Search

Objectives:Daniellia oliveriRolfe is a well-known plant of Fabaceae family whose previous phytochemical and pharmacological studies led to the identification of triterpenoid, phenol, anthraquinone oxalate with antioxidant, antibacterial and antifungal activities. This study aimed to investigate chemical constituents and evaluate the antimicrobial potency of the root of D. oliveri. Methods:The methanol extract of the root barks of D. oliveriwas subjected to silica gel chromatographic separation. The structures of the isolated compounds (1-9) were determined by analyzing their spectrometric and spectroscopic spectra. Single-crystal-Xray analysis was used to establish the absolute skeletal structure of compound 1. Crude extract, fractions and compounds were investigated against four bacteria vis Pseudomonas aeruginosa27853, Escherichia coli5, Staphylococcus aureus25923 and Streptococcussp.9619 and, two yeast vis Candida albicans14053 and Candida tropicalis018 using broth microdilution method. Results:The phytochemical prospection of the methanol extract of D. oliveriallowed the isolation of a naturally crystallized diterpenoid type furolabdane: polyalthic acid 1, as well as eight amorphous compounds (2-9). Among the tested samples, the crude extract, fractions and compounds selectively showed inhibitory effects against the tested microorganisms with MIC values ranging from 4 to 1024 μg/mL. Fraction D1 and compounds 1, 4, 7, 8and 9exhibited the broadest antimicrobial effects among fractions and compounds while D5 and compound 1showed the best activity with MIC values of 16 and 4 μg/mL respectively against E. coliwhich appeared to be the most sensitive strain.Conclusion:Polyaltic acid (1) showed the best activity with significant MIC value of 4 μg/mL identical to that of ceftazidine against E. coli.The MIC values of the active compounds 1, 4and 7are comparable to those of ceftazidime. Then, these compounds from natural origin, could serve as markers in the standardization of Danielliaplant as phytomedicine.

Entada abyssinicaSteud. Ex A. Rich (Leguminosae) is a medicinal plant used traditionally for the treatment of infections. A phytochemical investigation of the methanol extract of E. abyssinicaroot bark led to the isolation of a new phenanthrene derivative named phenentada (1), together with seven known compounds (8 S, 13 E)-kolavic acid 15-methyl ester (2) and 8 S-kolavic acid 15-methyl ester (3) obtained as mixture, 8 S-kolavic acid 15-methyl ester (3), 8 S-kolavic acid 18-methyl ester (4),13,14,15,16-tetranorclerod-3-ene-12,18-dioic acid (5), 1′,26′-bis-[(S)-2,3-dihydroxypropyl] hexacosanedioate (6), campesterol (7) and 3-O-β-d-glucopyranosylstigmasterol (8). Their structures were determined by NMR spectroscopy (1D and 2D), mass spectrometry (HRESIMS) and by comparison with previously reported data. The crude extract and some isolated compounds were evaluated for their in vitroantimicrobial activities by the microdilution method while, the antioxidant activity was evaluated by the DPPH methods. Regarding the antimicrobial activity, the crude extract showed significant inhibitory activities against bacteria strains (MIC 7.81–31.3 μg mL−1) and yeasts (MIC 15.6–31.3 μg mL−1) whereas all compounds tested exhibited significant activity against Staphylococcus epidermidis.Moreover, compounds 4, 5and 6and the mixture 2/3showed significant antimicrobial activity on Candida parapsilosisstrain (MIC = 3.12 μg mL−1), as well as selected antifungal property against candidapathogenic fungi strains. On the other hand, compounds (1) demonstrated the best bioactivities against Candida albicansand Salmonella entericawith MIC = 3.12 μg mL−1while the mixture 2/3appeared to have the highest inhibition on gram (+) bacteria strain S. epidermidiswith MIC of 0.78 μg mL−1and compound 5 (MIC = 1.56 μg mL−1) against the gram (−) bacteria strain. Furthermore, the SC50values measured by the antioxidant test for all samples varied between 47.21 and 52.44 μg mL−1for DPPH. These results support the traditional uses of E. abyssinicain the management of several diseases including the claim in the skin disease treatment. Additionally, here is reported the first time isolation of a phenanthrene derivative in the Fabaceae family to the best of our knowledge.

Termiglaucescin (1), a new triterpene glucoside, has been isolated from the ethyl acetate extract of the root bark of Terminalia glaucescensPlanch. ex Benth, together with 11 known compounds, β-D-glucopyranosyl 2α,3β,6β-trihydroxy-23-galloylolean-12-en-28-oate (2), arjunglucoside I (3), sericoside (4), arjungenin (5), sericic acid (6), arjunetin (7), chebuloside II (8), 3,3′,4-tri-O-methylelagic acid (9), 3,3′-di-O-methylelagic acid (10), β-sitosterol (11) and stigmasterol (12). Compounds 2, 3, 7, 8and 9are reported from the plant for the first time. The structures of the isolated compounds were characterized by spectroscopic data interpretations, especially 1D and 2D NMR. The triterpenic isolates showed potent antioxidant and anti-inflammatory activities.

