RESUMEN
Protoporphyrinogen IX (Protogen IX) oxidase (PPO) catalyzes the oxidation of Protogen IX to Proto IX. PPO is also the target site for diphenyl ether-type herbicides. In plants, there are two PPO encoding genes, PPO1 and PPO2. To date, no PPO gene or mutant has been characterized in monocotyledonous plants. In this study, we isolated a spotted and rolled leaf (sprl1) mutant in rice (Oryza sativa). The spotted leaf phenotype was sensitive to high light intensity and low temperature, but the rolled leaf phenotype was insensitive. We confirmed that the sprl1 phenotypes were caused by a single nucleotide substitution in the OsPPO1 (LOC_Os01g18320) gene. This gene is constitutively expressed, and its encoded product is localized to the chloroplast. The sprl1 mutant accumulated excess Proto(gen) IX and reactive oxygen species (ROS), resulting in necrotic lesions. The expressions of 26 genes associated with tetrapyrrole biosynthesis, photosynthesis, ROS accumulation, and rolled leaf were significantly altered in sprl1, demonstrating that these expression changes were coincident with the mutant phenotypes. Importantly, OsPPO1-overexpression transgenic plants were resistant to the herbicides oxyfluorfen and acifluorfen under field conditions, while having no distinct influence on plant growth and grain yield. These finding indicate that the OsPPO1 gene has the potential to engineer herbicide resistance in rice.
Asunto(s)
Herbicidas , Oryza , Resistencia a los Herbicidas/genética , Herbicidas/farmacología , Mutación , Oryza/genética , Oryza/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Protoporfirinógeno-Oxidasa/genética , Protoporfirinógeno-Oxidasa/metabolismo , Especies Reactivas de OxígenoRESUMEN
OBJECTIVE: To determine the proportion of heroin use among patients who were involved in community-based methadone maintenance treatment (MMT) program and to identify the risk factors associated with heroin use. METHODS: This study was conducted in 9 MMT clinics within 3 provinces. Thirteen hundred and one patients who met the study criteria were selected from each of the five groups with different dosages of methadone users. An administrative questionnaire was applied to explore the demographics, drug abuse-related behaviors and MMT services received by the clients, etc. The prevalence of depression and anxiety among the clients were also collected by SAS and SDS. Urine samples were collected as a biological marker to indicate if heroin had been used. RESULTS: Of the 1301 patients, 76.2% were males. The mean age was (34.6 +/- 6.5) years while 71.7% had an education level of primary school or below. The average daily dosage of methadone was (48.1 +/- 29.4) mg and self-satisfied evaluation score on treatment was 8.6. On average, 27.7% urine samples showed positive opiate evidence. Marital status, employment status, treatment retention, self-satisfied evaluation score on dosage and dropout history were found to be significantly associated with heroin use, while gender, education level and dosage had no significant association with heroin use. It seemed that risk factors that associated with heroin use were different from areas to areas. CONCLUSION: High quality MMT clinic services, high self-satisfied score, longer treatment retention and low dropout rate seemed to have the effects of reducing the risk of ongoing heroin abuse under the methadone maintenance treatment program.