~~~ "Jurassic Park" Bacterium! ~~~

Well, not quite......... but!!

Raúl Cano and Monica K. Borucki, California Polytechnic State University at San Louis Obispo, California, recently published an article in the journal Science [Science Vol. 268; page 1060-1064; 19 May, 1995, entitled: "Revival and Identification of Bacterial Spores in 25- to 40-Million-Year-Old Dominican Amber"] which describes the isolation and identification of a viable bacterium from the gut of a bee trapped in amber (fossilized pine-tree resin) found in the Dominican Republic. Please see:
Ancient Bacteria; Cano at Cal Poly - San Luis Obispo, CA.

It is known that many present-day species of bee maintain a symbiotic (help one another) relationship with various species of bacteria of the genus Bacillus within their gut (normal gut flora for some bees, just as E. coli bacteria are normal members of our gut flora). It is also known that Bacillus is one genus of bacteria which can form spores - a kind-of "suspended animation" special life-form of the microorganism - which allows survival for many, many years. In fact, the conditions (temperature and time) required for sterilization of surgical instruments, etc., inside an autoclave (pressure-cooker) have been determined by finding under what conditions spores are killed (please see Better use a pressure cooker!. If spores are killed, then everything else is also killed). To date, the best-tested, most well-documented, longest spore survivor is about 70 years (from a sealed tube prepared by the great scientist, Louis Pasteur, which was opened in 1956). Further, at least 25-million-year-old Bacillus DNA had already been identified within the gut of a bee trapped in amber. Therefore, these scientists reasoned that the bee might have Bacillus spores inside its "stomach," which might be recoverable, and which might regenerate into what are called vegetative (living, dividing) cells, if the spores were placed into nutritious, healthy growth conditions. Consequently, these investigators began the search for these ancient bacteria.

All of the manipulations to obtain the bacterium from the bee trapped inside the amber were performed under sterile conditions. To begin with, while working inside (arms and hands) a special box (called a laminar-flow hood... all of the air passes through a special filter, and always blows toward the person using the hood) these investigators chemically-sterilized all of the amber surfaces, then cracked the amber with sterilized tools to expose the bee (Proplebia dominicana, "....an extinct species of neotropical bee found in 25- to 40-million-year-old amber from the Dominican Republic"). The gut contents of the bee were removed, and added to a nutrient-containing liquid called trypticase soy broth. This broth is very nutritious, (bacteria love it) and even weak organisms can be coaxed to recover when placed within. After incubating the broth for a period of time, living, growing bacteria were identified within the culture! Now, the effort turned to testing all of the equipment, solutions, and anything else present within the laminar-flow hood during the preparation of the culture, for possible contamination by present-day bacteria. Nothing was found. Therefore, these scientists concluded that the origin of the bacteria growing within the broth culture was the gut of the ancient bee. Next came the effort to identify the kind of bacterium which had been isolated.

The methodology involved use of small pieces of DNA called primers, whose nucleotide sequences were known to coincide with certain regions of present-day Bacillus ribosomal RNA (rRNA) genes [please see: What the Heck is a Gene?]. Ribosomal RNA within a cell is unique to every species of life, and can therefore be used to identify an organism, and even the species of organism. When added to test DNA, these primers will associate with the test DNA through base-pairing, if the DNA sequence between the primer and one strand of the test DNA are complimentary. This association allows the technique called PCR [please see: What the Heck is PCR?] to be used, which results in the amplification (huge increase in the number of copies) of the gene with which the primer has associated. Thus, PCR allows generation of enough DNA from an incredibly small amount of original test DNA to be tested in all sorts of ways. By using this technique, the 25- to 40-million-year-old rRNA gene (in the now-living organism!) was identified as Bacillus DNA, and most closely resembled that of B. sphaericus! Biochemical studies on the isolate, along with morphological characteristics, also place the organism within the B. sphaericus grouping.

Of course, this information has caused quite a stir in the scientific community, and there are efforts underway by other investigators to independently attempt a similar isolation of the organism (or any organism for that matter) from other bees trapped in amber those many years ago. Only through this type of validation will there be agreement among scientists that these investigators have indeed sucessfully isolated a living remnant of our ancient past.

Book: Don't Touch That Doorknob!

Copyright John C. Brown, 1995
Acknowledgement and with permission of Cal Poly: The above in-line image of an extinct bee trapped in amber, is a re-sized Cal Poly Image.
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