The human body hosts more than ten thousand different kinds of microbes. Most of these bacteria aren’t harmful – in fact, many of them actually aid the immune system.
Microbiota and the healthy brain
Within the first few days of life, humans are colonized by commensal intestinal microbiota. Review of recent findings show that microbiota are important in normal healthy brain function. There exists a relation between stress and microbiota, and how alterations in microbiota influence stress-related behaviors.
Bacteria and the CNS
New studies show that bacteria, including commensal, probiotic, and pathogenic bacteria, in the gastrointestinal (GI) tract can activate neural pathways and central nervous system (CNS) signaling systems. Ongoing and future animal and clinical studies aimed at understanding the microbiota–gut–brain axis may provide novel approaches for prevention and treatment of mental illness, including anxiety and depression.
The healthy balance of microbial cells in our body is affected by many factors including antibiotics, acidic meds,narcotics,alcohol,sugar and more.
The new insights into NEC suggest why the microbiome suddenly seems so important to almost everything in the medical and biological worlds, even our understanding of what it means to be human. We tend to think that we are exclusively a product of our own cells, upwards of ten trillion of them. But the microbes we harbor add another 100 trillion cells into the mix.
The creature we admire in the mirror every morning is thus about 10 percent human by cell count. By weight, the picture looks prettier (for once): Altogether an average adult’s commensal microbes weigh about three pounds, roughly as much as the human brain. And while our 21,000 or so human genes help make us who we are, our resident microbes possess another eight million or so genes, many of which collaborate behind the scenes handling food, tinkering with the immune system, turning human genes on and off, and otherwise helping us function. John Donne said “no man is an island,” and Jefferson Airplane said “He’s a peninsula,” but it now looks like he’s actually a metropolis.
The modern microbiome era started in the late 1990s, when David Relman, an infectious disease physician at Stanford University, decided to get a sample of the microbes in his own mouth. It’s a simple process: A dentist scrapes a sort of elongated Q-tip across the outer surface of a tooth, or the gums, or the inside of a cheek. These samples typically look like nothing at all. (“You have to have a lot of faith in the invisible,” one dentistry professor advises.)
Stress and the Microbiota
There is now an expanding volume of evidence to support the view that commensal organisms within the gut play a role in early programming and later responsivity of the stress system. The gut is inhabited by 1013–1014 micro-organisms, which is ten times the number of cells in the human body and contains 150 times as many genes as our genome. It has long been recognised that gut pathogens such as Escherichia coli, if they enter the gut can activate the HPA.
However, animals raised in a germ-free environment show exaggerated HPA responses to psychological stress, which normalises with monocolonisation by certain bacterial species including Bifidobacterium infantis. Moreover, increased evidence suggests that animals treated with probiotics have a blunted HPA response.
Stress induces increased permeability of the gut
Stress induces increased permeability of the gut allowing bacteria and bacterial antigens to cross the epithelial barrier and activate a mucosal immune response, which in turn alters the composition of the microbiome and leads to enhanced HPA drive. Increasing data from patients with irritable bowel syndrome and major depression indicate that in these syndromes alteration of the HPA may be induced by increased gut permeability.
In the case of irritable bowel syndrome the increased permeability can respond to probiotic therapy. Detailed prospective studies in patients with mood disorders examining the gut microbiota, immune parameters and HPA activity are required to throw further light on this emerging area. It is however clear that the gut microbiota must be taken into account when considering the factors regulating the HPA.
Antibiotics can cause cell death
Recent studies have revealed that antibiotics can promote the formation of reactive oxygen species which contribute to cell death. In this study, we report that five different antibiotics known to stimulate production of reactive oxygen species inhibited growth ofEscherichia coli biofilm. We demonstrated that supression of biofilm formation was mainly a consequence of the increase in the extracellular concentration of indole, a signal molecule which suppresses growth of bacterial biofilm. Indole production was enhanced under antibiotic-mediated oxidative stress due to overexpression of tryptophanase (TnaA), which catalyzes synthesis of indole. We found that DMSO (dimethyl sulfoxide), a hydrogen peroxide scavenger, or the lack of trypthophanase, which catalyzes production of indole, partly restored formation of E. coli biofilm in the presence of antibiotics. In conclusion, these findings confirmed that antibiotics which promote formation of ROS (reactive oxygen species) can inhibit development of E. colibiofilm in an indole-dependent process.