Biocontrol strains from the genera Bacillus and Pseudomonas and their bioactive secondary metabolites may be considered beneficial for plant health, since they act through several mechanisms, ...including direct antibiosis, plant growth promotion and the induction of systemic resistance in the plant hosts. These beneficial bacteria have been proven to be very active against bacterial and fungal phytopathogens, nematodes and different insects. Direct antibiosis, an induced immune system response (ISR) in the host plant and competition for nutrients and space are the most common biocontrol potential of these genera. Species belonging to the Bacillus genus are commonly considered ideal due to their rapid growth, ease of handling and excellent colonizing properties. These endospore‐forming Bacillus strains are capable of suppressing and inhibiting plant pathogens, both indirectly by competing with the pathogens for a niche or nutrient requirements, or directly by producing various lipopeptide compounds such as iturin, surfactin and fengycin, which are active on many plant pathogens. Furthermore, they are also capable of inducing systemic resistance in plants through the production of volatile substances including alcohols, aldehydes, aromatics, sulfides and ketones. Lipopeptides, polyketides and volatiles from Bacillus spp. can stimulate the expression of genes coding for pathogenesis-related (PR) proteins and other defense-related proteins in the plant hosts through the activation of jasmonic acid (JA), salicylic acid (SA) or ethylene (ET) signaling pathways. In addition, inhibition of quorum sensing in competitive bacteria and the capability to downregulate expression of genes involved in mycelial growth, penetration, sporulation and the virulence of a fungal pathogen is another property of Bacillus strains and their volatiles. The Pseudomonas genus is rich in species with the potential for biocontrol with positive effects on plant welfare, which actively participate in complex plant-pathogen-antagonist interaction. The most common molecules involved in this mechanism are, among others, 2,4‐diacetylphloroglucinol, phenazine‐1‐carboxylic acid, phenazine-1-carboxamide, pyoluteorin and pyrrolnitrin. Cyclic lipopeptides from Pseudomonas spp. such as nunamycin, nunapeptin, brasmycin and braspeptin were intensively studied as agents for plant biocontrol and biostimulation in agriculture. Nunamycin, nunapeptin, brasmycin and braspeptin were identified as essential in the antifungal role. Furthermore, phenazines, sessilins and orfamides were shown to have additive roles in the suppression of some fungal diseases. Additionally, Bacillus and Pseudomonas spp. produce chitinases, glucanases and proteases involved in the suppression of many fungal diseases. Their production is mainly induced by the presence of fungal pathogen biomass and their cell wall. This review provides an updated overview of the antimicrobial activity of plant-associated Bacillus and Pseudomonas involved in plant disease suppression via biological control mechanisms, including their molecular basis and direct activity, offering a better understanding in preventing different pests.
•Bacillus and Pseudomonas spp. produce wide array of secondary metabolites.•Secondary metabolites are involved in biocontrol and biofertilization mechanisms.•Numerous phytopathogens are controlled by Bacillus and Pseudomonas isolates.•Molecular mechanisms of biocontrol activity are discussed.
Selenium (Se) is an essential element for humans and animals, with one of the narrowest ranges between deficiency (< 40 µg day
−1
) and toxicity (> 400 µg day
−1
). Se is very widespread in all ...environments (rocks, soils, waters, air, plant and animal tissue) but in very low concentrations. Thus, there are no ores from which Se can be effectively mined. This can create a potential problem in supplying Se for commercial uses or for battling Se deficiency which already affects more than one billion people and is predicted to rise in the future. Besides Se deficiency, there are many incidents where excess Se in water and soil caused deformities in animals and humans. Often high-Se areas are found near past coal mining and burning sites, which have never been remediated and still pose a potential threat to human health. This article aims to inform readers about the general chemical characteristics of Se, environmental cycling of Se, and past incidents of Se deficiency and toxicity. The article also touches on the removal of excess Se from waters and soils, as well as biofortification methods for preventing Se deficiency in humans and animals.
Coal combustion generates almost 40% of world's electricity. However, it also produces 1.1 billion tons of coal combustion residues (CCR) annually, half of which end up in landfills. Although current ...regulations require proper lining and monitoring programs, the ubiquitous old, abandoned landfills are often not lined nor included in these programs. In addition, the total number of coal ash disposal sites and their status in the world is unknown. Therefore, this article reviews the environmental damage caused by CCR and three commonly used risk assessment methodologies: leaching assessment, groundwater assessment, and toxicity testing.
Leaching methods are usually the first step in coal ash risk assessment, however, a large number of methods with different parameters make a comparison of data difficult. Groundwater pollution is commonly detected near coal ash disposal sites, but other anthropogenic activities may also exist nearby. Therefore, multivariate statistical methods and isotope traces should be used to differentiate between different sources of pollution. So far, both stable (δ18O, δD, δ11B, δ34S, δ7Li) and radiogenic (87Sr/86Sr, 206Pb/207Pb) isotopes have been successfully used as coal ash pollution tracers. Coal ash also negatively affects biota, reduces the diversity of organisms, affects children's health, and increases the risk for developing various diseases. Toxicity studies are great for early screening of coal ash safety; however, they provide no insights into mechanisms causing the adverse effects.
