[Show abstract][Hide abstract] ABSTRACT: The synergistic effect in mortality of the greater wax moth Galleria mellonella larvae was recorded after combined treatment with the entomopathogenic fungi Cordyceps militaris (L.: Fr.) Link and Beauveria bassiana (Bals.-Criv.) Vuill. Treatment with C. militaris resulted in development arrest and some changes in immune response (a sharp decrease in the total hemocyte counts and encapsulation rate and an increase in phenoloxidase activity in the hemolymph) which were accompanied by higher susceptibility to B. bassiana. The larvae killed by combined treatment with two pathogens were colonized only by B. bassiana. The mechanisms of synergism under combined treatment of the greater wax moth with C. militaris and B. bassiana are discussed.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate, via various molecular methods, possible correlations between microbial community structure of Prussian carp and the environmental compartments of their habitat.
Microbial communities in the intestine and environmental compartments were studied using PCR-screening, cloning, and next generation high-throughput sequencing of the 16S ribosomal RNA genes. The 16S rDNA metagenomic sequencing showed higher bacterial diversity in comparison with clone libraries, while group-specific PCR showed positive detection of nine bacteria phyla. Proteobacteria, Bacteroidetes, Firmicutes, Cyanobacteria and Actinobacteria were most abundant both in the intestine and habitat environments. The comparative analyses reveal that the bacterial community in the Prussian carp intestine is most similar to that identified from the chironomid.
This study demonstrated some differences between molecular methods and showed advantages and limitations associated with them. These differences have the potential to reduce bias in results obtained from analysis of the community structure. The advantages of each molecular technique can be used for a better understanding of microbial diversity. The microbiota of Prussian carp intestine is most similar to those from the chironomids.
We investigated the diversity of the intestinal microbiota in an economically important aquaculture species, the Prussian carp (Carassius gibelio). The results provide significant information to discuss possible functions of these bacteria for further understanding of Prussian carp health. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host plants on insects' fitness, as well as the importance of this effect for the population dynamics of outbreaking species of insects, is a widespread and well-documented phenomenon. However, the spreading of this phenomenon through the food chain, and especially those mechanisms operating this spreading, are still unclear. In this paper, we study the effect of seasonally declined leafquality (estimated in terms of phenolics and nitrogen content) on herbivore fitness, immune parameters and resistance against pathogen by using the silver birch Betula pendula—gypsy moth Lymantria dispar—nucleopolyhedrovirus as the tritrophic system. We show that a phenological mismatch induced by the delay in the emergence of gypsy moth larvae and following feeding on mature leaves has negative effects on the female pupal weight, on the rate of larval development and on the activity of phenoloxidase in the plasma of haemolymph. In addition, the larval susceptibility to exoge-nous nucleopolyhydrovirus infection as well as covert virus activation were both enhanced due to the phenological mismatch. The observed effects of phenological mismatch on insect-baculovirus interaction may partially explain the strong and fast fluctuations in the population dynamics of the gypsy moth that is often observed in the studied part of the defo-liator area. This study also reveals some indirect mechanisms of effect related to host plant quality, which operate through the insect innate immune status and affect resistance to both exogenous and endogenous virus.
[Show abstract][Hide abstract] ABSTRACT: Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs), particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females' pupae weight (= fecundity) compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids.
[Show abstract][Hide abstract] ABSTRACT: Optimum pH of various digestive enzymes and physiological pH values were determined in the gastrointestinal tract of fish species, such as goldfish Carassius auratus gibelio, ide Leuciscus idus, wild carp Cyprinus carpio, perch Perca fluviatilis, and zander Sander lucioperca. Physiological values of pH in the stomach of perch and zander and in different parts of the intestine of all studied fish species range within 3.5-4.5 and 6.5-7.2, respectively. The maximum values of the activity of alkaline protease and nonspecific lipase and esterase are recorded at pH 8-9; the maximum acid protease activity is recorded at pH 2-3. The optimum pH activity of alkaline protease and nonspecific lipase and esterase do not correlate with actual pH value in the digestive tract of fish. Two peaks of α-amylase activity are observed at pH 7 and 9.
Full-text · Article · Mar 2015 · Journal of Ichthyology
[Show abstract][Hide abstract] ABSTRACT: Feeding habits and the activity of digestive enzymes (total alkaline proteases, α-amylase and lipase) from dace Leuciscus leuciscus, roach Rutilus rutilus, Prussian carp Carassius auratus gibelio, perch Perca fluviatilis and pikeperch Sander lucioperca fry were studied in the Malye Chany Lake–Kargat Estuary (western Siberia, Russia). The diet of fry from all studied species was mainly composed of chironomid larvae and zooplanktonic organisms (i.e. cladocera and copepoda), whereas carnivorous species such as P. fluviatilis and S. lucioperca also preyed on fry from other fishes while detritus and microalgae were also important in the diet of ommivorous species. When comparing diet similarity (Sørensen–Dice index, QS) among fry at different stages of development, both omnivorous and carnivorous species showed a high level of similarity (0·67 < QS < 0·89 and 0·73 < QS < 0·89, respectively). Diet similarity values were in agreement with the overall digestive activity profile analysed by cluster analysis. Diet similarity suggested potential trophic competition when zooplanktonic and benthic prey began to decline towards autumn. The analysis of pancreatic digestive enzymes revealed a correlation among their activities and fry feeding habits with α-amylase:total proteases (A:P) values higher than 1 in omnivorous species and lower (A:P ≤ 1) in carnivorous species.
