Growth and domoic acid content of Pseudo-nitzschia australis isolated from northwestern Baja California,Mexico, cultured under batch conditions at different temperatures and two Si:NO3 ratios

Domoic acid (DA) poisoning in the southern part of the California Current System has been associated typically with blooms of Pseudo-nitzschia australis. The environmental variables that promote growth and DA production in the Mexican part of this system have not been identified. The present study investigated the effect of temperature and two nutrient ratios on the growth characteristics and DA content of two (BTS-1, BTS-2) P. australis strains isolated from the Pacific coast of northern Baja California peninsula, México. Of the different temperatures assayed (10, 12, 14, 15, 18 and 20 °C), the maximum cell abundance was detected at 12 °C for BTS-2 and 14 °C for BTS-1. The highest maximum specific growth rate (1.69 day⁻¹) was measured at 15 °C for BTS-2. With the exception of cells maintained at 15 °C, growth characteristics were similar in P. australis cultured in a high Si:NO₃ (2.5) or low Si:NO₃ (0.5) ratio at each temperature. Dissolved (dDA) and cellular (cDA) DA content measured at the stationary phase of growth was similar in cells cultivated at the different temperatures. No difference in cDA (between 0.11 and 1.87 pg DA cell⁻¹) was observed in cells cultivated at the two nutrient ratios. To evaluate if P. australis accumulates DA (cDA + dDA) at different stages of the culture and not only during the stationary phase of growth, the BTS-1 strain was cultivated at 14 °C and the content of this toxin was measured during culture development. The cultures were maintained at high (HL; 200 μmol quanta m⁻² s⁻¹) and low light (LL; 30 μmol quanta m⁻² s⁻¹) and in the two nutrient ratios to evaluate the effect of these variables on DA content. The photosynthetic performance and pigment concentration were measured as indicators of the physiological condition of the cells. cDA was detected in all culture conditions and during the different stages of growth. The highest DA content was measured during the lag phase of growth and it was present mainly in the medium (dDA = 70.83 pg DA cell⁻¹). Cells cultivated at HL produced more DA than LL cultured cells. P. australis cultured in HL presented lower photosynthetic rates than LL cells and had similar concentrations of photoprotective pigments and the highest maximum photosynthetic rates were detected during the lag phase of growth in all culture conditions. The results demonstrate that P. australis from northern Baja California peninsula presents a narrow temperature range for optimal growth under batch culture conditions. P. australis produce DA at different stages of growth, and DA content was related to the light intensity at which the cells were cultivated.     

Resveratrol and curcumin synergistically induces apoptosis in cigarette smoke condensate transformed breast epithelial cells through a p21Waf1/Cip1 mediated inhibition of Hh-Gli signaling

Combination therapy using two or more small molecule inhibitors of aberrant signaling cascade in aggressive breast cancers is a promising therapeutic strategy over traditional monotherapeutic approaches. Here, we have studied the synergistic mechanism of resveratrol and curcumin induced apoptosis using in vitro (cigarette smoke condensate mediated transformed breast epithelial cell, MCF-10A-Tr) and in vivo (tumor xenograft mice) model system. Resveratrol exposure increased the intracellular uptake of curcumin in a dose dependent manner and caused apoptosis in MCF-10A-Tr cells. Approximately, ten fold lower IC₅₀ value was noted in cells treated with the combination of resveratrol (3 μM) and curcumin (3 μM) in comparison to 30 μM of resveratrol or curcumin alone. Resveratrol + curcumin combination caused apoptosis by increasing Bax/Bcl-xL ratio, Cytochrome C release, cleaved product of PARP and caspase 3 in cells. Interestingly, this combination unaltered the protein expressions of WNT-TCF and Notch signaling components, β-catenin and cleaved notch-1 val1744, respectively. Furthermore, the combination also significantly decreased the intermediates of Hedgehog-Gli cascade including SMO, SHH, Gli-1, c-MYC, Cyclin-D1, etc. and increased the level of p21^Waf/Cip1 in vitro and in vivo. A significant reduction of Gli- promoter activity was noted in combinational drug treated cells in comparison to individual drug treatment. Un-alteration of the expressions of the above proteins and Gli1 promoter activity in p21^Waf/Cip1 knockout cells suggests this combination caused apoptosis through p21^Waf/Cip1. Thus, our findings revealed resveratrol and curcumin synergistically caused apoptosis in cigarette smoke induced breast cancer cells through p2  ^Waf/Cip1 mediated inhibition of Hedgehog-Gli cascade.     

