Bioactive Secondary Metabolites Isolated from the Antarctic Lichen Himantormia lugubris.

Two new depsidones, himantormiones A and B (1 and 2) were isolated and identified from the Antarctic lichen, Himantormia lugubris (Parmeliaceae), with seven known compounds (3-9). The structures of two new compounds (1 and 2) were determined by means of spectroscopic analyses, including 1D and 2D NMR and HR-MS. The isolated compounds were tested for antimicrobial and cytotoxic activities, where himantormione B (2) exhibited inhibitory effect against Staphylococcus aureus with the IC50 value of 7.01±0.85 mM. Compound 2 also exhibited strong cytotoxic activity against HCT116 cells (colon cancer) with the EC50 value of 1.11±0.85 µM, where that of the positive control, 5-fluouracil, was 9.4±1.90 µM.

Bioactive Terphenyls Isolated from the Antarctic Lichen Stereocaulon alpinum.

Three p-terphenyls (2-4)-2-hydroxy-3,5-dimethoxy-p-terphenyl (2), 2-hydroxy-3,6-dimethoxy-p-terphenyl (3), and 2,3,5,6-tetramethoxy-p-terphenyl (4)-were isolated for the first time as natural products along with seven known compounds (1, 5-10) from the Antarctic lichen Stereocaulon alpinum. Structures of the new compounds were elucidated by comprehensive analyses of 1D and 2D NMR and HREIMS experiments. Compound 3 exhibited cytotoxicity against HCT116 cells with the IC50 value of 3.76 ± 0.03 µM and also inhibited NO production in LPS-induced RAW264.7 macrophages with the IC50 value of 22.82 ± 0.015 µM.

Fhit induces the reciprocal suppressions between Lin28/Let-7 and miR-17/92miR.

Objective: Fhit gene is known as a genome "caretaker" and frequently inactivated by deletion or hypermethylation on the promoter in several cancers. In spite of several lines of evidence, the exact mechanism underlying Fhit-induced biology is relatively less studied. This study will focus the role of Fhit in regulating Lin28 and microRNAs (miRNAs) loop. Material and Methods: To this end, we employed Fhit overexpressing isogenic cell lines to conduct miRNA nanostring array, and differentially expressed miRNAs were identified. Using real-time PCR and Western blot analysis, expression levels of Lin28b or miRNAs were investigated in response to the overexpression of Fhit gene in H1299 lung cancer cells. Results: A series of in vitro including gene nanostring analyses revealed that Lin28B protein was induced by Fhit gene overexpression, which consequently suppressed Let-7 miRNAs. Also, we found that miRNAs in miR-17/92 clusters are redundantly increased and there is an inverse correlation between Let-7 and miR-17/92 clusters in Fhit-expressing cells. Also, a series of in vitro experiments suggests that ELF-1- and/or STAT1-dependent Lin28b regulation is responsible for Let-7 induction in Fhit-expressing cancer cells. Conclusions: Based on the same experimental system proving that Fhit gene has a robust role in suppressing tumor progression and epithelial-mesenchymal transition, our data show that Fhit mediates the negative feedback between Lin28/Let-7 axis and miR-17/-92 miRNA although the physiological relevance of current interesting observation should be further investigated.

Anticancer Activity of 2-O-caffeoyl Alphitolic Acid Extracted from the Lichen, Usnea barbata 2017-KL-10.

Colorectal cancer is one of the life-threatening ailments causing high mortality and morbidity worldwide. Despite the innovation in medical genetics, the prognosis for metastatic colorectal cancer in patients remains unsatisfactory. Recently, lichens have attracted the attention of researchers in the search for targets to fight against cancer. Lichens are considered mines of thousands of metabolites. Researchers have reported that lichen-derived metabolites demonstrated biological effects, such as anticancer, antiviral, anti-inflammatory, antibacterial, analgesic, antipyretic, antiproliferative, and cytotoxic, on various cell lines. However, the exploration of the biological activities of lichens' metabolites is limited. Thus, the main objective of our study was to evaluate the anticancer effect of secondary metabolites isolated from lichen (Usnea barbata 2017-KL-10) on the human colorectal cancer cell line HCT116. In this study, 2OCAA exhibited concentration-dependent anticancer activities by suppressing antiapoptotic genes, such as MCL-1, and inducing apoptotic genes, such as BAX, TP53, and CDKN1A(p21). Moreover, 2OCAA inhibited the migration and invasion of colorectal cancer cells in a concentration-dependent manner. Taken together, these data suggest that 2OCAA is a better therapeutic candidate for colorectal cancer.

