Algae, shrimp grazing, and fecal pellets synergistically increase microbial activity and enhance N immobilization during Typha angustifolia leaf litter decomposition.

Algae play an important role in ecological processes of aquatic ecosystems. Understanding the interactive effects of algae with invertebrates in litter decomposition is important for predicting the effects of global change on aquatic ecosystems. We manipulated Typha angustifolia litter to control exposure to shrimp fecal pellets and/or grazing, and the green alga Chlorella vulgaris were added to test their interactive effects on T. angustifolia litter decomposition. Our results showed that algae largely shortened microbial conditioning time and improved litter palatability (increasing litter quality), resulting in greater decomposition and higher fecal pellet production. Fecal pellets enhanced grazing effects on decomposition by increasing litter ash content. The effects of algae and especially fecal pellets on decomposition were dependent on or mediated by grazing. Without grazing, algae slightly promoted decomposition and marginally offset the negative effect of fecal pellets on litter decomposition. Shrimp grazing dramatically decreased microbial activity (extracellular enzyme activity and microbial respiration) at microbial conditioning stage while enhanced microbial activity after 84 days especially with both algae and fecal pellets present. Algae significantly upregulated N- and P-acquiring and slightly downregulated C-acquiring enzyme activity. Fecal pellets significantly depressed recalcitrant C-decomposition enzyme activity. Nevertheless, the three factors synergistically and significantly increased C loss and most enzyme activities, microbial respiration, and N immobilization, resulting in the decrease of litter C:N. Our results reveal the synergistic action of different trophic levels (autotrophs, heterotrophs, and primary consumers) in the complicated nutrient pathways of litter decomposition and provide support for predicting the effects of global changes (e.g., N deposition and CO2 enrichment), which have dramatically effects on alga dynamics and on ecological processes in aquatic ecosystems.

Insight into nitrogen and phosphorus enrichment on cadmium phytoextraction of hydroponically grown Salix matsudana Koidz cuttings.

Cadmium (Cd) has already caused worldwide concern because of its high biotoxicity to human and plants. This study investigated how nitrogen (N) and phosphorus (P) enrichment alter the toxic morpho-physiological impacts of and accumulation of Cd in hydroponically grown Salix matsudana Koidz cuttings. Our results showed that Cd significantly depressed growth and induced a physiological response on S. matsudana cuttings, exhibiting by reduced biomass, decreased photosynthetic pigment concentrations, and increased soluble protein and peroxidase activity of shoots and roots. N and P enrichment alleviated the Cd toxic effects by increasing production of proline which prevented cuttings from damage by Cd-induced ROS, displaying with decreased malondialdehyde concentration, and stimulated overall Cd accumulation. Enrichment of N and P significantly decreased the upward Cd transfer, combing with enhanced root uptake (stimulated root activity) and retranslocation from stem, resulted in extensive Cd sequestration in S. matsudana roots. In both root and xylem, concentration of Cd is positively correlated with N and P. The improved phytoextraction potential by N and P enrichment was mainly via elevating Cd concentration in roots, probably by increased production of phytochelatins (e.g., proline) which form Cd chelates and help preventing damage from Cd-induced ROS. This study provides support for the application of S. matsudana in Cd phytoextraction even in eutrophic aquatic environments.

Proteomic analysis reveals large amounts of decomposition enzymes and major metabolic pathways involved in algicidal process of Trametes versicolor F21a.

A recent algicidal mode indicates that fungal mycelia can wrap and eliminate almost all co-cultivated algal cells within a short time span. However, the underlying molecular mechanism is rarely understood. We applied proteomic analysis to investigate the algicidal process of Trametes versicolor F21a and identified 3,754 fungal proteins. Of these, 30 fungal enzymes with endo- or exoglycosidase activities such as ß-1,3-glucanase, α-galactosidase, α-glucosidase, alginate lyase and chondroitin lyase were significantly up-regulated. These proteins belong to Glycoside Hydrolases, Auxiliary Activities, Carbohydrate Esterases and Polysaccharide Lyases, suggesting that these enzymes may degrade lipopolysaccharides, peptidoglycans and alginic acid of algal cells. Additionally, peptidase, exonuclease, manganese peroxidase and cytochrome c peroxidase, which decompose proteins and DNA or convert other small molecules of algal cells, could be other major decomposition enzymes. Gene Ontology and KEGG pathway enrichment analysis demonstrated that pyruvate metabolism and tricarboxylic acid cycle pathways play a critical role in response to adverse environment via increasing energy production to synthesize lytic enzymes or uptake molecules. Carbon metabolism, selenocompound metabolism, sulfur assimilation and metabolism, as well as several amino acid biosynthesis pathways could play vital roles in the synthesis of nutrients required by fungal mycelia.

