Environmental Engineering Reference
In-Depth Information
In this study we analyzed MSP1a repeat and microsatellite sequences in order to
provide information on the evolution of
A. marginale
strains by determining their phy-
logeographic association with world ecological regions (ecoregions) and by testing
the effect of different evolutionary pressures associated with the tick vector, mainly
R.
microplus
, ecology in these ecoregions.
MATERIALS AND METHODS
Anaplasma
marginale
MSP1a Repeat Sequences
The MSP1a sequences included in this study were obtained from
A. marginale
strains
collected worldwide from infected cattle and recently reviewed by de la Fuente et al.
[11]. The data on MSP1a sequences was updated by searching the Genbank sequence
database [21]. The amino acid sequence of the first (R1) and last (RL) MSP1a repeats
of 111
A. marginale
strains were used in this study, from which 39 and 28 unique R1
and RL sequences, respectively, were obtained. For comparison, the sequences of Rn
MSP1a repeats, located between R1 and RL, were included in some analyses. MSP1a
sequences not included in these studies were from
A. marginale
strains that were not
adequately geo-referenced.
Anaplasma
marginale
MSP1a Microsatellite Sequences
A microsatellite was located in the MSP1a 5'UTR between the putative Shine-Dalgarno
sequence (GTAGG; [6]) and the translation initiation codon (ATG). The structure of
the microsatellite (bold) was GTAGG (G/A TTT)m (GT)n T ATG (Table 1). The mic-
rosatellite was sequenced in 115
A. marginale
strains collected from infected cattle in
the USA, Canada, Mexico, Puerto Rico, Argentina, Brazil, Italy, Israel, South Africa,
and China [11].
Table 1.
Structure and ecoregion cluster distribution of the
A. marginale
MSP1a microsatellites.
Genotype Number of
strains
m
n
SD-ATG distance (nucleotides) Genotype frequency per ecoregion cluster
1
2
3
4
A
2
1
7
19
0.00
1.00
0.00
0.00
B
5
1
9
23
1.00
0.00
0.00
0.00
C
7
2
5
19
0.57
0.14
0.29
0.00
D
3
2
6
21
0.33
0.67
0.00
0.00
E
12
2
7
23
0.75
0.00
0.25
0.00
F
3
3
4
21
0.00
0.00
1.00
0.00
G
78
3
5
23
0. 15
0.14
0.56
0.14
H
3
3
6
25
0.00
0.67
0.33
0.00
I
Nl
4
6
29
...
...
...
...
The MSPI a microsatellite sequences were analyzed in 115 A. marginale strains. The microsatellite (sequence in bold)
was located between the Shine-Dalgarno (SD; sequence in brackets) and the translation initiation codon (ATG) with the
structure: GTAGG (G/A TTT)m (GT)n T ATG. The SD-ATG distance was calculated in nucleotides as (4 x m) + (2 x
n) + I. Abbreviation: Nl, not included in the study because the A. marginale strain was not adequately gee-referenced.
Search WWH ::
Custom Search