The contribution of deadwood to soil carbon dynamics in contrasting temperate forest ecosystems

Deadwood forms a significant carbon pool in forest systems and is a potential source of dissolved organic carbon (DOC) input to soil, yet little is known about how deadwood effects forest soil carbon cycling. Deadwood DOC inputs to soil may be retained through sorption or may prime microbial decomposition of existing organic matter to produce additional DOC. To determine impacts of deadwood on soil C cycling, we analysed surface soil from beneath deadwood or leaf litter only, along chronosequences of stands of lowland oak and upland Sitka spruce. The concentration and quality (by optical indices) of water-extracted soil DOC (water-extractable organic carbon; WEOC), in situ decomposition ‘tea bag index’ (TBI) parameters and enzymatic potential assays (β-D-cellubiosidase, β-glucosidase, β-xylosidase, leucine aminopeptidase, phosphatase, phenol oxidase) were determined. Presence of deadwood significantly (p < 0.05) increased WEOC concentration (~ 1.5 to ~ 1.75 times) in the mineral oak soil but had no effect on WEOC in spruce soils, potentially because spruce deadwood DOC inputs were masked by a high background of WEOC (1168 mg kg−1 soil) and/or were not retained through mineral sorption in the highly organic (~ 90% SOM) soil. TBI and enzyme evidence suggested that deadwood-derived DOC did not impact existing forest carbon pools via microbial priming, possibly due to the more humified/aromatic quality of DOC produced (humification index of 0.75 and 0.65 for deadwood and leaf litter WEOC, respectively). Forest carbon budgets, particularly those for mineral soils, may underestimate the quantity of DOC if derived from soil monitoring that does not include a deadwood component.

Domestic Birds as Source of Cryptococcus deuterogattii (AFLP6/VGII): Potential Risk for Cryptococcosis

Cryptococcosis is an infection caused by encapsulated basidiomycetous yeasts belonging to the Cryptococcus neoformans/Cryptococcus gattii species complexes. It is acquired through inhalation of infectious propagules, often resulting in meningitis and meningoencephalitis. The ecological niche of these agents is a wide variety of trees species, as well as pigeon, parrot and passerine excreta. The objective of this study was to isolate Cryptococcus yeasts from excreta of commercially traded parrots and passerines. The 237 samples were collected between October 2018 and April 2019 and processed using conventional methodologies. Nineteen colonies with a dark brown phenotype, caused by phenol oxidase activity, were isolated, suggesting the presence of pathogenic Cryptococcus yeasts. All isolates tested positive for urease activity. URA5-RFLP fingerprinting identified 14 isolates (68.4%) as C. neoformans (genotype AFLP1/VNI) and 5 (26.3%) as C. deuterogattii (genotype AFLP6/VGII). Multi-locus sequence typing was applied to investigate the relatedness of the C. deuterogattii isolates with those collected globally, showing that those originating from bird-excreta were genetically indistinguishable from some clinical isolates collected during the past two decades.

Iron oxide nanoparticles effect on growth, physiological traits and nutritional contents of Moringa oleifera grown in saline environment

Background Using of nanoparticles in various aspects of life including agriculture, medicine and industry is very crucial. One of the important source for Fe nutrition in plants is Iron oxide nanoparticles (Fe3O4NPs) due to its efficiency in releasing under different pH range. Thus, in the Model Farm of National Research Centre Egypt at El Tour South Sinai, a field experiment was carried out, to study the effect of different concentration of Fe3O4NPs (0, 20, 40, 60 ppm) on the physiological parameters and the nutritive value of Moringa under saline condition. Results The obtained results indicate that foliar spraying of Fe3O4NPs significantly promote growth (plant height, branches leaves number per plant, leaf area, stem diameter and biomass). Foliar treatment also increased photosynthetic pigments (chlo.a, chlo b, chlo a/b and carotenoids) and indole acetic acid (IAA) contents comparing with control. Hydrogen peroxide and lipid peroxidation contents of Moringa oleifera leaves were decreased significantly as compared with control plant. The maximum activities of antioxidant enzymes Peroxidase (POX), poly phenol oxidase (PPO), super oxide dismutase (SOD) and nitrate reductase (NR) were observed in plants treated with 40 ppm. Different concentrations of Fe3O4NPs increased significantly crude protein, crude fiber and ash percentages as well as, some nutrient contents of moringa leaves (N, P, K and K/Na) compared with untreated control plants, meanwhile decreased Na contents. Conclusion Treatment of Moringa oleifera plant with Fe3O4NPs at different concentrations greatly decrease the harmful effect of salinity on growth by its promotive role on different studied biochemical and physiological aspects.

