Jiun-Hong Chen

Lysophospholipids increase IL‐8 and MCP‐1 expressions in human umbilical cord vein endothelial cells through an IL‐1‐dependent mechanism

Lysophosphatidic acid (LPA) and sphingosine 1‐phosphate (S1P) are both low‐molecular‐weight lysophospholipid (LPL) ligands which are recognized by the Edg family of G protein‐coupled receptors (GPCRs). In endothelial cells, these two ligands activate Edg receptors resulting in cell proliferation and cell migration. Interleukin‐8 (IL‐8) is a C‐X‐C chemokine and acts as a chemoattractant of neutrophils, whereas monocyte chemoattractant protein‐1 (MCP‐1) is a C‐C chemokine and functions mainly as a chemoattractant of monocytes/macrophages. Both factors are secreted from endothelial cells and have been implicated in the processes leading to atherosclerosis. We examined the effects of LPLs on the expression of IL‐8 and MCP‐1, key regulators of leukocyte recruitment in human umbilical cord vein endothelial cells (HUVECs). Work illustrated in this article showed that LPA and S1P enhanced IL‐8 and MCP‐1 mRNA expressions, and protein secretions in dose‐ and time‐dependent fashions. Maximal mRNA expression appeared at 16 hr post‐ligand treatment. Using prior treatments with chemical inhibitors, LPLs enhanced IL‐8 and MCP‐1 expressions through a Gi‐, Rho‐, and NFκB‐dependent mechanism. In a chemotaxis assay system, LPL treatments of endothelial cells enhanced monocyte recruitment through upregulating IL‐8 and MCP‐1 protein secretions. Pre‐incubation with AF12198, an IL‐1 receptor antagonist or IL‐1 functional blocking antibody both suppressed the enhanced effects elicited by LPLs of IL‐8 and MCP‐1 mRNA expressions in HUVECs. These results suggest that LPLs released by activated platelets might enhance the IL‐8‐ and MCP‐1‐dependent chemoattraction of monocytes toward the endothelium through an IL‐1‐dependent mechanism, which may play an important role in facilitating wound‐healing and inflammation processes. J. Cell. Biochem. 99: 1216–1232, 2006.

Molecular systematics and phylogeography of the gigantic earthworms of the Metaphire formosae species group (Clitellata, Megascolecidae)

The earthworms of the Metaphire formosae species group distributed in Taiwan are members of the Pheretima complex within the Megascolecidae. In this study, the systematics and phylogeography of this species group were investigated using DNA sequences of mitochondrial cytochrome c oxidase subunit I (COI), 16S ribosomal (r)RNA, and NADH dehydrogenase subunit 1 (ND1). The results indicated that the 13 taxa of the M. formosae species group form a clade, including a cryptic species discovered in this study. In addition, Metaphire hengchunensis (James, S.W., Shih, H.-T., Chang, H.-W., 2005. Seven new species of Amynthas (Clitellata: Megascolecidae) and new earthworm records from Taiwan. J. Nat. Hist. 39, 1007-1028) should be regarded as a subspecies of Metaphire paiwanna Tsai, C.-F., Shen, H.-P., Tsai, S.-C., 2000a. Native and exotic species of terrestrial earthworm (Oligochaeta) in Taiwan with reference to Northeast Asia. Zool. Stud. 39, 285-294, Tsai, C.-F., Tsai, S.-C., Liaw, G.-J., 2000b. Two new species of pontandric pheretimoid earthworms belonging to the genus Metaphire (Megascolecidae: Oligochaeta) from Taiwan. J. Nat. Hist. 34, 1731-1741, and Metaphire bununa glareosa Tsai et al. 2000 should be elevated to specific status. Phylogeographical inferences showed that allopatric speciation occurred in this species group during the rapid uplift of the main island of Taiwan between 5.0 and 2.5 million years ago. Our analysis exposes non-monophyly within each of the genera Amynthas and Metaphire, and more generally within the Pheretima complex. Further revisions of this speciose complex are urgently needed.

