Atlantinone A, a Meroterpenoid Produced by Penicillium ribeum and Several Cheese Associated Penicillium Species.

Atlantinone A has been isolated from the psychrotolerant fungus Penicillium ribeum. The exact structure of the compound was confirmed by mass spectrometric and 1- and 2D NMR experiments. Atlantinone A was originally only produced upon chemical epigenetic manipulation of P. hirayamae, however in this study the compound was found to be produced at standard growth conditions by the following species; P. solitum, P. discolor, P. commune, P. caseifulvum, P. palitans, P. novae-zeelandiae and P. monticola. A biosynthetic pathway to atlantinone A starting from andrastin A is proposed.

Variation of polyphenols and betaines in aerial parts of young, field-grown Amaranthus genotypes.

Amaranthus hybridus and Amaranthus mantegazzianus are commonly cultivated and the entire young fresh plants consumed as vegetables in regions of Africa and Asia. A. hybridus and A. mantegazzianus were cultivated at four sites in three climate regions of the world: Santa Rosa, Argentina; Lleida, Spain; and Prague and Olomouc, both in the Czech Republic. The contents of flavonoids (isoquercitrin, rutin, nicotiflorin), hydroxybenzoic acids (protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid), hydroxycinnamic acids (caffeic acid, p-coumaric acid, ferulic acid), hydroxycinnamyl amides (N-trans-feruloyltyramine, N-trans-feruloyl-4-O-methyldopamine), and betaines (glycinebetaine, trigonelline) were determined. The variation in phytochemical content due to species and cultivation site was analyzed utilizing the multivariate statistical methods of principal component analysis (PCA) and graphical model (GM). The Argentinean samples differed from the three other locations due to higher contents of most compounds. The samples from Spain and the Czech Republic differed from each other in the content of the negatively correlated metabolites trigonelline and the flavonoids. The two amaranth species were separated primarily by a higher content of trigonelline and the two hydroxycinnamyl amides in A. mantegazzianus. The GM showed that the quantities of the different analytes within each compound group were intercorrelated except in the case of the betaines. The betaines carried no information on each other that was not given through correlations with other compounds. The hydroxycinnamic acids were a key group of compounds in this analysis as they separated the other groups from each other (i.e., carried information on all of the other groups). This study showed the contents of polyphenols and betaines in the aerial parts of vegetable amaranth to be very dependent on growth conditions, but also revealed that some of the compounds (trigonelline and the two hydroxycinnamyl amides) may be useful as features of a taxonomic classification.

Does Pseudomonas fluorescens produce N-mercapto-4-formylcarbostyril?

The claim that N-mercapto-4-formylcarbostyril was isolated from Pseudomonas fluorescens strain G308 is questioned since N-thiols appear to be unstable compounds at ambient temperature.

Cinnamoylphenethylamine 1H-NMR chemical shifts: a concise reference for ubiquitous compounds.

1H-NMR data of 25 cinnamoylphenethylamine derivates were recorded and compared in order to assign signals unequivocally without additional spectroscopic data. The spectra provide a key for the rapid identification of these ubiquitous natural products. The compounds isomerize rapidly in UV light, producing a characteristic upfield shift of the olefinic protons consistent with distorted planarity of the cis cinnamate, and this requires special attention during preparative work.

Synthesis and quantitation of six phenolic amides in Amaranthus spp.

Cinnamoylphenethylamines are phenolic amides in which cinnamic acid provides the acid moiety and phenethylamine the amine moiety. Single ion monitoring (SIM) in LC-MS was performed on amaranth leaf extracts. Masses corresponding to sets of regioisomers, including previously reported compounds, were examined. Six peaks were detected and their corresponding standards synthesized for a quantitative LC-MS/MS investigation of cinnamoylphenethylamines in amaranth. Four cinnamoylphenethylamines (caffeoyltyramine, feruloyldopamine, sinapoyltyramine, and p-coumaroyltyramine) are reported in the Amaranthaceae for the first time; also, one rare compound, feruloyl-4-O-methyldopamine, appeared to be quite common in the genus Amaranthus. Feruloyldopamine showed moderate antifungal activity toward an isolate of Fusarium culmorum. Our LC-MS approach, in conjunction with the straightforward synthesis, provides a simple, reliable way of quantitatively investigating cinnamoylphenethylamines in plants. Concentrations of cinnamoylphenethylamines vary widely: feruloyltyramine was present in quantities of 5.26 to 114.31 microg/g and feruloyldopamine in quantities of 0.16 to 10.27 microg/g, depending on the plant sample.

