The structure and evolution of the spider monkey delta-globin gene

We have isolated the delta-globin gene of the New-World spider monkey, Ateles geoffroyi, and compared its nucleotide sequence with those of other primate delta- and beta-globin genes. Among primate delta-globin genes, the rate of nonsynonymous substitutions is much less than the rate of synonymous substitutions. This suggests that primate delta- globin genes may remain under evolutionary conservation, perhaps because hemoglobin A2 has an as yet unknown physiological importance.      

Decarboxylation-dependent transamination catalyzed by mammalian 3,4-dihydroxyphenylalanine decarboxylase

In addition to the usual decarboxylation, pig kidney 3,4-dihydroxyphenylalanine (dopa) decarboxylase catalyzes a decarboxylation-dependent transamination which converts dopa into 3,4-dihydroxyphenylacetaldehyde and sinultaneously converts enzyme-bound pyridoxal-P into pyridoxamine-P. Similar reactions occur when this enzyme acts on m-tyrosine, alpha-methyldopa, and alpha-methyl-m-tyrosine. The transamination occurs in about 0.02% of decarboxylations of dopa and m-tyrosine and in about 2% of decarboxylations of alpha-methyldopa and alpha-methyl-m-tyrosine. The fraction of decarboxylations proceeding by the transamination pathway is independent of pH. This reaction appears to result from a divergence in the normal mechanism of decarboxylation; the quinoid intermediate which is formed by decarboxylation of the substrate-pyridoxal-P-Schiff base ordinarily protonates on the alpha carbon of the amino acid, but protonation occasionally occurs at the benzylic carbon of the coenzyme, and this latter route leads to transamination.     

Using dynamic pupillometry as a simple screening tool to detect autonomic neuropathy in patients with diabetes: a pilot study

Background  

Autonomic neuropathy is a common and serious complication of diabetes. Early detection is essential to enable appropriate interventional therapy and management. Dynamic pupillometry has been proposed as a simpler and more sensitive tool to detect subclinical autonomic dysfunction. The aim of this study was to investigate pupil responsiveness in diabetic subjects with and without cardiovascular autonomic neuropathy (CAN) using dynamic pupillometry in two sets of experiments.     

一种新的肝细胞生成素（HPO）转录本及其生物学活性

利用 5′RACE技术从人胎肝组织中分离一种新形式的肝细胞生成素 (HPO 2 0 5 )cDNA ,其编码蛋白质氨基酸序列的N端较已报道的人肝细胞生成素HPO(hepatopoietin)多 80个氨基酸 ,推测其蛋白质分子量为 2 3kD。RT PCR检测HPOmRNA在多种肝癌细胞中表达 ,Western印迹可检测到 2 3kDHPO 2 0 5表达 ,表明此种形式HPO在自然状态下存在。将构建的HPO 2 0 5真核表达载体转染入COS 7细胞 ,其表达蛋白质能够刺激HepG2肝癌细胞DNA合成 ;将HPO 2 0 5、HPO和荷空表达载体分别转染入低水平表达HPO的Bel 740 2肝癌细胞株 ,发现HPO 2 0 5比HPO具有较强的激活MAPK磷酸化的活性。细胞周期分析稳定转染HPO 2 0 5 ,HPO细胞的增殖周期也支持这一结论。这些结果表明HPO 2 0 5具有刺激肝源性细胞增殖的活性 ,并提示HPO 2 0 5可能较HPO有更强的生物学活性     

Acquired cellular resistance following transfer of lymphocytes from mice infected repeatedly with Staphylococcus aureus

Cell-mediated immunity following multiple staphylococcal infections of mice was found to differ from other established experimental models of infection with facultative intracellular microorganisms in that acquired cellular resistance was of extremely short duration. This is perhaps a reflection of the fact that Staphylococcus aureus does not multiply or survive within mononuclear phagocytes and are eliminated from the tissues within a few days. Thus, a sustained antigenic stimulus required for maintenance of cellular immunity does not occur. Spleen cells from immunized mice transferred simultaneously with staphylococcal antigen conferred resistance against Listeria monocytogenes on unimmunized syngeneic mice. Treatment of immune splenic lymphocytes with antilymphocyte serum and complement markedly inhibited or abolished capacity of the lymphocytes to transfer resistance to Listeria. These results support and extend our previous data which suggest that mice infected repeatedly with staphylococci are able to suppress the growth of L. monocytogenes via cellular rather than humoral mechanisms.     

含锰固氮酶组分Ⅰ蛋白的纯化和特性

棕色固氮菌（Azotobacter vinelandii Lipmann)突变种UW3能在无Mo的无氨培养基中固氮生长,低浓度的Mn对UW3突变种生长有促进作用,从在Mn中生长的UW3菌体中分离得到的部分纯固氮酶组分Ⅰ蛋白含量有Mn和Fe原子（Fe/Mo/Mn为10．41：0．19：1．00）并有OP MoFe蛋白一半的还原乙炔和质子的活性。这种蛋白的吸收光谱和圆二色谱与MoFe蛋白存在明显的差异,含Mn蛋白的亚基分子量都与MoFe蛋白的α亚基相近。初步结果表明,这种含Mn蛋白可胡是一种固氮酶组分Ⅰ蛋白。     

固氮酶铬铁蛋白的晶体生长

在合适的结晶条件下 ,从含Cr无氨培养基中生长的固氮菌 (AzotobactervinelandiiLipmann)突变种UW3 中纯化出的CrFe蛋白可从溶液中析出深棕色斜四棱柱晶体 ,晶体最大的两条对角线长度分别可达 0 .2 5mm和 0 .12mm。PEG 80 0 0、MgCl2 、NaCl、Tris和Hepes缓冲液的浓度及结晶方法等对该蛋白的出晶率、晶核数目、晶体大小和质量都有明显影响。CrFe蛋白结晶所需的上述化合物的最适浓度与在Mn中生长的固氮菌突变种UW3 的MnFe蛋白和缺失nifZ固氮菌突变种的ΔnifZMoFe蛋白结晶所需的最适浓度有所不同。结果表明 ,该蛋白晶体可能为CrFe蛋白的晶体     

Passage ofCorynebacterium aquaticum through membrane filters

Summary Cellulose ester and polycarbonate membrane filters were tested for sterilizing capability with a contaminant,Corynebacterium aquaticum, isolated from cell culture medium. This contaminant, often found in water supplies, routinely passes filters of the polycarbonate type, but not of the cellulose ester type.C. aquaticum grows slowly requiring 7 to 10 days incubation in BME at 37°C before turbidity develops. Cryptic contamination is potentially a serious problem with this organism. This work was supported in part by USPHS Grant 5 F32 CA05635-02 from the National Cancer Institute.