Publications (6)14.77 Total impact
-
Article: Assessing the effects of polychlorinated biphenyls (Aroclor 1254) on a scleractinian coral (Stylophora pistillata) at organism, physiological, and molecular levels.
[show abstract] [hide abstract]
ABSTRACT: Polychlorinated biphenyls (PCBs) are a group of widespread contaminants, and accumulation of PCBs has been observed in corals in the field. However, the toxic effects of PCBs on corals have not been investigated. In this study, we tested short and long term toxicity of Aroclor 1254, a commercial PCB mixture, on the scleractinian coral Stylophora pistillata. Coral nubbins were incubated in either control seawater or seawater dosed with PCBs (approximately 300ng/L) for 96h. The effect of PCB exposure on coral gene expression at 4h post exposure was tested with the suppression subtractive hybridization (SSH) and quantitative PCR methods. Photosystem II activity of the zooxanthellae was measured at 96h. After the exposure, nubbins were moved into clean seawater and their survival and growth were observed for another 50 days. All nubbins survived during the exposure and the following 50-d recovery period. Photosystem II activity and coral growth were not affected by PCB exposure in this study. Fifty-four clones were sequenced for gene expression analysis, and 15% of these sequences were identified, including genes involved in general stress response, peptide metabolism, cellular receptor, cytoskeleton organization, membrane trafficking, and oxidative stress response. However, the quantitative PCR did not show significant difference in the five selected genes. In conclusion, acute exposure of S. pistillata to Aroclor 1254 at 300ng/L did not affect coral survival, photosynthesis or growth but may alter the expression of certain genes involved in various important cellular functions. The nubbin technique proved to be an efficient approach to simultaneously characterize the impact of PCBs on the corals at multiple biological levels.Ecotoxicology and Environmental Safety 09/2011; 75(1):207-12. · 2.29 Impact Factor -
Article: ApRab11, a cnidarian homologue of the recycling regulatory protein Rab11, is involved in the establishment and maintenance of the Aiptasia-Symbiodinium endosymbiosis.
[show abstract] [hide abstract]
ABSTRACT: Endosymbiotic association of the Symbiodinium dinoflagellates (zooxanthellae) with their cnidarian host cells involves an alteration in the development of the alga-enclosing phagosomes. To uncover its molecular basis, we previously investigated and established that the intracellular persistence of the zooxanthella-containing phagosomes involves specific alga-mediated interference with the expression of ApRab5 and ApRab7, two key endocytic regulatory Rab proteins, which results in the selective retention of the former on and exclusion of the later from the organelles. Here we examined the role of ApRab11, a cnidarian homologue of the key endocytic recycling regulator, Rab11, in the Aiptasia-Symbiodinium endosymbiosis. ApRab11 protein shared 88% overall sequence identity with human Rab11A and contained all Rab-specific signature motifs. Co-localization and mutagenesis studies showed that EGFP-tagged ApRab11 was predominantly associated with recycling endosomes and functioned in the recycling of internalized transferrin. In phagocytosis of latex beads, ApRab11 was quickly recruited to and later gradually removed from the developing phagosomes. Significantly, although ApRab11 immunoreactivity was rapidly detected on the phagosomes containing either newly internalized, heat-killed zooxanthellae, or resident zooxanthellae briefly treated with the photosynthesis inhibitor DCMU, it was rarely observed in the majority of phagosomes containing either newly internalized live, or healthy resident, zooxanthellae. It was concluded that through active exclusion of ApRab11 from the phagosomes in which they reside, zooxanthellae interfere with the normal recycling process required for efficient phagosome maturation, and thereby, secure their intracellular persistence, and consequently their endosymbiotic relationship with their cnidarian hosts.Biochemical and Biophysical Research Communications 01/2006; 338(3):1607-16. · 2.48 Impact Factor -
Article: Molecular cloning of Rab5 (ApRab5) in Aiptasia pulchella and its retention in phagosomes harboring live zooxanthellae.
