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Targeting Proteins for Degradation by Arabidopsis COP1： Teamwork Is What Matters

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Journal of Integrative Plant Biology 2007年第1期49卷 35-42页

作者： Rongcheng Lin Haiyang Wang Boyce Thompson Institute for Plant Research Comell University Ithaca NY 14853 USA

Arsbidopsis COP1 （Constitutive Photomorphogenic 1） defines a key repressor of photomorphogenesis in darkness by acting as an E3 ubiquitin Iigase in the nucleus, and is responsible for the targeted degradation of a number of photomorphogenesis-promoting factors, including phyA, HY5, LAF1, and HFR1. Light activation of multiple classes of photoreceptors （including both phytochromes and cryptochromes） inactivates COP1 and reduces its nuclear abundance, allowing the accumulation of these positively acting light signaling intermediates to promote photomorphogenic development. Recent studies suggest that Arabidopsis COP1 teams up with a family of SPA proteins （SPA1-SPA4） to form the physiologically active COP1-SPA E3 ubiquitin ligase complexes. These COP1-SPA complexes play overlapping and distinct functions in regulating seedling photomorphogenesis under different light conditions and adult plant growth. Further, the COP1-SPA complexes act In concert at a biochemical level with the CDD （COP10, DET1, and DDB1） complex and COP9 signalosome （CSN） to orchestrate the repression of photomorphogenesis.

关键词： Arabidopsis COP1 E3 ligase photomorphogenesis proteolysis SPA

Involuntary Unemployment： An Expository Note

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2018年第1期13卷 83-92页

作者： Henry Y. Wan Jr. Department of Economics Comell University Ithaca NY 14853 USA

This note is an effort to view the research program of Brecher and his co-workers to deploy tax incentives against involuntary unemployment in the broader context; on both the equity-efficiency trade-off in political ... 详细信息

关键词： involuntary unemployment efficiency wage wage rigidity

Managing water for life

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Frontiers of Environmental Science & Engineering 2012年第2期6卷 255-264页

作者： Daniel P.LOUCKS Haifeng JIA Civil and Environmental Engineering Comell UniversityIthaca NY 14853USA School of Environment Tsinghua UniversityBeijing 100084China

Water is essential for life. In spite of the entire engineering infrastructure devoted to the treatment, regulation and beneficial uses of water, occasionally sufficient quantities and qualities of water become scarce. When this happens, just how do we decide how much less water to allocate to all of us and the activities we engage in to sustain and enhance our quality of life? This paper addresses some of the complexities of answering such a question, especially as society increasingly recognizes the need to provide flow regimes that will maintain healthy aquatic and floodplain ecosystems that also impact the economic, physical and even the spiritual quality of our lives. For we depend on these ecosystems to sustain our wellbeing. We are indeed a part of our ecosystems. We depend upon on aquatic ecosystems to moderate river flow qualities and quantities, reduce the extremes of floods and droughts, reduce erosion, detoxify and decompose waterborne wastes, generate and preserve flood plain soils and renew their fertility, regulate disease carrying organisms, and to enhance recreational benefits of river systems. This question of deciding just how much water to allocate to each water user and for the maintenance of viable aquatic ecosystems, especially when there is not enough, is a complex, and largely political, issue. This issue is likely to become even more complex and political and contentious in the future as populations grow and as water quantities and their qualities become even more variable and uncertain.

关键词： water stress aquatic ecosystems sustainablewater resource allocations ecosystem water requirements

Founder effects and the evolution of asymmetrical sexual isolation in a rapidly-speciating clade

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Current Zoology 2013年第2期59卷 230-238页

作者： Kevin R OH Gina L. CONTE Kerry L. SHAW Department of Neurobiology and Behavior Comell University Ithaca NY 14853 USA Department of Biology University of Maryland College Park MD 20742 USA

