Production of a base population and its responses to F-1 selection in the bay scallop, Argopecten irradians irradians Lamarck (1819)

A base population of the bay scallop, Argopecten irradians irradians Lamarck, was produced by crossing two cultured bay scallop populations. After 1 year of rearing, the top 10% truncation selection of the top 10% (i=1.755) was carried out in the base population of about 1300 adults. A control parental group with a an identical number to the select parental group was randomly selected from the entire population before isolation of the select parental group. The result showed that, at the larval stage, the growth rate of larvae in the selected line was significantly higher than that of the control (P < 0.05), and that the genetic gain was 6.78%. Owing to the lower density of control at the spat stage, the mean shell length of the control line was larger than that of the select line at day 100. When the same density was adjusted between two lines in the grow-out stage (from day 100 to 160), the daily growth rate of the selected line was significantly higher than that of the control line (P < 0.05). Survival of the select line was significantly larger than that of the control line in the grow-out stage. In conclusion, the results obtained from this experiment indicate that selective breeding from a base population with a high genetic diversity established by mass spawning between different populations appears to be a promising method of genetic improvement in bay scallop, A. irradians irradians Lamarck.

Different responses to selection in two stocks of the bay scallop, Argopecten irradians irradians Lamarck (1819)

Two different stocks (A and B) of the bay scallop Argopecten irradialls irradians (Lamarck, 1819) were used to test mass selection on growth. Stock A was a descending stock from the initial introduction from U.S.A. in 1982, which had been cultured in China for about 20 years. Stock B was the third generation from a recent introduction from U.S.A. in 1999. Truncation selection was conducted by selecting the largest 11% scallops in shell length from Stock A and the largest 12.7% scallops from Stock B as parents for the respective selected groups. Before the removal of parents for truncation selection, equal numbers of scallops were randomly chosen from Stock A and B to serve as parents for the control groups. Offspring from the four groups were reared under the same hatchery, nursery, and grow-out conditions. Values of response to selection and realized heritability at larvae, spat and grow-out stages for Stock B were all significantly (P < 0.001) higher than its counterpart for Stock A. For Stock A, no significant response to selection was observed (P > 0.05) at any stage, and the realized heritability for shell length was 0.015 +/- 0.024 for larvae, 0.040 +/- 0.027 for spat, and 0.080 +/- 0.009 for grow-out, respectively. For Stock B, however, significant (P < 0.05) response to selection was observed, and the realized heritability for shell length was 0.511 +/- 0.010 for larvae, 0.341 +/- 0.022 for spat, and 0.338 +/- 0.015 for grow-out. On average, responses to selection at the three stages for Stock B was 30 x, 7.1 x, and 3 x higher than its counterpart for Stock A, respectively. Accordingly, realized heritability at above stages for Stock B was 33 X, 7.5 x, and 3.2 X higher than its counterpart for Stock A, respectively. Differences in response to selection and realized heritability between the two stocks are presumably due to differences in genetic variability. As the 20th generation from the initial introduction consisted of only 26 scallops, Stock A is known to be highly inbred, while inbreeding in Stock B is negligible. (C) 2004 Elsevier B.V. All rights reserved.

Vegetation Responses to A Long-term Grazing Intensity Experiment in Alpine Shrub Grassland on Qinghai-Tibet Plateau

在青藏高原中国科学院海北高寒草甸生态系统定位研究站对金露梅高寒灌丛草场植被开展了长期不同放 牧强度试验,分别在短期(4 年) 、中期(11 年) 和长期(18 年) 放牧阶段研究不同放牧干扰强度对草地植物物种多样 性、群落结构、地上生物量和草场质量的影响。研究表明,在不同放牧阶段,随着放牧强度增加植物群落的高度和 盖度都降低。在中期放牧干扰阶段,物种多样性指数和均匀度指数随着放牧强度增加呈现典型的单峰曲线模式; 在长期放牧干扰阶段,随着放牧强度增加,占优势地位的灌木和禾草被典型杂类草替代,其中的重度放牧干扰简化 了高寒灌丛植被群落结构,减少了地上现存生物量,特别是可食优良牧草生物量。植被对放牧的响应除了与放牧 强度和放牧时间阶段密切相关外,还与该地区水热条件的变化有一定的相关性。针对长期放牧干扰的反应特性可 将金露梅灌丛草场中植物划分为增加型、敏感型、忍耐型和无反应型4 种类型。除了丰富度指数、多样性指数和均 匀度指数外,其它一些特征参数并不支持著名的中度干扰假说。本研究发现,长期重度放牧促进了青藏高原高寒 草地退化,适度放牧有利于高寒灌丛草场的生物多样性保护和牧草利用;“取半留半”的放牧原则在青藏高原草场 放牧管理实践中值得推荐,它将有利于防止草场退化,提高牧草利用率和维持较高的生物多样性。

Population dynamics and responses to management of plateau pikas Ochotona curzoniae

