Structural comparisons of mouse histones 2A.X and 2A.Z with 2A.1 and 2A.2

The tryptic peptide patterns of the recently described H2A species H2A.X and H2A.Z from mouse were compared with the tryptic peptide patterns of the major mouse H2A's, H2A.1 and H2A.2. The identities of the H2A.1 peptides were determined by comparing their in vivo labeling with various 14C-labeled amino acids with the expected labeling determined from the known sequence. All the H2A.1 tryptic peptides larger than dipeptides were accounted for. The procedure was repeated for H2A.2, H2A.X and H2A.Z. H2A.X was found to have large regions of sequence identical to that of H2A.1 with the variability occurring mainly near the N and C termini. Mouse H2A.X had some sequence characteristics found in the sequenced H2A's of trout and sea urchin. In contrast, H2A.Z was found to have only two peptides in common with H2A.1; in addition, the labeling patterns of the non-identical peptides were too different to suggest analogous peptides. We conclude from these studies that H2A.Z differs considerably from H2A.1 in major portions of its sequence.     

Metabolism of T-2 toxin in Curtobacterium sp. strain 114-2.

The metabolic pathway of T-2 toxin in Curtobacterium sp. strain 114, one of the T-2 toxin-assimilating soil bacteria, was investigated by thin-layer and gas-liquid chromatographic analyses. T-2 toxin added to the basal medium as a single carbon and energy source was biotransformed into HT-2 toxin and an unknown metabolite. Infrared, mass spectrum, proton magnetic resonance, and other physico-chemical analyses identified this new metabolite as T-2 triol. T-2 toxin was first deacetylated by the bacterium into HT-2 toxin, and this metabolite was then biotransformed into T-2 triol without formation of neosolaniol and T-2 tetraol. No trichothecenes remained in the culture medium after prolonged culture. Some properties of T-2 toxin-hydrolyzing enzymes were observed with whole cells, the cell-free soluble fraction, and the culture filtrate. Besides T-2 toxin, trichothecenes such as diacetoxyscirpenol, neosolaniol, nivalenol, and fusarenon-X were also assimilated by this bacterium.     

2. Personality Factors in Perception

2. Personality Factors in Perception The role of personality factors is no less significant in the process of perception. From the theoretical positions of L. S. Vygotsky, A. R. Luria, and A. V. Zaporozhets it follows that the development of perception is determined by new tasks that arise during ontogenesis. Perception advances as perceptual actions develop that manifest the subject's activity (B. C. Anan'yev, 1960; Yu. B. Gippenreiter, 1958; J. Piaget, 1961; L. A. Venger, 1969; A. V. Zaporozhets, 1960; V. P. Zinchenko, 1967). The cited works show how perceptual actions develop and examine their role in constructing an image. They enumerate the developmental stages of perceptual actions and their orienting and regulating functions. The skill and operations that constitute perceptual actions, the child's perceptual development, and the methods for studying the level of perceptual development have all been researched by L. A. Venger (1969).* All of these works characteristically approach perception as an activity that includes a basic feature of the human mind, namely, its selectivity (A. N. Leont'yev).     

Aspects of audit. 2. Audit in British hospitals.

British hospitals have advantages over other areas of health care for developing and evaluating audit: more uniform and comprehensive medical records, statistical and diagnostic data, fewer patient contacts, more time to examine patients and record information. Although little has been published, a few studies show the extent to which formal audit has been developed in Britain.     

Intra-H-2 recombination in the mouse. III. I-Region characterization of haplotypes H-2at2, H-2at3 and H-2a2

Serological characterization of three K-S interval recombinant strains, TBR2 (H-2at2), TBR3 (H-2at3) and AIR 1 (H-2a2) was performed using anti-H-2, Ia, Ss and Slp antisera. The data presented here reveal that the crossover events in both TBR2 and TBR3 occurred between the I-A and I-E subregions. In both cases, the H-2K and I-A subregions were derived fron the H-2t1 of chromosome, while the I-E, S and H-2D regions were derived from the H-2b chromosome (KsAkEbSbDb). The H-2a2 chromosome resulted from a crossover event between the H-2a1 and H-2i9 chromosomes. Ia and Ss typing of AIR 1 suggested that the K to I-E regions originated from H-2a1 and the S and D regions originated from H-2i9 (KkAkEkSbDd).     

