Lew Research Home

sunrise bicycle

Roger R. Lew

Professor of Biology
York University
Department of Biology
4700 Keele Street
Toronto, Ontario
phone: (416) 736-5243
fax: (416) 736-5698

Lew Laboratory Members

Roger R. Lew (Principal Investigator)

Past Lab Members

Miranda Lorenti (Biophysics Research Assistant)

pH effect on algal growth

Oxygen Electrode Setup (summer, 2013) Miranda developed methods and experiments to study photosynthesis in Eremosphaera viridis, systematically characterizing fundamental properties (carbon dioxide dependence, pH dependence of both photosynthesis and growth, and intracellular architecture).

Here is her photosynthetica report [pdf].

Fluorescence imaging of Eremosphaera And more recently, imaged systrophe using FM4-64 to explore cytoplasm re-arrangements (green fluorescence) during chloroplast (red fluorescence) translocation.

(September, 2014 through June, 2015) Miranda is sequencing plc--1 mutants of Neurospora crassa [RIP sequence figure --pdf].

Dmitry Neymark (Biophysics Research Assistant) growth vector response to electrical field

apparatus for creating voltage field (summer 2014 through April 2015) Dmitry Neymark designed an apparatus for creating electric fields to examine the growth responses of the fungus Neurospora crassa. He collected data and developed data visualization techniques of the electrical field-directed growth. Here is his first auctus electrica report [pdf]. He subsequently increased the distance between the electrodes and demonstrated cathodotropism. Unfortunately, he didn't realize that large pH changes also occur when the electric field is generated until the end of his project, as described in his second auctus electrica report [pdf]. So, it remains to be seen if hyphal growth is guided by pH or an electric field.

Omar Abid (Biophysics Research Assistant)

circuit diagram for voltage clamp (fall, 2013 - spring, 2014) Omar Abid designed and fabricated a new and improved voltage clamp circuit for current-voltage measurements of hyphal cells. Here is his instrumentation design report [pdf].

Rachel Giblon (Biophysics Research Assistant)

(2013-2014) Rachel collected electrophysiological and imaging data on phospholipase C mutants in support of ongoing research on signalling control of morphogenesis.

Movie of fungal growth through a magnetic field(summer, 2013) Rachel decided to get physical and documented the effect of a 1 Tesla magnetic field (about 10,000 times the earth's magnetic field) on the growth of Neurospora crassa. There was no effect. Click on the picture for a movie (4.6 MB). Here is her magneto report [pdf].

Current-voltage time dependence(fall, 2012 through spring, 2013) Rachel used dual impalements to measure the cable properties of Neurospora crassa hyphae. Click on the picture for a bigger version of her measurements of time-dependent clamping currents in hyphae.

She went on to compare the electrical properties of wildtype and a strain expressing high levels of a GFP-tagged histone (the research question was whether overexpressing histones in the nuclei affects the electrophysiology of the fungus). Here is the report of her GFP expression research [pdf]. And finally, Rachel voltage clamped and imaged plc--1 mutants (fall, 2013 through spring, 2014).

Aryan Abadeh (Biophysics Research Assistant)

Hyphal architecture (2011-2012) Aryan explored the nature of mass flow in Neurospora crassa hyphae: Using dual-flurochrome labeling and trans-hyphal osmotic gradients.

Here are some examples:

And his advective flow report [pdf]. His research on mass flow was published in Microbiology [link].

Kevin Cross (Biophysics Research Assistant)

oil droplet flow in Chara cells(summer, 2013) Kevin used his micro-manipulation skills to inject silicon oil into Chara cells to directly assess the hydrodynamic nature of cytoplasm streaming.

(fall, 2012 through spring, 2013) Kevin impaled Eremosphaera viridis cells to measure their turgor and determine the effect of high light intensity.

(summer, 2012) Kevin used the BLM technique to characterize ion channels from Eremosphaera viridis membranes.ion channels

Nicolas Epelbaum (Biophysics Research Assistant)

(2012) Nicolas explored the photosynthetic activity of Eremosphaera viridis and its dependence on light.

Here are data showing oxygen evolution and systrophe after bicarbonate addition at various light intensities [png]. Here is his report [pdf].

Karen Ng (Biophysics Research Assistant)

(2011) Karen unravelled the organellar dynamics in Eremosphaera viridis using fluorescent reporter dyes and chlorophyll autofluorescence.

Here are examples of mitochondrial movements in Eremosphaera viridis:

Here is her report [pdf]. (2012) Karen continued to work with Eremosphaera viridis, measuring its turgor.