One new antitumour cassane-type diterpene from Caesalpinia crista.

1α-acetoxy-5α, 7ß-dihydroxycassa-11,13(15)-diene-16,12-lactone, a new cassane-type diterpene was isolated from Caesalpinia crista. The structure of this compound was elucidated by analysis of NMR spectra, and the relative configuration was established by NOE experiment. The new compound was evaluated for antitumour activity against T47D, DU145 and showed significant inhibitory activities.

Isolation and evaluation of terrestrial fungi with algicidal ability from Zijin Mountain, Nanjing, China.

Approximately 60 fungal isolates from Zijin Mountain (Nanjing, China) were screened to determine their algicidal ability. The results show that 8 fungi belonging to Ascomycota and 5 belonging to Basidiomycota have algicidal ability. Of these fungi, Irpex lacteus T2b, Trametes hirsuta T24, Trametes versicolor F21a, and Bjerkandera adusta T1 showed strong algicidal ability. The order of fungal chlorophyll-a removal efficiency was as follows: T. versicolor F21a > I. lacteus T2b > B. adusta T1 > T. hirsuta T24. In particular, T. versicolor F21a completely removed algal cells within 30 h, showing the strongest algicidal ability. The results also show that all 4 fungal species degraded algal cells through direct attack. In addition, most of the tested fungi from the order Polyporales of Basidiomycota exhibited strong algicidal activity, suggesting that most fungi that belong to this order have algicidal ability. The findings of this work could direct the search for terrestrial fungi for bloom control.

Synthesis, structure, molecular docking, and structure-activity relationship analysis of enamines: 3-aryl-4-alkylaminofuran-2(5H)-ones as potential antibacterials.

Thirty-one 3-aryl-4-alkylaminofuran-2(5H)-ones were designed, prepared and tested for their antibacterial activity. Some of them showed significant antibacterial activity against Gram-positive organisms, especially against Staphylococcus aureus ATCC 25923, but all were inactive against Gram-negative organisms. Out of these compounds, 3-(4-bromophenyl)-4-(2-(4-nitrophenyl)hydrazinyl)furan-2(5H)-one (4a11) showed the most potent antibacterial activity against S. aureus ATCC 25923 with MIC(50) of 0.42 µg/mL. The enzyme assay revealed that the possible antibacterial mechanism of the synthetic compounds might be due to their inhibitory activity against tyrosyl-tRNA synthetase. Molecular dockings of 4a11 into S. aureus tyrosyl-tRNA synthetase active site were also performed. This inhibitor snugly fitting the active site might well explain its excellent inhibitory activity. Meanwhile, this modeling disclosed that a more suitable optimization strategy might be to modify the benzene ring at 3-position of furanone with hydrophilic groups.

Removal of crystal violet from aqueous solution using powdered mycelial biomass of Ceriporia lacerata P2.

A biosorbent prepared from powdered mycelial biomass of Ceriporia lacerata (CLB), a basidiomycetous fungus, was applied for the uptake of Crystal Violet from aqueous solution. A batch adsorption experiment was used for the biosorption process, involving effect of experimental factors and biosorption kinetics and equilibrium. Biosorption process showed that the removal of Crystal Violet by CLB was effective over wide pH range, and meanwhile was independent on ionic strength. Biosorption capacities of CLB increased with the initial dye concentration increasing, due to an increase in the driving force of the concentration gradient. The adsorbed Crystal Violet amount per unit biomass weight decreased with increasing biosorbent dosage, due to the splitting effect of flux (concentration gradient) between sorbate and biosorbent. A maximum sorption capacity of 239.25 mg/g was observed. Biosorption kinetics was found to be best represented by the pseudo second-order kinetic model. The equilibrium adsorption data was well described by the Koble-Corrigan model. FT-IR (Fourier Transform Infrared Spetroscopy) spectrum showed the presence of O-H, COOH, C=O, C-N, C-H, -NH2 and P-OH in the surface of CLB as functional groups. This study showed CLB can effectively remove CV from dye wastewater.

