Induction of larval attachment and metamorphosis in the serpulid polychaete Hydroides elegans by dissolved free amino acids:isolation and identification

Harder, Tilmann; Qian, Pei‐Yuan

doi:10.3354/meps179259

Cited by 36 publications

(18 citation statements)

References 16 publications

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“…Larvae were cultured according to the methods described in Harder & Qian (1999). Competent larvae were sieved from culture batches (110 pm mesh) and quickly resuspended into 2 sterilized glass beakers filled with 0.22 pm filtered seawater (FSW) and FSW containing antibiotics (2.5 X 10-4 M streptomycin and 1.0 X 10-4 M penicillin), respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Bioassays were performed following the methodology described in Bryan et al (1998) andHarder &Qian (1999). In addition, samples were generally filter-sterilized (0.22 pm) prior to bioassays.…”

Section: Methodsmentioning

confidence: 99%

“…Qualitative and quantitative DFAA analysis by pre-column derivatization with ortho-phthaldialdehyde (Lindroth & Mopper 1979) was performed according to the methods described in Harder & Qian (1999). All solvents and chemicals used in this study were r.g.-grade; purified water was obtained from a Milli-Q Reagent-Water-System (Millipore).…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we reported the bioassay-guided chromatographic isolation of the presumptive larval settlement cue for Hydrojdes eleyans from the extract of conspecific adults and the leachate of Bugula nentina (Harder & Qian 1999). In both samples, we identified a biologically active mixture of 10 polar, aliphatic, dissolved free amino acids (DFAA).…”

Section: Introductionmentioning

confidence: 99%

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Induction of larval attachment and metamorphosis in the serpulid polychaete Hydroides elegans by dissolved free amino acids:mode of action in laboratory bioassays

Beckmann¹,

Harder²,

Qian³

1999

Mar. Ecol. Prog. Ser.

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Larval Settlement in the serpulid polychaete Hydroides elegans (Haswell) reportedly occurs in response to both an attractive bactenal film and polar, aliphatic dissolved free amino acids (DFAA). In this study, we tested whether the larval metamorphic response was caused by direct DFAA perception or by induction of DFAA-utilizing bactena in assay dishes. Süii-water laboratory assays were performed with sterile measures in the presence and absence of an antibiotic rnixture (2.5 X 10-4 M streptomycin, 1.0 X 10-4 M peniciilin). In the absence of these antibiotics our results revealed a significant correlation between DFAA decrease rates, bactenal film development and larval metamorphosis within a 24 h assay period. After 12 h, DFAA concentrations decreased below the detection limit of 0.013 PM. the attached bactenal density in assay dishes was approx. 2 X 104 cells mm-', and larval metamorphosis was insignificantly low (20%). After 24 h, DFAA were no longer detectable, the attached bactenal density was unchanged. and larval metamorphosis was significantly high (50%). In contrast, naturally biofdmed dishes showed a significant metamorphic response of 50% after I 2 h. In analogous experiments in the presence of antibiotics, the percentage of larval metamorphosis vaned between 3 and 34% after 24 h whde the number of attached bactena was low (0.5 to 5 X lo3 ceiis mrn-' 1. We assume that the metamorphic response in these treatrnents was caused by inductive, antibiotic-resistant bactena. Our results suggest that larval metamorphosis was exclusively tnggered by an inductive bactenal film rather than by direct larval perception of DFAA. Despite most sterile measures at the set-up of bioassays, bactena were inevitably inoculated into test dishes as they were found associated with the larva and suspended in the larval culture water. Therefore, our results point to a systematic error in this established assay procedure. If putative signaling compounds serve as a nutrition source for larval settlement inducing manne bactena, we conclude that an explicit investigation of a chemical metamorphic cue's efficacy is unreliable. The ecological significance of the transformation of DFAA into an attractive bactenal film for larval attachment and metamorphosis in H. elegans is discussed.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Induction of larval attachment and metamorphosis in the serpulid polychaete Hydroides elegans by dissolved free amino acids:mode of action in laboratory bioassays

Beckmann¹,

Harder²,

Qian³

1999

Mar. Ecol. Prog. Ser.

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“…Adult broodstocks of the polychaete Hydroides elegans (Haswell) and the bryozoan Bugula neritina (Linnaeus) were collected from piling and floating rafts in Port Shelter Bay, Hong Kong (22°19' N, 114°16' W). Batch cultures of polychaete larvae were reared for 5 d to competent stage according to Harder & Qian (1999). Bryozoan larvae were obtained according to Bryan et al (1997), and newly hatched larvae were included in bioassays.…”

Section: Methodsmentioning

confidence: 99%