Paramecium Caudatum Research Articles

Cd indirectly affects the structure and function of plankton ecosystems by affecting trophic interactions at environmental concentrations

The toxic effects of potentially toxic elements have been observed at low concentrations; however, many studies have focused on single-species toxicity testing. Consequently, it is imperative to quantify toxicity at the community level at environmental concentrations. A microcosm approach was employed in conjunction with the Lotka-Volterra model to ascertain the impact of environmentally relevant concentrations of cadmium (Cd) on plankton abundance, community function, and stability. The results demonstrated that Cd led to a reduction in the abundance of Daphnia magna, yet unexpectedly resulted in an increase in the abundance of Brachionus calyciflorus and Paramecium caudatum. Additionally, Cd was observed to impede primary productivity, metabolic capacity and the stability of the planktonic community. Further model analyses revealed that the environmental concentration of Cd directly reduced intrinsic growth rates and intraspecific interactions. In particular, we found that the predation effects of Daphnia magna on Brachionus calyciflorus were significantly weakened. The findings of this study offer quantitative evidence that Cd exposure exerts an indirect influence on the structure and functioning of plankton ecosystems, mediated by alterations in trophic interactions. The findings indicate that the impact of environmental concentrations of potentially toxic elements may be underestimated in single-species experiments.

Parasite Contamination of Water Source at Pangkalan Masyhur Sub-district, Medan Johor District

According to World Health Organisation (WHO) estimates, at least 1,8 billion people consume contaminated water worldwide, hence most of the diarrheal disease in the world is attributable to unsafe water, and the lack of sanitation and hygiene. Water utilization by humans and animals can generate biological pollutants which may contaminate the water. These contaminants come from waste products that may contain bacteria, protozoa, and other parasites. This was a descriptive study with cross sectional design and simple random sampling to determine the contamination of water source by pathogens, particularly parasites at Region V Pangkalan Masyhur sub-district, Medan Johor district, Medan, North Sumatera in 2012. Samples were obtained from each house, depending on the main water source used, either from tap water, open wells, or the nearby river streams. Modified Caldwell’s sedimentation technique was applied to examine the samples under light microscope. Out of the 103 water samples collected, most were from tap water (78 samples), followed by open wells (19 samples), and only six were from the nearby river streams. We found Paramecium caudatum from nine samples (8,7%) collected from the open wells and the nearby river streams, followed by hookworm larva in one tap water sample (1%). No protozoa such as Entamoeba spp., Cryptosporidium spp., and Giardia spp. found in any of the samples. Based on this data, the abundant presence of P.caudatum represented the condition of high organic debris in the open wells and the nearby river streams. Additionally, the presence of hookworm larva in the tap water indicated the distribution system was contaminated with the surrounding soil. Hence it is imperative to provide counseling about optimal environmental sanitation and clean water management, including proper maintenance for water source and its distribution system. Tap water distribution, including its network of pipe deliverance system, must be checked and maintained regularly.

Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

Abstract Predator and prey traits are important determinants of the outcomes of trophic interactions. In turn, the outcomes of trophic interactions shape predator and prey trait evolution. How species' traits respond to selection from trophic interactions depends crucially on whether and how heritable species' traits are and their genetic correlations. Of the many traits influencing the outcomes of trophic interactions, body size and movement traits have emerged as key traits. Yet, how these traits shape and are shaped by trophic interactions is unclear, as few studies have simultaneously measured the impacts of these traits on the outcomes of trophic interactions, their heritability, and their correlations within the same system. We used outcrossed lines of the ciliate protist Paramecium caudatum from natural populations to examine variation in morphology and movement behaviour, the heritability of that variation, and its effects on Paramecium susceptibility to predation by the copepod Macrocyclops albidus. We found that the Paramecium lines exhibited heritable variation in body size and movement traits. In contrast to expectations from allometric relationships, body size and movement speed showed little covariance among clonal lines. The proportion of Paramecium consumed by copepods was positively associated with Paramecium body size and velocity but with an interaction such that greater velocities led to greater predation risk for large body‐sized paramecia but did not alter predation risk for smaller paramecia. The proportion of paramecia consumed was not related to copepod body size. These patterns of predation risk and heritable trait variation in paramecia suggest that copepod predation may act as a selective force operating independently on movement and body size and generating the strongest selection against large, high‐velocity paramecia. Our results illustrate how ecology and genetics can shape potential natural selection on prey traits through the outcomes of trophic interactions. Further simultaneous measures of predation outcomes, traits, and their quantitative genetics will provide insights into the evolutionary ecology of species interactions and their eco‐evolutionary consequences. Read the free Plain Language Summary for this article on the Journal blog.