Full-text · Article · Sep 2014 · Journal of Fish Biology
[Show abstract][Hide abstract] ABSTRACT: The immunosuppressive and insecticidal activity of culture of the entomopathogenic fungus Cordyceps militaris on the larvae of the Colorado potato beetle Leptinotarsa decemlineata has been established for the first time. It was found that the peroral effect of the fungal culture resulted in dose�dependent decrease in survival, delayed in development time and molting, decreases in the total hemocyt counts, increased activity of phenoloxidases in the hemolymph, and reduced activity of the enzyme in the cuticle, as well as increased sensitivity of larvae to the fungus Beauveria bassiana at the level of the synergistic effect.
[Show abstract][Hide abstract] ABSTRACT: The mortality rate of Anopheles messeae Fll. and Culex pipiens pipiens L. mosquito larvae infected with entopathogenic fungi Metarhizium brunneum and M. robertsii has been studied in laboratory conditions. It was shown that C. pipiens larvae are more susceptible to a water suspension of fungal conidia treatment while A. messeae larvae are more susceptible to treatment with dry conodia. The mortality of mosquito larvae infected with the most virulent strain and dose of 2 x 10(6) conidia per cm(2) was 87.5-92.5%. Prospects for the use of fungi in the biocontrol of bloodsucking mosquitoes are discussed
Full-text · Article · May 2014 · Contemporary Problems of Ecology
[Show abstract][Hide abstract] ABSTRACT: In this study the cellular and humoral immune reactions of the Greater wax moth Galleria mellonella have been investigated during bacterial infection caused by oral administration of Bacillus thuringiensis. Two different dose strengths were investigated to assess the contribution of immune parameters to induced Bt resistance. Low-dose (sublethal LC15) infection resulted in significantly elevated haemolymph phenoloxidase and lysozyme-like activity, enhanced phagocytic activity of haemocytes, and increased encapsulation responses in infected larvae at 48 and 72 h post infection. Higher doses of Bt (half-lethal LC50) also triggered significantly elevated haemolymph phenoloxidase and lysozyme-like activity, but decreased the coagulation index and activity of phenoloxidase in haemocytes of infected larvae. In both types of infection, the pool of circulating haemocytes became depleted. The importance of cellular and humoral immune reactions in induced insect resistance to intestinal bacterial infection Bt is herein discussed.
[Show abstract][Hide abstract] ABSTRACT: The diversity of microbial communities associated with the intestinal mucosa and the intestinal contents of fish with different nutritional profiles have been investigated. Differences in the intestinal microbiota of fish with different dietary preferences have been revealed using group-specific primers for the main large taxa of bacteria. Representatives of the phyla Planctomycetes, Vernicomicrobia, and Cyanobacteria have been detected in the intestinal contents of all investigated nonpredatory (crucian carp, roach, and dace) and predatory (pikeperch, pike, and perch) fish. Representatives of the phylum Firmicutes were detected in the intestinal mucosa and intestinal contents of predatory fish species, but not in those of the nonpredatory fish.
Full-text · Article · Apr 2014 · Inland Water Biology
[Show abstract][Hide abstract] ABSTRACT: A 'dark morph' melanic strain of the greater wax moth, Galleria mellonella, was studied for its atypical, heightened resistance to infection with the entomo-pathogenic fungus, Beauveria bassiana. We show that these insects exhibit multiple intraspecific immunity and physiological traits that distinguish them from a non-melanic, fungus-susceptible morph. The melanic and non-melanic morphs were geographical variants that had evolved different, independent defence strategies. Melanic morphs exhibit a thickened cuticle, higher basal expression of immunity-and stress-management-related genes, higher num-bers of circulating haemocytes, upregulated cuticle phenoloxidase (PO) activity concomitant with conidial invasion, and an enhanced capacity to encap-sulate fungal particles. These insects prioritize specific augmentations to those frontline defences that are most likely to encounter invading pathogens or to sustain damage. Other immune responses that target late-stage infection, such as haemolymph lysozyme and PO activities, do not contribute to fungal toler-ance. The net effect is increased larval survival times, retarded cuticular fungal penetration and a lower propensity to develop haemolymph infections when challenged naturally (topically) and by injection. In the absence of fungal infection, however, the heavy defence investments made by melanic insects result in a lower biomass, decreased longevity and lower fecundity in comparison with their non-melanic counterparts. Although melanism is clearly correlated with increased fungal resistance, the costly mechanisms enabling this protective trait constitute more than just a colour change.
Full-text · Article · Jul 2013 · Proceedings of the Royal Society B: Biological Sciences