Robert W. Wheat

Ion-exchange separation and automated assay of some hexosamines: Part I

Abstract Separation of various 2-amino-2-deoxy- d -hexoses, 2-amino-2,6-dideoxy- d -hexoses, 2,6-diamino-2,6-dideoxy- d -hexoses, 3-amino-3-deoxy- d -hexoses, and 3-amino-3,6-dideoxy- d -hexoses, as well as 2-amino-2-deoxy- d -hexuronic acids and d -muramic acids, has been effected on Dowex 50 resins using pyridine-acetate buffers. The column effluents were assayed by reaction with ninhydrin in a Technicon AutoAnalyzer.

On the determination of galactosamine-uronic acid☆

Abstract A procedure for measuring galactosamine-uronic acid was developed by modifying the Levvy-McAllan (10) colorimetric procedures for free hexosamines. The modification developed included a lower tetraborate concentration and a longer alkaline heating period. A shorter N -acetylation period is required than used by Roseman and Daffner (9). With these changes, glucosamine gave twice the color yield as in the original Levvy-McAllan method. Galactosamine-uronic acid, which gave negligible color by the original procedure, yielded 50% glucosamine color in the present modification.

The occurrence of nicotinic acid mononucleotide in yeast.

Abstract A nucleotide was isolated from water-alcohol extracts of yeast by charcoal adsorption-elution and anion-exchange chromatography. The compound was identified as nicotinic acid mononucleotide.

Component enzymatic reactions of the tricarboxylic acid cycle in Escherichia coli

Abstract 1. 1. Alumina-ground Escherichia coli extracts have been found to oxidize all members of the tricarboxylic acid cycle with the exception of acetate. 2. 2. Crude extracts contain an aconitase and an isocitric dehydrogenase which convert citrate to α-ketoglutarate and CO 2 . The occurrence of these enzymes in extracts of E. coli suggests the operation of the tricarboxylic acid cycle in this organism. Other cyclic mechanisms for the oxidative removal of acetate or pyruvate are not excluded by this finding. 3. 3. Quantitative experiments with citrate as substrate reveal an additional pathway of citrate breakdown not involving isocitric dehydrogenase. 4. 4. Under conditions which favor CO 2 production from citrate, α-ketoglutarate is not attacked. On the addition of diphosphopyridine nucleotide, however, the latter disappears and CO 2 is evolved. 5. 5. Aconitase in crude extracts is inactivated by dialysis.

Serological cross-reactivity between sporothrix schenckii and various unrelated fungi

The serological cross-reactivity ofSporothrix schenckii with various unrelated fungi was investigated by use of immunodiffusion tests. A rabbit antiS. schenckii serum was obtained, which reacted withCladosporium werneckii, C. carrionii, C. bantianum, Coccidioides immitis, Phialophora jeanselmei, P. gougerotii, P. dermatitidis, Fonsecaea pedrosoi, Aspergillus fumigatus, Histoplasma capsulatum andTrichophyton mentagrophytes, but not withSaccharomyces cerevisiae antigens. The serological determinants responsible for the cross-reactions were suggested to be D-galactosyl residues.

Acid-soluble nucleotide spectrum of Neurospora crassa

Abstract Anion-exchange chromatography of wild-type Neurospora crassa nucleotides on Dowex 1 resin columns employing a concave gradient with ammonium formate buffer at pH 3 was carried out. N. crassa was found to contain cytidine diphosphocholine, diphosphopyridine nucleotide, adenylic acid, uridylic acid, uridine diphosphoacetylglucosamine, uridine diphosphoglucose, and the triphosphates of adenosine, uridine, and guanosine.

In vitro susceptibility testing of Candida isolates from clinical specimens to four antifungal agents.

A total of 231 isolates of Candida species including 163 of Candida albicans (132 of serotype A and 31 of serotype B), 42 of Candida tropicalis, 17 of Candida glabrata, 7 of Candida parapsilosis and 2 of Candida krusei were collected from clinical specimens in two medical centers, one in Japan and the other in the United States. The in vitro antifungal activities of amphotericin B, 5-fluorocytosine, miconazole and fluconazole were evaluated for the above isolates by means of a photo-read broth microdilution method for determination of the 30% inhibitory concentration (IC30). The results showed that IC30 values of fluconazole were generally great compared with those of the other drugs, regardless of Candida species. The isolates of C. albicans serotype B showed a significantly lessened susceptibility to 5-fluorocytosine compared with those of serotype A (p less than 0.01). This method has the advantage of objective measurement, thus minimizing observer variability as compared with the agar dilution test.

Isolation of Uridine Diphosphate-Glycosyl Compounds from the Slug

An examination of the acidsoluble nucleotides of Limax maximus Linn� revealed, among others, several uridine diphosphat�-glycosyl compounds. Nucleotides isolated and identified were the uridine diphosphates of glucose, acetylglucosamine, and acetylgalactosamine.

Serological cross-reactivity betweenKlebsiella pneumoniae K47 andSporothrix species

The serological cross-reactivity ofKlebsiella pneumoniae K47 antiserum with antigens of 11Sporothrix species was investigated by use of immunodiffusion. Cross-reactions occurred withK. pneumoniae K47 and theSporothrix speciesS. schenckii, S. schenckii var.luriei, S. curviconia, andS. inflata.

COMPARATIVE IMMUNOCHEMICAL STUDIES ON SPOROTHRIX SPECIES

Serological and chemical characteristics of eleven Sporothrix species were investigated by use of immunodiffusion precipitin reactions and gas liquid chromatography.