Capitalist Philanthropy and Russian Revolutionaries: The Jesup North Pacific Expedition (1897-1902)

This review of the Jesup North Pacific Expedition, still the most important expedition in American anthropology, gives an idea of the goals and hazards of fieldwork around 1900, the pitfalls of international research, the tensions between anthropologists and host populations, the careers of early anthropologists, the role of private philanthropy, and the character of anthropology at the turn of the century. Franz Boas was the Expedition's linchpin. His organization of the Expedition, the way he handled problems, and his personal concerns reveal aspects of his view of anthropology and some of his basic attitudes.     

Sterol composition of a δ5,7-sterol-rich strain ofSaccharomyces cerevisiae during batch growth

Sterol composition was examined during batch growth on complex media containing ethanol, molasses or glucose as the carbon source. The molasses-grown cells exhibited a balanced sterol composition throughout growth, maintaining the proportion of ergosterol to 24:28-dehydroergosterol equal to 1.4. The negative effect of glucose on sterol synthesis manifested itself by decreasing the accumulation of 24:28-dehydroergosterol and total sterols but not of ergosterol. Using ethanol as the sole carbon source, a large amount of 24:28-dehydroergosterol accumulated, partly at the expense of other sterols. The gradual addition of nitrogen source during growth significantly decreased the accumulation of ergosterol, 24:28-dehydroergosterol and of total sterols. A general scheme of regulation of sterol synthesis in baker's yeast is presented.     

Solubilization of the bovine cardiac sarcolemmal binding sites for calcium channel blockers

Nonionic and ionic detergents were used to solubilize the bovine cardiac sarcolemmal binding sites for nimodipine and (-)desmethoxyverapamil in the absence of added ligand. Only Chaps, digitonin and sucrose monolauryl ester were able to solubilize the binding sites in a form that bound radioligands. About 45% of each of the membrane-bound high-affinity site was solubilized by 0.4% Chaps (w/v) in the presence of 48% (w/v) glycerol. The solubilized binding sites were destroyed by trypsin or by a 10-min incubation at 50 degrees C. Calcium stimulated nimodipine binding slightly at 0.3 mM and inhibited (-)desmethoxyverapamil binding completely with an IC50 of 1.2 mM. Nimodipine binding was reduced by 20% in the presence of EGTA. The solubilized receptors sedimented in sucrose density gradients with an apparent s20,w of 21 S. An identical sedimentation value was obtained for the cardiac sarcolemmal and skeletal transverse tubulus receptor which were prelabeled with nitrendipine and solubilized by digitonin. Solubilization reduced the affinity of nimodipine for its high-affinity site slightly from 0.35 nM to 1.2 nM and that for its low-affinity site from 33 nM to 130 nM. Solubilization did not affect significantly the specific density of these sites. Binding of nimodipine to the low-affinity site was completely abolished by 0.1 microM nitrobenzylthioinosine. After solubilization only the high-affinity site for (-)desmethoxyverapamil could be measured with tenfold reduced affinity (Kd = 15.3 nM) but unchanged specific density. Binding to the solubilized high-affinity site for nimodipine and (-)desmethoxyverapamil was stereospecific and showed a similar rank order as the particulate binding sites. Binding of nimodipine was inhibited allosterically by phenylalkylamines. Similarly, (+)PN200-110 inhibited allosterically (-)desmethoxyverapamil binding. d-cis-Diltiazem stimulated nimodipine binding at 20 degrees C 1.2-fold, reduced the dissociation rate from 0.018 min-1 to 0.0083 min-1 and had no effect on the association rate (0.173 min-1. nM-1). The Kd calculated from the rate constants was 0.1 nM and in close agreement with the value of 0.49 nM measured under equilibrium conditions in the presence of nitrobenzylthioinosine. In contrast, desmethoxyverapamil increased the dissociation rate of nimodipine to 0.03 min-1. The association and dissociation rate constants for (-)desmethoxyverapamil were 0.024 min-1. nM-1 and 0.025 min-1, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)     

Cardiac sarcoplasmic reticulum contains a low-affinity site for phenylalkylamines

The distribution of the bovine cardiac binding sites for the organic calcium-channel blockers was studied. Crude microsomal membranes were separated into three fractions, which contained mainly membranes derived from sarcolemma, 'junctional' sarcoplasmic reticulum containing transversal tubuli, and free sarcoplasmic reticulum. The high-affinity binding site for the dihydropyridines, determined in the presence of nitrobenzylthioinosine, was enriched 12-fold and 17-fold in sarcolemma and junctional sarcoplasmic reticulum. The binding sites for the phenylalkylamines, determined with [3H]verapamil or [3H](-)desmethoxyverapamil, were enriched 1.5-3.4-fold in sarcolemma and junctional sarcoplasmic reticulum but 6-10-fold in free sarcoplasmic reticulum. The phenylalkylamine-binding site, present in free sarcoplasmic reticulum, was partially destroyed by chymotrypsin or phospholipase A2 and C treatment. Specific binding was proportional to the concentration of the added membrane protein. The binding of (-)desmethoxyverapamil was half-maximally inhibited by 6.5 mM calcium chloride and was optimal in the presence of 5 mM EGTA. In three out of five preparations (-)desmethoxyverapamil bound to a single site with an apparent Kd value of 191 +/- 42.8 nM and a density of 34.5 +/- 7.7 pmol/mg protein. In two out of five preparations an additional high-affinity site (Kd approximately 0.67 nM) was detected. The low-affinity site bound other phenylalkylamines, but stereospecific binding of phenylalkylamines was not observed. Binding of phenylalkylamines to the low-affinity site was inhibited by some but not all calmodulin 'antagonists'. Furthermore dihydropyridines did not affect the binding of (--)desmethoxyverapamil suggesting that the low-affinity site differs considerably from the high-affinity sarcolemmal site. These results suggest that free sarcoplasmic reticulum contains a binding site for phenylalkylamines at a relative high density, which is not related to the high-affinity site present in the voltage-dependent calcium channel.     

