Albumin — vitamin D-binding protein haplotypes in Asian-Pacific populations

Summary We have determined the various haplotypic combinations between alleles as well as restriction fragment length polymorphisms of two linked genetic markers, albumin and vitamin D-binding protein or group-specific component, in a number of Asian-Pacific populations. Using the partial maximum likelihood method, we constructed a phylogenetic network from the haplotype frequencies to assess relationships among the populations sampled. No systematic linkage disequilibrium was detected between most of the combinations, suggesting a lack of operation of any selection pressure at the two loci. The phylogenetic analysis confirmed the known interrelationships among various populations in the Asian-Pacific region. The Australian aborigines clustered closely with the non-Austronesian-speaking highlanders from Papua New Guinea, as expected. Similarly, the Austronesian-speaking Polynesians, Micronesians, and the Southeast Asians branched off together as a separate group. The position of the Austronesian-speaking Tolais from New Britain with respect to other populations from the Southwest Pacific was anomalous. The Tolais revealed a strong affinity with the Australian aborigines, which is inexplicable. The populations from China formed a tight cluster with other populations from the Asian-Pacific region. Genetic interrelationships of these populations with the white Australians were remote, which is in accordance with the known affinities of various human racial groups.     

Interactions of chiral molecules with an (r)-n-(3,5-dinitrobenzoyl) phenylglycine HPLC stationary phase

Forty different chiral molecules were studied by liquid chromatography with a Pirkle-type, (R)-N-(3,5-dinitrobenzoyl) phenylglycine (DNBPG), chiral stationary phase column. The dramatic effect of a small molecular change on chiral recognition was demonstrated using DL-amino acid derivatives. The inductive effect on chiral recognition was also studied using trifluoro-, trichloro-, dichloro-, monochloroacetyl, and acetyl derivatives of four different chiral amines. The study of the enantiomer separation of 11 different crown ethers of 2,2′-binaphthyldiyl showed that the rigidity of the chiral center can be an additional parameter in chiral recognition for the DNBPG phase but not for a β-cyclodextrin bonded chiral phase. It is apparent from this study that steric effects, inductive effects, and molecular rigidity play important roles in chiral recognition with DNBPG chiral stationary phases.     

烟草抗黑胫病突变体的细胞筛选

经实验我们成功地建立了在细胞水平上筛选烟草抗黑胫病突变体的筛选体系。该体系的主要内容为:γ-射线500—2000拉德诱变高度感病品种的花药后用50—80％的黑胫病菌粗毒素为选择压力,筛选出抗毒素花粉植株,用离体叶片法测定选出抗病植株,再从后代鉴定中选出抗病性能够稳定遗传的突变系。γ-射线及高浓度毒素处理均能得到抗病植株。选自感病品种的花粉植株中约有9—50％是真正抗病的。这些抗病植株中有一部分的抗病性能够稳定遗传。用该法已从感病优质品种小黄金1025及乔庄黑苗中选出6个突变系。并自N.C.628(抗)×小黄金1025(感)及N.C.628(抗)×庆胜2号(感)的F_1花粉植株中选出4个抗病系。所有的抗病系经3—4代后均表现出稳定抗性。其中一个突变体(R400)的抗性似由不完全显性多基因控制。     

Presuturing--a new technique for closing large skin defects: clinical and experimental studies

We have developed a new technique termed presuturing for aiding in the closure of large skin defects which may have otherwise required a skin graft or flap. This technique is based on biomechanical properties of skin (creep, stress relaxation) which allow skin to stretch beyond its inherent extensibility. Presuturing is performed under local anesthesia and consists of plicating intact skin over the area of planned excision the night prior to operation. Experimental studies in a pig model showed the decrease in force required to close a standard-sized wound to be 40.1 percent less than control (p less than 0.001). Fourteen patients who underwent wide excision of skin lesions had their wounds presutured. All but one wound could be closed primarily without undermining. Presuturing seems to be an easy and clinically useful technique in aiding the primary closure of large defects.     

