Anna Gorczyca

Physiological effect of multi-walled carbon nanotubes (MWCNTs) on conidia of the entomopathogenic fungus, Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes)

The aim of the investigation was to assess the influence of commercial and carboxylated multi-walled carbon nanotubes (MWCNTs) on conidia of the entomopathogenic fungus Paecilomyces fumosoroseus. The commercial MWCNTs had an external diameter of about 40–60 nm, a length of 300–600 nm, a specific density of 140 to 300 g/dm3 and a carbon content of above 80%. Carboxylated MWCNTs were obtained by oxidizing commercial MWCNT by heating in HNO3, filtering, washing with water and drying. Conidia after different times of contact (from 1 to 865 hours) with nanomaterials in aqueous solutions were cultured for linear and biomass growth. Growth and sporification of mycelium after culture were evaluated. MWCNTs are not greatly cytotoxic for P. fumosoroseus conidia in the applied concentrations. The linear growth of mycelium obtained from conidia after contact with nanotubes was inhibited only in 2 (out of 18) cases (ones for both kinds of nanotubes). Carboxylated nanotubes did not inhibit biomass growth at all, but commercial nanotubes inhibited biomass growth in 2 cases. Sporification was the feature most strongly modified by carbon nanotubes. The commercial nanotubes again more strongly limited sporification of mycelium than carboxylated nanotubes did. The relatively greater influence of commercial versus carboxylated nanotubes was observed in the experiments.

Metal-metal interactions in biological systems

In spite of a lack of acute toxicity of single metal ions, in 96 hour laboratory tests there was a long term toxicity againstS. carpocapsae andH. bacteriophora nematodes. The 96 hour laboratory tests were carried out in order to prove possible synergistic and antagonistic interactions between pairs of metal ions. Thus, the pairs of ions were arranged from each of Al, Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mo(VI), Ni(II), Sc(IV), V(V) and Zn on one side and Mn(II) and Mg on the other. Mn(II) and Mg ions considerably reduced the nematode mortality and increased their infectivity againstGalleria mellonella caterpillars.

Effect of nanosilver in wheat seedlings and Fusarium culmorum culture systems

The purpose of this study was to examine the effect of silver nanoparticles (AgNPs) produced using the high-voltage arc discharge method on the growth and metabolism of common wheat seedlings. Additionally, a simultaneous assessment of the AgNP-induced reduction in seedling infection by Fusarium culmorum (Fc) was performed. AgNP- and Fc-treated seedlings indicated that both factors considerably inhibited their growth. A significant Fc-induced reduction in seedling blight was observed following treatment with AgNPs; however, treatment with nanoparticles was also accompanied by a serious disintegration of the cell membranes of roots. Moreover, treatment with AgNPs increased the quantum efficiency of energy trapping in the PSII reaction centre (Fv/Fm) with a simultaneous decrease in energy dissipation in the form of heat. Induction of photosynthesis in the presence of AgNPs did not affect height but was reflected in higher total dry weight. Moreover, analysis of antioxidant enzyme activity typical for the stress response indicated the toxicity of AgNPs treatment compared to Fc treatment. Seedlings exposed to AgNP activity demonstrated accumulation of Ag in roots and its translocation to aerial parts, while the pathogen reduced both accumulation and translocation of this element.

Effect of Metal Ions on the Entomopathogenic Nematode Heterorhabditis Bacteriophora Poinar (Nematoda: Heterohabditidae) Under Laboratory Conditions

The effect of sixteen metal ions: Al, Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mg, Mn(II), Mo(VI), Ni(II), Pb(II), Se(IV), V(V), and Zn on the mortality and infectivity ofHeterorhabditis bacteriophora were observed over a 96 hr period. All ions except Pb(II) even at naturally unrealistic concentrations did not cause the mortality of the nematodes. A weak vitalizing effect could eventually be observed with Mn(II), Mg, Fe(III) and Ni(II) (Table 1). However, such treatment generally lowered infectivity of the nematodes with respect to wax moth caterpillars.Galleria mellonella. This effect was particularly significant with Ni(II) and Pb(II).

Metal-Metal Interactions in Biological Systems. Part V. Steinernema Carpocapsae (Steinernematidae) and Heterorhabditis Bacteriophora (Heterorhabditidae) Entomopathogenic Nematodes

In spite of a lack of acute toxicity of single metal ions, in 96 hour laboratory tests there was along term toxicity against S. carpocapsae and H. bacteriophora nematodes. The 96 hourlaboratory tests were carried out in order to prove possible synergistic and antagonisticinteractions between pairs of metal ions. Thus, the pairs of ions were arranged from each of Al,Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mo(VI), Ni(II), Se(IV), V(V) and Zn on one sideand Mn(II) and Mg on the other. Mn(II) and Mg ions considerably reduced the nematodemortality and increased their infectivity against Galleria mellonella caterpillars.

