Paramecium food vacuols 2
This is a paramecium with food vacuoles stained by Congo Red stained yeast cells. In comparison to the previous image in my photo stream, this was after about 7:20 hours vs. 0:5 hour from feeding the stained yeast to the culture. Note how some of the food vacuoles are now blue. Congo Red is a pH indicator, being red at high pH and blue at low pH. The transition from red to blue is around pH 3-5.2. Thus, the digestion process appears to produce acidic conditions in the food vacuole.
This micrograph shows the two contractile vacuoles in opposite states, with the one at the left expanded and the one at the right contracted. The radiating canals are plainly evident around both.
A specimen of Northern Indiana Lake water was cultured to increase ciliate concentration. The ciliates were stained using Congo Red stained yeast. The 0.25 g. yeast was added to 20 ml water and then boiled to kill the yeast. A small amount of Congo Red dye was added to the cooled liquid to obtain a dark red colour. The stained yeast was added to an aliquot of the culture and placed on 3 microscope slides over a period of several hours. The Congo Red is an acid dye. Acid dyes have been shown not to stain cytoplasm in paramecium. The paramecia and other ciliates eat the stained yeast such that the food vacuous become evident. Over time as digestion occurs, some of the Congo Red turns blue as the acidity increases. However, paramecia were observed excreting red stained yeast, so this color change does not always occur.
This protocol is based largely on www.gtac.edu.au/wp-content/uploads/2016/01/EnergisingCell.... Most protocols had the Congo Red added to the live yeast prior to boiling. As a carcinogen, I did not want to deal with the vapours. I thought it might stain the dead cells and then I found the Georga Tech protocol which confirmed this.
Imaged on an Olympus BHS microscope using a Sony A7S.
Paramecium food vacuols 2
This is a paramecium with food vacuoles stained by Congo Red stained yeast cells. In comparison to the previous image in my photo stream, this was after about 7:20 hours vs. 0:5 hour from feeding the stained yeast to the culture. Note how some of the food vacuoles are now blue. Congo Red is a pH indicator, being red at high pH and blue at low pH. The transition from red to blue is around pH 3-5.2. Thus, the digestion process appears to produce acidic conditions in the food vacuole.
This micrograph shows the two contractile vacuoles in opposite states, with the one at the left expanded and the one at the right contracted. The radiating canals are plainly evident around both.
A specimen of Northern Indiana Lake water was cultured to increase ciliate concentration. The ciliates were stained using Congo Red stained yeast. The 0.25 g. yeast was added to 20 ml water and then boiled to kill the yeast. A small amount of Congo Red dye was added to the cooled liquid to obtain a dark red colour. The stained yeast was added to an aliquot of the culture and placed on 3 microscope slides over a period of several hours. The Congo Red is an acid dye. Acid dyes have been shown not to stain cytoplasm in paramecium. The paramecia and other ciliates eat the stained yeast such that the food vacuous become evident. Over time as digestion occurs, some of the Congo Red turns blue as the acidity increases. However, paramecia were observed excreting red stained yeast, so this color change does not always occur.
This protocol is based largely on www.gtac.edu.au/wp-content/uploads/2016/01/EnergisingCell.... Most protocols had the Congo Red added to the live yeast prior to boiling. As a carcinogen, I did not want to deal with the vapours. I thought it might stain the dead cells and then I found the Georga Tech protocol which confirmed this.
Imaged on an Olympus BHS microscope using a Sony A7S.