21 8 / 2014

pubhealth:

Know:BRCA - Everyone Has BRCA Genes
Everyone has BRCA genes, but some people have mutations (changes) in these genes which increase their risk for breast and ovarian cancer. Find out your family history of breast and ovarian cancer, then talk to your doctor about your own risks for these diseases.
(From CDC)

pubhealth:

Know:BRCA - Everyone Has BRCA Genes

Everyone has BRCA genes, but some people have mutations (changes) in these genes which increase their risk for breast and ovarian cancer. Find out your family history of breast and ovarian cancer, then talk to your doctor about your own risks for these diseases.

(From CDC)

18 8 / 2014

Well that’s just factually inaccurate.

1. Which “ice age”? Dinosaurs in general didn’t evolve until after a few “ice ages”, and they were well extinct (well, except for birds) before the last one. 

2. Theropods didn’t arise until the Triassic period which is generally known to be HOT AND HUMID! 

3. With the exclusion of small specialized coelurosaurian theropod dinosaurs (which would lead eventually to modern day birds), large ones like this guy in his underwear here (haha) were very well extinct (see no. 1) as the last GLACIAL period (not ice age ugh) was during the Pleistocene (roughly 2,000,000 - 12,000 years ago). Large theropods died out 65,000,000 years ago sooooo….. No. Lol he (or she) hasn’t had any friends for much longer than what he (or she) says haha aww now it’s depressing even more! Lol

Note: my specialty is evolutionary and developmental biology, so if I’m wrong here, please let me know!

Well that’s just factually inaccurate.

1. Which “ice age”? Dinosaurs in general didn’t evolve until after a few “ice ages”, and they were well extinct (well, except for birds) before the last one. 

2. Theropods didn’t arise until the Triassic period which is generally known to be HOT AND HUMID! 

3. With the exclusion of small specialized coelurosaurian theropod dinosaurs (which would lead eventually to modern day birds), large ones like this guy in his underwear here (haha) were very well extinct (see no. 1) as the last GLACIAL period (not ice age ugh) was during the Pleistocene (roughly 2,000,000 - 12,000 years ago). Large theropods died out 65,000,000 years ago sooooo….. No. Lol he (or she) hasn’t had any friends for much longer than what he (or she) says haha aww now it’s depressing even more! Lol

Note: my specialty is evolutionary and developmental biology, so if I’m wrong here, please let me know!

18 8 / 2014

Is Eating Behavior Manipulated by the Gastrointestinal Microbiota? Evolutionary Pressures and Potential Mechanisms
It would appear that the bacteria that lives within us may contribute to (control) our daily food intake and moods, that is, according to a new study published this week in the journal BioEssays. 

Microbes in the gastrointestinal tract are under selective pressure to manipulate host eating behavior to increase their fitness, sometimes at the expense of host fitness. Microbes may do this through two potential strategies: (i) generating cravings for foods that they specialize on or foods that suppress their competitors, or (ii) inducing dysphoria until we eat foods that enhance their fitness. We review several potential mechanisms for microbial control over eating behavior including microbial influence on reward and satiety pathways, production of toxins that alter mood, changes to receptors including taste receptors, and hijacking of the vagus nerve, the neural axis between the gut and the brain. We also review the evidence for alternative explanations for cravings and unhealthy eating behavior. Because microbiota are easily manipulatable by prebiotics, probiotics, antibiotics, fecal transplants, and dietary changes, altering our microbiota offers a tractable approach to otherwise intractable problems of obesity and unhealthy eating.


What I particularly find interesting is how the microbes influence the vagus nerve. They mention in the article that severing (or blocking) the vagus nerve in mice induced a considerable amount of weight lost, indicating that the microbes influence our predisposition to obesity to gain their desired nutrients. 

In combination of that, the microbes also seem to possess the ability to create neurochemicals that are analogous with mammalian hormones that are involved with mood and behavior. 

More than 50% of the dopamine and the vast majority of the body’s serotonin have an intestinal source. Many transient and persistent inhabitants of the gut, including Escherichia coli, Bacilluscereus, B. mycoides, B. subtilis, Proteus vulgaris, Serratia marcescens, and Staphylococcus aureus have been shown to manufacture dopamine. Concentrations of dopamine in culture of these bacteria were reported to be 10–100 times higher than the typical concentration in human blood 

The loss (or lack) of microbiota reduces the predisposition to obesity, hinting that a non diverse ecosystem of gut bacteria may be a factor in obesity. 

