满族新生儿血红蛋白F中G_γ／A_γ比值测定及其异常者γ－珠蛋白基因图谱分析

以聚丙烯酰胺凝胶电泳方法测定了３３１例辽宁满族新生儿脐带血血红蛋白Ｆ中Ｇγ／Ａγ比值。结果显示：高Ｇγ（＞８０％）者４例,占１．２１％,其基因频率（ｆ）为０．００６０４,低Ｇγ（３０－４８％）者６例,占１．８１％,其基因频率为０．００９０６,其余正常,Ｇγ平均值为６５．２３±６．３８％。未发现ＡγＴ链。对其中八例异常者（４例高Ｇγ值,４例低Ｇγ值）的染色体ＤＮＡ进行了基因图谱分析,确定４例高Ｇγ值者基因型有两种：Ｇγ－Ｇγ／Ｇγ－Ａγ二例,Ｇγ－ＡＧγ－Ａγ／Ｇγ－Ａγ二例;４例低Ｇγ值者基因型有二种,分别为：Ａγ－Ａγ／Ｇγ－Ａγ二例和－ＧＡγ／Ｇγ－Ａγ二例。其中Ａγ－Ａγ基因型在中国人群中未见报道过。     

Esterification of 2-methylalkanoic acids Catalysed by Lipase from Candida rugosa: Enantioselectivity as a Function of water Activity and Alcohol Chain Length

Esterifications catalysed by immobilised lipase from Candida rugosa (CRL) in cyclohexane at constant water activity (a_w = 0.76) were studied using 2-methyl substituted octa-, nona- or decanoic acids and n-alcohols of varying chain length as substrates. The importance of controlling the water activity and choosing the right alcohol for obtaining maximum enantioselectivity is demonstrated. The immobilised lipase was easily recovered without loss of activity and enantioselectivity.     

Mother-infant bonding

A study of the research on postpartum mother-infant bonding shows that results from poorly constructed research programs were published in major journals and became a part of hospital policy because the bonding concept was politically useful in the struggle between advocates of natural childbirth and managers of the medical model of birth. The concept was also uncritically accepted because it was consistent with a longstanding ideology of motherhood that sees women as the prime architects of their children’s personalities. Diane Eyer earned her Ph.D. in developmental psychology from the University of Pennsylvania. She is currently writing a book on the ways in which the concepts of bonding and attachment have affected our understanding of appropriate early childcare.     

Choline derivatives and sodium fluoride protect acetylcholinesterase against irreversible inhibition and aging by DFP and paraoxon

A light addressable potentiometric sensor was used to measure acetylcholinesterase (AChE) activity in order to evaluate the protective effects of quaternary compounds and NaF against enzyme phosphorylation and aging by two organophosphates. The use of the immobilized AChE made possible the quick removal of reagents (i.e., organophosphate, 2-pralidoxime, and protectant), thereby permitting accurate determination of AChE activity before and after phosphorylation and aging. Paraoxon was 15-fold more potent in inhibiting AChE than DFP, while the percent aging following phosphorylation by diiso-propylfluorophosphate (DFP) was much higher. Sodium fluoride (NaF), the most effective protectant against phosphorylation and aging, and the quaternary ammonium compounds reduced significantly AChE inhibition by DFP and paraoxon, to similar degrees. Even though the percent AChE activity that was lost to aging was reduced by these agents, aging as a percent of phosphorylated AChE was not reduced. Thus, their major effect was in reducing the percent AChE phosphorylation, which consequently resulted in reduction of total aged AChE. The finding that quaternary ammonium compounds protect against phosphorylation is consonant with the proposed presence of the active site of AChE in an aromatic gorge.     

Submerged vascular plants and water chemistry in the coastal marsh Albufera de Mallorca (Balearic Islands)

Ten species of aquatic macrophytes have been analyzed for seven environmental variables by means of a significance test. A synthetic view has been obtained through a cluster analysis for species and a principal component analysis for 17 variables which form the multidimensional space where we project the species habitats. Myriophyllum spicatum L., Najas marina L., Potamogeton crispus L., Potamogeton pectinatus L. and Zannichellia pedunculata Reichenb. are widely distributed in the Albufera. Ceratophyllum submersum L. and Ruppia maritima L. var. brevirostris Ag. are considered stenoic. The tolerance of Ceratophyllum submersum to salts is significantly low and that of Ruppia cirrhosa (Petagna) Grande and Ruppia maritima var. brevirostris significantly high. Ceratophyllum submersum has a significantly negative distribution with regard to chlorophyll a and phosphate concentrations. Ceratophyllum demersum L. and C. submersum primarily occur in nitrate-rich waters whereas Ruppia cirrhosa primarily occurs in low nitrate waters.     