[show abstract] [hide abstract]
ABSTRACT: The intracellular association of symbiotic dinoflagellates (zooxanthellae) with marine cnidarians is the very foundation of the highly productive and diversified coral reef ecosystems. To reveal its underlying molecular mechanisms, we previously cloned ApRab7, a Rab7 homologue of the sea anemone Aiptasia pulchella, and demonstrated its selective exclusion from phagosomes containing live zooxanthellae, but not from those containing either dead or photosynthesis-impaired algae. In this study, Rab5 was characterized, due to its key role in endocytosis and phagocytosis acting upstream of Rab7. The Aiptasia Rab5 homologue (ApRab5) is 79.5% identical to human Rab5C and contains all Rab-specific signature motifs. Subcellular fractionation study showed that ApRab5 is mainly cytosolic. EGFP reporter and phagocytosis studies indicated that membrane-associated ApRab5 is present in early endocytic and phagocytic compartments, and is able to promote their fusion. Significantly, immunofluorescence study showed that the majority of phagosomes containing either resident or newly internalized live zooxanthellae were labeled with ApRab5, while those containing either heat-killed or photosynthesis-impaired algae were mostly negative for ApRab5 staining whereas the opposite was observed for ApRab7. We propose that active phagosomal retention of ApRab5 is part of the mechanisms employed by live zooxanthellae to: (1) persist inside their host cells and (2) exclude ApRab7 from their phagosomes, thereby, establishing and/or maintaining an endosymbiotic relationship with their cnidarian hosts.Biochemical and Biophysical Research Communications 12/2004; 324(3):1024-33. · 2.48 Impact Factor -
Article: Briarane derivatives from the gorgonian coral Junceella fragilis.
[show abstract] [hide abstract]
ABSTRACT: A new trihydroxyl briarane-type diterpenoid, junceellolide H (1), along with two known compounds, praelolide (2) and junceellin (3), have been isolated from the gorgonian coral Junceella fragilis. The structure, including the relative configuration of the new diterpenoid 1, was elucidated by extensive spectroscopic methods.CHEMICAL & PHARMACEUTICAL BULLETIN 01/2004; 51(12):1429-31. · 1.59 Impact Factor -
Article: Molecular identification of Rab7 (ApRab7) in Aiptasia pulchella and its exclusion from phagosomes harboring zooxanthellae.
[show abstract] [hide abstract]
ABSTRACT: The establishment and maintenance of the intracellular association between marine cnidarians and their symbiotic microalgae is essential to the well being of coral reef ecosystems; however, little is known concerning its underlying molecular mechanisms. In light of the critical roles of the small GTPase, Rab7, as a key regulator of vesicular trafficking, we cloned and characterized the Rab7 protein in the endosymbiosis system between the sea anemone, Aiptasia pulchella and its algal symbiont, Symbiodinium spp. The Aiptasia homologue of Rab7 proteins, ApRab7 is 88% identical to human Rab7 protein and contains all Rab-specific signature motifs. Results of EGFP reporter analysis, protein fractionation, and immunocytochemistry support that ApRab7 is located in late endocytic and phagocytic compartments and is able to promote their fusion. Significantly, the majority of phagosomes containing live symbionts that either have taken long residency in, or were newly internalized by Aiptasia digestive cells did not contain detectable levels of ApRab7, while most phagosomes containing either heat-killed or photosynthesis-impaired symbionts were positive for ApRab7 staining. Overall, our data suggest that live algal symbionts persist inside their host cells by actively excluding ApRab7 from their phagosomes, and thereby, establish and/or maintain an endosymbiotic relationship with their cnidarian hosts.Biochemical and Biophysical Research Communications 09/2003; 308(3):586-95. · 2.48 Impact Factor -
Article: Cloning and characterization of the first cnidarian ADP-ribosylation factor, and its involvement in the Aiptasia-Symbiodinum endosymbiosis.
[show abstract] [hide abstract]
ABSTRACT: Marine cnidarian-microalgal endosymbiosis is a form of intracellular association that contributes greatly to the high primary productivity of reefs; however, little is known about its molecular mechanisms. Since the ADP-ribosylation factor (ARF) family proteins are key regulators of host intracellular vesicle transport systems, which are critical to many endosymbiotic interactions, we set out to clone and characterize ARF proteins in the symbiotic sea anemone Aiptasia pulchella. Experiments indicated that at least 3 ARF protein classes (class I, class II and class III) were present and expressed as a single messenger RNA species in Aiptasia, with highest mRNA expression levels for apARF1, medium for apARF5, and lowest for apARF6. Quantitative analysis revealed a great reduction at both the RNA and the protein levels in apARF1, but not apARF5 and apARF6, in the symbiotic animals. The apARF1 protein was highly homologous in sequence to other known ARF1 proteins and displayed a Golgi-like localization pattern. Overall, our study identified apARF1 as a potential negative regulator of Aiptaisia-microalgal endosymbiosis.Marine Biotechnology 6(2):138-47. · 3.43 Impact Factor
Top co-authors
Top Journals
Institutions
-
2004–2006
-
National Kaohsiung Marine University
Kaohsiung, Kaohsiung, Taiwan
-
-
2003
-
National Museum of Marine Biology and Aquarium, Taiwan
Pingtung, Taiwan, Taiwan
-
