Researchers have found a fossil of a female mosquito embedded in shale sediments in Montana. The abdomen of the mosquito is bloated with blood that is believed to be almost 46 million years old. Even though the researchers say the DNA in the blood has long since disintegrated, there are still large traces of iron and porphyrin, both of which make up hemoglobin.
So unfortunately, they can’t extract the DNA and use it to grow dinosaurs. Bummer. I wanted to ride a pterodactyl. But still. Pretty cool.
Here is the link to the article on nature.com
I know that the majority of you are pre-med and some of you might be headed toward a career in surgery. My father was a pathologist and one of his important tasks was to perform frozen sections on surgical specimens from patients on the surgery table to determine if the surgeon had excised past the margins of the tumor. When I was a teenager I would sometimes accompany him to the lab if he had a call on a saturday. The procedure is fairly simple, the tissue is placed on a metal post, covered with a viscous gel matrix, placed in a cryostat to freeze and then sections were cut from the frozen block using a microtome in the cryostat. the sections are then fixed to a glass slide and stained before the pathologist analyzes the samples to call back to the surgical suite to tell the surgeon whether (s)he needs to excise more or not. The problem is that this takes at least 20-30 minutes for each sample, all the while the patients are sitting on the table under anesthesia and the surgical team is just waiting.
I bring this up because earlier this week I saw a feature in Science that a company has developed a ‘smart’ scalpel, the iKnife, that can detect whether it is cutting cancerous or normal tissues. The scalpel can essentially sniff whether or not cancerous tissue is being cut. It does this by using a cauterizing (heated) blade that volatilizes compounds from the cells like phospholipids, metabolites, etc. Then a small port near the blade sucks in that smoke and volatile material and it is analyzed by a mass spectrometer. The pattern of molecules can be used as biomarkers to discriminate healthy tissue from cancer tissue. Pretty cool stuff!
As I was reading articles on the Tropical Fish Hobbyist website, I like keeping fish weird I know, I came across an interesting article. I have had many different fish over the years ranging from simple freshwater fish, to jellyfish or lion fish but I have never heard of Mycobacterium in aquariums! Mycobacteria usually are not pathogenic to humans, except for a few such as tuberculosis and leprosy, so this was an interesting find since some of us are working with mycobacteria. M. marinum can be found in any type of tank (freshwater, saltwater, and brackish) but luckily are rare infections to contract.
M. marinum infections can be pretty difficult to diagnose considering that there are few doctors that know about the various infections originating in the aquarium; also the fact that M. marinum has an incubation period of four weeks doesn’t help. The bacteria gains entry into the body by small cuts that are exposed to the infected water. Once inside the bacteria are quickly phagocytosed by macrophages, such phagocytosed material is normally degraded in lysosomes; however, mycobacteria resist lysosomal degradation and somehow manage to survive and even multiply within macrophage phagosomes! In an effort to contain the infection these macrophages clump together to form granulomas, which are mainly found on the superficial layers of the skin in an M. marinum infection.The bacteria gains entry into the macrophages via receptor mediated phagocytosis and certain plasma membrane cholesterol recognition. Certain antibiotics deprive the macrophages of this cholesterol so that the mycobacteria have no means of entry. This inhibition of uptake is specific for mycobacteria, as other microorganisms can still enter cholesterol-depleted macrophages.
This bacterial infection isn’t as virulent as tuberculosis, but can be pretty annoying as it can persist for one hundred and sixty days on average! So next time when you’re fumbling around in you’re aquarium, hopefully I am not the only one who does, look for cuts on your hands before putting them in the tank, or else you might contract a mycobacteria infection! Just thought you’d like to know!
So I was looking on my FaceBook feed and noticed an interesting feature from Smithsonian Magazine about women in science. In the biological sciences the proportion of male and female students is about equal through undergraduate and graduate study. Later on there are far fewer women in mid level and senior positions. Why is this the case? I do not know for sure, but I thought I would share how women scientists have shaped my development into a scientist and teacher.
The greatest impact on my career path was made by Mary Beckerle. She is a very prominent cell biologist who currently is director of the Huntsman Cancer Institute at the University of Utah, and is a past president of the American Society for Cell Biology. She has an interesting lecture on the cell biology and genetics of cancer at the iBioseminars website. When I was a Junior I took her advanced cell biology course. One day in class she announced that she had an opening for an undergraduate research assistant in her laboratory. I applied for the position, but I was not offered the job. Not being content with that I went back to her and begged, literally begged, to join her lab even without pay. She still said no, but then directed me to two new faculty that might have positions available. One studied the microtubule cytoskeleton in Xenopus (African clawed frog) and the other studied the polarization of brown algal zygotes in response to light. My main interest through college was in cell and neuro biology; I really liked the electrophysiology labs from neurobiology class. The research in Darryl Kropf’s lab was investigating the ionic basis for a small electrical current that flows through the zygote as the new developmental axis is established. Therefore, I was able to apply my interest in electrophysiology to study these small algal zygotes, thus beginning my interest in plant cell biology. So I have Dr. Beckerle’s rejection to thank for my current research interests.
