VOLUM OMAGIAL - Facultatea de Ştiinţe ale Naturii şi Ştiinţe Agricole

Simona Ghiţă et al. / Ovidius University Annals, Biology-Ecology Series 14: 127-137 (2010)
very low (and responsible for the low increase in the
average cell lengths in M3). In M3 (control) one can
see a rather constant length of some cells during
incubation (2,15±0,37) whereas in M2 there was a
sudden increase in cell length (6,46±1,54) to the time
T2 (4 hours incubation) then there was a steady
increase until T4 (8 hours incubation).
In Figure 7 are some random fields of cells in
the two microcosms to highlight how cell elongation
occurred from the T o to T4 only in M2.
a b
c d
Fig 7. Evaluating cell elongation in microcosm 2 (a-
To and b-T4) respectively in the control microcosm
(c- To and d-T4)
Digital Image Analysis and automated image
analysis for epifluorescence
The automated approach will not only remove
the need for tedious manual analysis work, but also
enable biologists to measure cellular features not
feasible by the standard manual techniques
(Selinummi, 2008).
In our studies we used ImageJ software - a
public domain Java image processing and analysis
program inspired by NIH Image for the Macintosh,
who runs, either as an online applet or as a
downloadable application, on any computer with a
Java 1.5 or later virtual machine. This software was
used to display, edit, analyze, process, save and print
8–bit, 16–bit and 32–bit epifluorescence digital
images, many image formats including TIFF, GIF,
JPEG, BMP, supporting ‘stacks’and hyperstacks, a
series of images that share a single window.
131
For study bacteria and cyanobacteria from our
samples ImageJ was the main software for measure
the length of cells and pixel value statistics of userdefined
selections, creating density histograms and
line profile plots, supports standard image processing
functions such as contrast manipulation, sharpening,
smoothing, edge detection and median filtering.
Digital images are two-dimensional grids of
pixel intensities values with the width and height of
the image being defined by the number of pixels in x
(rows) and y (columns) direction. Thus, pixels
(picture elements) are the smallest single components
of images, holding numeric values – pixel intensities
– that range between black and white (ImageJ user
guide). Microphotographs used in this study was
RGB images, RGB/HSB stacks, and composite
images.
People can see color with significant variations
and the popular phrase “One picture is worth ten
thousand words” may not apply to certain color
images, especially those that do not follow the basic
principles of Color Universal Design. That why this
combining digital image analysis and automated
analysis methods was usefull to distinguish some
morphological and functional aspects of prokaryotes.
We displied with ImageJ simultaneously several
selections or regions of interest named ROIs, who can
be measured, drawn or filled. Selections was initially
outlined in one of the nine ImageJ default colors
(Red, Green, Blue, Magenta, Cyan, Yellow, Orange,
Black and White) and then, once created, selections
was contoured or painted with any other color. Most
of ImageJ analyses was printed to the Results table.
Fig 8. The ImageJ Window
(http://rsbweb.nih.gov/ij/).
Straight Line Selection with “Alt” from
computer keeps the line length fixed while moving
either end of the line and forces the two points that
define the line to have integer coordinate values when
creating a line on a zoomed image.
The CellC software is the second software used
in automated analysis of our microscopy images like
cell enumeration and measurements of cell’s
properties (size, shape, intensity). We applied the