Red meats are important animal foods because of their nutritional aspects, but the over-consumption of red meat produces reactive oxygen species (ROS) caused by heme iron and induces colorectal cancer. The effect of orally administered hemin and calcium provided in drinking water for 6 weeks on colon carcinogenesis was observed in male ICR mice. After the mice were acclimated for 1 week, they received three subcutaneous azoxymethane (AOM, 10 mg/kg b.w.) injections weekly and were provided with 2% dextran sodium sulfate (DSS) via drinking water for the next week. The mice were divided into three groups: the control, hemin, and hemin + calcium groups. The orally administered daily dose of hemin was 2 g/kg b.w., and 0.05% calcium was provided daily via drinking water. Colonic mucosa samples were stained with methylene blue, and then, the numbers of aberrant crypt (AC) and aberrant crypt foci (ACF) were counted. Lipid peroxidation in feces was estimated by thiobarbituric acid-reactive substances (TBARS) assay. The total numbers of AC and ACF per colon in the hemin group were significantly higher than those in the control group. Calcium treatment significantly decreased the numbers of ACF and AC in the colon of mice. The TBARS value in the feces of the hemin + calcium group was significantly lower than that in the feces of the hemin group. These results showed that hemin enhances the formation of pre-neoplastic lesions in the colon of mice and that calcium decreases the risk of colon carcinogenesis.
The control of flowering, transition from vegetative to reproductive stage, is crucial for significant success during plant development. Multiple environmental and developmental signals are transmitted to the shoot apical meristem and converted to local cue to process developmental phage. These crucial process are delicately controlled and regulated by expression of tissue specifically expressed genes involved in inflorescence development. Therefore, it is necessary that molecular mechanism associated with inflorescence development is revealed to understand control of flowering by genome-wide expression pattern of inflorescence specific genes. In this study we used Affymetrix GeneChip Wheat Genome Array for genome-wide analysis of the expressed genes of inflorescence development including apical meristem and developing spikelet to understand the mechanism of floral development in early stage of wheat inflorescence. Moreover, meta-analysis of 1479 microarray dataset of GPL 3802 provided by Gene Expression Omnibus (GEO) was conducted to determine expression pattern of each probe throughout whole life cycle. Based on meta-analysis, we demonstrate inflorescence specific expressed genes in wheat inflorescence including apical meristem, spikelet meristem to understand the mechanism of floral development of wheat inflorescence.
Over the last decades, increasing natural disasters and climate change are considered as the major environmental problems facing the globe. Numerous studies have been indicated it would cause huge losses on agriculture, especially in the grain productivity. Therefore, several alternatives are suggested for boosting up productivity of wheat as one of the main human food crop. One of important strategy is proper management of inflorescence development and DELLA proteins have been elucidated to play pivotal roles in growth of many plant organs. In this study, putative negative regulator of DELLA protein, GAST (Gibberellic acids stimulated transcript) have been isolated to identify their role in the developing spike of wheat. Four genes were isolated from its gene family and designated as TaGAST1, 2, 3, 4. Genomic structure was analyzed to demonstrate chromosomal localization of TaGAST genes and evolutionary relationships were also verified with GAST genes in other plant species. RT-PCR was conducted to detect transcriptional changes of TaGAST genes on external phytohormone. Each of TaGAST genes showed considerable changes in transcription level after GA, ABA, PAC treatment, respectively. Through Yeast two-hybrid assay, one protein for TaGAST1, and four proteins for TaGAST2 was isolated as putative interactive proteins in wheat spikes just before and after emergence.
