Trihydroxylated linear diterpenes from the brown alga Bifurcaria bifurcata

Two novel polar diterpenes were isolated from the brown alga Bifurcaria bifurcata collected off the Atlantic coast of Morocco, and their structures established by spectral methods. Both compounds are trihydroxylated acyclic diterpenes derived from 12-hydroxygeranylgeraniol. They were tested in vitro for their cytotoxicity and proved to be active against the NSCLC-N6 cell line. Their absolute configuration at the C-12 position has been determined with a modified Mosher's method [J. Am. Chem. Soc. 113 (1991) 4092] and that of the 12-hydroxygeranylgeraniol (bifurcadiol) has been revised.     

Characterization of the P5 subfamily of P-type transport ATPases in mice

In mammals, the most poorly understood P-type ATPases are those of the P(5) subfamily. To begin characterization of the mammalian P(5)-ATPases, BLAST searches of DNA sequence databases were performed. Five genes were identified in the mouse, human, dog, and rat genomes, and the coding sequences of the mouse genes, termed Atp13a1-Atp13a5, were determined. The intron/exon organization of Atp13a1 differs entirely from those of Atp13a2-5, which are closely related. Amino acid sequence comparisons between the five mouse and two yeast P(5)-ATPases suggest that Atp13a1 is orthologous to the yeast Cod1 gene and that Atp13a2-5 are orthologous to yeast Yor291w. Northern blot analysis showed that Atp13a1, Atp13a2, and Atp13a3 mRNAs were expressed in all mouse tissues, whereas Atp13a4 and Atp13a5 mRNAs were restricted to brain and stomach. While the substrate specificity of these transporters is unknown, their importance is underscored by the presence of homologs in fish, insects, worms, and other eukaryotes.     

Antileishmanial and antifungal acridone derivatives from the roots of Thamnosma rhodesica

Eight furanocoumarins, one coumarin and four acridone derivatives have been identified in the roots of Thamnosma rhodesica (Rutaceae). Rhodesiacridone, one of these acridone derivatives, is reported here for the first time. Its structure was elucidated by spectrometric methods including ESI-HR, EI, DCI mass spectrometry, 1H, 13C and 2D NMR experiments. This novel compound showed activities against the intracellular form of a human pathogen, the protozoan parasite Leishmania major. Two known acridone related compounds, gravacridonediol and 1-hydroxy-10-methylacridone, exhibited activities against the intracellular form of the same parasite and the fungus Cladosporium cucumerinum, respectively.     

Conserved regulation of the Caenorhabditis elegans labial/Hox1 gene ceh-13

Caenorhabditis elegans contains a set of six cluster-type homeobox (Hox) genes that are required during larval development. Some of them, but unlike in flies not all of them, are also required during embryogenesis. It has been suggested that the control of the embryonic expression of the worm Hox genes might differ from that of other species by being regulated in a lineal rather than a regional mode. Here, we present a trans-species analysis of the cis-regulatory region of ceh-13, the worm ortholog of the Drosophila labial and the vertebrate Hox1 genes, and find that the molecular mechanisms that regulate its expression may be similar to what has been found in species that follow a regulative, non-cell-autonomous mode of development. We have identified two enhancer fragments that are involved in different aspects of the embryonic ceh-13 expression pattern. We show that important features of comma-stage expression depend on an autoregulatory input that requires ceh-13 and ceh-20 functions. Our data show that the molecular nature of Hox1 class gene autoregulation has been conserved between worms, flies, and vertebrates. The second regulatory sequence is sufficient to drive correct early embryonic expression of ceh-13. Interestingly, this enhancer fragment acts as a response element of the Wnt/WG signaling pathway in Drosophila embryos.     

Synaptic neurotransmission protein UNC-13 affects RNA interference in neurons

Caenorhabditis elegans UNC-13 is an integral component of the synaptic vesicle cycle, functioning in the priming step. A recent yeast two-hybrid screen against UNC-13 identified three interacting proteins that are thought to function in pathways other than neurotransmitter release. One such protein, ERI-1, negatively regulates exogenous RNA interference in the nervous system and other tissues. This study investigates a role for UNC-13 in RNAi through analysis of RNAi penetrance in unc-13 and eri-1 mutant strains. Feeding these strains double stranded RNA corresponding to a neuronally expressed GFP reporter resulted in a significant reduction of GFP in double mutants compared to GFP expression in eri-1 mutants, indicating that UNC-13 functions in conjunction with ERI-1 in RNAi. There is no evidence for altered neurotransmission in eri-1 mutants.     

