Objective. Study the biological activity of nickel nanoparticles (Ni NPs) against pathogenic viruses and fungi, pathogens of farm animals and plants, investigate their bactericidal and growthregulating properties. Methods. Virological, microbiological and statistical. Virucidal activity of NiNPs was evaluated by the difference of virus titres in the control and under the action of NPs, bactericidal — by the difference of bacterial titres, fungicidal and fungistatic — by the difference of diameters of fungal colonies, growth-regulating — by the difference in leaf blade length and roots ofgerms of winter wheat. The antiviral activity of NPs was determined in the culture of versenalisedembryonic porcine kidney cells. Bactericidal activity was investigated in a liquid digest medium.Fungistatic activity was determined on wort agar. Wheat germs were germinated in Petri dishesaccording to generally accepted methods. The viral titre was calculated by Reed-Muench method.The bacterial titre was determined by seeding the suspensions on agar medium. Statistical processing was performed in Microsoft Office Excel and statsoft STATISTICA 12, using Student's t-test,post-hoc tests: Fisher’s least significant difference test and Duncan’s new multiple range test.Results. It was found that Ni NPs show high virucidal activity against Teschovirus A strainDniprovskyi-34, reducing the virus titre by 2.46 lg TCD50/cm3, and have a chemotherapeutic indexof 4. Ni NPs have low fungistatic activity against Acremonium cucurbitacearum 502, reducing theaverage diameter of colonies by 6.58 to 20.22 %. Regarding Acremonium strictum 048 and Fusarium sp. 072, Ni NPs have a slight stimulating activity, increasing the average diameter of the colonies by 10.18 to 12.44 % and 14.84 to 22.18 %, respectively. Under the action of Ni NPs, the titre ofBacillus subtilis ІМВ В-7023 and Pseudomonas chlororaphis subsp. aureofaciens UKM B-306(2687) upon the cultivation of bacteria in meat-peptone broth significantly (by 80.96 to 82.77 %and 15.67 to 36.39 %, respectively) increases. Ni NPs exhibits growth-promoting properties onwheat germs, increasing the average length of leaf blades and roots by 41.79 and 36.76 %, respectively. Conclusion. According to the study findings, Ni NPs cannot be recommended for the creation of antifungal preparations. Further research is needed to develop Ni NP-based antiviral preparations, virucidal and disinfecting agents, growth- regulating products for cultivated plants, and toincrease the titre of beneficial soil bacteria.

Aim.To use the ability of potato leafroll virus (PLRV) to infect and multiply in mammalian continuous cell lines to purify PLRV isolates from the vegetative plant material, and to study the pathogenicity of those isolates for plants (after culturing in mammalian continuous cell line), to investigate morphological, physical-chemical, biological and antigen properties of PLRV isolates from mammalian cells and to study an alternative diagnostic method -the neutralization test in the mammalian continuous cell lines. Methods. The methods of cultivating animal viruses in the mammalian continuous cell line, microscopical biochemical, and serological methods, the method of arti¿ cial nutrition of aphids are detailed under Material and Methods. Results. It was demonstrated that successful cultivation of PLRV in mammalian continuous cell line allowed obtaining pure virus isolates from potato plants and aphids and preserving them for a long time (over a period of 7 years). The cultivation of PLRV in the mammalian continuous cell line did not impact its pathogenic properties and allowed transmitting the virus to plants. Continuous cells lines of pig embryonic kidney (PEKV), of kidney Syrian hamster (BHK-21), of testicles of piglets (PTP), of kidneys of the bull (MDBC), and of carcinoma rabbit kidney (RK-13) were found to be sensitive to PLRV, Con tinuous cell lines of human (HeLa, Hep-2 and of African green monkey kidney (Vero) were not infected by the virus. The infectious activity of PLRV in the sensitive continuous cell lines was 20-8.5 lg TCD 50 /ml depending on the cell line. The isolates of PLRV were resistant to lipiddissolving solvents, multiplied in a pH range from 4.0 till 10.0 and were thermoresistant at 50 ºɋ in the absence of bivalent ions of magnesium, ɌIP was in the range of 60-65 ºɋ under our experimental conditions. The optimal temperature for the reproduction of PLRV in the cell culture was c. 24 °ɋ. The use of neutralization test in the mammalian continuous cell line allowed isolation in pure culture and identi¿ cation of PLRV reliably in a time span of c. 14 days. Conclusions. It was proven that PLRV can be cultivated in the mammalian continuous cell lines of PEKV, ȼɇɄ-21, PTV, MDȼɄ and RK-13. It was established that the cultivation of PLRV in these continuous cell lines did not impact its biological, pathogenic, antigenic and physical-chemical properties. The identi¿ cation of pure cultures of PLRV obtained in mammalian cells can be reliably performed by the use of neutralization reaction.

