Mary Lynne Perille Collins Professor B.A., Emmanuel College 1971 Ph.D., Rutgers University 1976 Postodoctoral Fellow NYU School of Medicine 1976-1980	Office: Lapham 440 Phone: 414-229-5298 CGLS:414-382-1727 FAX: 414-229-3926 Email: mlpcolli@uwm.edu Electronic Reserve Materials:
Microbial Physiology

Research Interests

Membranes form the structural and functional limits of the cell. Membranes separate the cellular contents from the environment and are the site of many essential activities such as energy transduction and the initiation of responses to environmental stimuli. My research interests center on the molecular events involved in membrane development. My lab is studying this in two model systems - phototrophic bacteria and methanotrophic bacteria. Unlike most other bacteria, both of these groups form an intracytoplasmic membrane (ICM). In both cases the formation of this membrane is affected by environmental conditions thus allowing laboratory manipulation of membrane formation. Phototrophic bacteria, such as Rhodospirillum rubrum, use light as a source of energy. The photosynthetic apparatus is housed in an ICM. Using biochemical, immunochemical, and ultrastructural approaches, work from my laboratory has demonstrated that the ICM and cytoplasmic membrane are continuous and that when triggered by environmental stimuli, the ICM arises from invagination and differentiation of the cytoplasmic membrane. We have provided evidence that the cytoplasmic membrane is differentiated into functional domains; the role of these domains in ICM biogenesis is under study. We have cloned the genes encoding the pigment-binding proteins of the photochemical complexes, constructed mutants, and evaluated the effects of these mutations in vivo. Knockout mutants lacking protein components of the photochemical complexes do not form ICM; ICM formation is restored by complementation in trans. These studies demonstrate that the proteins of the photochemical components are required for ICM formation. This leads to the hypothesis that insertion of these proteins in the membrane is a stimulus for membrane proliferation. Because mutants that lack the pigment-binding proteins do not make ICM but retain the capacity to do so, these mutants have "excess capacity" for the incorporation of membrane proteins. This makes them excellent hosts for the production of heterologous membrane proteins. We are studying the assembly of membrane proteins in R. rubrum - this includes both the photochemical complexes and heterologous membrane proteins expressed in R. rubrum mutants. Methanotrophic bacteria use methane as a sole source of carbon and energy. The ICM of methanotrophs has a role in the metabolism of one carbon compounds. This is evidenced by the localization of enzymes of methane metabolism to the ICM by immunoelectron microscopy. Formation of the ICM is governed by environmental conditions - specifically copper availability. Methanotrophs have attracted a great deal of interest because as methane consumers, they serve as a methane sink in the environment. In addition, because some of the enzymes of methane metabolism show a very broad substrate specificity, methanotrophs have significant potential in biotechnology including bioremediation. We have developed PCR-based methods to detect methanotrophs and other bacteria (including pathogens) in environmental samples.

Patents

Collins, M. L. P. Method, vector and system for expressing polypeptides. PCT/US09/30564, patent pending. Collins, M. L. P. and Y. Cheng. 2004 and 2005. Host/vector system for expression of membrane proteins. U.S. patents 6,680,179 and 6,951,741.

Selected Publications

Benson, J. A., K. A.. Fode-Vaughan, and M. L. P. Collins. 2004. Detection of Helicobacter pylori in water by direct PCR. Lett. in Appl. Microbiol. 39: 221-225. Fode-Vaughan, K. A., J. S. Maki, J. A.Benson, and M. L. P. Collins. 2003. Direct PCR detection of Escherichia coli O157:H7. Lett. Appl. Microbiol. 37: 239-243. Brantner, C.A., C. C. Remsen, H. A. Owen, L. A.Buchholz, and M. L. P. Collins. 2002. Intracellular localization of the particulate methane monooxygenase and methanol dehydrogenase in Methylomicrobium album BG8. Arch. Microbiol. 178: 59-64. Abstract Fode-Vaughan, K. A., C. F. Wimpee, C. C. Remsen and M. L. P. Collins. 2001. Detection of bacteria in environmental samples by Direct PCR without DNA extraction. BioTechniques 31: 598-607.Online Source Lemos, S., M. L. P. Collins, S. S. Eaton, G. R. Eaton, and W. E. Antholine. 2000. Comparison of EPR-visible Cu2+ sites in pMMO from Methylococcus capsulatus (Bath) and Methylomicrobium album BG8. Biophys. J. 79: 1085-1094. Online Reprint Cheng, Y. S., C. A. Brantner, A. Tsapin, and M. L. P. Collins. 2000. Role of the H protein in assembly of the photochemical reaction center and intracytoplasmic membrane in Rhodospirillum rubrum. J. Bacteriol. 182: 1200-1207. Online Reprint Brantner, C.A., L. A. Buchholz, C. C. Remsen, and M. L. P. Collins. 2000. Isolation of intracytoplasmic membrane from the methanotrophic bacterium Methylomicrobium album BG8. Curr. Microbiol. 40: 132-134. Online Source Yuan, H., M. L. P. Collins, and W. E. Antholine. 1999. Type 2 Cu2+ in pMMO from Methylomicrobium album BG8. Biophys. J. 76: 2223-2229. Online Reprint Cheng, Y.S., J. L. Halsey, K. A. Fode, C. C. Remsen, and M. L. P. Collins. 1999. Detection of methanotrophs in groundwater by the PCR. Appl. Environ. Microbiol. 65: 648-651. Online Reprint Yuan, H., W. E. Antholine, and M. L. P. Collins. 1998. Concentration of Cu, EPR-detectable Cu, and formation of cupric-ferrocyanide in membranes with pMMO. J. Inorganic Biochem. 72: 179-185. Abstract Brantner, C. A., L. A. Buchholz, C. L. McSwain, L. L. Newcomb, C. C. Remsen, and M. L. P. Collins. 1997. Intracytoplasmic membrane formation in Methylomicrobium album BG8 is stimulated by copper in the growth medium. Can. J. Microbiol. 43: 672-676. Yuan, H., M. L. P. Collins, and W. E. Antholine. 1997. Low-frequency EPR of the copper in particulate methane monooxygenase from Methylomicrobium albus BG8. J. Amer. Chem Soc. 119: 5073-5074. Online Reprint Buchholz, L.A., J. V. Klump, M. L. P. Collins, C. A. Brantner, and C. C. Remsen. 1995. Activity of methanotrophic bacteria in Green Bay sediments. FEMS Microbiology Ecology 16: 1-8. Lee, I. Y. and M.L.P. Collins. 1993. Identification and partial sequence of the bchA gene of Rhodospirillum rubrum. Current Microbiol. 27: 85-90. Fassell, T. A., L. A. Buchholz, M.L.P. Collins, and C. C. Remsen. 1992. Localization of methanol dehydrogenase in two strains of methylotrophic bacteria detected by immunogold labeling. Appl. Env. Microbiol. 58: 2302-2307. Abstract Hessner, M. H., P. J. Wejksnora, and M. L. P. Collins. 1991. Construction characterization, and complementation of Rhodospirillum rubrum puf region mutants. J. Bacteriol. 173: 5712-5722. Collins, M. L. P., L. A. Buchholz, and C. C. Remsen. 1991. The effect of copper on Methylomonas albus BG8. Appl. Env. Microbiol. 57: 1261-1264.