Diversity and taxonomy of Chaetomium and chaetomium-like fungi from indoor environments

During a study of indoor fungi, 145 isolates belonging to Chaetomiaceae were cultured from air, swab and dust samples from 19 countries. Based on the phylogenetic analyses of DNA-directed RNA polymerase II second largest subunit (rpb2), β-tubulin (tub2), ITS and 28S large subunit (LSU) nrDNA sequences, together with morphological comparisons with related genera and species, 30 indoor taxa are recognised, of which 22 represent known species, seven are described as new, and one remains to be identified to species level. In our collection, 69 % of the indoor isolates with six species cluster with members of the Chaetomium globosum species complex, representing Chaetomium sensu stricto. The other indoor species fall into nine lineages that are separated from each other with several known chaetomiaceous genera occurring among them. No generic names are available for five of those lineages, and the following new genera are introduced here: Amesia with three indoor species, Arcopilus with one indoor species, Collariella with four indoor species, Dichotomopilus with seven indoor species and Ovatospora with two indoor species. The generic concept of Botryotrichum is expanded to include Emilmuelleria and the chaetomium-like species B. muromum (= Ch. murorum) in which two indoor species are included. The generic concept of Subramaniula is expanded to include several chaetomium-like taxa as well as one indoor species. Humicola is recognised as a distinct genus including two indoor taxa. According to this study, Ch. globosum is the most abundant Chaetomiaceae indoor species (74/145), followed by Ch. cochliodes (17/145), Ch. elatum (6/145) and B. piluliferum (5/145). The morphological diversity of indoor Chaetomiaceae as well as the morphological characteristics of the new genera are described and illustrated. This taxonomic study redefines the generic concept of Chaetomium and provides new insight into the phylogenetic relationships among different genera within Chaetomiaceae

Infection by a foliar endophyte elicits novel arabidopside-based plant defence reactions in its host, Cirsium arvense

Endophytic fungi live asymptomatically within plants. They are usually regarded as non-pathogenic or even mutualistic, but whether plants respond antagonistically to their presence remains unclear, particularly in the little-studied associations between endophytes and nong-raminoid herbaceous plants. We investigated the effects of the endophyte Chaetomium cochlioides on leaf chemistry in Cirsium arvense. Plants were sprayed with spores; leaf material from both subsequent new growth and the sprayed leaves was analysed 2 wk later. Infection frequency was 91% and63% for sprayed and new growth, respectively, indicating that C. cochlioides rapidly infects new foliage. Metabolomic analyses revealed marked changes in leaf chemistry with infection, especially in new growth. Changes in several novel oxylipin metabolites were detected, including arabi-dopsides reported here for the first time in a plant species other than Arabidopsis thaliana,and a jasmonate-containing galactolipid. The production of these metabolites in response to endophyte presence, particularly in newly infected foliage, suggests that endophytes elicit similar chemical responses in plants to those usually produced following wounding, herbivory and pathogen invasion. Whether en-dophytes benefit their hosts may depend on a complex series of chemically mediated interactions between the plant, the endophyte, other microbial colonists and natural enemies

Kajian Awal terhadap Sistem Pemilihan Somaklon CUi Yang Resistans kepada Colletotrichum capsici (Syd.) Butler & Bisby