Saprophytic production of Clavine alkaloids and activity of Hydroxymethylglutaryl-CoA reductase

In submerged Claviceps cultures the activity of hydroxymethylglutaryl-CoA reductase preceded the increase of alkaloid production and of sterol content. During the first alkaloid phase, cell mevalonate was involved in the biosynthesis of both alkaloids and steroids. In the second production phase, it was predominantly used for alkaloid synthesis. Hydroxymethylglutaryl-CoA reductase appears to be a suitable target for physiological manipulation to increase clavine alkaloid yields.     

The Genetics of the DORSAL-BICAUDAL-D Region of DROSOPHILA MELANOGASTER

The chromosomal region 36C on 2L contains two maternal-effect loci, dorsal (dl) and Bicaudal-D (Bic-D), which are involved in establishing polarity of the Drosophila embryo along the dorsal-ventral and anterior-posterior axes, respectively. To analyze the region genetically, we isolated X-ray-induced dorsal alleles, which we recognized by virtue of the haplo-insufficient temperature-sensitive dorsal-dominant phenotype in progeny of single females heterozygous for a mutagenized chromosome. From the 20,000 chromosomes tested, we isolated three deficiencies, two inversions with breakpoint in dl and one apparent dl point mutant. One of the deficiencies, Df(2L)H20 (36A6,7; 36F1,2) was used to screen for EMS-induced lethal- and maternal-effect mutants mapping in the vicinity of dl and Bic-D. We isolated 44 lethal mutations defining 11 complementation groups. We also recovered as maternal-effect mutations four dl alleles, as well as six alleles of quail and one allele of kelch, two previously identified maternal-effect genes. Through complementation tests with various viable mutants and deficiencies in the region, a total of 18 loci were identified in an interval of about 30 cytologically visible bands. The region was subdivided into seven subregions by deficiency breakpoints. One lethal complementation group as well as the two maternal loci, Bic-D and quail, are located in the same deficiency interval as is dl.     

人体急性缺氧性意识障碍

实验分为低压组(低压舱7,000米)与常压组(吸入7.6％低氧混合气),每组受试者各为12名,有7名参加了两组实验。每组各有4名平均经15分23秒发生了意识模糊或丧失(通称意识障碍)。障碍者的肺泡氧分压为29.9±0.8mmHg。障碍发生前,呈现严重无力,觉醒度降低,反应迟钝,脑波特征是高幅6波(100-300μV)占优势。障碍发生时,高幅δ波丧失节律,幅度衰减,波型不规则,额枕失同步;呼吸循环代偿功能增强程度明显高于障碍前。本工作对于预测和评价人体急性缺氧引起的意识障碍有意义。     

青年昼间发汗调定点正常值探讨

以加热腿足诱发前臂屈侧初始发汗的口腔温度阈值,作为发汗调定点的参考值(ToSSP),检测健康青年93人夏冬两季昼间ToSSP134次。结果表明,季节、性别、民族、于室温24℃左右变异达30％的相对湿度对ToSSP均无显著影响。提示ToSSP为一间接反映体温调定点较发汗率为稳定的指标。ToSSP的频数分布属于正态,均值为37.34℃,95％正常值范围为36.97～37.71℃。经于本工作前,后年份检测的两组结果以及与正常体温夜间最低时相组和发热患者组的ToSSP相验证,证明此正常值范围可靠。检测ToSSP的潜伏期夏季均值为19′57″冬季为18′22″(P<0.05)。检测ToSSP时口温变化分别与皮肤温、心率变化紧密相关,因而心率,皮肤温可作为监测ToSSP的辅佐指标。     

Control of ventilation in extreme-altitude climbers

Ten climbers who participated in the Nepal-Japan Kangchenjunga Expedition (altitude, 8,478-8,586 m) in 1984 were examined for their hypercapnic and isocapnic hypoxic ventilatory responses (HCVR and HVR) at sea level before and after the expedition. Five climbers who reached an altitude higher than 8,000 m, [designated high-performance climbers (HPC)] exhibited significantly higher HVR than five climbers who did not [low-performance climbers (LPC)]. On the other hand, no significant difference in HCVR was seen between HPC and LPC. Our results were in agreement with the findings reported by Schoene et al. (J. Appl. Physiol. 56: 1478-1483, 1984) obtained in the American Medical Research Expedition to Everest in 1981. Significant depression in HVR in five climbers was found even 35-40 days after the expedition, which was accompanied by decreased arterial partial pressure of CO2 and increased pH at rest. Hence, the effect of altitude acclimatization in the climbers exposed to extreme altitude may have still persisted at the time of the postexpedition study. Our results confirmed that HRV evaluated at sea level may be used as an indicator of a climber's capability at great high altitude.     

Structural wrinkles and the genomic regulatory sites of eukaryotes

Summary Calculations of DNA angular parameters in 50 eukaryotic sequences reveal regions of large conformational deviations from ideal DNA around regulatory sites. Frequently, discrete peaks of structural variation are present upstream of genes. Known regulatory regions often include variants of consensus sequences. Thus, imprecise sequences and structures are recognized within large genomic stretches. The existence of structurally wrinkled regions in the vicinity of regulatory sequences is likely to facilitate greatly their recognition by proteins and enzymes.