This week, I've selected four posts:
1) Iddo Friedberg highlights some interesting research being done on quorum sensing, a form of bacterial intercellular communication.
Under certain conditions, bacteria can cooperate as a population to create biofilms, a "tangled matrix of polymeric substances that includes proteins, DNA and polysaccharides which can serve as tough physical barriers that are immune to attacks by many antibiotics and other bacteriocidal agents".
In most natural environments, association with a surface in a structure known as a biofilm is the prevailing microbial lifestyle. Surface association is an efficient means of lingering in a favorable microenvironment rather than being swept away by the current (Watnick & Colter, 2000).Iddo discusses a couple of articles on how bacterial “freeloaders” (organisms which do not contribute to the formation of these biofilms but benefit from it) do in these systems.
2) Next up is a nice post from Skeptic Wonder on a fascinating endosymbiotic relationship between an amoebae and a kinetoplastid called Perkinsela. Interestingly, this interaction appears to be "mutualistic as the host and the endosymbiont both die without each other" and it could have arisen from parasitizing off the same host.
The question remains: is Perkinsela now an 'organelle'?
3) Tissue invasion and metastasis are hallmarks of cancer. Cells from primary tumor masses can travel and colonize the same or different organ sites leading to the formation of secondary tumors. Importantly, these “metastases” are the cause of 90% of human cancer-related deaths (Nguyen et al., 2009). In general, metastasis is considered a late event in cancer progression, but Varun Sreenivasan over at Wissenschaft discusses recent evidence on the systemic dissemination of tumor cells even before the full establishment of the primary tumor, using a mouse model of breast cancer.
4) Mystery Rays from Outer Space directs our attention to a few cases of "transmissible tumors": “cases where tumors actually spread from their original host, to other individuals”. Vertically transmitted tumors (maternal–fetal transmission) are the main focus of this post.
In case you don’t find this noteworthy, keep in mind that:
“Tumors aren’t supposed to be able to spread in this way (i.e should not be transmissible), because they’re essentially foreign transplants — they should be rapidly rejected, as if they were, say, a skin graft between two random people.”
That's it for this week. Stay tuned for more MolBio Research Highlights!
Some of the articles discussed in this week's selected posts:
Diggle, S., Griffin, A., Campbell, G., & West, S. (2007). Cooperation and conflict in quorum-sensing bacterial populations Nature, 450 (7168), 411-414 DOI: 10.1038/nature06279
Czárán T, & Hoekstra RF (2009). Microbial communication, cooperation and cheating: quorum sensing drives the evolution of cooperation in bacteria. PloS one, 4 (8) PMID: 19684853
DYKOVA, I., FIALA, I., & PECKOVA, H. (2008). Neoparamoeba spp. and their eukaryotic endosymbionts similar to Perkinsela amoebae (Hollande, 1980): Coevolution demonstrated by SSU rRNA gene phylogenies European Journal of Protistology, 44 (4), 269-277 DOI: 10.1016/j.ejop.2008.01.004
Hüsemann, Y., Geigl, J., Schubert, F., Musiani, P., Meyer, M., Burghart, E., Forni, G., Eils, R., Fehm, T., & Riethmüller, G. (2008). Systemic Spread Is an Early Step in Breast Cancer Cancer Cell, 13 (1), 58-68 DOI: 10.1016/j.ccr.2007.12.003
Tolar J, & Neglia JP (2003). Transplacental and other routes of cancer transmission between individuals. Journal of pediatric hematology/oncology : official journal of the American Society of Pediatric Hematology/Oncology, 25 (6), 430-4 PMID: 12794519
References used in this post:
Watnick P, Kolter R (2000) Biofilm, city of microbes. J Bacteriol. 182(10):2675-9
Nguyen DX, Bos PD, Massagué J (2009). Metastasis: from dissemination to organ-specific colonization. Nature Reviews Cancer 9, 274-284