Viscidic acid A and B,two ent-labdane derivatives from Chrysothamnus viscidiflorus

The chemical investigation of Chrysothamnus viscidiflorus afforded, in addition to known bisabolene derivatives, elemicin and p-hydroxyacetophenone, two new diterpene acids. Their structures were determined, by spectroscopic methods and some chemical transformations, as ent-labd-8(17),13E-dien-15-ol-18-oic acid (viscidic acid A) and ent-labd-8(17),13E-dien-15-acetoxy-18-oic acid (visidic acid B).     

Germacranolides,calbertolides A,B and C,from Calea berteriana

The isolation and structure elucidation of two germacranolides, calbertolides A and B, and a heliangolide, calbertolide C, from Calea berteriana are reported. The structures of the new compounds were established by spectroscopic methods.     

Comparison of Conventional Methods, the R/B System, and Modified R/B System as Guides to the Major Divisions of Enterobacteriaceae

Primary grouping of more than 2,000 members of Enterobacteriaceae, freshly isolated from clinical specimens, was performed on the basis of eight conventional laboratory tests used routinely in this laboratory and by the R/B system. Results indicate that both systems perform well in this first step in the identification of various medically significant species of the family. Difficulties encountered with certain reactions of the R/B system were corrected with a physical modification of the tubes. An additional 100 representatives of Enterobacteriaceae were compared with conventional methods and the modified R/B system. Results indicate improvement in observing and interpreting findings with the R/B system.     

Three new melampolide sesquiterpenes,polymatin A,B and C,from Polymnia maculata Cav. var. maculata

Three new melampolide type sesquiterpene lactones were isolated from Polymnia maculata Cav. var. maculata. Their structures were determined by spectroscopic and chemical means. Based on the presently available chemical data, the chemotaxonomic position of Polymnia within the subtribe is discussed.     

Lasiocarpin A,B and C,three novel phenolic triglycerides from Populus lasiocarpa

The lipophilic excretion of winter buds of many species of Populus contains a variety of flavonoid aglycones. In Populus lasiocarpa, however, neither flavonoids nor free phenolic acids have been detected. Instead we found 3 novel phenolic triglycerides as major components of bud exudate in this species. Their structures have been shown by spectral and chemical evidence to be 1,3-di-p-coumaryl-2-acetyl glycerol, 1-p-coumaryl-3-caffeyl-2-acetyl glycerol, or its antipode, and 1,3-di-caffeyl-2-acetyl glycerol.     

Burkholderia species in human infections in Mexico: Identification of B. cepacia,B. contaminans,B. multivorans,B. vietnamiensis,B. pseudomallei and a new Burkholderia species

BackgroundBurkholderia sensu stricto is comprised mainly of opportunistic pathogens. This group is widely distributed in the environment but is especially important in clinical settings. In Mexico, few species have been correctly identified among patients, most often B. cepacia is described.Methodology/Principal findingsIn this study, approximately 90 strains identified as B. cepacia with the VITEK2 system were isolated from two medical centers in Mexico City and analyzed by MLSA, BOX-PCR and genome analysis. The initial identification of B. cepacia was confirmed for many strains, but B. contaminans, B. multivorans and B. vietnamiensis were also identified among clinical strains for the first time in hospitals in Mexico. Additionally, the presence of B. pseudomallei was confirmed, and a novel species within the B. cepacia complex was documented. Several strains misidentified as B. cepacia actually belong to the genera Pseudomonas, Stenotrophomonas and Providencia.Conclusions/SignificanceThe presence of different Burkholderia species in Mexico was confirmed. Correct identification of Burkholderia species is important to provide accurate treatment for immunosuppressed patients.     

Tetraludin A,B and C,three new melampolides from Tetragonotheca ludoviciana

The investigation of the roots of the four Tetragonotheca species, T. ludoviciana, T. repanda, T. texana and T. helianthoides, resulted in the isolation of the known heptadeca-2-(Z)-8,10-(E)-16-tetraene-4,6-diin-1-ol and its aldehyde derivative from all four species. Aerial parts of T. ludoviciana also contained the acetate of the latter compound as a minor constituent and provided three new melampolide-type sesquiterpene lactones, tetraludin A, B and C.     

