Digestive and respiratory tracts are inhabited by rich bacterial communities that can vary between their different segments. In comparison with other bird taxa with developed caeca, parrots that lack caeca have relatively lower variability in intestinal morphology. Here, based on 16S rRNA metabarcoding, we describe variation in microbiota across different parts of parrot digestive and respiratory tracts both at interspecies and intraspecies levels. In domesticated budgerigar (Melopsittacus undulatus), we describe the bacterial variation across eight selected sections of respiratory and digestive tracts, and three non-destructively collected sample types (faeces, and cloacal and oral swabs). Our results show important microbiota divergence between the upper and lower digestive tract, but similarities between respiratory tract and crop, and also between different intestinal segments. Faecal samples appear to provide a better proxy for intestinal microbiota composition than the cloacal swabs. Oral swabs had a similar bacterial composition as the crop and trachea. For a subset of tissues, we confirmed the same pattern also in six different parrot species. Finally, using the faeces and oral swabs in budgerigars, we revealed high oral, but low faecal microbiota stability during a 3-week period mimicking pre-experiment acclimation. Our findings provide a basis essential for microbiota-related experimental planning and result generalisation in non-poultry birds.

• Klíčová slova
• Budgerigar, Domestic parakeet, Gastrointestinal tract microbiota, Microbiome composition, Psittaciformes, Symbiosis,
• MeSH
• Bacteria genetika   MeSH
• dýchací soustava mikrobiologie   MeSH
• mikrobiota * MeSH
• papouškovití * genetika   MeSH
• RNA ribozomální 16S genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• RNA ribozomální 16S MeSH

During early ontogeny, microbiome affects development of the gastrointestinal tract, immunity, and survival in vertebrates. Bird eggs are thought to be (1) initially sterile (sterile egg hypothesis) and (2) colonized after oviposition through horizontal trans-shell migration, or (3) initially seeded with bacteria by vertical transfer from mother oviduct. To date, however, little empirical data illuminate the contribution of these mechanisms to gut microbiota formation in avian embryos. We investigated microbiome of the egg content (day 0; E0-egg), embryonic gut at day 13 (E13) and female faeces in a free-living passerine, the great tit (Parus major), using a methodologically advanced procedure combining 16S rRNA gene sequencing and microbe-specific qPCR assays. Our metabarcoding revealed that the avian egg is (nearly) sterile, but acquires a slightly richer microbiome during the embryonic development. Of the three potentially pathogenic bacteria targeted by qPCR, only Dietzia was found in E0-egg (yet also in negative controls), E13 gut and female samples, which might indicate possible vertical transfer. Unlike in poultry, we have shown that major bacterial colonization of the gut in passerines does not occur before hatching. We emphasize that protocols that carefully check for environmental contamination are critical in studies with low-bacterial biomass samples.

• Klíčová slova
• egg microbiome, embryo, gastrointestinal tract microbiota, passerine bird, pathogenic bacteria, sterile egg,
• MeSH
• Bacteria genetika   MeSH
• mikrobiota * MeSH
• Passeriformes * mikrobiologie   MeSH
• RNA ribozomální 16S genetika   MeSH
• střevní mikroflóra * MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• RNA ribozomální 16S MeSH

INTRODUCTION: Decreasing biotic diversity with increasing latitude is an almost universal macroecological pattern documented for a broad range of taxa, however, there have been few studies focused on changes in gut microbiota (GM) across climatic zones. METHODS: Using 16S rRNA amplicon profiling, we analyzed GM variation between temperate (Czechia) and tropical (Cameroon) populations of 99 passerine bird species and assessed GM similarity of temperate species migrating to tropical regions with that of residents/short-distance migrants and tropical residents. Our study also considered the possible influence of diet on GM. RESULTS: We observed no consistent GM diversity differences between tropical and temperate species. In the tropics, GM composition varied substantially between dry and rainy seasons and only a few taxa exhibited consistent differential abundance between tropical and temperate zones, irrespective of migration behavior and seasonal GM changes. During the breeding season, trans-Saharan migrant GM diverged little from species not overwintering in the tropics and did not show higher similarity to tropical passerines than temperate residents/short-distance migrants. Interestingly, GM of two temperate-breeding trans-Saharan migrants sampled in the tropical zone matched that of tropical residents and converged with other temperate species during the breeding season. Diet had a slight effect on GM composition of tropical species, but no effect on GM of temperate hosts. DISCUSSION: Consequently, our results demonstrate extensive passerine GM plasticity, the dominant role of environmental factors in its composition and limited effect of diet.