Antarctic freshwater microalga, Chloromonas reticulata, suppresses inflammation and carcinogenesis.

Inflammation triggered by the innate immune system is a strategy to protect organisms from the risk of environmental infection. However, it has recently become clear that inflammation can cause a variety of human diseases, including cancer. In this study, we investigated the effects of an ethanol extract of the Antarctic freshwater microalgae, Chloromonas reticulata (ETCH), on inflammation and carcinogenesis in RAW 264.7 macrophages and HCT116 human colon cancer cells, respectively. ETCH exhibited significant anti-inflammatory activity through the dose-dependent modulation of major inflammatory markers such as COX-2, IL-6, iNOS, TNF-α, and NO production. For example, ETCH reduced LPS-induced upregulation of COX-2, IL-6, iNOS, and TNF- alpha mRNA levels, leading to a significant decrease in the levels of LPS-stimulated NO and IL-6 as well as TNF-alpha products. In contract, ETCH exhibited dose-dependent cytotoxic activity against HCT116 cells, yielding a profound reduction in the proliferation of the cancer cells. Furthermore, ETCH induced G2 phase cell cycle arrest by transcriptionally regulating of genes involved in G2 / M transition including p21 (CDKN1A), cyclin B1 (CCNB1), and CDK1; CDKN1A mRNA levels were upregulated in response to ETCH, whereas CCNB1 and CDK1 were downregulated. This study reports for the first time anti-inflammatory and anti-cancer effects of, C. reticulata and provides new insights into the molecular mechanisms of the linkage between inflammation and cancer.

The Comprehensive Roles of ATRANORIN, A Secondary Metabolite from the Antarctic Lichen Stereocaulon caespitosum, in HCC Tumorigenesis.

Hepatocellular carcinoma (HCC) is one of the most deadly genetic diseases, but surprisingly chemotherapeutic approaches against HCC are only limited to a few targets. In particular, considering the difficulty of a chemotherapeutic drug development in terms of cost and time enforces searching for surrogates to minimize effort and maximize efficiency in anti-cancer therapy. In spite of the report that approximately one thousand lichen-derived metabolites have been isolated, the knowledge about their functions and consequences in cancer development is relatively limited. Moreover, one of the major second metabolites from lichens, Atranorin has never been studied in HCC. Regarding this, we comprehensively analyze the effect of Atranorin by employing representative HCC cell lines and experimental approaches. Cell proliferation and cell cycle analysis using the compound consistently show the inhibitory effects of Atranorin. Moreover, cell death determination using Annexin-V and (Propidium Iodide) PI staining suggests that it induces cell death through necrosis. Lastly, the metastatic potential of HCC cell lines is significantly inhibited by the drug. Taken these together, we claim a novel functional finding that Atranorin comprehensively suppresses HCC tumorigenesis and metastatic potential, which could provide an important basis for anti-cancer therapeutics.

Anti-inflammation and Anti-Cancer Activity of Ethanol Extract of Antarctic Freshwater Microalga, Micractinium sp.

