Evaluation of Streptomyces saraciticas as Soil Amendments for Controlling Soil-Borne Plant Pathogens

Soil-borne diseases are the major problems in mono cropping. A mixture (designated LTM-m) composed of agricultural wastes and a beneficial microorganism Streptomyces saraceticus SS31 was used as soil amendments to evaluate its efficacy for managing Rhizoctonia solani and root knot nematode (Meloidogyne incognita). In vitro antagonistic assays revealed that SS31 spore suspensions and culture broths effectively suppressed the growth of R. solani, reduced nematode egg hatching, and increased juvenile mortality. Assays using two Petri dishes revealed that LTM-m produced volatile compounds to inhibit the growth of R. solani and cause mortality to the root knot nematode eggs and juveniles. Pot and greenhouse tests showed that application of 0.08% LTM-m could achieve a great reduction of both diseases and significantly increase plant fresh weight. Greenhouse trials revealed that application of LTM-m could change soil properties, including soil pH value, electric conductivity, and soil organic matter. Our results indicate that application of LTM-m bio-organic amendments could effectively manage soil-borne pathogens.

Pochonia chlamydosporia Isolate PC-170-Induced Expression of Marker Genes for Defense Pathways in Tomatoes Challenged by Different Pathogens

Pochonia chlamydosporia is a fungal parasite of nematode eggs. Studies have shown that some strains of Pochonia chlamydosporia can promote plant growth and induce plants’ systemic resistance to root-knot nematodes by colonizing in their roots. This study aimed to verify the effect of the PC-170 strain on tomato growth and systemic resistance. Split-root experiments were conducted to observe the systemic resistance induced by PC-170. To explore the defense pathway that was excited due to the colonization by PC-170, we tested the expression of marker genes for defense pathways, and used mutant lines to verify the role of plant defense pathways. Our results showed that PC-170 can colonize roots, and promotes growth. We found a role for jasmonic acid (JA) in modulating tomato colonization by PC-170. PC-170 can activate tomato defense responses to reduce susceptibility to infection by the root-knot nematode Meloidogyne incognita, and induced resistance to some pathogens in tomatoes. The marker genes of the defense pathway were significantly induced after PC-170 colonization. However, salicylic acid (SA)- and jasmonic acid (JA)-dependent defenses in roots were variable with the invasion of different pathogens. Defense pathways play different roles at different points in time. SA- and JA-dependent defense pathways were shown to cross-communicate. Different phytohormones have been involved in tomato plants’ responses against different pathogens. Our study confirmed that adaptive JA signaling is necessary to regulate PC-170 colonization and induce systemic resistance in tomatoes.

Sanitary condition of soil in the territory of Astrakhan state technical university and nearby territories of higher educational institutions

Objective. The authors of this article studied and analyzed the sanitary condition of the soil in the territory of Astrakhan State Technical University and the nearby territories of higher educational institutions. Materials and methods. The study was carried out in May June 2019 on the basis of the laboratory of the Department of Infectious Diseases and Epidemiology of Astrakhan State Medical University and the laboratory of the Department of Applied Biology and Microbiology of Astrakhan State Technical University. Thirty soil samples were taken from these territories. The studies of soil samples for parasitological indicators were performed according to the guidelines "Control Methods. Biological and Microbiological Factors. Methods of Sanitary and Parasitological Research", for microbiological indicators "Methods of Soil Microbiological Control". Results. The following results were obtained: the sanitary-parasitological condition of the soil in parks near higher educational institutions in Astrakhan remains very tense as evidenced by positive findings of geohelminthoses; when assessing the degree of epidemic hazard of soil, there were identified nematode eggs and adult worm Strongyloids, that corresponds to the indicators of moderately hazard soil; the presence of live strongylid larvae in the studied samples indicates contamination of the soil with feces of infested animals, and the presence of Ascaris eggs indicates contamination of the soil with sewage or feces of infested children walking and resting in these territories; the total microbial number on average gave indicators for evaluating the selected soil samples as a slightly polluted soil. Conclusions. The sanitary and parasitological state of soil in parks of Astrakhan higher educational institutions remains rather tense as evidenced by positive findings of geohelminthoses.

A Facile and Modified Scheme for Synchronization and Isolation of Nematode Eggs

Nematodes are common pests that damage agricultural crop plants. Some of them are beneficial while others are parasitic and harmful to plants, animals and humans. Several in vitro studies have aimed to develop chemicals to kill parasitic nematodes, while others have been conducted to use beneficial nematodes as biocontrol agents. However, the preparation of large quantities of nematode eggs in a laboratory setting is challenging. Traditional egg isolation protocols involve the use of sieves to filter eggs or the use of chemicals that can be harmful to nematodes while isolating the eggs. Our method utilizes 1.5 × 1.5 cm sized chunks of bacterial or fungal feed to lure nematodes. A subsequent gentle washing of the consumed chunk with distilled water provides a rapid and straightforward method of collecting eggs in 6-well polystyrene plates and removing unwanted nematodes. Approximately 4000 Bursaphelenchus xylophilus eggs from a fungal chunk and 2400 Caenorhabditis elegans eggs from a bacterial chunk were obtained when tested. This study shows a protocol for the isolation of eggs and synchronization of nematode stages that is relatively straightforward, rapid, eco-friendly, and efficient. The protocol also provides a chemical-free and a reliable, simple means of separating eggs from adults and induces the synchronization of nematodes based on the simple concept that gravid nematodes can be provoked to lay eggs by providing additional feed.

