How Life Works

how life worksAssociate Professor of Biology James Morris, together with several faculty members from Harvard, has recently written a new textbook, titled Biology: How Life Works, a book that seems likely to become a standard for teaching introductory biology to college students.

According to Morris,

“The last 20 years or so have seen remarkable and exciting changes in biology, education, and technology.  With these in mind, we re-thought what an introductory biology textbook could be.  Introductory biology is a student’s first exposure to college-level biology.  We wrote a book that provides a solid base on which to build and treats biology not as a list of terms and facts to be memorized, but instead as a 21st century science that is compelling and relevant to students’ lives..”

Human evolution and barefoot running

Jim Haber writes:

Our speaker [in the Joint Biology/Neuroscience Colloquium at 4 pm  in Gerstenzang 121] on Nov 14 is Prof. Daniel Lieberman from Harvard.  He is the second of our Distinguished Biology Lecturers.  Dan is one of the world’s experts on human evolution and running (how our necks balance our stride, among other things) .  His interests have also made him a major advocate for barefoot running.


Here’s a summary:

Ever since the human lineage diverged from the African apes, hominins have been bipeds of some sort.  Comparative and fossil evidence suggest that the earliest hominins were capable, habitual bipedal walkers but were also adept at climbing trees.  At some point, however, hominins lost the ability to climb trees very well, and became superlative long distance runners.  Comparisons of human endurance running performance with other mammals show that we excel at speed, distance, and running in the heat. Further, human distance running capabilities far exceed those of any other primate, and they match or even surpass the best mammalian runners in hot conditions over very long distances.  The human body is thus replete with many adaptations that improve endurance running performance, and many of these adaptations first appear about two million years ago in the fossil record of the genus Homo.

The evolution of human running is also relevant from the perspective of evolutionary medicine.  Perhaps the most important legacy is that humans evolved to be physical active endurance athletes compared to other apes, which helps explain why an absence of physical activity is not only abnormal but also pathological.  Another interesting legacy of our evolution history is that since humans ran barefoot for most of the last two million years, the study of barefoot running provides an opportunity to study how natural selection adapted the human body to run, potentially offering insights on preventing injury.

Materials in Motion: Engineering Bio-Inspired Motile Matter

Life is on the move! Motion is ubiquitous in biology. From the gargantuan steps of an elephant to the tiniest single celled amoeba, movement in biology is a complex phenomenon that originates at the cellular level and involves the organization and regulation of thousands of proteins. These proteins do everything from mixing the cytoplasm to driving cell motility and cell division. Deciphering the origins of motion is no easy feat and scientists have been studying such complex behavior for quite some time. With biology as an inspiration, studying these complex behaviors provides insight into engineering principals which will allow researchers to develop an entirely new category of far-from-equilibrium materials that spontaneously move, flow or swim.

In a recent report in the journal Nature, a team of researchers from Brandeis University consisting of Tim Sanchez, Daniel T. N. Chen, Stephen J. DeCamp, Michael Heymann, and Zvonimir Dogic have constructed a minimal experimental system for studying far-from-equilibrium materials. This system demonstrates the assembly of a simple mixture of proteins that results in a hierarchy of phenomena. This hierarchy begins with extending bundles of bio-filaments, produces networks that mix themselves, and finally culminates in active liquid crystals that impart self-motility to large emulsion droplets.

Their system consists of three basic components: 1) microtubule filaments, 2) kinesin motor proteins which exert forces between microtubule filaments, and 3) a depletion agent which bundles microtubule filaments together. When put together under well-defined conditions, these components form bundled active networks (BANs) that exhibit large-scale spontaneous motion driven by internally generated active stresses. These motions, in turn, drive coherent fluid flows. These features bear a striking resemblance to a biological process called cytoplasmic streaming, in which the cellular cytoskeleton spontaneously mixes its content. Additionally, the system has great potential for testing active matter theories because the researchers can precisely tune the relevant system parameters, such as ATP and protein concentration.


The researchers also demonstrate the utility of this biologically-inspired synthetic system by studying materials science topics that have no direct biological analog. Under dense confinement to an oil-water interface, microtubule bundles undergo a spontaneous transition to an aligned state. Soft matter physics describes such materials as liquid crystals, which are the materials used to make liquid crystal displays (LCDs). These active liquid crystals show a rich variety of dynamical behavior that is totally inaccessible to their equilibrium analogs and opens an avenue for studying an entirely new class of materials with highly desirable properties.

Lastly, inspired by streaming flows that occur in cells, the researchers encapsulate the bundled active networks into spherical emulsion droplets. Within the droplet, microtubules again formed a self-organized nematic liquid crystal at the oil-water interface. When the droplets were partially squished between glass plates, the streaming flows generated by the dynamic liquid crystals lead to the emergence of spontaneous self-motility.

This research constitutes several important advances in the studies of the cytoskeleton, non-equilibrium statistical mechanics, soft-condensed matter, active matter, and the hydrodynamics of fluid mixing. The researchers have demonstrated the use of biological materials to produce biomimetic functions ranging from self-motility to spontaneous fluid flows using fundamentally new mechanisms. Additionally, the experimental system of bundled active microtubules is poised to be a model for exploring the physics of gels, liquid crystals, and emulsions under far-from-equilibrium conditions.

To see more videos from the Dogic lab at Brandeis University, check out their YouTube page.

Rodal to Receive NIH New Innovator Award

The NIH recently announced that Assistant Professor of Biology Avital Rodal will be a recipient of the 2012 NIH Directors New Innovator Award. The award allows new, exceptionally creative and ambitious investigators to begin high impact research projects. Granted to early stage investigators, candidates are eligible for the award for up to ten years after the completion of their PhD or MD. The award emphasizes bold, new approaches, which have the potential to spur large scientific steps forward. This year’s award was made to fifty-one researchers, and provides each with 1.5 million dollars of direct research funding over five years.

