A new meroterpenoid isolated from roots of Ptaeroxylon obliquum Radlk.

The roots of Ptaeroxylon obliquum Radlk. (Rutaceae) afforded a new meroterpenoid, ptaerobliquol, together with chromones, ptaeroxylinol acetate and peucenin, and coumarins, scopoletin and prenyletin. Ptaerobliquol was isolated using centrifugal partition chromatography followed by silica gel column and identified as 7a,8,9,9a,9b,10a-heptahydro-4H-10,10-dimethyl-1,7-dioxa-5-hydroxy-2-hydroxymethylcyclobutyl[1,2,3:3,3a,4]indeno[5,6-a]naphtalen-4-one by extensive NMR and single crystal X-ray analyses. A biosynthetic pathway is proposed for this new compound. Activity of ptaerobliquol toward Toxoplasma gondii was investigated and a moderate activity was found with an IC₅₀ of 5.13 μM.     

Coumarins from Cedrelopsis grevei (Ptaeroxylaceae)

The stem bark of Cedrelopsis grevei Baill. has yielded the first reported examples of 5-prenylated coumarins, cedrecoumarin A and B as well as the known coumarins, cedrelopsin, scoparone, O-methylcedrelopsin and norbraylin, and the known chromones ptaeroglycol and ptaeroxylinol.     

Secondary metabolites from Cedrelopsis grevei (Ptaeroxylaceae)

From the hexane extract of the stem bark of Cedrelopsis grevei (Ptaeroxylaceae) was isolated the triterpenoid derivative, cedashnine, and the quassinoid, cedphiline, along with cedmiline, scoparone, beta-amyrin and sitosteryl glucoside.     

Cedkathryns A and B, pentanortriterpenoids from Cedrelopsis gracilis (Ptaeroxylaceae)

The stem bark of Cedrelopsis gracilis (Ptaeroxylaceae) has yielded three known prenylated coumarins, O-methylalloptaeroxylin, ptaerochromenol and umtatin and the novel pentanortriterpenoids, cedkathryn A and cedkathryn B.     

Chalcones from the seed of Cedrelopsis grevei (Ptaeroxylaceae)

The seed of Cedrelopsis grevei (Ptaeroxylaceae) has yielded the known compounds uvangoletin, 5,7-dimethylpinocembrin, cardamonin, flavokawin B, 2'-methoxyhelikrausichalcone, and the novel prenylated chalcones, cedreprenone and cedrediprenone. Cedridiprenone has been shown to exhibit superoxide scavenging properties.     

Aminoacylation of an unusual tRNA(Cys) from an extreme halophile

The extreme halophile Halobacterium species NRC-1 overcomes external near-saturating salt concentrations by accumulating intracellular salts comparable to those of the medium. This raises the fundamental question of how halophiles can maintain the specificity of protein-nucleic acid interactions that are particularly sensitive to high salts in mesophiles. Here we address the specificity of the essential aminoacylation reaction of the halophile, by focusing on molecular recognition of tRNA(Cys) by the cognate cysteinyl-tRNA synthetase. Despite the high salt environments of the aminoacylation reaction, and despite an unusual structure of the tRNA with an exceptionally large dihydrouridine loop, we show that aminoacylation of the tRNA proceeds with a catalytic efficiency similar to that of its mesophilic counterparts. This is manifested by an essentially identical K(m) for tRNA to those of the mesophiles, and by recognition of the same nucleotide determinants that are conserved in evolution. Interestingly, aminoacylation of the halophile tRNA(Cys) is more closely related to that of bacteria than eukarya by placing a strong emphasis on features of the tRNA tertiary core. This suggests an adaptation to the highly negatively charged tRNA sugar-phosphate backbone groups that are the key elements of the tertiary core.     

Pensteminoside, an unusual catalpol-type iridoid from Penstemon gentianoides HBK (Plantaginaceae)

From the MeOH and ethyl acetate extracts of aerial parts of Penstemon gentianoides HBK (Plantaginaceae) an unusual iridoid of the catalpol-type, was isolated and characterized as pensteminoside: (8-O-trans-cinnamoyl, 6-hydroxy, 1-[beta-D-glucopyranoside-6'-O-((4'-hydroxy)-cinnamoyl)]-catalpol) was isolated, along with the known iridoids: plantarelanoside and globularisicin, the flavone: luteolin and diosmetin, as well the phenylpropanoids, verbascoside and martynoside. Their structures were established by 1D and 2D NMR spectroscopic analyses.     

