An engineered bacterial symbiont allows noninvasive biosensing of the honey bee gut environment.

The honey bee is a powerful model system to probe host-gut microbiota interactions, and an important pollinator species for natural ecosystems and for agriculture. While bacterial biosensors can provide critical insight into the complex interplay occurring between a host and its associated microbiota, the lack of methods to noninvasively sample the gut content, and the limited genetic tools to engineer symbionts, have so far hindered their development in honey bees. Here, we built a versatile molecular tool kit to genetically modify symbionts and reported for the first time in the honey bee a technique to sample their feces.

Neuroactive metabolites modulated by the gut microbiota in honey bees.

Honey bees have emerged as a new model to study the gut-brain axis, as they exhibit complex social behaviors and cognitive abilities, while experiments with gnotobiotic bees have revealed that their gut microbiota alters both brain and behavioral phenotypes. Furthermore, while honey bee brain functions supporting a broad range of behaviors have been intensively studied for over 50 years, the gut microbiota of bees has been experimentally characterized only recently. Here, we combined six published datasets from metabolomic analyses to provide an overview of the neuroactive metabolites whose abundance in the gut, hemolymph and brain varies in presence of the gut microbiota.

Maturation state of colonization sites promotes symbiotic resiliency in the Euprymna scolopes-Vibrio fischeri partnership.

Background: Many animals and plants acquire their coevolved symbiotic partners shortly post-embryonic development. Thus, during embryogenesis, cellular features must be developed that will promote both symbiont colonization of the appropriate tissues, as well as persistence at those sites. While variation in the degree of maturation occurs in newborn tissues, little is unknown about how this variation influences the establishment and persistence of host-microbe associations.

MicroRNA-Mediated Regulation of Initial Host Responses in a Symbiotic Organ.

One of the most important events in an animal's life history is the initial colonization by its microbial symbionts, yet little is known about this event's immediate impacts on the extent of host gene expression or the molecular mechanisms controlling it. MicroRNAs (miRNAs) are short, noncoding RNAs that bind to target mRNAs, rapidly shaping gene expression by posttranscriptional control of mRNA translation and decay. Here, we show that, in the experimentally tractable binary squid-vibrio symbiosis, colonization of the light organ induces extensive changes in the miRNA transcriptome.

The impact of persistent colonization by on the metabolome of the host squid .

Associations between animals and microbes affect not only the immediate tissues where they occur, but also the entire host. Metabolomics, the study of small biomolecules generated during metabolic processes, provides a window into how mutualistic interactions shape host biochemistry. The Hawaiian bobtail squid, , is amenable to metabolomic studies of symbiosis because the host can be reared with or without its species-specific symbiont, In addition, unlike many invertebrates, the host squid has a closed circulatory system.

Using Colonization Assays and Comparative Genomics To Discover Symbiosis Behaviors and Factors in Vibrio fischeri.

The luminous marine Gram-negative bacterium () is the natural light organ symbiont of several squid species, including the Hawaiian bobtail squid, , and the Japanese bobtail squid, Work with has shown how the bacteria establish their niche in the light organ of the newly hatched host. Two types of strains have been distinguished based upon their behavior in cocolonization competition assays in juvenile , i.e.

Critical symbiont signals drive both local and systemic changes in diel and developmental host gene expression.

The colonization of an animal's tissues by its microbial partners creates networks of communication across the host's body. We used the natural binary light-organ symbiosis between the squid and its luminous bacterial partner, , to define the impact of colonization on transcriptomic networks in the host. A night-active predator, coordinates the bioluminescence of its symbiont with visual cues from the environment to camouflage against moon and starlight.

Symbiotic organs shaped by distinct modes of genome evolution in cephalopods.

Microbes have been critical drivers of evolutionary innovation in animals. To understand the processes that influence the origin of specialized symbiotic organs, we report the sequencing and analysis of the genome of , a model cephalopod with richly characterized host-microbe interactions. We identified large-scale genomic reorganization shared between and and posit that this reorganization has contributed to the evolution of cephalopod complexity.

Metabolic adaptation in the human gut microbiota during pregnancy and the first year of life.

Background: The relationship between the gut microbiome and the human host is dynamic and we may expect adjustments in microbiome function if host physiology changes. Metatranscriptomic approaches should be key in unraveling how such adjustments occur.

Methods: We employ metatranscriptomic sequencing analyses to study gene expression in the gut microbiota of infants through their first year of life, and of their mothers days before delivery and one year afterwards.

A genomic comparison of 13 symbiotic Vibrio fischeri isolates from the perspective of their host source and colonization behavior.

Newly hatched Euprymna scolopes squid obtain their specific light-organ symbionts from an array of Vibrio (Allivibrio) fischeri strains present in their environment. Two genetically distinct populations of this squid species have been identified, one in Kaneohe Bay (KB), and another in Maunaloa Bay (MB), Oahu. We asked whether symbionts isolated from squid in each of these populations outcompete isolates from the other population in mixed-infection experiments.