Transfer from ciliate to zebrafish: Unveiling mechanisms and combined effects of microplastics and heavy metals

The impacts and toxicological mechanisms of microplastics (MPs) or heavy metals on aquatic ecosystems have been the subject of extensive research and initial understanding. However, the combined toxicity of co-pollutants on organisms and cumulative toxic effects along the food chain are still underexplored. In this study, the ciliate protozoan Paramecium caudatum and zebrafish Danio rerio were used to represent the microbial loop and the higher trophic level, respectively, to illustrate the progressive exposure of MPs and cadmium (Cd2+). The findings indicate that MPs (ca. 1 ×105 items/L) containing with Cd2+ (below 0.1 µg/L) could permeate the bodies of zebrafish through trophic levels after primary ingestion by ciliates. This could cause adverse effects on zebrafish, including alterations in bioindicators (total sugar, triglycerides, lactate, and glycogen) associated with metabolism, delayed hepatic development, disruption of intestinal microbiota, DNA damage, inflammatory responses, and abnormal cellular apoptosis. In addition, the potential risks associated with the transfer of composite pollutants through the microbial loop into traditional food chain were examined, offering novel insights on the evaluation of the ecological risks associated with MPs. As observed, understanding the bioaccumulation and toxic effects of combined pollutants in zebrafish holds crucial implications for food safety and human health.

Utilizing Zebrafish Embryos for Replication of Tulane Virus: A Human Norovirus Surrogate

The zebrafish larvae/embryo model has been shown to support the replication of seven strains (G1.7[P7], GII.2[P16], GII.3[P16], GII.4[P4], GII.4[P16], GII.6[P7], and GII.17[P13]) of human norovirus (HuNoV). However, due to challenges in consistently obtaining HuNoV-positive stool samples from clinical sources, evaluating HuNoV surrogates in this model is highly valuable. This study assesses the potential of zebrafish embryos and larvae as a model for Tulane virus (TuV) replication. Three infection methods were examined: microinjection, immersion, and feeding. Droplet digital PCR was used to quantify viral RNA across all three infection methods. Microinjection of 3 nL of TuV into zebrafish embryos (< 6-h post-fertilization) resulted in significant replication, with viral RNA levels reaching 6.22 logs at 4-day post-infection. In contrast, the immersion method showed no replication after immersing 4-day post-fertilization (dpf) larvae in TuV suspension for 6 h. Similarly, no replication was observed with the feeding method, where Paramecium caudatum loaded with TuV were fed to 4 dpf larvae. The findings indicate that the zebrafish embryo model supports TuV replication through the microinjection method, suggesting that TuV may serve as a useful surrogate for studying HuNoV pathogenesis. Additionally, TuV can be utilized in place of HuNoV in method optimization studies using the zebrafish embryo model, circumventing the limited availability of HuNoV.

Inter-turn intervals in Paramecium caudatum display an exponential distribution

ABSTRACT In navigating to a better location, mobile organisms in diverse taxa change directions of travel occasionally, including bacteria, archaea, single-celled eukaryotes, and small nematode worms such as Caenorhabditis elegans. In perhaps the most common form of goal-orientated movement, the rate of such turns is adjusted in all these taxa to ascend (or descend) a chemical gradient. Basically, the rate of turns is reduced when the movement results in better conditions. In the bacterium Escherichia coli and in C. elegans, the turns are generated by random-rate processes, in which the probability of a turn occurring is constant at every moment. This is evidenced by a distribution of inter-turn intervals that has an exponential distribution. For the first time, we examined the distribution of inter-turn intervals in the single-celled eukaryote, Paramecium caudatum, in a class exercise for first-year university students. We found clear evidence for an exponential distribution of inter-turn intervals, implying a random-rate process in generating turns in Paramecium. The exercise also shows that university laboratory classes can be used to generate scientific data to address research questions whose answers are as yet unknown.

