Modeling effects of environmental change on wolf population dynamics, trait evolution, and life history

Environmental change has been observed to generate simultaneous responses in population dynamics, life history, gene frequencies, and morphology in a number of species. But how common are such eco-evolutionary responses to environmental change likely to be? Are they inevitable, or do they require a specific type of change? Can we accurately predict eco-evolutionary responses? We address these questions using theory and data from the study of Yellowstone wolves. We show that environmental change is expected to generate eco-evolutionary change, that changes in the average environment will affect wolves to a greater extent than changes in how variable it is, and that accurate prediction of the consequences of environmental change will probably prove elusive.     

Spectroscopic evidence of metabolic control

The Pasteur and Crabtree effects demonstrate that changes at the beginning of the metabolic sequence for glucose metabolism give rise to effects at the end, and vice versa. We have presented here three additional responses of the ascites tumor cell suspensions, and presumably more will be uncovered. Each one of these responses is a manifestation of factors in the underlying mechanism that are in the nature of chemical feedback of a linear or nonlinear nature. The metabolic reactions are sufficiently complex that it is unlikely that any single component or step need control metabolism in different types of cells or under all conditions for a particular cell. However, it is due to a favorable circumstance that, in an appropriate type of cell and with the use of a direct intracellular indicator for changes in ADP concentration, we can state that the respiratory metabolism of the ascites tumor cell suspension, as freshly withdrawn from the mouse abdomen, is limited by the intracellular ADP concentration, and that this is why these cells show a predominance of glycolytic over respiratory activity. The response of the metabolism to small and large additions of glucose illustrates aspects of the metabolic mechanism which involve control of endogenous metabolism and compartmentalization of ATP formed in oxidative phosphorylation, the net result being a depression of the respiratory activity. The results of this approach emphasize the importance of chemical assays of localized portions of the living cell in its physiological state (61).     

Omethoate-Induced Changes of (+)-δ-Cadinene Synthase Activity and Gossypol Content in Cotton Seedlings

The gene expression and activity of (+)-δ-cadinene synthase during cotton development and in response to stress, as well as the spatial and temporal pattern of sesquiterpene biosynthesis, constitute one of chemical defense mechanisms in cotton plants. In order to explore the effects of omethoate on the cotton defense in relation to (+)-δ-cadinene synthase and gossypol, effects of omethoate treatments on activity of (+)-δ-cadinene synthase and gossypol content in cotton seedlings were investigated. Cotton seedlings treated with 400 mg L⁻¹ omethoate exhibited a significant decrease in the specific activity of (+)-δ-cadinene synthase from 12 to 120 h after treating when compared to the untreated control; significantly lower (+)-δ-cadinene synthase activity was also observed in cotton seedlings treated with 200 mg L⁻¹ omethoate from 72 to 120 h after treating; but for cotton seedlings treated with 100 mg L⁻¹ omethoate, from 12 to 120 h after treating, no significant changes were observed for activity of (+)-δ-cadinene synthase. The gossypol content in cotton seedlings treated with 100, 200 or 400 mg L⁻¹ omethoate for different time periods showed no significant changes compared to that of the control. These results indicated that the activity of (+)-δ-cadinene synthase in cotton seedlings in responses to exposure of omethoate at three concentrations for different time periods followed dose- and time-dependent responses to omethoate exposure. With omethoate as a chemical stress factor for cotton seedlings, the cotton defense in relation to the activity of (+)-δ-cadinene synthase in cotton seedlings may be affected by omethoate application.     

The alarmin interleukin-33 drives protective antiviral CD8⁺ T cell responses

Pathogen-associated molecular patterns decisively influence antiviral immune responses, whereas the contribution of endogenous signals of tissue damage, also known as damage-associated molecular patterns or alarmins, remains ill defined. We show that interleukin-33 (IL-33), an alarmin released from necrotic cells, is necessary for potent CD8(+) T cell (CTL) responses to replicating, prototypic RNA and DNA viruses in mice. IL-33 signaled through its receptor on activated CTLs, enhanced clonal expansion in a CTL-intrinsic fashion, determined plurifunctional effector cell differentiation, and was necessary for virus control. Moreover, recombinant IL-33 augmented vaccine-induced CTL responses. Radio-resistant cells of the splenic T cell zone produced IL-33, and efficient CTL responses required IL-33 from radio-resistant cells but not from hematopoietic cells. Thus, alarmin release by radio-resistant cells orchestrates protective antiviral CTL responses.     

