Genomics-Based Insights Into the Biosynthesis and Unusually High Accumulation of Free Fatty Acids by Streptomyces sp NP10

Schneider O, Ilic-Tomic T, Rückert C, et al. Genomics-Based Insights Into the Biosynthesis and Unusually High Accumulation of Free Fatty Acids by Streptomyces sp NP10. FRONTIERS IN MICROBIOLOGY. 2018;9: 10.Streptomyces sp. NP10 was previously shown to synthesize large amounts of free fatty acids (FFAs). In this work, we report the first insights into the biosynthesis of these fatty acids (FAs) gained after genome sequencing and identification of the genes involved. Analysis of the Streptomyces sp. NP10 draft genome revealed that it is closely related to several strains of Streptomyces griseus. Comparative analyses of secondary metabolite biosynthetic gene clusters, as well as those presumably involved in FA biosynthesis, allowed identification of an unusual cluster C12-2, which could be identified in only one other S. griseus-related streptomycete. To prove the involvement of identified cluster in FFA biosynthesis, one of its three ketosynthase genes was insertionally inactivated to generate mutant strain mNP10. Accumulation of FFAs in mNP10 was almost completely abolished, reaching less than 0.01% compared to the wild-type strain. Cloning and transfer of the C12-2 cluster to the mNP10 mutant partially restored FFA production, albeit to a low level. The discovery of this rare FFA biosynthesis cluster opens possibilities for detailed characterization of the roles of individual genes and their products in the biosynthesis of FFAs in NP10

Average mass scan of the total ion chromatogram versus percentage chemical composition in multivariate statistical comparison of complex volatile mixtures

The analysis of complex volatile mixtures by gas chromatography-mass spectrometry (GC-MS) is a time-consuming process. It involves separation and identification of the components based on their retention times and fragmentation patterns, followed by determination of their relative percentages from integration of their peak areas. Herein we show that multivariate statistical analysis of the relative abundances of the m/z values obtained from the average mass scans (AMS) of the complex mixture is a faster and potentially more reliable method of assessing these mixtures. To achieve this, 15 model complex mixtures, were prepared comprising varying amounts of 10 different constituents. The AMS profile and chemical composition of each mixture were compared to one another using agglomerative hierarchical cluster analysis and principal component analysis. The results obtained strongly suggest that multivariate statistical analysis of AMS profiles is a promising, time saving and reliable tool for analyzing complex volatile mixtures, in particular essential oils

Fatty and volatile oils of the gypsywort lycopus europaeus L. and the gaussian-like distribution of its wax alkanes

The detailed analyses of the volatile essential oil and lipid profiles of the aerial parts from the blooming and fruit-forming stages of both ripe and unripe fruit of Lycopus europaeus (Lamiaceae) are presented. Both of these profiles are distinguished by components with a restricted occurrence in the Plant Kingdom. These rare compounds include (E)-hotrienol in the volatiles, numerous unusual fatty acids (such as very long chain, odd-numbered and branched-chain) in the bound lipids and a high amount of iso- and anteiso-alkanes in the epicuticular waxes. Furthermore, a Gaussian-like distribution of the relative amounts of the epicuticular wax alkanes was observed. These normal distributions could be interpreted as the end result of the work of elongase enzyme systems where the Gaussian parameter μ should match the length of the “ideal” fatty acid biosynthesised and σ would represent the error of this enzyme system. These curve parameters were shown to have a close relationship with ACL and CPI values usually utilised to describe the natural distribution of wax alkanes. The screening of L. europaeus essential oil for its in vitro antimicrobial activity showed that this oil possesses selectivity towards two gram-negative strains, E. coli and K. pneumoniae

REDUKCIJA5-ACETIL-1,6-DIMETIL-4-FENIL-3,4-DIHIDROPIRIMIDIN-2(1H)-ONA LITIJUM-ALUMINIJUM-HIDRIDOM

In this paper, we investigated the LiAlH4-reduction of 5-acetyl-1,6-dimethyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-one (N-methylated Biginelli compound). Following the reduction and SiO2-promoted dehydration, (Z)-5-ethylidene-1-methyl-6-methylene-4-phenyltetrahydropyrimidin-2(1H)-one was isolated as the major product (33% yield). Chromatographic separation of the reaction products also allowed us to isolate (yield in parentheses) and fully spectrally characterize: 1,6-dimethyl-4-phenyl-5-vinyl-3,4-dihydropyrimidin-2(1H)-one (20%), 5-ethyl-1,6-dimethyl-4-phenyl-3,4-dihydro-pyrimidin-2(1H)-one (9%), 5-(1-hydroxyethyl)-1,6-dimethyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-one (5%). A possible mechanism explaining the formation of these products is proposed.U ovom radu ispitana je redukcija 5-acetil-1,6-dimetil-4-fenil-3,4-dihidropirimidin-2(1H)-ona (N-metilovanog Biđinelijevog proizvoda) litijum-aluminijum-hidridom. Kao najzastupljeniji proizvod reakcije, nakon redukcije I dehidratacije na silica gelu, izolovan je (Z)-5-etiliden-1-metil-6-metilen-4-feniltetrahidropirimidin-2(1H)-on u prinosu od 33%. Hromatografskim razdvajanjem prečišćeni su I ostali proizvodi:4-fenil-1,6-dimetil-5-vinil-3,4-dihidropirimidin-2(1H)-on (prinos: 20%), 5-etil-1,6-dimetil-4-fenil-3,4-dihidropirimidin-2(1H)-on (9%) i5-(1-hidroksietil)-1,6-dimetil-4-fenil-3,4-dihidropirimidin-2(1H)-on (5%). Predložen je mogući mehanizam koji objašnjava nastajanje ovih proizvoda

