Thursday, July 31, 2014

The Smell of Fear: how baby rats learn fear from their mothers

Infants learning a variety of behaviours from their parents is an evolutionary advantage.  After all, if mom hid from that huge animal and survived, it's probably a pretty good thing to learn if you want to survive.  But apparently, learning is not only done through observation - especially since often, infant animals are born without a fully functional sense of sight or hearing.  A new study published in PNAS suggests that some behaviours that are absolutely crucial to survival, like fear, can be transmitted intergenerationally through smell.  Mothers release pheromones when they feel fear, and their offspring pick up on it, thus transferring the fear. 

Wednesday, July 30, 2014

Gut Microbe Composition Varies Between Sexes.

When the gut microbiota of vertebrates is disturbed (technical term dysbiosis), it can cause a disruption in crucial digestive processes, potentially leading to obesity, diabetes, and inflammation.  Months ago, I wrote about a study that found gut microbes responsible for regulating weight gain, and there is a growing interest in manipulating the gut microbiota of humans to treat diseases arising from dysbiosis.  As it turns out, gut microbes also behave differently in males and females vertebrates, even when diets are identical.  This new finding may encourage sex-specific nutritional treatments to diseases and improve human health.

Monday, July 28, 2014

The Human Genome Contains Fewer Functional Genes Than Previously Thought

It's been a over a decade since the completion of the human genome project, and yet we still know very little about how much of that DNA is actually functional.  We have 23 pairs of chromosomes, with a total of 3 234.83 Mbp (that's 3 234.83 million base pairs), of which it was previously believed that 80% encoded functional proteins.  But since scientists like to argue, the word "functional" became contentious, since its definition was not made clear and it depended on experimental design.  The argument was that functional genes needed to contribute biochemical significance.  A new open access study recently set out to determine how much of the human genome contains functional genes.

Sunday, July 27, 2014

Science This Week (July 21-27, 2014)

Toxoplasma gondii (aka the cat poop parasite) has been put to work delivering cancer drugs.

A LEGO microscope that really works!

And in other toys-turned-equipment news: bubble wrap can now be used as a cheap alternative to 96-well plates in assays.

Researchers have found evidence that T. rex hunted in packs.

A Danish scientist announced that his team was able to remove HIV viral particles from cells using anti-cancer treatments.  This news comes from the 20th International AIDS Conference in Australia, to which 6 people on flight MH17 were headed.

And the world's first HIV-killing condom has been approved.

A new gene was discovered that fights metastasis in lung cancer.

Why domesticated animals have those cute, floppy ears (spoiler: it's to make them look cuter - seriously)

Bats don't just use SONAR to find their way, they also use polarized light (and they're the first mammal known to do this!) (Open Access)

Apparently, standing up to pee influences prostate enlargement in men with Lower Urinary Tract Symptoms. (Open Access)

A video discussing a meta-analysis of GMO safety (See more GMO topics that I've previously addressed).

Speaking of GMOs, GM mosquitoes will soon be released in Brazil. (more here)

Science is for everyone!  A 12 year old boy just discovered a new genus of spiders.

Just to remind you all how important science literacy is.

Wednesday, July 23, 2014

6 Common Science Myths Debunked

My sister and I recently saw a preview for the new Scarlett Johansson movie, about a woman who becomes superhuman when she is able to access the 90% of her brain that is unused in all other humans.  I scoffed at that old myth, but my sister wasn't convinced that it is a myth.  This gave me the idea to look at some pervasive myths in science and medicine, and try to debunk them.  Here are the top 6 (started out as 5, but the cell phone one was too hard to resist) science myths many people have accepted as fact.

Tuesday, July 22, 2014

Measuring Epigenetic Changes in Individual Cells

There is so much DNA within a cell's genome that it has to be folded and packaged within the cell's nucleus, with the help of various proteins.  When it comes time to express genes, the DNA can be remodeled around the "helper" proteins, or small tags can be added - like a methyl or acetyl group.  This gives the transcription proteins easier or harder access to certain genes, thereby affecting which genes are expressed and which are not (technical term: epigenetics).  Your genome still contains all of its original genes, but doesn't always express them.  The pattern of methylation can also be passed on to offspring.  Typically, the measure of epigenetic modifications within a genome is measured using many cells whose DNA is pooled, but researchers from the UK have developed a new method for investigating these effects on development.  This technique is powerful enough to measure the epigenetic changes within the genome of a single cell.  This method has the potential to increase our understanding of embryonic development, and to enhance cancer, gene, and fertility therapies.  It could also reduce the use of animals in gene and cancer research.

Thursday, July 17, 2014

What it's Like to be a Woman in Science

As a scientist, a woman, and a feminist, I get really angry when people think the barriers keeping women out of science aren't real, or are self-imposed.  This morning, I read a post criticizing the idea that women and girls shy away from science because they're biologically predisposed to not like science.  Naturally, my brain exploded from infuriation at the original article, and at the comments, and that this isn't the first such article I read this week. I thought I'd share with you some of my personal experiences with being a woman in science, and why I left scientific research immediately after I got my PhD.  I'll also get into some of the myriad studies that have shown, time and time again, that there are VERY REAL barriers for women in science, particularly in academia, that go beyond having babies and/or not wanting to touch yucky stuff.