Fate of benzoxazinone allelochemicals in soil after incorporation of wheat and rye sprouts.

Growing cereals (especially rye), which are incorporated into the soil to increase soil fertility or organic matter content, is a common practice in crop rotation. The additional sanitizing effect of this incorporation has often been appreciated and is said to be due to leaching of benzoxazinones and subsequent formation of benzoxazolinones. In this study wheat (Stakado) and rye (Hacada) sprouts were incorporated into soil in amounts that simulated agricultural practice. By extraction and subsequent LC-MS analysis the disappearance and appearance of benzoxazinones, benzoxazolinones, and phenoxazinones in soil were followed. In the wheat experiments 6-methoxybenzoxazolin-2-one (MBOA) was detected as the main compound. 2-Hydroxy-7-methoxy-1,4-benzoxazin-3-one (HMBOA) and 2-hydroxy-1,4-benzoxazin-3-one (HBOA) were detected as well. No phenoxazinones were detected. For the rye experiment the picture was more complex. In the first 2 days of incubation MBOA and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) were detected as the main allelochemicals along with HBOA, HMBOA, and benzoxazolin-2-one (BOA), in decreasing order. Later in the incubation period some 2-amino-3H-phenoxazin-3-one (APO) was detected and the amount of HBOA increased considerably and decreased again. The profiling of the benzoxazinone metabolites and their derivates in soil was dynamic and time-dependent. The highest concentrations of most of the compounds were seen at day 1 after incorporation. A maximum concentration was reached at day 4 for a few of the compounds. This study is the first of its kind that shows the dynamic pattern of biologically active benzoxazinone derivates in soil after incorporation of wheat and rye sprouts. Methods for organic synthesis of HBOA and HMBOA were developed as part of the study.

Elucidating the transformation pattern of the cereal allelochemical 6-methoxy-2-benzoxazolinone (MBOA) and the trideuteriomethoxy analogue [D3]-MBOA in soil.

To deduce the structure of the large array of compounds arising from the transformation pathway of 6-methoxybenzoxazolin-2-one (MBOA), the combination of isotopic substitution and liquid chromatography analysis with mass spectrometry detection was used as a powerful tool. MBOA is formed in soil when the cereal allelochemical 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) is exuded from plant material to soil. Degradation experiments were performed in concentrations of 400 microg of benzoxazolinone/g of soil for MBOA and its isotopomer 6-trideuteriomethoxybenzoxazolin-2-one ([D3]-MBOA). Previously identified metabolites 2-amino-7-methoxyphenoxazin-3-one (AMPO) and 2-acetylamino-7-methoxyphenoxazin-3-one (AAMPO) were detected. Furthermore, several novel compounds were detected and provisionally characterized. The environmental impact of these compounds and their long-range effects are yet to be discovered. This is imperative due to the enhanced interest in exploiting the allelopathic properties of cereals as a means of reducing the use of synthetic pesticides.

Andrastin A and barceloneic acid metabolites, protein farnesyl transferase inhibitors from Penicillium albocoremium: chemotaxonomic significance and pathological implications.

A survey of Penicillium albocoremium was undertaken to identify potential taxonomic metabolite markers. One major and four minor metabolites were consistently produced by the 19 strains surveyed on three different media. Following purification and spectral studies, the metabolites were identified as the known protein farnesyl transferase inhibitors andrastin A (1) and barceloneic acid A (2) along with barceloneic acid B (3), barceloneic lactone (4), and methyl barceloneate (5). These compounds are significant taxonomic markers for P. albocoremium; moreover this is the first report of a methyl ester of a barceloneic acid being produced as a secondary metabolite. Tissue extracts created following pathogenicity trials involving P. albocoremium and Allium cepa confirmed the production of these five metabolites in planta. Barceloneic acid B was found to be biologically active against a P388 murine leukemia cell line.

Substrate specificity of the bovine serum amine oxidase and in situ characterisation of aminoaldehydes by NMR spectroscopy.

