The general secretory (Sec) pathway represents a common mechanism by which bacteria secrete proteins, including virulence factors, into the extracytoplasmic milieu. However, there is little information about this system, as well as its associated secretory proteins, in relation to the fire blight pathogen Erwinia amylovora. In this study, data mining revealed that E. amylovora harbors all of the essential components of the Sec system. Based on this information, we identified putative Sec-dependent secretory proteases in E. amylovora on a genome-wide scale. Using the programs SignalP, LipoP, and Phobius, a total of 15 putative proteases were predicted to contain the N-terminal signal peptides (SPs) that might link them to the Sec-dependent pathway. The activities of the predicted SPs were further validated using an Escherichia coli-based alkaline phosphatase (PhoA) gene fusion system that confirmed their extracytoplasmic property. Transcriptional analyses showed that the expression of 11 of the 15 extracytoplasmic protease genes increased significantly when E. amylovora was used to inoculate immature pears, suggesting their potential roles in plant infection. The results of this study support the suggestion that E. amylovora might employ the Sec system to secrete a suite of proteases to enable successful infection of plants, and shed new light on the interaction of E. amylovora with host plants.
Erwinia amylovora/metabolism* ; Escherichia coli/genetics* ; Peptide Hydrolases/genetics* ; Plant Diseases/microbiology* ; Pyrus/microbiology*

PURPOSE: L-asparaginase is a crucial chemotherapeutic agent for the treatment of acute lymphoblastic leukemia. However, hypersensitivity to L-asparaginase is common which limits its clinical use. METHODS: We performed 44 cases of premedication and 3 cases of desensitization in 16 patients with hypersensitivity to L-asparaginase. RESULTS: With premedication, 33 cases completed L-asparaginase injection with no hypersensitivity reactions. Eleven cases showed mild hypersensitivity reactions, such as urticaria. Desensitization was performed in 3 cases: in 2 cases, desensitization was successful, and in 1 case the medication was switched to Erwinia asparaginase. CONCLUSION: Premedication and desensitization appear to be useful in helping patients receive desired doses of L-asparaginase in pediatric patients with acute lymphoblastic leukemia.
Asparaginase ; Desensitization, Immunologic ; Drug Hypersensitivity ; Erwinia ; Humans ; Hypersensitivity* ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; Premedication* ; Urticaria

PURPOSE: We evaluated the frequency and clinical characteristics of the side effects of L-asparaginase during treatment of childrens with acute lymphoblastic leukemia (ALL) & Non-Hodgkin lymphoma (NHL). METHODS: Medical records of children who were treated as 37 ALL and 3 NHL in Korea University Medical Center from January 1995 to June 1998 were reviewed. RESULTS: 1) The 40 patients (21 males and 19 females) had a mean age of 6.2+/-3.3 (range, 0.4~12.8). 2) Nine (7 ALL, 2 NHL) of these 40 patients (median: 5.0 years, range: 3.8~11.5 years) had side reactions (5 hypersensitivity, 2 hyperglycemia, 1 pancreatitis, 1 CNS abnormality) to Escherichia coli L-asparaginase. 3) The hypersensitivity reactions to E. coli asparaginase were the most common side effects. Erwinia asparaginase administered to those patients without side reactions. 4) The range of doses of E. coli asparaginase received prior to experiencing any hypersensitivity was 10 to 22 times. 5) Other reactions (hyperglycemia, pancreatitis and CNS abnormality) were developed at early diseases state and completely recovered. CONCLUSION: We found Erwinia asparaginase to be an acceptable substitute for E. coli asparagianse for childrens who had hypersensitivity reactions. In our experience, hypersensitivity reactions are do not detected in inducton therapeutic period. But, We recommend that you should carefully observe your patients during the early induction period.
Academic Medical Centers ; Asparaginase ; Child ; Erwinia ; Escherichia coli ; Humans ; Hyperglycemia ; Hypersensitivity ; Korea ; Leukemia ; Lymphoma ; Lymphoma, Non-Hodgkin ; Male ; Medical Records ; Pancreatitis ; Precursor Cell Lymphoblastic Leukemia-Lymphoma

Studies on lycopene synthesis in Escherichia coli were not only able to gain the strains with high yield and less by-products, but also able to test functions of genes or gene clusters. In this article, the cDNA sequences of tomato LeGGPS2 and LePSY1 as well as the coding sequence of crtI from Erwinia uredovora, each of which was added a ribosome biding site, were controlled by T7 promoter and terminator alone or combined, and expressed in E. coli BL21 (DE3) to induce lycopene synthesis. The results show that only T7::crtI-LeGGPS2-LePSY1 expressed tri-cistronically could produce lycopene, and 2.124 mg/g dry cell weight oflycopene was obtained when fermented for 5 h at 30 degrees C after mixing 80 micromol/L IPTG at the later logarithmic phase while the seed broth of 1:50 (V/V) was inoculated into LB medium (pH 6.8) containing 3% sucrose and cultured for 8 h at 37 degrees C. The results confirmed the function of the prokaryonized LeGGPS2 and LePSY1 and their synergy with crtI, and also laid a foundation to establish an independent lycopene synthetic pathway in the tomato plastid.
Bacterial Proteins ; genetics ; Carotenoids ; biosynthesis ; genetics ; Cloning, Molecular ; Erwinia ; genetics ; Escherichia coli ; genetics ; metabolism ; Genetic Engineering ; Plant Proteins ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics