A parasite is an organism that lives in or on another organism at that organism’s expense. For most people, the thought of a parasite is usually in the form of leeches, tapeworms, or ticks. Within populations, parasites have the power to dictate the health of a population and which individuals survive. From an evolutionary standpoint, this can determine who in a population survives due to a parasites ability to kill off the defenseless, and therefore allow individuals with only specific traits to survive. Under the basic concept of natural selection: those who survive, pass on their traits, while the unfit individuals die and fail to pass their traits to the next generation. Parasites act as a controlling factor for which hosts and genes survive for reproduction. With this in mind, Charles R. Brown and Mary Bomberger Brown began a study to investigate the effect of parasitic cimicid bugs on the brood size of cliff swallows (Brown and Brown 2017).
Figure 1. Galápagos Islands, image from Google Maps
In 1998, one of Charles Darwin’s famous finches, the medium tree finch, was classified as threatened on the International Union for Conservation of Nature’s (ICUN) red list (BirdLife, 2018). The medium tree finch, otherwise known as Camahynchus pauper, was named for the size of its short, curved beak. It can be found living only on Floreana island, an island that is part of the Galapágos Islands archipelago (bottom center of fig. 1). Over the last couple hundred years, this finch has faced numerous threats to its survival in the form of habitat fragmentation and destruction, predation, and now specifically parasitism (Kleindorfer et al., 2014). In 2009, the species was bumped all the way up to being labelled as critically endangered, after its population numbers dipped, largely due to threats caused by humans (BirdLife, 2018).
Coral reefs are prime examples of thriving diversity, none more than the Coral Triangle, which is located in the ocean surrounding the archipelagos of the Philippines and other islands above Australia, pictured in the orange area of Figure 1. For hundreds of years, the Coral Triangle has fascinated scientists. This area contains more species of corals than any other area in the world, but scientists do not know how so many corals came to occupy the Coral Triangle. Recently, a group of scientists led by Danwei Huang came together to investigate four hypotheses on diversity in hopes to find which one is most accurate with regard to the corals of the region.
Figure 1. A map depicting the Coral Triangle in orange and ecologically similar regions surrounding it in blue (Figure 1 of Huang et al. 2018).
Understanding the role of microbes in our environment and how antimicrobial resistance and hospital acquired infections are spread in the healthcare environment are some of the highlights of modern science.
Our new environment
People living in the United States spend 90% of their time indoors (Klepeis et al 2016). We live in our homes, work in our office buildings, and spend recreational time in the gym. One such common indoor environment- where we are born, and get treated for illnesses- is the hospital. How has this shift into the indoors impacted human health? Studies have linked this new environment to diseases like asthma and allergies (Fujimura et al 2014). In 2011, there were an estimated 722,000 hospital acquired infections in the U.S. (Magill et al 2014). And these infections- termed nosocomial infections- are reported as a leading cause of patient deaths (Anderson 2002). Continue reading “Here Is What Scientists Are Doing to Combat the Dangers of the Healthcare Environment”
Is there something that affects more individuals worldwide than cancer, (either directly or through someone we know)? The answer is pregnancy. There are many complications that can arise throughout pregnancy, with spontaneous preterm labor affecting 5-18% of pregnancies. Preterm labor is childbirth that happens before a healthy delivery date, where the baby is not fully developed to survive on its own. Depending on where you live, preterm labor can be considered a death sentence not just for the infant, but for the mother as well. Infants who survive are more at risk for infection and health issues the earlier they were born (Romero et al. 2014). Logically and morally, it is imperative for civilisations to decrease the amount of pregnant women who go into preterm labor so as to decrease risk to mother and child.Continue reading “Changes in Microbiota of Amniotic Fluid Might be Critical to Predict Spontaneous Preterm Births”
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.”
Background: In 2012 periodontal disease affected 46% of adults in the United States, with 8.9% classified as severe (Eke et al. 2015). Before everyone starts freaking out and drinking mouthwash, let’s talk about periodontal disease. Periodontal disease means gum disease, anything from simple gum inflammation, all the way to the loss of bone and the teeth falling out (“Periodontal Gum Disease’, 2013). Below I included a figure to show the progression of the disease.
Normal progression of periodontal disease from healthy to severe periodontitis (Gromadzki)
This disease is caused by microbes in the dental plaque migrating into the gum pockets causing inflammation, which will cause the gum to recede and with it the connective tissue holding in the tooth (Teles et al. 2013). Since periodontal disease is caused by microbes, it would not be surprising if there were differences between the community of microbes living in the mouths of healthy individuals, and those with periodontal disease. For the purpose of this discussion the oral microbiome is referring to the community of bacteria in the mouth of an individual. In fact, with the use of next-gen sequencing of the oral microbiome, it may be possible to determine differences between the mircobiomes of healthy and diseased individuals. A 2012 study found that community diversity is higher in individuals with chronic periodontal disease, but the results were complicated with 123 species were more abundant in diseased individuals and with 53 species were more abundant in healthy individuals (Griffen et al. 2012).Continue reading “Can the Oral Microbiome indicate Periodontal Disease State?”
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”
Picture this, you are a field researcher who stumbles upon a population of diseased and mutated humans. These humans live in an environment plagued with disease and pollution. The question you have is whether the mutation in the humans caused the disease/pollution or if the disease/pollution caused the humans to mutate. This question forms the basis of what microbiologists are interested in today; is the gut microbiome causal in the formation of [autoimmune] diseases, or is the microbiota the result of the diseased environment in which they inhabit? Continue reading “Alterations of the gut microbiome in multiple sclerosis”
