In the past, it was thought that a fetus was sterile while in the womb and that a baby’s first food, breast milk, was also free of microbes. Recent research turns this idea on its head as Beth Skwarecki presents in a fascinating DoubleXScience post.
“Babies are born without a fully developed intestinal mucosa, and need interaction with bacteria to basically jump start their immune system,” says Lisa Funkhouser, who co-authored a paper with Seth Bordenstein last month on the many ways mothers across the animal kingdom transmit microbes to offspring.
What’s most fascinating about the microbes in breast milk and those that a fetus harbors before birth is where they originate. The idea is still in its, um, infancy, but evidence is accumulating that cells in the bloodstream pick up microbes from the intestine and transport them to destinations in milk-producing breast tissue … and across the placenta to the developing fetus.
These microbes make up the ground level floor of a baby’s gut ecosystem–preparing the immune system for future invaders. There’s a ton of interesting science jam-packed into this article–check it out.
SciStarter helps citizen scientists discover new projects:SciStarter is an incredible database of science projects that anyone can participate in. Read more about the website and some of the projects it includes here.
Salmonella typhimurium Photo: Volker Brinkmann, Max Planck Institute for Infection Biology, Berlin, Germany
Engineering self-destructing Salmonella to make better vaccines: Researchers at Arizona State University are doing an amazing thing. Wei Kong and others in Roy Curtiss’s lab are engineering Salmonella to turn it into a delivery system for DNA vaccines. They recently published their advances in the Proceedings of the National Academy of Sciences. Hypothetically such vaccines could be used against not just viruses but also fungal or parasitic infections and could also be a key defense against bioterrorism. Read more here.
Pregnant woman at a WIC clinic in Virginia. Photo by Ken Hammond (USDA).
States are slashing Medicaid benefits as an attempt to get ballooning health care costs under control. As the New York Times reports, dental coverage for adults is often one of the first items on the chopping block. Now, in about half of the states, dental coverage from Medicaid will only cover pain relief and emergency services. Time will tell if shifting dental care to already overburdened ERs will actually save states money. A study looking at pediatric patients with dental problems found reimbursement rates from emergency rooms were ten times the predicted cost of preventative care. There is already a shift toward more patients using the ER for dental emergencies. From 2006 to 2009 the number rose by 16%. This is a prime example of an unintended consequence.
But when I read the NYTimes piece, I thought of another unintended consequence–one that could impact future generations. This is because I knew there was an association between gum disease and preterm birth (probably something that stuck in my brain from all the reading I did while pregnant). In fact, a pregnant woman with periodontal gum disease is 4.3 times more likely to have a preterm baby than is a healthy pregnant woman. [In one sad case, the death of a stillborn baby was linked to bacteria from the mother’s gum disease]. One study found that treatment of pregnant women with gum disease prevented this adverse result–but only if the treatment was successful at getting rid of the disease. Some states offer dental coverage for pregnant women. But many others do not, and as the study cited above indicates, this coverage may be too late for preventing early births. Preterm birth is a risk factor for a host of issues–from increased infant mortality to cerebral palsy to developmental delays.
The Affordable Care Act requires insurers to cover dental care for kids and also includes funds for opening more dental clinics and for public awareness campaigns about preventing oral illnesses. The ACA does not, however, force insurers to offer dental coverage to adults. According to a Senate report from earlier this year, 42% of Americans —130 million people–don’t have any form of dental insurance. Given these numbers, it may be unsurprising that a recent study found that over 47% of adult Americans have some form of periodontal disease. If we want to prevent all of the complications associated with gum disease (and the health care dollars associated with these problems), we should be expanding dental insurance for preventative care. And such coverage shouldn’t be limited to children and women of childbearing age. This is blatantly obvious when we consider evidence from even more studies, which show that gum disease puts adults with poor dental health care at risk for other conditions, including heart attacks and pancreatic cancer. Now I really need to schedule that cleaning…
Spotted hyena in Kenya (photo credit: Joanna Goldby)
Spotted hyenas live in groups of 40-80 animals. These groups called ‘clans’ are complex and contain multiple subgroups that can be spatially distinct. Throughout the day different subgroups form and break up over and over again. Yet individual clan members are very successful at recognizing other members of their clan. This is important as hyenas are quite hostile to intruding hyenas from other groups.
How does a hyena know whether another hyena is an intruder? Besides visual and vocal cues, hyenas also do something called “pasting” which involves rubbing their anal scent glands against grass stalks and leaving a strong odor trail (humans can detect the smell more than a month after the pasting). A recent study published in Scientific Reports found that odor-producing bacteria from hyenas from the same group are more genetically related than bacteria from hyenas from different groups, and that “pasting” may be one method for how hyenas announce their clan identities (in fact, members of the same clan often paste on top of one another–presumably as a way to mix and share their “clan scent”). This research, performed by scientists at Michigan State University, is the first to provide evidence that hyenas harbor clan-specific bacteria in their scent glands.
While most people think bacteria only make us sick, some bacteria actually helps the human body preform important jobs. And, a new study shows that bacteria can strengthen our immune systems and get us ready to fight more dangerous infections.