Inflammation mediated by the innate immune system is an organism's protective mechanism against infectious environmental risk factors. It is also a driver of the pathogeneses of various human diseases, including cancer development and progression. Microalgae are increasingly being focused on as sources of bioactive molecules with therapeutic potential against various diseases. Furthermore, the antioxidant, anti-inflammatory, and anticancer potentials of microalgae and their secondary metabolites have been widely reported. However, the underlying mechanisms remain to be elucidated. Therefore, in this study, we investigated the molecular mechanisms underlying the anti-inflammatory and anticancer activities of the ethanol extract of the Antarctic freshwater microalga Micractinium sp. (ETMI) by several in vitro assays using RAW 264.7 macrophages and HCT116 human colon cancer cells. ETMI exerted its anti-inflammatory activity by modulating the main inflammatory indicators such as cyclooxygenase (COX)-2, interleukin (IL)-6, inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-α, and nitric oxide (NO) in a dose-dependent manner. In addition, ETMI exerted cytotoxic activity against HCT116 cells in a dose-dependent manner, leading to significantly reduced cancer cell proliferation. Further, it induced cell cycle arrest in the G1 phase through the regulation of hallmark genes of the G1/S phase transition, including CDKN1A, and cyclin-dependent kinase 4 and 6 (CDK4 and CDK6, respectively). At the transcriptional level, the expression of CDKN1A gradually increased in response to ETMI treatment while that of CDK4 and CDK6 decreased. Taken together, our findings suggest that the anti-inflammatory and anticancer activities of the Antarctic freshwater microalga, Micractinium sp., and ETMI may provide a new clue for understanding the molecular link between inflammation and cancer and that ETMI may be a potential anticancer agent for targeted therapy of colorectal cancer.

Anti-Cancer Activity of Lobaric Acid and Lobarstin Extracted from the Antarctic Lichen Stereocaulon alpnum.

Lobaric acid and lobarstin, secondary metabolites derived from the antarctic lichen Stereocaulon alpnum, exert various biological activities, including antitumor, anti-proliferation, anti-inflammation, and antioxidant activities. However, the underlying mechanisms of these effects have not yet been elucidated in human cervix adenocarcinoma and human colon carcinoma. In the present study, we evaluated the anticancer effects of lobaric acid and lobarstin on human cervix adenocarcinoma HeLa cells and colon carcinoma HCT116 cells. We show that the proliferation of Hela and HCT116 cells treated with lobaric acid and lobarstin significantly decreased in a dose- and time-dependent manner. Using flow cytometry analysis, we observed that the treatment with these compounds resulted in significant apoptosis in both cell lines, following cell cycle perturbation and arrest in G2/M phase. Furthermore, using immunoblot analysis, we investigated the expression of cell cycle and apoptosis-related marker genes and found a significant downregulation of the apoptosis regulator B-cell lymphoma 2 (Bcl-2) and upregulation of the cleaved form of the poly (ADP-ribose) polymerase (PARP), a DNA repair and apoptosis regulator. These results suggest that lobaric acid and lobarstin could significantly inhibit cell proliferation through cell cycle arrest and induction of apoptosis via the mitochondrial apoptotic pathway in cervix adenocarcinoma and colon carcinoma cells. Taken together, our data suggests that lobaric acid and lobarstin might be novel agents for clinical treatment of cervix adenocarcinoma and colon carcinoma.

Bioactivities of ethanol extract from the Antarctic freshwater microalga, Chloromonas sp.

Cancer is the principal cause of human death and occurs through highly complex processes that involve the multiple coordinated mechanisms of tumorigenesis. A number of studies have indicated that the microalgae extracts showed anticancer activity in a variety of human cancer cells and can provide a new insight in the development of novel anti-cancer therapy. Here, in order to investigate molecular mechanisms of anticancer activity in the Antarctic freshwater microalga, Chloromonas sp., we prepared ethanol extract of Chloromonas sp. (ETCH) and performed several in vitro assays using human normal keratinocyte (HaCaT) and different types of cancer cells including cervical, melanoma, and breast cancer cells (HeLa, A375 and Hs578T, respectively). We revealed that ETCH had the antioxidant capacity, and caused significant cell growth inhibition and apoptosis of cancer cells in a dose-dependent manner, whereas it showed no anti-proliferation to normal cells. In addition, ETCH had a significant inhibitory effect on cell invasion without the cytotoxic effect. Furthermore, ETCH-induced apoptosis was mediated by increase in pro-apoptotic proteins including cleaved caspase-3 and p53, and by decrease in anti-apoptotic protein, Bcl-2 in ETCH-treated cancer cells. Taken together, this work firstly explored the antioxidant and anticancer activities of an Antarctic freshwater microalga, and ETCH could be a potential therapeutic candidate in the treatment of human cancer.

