Characterization of the iron-sulfur protein of the mitochondrial outer membrane partially purified from beef kidney cortex

The iron-sulfur protein present in the mitochondrial outer membrane has been partially purified from beef kidney cortex mitochondria by means of selective solubilization followed by DEAE-cellulose chromatography. The EPR spectrum of the iron-sulfur protein with g-values at 2.01, 1.94 and 1.89 was well resolved up to 200 K which is unusual for an iron-sulfur protein. Analyses confirmed a center with two iron and two labile sulfur atoms in the protein. By measuring the effect of oxidation-reduction potential on the EPR signal amplitude, midpoint potentials at pH 7.2 were determined both for the purified iron-sulfur protein, +75 (+/- 5) mV, and in prepared mitochondrial outer membrane, +62 (+/- 6) mV. At pH 8.2 slightly lower values were indicated, +62 and 52 mV, respectively. The oxidation-reduction equilibrium involved a one electron transfer. A functional relationship to the rotenone-insensitive NADH-cytochrome c oxidoreductase in the mitochondrial outer membrane is suggested. Both this activity and the iron-sulfur center were sensitive to acidities slightly below pH 7 in contrast to the iron-sulfur centers of the inner membrane.

Immunopathologic studies of rheumatoid arthritis. I. Absence of complement-dependent cytotoxicity of rheumatoid sera for rheumatoid synovial cell cultures

A sensitive complement-dependent chromium release cytotoxicity assay was used to determine whether sera from rheumatoid arthritis (RA) patients contain antibody specific for an antigen on rheumatoid synovial cell cultures. Two hundred eight RA sera-RA synovial culture combinations were studied employing 21 sera and 16 synovial membranes; control combinations were derived from 5 normal sera and 10 degenerative joint disease synovial membranes. Anticomplementary activity of some rheumatoid sera was overcome using an increased complement concentration. The percent cytotoxicity of RA serum-RA culture combinations, both homologous and autologous, was not significantly greater than that of RA serum-control culture combinations. No correlation between duration of disease or duration of cell culture and percent cytotoxicity was found. Thus a unique antigen on cultured rheumatoid synovial cells was not recognized by rheumatoid serum antibody by use of this cytotoxicity assay.

Large-sized polysomes in Chironomus tentans salivary glands and their relation to Balbiani ring 75S RNA

Polysomes from the salivary glands of Chironomus tentans were investigated to determine whether Balbiani ring 75S RNA is incorporated into polysomal structures, and thus probably acts as messenger RNA. A new extraction technique for obtaining ribonucleoproteins was applied that gives a high yield of polysomes with only moderate degradation of the cytoplasmic, high molecular weight RNA. The polysomes sedimented in a broad region (200-2,000S) with a peak value of about 700S, which suggested that they were partly of very large sizes. This was confirmed by visualization of the polysomes in the electron microscope: 400S polysomes contained mainly 11-16 ribosomes, and 1,500S polysomes about 60 ribosomes per polysome. However, polysomes containing 100 or more ribosomes were also observed. It was further established that most of the cytoplasmic 75S RNA was located in polysomes, preferentially in the most rapidly sedimenting ones. From the available information on Balbiani ring RNA in cytoplasm and the present demonstration of 75S RNA molecules in polysomes, it was concluded that at least some Balbiani ring RNA, generated as 75S RNA within the Balbiani rings, eventually enters polysomes without being measurably changed in size. The present information on the potential amino acid coding sequences in 75S RNA is discussed in relation to the large size of the polysomes observed.

Search for epizootic-like Venezuelan encephalitis virus at enzootic habitats in Guatemala during 1969-1971

