Biology Reference
In-Depth Information
used as a model organism in population biology because its life history parameters related to
population dynamics can conveniently be measured and manipulated under controlled laboratory
conditions. For example, a strain of
, jC, has been maintained on adzuki beans in petri
dish for a variety of uses since 1936 when the original insects were collected in Kyoto, Japan.
Therefore,
C. chinensis
Wolbachia
infection in
C. chinensis
can be an excellent model system for understanding
the interactions and dynamics between
Wolbachia
and its host insect.
DETECTION OF
WOLBACHIA
FROM
C. CHINENSIS
In an attempt to survey endosymbiotic bacteria in bruchid beetles, 12 laboratory strains from seven
species Ð
Zabrotes subfasciatus
,
C. chinensis
,
C. maculatus
,
C. rhodesianus
,
Acanthoselides
obtetus
,
Bruchidius dorsalis
, and
Kytorhinus sharpianus
Ð were subjected to a polymerase-chain-
reaction (PCR) assay using primers for two
Wolbachia
genes,
ftsZ
and
wsp
(Figure 18.2). Positive
signals were detected only in strains of
C. chinensis
, whereas the other six species, including
congeneric
-negative.
To investigate the infection frequency in natural populations, 288 males and 334 females of
C. maculatus
and
C. rhodesianus,
were all
Wolbachia
C.
chinensis
collected from nine localities in Japan were subjected to the PCR assay. Surprisingly, all
the individuals examined were
Wolbachia
-positive, indicating that
Wolbachia
infection is probably
Ýxed in Japanese populations of
C. chinensis
.
SUPERINFECTION WITH THREE DISTINCT STRAINS
OF
WOLBACHIA
IN
C. CHINENSIS
To characterize the
Wolbachia
in
C. chinensis
, we ampliÝed, cloned, and sequenced the
wsp
gene
from individual insects. Unexpectedly, three distinct
sequences were reproducibly obtained
from all the individuals examined. Molecular phylogenetic analysis of these sequences unequivo-
cally indicated that
wsp
C. chinensis
was superinfected with three phylogenetically distinct
Wolbachia
strains (
Figure 18.3)
.
We designated these strains wBruCon, wBruOri, and wBruAus.
FIGURE 18.2
Diagnostic PCR detection of
Wolbachia
from laboratory strains of bruchid beetles. (A)
ftsZ
gene; (B)
wsp
gene. Lane 1,
Z. subfasciatus
C100 strain; lane 2,
Z. subfasciatus
US strain; lane 3,
C. chinensis
jC strain; lane 4,
C. chinensis
mrC97 strain; lane 5,
C. maculatus
hQ strain; lane 6,
C. maculatus
iQ strain;
lane 7,
C. rhodesianus
; lane 8,
A. obtectus
; lane 9,
B. dorsalis
Harataima strain; lane 10,
B. dorsalis
Tatsuno
strain; lane 11,
K. sharpianus
Mitsuma strain; lane 12,
K. sharpianus
Yoneyama strain; lane 13,
Ephestia
kuehniella
sp. (positive control); lane 14, without template (negative control); lane
M, DNA size markers (2000, 1500, 1000, 700, 500, 400, 300, 200 and 100 bps from top to bottom). [From
Kondo, N., Shimada, M., and Fukatsu, T. (1999).
infected with
Wolbachia
Zool. Sci.
16:
955Ï962. With permission.]
