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Kuhan Chandru Eiichi Imai Takeo Kaneko Yumiko Obayashi Kensei Kobayashi 《Origins of life and evolution of the biosphere》2013,43(2):99-108
We tested the stability and reaction of several amino acids using hydrothermal system simulators: an autoclave and two kinds of flow reactors at 200–250 °C. This study generally showed that there is a variation in the individual amino acids survivability in the simulators. This is mainly attributed to the following factors; heat time, cold quenching exposure, metal ions and also silica. We observed that, in a rapid heating flow reactor, high aggregation and/or condensation of amino acids could occur even during a heat exposure of 2 min. We also monitored their stability in a reflow-type of simulator for 120 min at 20 min intervals. The non-hydrolyzed and hydrolyzed samples for this system showed a similar degradation only in the absence of metal ions. 相似文献
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Kuhan Perampaladas J. A. Stoltz & M. C. B. Andrade 《Ethology : formerly Zeitschrift fur Tierpsychologie》2008,114(6):589-598
In many species, selection acts on males to recognize female reproductive status at a distance using pheromones. Unmated females may actively seek to attract males; however, mated females may become cryptic to avoid attracting additional males if multiple matings are costly. Although females of many species cease pheromone production after mating, it is often unclear whether this is a strategic part of a female reproductive strategy, or whether this is because of chemical manipulation by males. If variation in pheromone production is part of the female’s strategy, then we predicted mated females should eventually re‐advertise receptivity if the benefits of multiple mating increase with time since copulation (e.g. because of sperm depletion). Here, we tested this prediction in Australian redback spiders (Latrodectus hasselti). First, we replicated earlier results by showing that virgin males discriminate female maturity and mating status based exclusively on web‐borne chemicals. Our results show this difference must arise from a change in chemical deposition in the web as we controlled for web volume differences between mated and virgin females. Male activity on extracts from webs of virgin females exceeded activity on a solvent control and on extracts of webs of just‐mated females—confirming that female redbacks cease pheromone production immediately after mating. Second, we tested a new prediction that mated females might re‐advertise receptivity near the end of their normal breeding season to replenish diminished sperm stores prior to overwintering. Consistent with the prediction of strategic advertisement, we show that male activity on extracts from females’ webs increased significantly 3 mo after the female first mated (typical length of the breeding season). Thus, these females had begun to add pheromone to their web again. At this time, 26% of these females re‐mated with a second male. If females re‐advertise receptivity to ensure adequate sperm stores, then we predicted a positive relationship between female reproductive output during the 3‐mo interval after copulation and the subsequent intensity of male response to web extracts. However, differences in male activity time were not related to the total number of spiderlings or the number of egg sacs a female had produced during the 3‐mo interval after the first copulation. This result could arise if male chemical manipulation of female receptivity decreases with time after copulation, or if the testing interval used in our study was too long to reveal variation in sperm depletion in females. Thus, although our results are consistent with the idea that females strategically alter pheromonal advertisement, we cannot distinguish this from the hypothesis that female receptivity arises from chemical manipulation by males. 相似文献
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Mariscal Carlos Barahona Ana Aubert-Kato Nathanael Aydinoglu Arsev Umur Bartlett Stuart Cárdenas María Luz Chandru Kuhan Cleland Carol Cocanougher Benjamin T. Comfort Nathaniel Cornish-Bowden Athel Deacon Terrence Froese Tom Giovannelli Donato Hernlund John Hut Piet Kimura Jun Maurel Marie-Christine Merino Nancy Moreno Alvaro Nakagawa Mayuko Peretó Juli Virgo Nathaniel Witkowski Olaf James Cleaves H. 《Origins of life and evolution of the biosphere》2019,49(3):111-145
Origins of Life and Evolution of Biospheres - In this review, we describe some of the central philosophical issues facing origins-of-life research and provide a targeted history of the developments... 相似文献
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