• Klíčová slova
• climatic zones, faecal microbiome, gastrointestinal tract, metabarcoding, passerine birds,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Animals form complex symbiotic associations with their gut microbes, whose evolution is determined by an intricate network of host and environmental factors. In many insects, such as Drosophila melanogaster, the microbiome is flexible, environmentally determined, and less diverse than in mammals. In contrast, mammals maintain complex multispecies consortia that are able to colonize and persist in the gastrointestinal tract. Understanding the evolutionary and ecological dynamics of gut microbes in different hosts is challenging. This requires disentangling the ecological factors of selection, determining the timescales over which evolution occurs, and elucidating the architecture of such evolutionary patterns. RESULTS: We employ experimental evolution to track the pace of the evolution of a common gut commensal, Lactiplantibacillus plantarum, within invertebrate (Drosophila melanogaster) and vertebrate (Mus musculus) hosts and their respective diets. We show that in Drosophila, the nutritional environment dictates microbial evolution, while the host benefits L. plantarum growth only over short ecological timescales. By contrast, in a mammalian animal model, L. plantarum evolution results to be divergent between the host intestine and its diet, both phenotypically (i.e., host-evolved populations show higher adaptation to the host intestinal environment) and genomically. Here, both the emergence of hypermutators and the high persistence of mutated genes within the host's environment strongly differed from the low variation observed in the host's nutritional environment alone. CONCLUSIONS: Our results demonstrate that L. plantarum evolution diverges between insects and mammals. While the symbiosis between Drosophila and L. plantarum is mainly determined by the host diet, in mammals, the host and its intrinsic factors play a critical role in selection and influence both the phenotypic and genomic evolution of its gut microbes, as well as the outcome of their symbiosis.

• Klíčová slova
• Drosophila melanogaster, Experimental evolution, Gut microbiota evolution, Host–microbe symbiosis, Lactiplantibacillus plantarum, Mouse, Whole genome sequencing,
• MeSH
• Drosophila melanogaster genetika   MeSH
• Drosophila MeSH
• mikrobiota * MeSH
• myši MeSH
• savci MeSH
• střevní mikroflóra * MeSH
• symbióza MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Gut microbiota (GM) often exhibit variation between different host species and co-divergence with hosts' phylogeny. Identifying these patterns is a key for understanding the mechanisms that shaped symbiosis between GM and its hosts. Therefore, both GM-host species specificity and GM-host co-divergence have been investigated by numerous studies. However, most of them neglected a possibility that different groups of bacteria within GM can vary in the tightness of their association with the host. Consequently, unlike most of these studies, we aimed to directly address how the strength of GM-host species specificity and GM-host co-divergence vary across different GM clades. We decomposed GM communities of 52 passerine species (394 individuals), characterized by 16S rRNA amplicon sequence variant (ASV) profiles, into monophyletic Binned Taxonomic units (BTUs). Subsequently, we analyzed strength of host species specificity and correlation with host phylogeny separately for resulting BTUs. We found that most BTUs exhibited significant host-species specificity in their composition. Notably, BTUs exhibiting high host-species specificity comprised bacterial taxa known to impact host's physiology and immune system. However, BTUs rarely displayed significant co-divergence with host phylogeny, suggesting that passerine GM evolution is not shaped primarily through a shared evolutionary history between the host and its gut microbes.

