Anti-plasmodial and antioxidant activities of constituents of the seed shells of Symphonia globulifera Linn f

A xanthone derivative, named gaboxanthone (1), has been isolated from the seed shells of Symphonia globulifera, together with known compounds, symphonin (2), globuliferin (3), guttiferone A (4), sistosterol, oleanolic acid and methyl citrate. The structure of the compound was assigned as 5,10-dihydroxy-8,9-dimethoxy-2,2-dimethyl-12-(3-methylbut-2-enyl) pyrano [3,2-b]xanthen-6(2H)-one, by means of spectroscopic analysis. The anti-plasmodial and antioxidant activities of the phenolic compounds were evaluated, respectively, in culture against W2 strain of Plasmodium falciparum and using the free radical scavenging activity of the DPPH radical, respectively. Compounds 1-4 were found to be active against the Plasmodium parasites (IC(50) of 3.53, 1.29, 3.86 and 3.17 microM, respectively). Guttiferone A (4) showed a potent free radical scavenging activity compared to the well-known antioxidant caffeic acid.     

Synthesis and antiviral properties of some polyphenols related to Salvia genus

An efficient synthesis of the acid part of salvianolic acid E 2 is described. Compound 2 was obtained from vanillin in 10 steps and 21% overall yield. During the synthesis of 2 an unexpected 5-oxo-4b,9b-dihydroindano[1,2-b]benzofuran rac-12 was isolated. Both compounds together with the acid part of salvianolic acid D were active as HIV-1 integrase inhibitors at the submicromolar level. But they did not inhibit the replication of the virus on MT-4 cells.     

Crystal structure of RimI from Salmonella typhimurium LT2, the GNAT responsible for N(alpha)-acetylation of ribosomal protein S18

The three ribosomal proteins L7, S5, and S18 are included in the rare subset of prokaryotic proteins that are known to be N(alpha)-acetylated. The GCN5-related N-acetyltransferase (GNAT) protein RimI, responsible for the N(alpha)-acetylation of the ribosomal protein S18, was cloned from Salmonella typhimurium LT2 (RimI(ST)), overexpressed, and purified to homogeneity. Steady-state kinetic parameters for RimI(ST) were determined for AcCoA and a peptide substrate consisting of the first six amino acids of the target protein S18. The crystal structure of RimI(ST) was determined in complex with CoA, AcCoA, and a CoA-S-acetyl-ARYFRR bisubstrate inhibitor. The structures are consistent with a direct nucleophilic addition-elimination mechanism with Glu103 and Tyr115 acting as the catalytic base and acid, respectively. The RimI(ST)-bisubstrate complex suggests that several residues change conformation upon interacting with the N terminus of S18, including Glu103, the proposed active site base, facilitating proton exchange and catalysis.     

Global-scale predictions of community and ecosystem properties from simple ecological theory

We show how theoretical developments in macroecology, life-history theory and food-web ecology can be combined to formulate a simple model for predicting the potential biomass, production, size and trophic structure of consumer communities. The strength of our approach is that it uses remote sensing data to predict properties of consumer communities in environments that are challenging and expensive to sample directly. An application of the model to the marine environment on a global scale, using primary production and temperature estimates from satellite remote sensing as inputs, suggests that the global biomass of marine animals more than 10(-5) g wet weight is 2.62 x 10(9)t (=8.16 gm(-2) ocean) and production is 1.00 x 10(10) tyr-1 (31.15 gm(-2)yr(-1)). Based on the life-history theory, we propose and apply an approximation for distinguishing the relative contributions of different animal groups. Fish biomass and production, for example, are estimated as 8.99 x 10(8)t (2.80 gm(-2)) and 7.91 x 108 t yr(-1) (2.46 gm(2)yr(-1)respectively, and 50% of fish biomass is shown to occur in 17% of the total ocean area (8.22 gm(-2)). The analyses show that emerging ecological theory can be synthesized to set baselines for assessing human and climate impacts on global scales.     

Synthesis, checkpoint kinase 1 inhibitory properties and in vitro antiproliferative activities of new pyrrolocarbazoles

In the course of structure-activity relationship studies on granulatimide analogues, new pyrrolo[3,4-c]carbazoles have been synthesized in which the imidazole heterocycle was replaced by a five-membered ring lactam system or a dimethylcyclopentanedione. Moreover, the synthesis of an original structure in which a sugar moiety is attached to the indole nitrogen and to a six-membered D ring via an oxygen is reported. The inhibitory activities of the newly synthesized compounds toward checkpoint kinase 1 and their in vitro antiproliferative activities toward three tumor cell lines: murine leukemia L1210, and human colon carcinoma HT29 and HCT116 are described.     

