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51.
Environmental stress response in plants has been studied using a wide range of approaches, from lab-based investigation of biochemistry and genetics, to glasshouse studies of physiology and growth rates, to field-based trials and ecological surveys. It is also possible to investigate the evolution of environmental stress responses using macroevolutionary and macroecological analyses, analysing data from many different species, providing a new perspective on the way that environmental stress shapes the evolution and distribution of biodiversity. “Macroevoeco” approaches can produce intriguing results and new ways of looking at old problems. In this review, we focus on studies using phylogenetic analysis to illuminate macroevolutionary patterns in the evolution of environmental stress tolerance in plants. We follow a particular thread from our own research—evolution of salt tolerance—as a case study that illustrates a macroevolutionary way of thinking that opens up a range of broader questions on the evolution of environmental stress tolerances. We consider some potential future applications of macroevolutionary and macroecological analyses to understanding how diverse groups of plants evolve in response to environmental stress, which may allow better prediction of current stress tolerance and a way of predicting the capacity of species to adapt to changing environmental stresses over time. 相似文献
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LARS RAMSKÖLD 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1988,21(4):307-318
New material of early growth stages of the Silurian (Llandovery) trilobite Acernaspis is described. Pre-adult ontogenetic stages of this genus closely resemble adults of the post-Llandovery genus ***Ananaspis. A heterochronic descent of Ananaspis from Acernaspis is proposed. ***Ananaspis is interpreted as pae-domorphic, having arisen largely through neoteny. Neotenic changes already appear in the lineage in the last Acernaspis species, and Ananaspis then underwent continuous ncotcnic change throughout its known Silurian history. ▭ Heterochrony, neoteny, Silurian, Trilobita, Phacopidae, Acernaspis. Ananaspis. 相似文献
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Lindell Bromham 《Annals of botany》2015,115(3):333-341
Background Halophytes are rare, with only 0·25 % of angiosperm species able to complete their life cycle in saline conditions. This could be interpreted as evidence that salt tolerance is difficult to evolve. However, consideration of the phylogenetic distribution of halophytes paints a different picture: salt tolerance has evolved independently in many different lineages, and halophytes are widely distributed across angiosperm families. In this Viewpoint, I will consider what phylogenetic analysis of halophytes can tell us about the macroevolution of salt tolerance.Hypothesis Phylogenetic analyses of salt tolerance have shown contrasting patterns in different families. In some families, such as chenopods, salt tolerance evolved early in the lineage and has been retained in many lineages. But in other families, including grasses, there have been a surprisingly large number of independent origins of salt tolerance, most of which are relatively recent and result in only one or a few salt-tolerant species. This pattern of many recent origins implies either a high transition rate (salt tolerance is gained and lost often) or a high extinction rate (salt-tolerant lineages do not tend to persist over macroevolutionary timescales). While salt tolerance can evolve in a wide range of genetic backgrounds, some lineages are more likely to produce halophytes than others. This may be due to enabling traits that act as stepping stones to developing salt tolerance. The ability to tolerate environmental salt may increase tolerance of other stresses or vice versa.Conclusions Phylogenetic analyses suggest that enabling traits and cross-tolerances may make some lineages more likely to adapt to increasing salinization, a finding that may prove useful in assessing the probable impact of rapid environmental change on vegetation communities, and in selecting taxa to develop for use in landscape rehabilitation and agriculture. 相似文献
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Nandini Rao Deepali Jhamb Derek J Milner Bingbing Li Fengyu Song Mu Wang S Randal Voss Mathew Palakal Michael W King Behnaz Saranjami Holly LD Nye Jo Ann Cameron David L Stocum 《BMC biology》2009,7(1):1-25
Background
For membrane proteins, lipids provide a structural framework and means to modulate function. Paired connexin hemichannels form the intercellular channels that compose gap junction plaques while unpaired hemichannels have regulated functions in non-junctional plasma membrane. The importance of interactions between connexin channels and phospholipids is poorly understood.Results
