Isolation of β-Tocopherol from the Root Bark of the Mulberry Tree

Kluyvera citrophila KY7844 enzymatically catalyzed N-acylation of 7-amino-desacetoxycephalosporanic acid with 1-(1H)-tetrazolylacetate methylester to produce 7-[1-(1H)-tetrazolylacetamido]-desacetoxycephalosporanic acid. The product was purified and characterized.     

Preparation of a glycosynthase from the β-glycosidase of the Archaeon Pyrococcus horikoshii

The β-glycosidase from the hyperthermophilic Archaeon Pyrococcus horikoshii (Phoβ-gly) is a monomeric enzyme with wide substrate specificity belonging to family 1 of glycoside hydrolases classification. Inspection of the three-dimensional structure of the enzyme, recently resolved, showed that Phoβ-gly is membrane bound and that the residues putatively involved in the catalytic activity are Glu155 and Glu324 working as the general acid/base and the nucleophile of the reaction, respectively. We show here that mutation of the latter completely eliminated the activity of the enzyme and that it could be reactivated in the presence of sodium formate. Analysis of the products obtained in the presence of sodium formate buffer pH 4.0 at 75°C showed that the Glu324Gly mutant acts as a hyperthermophilic glycosynthase.     

Evolution of the mammary gland from the innate immune system?

The mammary gland is a skin gland unique to the class Mammalia. Despite a growing molecular and histological understanding of the development and physiology of the mammary gland, its functional and morphological origins have remained speculative. Numerous theories on the origin of the mammary gland and lactation exist. The purpose of the mammary gland is to provide the newborn with copious amounts of milk, a unique body fluid that has a dual role of nutrition and immunological protection. Interestingly, antimicrobial enzymes, such as xanthine oxidoreductase or lysozyme, are directly involved in the evolution of the nutritional aspect of milk. We outline that xanthine oxidoreductase evolved a dual role in the mammary gland and hence provide new evidence supporting the hypothesis that the nutritional function of the milk evolved subsequent to its protective function. Therefore, we postulate that the mammary gland evolved from the innate immune system. In addition, we suggest that lactation partly evolved as an inflammatory response to tissue damage and infection, and discuss the observation that the two signaling pathways, NF-kB and Jak/Stat, play central roles in inflammation as well as in lactation.     

Articulations of Islamophobia: from the extreme to the mainstream?

This article will examine the construction and functions of, as well as relationship between, the diverse and changing articulations of Islamophobia. The aim is to contribute to debates about the definition of Islamophobia, which have tended to be contextually specific, fixed and/or polarized between racism and religious prejudice, between extreme and mainstream, state and non-state versions or undifferentiated, and offer a more nuanced framework to: (a) delineate articulations of Islamophobia as opposed to precise types and categories; (b) highlight the porosity in the discourse between extreme articulations widely condemned in the mainstream, and normalized and insidious ones, which the former tend to render more acceptable in comparison; (c) map where these intersect in response to events, historical and political conditions and new ideological forces and imperatives and (d) compare these articulations of Islamophobia in two contexts, France and the US.     

Studies on the heterogeneity of the 5′ ends of the protamine mRNAs from rainbow trout testis

The structures of the 5' termini of the protamine mRNAs (PmRNAs) have been investigated by inhibiting their translation in wheat-germ extracts in the presence of 7-methyl guanosine 5'-phosphate (m⁷GMP), an analogue of cap structure in mRNAs. Second, the cap structures on PmRNAs were examined by labelling the RNA at the 5' end with T₄ polynucleotide kinase and [-³²p]ATP before and after removal of these structures with tobacco acid pyrophosphatase and alkaline phosphatase. The results indicate that cap structures of the PmRNAs are heterogeneous. It appears that the mRNAs coding Ior protamine components C_I and C_III have at least a cap 1 structure while the mRNAs coding for C_II do not appear to be capped or methylated.     

The anatomy of the solute Girvanicystis batheri (?Chordata) from the Upper Ordovician of Scotland and a new species of Girvanicystis from the Upper Ordovician of South Wales

Detailed anatomical study of the solute Girvanicystis batheri from the Girvan starfish bed (Ashgill) has enabled the oral partition, hydropore, gonopore and the possible opening of a branchial slit to be identified. The distal part of the alimentary tract and the stomach were located in the posterior part of the head. Structures preserved as steinkernen are interpreted as a brain and left cranial nerve. The gross anatomy of G. batheri supports the hypothesis that it was a suspension feeder. Girvanicystis batheri is characterized by large plates on the dorsal surface of the head, 20 rings of the feeding arm and a nodular median plate on the ventral surface of the head. A new species of Girvanicystis, G. casteri , is described from the Sholeshook limestone (Ashgill) of South Wales. Girvanicystis casteri is distinguished from G. batheri in that the former has narrower head, a longer feeding arm and a spine on the median plate of the ventral surface of the head. Girvanicystis batheri has characters in common with the cornute Ceratocystis perneri , namely large plates of the skeleton of the head, right and left marginal flanges, opposite dorsal fore tail plates and alternate ventral fore tail plates, which suggest that G. batheri may also be a stem chordate.     