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According to the results of the study, the threshold limit values (TLVs) of CeO 2 , and Ce nanoparticles (NPs) for the culture of swine kidney embryonic cell line (SKECL) have been estimated. The TLVs are 0.1 μg/cm 3 for Ce NPs, and 1 μg/cm 3 for CeO 2 NPs. All NPs were non-toxic for white mice at concentration of 2000 mg/kg, which opens up a perspective for the further use of these NPs in the development of antiviral substances. CeO 2 , and Ce NPs have decreased the titer of Teschovirus by 1.46-2 lg 10 TCD 50 / cm 3 at TLVs at all stages of virus reproduction. Sensitivity of the strain Dniprovskyi-34 of species Teschovirus A, serotype Porcine teschovirus 1 (PTV-1), to solvents, proteolytic enzyme trypsin under the presence of CeO 2 , and Ce NPs has been studied. Under the presence of solvents, and trypsin, NPs decreased the infectious titer of the virus slightly by only 0.23 lg 10 TCD 50 /cm 3 . CeO 2 , and Ce NPs have not shown antiviral activity under heating to 50 °C, either with the addition of 1 M solution of MgCl 2 or without it, and did not cause significant decrease of infectious activity of the virus under pH values 2.0, 7.2, and 11.0 within 10 minutes exposition. Ability of CeO 2 , and Ce NPs to interact with viral particles, change their morphology, which can affect infective activity of the virus significantly, has been shown. Addition of CeO 2 , and Ce NPs to the antigen has caused the decrease of the titer of virus-neutralizing antibodies, though it remained high. The results of the studies can be used in development of disinfectants, and antiviral drugs.

If it is necessary to reduce the anthropogenic impact on agroecosystems in conditions of constant increase in the cost of resources – improving the technology of growing corn through the use of nanotechnologies is one of the prerequisites for increasing the yield of crops and their profitability. In this regard, the purpose of the study was to investigate the biological activity of Zn nanocarboxylates and MoS2 nanoparticles at different concentrations for the germination, growth, and development of corn seedlings. An experiment was conducted on corn sprouts to determine the effect of Zn and MoS2 nanoparticles. The germination rate and germination energy of seeds under the action of nanoparticles were determined in accordance with the requirements of the state standard DSTU 4138-2002. The study results were analysed by generally accepted statistical methods. It was established that MoS2 nanoparticles when diluted at 1:10,000 (at a concentration of 700 mcg/l) show biological activity and cause an increase in the length of leaf blades and the length of the roots of corn seedlings by 35.0% and 100.0%, respectively. At other concentrations (1:100; 1:1,000) of Zn and MoS2 nanoparticles, no significant effect on the size of leaf blades and roots was observed. According to the results of the Mana-Whitney test, in all variants, with the exception of the action of MoS2 nanoparticles in a 1:10,000 dilution, the significance level of changes was not sufficient. Only in the variant with MoS2 at 1:10,000 dilution, an increase in root length was statistically significant. There was no statistically significant effect in all the studied variants on the germination energy and laboratory germination of maize seeds. The practical value of the study is to assess the effect of drugs (Zn nanocarboxylates and MoS2 nanoparticles) for foliar top dressing, a wide range of which is offered to agricultural producers, selection of effective concentrations for the growth, development, and yield of corn per grain