Microbial Diversity in Commercial Bee Pollen from Europe, Chile, and Mexico, Based on 16S rRNA Gene Amplicon Metagenome Sequencing

Bee wisdom: exploring bee control strategies for food microflora by comparing the physicochemical characteristics and microbial composition of beebread

IMPORTANCE

Bees are a valuable model for investigating the relationship between environmental factors, gut microbiota, and organismal health. Beebread, produced from collected pollen, is a natural food source and a primary reservoir of gut microorganisms. Although pollen typically has diverse bacterial species, beebread has low species richness and bacterial abundance. Consequently, considerable attention has been paid to the adaptive strategies employed by honey bees to cope with the microorganisms within their food environment during co-evolution with plants. This study identified the distribution patterns of beebread's physicochemical characteristics, showing how bees use fermentation to enrich specific microbes. These findings help understand the relationship between environmental and food-associated microbes and bee intestinal microbiota. They also bridge gaps in the literature and provide a valuable reference for studying the complex interplay between these factors.

Changes of microorganism composition in fresh and stored bee pollen from Southern Germany

Analysis of plant pollen can provide valuable insights into the existing spectrum of microorganisms in the environment. When harvesting bee-collected pollen as a dietary supplement for human consumption, timely preservation of the freshly collected pollen is fundamental for product quality. Environmental microorganisms contained in freshly collected pollen can lead to spoilage by degradation of pollen components. In this study, freshly collected bee pollen was sampled at different locations and stored under various storage conditions to examine the hypothesis that storage conditions may have an effect on the composition of microorganisms in pollen samples. The samples were analyzed using 16S and 18S amplicon sequencing and characterized by palynological analysis. Interestingly, the bacterial communities between pollen samples from different locations varied only slightly, whereas for fungal community compositions, this effect was substantially increased. Further, we noticed that fungal communities in pollen are particularly sensitive to storage conditions. The fungal genera proportion Cladosporium and Mycosphaerella decreased, while Zygosaccharomyces and Aspergillus increased during storage. Aspergillus and Zygosaccharomyces fractions increased during storage at 30 °C, which could negatively impact the pollen quality if it is used as a dietary supplement.

Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR

Endospore-forming bacteria related to the Bacillus cereus group produce toxins that cause illnesses in organisms from invertebrates to mammals, including foodborne illnesses in humans. As commercial bee pollen can be contaminated with these bacteria, a comprehensive microbiological risk assessment of commercial bee pollen must be incorporated into the relevant regulatory requirements, including those that apply in Mexico. To facilitate detection of members of this group of bacteria, we have developed a PCR strategy that is based on the amplification of the single-copy tRNA^Cys gene and specific genes associated with tRNA^Cys to detect Bacillus cereus sensu lato (B. cereus s.l.). This tRNA^Cys-PCR-based approach was used to examine commercial bee pollen for endospore-forming bacteria. Our analysis revealed that 3% of the endospore-forming colonies isolated from a commercial source of bee pollen were related to B. cereus s.l., and this result was corroborated by phylogenetic analysis, bacterial identification via MALDI-TOF MS, and detection of enterotoxin genes encoding the HBL and NHE complexes. The results show that the isolated colonies are closely related phylogenetically to B. cereus, B. thuringiensis, and B. bombysepticus. Our results indicate that the tRNA^Cys-PCR, combined with other molecular tools, will be a useful approach for identifying B. cereus s.l. and will assist in controlling the spread of potential pathogens.

Bacterial Diversity Based on a 16S rRNA Gene Amplicon Data Set from a High-Altitude Crater Lake and Glacial Samples of the Iztaccihuatl Volcanic Complex (Mexico)

Little is known about extremophilic microorganisms from glaciers found in subtropical regions, and to our knowledge, no reports have identified glacial bacteria in this ecosystem in Mexico. Herein, we report a 16S rRNA gene amplicon data set demonstrating bacterial diversity of three samples from the Iztaccihuatl volcanic complex (Mexico) with a total of 115,701 to 138,805 high-quality reads.

Little is known about extremophilic microorganisms from glaciers found in subtropical regions, and to our knowledge, no reports have identified glacial bacteria in this ecosystem in Mexico. Herein, we report a 16S rRNA gene amplicon data set demonstrating bacterial diversity of three samples from the Iztaccihuatl volcanic complex (Mexico) with a total of 115,701 to 138,805 high-quality reads. The bacterial population was classified at the phylum level in all samples.