Game Theory Modeling Shows When Tumor Cells are Most Vulnerable

Cooperation between oxygen-poor cells (red)
and oxygen-rich ones (green). Source.
Increasingly, biologists are turning to other scientific fields to study the complexities of life.  Particularly, math and biology are becoming more and more intertwined as systems biologists attempt to model the properties of various systems, from metabolic pathways, to cells and tissues, to whole populations and ecosystems.  A new open access study out of John Hopkins Hospital used game theory, an economic model for studying strategic decision making, to identify cancer cell types that are more vulnerable to anti-cancer therapy.

Tuesday, July 15, 2014

Birds of a (Genetic) Feather Flock Together: How Genes Determine Human Friendship

That picture on the right is one of my favorite quotes about friendship, but a new study (and it's open access) points out that friendship might not actually be so random.  Friendship is a fundamental characteristic of being human, and genes are known to play a role in the formation and structure of friendship ties.  As it turns out, genes also play a role in deciding who we select as friends.  We share about 1% of our genes with our friends, and we don't find them at random.  Since we can't see their genes, we use our sense of smell to find them!

Monday, July 14, 2014

Yeast Study Shows That Cheaters Never Prosper - Except in Unchanging Environments

Yeast research. Source.
That old adage "cheaters never prosper" may actually turn out to be quite true when it comes to the evolution of the population.  This is especially the case in cooperative species, such as microbes (whoever thought microbes were so social?).  A recent open access study looking at colonies of yeast found that populations dominated by cheaters were more likely to face extinction than those dominated by non-cheaters.  That means that in highly social and cooperative species, evolutionary dynamics are influenced by selfish behavior. 

Friday, July 11, 2014

The Placenta: a Battleground in Sexual Dynamics

Sexual selection is a fun topic in biology because it explains the evolution of all kinds of non-functional, sometimes bizarre and counter-productive traits.  It is a form of natural selection in which the presence of a given trait allows individuals to out-reproduce others.  Secondary sexual traits include anything from the ornate feathers on peacocks and birds of paradise, antlers on stags, and even eye span in the stalk-eyed fly (yup, those are eyes at the end of those stalks, not antennae):

Basically, the ladies are choosy, so any male with a unique trait or the ability to grow/make one gets to mate.  In some cases when a trait gets to be too common (*cough* beards), they lose their appeal. 

Tuesday, July 8, 2014

The Problem With Science Journalism

Poor science journalism is irresponsible.  It misleads the public and policymakers.  It can lead to hysteria, public health crises, bad public policies, and can fund or defund research.  The major problem with science journalism is that these journalists are not scientists.  In fact, about 80% of them don't have a science degree.  So how can you spot bad science and avoid writing about it when you can't tell the difference between good science and bad science?

Monday, July 7, 2014

Carrying Therapeutic Cargo Using Engineered Red Blood Cells

Human red blood cells supported on a glass slide.
Red blood cells - Source

Red blood cells carry oxygen throughout your body, but could they be harnessed to carry more valuable payloads too?  That's what a team of scientists out of Cambridge, MA attempted to find out.  Red blood cells (RBC) are presumably great candidates for in vivo delivery of natural and synthetic compounds because they are distributed throughout the body, are biocompatible, have a half-life in humans of 120 days, have a high surface-to-volume ratio, and can be removed by the immune system if damaged.  But, and perhaps most importantly, they also lack nuclei, mitochondria, and genetic material when they mature.  That means that any modifications that are made to the DNA of RBC precursors is eliminated when they mature and lost their nuclei, and can't cause tumors or other abnormal growth after transfusion. 

Thursday, July 3, 2014

Making Good Quality Stem Cells Depends on the Reprogramming Method

Scanning electron micrograph of
human embryonic stem cells (source)
Stem cells offer an enormous promise in emerging cell transplantation therapies.  In theory, they could be used to replace any ailing cells, tissues, or organs in the human body.  In practice, however, available cell types have significant limitations.  For example, embryonic stem cells are considered the "gold standard", but are allogeneic (meaning they are derived from a genetically separate individual) and are occasionally the subject of ethical debates.  Researchers have instead opted for methods of turning adult somatic cells into stem cells, but these are susceptible to epigenetic and transcriptional abnormalities.  A research group from the U.S. looked at whether these abnormalities are intrinsic to somatic cell reprogramming methods.  They ultimately found that stem cells created using different methods produce different types of cells.

Wednesday, July 2, 2014

Plants Can Differentiate Between Sounds and Respond Accordingly

Gardeners have long been touting the positive effect of talking to their plants, which increases plant yield.  Exposing plants to music has also been shown to promote plant growth and development, but these types of experiments lack an ecological context.  For example, music contains such a wide range of frequencies, amplitudes, and fine-temporal patterns that are unlikely to be found in combination in nature.  In an open access study published today in Oecologia, a group of researchers examined the effect of more ecologically relevant sounds, like those from herbivores and other insects, on plant development.