The first of the year in the Christina Difonzo Seminar Series in Biology took place on Jan. 24. The Mercyhurst community welcomed Mike Ganger, Ph. D. from Gannon University.
Ganger discussed his current student-driven research project titled, “Bacteria affect sex determination and rhizoid development in the homosporous fern Ceratopteris richardii.”
Ganger’s seminar began with a rudimentary discussion of the life cycle of ferns or how he affectionately deemed it “the awful no good horrible life cycle.”
He glossed over several topics in an effort to ensure everyone in the room could comprehend the more complex information he would cover. The research is centered around the fern Ceratopteris richardii.
In order to understand this fern, it is noted that the hermaphrodite can be known as the “female” and produces a hormone known as antheridiogen that will create the sperm producing “male” antheridium.
To clarify, if spores are hit by antheridiogen by a hermaphrodite, it will become male, and if not it will remain a hermaphrodite.
One of the hypotheses tested was based on the Darwinian ideology of sexual selection.
Females have a higher demand for resources than males do, so when there are not a lot of nutrients available more males will come to be.
The experiment began with 100% nutrient agar that was cereal diluted across 500 sterile petri dishes in order to compare high and low nutrients on a plot.
The results showed that low nutrients do not produce low amounts of hermaphrodites like Darwin would suggest, but instead it is just the antheridiogen.
This led to the new bacteria hypothesis. In plants, bacteria located in and around the roots communicate with each other via signaling and essentially tell plants what to do or how to grow.
Bacteria added to the system produced a 5 to 7% increase in hermaphrodites by messing with the antheridiogen system.
The bacteria also increased the length of the rhizoids and decreased the overall number of rhizoids.
Some possibilities of sex determination are that the bacteria eat antheridiogen, bacteria increase nutrients in petri dishes, and the plant perception of good bacteria leads to a detection of lipopolysacharides, flagellin, N-acetylglucosamine.
These possibilities were tested by treating 20 plates, 10 with bacteria and 10 without an extracting fluid. After a series of biological techniques were used, they were tested on the ferns after two weeks.
The results showed that the bacteria does not eat antheridiogen, bacteria does not alter nutrients, and bacteria does make it through the autoclave.
All bacteria that are gram negatives seem to increase the length of the rhizoids. It is also noted that through a mistake in the controls it was discovered that fungi too affected rhizoid length.
This research is far from being conclusive of the role of bacteria in determining the sex of Ceratopteris richardii, but has raised more than a few interesting questions along the way.
“It was a very interesting presentation in a field of biology I am not very familiar with and showed me some different opportunities I could pursue with my biology degree after I graduate,” junior Biology major and aspiring future optometrist Bryce Niebauer said.
Dates of future seminars are posted on the Mercyhurst Hub and on posters all over campus. These seminars are freely available for all students.