is being refined and the complexities of Borrelia genetic gymnastics challenges many
long held textbook based beliefs about the repertoire of Borrelia proteins.
There are problem areas in the arena of Serology "assisted" diagnosis of Lyme borreliosis.
An appreciation of the intrinsic Borrelia Genome in Flux concepts facilitates an improved
respect for the vast numbers of structural variation in Borrelia protein epitopes.
Genome in flux and its consequent Proteins in flux offers a pathway to the appreciation
of the intrinsic shortcomings of Serology methods based on reagents prepared from the
original B31 strain of Borrelia burgdorferi.
I offer some images for your consideration:
The textbook cartoon of the chromosome and the Plasmids of Borrelia burgdorferi....
[ from Stewart, p., et al, 2005, Plasmid 53:1-13 and reproduced from Chaconas,G., Molecular Microbiology,2005,58(3): 625-35.
Segmentation of DNA and RNA containing regions within a Borrelia burgdorferi Spirochete strain B31
Acridine orange stain with Calcium Chloride differentiation - 1000x oil immersion magnifiction
DNA regions in yellow and green,RNA regions in Orange/red [scroll the image to see all ]
Physical segmentation of Borrelia burgdorferi (B31) stained with Oligreen , Epifluorescence, magnification 1000x, oil immersion microscopy (scroll the image to see the segmented spirochete at the bottom)
"COPY NUMBER" issues ---1. How many copies of the chromosome of Bb reside within each spirochetal cell?
___2. How many copies of each of the Plasmids reside within each spirochetal cell?
The answser to question 1. from my reading of the current literature is that
Correction: In the Monograph Borrelia Molecular Biology Host Interactiuns and Pathogenesis Radolf,j, and Samuels D.Scott ...Dr George Chaconas speaks of ONE chromsome per B. burgdorferi bacterium (page 55)16 copies of the chromosome
reside within each Borrelia burgdorferi cell. ( This is in line with 16 chromosomal copies present
within each cell of Borrelia hermsii)
Second Correction and Update on The number of Chromosomes per Borrelia Cell:
Dr. Joseph Hinneusch and Dr. Alan Barbour have a Correction on the "Copy Number" of
Chromosomes per individual borrelia cell as follows;
TEN Chromosome copies per cell for Short borrelia forms ( Usually seen in Primary cultures)
Thirty Chromosome copies per cell for Long borrelia forms ( usually seen in long term cultures)
References for this revision : Dr Hinnenusch's article on Nulceoids of Borrelia published in 1997
Journal of Bacteriology.
The answer to question number 2...from my readiing of the current literature is that there is ONE copy of EACH plasmid per copy of the chromosome of Borrelia burgdorferi. Corrrection: In the Radolf and Samuels monograph Page 55, Dr S. Casjens speaks of copy numbers of 1 -2 per Chromosome.
Second Correction: See above Statement
Note the Ratio of Chromosomes to Plasmids approximately 1::21 remains the same
Minimal INFECTIVE unit for Borrelia burgdorferi in various hosts.????
There is no data in the literature to answer this question,
Perhaps a borrelia burgdorferi spirochete single genome - chrosome and corresponding complement
of ( 21 times ??) plasmids might enable a single Borrelia burgdorfei spirochete to transmit infection
from vector to host ( or for that matter from infected mouse to feeding nymphal tick ) This is merely speculation on my part.
Please recall that when a single borrelia burgdorferi spirochetes undergoes Segmentation - as in the image
above, ... each segment could potentially contain all of the genetic material ( chromosome and full plasmid complement) as is illustrated in the Genomic cartoon, which is the first image from Dr P. Stewart's paper
Alan B. MacDonald, MD