Future directions are also proposed, such as the development of new ‘low-level’ detection methods for coal ash pollution and sustainable and selective method for recovery of critical elements.
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•LEAF methods in combination with other analyzes allow a comprehensive risk assessment of coal ash.•Climate changes may further promote leaching from old coal ash disposal sites.•Isotope tracers are a powerful tool for characterizing and tracing coal ash leachate.•Synergistic effects of multiple contaminants should be considered when assessing toxicity.•Residents living near coal ash are at higher risk for cardiovascular and physiological disease.
One of the goals of this research was to develop an electrochemical sensor that had the ability to determine the target analyte and was both cheap and non-toxic. Another goal was to influence the ...reduction of electronic waste. In accordance with these, a graphite rod from zinc-carbon batteries was used to prepare an electrochemical sensor for the determination of L-tryptophan in Britton-Robinson buffer solution. Two electrochemical methods were used in the experimental research, differential pulse voltammetry and cyclic voltammetry. The effect of different parameters, including the pH value of supporting solution, scan rate, as well as the concentration of L-tryptophan on the current response, was studied. The pH value of Britton-Robinson buffer influenced the intensity of L-tryptophan oxidation peak, as well as the peak potential. The intensity of the current response was the highest at pH 4.0, while the peak potential value became lower as the pH increased, indicating that protons also participated in the redox reaction. Based on the obtained data, electrochemical oxidation of L-tryptophan at the graphite electrode was irreversible, two electron/two proton reaction. In addition, it was observed that the oxidation peak increased as the scan rate increased. According to the obtained electrochemical data, it was suggested that the oxidation of L-tryptophan was mixed controlled by adsorption and diffusion. The linear correlation between oxidation peak and L-tryptophan concentration was investigated in the range 5.0-150.0 µM and the obtained values of limit of detection and limit of quantification were 1.73 µM and 5.78 µM, respectively. Also, the prepared electrochemical sensor was successful in determination of target analyte in milk and apple juice samples.
Health care policies often rely on public cooperation, especially during a health crisis. However, a crisis is also a period of uncertainty and proliferation of health-related advice: while some ...people adhere to the official recommendations, others tend to avoid them and resort to non-evidence based, pseudoscientific practices. People prone to the latter are often the ones endorsing a set of epistemically suspect beliefs, with two being particularly relevant: conspiratorial pandemic-related beliefs, and the appeal to nature bias regarding COVID-19 (i.e., trusting natural immunity to fight the pandemic). These in turn are rooted in trust in different epistemic authorities, seen as mutually exclusive: trust in science and trust in the "wisdom of the common man". Drawing from two nationally representative probability samples, we tested a model in which trust in science/wisdom of the common man predicted COVID-19 vaccination status (Study 1, N = 1001) or vaccination status alongside use of pseudoscientific health practices (Study 2, N = 1010), through COVID-19 conspiratorial beliefs and the appeal to nature bias regarding COVID-19. As expected, epistemically suspect beliefs were interrelated, related to vaccination status, and to both types of trust. Moreover, trust in science had both a direct and indirect effect on vaccination status through both types of epistemically suspect beliefs. Trust in the wisdom of the common man had only an indirect effect on vaccination status. Contrary to the way they are typically portrayed, the two types of trust were unrelated. These results were largely replicated in the second study, in which we added pseudoscientific practices as an outcome; trust in science and the wisdom of the common man contributed to their prediction only indirectly, through epistemically suspect beliefs. We offer recommendations on how to make use of different types of epistemic authorities and how to tackle unfounded beliefs in communication during a health crisis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hydrochar produced via hydrothermal carbonization of grape pomace was considered as novel sorbent of Pb(2+) from aqueous solution. In order to enhance the adsorption capacity, hydrochar was ...chemically modified using 2 M KOH solution. Both materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction technique. Batch experiments were performed to examine the effect of sorbent dosage, pH and contact time. Obtained results showed that the KOH treatment increased the sorption capacity of hydrochar from 27.8 mg g(-1) up to 137 mg g(-1) at pH 5. Adsorption of lead on either of the materials was achieved through ion-exchange mechanism, chemisorption and Pb(2+)-π interaction. The Sips isotherm model gave the best fit with the experimental data obtained for Pb(2+) sorption using activated hydrochar. The adsorption kinetic followed a pseudo second-order model. Thermodynamic parameters implied that the Pb(2+) binding for hydrochar surface was spontaneous and exothermic process. Findings from this work suggest that the hydrothermal carbonization is a promising route for production of efficient Pb (2+) sorbents for wastewater treatment.