Isolation and characterization of an unusual form of L-amino acid oxidase from King cobra (Ophiophagus hannah) venom

The L-amino acid oxidase (EC 1. 4. 3. 2) from King cobra (Ophiophagus hannah) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was determined to be 140000 when examined by gel filtration and 68000 by SDS-polyacrylamide gel electrophoresis. The enzyme had an isoelectric point of 4.5 and an intravenous LD50 of 5 micrograms/g in mice. It is a glycoprotein and contains two moles of FAD per mole of enzyme. The enzyme exhibited unusual thermal stability and unlike most other venom L-amino acid oxidases, it was stable in alkaline solution and was not inactivated by freezing.     

Isolation of the diterpenoid teuflin (6-epiteucvin) from Teucrium viscidum var. miquelianum

The diterpenoid teuflin (6-epiteuevin) has been isolated from Teucrium viscidum var. miquelianum. Its base catalysed epimerization into teucvidin was studied under mild conditions and the pathway is discussed.     

Novel cytogenetic finding: an unusual X;X-translocation in Mehsana buffalo (Bubalus bubalis)

Cytogenetic investigations of a phenotypically normal Mehsana river buffalo calf (Bubalusbubalis) revealed an XXY chromosome complement due to X;X-translocation in all screened metaphase plates. The chromosomal anomaly was identified by GTG-banding while CBG- and RBG-banding revealed two heterochromatin blocks and that one of the two X chromosomes was late replicating, respectively. The normal cytogenetic profiles of sire, dam and relatives of the calf suggest that the anomaly could have arisen spontaneously during oogenesis. This is the first report on a male river buffalo calf having an XXY chromosome complement with translocation between the two X chromosomes.     

Isolation and characterization of an unusual 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase gene from Enterobacter cloacae UW4

A genomic library of the 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing plant growth-promoting bacterium Enterobacter cloacae UW4 in pUC19 in Escherichia coli was screened for the ability to utilize ACC as a sole source of nitrogen. One of the clones that was isolated contained a plasmid with an insert of approximately 0.8 kb that conferred ACC deaminase activity. Sequence analysis revealed that this DNA fragment contains an open-reading frame of 696 nucleotides predicted to encode a protein of 232 amino acids, a member of the amidohydrolase protein superfamily, i.e., a deaminase that contains a mononuclear or binuclear metal center as compared to the canonical ACC deaminase which contains pyridoxal phosphate as a co-factor.     

Isolation of an enterovirus (SV19) from baboons (Papio cynocephalus)

Inoculation of newborn mice with fecal samples from approximately 200 baboons (Papio cynocephalus) yielded an enterovirus (SV19) from four different animals. This virus previously had been found only in Asian monkeys (Macaca sp).     

Isolation of an extracellular proteinase (keratinase) from Microsporum canis

Proteolytic activity was demonstrated when a strain of Microsporum canis was cultured in broth with human hair, but not in the medium without hair. The extracellular proteinase (keratinase) was isolated and purified by chromatography. Disc electrophoresis showed one protein band of extracellular proteinase, and the antibody against this enzyme gave a single precipitin line in agar diffusion. The IgG fraction completely neutralized the proteinase activity. The proteinase of M. canis may play a role in infection caused by this fungus, by affecting keratinized tissue such as stratum corneum and hair.     

Isolation of a novel plant lectin with an unusual specificity from Calystegia sepium

A novel plant lectin has been isolated from the rhizomes of Calystegia sepium (hedge bindweed) and partially characterized. The lectin is a dimeric protein composed of two identical non-covalently linked subunits of 16kDa. Hapten inhibition studies indicate that the novel lectin is best inhibited by maltose and mannose and hence exhibits a sugar binding specificity that differs in some respects from that of all previously isolated plant lectins. Mitogenicity tests have shown that the Calystegia lectin is a powerful T-cell mitogen. Affinity purification of human, plant and fungal glycoproteins on immobilized C. sepium lectin demonstrates that this novel lectin can be used for the isolation of glycoconjugates from various sources. Moreover, it can be expected that by virtue of its distinct specificity, the new lectin will become an important tool in glycobiology. Abbreviations: Calsepa, lectin isolated from Calystegia sepium; ConA, concanavalin A; LPS, lipopolysaccharide; PBS, phosphate buffered saline (1.5 mMKH2PO4, 10 mM Na2HPO4, 3 mM KCl, 140 mM NaCl, pH 7.4) This revised version was published online in November 2006 with corrections to the Cover Date.     