Lysophosphatidic acid induces reactive oxygen species generation by activating protein kinase C in PC-3 human prostate cancer cells

Prostate cancer is one of the most frequently diagnosed cancers in males, and PC-3 is a cell model popularly used for investigating the behavior of late stage prostate cancer. Lysophosphatidic acid (LPA) is a lysophospholipid that mediates multiple behaviors in cancer cells, such as proliferation, migration and adhesion. We have previously demonstrated that LPA enhances vascular endothelial growth factor (VEGF)-C expression in PC-3 cells by activating the generation of reactive oxygen species (ROS), which is known to be an important mediator in cancer progression. Using flow cytometry, we showed that LPA triggers ROS generation within 10min and that the generated ROS can be suppressed by pretreatment with the NADPH oxidase (Nox) inhibitor diphenylene iodonium. In addition, transfection with LPA1 and LPA3 siRNA efficiently blocked LPA-induced ROS production, suggesting that both receptors are involved in this pathway. Using specific inhibitors and siRNA, phospholipase C (PLC) and protein kinase C (PKC) were also suggested to participate in LPA-induced ROS generation. Overall, we demonstrated that LPA induces ROS generation in PC-3 prostate cancer cells and this is mediated through the PLC/PKC/Nox pathway.

Cloning, expression, and characterization of cadmium-induced metallothionein-2 from the earthworms Metaphire posthuma and Polypheretima elongata.

In this study we report the sequences of MT-2 cDNA from two species of Megascoleidae earthworms, Metaphire posthuma and Polypheretima elongata, by mRNA differential display after exposure of the organisms to cadmium. Complementary (c)DNA was verified as the MT-2 gene by the characteristics of its predicted translation product, namely a high cysteine content, conserved CXC motifs, and a molecular weight of around 8 kDa. Amino acid sequence alignment revealed a conserved TKCCG in the cloned MT-2 of both megascolecid earthworms instead of the corresponding conserved TQCCG found in lumbricid earthworms. The cDNAs corresponding to the two megascolecid MT-2 genes were expressed, and the MT-2 proteins were purified for biochemical characterization. The binding of Cu2+ exhibited monophasic kinetics and those of Zn2+ and Cd2+ biphasic kinetics. The proteins bound more tightly to Cd2+ than to Zn2+ and more tightly still to Cu2+. Zn-MT and apo-MT were the most effective at scavenging free radicals, followed by Cd-MT. In conclusion, MT-2s from M. posthuma and P. elongata showed unique sequence features compared to those of lumbricid earthworms. These earthworms could be used to evaluate heavy-metal pollution in soil due to the inducible MT-2 by cadmium exposure.

Photooxidation and antioxidant responses in the earthworm Amynthas gracilis exposed to environmental levels of ultraviolet B radiation.

Ultraviolet (UV) radiation leads to photooxidation in various organisms. Our previous study demonstrated that ultraviolet B (UV-B) radiation is lethal for particular species of earthworms, but the mechanisms responsible for the lethality are unclear. In our current study, we investigated that ultraviolet light causes photooxidative damage and reduces antioxidant responses in the earthworm Amynthas gracilis. Intact earthworms and skin/muscle tissue extracts were exposed to UV-B radiation for in vivo and in vitro studies. Both in vitro and in vivo results showed that the products of photooxidative damage, MDA and H(2)O(2), increased after UV-B exposure. Glutathione peroxidase (GPx) and catalase were inhibited immediately after exposure to high doses (3000J/m(2)) of UV-B radiation in vivo. Catalase activity was increased following a low UV-B dose (500J/m(2)) in vivo, but decreased in response to all dosage levels in vitro. These data indicate that a relationship exists between UV-B induced damage and photooxidation and also that catalase and GPx act as important antioxidants to prevent photooxidation. According to these data, A. gracilis exhibits high sensitivity to environmental levels of UV-B. Therefore, A. gracilis represents a sensitive and cost-effective model organism for investigations of UV-radiation damage and environmental UV stress.

