Contrasting effects of T cell growth factors on T cell responses to melanoma in vitro

 Determinants of T cell responses to tumor cells remain largely unknown. In the present study we have used long-term cultures of human melanoma cells and autologous peripheral blood lymphocytes to examine the influence of cytokines with T cell growth activity on the phenotype and cytotoxic and proliferative response of T cells to melanoma. It was found that addition of interleukin-4 (IL-4) inhibited the response of CD8⁺ T cells and promoted the response of the CD4 subset. IL-2 or IL-7 was effective in increasing melanoma-specific cytotoxic T lymphocyte (CTL) activity in cultures where CD8 T cells were predominant, whereas IL-4 followed by IL-2 was most effective in cultures where CD4 T cells predominated. IL-10 or IL-12 inhibited proliferation and CTL activity against melanoma in long-term cultures. The effects of IL-12 were reproduced in long-term cultures of T cells stimulated with mAb against CD3 and were shown to depend on prior exposure of T cells to IL-12 before IL-2. As yet unidentified factors, such as co-factor expression on melanoma, appear to be as important as exogenous cytokines in determining the nature of T cell responses to melanoma. These results suggest that analysis of responses in long-term culture may assist in defining the role of key cytokines and other determinants of immune responses to melanoma. Received: 4 June 1996 / Accepted: 12 November 1996     

Production of TNFα and IL-6 by Activated Whole Blood from HIV-1 Infected Patients Detected by a One-Stage Procedure: Relationship with the Phenotype of HIV-1 Isolates

Diluted whole blood (WB) culturing may be the most appropriate milieu in which to study cytokine production in vitro. We tested TNFα and IL-6 production using small volumes of WB (25 μl) from HIV-1 positive patients with a one-step procedure that combines WB stimulation with LPS, PHA and cytokine measurement. We studied 49 patients without secondary infection or at distance of secondary infection staged according to the 1993 classification of the CDC and 12 healthy seronegative subjects. Heparinized blood from 5 control subjects had been collected sequentially during a period of 5 months. The individual variations of TNFα and IL-6 production were limited for all these individuals. In 1 out of 20 CDC group A patients, 6 out of 17 CDC group B patients and 3 out of 12 CDC group C patients, we obtained higher values of TNFα than the mean + 2 S.D. of the control group. In 3 out of 20 CDC group A patients, 1 out of 17 CDC group B patients without AIDS and 5 out of 12 CDC group C patients, the TNFα values were lower than the mean ?2 S.D. of the control group. Low IL-6 values were obtained in 1 out of 20 CDC group A patients and 1 out of 17 CDC group B patients and 3 out of 12 CDC group C patients. There was no correlation between TNFα production in vitro and plasma level of TNFα. We found no correlation between the levels of cytokines and monocyte count or between the levels of cytokines and CD4 T-cell count in peripheral blood. Our data point out a disarray in TNFα and IL-6 production by WB from HIV-1 infected patients. The relationship between the disarray of cytokine production and cytopathogenicity of HIV-1 isolates in the P4 cell line was investigated in this study. We found a correlation between the high level of TNFα produced by WB and the phenotype of HIV-1 isolates isolated from patients. The one-stage procedure used in this work is of potential value to investigate the activation status of cells for monitoring HIV-1 positive individuals and predicting HIV-1 phenotype.     

缺氧对体外培养的肺动脉平滑肌细胞形态及增殖的影响

本实验应用形态学、免疫组化染色,＾３Ｈ－ＴｄＲ掺入、流式细胞等技术探讨缺氧（〈１％Ｏ２和２．５％Ｏ２）对肺动脉平滑肌细胞（ＰＡＳＭ）形态及增殖的影响。结果表明：缺氧２４ｈ使ＰＡＳＭ表型从收缩型向合成型转换,胞浆内ＳＭ－ａ ａｃｔｉｎ减少,线粒体和粗面内质网增多,缺氧４８ｈ以后线粒体肿胀,空泡化,内质网扩张,胞浆内出现髓鞘样结构。流式细胞分析显示缺氧ＰＡＳＭ Ｇ２／Ｍ期细胞比例明显增多（Ｐ〈０．００     

Selection often overrides the effects of random processes in island populations of Philaenus spumarius (Homoptera)

The influence of various evolutionary factors on the populations of the colour polymorphic meadow spittlebug, Philaenus spumarius (Homoptera), was investigated on islands in the Gulf of Finland. Long-term (30-year) investigations showed that the populations can survive through very narrow bottlenecks, but after strong reduction in the size of a population, random genetic drift may remove alleles or change allele frequencies. One of the factors sustaining the presence of almost all the colour polymorphism alleles in almost all the populations is gene flow. Migration seems to be largely by air and by the sea surface (anemohydrochoric). On one rocky island, gene flow was able to carry the top dominant allele, p^T, to a number of scattered plant stands. However, it was not powerful enough to alter the differences in allele frequencies between populations living on the same island in meadows of different types 3 m or 12 m from each other. It is highly probable that the factor operating is meadow-specific selection. Its action appears to be based on the ecological character of the meadow. In the different meadows, the coverages of the food plants of the spittlebug are dissimilar. Differences in plant assemblages are possibly of importance in maintaining the meadow-specific allele frequencies in the spittlebug populations.     