Synthesis,molecular docking and evaluation of thiazolyl-pyrazoline derivatives containing benzodioxole as potential anticancer agents

A series of novel thiazolyl-pyrazoline derivatives containing benzodioxole (C1–C20) have been designed and synthesized. Among of the synthesized compounds, 2-(5-(benzo[d][1,3]dioxol-5-yl)-3-(4-bromophenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-bromophenyl)thiazole (C6) displayed the most potent inhibitory activity for HER-2 (IC₅₀ = 0.18 μM for HER-2). Antiproliferative assay results indicated that compound C6 owned high antiproliferative activity against MCF-7 and B16-F10 in vitro, with IC₅₀ value of 0.09 and 0.12 μM, respectively, being comparable with the positive control Erlotinib. Docking simulation was further performed to determine the probable binding model. Based on the preliminary results, compound C6 with potent inhibitory activity in tumor growth would be a potential anticancer agent.     

Antifungal saponins from bulbs of white onion,Allium cepa L.

Three saponins, named ceposide A, ceposide B, and ceposide C were isolated from the bulbs of white onion, Allium cepa L. Elucidation of their structure was carried out by comprehensive spectroscopic analyses, including 2D NMR spectroscopy and mass spectrometry, and chemical evidences. The structures of the compounds were identified as (25R)-furost-5(6)-en-1β,3β,22α,26-tetraol 1-O-β-d-xylopyranosyl 26-O-α-d-rhamnoyranosyl-(1 → 2)-O-β-d-galactopyranoside (ceposide A), (25R)-furost-5(6)-en-1β,3β,22α,26-tetraol 1-O-β-d-xylopyranosyl 26-O-α-d-rhamnoyranosyl-(1 → 2)-O-β-d-glucopyranoside (ceposide B), and (25R)-furost-5(6)-en-1β,3β,22α,26-tetraol 1-O-β-d-galactopyranosyl 26-O-α-d-rhamnoyranosyl-(1 → 2)-O-β-d-galactopyranoside (ceposide C). The isolated compounds, alone and in combinations, were evaluated for their antimicrobial activity on ten fungal species. Antifungal activity of all three saponins increased with their concentration and varied with the following rank: ceposide B > ceposide A–ceposide C. We found a significant synergism in the antifungal activity of the three ceposides against Botrytis cinerea and Trichoderma atroviride, because growth of these fungi was strongly inhibited when the three saponins were applied in combination. In contrast, Fusarium oxysporum f. sp. lycopersici, Sclerotium cepivorum and Rhizoctonia solani were very little affected by saponins.     

Marine snow formation by the toxin-producing diatom,Pseudo-nitzschia australis

The formation of marine snow (MS) by the toxic diatom Pseudo-nitschia australis was simulated using a roller table experiment. Concentrations of particulate and dissolved domoic acid (pDA and dDA) differed significantly among exponential phase and MS formation under simulated near surface conditions (16 °C/12:12-dark:light cycle) and also differed compared to subsequent particle decomposition at 4 °C in the dark, mimicking conditions in deeper waters. Particulate DA was first detected at the onset of exponential growth, reached maximum levels associated with MS aggregates (1.21 ± 0.24 ng mL⁻¹) and declined at an average loss rate of ∼1.2% pDA day⁻¹ during particle decomposition. Dissolved DA concentrations increased throughout the experiment and reached a maximum of ∼20 ng mL⁻¹ at final sampling on day 88. The succession by P. australis from active growth to aggregation resulted in increasing MS toxicity and based on DA loading of particles and known in situ sinking speeds, a significant amount of toxin could have easily reached the deeper ocean or seafloor. MS formation was further associated with significant dDA accumulation at a ratio of pDA: dDA: cumulative dDA of approximately 1:10:100. Overall, this study confirms that MS functions as a major vector for toxin flux to depth, that Pseudo-nitzschia-derived aggregates should be considered ‘toxic snow’ for MS-associated organisms, and that effects of MS toxicity on interactions with aggregate-associated microbes and zooplankton consumers warrant further consideration.     