The Ca2+-induced membrane transition in mitochondria. III. Transitional Ca2+ release.

The efflux of Ca²⁺ from mitochondria respiring at steady state, and much of uncoupler-induced Ca²⁺ efflux, is shown to be a consequence of the Ca²⁺-induced membrane transition (the Ca²⁺-induced transition is the Ca²⁺-dependent sudden increase in the nonspecific permeability of the mitochondrial inner membrane which occurs spontaneously when mitochondria are incubated under a variety of conditions (D. R. Hunter, R. A. Haworth, and J. H. Southard, 1976, J. Biol. Chem.251, 5069–5077)). Ca²⁺ release from mitochondria respiring at steady state is shown to be transitional by four criteria: (1) Ca²⁺ release is inhibited by Mg²⁺, ADP, and bovine serum albumin (BSA), all inhibitors of the transition; (2) release is selective for Ca²⁺ over Sr²⁺, a selectivity also found for the transition; (3) the time course of Ca²⁺ release is identical to the time course of the change in the mitochondrial population from the aggregated to the orthodox configuration; and (4) from kinetics, Ca²⁺ release from individual mitochondria is shown to occur suddenly, following a lag period during which no release occurs. Ca²⁺ release induced by uncoupler is shown to be mostly by a transitional mechanism, as judged by four criteria: (1) release of Ca²⁺ is ruthenium red-insensitive and is an order of magnitude faster than Sr²⁺ release which is ruthenium red-sensitive; (2) release of Ca²⁺ is strongly inhibited by keeping the mitochondrial NAD⁺ reduced; (3) the kinetics of Ca²⁺ release indicates a transitional release mechanism; and (4) uncoupler addition triggers the aggregated to orthodox configurational transition which, at higher levels of Ca²⁺ uptake, occurs in the whole mitochondrial population at a rate equal to the rate of Ca²⁺ release. Na²⁺-induced Ca²⁺ release was not accompanied by a configurational change; we therefore conclude that it is not mediated by the Ca²⁺-induced transition.     

2-Amino-2-deoxygalacturonic acid in lipopolysaccharides from Pseudomonas aerugimosa.

2-Amino-2-deoxygalacturonic acid was identified as a component of the lipopolysaccharide from Pseudomonas aeruginosa N.C.T.C. 8505. The compound probably occurs in the region of polysaccharide responsible for O-antigenic specificity.     

Isolation and expression of GA 2-oxidase2 in tomato.

GA 2-oxidases, a key enzyme involves GA biosynthesis, catalyze the degradation of active C(19)-Gibberellins (GAs) through 2-hydroxylation yields inactive GA product. Searching public tomato database, the putative GA2ox2 sequences were assembled. We isolated a full-length GA2ox2 cDNA with primers designed from the assembled sequence. This gene was designed as SlGA2ox2 (GenBank accession No. EF017805). The full-length GA2ox2 gene contained a complete open reading frame (ORF) of 1203 bp, which encoded 322 amino acid residues. Amino acid sequence homology analysis of SlGA2ox2 showed an 88% identity with NtGA2ox2 in tobacco. And alignments of SlGA2ox2 with other known GA2ox from Arabidopsis, Pea, Adzuki Bean, Winter Squash etc indicate low similarity of 47-70%. Semi-quantitative RT-PCR analysis showed a specific expression profile of SlGA2ox2 in different tissues, which mainly expressed in flowers and traces were detected in roots, stems, leaves and immature fruits.