New research supports holobiont conceptArticle first published on META-Evolution Blog.
The META-Health and Permaculture concept of symbiosis into creation of an organism on micro- as on macro-levels is now being supported by the conclusion of new scientific research.
Kiel University investigated how our microbiome development is controlled by the nervous system:
During the development of the nervous system of a hydra from egg stage to a fully-grown organism, it's microbiome changes drastically in only 3 weeks, until it finally stabilizes in composition and local variations. From that, the researchers deduct original and universally valid principles of the nerve system's functioning: the nerve cells produce neuropeptides (messengers consisting of amino acids) that suppress or allow the population by certain strains of bacteria. 
"Up to now, neuronal factors that influence the body's bacterial colonisation were largely unknown. We have been able to prove that the nervous system plays an important regulatory role here," emphasises Professor Thomas Bosch, evolutionary developmental biologist and spokesperson of the Collaborative Research Centre 1182 "Origin and Function of Metaorganisms," funded by the German Science Foundation (DFG).
The current article in Science Daily describes the findings.
In our organisms, the steering system communicates with information carriers and executive organs, organelles and microbes, and this communication and symbiosis is introduced during early stages of development!
Integrated in this orchestra are bacteria and virus, which not only create our individual and social
microbial fingerprint, but can change by our reaction to the environment . Thus, differentiations between separate life forms and those belonging to the body appear arbitrary - the mitochondria, power plants inside each of our cells performing cell respiration by transforming and regenerating energy in form of ATP, are originally imported bacteria! They possess own genetic information, and are separated from the cell plasma by a double membrane which needs different "nano-machines" for to import the necessary proteins. The collaboration of mitochondrial and nuclear genes for the sake of proteine biosynthesis is fine tuned. The understanding regarding origin and development of the mitochondria has also been updated by current research at Freiburg University:
The mitochondria derived from a simple bacteria that was assimilated by a bigger cell some 2 billion years ago, and which then transformed into a cell compartement - separate reaction chambers. Central requirement for the creation of mitochondria and for the evolution of complex cells was the development of an efficient transport machinery. Until now the assumption was that this machinery, once invented, merely underwent minor adaptations to the conditions of the respective organism. New data shows that although the nanomachines for protein import consist of about 15 different proteins in both trypanosomes and humans, their construction lacks similarity. This illustrates that the system, except for 3 main components, was invented anew! The findings suggest that the first complex cell possessed only a simple import system, from which a highly developed nano-machine derived by a protracted process. Today's efficient import systems consisting of several modules have developed later than previously believed, after a first speciation of complex cells had already occurred.. 
That means that the integration of the oxygen-transforming bacteria into the animal body was a specific and attuned intelligent evolutionary step.
Just as intelligent is the synergy of microbes and bearers of information, the virus and their partners in our lymphatic system. I like to avoid the term "immune system", as it is associated with "good and bad", thereby being all too simplistic and misleading. The "biological black matter" defined as virus or similar to virus stabilizes the gut microbiome and the resilience of the community. These phages control the bacteria population and communicate in their turn with the body's lymphatic cells, sharing protein information and mediating tolerance or strategies in the individual as well as the social systems.
Contact with naturally present microbes increases even mental and psychological health. The mycobacterium vaccae for example, which thrives in cow dung and garden soil, has effect on the limbic system, the emotional centre of the brain. By releasing the transmitter serotonin, it creates happy feelings and reduces anxiety , . Dr Chris Lowry from Bristol University announces after his experiment with mice:
“These studies help us understand how the body communicates with the brain and why a healthy immune system is important for maintaining mental health. They also leave us wondering if we shouldn’t all be spending more time playing in the dirt.”
Read about the study here.
Dorothy Matthews from Sage Colleges in Troy, New York, deducted from her studies:
"We found that mice that were fed live M. vaccae navigated the maze twice as fast and with less demonstrated anxiety behaviors as control mice" "This research suggests that M. vaccae may play a role in anxiety and learning in mammals" "It is interesting to speculate that creating learning environments in schools that include time in the outdoors where M. vaccae is present may decrease anxiety and improve the ability to learn new tasks."
The symptoms of anxiety and depression affect also our lymphatic cells. T-lymphocytes responsible for learned immune modulation show increased spontaneous apoptosis (self-induced cell death) in depressive patients, as well as under chronic stress, while immune activations and inflammation appear simultaneously. In this context, tryptophane, a precursor to the happiness hormone serotonin and the sleep-regulating melatonin, plays a key role: tryptophane, which stimulates the composition of T-Lymphocytes, is degraded in inflammatory reactions. Even cognitive functions and learning capacity are decreased when T-cells are reduced and unfunctional .
These findings support our META-Health view of the lymphatic system as a function of identity and self-definition, and the area of conflict between safety by avoidance or limitation, and strength by confrontation: The key to resilience and a happy life is being part of an ecosystem, exchange with the environment and tolerance of variations. Sense of community makes strong. This could now even be demonstrated on the cellular level.sources:
 Lowry CA, et al., Identification of an immune-responsive mesolimbocortical serotonergic system: Potential role in regulation of emotional behavior, Neuroscience (2007)
pictures (via Wikimedia Commons):
www.mikro-foto.de Frank Fox
NCI Dr Triche