Skin colorimetry in Belize. I. Conversion formulae

Comparisons between skin colorimetry reports have been hampered by the common use of two different types of portable reflectometers, which sample reflectances at different wavelengths. In an attempt to provide direct comparability between the two machines, multiple linear regression equations were derived from reflectance spectrophotometry readings on 308 Black Caribs and 175 Creoles in Belize, Central America, using both machines. Cross validation tests show the coefficients presented are applicable to independent data sets and generally applicable to other heavily pigmented populations. Comparisons with previously published conversion formulae, which were from very small samples using simple linear regression, show a definite improvement in predictive accuracy when using multiple regression equations based on a large sample.     

Kultivierung von isogenen E. coli-Stämmen

The strains E. coli C 600 and E. coli C 600 pL CR 665-58 were cultivated on a glucose containing nutrient medium. The cell states of the cell cycle were investigated by means of phased cultivation. The doubling time and the specific carbon-substrate consumption of cells were higher when E. coli C 600 pL CR 665-58 was used. During cell doubling cell states characterized by different specific carbon-substrate consumption coefficients were observed. By adaptation of carbon-substrates supply to the repetitive cell states during continuous cultivation of synchronized bacteria populations the efficiency of cell-mass production was increased by 15 percent.     

Long-term changes in the chromosomal inversion polymorphism of Drosophila subobscura. I. Mediterranean populations from southwestern Europe

The chromosomal polymorphism of seven Mediterranean populations of Drosophila subobscura has been compared with that of the same populations collected 26 to 35 years ago. Significant latitudinal clines for the frequencies of A(ST), E(ST), O(ST). and U(ST) chromosomal arrangements have been detected in the old and new samples. Standard gene arrangements are frequent in the north and decrease in frequency towards the south. Significant negative regression coefficients between latitude and transformed frequency have also been observed for the more frequent nonstandard gene arrangements. The pattern of the clines is practically the same in the old and new collections. Furthermore, the frequencies of gene arrangements of all chromosomes have changed significantly during this period in a systematic way: an increase in the frequency of those arrangements typical of southern latitudes and a decrease for those more common in northern latitudes is observed in all populations. These changes could be due to climatic factors that are correlated with latitude, making the chromosomal composition of this species more "southern.'     

Quantitative Analyses of Interbreeding in Populations of vannus-Morphotype Euplotes, with Special Attention to the Nominal Species E. vannus and E. crassus

ABSTRACT. Classical genetic techniques were applied to clonal cultures of the Euplotes vannus-crassus-minuta sibling species complex in an effort to provide some resolution to the species problem among these hypotrichs. Complex mating interactions were observed among clonal stock cultures derived from samples collected from sympatric and allopatric populations in a wide geographic survey. These results suggested that the classical model for the mating type inheritance and determination in these Euplotes is necessary but not sufficient to describe the mating mating interactions among populations of these ciliates. Successful conjugation between the nominal species E. crassus and E. vannus was observed routinely, and crosses between these two nominal species did not differ significantly from those among the other clonal stock cultures with respect to mating intensity and exconjugant survival. Data from backcrosses suggests that E. vannus and E. crassus can and do exchange genes. Based upon these data, we conclude that E. vannus and E. crassus comprise a single, highly polymorphic species with countless small populations, among which incomplete genetic exchange takes place.     

The genetic consequences of selection in natural populations

The selection coefficient, s, quantifies the strength of selection acting on a genetic variant. Despite this parameter's central importance to population genetic models, until recently we have known relatively little about the value of s in natural populations. With the development of molecular genetic techniques in the late 20th century and the sequencing technologies that followed, biologists are now able to identify genetic variants and directly relate them to organismal fitness. We reviewed the literature for published estimates of natural selection acting at the genetic level and found over 3000 estimates of selection coefficients from 79 studies. Selection coefficients were roughly exponentially distributed, suggesting that the impact of selection at the genetic level is generally weak but can occasionally be quite strong. We used both nonparametric statistics and formal random‐effects meta‐analysis to determine how selection varies across biological and methodological categories. Selection was stronger when measured over shorter timescales, with the mean magnitude of s greatest for studies that measured selection within a single generation. Our analyses found conflicting trends when considering how selection varies with the genetic scale (e.g., SNPs or haplotypes) at which it is measured, suggesting a need for further research. Besides these quantitative conclusions, we highlight key issues in the calculation, interpretation, and reporting of selection coefficients and provide recommendations for future research.     

