Pancreatic Pseudoislets: An Organoid Archetype for Metabolism Research.

Pancreatic islets are vital endocrine regulators of systemic metabolism, and recent investigations have increasingly focused on understanding human islet biology. Studies of isolated human islets have advanced understanding of the development, function, and regulation of cells comprising islets, especially pancreatic α- and ß-cells. However, the multicellularity of the intact islet has stymied specific experimental approaches-particularly in genetics and cell signaling interrogation. This barrier has been circumvented by the observation that islet cells can survive dispersion and reaggregate to form "pseudoislets," organoids that retain crucial physiological functions, including regulated insulin and glucagon secretion. Recently, exciting advances in the use of pseudoislets for genetics, genomics, islet cell transplantation, and studies of intraislet signaling and islet cell interactions have been reported by investigators worldwide. Here we review molecular and cellular mechanisms thought to promote islet cell reaggregation, summarize methods that optimize pseudoislet development, and detail recent insights about human islet biology from genetic and transplantation-based pseudoislet experiments. Owing to robust, international programs for procuring primary human pancreata, pseudoislets should serve as both a durable paradigm for primary organoid studies and as an engine of discovery for islet biology, diabetes, and metabolism research.

Honey bee microbiome associated with different hive and sample types over a honey production season.

Western honey bees (Apis mellifera) are important pollinators in natural and agricultural ecosystems, and yet are in significant decline due to several factors including parasites, pathogens, pesticides, and habitat loss. A new beehive construction called the FlowTM hive was developed in 2015 to allow honey to be harvested directly from the hive without opening it, resulting in an apparent decrease in stress to the bees. Here, we compared the Flow and traditional Langstroth hive constructions to determine if there were any significant differences in the bee microbiome. The bee-associated bacterial communities did not differ between hive constructions and varied only slightly over the course of a honey production season. Samples were dominated by taxa belonging to the Lactobacillus, Bifidobacterium, Bartonella, Snodgrassella, Gilliamella, and Frischella genera, as observed in previous studies. The top ten most abundant taxa made up the majority of the sequence data; however, many low abundance organisms were persistent across the majority of samples regardless of sampling time or hive type. We additionally compared different preparations of whole bee and dissected bee samples to elaborate on previous bee microbiome research. We found that bacterial sequences were overwhelming derived from the bee guts, and microbes on the bee surfaces (including pollen) contributed little to the overall microbiome of whole bees. Overall, the results indicate that different hive constructions and associated disturbance levels do not influence the bee gut microbiome, which has broader implications for supporting hive health.