Screening of the genus Cercospora for secondary metabolites

Screening of 61 species of Cercospora grown on a potato-agar medium showed the presence of the phytotoxin cercosporin in 24 of them, and of dothistromin in 8. Some strains of C. beticola produce a yellow phytotoxin (CBT). The new metabolites cercosporin esters, ligustrone A, B, C, taiwapyrone, 3-methoxy-2,5,7-trihydroxy-1,4-naphthaquinone, cis-4,6-dihydroxymellein and ( ? )-11-acetyldehydrocurvularin were isolated besides the known cynodontin, ( ? )-dehydrocurvularin, (+ )-mellein and cis-3S,4S-4-hydroxymellein.     

Distribution of the genus Leptospira in soil and water

The distribution of the aerobic spirochetes Leptospira in surface waters, soil, and aquatic animals was investigated. Isolates from water and soil exhibited physiological characteristics common to members of the "biflexa complex," none were capable of infecting experimental animals, and leptospires could not be isolated from the eight genera of aquatic animals examined. The isolation frequencies from surface waters were: stream, 100%; lake, 65%; spring, 28%; bog lake, 5%; and marsh, 0%. With the exception of the stream, more isolations were obtained from the soil adjacent to the water than from the water. Leptospires were most frequently associated with soils of high moisture and organic matter content.     

Secondary metabolites in in vitro cultured plants of the genus Drosera

Extracts from plantlets of different species of the genus Drosera, grown as in vitro cultures, were evaluated for the level of phenolic secondary metabolites from the group of naphthoquinones and flavonols. The profiles of natural products in the extracts obtained from different species were monitored by HPLC with UV detection at 260 and 330 nm. On the basis of the data obtained, Drosera binata, the species with the highest amount of plumbagin, was selected for further studies. The most effective method of extraction of quinones was established and the composition of phenolic secondary metabolites in the tissues was determined. For the identification of phenolic compounds, HPLC-UV and HPLC-ESI/MS were applied.     

Molecular phylogenetic analyses reveal three new Ceratocystis species and provide evidence for geographic differentiation of the genus in Africa

The emergence of wattle wilt disease on non-native Acacia mearnsii trees in Africa, caused by the indigenous fungus Ceratocystis albifundus, has highlighted a need to better understand the diversity, ecology and distribution of Ceratocystis species in natural African environments. In this study we applied phylogenetic inference to identify and characterize isolates of Ceratocystis collected in a natural savanna ecosystem in South Africa. Three new species were recognized and are described as C. cryptoformis sp. nov. in the C. moniliformis complex, as well as C. thulamelensis sp. nov. and C. zambeziensis sp. nov., both residing in the C. fimbriata complex. Incorporating the new species into global phylogenies of Ceratocystis provided insights into the patterns of evolution and biogeography of this group of fungi. Notably, the African continent was identified as an important centre of diversification of Ceratocystis spp., from which several lineages of these fungi were shown to have radiated.     

Involvement of individual hippocampal signaling protein levels in spatial memory formation is strain-dependent

Although a series of signaling cascades involved in spatial memory have been identified, their link to spatial memory and strain-dependent expression has not been reported so far. Hippocampal levels of the abovementioned signaling proteins were determined in laboratory inbred strain C57BL/6J, the wild-derived inbred strain PWD/PhJ and the wild caught mouse Apodemus sylvaticus (AS) by immunoblotting. The resulting hippocampal protein levels were correlated with results from MWM. Hippocampal signaling protein (hSP) levels were tested also in yoked controls. Within-strain comparison between trained and yoked controls revealed significant differences between levels of Phospho-CaMKII (alpha), Phospho-CREB, Egr-1, c-Src, Phospho-ERK5, Phospho-MEK5 and NOS1 in all of the three strains tested. In addition, the three strains revealed different involvement of individual hSP levels clearly indicating that individual mouse strains were linked to individual hSPs in spatial memory. Phospho-ERK5 levels were not detectable in hippocampi of yoked controls of each strain. We learn from this study that a series of hSPs are associated with spatial memory and that different hSPs are linked to spatial memory in different strains that show different outcome in the MWM. Even correlational patterns in the individual hSPs differed between mouse strains. This is of importance for the interpretation of previous studies on the abovementioned signaling cascades as well as for the design of future studies on these hippocampal proteins. It is intriguing that individual mouse strains, laboratory or wild caught, may use different signaling pathways for spatial memory in the Morris water maze.     

Envelope formation and structure in the Euglenoid genus Trachelomonas

Ultrastructural details of envelope formation are described comparatively for several species of the genus Trachelomonas. The first-formed envelope component in T. oblonga var. punctata Prings. is an external “skin”. Next, a fibrillar layer is produced between the skin and the cell surface. Ferric hydroxide and manganese compounds are precipitated on this inner layer to form a thick envelope, species-specific in size, shape, ornamentation and collar characteristics. The original skin is then lost.