Invasibility or invasiveness? Effects of habitat, genotype, and their interaction on invasive Rhododendron ponticum populations

The extent and nature of biological invasions are mainly influenced by either the genotype of the invading species, the suitability of the new habitat or by genotype-habitat interactions expressed in adaptations to the new environment. The relevance of these factors was assessed for the invasive evergreen shrub Rhododendron ponticum. Habitat characteristics of soil, climate and community properties were analysed in six native populations in both Georgia (Caucasus) and Spain and in six invasive ones in Ireland. Growth variables of rhododendron individuals and seedling occurrences in the field served as response variables. We performed a reciprocal transplant experiment with rhododendron cuttings and determined survival of transplants in all countries. Due to low survival rates in Georgia and Spain, vegetative increase was only analysed for Ireland. The Irish sites benefited from significantly higher nutrient supply than the Spanish and Georgian sites. We found both strong positive correlations of nutrient supply and negative correlations of seasonal temperature amplitude with growth variables of shoots and seedling density. Origin, target site and interaction effects were significant in the survival of transplanted rhododendron individuals. The Irish site was more favorable for all genotypes, but the invasive genotypes did not perform better than the native ones. The total increase in shoot length of transplants in Ireland was highest in the Irish genotypes, which might suggest adaptation of the Irish populations to their new area. In conclusion, we found evidence for invasiveness of Irish Rhododendron ponticum populations, but only in the invaded habitat. Nonetheless, habitats in the new range also seem to be well suited to native Spanish populations, supporting the idea that invasibility of these new sites also contributes to rhododendron invasion success.     

Partition of Old Murein in Small Patches over the Entire Wall of E. coli Cells Forced to Grow as a Coccoid

With the development of a technique to visualize the ages of different portions of the sacculus, De Pedro et al. showed that the sacculus of Escherichia coli was tripartite: (i) the establish poles contained only old wall, (ii) the nascent poles (or septa) were composed entirely of new murein, and (iii) the elongating cylindrical wall was a mixture of patches of both old and new peptidoglycan. This short note presents a computer analysis of data files of work presented in the recent paper by De Pedro et al. of the growth pattern of the wall of E. coli forced to grow in a quite unusual morphology as large spheres in the presence of mecillinam. Compared with rod-shaped cells, only very small patches (spikes) of old wall were retained interspersed with new murein during the conversion to large spheroids. This subdivision appeared to be the case for both the previous wall of the poles, which are ordinarily retained intact, and the previous patches retained within the cylindrical wall. These very small patches after the conversion to spheroids were much smaller than the sidewall patches in rod-shaped cells reported previously. This implies that the mechanism that prevents the insertion of new wall into both the wall of the poles and the old wall patches of the sidewall in the presence of mecillinam is superseded by insertion throughout the old wall. The work in the De Pedro et al. paper from 2001 was done with cells of same strain as in the earlier papers with rod-shaped cells, so the results of computer analysis of the fluorescence micrographs can be critically compared.     

Study of electrophoretic variability in Epipactis helleborine (L.) Crantz,E. palustris (L.) Crantz and E. microphylla (Ehrh.) Swartz (fam. Orchidaceae)

Allozymic variation in seven enzymes coded by eight loci was studied in seven populations of terrestrial Epipactis orchids, including four populations of E. helleborine, one population of E. palustris and two of E. microphylla, from Latium (Central Italy).Heterozygosity estimates reveal that E. helleborine (EH) is the most variable species (HET=0.233; P=0.59; A=1.8), followed by E. palustris (EP) (HET=0.085; P=0.29; A=1.3) while E. microphylla (EM) is monomorphic for all the loci examined.It is suggested that the two EM populations examined, with a total lack of genetic variability, could originate from the same genetically impoverished ancestral population. Also the low variability amount of EP can be ascribed to genetic drift, probably due to a founder event.Nei's identity coefficients were also calculated. These show a high similarity in EH (=0.987) and EM (=1.000) populations. Average identity value between EP and EM is 0.289, between EP and EH is 0.336 and between EM and EH is 0.784. These data reveal that E. palustris presents a remarkable genetic, besides geographical and ecological, differentiation.     