Toxin treatment from the anthracnose pathogen, Colletotrichum capsici on chilli tissue culture was utilised as the selection mechanism for variants which are resistant to this pathogen. The crude toxin preparation was sterilised and then added to the MS medium at the concentration of 0, 10, 20, 30 or 40% (v/v). At concentrations higher than 20 %, the toxin prevented the formation of calli from hypocotyl explants, and at 10% and 20 %, the formation of calli was strongly inhibited. The calli which survived the toxin treatment did not regenerate. Conversely, calli which were cultured on MS medium suplemented with VB juice or on the control MS medium, were able to regenerate at 37.6% and 62.7%, respectively. Induction of resistant variants was attempted by inoculating the calli with the konidia from the anthracnose pathogen. The antibiotic which had been extracted from an antagonistic fungus, Chaetomium trilaterale, was added to the MS medium to limit the spread of the pathogen to the medium from the chilli calli. From the antibiotic assay, the developement of the pathogen was dependent on the antibiotic concentration used in the media. The minimum antibiotic concentration which successfully prevented the growth of the fungal pathogen was 100 mg/ml. At that concentration, the fungus was only observed on the calli but not on the medium. However, the calli turned brown after 2 weeks of inoculation. In addition, the calli that survived became compacted and failed to regenerate

Root rot as a cause of red clover decline in leys in Finland

vokKirjasto Aj-kJuurilaho puna-apilan hävittäjänä Suomen niittonurmiss

Új sztereoszelektív biokatalitikus folyamatok és biokatalizátorok = Novel stereoselective biocatalytical processes and biocatalysts

Napjainkban az egyik legnagyobb kémiai kihívás a biológiailag aktív anyagok gazdaságos szintézise. Egyre nagyobb az igény a sztereoizomerek - pl. a királis anyagok adott enantiomerjének - tiszta formában történő előállítására. Ezzel kapcsolatban több, egymással összefüggő területen folytattuk tevékenységünket. Új, magas enantiomer szelektivitású biotranszformációkat elsősorban lipáz-katalizált acilezési folyamatokkal végeztünk [13 publ.]. Az akirális kiindulási anyagból elvileg akár teljes mértékben enantiomer tiszta királis termékeket szolgáltató aszimmetrikus szintéziseket prokirális ketonok mikrobiális redukciója és prokirális illetve mezo vegyületek lipáz-katalizált acilezési reakcióival végeztünk [6 publ.]. A biotranszformációk során fontos szerepet játszik a biokatalizátor szelektivitása és stabilitása. Ez több úton is javítható: új enzimek keresésével [2 publ], vagy a már ismert enzimek tulajdonság-javulást eredményező rögzítésével [3 publ.]. Az enzimkatalizált folyamatok molekuláris szintű megismerése visszahat a szintetikus módszerekre, mivel így a biokatalítikus folyamatok fejlesztése mindinkább célzottá és tervezhetővé válik. Ezen ismeretek bővüléséhez az ammónia liáz (PAL/HAL/TAL) enzimek működésének molekuláris szintű tanulmányozásával járultunk hozzá [7 publ.]. Az enzimeken belüli számítások alkalmasnak bizonyultak lipázok sztereoszelektivitásának értelmezésére és így abszolút konfiguráció hozzárendelésre is [2 publ]. | In our days the economical synthesis of the biologically active compounds is one of the major challenges of chemistry. There is an ever increasing demand for syntheses of stereoisomers, most prominently a given enantiomer of a chiral compound. Our activities were related to this area. Novel enantiomer selective biotransformations were performed principally by lipase-catalyzed acylations [13 publ.]. Asymmetric syntheses which can provide theoretically full conversion of an achiral substrate to an enantiomerically pure chiral product were performed by microbial reductions of prochiral ketones or lipase-catalyzed acylation reactions of prochiral or meso compounds [6 publ.]. The selectivity and stability of the biocatalyst plays an essential role in biotransformations. These properties can be enhanced by screens for novel enzymes [2 publ] or by novel beneficial immobilization methods of known enzymes [3 publ.]. Elucidation of the enzyme-catalyzed processes at molecular level can have a positive feedback on the synthetic methods because designing of biocatalytic reactions can became more and more targeted and plannable. Pieces were adde to this puzzle by our studies of the reactions of ammonia-lyases (PAL/HAL/TAL) at molecular level [7 publ.]. The calculations within enzymes proved to be applicable for explanation of the stereoselectivities of lipases and thus absolute configuration assignment of the products [2 publ]