Mini-FLOTAC and McMaster egg counting method for detection of gastrointestinal parasites in small ruminants: a comparison study

The proper diagnosis of gastrointestinal parasites of small ruminants requires the development of multivalent techniques characterized by high sensitivity, specificity, precision, reproducibility, and the ability to quickly detect and monitor infections that pose risks to animal health. The aim of this study was to evaluate the performance of Mini-FLOTAC technique and McMaster egg counting (gold standard) in the detection of gastrointestinal parasites of goats and sheep. A total of 789 fecal samples were analyzed (401 of sheep and 388 of goats). From those, nematode eggs were detected in 80.86% (638/789), being 72.57% (291/401) from sheep and 89.43% (347/388) from goats. The Mini-FLOTAC technique presented a better performance to detect helminth eggs in both goats (88.40%; 343/388) and sheep (71.57%; 287/401) (?2 = 10.358; p < 0.0001). Kappa analysis revealed a weak concordance between techniques for goats (k = 0.342; p < 0.001) and sheep (k = 0.281; p < 0.001). Data herein reported suggests that the Mini-FLOTAC is a technique more sensitive than the McMaster egg counting, therefore its use might be adopted for the diagnosis of gastrointestinal infection in small ruminants.

Excretion of Histomonas meleagridis following experimental co-infection of distinct chicken lines with Heterakis gallinarum and Ascaridia galli

Background Histomonosis is a severe re-emerging disease of poultry caused by Histomonas meleagridis, a protozoan parasite which survives in the environment via the cecal worm Heterakis gallinarum. Following infection, the parasites reside in the ceca and are excreted via host feces. In the present work, male birds of conventional broiler (Ross 308, R), layer (Lohmann Brown Plus, LB) and a dual-purpose (Lohmann Dual, LD) chicken line were infected with 250 embryonated eggs of Ascaridia galli and Heterakis gallinarum, respectively, with the latter nematode harboring Histomonas meleagridis, to investigate a co-infection of nematodes with the protozoan parasite in different host lines. Methods In weekly intervals, from 2 to 9 weeks post infection (wpi), individual fecal samples (n = 234) from the chickens were collected to quantify the excretion of H. meleagridis by real-time PCR and to determine the number of nematode eggs per gram (EPG) in order to elucidate excretion dynamics of the flagellate and the nematodes. This was further investigated by indirect detection using plasma samples of the birds to detect antibodies specific for H. meleagridis and worms by ELISA. The infection with H. meleagridis was confirmed by histopathology and immunohistochemistry to detect the flagellate in the cecum of representing birds. Results The excretion of H. meleagridis could already be observed from the 2nd wpi in some birds and increased to 100% in the last week of the experiment in all groups independent of the genetic line. This increase could be confirmed by ELISA, even though the number of excreted H. meleagridis per bird was generally low. Overall, histomonads were detected in 60% to 78% of birds with temporary differences between the different genetic lines, which also showed variations in the EPG and worm burden of both nematodes. Conclusions The infection with H. gallinarum eggs contaminated with H. meleagridis led to a permanent excretion of the flagellate in host feces. Differences in the excretion of H. meleagridis in the feces of genetically different host lines occurred intermittently. The excretion of the protozoan or its vector H. gallinarum was mostly exclusive, showing a negative interaction between the two parasites in the same host. Graphic abstract

EFFICIENCY OF THE PREPARATION OF THE PROLONGED ACTION ON THE BASIS OF MOXIDECTIN "NEOTERICA PROTECTO SYRUP" IN ECTOAND ENDOPARASITOSIS OF CARNIVORE ANIMALS

This article presents the results of studies of the therapeutic and prophylactic efficacy of the drug "Neoterica Protecto Syrup" for arachnoentomoses and nematodes of domestic carnivores. The drug contains the active ingredient moxidectin, which provides a wide range of antiparasitic action of the drug against ecto- and endoparasites. The studies were conducted from April to August 2020 in veterinary clinics in Moscow and the Moscow region on dogs and cats free from parasites and naturally infested with fleas, lice, ixodid and scabies mites, intestinal nematodes and dirofilaria larvae. The animals were administered the drug once orally individually at a therapeutic dose at the rate of 1.5 mg moxidectin per 1 kg of animal weight. The diagnosis and efficacy of the diseases were confirmed by clinical (examination of the skin and hair for the presence of ectoparasites) and laboratory (Priselkova's method for detecting acariform mites in scrapings, the "thick crushed drop method" for detecting dirofilariae, Fülleborn's method for detecting nematode eggs) studies have confirmed the therapeutic efficacy the drug, the antiparasitic activity persisted for 90 days after application, which confirms the preventive effectiveness of the drug.