大肠杆菌表达的戊型肝炎病毒ORF2多肽对恒河猴的免疫保护研究

在大肠杆菌中表达的一段戊型肝炎病毒（HEV）结构蛋白NE2,纯化后以弗氏佐剂,按0d,10d,30d的方案10μg/针的剂量免疫3只恒河猴,在第2周抗体阳转,第6周时1只滴度达1∶100 000,另2只滴度1∶20 000,此时以106 PCR滴度的HEV病毒粪悬液攻击。对照组3只均出现血清转氨酶（ALT）升高,抗体阳转,粪便持续排毒1月以上;疫苗组无一发病,未检出非疫苗来源的抗体,其中1只始终未检出粪便排毒,另2只仅出现短暂排毒。以一份NE2免疫后猴血清（滴度1∶20 000）与103 PCR滴度的病毒混匀后感染2只恒河猴,结果对照组2只均持续排毒3周以上,抗体阳转,1只ALT明显升高;而抗体中和组2只猴始终未检出粪便排毒,抗NE2抗体缓慢下降,ALT正常。这些结果表明NE2具有良好的免疫原性和免疫保护性,有可能成为有效的戊肝疫苗。     

长期指数选择的遗传效果分析—计算机模拟研究

本文利用Monte Carlo模拟技术研究比较了普通选择指数、实际选择指数、约束指数和单性状选择四种方法的长期选择效果及对群体遗传结构的影响。50世代的结果表明:群体大小和遗传参数能明显影响长期指数选择的反应;实际指数选择是有效的,其总体效果好于普通指数;约束选择的早期反应虽低于普通指数,但后期效果好,而且对群体遗传结构影响较小。同时,指数选择使性状加性遗传方差和遗传力衰减变化,而遗传相关依指数公式的系数呈定向改变。建议多性状长期选择时应用实际指数法或约束指数法。     

Sequencing the botulinum neurotoxin gene and related genes in Clostridium botulinum type E strains reveals orfx3 and a novel type E neurotoxin subtype

Three Clostridium botulinum type E strains were sequenced for the botulinum neurotoxin (BoNT) gene cluster, and 11 type E strains, representing a wide biodiversity, were sequenced for the bont/E gene. The total length of the BoNT/E gene cluster was 12,908 bp, and a novel gene (partial) designated orfx3, together with the complete orfx2 gene, was identified in the three type E strains for the first time. Apart from orfx3, the structure and organization of the neurotoxin gene cluster of the three strains were identical to those of previously published ones. Only minor differences (≤3%) in the nucleotide sequences of the gene cluster components were observed among the three strains and the published BoNT/E-producing clostridia. The orfx3, orfx2, orfx1, and p47 gene sequences of the three type E strains shared homologies of 81%, 67 to 76%, 78 to 79%, and 79 to 85%, respectively, with published sequences for type A1 and A2 C. botulinum. Analysis of bont/E from the 14 type E strains and 19 previously published BoNT/E-producing clostridia revealed six neurotoxin subtypes, with a new distinct subtype consisting of three Finnish isolates alone. The amino acid sequence of the subtype E6 neurotoxin differed 3 to 6% from the other subtypes, suggesting that these subtype E6 neurotoxins may possess specific antigenic or functional properties.     