• Klíčová slova
• 16S rRNA, co‐divergence, gut microbiota, metabarcoding, passerines,
• Publikační typ
• časopisecké články MeSH

Mammals have a symbiotic relationship with various microorganisms called microbiota throughout their lives. These microorganisms are known to affect the host's physiology, health, and even mental balance. The development of the gut microbiota is regulated by a complex interaction between host and environmental factors, including diet and lifestyle. Herein, it is aimed to elucidate the differences in the gut microbiota of rats living in urban and rural habitats. The taxonomic changes in the gut microbiota of wild rats belonging to Rattus rattus species caught from urban and rural areas of Western Anatolian (Bilecik province) were examined comparatively by 16S rRNA next-generation sequencing technique. Laboratory rats were used as reference animals. The alpha diversities were found lower in the rural rats with respect to the urban rats, whereas the highest alpha diversity was calculated for laboratory rats. The lower Firmicutes to Bacteroidetes ratios (F/B ratio) were accounted for both rural and laboratory rats compared with urban rats. The Proteobacteria to Actinobacteria ratio (P/A ratio) was lower for rural rats, but higher for laboratory rats, compared with urban rats. The heatmap analyses of taxonomic units in the microbiota of each group demonstrated distinct patterns at the species and genus levels. The study provided metagenomic data on the gut microbiota of rats residing in urban and rural habitats, offering a different perspective on future environmental biomonitoring studies.

• MeSH
• krysa rodu Rattus MeSH
• metagenom MeSH
• metagenomika MeSH
• mikrobiota * MeSH
• RNA ribozomální 16S genetika   MeSH
• savci genetika   MeSH
• střevní mikroflóra * genetika   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• RNA ribozomální 16S MeSH

Postbiotics are health-promoting microbial metabolites delivered as a functional food or a food supplement. They either directly influence signaling pathways of the body or indirectly manipulate metabolism and the composition of intestinal microflora. Cancer is the second leading cause of death worldwide and even though the prognosis of patients is improving, it is still poor in the substantial part of the cases. The preventable nature of cancer and the importance of a complex multi-level approach in anticancer therapy motivate the search for novel avenues of establishing the anticancer environment in the human body. This review summarizes the principal findings demonstrating the usefulness of both natural and synthetic sources of postbotics in the prevention and therapy of cancer. Specifically, the effects of crude cell-free supernatants, the short-chain fatty acid butyrate, lactic acid, hydrogen sulfide, and β-glucans are described. Contradictory roles of postbiotics in healthy and tumor tissues are highlighted. In conclusion, the application of postbiotics is an efficient complementary strategy to combat cancer.

• Klíčová slova
• GPR81, SCFA, colorectal cancer, functional food, intestinal metabolome, microbiome,
• MeSH
• beta-glukany farmakologie   MeSH
• butyráty farmakologie   MeSH
• kyselina mléčná farmakologie   MeSH
• kyseliny mastné těkavé metabolismus   farmakologie   MeSH
• lidé MeSH
• metabolom MeSH
• nádory dietoterapie   metabolismus   MeSH
• potravní doplňky mikrobiologie   MeSH
• prebiotika mikrobiologie   MeSH
• probiotika metabolismus   farmakologie   MeSH
• střevní mikroflóra účinky léků   MeSH
• sulfan farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• beta-glukany MeSH
• butyráty MeSH
• kyselina mléčná MeSH
• kyseliny mastné těkavé MeSH
• prebiotika MeSH
• sulfan MeSH

