Effects of polyaluminum chloride (PAX-18) on the relationship between predatory fungi and Lecane rotifers.

PAX-18 (polyaluminum chloride) is frequently used in WWTPs (wastewater treatment plants) to overcome sludge bulking. An alternative biological method is the usage of Lecane rotifers, which can be endangered by predacious fungi. We investigated the influence of different PAX-18 concentrations on the relationship between Lecane inermis and predacious fungi (Zoophagus and Lecophagus) differing in feeding mode. High PAX concentration (6 mg Al3+ L-1) strongly limited the number of the rotifers, which in low concentration (1.2 mg Al3+ L-1), after an initial decline, increased, but significantly slower than in control. Under the simultaneous influence of Lecophagus and PAX, rotifers were driven almost extinct at the high concentration, but survived at the lower concentration and increased in the control. When treated with Zoophagus, only one or two rotifers survived in treatments and control. High concentrations of PAX significantly restricted the growth of fungi, whereas in low concentrations and control conditions, their length increased, with Zoophagus growing much quicker than Lecophagus. Zoophagus was significantly more efficient in trapping rotifers regardless of PAX concentration. The trapping ability of mycelium following extended exposure to PAX was strongly limited at high concentrations, in comparison to control. Conidia of Zoophagus turned out to be considerably more resistant to PAX-18 and starvation than Lecophagus conidia.

Toxicological Assessment of Cross-Linked Beads of Chitosan-Alginate and Aspergillus australensis Biomass, with Efficiency as Biosorbent for Copper Removal.

Sorbent materials of biological origin are considered as an alternative to the use of traditional methods in order to remove heavy metals. Interest in using these materials has increased over the past years due to their low cost and friendliness to the environment. The objective of this study was to synthesize and characterize cross-linked beads made of chitosan, alginate, and mycelium of a copper-tolerant strain of Aspergillus australensis. The acute toxicity of the biocomposite beads was assessed using brine shrimp Artemia salina nauplii and the phytotoxicity was determined using lettuce (Lactuca sativa) and chili pepper 'Anaheim' (Capsicum annuum) seeds. The biosorption capacity for copper removal in simulated wastewater was also evaluated. Results showed that the biosorbent obtained had a maximal adsorption of 26.1 mg of Cu2+ per g of biocomposite, and removal efficiency was around 79%. The toxicity of simulated residual water after treatment with the biocomposite showed low toxicity toward seeds, which was highly dependent on the residual copper concentration. The toxicity of the biocomposite beads to A. salina was considered medium depending on the amount of the biocomposite, which was attributed to low pH. Biocomposite shows promise as biosorbent for the removal process of heavy metals.

Bifunctional Small Molecules Enhance Neutrophil Activities Against Aspergillus fumigatus in vivo and in vitro.

Aspergillosis is difficult to treat and carries a high mortality rate in immunocompromised patients. Neutrophils play a critical role in control of infection but may be diminished in number and function during immunosuppressive therapies. Here, we measure the effect of three bifunctional small molecules that target Aspergillus fumigatus and prime neutrophils to generate a more effective response against the pathogen. The molecules combine two moieties joined by a chemical linker: a targeting moiety (TM) that binds to the surface of the microbial target, and an effector moiety (EM) that interacts with chemoattractant receptors on human neutrophils. We report that the bifunctional compounds enhance the interactions between primary human neutrophils and A. fumigatus in vitro, using three microfluidic assay platforms. The bifunctional compounds significantly enhance the recruitment of neutrophils, increase hyphae killing by neutrophils in a uniform concentration of drug, and decrease hyphal tip growth velocity in the presence of neutrophils compared to the antifungal targeting moiety alone. We validated that the bifunctional compounds are also effective in vivo, using a zebrafish infection model with neutrophils expressing the appropriate EM receptor. We measured significantly increased phagocytosis of A. fumigatus conidia by neutrophils expressing the EM receptor in the presence of the compounds compared to receptor-negative cells. Finally, we demonstrate that treatment with our lead compound significantly improved the antifungal activity of neutrophils from immunosuppressed patients ex vivo. This type of bifunctional compounds strategy may be utilized to redirect the immune system to destroy fungal, bacterial, and viral pathogens.