A study of fungicidal and anti-phenol oxidase activity of some α-amino phosphonate derivatives

Background Developing new pesticides with multi-function may be a suitable strategy to save time and cost and reduce the emergence of resistant strains of pests and pathogens. The organophosphorus derivatives have not been widely used in agriculture as fungicides. In this work, a series of six α-amino phosphonate derivatives were prepared and tested for their fungicidal and anti-phenol oxidase activities. Results The prepared compounds revealed a promising anti-fungal activity against Macrophomina phaseolina and Pythium aphanidermatum, especially M4, with MIC of 62 mg/L for M. phaseolina. M4 did not affect the fungus permeability rate of the cell membrane; however, it displayed a significant efficiency on mycelial soluble protein content. M4 and M3 with a hydroxyl group on the aniline moiety exhibited an observed anti-phenol oxidase activity. M4 inhibited the enzyme at 1 mg/mL. The DFT theoretical study revealed a significant correlation between the substituents of aniline moiety and the bioactivity of the studied compounds. The negative charge conspicuously influenced the anti-phenol oxidase activity. Conclusions Our findings suggest the studied compounds as bases to design more effective α-amino phosphonate fungicides with additional anti-phenol oxidase activity. Graphic abstract

Pollen Diet—Properties and Impact on a Bee Colony

Diet is an important factor in the proper development of the individual and the entire colony. A pollen diet affects honey bees in a number of ways. It can stimulate the number and type of hemocytes, the total number of proteins, carbohydrates and lipids, affect the histology of the middle intestine, and ensure the correct ontogenesis of the larvae. Moreover, selected single-flower diets can stimulate the development of the pharyngeal glands that produce royal jelly, thus conditioning the development of secretory immunity. Selected single-species pollen may also increase the phenol oxidase concentration, which contributes to the humoral response. A honey bee diet based on multi-flower pollen is more desirable than a mono-flower diet, but must be properly balanced.

Collateral implications of carbon and metal pollution on carbon dioxide emission at land-water interface of the Ganga River

Atmospheric CO2- source- and- sink is among the most debated issues that have puzzled climate change geochemist for decades. Here, we tested whether heavy metal pollutants in river sediments favor preservation of organic matter through shielding microbial degradation. We measured CO2 emission and extracellular enzyme activities at land-water interface (LWI) of 7 sites along a 285 km main stem of the Ganga River and 60 locations up- and downstream of two contrasting point sources discharging urban (Assi drain; Asdr) and industrial (Ramnagar drain; Rmdr) wastewaters to the river. We found the lowest CO2 flux at Rmdr mouth characterized by the highest concentrations of Cu, Cr, Zn, Pb, Ni, and Cd. The fluxes were relatively higher at locations up-and down-stream Rmdr. Substrate induced respiration (SIR), protease, FDAase and β-D-glucosidase all showed a similar trend but phenol oxidase and alkaline phosphatase showed opposite trend at the main river stem and Asdr. Sites rich in terrestrially derived organic matter have high phenol oxidase activity with low CO2 emission. The CO2 emission in the main river stem showed curvilinear relationships with total heavy metals (∑THM; R2 = 0.68; P < 0.001) and TOC (R2 = 0.65; p < 0.001). The dynamic fit model of main stem data showed that the ∑THM above 337.4 µg g− 1 were able to significantly decrease the activities of protease, FDAase and β-D-glucosidase. The study has implications for understanding C-cycling in human-impacted river sediments where metal pollution shields microbial degradation consequently carbon and nutrient release; and merits attention towards river management decisions.

Interactive effect of biocontrol agents in the management of Fusarium rot in cardamom and its impact on plant defense mechanism

Cardamom plantations are subjected to constant threat due to the Fusarium rot disease caused by Fusarium oxysporum Schlecht which is pronounced during summer months. The current study deals with the identification of an effective and ecofriendly management practice for the disease through the use of biocontrol agents. Survey conducted between February and May 2019 revealed maximum disease severity and incidence in Pampadumpara panchayat of Nedumkandam block (84.40% and 100%) and minimum in Erattaar panchayat of Kattappanablock (50.40% and 60.00%). A pot culture experiment was conducted to study the effect of three bioagents (Glomus fasciculatum, Trichoderma asperellum and Pseudomonas fluorescens) individually as well as in combinations. Root inoculation of G. fasciculatum with basal application and spray with P. fluorescens as well as root inoculation of G. fasciculatum along with basal application of T. asperellum and P. fluorescens spray were identifiedto be effective against the disease. Disease suppression by the above bioagents was facilitated by reduced pathogen antagonist ratio in the soil, high level of mycorrhizal colonization in the roots and enhanced biochemical activity of defense enzymes like peroxidase, poly phenol oxidase and phenylalanine ammonia lyase in the plants.