Sexual isolation resulting from differences in mate choice behaviors is a hallmark of rapidly-speciating lineages. When present, asymmetrical sexual isolation may provide insights into the mechanisms responsible for the evolutionary change in mate signaling traits. In particular, Kaneshiro’s hypothesis suggests that divergence in sexual characters between populations may arise in allopatry when ‘derived’ founding populations are subject to severe population bottlenecks, accompanied by a relaxation of sexual selection relative to ‘ancestral’ source populations. In the present study, we tested predictions of asymmetrical sexual isolation between two allopatric species of HawaiianLaupalacrickets, representing ‘ancestral’ (L. makaio) and ‘derived’ (L. nigra) taxa. While crickets in this genus are notable for rapid divergence of male courtship songs, these species share similar song types, thus suggesting that patterns of sexual isolation are likely due to other mating cues. Analysis of behavioral responses in conspecific and heterospecific ‘no-choice’ mating trials revealed pronounced asymmetrical isolation in the direction predicted by Kaneshiro’s hypothesis, wherein we observed a significant reduction in mating success for crosses involving ‘derived’ males paired with ‘ancestral’ females, compared to the reciprocal heterospecific and both conspecific pairings. Further dissection of courtship behaviors suggested this difference did not reflect male mate choice, but rather, marked reduced spermatophore acceptance rates by ‘ancestral’ females paired with ‘derived’ males. The results are discussed with respect to founder effect models of speciation and the potential role of chemosensory signals in mate choice in these species.

关键词：不对称性演变方正择偶行为信号特征交配试验生殖隔离行为反应

Compulsive Repetition of Rupture： Strategies of Representing Trauma

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Frontiers of Literary Studies in China-Selected Publications from Chinese Universities 2015年第2期9卷 147-159页

作者： Edward M. G_unn Department of Asian Studies Comell University Ithaca NY 14853 USA

This article focuses on the strategies that literature and cultural criticism adopt to represent trauma in comparison to a current medical definition. The contemporary medical definition, trauma as post-traumatic stress disorder （PTSD）, is the most narrow and specific definition to discuss trauma. The discourse of medicine does not necessarily match those of literature and cultural criticism, nor need they conform to each other. PTSD includes a collection of symptoms, any one of which might not have anything to do with traumatic experience, but which together point with increasing intensity to a psychological syndrome caused by traumatic shock. Although this is historically a recently defined syndrome （1980）, its features had long before attracted attention and been recorded under other terms and diagnoses. Although Chinese literature is only occasionally given to psychological realism, we do find occasional descriptions that strongly suggest aspects of the syndrome. Also, the aims and the needs of medicine and literature or cultural criticism are not necessarily the same, but it is important to explore in greater detail the aims and the needs of literature and cultural criticism.

关键词： strategies of representing trauma traumatic memories compulsiverepetition modem and contemporary Chinese literature

Resazurin reduction and other tests of semen quality and fertility of bulls

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Asian Journal of Andrology 1999年第3期1卷 109-114页

作者： Robert H.Foote Department of Animal Science Comell University Ithaca NY 14853-4801 USA

Aim: This study was undertaken to compare the reduction in color of two dyes methylene blue (MBRT) and resazurindye (RRT) with other tests of bull semen quality and to examine their relationship to fertility. Methods: One hundredsixty-four ejaculates from 59 bulls were examined, processed, and used for 30 016 inseminations. Results: Bulls usedin artificial insemination have been selected for high semen quality and fertility, and semen from these bulls averaged80.6 % unstained sperm, only 11% had abnormalities, and fertility ranged from 64 %to 76 %. The MBRT and RRTwere run with standardized sperm numbers to prevent sperm concentration from influencing the dye reduction time. Ashort RRT was correlated with higher fertility ( r = -0.26) but MBRT was not correlated ( r = -0.05, P >0.0,5).The correlations were low, but axe typical and reflect the statistical effect of the large binomial variance associated withpregnancy or nonpregnancy being coded as 1 or O. Conclusion: The fact that the RRT was significantly correlated withfertility when sperm numbers were standardized, and published reports that resazurin is useful for monitoring other semencharacteristics, indicate that this dye may provide valuable information not given by other simple laboratory tests. (AsianJ Androl 1999 Sep; 1: 109 - 114 )

关键词： fertility semen spermatozoa cattle resazurin reduction

An integrative view of the signaling phenotype： Dynamic links between signals, physiology, behavior and social context

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Current Zoology 2014年第6期60卷 739-754页

作者： Maren N. VITOUSEK David M. ZONANA Rebecca J. SAFRAN Department of Neurobiology and Behavior Comell University Ithaca New York 14853 USA Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309 USA

