Aerocavin, a new antibiotic produced by Chromobacterium violaceum

A new antibiotic, aerocavin, has been isolated from fermentation broths of a non-pigmented strain of Chromobacterium violaceum. The structure 1 was deduced from its spectroscopic properties and X-ray diffraction analysis. Aerocavin exhibits activity in vitro against Gram-positive and Gram-negative bacteria.

Xylocandin: a new complex of antifungal peptides. I. Taxonomy, isolation and biological activity

Xylocandin is a complex of novel peptides with potent antifungal activity that is produced by Pseudomonas cepacia ATCC 39277. The complex was isolated from the fermentation broth by extraction with butanol-methanol, 9:1, followed by collection of the precipitate formed upon concentration of the solvent extract. Purification was effected by chromatography on reversed phase and size exclusion gels followed by TLC on silica gel. These techniques afforded eight components: A1, A2, B1, B2, C1, C2, D1 and D2. A mixture of the two closely related components, xylocandins A1 and A2, displayed potent anticandidal and antidermatophytic activities in vitro. The activity was diminished by the presence of serum or vaginal washings. No antibacterial activity was demonstrable.

Exposure of firefighters to diesel emissions in fire stations

Personal sampling techniques were used to evaluate firefighter exposure to particulates from diesel engine emissions. Selected fire stations in New York, Boston and Los Angeles were studied. Firefighter exposure to total particulates increased with the number of runs conducted during an 8-hr period. In New York and Boston where the response level ranged from 7 to 15 runs during an 8-hr shift, the resulting exposure levels of total airborne particulates from diesel exhaust were 170 to 480 micrograms/m3 (TWA). Methylene chloride extracts of the diesel particulates averaged 24% of the total. The authors' findings suggest that additional research is necessary to assess fire station concentrations of vehicle diesel exhaust that may have adverse health consequences to firefighters.

Effect of aerosol size on the blood lead distribution of industrial workers

The size distribution measurements of lead aerosol from a brass foundry and primary lead smelter are used to simulate blood lead distributions applying a pharmacokinetic model developed by Bernard. The predicted distribution of blood lead levels determined using the actual size distribution of lead aerosol are compared to the blood lead levels predicted according to the model assumptions adopted in setting the OSHA lead standard. In the furnace area of the smelter and the pouring area of the foundry the predicted mean blood lead level is higher than that found in the standard whereas, in the smelter's sintering and mixing operation the blood lead level is less than that suggested by the standard. The data support the conclusion that size-selective sampling needs to be considered for incorporation into the OSHA lead standard.

Particle bounce in a personal cascade impactor: a field evaluation

The collection characteristics of five types of substrates (collection surfaces) used in personal cascade impactors were evaluated for particle bounce in the laboratory with lead dioxide dust, and in the field with brass pouring fume and brass grinding dust. The substrates tested were uncoated stainless steel, silicon grease-coated stainless steel, oil-saturated Millipore membrane filter, oil-saturated Teflon membrane filter and oil-saturated sintered stainless steel. The use of coated and uncoated stainless steel plates to collect lead dioxide dust produced no difference in measured mass median diameter (MMD); however, with brass grinding dust, there was a 50% decrease in measured MMD when uncoated stainless steel substrates were used, as compared with coated stainless steel substrates. Oil-saturated Millipore membrane surfaces gave consistently lower MMDs than coated stainless steel surfaces. Coated and uncoated stainless steel gave similar MMDs when used to sample brass pouring fume. Oil-saturated Teflon membrane and oil-saturated sintered metal, surfaces for which the collection efficiency is presumed to be independent of the particle loading, gave MMDs similar to those measured for grease-coated stainless steel. The implications of these comparisons are discussed. It is concluded that bounce characteristics are strongly dependent on aerosol material and the suitability of collection surfaces needs to be determined by field evaluation.

In vivo and in vitro release of cyanide from neurotoxic aminonitriles

Cyanide release from neurotoxic aminonitriles was measured following in vitro incubation with both microsomes and liver slices. Investigation of cyanide released as urinary thiocyanate following ip aminonitrile administration to rats was also measured. The yield of cyanide in the in vivo study, as measured by the mole percent of administered dose, was greatest from dimethylaminonitrile (DMAA), followed by trimethylaminopropionitrile (TMAPN), dimethylaminopropionitrile (DMAPN), 3,3'-iminodipropionitrile (IDPN), dimethylaminobutyronitrile (DMABN), and monomethylaminopropionitrile (MMAPN). Urinary excretion of thiocyanate accounted for 48.9% of the administered DMAA, 11.6% of TMAPN, 8.0% of DMAPN, 6.8% of IDPN, 3.1% of DMABN, and 1.8% of MMAPN. Incubation of aminonitriles and related compounds with microsomes or liver slices from rats yielded measurable quantities of cyanide from all the compounds tested except for DMABN, TMABN, and succiononitrile. Quantitative evaluation of the yield of formaldehyde by demethylation following microsomal incubation was also determined. The signs of acute toxicity in rats after ip administration of KCN were similar only to those in rats administered DMAA.

Phenacein--an angiotensin-converting enzyme inhibitor produced by a streptomycete. II. Isolation, structure determination and synthesis

Phenacein, an inhibitor of angiotensin-converting enzyme, has been isolated from the fermentation broth of a Streptomyces species belonging to the Streptomyces tanashiensis-zaomyceticus group. The inhibitor was shown to be 3,6-dihydroxy-1-phenazinecarboxylic acid by spectroscopic, degradative and synthetic methods.

