Bio

Bio


Paula Welander received her undergraduate degree at Occidental College in Los Angeles. She pursued her PhD studies at the University of Illinois at Urbana-Champaign studying methanogenesis with Bill Metcalf. She was a postdoc with Dianne Newman and Roger Summons at MIT studying hopanoid and sterol function in bacterial species. She joined the Stanford faculty in 2013.

Academic Appointments


  • Assistant Professor, Environmental Earth System Science
  • Assistant Professor (By courtesy), Biology

Administrative Appointments


  • NASA Astrobiology Postdoctoral Fellow, Massachusetts Institute of Technology (2012 - 2012)
  • Research Scientist, Massachusetts Institute of Technology (2011 - 2012)
  • NSF Minority Postdoctoral Fellow, Massachusetts Institute of Technology (2008 - 2011)
  • National Science Foundation Graduate Research Fellow, University of Illinois at Urbana-Champaign (2002 - 2005)
  • Graduate College Fellow, University of Illinois at Urbana-Champaign (2001 - 2007)
  • Research Associate I, Beckman Research Institute, City of Hope (1999 - 2001)
  • Research Assistant I, California Institute of Technology (1998 - 1999)

Honors & Awards


  • Terman Fellow, Stanford University (2014)
  • Gabilan Faculty Fellow, Stanford University (2013)
  • NASA Astrobiology Postdoctoral Fellowship, NASA Postdoctoral Program (2012)
  • OGD 2010 Best Paper Award, Geochemical Society (2011)
  • NSF Minority Postdoctoral Research Fellowship, National Science Foundation (2008)
  • Mame Shiao Debbie Award, University of Illinois at Urbana-Champaign (2006)
  • Outstanding Teaching Assistant, University of Illinois at Urbana-Champaign (2005-2006)
  • Recipient, Gordon Conference Minority Student Travel Grant (2003)
  • NSF Graduate Research Fellowship, National Science Foundation (2002)
  • Graduate College Fellowship, University of Illinois at Urbana-Champaign (2001)
  • Recipient, Declined, NIH MCB Training Grant Fellowship, University of Illinois at Urbana-Champaign (2001)
  • Recipient, Howard Hughes Medical Institute Undergraduate Research Grant (1998)
  • Undergraduate Research Academic Support Program Grant, Occidental College (1997)
  • Fellow, Richter Fellowship (1997)
  • Recipient, Cal Grant (1995 – 1998)

Boards, Advisory Committees, Professional Organizations


  • Editorial Board Member, Geobiology Journal (2014 - Present)
  • Member, American Geological Union (2013 - Present)
  • Member, American Society of Microbiology (2002 - Present)

Professional Education


  • Ph.D., University of Illinois at Urbana-Champaign, Urbana, IL, Microbiology (2007)
  • M.S., University of Illinois at Urbana-Champaign, Urbana, IL, Microbiology (2003)
  • B.A., Occidental College, Los Angeles, CA, Kinesiology (1998)

Research & Scholarship

Current Research and Scholarly Interests


Research
I am a microbiologist with interests in understanding the biosynthesis and physiological function of “molecular fossils” or biomarkers in extant bacteria. Biomarker signatures in ancient rocks have been used to reconstruct important events in the Earth’s past, such as the first appearance of major groups of organisms, the catastrophic loss of biodiversity and the evolution of cyanobacteria and oxygenic photosynthesis. Despite the significant implications biomarker studies have on our interpretation of microbial evolution and of the Earth’s ancient environment, our understanding of the phylogenetic distribution and physiological function of most of these molecules in modern bacteria is quite limited. My research utilizes a combination of bioinformatics, microbial genetics, physiology, and biochemistry to address three general questions that can be applied to any biomarker: 1) what is its phylogenetic distribution in modern bacteria? 2) what are its physiological roles in modern bacteria? 3) what is the evolutionary history of its biosynthetic pathway?

Teaching
My teaching will focus on two of my main interests: 1) microbial physiology and metabolism and 2) how molecular biosignatures are used to study microbial systems in both modern and ancient environments.

Teaching

Postdoctoral Advisees


Graduate and Fellowship Programs


  • Biology (School of Humanities and Sciences) (Phd Program)

Publications

Journal Articles


  • Diverse capacity for 2-methylhopanoid production correlates with a specific ecological niche ISME JOURNAL Ricci, J. N., Coleman, M. L., Welander, P. V., Sessions, A. L., Summons, R. E., Spear, J. R., Newman, D. K. 2014; 8 (3): 675-684

