Impact of Reduced Acidic Earwax pH and Earwax-Determinant Genotypes in Acquired Middle Ear Cholesteatoma.

OBJECTIVE: The development of acquired middle ear cholesteatoma is associated with a single nucleotide polymorphism, 538G>A, in the human adenosine triphosphate-binding cassette transporter C11 (ABCC11) gene, which is a determinant of the earwax morphotype, such as wet- and dry-type earwax; however, the mechanism underlying this association is unclear. We focused on the earwax pH and aimed to elucidate the mechanism between ABCC11 genotypes and acquired middle ear cholesteatoma. STUDY DESIGN: Prospective observational study. SETTING: Single-center, academic hospital. METHODS: We recruited 40 patients with acquired middle ear cholesteatoma who underwent surgery and 115 controls with no history of middle ear cholesteatoma. We assessed the earwax pH and ABCC11 genotypes in all participants. Clinical information was collected from the patients with cholesteatoma. RESULTS: The earwax pH was significantly less acidic in patients with cholesteatoma and those carrying wet earwax genotypes (ABCC11 538G/G or 538G/A) than in the controls and those carrying the dry earwax genotype (ABCC11 538A/A), respectively. Furthermore, earwax pH was significantly positively correlated with high preoperative cholesteatoma stages in the patients with cholesteatoma. CONCLUSION: Our results show that the less acidic earwax pH was significantly related to the development and progression of acquired middle ear cholesteatoma. The less acidic earwax pH may play an important role in the mechanism underlying the association between acquired middle ear cholesteatoma and the ABCC11 gene at site 538.

Reprogramming of the Developmental Program of Rhus javanica During Initial Stage of Gall Induction by Schlechtendalia chinensis.

Insect galls are unique organs that provide shelter and nutrients to the gall-inducing insects. Although insect galls are fascinating structures for their unique shapes and functions, the process by which gall-inducing insects induce such complex structures is not well understood. Here, we performed RNA-sequencing-based comparative transcriptomic analysis of the early developmental stage of horned gall to elucidate the early gall-inducing process carried out by the aphid, Schlechtendalia chinensis, in the Chinese sumac, Rhus javanica. There was no clear similarity in the global gene expression profiles between the gall tissue and other tissues, and the expression profiles of various biological categories such as phytohormone metabolism and signaling, stress-response pathways, secondary metabolic pathways, photosynthetic reaction, and floral organ development were dramatically altered. Particularly, master transcription factors that regulate meristem, flower, and fruit development, and biotic and abiotic stress-responsive genes were highly upregulated, whereas the expression of genes related to photosynthesis strongly decreased in the early stage of the gall development. In addition, we found that the expression of class-1 KNOX genes, whose ectopic overexpression is known to lead to the formation of de novo meristematic structures in leaf, was increased in the early development stage of gall tissue. These results strengthen the hypothesis that gall-inducing insects convert source tissues into fruit-like sink tissues by regulating the gene expression of host plants and demonstrate that such manipulation begins from the initial process of gall induction.

A biological timer in the fat body comprising Blimp-1, ßFtz-f1 and Shade regulates pupation timing in Drosophila melanogaster.

During the development of multicellular organisms, many events occur with precise timing. In Drosophila melanogaster, pupation occurs about 12 h after puparium formation and its timing is believed to be determined by the release of a steroid hormone, ecdysone (E), from the prothoracic gland. Here, we demonstrate that the ecdysone-20-monooxygenase Shade determines pupation timing by converting E to 20-hydroxyecdysone (20E) in the fat body, which is the organ that senses nutritional status. The timing of shade expression is determined by its transcriptional activator ßFtz-f1. The ßftz-f1 gene is activated after a decline in the expression of its transcriptional repressor Blimp-1, which is temporally expressed around puparium formation in response to a high titer of 20E. The expression level and stability of Blimp-1 is critical for the precise timing of pupation. Thus, we propose that Blimp-1 molecules function like sand in an hourglass in this precise developmental timer system. Furthermore, our data suggest that a biological advantage results from both the use of a transcriptional repressor for time determination and the association of developmental timing with nutritional status of the organism.