1. Plateau pikas Ochotona curzoniae are considered a pest species on the Tibetan Plateau because they compete with livestock for forage and their burrowing could contribute to soil erosion. The effectiveness of pest control programmes in Tibet has not been measured, and it is not known whether changes in livestock management have exacerbated problems with plateau pikas or compromised their control. This study measured the impact of control programmes and livestock management for forage conservation on populations of plateau pikas in alpine meadow in Naqu District, central Tibet, during 2004 and 2005.2. Current techniques for controlling plateau pikas in spring cause large reductions in abundance, but high density-dependent rates of increase result in no differences between treated and untreated populations by the following autumn. Rates of increase from spring to autumn are not influenced by standing plant biomass or concurrent grazing by yaks Bos grunniens and Tibetan sheep Ovis aries.3. In autumn there was significantly lower biomass outside fenced areas with year-round livestock grazing compared with inside fenced areas with equivalent or higher numbers of plateau pikas but predominantly winter grazing by livestock. Inside fenced areas, control of plateau pikas in spring produced no detectable effect on standing plant biomass at the end of the following summer compared with uncontrolled populations of plateau pikas.4. Regardless of their initial density, populations of plateau pikas declined rapidly over winter outside fenced areas where there was very low standing plant biomass in autumn. However, inside fenced areas with higher plant biomass in autumn, low-density populations of plateau pikas declined more slowly than high-density populations.5. Synthesis and applications. Current control programmes have limited effect because populations of plateau pikas can recover in one breeding season. There was no apparent increase in forage production in areas where plateau pikas were controlled. However, plateau pikas appear to benefit from changes in grazing management, with low-density populations declining less over winter inside fenced areas than elsewhere. It was not evident that control programmes are warranted or that they will improve the livelihoods of Tibetan herders.

Dynamic and complex microclimate responses to warming and grazing manipulations

Synthesis efforts that identify patterns of ecosystem response to a suite of warming manipulations can make important contributions to climate change science. However, cross-study comparisons are impeded by the paucity of detailed analyses of how passive warming and other manipulations affect microclimate. Here we document the independent and combined effects of a common passive warming manipulation, open-top chambers (OTCs), and a simulated widespread land use, clipping, on microclimate on the Tibetan Plateau. OTCs consistently elevated growing season averaged mean daily air temperature by 1.0-2.0 degrees C, maximum daily air temperature by 2.1-7.3 degrees C and the diurnal air temperature range by 1.9-6.5 degrees C, with mixed effects on minimum daily air temperature, and mean daily soil temperature and moisture. These OTC effects on microclimate differ from reported effects of a common active warming method, infrared heating, which has more consistent effects on soil than on air temperature. There were significant interannual and intragrowing season differences in OTC effects on microclimate. For example, while OTCs had mixed effects on growing season averaged soil temperatures, OTCs consistently elevated soil temperature by approximately 1.0 degrees C early in the growing season. Nonadditive interactions between OTCs and clipping were also present: OTCs in clipped plots generally elevated air and soil temperatures more than OTCs in nonclipped plots. Moreover, site factors dynamically interacted with microclimate and with the efficacy of the OTC manipulations.These findings highlight the need to understand differential microclimate effects between warming methods, within warming method across ecosystem sites, within warming method crossed with other treatments, and within sites over various timescales. Methods, sites and scales are potential explanatory variables and covariables in climate warming experiments. Consideration of this variability among and between experimental warming studies will lead to greater understanding and better prediction of ecosystem response to anthropogenic climate warming.

The lack of associations between alleles at the hypoxia-Inducible factor 1A C1772T loci and responses to acute hypoxia.

Objective The aim of this study was to investigate the associations between alleles of the hypoxia-inducible factor 1A (HIF1A) C1772T polymorphism and several physiological responses to hypoxia, including the hypoxic ventilatory response (HVR), and serum erythropoietin (EPO), arterial oxygen saturation (Sao2), and acute mountain sickness (AMS) responses during 8 hours of exposure to normobaric hypoxia. Methods A total of 76 males participated in the study; 52 participants completed an 8-hour exposure to 12.7% oxygen, during which time Sao2, EPO concentrations, and AMS scores were measured, while 62 individuals took part in an HVR trial (in total 38 individuals completed both protocols). DNA was obtained from leukocytes, and a 346-bp fragment of the HIF1A gene containing the C1772T polymorphism was amplified using polymerase chain reaction. Fragments were sequenced to reveal individual genotypes, and the associations between HIF1A genotype and EPO, Sao2, AMS responses to hypoxia and HVR were examined. Results The magnitude of the hypoxic responses was highly variable between individuals. The increase in participants' EPO responses ranged from 89% to 388% of baseline values following hypoxia, while Sao2 values during the exposure ranged from 71% to 89%. The HVR ranged from −0.04 to +2.18 L · min−1 · Sao2%−1 among participants. No significant differences in EPO, Sao2, AMS, or HVR results were observed between the HIF1A CC genotype and the combined CT/TT genotype group. Conclusion In this study, the HIF1A C1772T polymorphism does not appear to influence EPO, Sao2, or AMS responses during acute hypoxic exposure, or the magnitude of the HVR.

