'I' don't exist

and, are bacteria sending messages into space?

A quick look at the Holobiont biology. A new(ish) approach seeks to provoke a paradigm shift in the biological sciences. Biology has tended to focus on genetic variations and natural selection to explain trait variation. We now know that, in some cases, and we will certainly find more, microbes explain more biological trait variation in organisms than genes do. This is radical and so holobiont biology seeks to incorporate this understanding and much biology onto a much more holistic path than has happened so far. An individual’s predisposition to develop colon cancer, their body-mass index, and even their cholesterol levels, are more determined by the nature of their microbiome than by genetic inheritance.

This is a major move forward, the microbial world isn’t a ‘separate’ domain, microbes are everywhere and have an impact on all the Earth’s ecosystems.

A new approach in neuroscience?

I’ve been teaching this over the last few years, ‘I’ don’t exist, ‘I’ am an ecosystem.

We now know that anxiety, depression, and autism spectrum disorders are highly correlated to the gut microbiome. We know that flows of information between the brain and the gut influence what happens in the intestines, for example, the activity of functional immune effector cells. Flows of information heading from the gut to the brain influence mood, cognitive capacity, and mental health in general.

The composition of the gut microbiota has been shown to affect newborn and fetal neurological development.

“What about BDNF?” I can hear you asking. Well, Brain-derived neurotrophic factor is important stuff, It’s active in several parts of the brain that are involved with learning and memory, the basal forebrain, the hippocampus, and the cortex for example. It’s also involved with neurogenesis, new neurons growing from stem cells. Changes to the composition of the microbiota changes how Brain-derived neurotrophic factor is expressed in the hippocampus. It can also change serotonin signaling, serotonin influences mood, learning, memory, and cognition.

If one has a healthy, diverse gut microbiome then it’s busy sending signals to the brain that influence how we behave under stressful or stable situations.

A specific example.

Around the world, there are people taking GABA (gamma-aminobutyric acid, γ-aminobutyric acid) as a dietary supplement. There isn’t much evidence that this works, however. GABA is an inhibitory neurotransmitter. It lessens a nerve cell’s ability to receive, create, or send chemical messages to other nerve cells. GABA controls, and calms, the nerve cell hyperactivity associated with anxiety, stress, and fear.

Lactobacillus rhamnosus JB-1 changes the expression of GABA receptors (GABARs) in the brain, and this leads to lower anxiety and less depressive behavior.

I could go on but maybe that’s enough, a lot of this stuff is highly technical and the research papers are often a hard read! The above supports the idea that ‘I’ don’t exist, ‘I’ am an ecosystem.

Tomorrow’s psychiatrists, if they are any good, will have to take into consideration that a psychiatric disorder may be due to a microbiome imbalance or disruption. As with holobiont biology so for neuroscience in general, holobiont neuroscience maybe? The role of the micro-organisms in and on our bodies is so important and so integrated with who and how we are that we cannot continue to brush the thing aside.

Probiotics with or after antibiotics?

Basically, it doesn’t seem to make a difference in how well the gut microbiome reestablishes itself. However, the probiotics can encourage the proliferation of bacteria containing antibiotic-resistant genes.

Agriculture?

Taking this one step further we also need holobiont agriculture. The role that soil microbes play in the biogeochemical cycling of macro and micronutrients is essential for plants and animals. Soils with a functional microbiome stock carbon more than soils without. No-till soils have higher levels of soil microbes. Even studies that seemed to show little difference in the microbial biomass showed a difference in taxonomic composition. Less beneficial in tilled fields compared to non or reduced tillage fields. Tillage tends to make a soil more homogenous and so it has a lower diversity of micro-habitats which leads to a less diverse soil microbiome. And then it all gets complex because soils also contain fungi!

Where plant diversity is high there are more root exudates and these are more varied. This tends to not only increase both microbial and fungal diversity, it also changes the ratio between the two. Diverse pastures tend to have more fungi and so higher levels of carbon sequestration. If a soil lacks fungi and is dominated by bacteria then it will tend to have lower rates of carbon sequestration and higher levels of nitrogen loss.

Then we have to add in animals and grazing. When a field is grazed the level of the bacterial biomass is reduced, but its diversity increases. This changes what the microbes are doing and levels of denitrification, carbon fixation and nitrogen reduction are decreased. However fungal diversity and biomass are higher in grazed fields and this means higher levels of carbon sequestration.

Compost tea?

Polycultures, no-till, no synthetic chemicals, and mulching with hyper-local materials are probably the best ways to encourage a healthy diverse soil microbiome and a good microbe/fungi ratio. That said, microbes and enzymes in aerated, non-sterilised compost tea can inhibit a bunch of plant pathogens like fusarium.

Are bacteria in contact with their cousins in space?

Electric bacteria breathe metals. They consume and excrete electrons. They are covered in nanotubes (e-pili and cytochromes) that they can shoot out to exchange electrons and thus keep themselves powered up. If that isn’t enough there are also cable bacteria, no, I’m not making this up. These cable bacteria form chains, one cell in diameter and thousands of cells long. Electrons from oxidised sulphur (in a place where oxygen is depleted) flow along the cable to a place where oxygen is available. The electrons are exchanged to the oxygen. In the world of electromicrobiology, these are called e-communities. Yup, they got there first!

I’m a bit suspicious about what’s going on, I reckon, no sorry, my ecosystem reckons that these electric and cable bacteria are very likely connected to a galactic internet. What is embarrassing is that they are probably sending out messages about us Humans. Like, catch the next asteroid and come and visit Earth, there’s this species that thinks it’s in control!! We know they have a sense of humour, they tricked us into thinking that we had discovered extra-terrestrial bacteria on the Bennu asteroid samples. In fact, they got there first and contaminated the samples for a laugh, probably.