Four well-differentiated clusters have been identified among iron-oxidizing acidithiobacilli. One monophyletic group clusters with At. ferrooxidansT and another with strains of At. ferrivorans. While At. ferrooxidans and At. ferrivorans share many physiological traits, they differ in some phenotypic characteristics such as motility, pH and temperature minima, and also in terms of genes involved in ferrous iron oxidation. The genome of a strain (CF27) of At. ferrivorans, which is characterized by its marked propensity to form macroscopic growths and biofilms, was sequenced at Genoscope (Evry, France). Comparative genomic studies were carried with all related Acidithiobacillus strains that have been sequenced to date, in order to identify genetic determinants responsible for physiological traits relating to the oxidation of iron and sulfur, and also to extracellular polymeric substances formation.

On the basis of functional and phylogenetic criteria, we have identified a total of 229 subfamilies and 111 singletons predicted to carry out transport or other membrane functions in Saccharomyces cerevisiae. We have extended the Transporter Classification (TC) and created a Membrane Classification (MC) for non-transporter membrane proteins. Using the preliminary phylogenetic digits X, Y, Z (for new families, subfamilies, and clusters, respectively), we allocated a five-digit number to 850 proteins predicted to contain more than two transmembrane domains. Compared with a previous TC of the yeast genome, we classified an additional set of 538 membrane proteins (transporters and non-transporters) and identified 111 novel phylogenetic subfamilies.

Nicotinamidase (NAMase) from the budding yeast, Saccharomyces cerevisiae, was purified by Ni²⁺ affinity chromatography and gel filtration. N-terminal microsequencing revealed sequence identity with a hypothetical polypeptide encoded by the yeast YGL037C open reading frame sharing 30% sequence identity with Escherichia coli pyrazinamidase/nicotinamidase. A yeast strain in which the NAMase gene, hereafter named PNC1, was deleted shows a decreased intracellular NAD⁺ concentration, consistent with the loss of NAMase activity in the null mutant. In wild-type strains, NAMase activity is stimulated during the stationary phase of growth, by various hyperosmotic shocks or by ethanol treatment. Using a PPNC1::lacZ gene fusion, we have shown that this stimulation of NAMase activity results from increased levels of the protein and requires stress response elements in the 5' non-coding region of PNC1. These results suggest that NAMase helps yeast cells to adapt to various stress conditions and nutrient depletion, most likely via the activation of NAD-dependent biological processes. Copyright © 2002 John Wiley & Sons, Ltd.

Nicotinamidase (NAMase) from the budding yeast, Saccharomyces cerevisiae, was purified by Ni2+affinity chromatography and gel filtration. N‐terminal microsequencing revealed sequence identity with a hypothetical polypeptide encoded by the yeast YGL037C open reading frame sharing 30% sequence identity with Escherichia colipyrazinamidase/nicotinamidase. A yeast strain in which the NAMase gene, hereafter named PNC1, was deleted shows a decreased intracellular NAD+concentration, consistent with the loss of NAMase activity in the null mutant. In wild‐type strains, NAMase activity is stimulated during the stationary phase of growth, by various hyperosmotic shocks or by ethanol treatment. Using a PPNC1::lacZgene fusion, we have shown that this stimulation of NAMase activity results from increased levels of the protein and requires stress response elements in the 5′ non‐coding region of PNC1. These results suggest that NAMase helps yeast cells to adapt to various stress conditions and nutrient depletion, most likely via the activation of NAD‐dependent biological processes. Copyright © 2002 John Wiley & Sons, Ltd.

Since its completion more than 4 years ago, the sequence of Saccharomyces cerevisiaehas been extensively used and studied. The original sequence has received a few corrections, and the identification of genes has been completed, thanks in particular to transcriptome analyses and to specialized studies on introns, tRNA genes, transposons or multigene families. In order to undertake the extensive comparative sequence analysis of this program, we have entirely revisited the S. cerevisiaesequence using the same criteria for all 16 chromosomes and taking into account publicly available annotations for genes and elements that cannot be predicted. Comparison with the other yeast species of this program indicates the existence of 50 novel genes in segments previously considered as ‘intergenic’ and suggests extensions for 26 of the previously annotated genes.