Turner syndrome mosaicism: an unusual case with a de novo large dicentric marker chromosome: mos 45,X/46,X, ter rea(X;X)(p22.3;p22.3)

X/X translocations are quite rare in humans. The effect of this anomaly on the phenotype is variable and depends on the amount of deleted material and whether the chromosomes are joined by their long or short arms. We report an unusual case of Turner syndrome mosaicism in a 16-year-old girl, who was referred to our Institute for primary amenorrhoea associated with short stature. Endocrine evaluation revealed hypergonadotropic hypogonadism, which required a study of the karyotype. Cytogenetic analysis, performed on peripheral blood leucocytes, showed a mos 45,X/46,X,ter rea (X;X)(p22.3;p22.3) de novo karyotype. The prevalent cell line was 45,X (90% cells). A second cell line (10% cells) showed a very large marker chromosome, similar to a large metacentric chromosome. FISH (fluorescent in situ hybridisation) and molecular analysis revealed that the marker chromosome was dicentric and totally derived from the paternal X chromosome.     

New alkamide and ent-kaurane diterpenoid derivatives from Senecio erechtitoides (Asteraceae)

Fractionation of a MeOH/CH₂Cl₂ (1/1) extract of the aerial parts of Senecio erechtitoides led to the isolation of six compounds including the hitherto unknown N-phenethylamide derivative named N-(p-hydroxyphenethyl)pentacosanamide (1), and a kauranoid derivative named derivative named ent-7-oxo-16α,17-dihydroxykauran-19-oic acid (2), as well as four known compounds, ent-Kaur-16-en-19-oic acid (3), ent-7β-hydroxykaur-16-en-19-oic acid (4), ent-7-oxokaur-16-en-19-oic acid (5), steppogenin 4′-O-β-d-glucoside (6). Their structures and relative configurations were elucidated on the basis of spectroscopic methods, chemical reactions, and comparison with previously known analogs. All isolates were evaluated for their antimicrobial activity and only diterpenoids were found to possess a potent inhibitor effect against the range of microorganism.     

Isolation of an unusual metabolite 2-allyloxyphenol from a marine actinobacterium, its biological activities and applications

A marine actinobacterium isolated from the Bay of Bengal, India and previously found to be producing an antimicrobial and cytotoxic terpenoid was further investigated for antimicrobial metabolites. The bacterium was preliminarily identified as a new species of the genus Streptomyces (strain MS1/7). The cell-free culture broth was extracted with n-butanol and purified using silica gel column chromatography and high-performance liquid chromatography. Molecular characterization was done using ESI mass, IR and ¹H and ¹³C NMR spectrometry. 2-Allyloxyphenol (MW 150; C₉H₁₀O₂), a synthetic drug and chemical intermediate, was obtained as a natural product for the first time. Serendipitous natural occurrence provided new insights into the synthetic molecule. 2-Allyloxyphenol was found to be inhibitory to 21 bacteria and three fungi in the minimum range 0.2–1.75 mg mL⁻¹ determined by agar dilution method. 2-Allyoxyphenol possesses strong antioxidant property (IC₅₀ 22 μg mL⁻¹, measured by 1, 1-diphenyl-2-picryl hydrazyl scavenging activity). Hydroxyl and allyloxy groups in 2-allyloxyphenol were responsible for antimicrobial and antioxidant activities. 2-Allyloxyphenol has marked resemblance to smoky aroma and is two to three times more active as an antimicrobial than some commercial smoke-flavour compounds. Absence of hemolytic toxicity, potential carcinogenicity, cytotoxicity and reports of toxic reactions in literature suggest possible application of 2-allyloxyphenol as a food preservative and an oral disinfectant.     

Isolation of a sultone as an unusual acetolysis product

Acetolysis of methyl 5,6-di-O-acetyl-2,3-O-isopropylidene-β-l-gulofuranoside has yielded a sultone, 4-(1,2,5,6-tetra-O-acetyl-β-l-gulofuranos-3-yl)-6-methyl-1,2-oxathiin 2,2-dioxide (2) whose structure was determined by X-ray diffraction. ¹H and ¹³C NMR spectral properties of 2 are presented together with a rationale for its formation. Preparation and properties of the related α-d-mannofuranos-3-yl compound 4 are described.