Human Gut Microbiomes

Gut microbiota is a complex community of micro-organism species that live within the digestive tract. It is the largest reservoir of micro-organisms mutual to both humans and animals. The Gut microbiome consist of as many as 1,000 types of bacteria. The microbiome also consists of as many as 10 times the amount of cells and roughly as many as 150 times as many genes as the human genome contains. The microbiome has a symbiotic relationship with its human host and it co-evolves. The gut microbiome is a finely tuned eco-system, but its development depends on a number of factors, such as:

The sheer diversity of the microbiota means that bodily disorders associated with the gut region (encompassing the stomach and intestines) are difficult to diagnose, and even harder to find the source of the disorder. Intestinal Bowel Disease (IBD) is a large category of bodily disorders associated with the gut. IBD most commonly manifests itself in two forms – Crohn’s Disease, and Ulcerative Colitis [1]. Crohn’s disease is arguably a more severe form of the disease, as the diseased tissue tends to go deeper into the intestines. Ulcerative Colitis, while still very detrimental and pain causing, causes inflammation of tissue at more of the surface level. The diseases affects a significant portion of the population, with a high rate of new cases discovered - between 20,000 and 100,000 people are diagnosed with types of IBD annually in North America [1]. The role of the microbiota in inducing intestinal diseases has been suspected.

Shortly after birth, a baby’s stomach is lined with intestinal bacteria called microbiota, and it’s supposed to remain there for the rest of this organism’s life span. In humans lower intestines there are billions of bacteria with almost 2000 different species that are

There is an ever-growing awareness of the possible potential for bacterial flora in the gut, also known as microbiota, to influence the gut-brain communication in health and disease.

Did you know that there are more than a thousand different types of different tiny organisms called microbiota living inside your digestive system? Most people are probably grossed out by that, but it’s actually a good thing. The organisms break down food that our bodies can’t so that we can get nutrients from it. The article Gut biogeography of the bacterial microbiota explains that there are a lot of factors that affect the lives of the microbiota inside our digestive system. What we eat is a big factor that affects how microbiota live. When we were babies and drank breast milk, our microbiota used the nutrients from the milk to outlive other bacteria that could have been harmful to us. Experiments done to prove this were called

Objectives: Necrotizing enterocolitis (NEC) is one of the most common and serious gastrointestinal diseases in preterm infants. The aim of this systematic review examines the effects of probiotics on preventing NEC in very-low birth weight (VLBL) infants with a focus on the Bifidobacterium species and its strains.

One of the most beautiful things that the female human body can do is birth another human . As the expectant mother waits for her offspring(s) to be born she begins to weigh out her birthing options, deciding between either a vaginal birth or a surgical delivery by Caesarean section. Though many go for the natural route and decide to deliver naturally many opt to do cesarean usually by doctors’ orders. This big decision can have a lot of long lasting effects on the child, as a majority of our needed gut microbiome bacteria is from our mothers during birth. Lets way out the pros and cons of this life altering decision by talking about the microbes involved in both delivery options.

In this study, the authors sought to examine the impact of certain gut microbes on body composition and metabolism. It has been previously reported that the microbial community composition is more similar between related individuals. Thus, the authors of this study used both monozygotic and dizygotic twin pairs that were “discordant” for obesity in that one of them was classified as obese while the other one was not, as a model for studying the correlation between gut microbiota and obesity and associated disorders. To do this, human fecal`microbes from each member of one of four discordant twin pairs was transplanted into mice that were germ-free. The authors also investigated which microbial taxa were more invasive, as well as the relationship between the phenotype of the host and invasiveness. They also examined how a human diet can impact on invasion and microbial niche. In order to examine this, mice that were coprophagic, meaning they consume fecal matter, were housed together.

As we are growing up, we are exposed to more microbiota from the environment and the food we eat. When we consider the microbiome in our gut as invasive species, like any other invasive species we can see that their chance of surviving in our body depends on niche and resources. The environment conditions such as temperature, pH, and aerobic/anaerobic will determine if a species occupy that space will thrive or not. “By viewing pathogens as invasive species, we see that the contexts in which they are able to cause disease are the same as those required for any other species that invades and proliferates in a community (Costello et al.,

The relationship between microbiota and human well-being is being recognized increasingly. Microbial communities are crucial to human health as they regulate immunological and metabolic pathways and alteration to them predisposes individuals to various diseases.4 This heavy dependence on microbes begins in the early stages of life, even before birth. Microbes colonize various sites in the body through many different processes. The gut microbiota is formed when the vaginal microbes, associated with preterm birth, access the placenta through the bloodstream and penetrate the intestinal epithelial barrier of the fetus.4 This was proven by two pioneer studies which investigated the microbial colonization of the fetus of pregnant mice by injecting a genetically labelled bacteria in the mice which was consequently found in the amniotic fluid of the offspring after a cesarean section.4 This proved maternal microbial transmission in mammals.

Symptoms of Crohn’s disease can be prevented with the interaction between the immune system and bacteria, parasites, or viruses. According to Velasquez-Manoff, “The cleaner one’s circumstances during childhood, scientists found, the greater one’s chances of developing IBD in adulthood” (63). This statement stands true in that childhood cleanliness can lead to autoimmune diseases such as Crohn’s disease. Pathogens are critical to a healthy problem-free gut, therefore, the presence of bacteria, parasites or viruses at birth and throughout childhood may bekey to the prevention of Crohn’s disease.

We have already seen from the previous research paper that there exists a symbiotic relationship between the human host and the micro biome ecosystem that lives within it. The mere fact that it is not possible to independently culture most of these bacteria is a testament to the dependency between the environment and the host. Most of these bacteria can only grow within the host and in the community of other bacteria that co-exist with it. The use of metagenomics testing has helped us better understand the nature of the gut micro biomes and also provide more information on microbial diversity as well as the representation of particular microbes. Another popular approach to analyzing the micro biome, the high-throughput

Infant feces and urine were collected at 3 and 12 months. We will study a subset of infants from the CHILD cohort with daily prenatal NNS exposure, plus an equal number of unexposed controls matched for key confounders (birth method, breastfeeding, and maternal body mass index). The fecal microbiome will be analyzed by shotgun metagenomics to identify microbial population structures, genes (KEGG orthologs) and metabolic pathways. The urinary metabolome will be analyzed by untargeted direct flow injection tandem mass spectrometry to identify host and microbial metabolites. Exposed versus unexposed infants will be compared to identify NNS-associated microboime and metabolome signatures.

Recent studies have identified gut microbiota as a contributing factor to the pathophysiology of obesity. Gut microbiota originates from the maternal vaginal tract at birth and colonizes the GI tract of the infant.[3] Thus, as an infant, the mother’s diet greatly influences microbiota composition via her breast milk or formula milk.

Microscopic studies of the human body have found that microbial cells greatly outnumber somatic cells with National Institutes of Health estimating the figure to be around 90%; these either being bacterial, fungal or otherwise non-human. Even though DNA sequencing techniques have allowed scientists to analyse the structures components and functions of some of these normal microbiota, a large fraction of them still remain unstudied and so therefore we have not yet understood the full extent as to the influence that they have on our physiology and development thus how effective our immunity and nutrition is.