Fachgebiet für Pflanzenphysiologie, Department für Pflanzenwissenschaften, Technische Universitaet Muenchen, am Hochanger 4, 85354 Freising, Germany.
Syst Appl Microbiol. 2010 Jan;33(1):25-34. doi: 10.1016/j.syapm.2009.10.002. Epub 2009 Dec 3.
Using fluorescence in situ hybridization (FISH) techniques and PCR-based rDNA sequencing, gut microflora in the larvae of bark- and wood-inhabiting cerambycid beetles (Rhagium inquisitor, Tetropium castaneum, Plagionotus arcuatus and Leptura rubra [Coleoptera: Cerambycidae]) was investigated. A total of 12 novel ascomycetous yeast strains were isolated from the gut content. Panfungal and strain-specific oligonucleotide probes identified two yeast strains as Candida rhagii and Candida shehatae, which were colonizing specialized organs (mycetomes) adhering to the gut of R. inquisitor and L. rubra larvae, respectively. Fragments containing these organisms were constantly being released from the mycetomes into the gut lumen. Whereas the mycetome symbiont of T. castaneum could not be identified, all larvae of this species harbored an additional bacterial endocytobiont in their gut epithelium. This novel gammaproteobacterium belonged to the Sodalis clade of insect symbionts, which includes the secondary endosymbiont of tsetse flies (Sodalis glossinidius) and the Sitophilus oryzae primary endosymbiont (SOPE). Extracellular gut flora of the investigated cerambycid larvae was comprised of Alpha-, Beta-, and Gammaproteobacteria, Actinobacteria, Firmicutes, Verrucomicrobia and Acidobacteria. However, the individual composition among investigated larvae was highly variable and supposedly depended on individual host nutrition.
采用荧光原位杂交（FISH）技术和基于 PCR 的 rDNA 测序，研究了树皮和木材栖甲虫幼虫（Rhagium inquisitor、Tetropium castaneum、Plagionotus arcuatus 和 Leptura rubra [鞘翅目：天牛科]）的肠道微生物群。从肠道内容物中总共分离出 12 株新型子囊菌酵母菌株。泛真菌和菌株特异性寡核苷酸探针将两株酵母鉴定为 Candida rhagii 和 Candida shehatae，它们分别定植于专门的器官（mycetomes），附着在 R. inquisitor 和 L. rubra 幼虫的肠道上。含有这些生物的片段不断从 mycetomes 释放到肠道腔中。虽然 T. castaneum 的 mycetome 共生体无法鉴定，但该物种的所有幼虫在其肠道上皮中都有另一种细菌内共生体。这种新型γ变形菌属于昆虫共生体的 Sodalis 分支，其中包括采采蝇的次生内共生体（Sodalis glossinidius）和 Sitophilus oryzae 的初级内共生体（SOPE）。研究的天牛幼虫的肠道外菌群由α、β和γ变形菌、放线菌、厚壁菌门、疣微菌门和酸杆菌门组成。然而，调查幼虫之间的个体组成差异很大，可能取决于个体宿主的营养状况。
