Social honey bees, Apis mellifera, host a set of distinct microbiota, which is similar across the continents and various honey bee species. Some of these bacteria, such as lactobacilli, have been linked to immunity and defence against pathogens. Pathogen defence is crucial, particularly in larval stages, as many pathogens affect the brood. However, information on larval microbiota is conflicting.Seven developmental stages and drones were sampled from 3 colonies at each of the 4 geographic locations of A. mellifera carnica, and the samples were maintained separately for analysis. We analysed the variation and abundance of important bacterial groups and taxa in the collected bees.Major bacterial groups were evaluated over the entire life of honey bee individuals, where digestive tracts of same aged bees were sampled in the course of time. The results showed that the microbial tract of 6-day-old 5th instar larvae were nearly equally rich in total microbial counts per total digestive tract weight as foraging bees, showing a high percentage of various lactobacilli (Firmicutes) and Gilliamella apicola (Gammaproteobacteria 1). However, during pupation, microbial counts were significantly reduced but recovered quickly by 6 days post-emergence. Between emergence and day 6, imago reached the highest counts of Firmicutes and Gammaproteobacteria, which then gradually declined with bee age. Redundancy analysis conducted using denaturing gradient gel electrophoresis identified bacterial species that were characteristic of each developmental stage.The results suggest that 3-day 4th instar larvae contain low microbial counts that increase 2-fold by day 6 and then decrease during pupation. Microbial succession of the imago begins soon after emergence. We found that bacterial counts do not show only yearly cycles within a colony, but vary on the individual level. Sampling and pooling adult bees or 6th day larvae may lead to high errors and variability, as both of these stages may be undergoing dynamic succession.

Lactobacillus bombi sp. nov., from the digestive tract of laboratory-reared bumblebee queens (Bombus terrestris) Three bacterial strains belonging to the genus Lactobacillus were isolated from the digestive tracts of laboratory-reared bumblebee queens (Bombus terrestris) using MRS agar under anaerobic conditions. The isolates were identified according to 16S rRNA gene sequence analysis as undescribed members of the genus Lactobacillus, with the highest 16S rRNA gene sequence similarity (96.9 %) to the uncharacterized bacterial strain Lactobacillus sp. Mboho2r2 isolated from the stomach of a European honeybee (Apis mellifera). Lactobacillus tucceti was found to be the closest related species with a validly published name, with 92.9 % 16S rRNA gene sequence similarity to the type strain. However, phylogenetic analyses based on different markers revealed that this species is phylogenetically very distant from the novel strains. The DNA G+C content of the proposed type strain BTLCH M1/2 T is 37.8 mol%. The fatty acids C 19 : 1 v6c and/or C 19 : 0 cyclo v10c/19v6, C 18 : 1 v9c and C 16 : 0 were predominant in all strains. Diphosphatidylglycerol, phosphatidylglycerol, a phospholipid, seven glycolipids and two phosphoglycolipids were detected in the novel strains. Growth was observed at 47 6C. The peptidoglycan type A4a L-Lys-D-Asp was determined for strain BTLCH M1/2 T. Genotypic characteristics and phylogenetic analyses based on the phylogenetic markers hsp60, pheS, rpoA and tuf as well as phenotypic characteristics and the results of chemotaxonomic analyses confirmed that the new isolates belong to a novel species of the genus Lactobacillus, for which the name Lactobacillus bombi sp. nov. is proposed. The type strain is BTLCH M1/2 T (5DSM 26517 T 5CCM 8440 T).

Three unknown Gram-stain-positive, catalase-negative, facultatively anaerobic and coccusshaped strains of bacteria were isolated from the digestive tracts of wasps (Vespula vulgaris). Analysis of 16S rRNA gene sequences revealed that these strains had identical sequences and showed that Vagococcus salmoninarum, with 96.2 % sequence similarity, was the closest phylogenetic neighbour. Further analyses based on hsp60 and pheS gene sequences of representatives of the family Enteroccocaceae and genotypic and phenotypic characterization using (GTG) 5 -PCR fingerprintings, EcoRI ribotyping, DNA G+C content, whole-cell protein profiling, cellular fatty acid profiles analysis and extensive biotyping confirmed that the investigated strains were representatives of a novel bacterial species within the genus Vagoccocus for which the name Vagoccocus entomophilus sp. nov. is proposed. The type strain is VOSTP2 T (5DSM 24756 T 5CCM 7946 T ).

