4 research outputs found
Enzymatic component of antioxidative system in succulent plant Tacitus bellus as a response to hemibiotroph Fusarium verticillioides infection in vitro
Fungi and plants interact in different ways, creating a scale of associations. Hemibiotrophic
fungi represent the most interesting group, as they use sequential biotrophic and necrotrophic infection
strategies. The co-evolution of plant and fungal life-styles has not been well characterized.
We present changes of enzymatic component of antioxidative system in succulent plant Tacitus
bellus that specifically correspond to subsequent phases (spore germination, biotrophic phase,
and necrotrophic phase) of hemibiotroph Fusarium verticillioides infection. T. bellus response to F.
verticillioides spore germination was characterized by transient increase in catalase (CAT), but decrease
in superoxide dismutase (SOD) and peroxidase (POD) activity. During biotrophic phase of F.
verticillioides infection, when hyphae spread intercellularly in epidermal and mesophyll tissue, host
antioxidative system was suppressed. The transition from biotrophic to necrotrophic phase (inter
and intracellular colonization and sporulation) triggered the host plant cells to create a highly defensive
environment: CAT, SOD and POD activities were significantly stimulated, slowing, or even
currently arresting, colonization of T. bellus mesophyll cells. CAT, showing the most pronounced
activity increase, could be suggested as the main enzyme responsible for slowing the progression
of necrotrophic phase of F. verticillioides growth. However, contrary to host CAT and SOD which
isoenzyme profile didnāt change, new highly acidic POD isoforms replaced the two mildly acidic
isoforms, suggesting their specific role in slowing the progression of infection. Presented results
add to knowledge of events and mechanisms related to hemibiotrophic fungi pathogenicity in
succulent plants grown under high relative humidity, similar to conditions in greenhouse
Efekti selenita na metabolizam glutationa kod gljive Phycomyces blakesleeanus
Elementarni selen je najmanje biotoksiÄan oblik selena u prirodi, dok selen-oksianjoni mogu biti toksiÄni zbog znaÄajne pokretljivosti i rastvorljivosti u vodi. MikrobioloÅ”ka redukcija selena +4 (selenit) u elementarni selen je stoga od presudnog znaÄaja za smanjenje bioraspoloživosti ovog elementa.1 Visoka reaktivnost selen-oksianjona sa tiolnim grupama, kao i formiranje kiseoniÄnih radikala u reakciji sa glutationom implicira da oksidativni stres doprinosi toksiÄnosti selena.2 Tokom bioloÅ”ke redukcije selenita se proizvodi velika koliÄina peroksida Äime se indukuje ekspresija gena koji kodiraju enzime antioksidativnog metabolizma, Å”to ukljuÄuje i enzime metabolizma glutationa.1 Micelijum gljive Phycomyces blakesleeanus star 24 sata je tretiran 10 mM rastvorom selenita. Uzorci su nakon odreÄenih vremenskih intervala (1, 5, 10, 30, 60 minuta, 24 i 96 sati) ispirani i homogenizovani, nakon Äega je meren sadržaj glutationa i specifiÄna aktivnost enzima: peroksidaza (POD), katalaza (CAT), superoksid dismutaza (SOD), glutation peroksidaze (GPx), glutation-S-transferaze (GST) i glutation reduktaze (GR). Nakon dodavanja selenita utvrÄen je pad koliÄine ukupnog glutationa u micelijumu. Aktivnost POD i SOD je rasla do 60 minuta, nakon Äega je opadala. Aktivnost CAT opadala je odmah po dodatku selenita. Najizraženija je bila promena aktivnosti GPx gde je zabeležen znaÄajan porast, dok su promene aktivnosti GST i GR bile manje izražen
SELENITE METABOLISM IN THE MYCELIUM OF THE FUNGUS PHYCOMYCES BLAKESLEEANUS
In this study, mycelium of fungus Phycomyces blakesleeanus was exposed to soluble toxic form of selenium, selenite (Se+4), with the aim of determining the flow and products of its biotransformation. Selenite is reduced to Se0 in the form selenium nanoparticles (SeNPs) and Se-2 in the form of methylated volatile selenides. Low concentrations of Se+4 in the mycelium form RSSeSR type compounds, which could be a step in the process of SeNPs formation, or incorporation of Se into metabolites such as Se-amino acids
PRODUCTION AND CHARACTERISATION OF SELENIUM NANOPARTICLES BY MYCELIUM OF FUNGUS PHYCOMYCES BLAKESLEEANUS
In this study, mycelium of fungus Phycomyces blakesleeanus was exposed to soluble toxic form of selenium, selenite (Se+4), to examine its ability to reduce it to nanoparticles. Red coloration appeared after only a few hours of incubation with 10 mM Se+4 indicating formation of selenium nanoparticles (SeNPs). SEM-EDS confirmed pure selenium NPs with an average diameter of 57 nm, which indicates to potentially very good medical, optical and photoelectric characteristics. Raman spectroscopy showed several structural forms of SeNPs formed in the extracellular space with a monoclinic Se8 chain as the most represented, and the other observed forms were trigonal Se polymer chain, Se8 ring and Se6 chain structures