Daniel J. G. Lahr (dlahr@cns.umass.edu)
Graduate Program in Organismic and Evolutionary Biology
University of Massachusetts-Amherst
(413) 585-3750
 

Education:

  • Ph.D. Candidate, Program in Organismic and Evolutionary Biology University of Massachusetts, Amherst, MA 2006-present. Dissertation Title: Evolution and Systematics of the lobose testate amoebae (Arcellinida)
  • M.Sc. in Zoology, University of São Paulo, Brazil, 2004-2006. Thesis title: Taxonomy of the Arcellinida in the Tiete River
  • B.Sc. in Biology, University of São Paulo, Brazil, 2001-2003. Scientific Initiation Project: Videos as a tool for Protistology teaching.

Research Interests:

I’m interested in gene and genome evolution, morphology, taxonomy and ecology of the lobose testate amoebae (Arcellinida). The Arcellinida are a group of lobose amoebae characterized by having a shell (or test). They are very common in freshwater and soil habitats, and play an important role in nutrient cycling and ecology. However, research in these interesting organisms has been restricted and much remains to be done.
 

This is a Trygonopyxis on top of my index finger. The inset shows the exact same individual in higher magnification, the shell is about 150 mm in diameter.

  

My PhD research has two main foci:

1. Evolution of protein coding genes in the genus Arcella, with emphasis on the actin gene family. We are exploring the genomic processes behind a wide variety of haplotypes found in both the population and individual level. We are on the process of preparing the first manuscript that deals with actin evolution in Arcella, and we are also expanding this work to other closely related species and genera, looking simultaneously at genome evolution, and testing hypothesis of inheritance in natural populations.
 
A group of Arcella vulgaris performing the mysterious plasmogamy, where multiple individuals come together and fuse their cytoplasm. This could be a form of foraging, a method of exchanging cytoplasmic bacteria, or a form of sexual reproduction.  
 
2. Evolution of protein coding genes in the genus Arcella, with emphasis on the actin gene family. We are exploring the genomic processes behind a wide variety of haplotypes found in both the population and individual level. We are on the process of preparing the first manuscript that deals with actin evolution in Arcella, and we are also expanding this work to other closely related species and genera, looking simultaneously at genome evolution, and testing hypothesis of inheritance in natural populations.
 

A Netzelia wailesi inside the microcentrifuge tube, ready to be PCR’d.

  
 

From my Ph.D. work, we have so far published two pieces of research: a review on the variability of genome dynamics across eukaryotes and an experimental analysis that sheds more light into the excruciating issue of PCR induced recombination, a methodological problem that plagues any research that is PCR-based.

Laura W. Parfrey, Daniel J. G. LAHR, Laura A. Katz. 2008. The dynamic nature of eukaryotic genomes. Molecular Biology and Evolution. 25(4):787-794. ( http://mbe.oxfordjournals.org/cgi/content/short/25/4/787)

Daniel J. G. LAHR, Laura A. Katz. 2009. Reducing the impact of PCR-mediated recombination in molecular evolution and environmental studies using a new-generation high-fidelity DNA polymerase. Biotechniques. 47(4). http://www.biotechniques.com/BiotechniquesJournal/2009/October/Reducing-the-impact-of-PCR-mediated-recombination-in-molecular-evolution-and-environmental-studies-using-a-new-generation-high-fidelity-DNA-polymerase/biotechniques-176950.html)
 
My Masters work is on morphology and taxonomy of several genera of testate amoebae (Arcella, Difflugia, Lesquereusia and Centropyxis) where I have tried to expose some fundamental differences and difficulties when establishing taxonomic identity in microbial eukaryotes, especially related to comparisons between traditional description techniques and modern microscopy and molecular work. These are the papers published so far:

Daniel J. G. LAHR and Sônia G. B. C. Lopes. 2006. Morphology, biometry, ecology and biogeography of five species of  Difflugia Leclerc, 1815 (Arcellinida: Difflugiidae), from Tiete River, Brazil Acta Protozoologica 45(1):77-90 ( http://www.nencki.gov.pl/pdf/ap/ap879.pdf)

Daniel J. G. LAHR and Sônia G. B. C Lopes. 2007. Ultra-structure and Biometry of Three Lobose Testate Amoebae of the Family Lesquereusiidae (Tubulinea: Arcellinida) Based on Specimens from Sao Paulo, Brazil. Acta Protozoologica 46(4):339-348 ( http://www.eko.uj.edu.pl/ap/index.php?option=com_docman&task=doc_download&gid=59&Itemid=27)*

Daniel J. G. LAHR, Philip J. Bergmann, Sonia G. B. C. Lopes. 2008. The Taxonomic Identity in Microbial Eukaryotes: a Practical Approach Using the Testate Amoeba Centropyxis to Resolve Conflicts Between Old and New Taxonomic Descriptions. Journal of Eukaryotic Microbiology 55(5):409-416 (http://www3.interscience.wiley.com/cgi-bin/fulltext/120119076/HTMLSTART)

