Infection of CCB preserved and leached wood specimens with wood decay fungi

Les, zaščiten s pripravki CCB, je odporen proti trohnjenju. Vendar v zadnjih letih opažamo, da se na lesu, impregniranem s CCB, pojavljajo okužbe z glivami, tolerantnimi na Cu. V raziskavi smo opazovali preraščanje in penetracijo hif na zaščitenih vzorcih, izpostavljenim glivam razkrojevalkam, in osvetlili vpliv izpiranja na kolonizacijo. Vzorce smo izdelali iz beljave smrekovine (Picea abies) in jih impregnirali s 5 % raztopino CCB v skladu s standardom SIST EN 113. Del kondicioniranih vzorcev smo izpirali po standardu SIST EN 84. V tretjino izpranih in neizpranih vzorcev smo vzdolžno zvrtali luknjo in vanjo vstavili palčko (r = 1,5 mm, l = 25 mm). Nato smo odprtino zatesnili z epoksidnim premazom. Sterilizirane impregnirane in neimpregnirane vzorce smo izpostavili dvema na baker tolerantnima sevoma (Antrodia vaillantii in Leucogyrophana pinastri) in dvema na baker občutljivima izolatoma (Poria monticola, Gloeophyllum trabeum). Po izpostavitvi smo iz vzorcev previdno odstranili palčko in jo postavili na sterilno hranilno gojišče, kjer smo dva tedna opazovali prisotnost hif. Stopnjo kolonizacije smo ovrednotili tudi z merjenjem CO2. Po 16 tednih izpostavitve smo ugotovili še izgubo mase izpostavljenih vzorcev. Neimpregnirane vzorce so najhitreje prerasle hife glive G. trabeum. Po drugi strani pa pri vzorcih, impregniranih s CCB, na palčkah tudi po 12 tednih izpostavitve nismo zasledili prisotnosti hif. Prodiranje hif pri izpranih impregniranih vzorcih je bilo bistveno hitrejše. Menimo, da je razlog za intenzivnejšo kolonizacijo izpranih vzorcev, impregniranih s CCB, izprani bor, ki v nižjih koncentracijah ni zaviral preraščanja micelija.CCB treated wood is generally resistant to all wood decay fungi. However, like at CCA impregnated wood, susceptibility of CCB treated wood to copper tolerant fungi have been observed. It was investigated whether the hyphae of brown rot fungi could overgrow on and penetrate into the wood samples. Samples made of Norway spruce (Picea abies) were impregnated with 5 % CCB solution according to the EN 113 procedure. After conditioning, part of the samples was leached according to the EN 84 method. A small stick of unimpregnated wood (r = 1.5 mm, l = 25 mm) was inserted into a hole, bored in the center of the sample, and then sealed with epoxy coating. Sterilized, leached and non-leached impregnated and unimpregnated specimens were exposed to two copper-tolerant (Antrodia vaillantii, Leucogyrophana pinastri) and two copper sensitive (Poria monticola, Gloeophyllum trabeum) brown rot fungal strains. After exposure, the inserted wood pieces were removed from the specimens and put onto nutrient medium in petri dishes. Growth of the hyphae from those wood pieces was then visually determined. Rate of colonization by the fungi was determined by measurement of CO2. Mass losses after 16 weeks of exposure were also determined. The fastest colonization of the unimpregnated specimens was by G. trabeum. On the other hand, no fungal growth could be detected on non-leached CCB impregnated specimens even after 12 weeks of exposure. However, significantly more intense colonization by the copper tolerant fungi was detected on the leached CCB treated samples. We concluded that the reason for observed higher susceptibility originates in leached boron, which did not influence, in lower concentrations, fungal growth