Comprehensive Expression Profiling and Functional Network Analysis of Porphyra-334, One Mycosporine-Like Amino Acid (MAA), in Human Keratinocyte Exposed with UV-radiation.

Mycosporine-like amino acids (MAAs) have been highlighted as pharmacologically active secondary compounds to protect cells from harmful UV-radiation by absorbing its energy. Previous studies have mostly focused on characterizing their physiological properties such as antioxidant activity and osmotic regulation. However, molecular mechanisms underlying their UV-protective capability have not yet been revealed. In the present study, we investigated the expression profiling of porphyra-334-modulated genes or microRNA (miRNAs) in response to UV-exposure and their functional networks, using cDNA and miRNAs microarray. Based on our data, we showed that porphyra-334-regulated genes play essential roles in UV-affected biological processes such as Wnt (Wingless/integrase-1) and Notch pathways which exhibit antagonistic relationship in various biological processes; the UV-repressed genes were in the Wnt signaling pathway, while the activated genes were in the Notch signaling. In addition, porphyra-334-regulated miRNAs can target many genes related with UV-mediated biological processes such as apoptosis, cell proliferation and translational elongation. Notably, we observed that functional roles of the target genes for up-regulated miRNAs are inversely correlated with those for down-regulated miRNAs; the former genes promote apoptosis and translational elongation, whereas the latter function as inhibitors in these processes. Taken together, these data suggest that porphyra-334 protects cells from harmful UV radiation through the comprehensive modulation of expression patterns of genes involved in UV-mediated biological processes, and that provide a new insight to understand its functional molecular networks.

FHIT suppresses epithelial-mesenchymal transition (EMT) and metastasis in lung cancer through modulation of microRNAs.

Metastasis is the principal cause of cancer death and occurs through multiple, complex processes that involve the concerted action of many genes. A number of studies have indicated that the Fragile Histidine Triad (FHIT) gene product, FHIT, functions as a tumor suppressor in a variety of common human cancers. Although there are suggestions of a role for FHIT loss in progression of various cancers, a role for such loss in metastasis has not been defined. Here, via in vivo and in vitro assays, we reveal that the enforced expression of FHIT significantly suppresses metastasis, accompanied by inhibition of the epithelial-mesenchymal transition (EMT), a process involved in metastasis through coordinate modulation of EMT-related genes. Specifically, miR-30c, a FHIT-upregulated microRNA, contributes to FHIT function in suppression of EMT and metastasis by directly targeting metastasis genes Metadherin (MTDH), High-mobility group AT-hook 2 (HMGA2), and the mesenchymal markers, Vimentin (VIM) and Fibronectin (FN1), in human lung cancer. Finally, we demonstrate that the expression pattern of FHIT and miR-30c is inversely correlated with that of MTDH and HMGA2 in normal tissue, non-metastatic and metastatic tumors, serving as a potential biomarker for metastasis in lung cancer.

Anticancer activities of ethanol extract from the Antarctic freshwater microalga, Botryidiopsidaceae sp.

