Definition of courier: An individual responsible for the exchange of items between two or more parties. Couriers are usually employed by a company that charges a flat rate to the party using the courier service. Federal Express, UPS, DHL, and the United States Post Office all employ couriers to deliver mail and packages.
At least 3 bacterial morphotypes, as well as fungal mycelia, thelastomatid nematodes, and ingested material are found in the hindgut. At annual molt, the lumen bacteria virtually disappear; presumably they are replaced from anterior gut regions, ingested exuvium, and ingested soil.
Furthermore, some bacteria have linear chromosomes. Borrelia 3 have linear chromosomes and most strains contain both linear and circular plasmids; most of the bacteria in the genus Streptomyces 4 have linear chromosomes and plasmids and some have circular plasmids as well. For example, linear DNA was precipitated in the most commonly used procedures for purifying bacterial plasmids, and the procedures for purifying chromosomal DNA relied upon the differential binding of ethidium bromide to sheared DNA fragments compared to circular DNA.