Ciliate conjugation is a sexual phenomenon that results in genetic recombination and nuclear reorganization within the cell. In most ciliate groups, however, the cells separate after conjugation, and both form new macronuclei from their micronuclei.
Before the bun, hamburgers are said to have been served between two pieces of bread. In fact, a ground beef patty was known as Hamburger steak (first mentioned in an American cookbook in 1891); when this was put between bread or in a bun it was called a Hamburger sandwich.
When you look into the history of hamburgers in the U.S., you'll find sources proclaiming the inventor to be (from left) Louis Lassen, Hamburger Charlie Nagreen, or the Menches Brothers. The history of the hamburger is truly a story that has been run through the meat grinder.