We have isolated and studied the organization of Streptomyces hygroscopicus genes responsible for the biosynthesis of the antibiotic herbicide bialaphos. Bialaphos production genes were cloned from genomic DNA using a plasmid vector (pIJ702). Three plasmids were isolated which restored productivity to S. hygroscopicus mutants blocked at different steps of the biosynthetic pathway. Subcloning experiments using other nonproducing mutants showed that four additional bialaphos production genes were also contained on these plasmids. A gene conferring resistance to bialaphos, which was independently cloned using the plasmid vector plJ61, and an antibiotic-sensitive host (S. lividans), was also linked to the production genes. Cosmids were isolated which defined the location of these genes in a 16 kb cluster.

We have constructed a chimeric gene consisting of the promoter, first exon, and first intron of a maize ubiquitin gene Although the production of transgenic rice plants has been reported by a number of laboratories (1,4,6,13,17,19,24,26,28,30), the regeneration of fertile, stably transformed rice has yet to be made routine and efficient.In many plant transformation studies, drug resistance genes such as neomycin phosphotransferase or hygromycin phosphotransferase have been used as selectable markers (19,24,25,28). One recent altemative strategy that has emerged is based on the use of marker genes that confer resistance to herbicides (7,8,10,11).

Summary Systemic acquired resistance (SAR), a natural disease response in plants, can be induced chemically. Salicylic acid (SA) acts as a key endogenous signaling molecule that mediates SAR in dicotyledonous plants. However, the role of SA in monocotyledonous plants has yet to be elucidated. In this study, the mode of action of the agrochemical protectant chemical probenazole was assessed by microarray‐based determination of gene expression. Cloning and characterization of the most highly activated probenazole‐responsive gene revealed that it encodes UDP‐glucose:SA glucosyltransferase (OsSGT1), which catalyzes the conversion of free SA into SA O‐β‐glucoside (SAG). We found that SAG accumulated in rice leaf tissue following treatment with probenazole or 2,6‐dichloroisonicotinic acid. A putative OsSGT1 gene from the rice cultivar Akitakomachi was cloned and the gene product expressed in Escherichia coli was characterized, and the results suggested that probenazole‐responsive OsSGT1 is involved in the production of SAG. Furthermore, RNAi‐mediated silencing of the OsSGT1 gene significantly reduced the probenazole‐dependent development of resistance against blast disease, further supporting the suggestion that OsSGT1 is a key mediator of development of chemically induced disease resistance. The OsSGT1 gene may contribute to the SA signaling mechanism by inducing up‐regulation of SAG in rice plants.

OBJECTIVES: To determine the effectiveness of surveillance colonoscopy (SC) and optimize its use by assessing real-world surgically resected cases of ulcerative colitis (UC)-associated colorectal cancer (CRC) and dysplasia. METHODS: Clinicopathological data of 406 (238 CRC and 168 dysplasia) patients who underwent surgical resection in 10 UC specialized institutions were retrospectively reviewed. The overall survival (OS) rates were compared between the SC and non-SC groups. The incidence of and risk factors for early-onset CRC (<8 years after UC onset) were identified. The distribution of CRC lesions was also assessed. RESULTS: Cancer stages were significantly more advanced in the non-SC group than in the SC group (P < 0.001). The patients in the SC group showed significantly better OS than those in the non-SC group (5-year OS: 89% vs 70%; log-rank test: P = 0.001). Seventeen percent of patients developed CRC within 8 years after UC onset. The age at UC onset was a risk factor and a good predictor of early-onset CRC (<8 years) (P < 0.01; AUC: 0.85). The most common sites of CRC were the rectum (51%) and sigmoid colon (20%). Multiple CRC was identified in 16% of patients. CONCLUSIONS: Surveillance colonoscopy was effective and improved the OS in patients with UC. We recommend that patients with late-onset UC (>40 years) undergo SCs earlier because of the high incidence of CRC within 8 years of UC onset. Moreover, the rectum and sigmoid colon should be more thoroughly examined.

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