The physiological effects of multi-walled carbon nanotubes (MWCNTs) on conidia and the development of the entomopathogenic fungus, Metarhizium anisopliae (Metsch.) Sorok

The aim of the study was an in vitro evaluation of the effect of MWCNTs on the conidia of two strains of entomopathogenic fungus, Metarhizium anisopliae. The study made use of water suspensions of MWCNTs (concentration ∼ 3 mg·mL−1) made from commercial nanotubes and centrifuged. The conidia were placed in contact with nanotubes for 240 h. An assessment of MWCNT influence on conidia was performed after 1, 24, 72 and 240 h and focused on the linear growth of vegetative mycelium derived from these conidia, mycelium sporulation in subcultures and pathogenicity. Using TEM imaging, it was demonstrated that carbon nanotubes are able to damage cell membranes of the examined fungi conidia. However, the absence was noted of a significantly fungistatic effect of both MWCNT suspensions on the examined strains with respect to the physiological features in question. The increase in vegetative mycelium effected by spores after contact with MWCNTs was characterized by a slight modification in relation to the control. There was no strong trend (inhibition - stimulation), in relation to the effect of the tested suspension of carbon nanotubes, on the development of the vegetative mycelium in in vitro culture. Sporulation of the mycelium after completion of the culture only occurred in one case (strain Ma73F and culture of spores after 24-h contact with MWCNTs) significantly more intensely than in the controls. With respect to pathogenicity for test insects compared to the control strain, Ma73F spores grown from the longest contact with nanotubes suspensions performed significantly better. On the basis of the calculated of mycelium index growth rates and the time of death of the test insects (LT50), it was found that the adverse effects of water suspension MWCNTs on the spores of M. anisopliae were applied after a short contact with biological material. This indicates unfavorable physical rather than chemical effects on the tested cell. Over time, nanotube aggregation in water suspensions led to changes in their influence on the cells under examination.

Bioactivity of MWCNT in Conidia of Entomopathogenic Fungus Isaria fumosorosea

The bioactivity of three kinds of multi-walled carbon nanotubes (MWCNT) towards the conidia of entomopathogenic fungus Isaria fumosorosea was examined in an in vitro study. Commercial—raw and functionalized—carboxylated MWCNT were applied. A fungal conidia suspension was placed in contact with dispersed MWCNT over different time-periods. After contact with the nanomaterial, the conidia were cultured on dishes and both the linear vegetative mycelium growth and the sporulation and germination of the spores derived from the culture were investigated. Also, the pathogenicity of the conidia after contact with MWCNT was examined in relation to test larvae. No fungistatic activity of MWCNT relative to I. fumosorosea conidia was demonstrated. Conidia contact with MWCNT resulted in the following changes in vital processes in the subsequent culture compared to the control standard culture: (1) raw MWCNT limited mycelium inoculation, but the growth rate observed later in the log-phase was more intense; (2) after 24-h conidia contact with all MWCNT types, the mycelium sporulated the most intensively; longer contact resulted in sporulation process limitation. Germination of conidia after contact with the MWCNT was not significantly modified. Raw MWCNT potentiated conidia pathogenicity towards test insects. It was observed that carboxylation of MWCNT reduces the bioactivity of this nanomaterial towards the investigated conidia.

Physiological aspects of the interaction of multi-walled carbon nanotubes with Beauveria bassiana (Balsamo) Vuillem in entomopathogenic spores

The objective of the study was to evaluate the in vitro effect of aqueous suspensions of commercial multi-walled carbon nanotubes (MWCNTs) on spores of three entomopathogenic fungus species of Beauveria bassiana. Spores were placed in contact with MWCNTs for 1, 24, 72 and 216 h and then an in vitro evaluation in the subculture was performed on the linear growth of the vegetative mycelium of the spores after the contact with nanomaterial, as well as its sporulation after completion of the culture. No fungistatic effect of MWCNTs against B. bassiana spores was identified. Modification of vegetative mycelium surface growth in the culture of spores after contact with MWCNTs was mainly due to less effective inoculation, especially when shorter contact times with nanomaterial were applied. For one of the investigated strains, growth stimulation was observed in the culture of spores in contact with nanotubes for 72 and 216 h. Based on the significant intensification of sporulation observed in combination with the longest (216 h) contact with the investigated spore strains before culture with MWCNTs, it can be concluded that the tested nanomaterial constitutes a stress factor and may modify the metabolism of B. bassiana cells. Detailed evaluation of B. bassiana metabolic changes induced by MWCNTs should be conducted.

Physiological effects of nanosilver on vegetative mycelium, conidia and the development of the entomopathogenic fungus, Isaria fumosorosea

An assessment of the influence of water nanosilver suspension was made at a concentration of 10 mg·L−1 on biological material (i.e., vegetative mycelium and conidia of Isaria fumosorosea entomopathogen) on a background of the silver nitrate ionic form used. Conidia of I. fumosorosea treated with silver nitrate for more than 168 h were completely deactivated. The application of nanosilver on Isaria hyphae resulted in a quantitative limitation of mycelium growth and its weaker sporulation after culturing compared to the control. The pathogenicity of a conidial suspension obtained from such culturing towards test insects did not diverge from that observed in the standard culture. No obvious toxic effects of nanosilver were observed on I. fumosorosea conidia. Isaria conidia, after exposure to nanosilver over a period between 1 and 800 h, initially demonstrated weaker vegetative mycelium formation in culture on solid medium and, as a consequence, this mycelium often sporulated in a poorer manner. In one case, there was a significant stimulation of the sporulation process for nanosilver treatment before culture for 168 h. Concurrently, conidial suspensions obtained from the culture after exposure of over 168 h to nanosilver exhibited enhanced pathogenicity towards test insects, which may be considered a beneficial phenomenon in terms of the function played by Isaria in the whole environment. The reaction of conidia with nanosilver indicates the deactivation of conidia cells in suspensions and a possibility of selection in increased pathogenicity.