Design,synthesis, and docking studies of phenylpicolinamide derivatives bearing 1H-pyrrolo[2,3-b]pyridine moiety as c-Met inhibitors

Four series of phenylpicolinamide derivatives bearing 1H-pyrrolo[2,3-b]pyridine moiety (12a–e, 13a–f, 14a–f and 15a–i) were designed, synthesized and evaluated for the IC₅₀ values against three cancer cell lines (A549, PC-3 and MCF-7) and c-Met kinase. Five selected compounds (13b, 15b, 15d, 15e and 15f) were further evaluated for the activity against HepG2 and Hela cell lines. Eighteen of the compounds showed excellent cytotoxicity activity and selectivity with the IC₅₀ valuables in single-digit μM to nanomole range. Seven of them are equal to more active than positive control Foretinib against one or more cell lines. The most promising compound 15f showed superior activity to Foretinib, with the IC₅₀ values of 1.04 ± 0.11 μM, 0.02 ± 0.01 μM and 9.11 ± 0.55 μM against A549, PC-3 and MCF-7 cell lines, which were 0.62 to 19.5 times more active than Foretinib (IC₅₀ values: 0.64 ± 0.26 μM, 0.39 ± 0.11 μM, 9.47 ± 0.22 μM), respectively. Structure–activity relationships (SARs) and docking studies indicated that replacement of quinoline nucleus of the previous active compounds with 1H-pyrrolo[2,3-b]pyridine moiety maintained even improved the potent cytotoxic activity. The results suggested that the introduction of fluoro atoms to the aminophenoxy part of target compounds or the phenyl group of pyrimidine substituted on C-4 position was benefit for the activity.     

A novel disintegrin protein from Naja naja venom induces cytotoxicity and apoptosis in human cancer cell lines in vitro

Animal venoms and toxins are potential bioresources that have been known to mankind as a therapeutic tool for more than a century through folk and traditional medicine. The purified “disintegrin protein” (64 kDa) from the venom of the Indian cobra snake (Naja naja) exhibited cytotoxic effects of various types of human cancer cell lines such as breast cancer (MCF-7), lung cancer (A549) and liver cancer (HepG2). In vitro cytotoxicity, DNA fragmentation, an apoptotic assay and a cell cycle analysis were performed to evaluate the anticancer activity of disintegrin against the above cell lines. The IC₅₀ value of disintegrin was determined to be 2.5 ± 0.5 μg/mL, 3.5 ± 0.5 μg/mL, and 3 ± 0.5 μg/mL for the MCF-7, A549 and HepG2 cell lines respectively. Moreover, the increased distribution of G0/G1 and S phase led to decreased populations of cells in the G2/M phase of MCF-7, HepG2 and A549 cells.     

Picrasin K,a new quassinoid from Quassia amara L. (Simaroubaceae)

A new quassinoid Picrasin K 1 was isolated from a decoction made of Quassia amara leaves, traditionally used in French Guyana to treat malaria. The structure and relative stereochemistry of 1 was determined through extensive NMR analysis. Picrasin K showed a low activity against Plasmodium falciparum in vitro (IC₅₀ = 8 μM), and a similar low activity on human cancerous cells line (IC₅₀ = 7 μM on MCF-7 cells line).     

