Interactions with microorganisms might enable house dust mites (HDMs) to derive nutrients from difficult-to-digest structural proteins and to flourish in human houses. We tested this hypothesis by investigating the effects of changes in the mite culture growth and population of two HDM species on HDM microbiome composition and fitness. Growing cultures of laboratory and industrial allergen-producing populations of Dermatophagoides farinae (DFL and DFT, respectively) and Dermatophagoides pteronyssinus (DPL and DPT, respectively) were sampled at four time points. The symbiotic microorganisms of the mites were characterized by DNA barcode sequencing and quantified by qPCR using universal/specific primers. The population growth of mites and nutrient contents of mite bodies were measured and correlated with the changes in bacteria in the HDM microbiome. The results showed that both the population and culture age significantly influenced the microbiome profiles. Cardinium formed 93% and 32% of the total sequences of the DFL and DFT bacterial microbiomes, respectively, but this bacterial species was less abundant in the DPL and DPT microbiomes. Staphylococcus abundance was positively correlated with increased glycogen contents in the bodies of mites, and increased abundances of Aspergillus, Candida, and Kocuria were correlated with increased lipid contents in the bodies of mites. The xerophilic fungus Wallemia accounted for 39% of the fungal sequences in the DPL microbiome, but its abundance was low in the DPT, DFL, and DFT microbiomes. With respect to the mite culture age, we made three important observations: the mite population growth from young cultures was 5-8-fold higher than that from old cultures; specimens from old cultures had greater abundances of fungi and bacteria in their bodies; and yeasts predominated in the gut contents of specimens from young cultures, whereas filamentous mycelium prevailed in specimens from old cultures. Our results are consistent with the hypothesis that mites derive nutrients through associations with microorganisms.

• Klíčová slova
• Bacteria, Dermatophagoides farinae, Dermatophagoides pteronyssinus, Diet, Fungi, Gut, Nutrition, Symbiosis, Yeasts,
• MeSH
• Bacteria * klasifikace   MeSH
• bakteriální RNA analýza   MeSH
• druhová specificita MeSH
• fungální RNA analýza   MeSH
• houby * klasifikace   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• mikrobiota * MeSH
• populační dynamika MeSH
• Pyroglyphidae mikrobiologie   fyziologie   MeSH
• RNA ribozomální 16S analýza   MeSH
• RNA ribozomální 18S analýza   MeSH
• taxonomické DNA čárové kódování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální RNA MeSH
• fungální RNA MeSH
• RNA ribozomální 16S MeSH
• RNA ribozomální 18S MeSH

The effect of short-term nutrient deprivation was studied in five populations of the mite Tyrophagus putrescentiae with different microbiomes. The fresh weight, nutrient status, respiration, and population growth of the mites were observed for the five mite population-scale samples. The starvation caused the larvae and nymphs to be eliminated, resulting in a significant increase in the fresh weight of starved adult specimens. Three populations were negatively influenced by starvation, and the starved specimens were characterized by a decrease in nutrient status, respiration, and population growth. One population was not influenced or was slightly influenced by starvation, which had no effect on population growth or nutrient contents but caused a significant decrease in respiration. One population was positively influenced by starvation; the population growth increased in starved specimens, and starvation had no effect on respiration. Although starvation altered the bacterial profiles of the microbiomes, these differences were much smaller than those between the populations. The bacterial profiles of Staphylococcus, Bacillus, Kocuria, Brevibacterium, and unidentified Micrococcaceae and Enterobacteriaceae increased in starved specimens, whereas those of Bartonella and Solitalea-like genera were reduced in the starved mite populations. The profiles of the intracellular symbiont Cardinium decreased in the starved specimens, and the Wolbachia profile changes were dependent on the mite population. In mite populations, when the symbionts were rare, their profiles varied stochastically. Correlations between changes in the profiles of the bacterial taxa and mite fitness parameters, including nutrient status (lipids, proteins, saccharides, and glycogen contents), mite population growth, and respiration, were observed. Although the microbiomes were resistant to the perturbations caused by nutrition deficiency, the responses of the mites differed in terms of their population growth, respiration, and nutrient status.

