How cell membranes patch holes

Cell membranes of our muscle cells can get ripped when we exercise. Ack! But don't shy away from the gym or the great outdoors. Of course our cells have a way to repair the tiny holes. It happens all the time. But we haven't been quite sure how things got patched up. In this article, scientists were actually able to observe the repair of cell membranes of living cells in a living organism. To do this, they used a zebrafish embryo, which is tiny and mostly transparent. They tagged proteins with florescent proteins (a cool technique for seeing molecules which I'll blog about someday) which the researchers knew were involved in repair. Then they burned holes in the cell membrane with a laser and watched what happened under a microscope. Holes in a cell membrane with a laser - wow.

This was done by Prof. Uwe Strähle and Dr. Urmas Roostalu from Karlsruhe Institute of Technology (KIT) and Heidelberg University. Read more about what they observed in the article from Science Daily.

How Telomeres Incriminate Cells That Can't Divide

I've been writing a post about DNA, so when I came across an article about telomeres and cell division, I thought cool! Not only does this article have a great explanation of what telomeres are, but it describes the scientific process. Scientists at the Salk's Molecular and Cell Biology Laboratory under Jan Karlseder have been studying these telomeres and their involving in aging and cancer. Reading between the lines, you can just see how these scientists would observe the changes and try to determine what was happening and why, and further how it could help cancer patients.

So what are telomeres? They're the end caps of the long DNA strands that make up your chromosomes. Every time a cell divides, these end caps shrink just a little. When they're gone or too much DNA damage is detected, other proteins are released so the cell shuts down and dies. Cancer cells often reset these telomeres so that they keep on dividing. One of the most famous cases of this are the HeLa cells, from Henrietta Lacks a black woman who died of cervical cancer in the fifties. Her cells are still alive and have been used many, many studies that have resulted in cures for several diseases. I wonder if HeLa cells were used for this study? Unfortunately, her family has been given no compensation, though many biological companies are making lots of money of HeLa cell cultures. But I digress.

Wanna learn something cool? Go read the telomere article at Science Daily. I'll be posting mine on DNA soon.

Rudolph Ludwig Carl Virchow: cell theory and bioethics

Today, we take it for granted that we’re made up of cells. But it was only in the mid nineteenth century that scientists really began to understand this. Two obstacles stood in the way of understanding. The first was simple observation: without microscopes, no one could even see cells. The second was the prevalence of a theory, or group of theories called Vitalism. Scientists believed that there was a distinct difference between organic matter and non-organic matter, and part of this difference was a kind of life energy. But that’s a cool dead theory for another post.

Because of the entrenchment of Vitalism, it was still over a hundred years after the first cells were seen through a microscope before anyone really understood that they were the basic building blocks of all life. Several scientists were involved. One of them was an interesting fellow named Rudolph Virchow.

Virchow was a physician and later an anthropologist. He was remarkable not only for his insistence that medicine be based on observation and experimentation, but also for being a revolutionary with strong ethical convictions.

Born in Germany on October 13, 1821, Virchow started out life as the only child of a farmer. Early on he showed a love for the natural sciences. Because of his aptitude he was given a fellowship which paid for him to attend medical school.

Self confident almost to a fault, he regularly challenged his teachers. At one point as a student, he conducted several experiments to disprove the theories of his professors that the causes of phlebitis (inflammation of the vein) were in the fluids rather than the vein walls (the cellular structure).

He received his medical degree from the University of Berlin in 1843. A few years later, he was sent to investigate a typhus outbreak in a poor province of Prussia. Instead coming back with a few medical guidelines, as had been expected, he insisted that the cure for such epidemics was the freedom of the people. The outbreaks weren’t just from poor hygiene, but were caused by the abject poverty and illiteracy which were caused by the economic and political subjugation of the people. Public health required “full and unrestrained” democracy, and everyone should have a constitutional right to health care.

After that, he became a political activist, often campaigning for free democracy and the equal treatment of peoples. And he firmly held fast to that ideal, even turning down noble status which was offered later in life in honor of his scientific achievements.

His political activism got him booted as a faculty member at his medical school. Fortunately, this allowed him to spend more time in the laboratory. It was during this period that he studied cells. The fact that all living things were made of cells had already been established by Matthias Jakob Schleiden and Theodor Schwann. But these scientists still believed that cells might form by crystallizing or some other kind of precipitating process. As well, they faced a great deal of opposition from the vitalists. Once again, going against the norm, Virchow agreed with the observations of Schwann and Schleiden. But instead of a kind of spontaneous generation of cells, Virchow observed cells dividing under the microscope and developed the theory that all cells come from other living cells by cell division. He popularized the saying “Omnis cellula e cellula”. His focus on cells was in pathology on how they lead to disease.

He combined his love of science and medicine with his insistence one the standard of equality for all men his whole life. In his later years he joined the city council in Berlin, working with the government to improve public health. He was one of the first to put forth socioeconomic and political factors as the source for many predispositions for diseases. And when he later became interested in anthropology, what he did was to gather data which disproved the then popular notion that people of Aryan or Nordic descent were superior to others. He proclaimed that medicine was the highest form of human insight and the mother of all sciences.   He died in 1902, after a life which moved medicine forward towards being evidence based and established a foundation for bioethics.