Imbalance between matrix metalloproteinases and tissue inhibitor of metalloproteinases in hypertensive vascular remodeling

Structural vascular changes in two-kidney, one-clip (2K-1C) hypertension may result from increased matrix metalloproteinase (MMP)-2 activity. MMP-2 activation is regulated by other MMPs, including transmembrane-MMPs, and by tissue inhibitors of MMPs (TIMPs). We have investigated the localization of MMP-2, -9, -14, and TIMPs 1–4 in hypertensive aortas and measured their levels by zymography/Western blotting and immunohistochemistry. Gelatinolytic activity was assayed in tissues by in situ zymography. Sham-operated and 2K-1C hypertensive rats were treated with doxycycline (or vehicle) for 8 weeks, and the systolic blood pressure was monitored weekly. Doxycycline attenuated 2K-1C hypertension (165 ± 11.7 mmHg versus 213 ± 7.9 mm Hg in hypertensive controls, P < 0.01), and completely prevented increase in the thicknesses of the media and the intima in 2K-1C animals (P < 0.01). Increased amounts of MMP-2, -9, and -14 were found in hypertensive aortas, as well as enhanced gelatinolytic activity. A gradient in the localization of MMP-2, -9, and -14 was found, with increased amounts detected in the intima, at sites with higher gelatinolytic activity. Doxycycline attenuated hypertension induced increases in all the 3 investigated MMPs in both the media and the intima (all P < 0.05), but it did not change the amounts of TIMPs 1–4 (P > 0.05). Therefore, an imbalance between increased amounts of MMPs at the tissue level without a corresponding increase in the quantities of TIMPs, particularly in the intima and inner media layers, appears to account for the increased proteolytic activity found in 2K-1C hypertension-induced maladaptive vascular remodeling.     

Synthesis,and docking studies of phenylpyrimidine-carboxamide derivatives bearing 1H-pyrrolo[2,3-b]pyridine moiety as c-Met inhibitors

Four series of phenylpyrimidine-carboxamide derivatives bearing 1H-pyrrolo[2,3-b]pyridine moiety (14a–e, 15a–g, 16a–e and 17a–g) were designed, synthesized and evaluated for the IC₅₀ values against three cancer cell lines (A549, PC-3 and MCF-7). Four selected compounds (15e, 16a–b and 17a) were further evaluated for the activity against c-Met kinase, HepG2 and Hela cell lines. Most of the compounds showed excellent cytotoxicity activity and selectivity with the IC₅₀ valuables in single-digit μM to nanomole range. Eleven of them are equal to more active than positive control Foretinib against one or more cell lines. The most promising compound 15e showed superior activity to Foretinib against A549, PC-3 and MCF-7 cell lines, with the IC₅₀ values of 0.14 ± 0.08 μM, 0.24 ± 0.07 μM and 0.02 ± 0.01 μM, which were 4.6, 1.6 and 473.5 times more active than Foretinib (0.64 ± 0.26 μM, 0.39 ± 0.11 μM, 9.47 ± 0.22 μM), respectively. Structure–activity relationships (SARs) and docking studies indicated that the replacement of phenylpicolinamide scaffold with phenylpyrimidine fragment of the target compounds was benefit for the activity. What’s more, the introduction of fluoro atom to the aminophenoxy part played no significant impact on the activity and any substituent group on aryl group is unfavourable for the activity.     

Lethal effects of ichthyotoxic raphidophytes,Chattonella marina,C. antiqua,and Heterosigma akashiwo,on post-embryonic stages of the Japanese pearl oyster,Pinctada fucata martensii

