Tag: Bacteria

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Which came first, antibiotics, or antibiotic-resistance? A study of Uncontacted Amerindians.

The geographical location of the Yanomami tribe as a whole. The specific village exists in the highlighted region.   (Image courtesy of Viralfast)

Background

The Yanomami people are patches of isolated South American tribes who occupy mountainous regions of southern Venezuela. Recently, a Yanomami tribe of 34 subjects discovered by helicopter, was investigated by a team of researchers who accompanied medical care professionals who were providing care to the villagers. These researchers, Clemente et. al. (2015), then wrote the paper, “The microbiome of uncontacted Amerindians’ to analyze this population which was uniquely untouched by Western Society. An interesting topic that this research paper addresses is antibiotic-resistant bacteria. Antibiotic-resistance are the adaptations of a bacterial species in response to antibiotics. Antibiotics are medications that have been developed in more recent times to destroy bacteria cells but not human cells. They do this by targeting specific differences between the two types of cells, for instance, penicillin inhibits the synthesis of the peptidoglycan layer of bacterial cell walls a feature not present in animal cells. Other bacteria have distinct DNA replication processes and some antibiotics are able to interrupt that function as well. This Yanomami population is intriguing because their microbiomes are likely the most accurate representation of an ancient human microbiome due to their isolation from the Western world. The presence of antibiotic-resistant bacteria in the Yanomami gut provides evidence for the claim that antibiotic-resistant bacteria have been around since before the invention of antibiotics, so stay tuned for a persuasive evidentiary argument further down. Clemente et. al.  also state that the Yanomami population that is sampled is the most diverse microbiome ever recorded. It is important to understand what kind of diversity the researchers are talking about. The Yanomami show extremely high beta diversity when compared to Guahibo, Malawi, and U.S. populations but exhibit low alpha diversity amongst individuals in the village population. Beta diversity represents the differences in species composition among samples while alpha diversity is just the diversity of each sample. This means that the Yanomami microbiome sample is extremely unique but microbiomes within that sample are very similar, this is most likely due to the Yanomami leading vastly different lifestyles than Western societies and individuals in the village being in extremely close quarters with each other (eating the same food, drinking from the same water source, no waste removal, etc.). Continue reading “Which came first, antibiotics, or antibiotic-resistance? A study of Uncontacted Amerindians.”

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Bacteria Protect Cancer from Chemotherapy

In the picture there are bacteria fluorescing in green inside of a pancreatic cancer cell.
Figure 1: Bacteria, in green, inside a pancreatic cancer cell (picture from  Yong, 2017  , picture by  Leore Geller)

Background:

Between the years of 2010 and 2014 2,910,588 people died of cancer in the United States despite our best efforts to fight cancer with methods like chemotherapy and surgery (Howlader et al., 2017). While there are many reasons why cancers might prevail over our best efforts, a relatively common reason is the devolvement of chemotherapy resistance (Housman et al., 2014). This resistance can come in many forms; ranging from drug inactivation to changing the target site of the drug. In an attempt to combat resistance, chemotherapy drugs have been given out in cocktails containing multiple drugs that all work in a different way in the hope of killing all the resistant cells at once. This method was based off of the theory that while the mechanisms of resistance are known to be complex, the resistance always stems from cancer cells themselves. However this theory has been challenged in the last few years with the discovery that cancer cells could be protected from chemotherapy drugs by the normal cells (stroma) around the cancer cells (Feig et al., 2012; Klemm and Joyce, 2015). Continue reading “Bacteria Protect Cancer from Chemotherapy”

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Association Between The Human Microbiota and Type II Diabetes Mellitus

Microbes in a gut under magnifying glass (from www.diabetesdaily.com 2016)

