Transmission Measurement of Volvox Algae Using a MSV-5000 Series Microscopic Spectrophotometer

Download PDF October 3, 2017

Introduction

MSV-5200
UV-Visible/NIR Microscopic
Spectrophotometer

The MSV-5000 Series microscopic spectrophotometer is for transmission and reflection measurements in a wide wavelength range from the ultraviolet to near infrared. The built-in high resolution camera enables sample areas as small as 10 mm in diameter to be precisely measured and is therefore gaining popularity in the bioscience field for analyzing localized constituents in living cells.

Volvox is a form of algae which forms localized, spherical colonies of up to 50,000 cells in the mother colony. In this application note, a daughter colony of Volvox was measured to obtain the absorption spectra and fixed-wavelength mapping.

Fig. 1. Dried volvox.

Volvox, has a localized cellular density due to its internal daughter colonies and was measured to obtain absorption spectra and fixed wavelength mapping data.

Experimental

Measurement Conditions
AbsorptionFixed Wavelength Mapping
UV-Vis Bandwidth5 nmMode/WavelengthLattice/672 nm
Scan Speed1000 nm/minBandwidth2 nm
ResponseQuickResponseFast
Data Interval1 nmData Interval30 μm
Cassegrain Objective16xCassegrain Objective16x
Aperture50 mmΦAperture30 μmΦ

Keywords

UV-0024, MSV-5100 UV-Vis microscopic spectrophotometer, MAXY-501 Automatic XYZ stage, Biochemistry

Results

Figure 2. Absorption spectrum of Volvox (right) and chlorophyll a and b (right)1.

The measured absorption spectrum of Volvox is shown in Figure 2 on the left. On the right the absorption spectra of chlorophyll a and b are shown, which are major components of algae1 and therefore Volvox. The published literature data is measured under acetone solvent conditions and depending on the solvent conditions, the peak positions of chlorophylls can be shifted 2-7 nm. However, when comparing the obtained Volvox spectrum to the literature chlorophyll spectra it can be assumed that Vovlox contains both chlorophyll a and b.

Figure 3. Observation image (left) and color-coded diagram of mapping measurement (right) of mapping.

Fixed wavelength mapping measurements were obtained at 672 nm, the peak observed in the absorption spectrum in Figure 2. The high speed mapping images are shown below in Figure 3. The areas with higher cellular density are easily visualized in both the sample observation image and color-coded diagram.

References

1. Tanaka, Ryouichi and Ayumi Tanaka. “Chlorophyll cycle regulates the construction and destruction of the light-harvesting complexes.” Biochimica et Biophysica Acta (BBA)-Bioenergetics, 1807, 9, 2011, 968-976.

About the Author

Leah Pandiscia received her PhD from Drexel University where she studied Biophysical Chemistry. She is a Spectroscopy Applications Scientist at JASCO.