Mucins are a family of large glycoproteins that represent the major structural components of the mucus and are encoded by 20 different mucin genes. Mucin expression can be modulated by different stimuli. In this study, we analyzed four mucins (MUC2, MUC3, MUC13, and MUC17) in coculture of Caco‐2/HT29‐MTX cells to demonstrate the variation in gene expression in the presence of antioxidant compounds like chlorogenic acid, epicatechin gallate, and quercetin (apple, tea, and coffee polyphenols, respectively). coculture of Caco‐2/HT29‐MTX cells was treated with polyphenols, and the expression of four mucins was determined by reverse‐transcriptase PCR. In addition, the secretion levels of MUC2 were established by enzyme‐linked immunoassay (ELISA) analysis. The results showed that each polyphenol compound induces different expression patterns of the mucin genes. Statistically significant up‐regulation of MUC17 was observed following incubation with epicatechin gallate and quercetin. ELISA results did not prove any significant differences in protein levels of MUC2 after treatment by the polyphenol compounds. The polyphenols considered in this study may influence mucin secretion and act on diverse salivary substrates to change the barrier properties of mucins for mucus secretion in different ways.

Background Knowledge of microbiota composition, persistence, and transmission as well as the overall function of the bacterial community is important and may be linked to honey bee health. This study aimed to investigate the inter-individual variation in the gut microbiota in honey bee larvae and pupae. Results Individual larvae differed in the composition of major bacterial groups. In the majority of 5th instar bees, Firmicutes showed predominance (70%); however, after larval defecation and during pupation, the abundance decreased to 40%, in favour of Gammaproteobacteria. The 5th instar larvae hosted significantly more ( P < 0.001) Firmicutes than black pupae. Power calculations revealed that 11 and 18 replicate-individuals, respectively, were required for the detection of significant differences ( P < 0.05) in the Bacteroidetes and Firmicutes abundance between stages, while higher numbers of replicates were required for Actinobacteria (478 replicates) and Gammaproteobacteria (111 replicates). Conclusions Although sample processing and extraction protocols may have had a significant influence, sampling is very important for studying the bee microbiome, and the importance of the number of individuals pooled in samples used for microbiome studies should not be underestimated. Electronic supplementary material The online version of this article (10.1186/s12866-019-1490-y) contains supplementary material, which is available to authorized users.

Detailed differentiation, classification, and phylogenetic analysis of the order Lactobacillales are performed using molecular techniques that involve the comparison of whole genomes, multilocus sequence analysis, DNA-DNA hybridisation, and 16S rRNA sequencing. Despite the wide application of the latter two techniques, issues associated with them are extensively discussed. Although complete genomic analyses are the most appropriate for phylogenetic studies, they are time-consuming and require high levels of expertise. Many phylogenetic/identification markers have been proposed for enterococci, lactobacilli, streptococci, and lactobacilli. However, none have been established for vagococci and some genera within the order Lactobacillales. The objective of the study was to find novel alternative housekeeping genes for classification, typing, and phylogenetic analysis of selected genera within the order Lactobacillales. We designed primers flanking variable regions of the infB (504 nt) and rpsB (333 nt) genes and amplified and sequenced them in 56 strains of different genera within the order Lactobacillales. Statistical analysis and characteristics of the gene regions suggested that they could be used for taxonomic purposes. Phylogenetic analyses, including assessment of (in)congruence between individual phylogenetic trees indicated the possibility of using the concatenation of the two genes as an alternative tool for the evaluation of phylogeny compared with the 16S rRNA gene representing the standard phylogenetic marker of prokaryotes. Moreover, infB, rpsB regions and their concatenate were phylogenetically consistent with two widely applied alternative genetic markers in taxonomy of particular Lactobacillales genera encoding the 60 kDa chaperonin protein (GroEL-hsp60) and phenylalanyl-tRNA synthetase, alpha subunit (pheS).

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Honey, which has been used as an ancient remedy for infected wounds, has been shown in laboratory studies to have antimicrobial action against a spectrum of bacteria and fungi. Because very little quantitative information exists on the microbiota of honey, the aim of this study was to quantify the Actinobacteria, Firmicutes, and Gammaproteobacteria groups in samples of honeydew honey and blossom honey from six regions in the Czech Republic, using quantitative real-time PCR analysis with specific primers based on the 16S rRNA gene. Gammaproteobacteria and Firmicutes were clearly the most abundant, predominating Actinobacteria in both types of honey. Most of the Firmicutes were detected in samples from South Bohemia (mean gene copies per 1 g honey: 5.6 × 105) and Ústí nad Labem Region (3.7 × 105), which contained the lowest number of Gammaproteobacteria (15.5 × 103). The Actinobacteria were prevalent in samples from Plzeň (4.3 × 103) and Central Bohemia (5.4 × 103), where conversely the Firmicutes were least abundant. Honey thus contains bacterial species with probiotic activity and oligosaccharides which can act as prebiotics, suggesting that its incorporation into the human diet may potentially impart significant health benefits to consumers compared with ‘empty calories’ consumed as refined sugar.