The determination of target analytes at very low concentrations is important for various fields such as the pharmaceutical industry, environmental protection, and the food industry. Caffeine, as a ...natural alkaloid, is widely consumed in various beverages and medicines. Apart from the beneficial effects for which it is used, caffeine also has negative effects, and for these reasons it is very important to determine its concentration in different mediums. Among numerous analytical techniques, electrochemical methods with appropriate sensors occupy a special place since they are efficient, fast, and entail relatively easy preparation and measurements. Electrochemical sensors based on carbon materials are very common in this type of research because they are cost-effective, have a wide potential range, and possess relative electrochemical inertness and electrocatalytic activity in various redox reactions. Additionally, these types of sensors could be modified to improve their analytical performances. The data available in the literature on the development and modification of electrochemical sensors for the determination of caffeine are summarized and discussed in this review.
Amidst the flow of conspiracy theories (CTs) about the COVID-19 pandemic, many were logically incompatible. We aimed to map the psychological profile of their endorsers. Upon pretesting for ...familiarity and logical incompatibility, we choose eight pairs of contradictory COVID-19 CTs. Across three studies, a substantial portion of respondents (40%-42%) endorsed at least one pair. In Study 1 (N = 290), conspiracy mentality and doublethink, but not preference for consistency, meaningfully related to endorsement of contradictory CTs; doublethink contributed over and above other predictors. In two following studies we introduced indicators of superficial (Study 2; N = 281) and analytical (Study 3; N = 170) information-processing as predictors. The endorsers of contradictory CTs were more intuitive, prone to ontological confusions and pseudo-profound bullshit, less rational and less actively open-minded; doublethink again added to the prediction. We end by suggesting how the interventions should be tailored to address people with such distinct information-processing style.
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•Raw corn silk as novel adsorbent for copper and zinc has been investigated.•Adsorption process of metal is favorable and occurs under monolayer surface.•The involvement of ...complexation and ion – exchange binding mechanisms is confirmed.•Adsorption process is feasible, spontaneous and endothermic.•Adsorbent can be efficiently regenerated and reused.
In this study the novel biosorbent – raw corn silk (CS) was investigated for Cu2+ and Zn2+ removal from aqueous solutions. The physical and chemical properties of CS were determined by SEM – EDX and ATR – FTIR techniques. The SEM micrographs revealed that surface morphology of CS is suitable for metal adsorption, while FTIR analysis confirmed presence of various active groups (OH, CO, COC, CC and amide II) which could interact with metal ions. The adsorption experiments were performed in batch system. Experimental data were fitted by pseudo – first order and pseudo – second order kinetic models as well as Langmuir and Freundlich isotherm models. Biosorption of the both metals follow pseudo second-order kinetic model. The best fitting adsorption model is Langmuir model and the maximum biosorption capacities (qmax) for Cu2+ and Zn2+ at 313K and pH 5.0 were 15.35mg g−1 and 13.98mgg−1, respectively. The thermodynamic parameters such as Gibbs free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS) were studied at different metal concentration and three temperatures. According to thermodynamic study, the biosorption process for both metals is feasible, endothermic and spontaneous. According to thermodynamic study, the biosorption process for both metals is feasible, endothermic and spontaneous. Ion – exchange is the dominant mechanism in adsorption of Cu2+ and Zn2+ on the CS with a certain degree of complexation. Desorption study was performed in three adsorption/desorption cycles with diluted nitric acid. Results show that after metal adsorption CS can be efficiently recovered and reused for new adsorption process. Obtained results indicated that corn silk could be used as efficient novel biosorbent for Cu2+ and Zn2+ removal from water samples.
A new biosorbent – alginate encapsulated with Myriophyllum spicatum – MsA was investigated for lead ions removal. This biosorbent was characterized by scanning electron microscopy (SEM), Fourier ...transform infrared spectroscopy (FT-IR), zeta potential, X ray Diffraction (XRD) and size distribution analysis. FT-IR analysis demonstrated that the lead ions sequestration mechanism included ion exchange and lead complexation with the carboxyl, carbonyl and hydroxyl groups in MsA. In order to better understand the mechanisms of the binding of Pb(II) on immobilized M. spicatum beads, 3 reaction and one diffusion based kinetic models were applied on kinetic data removal lead ions on three materials: M. spicatum, Ca-alginate and MsA. Myriophyllum spicatum encapsulated with alginate – MsA have higher adsorption capacity than M. spicatum. Among examined six isotherms Redlich-Peterson and the Langmuir isotherm model exhibited the best fit to the experimental data, with capacities ranging from 230 to 268.7 mg/g. Among the various tested desorption agents, nitric acid has proven to be the best. The obtained results suggest that the immobilized M. spicatum biosorbent holds great potential for lead wastewater treatment applications.
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•Lead biosorption by alginate immobilized aquatic weed M. spicatum was investigated.•The six isotherm and four kinetic models were fitted to experimental data.•Studies and characterization have showed the mechanism of Pb(II) removal.•Examined biosorbent holds great potential for lead removal qmax = 230 mg/g.
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