Influence of dissolved oxygen in the environment on toxicity indices obtained by various bio-testing methods

RELEVANCE of the study comes from the understanding of the necessity of continuous development of toxicological analysis. Since The simplest organisms are used in toxicological analysis as bioindicators, the reactions of which to the presence of certain pollutants will always differ, the only way to assess the usefulness of a bioindicators as a tool is to study its behavior under specific tasks. Biondicators differ in their metabolic properties, in particular, in the ways of obtaining energy from the presence of molecular oxygen in the environment. However, it is assumed that the presence of different concentrations of oxygen in the environment affects the behavior of the simplest organisms, which, in its turn, can affect the results of toxicological analysis. Previously, this effect has not been studied. THE PURPOSE. The research of the effect of dissolved oxygen on toxicity indices obtained using of bacteria Escherichia coli (Migula) Castellani and Chalmers and ciliates Paramecium caudatum Ehrenberg, METHODS. Obtaining indices of toxicity is given with different concentrations of dissolved oxygen in the environment, which are distilled water and Bonaqua brand water, by the bioluminescent reaction of bacteria and chemotactic reaction of ciliates. RESULTS. With an increase in the concentration of dissolved oxygen in the environment, the bioluminescence of bacteria increases, therefore, the toxicity index decreases. No effect on ciliates is observed. CONCLUSION. It can be concluded that dissolved oxygen does not affect the biotest analysis using ciliates. When using bacteria as a test organism, an error occurs in the toxicity index.

Size dependent uptake and trophic transfer of polystyrene microplastics in unicellular freshwater eukaryotes

Microplastics (MP) have become a well-known and widely investigated environmental pollutant. Despite the huge amount of new studies investigating the potential threat posed by MP, the possible uptake and trophic transfer in lower trophic levels of freshwater ecosystems remains understudied. This study aims to investigate the internalization and potential trophic transfer of fluorescent polystyrene (PS) beads (0.5 μm, 3.6 × 108 particles/mL; 6 μm, 2.1 × 105 particles/mL) and fragments (<30 μm, 5 × 103 particles/mL) in three unicellular eukaryotes. This study focuses on the size-dependent uptake of MP by two freshwater Ciliophora, Tetrahymena pyriformis, Paramecium caudatum and one Amoebozoa, Amoeba proteus, serving also as predator for experiments on potential trophic transfer. Size-dependent uptake of MP in all three unicellular eukaryotes was shown. P. caudatum is able to take up MP fragments up to 27.7 μm, while T. pyriformis ingests particles up to 10 μm. In A. proteus, small MP (PS0.5μm and PS6μm) were taken up via pinocytosis and were detected in the cytoplasm for up to 14 days after exposure. Large PS-MP (PS<30μm) were detected in A. proteus only after predation on MP-fed Ciliophora. These results indicate that A. proteus ingests larger MP via predation on Ciliophora (PS<30μm), which would not be taken up otherwise. This study shows trophic transfer of MP at the base of the aquatic food web and serves as basis to study the impact of MP in freshwater ecosystems.

Identification and Characterization of the Gene Responsible for the O3 Mating Type Substance in Paramecium caudatum.

The process of sexual reproduction in eukaryotes starts when gametes from two different sexes encounter each other. Paramecium, a unicellular eukaryote, undergoes conjugation and uses a gametic nucleus to enter the sexual reproductive process. The molecules responsible for recognizing mating partners, hypothetically called mating-type substances, are still unclear. We have identified an O3-type mating substance polypeptide and its gene sequence using protein chemistry, molecular genetics, immunofluorescence, RNA interference, and microinjection. The O3-type substance is a polypeptide found in the ciliary membranes, located from the head to the ventral side of cells. The O3-type substance has a kinase-like domain in its N-terminal part located outside the cell and four EF-hand motifs that bind calcium ions in its C-terminal part located inside the cell. RNA interference and immunofluorescence revealed that this polypeptide positively correlated with the expression of mating reactivity. Microinjection of an expression vector incorporating the O3Pc-MSP gene (Oms3) induced additional O3 mating type in the recipient clones of different mating types or syngen. Phylogenetic analysis indicates that this gene is widely present in eukaryotes and exhibits high homology among closely related species. The O3Pc-MSP (Oms3) gene had nine silent mutations compared to the complementary mating type of the E3 homologue gene.

