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Chen J.,Jinan University | Chen J.,Quarantine Bureau Technology Center | Ye Q.,Jinan University | Gu H.-F.,Third Institute of Oceanography | And 4 more authors.
Harmful Algae

Members of the Alexandrium tamarense species complex are some of the most important toxigenic dinoflagellates and are also widely distributed along the coast of China. A. tamarense and another well-known toxic raphidophycean alga, Chattonella marina, are usually found in the same sea areas, sometimes at the same place and time. In this study, under laboratory co-culture conditions, we found that most of the 15 A. tamarense strains from the South China Sea and the East China Sea had significant inhibition on the growth of C. marina, while most of the A. tamarense strains were inhibited to various extents by C. marina. These results suggest that there is a complex reciprocal inhibitory effect between A. tamarense and C. marina, which might be caused by their allelopathic potency, the intrinsic growth rate of the algal species and the sensitivity of the target alga to the allelochemicals, etc. However, no strict correlations were observed between the allelopathic actions and the geographical distribution. The allelopathic potency observed in co-culture did not correlate with the hemolytic activity of the extracellular toxins obtained by the solvent extraction method (p>. 0.05) but did correlate with the hemolytic activity obtained by the dialysis method (p<. 0.01). These results indicate that various strains of A. tamarense could produce diverse hemolytic substances with different compositions and properties, which might be responsible for the variability in A. tamarense allelopathic action. © 2015 Elsevier B.V. Source

Yue Q.,Quarantine Bureau Technology Center | Wu K.,Quarantine Bureau Technology Center | Qiu D.,Quarantine Bureau Technology Center | Hu J.,Quarantine Bureau Technology Center | And 4 more authors.

Background: Hebardina concinna is a domestic pest and potential vector of pathogens throughout East and Southeast Asia, yet identification of this species has been difficult due to a lack of diagnostic morphological characters, and to uncertainty in the relationship between macroptyrous (long-winged) and brachypterous (small-winged) morphotypes. In insects male genital structures are typically species-specific and are frequently used to identify species. However, male genital structures in H. concinna had not previously been described, in part due to difficulty in identifying conspecifics.Methods/Principal Findings: We collected 15 putative H. concinna individuals, from Chinese populations, of both wing morphotypes and both sexes and then generated mitochondrial COI (the standard barcode region) and COII sequences from five of these individuals. These confirmed that both morphotypes of both sexes are the same species. We then dissected male genitalia and compared genital structures from macropterous and brachypterous individuals, which we showed to be identical, and present here for the first time a detailed description of H. concinna male genital structures. We also present a complete re-description of the morphological characters of this species, including both wing morphs.Conclusions/Significance: This work describes a practical application of DNA barcoding to confirm that putatively polymorphic insects are conspecific and then to identify species-specific characters that can be used in the field to identify individuals and to obviate the delay and cost of returning samples to a laboratory for DNA sequencing. Copyright: © 2014 Yue et al. Source

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