[Activity of detoxifying and antioxidant enzymes in the pond snail Lymnaea stagnalis (gastropoda: pulmonata) during invasion by trematode cercariae].

A comparative analysis of changes of activities of detoxifying and antioxidant enzymes was carried out in the body homogenate of the pond snail Lymnaea stagnalis. Juvenile snails with the shell size of 4-6 mm were infested with cercariae of one (Echinoparyphium aconiatum or E. recurvatum or Moliniella anceps) or two (E. aconiatum +M. anceps or E. aconiatum + E. recurvatum or E. recurvatum + M. anceps) trematode species. It has been revealed that activities of detoxifying and antioxidant enzymes in the body of the snail L. stagnalis change at invasion with trematodes and that the character of the changes depends on the stage of development of the trematodes in the host body, the variant of infestation (monoinvasion or mixed infestation), and the species of the parasite. The first 2 h after penetration of the trematode cercariae into the molluse tissues is accompanied by an increase of activities of the detoxifying and antioxidant enzymes. A long coexistence of metacercariae in the host body (no less than for 13 days) is accompanied by a decrease of activities of non-specific esterases and glutathione-S-transferase and by an increase of superoxide dismutase.

[Generation of reactive oxygen species and activity of antioxidants in larva hemolymph of galleria mellonella (L.) (lepidoptera: piralidae) at development of process of encapsulation].

Activities of enzymatic antioxidants (superoxide dismutase, glutathione-S-transferase, and catalase) have been determined in hemocytes and generation of reactive oxygen species (ROS) has been studied in lymph of larvae of the wax moth Galleria mellonella at development of the process of encapsulation of nylon implants. It has been established that as soon as 15 min after piercing of cuticle with implant the capsule is formed on its surface. The active melanization of the capsule has been shown to last for 4 h. There have been shown a statistically significant increase of the ROS generation in lymph and a decrease of activities of enzymatic antioxidants in hemocytes of the insects after the implant incorporation. The authors suggest that the key role in maintenance of the oxidation-reduction balance in hemolymph at development of the incapsulation process is played by the lymph non-enzymatic antioxidants.

[An activity of nonspecific esterases in homogenates of Lymnaea stagnalis and Lymnaea tumida snails (Gastropoda: Pulmonata) infected by trematode cercariae Echinoparyphium aconiatum and Moliniella anceps (Echinostomatidae)].

The comparative analysis of esterase changes in homogenates of the snails Lymnaea stagnalis and L. tumida bodies was carried out. Juvenile snails with shell size 2 mm, 3-4 mm, 5-6 mm and 7-8 mm were exposed to cercariae of the trematodes Echinoparyphium aconiatum and/or Moliniella anceps. The esterase activity was detected spectrofotometrically. The highest level of esterase activity in noninfected L. stagnalis was registered in snails with shell size 3-4 mm. The invasion of snails by trematode cercariae results in a change of esterase activity in the tissues of infected snails. The activity of easterases was increased in the infected L. stagnalis snails with shell size 5-8 mm at 2 days post invasion in comparison with control. The decrease of esterase activity in tissues of infected snails L. stagnalis (3-4 mm) and L. tumida (4 mm) was observed at 26 days post invasion by E. aconiatum only. The host size and parasite species was influenced on esterase activity in the snails.

[An effect of the microsporidian Vairimorpha ephestiae (Microsporidia: Burenellidae) on activity and spectrum of nonspecific esterases in different tissues of the greater wax moth galleria mellonella (Lepidoptera: Pyralidae) larvae].

The effect of the microsporidian Vairimorpha ephestiae Matted (Microsporidia: Burenellidae) on nonspecific esterases was studied in hemolymph, fat body and midgut of the larvae of Galleria mellonella L. (Lepidoptera: Pyralidae). Esterase patterns were analyzed by the polyacrylamide gel electrophoresis, the total esterase activity was detected spectrophotometrically. The increase of total esterase activity was registered in hemolymph of inflected larvae. An overexpression of esterase isozyme in hemolymph was already detected at the 3rd day post infection. No changes in esterases pattern were observed in the fat body's homogenates of the G. mellonella larvae possessing the symptoms of microsporidiosis. The degradation of esterase isozymes and the decrease of total esterase activity in the pattern of the midgut homogenates of infected larvae were registered during parasite sporogony. The greatest esterase activity in hemolymph and midgut tissues was registered during vegetative reproduction of parasite, but the least level of esterase activity was observed during mass sporogony of microsporidia.

[Microsporidiosis in the wax moth Galleria mellonella (Lepidoptera: Pyralidae) caused by Vairimorpha ephestiae (Microsporidia: Burenellidae)]. / Mikrosporidioz pchelinoi ognevki Galleria mellonella (Lepidoptera: Pyralidae), vyzyvaemyi Vairimorpha ephistiae (Microsporidia: Burenellidae).

An experimental microsporidiosis of the wax moth caterpillars from laboratory population had been caused by oral infecting of early stages larvae and by intracavity injections of the spores of the microsporidian species Vairimorpha ephestiae. Peculiarities of microsporidiosis proceeding, manifestations of host defence reactions, and also an effect of the temperature of caterpillars cultivation and conditions of spores keeping on liability of the insects to the infection were studied. The effect of the microsporidia on the host organism was the early death or the delay of larvae development, but in several cases external manifestations of the effect of the parasite on the host were absent. The development of the parasites from the moment of infecting to the appearing of the mature spores congestions in the host organism proceeded 6 days. Microsporidia invaded insect fat body and caused its hypertrophy and disappearance of lipid granules. In the intestine and salivary glands microsporidia were not observed in the period from 6 to 16 day of the development. On the final stage of microsporidiosis the all contents of fatty tissue cells were replaced by spores of microsporidia. Under microscope only diplocaryotic spores of the Nozema type had been found in infected and died specimens, but not octospores. The spores threw out polar tubes under the change of pH in incubating solution from neutral to alkaline. The effects of microsporidiosis on the wax moth haemolymph were the increased rate of prohaemocytes, appearing of multinuclear free-circulating cells at 6 day after infection, and suppression of the reaction of haemolymph melanization with the mass sporogenesis of the parasite. The characteristic symptom of the wax moth microsporidiosis had been revealed, accumulation of black points and small spots of irregular form under cuticle ("reaction of attretization"). Increase of the temperature of insect cultivation up to 32 degrees C during 3 days after infection contributed to the full deliverance of the insects from the infection in first and second generations. It can be considered as a method of treatment of wax moth laboratory colonies from microsporidiosis. Oral infection of III and IV stage caterpillars by the spores being kept during 3-6 months under 4 degrees C in form of water suspension caused the death of 63.0-61.5 and 91% of caterpillars being cultivated under 25 and 21 degrees C respectively. Under the temperature of cultivation equal 30 degrees C the mortality did not differ from the control sample (8-10%). The spores extracted from dried bodies of caterpillars lost their vitality. It was demonstrated by the test on infectious ability in vivo and by acridine orange staining. This host-parasite system appears to be perspective in investigations of resistance mechanisms in insects and immunosuppressive features of entomopathogen microsporidia.