    Abstract

    Molecular fossils of 2-methylhopanoids are prominent biomarkers in modern and ancient sediments that have been used as proxies for cyanobacteria and their main metabolism, oxygenic photosynthesis. However, substantial culture and genomic-based evidence now indicates that organisms other than cyanobacteria can make 2-methylhopanoids. Because few data directly address which organisms produce 2-methylhopanoids in the environment, we used metagenomic and clone library methods to determine the environmental diversity of hpnP, the gene encoding the C-2 hopanoid methylase. Here we show that hpnP copies from alphaproteobacteria and as yet uncultured organisms are found in diverse modern environments, including some modern habitats representative of those preserved in the rock record. In contrast, cyanobacterial hpnP genes are rarer and tend to be localized to specific habitats. To move beyond understanding the taxonomic distribution of environmental 2-methylhopanoid producers, we asked whether hpnP presence might track with particular variables. We found hpnP to be significantly correlated with organisms, metabolisms and environments known to support plant-microbe interactions (P-value<10(-6)); in addition, we observed diverse hpnP types in closely packed microbial communities from other environments, including stromatolites, hot springs and hypersaline microbial mats. The common features of these niches indicate that 2-methylhopanoids are enriched in sessile microbial communities inhabiting environments low in oxygen and fixed nitrogen with high osmolarity. Our results support the earlier conclusion that 2-methylhopanoids are not reliable biomarkers for cyanobacteria or any other taxonomic group, and raise the new hypothesis that, instead, they are indicators of a specific environmental niche.

    View details for DOI 10.1038/ismej.2013.191

    View details for Web of Science ID 000331879900016

    View details for PubMedID 24152713

  • Elucidation of the Burkholderia cenocepacia hopanoid biosynthesis pathway uncovers functions for conserved proteins in hopanoid-producing bacteria Environmental Microbiology Schmerk, C. L., Welander, P. V., Hamad, M. A., Bain, K. l., Bernards, M. A., Summons, R. E., Valvano, M. A. 2014

    View details for DOI 10.1111/1462-2920.12509

  • Molecular indicators of microbial diversity in oolitic sands of Highborn Cay, Bahamas Geobiology Edgecomb, V. P., Bernhard, J. M., Beaudoin, D., Pruss, S., Welander, P. V., Shubotz, F., Mehay, S., Gillespie, A. L., Summons, R. E. 2013; 11: 234-251
  • Identification and quantification of polyfunctionalized hopanoids by high temperature gas chromatography-mass spectrometry Organic Geochemistry Sessions, A. L., Zhang, L., Welander, P. V., Doughty, D. M., Summons, R. E., Newman, D. K. 2013; 56: 120-130
  • Identification and characterization of Rhodopseudomonas palustris hopanoid biosynthesis mutants Geobiology Welander, P. V., Doughty, D. M., Wu, C. H., Mehay, S., Summons, R. E., Newman, D. K. 2012; 10: 163-177
  • Discovery, taxonomic distribution, and phenotypic characterization of a gene required for 3-methylhopanoid production Proceedings of the National Academy of Sciences Welander, P. V., Summons, R. E. 2012; 109: 12905-12910
  • Identification of the bacteriochlorophylls, carotenoids, quinones, lipids, and hopanoids of Candidatus Chloracidobacterium thermophilum Journal of Bacteriology Garcia Costas, A. M., Tsukatani, Y., Rijpstra, W. I., Schouten, S., Welander, P. V., Summons, R. E., Bryant, D. A. 2012; 194: 1158-68
  • Using Taguchi-based statistics to produce robust PCR results Bioprocessing Welander, P., Cantin, E., Lundberg, P. 2011; 10: 22-26
  • Identification of a methylase required for 2-methylhopanoid production and implications for the interpretation of sedimentary hopanes Proceedings of the National Academy of Sciences Welander , P. V., Coleman, M. C., Sessions, A. L., Summons, R. E., Newman, D. K. 2010; 107: 8537-8542
  • Hopanoids play a role in membrane integrity and pH homeostasis in Rhodopseudomonas palustris TIE-1 Journal of Bacteriology Welander, P. V., Hunter, R. C., Zhang, L., Sessions, A. L., Summons, R. E., Newman, D. K. 2009; 191: 6145-6156
  • The continuing puzzle of the great oxidation event Current Biology Sessions, A. L., Doughty, D. M., Welander, P. V., Summons, R. E., Newman, D. K. 2009; 19: R567-R574
  • Mutagenesis of the C1 oxidation pathway in Methanosarcina barkeri: new insights into the Mtr/Mer bypass pathway Journal of Bacteriology Welander, P. V., Metcalf, W. W. 2008; 190: 1928-1936
  • Tumor necrosis factor (TNF) protects resistant C57BL/6 mice against herpes simplex virus-induced encephalitis independently of signaling via TNF receptor 1 or 2 Journal of Virology Lundberg, P., Welander, P. V., Edwards, 3rd, C. K., van Rooijen, N., Cantin, E. 2007; 81: 1451-1460
  • Loss of the mtr operon in Methanosarcina blocks growth on methanol, but not methanogenesis, and reveals an unknown methanogenic pathway Proceedings of the National Academy of Sciences Welander, P. V., Metcalf, W. W. 2005; 102: 10664-10669
  • Herpes simplex virus type 1 DNA is immunostimulatory in vitro and in vivo Journal of Virology Lundberg, P., Welander, P., Han, X., Cantin, E. 2003; 77: 11158-11169
  • A locus on mouse chromosome 6 that determines resistance to herpes simplex virus also influences reactivation, while an unlinked locus augments resistance of female mice Journal of Virology Lundberg, P., Welander, P., Openshaw, H., Nalbandian, C., Edwards, C., Moldawer, L., Cantin, E. 2003; 77: 11661-11673

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