The effect of 2 weeks vitamin C supplementation on immunoendocrine responses to 2.5 h cycling exercise in man

Davison G, Gleeson M, 2006. The effect of 2 weeks vitamin C supplementation on immunoendocrine responses to 2.5 h cycling exercise in man. European Journal of Applied Physiology 97(4): 454-461 RAE2008

Antioxidant supplementation and immunoendocrine responses to prolonged exercise

Davison, Glen, et al., 'Antioxidant supplementation and immunoendocrine responses to prolonged exercise', Medicine and Science in Sports and Exercise, (2007) 39(4) pp.645-652 RAE2008

Maximal strength and cortisol responses to psyching-up during the squat exercise

McGuigan, M. R., Ghiagiarelli, J., Tod, D. (2005). Maximal strength and cortisol responses to psyching-up during the squat exercise. Journal of Sports Sciences, 23 (7), 687-692. RAE2008

Influence of acute vitamin C and/or carbohydrate ingestion on hormonal, cytokine, and immune responses to prolonged exercise

Davison, G. and Gleeson, M. (2005). Influence of Acute Vitamin C and/or Carbohydrate Ingestion on Hormonal, Cytokine, and Immune Responses to Prolonged Exercise. International Journal of Sport Nutrition and Exercise Metabolism. 15(5), pp.465-479 RAE2008

Customers' responses to retail brand extensions

Alexander, N.; and Colgate, N. (2005). Customers' responses to retail brand extensions. Journal of Marketing Management. 21(3-4), pp.393-419 RAE2008

CD4+ CD25+ regulatory T cells control T helper cell type 1 responses to foreign antigens induced by mature dendritic cells in vivo.

Recent evidence suggests that in addition to their well known stimulatory properties, dendritic cells (DCs) may play a major role in peripheral tolerance. It is still unclear whether a distinct subtype or activation status of DC exists that promotes the differentiation of suppressor rather than effector T cells from naive precursors. In this work, we tested whether the naturally occurring CD4+ CD25+ regulatory T cells (Treg) may control immune responses induced by DCs in vivo. We characterized the immune response induced by adoptive transfer of antigen-pulsed mature DCs into mice depleted or not of CD25+ cells. We found that the development of major histocompatibility complex class I and II-restricted interferon gamma-producing cells was consistently enhanced in the absence of Treg. By contrast, T helper cell (Th)2 priming was down-regulated in the same conditions. This regulation was independent of interleukin 10 production by DCs. Of note, splenic DCs incubated in vitro with Toll-like receptor ligands (lipopolysaccharide or CpG) activated immune responses that remained sensitive to Treg function. Our data further show that mature DCs induced higher cytotoxic activity in CD25-depleted recipients as compared with untreated hosts. We conclude that Treg naturally exert a negative feedback mechanism on Th1-type responses induced by mature DCs in vivo.

Identification of major factors influencing ELISpot-based monitoring of cellular responses to antigens from Mycobacterium tuberculosis.

A number of different interferon-gamma ELISpot protocols are in use in laboratories studying antigen-specific immune responses. It is therefore unclear how results from different assays compare, and what factors most significantly influence assay outcome. One such difference is that some laboratories use a short in vitro stimulation period of cells before they are transferred to the ELISpot plate; this is commonly done in the case of frozen cells, in order to enhance assay sensitivity. Other differences that may be significant include antibody coating of plates, the use of media with or without serum, the serum source and the number of cells added to the wells. The aim of this paper was to identify which components of the different ELISpot protocols influenced assay sensitivity and inter-laboratory variation. Four laboratories provided protocols for quantifying numbers of interferon-gamma spot forming cells in human peripheral blood mononuclear cells stimulated with Mycobacterium tuberculosis derived antigens. The differences in the protocols were compared directly. We found that several sources of variation in assay protocols can be eliminated, for example by avoiding serum supplementation and using AIM-V serum free medium. In addition, the number of cells added to ELISpot wells should also be standardised. Importantly, delays in peripheral blood mononuclear cell processing before stimulation had a marked effect on the number of detectable spot forming cells; processing delay thus should be minimised as well as standardised. Finally, a pre-stimulation culture period improved the sensitivity of the assay, however this effect may be both antigen and donor dependent. In conclusion, small differences in ELISpot protocols in routine use can affect the results obtained and care should be given to conditions selected for use in a given study. A pre-stimulation step may improve the sensitivity of the assay, particularly when cells have been previously frozen.

The protective role of religious coping in adolescents' responses to poverty and sexual decision-making in rural Kenya.

In this study, we explored how adolescents in rural Kenya apply religious coping in sexual decision-making in the context of high rates of poverty and Human Immunodeficiency Virus (HIV). Semi-structured interviews were conducted with 34 adolescents. One-third (13) reported religious coping related to economic stress, HIV, or sexual decision-making; the majority (29) reported religious coping with these or other stressors. Adolescents reported praying for God to partner with them to engage in positive behaviors, praying for strength to resist unwanted behaviors, and passive strategies characterized by waiting for God to provide resources or protection from HIV. Adolescents in Sub-Saharan Africa may benefit from HIV prevention interventions that integrate and build upon their use of religious coping.