Type II diabetes mellitus is increasing at an alarming rate, especially in children. According to the World Health Organization (WHO) statistics, the number of individuals with type II diabetes is projected to rise to more than 590 million by the year 2035 (Diabetes, 2017 and Upadhyaya, 2015). Type II diabetes is the result of the body’s resistance to insulin, a hormone that regulates blood sugar. The WHO states that type II is largely the effect of being overweight and very little exercise. Type I diabetes is distinguished by the bodies inability to produce insulin and there is no way to prevent it. Symptoms of type II diabetes include thirst, constant hunger, weight loss, vision loss, numbness in feet, and tiredness (Diabetes, 2017).  Scientists are trying to discover new ways to mediate the effects of type II diabetes and many think that the gut microbiota of the human body might correlate with diabetes in an interesting way. Continue reading “Association Between The Human Microbiota and Type II Diabetes Mellitus”

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Depression and Microbial Dysfunction: A Link Between Gut Microbiota and the Brain.

Background

Depression is a mood disorder that is heterogeneous in nature.  Depression  causes severe symptoms that affect how a person feels, thinks, and handles daily activities (NIMH, 2017).  According to the World Health Organization, depression affects over 300 million people and is a major worldwide contributor to the burden of diseases. This is especially pertinent considering that depression is one of the mood disorders associated with suicide, some others being anxiety, schizophrenia and PTSD.  On an annual basis suicide leads to the death of nearly 800,000 people and is the second leading cause of death within the age group of 15 to 29 year olds (WHO, 2017). The underlying causes of depression are a complex interaction of social, psychological, and biological factors. It is essential to analyze these factors to understand the contribution of each in the development and maintenance of major depressive disorders.   Continue reading “Depression and Microbial Dysfunction: A Link Between Gut Microbiota and the Brain.”

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The Gut Microbiome; a Battleground Between Pathogens and the Host/Gut-Residents

Picture courtesy of https://cathe.com/can-exercise-change-your-gut-microbiome

Background

A unique and diverse array of inter-specific relationships can be found within the microbiome of the human gut. Due to the constant flow of microbe-carrying nutrients through it, the gut is subject to a high risk of foreign invaders. Fortunately the immune system, as well as the digestive tract (with the help of its residential microbes), have processes to rid themselves of the pathogenic strains (Ichinohe et al, 2011).  These bodily systems provide a unique example of positive interactions between co-existent, and co-dependent, systems. Although the body can protect itself from damage induced by invading species, certain medical diseases such as inflammatory bowel disease (IBD) and Crohn’s disease (CD), when combined with inflammation and intestinal distress are prone to exhibit symptoms such as “severe muscle wasting and fat loss’ (Schieber et al 2015).  Although the gut biome and the immune system may not always be capable of preventing these resultant health issues on their own, in conjunction they are capable of properly defending the body from muscular wasting caused by pathogenic effects.

The intestinal tract, while utilizing physical and chemical forces to break down and absorb vital nutrients, also houses a diverse community of microorganisms, a microbiota. This microbiota, which aids in  increasing efficiency in digestion and absorption, is the product  of coevolution and tolerance within both the host (providing this environment) and the residential microorganisms (Schieber et al 2015). Continue reading “The Gut Microbiome; a Battleground Between Pathogens and the Host/Gut-Residents”

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A Look at Resolving Milk Allergies Through the Gut

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Milk Allergies affect 2-3% of children in developed countries (Høst 2002). Image from Pixabay user estefania17

Background

Cow’s Milk Allergies are the most common food allergy in children, affecting 2-3% of these individuals in developed countries (Høst 2002). In most cases 45-50% of those affected by milk allergies will naturally resolve their allergies by their 1st year of age (Høst 2002). Milk allergies are associated with hives wheezing and or coughing immediately after consumption and symptoms such as cramps, itching, and diarrhea which take time to develop. A true milk allergy differs from lactose intolerance in that a milk allergy will involve actual immune system response whereas intolerance does not. The reasoning for allergy resolution is quite unclear but Bunyavanich et al. uses her study to connect allergy resolution to microbiome composition. To better understand this work,we can look at allergic responses and digestive issues as a response or the inability of the living microorganisms in the human body’s inability to process these allergens (Round & Mazmanian 2009). Continue reading “A Look at Resolving Milk Allergies Through the Gut”