Toxicity evaluation of a strain isolated from pollack digestive tract using Paramecium caudatum

A strain was isolated from the digestive organs of Walleye pollack residing in the East Sea of the DPR Korea, which not only produces cryophilic protease, organic acid but also has intestinal adhesion property and bacteriostatic activity against pathogens. The strain was classified and identified as Pseudomonas fragi by genetic system classification methods and registered as KCCC 10110 at the Korean Centre for Culture Collection (KCCC) of the State Academy of Sciences, DPR KOREA. In vivo and in vitro toxicity of Pseudomonas fragi KCCC 10110 was evaluated using Paramecium caudatum. In the treatments with P. fragi KCCC 10110, Bacillus subtilis KCCC 11214 and Lactobacillus lactis KCCC 13208, all of these being well known as non-toxic and probiotic for animals and fishes, higher microbial counts and normal movement of P.caudatum were observed while significant lower cell numbers and abnormal movement of P.caudatum were shown in the treatments with pathogenic strains Clostridium tetani 473, Salmonella typhosa 901 and Aeromonas punctata 823. These results suggest that probiotic and pathogenic bacteria have different influence on Paramecium caudatum and that the strain isolated from Walleye pollack digestive tract is non-toxic.

Application of RNA interference and protein localization to investigate housekeeping and developmentally regulated genes in the emerging model protozoan Paramecium caudatum

Unicellular eukaryotes represent tremendous evolutionary diversity. However, the molecular mechanisms underlying this diversity remain largely unexplored, partly due to a limitation of genetic tools to only a few model species. Paramecium caudatum is a well-known unicellular eukaryote with an unexpectedly large germline genome, of which only two percent is retained in the somatic genome following sexual processes, revealing extensive DNA elimination. However, further progress in understanding the molecular mechanisms governing this process is hampered by a lack of suitable genetic tools. Here, we report the successful application of gene knockdown and protein localization methods to interrogate the function of both housekeeping and developmentally regulated genes in P. caudatum. Using these methods, we achieved the expected phenotypes upon RNAi by feeding, and determined the localization of these proteins by microinjection of fusion constructs containing fluorescent protein or antibody tags. Lastly, we used these methods to reveal that P. caudatum PiggyMac, a domesticated piggyBac transposase, is essential for sexual development, and is likely to be an active transposase directly involved in DNA cleavage. The application of these methods lays the groundwork for future studies of gene function in P. caudatum and can be used to answer important biological questions in the future.

Intensification of the production of a plant-based probiotic drink

The quality of the finished probiotic drink is closely related to the completeness and intensity of the fermentation process of lactic acid bacteria in the plant environment of the drink. As part of our research, ways to intensify the fermentation process are proposed due to the additional introduction of vegetable protein and curcumin into the oat drink. The activity of the fermentation process was assessed by the accumulation of biomass, the results of the titrated acidity assessment, the antioxidant properties of probiotic drinks, and the number of probiotic microorganisms. The research results showed that the introduction of additional vegetable protein and curcumin activates the accumulation of microbial biomass by an average of 15-85%, lactic acid – by 40-69% and 5.9 – 12%, respectively, increases antioxidant activity by an average of 2.2 – 6.7%, the increase in protozoan Paramecium Caudatum is when introduced into protein samples – 71.8-74.4%, curcumin – 3.1-22.8%. Thus, it was found that an additional increase in the protein component of the nutrient medium of a vegetable drink and the introduction of curcumin have a stimulating effect on biotechnological processes and are promising in the production of probiotic drinks.

Identification of toxin-producing cyanobacteria in water reservoirs of Kirov region and assessment of their relationship with water toxicity to hydrobionts

Molecular genetic methods of analysis were used for the first time detection of cyanotoxin biosynthesis genes (microcystin, cylindrospermopsin, anatoxin-a, and saxitoxins) in organisms inhabiting the two largest water reservoirs of Kirov region (Belokholunitsky and Omutninsky) located in the northeast of the Russian Plain in the southern taiga subzone. The mcyE gene responsible for microcystin production was detected in all phytoplankton samples, and the anaC gene responsible for anatoxin-a production was detected in the most samples. 14 cyanobacteria taxa were found in the phytoplankton of the studied reservoirs. Microcystis and Dolichospermum are the most probable microcystin producers. The most probable anatoxin-a producers in Belokholunitsky reservoir are Aphanizomenon flos-aquae and Dolichospermum planctonicum, and in Omutninsky reservoir – Cuspidothrix issatschenkoi and Dolichospermum flos-aquae. Water from the studied reservoirs had an acute toxic effect on luminescent bacteria Escherichia coli (“Ecolum” test system) and protozoa Paramecium caudatum Ehrenberg, but was non-toxic to Entomostracans Daphnia magna Straus.

