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Abstract: Two new ent-kauren-19-oic acid derivatives, ent-14S*-hydroxykaur-16-en-19-oic acid and ent-14S*,17-dihydroxykaur-15-en-19-oic acid together with eleven known compounds ent-kaur-16-en-19-oic acid, ent-kaur-16-en-19-al, ent-12β-hydroxykaur-16-en-19-oic acid, ent-12β-acetoxykaur-16-en-19-oic acid, 8R,13R-epoxylabd-14-ene, eudesm-4(15)-ene-1β,6α-diol, (−)-7-epivaleran-4-one, germacra-4(15), 5E,10(14)-trien-9β-ol, acetyl aleuritolic acid, β-amyrin, and stigmasterol were isolated from the stem bark of Croton pseudopulchellus (Euphorbiaceae). Structures were determined using spectroscopic techniques. Ent-14S*-hydroxykaur-16-en-19-oic acid, ent-kaur-16-en-19-oic acid, ent-12β-hydroxykaur-16-en-19-oic acid, ent-12β-acetoxykaur-16-en-19-oic acid and 8R,13R-epoxylabd-14-ene were tested for their effects on Semliki Forest virus replication and for cytotoxicity against human liver tumour cells (Huh-7 strain) but were found to be inactive. Ent-kaur-16-en-19-oic acid, the major constituent, showed weak activity against the Plasmodium falciparum (CQS) D10 strain. [Copyright &y& Elsevier]

Abstract: On the basis of structural features known to be critical for the antimalarial activity, accumulation and uptake of chloroquine (CQ), as well as chemosensitization of CQ resistant Plasmodium falciparum, an exploratory novel series of potential dual acting antiplasmodial and chemosensitizing agents was designed and synthesized for biological evaluation. All four compounds contain a common alkyl side chain with two amino groups and differ only in the chemical nature of the hydrophobic aromatic moieties. Among them, N′-[4-(biphenyl-2-ylmethoxy)-benzyl]-N,N-dimethyl-propane-1,3-diamine (P7) displayed the greatest potential as a dual-acting antiplasmodial agent against CQ-resistant strains and chemosensitizer (RMIK1 =0.67; RMIRSA11 =0.82) while displaying low in vitro cytotoxicity against a mammalian cell line (CHO). At 1μM, P7 caused a 8.5 and 4-fold potentiation in CQ accumulation in resistant P. falciparum K1 and RSA11 strains, respectively. In a parallel experiment, 1μM verapamil showed a 6.5 (K1) and 2 (RSA11)-fold increase in CQ accumulation. The preliminary studies point to structural features that may determine antiplasmodial and/or CQ resistance modulating activity in this new series of compounds. An additive effect was observed against both CQS (D10) and CQR (RSA11) strains when CQ and P7 were used at their corresponding IC50 concentrations in isobologram analysis. [Copyright &y& Elsevier]

The polymorphic enzyme phosphoglucomutase showed a significant genetic change and seasonal excess of homozygotes in two species of anchovy repetitively sampled during the spawning periods over 2 years in the Arabian Gulf. Samples from the peak spawning periods were not in genetic equilibrium, which is unexpected as spawning stocks are thought to show the greatest level of genetic isolation, and indicate that assortative mating may occur. [Copyright &y& Elsevier]

Five techniques were used to determine stock relationships between four spatially isolated but geographically close orange roughy fisheries in the eastern Tasman Sea: the Lord Howe Rise (HOWE), Northwest Challenger (NWCH), Southwest Challenger (SWCH), and Westpac Bank (WPAC). The techniques included life history traits (age and length at maturity), population length frequency analysis, otolith shape analysis, genetic makers, and a comparison of spawning times. The estimated ages and lengths at onset of maturity did not identify clear stock differences between the four areas. Otolith shape revealed two groups: HOWE/NWCH and SWCH/WPAC. There were significant size differences between HOWE and NWCH (and between HOWE–SWCH and HOWE–WPAC) with larger fish on HOWE. One out of six nuclear DNA markers revealed significant heterogeneity among sites. Mitochondrial DNA polymorphisms of the control region revealed no heterogeneity among areas, but restriction digests of the whole mitochondrial genome revealed differences between HOWE and NWCH/SWCH. There was considerable between-year variation in the time of the onset of spawning at SWCH (3 weeks) and WPAC (4 weeks). In both areas, the time of spawning was later in the early 1990s than in the late 1990s. No major oceanographic features that might isolate stocks were identified in this region of the Tasman Sea. The biological differences between orange roughy taken from HOWE, NWCH, and SWCH indicate that these fisheries could be managed as independent stocks. There were no biological differences between SWCH and WPAC and these fisheries probably exploit one straddling stock. [Copyright &y& Elsevier]