Protein disulfide isomerase (PDI) is a chaperone protein that involves in oxidative protein folding by acting as catalysts and folding assistants in the endoplasmic reticulum (ER). Genome database showed that rice contains three PDI-like genes. But, their functions and subcellullar localization are not clearly identified. Here, we show possible functions of rice PDI (OsPDI) during seed development. Seeds of OsPDI T-DNA insertion mutants which were identified by genomic DNA PCR and western blot display chalky phenotype. Electron microscope analysis revealed that endosperms of the OsPDIL1-1Δ mutant show imperfect packing of round starch granules, causing floury-white color. Abnormal form of protein body I (PB-I) containing prolamin and thick aleurone layer were also observed in the OsPDIL1-1Δ mutants. Protein content per seed was significantly low in the OsPDIL1-1Δ mutant. However, free sugar content was high in the OsPDIL1-1Δ mutant seed. Northern and western blot analyses showed that during seed development, OsPDI protein is steadily accumulated in the seed until maturation while its transcript level was highest at 10 days after flowering and rapidly decreased to basal level. In addition, OsPDI strongly interacts with cysteine protease OsCP1 and chaperone BiP protein accumulates in OsPDIL1-1Δ mutant. Besides, proteomic analysis of the OsPDIL1-1Δ mutant seed showed that OsPDI is post-translationally regulated and its loss causes accumulation of many types of seed proteins. Our results indicate that OsPDI plays a critical role in seed development through its regulatory activity for various proteins.
Grain yield, one of the most important agronomic traits, is greatly affected by architecture in rice. Here, we show that an OsPrMC3, a rice PrMC3 orthologue with a lipase or esterase domain, involves in yielding by tillering. Phenotypic analysis of T-DNA insertion mutant revealed that it has high number of tillers than wild type although height and leaf width are shorter and narrower than wild type. Size and branch number of panicle were greatly reduced in the mutant, which resulted in significant decrease of seed number per panicle and dry weight of the seeds. OsPrMC3 is highly expressed in the leaf during the early stage of development. However, it is mainly expressed in mature seed and root after flowering although its expression is detected in all of the tissues. Our result indicates that OsPrMC3 involves in leaf growth and tillering during vegetative growth and also seed development after flowering, suggesting its crucial regulatory role in yielding
Rye has important genes for biotic and abiotic stress resistance. Introduction of these genes to wheat by breeding wheat-rye translocation have been intensively used in wheat breeding program. Rye chromatin 1RS and/or 2RL show superior performance in unfavorable environments. In order to develop high yielding wheat, we applied various molecular breeding strategies. To develop EST-derived 1RS specific markers, we used comparative genomics with public sequence databases of Poaceae family. Putative rye chromatin specific sequences were used to design 1RS specific markers. To identify genes related to water deficiency, cDNA AFLP analysis was used in PEG treated seedlings of 1RS RILs. For functional analysis of identified genes and markers, we used Brachypodium distachyon, as a new model plant of temperate grasses. B. distachyon were recently applied for transformation and we constructed Agrobacterium-mediated transformation system. Integration of those strategies and conventional breeding method would enhance the usefulness of rye chromatins for wheat improvement.
Brachypodium distachyon is rapidly emerged in biological study and has been currently used as a model system for genetics and functional studies for crop improvement and biofuel production. Phosphinothricin (PPT) has been widely used as a selectable agent, which raises ammonium content and induces toxicity in non-transformed plant cells. However PPT selection is not much effective on Brachypodium callus consequently reducing transformation efficiency. In order to identify the efficient conditions of PPT selection, calli obtained from mature seeds of Brachypodium (PI 254867) were cultured on the callus inducing medium (CIM) or regeneration medium (ReM) containing serial dilutions of the PPT (0, 2, 5, 10, and 15 mg/l) in dark or light condition. Callus growth and ammonium content of each treatment were measured 2 weeks after the treatment. Although callus growth and ammonium content did not show much difference in CIM, slow callus growth and increased ammonium accumulation were found in ReM. No significant difference of ammonium accumulation in response to PPT was found between dark and light conditions. In order to identify major factors affecting increased ammonium accumulation, callus was cultured on the media in combined with phytohormones (2,4-D or kinetin) and carbon sources (sucrose or maltose) containing with PPT (5 mg/l). The highest ammonium content in callus was found in the kinetin and maltose media.