Coatline A and B,two C-glucosyl-α-hydroxydihydrochalcones from Eysenhardtia polystachya

The first two examples of naturally occurring C-glucosyl-α-hydroxydihydrochalcones have been isolated from Eysenhardtia polystachya, a Mexica     

Dulcosides A and B,new diterpene glycosides from Stevia rebaudiana

New diterpene glycosides, dulcosides A and B were isolated from Stevia rebaudiana Bertoni and their structures were established as 19-O-β-glu     

Differentiation of Bacillus anthracis, B. cereus, and B. thuringiensis by Using Pulsed-Field Gel Electrophoresis

A pulsed-field gel electrophoresis (PFGE) method was developed for discriminating Bacillus anthracis from B. cereus and B. thuringiensis. A worldwide collection of 25 B. anthracis isolates showed high-profile homology, and these isolates were unambiguously distinguished from B. cereus and B. thuringiensis isolates by cluster analysis of the whole-genome macrorestriction enzyme digestion patterns generated by NotI.     

Genomic Pathology of SLE-Associated Copy-Number Variation at the FCGR2C/FCGR3B/FCGR2B Locus

Reduced FCGR3B copy number is associated with increased risk of systemic lupus erythematosus (SLE). The five FCGR2/FCGR3 genes are arranged across two highly paralogous genomic segments on chromosome 1q23. Previous studies have suggested mechanisms for structural rearrangements at the FCGR2/FCGR3 locus and have proposed mechanisms whereby altered FCGR3B copy number predisposes to autoimmunity, but the high degree of sequence similarity between paralogous segments has prevented precise definition of the molecular events and their functional consequences. To pursue the genomic pathology associated with FCGR3B copy-number variation, we integrated sequencing data from fosmid and bacterial artificial chromosome clones and sequence-captured DNA from FCGR3B-deleted genomes to establish a detailed map of allelic and paralogous sequence variation across the FCGR2/FCGR3 locus. This analysis identified two highly paralogous 24.5 kb blocks within the FCGR2C/FCGR3B/FCGR2B locus that are devoid of nonpolymorphic paralogous sequence variations and that define the limits of the genomic regions in which nonallelic homologous recombination leads to FCGR2C/FCGR3B copy-number variation. Further, the data showed evidence of swapping of haplotype blocks between these highly paralogous blocks that most likely arose from sequential ancestral recombination events across the region. Functionally, we found by flow cytometry, immunoblotting and cDNA sequencing that individuals with FCGR3B-deleted alleles show ectopic presence of FcγRIIb on natural killer (NK) cells. We conclude that FCGR3B deletion juxtaposes the 5′-regulatory sequences of FCGR2C with the coding sequence of FCGR2B, creating a chimeric gene that results in an ectopic accumulation of FcγRIIb on NK cells and provides an explanation for SLE risk associated with reduced FCGR3B gene copy number.     

Tetraphyllin B from Adenia digitata

Tetraphyllin B has been isolated in good yield from the South African plant Adenia digitata. Its structure was established by ¹H and ¹³C NMR.     

Diterpene acids from Helianthus species and their microbiological conversion by Gibberella fujikuroi, mutant B1-41a

The diterpene acid content in 10 species of Helianthus has been investigated. Ent-12,16-cyclokauranoic acid, isolated from H. annuus, is converted into a series of 12,16-cyclogibberellins by cultures of Gibberella fujikuroi, mutant B1-41a, and 12,16-cyclogibberellins A₉, and A₁₂ have been isolated. Ent-12β-acetoxykaurenoic acid and ent-13(S)-angeloxyatisenoic acid have been isolated from H. decapetalus; the metabolism of ent-13(S)-hydroxyatisenoic acid and atisenoic acid by B1-41a is also described.     

