12 The Dauer Larva
12 The Dauer Larva
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12 道尔幼虫
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发表时间：
1988
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通讯作者：
D. Riddle
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作者：
D. Riddle
I.引言的dauer，或“持久的”，秀丽隐杆线虫幼虫阶段是兼性滞育的一个例子。环境因素作为一个接受的发展阶段（L1幼虫）的信号，导致改变生理和发育潜力，导致形成专门的传播和长期生存的第三阶段幼虫。Dauer幼虫能够主动运动，但它们不进食。它们具有独特的形态和抗应激能力，在能量代谢中发生改变，并在发育和衰老中被阻止。Dauer幼虫的存活时间是绕过Dauer阶段的动物的3周寿命的4到8倍。道尔状态本身被认为是不老化的，因为道尔阶段的持续时间不影响后道尔寿命（Klass和Hirsh 1976）。就目前所知，贮存能量的消耗可能是限制dauer幼虫寿命的主要因素。各种形式的滞育在线虫中很常见，在C. elegans dauer幼虫和被记录为许多寄生虫物种生命周期中的强制性阶段的发育停滞形式（参见Michel 1974; Evans和佩里1976）。在许多情况下，这些停滞阶段是专门在宿主感染之间的时期存活的传播形式（Riddle和Bird 1985）。Dauer幼虫表现出在其他阶段没有观察到的行为。咽部泵血完全被抑制，幼虫经常一动不动地躺着。尽管昏昏欲睡，但他们确实表现出消极的反应...
I. INTRODUCTION The dauer, or “enduring,” larval stage of Caenorhabditis elegans is an example of facultative diapause. Environmental factors act as signals to a receptive developmental stage (the L1 larva), resulting in altered physiology and developmental potential that leads to formation of a third-stage larva specialized for dispersal and long-term survival. Dauer larvae are capable of active movement, but they do not feed. They have a unique morphology and resistance to stress, are altered in energy metabolism, and are arrested in development, as well as aging. Dauer larvae survive four to eight times the 3-week life span of animals that have bypassed the dauer stage. The dauer state itself has been considered to be nonaging, because the duration of the dauer stage does not affect postdauer life span (Klass and Hirsh 1976). As far as is known, the consumption of stored energy may be the major factor limiting dauer larva life expectancy. Various forms of diapause are common among nematodes, and there may be interesting parallels between the C. elegans dauer larva and arrested developmental forms that have been documented as obligatory stages in the life cycles of a number of parasitic species (for review, see Michel 1974; Evans and Perry 1976). In many cases, these arrested stages are dispersal forms specialized to survive periods between host infections (Riddle and Bird 1985). Dauer larvae exhibit behavior not observed in other stages. Pharyngeal pumping is completely suppressed, and the larvae often lie motionless. Although lethargic, they do show a negative response...