BACKGROUND: Cancer is a leading cause of human death around the world and occurs through the highly complex coordination of multiple cellular pathways. Recent studies have revealed that microalgal extracts exhibit considerable pharmaceutical activities, including those against various cancer cells. Thus, microalgae are promising candidates as novel cancer therapeutic drugs. In this study, we evaluated the biological functions of the ethanolic extract of the Antarctic freshwater microalga, Bo tryidiopsidaceae sp., such as its antioxidant, anti-proliferative, apoptotic and anti-invasive properties. METHODS: To estimate antioxidant capacity of ethanol extract of Bo tryidiopsidaceae sp. (ETBO), free radical 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used. The anti-proliferative activity of ETBO was assessed in several cancer cell lines (A375, Hs578T and HeLa) and non-tumorigenic keratinocyte cells (HaCaT), using MTT assay. In addition, Annexin V binding was performed to detect ETBO-induced apoptotic cells, and the expression levels of apoptosis-regulating proteins, caspase-3, p53, and Bcl-2, were determined by western blot. Boyden chamber assays were used to determine anti-migratory and anti-invasive properties of ETBO. RESULTS: ETBO exhibited antioxidant activity and concentration-dependent anticancer activities, such as anti-proliferation and pro-apoptotic activities against cancer cells. Furthermore, the expression of the apoptosis-inducing proteins, p53 and caspase-3, significantly increased in response to ETBO, whereas the expression of the anti-apoptotic protein, Bcl-2, decreased. These data imply that ETBO induces apoptosis by caspase activation through the modulation of pro-apoptotic and anti-apoptotic gene, p53 and Bcl-2, respectively. In addition, ETBO significantly inhibited migration and invasion of cervical cancer cells in a concentration-dependent manner. CONCLUSION: In this study, ETBO exhibited considerable anticancer activities, such as inhibition of proliferation, invasion, and migration, as well as induction of apoptosis. These data suggest that ETBO is a promising therapeutic agent in cancer therapy and drug discovery.

Differential gene expression patterns during embryonic development of sea urchin exposed to triclosan.

Triclosan (TCS; 2,4,4'-trichloro-2'-hydroxydiphenyl ether) is a broad-spectrum antibacterial agent used in common industrial, personal care and household products which are eventually rinsed down the drain and discharged with wastewater effluent. It is therefore commonly found in the aquatic environment, leading to the continual exposure of aquatic organisms to TCS and the accumulation of the antimicrobial and its harmful degradation products in their bodies. Toxic effects of TCS on reproductive and developmental progression of some aquatic organisms have been suggested but the underlying molecular mechanisms have not been defined. We investigated the expression patterns of genes involved in the early development of TCS-treated sea urchin Strongylocentrotus nudus using cDNA microarrays. We observed that the predominant consequence of TCS treatment in this model system was the widespread repression of TCS-modulated genes. In particular, empty spiracles homeobox 1 (EMX-1), bone morphogenic protein, and chromosomal binding protein genes showed a significant decrease in expression in response to TCS. These results suggest that TCS can induce abnormal development of sea urchin embryos through the concomitant suppression of a number of genes that are necessary for embryonic differentiation in the blastula stage. Our data provide new insight into the crucial role of genes associated with embryonic development in response to TCS. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 426-433, 2017.

Anticancer Activity of Ramalin, a Secondary Metabolite from the Antarctic Lichen Ramalina terebrata, against Colorectal Cancer Cells.

Colorectal cancer is a leading cause of death worldwide and occurs through the highly complex coordination of multiple cellular pathways, resulting in carcinogenesis. Recent studies have increasingly revealed that constituents of lichen extracts exhibit potent pharmaceutical activities, including anticancer activity against various cancer cells, making them promising candidates for new anticancer therapeutic drugs. The main objective of this study was to evaluate the anticancer capacities of ramalin, a secondary metabolite from the Antarctic lichen Ramalina terebrata, in the human colorectal cancer cell line HCT116. In this study, ramalin displayed concentration-dependent anticancer activity against HCT116 cells, significantly suppressing proliferation and inducing apoptosis. Furthermore, ramalin induced cell cycle arrest in the gap 2/mitosis (G2/M) phase through the modulation of hallmark genes involved in the G2/M phase transition, such as tumour protein p53 (TP53), cyclin-dependent kinase inhibitor 1A (CDKN1A), cyclin-dependent kinase 1 (CDK1) and cyclin B1 (CCNB1). At both the transcriptional and translational level, ramalin caused a gradual increase in the expression of TP53 and its downstream gene CDKN1A, while decreasing the expression of CDK1 and CCNB1 in a concentration-dependent manner. In addition, ramalin significantly inhibited the migration and invasion of colorectal cancer cells in a concentration-dependent manner. Taken together, these data suggest that ramalin may be a therapeutic candidate for the targeted therapy of colorectal cancer.

