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The predatory mite Neoseiulus longispinosus (Evans, 1952) isused as a specialized acariphage on vegetable, flower and berry crops inAsia. In protected ground of European agriculture, N. californicus is one ofthe effective predators of spider mites (Tetranychidae). The periodicity ofattacks on the victim depends on the temperature. The predator prefers tohunt immature individuals of T. urticae, often ignoring adult female spidermites if there is a choice. N. longispinosus does not show preferencebetween eggs and T. urticae nymphs. However, as the density of the spidermite population increases, the predatory mite switches its diet from theeggs to its larvae and nymphs. Adult females of N. californicus exhibit atype 2 functional response to both eggs and T. urticae nymphs. Pyrethroidand avermectin substances are highly toxic to predator populations, despitelow acute toxicity of many other insecticides (Actara, Envidor, etc.).

This article proposes a new method for determining the pathological state of a plant, based on a combination of the method for measuring the dynamics of photosystem II pigment fluorescence in the leaves of L. sativa plants and analyzing the resulting time series using bispectral analysis based on the wavelet transform. The article theoretically shows a possible mechanism for the appearance of a peak on the map of bispectrum indexes during nonlinear analog conversion of a physiological signal in a biological object. The phenomenon of increasing the degree of nonlinearity in the transmission of an external periodic signal in plant signaling systems has been experimentally demonstrated. [ABSTRACT FROM AUTHOR]

Introduction: The process of laser-induced breakdown of amorphous and crystalline selenium nanoparticles (Se NPs) of various shapes during nanosecond laser fragmentation of aqueous colloidal solutions of nanoparticles with different concentrations has been studied. Methods: The methods of studying the characteristics of plasma and acoustic oscillations induced by optical breakdown are applied. The methods of assessing the concentration of hydrogen peroxide and hydroxyl radicals, the amount of long-lived reactive species of protein and 8-oxoguanine are applied. Results: It has been established that in the process of laser fragmentation of selenium nanoparticles at a wavelength of 532 nm, corresponding to the maximum absorption of selenium, the highest probability of breakdown, the number of plasma flashes, their luminosity and the amplitude of acoustic signals are achieved at concentrations of the order of 109 NPs/mL. It has been shown that the use of selenium nanoparticles of various shapes and structures leads to a change in the photoacoustic signal during laser-induced breakdown. When crystalline selenium nanoparticles are irradiated, the intensity of the photoacoustic response during breakdown turns out to be greater (1.5 times for flash luminosity and 3 times for acoustics) than when amorphous particles are irradiated at the same concentration. It has been shown that selenium nanoparticles exhibit significant antioxidant properties. Selenium nanoparticles effectively prevent the formation of reactive oxygen species (ROS) during water radiolysis, eliminate radiation-induced long-lived reactive species of protein, and reduce the radiation-chemical yield of a key marker of oxidative DNA damage 8-oxoguanine. Discussion: In general, the intensity of processes occurring during laser fragmentation of amorphous and crystalline selenium nanoparticles differs significantly. The antioxidant properties are more pronounced in amorphous selenium nanoparticles compared to crystalline selenium nanoparticles. [ABSTRACT FROM AUTHOR]

In this work, we investigated the effect of photoconversion covers based on ruby (chromium-doped alumina (Al2O3:Cr3+)) particles (PCC-R) on the growth and development of lettuce (Lactuca sativa) plants. Ruby particles (from 100 nm to 2 μm) were obtained by the sequential application of spall laser ablation and further laser fragmentation. The content of chromium ions relative to aluminum ions in the nanoparticles was 3.3 × 10−3. The covers with different densities of applied ruby particles (2 × 107 m−2 (PCC-R7), 2 × 108 m−2 (PCC-R8), 2 × 109 m−2 (PCC-R9)) were studied in the present work. The PCC-Rs had two wide bands of luminescence excitation. The first one was from 350 nm to 450 nm with a maximum at 405 nm, and the second one was from 500 nm to 600 nm with a peak at 550 nm. Synthesized covers emitted in the range of 650 nm to 750 nm, with a peak at 695 nm. It has been shown that PCC-R8, in contrast to PCC-R7 and PCC-R9, provided an increase in yield by 40% and was characterized by increased water use efficiency during dark respiration and assimilation of carbon dioxide in plants. It is assumed that the observed positive effect of PCC-R8 photoconversion covers is associated with the activation of regulatory mechanisms due to a qualitative change in the light spectrum. [ABSTRACT FROM AUTHOR]