A similar sequence of events occurs during envelope formation in other species, but differences exist in the details of the process and in the texture and complexity of construction of the mature envelopes. T. volvocina Ehrenb. has a fibrillar inner layer and granular precipitation, but produces a complex three-layered envelope with a honeycombed central layer. This is compared with the superficially similar three-layered envelope of an unnamed species from a wild collection, and subtle differences in ultrastructural patterning are discussed. T. pertyi Prings. forms a two-layered spiny envelope, less highly organised than that of T. volvocina. The spiny and porous envelopes of T. hispida (Perty) Stein em. Defl., T. echinata Singh and T. lefevrei Defl. are quite different in texture, being composed of flaky material woven into a spongy matrix. The presence of large amounts of iron in the mature envelopes of all the species under study was confirmed by microanalysis in the electron microscope using X-ray spectroscopy.

Details of envelope ultrastructure are discussed in relation to taxonomy, cell metabolism, the problem of why Trachelomonas cells form envelopes when those of other euglenoid genera do not, and the problem of cell control of species-specificity of envelope characters. Electron microscopy has added considerably to our knowledge of the structural details of trachelomonad envelope formation, but it has been less successful in helping to elucidate some of the enigmas associated with this phenomenon.     

Urinary profiles of volatile and acid metabolites in germfree and conventional rats

Qualitative and quantitative differences in the urinary excretion of volatile and acidic metabolites in germfree and conventional rats were examined by capillary gas chromatography and gas chromatography/mass spectrometry. A number of carbonyl compounds, including several short-chain aliphatic ketones and acetophenone, were higher in the conventional urines, while many heterocyclic compounds (furan derivatives, benzothiazole and others) were lower. Both qualitative and quantitative differences were observed in the urinary excretion of acidic metabolites. Three meta-hydroxy phenolic acids appeared only in the conventional rat urines, while levels of many other aromatic and aliphatic acids were also higher.     

Distribution and conservation of mobile elements in the genus Drosophila

Essentially nothing is known of the origin, mode of transmission, and evolution of mobile elements within the genus Drosophila. To better understand the evolutionary history of these mobile elements, we examined the distribution and conservation of homologues to the P, I, gypsy, copia, and F elements in 34 Drosophila species from three subgenera. Probes specific for each element were prepared from D. melanogaster and hybridized to genomic DNA. Filters were washed under conditions of increasing stringency to estimate the similarity between D. melanogaster sequences and their homologues in other species. The I element homologues show the most limited distribution of all elements tested, being restricted to the melanogaster species group. The P elements are found in many members of the subgenus Sophophora but, with the notable exception of D. nasuta, are not found in the other two subgenera. Copia-, gypsy-, and F-element homologues are widespread in the genus, but their similarity to the D. melanogaster probe differs markedly between species. The distribution of copia and P elements and the conservation of the gypsy and P elements is inconsistent with a model that postulates a single ancient origin for each type of element followed by mating-dependent transmission. The data can be explained by horizontal transmission of mobile elements between reproductively isolated species.      

Headspace sorptive extraction and GC-TOFMS for the identification of volatile fungal metabolites

Volatiles from fungi cultivated in Petri dishes were collected by a simple headspace polydimethylsiloxane (PDMS) sorptive extraction technique (HSSE), thermally desorbed into a gas chromatographic capillary column and detected and identified by gas chromatography-time-of-flight mass spectrometry (GC-TOFMS). The method was used to compare metabolite profiles of seven species of fungi grown on two types of sterile agars - potato dextrose and Sabouraud dextrose. Three species from the genus Penicillium (P. italicum, P. camemberti, and P. roqueforti) and four outgroups, each from a different phylum (Saprolegnia sp.; Sordaria fimicola, wild-type; Coprinus cinereus; and Rhizopus stolonifer) were grown on the two types of agars and analyzed. Multivariate analysis (PCA) was used to determine whether separate classes of fungi can be distinguished from one another based on their metabolite profiles. PCA showed clear class separation between the three Penicillium samples and the outgroups. Slight differences were observed in metabolite profiles as a function of growth medium. HSSE/GC-TOFMS appears to be a relatively simple and accurate technique for classification of fungi based on their volatile metabolite profiles. The volatiles sampling technique reported here is non-destructive, so it can be applied with traditional methods for studying fungal growth and metabolism.     