Chronorhythms of the circulating erythrocytes and leukocytes--correlation with the E.S.R. cycles

2750 healthy and fasting subjects, 20-30 years old, were studied over a half-year period in 1980. Considering the mean day value as a basic piece of information for statistics, the Erythrocyte Sedimentation Rate (E.S.R.) and the blood counts (erythrocytes, leukocytes, polymorphonuclears, lymphocytes, monocytes and eosinophils) were compared. The timeless relation between E.S.R. and each cell type number or percentage is rectilinear. The stronger slope and relation apply to the polymorphonuclears (PMN) or to the overall leukocytes. The chronological normalized variations of the E.S.R. and of the PMN or leukocyte number or percentage are highly correlated. E.S.R. is less correlated with monocytes, eosinophils and Lymphocytes. Contrary to what could have been expected, the erythrocyte situation is but an intermediate one. The spectra derived from the time variations show that all the cell types, whatever they are, are to be taken into account to explain the E.S.R. value and variation with time, even if, for a given cell type, the correlation and timeless relation were but faint ones. Each cell type has a specific spectrum. Erythrocytes are subject to low frequency variations (316-158 days). PMNs oscillate with time within the medium frequency range (90 days). Lymphocytes, monocytes and eosinophils fluctuate more quickly (53 days).     

Vitamin E in human skin: organ-specific physiology and considerations for its use in dermatology

Vitamin E has been used for more than 50 years in experimental and clinical dermatology. While a large number of case reports were published in this time, there is still a lack of controlled clinical studies providing a rationale for well defined dosages and clinical indications. In contrast, advances in basic research on the physiology, mechanism of action, penetration, bioconversion and photoprotection of vitamin E in human skin has led to the development of numerous new formulations for use in cosmetics and skin care products. This article reviews basic mechanisms and possible cosmetic as well as clinical implications of the recent advances in cutaneous vitamin E research. Experimental evidence suggests that topical and oral vitamin E has antitumorigenic, photoprotective, and skin barrier stabilizing properties. While the current use of vitamin E is largely limited to cosmetics, controlled clinical studies for indications such as atopic dermatitis or preventions of photocarcinogenesis are needed to evaluate the clinical benefit of vitamin E.     

肿瘤MUC1/Y的克隆及其胞外段在大肠杆菌中的可溶性表达、纯化和鉴定

为获得MUC1 Y全长cDNA及其胞外段蛋白 ,以用于进一步的生物学功能及肿瘤生物学治疗的研究 .利用RT PCR从HeLa细胞中扩增MUC1 Y全长cDNA ;PCR扩增其胞外段 ,克隆到原核表达载体pGEX 2T ,转化DH5a菌 ,诱导表达 ;亲和层析纯化 ;凝血酶酶切、GST活性及N端蛋白测序鉴定 ;免疫家兔制备多克隆抗体 .所得MUC1 YcDNA的开放读框为 759bp ,登录于GenBank(AF12 552 5) .其信号肽编码序列缺失 9bp ,第 3 3 1位发生G A转换 ,造成缬氨酸突变为蛋氨酸 .表达获得约 4 0kD融合蛋白GST Yex ,占菌体总蛋白 2 5%～ 3 0 % ,其中 70 %～ 80 %为可溶性 ,经亲和层析一步纯化 ,纯度 >90 % ,GST比活性为 0 2 1U μg .凝血酶酶切后的N端蛋白序列测定表明与已知序列完全一致 ,抗血清ELISA效价为 1∶2 50 0 0 0 .结果表明 ,克隆到发生碱基缺失和突变的MUC1 Y全长cDNA ,获得MUC1 Y胞外段蛋白及其多抗 ,可进一步用于相关研究 .     

The potential role of humans in structuring the wooded landscapes of Mesolithic Ireland: a review of data and discussion of approaches

This paper has two primary aims. Firstly, we review new data demonstrating interactions between people, plants, animals and woodlands in Mesolithic Ireland (ca. 8000–4000 cal. b.c.). This includes a synthesis of evidence from archaeological fishtraps, plant macrofossils, palynological indications of disturbance, and large mammal records. Secondly, we suggest that the potential role of humans in structuring the wooded landscape of the island of Ireland has been underestimated and is a key area for future research; Ireland may be an important case study for understanding the role of hunter-gatherers in influencing ecological relationships at the landscape scale. The new data demonstrate that existing models of the role of humans in structuring the wooded landscapes of Ireland are inadequate, and we suggest that new models are required.     

