Three anamorphic yeast species Candida sanitii sp. nov., Candida sekii sp. nov. and Candida suwanaritii, three novel yeasts in the Saturnispora clade isolated in Thailand

Nine strains of three novel anamorphic yeast species were obtained from samples collected in Thailand including six strains (RV96, RV152, R14, RS9, RS58 and EA1) obtained from estuarine waters collected from two mangrove forests, one strain (ST84) from insect frass and two strains (SR16 and UB13) from forest soils. On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics, and the sequence analysis of the D1/D2 domain of the large subunit rRNA gene, the nine strains were found to represent three novel Candida species in the Saturnispora clade. Five strains (RV96, RV152, R14, RS9 and RS58) were assigned as a single novel species, which was named Candida sanitii sp. nov. The type strain is RV152^T (BCC 25967^T=NBRC 103864^T=CBS 10864^T). Strain EA1 was named as Candida suwanaritii sp. nov. The type strain is EA1^T (BCC 29900^T=NBRC 104877^T=CBS 11021^T). Three strains (ST84, SR16 and UB13) represented another novel species, for which Candida sekii sp. nov. is proposed. The type strain is ST84^T (BCC 8320^T=NBRC 105671^T=CBS 10931^T).     

Potential anti-inflammatory diterpenoids from the roots of Caesalpinia mimosoides Lamk.

Anti-inflammatory assay-guided separation of extracts from the roots of Caesalpinia mimosoides Lamk. led to isolation of seven compounds: four diterpenes (1–4), a dimer (9), and two dibenzo[b,d]furans (10, 11) together with eleven known compounds. Their structures were elucidated by 1D- and 2D-NMR techniques as well as UV, IR, mass spectral data and comparison with literature values. The anti-inflammatory activities of all compounds were evaluated for inhibitory activities against lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW264.7 cell lines. Compounds 4, 6, 8, and 12–14 were also tested for the inhibitory effect on LPS-induced tumor necrosis factor-alpha (TNF-α) release in RAW264.7 cells. The results indicated that 4 possessed potent inhibitory activity for both tests with IC₅₀ values of 3.0 and 6.5 μM, respectively.     

Potential anti-allergic acridone alkaloids from the roots of Atalantia monophylla

Acridone alkaloids, cycloatalaphylline-A (1), N-methylcyclo-atalaphylline-A (2) and N-methylbuxifoliadine-E (3), were isolated from the dichloromethane and acetone extracts of the root of Atalantia monophylla along with eight known acridone alkaloids: buxifoliadine-A (4), buxifoliadine-E (5), N-methylatalaphylline (6), atalaphylline (7), citrusinine-I (8), N-methylataphyllinine (9), yukocitrine (10) and junosine (11) and two known coumarins: auraptene (12) and 7-O-geranylscopoletin (13). Their structures were elucidated on the basis of spectroscopic analyses. Compounds 2, 5 and 8 possessed appreciable anti-allergic activity in RBL-2H3 cells model with IC(50) values of 40.1, 6.1 and 18.7 microM, respectively.     

Potential anti-allergic ent-kaurene diterpenes from the bark of Suregada multiflora

Two ent-kaurene diterpenes, ent-16-kaurene-3beta,15beta,18-triol (1) and ent-3-oxo-16-kaurene-15beta,18-diol (2), were isolated from a dichloromethane extract of the bark of Suregada multiflora along with five known diterpenes:ent-16-kaurene-3beta,15beta-diol (3), abbeokutone (4), helioscopinolide A (5), helioscopinolide C (6) and helioscopinolide I (7). Their structures were elucidated on the basis of spectroscopic analysis. Compounds 1-7 possessed appreciable anti-allergic activities in RBL-2H3 cells model with IC50 values ranging from 22.5 to 42.2 microM.     

Phanginin A-K, diterpenoids from the seeds of Caesalpinia sappan Linn

The first chemical study on the seeds of Caesalpinia sappan Linn. led to isolation of 11 cassane-type diterpenes, named phanginin A-K (1-11). The skeleton present in compounds 1-8 is rather unusual, consisting of a cassane-type diterpene with an ether bridge between C-19/C-20 in compounds 1-6 and C-11/C-20 in compounds 7 and 8. Their structures were elucidated on the basis of spectroscopic techniques. In addition, the X-ray structure of phanginin A (1) is reported. Only phanginin I (9) exhibited cytotoxic effect against KB cell line with IC50 value of 4.4 microg/ml.     

