Tissue tropism, transmission and expression of foreign genes in vivo in midgut symbionts of tsetse flies
Tissue tropism, transmission and expression of foreign genes in vivo in midgut symbionts of tsetse flies
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DOI：
10.1046/j.1365-2583.1999.810125.x
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发表时间：
1999-02-01
影响因子：
2.6
通讯作者：
Aksoy, S
中科院分区：
文献类型：
--
作者：
Cheng, Q;Aksoy, S
采采蝇（双翅目：舌蝇科）除了传播致病性非洲锥虫外，还携带三种不同的共生生物。两种与肠道相关的共生体（初级，P；次级，S）是肠内的，并且需要营养，而第三种微生物沃尔巴克氏体（立克次体科）会影响其感染的昆虫的生殖生物学。细菌组相关的 P 共生体（Wigglesworthia glsinidia）与其宿主采采蝇物种表现出一致的系统发育，而以遥远的采采蝇为特征的中肠 S 共生体具有相同的 16S rDNA 序列，因此可能代表最近的独立获得或物种之间的水平转移。 S-共生体已在体外培养，并开发了遗传转化系统。在这里，我们报告了它们在不同物种（G、m. morsitans、G. p、须须、G. austeni 和 G. brevipalpis）中的密度和组织向性，以及它们向采采蝇后代的母体传播途径。使用细菌特异性 PCR 检测，S 共生体主要存在于淡色苍蝇的中肠、血淋巴、乳腺中，而 G 触须也存在于苍蝇的唾液腺中。在苍蝇中，这些感染被发现扩散到她的组织，包括肌肉、睾丸和脂肪体。 S-共生体被转化以在体外表达标记基因产物绿色荧光蛋白（GFP），当通过胸腔内显微注射将重组共生体引入可育雌性果蝇的血囊时，它们在子宫内后代中被检测到，表明血淋巴可能为其传播提供了可能的途径。讨论了这些结果对共生体-宿主相互作用和采采蝇转基因策略的影响。
Tsetse flies (Diptera: Glossinidae) harbour three different symbiotic organisms in addition to the pathogenic African trypanosomes they transmit. The two gut-associated symbionts (primary, P; secondary, S) are enteric and are nutritionally required, whereas the third microorganism Wolbachia (family Rickettsiaceae) affects the reproductive biology of the insects it infects. The bacteriome-associated P-symbiont (Wigglesworthia glossinidia) displays a concordant phylogeny with its host tsetse species, whereas midgut S-symbionts characterized from distant tsetse have identical 16S rDNA sequences and therefore may either represent recent independent acquisitions or horizontal transfer between species. The S-symbionts have been cultured in vitro and a genetic transformation system has been developed. Here we report on their density and tissue tropism in different species (G, m. morsitans, G. p, palpalis, G. austeni and G. brevipalpis) and on their maternal route of transmission to tsetse progeny. Using a bacterium-specific PCR-assay, the S-symbionts were found primarily in the midgut, haemolymph, milk gland and in G, palpalis also in salivary glands of teneral flies, In order flies these infections were found to spread to of her tissues including muscle, testes and fat body. The S-symbionts were transformed to express the marker gene product, Green Fluorescent Protein (GFP) in vitro, When the recombinant symbionts were introduced into the haemoceal of fertile female flies via intrathoracic microinjection, they were detected in the intrauterine progeny, indicating that haemolymph may provide a possible route for their transmission, The implications of these results for symbiont-host interactions and for transgenic strategies in tsetse are discussed.