DNA-SYNTHESIS IN PLASMODIUM-BERGHEI DURING ASEXUAL AND SEXUAL DEVELOPMENT
DNA-SYNTHESIS IN PLASMODIUM-BERGHEI DURING ASEXUAL AND SEXUAL DEVELOPMENT
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DOI：
10.1016/0166-6851(86)90029-0
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发表时间：
1986-08-01
影响因子：
1.5
通讯作者：
OVERDULVE, JP
中科院分区：
文献类型：
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作者：
JANSE, CJ;VANDERKLOOSTER, PFJ;OVERDULVE, JP
采用Fuelgen-pararosaniline（SO_2）染色法，用直接免疫荧光法测定伯氏疟原虫各期DNA含量。子孢子、红细胞内环状体和滋养体（直到侵入后至少15小时）是单倍体和非合成DNA。DNA在胚胎发育前和过程中合成，需要4-6小时。基因组复制和分离在整个过程中交替发生。成熟的小配子母细胞和大配子母细胞的DNA含量在单倍体和二倍体值之间;如果不是全部，也是大多数超过单倍体值的DNA是在成熟的最后5-10小时合成的。在配子发生过程中，小配子体在8-10 min内稳定地合成DNA，并以极高的速率合成DNA，超过四倍体值，而大配子体的DNA含量保持不变。体外受精发生在配子形成后1小时内。在2小时内，与减数分裂的开始相一致，合子然后合成DNA几乎达到四倍体值，之后在动合子发育期间合成停止。所有上述DNA合成过程都被阿非迪霉素（C50为3-13 μ M）可逆地抑制。根据小配子发生过程中的DNA合成速率，我们计算出伯氏疟原虫单倍体基因组中至少有1300个复制起点。
DNA contents of individual stages of Plasmodium berghei were measured by direct immunofluorometry after Fuelgen-pararosaniline (SO2) staining. Sporozoites, intra-erythrocytic ringforms and trophozoites (until at least 15 h after invasion) are haploid and non-synthesizing DNA. DNA is synthesized just before and during schizogony, which takes 4-6 h. Genome duplication and segregation are alternating events throughout this process. Mature micro- and macrogametocytes have DNA contents between the haploid and diploid value; most, if not all of the DNA in excess of the haploid value is synthesized during the last 5-10 h of maturation. Durig gametogenesis microgametocytes within 8-10 min synthesize DNA steadily and at a very high rate to more than the octoploid value while the DNA content of macrogametocytes remains constant. Fertilization in vitro takes place within 1 h after gamete formation. Within 2 h and coinciding with the onset of meiosis the zygote then synthesizes DNA up to almost the tetraploid value, after which synthesis stops during ookinete development. All the above mentioned processes of DNA synthesis are reversibly inhibited by aphidicolin (C50 from 3-13 .mu.M). From the rate of DNA synthesis during microgametogenesis we calculated a minimum of 1300 origins of replication in the haploid genome of P. berghei.