Biofilm cue for larval settlement in Hydroides elegans (Polychaeta): is contact necessary?
Biofilm cue for larval settlement in Hydroides elegans (Polychaeta): is contact necessary?
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DOI：
10.1007/s00227-014-2529-0
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发表时间：
2014-11-01
期刊：
影响因子：
2.4
通讯作者：
Koehl, M. A. R.
中科院分区：
文献类型：
--
作者：
Hadfield, Michael G.;Nedved, Brian T.;Koehl, M. A. R.
许多固着海洋无脊椎动物的幼虫在表面微生物群落(生物膜)的响应下定居，但生物膜中的可溶性化合物对幼虫在定居、附着和变态前的行为的影响研究很少。这个问题是通过摄录锯齿目线虫的合格幼虫在诱导定居的生物膜上的行为来解决的。成虫于2012年11月在美国夏威夷珍珠港被采集，并几乎立即产卵。将6日龄幼虫放入5个重复处理的小杯中：(1)自然生物膜；(2)在8亩米的筛子上，在干净的杯底上方1 mm处；(3)在干净的筛子下；(4)在干净的杯子里；(5)在干净的杯子里。使用录像带，在将幼虫放入处理后的5分钟内，对幼虫的游泳速度和轨迹进行了量化。只有接触生物膜的幼虫，即在处理(1)和(2)中，会放慢它们的游泳速度，增加爬行而不是游泳的时间。这表明在这些条件下，生物膜发出的任何可溶线索都不会影响沉降行为。此外，24小时后，两个可接触的生物膜处理组的幼虫几乎100%已经变态，而在包括清洁屏幕下的生物膜和完全没有生物膜的处理组，15%的幼虫已经变态，这强烈表明在较长的时间内，生物膜不会产生可溶的定居迹象。
Larvae of many sessile marine invertebrates settle in response to surface microbial communities (biofilms), but the effects of soluble compounds from biofilms in affecting larval behavior prior to settlement, attachment, and metamorphosis have been little studied. This question was addressed by videotaping the behavior of competent larvae of the serpulid, Hydroides elegans, above settlement-inducing biofilms. Adult worms were collected in Pearl Harbor, Hawaii, USA in November 2012 and spawned almost immediately. Six-day old larvae were placed in five replicated treatments in small cups: (1) with a natural biofilm; (2) with a natural biofilm on an 8-A mu m screen, 1 mm above the bottom of a clean cup; (3) with a natural biofilm beneath a clean screen; (4) in a clean cup; and (5) in a clean cup with a clean screen. Using the videotapes, larval swimming speeds and trajectories were quantified within 5 min of the larvae being placed in a treatment. Only larvae that touched a biofilm, i.e., in treatments (1) and (2), slowed their swimming speed and increased the amount of time spent crawling rather than swimming. This shows that under these conditions, any soluble cues emanating from a biofilm do not affect settlement behavior. Furthermore, after 24 h close to 100 % of larva in the two accessible biofilm treatments had metamorphosed and < 15 % in treatments that included a biofilm under a clean screen and no biofilm at all, strongly suggesting that soluble cues for settlement were not produced by the biofilms over the longer time period.