Primjena lakaze za dogradnju lignoceluloznih vlakanaca

Laccases have the ability to oxidize both phenolic and trough mediators non-phenolic lignin related compounds. When reacting on lignin, they can display both ligninolytic and polymerizing (cross-inking) abilities, which makes them very useful for their application in industries based on lignocellulose material. Most of the published papers and applications of laccase and laccase-mediator systems on lignocellulose material relate to the pulp, paper and textile industry. Recent research has been done in terms of laccase assisted biografting of phenols and other compounds on wood surface and use of laccase for adhesion enhancement in fiberboard production. They can be introduced to wood technology as environmentally friendly enzymes. The paper reviews the application of laccases in industries based on lignocellulose material and discusses the future outlook and development in the above mentioned fields.Enzimi lakaze imaju sposobnost oksidacije fenolnih spojeva uz pomoć medijatora i nefenolnih spojeva lignina. Kada reagiraju na lignin, mogu pokazati i ligninolitičke i polimerizacijske (unakrsno povezujuće) sposobnosti, što ih čini vrlo korisnima za primjenu u industriji utemeljenoj na lignoceluloznim materijalima. Većina objavljenih radova i primjena enzima lakaze i posredničkih lakaza-sustava na lignoceluloznim materijalima odnose se na celulozu, papir i proizvode tekstilne industrije. Nedavno su provedena istraživanja o kalemljenju fenola i drugih spojeva uz pomoć lakaza na površinu drva i o primjeni lakaza za poboljšanje adhezije u proizvodnji ploča vlaknatica. Lakaze se mogu upotrijebiti u drvnoj tehnologiji kao ekološki prihvatljivi enzimi. U radu se analizira primjena enzima lakaze u industriji utemeljenoj na lignoceluloznim materijalima i razmatraju se buduće perspektive i razvoj na spomenutim područjima

Copper translocation from preserved wood exposed to wood decay fungi

Copper tolerance by wood decay fungi is one of the most important problems in the field of wood preservation. These fungi are potential danger for preserved wood in use, wood with expected lifetime of 30 years. Although, the nature of the fungal tolerance is still not completely understood. The resistance of some species of wood decay fungi to copper has been connected to their production of copious amounts of oxalic acid. However, oxalic acid production is not the only factor responsible for this phenomenon. Laboratory experiments showed that one other important mechanism is active copper transport of copper tolerant fungi and diffusion of copper by intolerant ones

Copper translocation from preserved wood exposed to wood decay fungi

Na področju zaščite lesa se v zadnjem času pojavljajo na baker odporni sevi gliv, kar v praksi predstavlja velik problem. Tolerantne glive ogrožajo zaščiten les v uporabi z običajno trajnostjo nad 30 let, saj les okužen s tolerantnimi sevi gliv lahko propade že v nekaj letih. Mehanizmi tolerantnosti še niso povsem pojasneni. Velik pomen se pripisuje oksalni kislini, ki jo intenzivno tvorijo tolerantne glive. Z laboratorijskimi poskusismo ugotovili, da je poleg tega mehanizma pomemben tudi aktivni transport bakra v micelij gliv. Pri glivah, ki ne izločajo oksalne kisline, jetranslokacija bakra povzročena z difuzijoCopper tolerance by wood decay fungi is one of the most important problems in the field of wood preservation. These fungi are potential danger for preserved wood in use, wood with expected lifetime of 30 years. Although, the nature of the fungal tolerance is still not completely understood. The resistance of some species of wood decay fungi to copper has been connected to their production of copious amounts of oxalic acid. However, oxalic acid production is not the only factor responsible for this phenomenon. Laboratory experiments showed that one other important mechanism is active copper transport of copper tolerant fungi and diffusion of copper by intolerant one

Screening of selected wood-damaging fungi for the HIV-1 reverse transcriptase inhibitors