Endogenous phospholipids most tightly associated with purified connexin26 or connexin32 hemichannels or with junctional plaques in cell membranes, those likely to have structural and/or modulatory effects, were identified by tandem electrospray ionization-mass spectrometry using class-specific interpretative methods. Phospholipids were characterized by headgroup class, charge, glycerol-alkyl chain linkage and by acyl chain length and saturation. The results indicate that specific endogenous phospholipids are uniquely associated with either connexin26 or connexin32 channels, and some phospholipids are associated with both. Functional effects of the major phospholipid classes on connexin channel activity were assessed by molecular permeability of hemichannels reconstituted into liposomes. Changes to phospholipid composition(s) of the liposome membrane altered the activity of connexin channels in a manner reflecting changes to the surface charge/potential of the membrane and, secondarily, to cholesterol content. Together, the data show that connexin26 and connexin32 channels have a preference for tight association with unique anionic phospholipids, and that these, independent of headgroup, have a positive effect on the activity of both connexin26 and connexin32 channels. Additionally, the data suggest that the likely in vivo phospholipid modulators of connexin channel structure-function that are connexin isoform-specific are found in the cytoplasmic leaflet. A modulatory role for phospholipids that promote negative curvature is also inferred.Conclusion
This study is the first to identify (endogenous) phospholipids that tightly associate with connexin channels. The finding that specific phospholipids are associated with different connexin isoforms suggests connexin-specific regulatory and/or structural interactions with lipid membranes. The results are interpreted in light of connexin channel function and cell biology, as informed by current knowledge of lipid-protein interactions and membrane biophysics. The intimate involvement of distinct phospholipids with different connexins contributes to channel structure and/or function, as well as plaque integrity, and to modulation of connexin channels by lipophilic agents. 相似文献57.
David M Sintasath Nathan D Wolfe Hao Qiang Zheng Matthew LeBreton Martine Peeters Ubald Tamoufe Cyrille F Djoko Joseph LD Diffo Eitel Mpoudi-Ngole Walid Heneine William M Switzer 《Retrovirology》2009,6(1):1-17
Background
RNA interference is a gene regulatory mechanism that employs small RNA molecules such as microRNA. Previous work has shown that HIV-1 produces TAR viral microRNA. Here we describe the effects of the HIV-1 TAR derived microRNA on cellular gene expression.Results
Using a variation of standard techniques we have cloned and sequenced both the 5' and 3' arms of the TAR miRNA. We show that expression of the TAR microRNA protects infected cells from apoptosis and acts by down-regulating cellular genes involved in apoptosis. Specifically, the microRNA down-regulates ERCC1 and IER3, protecting the cell from apoptosis. Comparison to our cloned sequence reveals possible target sites for the TAR miRNA as well.Conclusion
The TAR microRNA is expressed in all stages of the viral life cycle, can be detected in latently infected cells, and represents a mechanism wherein the virus extends the life of the infected cell for the purpose of increasing viral replication. 相似文献58.
Lindell Bromham 《Biology letters》2009,5(4):503-505
Analysis of DNA sequences now plays a key role in evolutionary biology research. If Darwin were to come back today, I think he would be absolutely delighted with molecular evolutionary genetics, for three reasons. First, it solved one of the greatest problems for his theory of evolution by natural selection. Second, it gives us a tool that can be used to investigate many of the questions he found the most fascinating. And third, DNA data confirm Darwin''s grand view of evolution. 相似文献
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中国野生印支虎及其猎物种群状况的野外实地研究一直处于空白。本研究使用足迹鉴别法、粪堆计数法,首次对西双版纳尚勇自然保护区野生印支虎种群数量现状及该区域内的虎猎物种群状况进行了调查研究。结果显示:2004 ~ 2009 年间,确认西双版纳保护区存在3 只成年印支虎个体(2 雌1 雄),西双版纳尚勇保护区拥有比较丰富的有蹄类种群,其中虎的主要猎物:水鹿平均密度为7.63 (7.40 ~ 9.23)只/ km2 ;赤麂平均密度为17. 39 (11.33 ~24.94)只/ km2 ,野猪平均密度为10.26 (7.69 ~ 14.51) 只/ km2 ,该区域虎猎物生物量为1 715. 74 kg/ km2 。本研究还探讨了该区域印支虎种群的保护前景以及中国境内开展虎种群调查的适用办法等。 相似文献
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Luís H Franco Pryscilla F Wowk Célio L Silva Ana PF Trombone Arlete AM Coelho-Castelo Constance Oliver Maria C Jamur Edson L Moretto Vânia LD Bonato 《Genetic vaccines and therapy》2008,6(1):1-11