Since its completion more than 4 years ago, the sequence of Saccharomyces cerevisiaehas been extensively used and studied. The original sequence has received a few corrections, and the identification of genes has been completed, thanks in particular to transcriptome analyses and to specialized studies on introns, tRNA genes, transposons or multigene families. In order to undertake the extensive comparative sequence analysis of this program, we have entirely revisited the S. cerevisiaesequence using the same criteria for all 16 chromosomes and taking into account publicly available annotations for genes and elements that cannot be predicted. Comparison with the other yeast species of this program indicates the existence of 50 novel genes in segments previously considered as ‘intergenic’ and suggests extensions for 26 of the previously annotated genes.

Phytochemical study of the roots of Erythrina senegalensisled to the isolation of a new α-sophoradiol glycoside, erythrinoside (1), together with four known compounds, lupeol (2), α-sophoradiol (3), isoneorautenol (4) and D-mannitol (5). The structures of the compounds were elucidated using spectroscopic data including 1D and 2D NMR, mass spectrometry and by comparison made with some data reported previously; the samples (extracts and compounds) were also subjected to antidiabetic assay. Erythrinoside and isoneorautenol exhibited good α-amylase inhibitory potential of 54.6% and 53.3%, respectively, compared to acarbose (72.5%) at 400 µg/mL. With α-glucosidase, all samples showed promising inhibition percentages above 50% at 200 µg/mL. In the α-glucosidase assay, the ethyl acetate extract (65.5%), methanol extract (72.1%), erythrinoside (63.3%) and isoneorautenol (66.0%) had percentage inhibitions closer to that of acarbose (69.0%) at 200 µg/mL. The methanol extract (IC50= 81.2 ± 0.9 µg/mL) was more active than acarbose (IC50= 94.5 ± 0.7 µg.mL) in the α-glucosidase assay. The inhibition of α-amylase and α-glucosidase indicates that E. senegalensisextracts and compounds could be used to manage diabetic conditions.

The sarco(endo)plasmic reticulum of animal cells contains an ATP-powered Ca2+pump that belongs to the P-type family of membrane-bound cation-translocating enzymes. InSchistosoma mansoni, the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is encoded by the SMA1and SMA2genes. A full-length SMA2cDNA clone was isolated, sequenced, and expressed into a yeast Ca2+-ATPase-deficient strain requiring plasmid-borne rabbit SERCA1a for viability. The S. mansoniCa2+-ATPase supports growth of mutant cells lacking SERCA1a, indicating functional expression in yeast and a role in calcium sequestration. Subcellular fractionation showed that the SMA2 ATPase is localized in yeast internal membranes. SMA2 expression was found to be associated with thapsigargin-sensitive, Ca2+-dependent ATPase activity. The activity increased 2-fold upon calcineurin inactivation, which correlates within vivostimulated contribution of SMA2 in calcium tolerance. These results suggest that calcineurin controls calcium homeostasis by inhibiting Ca2+-ATPase activity in an internal compartment.

Abstract: This study was aimed at isolating hypaphorine from Erythrina mildbraediiHarms (Fabaceae) and Erythrina addisioniaeHutch. & Datziel (Fabaceae) in order to determine its structural and antibacterial effects. Density functional theory (DFT) calculations and X-ray crystallographic analysis of the isolated hypaphorine was determined. The antibacterial effects of hypaphorine against a number of Gram positive and Gram negative bacterial strains were investigated. The root mean square deviation between the experimental and calculated bond lengths and bond angles of hypaphorine were found to be 0.046 Å and 1.5° respectively. The highest occupied molecular orbital (HOMO) of hypaphorine was delocalised on the indole moiety whereas the lowest occupied molecular orbital (LUMO) was delocalised on the –N(CH3)3group and the HOMO–LUMO gap of hypaphorine was 4.65 eV. Hypaphorine inhibited the growth of the Gram-positive bacteria tested, namely Bacillus cereus, B. subtilis, Staphylococcus aureusand S. epidermidis.The lowest minimum inhibitory concentration (MIC) value of 2 mg/mL was exhibited against Mycobacterium smegmatis, Staphylococcus aureusand B. subtilis. The theoretical and experimental results from this study showed that hypaphorine is capable of forming quadrupole moments thus explaining its antibacterial effects on Gram positive bacteria. Graphic abstract:

We have screened the genome of Saccharomyces cerevisiae for fragments that confer a growth-retardation phenotype when overexpressed in a multicopy plasmid with a tetracycline-regulatable (Tet-off) promoter. We selected 714 such fragments with a mean size of 700 base-pairs out of around 84,000 clones tested. These include 493 in-frame open reading frame fragments corresponding to 454 distinct genes (of which 91 are of unknown function), and 162 out-of-frame, antisense and intergenic genomic fragments, representing the largest collection of toxic inserts published so far in yeast.