STUDIES ON THE TOXICITY OF C-PHYCOCYANIN IN GUPPY FISH AND INFUSORIA PARAMECIUM CAUDATUM

One of the important and urgent tasks, whose successful solution depends on the supply of food to the population, is to increase the production of livestock products. Ensuring a high level of production of livestock products largely depends on the quality of feed, which is determined, first of all, by toxicological control.&#x0D; C-phycocyanin is a protein complex that belongs to phycobiliproteins and can be used as one of the potential natural components to improve the feeding of commercial fish.&#x0D; In order to establish the safety of the use of active feed components for feeding and ready-made feed into which these components are introduced, first of all, it is necessary to study their effect on the organisms of protozoa and fish, which are used for laboratory research.&#x0D; The high sensitivity of ciliates to the appearance of toxic substances in their environment and changes in their concentration led to the use of these organisms for testing the most diverse chemical elements and compounds.&#x0D; The article presents the results of studying the effect (harmlessness) of C-phycocyanin on the bodies of protozoa (Paramecium caudatum) and guppy fish.&#x0D; When studying the effect of C-phycocyanin on the body of protozoa (Paramecium caudatum), it was established that its use for 48 hours in doses of 5, 10, 25, 50, and 100 mg/l did not cause the death of ciliates. When studying the effect of C-phycocyanin on the body of guppy fish, it was established that its use in doses of 5, 10, 25, 50, and 100 mg/l did not cause the death of fish.&#x0D; So, on the basis of the conducted research, it was established that C-phycocyanin belongs to class 4, and is a non-toxic substance for Paramecium caudatum ciliates. In addition, it was established that its use in the above doses did not cause the death of fish, and its LC50 is higher than 100 mg/l.

Growth and Survival of Philippine Endemic Juvenile Silver Therapon (Leiopotherapon plumbeus) Fed with Different Natural Live Feeds

Aquaculture of the endemic silver therapon (Leiopotherapon plumbeus) in Laguna de Bay is now seen as valuable instrument to improve its diminished stock and fisheries. Its dietary preferences during its early life stages are not yet well understood leading to low survival. Hence, the present study examined the effect of different natural live feeds namely, Panagrellus redivivus, Moina macrocopa, Artemia franciscana nauplii, and Paramecium caudatum, on the survival and growth of juvenile silver therapon after 30 days of feeding trials. Panagrellus fed silver therapon juveniles have better survival (97.85%, p&lt;0.05), followed by Artemia (54.37%), Moina (45.26%) and Paramecium (40.67%). For growth, a Panagrellus diet also resulted to significantly higher (p&lt;0.05) mean values for all parameters: weight gain (259.50 mg), length gain (13.40 mm), specific growth rate (5.60%), absolute growth (8.65 mg) and relative growth rate (5.08). Differences in the effects of different live feeds on the survival and growth of L. plumbeus juveniles may be at tributed to their different nutritional composition, with Panagrellus having better total crude protein and fat content, and amino acid and fatty acid composition, which are important in the overall metabolism, growth, development, and survival of fish. The present study demonstrates that provision of Panagrellus to L. plumbeus juveniles will result in significantly better survival and growth.

Comparative Analysis of Taylor Series and Runge-Kutta Fehlberg Methods in Solving the Lotka-Volterra Competitive Model

This paper primarily scrutinizes the comparative efficacy of numerical methods, namely the Taylor Series and the Runge-Kutta Fehlberg methods, against the exact solution in solving mathematical models. These methods exhibit the capacity to handle the non-linearity of the Lotka-Volterra competitive model with a high degree of accuracy and reliability. The comparison of results obtained from both methods and the exact solution shows that the Runge-Kutta Fehlberg method provides a more precise approximation for the model than the Taylor Series method. This conclusion is supported by computations carried out using the Mathematica 13.2 software. The research data involves two species, Paramecium Caudatum and Stylonychia Pustulata, derived from Gause's experiment. Both species demonstrate an intraspecific interaction, with their populations rising steadily until reaching a constant level. For Paramecium Caudatum, the population peaks at 202 cells on the 16th day, while for Stylonychia Pustulata, it reaches a maximum of 41 cells on the 8th day. Equilibrium and stability analysis offer vital insights into the long-term behavior of the system and its reaction to perturbations. In mixed populations, when the carrying capacity of both species is less than the carrying capacity of another species divided by the competition coefficient, the species coexist in a stable equilibrium. Conversely, if the carrying capacity of one species is less than the carrying capacity of the other divided by the competition coefficient, one species may outcompete the other, leading to an unstable equilibrium or even extinction of the weaker species. The research thus provides valuable insights into the dynamics of competition and survival, with profound implications for the fields of ecology, conservation, and environmental management.

