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p. 2733-2743
Received: 9 September 2010; in revised form: 14 October 2010 / Accepted: 22 October 2010 / Published: 29 October 2010
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| Download PDF Full-text (329 KB) | Download XML Full-text Abstract: In the present study, we investigated the antileishmanial activity of sesquiterpene elatol, the major constituent of the Brazilian red seaweed Laurencia dendroidea (Hudson) J.V. Lamouroux, against L. amazonensis. Elatol after 72 h of treatment, showed an IC50 of 4.0 µM and 0.45 µM for promastigote and intracellular amastigote forms of L. amazonensis , respectively. By scanning and transmission electron microscopy, parasites treated with elatol revealed notable changes compared with control cells, including: pronounced swelling of the mitochondrion; appearance of concentric membrane structures inside the organelle; destabilization of the plasma membrane; and formation of membrane structures, apparently an extension of the endoplasmic reticulum, which is suggestive of an autophagic process. A cytotoxicity assay showed that the action of the isolated compound is more specific for protozoa, and it is not toxic to macrophages. Our studies indicated that elatol is a potent antiproliferative agent against promastigote and intracellular amastigote forms, and may have important advantages for the development of new anti-leishamanial chemotherapies.
p. 2744-2754
Received: 1 October 2010; in revised form: 22 October 2010 / Accepted: 26 October 2010 / Published: 1 November 2010
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| Download PDF Full-text (216 KB) | Download XML Full-text Abstract: The new secondary metabolites verrucosidinol (1 ) and its derivative verrucosidinol acetate (2 ), together with a potent neurotoxin verrucosidin (3 ), a congener norverrucosidin (4 ) and a mixture of two known phytotoxic metabolites terrestric acids (5 and 6 ), were isolated from the marine derived fungus Penicillium aurantiogriseum . Verrucosidinol has a ring-opened ethylene oxide moiety in the polyene α-pyrone skeleton, and verrucosidinol acetate is its acetate derivative. The chemical structures were determined by comparing with literature data and a combination of spectroscopic techniques, including high resolution mass spectrum and two-dimentional nuclear magnetic resonance spectroscopic analysis.
p. 2755-2780
Received: 17 September 2010; in revised form: 27 October 2010 / Accepted: 4 November 2010 / Published: 5 November 2010
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| Download PDF Full-text (1332 KB) | Download XML Full-text Abstract: Thiazoles, oxazole and their corresponding reduced derivatives, thiazolines and oxazolines, are found in marine sources exhibiting significant biological activities. The isolation, synthetic, and biological studies of these natural products, covering literature from January 2007 to June 2010, are summarized.
p. 2781-2794
Received: 20 September 2010; in revised form: 25 October 2010 / Accepted: 2 November 2010 / Published: 5 November 2010
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| Download PDF Full-text (301 KB) | Download XML Full-text Abstract: Sialyltransferases transfer N -acetylneuraminic acid (Neu5Ac) from the common donor substrate of these enzymes, cytidine 5’-monophospho-N -acetylneuraminic acid (CMP-Neu5Ac), to acceptor substrates. The enzymatic reaction products including sialyl‑glycoproteins, sialyl-glycolipids and sialyl-oligosaccharides are important molecules in various biological and physiological processes, such as cell-cell recognition, cancer metastasis, and virus infection. Thus, sialyltransferases are thought to be important enzymes in the field of glycobiology. To date, many sialyltransferases and the genes encoding them have been obtained from various sources including mammalian, bacterial and viral sources. During the course of our research, we have detected over 20 bacteria that produce sialyltransferases. Many of the bacteria we isolated from marine environments are classified in the genus Photobacterium or the closely related genus Vibrio . The paper reviews the sialyltransferases obtained mainly from marine bacteria.
p. 2795-2809
Received: 26 September 2010; in revised form: 14 October 2010 / Accepted: 2 November 2010 / Published: 8 November 2010
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| Download PDF Full-text (311 KB) | Download XML Full-text Abstract: An organic extract from fresh shrimp (Litopenaeus vannamei ) was studied for antimutagenic and antiproliferative properties using Salmonella typhimurium tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line (B-cell lymphoma), respectively. Shrimp extract was sequentially fractionated by thin layer chromatography (TLC) and each fraction was tested for antimutagenic and antiproliferative activities. Crude organic extracts obtained from shrimp reduced the number of revertants caused by aflatoxina B1 , showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. These results suggested that the lipid fraction of the tested species contained compounds with chemoprotective properties that reduce the mutagenicity of AFB1 and proliferation of a cancer cell line.
p. 2810-2836
Received: 19 September 2010; in revised form: 3 November 2010 / Accepted: 8 November 2010 / Published: 10 November 2010
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| Download PDF Full-text (1705 KB) | Download XML Full-text Abstract: A large variety of unique N- atom containing compounds (alkaloids) without terrestrial counterparts, have been isolated from marine invertebrates, mainly sponges and ascidians. Many of these compounds display interesting biological activities. In this report we present studies on nitrogenous compounds, isolated by our group during the last few years, from Indo-Pacific sponges, one ascidian and one gorgonian. The major part of the review deals with metabolites from the Madagascar sponge Fascaplysinopsis sp., namely, four groups of secondary metabolites, the salarins, tulearins, taumycins and tausalarins.
p. 2837-2848
Received: 1 October 2010; in revised form: 18 October 2010 / Accepted: 4 November 2010 / Published: 10 November 2010
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| Download PDF Full-text (357 KB) | Download XML Full-text | Abstract: Chemical examination of a Chinese soft coral Lobophytum pauciflorum resulted in the isolation of five new biscembranoids named lobophytones O–S (1 –5 ) and a new “monomeric” cembrane lobophytone T (6 ). The structures of the new compounds were elucidated by interpretation of 1D and 2D NMR (COSY, HSQC, HMBC, and NOESY) spectroscopic data in association with MS and IR data. Lobophytone Q showed significant inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) release in mouse peritoneal macrophages, while lobophytones Q and T showed inhibitory activities against the bacteria S . aureus and S . pneumoniae.
Displaying article 1-7
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