No abstract

Mitochondrial DNA (mtDNA) mutations are found in many types of cancers and suspected to be involved in carcinogenesis, although the mechanism has not been elucidated. In this study, we report that consecutive C-to-T mutations (hypermutations), a unique feature of mutations induced by APOBECs, are found in mtDNA from cervical dysplasia and oropharyngeal cancers. In vitro, we found that APOBEC3A (A3A) and 3B (A3B) expression, as well as mtDNA hypermutation, were induced in a cervical dysplastic cell line W12 when cultured in a differentiating condition. The ectopic expression of A3A or A3B was sufficient to hypermutate mtDNA. Fractionation of W12 cell lysates and immunocytochemical analysis revealed that A3A and A3B could be contained in mitochondrion. These results suggest that mtDNA hypermutation is induced upon keratinocyte differentiation, and shed light on its molecular mechanism, which involves A3s. The possible involvement of mtDNA hypermutations in carcinogenesis is also discussed.

Various neural systems cooperate in feeding behaviour, and olfaction plays crucial roles in detecting and evaluating food objects. While odour-mediated feeding behaviour is highly adaptive and influenced by metabolic state, hedonic cues and learning processes, the underlying mechanism is not well understood. Feeding behaviour is regulated by orexigenic and anorexigenic neuromodulatory molecules. However, knowledge of their roles especially in higher olfactory areas is limited. Given the potentiation of feeding behaviour in hunger state, we systemically examined the expression of feeding-related neuromodulatory molecules in food-restricted mice through quantitative PCR, in the olfactory bulb (OB), olfactory tubercle (OT), and remaining olfactory cortical area (OC). The OT was further divided into attraction-related anteromedial, aversion-related lateral and remaining central regions. Examination of 23 molecules including neuropeptides, opioids, cannabinoids, and their receptors as well as signalling molecules showed that they had different expression patterns, with many showing elevated expression in the OT, especially in the anteromedial and central OT. Further, in mice trained with odour-food association, the expression was significantly altered and the increase or decrease of a given molecule varied among areas. These results suggest that different olfactory areas are regulated separately by feeding-related molecules, which contributes to the adaptive regulation of feeding behaviour.

This study attempted to understand the effects of BAP and ethrel on organogenesis of protocorm-like bodies (PLBs) in Dendrobium kingianum under white fluorescent lamps in vitro. BAP is the most effective cytokinin for multiplication in plant tissue culture. Ethrel regulates many aspects of plant morphogenesis. The highest number of PLBs (13.1) as against in control (8.1) and the highest number of developing shoots (2.1) was recorded in the medium containing 0.1 mg/l BAP combined with 1 mg/l ethrel. Increase in fresh weight showed higher values in same combination. Low concentration of BAP alone increased in the number of PLBs but showed inhibitory effects on shoot formation. On the other hand low concentration of ethrel alone increased both number of PLBs and shoots after 4 weeks in vitro.Dendrobium is popular in the international floriculture industry due to its floriferous flower sprays, wide spectrum of colors, sizes and shapes; year-round availability and long flowering life ( Kuehnle 2007, Khosravi et al. 2009). BAP is the most effective cytokinin for multiplication followed by Kn and 2-ip (Hu and Wang 1983, Schuch andErig 2005). Ethylene is unique among plant hormones; it is a simple hydrocarbon that affects growth, differentiation, and senescence in plants in concentrations as low as 0.01 µl/l (Reid 1995). Ethylene regulates many aspects of plant morphogenesis. Growth and development of cells cultured in vitro are largely dependent on the presence of phytohormones. Hence, modification of phytohormone composition and interaction in the nutrient medium has been the primary strategy to manipulate morphogenesis in vitro. Research on specific effects of ethylene on cell division is rather limited. From the