The oxidation of spermidine or homospermidine with bovine serum amine oxidase (BSAO) was monitored in situ, using proton nuclear magnetic resonance spectroscopy in water with 10% D(2)O. NMR assignments were performed by spin decoupling and COSY spectra or by comparison with data from synthetic aminoaldehydes. The results represent the first in situ characterisation of the highly reactive aminoaldehydes and showed oxidation at the N(1) amino group of spermidine and homospermidine. Comparison of homospermidine with a variety of substrates revealed that among straight chain di- and polyamines both an aminopropyl group and two primary amino groups separated by seven (norspermidine) or eight (spermidine) carbon atoms were required for optimal substrate ability. However, highest activity was seen with the substrate N-(4-aminobutyl)hexahydropyrimidine, showing that the substrate channel of BSAO has a dual substrate preference, with moderately bulky substituents at the distal end of a diamine contributing equally well as an alkyl amino group. Cytotoxic investigations of a variety of substrates for BSAO, confirmed previous results, that cytotoxicity is primarily linked to polyamines encompassing the aminopropyl moiety. No acrolein was observed at any time during the oxidation showing that it reacts very fast with available amino groups forming a variety of derivatives.

Transformation products of 2-benzoxazolinone (BOA) in soil.

Three degradation experiments were performed to examine the formation of transformation products from 2-benzoxazolinone (BOA) in different soil types and concentrations. In two experiments using BOA in low concentration (400 microgkg(-1)) only one unidentified transformation product was found, whereas in the degradation experiment in high concentration (400 mgkg(-1)) several metabolites occurred. Two of these metabolites, 2-amino-(3H)-phenoxazin-3-one (APO); and 2-acetylamino-(3H)-phenoxazin-3-one (AAPO) were synthesized to prove their identity. This is the first time that the successive formation of these types of compounds from BOA is shown in soil. A number of other APO related transformation products were detected and provisionally characterized. The formation of APO, which is a much more biologically active compound than BOA, and the concurrent formation of a number of other APO-related metabolites in soil underline the importance of performing transformation studies as part of the evaluation of the effect of allelochemicals on weeds and soil-borne diseases.

Bioactive cyclic peptides from the psychrotolerant fungus Penicillium algidum.

A new cyclic nitropeptide, psychrophilin D (1), together with two known cyclic peptides, cycloaspeptide A (2) and cycloaspeptide D (3), were isolated from the psychrotolerant fungus Penicillium algidum using C18 flash chromatography, LH-20 Sephadex and preparative HPLC. The structure of psychrophilin D (1) was derived from mass spectrometric information, 1D and 2D NMR spectra and Marfey's method. The compounds were tested in antimicrobial, antiviral, anticancer and antiplasmodial assays. Psychrophilin D (1) exhibited a moderate activity (ID50 10.1 microg/ml) in the P388 murine leukaemia cell assay. Cycloaspeptide A (2) and D (3) exhibited moderate activity (IC50 3.5 and 4.7 microg/ml, respectively) against Plasmodium falciparum.

Communesins G and H, new alkaloids from the psychrotolerant fungus Penicillium rivulum.

Communesins G (1) and H (2), two new alkaloids, have been isolated from the psychrotolerant, new species Penicillium rivulum Frisvad. The compounds were isolated by high-speed countercurrent chromatography and preparative HPLC using UV-guided fractionation. The structures were determined from 1D and 2D NMR techniques and HRESIMS. In contrast to all other known communesins, 1 and 2 were found inactive in antimicrobial, antiviral, and anticancer assays.

Karnatakafurans A and B: two dibenzofurans isolated from the Fungus Aspergillus karnatakaensis.

Karnatakafurans A (1) and B (2), two novel dibenzofurans, have been isolated from the Specie Novum Aspergillus karnatakaensis Frisvad. The compounds were the major secondary metabolites and were isolated through UV-guided fractionation of the organic extract. The structures were elucidated by spectroscopic methods including MS and NMR. The compounds were tested for antimicrobial and antimalarial activity and proved to be moderately active against Plasmodium falciparum.

Psychrophilin B and C: cyclic nitropeptides from the psychrotolerant fungus Penicillium rivulum.

Psychrophilins B (1) and C (2), two new cyclic nitropeptides, have been isolated from the psychrotolerant, new species Penicillium rivulum Frisvad. The nitropeptides were isolated by high-speed countercurrent chromatography (HSCCC) and HPLC using UV-guided fractionation of the organic extract.