Inorganic-carbon uptake by a small-celled strain of Stichococcus bacillaris

Air-grown cells of a marine, small-celled (2 m diameter) strain of Stichococcus bacillaris contained appreciable carbonic-anhydrase activity but this was repressed when cells were grown on air enriched with 5% (v/v) CO₂. Assay of carbonic-anhydrase activity using intact cells and cell extracts showed all activity was intracellular in this Stichococcus strain. Measurement of inorganic-carbon-dependent photosynthetic O₂ evolution at pH 5.0, where CO₂ is the predominant form of inorganic carbon, showed that the concentration of inorganic carbon required for half-maximal rate of photosynthetic O₂ evolution [K_0.5(CO₂)] was 4.0 M for both air- and CO₂-grown cells. At pH 8.3 the K_0.5(CO₂) was 0.3 mM for air-grown and 0.6 mM for CO₂-grown cells. Sodium ions did not enhance bicarbonate utilization. Measurement of the internal inorganic-carbon pool (HCO ₃ ^– +CO₂) by the silicone-oil-layer centrifugal filtering technique showed that air- and CO₂-grown cells were able to concentrate inorganic carbon up to 20-fold in relation to the external medium at pH 5.0 but not at pH 8.3. In this alga the high affinity for CO₂ and inorganic-carbon accumulation in CO₂- and air-grown cells results from active CO₂ transport that is not dependent on carbonic-anhydrase activity.Abbreviation Hepes 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid     

The genomic relationship between cultivated sorghum [Sorghum bicolor (L.) Moench] and Johnsongrass [S. halepense (L.) Pers.]: a re-evaluation

Summary The genomic relationship between cultivated sorghum [Sorghum bicolar (L.) Moench, race bicolor, De Wet, 2n=20] and Johnsongrass [S. halepense (L.) Pers., 2n=40] has been a subject of extensive studies. Nevertheless, there is no general consensus concerning the ploidy level and the number of genomes present in the two species. This research tested the validity of four major genomic models that have been proposed previously for the two species by studying chromosome behaviors in the parental species, 30-chromosome hybrids [sorghum, (2n=20) x Johnsongrass, (2n=40)], 40-chromosome hybrids [sorghum, (2n=40) x Johnsongrass, (2n=40)] and 60-chromosome amphiploids. Chromosome pairings of amphiploids are reported for the first time. Chromosomes of cultivated sorghums paired exclusively as 10 bivalents, whereas Johnsongrass had a maximum configuration of 5 ring quadrivalents with occasional hexavalents and octovalents. In contrast, 40-chromosome cultivated sorghum had up to 9 ring quadrivalents and 1 hexavalent. Pairing in the 30-chromosome hybrids showed a maximum of 10 trivalents, and that in the 40-chromosome hybrids exhibited 8 quadrivalents, 5 of which were rings, together with a few hexavalents. Amphiploid plants showed up to 3 ring hexavalents, 1 chain hexavalent and a chain of 12 chromosomes. The data suggest that cultivated sorghum is a tetraploid species with the genomic formula AAB1B1, and Johnsongrass is a segmental auto-allo-octoploid, AAAA B1B1B2B2. The model is further substantiated by chromosome pairing in amphiploid plants whose proposed genomic formula is AAAAAA B1B1B1B1 B2B2.Contribution no. 87-391-J from the Kansas Agriculatural Experiment Station     

中国人线粒体DNA的八种限制酶图及其电镜结构

尽管Anderson等人(1981)已测定了人mtDNA的全部序列,但还不能全面地反映整个人类mtDNA核苷酸序列的情况。因此,在具有代表特征的中国人mtDNA序列被测定之前,为了开展对中国人mtDNA的遗传学研究,笔者构建了中国人mtDNA的8种限制酶图。并通过电镜技术对mtDNA进行了研究,发现了一种周长为2μm的小环状DNA,推测它可能在核DNA和mtDNA之间的信息传递或衰老发生中起到某些作用。     

泡状饶氏藻营养细胞的超微结构研究

本文报道我国特有的一种绿藻门植物－泡状饶氏藻营养细胞的超微结构特征,植物体由3层细胞组成,外层细胞最小,细胞质比较丰富,含有较多的各种细胞器,液泡体积较小,中层细胞具有很大的中央液泡,细胞质成为贴壁的薄层,各种细胞器结构仍清晰可见,内层细胞极度液泡化,细胞质呈现退化状态,周生的片状叶绿体上有许多大小不等的穿孔,使叶绿体呈网孔状外貌,叶绿体主要由许多成对的类囊体组成,叶绿体上往往有几个蛋白核,蛋白核经常被1或2条类囊体穿过,呈现分隔状,本文也报道了泡状饶氏藻的线粒体,质体,内质网,高尔基体和核内微管的结构特征,根据泡状饶氏藻的类囊体形态与Ulva mutabilis非常相似以及蛋白核的超微结构特征,它与石莼科植物可能有较密切的亲缘关系,属于绿藻门中进化的类群。