Nestling begging intensity and parental effort in relation to prelaying carotenoid availability

Carotenoids are antioxidants playing major roles in physiologicalfunctions at various stages of an animal's life. Female birdsdeposit large amounts of carotenoids into their eggs. Carotenoidsare, however, a limiting resource, and females are expectedto balance carotenoid deposition into the eggs with their utilizationfor themselves. Carotenoid availability is thus likely to determineboth the levels of yolk carotenoids and maternal care duringrearing. Carotenoids have been shown to benefit the embryo andthe growing nestling, and it can be hypothesized that an increasein carotenoid availability during laying leads to higher nestlingcondition and competitive ability. We manipulated carotenoidavailability to great tit pairs prior to and during egg layingand later partially cross-fostered chicks at hatching. Duringthe rearing period, we measured how carotenoid availabilityaffected nestlings begging behavior and male and female feedingeffort. We also manipulated the ectoparasite load, predictingthat carotenoid supplementation would help adults and nestlingto cope with parasites. Nestlings hatched from eggs laid bycarotenoid-supplemented females and raised in small broods beggedmore intensely. Nestlings in small deparasitized broods alsobegged more actively. The feeding effort of control femalesincreased with brood size, whereas the feeding effort of carotenoid-supplementedfemales was high whatever the brood size. Male feeding effortwas unaffected by our treatment. Our results support the hypothesisthat maternally derived carotenoids increase nestling beggingbehavior and hence competitive ability. They further suggestthat carotenoid availability determines the level of parentalinvestment and can mediate trade-offs between life-history traits.     

Microtubules have opposite orientation in axons and dendrites of Drosophila neurons

In vertebrate neurons, axons have a uniform arrangement of microtubules with plus ends distal to the cell body (plus-end-out), and dendrites have equal numbers of plus- and minus-end-out microtubules. To determine whether microtubule orientation is a conserved feature of axons and dendrites, we analyzed microtubule orientation in invertebrate neurons. Using microtubule plus end dynamics, we mapped microtubule orientation in Drosophila sensory neurons, interneurons, and motor neurons. As expected, all axonal microtubules have plus-end-out orientation. However, in proximal dendrites of all classes of neuron, approximately 90% of dendritic microtubules were oriented with minus ends distal to the cell body. This result suggests that minus-end-out, rather than mixed orientation, microtubules are the signature of the dendritic microtubule cytoskeleton. Surprisingly, our map of microtubule orientation predicts that there are no tracks for direct cargo transport between the cell body and dendrites in unipolar neurons. We confirm this prediction, and validate the completeness of our map, by imaging endosome movements in motor neurons. As predicted by our map, endosomes travel smoothly between the cell body and axon, but they cannot move directly between the cell body and dendrites.     

Relevance of a perchloric acid extraction scheme to determine mineral and organic phosphorus in swine slurry

To increase the phosphorus recycling potential from swine slurry, mineral phosphorus products which could be used as fertilizers should be obtained and new processes need to be investigated. A routine method is needed to better evaluate the dissolved and solid mineral phosphorus in swine slurry. Cold perchloric acid extraction method previously developed for wastewater or sludge analysis was adapted. Ionic chromatography was used to measure orthophosphate in extracts. Only one extraction step was needed to distinguish between mineral and organic phosphorus in slurry. Reproducibility of the method was high (less than 5% of variation on the measured fractions). Selectivity was assessed by adding several organic and mineral phosphorus sources in the slurry. Cold perchloric extraction followed by ionic chromatography was very selective in quantifying both the mineral and organic forms of phosphorus in swine slurry.     

Benzyladenine Promotes Flowering in <Emphasis Type="Italic">Doritaenopsis</Emphasis> and <Emphasis Type="Italic">Phalaenopsis</Emphasis> Orchids

Two experiments were performed to determine how application of the cytokinin benzyladenine (BA) influenced flowering in Doritaenopsis and Phalaenopsis orchid clones. In the first experiment, two vegetative orchid clones growing in 15-cm pots were transferred from a 28°C greenhouse that inhibited flowering to a 23°C greenhouse for flower induction (day 0). A foliar spray (0.2 L m⁻²) containing BA at 100, 200, or 400 mg L⁻¹ or 25, 50, or 100 mg L⁻¹ each of BA and gibberellins A₄ + A₇ (BA+GA) was applied on days 0, 7, and 14. Plants treated with BA alone at 200 or 400 mg L⁻¹ had a visible inflorescence 3–9 days earlier and had a mean of 0.7–3.5 more inflorescences and 3–8 more flowers per plant than nontreated plants. The application of BA+GA had no effect on inflorescence number and total flower number at the rates tested. In the second experiment, three orchid clones received a single foliar spray of BA at 200 mg L⁻¹ at six time points relative to time of transfer from 29°C to 23°C (−1, 0, +1, +2, +4, or +6 weeks). A separate group of plants received a BA application at week 0 but was maintained at 29°C. Inflorescence number was greatest in all three orchid clones when plants were treated with BA 1 week after the temperature transfer. Plants that were sprayed with BA and maintained at 29°C did not initiate inflorescences. The promotion of flowering by the application of BA suggests that cytokinins at least partially regulate inflorescence initiation of Doritaenopsis and Phalaenopsis, but its promotion is conditional and BA application cannot completely substitute for an inductive low temperature.