Evaluation of the Vitek-MS™ system in the identification of Candida isolates from bloodstream infections

Background

Matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF-MS) represents a revolution in the identification of microorganisms of clinical interest. Many studies have confirmed the accuracy and fastness of this tool with routine strains.

A method for the isolation of segments from the 5′ ends of retrovirus RNA

A method for the isolation of segments of any desired length from the 5′ end of retrovirus RNA has been tested. The method is based on selection of 5′-specific segments by hybridizing suitably fragmented genomic (35 S) RNA to mercurated strong stop cDNA followed by chromatography on sulfhydryl-agarose. The method has been shown to be effective for Akv viral RNA by observing the T1 oligonucleotide fingerprints of a 5′-enriched fraction. This fingerprint pattern is of lower complexity than that of total 35 S RNA, contains oligonucleotide spots that have previously been assigned as 5′ specific by conventional fingerprinting methods, and does not overlap with the pattern from 3′-specific RNA.     

α-Glucosidase-inhibitory iminosugars from the leaves of Suregada glomerulata

A water extract of the leaves of Suregada glomerulata (Euphorbiaceae) was found to inhibit rat small intestinal α-glucosidase. An examination of the extract afforded 20 iminosugars including one pyrrolidine and 19 piperidines. The structures of the 10 new compounds (11–20) were determined by NMR, and MS spectroscopic data analyses, and chemical correlations. The novelty of the identified compounds mainly stems from the loss of a hydroxy at C-4 and the presence of an 8-hydroxyoctyl side chain. Nine N-alkyl derivatives including N-methyl (1a, 8a, and 13a), N-butyl (1b, 2b, and 9b) and N,N-dimethyl (1c, 2c, and 9c) were synthesized. The compounds were tested for rat small intestinal α-glucosidase inhibitory activity. In total, 15 compounds, including compounds 11, 12, 15, and 19 and the three derivatives 8a, 9b, and 13a, showed inhibitory activity with IC₅₀ values less than 40 μM. In vivo results showed that total alkaloids of S. glomerulata (10 mg/kg) and four major iminosugars 1, 2, 3, and 9 (10 mg/kg) can lower the postprandial blood glucose level after sucrose and starch load in healthy male ICR mice.     

Transferase reactions of the β-galactosidase from Streptococcus thermophilus

Summary The -galactosidase from Streptococcus thermophilus formed transferase products (including up to six disaccharides and two trisaccharides) during the hydrolysis of lactose to glucose and galactose. The extent of transferase products formed was dependent on the initial lactose concentration, reaching up to 40% of the total carbohydrate at 70% w/v lactose. At high lactose concentrations (40% w/v) trisaccharide transferase products were formed initially, followed by the appearance of disaccharide transferase products. In contrast, at low lactose concentrations (7.5 w/v), only traces of the trisaccharides were detected with disaccharides being the predominant transferase products. The disaccharide products accumulated to relatively high concentrations late in the overall hydrolysis of lactose, at both high and low initial lactose concentrations, while the trisaccharides peaked much earlier and were themselves subsequently hydrolysed prior to the complete disappearance of lactose. It was possible to study the hydrolysis of galactosyl lactose by the S. thermophilus -galactosidase using a semi-pure galactosyl lactose preparation containing 5% lactose. The hydrolysis of this trisaccharide occurred via at least four disaccharide intermidiates, which appeared chromatographically identical to the disaccharide transferase products formed during lactose hydrolysis. This suggests that the enzymic formation and subsequent hydrolysis of galactosyl lactose occurs via coincident reaction pathways. The initial rate of galactose over glucose formation during galactosyl lactose hydrolysis changed from a ratio of 3:1 at low (2–3% w/v) substrate concentrations to 1.5:1 at high (>20% w/v) concentrations. This indicates a shift in the preferred initial cleavage site from the galactose-galactose bond to the galactose-glucose bond.     