Detection of the dinoflagellate, Cochlodinium polykrikoides, that forms algal blooms using sandwich hybridization integrated with nuclease protection assay.

OBJECTIVES: To detect Cochlodinum polykrikoides in long-term monitoring and high-throughput sampling projects using an integrated sandwich hybridization and nuclease protection assay (NPA-SH). RESULTS: The specificity of the probes was verified with individual and mixed cultures as well as field collection, and the quantity of C. polykrikoides determined by NPA-SH analysis showed a good correlation with that determined by cell-counting with a light microscope. In addition a standard curve for C. polykrikoides was established to represent the correlation between optical absorbance in the NPA-SH assay and cell density. CONCLUSIONS: This approach provides an efficient alternative to traditional, morphology-based methods for the rapid identification and quantification of harmful algal species and could be used to monitor phytoplankton in field surveys.

The expression of microRNA-34a is inversely correlated with c-MET and CDK6 and has a prognostic significance in lung adenocarcinoma patients.

We aimed to establish whether the expression of microRNA-34a (miR-34a) is correlated with that of c-MET and G1 phase regulators such as cyclin dependent kinase (CDK) 4, CDK6, and cyclin D (CCND) 1 in non-small cell lung cancer (NSCLC), and whether a relationship exists between miR-34a expression and both clinicopathologic factors and recurrence-free survival (RFS). For 58 samples archived from NSCLC patients, we measured the expression of miR-34a and c-MET, CDK4/6, and CCND1 by quantitative RT-PCR and assessed the relationship between miR-34a expression, clinicopathological factors, and RFS. The expression of miR-34a was significantly lower in squamous cell tumors (P < 0.001) and in tumors associated with lymphatic invasion (P = 0.001). We found significant inverse correlations between miR-34a and c-MET (R = -0.316, P = 0.028) and CDK6 expression (R = -0.4582, P = 0.004). RFS were longer in adenocarcinoma patients with high miR-34a expression than in those with low miR-34a expression (55.6 vs. 21.6 months; P = 0.020). With univariate analysis, statistically significant prognostic factors for RFS in adenocarcinoma patients were miR-34a expression (Relative risk (RR), 8.14; P = 0.049), TNM stage (RR, 13.55; P = 0.001), LN metastasis (RR, 4.19; P = 0.043), and the presence of lymphatic invasion (RR, 7.05; P = 0.015). In multivariate analysis, only miR-34a was prognostic for RFS (RR, 11.5; P = 0.027). miR-34a expression was inversely correlated with that of c-MET and CDK6 in NSCLC, and had prognostic significance for RFS, especially in adenocarcinoma patients.

MicroRNAs/TP53 feedback circuitry in glioblastoma multiforme.

MicroRNAs (miRNAs) are increasingly implicated in regulating cancer initiation and progression. In this study, two miRNAs, miR-25 and -32, are identified as p53-repressed miRNAs by p53-dependent negative regulation of their transcriptional regulators, E2F1 and MYC. However, miR-25 and -32 result in p53 accumulation by directly targeting Mdm2 and TSC1, which are negative regulators of p53 and the mTOR (mammalian target of rapamycin) pathway, respectively, leading to inhibition of cellular proliferation through cell cycle arrest. Thus, there is a recurrent autoregulatory circuit involving expression of p53, E2F1, and MYC to regulate the expression of miR-25 and -32, which are miRNAs that, in turn, control p53 accumulation. Significantly, overexpression of transfected miR-25 and -32 in glioblastoma multiforme cells inhibited growth of the glioblastoma multiforme cells in mouse brain in vivo. The results define miR-25 and -32 as positive regulators of p53, underscoring their role in tumorigenesis in glioblastoma.

Anti-inflammation activities of mycosporine-like amino acids (MAAs) in response to UV radiation suggest potential anti-skin aging activity.