Aspernolides A and B, butenolides from a marine-derived fungus Aspergillus terreus

Two aromatic butenolides, aspernolides A and B along with the known metabolites, butyrolactone I, terrein and physcion were isolated from the fermentation broth of a soft coral derived fungus Aspergillus terreus. The structures of these metabolites were assigned on the basis of detailed spectroscopic analysis. The absolute stereochemistry of aspernolides A (1) and B (2) was established by their preparation from the known butyrolactone I. Biogenetically aspernolides A and B must be derived from butyrolactone I, a well known specific inhibitor of cyclin dependent kinase (cdk) from A. terreus. When tested, aspernolide A exhibited mild cytotoxicity against cancer cell lines.     

Alstonic acids A and B, unusual 2,3-secofernane triterpenoids from Alstonia scholaris

2,3-Secofernane triterpenoids, alstonic acids A (1) and B (2), were isolated from the leaves of Alstonia scholaris together with an indole alkaloid, N¹-methoxymethyl picrinine (3). Their structures were established from MS and NMR spectroscopic analyses and confirmed by single crystal X-ray diffraction analysis.     

Production of Beauvericin, Moniliformin, Fusaproliferin, and Fumonisins B1, B2, and B3 by Fifteen Ex-Type Strains of Fusarium Species

Fifteen Fusarium species were analyzed by high-performance liquid chromatography for the production of six mycotoxins in corn grits cultures. Production of mycotoxins ranged from 66 to 2,500 μg/kg for fumonisin B₁, 0.6 to 1,500 μg/g for moniliformin, 2.2 to 720 μg/g for beauvericin, and 12 to 130 μg/g for fusaproliferin. Fumonisin B₂ (360 μg/kg) was produced by two species, fumonisin B₃ was not detected in any of the 15 species examined, and Fusarium bulbicola produced none of the six mycotoxins that we analyzed.     

Affinity chromatography of Aspergillus acid proteinase on an N,O-dibenzyloxycarbonyl-tyrosine-AH-Sepharose 4B column

N,O-dibenzyloxycarbonyl-l-tyrosine Z-Tyr(Z) has been found to be a specific inhibitor of Aspergillus acid proteinase and was coupled with hexamethylene-diamino-Sepharose 4B (AH-Sepharose 4B). By affinity chromatography employing a Z-Tyr(Z)-AH-Sepharose 4B column, acid car?ypeptidase-free Aspergillus acid proteinase was obtained.     

Response of the Microaerophilic Bifidobacterium Species, B. boum and B. thermophilum, to Oxygen

We investigated the effects of O₂ on Bifidobacterium species using liquid shaking cultures under various O₂ concentrations. Although most of the Bifidobacterium species we selected showed O₂ sensitivity, two species, B. boum and B. thermophilum, demonstrated microaerophilic profiles. The growth of B. bifidum and B. longum was inhibited under high-O₂ conditions accompanied by the accumulation of H₂O₂ in the medium, and growth was restored by adding catalase to the medium. B. boum and B. thermophilum grew well even under 20% O₂ conditions without H₂O₂ accumulation, and growth was stimulated compared to anoxic growth. H₂O-forming NADH oxidase activities were detected dominantly in cell extracts of B. boum and B. thermophilum under acidic reaction conditions (pH 5.0 to 6.0).     

Dianthramides A and B,two N-benzoylanthranilic acid derivatives from elicited tissues of Dianthus caryophyllus

Two new phenolic derivatives, dianthramide A and B, were isolated from Dianthus caryophyllus tissues elicited with mycelial extracts of Phytophthora parasitica. The purified substances were identified on the basis of their spectral data and were characterized as N-salicyl-4-methoxyanthranilic acid (dianthramide A) and N-salicyl-4-hydroxyanthranilic acid methyl ester (dianthramide B). Dianthramides A and B co-occur in carnation tissues with the known phytoalexin dianthalexin.     

Tanacetols A and B,non-volatile sesquiterpene alcohols,from Tanacetum vulgare

Chemical investigation of a rare chemotype of Tanacetum vulgare attorded a series of non-volatile sesquiterpene alcohols which have been called tanacetols. The structures of tanacetols A and B, the two most abundant, have been established on the basis of spectroscopic data, chemical reactions and X-ray diffraction analysis of tanacetol A and tanacetol B acetate.