforward triesterification procedure. Both compounds are resistant to enzymes and undergo slow chemical hydrolysis at physiological pH. P-O-Methyl diacetyl cyclic AMP was found more toxic than the parent compound on Ehrlich ascites carcinoma cells, Chinese hamster ovary cells, and chick embryo fibroblasts in vitro . Both the methyl and ethyl esters, but not cyclic AMP, exhibited a significant inhibition of Ehrlich ascites carcinoma in vivo . It is proposed that triesters of cyclic AMP represent an ideal storage form of cyclic AMP and could be useful in a great variety of physiological studies.

Hypocholesterolemic effect of Al3+ complexes.

Summary We are proposing a simple model by which acidic polysaccharides of the critical charge density 1 minus/1 carbohydrate unit can be converted into anion exchangers by complexing with a trivalent cation. We have constructed a complex of alginic acid and Al3+ which was shown to bind nucleotides. It was assumed that bile acids would also be bound and, thus, Al- alginate would be hypocholesterolemic in vivo . The feeding of Al- alginate to rats which were fed a high cholesterol diet produced a marked decrease of serum cholesterol. It is proposed that Al3+ may have a nutritional role if present in conjunction with acidic polysaccharides. Ternary complexes involving lipids may exist in many biological structures.

Mineral Preservatives in the Wood of Stradivari and Guarneri

Following the futile efforts of generations to reach the high standard of excellence achieved by the luthiers in Cremona, Italy, by variations of design and plate tuning, current interest is being focused on differences in material properties. The long-standing question whether the wood of Stradivari and Guarneri were treated with wood preservative materials could be answered only by the examination of wood specimens from the precious antique instruments. In a recent communication (Nature, 2006), we reported about the degradation of the wood polymers in instruments of Stradivari and Guarneri, which could be explained only by chemical manipulations, possibly by preservatives. The aim of the current work was to identify the minerals from the small samples of the maple wood which were available to us from the antique instruments. The ashes of wood from one violin and one cello by Stradivari, two violins by Guarneri, one viola by H. Jay, one violin by Gand-Bernardel were analyzed and compared with a variety of commercial tone woods. The methods of analysis were the following: back-scattered electron imaging, X-ray fluorescence maps for individual elements, wave-length dispersive spectroscopy, energy dispersive X-ray spectroscopy and quantitative microprobe analysis. All four Cremonese instruments showed the unmistakable signs of chemical treatments in the form of chemicals which are not present in natural woods, such as BaSO4, CaF2, borate, and ZrSiO4. In addition to these, there were also changes in the common wood minerals. Statistical evaluation of 12 minerals by discriminant analysis revealed: a. a difference among all four Cremona instruments, b. the difference of the Cremonese instruments from the French and English antiques, and c. only the Cremonese instruments differed from all commercial woods. These findings may provide the answer why all attempts to recreate the Stradivarius from natural wood have failed. There are many obvious implications with regard to how the green tone wood should be treated, which chould lead to changes in the practice of violin-making. This research should inspire others to analyze more antique violins for their chemical contents.

Novel prebiotic model systems: interactions of nucleosides and nucleotides with aqueous micellar sodium dodecanoate

Abstract The partition coefficients, K-values, of adenosine, guanosine, cytidine, uridine, 51-adenylic acid (AMP), 51-guanylic acid (GMP), 51-cytidylic acid (CMP), and 51-uridylic acid (UMP) between water and aqueous sodium dodecanoate has been determined by gel filtration on Sephadex G-25. Below the critical micelle concentration of the surfactant, K-values for all nucleotides and nucleosides are similar. Differential uptake of the four nucleotides and nucleosides is observed, however, by micellar sodium dodecanoate. K-values for adenosine, AMP; guanosine, GMP; cytidine, CMP; and uridine, UMP are 6.16·103, 9.52·103; 12.0·103, 14.6·103; 19.6·103, 19.6·103, 34.2·103 and 40.3·103. Similar K-values for corresponding pairs of nucleotides and nucleosides imply that the predominant interaction is between the pyrimidine or purine rings of the substrates and the charged Stern layer of the surfactant. Prebiotic significance of these results is discussed.

Some biochemical properties of alkyl phosphotriesters of cyclic AMP

Abstract The biochemical properties of several alkyl phosphotriesters of cyclic AMP were studied with respect to their interactions with beef heart protein kinase and cyclic nucleotide phosphodiesterase. Ethyl and propyl triesters did not enhance the phosphorylation of histone by protein kinase and methyl, ethyl, propyl and butyl triesters were poor competitors for the cyclic AMP binding site of the enzyme. However, these alkyl phosphotriesters were effective inhibitors of cyclic nucleotide phosphodiesterase with the K i s arrayed in the following order: methyl > ethyl > propyl > butyl > cetyl triester. Metabolic studies with mice indicated that intraperitoneal injection of low doses of propyl triester for one week significantly increased cyclic AMP concentration.

The synthesis of 5′ thioanalogs of polydeoxyribonucleotides

Abstract Oligo 5′-thiodeoxythymidylates and oligo 5′-thiodeoxyadenylates were prepared via displacement of tosylates by thiophosphate mono- and diesters. The 5′ ends contain O-tosyl or S-phosphoryl groups, while the 3′ ends terminate in deoxythymidine. The types of starting materials used for such polymerization were 5′-O-tosyl nucleoside 3′ cyanoethyl phosphorothionates and the corresponding monoesters. Both oligonucleotide analogs possess secondary structure according to spectral evidence.

Novel prebiotic systems - Nucleotide oligomerization in surfactant entrapped water pools

SummaryOligomerization of 5′-TMP in water pools entrapped by dodecyl-ammonium chloride surfactant aggregates in benzene: hexane in the presence of dicyanodiimide at temperatures ranging from 21°–72° resulted in the formation of linear and cyclic oligonucleotides containing up to pentamers. Effects of temperature, time and surfactants have been examined. Rate constants for the formation of oligomers have been determined at five different temperatures. These data afforded values of ΔH‡ = 11.8 ± 1.9 Kcal mole−1, ΔS‡=−53α 6 e.u. and ΔG‡ = 27.4α 4.0 Kcal mole−1. Prebiotic significance of these results are discussed.