Signal traits are often linked with the physiological state and behavior of their bearer. Direct examination of the causal links among these variables has provided substantial insight into the information content of signals, and into the costs and benefits of signal expression. Yet recent empirical work suggests that the social context in which signals are developed and displayed can play a major role not only in how signals are received, but also in coordinating and mediating the signaling phenotype itself. Here we review both well-established and emerging evidence for direct feedbacks among an individual’s physiological state, behavior, and signal elaboration. We then describe an integrative view of signaling that takes into account the bidirectional relationships among components of phenotype and the social context in which signals are developed and displayed. Integrating dynamic feedback between context and phenotype within models of the evolution and maintenance of signals may yield insights into how signals evolve, how signaling phenotypes are coordinated and maintained on ecological and evolutionary time scales, and how static signals continue to convey relevant phenotypic information about their bearer through time.

关键词：信号特征生理状态社会环境表型信令动态链接行为信息内容

Endocrine correlates of mate choice and promiscuity in females of a socially monogamous avian mating system with alternative male reproductive phenotypes

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Current Zoology 2014年第6期60卷 804-815页

作者： Hubert SCHWABL Willow R. LINDSAY Douglas G. BARRON Michael S. WEBSTER School of Biological Sciences and Center for Reproductive Biology Washington State University Pullman WA 99164-4236 USA Department of Department of Biological and Environmental Sciences Goteborg University Box 463405 30 Goteborg Sweden Department of Psychology University of South Florida Tampa FL 33620-7200 USA Department of Neurobiology and Behavior and Comell Laboratory for Ornithology Comell University Ithaca NY 14850 USA

While our understanding of male reproductive strategies is informed by extensive investigations into endocrine mechanisms, the proximate mechanisms by which females compete for mates and adjust reproduction to social environment remains enigmatic. We set out to uncover endocrine correlates of mate choice, social environment, and reproductive investment in female red-backed fairy-wrensMalurus melanocephalus. In this socially monogamous, yet highly sexually promiscuous species, females experience discrete variation in the phenotype of their mates, which vary in both plumage signals and level of paternal care, and in the composition of their breeding groups, which consist of either the pair alone or with an additional cooperative auxiliary; female investment varies according to these social parameters. We found that androgen, estrogen, and glucorticoid levels varied with reproductive stage, with highest androgen and estrogen concentrations during nest construction and highest corticosterone concentrations during the pre-breeding stage. These stage-dependent patterns did not vary with male phenotype or auxiliary presence, though androgen levels during pre-breeding mate selection were lower in females obtaining red/black mates than those obtaining brown mates. We found no evidence that androgen, estrogen, or corticosterone levels during the fertile period were related to extra-pair young (EPY) frequency. This study demonstrates clear changes in steroid levels with reproductive stage, though it found little support for variation with social environment. We suggest hormonal responsiveness to social factors may be physiologically constrained in ways that are bypassed through exogenous hormone manipulations.

关键词：内分泌机制社会环境男性生殖一夫一妻制表型变异女性交配系统择偶

Ecological and evolutionary connections between morphology, physiology, and behavior

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Current Zoology 2014年第6期60卷 736-738页

作者： Rebecca J. SAFRAN Maren N. VITOUSEK Guest Editors Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309 USA Department of Neurobiology and Behavior Comell University Ithaca New York 14853 USA

Phenotype variation within populations both provides the raw material for and is the product of evolutionary change. An individual's phenotype, defined as the amalgamation of morphology, physiology, and behavior, is highly complex. It has been common to try to isolate each of these aspects of phenotype rather than directly examine their integration. For example, despite the demonstrated importance of single aspects of phenotype for acquiring mates it is well known that signal traits are not evaluated in isolation, but rather in conjunction with associated behaviors, and sometimes with other signal traits (Moller and Pomiankowski, 1993; Candolin, 2003; Hebets and Papaj, 2005; Hebets, 2011). Indeed, the multidimensional components of phenotype are influenced by a dynamic interplay among morphology, physiology, and behavior, as well as the social and environmental context in which phenotypes are expressed. Such interactive feedbacks indicate that current models of the function and evolution of complex phenotypes, including those used as signal traits, must be updated to incorporate these dynamic interactions.

关键词：形态学生理学行为进化表型变异连接生态信号特性