Whole-cell recording of neuroblastoma x glioma cells during downregulation of a major substrate, 80K/MARCKS,of protein kinase C

Summary Differentiated neuroblastoma cells exhibit both the delayed rectifier potassium current (I _K) and the M-current (I _M). The present study was designed to determine the roles of protein kinase C (PKC) and of the calmodulin-binding protein 80K/MARCKS, a prominent substrate for PKC and possible regulator of these currents. Neuroblastoma x glioma (NG108-15) hybrid cells transfected with m1 muscarinic receptors were grown with 1% fetal bovine serum (FBS) without the prostaglandin E₁ (PGE₁) and isobutylmethylxanthine (IBMX) usually added in preparation for electrophysiological studies. Under these conditions, the usual pleomorphism was largely abolished, leaving two populations of small cells with stellate and spherically symmetrical geometries. Whole-cell patch clamping indicated that the two cell types had identical electrophysiological properties, displaying: I _k, a small current through a T-like Ca²⁺ channel, and no M-current.Stimulation with carbachol shifted the distribution of cells to a more stellate morphology within 24 hr and later (after 48 hr) reduced the PKC substrate 80K/MARCKS by 22±7%. In contrast to the stimulation of I _k observed with cardiac cells, PKC activation produced only a small inhibition of I _k, which was independent of carbachol pretreatment. Thus, PKC and 80K/MARCKS can be dissociated from the regulation of I _k in neuroblastoma cells.Supported in part by research grants from the National Institutes of Health (DK-40145 and EY-08343) and from the U.K. Medical Research Council.We thank Dr. Peter J. Parker for his generous gift of PKC, and Yvonne Vallis for her skillful assistance with the cultures and harvesting of the NG108-15 transfected cells.     

Calcium/Calmodulin-Stimulated Protein Kinase II Is Present in Primary Cultures of Cerebral Endothelial Cells

Abstract: Calcium/calmodulin-stimulated protein kinase II (CaMPK II). a major kinase in brain, has been established to play an important role in neurotransmitter release and organization of postsynaptic receptors, and it is known to be involved in long-term potentiation and memory. Less is known about the function of this enzyme in nonneural cells. Here we report on the production, presence, and phosphorylation of the α-subunit of CaM-PK II in primary cultures of cerebral endothelial cells. These results raise the possibility that α-CaM-PK II can act as one of the key enzymes of calcium-mediated intracellular signaling in the cerebral endothelial cells and suggest that α-CaM-PK II may participate in such basic cellular processes as permeability in physiological and pathological conditions.     

Studies on the Role of B-50 (GAP-43) in the Mechanism of Ca2+-Induced Noradrenaline Release: Lack of Involvement of Protein Kinase C After the Ca2+ Trigger

Abstract: The involvement of B-50, protein kinase C (PKC), and PKC-mediated B-50 phosphorylation in the mechanism of Ca²⁺-induced noradrenaline (NA) release was studied in highly purified rat cerebrocortical synaptosomes permeated with streptolysin-O. Under optimal permeation conditions, 12% of the total NA content (8.9 pmol of NA/mg of synaptosomal protein) was released in a largely (>60%) ATP-dependent manner as a result of an elevation of the free Ca²⁺ concentration from 10^?8 to 10^?5M Ca²⁺ The Ca²⁺ sensitivity in the micromolar range is identical for [³H]NA and endogenous NA release, indicating that Ca²⁺-induced [³H]NA release originates from vesicular pools in noradrenergic synaptosomes. Ca²⁺-induced NA release was inhibited by either N- or C-terminal-directed anti-B-50 antibodies, confirming a role of B-50 in the process of exocytosis. In addition, both anti-B-50 antibodies inhibited PKC-mediated B-50 phosphorylation with a similar difference in inhibitory potency as observed for NA release. However, in a number of experiments, evidence was obtained challenging a direct role of PKC and PKC-mediated B-50 phosphorylation in Ca²⁺-induced NA release. PKC pseudosubstrate PKC_19-36, which inhibited B-50 phosphorylation (IC₅₀ value, 10^?5M), failed to inhibit Ca²⁺-induced NA release, even when added before the Ca²⁺ trigger. Similar results were obtained with PKC inhibitor H-7, whereas polymyxin B inhibited B-50 phosphorylation as well as Ca²⁺-induced NA release. Concerning the Ca²⁺ sensitivity, we demonstrate that PKC-mediated B-50 phosphorylation is initiated at a slightly higher Ca²⁺ concentration than NA release. Moreover, phorbol ester-induced PKC down-regulation was not paralleled by a decrease in Ca²⁺-induced NA release from streptolysin-O-permeated synaptosomes. Finally, the Ca²⁺- and phorbol ester-induced NA release was found to be additive, suggesting that they stimulate release through different mechanisms. In summary, we show that B-50 is involved in Ca²⁺-induced NA release from streptolysin-O-permeated synaptosomes. Evidence is presented challenging a role of PKC-mediated B-50 phosphorylation in the mechanism of NA exocytosis after Ca²⁺ influx. An involvement of PKC or PKC-mediated B-50 phosphorylation before the Ca²⁺ trigger is not ruled out. We suggest that the degree of B-50 phosphorylation, rather than its phosphorylation after PKC activation itself, is important in the molecular cascade after the Ca²⁺ influx resulting in exocytosis of NA.     

Effect of Watering Regimen on Injury to Corn and Grain Sorghum by Pratylenchus Species

The effect of simulated rainfall frequency on the pathogenicity of Pratylenchus zeae and P. brachyurus was studied in four greenhouse experiments. Corn and grain sorghum were watered at different intervals during predetermined cycles to create a gradient of water-stressed plants. Each experiment included nematode and uninoculated treatments. Growth reaction of plants to different frequencies of watering was significant but was not affected by the presence of nematodes. Pratylenchus zeae numbers differed among watering regimens on corn but not on sorghum. Numbers of P. brachyurus did not differ among watering regimens on corn or sorghum. Both lesion nematode species were harmful to corn, but sorghum increased plant growth in response to P. brachyurus. It is concluded that water stress is not the only environmental factor that influences the pathogenicity of these two species on corn and sorghum.