Luminescent Media Based on Heteroligand Lanthanide Complexes and Lyotropic Mesophases for Bioimaging Application

New terbium and europium heteroligand complexes with substituted 1,2,3-triazole – bis-1,3-(4-methylcarboxyl-1,2,3-triazol-1-yl)xylylene have been synthesized. A study of luminescent properties showed that the complexes exhibit high optical characteristics. The luminescence efficiency of [Tb(AcAc)2(TR)(H2O)2], increases by 13 % compared to the monoligand complex [Tb(AcAc)3(H2O)2]. In order to create biocompatible systems, an approach for the solubilization of hydrophobic complexes by incorporating them into the lyomesophase structure of P123/DMSO has been developed. According to polarization optical microscopy, the hybrid system containing 0.2 % of the [Tb(AcAc)3(H2O)2] complex shows a lamellar mesophase. Fluorescence microscopy study showed that the [Eu(TTA)2(TR)(H2O)2] complex is efficiently adsorbed on the surface of the Paramecium caudatum microorganism and exhibits red luminescence allowing visualization of biological objects.

ENVIRONMENTAL IMPACT AND SAFETY OF AGROPROTECTIVE CHEMICAL BASED ON THIAMETHOXAM

The article is devoted to the aspects of environmental safety of the use of Aktara insecticide, widely used in the agro-protective sector, with the active substance thiamethoxam from the class of neonicotinoids. Studies have been carried out on the impact of insecticide on test organisms of soil and aquatic ecosystems, and its transformation in the process of laboratory biodegradation has been studied on the basis of chromato-mass-spectral analysis.&#x0D; In order to identify the anthropogenic load of soil and water ecosystems during the application of the Aktara preparation containing thiamethoxam, and to assess the toxicity of the insecticide, test objects were studied: earthworms (Lumbricus terrestris L.), shoe ciliates (Paramecium caudatum). The phytotoxicity of the drug was analyzed using test objects - seeds: corn (Zea mays), pea (Pisum sativum), tomato (Solanum lycopersicum), cucumber (Cucumis sativus), carrot (Daucus carota) and cabbage (Brassica oleracea), it was evaluated germination state. The biodegradation of thiamethoxam with the help of soil degrading microorganisms was studied.&#x0D; The material for the experiments was Aktara, in which the active ingredient is thiamethoxam. Fertile chernozem, selected from the ecologically clean territory of the Iglinsky district of the Republic of Bashkortostan.&#x0D; In the presented work, experiments were carried out on the effect of the drug on earthworms (Lumbricus terrestris L.), taking into account their behavior, the condition of contact of the test object with the insecticide was modeled.&#x0D; Studies on phytotoxicity were carried out, vegetables (cucumber, carrot, tomato, cabbage), cereals (corn) and legumes (peas) were used as test objects.&#x0D; Biotesting on infusoria-shoes (Paramecium caudatum) was carried out by an experimental method using the 2M-BIOTESTER device. Obtaining destructive material - microorganisms-destructors was carried out by the method of «imprints» in Petri dishes on meat-peptone agar, isolating them from fertile chernozem, selected in the Iglinsky district of Bashkortostan.&#x0D; The change in the destructive material of the active substance of the insecticide was determined using a thin layer chromatogram (TLC), Silufol UV-254 plates were used, the eluent was acetone, the developer was phosphomolybdic acid. Chromato-mass-spectral analysis was performed on a Shimadzu GC-9A instrument.&#x0D; The results of the analysis of the effect of the insecticide based on thiamethoxam on earthworms showed that this substance has a moderately toxic effect.&#x0D; In uncontaminated soil, in microbiota-rich chernozem, a large species spectrum and numerical composition of microorganisms were observed: Pseudomonas sp., Bacillus sp., Arthrobacter sp., Azotobacter sp., Flavobacterium sp. The introduction of an insecticide (IC) into the agrosystem leads to a decrease in biomass, inhibition of the microbiota, and a negative impact is noted at the working concentration declared by the manufacturer. When using a dose of insecticide 2 IC in the soil, a further decrease in biomass was recorded and species resistant to toxicity were Pseudomonas sp. and Bacillus sp. With significant soil contamination, at a dose of insecticide 5 IC, the growth of the microenvironment was suppressed.&#x0D; Biodegradation of thiamethoxam – [5-methyl-3-(2-chlorothiazol-5-ylmethyl)-1,3,5-oxadiazinan-4-ylidene-N-nitroamine], C8H10NO3SCl – was carried out for 170 days.&#x0D; According to the results of chromato-mass spectral analysis, intermediate products of biodegradation were determined – bis (2-methylpropyl) ester of 1,2-benzenedicarboxylic acid, diisooctyl adipate.&#x0D; In experiments on the study of phytotoxicity after treatment with the Aktara preparation of various concentrations: IC, 2 IC, 5 IC, the analysis showed a different result in comparison with the control sample.&#x0D; It has been established that at the right concentration, thiamethoxam can have a positive effect on seed germination. Therefore, thiamethoxam is not toxic to plants if the instructions are followed.&#x0D; The results of biotesting revealed that the toxicity index of samples with IC preparation and 2 IC corresponds to a moderate degree of toxicity (0,565 and 0,671, respectively) and 5 IC (0,797) corresponds to a high degree of toxicity.