SEASONAL GROWTH AND PHENOTYPIC VARIATION IN PORPHYRA LINEARIS (RHODOPHYTA) POPULATIONS ON THE WEST COAST OF IRELAND1

The phenology and seasonal growth of Porphyra linearis Grev. were investigated in two morphologically dissimilar populations from the west coast of Ireland. Thallus size and reproductive status of individuals were monitored monthly between June 1997 and June 1998. Both populations exhibited a similar phenology: gametophyte stages appeared on the shore in October, with spermatangial and zygotosporangial sori appearing the following February; the gametophyte stage began to degenerate in April and had disappeared completely by June. However, significant differences in growth and reproduction in the field and in cultures of plants from the two populations were observed. Thallus length and width of individuals from one population were significantly longer throughout the sample period, and reproduction and sporulation occurred 1 month earlier. Also, in situ relative growth rates (RGRs) of plants differed significantly and were correlated with different climatic factors (sunshine, day length, irradiance, rainfall, seawater temperature, and intertidal temperatures), suggesting that plants were affected by two different microhabitats. At one site, blades were more exposed to wave action, sunshine, and extreme minimum temperatures, while at the other site, blades were more protected in winter, spring, and early summer. In culture, RGRs of blades from the second site were higher than RGRs of blades from the first site under short days, corroborating the field results and suggesting a degree of phenotypic differentiation between the two populations. However, there were no sequence divergences of the RUBISCO spacer between strains of the two P. linearis populations.     

在全基因组范围内筛选酵母中砷抗性相关基因

砷化物是广泛应用的抗癌药物,特别是对白血病有显著疗效.然而,治疗过程中病人会因对砷化物具有耐药性而影响治疗效果,而目前对于砷抗性机制尚缺全面深入的研究.利用酵母作为模式生物,使用不同浓度的砷对由4757个酵母缺失型突变体组成的菌株库进行筛查.共鉴定出104个基因/开放阅读框(ORF),其缺失导致酵母对砷的抗性增加.生物信息学分析结果提示,这些基因与mRNA分解代谢、应激反应、组蛋白乙酰化和蛋白质合成及分解代谢等功能有关.同时这些基因中多于半数具有哺乳动物同源类似物.所以,进一步研究这些基因有望为人类砷化物的耐药性及毒性机制研究提供富有价值的新线索.     

Body pigmentation pattern to assess introgression by hatchery stocks in native Salmo trutta from Mediterranean streams

Five qualitative and seven quantitative colouration and spotting pattern features were measured in 23 brown trout Salmo trutta populations and two hatchery stocks. Simultaneously, the LDH‐C1 *, a diagnostic locus fixed for *90 and *100 alleles in stocking and native populations from southern Europe, respectively, was analysed to classify the brown trout studied according to their origin: native, hatchery stock and hybrids. The three genotypes showed significant differences in the colouration and spotting features and a discriminant function analysis could correctly identify 79% of the individuals. The most discriminating variables were dorsal fin margin colour, number of opercular spots, presence of the preopercular mark and diameter of black spots. Given the low cost, ease and possibility of field identification of native fish, the results indicate great opportunities for the application of morphological‐based classification models on the conservation and management of native brown trout stocks.     

The ecology of an adaptive radiation of three‐spined stickleback from North Uist,Scotland

There has been a large focus on the genetics of traits involved in adaptation, but knowledge of the environmental variables leading to adaptive changes is surprisingly poor. Combined use of environmental data with morphological and genomic data should allow us to understand the extent to which patterns of phenotypic and genetic diversity within a species can be explained by the structure of the environment. Here, we analyse the variation of populations of three‐spined stickleback from 27 freshwater lakes on North Uist, Scotland, that vary greatly in their environment, to understand how environmental and genetic constraints contribute to phenotypic divergence. We collected 35 individuals per population and 30 abiotic and biotic environmental parameters to characterize variation across lakes and analyse phenotype–environment associations. Additionally, we used RAD sequencing to estimate the genetic relationships among a subset of these populations. We found a large amount of phenotypic variation among populations, most prominently in armour and spine traits. Despite large variation in the abiotic environment, namely in ion composition, depth and dissolved organic Carbon, more phenotypic variation was explained by the biotic variables (presence of predators and density of predator and competitors), than by associated abiotic variables. Genetic structure among populations was partly geographic, with closer populations being more similar. Altogether, our results suggest that differences in body shape among stickleback populations are the result of both canalized genetic and plastic responses to environmental factors, which shape fish morphology in a predictable direction regardless of their genetic starting point.     

The social and ecological costs of an ‘over-extended' phenotype

Extended phenotypes offer a unique opportunity to experimentally manipulate and identify sources of selection acting on traits under natural conditions. The social cichlid fish Neolamprologus multifasciatus builds nests by digging up aquatic snail shells, creating an extended sexual phenotype that is highly amenable to experimental manipulation through addition of extra shells. Here, we find sources of both positive sexual selection and opposing natural selection acting on this trait; augmenting shell nests increases access to mates, but also increases social aggression and predation risk. Increasing the attractiveness of one male also changed social interactions throughout the social network and altered the entire community structure. Manipulated males produced and received more displays from neighbouring females, who also joined augmented male territories at higher rates than unmanipulated groups. However, males in more attractive territories received more aggression from neighbouring males, potentially as a form of social policing. We also detected a significant ecological cost of the ‘over-extended'' phenotype; heterospecific predators usurped augmented nests at higher rates, using them as breeding sites and displacing residents. Using these natural experiments, we find that both social and ecological interactions generate clear sources of selection mediating the expression of an extended phenotype in the wild.