We examined the extent of variation of the 3' region of the circumsporozoite gene among Plasmodium falciparum isolates through amplification of a selected DNA fragment followed by DNA sequencing. A total of 32 isolates were analyzed, of which 24 were from Amazon endemic areas in Brazil and 8 from widely separated geographical regions in the world. Among Brazilian isolates only 2 variants were detected: 19 displayed the same sequence of strain 7G8 whereas the 4 remaining isolates differed from the 7G8 strain at five nucleotide positions which also led to amino acid changes. Variation was restricted to one of the T-helper epitopes while the sequence identified as a cytotoxic T cell epitope was conserved in all Brazilian isolates. P. falciparum samples from other geographical regions in the world showed sequences distinct from those of Brazilian isolates. However, some constancy could be observed within that variation. For instance, the most frequent nucleotide substitutions, from A and C at nucleotide positions 1015 and 1024, were the same in all isolates.

译文

我们通过扩增选定的DNA片段,然后进行DNA测序,检查了恶性疟原虫分离株中环子孢子基因3' 区域的变异程度。共分析了32个分离株,其中24个来自巴西的亚马逊流行地区,8个来自世界上广泛分离的地理区域。在巴西分离株中,仅检测到2个变体: 19个显示了相同的7G8菌株序列,而其余4个分离株在五个核苷酸位置与7G8菌株不同,这也导致了氨基酸变化。变异仅限于T辅助表位之一,而在所有巴西分离株中,被鉴定为细胞毒性T细胞表位的序列都是保守的。来自世界其他地理区域的恶性疟原虫样品显示出与巴西分离株不同的序列。但是,在该变化中可以观察到一些恒定性。例如,在所有分离物中,来自核苷酸位置1015和1024处的A和C的最频繁的核苷酸取代是相同的。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录