Decomposing ability of filamentous fungi on litter is involved in a subtropical mixed forest.

The abilities of 10 filamentous fungi, isolated from Pinus massoniana-Liquidambar formasana mixed forest (PLF), to decompose fresh, fallen needle and leaf litter were studied with pure-culture tests. The results showed that all fungi except Mucor sp. and Chaetomium bostrychodes could drive mass loss of L. formasana leaf litter significantly more than that of P. massoniasa. Mass loss of litter in the first 5 wk of the study was higher than that in the last 5 wk. The decomposition rate was negatively correlated to the original lignin/nitrogen (L/N) and carbohydrate/nitrogen (C/N) ratios. Based on the mass loss of litter (W), carbohydrate (C) and lignin (L), and the mutual relationship between L/W and L/C ratio, we concluded that Mucor sp. had the lowest decomposing ability on P. Massoniana and L. formasana litter and that it could not use lignin. The Chaetomium bostrychodes were lignin and carbohydrate decomposers but preferred lignin. Trichoderma sp. 1 and Cladosporium herbarum were carbohydrate-decomposing fungi. Trichoderma sp. 2, Aspergillus fumigatus, Alternaria sp. and Penicillium sp. 2 were able to decompose lignin and carbohydrate but preferred carbohydrate and had high ability to decompose litter. Aspergillus niger and Penicillium sp. 1 were able to decompose lignin and carbohydrate only in the early phase of the study. The decomposing ability of fungi varied even within genus. No direct relationship was found between the frequency of isolation and the decomposing ability of fungi.

Equilibrium and kinetic studies of copper(II) removal by three species of dead fungal biomasses.

The batch experiments were conducted to study the copper(II) removal by formaldehyde inactivated Cladosporium cladosporioides, Gliomastix murorum and Bjerkandera sp., at conditions of agitation speed of 150 rpm, temperature of 25 degrees C, biosorbent dose of 2 g l(-1) and contact time of 12h. It was found that, for each biomass, the optimum pH was 6.0 and the equilibrium establishing time was about 2h. Without acid or alkali treatment for improving adsorption properties, the experimental maximum copper(II) biosorptions were relatively high: 7.74 mg g(-1) for C. cladosporioides, 9.01 mg g(-1) for G. murorum, and 12.08 mg g(-1) for Bjerkandera sp.. The biosorption data of all the dead fungal biomasses were quite fitted to Langmuir isotherm model and pseudo second-order kinetic model; first-order Lagergren kinetic model gave good adjustment to the data of Bjerkandera sp. but did not fit the data of C. cladosporioides and G. murorum very well. These fungal biomasses exhibited relatively high capacity for the removal of copper(II) from aqueous solutions.

Involvement of lignocellulolytic enzymes in the decomposition of leaf litter in a subtropical forest.

The involvement of ligninolytic and cellulolytic enzymes, such as laccase, lignin peroxidase, manganese peroxidase, carboxymethylcellulase (CMCase), and filter paper activity (FPA), in the decomposition process of leaf litter driven by 6 soil-inhabiting fungi imperfecti was studied under solid-state fermentations. All the tested fungi exhibited varied production profiles of lignocellulolytic enzymes and each caused different losses in total organic matter (TOM) during decomposition. Based on the results, the 6 fungi could be divided into 2 functional groups: Group 1 includes Alternaria sp., Penicillium sp., Acremonium sp., and Trichoderma sp., and Group 2 includes Pestalotiopsis sp. and Aspergillus fumigatus. Group 1, with higher CMCase and FPA activities, showed a higher decomposition rate than the fungi of Group 2 over the first 16 d, and thereafter the cellulolytic activities and decomposition rate slowed down. Group 2 showed the maximum and significantly higher CMCase and FPA activities than those of the Group 1 fungi during the later days. This, combined with the much higher laccase activity, produced a synergistic reaction that led to a much faster average mass loss rate. These results suggest that the fungi of Group 1 are efficient decomposers of cellulose and that the fungi of Group 2 are efficient decomposers of lignocellulose. During cultivation, Pestalotiopsis sp. produced an appreciable amount of laccase activity (0.56+/-0.09 U/ml) without the addition of inducers and caused a loss in TOM of 38.2%+/-3.0%, suggesting that it has high potential to be a new efficient laccase-producing fungus.