Assessing the stability in dry mycelial fertilizer of Penicillium chrysogenum as soil amendment via fluorescence excitation-emission matrix spectra: organic matter's transformation and maturity.

Utilization as dry mycelial fertilizer (DMF) produced from penicillin fermentation fungi mycelium (PFFM) with an acid-heating pretreatment is a potential way. To study the transformation and stability of water-extractable organic matter in DMF-amended soil via fluorescence regional integration (FRI) of fluorescence excitation-emission matrix (EEM), a soil experiment in pot was carried out. The results showed that residual penicillin (about 32 mg/kg) was almost degraded in the first 5 days, indicating that the drug pollution was in control. The pH value, DOC, DON, and DOC/DON presented a classical profile, but germination index (GI) leveled off about 0.13 till day 13 in DMF-12% treatment due to the severe phytotoxicity. The addition of DMF significantly increased the soil microbial populations in contrast to the CON treatment. The EEM showed that the protein-like and microbial byproduct-like matters vanished on the 25th and 33rd days, whereas the fulvic-like substances appeared on the 7th day. The humic-like substances existed in original samples but their content greatly enhanced finally. The FRI results showed that P V, n/P III, n reached the highest value of 1.84 on the 25th day, suggesting that DMF maintained stable in amended soil. Because of its consistency with the results of GI and DOC/DON, the EEM-FRI has a potential to evaluate the stability of DMF in soil.

The effect of visible light on gold nanoparticles and some bioeffects on environmental fungi.

The oxidative stress induced by light exposed gold nanoparticles in some microorganism cells was investigated. Gold nanoparticles are currently used in biomedical and pharmaceutical research. For this study citrate-gold nanoparticles were synthesized in alkaline conditions at constant temperature of 85°C under magnetic stirring. Equal volumes of such prepared colloidal solution, were exposed to visible light at different wavelengths for 90min at room temperature. The spectra in the visible and ultraviolet range have revealed an increase in the intensity of the absorption band for gold nanoparticles exposed to light, due to the effect of surface plasmon resonance. Versatility of gold nanoparticles photocatalytic action was shown by means of manipulating wavelengths of incident light, which evidenced differences in the bioeffects induced in cellulolytic fungi - known for their environmental role but also for other applications such as in cosmetics industry. The comparative analysis of fungal response to gold nanoparticle stressors has revealed different enzyme activity and lipid peroxidation when fungi were supplied with gold nanoparticles exposed to different wavelength lights. The activity of catalase and superoxide dismutase were remarkably increased for green light exposure of gold nanoparticles suggesting fungi adaption to increased oxidative stress induced by irradiated particles; increased level of lipid peroxidation was showed by high concentration of malondialdehyde for white light exposed gold particles since antioxidant enzymes were less active.

Effect of dry mycelium of Penicillium chrysogenum fertilizer on soil microbial community composition, enzyme activities and snap bean growth.

The dry mycelium fertilizer (DMF) was produced from penicillin fermentation fungi mycelium (PFFM) following an acid-heating pretreatment to degrade the residual penicillin. In this study, it was applied into soil as fertilizer to investigate its effects on soil properties, phytotoxicity, microbial community composition, enzyme activities, and growth of snap bean in greenhouse. As the results show, pH, total nitrogen, total phosphorus, total potassium, and organic matter of soil with DMF treatments were generally higher than CON treatment. In addition, the applied DMF did not cause heavy metal and residual drug pollution of the modified soil. The lowest GI values (<0.3) were recorded at DMF8 (36 kg DMF/plat) on the first days after applying the fertilizer, indicating that severe phytotoxicity appeared in the DMF8-modified soil. Results of microbial population and enzyme activities illustrated that DMF was rapidly decomposed and the decomposition process significantly affected microbial growth and enzyme activities. The DMF-modified soil phytotoxicity decreased at the late fertilization time. DMF1 was considered as the optimum amount of DMF dose based on principal component analysis scores. Plant height and plant yield of snap bean were remarkably enhanced with the optimum DMF dose.