The expression of the cerato-platanin gene is related to hyphal growth and chlamydospores formation in Ceratocystis platani

Cerato-platanin (CP) is a protein produced by Ceratocystis platani, the causal agent of canker stain disease of plane trees. CP is the first member of the 'cerato-platanin family', and its role as a pathogen-associated molecular pattern (PAMP), inducing defence responses both in host and nonhost plants, is established. However, the primary role of CP and its homologues in the fungal life remains unknown. In the present work, we investigated the regulation of the cp gene during the in vitro growth of C. platani in different conditions and under the effect of potential stress factors. Fungal growth and conidiogenesis were also analysed. Results showed that cp is a single-copy gene whose expression level is strictly associated with hyphal growth and with chlamydospores formation. The analysis of a 1368 bp 5'-flanking region revealed putative motifs that could be involved in the regulation of gene expression in response to stress and developmental cues. Taking into account the localization of CP in the fungal cell wall and the recently published 3D structure of the protein, our results support a role for CP in growth and developmental processes of C. platani.     

Antibacterial metabolites from Australian macrofungi from the genus Cortinarius

In this study, ethyl acetate and aqueous fractions from 117 collections of Australian macrofungi belonging to the mushroom genus Cortinarius were screened for antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Overall, the lipophilic fractions were more active than the aqueous fractions. The ethyl acetate fractions of most or all collections of 13 species, namely Cortinarius ardesiacus, C. archeri, C. austrosaginus, C. austrovenetus, C. austroviolaceus, C. coelopus, C. [Dermocybe canaria]², C. clelandii, C. [D. kula], C. memoria-annae, C. persplendidus, C. sinapicolor, C. vinosipes and forty seven collections of un-described Cortinarius species exhibited IC₅₀ values of ?0.09 mg/mL against S. aureus. In contrast, most or all collections of only four species, namely C. abnormis, C. austroalbidus, C. [D. kula], C. persplendidus, and eleven un-described Cortinarius collections exhibited similar effects against P. aeruginosa (IC₅₀ ? 0.09 mg/mL). Anthraquinonoid pigments isolated from C. basirubescens together with emodin physcion and erythrogluacin were assessed for their antimicrobial activity. The fungal octaketides austrocortilutein, austrocortirubin, torosachrysone, physcion and emodin were found to strongly inhibit the growth of S. aureus (IC₅₀ 0.7–12 μg/mL) whereas only physcion and emodin exhibited potency against P. aeruginosa (IC₅₀ 1.5 and 2.0 μg/mL, respectively).     

Distribution of hobo transposable elements in the genus Drosophila

This study describes the distribution of hobo-hybridizing sequences in the genus Drosophila. Southern blot analysis of 134 species revealed that hobo sequences are limited to the melanogaster and montium subgroups of the melanogaster-species group. Of the hobo-bearing species, only D. melanogaster and two of its sibling species, D. simulans and D. mauritiana, were found to contain potentially complete hobo elements. The distribution of hobo sequences is one of the narrowest distributions thus far described for any Drosophila transposable element.     

Cytotoxic activity and mechanism of action of metabolites from the Goniothalamus genus

The World Health Organization estimates that 4 billion people or 80 % of the population use plants for curative purposes or for their natural health benefits. Accordingly, biodiversity is an important source of active natural products especially used in traditional medicine as healers transmitted knowledge of traditional usage of medicinal plants from generation to generation whereas pharmacologically active compounds within remained obscure. The present review documents cytotoxicity and anti-cancer potential of known compounds of the Goniothalamus species from the Annonaceae family existing in tropical and subtropical Asia and being intensively used for medicinal purposes.     

Biological formation of volatile phosphorus compounds

Phosphine and phosphides are reported to occur at numerous environmental sites such as fresh and marine sediments, landfills, faecal matter, biogas digesters and soils. The concentrations are several log units lower than the time-weighted average exposure standard, i.e. in the order of ng per m3 of gas or ng per kg material. Research about the biological formation of highly reduced gaseous phosphorus compounds dates back more than a hundred years. The early reports had to deal with a lot of scepticism. Thanks to new analytical tools (gas chromatography) it has become clear, during the last decade, that phosphine is a global constituent of the atmosphere. Pure strains of micro-organisms cultivated under highly anaerobic conditions were shown to produce phosphine. Thermodynamic considerations indicate that it is very improbable that the reduction of phosphate to phosphine is endergonic. Therefore the generation of phosphine cannot be compared with sulphidogenesis and methanogenesis. There seems to be a link between the existence of highly reactive gaseous phosphorus compounds and increased levels of metal corrosion. The reactive compounds could be formed by micro-organisms or they are liberated from phosphorus-containing impurities in the iron by the action of bacterial metabolites. The biochemical pathways responsible for the production of gaseous phosphorus compounds have not been characterised yet.     

Distribution of alditols in the genus Bostrychia

Several species of the red algal genus Bostrychia were investigated for the presence of low-molecular weight carbohydrates constituting their specific assimilate pattern. All species were found to contain remarkable amounts of two hexitols, dulcitol and sorbitol. The results are discussed with emphasis on the chemotaxonomic implications.