Psychrophilin A and cycloaspeptide D, novel cyclic peptides from the psychrotolerant fungus Penicillium ribeum.

Two fungal metabolites, psychrophilin A (1) and cycloaspeptide D (2), together with the known cycloaspeptide A (3) were isolated from the psychrotolerant fungus Penicillium ribeum using high-speed countercurrent chromatography (HSCCC) and preparative HPLC. The structures were determined from 1D and 2D NMR techniques, HREIMS, tandem mass spectrometry (ESMS/MS), and X-ray crystallography. The amino acid residues of psychrophilin A (1) and cycloaspeptide D (2) were all found to possess the l configuration by Marfey's method. Psychrophilin A (1) is the first natural cyclic peptide containing a nitro group instead of an amino group.

Surface motility in Pseudomonas sp. DSS73 is required for efficient biological containment of the root-pathogenic microfungi Rhizoctonia solani and Pythium ultimum.

Pseudomonas sp. DSS73 was isolated from the rhizoplane of sugar beet seedlings. This strain exhibits antagonism towards the root-pathogenic microfungi Pythium ultimum and Rhizoctonia solani. Production of the cyclic lipopeptide amphisin in combination with expression of flagella enables the growing bacterial culture to move readily over the surface of laboratory media. Amphisin is a new member of a group of dual-functioning compounds such as tensin, viscosin and viscosinamid that display both biosurfactant and antifungal properties. The ability of DSS73 to efficiently contain root-pathogenic microfungi is shown to arise from amphisin-dependent surface translocation and growth by which the bacterium can lay siege to the fungi. The synergistic effects of surface motility and synthesis of a battery of antifungal compounds efficiently contain and terminate growth of the microfungi.

Lipopeptide production in Pseudomonas sp. strain DSS73 is regulated by components of sugar beet seed exudate via the Gac two-component regulatory system.

Pseudomonas sp. strain DSS73 isolated from the sugar beet rhizosphere produces the cyclic lipopeptide amphisin, which inhibits the growth of plant-pathogenic fungi. By Tn5::luxAB mutagenesis, we obtained two nonproducing mutant strains, DSS73-15C2 and DSS73-12H8. The gene interrupted by the transposon in strain DSS73-15C2 (amsY) encoded a protein with homology to peptide synthetases that was designated amphisin synthetase. DSS73-12H8 carried the transposon in a regulatory gene encoding a protein with homology to the sensor kinase GacS. Growth of strain DSS73-15C2 (amsY) was impaired during the transition to stationary phase in a minimal medium amended with an exudate of sugar beet seeds. This growth phenotype could be complemented by purified amphisin. Seed exudate further induced expression of bioluminescence from the amsY::luxAB reporter during the transition to stationary phase. This agreed with an increase in amphisin production by the DSS73 wild-type strain during early stationary phase. Amphisin synthesis in DSS73 was strictly dependent on GacS, and even induction by seed exudate depended on a functional gacS locus. Hence, a signal triggering the GacS/GacA two-component system appeared to be present in the seed exudate.

Bioactive metabolites from a marine-derived strain of the fungus Emericella variecolor.

From a marine-derived strain of the fungus Emericella variecolor, varitriol (1), varioxirane (2), dihydroterrein (3), and varixanthone (4), besides the known mold metabolites ergosterol, terrein, shamixanthone, and tajixanthone hydrate, were identified. The chemical structures of 1-4 were established by means of spectroscopic techniques and some chemical transformations. In the NCI's 60-cell panel, varitriol (1) displayed increased potency toward selected renal, CNS, and breast cancer cell lines. Varixanthone (4) showed antimicrobial activity.

How Delisea pulchra furanones affect quorum sensing and swarming motility in Serratia liquefaciens MG1.

Halogenated furanones produced by the benthic marine macroalga Delisea pulchra inhibit swarming motility of Serratia liquefaciens MG1. This study demonstrates that exogenously added furanones control transcription of the quorum sensing regulated gene swrA in competition with the cognate signal molecule N:-butanoyl-L-homoserine lactone. This in turn results in reduced production of the surface-active compound serrawettin W2, which is crucial for surface translocation of the differentiated swarm cells. It is demonstrated that furanones interfere with interspecies communication during swarming of mixed cultures and that the mode of interference in quorum-sensing control and interspecies communication is not through inhibition of autoinducer synthesis.