Inhibition of lipid peroxide decomposition by compounds which bind with cytochrome p-450

The kinetics of lipid peroxide decomposition catalysed by microsomal enzymes and inhibited by SKF-525 A, hexobarbital, phenobarbital and aniline were investigated. The results indicate that the in vitro interaction of hexobarbital and SKF-525 A (type I binding compounds) with microsomal cytochrome p-450 inhibits the peroxidase activity while the in vitro interaction of aniline (type II binding compound) only slightly affect the peroxidase activity. It is suggested that LAHPO and type I binding compounds are competing for the hydrophobic binding site on cytochrome p-450, while type II binding compounds such as aniline negate electron transfer non-competitively by combining with the heme.     

Fluorescence polarization as a tool to study lectin-sugar interaction

The binding ofRicinus communis agglutinin andAbrus agglutinin to 4-methylumbelliferyl β-D-galactopyranoside was studied by equilibrium dialysis, fluo-rescence quenching and fluorescence polarization. The number of binding sites and the association constant value obtained by fluorescence polarization for bothRicinus communis agglutinin andAbrus agglutinin are in close agreement with those obtained by the other methods. This indicates the potential of ligand-fluorescence polarization measurements in the investigation of lectin-sugar interactions.     

Preliminary Observations on the Pathogenesis of a Virulent Strain of Newcastle Disease Virus in Chickens

Development of Newcastle disease, after experimental and natural infection with the virulent strain VLT of Newcastle disease virus, and its growth and distribution in some selected tissues as assayed by the enumeration of plaques are reported.     

QUANTITATIVE MEASUREMENTS OF INTERACTIONS BETWEEN CROWN-GALL TUMORS AND THE PINTO BEAN HOST

Interactions between crown-gall tumors on the primary pinto bean leaf and the pinto bean seedling (Phaseolus vulgaris L. ‘Pinto‘) were estimated by quantitative measurements of tumor initiation and growth as affected by certain modifications of the host. Effects of the tumors on the host were estimated by measurements of host growth and correlation responses. The presence of crown-gall tumors was found to reduce the growth of the leaf in area but to nearly double the weight of the leaf 9 days after inoculation with Agrobacterium tumefaciens (Smith and Town.) Conn, strain B6. The presence of tumors on only one of the two primary leaves resulted in a decrease in the weight of the leaf without tumors, showing the tumors to be effective mobilization centers. Tumors also delayed the abscission of petiole explants and delayed the growth of the epicotyl bud, both reminiscent of auxin effects. The excision of the cotyledons, the epicotyl bud, or one of the pair of primary leaves at the time of inoculation increased the number of tumors initiated per leaf. Removing the epicotyl bud or one of the primary leaves, or placing a cytokinin on one of the leaves, altered leaf growth but failed to alter tumor growth, indicating that tumor growth is not affected by the changes responsible for the compensatory growth effects induced by these treatments. Tumor growth was shown to be generally correlated with leaf growth from day 2 through 8 after inoculation, suggesting that the factors normally limiting leaf growth in a determinate type leaf are also active in limiting tumor growth. The changes in the plant cell responsible for the enhanced rate of growth seen in crown-gall tumor cells, therefore, appear to occur in regulatory systems other than those normally limiting leaf growth. The regulatory systems that are affected may be identical with those activated in compensatory host growth effects.     

Influence of acetic and butyric acid addition on polysaccharide formation byClostridium acetobutylicum

Summary The production of granulose (an intracellular reserve polygranule), capsule and exopolysaccharide was investigated in a synthetic medium in which the oxido-reduction level was modified by the addition of acetic or butyric acid. After addition of the acids, granulose synthesis increased from 150 to 300 mg glucose equivalents ·1^–1 and capsular synthesis decreased by 25%. Exopolysaccharide production was unchanged under these conditions. A hypothesis that attributes a role to the polymer in the oxido-reduction sequences is discussed.     

The cytologist and bacterioses of the vaginal-ectocervical area. Clues, commas and confusion

To evaluate the role of the cytologist in the diagnosis of bacterial vaginosis, the predominant bacterial patterns seen in 157 Papanicolaou-stained cervical smears were assessed and classified as large bacillus, anaerobic or scanty. A large bacillus pattern was found in 73 smears (46%), an anaerobic pattern in 77 (49%) and scanty bacteria in 7 (5%). Comma-shaped (curved) bacilli were found in 34 smears. The prevalence of clue cells in smears with anaerobic patterns was 73%. Gardnerella vaginalis was cultured from 89% of the cases with anaerobic-type smears containing clue cells and from 88% of those with anaerobic-type smears lacking clue cells. Mobiluncus sp. was cultured from 83% of the cases with anaerobic-type smears showing curved bacilli and 14% of those with anaerobic-type smears lacking curved bacilli. Papanicolaou-stained smears were found to be more sensitive and more specific for identifying clue cells than were wet preparations. A positive association was found between a positive KOH "whiff" test and the presence of curved bacilli on the Papanicolaou-stained smear. The clinical significance of these findings is discussed.     

The human cystatin C gene (CST3), mutated in hereditary cystatin C amyloid angiopathy,is located on chromosome 20

Summary Hereditary cystatin C amyloid angiopathy has recently been shown to be caused by a point mutation in the cystatin C gene. To determine the chromosomal localization of the gene, 20 human-rodent somatic cell hybrids and a fulllength cystatin C cDNA probe were used. Southern blot analysis of BamHI digested cell hybrid DNA revealed that the probe recognizes a 10.6 kb human specific fragment and that this fragment cosegregates with human chromosome 20. Therefore, the human cystatin C gene (CST3) was assigned to chromosome 20.