Automated synthesis of gene fragments

The DNA/RNA Synthesizer provides a complete and automated procedure for the synthesis of DNA sequences. Each base unit is added in a 30-minute cycle, permitting a tetradecamer to be constructed in 6 1/2 hours. The complete procedure is described, including a practical procedure for isolation and purification of the desired DNA sequence.

Siderochelin, a new ferrous-ion chelating agent produced by Nocardia

A new ferrous-ion chelating agent, siderochelin, was isolated from fermentation broths of Nocardia sp. SC 11,340. Siderochelin was produced by conventional submerged culture and purified by solvent extraction and recrystallization. The antibiotic was crystallized from acetonitrile as a mixture of diastereoisomers. The molecular formula of siderochelin was determined as C11H13N3O3 on the basis of elemental analysis and mass spectrometry, and the structure was elucidated by X-ray crystallography. The compound shows a broad spectrum of antimicrobial activity, being active against bacteria, fungi and protozoa.

Tissue and species-specific effects of small molecular weight nuclear RNA's on transcription in isolated mammalian nuclei

Small molecular weight nuclear RNA's (SnRNA's) purified from the 0.35 M NaCl extract of chromatin from human and monkey tissues have been found to stimulate transcription of chromatin in isolated nuclei in a tissue- and species-specific manner. While SnRNA from normal human cells (WI38 fibroblasts and placenta) stimulates homologous transcription to some extent, it has a greater activity on transcription of heterologous tissue of the same species and no activity on heterologous tissue of a different species (monkey kidney cells). Likewise SnRNA from monkey cells stimulates transcription of homologous chromatin but has no effect on human cells. Fractionation of the RNA's in polyacrylamide gradient slab gels revealed that in all cases the active RNA was 160-175 nucleotides in length. Our results are compatible with the hypothesis that the active RNA's are involved in the determination and maintenance of tissue differentiation by recognizing promoter or regulator sequences in the DNA and act at the level of the nucleosome to induce tissue-specific genes.

Separation and biologic activities of individual components of S15-1, a streptothricin class antibiotic

A method is described for isolation of gram quantities of the components of the streptothricin complex S15-1 utilizing CM Sephadex column chromatography eluted with 10% acetic acid as an eluant followed by gradient elution with 10% acetic acid containing 0.02 N approximately 0.03 N HCI. Streptothricins F and E, as well as an unidentified component C1, have been isolated and their comparative biological activities determined. Streptothricins F and E were comparable in taeniacidal activity in mice infected with Hymenolepis nana ia feeding either one at 0.05% in the diet removed 92 approximately 100% of the adult tapeworms. The unidentified component C1 was inactive at the levels tested. In contrast, component C1 was the most active in antimicrobial activity against Bacillus subtilis and in inhibiting the urease activity of proteus mirabilis. In the former test, the ratios of activity were; 1:7:30 for F:E:C1 and in the latter; 1:2:4 for F:E:C1.

Izumenolide-a novel beta-lactamase inhibitor produced by Micromonospora. I. Detection, isolation and characterization

Micromonospora chalcea subsp. izumensis produces a novel beta-lactamase inhibitor izumenolide (EM4615). Isolation of izumenolide was performed by extraction into butanol under acidic conditions and then back extraction into water at neutrality. The compound was precipitated from the aqueous phase by the addition of calcium or barium salts. Further purification was achieved by distribution in BuOH - 1 N NaOH. Izumenolide is a macrolide containing sulfate ester groups.

Stimulation of transcription of chromatin by specific small nuclear RNAs

Small molecular weight nuclear RNAs (SnRNA) purified from the chromatin of SV40-transformed W138 human fibroblasts have been found to stimulate transcription of chromatin in homologous isolated nuclei as well as in nuclei of untransformed human and monkey cells. Stimulation in normal cell nuclei involves an increase in both initiation sites and rate of elongation of RNA chains. Fractionation of the SnRNA in polyacrylamide gradient slab gels revealed that the "active" RNA was 160-175 nucleotides in length.

Ionomycin, a new polyether antibiotic

Ionomycin, a new polyether antibiotic with a high affinity for calcium ions, is obtained in pure form from fermentation broths of Streptomyces conglobatus sp. nov. Trejo by solvent extraction. It is unique amongst known polyether antibiotics in that it has a UV absorption maximum at 300 nm. thereby distinguishing it from other antibiotics of its class. The Ca salt has the molecular formula C41H70O9Ca. Ionomycin is a narrow spectrum antibiotic being active against Gram-positive bacteria.

Indicine-N-oxide: the antitumor principle of Heliotropium indicum

Extracts of Heliotropium indicum Linn. (Boraginaceae) showed significant activity in several experimental tumor systems. The active principle is isolated and shown to be the N-oxide of the alkaloid, indicine, previously isolated from this plant. Supporting structural data and anti-tumor data are provided.

Isolation of Abscisin, an Abscission Accelerating Substance

A crystalline substance, designated abscisin, which accelerates abscission of excised debladed petioles at 10(-2) microgram per abscission zone, has been isolated from cotton burs. The yield was approximately 1 milligram from 10 kilograms of dry plant material.