I defended my doctorate degree in Medical Biosciences - Biochemistry in October 2016 at the department of Anatomy, Physiology and Biochemistry at SLU. I have during my PhD studies deepened my knowledge in biochemistry, protein biochemistry, cell biology and histology. In more detail, I studied the molecular mechanisms of spider silk formation and developed a method to spin artificial spider silk!
My research at SLU
Spider silk is one of the toughest materials known to man, and has been used in traditional medicine for wound healing. It has also been shown to be well tolerated when implanted into living tissue. These extraordinary properties make spider silk a very attractive material for use in regenerative medicine. For that purpose, spider silk has been studied extensively the last decades. However, no one has been able to show the details of how spiders spin silk. During my PhD project I studied the molecular mechanisms of the spider silk production system, with the aim of producing a biomimetic spinning device for artificial spider silk.
Photo of a major ampullate gland from the golden orbweaving spider Nephila clavipes. Photo: Marlene Andersson
Spider silk proteins that make up the spider silk are produced in abdominal glands of spiders. The gland that I focus on in my project is the major ampullate gland (see above), which is the source of the dragline silk. We have shown that the spider silk proteins change their conformation in response to a very broad pH gradient that is present along the gland. By mimicking this pH gradient, we can spin artificial spider silk that mimics natural spider silk.
Artificial spider silk fibers spun in the lab. To the left: A fiber exiting the spinning device. Middle: A fiber nest collected in aqueous buffer. To the right: Fibers collected in a dry state on a frame. From protein purified from one liter of bacterial culture, we can spin one kilometer of silk fiber. Photos: Marlene Andersson
Andersson, M., Jia, Q., Abella, A., Lee, X-Y., Landreh, M., Purhonen, P., Hebert, H., Tenje, M., Robinson, C. V., Meng, Q., Plaza, G.R., Johansson, J., Rising, A. (2017) Biomimetic spinning of artificial spider silk from a chimeric minispidroin. Nature Chemical Biology. DOI: 10.1038/nchembio.2269.
Landreh, M., Andersson, M., Marklund, E.G., Jia, Q., Meng, Q., Johansson, J., Robinson, C.V., Rising, A. (2017) Mass spectrometry captures structural intermediates in protein fiber self-assembly. Chemical communications. DOI: 10.1039/C7CC00307B
Andersson, M., Johansson, J., Rising, A. (2016) Silk Spinning in Silkworms and Spiders. International Journal of Molecular Sciences DOI: 10.3390/ijms17081290
Domigan, L.J.*, Andersson, M.*, Alberti, K.A., Chesler, M., Xu, Q., Johansson, J., Rising, A., Kaplan, D.L. (2015) Carbonic anhydrase generates a pH gradient in Bombyx mori silk glands. Insect Biochemistry and Molecular Biology. DOI: 10.1016/j.ibmb.2015.09.001
Andersson, M., Chen, G., Otikovs M., Landreh, M., Nordling, K., Kronqvist, N., Westermark, P., Jörnvall, H., Knight, S.D., Ridderstråle, Y., Holm, L., Meng, Q., Jaudzems, K., Chesler, M., Johansson, J., Rising, A. (2014) Carbonic Anhydrase Generates CO2 and H+ That Drive Spider Silk Formation Via Opposite Effects on the Terminal Domains. PLoS Biology DOI: 10.1371/journal.pbio.1001921
Kronqvist, N., Otikovs, M., Chmyrov, V., Chen, G., Andersson M., Nordling, K., Landreh, M., Sarr, M., Jörnvall, H, Wennmalm, S., Widengren, J., Meng, Q., Rising, A., Otzen, D., Knight, S. D., Jaudzems, K., Johansson, J. (2014) Sequential pH-driven dimerization and stabilization of the N-terminal domain enables rapid spider silk formation. Nature Communications. DOI: 10.1038/ncomms4254
Andersson, M., Holm, L., Ridderstråle, Y., Johansson, J., Rising, A. (2013) Morphology and composition of the major ampullate gland and dragline silk. Biomacromolecules DOI 10.1021/bm400898t
Artificial spider silk fibers rolled up onto spools. Photo: Marlene Andersson
Want to know more?
Watch a four minute popular scientific presentation of my research in Swedish (winning presentation in Uppsala Forskar Grand Prix 2016).
Interview in Vetenskapsradions veckomagasin 2017
Radio interview (in Swedish), SR Uppland 2017
Interview by SVT Uppland, 2017
Scientists have finally figured out of to spin artificial spider silk the way spiders do, Forbes.com 2017
De spinner konstgjord spindeltråd, forskning.se 2017
Watch a three minute popular scientific presentation of my research in English (part of the Research Grand Prix contest at SLU 2015)
Mitchell Chesler, Dept. of Neurophysiology, Langone Medical Center NYU
Maria Tenje, Dept. of Engineering Sciences, Division of Microsystems Technology, UU
Organizer of seminar series for PhD students at the VH faculty.
Teaching on the course: Biomedicinsk baskurs for veterinary students and Djurens Biologi 1
Part of the VH PhD student council, student representative for AFB