• Klíčová slova
• Coprophagy, Fitness, Gut, Mites, Starvation, Symbionts,
• MeSH
• Acaridae mikrobiologie   fyziologie   MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• fyziologie bakterií MeSH
• hostitelská specificita MeSH
• mikrobiota * MeSH
• stravovací zvyklosti MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Background: Tyrophagus putrescentiae is a ubiquitous mite species in soil, stored products and house dust and infests food and causes allergies in people. T. putrescentiae populations harbor different bacterial communities, including intracellular symbionts and gut bacteria. The spread of microorganisms via the fecal pellets of T. putrescentiae is a possibility that has not been studied in detail but may be an important means by which gut bacteria colonize subsequent generations of mites. Feces in soil may be a vector for the spread of microorganisms. Methods: Extracts from used mite culture medium (i.e., residual food, mite feces, and dead mite bodies) were used as a source of feces-inhabiting microorganisms as food for the mites. Two T. putrescentiae populations (L and P) were used for experiments, and they hosted the intracellular bacteria Cardinium and Wolbachia, respectively. The effects of the fecal fraction on respiration in a mite microcosm, mite nutrient contents, population growth and microbiome composition were evaluated. Results: Feces from the P population comprised more than 90% Bartonella-like sequences. Feces from the L population feces hosted Staphylococcus, Virgibacillus, Brevibacterium, Enterobacteriaceae, and Bacillus. The mites from the P population, but not the L population, exhibited increased bacterial respiration in the microcosms in comparison to no-mite controls. Both L- and P-feces extracts had an inhibitory effect on the respiration of the microcosms, indicating antagonistic interactions within feces-associated bacteria. The mite microbiomes were resistant to the acquisition of new bacterial species from the feces, but their bacterial profiles were affected. Feeding of P mites on P-feces-enriched diets resulted in an increase in Bartonella abundance from 6 to 20% of the total bacterial sequences and a decrease in Bacillus abundance. The population growth was fivefold accelerated on P-feces extracts in comparison to the control. Conclusion: The mite microbiome, to a certain extent, resists the acquisition of new bacteria when mites are fed on feces of the same species. However, a Bartonella-like bacteria-feces-enriched diet seems to be beneficial for mite populations with symbiotic Bartonella-like bacteria. Coprophagy on the feces of its own population may be a mechanism of bacterial acquisition in T. putrescentiae.

• Klíčová slova
• Bartonella, bacteria, diets, feces, feeding, fungi, soil, transmission,
• Publikační typ
• časopisecké články MeSH

Mycophagy should not be considered as a single and homogeneous category of nutritional biology due to the specific symbiotic chitinolytic bacteria associated with mites and fungi. To test interaction among mites, fungi, and chitinolytic bacteria, experiments were conducted on the model species Tyrophagus putrescentiae (Schrank). Mucor sp, Alternaria alternata, Penicillium claviforme, P. griseofulvum, and Verticillium sp. were plated onto malt agar and offered to T. putrescentiae in the laboratory. Mites were evaluated utilizing microanatomical examination based on histology, excrement analysis using fluorescence microscopy, bacterial plating, impact of mite homogenate on fungi in Petri dishes, reproduction of mites feeding upon each fungus, and isolation of associated bacteria inside mites. There were clear differences regarding the digested spores of different fungi passing through the gut and subsequently in the feces. Abundances of bacterial cells in excrement also corresponded to the fungi offered. The extracts from mites had chitinolytic activity, and the plated bacteria are known to produce exochitinases. The various feeding patterns observed were caused by differences in the cell wall structures of the tested fungi. The study illustrates that mycophagy in saprophagous mites does not consist of a single pattern, but rather that it can be classified into several sub-patterns depending upon the digested fungal species and its parts. The results point to a nearly symbiotic relationship between chitinolytic bacteria and digested fungi in mycophagous microarthropods.