Ahmed Hamam (MSc)

Kevonne Kerr (Biochemistry Honours research)

BLM workstation (2011) Kevonne researched the effects of insulin (as a serosal protein mimick) on membranes made up of phosphatidylethanolamine-succinyl and phosphatidylethanolamine-polyethyleneglycol (a model for vesicle-mediated drug delivery) using bilayer lipid membranes (click on photo to see the BLM chamber apparatus).

Here is some data: [controls] and [insulin].

Tung Bui (Biophysics Research Assistant)

(2010-2011) Tung assisted Ahmed Hamam in the characterization of calcium transport knockout mutants of Neurospora crassa as a RAY (Research at York) Research Assistant.

Raanan Marants (Biophysics Research Assistant)

(2011) Raanan performed three-dimensional reconstructions of mitchondrial and chloroplast spatial locations in Eremosphaera viridis as a RAY Research Assistant. His viridis fluorescence report [pdf].

Here are three examples of his first reconstructions: At the cell surface [mov] [mp4]; A close-up [mov] [mp4]; In a dividing cell [mov] [mp4].

Sandra Khine (Biophysics Research Assistant)

(2010) Sandra explored the pH dependence of growth and the electrical properties of the unicellular alga Eremosphaera viridis. Here is her report [pdf].

(2009) Sandra used cable theory to calculate current densities in trunk hyphae of Neurospora crassa as a RAY (Research at York [link]) Research Assistant.

Robert Moscaritolo and Dana Gasumova (Biophysics Research Assistants)

(2009) Robert and Dana characterized systrophe (chloroplast movements) in response to high intensity light using the acidophile green alga Eremosphaera viridis as RAY (Research at York [link]) Research Assistants. Here is their systrophe report [pdf]

Time lapse movies:
  • Systrophe: Incipient to Full (pseudo-colored) [1.5 MB .mov format] [0.6 MB .mp4 format].
  • Recovery: Transition to Low-level Light (pseudo-colored) [1.6 MB .mov format] [0.5 MB .mp4 format].
  • Chloroplast Imaging: 467 4 nm high intensity irradiation, 590 nm long-pass imaging of chlorophyll fluorescence [11.3 MB .mov format] [6.3 MB .mp4 format].
  • Light Intensity Dependence:
  • 450 umol photons per square meter per second [4.4 MB .mov format] [2.0 MB .mp4 format].
  • 1000 umol photons per square meter per second [3.3 MB .mov format] [1.5 MB .mp4 format].
  • 1842 umol photons per square meter per second [3.0 MB .mov format] [2.3 MB .mp4 format]. Cool
  • 2761 umol photons per square meter per second [5.7 MB .mov format] [2.4 MB .mp4 format].
  • Here is a time lapse of cell division [805 kB .mov format] [214 kB .mp4 format].

    Scott McClure (Biophysics Research Assistant)

    (2009) Scott continued the phenotypic characterization of an aquaporin knockout in Neurospora crassa as an NSERC Summer Research Assistant. Report [pdf]

    Vitaliy Kapishon (Research Assistant)

    (2008) Besides doing genetic crosses and producing double mutants of Neurospora crassa, Vitaliy also characterized the biophysical properties of dipalmitoylphosphatidylethanolamine succinyl bilayers, as a RAY (Research at York [link]) Research Assistant. Report [pdf]

    Ming-Sheng Lim (Research Assistant)

    (2008) Ming undertook a phenotypic characterization of an aquaporin knockout in Neurospora crassa as an NSERC Research Assistant. Report [pdf]

    Maryam Rasti-Talkhoncheh (Research Assistant)

    (2008) Maryam screened a diversity of Neurospora crassa knockout mutants for osmotic sensitivity as a RAY (Research at York [link]) Research Assistant. Report [pdf]

    Shanar Nasserifar (Research Assistant)

    (2007) Shanar screened semi-colonial mutants of Neurospora crassa for the presence or absence of electrical changes in response to hyperosmotic treatment as a RAY Summer Research Assistant. Report [pdf]

    Dr. Mary A. Bisson (Visiting Sabbaticant)

    Mary visited in the fall (2005) to research blue light regulation of ion transport in Arabidopsis thaliana.

    Zohaib Abbas (Research Assistant)

    (2006) Zohaib characterized a Neurospora crassa ser/thr kinase mutant (cot-1) to determine if ion transport plays a role in the heat-induced hyperbranching phenotype of the mutant. Report [pdf]