The Rodal lab studies the mechanisms of membrane deformation and endosomal traffic in neurons as they relate to growth signaling and disease. Membrane deformation by a core set of conserved protein complexes leads to the creation of tubules and vesicles from the plasma membrane and internal compartments. Endocytic vesicles contain, among other cargoes, activated growth factors and receptors, which traffic to the neuronal cell body to drive transcriptional responses (see movie). These growth cues somehow coordinate with neuronal activity to dramatically alter the morphology of the neuron, and disruptions to both endocytic pathways and neuronal activity have been implicated in neurodegenerative diseases such as amyotrophic lateral sclerosis and Alzheimer’s disease.

Dr. Rodal hopes to determine how neuronal activity affects the in vivo function and biochemical composition of the membrane trafficking machinery, by examining the transport of fluorescently labeled growth factor receptors in chronically or acutely activated neurons at the Drosophila neuromuscular junction (NMJ). Her group will combine these live imaging studies with a proteomic analysis of endocytic machinery purified from hyper-activated and under-activated neurons. By investigating the interplay between neuronal activity, membrane deformation, and receptor localization in live animal NMJs, she hopes to gain a better understanding of the strategies that healthy neurons employ to regulate membrane trafficking events, and provide new insight into specific points of failure in neurodegenerative disease.

Bite Sci-zed Videos

Alex Dainis ’11 (Biology / Film, Television and Interactive Media) explains and entertains in her “Bite SCI-zed” youtube videos about science.

Inga Mahler (1925–2011)

A grand lady and long-term friend of the life sciences at Brandeis has died. Inga Mahler succumbed on November 12, 2011 at age 86, after fighting pancreatic cancer for two years. As she wished, she died peacefully at home, lucid and joyous until near the end.

Inga quietly played a significant role in the life sciences at Brandeis for over a half century. Inga’s family escaped Germany and settled in the United States. After college, she became interested in microbiology, and while her anesthesiologist-husband Donald Mahler served in a MASH unit in Korea, she did research on dental (oral) bacteria. When her husband moved to the Boston area, she continued her interest in microbiology by entering the Biology graduate program at Brandeis. She received her Ph.D. in 1961 with Margaret Lieb, studying how the replication of one virus (T4rII) in Escherichia coli interfered with another virus (λ). She was proud to have been the first woman who received a doctorate in Biology from Brandeis.

Inga remained at Brandeis until she retired in 2007, working as a senior research scientist in the laboratories of several faculty members in Biology and Biochemistry, mostly studying problems using bacteria. She studied DNA repair in collaboration with Lawrence Grossman.  In the 1960s, she became the first person to isolate and characterize the DNA of the amoeba-flagellate protozoan Naegleria, in the laboratory of Chandler Fulton. In those days this was a major challenge because then-standard methods for isolating DNA did not work with organisms like Naegleria. She worked on bacterial and viral DNAs in the laboratories of Julius Marmur and Herman Epstein, in studies ranging from enhancing transformation of cells by DNA to studying genes involved in the biosynthesis of the amino-acid arginine. She then worked for some years in the laboratory of Harlyn Halvorson, mostly studying Bacillus, and there began to use the then-new techniques of genetic engineering, such as DNA cloning, as they became available. She loved doing research at the bench, and was always interested in challenges. She discovered and isolated bacteria resistant to mercury, and studied how they could become resistant to such a toxic substance. In her last project, she worked with Karl Canter in the Physics Department, where she studied bacteria called Magnetotactic Multicellular Prokaryotes that grow in permanent clumps which collectively move and behave as single organisms, and whose mobility is affected by magnetic fields. Inga made important contributions to each lab in which she worked, and she left a succession of influential publications that span from 1952 to 2005.

She preferred bench-work to other tasks, and never sought an independent position. Yet in each lab where she worked, she provided leadership that helped that lab thrive during her years there. She mentored many students, and befriended and helped hundreds of colleagues. While never herself seeking fame, she contributed greatly to the “fame” of Brandeis.

In her early years at Brandeis, she ran a Friday afternoon “Happy Hour” at which all of us in the life sciences would gather for a little gin and conversation at the “end” of our seven-day weeks. These were the teenage years of Brandeis, when the faculty and staff of Biology and Biochemistry were rapidly building a reputation for themselves and for Brandeis in the life sciences. We were also young then, and having a lot of fun. With much less funding pressure, we worked day and night for the joy of it. Happy Hour was but one of Inga’s many contributions that helped make the life sciences become strong so quickly in the formative days of Brandeis.

Inga was a grand and cultured woman with an amazingly versatile mind, direct and outspoken but invariably polite, who always showed great kindness to others. She also loved life, including fast cars and reading great numbers of books, especially mysteries. She and her husband Donald, whom she survived by two years, were accomplished scuba divers, and enjoyed many visits to the Caribbean.

Inga was fluent in German and French as well as English. She told a story about a visit to Marienplatz in Munich where she stopped to taste brandy-filled chocolates at an upscale Chocolatier. She enjoyed them so much she enthusiastically recommended them in three languages. In consequence, the storekeeper kept feeding her additional samples, since her multilingual endorsement brought customers into the store!

Above all, Inga made the lives of all around her better. Many of us she touched at Brandeis will miss her greatly. As she wrote in the acknowledgment of her thesis in 1961, “The author wishes to express her thanks to the Biology Department — graduate students, faculty and staff — for their continued helpfulness, kindness, and advice.” No one encompassed these generous traits more than Inga herself.

Chandler Fulton, Professor of Biology Emeritus

Protected by Akismet
Blog with WordPress

Welcome Guest | Login (Brandeis Members Only)