Iz 57 vrst lesnih gliv sta bili pripravljeni dve seriji izvlečkov. V prvi so bili izvlečki, pripravljeni z metanolom, v drugi pa z diklormetanom. Preizkušenih je bilo 63 vzorcev, saj so bile nekatere vrste zastopane z večjim številom izolatov. Izvlečkom smo in vitro preizkusili inhibitorno aktivnost na HIV-1 reverzno transkriptazo s pomočjo neradioaktivne metode. 13 metanolnih izvlečkov je inhibiralo encim več kot 40-odstotno, med njimi sta dva inhibirala encim več kot 80-odstotno. Najbolj učinkovita sta bila izvlečka gliv Laetiporus sulphuerus in Poria monticola, sledita jim izvlečka vrst Poria vaillanti in Chondrostereum purpureum. V nadaljevanju raziskave smo ugotavljali inhibitorno aktivnost različitih izolatov glive Laetiporus sulphureus. Najbolj aktivne izvlečke smo frakcionirali s pomočjo preparativne tekočinske kromatografije. Domnevamo, da bi bila lahko v najbolj aktivni frakciji prisotna spojina ali spojine, ki so kisle narave in imajo v strukturi amino skupino.Extracts obtained by using methanol and dichloromethane from 57 species of wood damaging fungi were investigated for their ability to inhibit HIV-1 reverse transcriptase activity in vitro using non-radioactive assay. Sixty tree samples were tested all together; some species were represented by more than one isolate. Thirteen methanol extracts exhibited more than 40% inhibition and two among them inhibited the enzyme more than 80%. All extracts obtained with dichloromethane were inferior to methanolic extracts in their inhibitory activity. The most active fungal species discovered in the first screening were Laetiporus sulphureus and Poria monticola, followed by Poria vaillanti and Chondrostereum purpureum. In the second screening, Laetiporus sulphureus was selected for detailed examination and different isolates were tested. Preliminary findings confirmed a presence of acidic compound with amino group in the most active fraction

Screening of selected wood-damaging fungi for the HIV-1 reverse transcriptase inhibitors

Iz 57 vrst lesnih gliv sta bili pripravljeni dve seriji izvlečkov. V prvi so bili izvlečki, pripravljeni z metanolom, v drugi pa z diklormetanom. Preizkušenih je bilo 63 vzorcev, saj so bile nekatere vrste zastopane z večjim številom izolatov. Izvlečkom smo in vitro preizkusili inhibitorno aktivnost na HIV-1 reverzno transkriptazo s pomočjo neradioaktivne metode. 13 metanolnih izvlečkov je inhibiralo encim več kot 40-odstotno, med njimi sta dva inhibirala encim več kot 80-odstotno. Najbolj učinkovita sta bila izvlečka gliv Laetiporus sulphuerus in Poria monticola, sledita jim izvlečka vrst Poria vaillanti in Chondrostereum purpureum. V nadaljevanju raziskave smo ugotavljali inhibitorno aktivnost različitih izolatov glive Laetiporus sulphureus. Najbolj aktivne izvlečke smo frakcionirali s pomočjo preparativne tekočinske kromatografije. Domnevamo, da bi bila lahko v najbolj aktivni frakciji prisotna spojina ali spojine, ki so kisle narave in imajo v strukturi amino skupino.Extracts obtained by using methanol and dichloromethane from 57 species of wood damaging fungi were investigated for their ability to inhibit HIV-1 reverse transcriptase activity in vitro using non-radioactive assay. Sixty tree samples were tested all together; some species were represented by more than one isolate. Thirteen methanol extracts exhibited more than 40% inhibition and two among them inhibited the enzyme more than 80%. All extracts obtained with dichloromethane were inferior to methanolic extracts in their inhibitory activity. The most active fungal species discovered in the first screening were Laetiporus sulphureus and Poria monticola, followed by Poria vaillanti and Chondrostereum purpureum. In the second screening, Laetiporus sulphureus was selected for detailed examination and different isolates were tested. Preliminary findings confirmed a presence of acidic compound with amino group in the most active fraction

Synthesis and Characterization of Fatty Acid Copper(II) Carboxylates with N,N-Diethylnicotinamide

A series of new fatty acid copper(II) carboxylates of the composition [(Cu2(O2CCnH2n+1)4(Et2nia)2)] (Et2nia = N,N-diethylnicotinamide; n = 6 to 11) were synthesized, characterized and tested for fungicidal activity. The compounds were synthesized and crystallized from aqueous solution only because their solubility in organic solvents is too high. Dimeric structure for ali compounds was proposed (μeff at room temperature = 1.43-1.48 BM; UV-Vis λmax at 350-400 nm; IR, Δν(COO-) = 185-199 cm-1). A binuclear paddlewheel cage structure was found for the compound [(Cu2(O2CC7H15)4(Et2nia)2)] by X-ray diffraction. Screening for fungicidal activity against the woodrotting fungi Trametes versicolor and Antrodia vaillantii shows that the compounds dissolved in DMSO stop mycelium growth completely at a concentration of 1.0 × 10-3 mol L-1. Some of them show strong activity also in more diluted Solutions; however, stronger retardation for Antrodia vaillantii was noticed for all substances