Biotransformations of ent-18-acetoxy-6-ketomanoyl oxides epimers at C-13 with filamentous fungi

Two ent-18-acetoxy-6-oxomanoyl oxides, epimers at C-13, have been prepared from ent-6alpha,8alpha,18-trihydroxylabda-13(16),14-diene (andalusol), isolated from Sideritis foetens, by means of several chemical pathways and a regioselective acylation with Candida cylindracea lipase (CCL). Biotransformation of these 13-epimeric ent-manoyl oxides by Fusarium moniliforme and Neurospora crassa produced mainly ent-1beta- or ent-11alpha-hydroxylations, as well as their deacetylated derivatives, in both epimers. In addition, with the 13-epi substrate N. crassa originated other minor hydroxylations by the ent-alpha face at C-1 or at C-12, whereas an ent-11beta-hydroxyl group, probably originated by reduction of an 11-oxo derivative also isolated, was achieved with the 13-normal substrate.     

Characterisation of alkaloids from some Australian Stephania (Menispermaceae) species

Chemical investigations of some Stephania species native to Australia and reportedly employed by Aboriginal people as therapeutic agents, are described. The alkaloids from the forest vines Stephania bancroftii F.M. Bailey and S. aculeata F.M. Bailey (Menispermaceae) have been isolated and characterised. The major alkaloids in the tuber of the former species are (-)-tetrahydropalmatine and (-)-stephanine, whereas these are minor components in the leaves, from which a C-7 hydroxylated aporphine has been identified. The major tuber alkaloids in S. aculeata are (+)-laudanidine, and the morphinoid, (-)-amurine, whose absolute stereochemistry has been established by X-ray structural analysis of the methiodide derivative. No significant levels of alkaloids were detected in S. japonica. Complete and unambiguous 1H and 13C NMR data are presented for these alkaloids.     

Oxygenated diterpenes and other constituents from Moroccan Juniperus phoenicea and Juniperus thurifera var. africana

Six new diterpenic acids isolated as their methyl ester derivatives, i.e., methyl 12-oxo-8alpha,15-dihydroxyabiet-13-en-19-oate, methyl 12-oxo-8alpha-hydroxyabiet-13-en-19-oate, methyl 15-hydroperoxy-8alpha,12alpha-epidioxiabiet-13-en-19-oate, methyl 15-hydroxy-8alpha,12alpha-epidioxiabiet-13-en-19-oate, methyl 15-hydroperoxy-8alpha,14alpha,12alpha,13alpha-diepoxiabietan-13-en-19-oate, and methyl 7alpha,12beta-dihydroxysandaracopimarate, together with two new isovalerate derivatives of p-methoxycinnamyl alcohol and linalool, were isolated from the leaves of Juniperus thurifera var. africana and Juniperus phoenicea, grown in Morocco. The structures of these compounds were established by using spectroscopic techniques, including 2D NMR spectra. The cytotoxicity of the abietane diterpenoids was tested against five cell lines.     

Synthesis and glycosidase inhibitory activity of 1-amino-3,6-anhydro-1-deoxy-d-sorbitol derivatives

3,6-Anhydro-1-(aryl or alkylamino)-1-deoxy-d-sorbitol derivatives have been prepared in four steps from isosorbide, a by-product from the starch industry. The inhibitory activities of these new compounds have been evaluated towards 13 glycosidases. A first lead-compound was identified, which inhibited β-N-acetylglucosaminidase from bovine kidney (82% inhibition at 1 mM).     

Evaluation of the role of sigma B in Mycobacterium smegmatis

The alternate sigma factor, sigB, is known to play a crucial role in maintaining the stationary phase in mycobacteria. In this communication, we have studied the proteomics of Mycobacterium smegmatis mc(2)155 and its two derivatives, one of which has a disrupted sigB gene and the other, PMVSigB, which contains a multicopy plasmid containing sigB. We have identified by two-dimensional gel analyses, several proteins that are over-expressed in PMVSigB compared to mc(2)155. These proteins are either stress proteins or participate actively in different metabolic pathways of the organisms. On the other hand, when sigB deleted mycobacteria were grown until the stationary phase and its two-dimensional protein profile was compared to that of mc(2)155, few DNA binding proteins were found to be up-regulated. We have shown recently that upon over-expressing sigB, the cell surface glycopeptidolipids of M. smegmatis are hyperglycosylated, a situation similar to what was observed for nutritionally starved bacteria. Gene expression profile through quantitative PCR presented here identified a Rhamnosyltransferase responsible for this hyperglycosylation.     