• Klíčová slova
• Tyrophagus putrescentiae, digestion, feeding habit, fungal food offer, specificity of chitinolytic bacteria,
• MeSH
• Acaridae fyziologie   MeSH
• fyziologie bakterií * MeSH
• fyziologie výživy zvířat * MeSH
• houby fyziologie   MeSH
• potravní řetězec * MeSH
• stravovací zvyklosti * MeSH
• symbióza * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Tyrophagus putrescentiae colonizes different human-related habitats and feeds on various post-harvest foods. The microbiota acquired by these mites can influence the nutritional plasticity in different populations. We compared the bacterial communities of five populations of T. putrescentiae and one mixed population of T. putrescentiae and T. fanetzhangorum collected from different habitats. MATERIAL: The bacterial communities of the six mite populations from different habitats and diets were compared by Sanger sequencing of cloned 16S rRNA obtained from amplification with universal eubacterial primers and using bacterial taxon-specific primers on the samples of adults/juveniles or eggs. Microscopic techniques were used to localize bacteria in food boli and mite bodies. The morphological determination of the mite populations was confirmed by analyses of CO1 and ITS fragment genes. RESULTS: The following symbiotic bacteria were found in compared mite populations: Wolbachia (two populations), Cardinium (five populations), Bartonella-like (five populations), Blattabacterium-like symbiont (three populations), and Solitalea-like (six populations). From 35 identified OTUs97, only Solitalea was identified in all populations. The next most frequent and abundant sequences were Bacillus, Moraxella, Staphylococcus, Kocuria, and Microbacterium. We suggest that some bacterial species may occasionally be ingested with food. The bacteriocytes were observed in some individuals in all mite populations. Bacteria were not visualized in food boli by staining, but bacteria were found by histological means in ovaria of Wolbachia-infested populations. CONCLUSION: The presence of Blattabacterium-like, Cardinium, Wolbachia, and Solitalea-like in the eggs of T. putrescentiae indicates mother to offspring (vertical) transmission. RESULTS of this study indicate that diet and habitats influence not only the ingested bacteria but also the symbiotic bacteria of T. putrescentiae.

• Klíčová slova
• 16S rRNA, Blattabacterium, Tyrophagus putrescentiae, Wolbachia, bacteria, feeding, symbiont,
• Publikační typ
• časopisecké články MeSH

To date, only morphological and anatomical descriptions of microwhip scorpions (Arachnida: Palpigradi) have been published. This very rare group is enigmatic not only in its relationships to other arachnids, but especially due to the fact that these animals dwell only underground (in caves, soil, and interstitial spaces). We observed the curious feeding habit of the microwhip scorpion Eukoenenia spelaea over the course of one year in Ardovská Cave, located in Slovakia's Karst region. We chose histology as our methodology in studying 17 specimens and based it upon Masson's triple staining, fluorescent light and confocal microscopy. Single-celled cyanobacteria (blue-green algae) were conspicuously predominant in the gut of all studied palpigrades. Digestibility of the consumed cyanobacteria was supported by the presence of guanine crystals, glycogen deposits and haemocytes inside the palpigrade body. Cyanobacteria, the oldest cellular organisms on Earth, are very resistant to severe conditions in caves, including even darkness. Therefore, the cyanobacteria are able to survive in dark caves as nearly heterotrophic organisms and are consumed by cave palpigrades. Such feeding habit is extraordinary within the almost wholly predacious orders of the class Arachnida, and particularly so due to the type of food observed.

• MeSH
• dieta MeSH
• gastrointestinální trakt anatomie a histologie   fyziologie   ultrastruktura   MeSH
• glykogen biosyntéza   MeSH
• guanin biosyntéza   MeSH
• heterotrofní procesy fyziologie   MeSH
• jeskyně mikrobiologie   MeSH
• mikroskopie elektronová rastrovací MeSH
• sinice fyziologie   MeSH
• štíři anatomie a histologie   fyziologie   ultrastruktura   MeSH
• stravovací zvyklosti fyziologie   MeSH
• tma MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Slovenská republika MeSH
• Názvy látek
• glykogen MeSH
• guanin MeSH

The occurrence of bacterial colonies in the mesenchymal tissue of Tyrophagus putrescentiae Schrank was studied. One algal and two fungal species were offered as food. The experiment was analysed histologically and via transmission electron microscopy and plating of the mite homogenate. The dominant bacterium species, the bacterium population density in the mesenchyme, the location of bacterium groups between the internal organs and the ultrastructure were investigated. There were conspicuous differences between food types tested. On Penicillium, the highest population of bacteria in the mesenchymal tissue was correlated with the chitinase activity in mite homogenate. In this homogenate, Serratia marcescens was highly dominant among the other plated bacteria and it exhibited strong chitinolytic and trehalolytic activity.

• MeSH
• Acaridae mikrobiologie   fyziologie   ultrastruktura   MeSH
• Alcaligenes faecalis izolace a purifikace   MeSH
• chitinasy analýza   MeSH
• elektronová mikroskopie MeSH
• Eukaryota MeSH
• krmivo pro zvířata MeSH
• mezoderm mikrobiologie   ultrastruktura   MeSH
• Penicillium izolace a purifikace   MeSH
• preference v jídle MeSH
• půda parazitologie   MeSH
• Serratia marcescens izolace a purifikace   MeSH
• výběrové chování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chitinasy MeSH
• půda MeSH