Misidentification of tansy, tanacetum macrophyllum, as yarrow, achillea grandifolia: a health risk or benefit?

Tansy, Tanacetum macrophyllum (Waldst. & Kit.) Sch. Bip., is often misidentified by herb collectors as yarrow, Achillea grand folia Friv. With the former, cases of poisoning induced by its ingestion are well documented, but the latter is widely used for ethnopharmacological purposes. The aim of this study was to estimate, based on the volatile metabolite profiles of the two species, the potential health risk connected with their misidentification. GC and GC-MS analysis of the essential oils hydrodistilled using a Clevenger-type apparatus from A. grandifolia, T macrophyllum, and two plant samples (reputedly of A. grandifolia, but in fact mixtures of A. grand folia and T macrophyllum) obtained from a local market, resulted in the identification of 215 different compounds. The main constituents of A. grandifolia oil were ascaridole (15.5%), alpha-thujone (7.5%), camphor (15.6%), borneol (5.2%) and (Z)-jasmone (6.4%), and of T macrophyllum oil, 1,8-cineole (8.6%), camphor (6.4%), borneol (9.1%), isobornyl acetate (9.5%), copaborneol (4.2%) and gamma-eudesmol (6.2%). The compositions of the oils extracted from the samples obtained from the market were intermediate to those of A. grandifolia and T macrophyllum. Significant differences in the corresponding volatile profiles and the literature data concerning the known activities of the pure constituents of the oils, suggested that the pharmacological action of the investigated species (or their unintentional mixtures) would be notably different. It seems, however, that misidentification of T macrophyllum as A. grandifolia does not represent a health risk and that the absence of the toxic alpha-thujone from T macrophyllum oil may in fact be regarded as a benefit

Chemotaxonomy of the peppergrass Lepidium coronopus (L.) Al-Shehbaz (syn. Coronopus squamatus) based on its volatile glucosinolate autolysis products

The genus Lepidium comprises approximately 175 different plant species commonly referred to as peppergrasses or pepperworts ( Al-Shehbaz, 1997 and Mummenhoff et al., 2001), which occur worldwide apart from the polar regions where they are considered rare in the Arctic and are absent from Antarctica. Lepidium is a comparatively large genus belonging to the mustard family Brassicaceae. Lepidium coronopus (L.) Al-Shehbaz, a representative of the genus, is a herbaceous annual to biennial plant that belongs to the tribe Lepidieae and has previously been described by the following synonymous species: Coronopus squamatus (Forsskal) Ascherson; C. squamatus subsp. conradi (Muschler) Maire; C. squamatus subsp. eu-verrucarius Maire; Coronopus procumbens Cesati & al.; Coronopus ruellii All.; Coronopus verrucarius Muschler & Thell; Lepidospartum squamatum Forsskål; Senebiera coronopus (L.) Poiret; and Cochlearia coronopus L

Crystal structure of 3-cyclohexyl-1,3-oxazinan-2-one, C <inf>10</inf>H <inf>17</inf>NO <inf>2</inf>

C 10H 17NO 2,monoclinic, P12 1/cl (no. 14), a = 10.187(1) Å, b = 9.8426(8) Å, c = 10.766(1) Å, β = 113.589(4)°, V = 989.3 Å 3, Z = 4, R gt(F) = 0.051, wR ref(F 2) = 0.143, T=295 K. © by Oldenbourg Wissenschaftsverlag, München

Antioxidant, antimicrobial and genotoxicity screening of hydro-alcoholic extracts of five serbian Equisetum species

The hydro-alcoholic extracts of five Equisetum species, E. arvense L., E. sylvaticum L., E. fluviatile L., E. palustre L. and E. telmateia Ehrh., growing-wild in Serbia were evaluated for their genotoxicity, antimicrobial activity, antioxidant capacity and the results related to the total phenol content and HPLC flavonoid profiles. The total phenol content was 92-349 mu mol expressed as equivalents of chlorogenic acid per g of dried plant material. Main identified compounds were kaempferol-, quercetin- glycosides and caffeic acid derivatives. E. telmateia extract showed the greatest antioxidant capacity. Almost all tested microorganisms demonstrated some degree of sensitivity to the examined extracts. All tested extracts at 62.5 mu g/ml showed higher incidence of micronucleus formation than in the control sample. The obtained data allowed mutual comparison of examined species and their assessment as possible sources of antioxidants, antimicrobials and/or genotoxic substances