Daniel J. G. LAHR and Sônia G. B. C. Lopes. 2009. Evaluating the Taxonomic Identity in Four Species of the Lobose Testate Amoebae Genus Arcella Ehrenberg, 1832. Acta Protozoologica. 48(2):127-142 (http://www.eko.uj.edu.pl/ap/index.php?option=com_docman&task=doc_download&gid=119&Itemid=27)*

* Please note that on Acta Protozoologica’s new website you need to create an account (free!) before downloading these papers. If you can’t download them for some reason, feel free to contact me (link to my e-mail: dlahr@cns.umass.edu)

 

Previous work on educational movies

I became interested in microbiology after seeing Prof. Grell’s (http://www.iwf.de/iwf/do/mkat/listing.aspx?Action=Schnell&SearchStr=GRell) and Prof. Netzel’s (http://www.iwf.de/iwf/do/mkat/listing.aspx?Action=Schnell&SearchStr=netzel) beautiful movies about several microbial eukaryotes, many of them on testate amoebae. Initially, I thought using movies would be a great way to introduce young students to the wonderful world of microbial eukaryotes. Additionally, not all schools have the necessary funds to afford a good microscope and trained microscopists, but every school has some system to show movies.

We have produced three movies from this initiative. These are freely distributed and intended for use in college classrooms. Please note that they are in Portuguese (but the images should speak any language!).

Mac users: These links are intended for PC users, and may or may not work on different Mac configurations. One option is to download the full video, and extract it using the free version of Stuffit Expander (link: http://my.smithmicro.com/mac/stuffit/index.html). This will extract- an avi file that should play on Quicktime. Alternatively, you can watch the YouTube versions (lower resolution).

The life of amoebae - A vida das amebas
Length 10min. Authors: Daniel J. G. LAHR; Enio Mattos; Sônia Lopes

Registered in the Brazilian National Library, number 373.297. All rights reserved. Copy and free-distribution are allowed, as long as the authors and sources are cited.

Download (http://www.ib.usp.br/md/arquivos/amebas.exe)
Windows Media Player for slow connections (mms://wms.emm.usp.br/ib/bio_ameba.wmv%20)
Real Media High Quality (http://real.emm.usp.br:8080/ramgen/ib/bio_amebas_t1.rm)
Real Media (http://real.emm.usp.br:8080/ramgen/ib/bio_amebas_lan.rm)
MPEG4 High Qualilty (rtsp://mp4.emm.usp.br:554/ib/bio_amebas_t1.mp4)
MPEG4 (rtsp://mp4.emm.usp.br:554/ib/bio_amebas_lan.mp4)

The life of ciliates – A vida dos ciliados
Length: 11min. Authors: Mariana Campos; Daniel J. G. LAHR; Enio Mattos; Sônia Lopes

Registered in the Brazilian National Library, number 373.293. All rights reserved. Copy and free-distribution are allowed, as long as the authors and sources are cited.

 

Download (http://www.ib.usp.br/md/arquivos/ciliados.exe)
Windows Media Player for slow connections (mms://wms.emm.usp.br/ib/bio_ciliados.wmv%20)
Real Media High Quality (http://real.emm.usp.br:8080/ramgen/ib/bio_ciliados_t1.rm)
Real Media (http://real.emm.usp.br:8080/ramgen/ib/bio_ciliados_lan.rm)
MPEG4 High Quality (rtsp://mp4.emm.usp.br:554/ib/bio_ciliados_t1.mp4)
MPEG4 (rtsp://mp4.emm.usp.br:554/ib/bio_ciliados_lan.mp4)

Sampling and maintaining freshwater protists – Coleta e manutenção de protistas de água-doce
Length: 5min. Authors: Daniel J. G. LAHR; Mariana Campos; Enio Mattos; Sônia Lopes

Registered in the Brazilian National Library, number 373.259. All rights reserved. Copy and free-distribution are allowed, as long as the authors and sources are cited.

Download (http://www.ib.usp.br/md/arquivos/coleta.exe)
Windows Media Player for slow connections (mms://wms.emm.usp.br/ib/bio_coleta.wmv%20)
Real Media High Quality (http://real.emm.usp.br:8080/ramgen/ib/bio_coleta_t1.rm)
Real Media (http://real.emm.usp.br:8080/ramgen/ib/bio_coleta_lan.rm)
MPEG4 High Quality (rtsp://mp4.emm.usp.br:554/ib/bio_coleta_t1.mp4)
MPEG4 (rtsp://mp4.emm.usp.br:554/ib/bio_coleta_lan.mp4)