Timing of single daily meal influences relations among human circadian rhythms in urinary cyclic AMP and hemic glucagon, insulin and iron.

Relations among circadian rhythms in serum iron, glucagon and insulin and urinary cyclic AMP excretion differ drastically when diurnally active, nocturnally resting human adults consume all daily food for one week as breakfast only and for another week as dinner only - a finding of interest to diverse fields, e.g., for optimizing certain kinds of therapy or for a better utilization of calories.     

Mimicking the alloantigenicity of proteins with chemically synthesized peptides differing in single amino acids

Recent studies have shown that short chemically synthesized peptides very often induce antibodies which react with the cognate sequence in the intact folded protein. Since such antibodies react with known regions of proteins, they are of predetermined specificity and offer a precision not previously possible with immunological probes. A basic concept emerging from the use of such antibodies in viral systems is that the differential immunogenicity of closely related proteins can be mimicked by short peptides which span the regions of sequence variation. To generalize this concept, we have studied the two Thy-1 proteins which vary by only a single amino acid. Chemically synthesized peptides differing in only one out of 19 amino acids were able to induce allospecific antisera. Thus, single amino acid changes have similar effects on the immunogenicity of proteins and small peptides, even though the latter are free from constraints provided by neighbouring structures in the tertiary configuration of the intact folded proteins.     

HRPT2, encoding parafibromin,is mutated in hyperparathyroidism-jaw tumor syndrome

We report here the identification of a gene associated with the hyperparathyroidism-jaw tumor (HPT-JT) syndrome. A single locus associated with HPT-JT (HRPT2) was previously mapped to chromosomal region 1q25-q32. We refined this region to a critical interval of 12 cM by genotyping in 26 affected kindreds. Using a positional candidate approach, we identified thirteen different heterozygous, germline, inactivating mutations in a single gene in fourteen families with HPT-JT. The proposed role of HRPT2 as a tumor suppressor was supported by mutation screening in 48 parathyroid adenomas with cystic features, which identified three somatic inactivating mutations, all located in exon 1. None of these mutations were detected in normal controls, and all were predicted to cause deficient or impaired protein function. HRPT2 is a ubiquitously expressed, evolutionarily conserved gene encoding a predicted protein of 531 amino acids, for which we propose the name parafibromin. Our findings suggest that HRPT2 is a tumor-suppressor gene, the inactivation of which is directly involved in predisposition to HPT-JT and in development of some sporadic parathyroid tumors.     

Structural basis of actin filament nucleation and processive capping by a formin homology 2 domain

The conserved formin homology 2 (FH2) domain nucleates actin filaments and remains bound to the barbed end of the growing filament. Here we report the crystal structure of the yeast Bni1p FH2 domain in complex with tetramethylrhodamine-actin. Each of the two structural units in the FH2 dimer binds two actins in an orientation similar to that in an actin filament, suggesting that this structure could function as a filament nucleus. Biochemical properties of heterodimeric FH2 mutants suggest that the wild-type protein equilibrates between two bound states at the barbed end: one permitting monomer binding and the other permitting monomer dissociation. Interconversion between these states allows processive barbed-end polymerization and depolymerization in the presence of bound FH2 domain. Kinetic and/or thermodynamic differences in the conformational and binding equilibria can explain the variable activity of different FH2 domains as well as the effects of the actin-binding protein profilin on FH2 function.     

材料物理与化学重点学科建设的思考

教学型大学的主要任务是提高教学质量,培养应用型高级专门人才.学科建设是人才培养的关键.重点学科建设应结合学科特点和优势,明确学科研究方向,紧密结合教学,突出应用性教育的特点,发挥重点学科的科学研究、人才培养、为社会服务三大职能.就材料物理与化学学科建设提出了自己的初步思考.     

Transfer of diabetes in mice prevented by blockade of adhesion-promoting receptor on macrophages

Insulin-dependent diabetes mellitus (IDDM) is a disease with an autoimmune aetiology. The non-obese diabetic mouse is a good spontaneous animal model of the human disease, with IDDM developing in 50-80% of female mice by the age of 6 months. The disease can be transferred by splenic T cells from diabetic donors and is prevented by T-cell depletion. The mechanism(s) by which the beta cell is specifically destroyed is not known, but T cells and macrophages have both been implicated, based on the presence of macrophages in the infiltrated islet and the ability of chronic silica treatment to prevent disease. The monoclonal antibody 5C6 is specific for the myelomonocytic adhesion-promoting type-3 complement receptor (CR3 or CD11b/CD18) and does not bind to T cells. Here we show that blockade of macrophage CR3 in vivo prevents intra-islet infiltration by both macrophages and T cells and inhibits development of IDDM. We conclude that both T cells and macrophages have an essential role in the onset of IDDM.     

1,8-萘啶氮氧化物与3d元素高氯酸盐配合物研究

在非水介质中合成出1,8-萘啶氮氧化物与6个3d元素(锰,铁,钴,镍,铜,锌)高氯酸盐的固体配合物.对配合物进行了熔点及溶解性测定.通过元素分析、红外光谱、紫外光谱和摩尔电导等测定.研究了配合物的组成和性质.