Crystal structure of the human K2P TRAAK, a lipid- and mechano-sensitive K+ ion channel

TRAAK channels, members of the two-pore domain K(+) (potassium ion) channel family K2P, are expressed almost exclusively in the nervous system and control the resting membrane potential. Their gating is sensitive to polyunsaturated fatty acids, mechanical deformation of the membrane, and temperature changes. Physiologically, these channels appear to control the noxious input threshold for temperature and pressure sensitivity in dorsal root ganglia neurons. We present the crystal structure of human TRAAK at a resolution of 3.8 angstroms. The channel comprises two protomers, each containing two distinct pore domains, which create a two-fold symmetric K(+) channel. The extracellular surface features a helical cap, 35 angstroms tall, that creates a bifurcated pore entryway and accounts for the insensitivity of two-pore domain K(+) channels to inhibitory toxins. Two diagonally opposed gate-forming inner helices form membrane-interacting structures that may underlie this channel's sensitivity to chemical and mechanical properties of the cell membrane.     

University-Industry Interaction Patterns: Past models are analyzed, some recent experiments described, and recommendations for the future given

The nation is entering a period when the R & D output must be increased, probably without major increases in resource allocation. Obviously, in this situation, either efficiency or productivity must be increased. Perhaps one of the most wasteful aspects of the national R & D system (and one that received little attention during the golden era of the 15 percent per year expansion) has been the very weak coupling between the university, on the one hand, and industry (or government), on the other. It is a serious error to allege about such coupling that "it has never worked," that the objectives and reward structures of the institutions are such that it cannot work, and so on. The fact is that coupling has never been tried seriously. History shows that the total dollar effort in research that required coupling or that had coupling as its main objective was on the order of $10 million per year (that is, much less than 0.1 percent of the research money spent on U.S. campuses). At the same time, there is little doubt that the experiments which must and will be tried in the immediate future call for innovations in management and changes in the attitude and structure of many universities. In conversations with administrators who have had experience with such programs, I have found strong suggestions of very mixed responses from the universities. In light of these responses, and if effectiveness is a goal, it would be better for those universities that are more wedded to disciplinary research, to single principal-investigator work, not to participate in these new efforts. We need much greater diversity in the styles of university life, and it would be healthy for the academic enterprise if some universities retained a greater degree of detachment from society, while others consciously decided to interact more with it, through the private sector, and made the changes necessary to do so. If initial funding is restricted to those universities that consider university-industry or university-government research a worthy objective and that have a proven track record and a favorable administrative and reward structure, the new programs may well establish a major new pattern of national R & D.     

The Toll-like receptor 2 pathway establishes colonization by a commensal of the human microbiota

Mucosal surfaces constantly encounter microbes. Toll-like receptors (TLRs) mediate recognition of microbial patterns to eliminate pathogens. By contrast, we demonstrate that the prominent gut commensal Bacteroides fragilis activates the TLR pathway to establish host-microbial symbiosis. TLR2 on CD4(+) T cells is required for B. fragilis colonization of a unique mucosal niche in mice during homeostasis. A symbiosis factor (PSA, polysaccharide A) of B. fragilis signals through TLR2 directly on Foxp3(+) regulatory T cells to promote immunologic tolerance. B. fragilis lacking PSA is unable to restrain T helper 17 cell responses and is defective in niche-specific mucosal colonization. Therefore, commensal bacteria exploit the TLR pathway to actively suppress immunity. We propose that the immune system can discriminate between pathogens and the microbiota through recognition of symbiotic bacterial molecules in a process that engenders commensal colonization.     

Potassium ion release and enzyme secretion: adrenergic regulation by alpha- and beta-receptors

Epinephrine caused amylase secretion and K(+) release in rat parotid slices. Propranolol, which blocks beta-receptors, inhibited amylase secretion; phentolamine, which blocks alpha-receptors, inhibited K(+) release. Since enzyme secretion was associated with fusion of secretory granules to the cell membrane and K(+) release was associated with vacuole formation, it could be shown that both alpha- and beta-receptors are present in the same exocrine cell. The findings appear to exclude cyclic 3',5'-adenosine monophosphate as an intermediate in the alpha-receptor response.     

维生素E和微量元素硒对机体免疫机能的影响

缺乏维生素E(VE)和微量元素硒(Se)都能降低机体的免疫功能。日粮中补充适量的VE或Se使动物对抗原的反应能力加强,高剂量的VE刺激免疫反应增强,高浓度Se则引起机体中毒,抑制免疫功能。 VE和Se有协同作用,活化多种免疫活性细胞,可能主要影响辅助性T细胞。二者共同作用的机制是使生物膜处于还原状态,减少前列腺素的合成,从而加强细胞免疫和体液免疫功能。     