Studies on structure-activity relationship of sphaeropsidins A-F, phytotoxins produced by Sphaeropsis sapinea f. sp. cupressi

Six forms of sphaeropsidins (SA-SF), three- and tetra-cyclic unrearranged pimarane diterpenes produced by Sphaeropsis sapinea f. sp. cupressi, as well as eight derivatives obtained by chemical modification of SA-SC, were assayed for their bioactivity. The effect of each compound on plants which are host or non-host of the pathogen was investigated. Activity on some plant pathogenic fungi was also tested. Some structure-activity relationships have been identified for both phytotoxic and antifungal activity. It appears that the integrity of the tricyclic pimarane system, the preservation of the double bond C(8)-C(14), the tertiary hydroxyl group at C-9, the vinyl group at C-13, and the carboxylic group at C-10 as well as the integrity of the A-ring provide these molecules with non selective phytotoxic and antimycotic activity.     

Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata

The crude methanol extract of the seeds of Derris trifoliata showed potent and dose dependent larvicidal activity against the 2nd instar larvae of Aedes aegypti. From this extract two unusual rotenoid derivatives, a rotenoloid (named 7a-O-methyl-12a-hydroxydeguelol) and a spirohomooxarotenoid (named spiro-13-homo-13-oxaelliptone), were isolated and characterised. In addition a rare natural chromanone (6,7-dimethoxy-4-chromanone) and the known rotenoids rotenone, tephrosin and dehydrodeguelin were identified. The structures were assigned on the basis of spectroscopic evidence. The larvicidal activity of the crude extract is mainly due to rotenone.     

Hygrophorones A-G: fungicidal cyclopentenones from Hygrophorus species (Basidiomycetes)

Twenty new 5-(hydroxyalkyl)-2-cyclopentenone derivatives (hygrophorones) could be isolated from Hygrophorus latitabundus, H. olivaceoalbus, H. persoonii, and H. pustulatus. Their fungicidal activity was exemplarily tested. The hygrophorones have structural similarities to the antibiotic pentenomycin. Chemically, hygrophorones are 2-cyclopentenones with hydroxy or acetoxy substituents at C-4 and/or C-5. An odd-numbered 1' oxidized alkyl chain (C(11), C(13), C(15), or C(17)) is attached at C-5. In addition, from H. persoonii the new gamma-butyrolactone derivative [5-(E)-2-hydroxytetradexylidene-5H-furan-2-one] could be isolated. Some hygrophorones are responsible for the color reaction of the stipes of these fungi upon treatment with potassium hydroxide solution. Structural elucidations are based on 1D ((1)H, (13)C) and 2D (COSY, NOESY, HSQC, HMBC) NMR spectroscopic analyses as well as HR-FT-ICR-MS investigations.     

Whole genome re-sequencing identifies a mutation in an ABC transporter (mdr2) in a Plasmodium chabaudi clone with altered susceptibility to antifolate drugs

In malaria parasites, mutations in two genes of folate biosynthesis encoding dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) modify responses to antifolate therapies which target these enzymes. However, the involvement of other genes which modify the availability of exogenous folate, for example, has been proposed. Here, we used short-read whole-genome re-sequencing to determine the mutations in a clone of the rodent malaria parasite, Plasmodium chabaudi, which has altered susceptibility to both sulphadoxine and pyrimethamine. This clone bears a previously identified S106N mutation in dhfr and no mutation in dhps. Instead, three additional point mutations in genes on chromosomes 2, 13 and 14 were identified. The mutated gene on chromosome 13 (mdr2 K392Q) encodes an ABC transporter. Because Quantitative Trait Locus analysis previously indicated an association of genetic markers on chromosome 13 with responses to individual and combined antifolates, MDR2 is proposed to modulate antifolate responses, possibly mediated by the transport of folate intermediates.     