Pollen analysis of honeys from the central zone of the Argentine province of Entre Ríos

Based on the melissopalynology 38 honey samples collected in the central region of the Argentine province of Entre Ríos were classified by botanical and geographical origin. According to qualitative analysis, 20 honey samples were monofloral and 18 were multifloral. Dominant pollen types were Scutia buxifolia Reissek (Rhamnaceae) in six samples, Baccharis spp. (Asteraceae) in five, Lotus spp. (Fabaceae) in three, Eucalyptus spp. (Myrtaceae) and Eryngium spp. (Apiaceae) in two, Ammi visnaga (L.) Lam. (Apiaceae) and Trithrinax campestris (Burmeist.) Drude & Griseb. (Arecaceae) in one sample. One hundred and nineteen pollen types were identified belonging to 52 families; 75% of which were native species. The families best represented in number of species were Asteraceae and Fabaceae. Pollen types such as Scutia buxifolia, Trithrinax campestris, Schinus spp. (Anacardiaceae), Mimosoideae from Prosopis spp., Acacia spp., Mimosa ostenii Speg. ex Burkart, and M. strigillosa Torr. & A. Gray are considered the indicators for this geographical origin. The studied honeys were also characterized by a high frequency of Apiaceae, Brassicaceae, Astereae, Echium plantagineum L. and cultivated Papilionoideae forage species such as Melilotus albus Desr., Lotus spp. and Trifolium spp. Honeydew elements were scarce.     

Antiplasmodial β-triketones from the flowers of the Australian tree Angophora woodsiana

Chemical investigations of the MeOH extract of air dried flowers of the Australian tree Angophora woodsiana (Myrtaceae) yielded two new β-triketones, woodsianones A and B (1, 2) and nine known β-triketones (3–11). Woodsianone A is a β-triketone-sesquiterpene adduct and woodsianone B is a β-triketone epoxide derivative. The structures of the new and known compounds were elucidated from the analysis of 1D/2D NMR and MS data. The relative configurations of the compounds were determined from analysis of ¹H–¹H coupling constants and ROESY correlations. All compounds (1–11) had antiplasmodial activity against the chloroquine sensitive strain 3D7. The known compound rhodomyrtone (5) and new compound woodsianone B (2) showed moderate antiplasmodial activities against the 3D7 strain (1.84 µM and 3.00 µM, respectively) and chloroquine resistant strain Dd2 (4.00 µM and 2.53 µM, respectively).     

Anion inhibition profiles of the complete domain of the η-carbonic anhydrase from Plasmodium falciparum

We have cloned, purified and investigated the catalytic activity and anion inhibition profiles of a full catalytic domain (358 amino acid residues) carbonic anhydrase (CA, EC 4.2.1.1) from Plasmodium falciparum, PfCAdom, an enzyme belonging to the η-CA class and identified in the genome of the malaria-producing protozoa. A truncated such enzyme, PfCA1, containing 235 residues was investigated earlier for its catalytic and inhibition profiles. The two enzymes were efficient catalysts for CO₂ hydration: PfCAdom showed a k_cat of 3.8 × 10⁵ s⁻¹ and k_cat/K_m of 7.2 × 10⁷ M⁻¹ × s⁻¹, whereas PfCA showed a lower activity compared to PfCAdom, with a k_cat of 1.4 × 10⁵ s⁻¹ and k_cat/K_m of 5.4 × 10⁶ M⁻¹ × s⁻¹. PfCAdom was generally less inhibited by most anions and small molecules compared to PfCA1. The best PfCAdom inhibitors were sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid, which showed K_Is in the range of 9–68 μM, followed by bicarbonate, hydrogensulfide, stannate and N,N-diethyldithiocarbamate, which were submillimolar inhibitors, with K_Is in the range of 0.53–0.97 mM. Malaria parasites CA inhibition was proposed as a new strategy to develop antimalarial drugs, with a novel mechanism of action.     

Crystal structure of the glycosyltransferase SnogD from the biosynthetic pathway of nogalamycin in Streptomyces nogalater

The glycosyltransferase SnogD from Streptomyces?nogalater transfers a nogalamine moiety to the metabolic intermediate 3',4'-demethoxynogalose-1-hydroxynogalamycinone during the final steps of biosynthesis of the aromatic polyketide nogalamycin. The crystal structure of recombinant SnogD, as an apo-enzyme and with a bound nucleotide, 2-deoxyuridine-5'-diphosphate, was determined to 2.6?? resolution. Reductive methylation of SnogD was crucial for reproducible preparation of diffraction quality crystals due to creation of an additional intermolecular salt bridge between methylated lysine residue Lys384 and Glu374* from an adjacent molecule in the crystal lattice. SnogD is a dimer both in solution and in the crystal, and the enzyme subunit displays a fold characteristic of the GT-B family of glycosyltransferases. Binding of the nucleotide is associated with rearrangement of two active-site loops. Site-directed mutagenesis shows that two active-site histidine residues, His25 and His301, are critical for the glycosyltransferase activities of SnogD both in?vivo and in?vitro. The crystal structures and the functional data are consistent with a role for His301 in binding of the diphosphate group of the sugar donor substrate, and a function of His25 as a catalytic base in the glycosyl transfer reaction. Database The atomic coordinates and structure factors have been deposited with the RCSB Protein Data Bank under accession numbers 4AMB, 4AMG and 4AN4 Structured digital abstract ? snogD?and?snogD?bind?by?x-ray crystallography?(View Interaction:?1,?2).