泥河湾层中新发现一处旧石器地点

半个多世纪以来,在泥河湾层中寻找早更新世时期的人类遗迹,已成为中、外许多科学家非常关心的一个问题。近几年来,在泥河湾村附近,大量古文化遗物从属于下更新统的泥河湾层中发现了。新的发现为旧石器时代考古学和第四纪地质学又增添了新的内容。     

昆明呈贡龙潭山第2地点的人化石和旧石器

在对呈贡县大渔区龙潭山第2地点的试掘中发现一枚人的下臼齿,它在形态上与现代人的不同,与北京猿人的也有所差别。它带有早期智人下第二乳臼齿的一些形态特征。一起发现的石制品中有石核、石片、砍砸器和刮削器。时代为晚更新世,距今30,500±800年。     

Catechol-O-methyltransferase: A method for autoradiographic visualization of isozymes in Cellogel

An electrophoretic procedure for separating the molecular forms of catechol-O-methyltransferase in cellulose acetate gel is described; the zones of enzyme activity were revealed by autoradiography. The electrophoretic patterns of the enzyme in several tissues and cell lines derived from four different species are presented.This investigation was supported by Grant 500.6/Ric. 70/1981 from the Italian Ministry of Health and by the Italian Ministry of Education. We are grateful to Dr. M. Castagnola for useful advice and help with thin-layer chromatography.     

Striated ciliary root-golgi association in branchial crown epithelial cells ofOwenia. Visualization of Ca2+-binding sites and ATPase activities

Summary Striated Ciliary Roots (SCRs), about 3 m long, are attached to the basal bodies of branchial crown ciliated epithelial cells ofOwenia. These SCRs appear to consist of 5–7-nm diameter filaments organized in a cross-striation pattern with an apparent variable periodicity of 50 to 80 nm. The most exciting observation emerging from this study is the constant and conspicuous close spatial relationship between SCRs and fairly well developed Golgi apparatus. By enhancing contrast and preservation of cell components, the OsFeCN postfixation-staining of material prefixed in glutaraldehyde in the presence of calcium has revealed some fine-structural details within the SCR-Golgi Association. By means of the calcium precipitation method, with antimonate or oxalate in conjunction with X-ray microanalysis, we have identified calcium within SCR dark bands and SCR-associated Golgi bodies. The ability to bind calcium makes the Golgi apparatus a likely candidate for Ca²⁺ regulation of putative contraction of the SCRs and/or ciliary motility. The slight period variability measured in the SCRs and cytochemical localization of Mg²⁺, Ca²⁺-dependent ATPase activities associated with cross striations support the view that theOwenia SCRs may be contractile organelles.The striking and specific close structural association between the Golgi apparatus and the SCR showing Ca²⁺-binding capabilities suggests that some sort of Ca²⁺-mediated functional relationship between these organelles may exist.Abbreviations SCR striated ciliary root - OsFeCN method osmium tetroxide-ferricyanide method - EDTA ethylenediamine tetraacetic acid - EGTA ethyleneglycol-bis-(-aminoethyl ether) N,N-tetraacetic acid - ATP adenosine 5-triphosphoric acid - ATPase adenosine triphosphatase - ASW artificial sea-water     

Theoretical studies on the necessary number of components in mixtures

Summary Theoretical studies on the necessary numbers of components in mixtures (for example multiclonal varieties or mixtures of lines) have been performed according to the relations between the juvenile-mature correlations of mixtures and their number of components. For the juvenile-mature correlation r_E based upon the values of the single components (= component means at juvenile and mature ages) and the juvenile-mature correlation r_M based upon the means of mixtures of different components we usually will have r_M>r_E. Furthermore, r_M will increase with an increasing number of components in the mixtures. The effectiveness of an early selection will be mainly determined by the magnitude of the juvenile-mature correlation. If we have r_M>r_E an improvement of early testing can be realized by using mixtures instead of single components. But, what are the necessary numbers of components so that r_M will be sufficiently high to enable an effective early selection of mixtures? Some relations between r_E and r_M can be obtained and conclusions have been derived.The statistical approach significant difference between r_E and r_M for a given numerical value of r_M leads to estimates for the necessary number n of components dependent on r_M, , r_E and N where: N = total number of components, which are available for the composition of mixtures and = error probability. For different tree species r_E can be estimated by an appropriate formula which depends on T with T = time (in years) from planting date until the mature age.Lambeth's formula, for example, has been developed for height growth in pines. For this situation numerical calculations are performed using r_M=0.90 and =0.05. The necessary numbers n for T=5, T=10, T=20 and T=50 are: 6, 9, 10 and 12 (for N=50); 13, 17, 20 and 23 (for N=100); 26, 34, 40 and 46 (for N=200); 38, 51, 60 and 69 (for N=300); 64, 85, 100 and 114 (for N=500) and 128, 171, 199 and 228 (for N=1,000). The dependence of these necessary numbers n of components on different type I errors and different levels of r_M have been investigated numerically.     

Breeding vervet monkeys in a closed environment

A breeding group of vervet monkeys produced 95 offspring over five years. Fetal wastage for 114 pregnancies was 16.7%. Uterine sizes were recorded for 103 pregnancies in various stages of gestation. This enabled diagnosis of pregnancy, estimation of stage of gestation, and prediction of parturition to within two weeks. Detailed observations were made on dental eruption, pelage development, and growth of 57 infants.     

Hypoplasia and health status: a comparison of two lifestyles

Enamel hypoplasia was recorded for the primary and permanent teeth of Natufians (terminal Pleistocene Hunter-Gatherers) and Early Arabs (Subsistence farmers). Minimal hypoplasia was found in the primary teeth of the Natufians, but in the Early Arab population, 31% of upper first primary molars showed enamel defects. In the permanent teeth, the Early Arab population again showed a significantly higher frequency of hypoplasia, with all teeth affected. In the Natufians, only later developing teeth showed enamel defects. These findings suggest that health status in the Early Arab population was poor throughout life, affecting pregnant mothers, their foetuses, young infants and children. These results confirm other studies that have shown deterioration in health status of early agriculturalists relative to hunter- gatherers. Comparisons of these findings with those of recent populations indicate that health status in the Natufians was comparable to that of modern populations with subsistence diets and mediocre health care. Health status in the Early Arab population was comparable to that of modern populations suffering from severe malnutrition and chronic disease.     

Vertebral pathology in the afar australopithecines

Ten vertebral elements from the AL-288 partial hominid skeleton and 11 elements from the AL-333 collection are described. The AL-288 column presents a marked kyphosis at the level of thoracic vertebrae 6 through 10, with pronounced new bone formation on the ventral surfaces of these vertebrae. These features, associated with narrowed disc space and minor osteophytosis, resemble Scheuermann disease in the human. Even though this diagnosis is consistent with a basically human, bipedal locomotor repertoire, the presence of Scheuermann disease suggests that lifting, climbing, or acrobatic activities may have been important in early hominids.     

Quantitative determination of 5-methylcytosine in DNA by reverse-phase high-performance liquid chromatography

A method to separate the four major bases (cytosine, guanine, thymine and adenine) and the two minor modified bases (5-methylcytosine and 6N-methyladenine) in DNA has been developed. For optimal separation, several different buffer systems are available for isocratic elution. The 12 5-methylcytosine (5-mC) residues in the plasmid pBR322 can be determined with a deviation of less than 3% of the expected value and have been used for internal standardization. Formic acid hydrolysis of bases and probably of DNA does not lead to the deamination of cytosine or 5-mC and thus can be used routinely for DNA hydrolysis. Adenovirus or baculovirus DNA does not contain detectable amounts of 5-mC. The distribution of 5-mC in hamster cell DNA appears to be nonrandom in that different 5'-CpG-3'-containing restriction sites are methylated to different extents.     

Acetylcholine and Choline in Neuronal Tissue Measured by HPLC with Electrochemical Detection

Abstract: A simple, rapid method is presented for the determination of acetylcholine (ACh) and choline (Ch) in neuronal tissue using HPLC with electrochemical detection. The method is based on the separation of ACh and Ch by reverse-phase HPLC and mixing the effluent as it emerges from the column with acetylcholinesterase and Ch oxidase, which converts endogenous Ch and Ch produced by the hydrolysis of ACh to betaine and hydrogen peroxide. Production of hydrogen peroxide is continuously monitored electrochemically. The sensitivity of the procedure is 1 pmol for Ch and 2 pmol for ACh. Specificity of the method is based on HPLC, two specific enzymatic reactions, and the detection of hydrogen peroxide.