分散角质层的分类和命名*

简略讨论了分散角质层对地层学、古生物学和古环境的意义;简述了气孔器的形态学、发生学和形态一发生学的分类;在介绍并讨论了分散角质层的分类原则和命名方法的基础上,提出了新的分类方案.     

Vntr Allele Frequency Distributions under the Stepwise Mutation Model: A Computer Simulation Approach

Variable numbers of tandem repeats (VNTRs) are a class of highly informative and widely dispersed genetic markers. Despite their wide application in biological science, little is known about their mutational mechanisms or population dynamics. The objective of this work was to investigate four summary measures of VNTR allele frequency distributions: number of alleles, number of modes, range in allele size and heterozygosity, using computer simulations of the one-step stepwise mutation model (SMM). We estimated these measures and their probability distributions for a wide range of mutation rates and compared the simulation results with predictions from analytical formulations of the one-step SMM. The average heterozygosity from the simulations agreed with the analytical expectation under the SMM. The average number of alleles, however, was larger in the simulations than the analytical expectation of the SMM. We then compared our simulation expectations with actual data reported in the literature. We used the sample size and observed heterozygosity to determine the expected value, 5th and 95th percentiles for the other three summary measures, allelic size range, number of modes and number of alleles. The loci analyzed were classified into three groups based on the size of the repeat unit: microsatellites (1-2 base pair (bp) repeat unit), short tandem repeats [(STR) 3-5 bp repeat unit], and minisatellites (15-70 bp repeat unit). In general, STR loci were most similar to the simulation results under the SMM for the three summary measures (number of alleles, number of modes and range in allele size), followed by the microsatellite loci and then by the minisatellite loci, which showed deviations in the direction of the infinite allele model (IAM). Based on these differences, we hypothesize that these three classes of loci are subject to different mutational forces.     

在中国壮族家系中发现的一例-α~T/-α~Q复合β~0β~0珠蛋白基因型

本文报道在我国广西隆林壮族中发现一个罕見的HbQ复合α,β地中海贫血家系。先证者女,18岁,贫血面容,肝脾肿大。化学结构分析确证本Hb变异体为HbQ Thailand[α74(EF3)Asp→His]。血红蛋白组成以及α和β珠蛋白基因分析结果表明,先证者的珠蛋白基因型为-α~Q/-α~T复合β°/β°(IVSI-1G→T/Codon17A→T);先证者父的基因型为-‘α~Q/-复合β~O/β~A(IVSI-1G→T/β~A);先证母的基因型为-α~T/αα复合β~O/β~A(Codon17A→T/β~A)。     

体外冲击波碎石术对兔肝酶活性的影响

采用超微组织化学方法,观察了体外冲击波碎石术(ESWL)对家免肝脏酶活性的影响。实施 ESWL 后,肝细胞的琥珀酸脱氢酶(SDH)和毛细胆管壁上的碱性磷酸酶(ALP)、焦磷酸硫胺素酶(TPPase)反应活性减弱或消失。TPPase 从损伤的肝细胞高尔基体分泌面扁囊、溶酶体样小泡和毛细胆管内溢出,并伴有肝细胞面的质膜上出现了 TPPase 反应产物和形成膜包内凹小泡。结果提示 ESWL 可对肝细胞及毛细胆管的功能和结构有损伤作用。     

沙门氏菌增菌培养基中细菌混合培养生长动力学的试验研究

本文就甘露醇亚硒酸盐和亚硒酸盐两种增菌培养基对沙门氏菌各血清变型的选择性增菌作用作了研究。研究述及37℃下沙门氏菌与埃希氏大肠杆菌、绿脓杆菌、普通变形杆菌三种竞争菌混合培养生长动力学过程,测出了评价增菌培养基优劣的客观指标EI值;按沙门氏菌传统分离方法,对加有终浓度为10~1、10~2、10~4、10~6、10~8个活菌/毫升的沙门氏菌株与正常人大便的两种增菌培养基,经37℃下孵育20至24小时后作SS琼脂平板划线分离和沙门氏菌血清学鉴定。通过两种培养基EI值及沙门氏菌分离结果的比较证实,甘露醇亚硒酸盐培养基对沙门氏菌株的选择性增菌作用明显优越于亚硒酸盐培养基(P<0.001)。     

Site and mechanism of behavioral tolerance to cocaine: A study of dopamine release in Wistar-Kyoto and spontaneously hypertensive rats

Wistar-Kyoto and spontaneously hypertensive rats received i.v. infusions of cocaine hydrochloride (60 mg/kg per day) for 3, 7, and 14 days, or saline for 7 days. Acute cocaine challenge (40 mg/kg, s.c.) was given to treated and control rats 24 hr after the termination of each infusion period. There were no strain differences in brain levels of cocaine during cocaine infusion, nor after cocaine challenges. There were no strain differences in resting levels of [³H]dopamine release. Release of [³H]dopamine decreased in nuclei accumbens of 7- and 14-day cocaine-infused animals. Release of [³H]dopamine was maximal in both brain regions 2 hr after acute cocaine challenge. After 14 days of cocaine infusion, cocaine challenge in both strains reduced [³H]dopamine release in the nucleus accumbens, but not in the striatum; the reduction being greater in Wistar-Kyoto rats. The behavioral tolerance which accompanies similar cocaine infusion regimens may be related to striatal tolerance to cocaine-induced dopamine release.     

Restudy of the upper age limit of Beijing Man site

The chronological position of Beijing Man site was restudied by U-series dating of two calcite samples taken from a stalagmitic flowstone layer intercalated in 1–2 layers. Based on the weighted mean of three measurements performed on the purer one, the upper age limit of this site be 421 ₋₅₄ ⁺¹¹⁰ ka B.P., much greater than former evaluation of 230 ka based on U-series dating of fossil bones. The reliability of the obtained results was discussed.     

The complex genome and adaptive evolution of polyploid Chinese pepper (Zanthoxylum armatum and Zanthoxylum bungeanum)

Zanthoxylum armatum and Zanthoxylum bungeanum, known as ‘Chinese pepper’, are distinguished by their extraordinary complex genomes, phenotypic innovation of adaptive evolution and species-special metabolites. Here, we report reference-grade genomes of Z. armatum and Z. bungeanum. Using high coverage sequence data and comprehensive assembly strategies, we derived 66 pseudochromosomes comprising 33 homologous phased groups of two subgenomes, including autotetraploid Z. armatum. The genomic rearrangements and two whole-genome duplications created large (~4.5 Gb) complex genomes with a high ratio of repetitive sequences (>82%) and high chromosome number (2n = 4x = 132). Further analysis of the high-quality genomes shed lights on the genomic basis of involutional reproduction, allomones biosynthesis and adaptive evolution in Chinese pepper, revealing a high consistent relationship between genomic evolution, environmental factors and phenotypic innovation. Our study provides genomic resources and new insights for investigating diversification and phenotypic innovation in Chinese pepper, with broader implications for the protection of plants under severe environmental changes.