Remediation of Oily Waste using Soil Organic Nutrient Stimulant

Aims: This present study aim at assessing the efficacy of soil-organic nutrient stimulant in the remediation of oily waste. Study design: Preparation of Soil-goat dung mix was used as stimulant for the remediation of oily waste. Place and duration of study: The study was carried out at the Department of Microbiology University of Uyo, Uyo, Akwa Ibom state, Nigeria in the dry season months of January - March Methodology: Remediation of oily waste using soil - organic (goat dung) nutrient stimulant was assessed for 12 weeks using standard culture-dependent microbiological, chemical and enzyme activity assay procedures. Results: The results indicate increased counts of hydrocarbon utilizing bacteria, fungi and actinomycetes with remediation time. Microorganisms belonging to the genera Bacillus, Pseudomonas, Acinetobacter, Alcaligenes, Serratia, Penicillium, Aspergillus, Cladosporium, Rhodococcus, Nocardia and Streptomyces were recovered from the remediated waste. The pH of the soil-goat dung treatment ranged from 6.5 ± 0.02 to 7.1 ± 0.05. Enzyme activity by dehydrogenase and urease were higher than phenol oxidase with time. PAHs were below detectable limits (< 0.01) and reduction in total petroleum hydrocarbon was 99.3% for the remediated waste. Conclusion: Overall, enhanced microbial activities correlated positively with reduction in Total Petroleum Hydrocarbon and PAH composition which resulted in ecofriendly waste product. Soil-goat dung stimulant can therefore serve as a cheap alternative in the management of oily waste.

Efficacy of some conventional fungicides and essential oils against tomato early blight disease

Fungicidal activity of nine selected conventional fungicides, identified five plant oils and their combined effect against A. solani, the causal pathogen of early blight on tomato. GC-MS analysis of the tested oils indicated that terpene hydrocarbons (97%) with cinnamaldehyde as the major compound; sulfur compounds; fatty acids and organo-sulfur-containing compounds were the main components in cinnamon, garlic, mustard and onion oils, respectively. In vitro, Speedcide® (difenoconazole) and Cabrioduo® (Dimethomorph + Pyraclostrobin) were the most effective against the A. solani fungus with EC50 values of 94.6 and 88.6 ppm respectively. Toledo® (Tebuconzole) achieved EC50 value of 631.2 ppm. Roxyl-M® was significantly more effective than Roxyl–plus® or Remik®. Speedcide® alone or mixed with mandipropamid or azoxystrobin in Revus-Top® or Cruze® were the lowest effective in vitro. Garlic and mustard oils were more effective in liquid media than solid one. Cinnamon, onion, garlic and bitter almond oils caused moderate fungi-toxicity against early blight pathogen and could be implemented in the IPM program. Lower EC50 values were obtained in case of combinations of fungicides with oils than separate treatments. Effect of the active conventional fungicides and plant oils on disease indices, relative disease control, chlorophyll content, sugar contents and poly phenol oxidase in tomato plants was also studied.

The Bifunctional Catalase-Phenol Oxidase of Mycothermus Thermophilum (MtCATPO) Increases the Antioxidant Capacities of its Ortho-Diphenolic Substrates and of Green and Black Tea Extracts

Catalase from the thermophilic fungus Mycothermus thermophilus is a bifunctional enzyme with a secondary phenol oxidase activity (CATPO). MtCATPO catalyses the oxidation of catechol, chlorogenic acid, caffeic acid and (+)-catechin to yield mainly dimers, and higher molecular weight oligomers and polymers. The role of this phenol oxidase activity is not known. Here, the antioxidant capacities (AC) of the phenolic substrates in the absence and presence of MtCATPO were compared. The oxidized products displayed enhanced AC reaching a maximum of 2.4-fold with catechol. Other phenol oxidases (laccase and tyrosinase) did not yield AC enhancement to the same extent. MtCATPO-treatment increased AC of green and black tea infusions, as well as water extracts of samples collected from a black tea production line up to 28%. The bifunctional MtCATPO appears to be an important antioxidant enzyme with a wide range of potential applications in the food, neutraceuticals and pharmaceuticals industry.