BACKGROUND: Hydrogen sulfide is the final product of sulfate-reducing bacteria metabolism. Its high concentration in the gut can affect adversely bowel environment and intestinal microbiota by toxicity and pH lowering. AIM OF REVIEW: The aim of the review was to give observations related to the properties of bacterial communities inhabiting the gut, with the emphasis on sulfate-reducing bacteria and lactic acid bacteria. KEY SCIENTIFIC CONCEPTS OF REVIEW: The conduction of meta-analysis was another goal, since it gave statistical observation of the relevant studies. The review literature consisted of more than 160 studies, published from 1945 to 2019. Meta-analysis included 16 studies and they were chosen from the Web of Science database. The systematic review gave important information about the development of gut inflammation, with emphasis on sulfate-reducing and lactic acid bacteria. Oppositely from sulfate-reducing bacteria, probiotic properties of lactic acid bacteria are effective inhibitors against inflammatory bowel disease development, including ulcerative colitis. These facts were confirmed by the conducted meta-analysis. The results and observations gained from the systematic review represent the emphasized importance of gut microbiota for bowel inflammation. On the other side, it should be stated that more studies in the future will provide even better confirmations.

• Klíčová slova
• Bowel inflammations, Hydrogen sulfide, Lactic acid bacteria, Probiotics, Sulfate-reducing bacteria, Toxicity, Ulcerative colitis,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Alterations in the gut microbiota composition and diversity seem to play a role in the development of chronic diseases, including inflammatory bowel disease (IBD), leading to gut barrier disruption and induction of proinflammatory immune responses. This opens the door for the use of novel health-promoting bacteria. We selected five Parabacteroides distasonis strains isolated from human adult and neonates gut microbiota. We evaluated in vitro their immunomodulation capacities and their ability to reinforce the gut barrier and characterized in vivo their protective effects in an acute murine model of colitis. The in vitro beneficial activities were highly strain dependent: two strains exhibited a potent anti-inflammatory potential and restored the gut barrier while a third strain reinstated the epithelial barrier. While their survival to in vitro gastric conditions was variable, the levels of P. distasonis DNA were higher in the stools of bacteria-treated animals. The strains that were positively scored in vitro displayed a strong ability to rescue mice from colitis. We further showed that two strains primed dendritic cells to induce regulatory T lymphocytes from naïve CD4+ T cells. This study provides better insights on the functionality of commensal bacteria and crucial clues to design live biotherapeutics able to target inflammatory chronic diseases such as IBD.

• Klíčová slova
• IBD, colitis, functional screening, holobiont, immune response, live biotherapeutic products (LBP), microbiota, probiotics,
• MeSH
• Bacteroidetes genetika   imunologie   izolace a purifikace   MeSH
• Caco-2 buňky MeSH
• DNA bakterií genetika   metabolismus   MeSH
• dospělí MeSH
• feces mikrobiologie   MeSH
• idiopatické střevní záněty imunologie   mikrobiologie   MeSH
• kolitida chemicky indukované   imunologie   mikrobiologie   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• kyselina trinitrobenzensulfonová škodlivé účinky   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• novorozenec MeSH
• regulační T-lymfocyty imunologie   MeSH
• střevní mikroflóra imunologie   MeSH
• střevní sliznice imunologie   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• myši MeSH
• novorozenec MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA bakterií MeSH
• kyselina trinitrobenzensulfonová MeSH

Accumulating evidence demonstrates the decisive role of the gut microbiota in determining the effectiveness of anticancer therapeutics such as immunogenic chemotherapy or immune checkpoint blockade in preclinical tumor models, as well as in cancer patients. In synthesis, it appears that a normal intestinal microbiota supports therapeutic anticancer responses, while a dysbiotic microbiota that lacks immunostimulatory bacteria or contains overabundant immunosuppressive species causes treatment failure. These findings have led to the design of clinical trials that evaluate the capacity of modulation of the gut microbiota to synergize with treatment and hence limit tumor progression. Along the lines of this Trial Watch, we discuss the rationale for harnessing the gut microbiome in support of cancer therapy and the progress of recent clinical trials testing this new therapeutic paradigm in cancer patients.

• Klíčová slova
• Gut microbiota, anticancer therapeutics, clinical trials,
• MeSH
• dysbióza MeSH
• imunoterapie MeSH
• lidé MeSH
• nádory * farmakoterapie   MeSH
• střevní mikroflóra * MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH