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  • 1
    ISSN: 0006-3592
    Keywords: Streptomyces virginiae ; autoregulator ; virginiae butanolide ; virginiamycin fermentation ; optimization ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A strategy for optimization of non-growth-associated production in batch culture employing an empirical approach was developed through the study of virginiamycin production. The strategy is formulated with two aims: attaining a high cell concentration at the beginning of the production phase without decrease in production activity; and enhancing the production activity during the production phase. As a practical example, the goal of a maximum virginiamycin (M and S) production in the batch culture of Streptomyces virginiae was set. To attain a high cell concentration in the production phase of the batch culture, that is, to extend the growth phase for as long as possible, the optimum composition and concentration of the complex medium, especially the yeast extract (YE) concentration, were first investigated. Dissolved oxygen (DO) concentration control was also a parameter considered in maintaining the production activity during the production phase. In addition, to enhance the production activity, an optimum addition strategy of an autoregulator, virginiae butanolide-C (VB-C), was investigated. Combining these measures, the optimum cultivation conditions were found to be an initial YE concentration in the complex medium of 45 g/L, the shot addition of 300 μg/L of VB-C 11.5 h after the start of the batch culture, and a DO concentration maintained above 2 mg/L. The maximum concentrations of virginiamycin M and S were about ninefold those obtained under nonoptimum cultivation conditions. Nonoptimum cultivation conditions consisted of an initial YE concentration one sixth (7.5 g/L) that of the optimum cultivation conditions, and no VB-C addition. These conditions were used as representative of the standard cultivation of virginiamycin in this study. The strategy developed here will be applicable to the production of other antibiotics, especially to the cultivation of Streptomyces species, in which a hormonelike signal material (an autoregulator) plays an important role in antibiotic production. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0006-3592
    Keywords: Streptomyces virginiae ; autoregulator ; virginiae butanolide ; virginiamycin fermentation ; optimization ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Virginiae butanolides (VBs) are autoregulators of Streptomyces virginiae, which induce virginiamycin biosynthesis. Generally, autoregulators are synthesized by the microorganism itself during culture. Addition of chemically synthesized virginiae butanolide-C (VB-C), which is one of the VBs, can also control the induction time and the amount of virginiamycin production. The optimum concentration and shot-feeding time of VB-C for the maximum production of virginiamycins M and S were investigated in flasks and jar-fermentor batch cultures. VB-C addition later than 8 h from the start of culture induced not only virginiamycin M and S synthesis but also VB synthesis. Virginiamycin M and S production increased with the decrease of total VBs (produced VBs and added VB-C) concentration. That is, although VBs are needed to induce virginiamycin M and S synthesis, the amount of VB-C added should be such that as small an amount as possible of VBs is synthesized to achieve the maximum production of virginiamycins M and S. However, the VB-C addition earlier than 8 h from the start of culture showed no clear relationship between the amounts of VBs and virginiamycins M and S produced. In conclusion, the maximum production of virginiamycins M and S was attained by the shot addition of 5 μg/L VB-C at 8 h from the start of culture. The maximum value was about twofold that without VB-C addition. The optimum addition strategy of VB-C was confirmed by the jar-fermentor experiments. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 303-306 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Xenon cluster ions (Xen+) were produced by multiphoton ionization at 266 nm of neutral clusters resulting from supersonic expansion of xenon gas. Metastable dissociations Xen+→Xen-1+ + Xe (where n=2-19) were observed by an angular reflectron time-of-flight mass spectrometer. Clusters of some particular sizes were found to be especially unstable, the highest dissociation rate obtained being for Xe14+. Furthermore, the dissociation rate tended to increase with increase of cluster size (n), in agreement with the evaporative ensemble model which has been developed by Klots.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 3 (1989), S. 355-357 
    ISSN: 0268-2605
    Keywords: Triphenylstibine oxide ; phosphorus pentasulfide ; catalytic peptide synthesis ; amidation ; thiocarboxylic acids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenylstibine oxide (Ph3SbO) and phosphorus(V) sulfide (P4S10) synergistically catalyzed the aminolysis of N-protected amino-acids with amino-acid esters in benzene. Ph3SbO accelerated both the initial conversion of carboxylic moieties into the corresponding thiocarboxylic moieties by P4S10 and the subsequent aminolysis of the resulting thiocarboxylic acids. Thus, dipeptides such as Z-A-A′-OEt (where Z = PhCH2OC(O)- and A,A′ = Ala,Gly; Gly,Gly; Leu,Gly; Phe,Gly; Phe,Leu;Ser,Gly; Val,Gly, respectively) were conveniently prepared even at 35°C.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2016-08-14
    Description: Paclitaxel is a standard second-line gastric cancer treatment in Japan. Trastuzumab could be active as second-line chemotherapy for taxane/trastuzumab-naïve patients with epidermal growth factor 2 (HER2)-positive advanced gastric cancer. Patients aged ≥20 years with HER2-positive, previously treated (except for trastuzumab and taxane), unresectable or recurrent gastric adenocarcinoma underwent combined trastuzumab (first and subsequent doses of 8 and 6 mg/kg, respectively, every 3 weeks) and paclitaxel (days 1, 8, 15, every 4 weeks) treatment. Study endpoints were best overall response, progression-free survival, overall survival, and safety. From September 2011 to March 2012, 47 Japanese patients were enrolled. Forty patients discontinued treatment after a median of 128.5 (range 4–486) days. Complete and partial responses were obtained in one and 16 patients (response rate of 37% [95% CI 23–52]), respectively. Median progression-free survival and overall survival were 5.1 (95% CI 3.8–6.5) and 17.1 (95% CI 13.5–18.6) months, respectively. Grade 3/4 adverse events were neutropenia (32.6%), leukopenia (17.4%), anemia (15.2%), and hypoalbuminemia (8.7%). There was no clinically significant cardiotoxicity or cumulative toxicity. Three (disturbed consciousness, pulmonary fibrosis, and rapid disease progression) grade 5 events occurred. In conclusion, trastuzumab combined with paclitaxel was well tolerated and was a promising regimen for patients with HER2-positive, previously treated, advanced or recurrent gastric cancer. This article is protected by copyright. All rights reserved.
    Print ISSN: 0020-7136
    Electronic ISSN: 1097-0215
    Topics: Biology , Medicine
    Published by Wiley-Blackwell
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