Growth behaviour of two Trypanosoma cruzi strains in single and mixed infections:: In vitro and in the intestinal tract of the blood-sucking bug, Triatoma brasiliensis
Growth behaviour of two Trypanosoma cruzi strains in single and mixed infections:: In vitro and in the intestinal tract of the blood-sucking bug, Triatoma brasiliensis
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DOI：
10.1016/j.actatropica.2007.02.004
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发表时间：
2007-03-01
期刊：
影响因子：
2.7
通讯作者：
Jansen, Ana M.
中科院分区：
文献类型：
--
作者：
Araujo, Catarina A. C.;Cabello, Pedro H.;Jansen, Ana M.
竞争与合作是公认的生物现象，即使在寄生虫之间也是如此。寄生虫在单一宿主中的共感染导致几种结果，其中之一是对有限资源的竞争。在这里，混合感染的行为进行了评估，使用两个分离株的克氏锥虫，以前分型为属于基因型TcI和TcII。研究了巴西锥蝽的体外生长及在肠道不同部位的生长情况。体外培养结果显示，MDID/BR/1999/M1（TcI）倍增时间为19.5h，MIDID/BR/1999/JCPD 4（TcII）倍增时间为9.6h，而混合感染组倍增时间为13.9h。在体内实验中，分别进行了三组感染：M1/TcI、JCPD 4/TcII和混合感染（各占50%）。使用Kruskal-Wallis非参数检验进行组间的所有比较。结果表明，混合群体的体外培养与M1/Tc 1菌株的生长规律相似，表明M1/Tc 1菌株在无菌培养中具有正向选择性。在昆虫的肠道中，M1/Tcl分离株和混合感染主要定殖于直肠壁和直肠腔，而JCPD 4/TcII分离株主要定殖于小肠。根据所调查的分离株，可以得出结论，倍增时间不是共同感染的最终组成的决定性因素。此外，混合感染导致寄生虫的均匀分布，与单独研究的分离株相比。显然，在细菌的肠道中，JCPD 4/TcII分离物的同时存在导致来自M1/TcI的寄生虫数量的增加。(c)2007 Elsevier B. V.保留所有权利。
Competition and cooperation are well-recognized biological phenomena, even among parasites. Co-infection of parasites in a single host leads to several outcomes, one being competition for a limited resource. Here, the behaviour of mixed infection was evaluated using two isolates of Trypanosoma cruzi, previously typed as belonging to genotypes TcI and TcII. The growth in vitro and in the different compartments of the gut of Triatoma brasiliensis was studied. In vitro growth showed that MDID/BR/1999/M1 (TcI) has a doubling time of 19.5 h and MIDID/BR/1999/JCPD4 (TcII) of 9.6 h, while the mixed infection group presented a doubling time of 13.9 h. In vivo, three groups of infection were done: M1/TcI, JCPD4/TcII and mixed infection (50% of each strain), respectively. All comparisons among the groups were done using the Kruskal-Wallis non-parametric test. The data showed that the in vitro culture of mixed populations has a similar pattern to the growth of M1/TcI, apparently suggesting a positively selection for M1/Tcl strain, in axenic culture. In the gut of the insects, M1/Tcl isolate and mixed infections colonized predominantly the rectal wall and rectal lumen, in contrast to the JCPD4/TcII isolate, which was found mainly colonizing the small intestine. According to the isolates investigated, it could be concluded that the doubling time was not determinant factor for the final composition of a co-infection. Moreover, mixed infections resulted in a homogenous distribution of the parasites, comparing to the isolates studied separately. Apparently, in the gut of the bugs, the simultaneous presence of JCPD4/TcII isolate resulted in an improvement of the number of parasites from M1/TcI. (c) 2007 Elsevier B.V. All rights reserved.