Seventy-four strains of Venezuelan encephalitis (VE) virus recovered from sentinel hamsters or mosquitoes at enzootic habitats in Guatemala in the two years following the 1969 epidemic-equine epizootic were examined for ability to produce small plaques in Vero African green monkey kidney cell cultures, like isolates obtained during the epizootic. (a) One strain recovered from a sentinel hamster in late October 1969 at an enzootic habitat near the epicenter of the hemagglutination-inhibition (HI) and equine-virulence properties like epizootic virus; this strain retained its small plaque characteristic after inoculation and recovery from bloods of three horses. (b) None of the other 73 strains produced uniformly small plaques, but 31 formed a few small plaques among large ones. Virions from small plaques of five strains were cloned twice in Vero cell cultures. Four clones produced uniformly small plaques after one more passage in Vero cells; three had hemagglutination-pH properties compatible with epizootic virus or intermediate between epizootic and enzootic virus, but HI tests with these three hemagglutinins or with antibody to the fourth cloned strain showed them to be like Central American enzootic virus. One of three cloned strains tested in horses produced encephalitis and death in one of four horses; another strain produced encephalitis with recovery in one of two horses. (c) Thus these small Vero plaque clones resembled Central American enzootic strains of VE virus in HI and equine-virulence tests, and the small Vero plaque characteristic was not a satisfactory marker for consistently isolating equine-virulent, epizootic VE virions. Nevertheless, this technic led to recognition of one epizootic strain isolated at an enzootic habitat in Guatemala at the end of 1969 outbreak. Whether this strain was there before the outbreak or subsequently penetrated the habitat is uncertain. During the next two years, this strain did not become dominant in that enzootic focus.

Physiological and DNA characterization of Candida maltosa, a hydrocarbon-utilizing yeast

Selected yeast classified as Candida sake van Uden et Buckley were examined for their physiological, morphological and immunological properties and their DNA relatedness. Candida maltosa Komagata, Nakase et Katsuya is herein recognized as a species separate from C. sake, Candida maltosa was distinguished from C. sake and from C. tropicalis by insignificant DNA reassociation. In addition, C. maltosa was distinguished from C. sake by its higher maximal growth temperature and lower guanine plus cytosine content of its DNA and from C. tropicalis by its failure to utilize soluble starch for growth and its resistance to cycloheximide. The species C. cloacae and C. subtropicalis are placed in synonymy with C. maltosa.

A double blind controlled trial of a new anorectic agent AN448

AN448 is a new anorectic agent, which in the dose used, is without the CNS stimulant properties of the amphetamines. Patients entering the trial were a highly resistant group at least 20 percent above ideal weight chosen from an ischaemic-hyperlipidaemic clinic population. In a double blind trial of 12 patients on the active drug and nine patients on placebo, a highly significant weight loss occurred over 12 weeks in the active group only. A significant reduction in serum cholesterol occurred independently of weight loss but there was no reduction in the serum triglycerides and no change in the lipoprotein electrophoretic pattern. The drug is shown to be effective for this group of patients and may also be useful as a cholesterol lowering agent.

Antigenic and biologic characteristics of Venezuelan encephalitis virus strains including a possible new subtype, isolated from the Amazon region of Peru in 1971

Nine strains of Venezuelan encephalitis (VE) virus isolated from the Amazon region of Peru in 1971 were identified as antigenic subtype I based on plaque-reduction neutralization tests with four and 20 units of antibody. A tenth strain, 71D1252, was possibly a new subtype, but was related to subtypes I and III. Hemagglutinins of each strain made from infected mouse brains had optimals pHs of 6.2 and 6.4. Nine strains were pathogenic for adult hamsters and adult mice, but strain 71D1252 inapparently infected some adult hamsters and mice inoculated peripherally. Plaques of nine strains in Vero African green monkey kidney cell cultures were intermediate in size between representative epizootic and enzootic strains, but plaques of strain 71D1252 were small like epizootic strains.

Portable anaesthetic machine

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Lunar Crust: Structure and Composition

Lunar seismic data from artificial impacts recorded at three Apollo seismometers are interpreted to determine the structure of the moon's interior to a depth of about 100 kilomneters. In the Fra Mauro region of Oceanus Procellarum, the moon has a layered crust 65 kilometers thick. The seismic velocities in the upper 25 kilometers are consistent with those in lunar basalts. Between 25 and 65 kilometers, the nearly constant velocity (6.8 kilometers per second) corresponds to velocities in gabbroic and anorthositic rocks. The apparent velocity is high (about 9 kilometers per second) in the lunar mantle immediately below the crust.

A simple method for studying nuclear division in free-living soil amoebae

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