Bacterial inventories constructed using 16S rRNA sequencing revealed that the assemblages hosted by hibernating and active frogs were equally diverse but markedly differed in community membership and structure. Approximately 38% of the 96 observed bacterial genera were exclusive to one or the other group. Although ~60% of these genera possess urease-encoding genes and/or have member taxa that reportedly hydrolyze urea, hibernating frogs hosted a greater relative abundance and richer diversity of ureolytic organisms, including, notably, species of Pseudomonas and Arthrobacter. Amphibians, in whom urea accrual has a major osmoregulatory function, likely profit substantially by repurposing the nitrogen liberated from the bacterial hydrolysis of urea.
Thermal sensitivity of urease activity in a lysate prepared from bacteria collected from frog hindgut or mouse caecum. Mean ± SEM; N =3 samples (each a composite of three individuals; see text for deta ils) were tested at each temperature. Means identified by dissimilar letters were distinguishable (repeated – measures ANOVA; P <0.05).