Analysis for carbamate insecticides and metabolites.
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Of the more conventional pesticidal chemicals, the carbamate insecticides pose some unique problems relative to residue analysis. Most of these compounds are unstable under conditions normally used for GLC analysis and require special attention if this technique is to apply to the carbamates. Moreover, the carbamates are commonly metabolized to products which are toxicologically significant and which must be included in any analytical considerations. These and other problems inherent in carbamate residue methodology are discussed in this report along with technique currently utilized or having potential as sound procedures for the analyses of carbamate insecticides. (+info)
The preparation of 5-cyanouracil and 5-cyano-2'-deoxyuridine from the corresponding 5-iodo derivative and cuprous cyanide.
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5-Cyanouracil has been prepared in high yield from cuprous cyanide and 5-iodouracil. The deoxynucleoside has been similarly prepared form 5-iodo-2'-deoxyuridine and this has enabled these compounds to be labelled with (14-C) cyanide. Attempts have been made to incorporate 5-cyanouracil into Escherichia coli 15T and into Mycoplasma mycoides var. capri DNA under conditions in which several other 5-substituted uracils have been incorporated, but without success. Similarly 5-cyano-2'-deoxyuridine could not be incorporated into the DNA of T3 phage under conditions in which 5-bromo-2'-deoxyuridine is easily incorporated. These results suggest that the criteria for a 5-substituted uracil to be incorporated into DNA in vivo depends on some factor other than the size of the substituent. (+info)
Inhibition of microbial growth by fatty amine catalysts from polyurethane foam test tube plugs.
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When polyurethane foam test tube plugs are autoclaved, they release volatile fatty amines that inhibit the growth of some microorganisms. The chemical structures of these amines were determined by the use of a gas chromatograph-mass spectrometer. They are catalysts used to produce the foam. The problem of contaminating growth media with toxic substances released from polymeric materials is discussed. (+info)
Antibiotic A-16316-C, a new water-soluble basic antibiotic.
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A new water-soluble basic antibiotic named antibiotic A-16316-C was isolated together with antibiotic A-396-I and hygromycin B from a streptomyces strain identified as Streptoverticullium eurocidicus. The properties of the antibiotic A-16316-C were similar to those of destomycin B. But it was found that the antibiotic A-16316-C was not identical with destomycin B on the basis of NMR analysis. On acidic degradation antibiotic A-16136-C gave N, N'-dimethyl-2-deoxystreptamine, destomic acid and D-mannose. The gross structure for antibiotic A-16136-C was deduced from chemical reactions and spectral data. (+info)
A glyoxalase I inhibitor of a new structural type produced by Streptomyces.
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Many streptomyces strains produced an inhibitor of crude glyoxalase prepared from rat liver which did not inhibit glyoxalase I prepared from yeast. Another inhibitor, C11H14O6, which inhibited glyoxalases prepared from both rat liver and yeast was obtained from a cultured broth of Streptomyces griseosproeus and crystallized. Preincubation of this inhibitor with reuduced glutathione increased its inhibitory activity, which suggested its reaction with reduced glutathione. It showed a strong inhibition of growth of HeLa cells and inhibition of Ehrlich ascites carcinoma by daily injection. It also showed weak inhibition of the solid type of Ehrlich carcinoma and prolonged the survival period of mice inoculated with L-1210 cells. (+info)
The instilled fluid dynamics and surface chemistry of polymers in the preocular tear film.
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Using slit lamp fluorophotometry it was demonstrated that the rate of drainage of a vehicle placed in the eye increased with increasing volume and that polymer solutions increased the thickness of the precorneal tear film (PTF). By increasing the viscosity of the delivery vehicle, (e.g., a hydroxypropylmethylcellulose polymer solutions), the PTF retention of fluorescein could be increased. The increased retention was shown to be due to an increase in the tear reservoir volume provided by the more viscous solutions. The PTF retention of fluorescein in a polyvinyl alcohol (PVA) vehicle was not as viscosity dependent, although PVA did seem to produce greater initial PTF fluorescence. This suggested that PVA initially produced a thicker PTF. The PTF retention of fluorescein by five commercial solutions did not have any relation to their wetting properties. The only good correlation with fluorescein retention in the PTF measured, seemed to be the ability of different polymer solutions to stabilize a thick layer of water as measured by the spontaneous spreading of polymer molecules at the air/liquid interface on wet glass surfaces. This model was designed to simulate tear film spreading in vivo. The results suggest that different polymer solutions may produce thicker PTF's than normal by virtue of their ability to drag water with them as they spread over the ocular surface with each blink. Mechanisms by which polymer solutions may increase the thickness of the PTF are discussed. (+info)
Bacteriophage T3 induces an enzyme activity which hydrolyzes S-adenosylmethionine. This S-adenosylmethionine hydrolase is interesting, not only because of its unique activity, but also because the protein has to overcome host restriction [F. W. Studier and N. R. Movva (1976) J. Virol. 19, 136-145]. S-Adenosylmethionine hydrolase was purified to homogeneity using affinity chromatography on S-adenosylhomocysteine-Sepharose. The enzyme occurs in two forms, A and B. Form A consists of the viral peptide chain only; its native and subunit molecular weight is 17,000. Form B contains, in addition, a host subunit with a molecular weight of 49,000. The host subunit does not modify S-adenosylmethionine cleavage in vitro and no apparent relationship to the host-restriction system could be detected. (+info)
Isolation and structure elucidation of a novel griseorhodin.
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Three antibiotics possessing cytotoxic properties were isolated from a strain of Streptomyces griseus (FCRC-57). One was found to be identical with griseorhodin A. A second, FCRC-57-U, was found to be identical to griseorhodin C. FCRC-57-G is a new antibiotic structurally related to griseorhodins A and C, and is active against KB cells in vitro. The structure of this new antibiotic was determined using mass spectrometry, proton and carbon nuclear magnetic resonance spectroscopy and synthesis. (+info)