(+)-柠檬烯和3-(+)-蒈烯对不同发育期华山松木蠹象诱捕量的变化

为了进一步验证处于补充营养期和交尾产卵期的华山松木蠹象对来自寄主华山松的(+)-柠檬烯和3-(+)-蒈烯趋向反应存在较大差别,进行了林间诱捕试验。结果表明:在2008年,(+)-柠檬烯的诱捕高峰出现在诱捕初期的4月中旬、下旬;3-(+)-蒈烯的诱捕高峰则出现在诱捕后期的6月上旬、中旬,并且在7月上旬出现一个小高峰;在2009年,(+)-柠檬烯的诱捕高峰出现在4月下旬至5月下旬,3-(+)-蒈烯的诱捕高峰出现在6月下旬至7月中旬,在8月上旬出现一个诱捕小高峰。当以(+)-柠檬烯和3-(+)-蒈烯的1∶3的混合物为引诱剂时,则在5月上旬、5月下旬和7月上旬出现3个诱捕高峰。诱捕结果证实了不同发育期的华山松木蠹象对寄主挥发物具有不同的嗅觉感受能力的推测。     

小菜蛾成虫对十字花科9种植物挥发性物质的触角电生理反应

采用昆虫触角电位测定方法,以十字花科9种植物挥发性物质为对象,研究小菜蛾雌、雄成虫对不同浓度植物挥发性物质的触角电位反应.试验结果表明:六碳醇或六碳醛均能引起较强的EAG反应,如正己醛、反-2-己烯醛、正己醇,而萜烯类化合物如(1R) -(+)-α-蒎烯、α-萜品烯,(+)-3-莰烯、桉树脑和D-柠檬烯激发的EAG相对...     

手性三唑类杀菌剂氟环唑对土壤微生物的立体选择性影响

为了研究土壤微生物对手性三唑类杀菌剂氟环唑的立体选择性响应,通过非靶向代谢组学和高通量测序联合技术探究了土壤代谢组和微生物群落对氟环唑外消旋体及对映体的响应机制。结果表明：氟环唑及其对映体处理4周后,土壤中氟环唑降解不显著,其残留能够引起土壤代谢组和土壤微生物群落组成的显著变化。土壤代谢组、细菌和真菌群落组成、PICRUSt基因功能预测的代谢途径均表现出由2R,3S-（+）-氟环唑驱动的立体选择性响应。PICRUSt基因预测表明,细菌中被显著影响的MetaCyc通路有10条,真菌中比对出22条。氟环唑外消旋体和（+）-对映体比（-）-对映体表现出对土壤微生物更显著的干扰作用（P<0.05）。氟环唑暴露引起了土壤环境中细菌和真菌群落、代谢、基因功能预测通路不同程度的立体选择性响应。鉴于土壤环境在农业生产中的重要性,土壤微生物组和代谢组的表征可以为暴露于手性三唑类农药顺式氟环唑及其对映体所带来的生态风险提供新的见解。     

氮素在枣树中贮藏位置、形态及循环利用研究

红枣作为人们日常生活中的常见水果之一,其有着极高的维生素,并具有滋阴补阳之 功效,这也使其深受人们的青睐与欢迎。现如今,枣树种植已经成为一种重要的农业产业,由于 枣树的生长在很大程度上取决于氮素,因此对枣树中氮素的贮藏位置、形态及其循环利用进行 研究是具有重要意义的,其能够为氮素的施肥提供科学的指导,从而促进枣树生长,提高红枣品 质。鉴于此,本文便对氮素在枣树中的贮藏位置分布、存在形态及循环利用做出深入的研究,以 期能够促进我国枣树种植产业的发展。     

华山松大小蠹对华山松挥发性物质行为反应的研究

以11种华山松挥发物单体和2种不同受害状态的华山松树皮挥发油为材料,利用嗅觉仪测定华山松大小蠹对不同浓度的不同挥发物的行为反应。结果表明:华山松大小蠹雌、雄成虫对(S)-(—)-β-蒎烯表现出趋避反应,而对10种挥发物质单体和不同被害阶段华山松挥发油均表现出趋向反应;在低浓度刺激下,华山松大小蠹雌、雄成虫对α-菲兰烯表现出显著的趋向反应;随着浓度的升高,华山松大小蠹雌性成虫对(S)-(—)-α-蒎烯、(—)-莰烯和α-菲兰烯也表现出明显的趋向反应。而华山松大小蠹雄性成虫则对(R)-(+)-α-蒎烯和3-蒈烯表现出明显的趋向反应;雌虫对α-菲兰烯的趋向反应显著高于(R)-(+)-α-蒎烯、(S)-(—)-α-蒎烯、(—)-莰烯和3-蒈烯,而雄虫对α-菲兰烯和(R)-(+)-α-蒎烯的趋向反应显著大于对(S)-(—)-α-蒎烯、(—)-莰烯和3-蒈烯的反应。同时华山松大小蠹雌虫对(—)-莰烯、健康华山松韧皮部挥发油和被害华山松韧皮部挥发油的行为反应显著大于雄虫。华山松大小蠹对一些华山松挥发物的行为反应具有性别差异性,也对不同种类和浓度挥发物的行为反应存在差异。     