Phenotypic response to different predator strategies can be mediated by temperature.

Temperature change affects biological systems in multifaceted ways, including the alteration of species interaction strengths, with implications for the stability of populations and communities. Temperature-dependent changes to antipredatory responses are an emerging mechanism of destabilization and thus there is a need to understand how prey species respond to predation pressures in the face of changing temperatures. Here, using ciliate protozoans, we assess whether temperature can alter the strength of phenotypic antipredator responses in a prey species and whether this relationship depends on the predator's hunting behavior. We exposed populations of the ciliate Paramecium caudatum to either (i) a sit-and-wait generalist predator (Homalozoon vermiculare) or (ii) a specialized active swimmer predator (Didinium nasutum) across two different temperature regimes (15 and 25°C) to quantify the temperature dependence of antipredator responses over a 24-h period. We utilized a novel high-throughput automated robotic monitoring system to track changes in the behavior (swimming speed) and morphology (cell size) of P. caudatum at frequencies and resolutions previously unachievable by manual sampling. The change in swimming speed through the 24 h differed between the two temperatures but was not altered by the presence of the predators. In contrast, P. caudatum showed a substantial temperature-dependent morphological response to the presence of D. nasutum (but not H. vermiculare), changing cell shape toward a more elongated morph at 15°C (but not at 25°C). Our findings suggest that temperature can have strong effects on prey morphological responses to predator presence, but that this response is potentially dependent on the predator's feeding strategy. This suggests that greater consideration of synergistic antipredator behavioral and physiological responses is required in species and communities subject to environmental changes.

Material-engineered bioartificial microorganisms enabling efficient scavenging of waterborne viruses

Material-based tactics have attracted extensive attention in driving the functional evolution of organisms. In aiming to design steerable bioartificial organisms to scavenge pathogenic waterborne viruses, we engineer Paramecium caudatum (Para), single-celled microorganisms, with a semiartificial and specific virus-scavenging organelle (VSO). Fe3O4 magnetic nanoparticles modified with a virus-capture antibody (MNPs@Ab) are integrated into the vacuoles of Para during feeding to produce VSOs, which persist inside Para without impairing their swimming ability. Compared with natural Para, which has no capture specificity and shows inefficient inactivation, the VSO-engineered Para (E-Para) specifically gathers waterborne viruses and confines them inside the VSOs, where the captured viruses are completely deactivated because the peroxidase-like nano-Fe3O4 produces virus-killing hydroxyl radicals (•OH) within acidic environment of VSO. After treatment, magnetized E-Para is readily recycled and reused, avoiding further contamination. Materials-based artificial organelles convert natural Para into a living virus scavenger, facilitating waterborne virus clearance without extra energy consumption.