After working with Darryl for a few years I applied to graduate school and chose to go to Purdue University. It is common in many graduate programs that first year students do rotations in a few labs that they might be interested to join. One of the labs I chose to do a rotation in was with Jody Banks. She is a wonderful geneticist and is, in fact, an academic granddaughter of one of the people featured in the article, Barbara McClintock. Jody studies the genetics of ferns and other lower plants. At the time I was working in her lab she had just published a really elegant genetic model for the sex determination of the gametophytes in the fern Ceratopteris. Working with Jody made me realize that I don’t have what it takes to really think like a geneticist so, although I lover her dearly, I did not join her lab. She was recently featured on NPR for her role in leading the sequencing of a primitive plant called a spike moss, which are believed to be among the oldest vascular plants. The story was called “Decoding the Platypus of the Plant Kingdom“, give it a listen it’s interesting stuff.
Finally that brings us to Baylor. In the normal training of scientists in the US the main focus, well essentially the only focus, is on productive research through graduate school and postdoctoral study. Then all of these well trained scientists start applying for positions at universities, which requires them now to TEACH. Well, we have had little or no experience teaching so it’s like being thrown in the deep end not knowing how to swim. We thrash around at first trying to figure out how to teach our first course, emulating the teachers that most greatly impacted us, but it is impossible to imitate another we have to find our own path. That is where Dr. Adair comes in. She has been teaching for many more years than me and has a more formal background in teaching. She cares deeply about teaching her students the best she possibly can is is constantly researching the best practices for teaching and learning. My association with her has had a profound impact on the way I approach my teaching. You should feel fortunate that Dr. Adair spearheaded the application for the NGRI, I sure do!
So there you have it 3 women scientists that have had major impacts on the progression of my career. So who influences and inspires your future?
Well those wacky physicists are at it again. Using super accurate optical clocks, which “tickle” single aluminum ions in an elaborate trap, they have measured differences in the passage of time just 1 meter apart in the earth’s gravitational field. Effectively this means that your head is experiencing time faster than your toes. Granted over an average lifetime the difference is less than 100 picoseconds, but it is remarkable that scientists can make such precise measurements!
The original story is here.
I have always been a little intrigued by the processes that regulate how and where membranes bud or fuse or invaginate. Some of my research has touched upon this topic because unlike most secreted proteins, the endosperm storage proteins I study never exit the ER in vesicles, but are retained in highly specialized protein bodies. Therefore in my advanced cell biology course I spend a lot of time talking about the sophisticated regulation that cells have evolved to control which membrane-bound compartments go where in the cell. If you look at it as analogous to a train, bus or airplane, each passenger has a ticket that must be verified by an agent and then the carrier takes off for the final destination. A bus, in particular, usually has a visible sign on the front marking where the final destination is. The process is amazingly similar in cells. Proteins (passengers) with a specific structure (ticket) are recognized by receptors (agents), loaded on specific a “bus” called a vesicle and transported on cytoskeletal highways to the correct destination (Lysosome, golgi, endosome, plasma membrane, etc.). In the cell each “station” and “bus” are painted with specific types of phosphoinositide lipids that in association with specific receptor proteins ensure that the transportation system runs smoothly.
Why did I just pop out and describe this complex regulation? Well, other than the fact we will begin to discuss membranes, membrane transport and membrane trafficking soon: the most recent “Editors Choice” email from Science magazine highlighted a really interesting article that, for the first time, studied the process of endocytosis in vitro! Why is this exciting? Now that these investigators have established a cell-free system they can bit by bit reduce the system to the necessary players. And why is this important? There are many diseases associated with improper transport and processing of proteins in cells and tissues and as we identify the critical players therapies can be developed. In vitro investigations of transport between the ER and Golgi were critical for understanding how the whole bus station and transportation network were regulated and organized.
A great series of lectures on the topic are given by HHMI investigator Randy Scheckman on the iBioseminars site. I think Scheckman is a serious contender for a Nobel Prize in medicine within the next few years.