The inimical effects of the ichthyotoxic harmful algal bloom (HAB)-forming raphidophytes Heterosigma akashiwo, Chattonella marina, and Chattonella antiqua on the early-life stages of the Japanese pearl oyster Pinctada fucata martensii were studied. Fertilized eggs and developing embryos were not affected following exposure to the harmful raphidophytes; however, all three algal species severely affected trochophores and D-larvae, early-stage D-larvae, and late-stage pre-settling larvae. Exposure to C. marina (5 × 10² cells ml⁻¹), C. antiqua (10³ cells ml⁻¹), and H. akashiwo (5 × 10³ cells ml⁻¹) resulted in decreased success of metamorphosis to the trochophore stage. A complete inhibition of trochophore metamorphosis was observed following exposure to C. antiqua at 5 × 10³ cells ml⁻¹ and C. marina at 8 × 10³ cells ml⁻¹. In all experiments, more than 80% of newly formed trochophores were anomalous, and in the case of exposure to H. akashiwo at 10⁵ cells ml⁻¹ more than 70% of D-larvae were anomalous. The activity rates of D-larvae (1-day-old) were significantly reduced following exposure to C. antiqua (8 × 10³ cells ml⁻¹, 24 h), C. marina (8 × 10³ cells ml⁻¹, 24 h), and H. akashiwo (10⁴ cells ml⁻¹, 24 h). The activity rates of pre-settling larvae (21-day-old) were also significantly reduced following exposure to C. antiqua (10³ cells ml⁻¹, 24 h), C. marina (8 × 10³ cells ml⁻¹, 24 h), and H. akashiwo (5 × 10⁴ cells ml⁻¹, 24 h). Significant mortalities of both larval stages were induced by all three raphidophytes, with higher mortality rates registered for pre-settling larvae than D-larvae, especially following exposure to C. marina (5 × 10²–8 × 10³ cells ml⁻¹, 48–86 h) and C. antiqua (10³–8 × 10³ cells ml⁻¹, 72–86 h). Contact between raphidophyte cells and newly metamorphosed trochophores and D-larvae, 1-day-old D-larvae, and 21-day-old larvae resulted in microscopic changes in the raphidophytes, and then, in the motile early-life stages of pearl oysters. Upon contact and physical disturbance of their cells by larval cilia, H. akashiwo, C. marina and C. antiqua became immotile and shed their glycocalyx. The trochophores and larvae were observed trapped in a conglomerate of glycocalyx and mucus, most probably a mixture of larval mucous and raphidophyte tricosyts and mucocytes. All motile stages of pearl oyster larvae showed a typical escape behavior translating into increased swimming in an effort to release themselves from the sticky mucous traps. The larvae subsequently became exhausted, entrapped in more heavy mucous, lost their larval cilia, sank, become immotile, and died. Although other toxic mediators could have been involved, the results of the present study indicate that all three raphidophytes were harmful only for motile stages of pearl oysters, and that the physical disturbance of their cells upon contact with the ciliary structures of pearl oyster larvae initiated the harmful mechanism. The present study is the first report of lethal effects of harmful Chattonella spp. towards larvae of a bivalve mollusc. Blooms of H. akashiwo, C. antiqua and C. marina occur in all major cultivation areas of P. fucata martensii during the developmental period of their larvae. Therefore, exposure of the motile early-life stages of Japanese pearl oysters could adversely affect their population recruitment. In addition, the present study shows that further research with early-life development of pearl oysters and other bivalves could contribute to improving the understanding of the controversial harmful mechanisms of raphidophytes in marine organisms.     

Synthesis,biological evaluation of novel 4,5-dihydro-2H-pyrazole 2-hydroxyphenyl derivatives as BRAF inhibitors

A series of novel 4,5-dihydropyrazole derivatives (3a–3t) containing hydroxyphenyl moiety as potential V600E mutant BRAF kinase (BRAF^V600E) inhibitors were designed and synthesized. Docking simulation was performed to insert compounds 3d (1-(5-(5-chloro-2-hydroxyphenyl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-yl)ethanone) and 3m (1-(3-(4-chlorophenyl)-5-(3,5-dibromo-2-hydroxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)ethanone) into the crystal structure of BRAF^V600E to determine the probable binding model, respectively. Based on the preliminary results, compound 3d and 3m with potent inhibitory activity in tumor growth may be a potential anticancer agent. Results of the bioassays against BRAF^V600E, MCF-7 human breast cancer cell line and WM266.4 human melanoma cell line all showed several compounds had potent activities IC₅₀ value in low micromolar range, among them, compound 3d and compound 3m showed strong potent anticancer activity, which were proved by that 3d: IC₅₀ = 1.31 μM for MCF-7 and IC₅₀ = 0.45 μM for WM266.5, IC₅₀ = 0.22 μM for BRAF^V600E, 3m: IC₅₀ = 0.97 μM for MCF-7 and IC₅₀ = 0.72 μM for WM266.5, IC₅₀ = 0.46 μM for BRAF^V600E, which were comparable with the positive control Erlotinib.