Production studies on the alkaline amylases of three alkalophilic Bacillus spp.

Summary Bacillus alcalophilus subsp. halodurans ATCC 21591, Bacillus sp. NCIB 11203 and Bacillus sp. IMD370 are obligate alkalophiles and produce alkaline -amylases with maxima for activity at pH 10.0. All three organisms yielded maximum amylase activity in a medium containing starch as a carbon source and yeatex as a nitrogen source with an initial pH 10.0.     

Polychlorobiphenyl (PCB) metabolism by plant cells

Summary Suspension cultures of Paul's Scarlet rose provided with 0.3 ppm of 2,2, 4,4-tetrachlorobiphenyl metabolized the compound at a rate of 45 proles· n^–1·g dry wt^–1. The environmental and technological significance of plants to metabolize environmentally persistent compounds is discussed.     

T cell-induced expression of membrane IgG by 70Z/3 B cells

To study T cell regulation of B cell isotype differentiation, we determined the capacity of clonal T cell populations (hybridomas derived by fusing BW5147 with Con A-activated Peyer's patch (PP) and spleen T cells) to induce "downstream" isotype expression by the pre-B cell lymphoma 70Z/3. In initial studies, we found that 70Z/3 B cells cultured in the presence of LPS (1 microgram/ml) expressed membrane IgM (mIgM) but not membrane IgG (mIgG). In contrast, 70Z/3 B cells cultured with HAJ-3 T cells, a PP-derived T cell hybridoma (as well as other similarly derived PP and spleen hybridomas), or with HAJ-3 T cells plus LPS do express mIgG. Such expression occurred in spite of mitomycin C-induced blockage of cell proliferation, and is observed in 70Z/3 B cell subclones cultured with HAJ-3 T cells. For these reasons, it is not due to selective expansion of a small pre-switched mIgG-bearing 70Z/3 B cell subpopulation. In other studies it was shown that 70Z/3 B cells expressing mIgG after induction by HAJ-3 T cells continue to express mIgM and do not secrete IgG. Finally, exposure of 70Z/3 B cells to the macrophage factor IL 1 and the T cell factors IL 2, BSF-pl, and BCGF-II present in EL-4 cell supernatants did not result in mIgG expression. On the basis of these studies, we conclude that a clonal B cell population expressing mIgM can be induced by T cells to co-express mIgG. Because the B cells do not express mIgG unless exposed to T cells, this represents a T cell-induced isotype switch.     

Induced metabolic alkalosis and its effects on 400-m racing time

Six trained male athletes who competed regularly in 400 metre races, were studied under control, alkalotic (NaHCO3) and placebo (CaCO3) conditions to study the effect of induced metabolic alkalosis on 400 m racing time. Pre and post exercise blood samples in the three conditions were analysed for pH, bicarbonate and base excess. Following ingestion of NaHCO3, pre-exercise pH, bicarbonate and base excess levels were significantly higher than either control or placebo conditions. In the alkalotic condition the subjects ran significantly (p less than 0.005) faster (1.52 s) than either the control of placebo conditions. The post-exercise pH, bicarbonate and base excess levels were all lower in the alkalotic condition than in the others. The results suggest that NaH-CO3 can be used as an effective ergogenic aid and support the speculation that the increased extracellular buffering afforded by NaHCO3 ingestion facilitated efflux of H+ from the working tissues, thus decreasing intracellular pH and hence offsetting fatigue.     

Protonation of cyclopropene complexes of platinum(0) and the reduction of cyclopropene by nitrogenases

The reactions of a series of platinum(0) cyclopropene complexes with HCl have been studied, and it is shown that the products include both ring-intact (cyclopropane-type) and ring-opened (propene-type) materials. All products are believed to be formed by hydrocarbon insertions into transient platinum-hydrogen bonds formed by addition of HCl to platinum. Mechanistic interpretation is complicated by group migrations, and double-bond shifts. Oxidative addition of a σ-cyclopropys to platinum plays a part in ring-opening reactions, whereas the cyclopropanesare believed to be produced by further hydrocarbon insertions into transient platinum-hydrogen bonds. The relevance of these models to the mechanism of reduction of cyclopropene by nitrogenases is discussed.     

Sudden and Unexpected Deaths in Infants: Histology and Virology

The histological appearance of lungs of children whose death had been sudden and unexpected has been studied in relation with the viruses found at necropsy. Fifty-one children were investigated and in 33 the lungs had the histological appearance widely accepted as characteristic of the condition previously termed “cot death.” Sixteen had the histological appearance of lymphocytic bronchiolitis, and it was from this group only that viruses were isolated. The viruses isolated were those associated with respiratory infections. Two patients showed the histological appearance of bacterial bronchopneumonia. Viruses are probably responsible for a substantial proportion of unexpected sudden deaths in infancy.