Association of interleukin-13 SNP rs1800925 with allergic rhinitis risk: A meta-analysis based on 1,411 cases and 3169 controls

Studies investigating the association between interleukin-13 (IL-13) single nucleotide polymorphism (SNP) rs1800925 and allergic rhinitis risk have reported conflicting results. The aim of the present study was to conduct a meta-analysis assessing the possible association of IL-13 SNP rs1800925 with allergic rhinitis risk. The relevant studies were identified through a search of PubMed, Embase, ISI Web of Knowledge and Chinese National Knowledge Infrastructure until December 2011 and selected on the basis of the established inclusion criteria for publications. Five studies were included in the present meta-analysis (1411 cases and 3169 controls). The combined results based on all studies showed that IL-13 SNP rs1800925 was not associated with increased allergic rhinitis risk (T versus C: odds ratio (OR)=1.06, 95% confidence interval (CI)=0.94-1.20; C/T versus C/C: OR=1.12, 95% CI=0.97-1.29; T/T versus C/C: OR=1.00, 95% CI=0.69-1.44; C/T+T/T versus CC: OR=1.10, 95% CI=0.96-1.27; T/T versus C/C+C/T: OR=0.91, 95% CI=0.64-1.31). This meta-analysis supported that IL-13 SNP rs1800925 was not associated with allergic rhinitis.     

Lipodystrophies: Disorders of adipose tissue biology

The adipocytes synthesize and store triglycerides as lipid droplets surrounded by various proteins and phospholipids at its surface. Recently, the molecular basis of some of the genetic syndromes of lipodystrophies has been elucidated and some of these genetic loci have been found to contribute to lipid droplet formation in adipocytes. The two main types of genetic lipodystrophies are congenital generalized lipodystrophy (CGL) and familial partial lipodystrophy (FPL). So far, three CGL loci: 1-acylglycerol-3-phosphate-O-acyltransferase 2 (AGPAT2), Berardinelli–Seip Congenital Lipodystrophy 2 (BSCL2) and caveolin 1 (CAV1) and four FPL loci: lamin A/C (LMNA), peroxisome proliferator-activated receptor γ (PPARG), v-AKT murine thymoma oncogene homolog 2 (AKT2) and zinc metalloprotease (ZMPSTE24), have been identified. AGPAT2 plays a critical role in the synthesis of glycerophospholipids and triglycerides required for lipid droplet formation. Another protein, seipin (encoded by BSCL2 gene), has been found to induce lipid droplet fusion. CAV1 is an integral component of caveolae and might contribute towards lipid droplet formation. PPARγ and AKT2 play important role in adipogenesis and lipid synthesis. In this review, we discuss and speculate about the contribution of various lipodystrophy genes and their products in the lipid droplet formation.     

Synthetic studies on glycosphingolipids from Protostomia phyla: total syntheses of glycosphingolipids from the parasite, Echinococcus multilocularis

Efficient and systematic syntheses of four neutral glycosphingolipids that have been isolated from the metacestodes of Echinococcus multilocularis have been achieved. A key step is the direct glycosylation of galactosyl donors using thioglycosides with benzoyl ceramide in the presence of N-iodosuccinimide (NIS)/TfOH, which gave the desired oligosaccharide derivatives. The fully protected glycosides 13, 20, 22 and 25 were deprotected to give four target glycosphingolipids (1-4).     

Cytotoxic clerodane diterpenes from Glossocarya calcicola

Three clerodane diterpenes were isolated and identified from leaf extract of Glossocarya calcicola. Compound has been characterised as (rel)-10betaH-trans-12xi-(2-methylbut-2(E)-enoyl)-1beta-(isobutanoyl)-6alpha,13xi-dihydroxyclerodan-4(20),8(18)-dien-7,15-dione-15,16-oxide, to which we have assigned the trivial name calcicolin-A. The other two compounds had the same skeletal structure and C-12 substituent but in compound, the C-1 esterifying group becomes 2-methylbut-2(E)-enoic acid and in it becomes 2-methylbutanoic acid. Although anti-insect activity was not observed for G. calcicola, cytotoxicity against insect and human carcinoma cell lines was detected.     

Synthesis and receptor-binding examinations of the normal and 13-epi-D-homoestrones and their 3-methyl ethers

An effective epimerization of the normal estrone 3-methyl and 3-benzyl ethers by using o-phenylenediamine and AcOH made the possibility for facile entry into the 13alpha-estrone series. Combination of this synthetic methodology with an isolation step carried out by means of the Girard-P reagent, the corresponding ethers of 13-epi-estrone were obtained in excellent yields. The 3-hydroxy and 3-methoxy D-homoestrone derivatives in both the normal and the 13alpha-estrone series were then synthesized and tested in vitro in a radioligand-binding assay. The estrogen receptor recognizes these compounds, but their relative binding affinities (RBAs) are lower than that of the reference compound 3,17beta-estradiol. The progesterone receptor-binding affinities of the four D-homo derivatives were also tested showing low values for 13alpha-D-homoestrone and its 3-methyl ether. Pharmacologically, these 13alpha-D-homoestrone derivatives are estrogen receptor-selective molecules.