Certain photosynthetic marine organisms have evolved mechanisms to counteract UV-radiation by synthesizing UV-absorbing compounds, such as mycosporine-like amino acids (MAAs). In this study, MAAs were separated from the extracts of marine green alga Chlamydomonas hedleyi using HPLC and were identified as porphyra-334, shinorine, and mycosporine-glycine (mycosporine-Gly), based on their retention times and maximum absorption wavelengths. Furthermore, their structures were confirmed by triple quadrupole MS/MS. Their roles as UV-absorbing compounds were investigated in the human fibroblast cell line HaCaT by analyzing the expression levels of genes associated with antioxidant activity, inflammation, and skin aging in response to UV irradiation. The mycosporine-Gly extract, but not the other MAAs, had strong antioxidant activity in the 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. Furthermore, treatment with mycosporine-Gly resulted in a significant decrease in COX-2 mRNA levels, which are typically increased in response to inflammation in the skin, in a concentration-dependent manner. Additionally, in the presence of MAAs, the UV-suppressed genes, procollagen C proteinase enhancer (PCOLCE) and elastin, which are related to skin aging, had increased expression levels equal to those in UV-mock treated cells. Interestingly, the increased expression of involucrin after UV exposure was suppressed by treatment with the MAAs mycosporine-Gly and shinorine, but not porphyra-334. This is the first report investigating the biological activities of microalgae-derived MAAs in human cells.

Effects of triclosan on reproductive prarmeters and embryonic development of sea urchin, Strongylocentrotus nudus.

Triclosan (TCS, 2,4,4'-trichloro-2'-hydroxydiphenyl ether), a broad-spectrum antibacterial agent, is commonly found in the aquatic environment. In this study, we investigated TCS toxicity with pertaining to gamete viability, fertilization, and embryogenesis up to pluteus stage of the sea urchin, (Strongylocentrotus nudus). When the sperm and eggs were exposed to TCS (0-3.0 µM), the viability of sperm was significantly decreased at molarities higher than 1 µM of TCS. In addition, for exposure of 2.0 µM TCS the viability of eggs was not influenced and none of the sperm was viable. Fertilization rate was significantly decreased when sperm were exposed to 0.5 and 1 µM of TCS (p<0.001) and no fertilization was observed for the exposure of 1.5 µM of TCS. In embryonic development, embryos are treated with higher than 1.0 µM levels of TCS displayed arrested development. For TCS, the EC50 and LOECs values were 1.8, 1.49 and 0.99 µM and 0.53, 0.62 and 0.39 µM for sperm viability, fertilization rate, and larval development to pluteus, respectively. In the recovery test regarding normal development of arrested embryos based upon TCS exposure time, it was observed that embryos exposed to 1 µM TCS for 15 h were normally recovered for normal development, while embryos with more than 30 h exposure were not recovered to normal larvae. Overall, the results of this study strongly suggest that the gametes and embryos of S. nudus can provide the basis for an effective bioassay, with a fast and sensitive means of evaluating TCS contamination in the marine ecosystem.

Hypoxia-modulated gene expression profiling in sea urchin (Strongylocentrotus nudus) immune cells.

Hypoxia is an issue that affects ocean coastal waters worldwide. It has severe consequences for marine organisms, including death and rapid adaptive changes in metabolic organization. Although some aquatic animals are routinely exposed and resistant to severe environmental hypoxia, others such as sea urchins (Strongylocentrotus nudus) have a limited capacity to withstand this stress. In this study, hypoxia induced a significant increase in the number of red spherule cells among coelomocytes, which function as immune cells. This suggests that sea urchin immune cells could be used as a biological indicator of hypoxic stress. In the current study, we used cDNA microarrays to investigate the differential expression patterns of hypoxia-regulated genes to better understand the molecular mechanisms underlying the response of immune cells to hypoxia. Surprisingly, the predominant major effect of hypoxia was the widespread suppression of gene expression. In particular, the expression of RNA helicase and GATA-4/5/6 was decreased significantly in response to hypoxia, even in field conditions, suggesting that they could be utilized as sensitive bioindicators of hypoxic stress in the sea urchin.