The chemosensory ability of the predatory leech Whitmania laevis (Arhynchobdellida: Haemopidae) for prey searching

Although prey-detecting and searching abilities of predatory leeches of rhynchobdellid or the Erpobdelliformes of arhynchobdellid species have been studied in the past, hirudiniformes leeches are rarely mentioned. In this study, we investigated the chemosensory ability for prey-detecting and searching in Whitmania laevis, a hirudiniformes species that mainly preys on freshwater snails, and examined if such ability aided in their prey selection. Five sympatric snail species, i.e., apple snail Pomacea canaliculata, thiarid snail Thiara tuberculata, viviparid snail Sinotaia quadrata, ear pond snail Radix auricularia swinhoei and tadpole snail Physa acuta were used as prey. Our results showed that W. laevis has the chemosensory ability to detect the waterborne odors of snails. However, they follow the snails by their mucus trails, and not by the odor that the snails leave in the water. Of these five snail species, W. laevis only followed the trails of the thiarid snails, ear pond snails and tadpole snails, and did not show a different response to the trails produced by snails of different sizes. Our results suggest that W. laevis can use waterborne odors to detect the existence of prey. They rely on mucus trails to follow their preferred prey, but do not distinguish between snails of a preferred size by their mucus trails. In addition, when following the trail of a preferred snail, W. laevis exhibits a newly described searching behavior, i.e., head tapping, and may use it to locate a snail trail and increase its probability of finding the trail-laying snail nearby.

New species of earthworms belonging to the Metaphire formosae species group (Clitellata: Megascolecidae) in Taiwan

The Metaphire formosae species group is a member of the Pheretima complex of the family Megascolecidae. It is composed of 12 nominal taxa, Metaphire bununa Tsai et al., 2000, Metaphire feijani Chang & Chen, 2004, Metaphire formosae (Michaelsen, 1922), Metaphire glareosa Tsai et al., 2000, Metaphire nanaoensis Chang & Chen, 2005, Metaphire paiwanna paiwanna Tsai et al., 2000, Metaphire paiwanna hengchunensis (James et al., 2005), Metaphire paiwanna liliumfordi Tsai et al., 2000, Metaphire tahanmonta Chang & Chen, 2005, Metaphire taiwanensis Tsai et al., 2004, Metaphire trutina Tsai et al., 2003, and Metaphire yuhsi (Tsai, 1964). In this study, we describe a new species, Metaphire tengjhihensis sp. nov., and two new subspecies, Metaphire nanaoensis truku ssp. nov. and Metaphire taiwanensis tsaii ssp. nov., belonging to this species group. DNA barcodes (partial sequences of the mitochondrial cytochrome c oxidase subunit 1, COI) from type specimens of M. feijani, M. tengjhihensis sp. nov., M. nanaoensis truku ssp. nov., M. tahanmonta and M. taiwanensis tsaii ssp. nov. have been deposited in GenBank in previous studies and are explicitly linked to the type specimens for the first time, enabling unambiguous identification using both morphology and DNA barcodes. Finally, we comment on the systematics of the M. formosae species group and suggest an integrative taxonomic approach that combines morphology and DNA barcodes for future descriptions of new species of Amynthas and Metaphire.

A New Record of the Octochaetid Earthworm Dichogaster affinis (Michaelsen, 1890) from the Centro-western Taiwan

This paper describes the octochaetid earthworm Dichogaster affinis (Michaelsen, 1890) as a new record from the centro-western Taiwan. It is a small earthworm with two gizzards, belonging to the family Octochaetidae. D. affinis is quadriprostatic and has a pair of female pores in XIV and genital markings in 7/8-9/10. It is easily distinguishable from other two congeneric species in Taiwan, Dichogaster saliens (Beddard, 1892) that is biprostatic and Dichogaster bolaui (Michaelsen, 1891) that is quadriprostatic but has a single female pore and no genital marking. Occurrence of D. affinis in Taiwan reported herein constitutes the island as the northernmost range of this cosmopolitan species in East Asia.

Species composition of earthworms on the main campus of National Taiwan University

In our study, 14 species of earthworms, belonging to two families and four genera, were found on the National Taiwan University (NTU) main campus. Most of them have been recorded in Taiwan except for Amynthas papilio and two unknown species (Amynthas spp.). Five species namely A. corticus, A. gracilis, A. robustus, Metaphire californica, and Pontoscolex corethrurus are widely distributed on the campus. In a comparison of earthworm species recorded at NTU in 1964, three species were not collected this time, and seven species were found for the first time on the campus. Because the low level of development of the NTU main campus would tend to conserve most earthworm species, it can serve as a good reservoir for earthworms in the Taipei area. The web site of The earthworm guide to the NTU main campus (http://earthworm.zo.ntu.edu.tw/NTUearthworm) displays the data of this study in detail with an active format.