Factors contributing to discrepancies in population monitoring studies

A review of the scientific literature on population monitoring studies (on non-accidentally exposed populations) frequently show that many of these studies using similarly exposed populations and the same laboratory techniques do not produce consistent results. To illustrate the problem, a brief review of studies using well validated techniques (chromosome aberrations and hprt gene mutation) to elucidate genotoxic effects of cigarette smoking is presented. Although many factors can contribute to the generation of discrepant results, two obvious factors are small sample sizes and inadequate experimental data. In addition, a new factor on genetic susceptibility should be considered in population studies whenever appropriate. The new factor is based on recent data showing the influence of polymorphic metabolizing genes on response to environmental mutagens towards biological effects and disease outcome. The common ones include the cytochrome P450 and the glutathione S-transferase genes. The inclusion of susceptibility factors in population monitoring may revolutionize the approach for health risk assessment and for environmental regulations.     

Sandwich enzyme-linked immunosorbent assay of rat apolipoprotein E

A sandwich ELISA for rat apo E was developed. Blood was drawn from rats that had been administered with triamcinolone diacetate to increase apo E-rich HDL in serum. Apo E was purified from the d less than 1.225 g/ml lipoproteins, and antiserum was raised in rabbits. Diluted samples and standards were added into the wells of polystyrene microtiter plates precoated with immunoaffinity-purified IgG and incubated for 90 min. After washing, immunoaffinity-purified Fab'-horseradish peroxidase conjugate was added to each well and incubated for 90 min. The bound enzyme was assayed by a colorimetric method. Samples and standards were pretreated with 6 M guanidine. HCl to maximize the antigenic response of apo E. The sensitivity lies around 1 pg apo E, and the working range was 0.1 to 1.0 ng. All assay procedures were completed within 4-5 hr. The mean intra- and interassay coefficients of variation were 1.8 and 4.1%, respectively. Serum apo E concentrations were 21.2 +/- 2.1 and 61.3 +/- 17.0 mg/dl (mean +/- SD) for young (8-12 weeks old, n = 9) and old (36-40 weeks old, n = 16) rats, respectively. As determined by gel filtrations, most of the apo E in fasted rat serum was associated with larger HDL particles (or HDL1) and a small portion of apo E was present in a free form.     

The Identification and Revision on the Type of Cochleariopsis Y. E. Zhang (Cruciferae)

The genus Cochleariopsis Y.H. Zhang was described in 1985, with C. zhejiangensis Y. H. Zhang, the only member of the genus, as its type. However, this species had been published by O.E. Schulz earlier in 1923, named Cochlearia warburgii O.E. Schulz. Hence, this species is not new one, and the type of the ge-nus should be Cochleariopsis warburgii (O. E. Schulz)L. L. Lu .     

Chronorhythms of the Circulating Erythrocytes and Leukocytes—Correlation with the E.S.R. Cycles

2750 healthy and fasting subjects, 20-30 years old, were studied over a half-year period in 1980. Considering the mean day value as a basic piece of information for statistics, the Erythrocyte Sedimentation Rate (E.S.R.) and the blood counts (erythrocytes, leukocytes, polymorphonuclears, lymphocytes, monocytes and eosinophils) were compared.

The timeless relation between E.S.R. and each cell type number or percentage is rectilinear. The stronger slope and relation apply to the polymorphonuclears (PMN) or to the overall leukocytes.

The chronological normalized variations of the E.S.R. and of the PMN or leukocyte number or percentage are highly correlated. E.S.R. is less correlated with monocytes, eosinophils and Lymphocytes. Contrary to what could have been expected, the erythrocyte situation is but an intermediate one.

The spectra derived from the time variations show that all the cell types, whatever they are, are to be taken into account to explain the E.S.R. value and variation with time, even if, for a given cell type, the correlation and timeless relation were but faint ones.

Each cell type has a specific spectrum. Erythrocytes are subject to low frequency variations (316-158 days). PMNs oscillate with time within the medium frequency range (90 days). Lymphocytes, monocytes and eosinophils fluctuate more quickly (53 days).