A magnesium current in Paramecium

Recent reappraisals of the role of ionized magnesium in cell function suggest that many cells maintain intracellular free Mg2+ at low concentrations (0.1 to 0.7 mM) and that external agents can influence cell function via changes in intracellular Mg2+ concentration. Depolarization and hyperpolarization of voltage-clamped Paramecium elicited a Mg2(+)-specific current, IMg. Both Co2+ and Mn2+ were able to substitute for Mg2+ as charge carriers, but the resultant currents were reduced compared with Mg2+ currents. Intracellular free Mg2+ concentrations were estimated from the reversal potential of IMg to be about 0.39 mM. The IMg was inhibited when external Ca2+ was removed or a Ca2+ chelator was injected, suggesting that its activation was Ca2(+)-dependent.     

关岭牛MyoD基因家族对MyoD1启动子活性的影响

【目的】生肌决定因子(myogenic determination gene,MyoD)家族是肌肉生成过程中参与分子调控作用的一个重要家族。该家族包括MyoD1,Myf5,MyoG和Myf6,只表达在成熟的骨骼肌细胞和其前期细胞中;在其他的非肌细胞中, MyoD基因家族会被抑制。该家族中,MyoD1负责早期胚胎成肌祖细胞的激活并参与胚后骨骼肌的生长、发育和修复等方面的调节,以维持个体骨骼肌的相对稳定,是启动和维持骨骼肌细胞分化和生长的重要因素,具有尤为重要的作用,已成为研究热点。目前MyoD1在多态性和关联性分析等方面的研究较多,表达调控方面主要是研究小鼠、鸡和猪肌细胞生成机理;在牛上对它的研究主要在转录后和翻译水平的表达情况,但对MyoD1在转录调控方面的作用机制还不明确。文章研究关岭牛MyoD基因家族对MyoD1启动子活性的影响,为探讨牛MyoD1的表达调控机制奠定基础。【方法】通过设计特异性引物克隆关岭牛 MyoD基因家族CDS区和MyoD1启动子片段P1和P2;同时利用双酶切的方法分别将CDS区和克隆的启动子序列连入pcDNA3.1（+）和pGL3-Basic基本骨架,构建真核表达载体pcDNA3.1（+）-Myf5、pcDNA3.1（+）-Myf6、pcDNA3.1（+）-MyoD、pcDNA3.1（+）-MyoG和含萤火虫荧光素酶报告基因的报告载体pGL3-P1、pGL3-P2。重组质粒经酶切和测序鉴定后,利用共转染的方法将真核表达载体和报告载体转染小鼠C2C12细胞,30 h后裂解细胞并检测细胞裂解液的双荧光素酶活性。最后根据荧光素酶的相对活性来分析 MyoD基因家族对MyoD1启动子活性的影响。【结果】克隆得到的关岭牛 MyoD基因家族CDS区和MyoD1启动子序列测序正确,载体pcDNA3.1（+）-Myf5、pcDNA3.1（+）-Myf6、pcDNA3.1（+）-MyoD、pcDNA3.1（+）-MyoG、pGL3-P1和pGL3-P2经酶切和测序鉴定,证实载体构建成功;与相应剂量的对照组相比,转染pcDNA3.1（+）-Myf5、 pcDNA3.1（+）-Myf6、pcDNA3.1（+）-MyoD后,pGL3-P1的相对荧光素酶活性明显增强,其中,在转染量为200 ng时增强作用最强,差异显著(P＜0.05);转染pcDNA3.1（+）-MyoG后,虽然对pGL3-P1的相对荧光素酶活性有增强作用,但差异不显著(P＞0.05);而转染pcDNA3.1（+）-Myf5、 pcDNA3.1（+）-Myf6、pcDNA3.1（+）-MyoD、pcDNA3.1（+）-MyoG后,pGL3-P2的相对荧光素酶活性变化不明显 (P＞0.05)。【结论】在小鼠C2C12细胞中外源过表达转录因子MyoD、Myf5、Myf6均能显著提高关岭牛MyoD1启动子全长P1的转录活性(P＜0.05);而外源过表达转录因子 MyoD基因家族不能显著提高关岭牛MyoD1启动子核心区P2的转录活性。说明关岭牛MyoD、Myf5和Myf6转录因子与关岭牛MyoD1启动子的作用位点不在其核心启动子区P2上。     

正确建立系统的数学模型 追索真正的优化点

本文采用理论与试验结合的方法,就怎样得出正确数学模型,追索真正优化点进行了五个方面的探讨。分析得出:单纯用t检验,不能完全反映各参数对指标的影响程度;回归方程的有效范围根据试验条件的不同,绕理论值上下波动;回归模型的理论检验合格,不一定代表模型与实际拟合得很好;可以采用试验追索法,找出真正优化点。