For example, mice that lacked the toll-like receptor TLR5 became obese and developed altered gut microbiota, hyperphagia, insulin resistance, and pro-inflammatory gene expression. 

Certain strains of probiotics on the other hand have been reported to reduce fat mass and improve insulin sensitivity and glucose tolerance, resulting in higher gut diversity. The reason a higher gut diversity is thought to lead to weight lost or the elimination of “food cravings” is due in large part to the increase competition and cooperation between the various species of bacteria, resulting in expenditure of their resources to manipulate their host. 

Obviously there is more to all of this than what i have chosen to write here and so I highly recommend giving this research a read and I’d love to hear varying opinions! 

Let me know what you think!

——————————-
SOURCES:
BioEssays
Science Daily
RESEARCH ARTICLE (without the annoying paywall)

Is Eating Behavior Manipulated by the Gastrointestinal Microbiota? Evolutionary Pressures and Potential Mechanisms

It would appear that the bacteria that lives within us may contribute to (control) our daily food intake and moods, that is, according to a new study published this week in the journal BioEssays

Microbes in the gastrointestinal tract are under selective pressure to manipulate host eating behavior to increase their fitness, sometimes at the expense of host fitness. Microbes may do this through two potential strategies: (i) generating cravings for foods that they specialize on or foods that suppress their competitors, or (ii) inducing dysphoria until we eat foods that enhance their fitness. We review several potential mechanisms for microbial control over eating behavior including microbial influence on reward and satiety pathways, production of toxins that alter mood, changes to receptors including taste receptors, and hijacking of the vagus nerve, the neural axis between the gut and the brain. We also review the evidence for alternative explanations for cravings and unhealthy eating behavior. Because microbiota are easily manipulatable by prebiotics, probiotics, antibiotics, fecal transplants, and dietary changes, altering our microbiota offers a tractable approach to otherwise intractable problems of obesity and unhealthy eating.

What I particularly find interesting is how the microbes influence the vagus nerve. They mention in the article that severing (or blocking) the vagus nerve in mice induced a considerable amount of weight lost, indicating that the microbes influence our predisposition to obesity to gain their desired nutrients.

In combination of that, the microbes also seem to possess the ability to create neurochemicals that are analogous with mammalian hormones that are involved with mood and behavior.

More than 50% of the dopamine and the vast majority of the body’s serotonin have an intestinal source. Many transient and persistent inhabitants of the gut, including Escherichia coli, Bacilluscereus, B. mycoides, B. subtilis, Proteus vulgaris, Serratia marcescens, and Staphylococcus aureus have been shown to manufacture dopamine. Concentrations of dopamine in culture of these bacteria were reported to be 10–100 times higher than the typical concentration in human blood

The loss (or lack) of microbiota reduces the predisposition to obesity, hinting that a non diverse ecosystem of gut bacteria may be a factor in obesity.

For example, mice that lacked the toll-like receptor TLR5 became obese and developed altered gut microbiota, hyperphagia, insulin resistance, and pro-inflammatory gene expression.

Certain strains of probiotics on the other hand have been reported to reduce fat mass and improve insulin sensitivity and glucose tolerance, resulting in higher gut diversity. The reason a higher gut diversity is thought to lead to weight lost or the elimination of “food cravings” is due in large part to the increase competition and cooperation between the various species of bacteria, resulting in expenditure of their resources to manipulate their host.

Obviously there is more to all of this than what i have chosen to write here and so I highly recommend giving this research a read and I’d love to hear varying opinions!

Let me know what you think!

——————————-

SOURCES:

BioEssays

Science Daily

RESEARCH ARTICLE (without the annoying paywall)

11 8 / 2014

11 8 / 2014

"In the way that skepticism is sometimes applied to issues of public concern, there is a tendency to belittle, to condescend, to ignore the fact that, deluded or not, supporters of superstition and pseudoscience are human beings with feelings, who, like the skeptics, are trying to figure out how the world works and what our role in it might be. Their motives are in many cases consonant with science. If their culture has not given them all the tools they need to pursue this great quest, let us temper our criticism with kindness. None of us comes fully equipped."

Carl Sagan (The Demon-Haunted World: Science as a Candle in the Dark / Ch. 17 pg. 298)