Cloning and expression of three ladA-type alkane monooxygenase genes from an extremely thermophilic alkane-degrading bacterium Geobacillus thermoleovorans B23

An extremely thermophilic bacterium, Geobacillus thermoleovorans B23, is capable of degrading a broad range of alkanes (with carbon chain lengths ranging between C11 and C32) at 70 °C. Whole-genome sequence analysis revealed that unlike most alkane-degrading bacteria, strain B23 does not possess an alkB-type alkane monooxygenase gene. Instead, it possesses a cluster of three ladA-type genes, ladAα_B23, ladAβ_B23, and ladB _B23, on its chromosome, whose protein products share significant amino acid sequence identities, 49.8, 34.4, and 22.7 %, respectively, with that of ladA alkane monooxygenase gene found on a plasmid of Geobacillus thermodetrificans NG 80-2. Each of the three genes, ladAα_B23, ladAβ_B23, and ladB _B23, was heterologously expressed individually in an alkB1 deletion mutant strain, Pseudomonas fluorescens KOB2Δ1. It was found that all three genes were functional in P. fluorescens KOB2Δ1, and partially restored alkane degradation activity. In this study, we suggest that G. thermoleovorans B23 utilizes multiple LadA-type alkane monooxygenases for the degradation of a broad range of alkanes.     

Anti-HIV-1 protease activity of compounds from Boesenbergia pandurata

Searching for anti-HIV-1 protease (PR) inhibitors of Thai medicinal plants led to the isolation of a new cyclohexenyl chalcone named panduratin C (1) and chalcone derivatives (2-6) from the methanol extract of Boesenbergia pandurata rhizomes. The known compounds were identified to be panduratin A (2), hydroxypanduratin A (3), helichrysetin (4), 2',4',6'-trihydroxyhydrochalcone (5), and uvangoletin (6). The structures of all compounds were elucidated on the basis of chemical and spectroscopic methods. It was found that 3 possessed the most potent anti-HIV-1 PR activity with an IC50 value of 5.6 microM, followed by 2 (IC50 = 18.7 microM), whereas other compounds exhibited only mild activity. Structure-activity relationships of these compounds on anti-HIV-1 PR activity are summarized as follows: (1) hydroxyl moiety at position 4 conferred higher activity than methoxyl group; (2) prenylation of dihydrochalcone was essential for activity; (3) hydroxylation at position 4' reduced activity; and (4) introduction of double bond at C1' and C6' of chalcone gave higher activity. As regards active constituents contained in B. pandurata rhizomes, hydroxypanduratin A (3) and panduratin A (2) are active principles against HIV-1 PR.     

Cassane diterpenoids from the stem of Caesalpinia pulcherrima

Cassane diterpenoids: pulcherrin A, pulcherrin B, pulcherrin C, neocaesalpin P, neocaesalpin Q and neocaesalpin R, together with eight known compounds: isovouacapenol C, 6β-cinnamoyl-7β-hydroxy-vouacapen-5α-ol, pulcherrimin E, pulcherrimin C, α-cadinol, 7-hydroxycadalene, teucladiol and bonducellin were isolated from the stem of Caesalpinia pulcherrima. The chemical structures were elucidated by analysis of their spectroscopic data.     

Candida siamensis sp. nov., an anamorphic yeast species in the Saturnispora clade isolated in Thailand

Three strains of a novel anamorphic yeast species were isolated from natural samples collected in Thailand, including strain EF10 isolated from sediment in a mangrove forest, strain ST-473 from rotten wood, and strain ST-479 from a wild mushroom ( Hygrophorus sp.). Analysis of the D1/D2 domains of the large-subunit rRNA gene sequence revealed that the sequence of strain EF10 differed from the other two strains (ST-473 and ST-479), which had identical sequences, by only one nucleotide (nt) substitution in 535 nt. The closest species in terms of pairwise sequence similarity was Saturnispora mendoncae , with 32 nt substitutions and seven gaps in 535 nt. Phylogenetic analysis demonstrated that the three strains form a cluster with S. mendoncae and the other eight species in the Saturnispora clade. Phenotypic characteristics of the three strains were the same including proliferation by multilateral budding, absence of ascospores and negative diazonium blue B and urease reactions. The major ubiquinone was Q-7. On this basis, the three strains were assigned to a single novel species of the genus Candida , for which the name Candida siamensis sp. nov. is proposed. The type strain is EF10^T (=BCC 29901^T=NBRC 104878^T=CBS 11022^T).