The effect of osmolytes (trehalose, sucrose, betaine, D-glucose and hydroxyectoine) on the photoassembly of the functionally active inorganic core of the water-oxidizing complex (Mn4CaO5 cluster) in Mn-depleted PSII preparations (apo-WOC-PSII) was investigated. It was revealed that the efficiency of the photoassembly of the Mn4CaO5 cluster was considerably (three times) increased in the presence of 1 M disaccharides (trehalose or sucrose) in contrast to other osmolytes. It was found that the osmolytes (especially trehalose or sucrose) improved the redox interaction of exogenous Mn2+ with apo-WOC-PSII, enhanced the protective effect of Mn2+ against the photoinhibition of apo-WOC-PSII, protected CaCl2-treated PSII preparations against thermoinactivation, and stabilized the water-oxidizing complex and electron transport from QA to QB in native PSII preparations during heat treatment. It is suggested that the ability of osmolytes to enhance the efficiency of the photoassembly of a Mn4CaO5 cluster depends on their effect on the following key processes: the redox interaction of Mn2+ with apo-WOC-PSII; the stability of apo-WOC-PSII to photoinhibition during the photoactivation procedure; and the stabilization of both the newly assembled functionally active Mn4CaO5 cluster and the electron transfer from QA to QB. [ABSTRACT FROM AUTHOR]

The bacterial contamination of cutting boards and other equipment in the meat processing industry is one of the key reasons for reducing the shelf life and consumer properties of products. There are two ways to solve this problem. The first option is to create coatings with increased strength in order to prevent the formation of micro damages that are favorable for bacterial growth. The second possibility is to create materials with antimicrobial properties. The use of polytetrafluoroethylene (PTFE) coatings with the addition of metal oxide nanoparticles will allow to the achieving of both strength and bacteriostatic effects at the same time. In the present study, a new coating based on PTFE and Fe2O3 nanoparticles was developed. Fe2O3 nanoparticles were synthesized by laser ablation in water and transferred into acetone using the developed procedures. An acetone-based colloidal solution was mixed with a PTFE-based varnish. Composites with concentrations of Fe2O3 nanoparticles from 0.001–0.1% were synthesized. We studied the effect of the obtained material on the generation of ROS (hydrogen peroxide and hydroxyl radicals), 8-oxoguanine, and long-lived active forms of proteins. It was found that PTFE did not affect the generation of all the studied compounds, and the addition of Fe2O3 nanoparticles increased the generation of H2O2 and hydroxyl radicals by up to 6 and 7 times, respectively. The generation of 8-oxoguanine and long-lived reactive protein species in the presence of PTFE/Fe2O3 NPs at 0.1% increased by 2 and 3 times, respectively. The bacteriostatic and cytotoxic effects of the developed material were studied. PTFE with the addition of Fe2O3 nanoparticles, at a concentration of 0.001% or more, inhibited the growth of E. coli by 2–5 times compared to the control or PTFE without NPs. At the same time, PTFE, even with the addition of 0.1% Fe2O3 nanoparticles, did not significantly impact the survival of eukaryotic cells. It was assumed that the resulting composite material could be used to cover cutting boards and other polymeric surfaces in the meat processing industry. [ABSTRACT FROM AUTHOR]

Development of eco-friendly and biodegradable package materials is an important goal of modern science and international industry. Poly(lactic)-co-glycolic acid (PLGA) is suitable for this purpose. However, biocompatible materials may be contaminated with bacteria. This problem may be solved by the addition of metal oxides nanoparticles (NPs) with antibacterial properties. Although metal oxides NPs often show cytotoxicity against plant and mammalian cells, a new nanocomposite based on PLGA and aluminum oxide (Al2O3) NPs has been developed. The PLGA/Al2O3 NP composite has pronounced antibacterial properties. The addition of Al2O3 NPs 0.01% inhibited growth of E. coli for >50%. The antimicrobial effect of Al2O3 NPs is implemented through the generation of reactive oxygen species and damage of bacterial proteins and DNA. The biocompatibility of the nanocomposite with plant and mammalian cells was studied. The PLGA/Al2O3 NP composite did not influence the growth and development of tomatoes and cucumbers. PLGA and its composite with Al2O3 NPs 0.001–0.1% did not influence viability and proliferation of mammalian cells, on their density or substrate colonization rate. The developed nanocomposite has controlled mechanical properties, high antibacterial activity and high biocompatibility, which makes it an attractive candidate for building and food package material manufacture and agriculture. [ABSTRACT FROM AUTHOR]