scholarly journals Optimization of growth medium and fermentation conditions for improved antibiotic activity of Xenorhabdus nematophila TB using a statistical approach

2010 ◽  
Vol 9 (47) ◽  
pp. 8068-8077 ◽  
Author(s):  
L Fang X ◽  
T Feng J ◽  
G Zhang W ◽  
H Wang Y ◽  
Zhang X
Keyword(s):  
Growth Medium ◽  
Statistical Approach ◽  
Antibiotic Activity ◽  
Xenorhabdus Nematophila ◽  
Fermentation Conditions

scholarly journals Increasing the Production of Xenocoumacin 1 by Optimizing the Fermentation Process of Xenorhabdus Nematophila

2021 ◽  
Author(s):  
Yunfei Han ◽  
Jiangtao Gao ◽  
Shujing Zhang ◽  
Jinhua Han ◽  
Zhiqiang Yan ◽  
...  
Keyword(s):  
Fermentation Process ◽  
Inoculum Size ◽  
Water Soluble ◽  
Liquid Volume ◽  
Agitation Rate ◽  
Xenorhabdus Nematophila ◽  
Fermentation Conditions ◽  
Medium Components ◽  
Proteose Peptone ◽  
Initial Ph

Abstract Background: Xenocoumacin 1 (Xcn 1), a kind of water-soluble antibiotic discovered from the cell-free broth of Xenorhabdus nematophila YL001, has exhibited excellent activity against bacteria, oomycetes and fungi. However, the low yield limits the development and utilization of Xcn1. In order to increase the yield of Xcn1, the fermentation process was optimized in this study. Results: Maltose and proteose peptone were identified as the best carbon and nitrogen sources that significantly affected Xcn1 production using a-factor-at-a-time approach. Response surface methodology was applied to optimize the medium constituents for Xcn1 production by X. nematophila YL001. Higher Xcn1-content (113.65 μg/mL) was obtained after optimizing medium components. The optimal levels of medium components were (g/L): proteose peptone 20.83, maltose 12.74, K2HPO4 3.77. Fermentation conditions, such as initial pH, inoculum size, temperature, rotation speed, liquid volume and the length of fermentation, were also investigated by using a-factor-at-a-time method to get a higher production of Xcn1. X. nematophila YL001 was able to produce higher Xcn1 (153.56 μg/mL) at 25°C, initial pH 7.0, inoculum size 10%, culture medium 75 mL in a 250 mL shake flash with an agitation rate of 150 rpm for 48h. Additionally, kinds, concentrations and adding time of the precursor were also investigated. X. nematophila YL001 was able to produce the highest Xcn1 (173.99 μg/mL) when the arginine was added to the broth with 3 mmol/L at the 12th hour. An overall 243.38% increase in Xcn1 content was obtained as compared with mean observed response at TSB medium.Conclusions: To the best of our knowledge, there are no reports on optimization of fermentation process for Xcn1 production quantified by HPLC. The results show that nutrition, precursors and fermentation conditions had a highly influence on the production of Xcn1 by X. nematophila YL001. The optimized medium and fermentation conditions resulted in a 243.38% increase in Xcn1 production. This work will be helpful for the development of X. nematophila YL001 cultivation process for efficient Xcn1 production and lay a foundation for its industrial production.

scholarly journals Manipulation of pH Shift to Enhance the Growth and Antibiotic Activity ofXenorhabdus nematophila

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Yonghong Wang ◽  
Xiangling Fang ◽  
Yongpeng Cheng ◽  
Xing Zhang
Keyword(s):  
Cell Growth ◽  
Control Strategy ◽  
Antibiotic Production ◽  
Ph Control ◽  
Antibiotic Activity ◽  
Ph Effects ◽  
Xenorhabdus Nematophila ◽  
Ph Shift ◽  
Constant Ph ◽  
Initial Ph

To evaluate the effects of pH control strategy on cell growth and the production of antibiotic (cyclo(2-Me-BABA-Gly)) byXenorhabdus nematophilaand enhance the antibiotic activity. The effects of uncontrolled- (different initial pH) and controlled-pH (different constant pH and pH-shift) operations on cell growth and antibiotic activity ofX. nematophilaYL00I were examined. Experiments showed that the optimal initial pH for cell growth and antibiotic production ofX. nematophilaYL001 occurred at 7.0. Under different constant pH, a pH level of 7.5 was found to be optimal for biomass and antibiotic activity at 23.71 g/L and 100.0 U/mL, respectively. Based on the kinetic information relating to the different constant pH effects on the fermentation ofX. nematophilaYL001, a two-stage pH control strategy in which pH 6.5 was maintained for the first 24 h, and then switched to 7.5 after 24 h, was established to improve biomass production and antibiotic activity. By applying this pH-shift strategy, the maximal antibiotic activity and productivity were significantly improved and reaching 185.0 U/mL and 4.41 U/mL/h, respectively, compared to values obtained from constant pH operation (100.0 U/mL and 1.39 U/mL/h).

Enhanced antibiotic activity of Xenorhabdus nematophila by medium optimization

2008 ◽  
Vol 99 (6) ◽  
pp. 1708-1715 ◽  
Author(s):  
Yong-Hong Wang ◽  
Yu-Ping Li ◽  
Qiang Zhang ◽  
Xing Zhang
Keyword(s):  
Medium Optimization ◽  
Antibiotic Activity ◽  
Xenorhabdus Nematophila

Ultrastructural Alterations in Hela Cells Induced by Spider Venom

1967 ◽  
Vol 25 ◽  
pp. 20-21
Author(s):  
Dale E. McClendon ◽  
Paul N. Morgan ◽  
Bernard L. Soloff
Keyword(s):  
Growth Medium ◽  
Mammalian Cells ◽  
Carcinoma Cells ◽  
Venom Protein ◽  
Sterile Saline ◽  
Carbon Coated ◽  
Available Information ◽  
Loxosceles Reclusa ◽  
Essential Growth ◽  
Solution Cultures

It has been observed that minute amounts of venom from the brown recluse spider, Loxosceles reclusa, are capable of producing cytotoxic changes in cultures of certain mammalian cells (Morgan and Felton, 1965). Since there is little available information concerning the effect of venoms on susceptible cells, we have attempted to characterize, at the electron microscope level, the cytotoxic changes produced by the venom of this spider.Cultures of human epithelial carcinoma cells, strain HeLa, were initiated on sterile, carbon coated coverslips contained in Leighton tubes. Each culture was seeded with approximately 1x105 cells contained in 1.5 ml of a modified Eagle's minimum essential growth medium prepared in Hank's balanced salt solution. Cultures were incubated at 36° C. for three days prior to the addition of venom. The venom was collected from female brown recluse spiders and diluted in sterile saline. Protein determinations on the venom-were made according to the spectrophotometric method of Waddell (1956). Approximately 10 μg venom protein per ml of fresh medium was added to each culture after discarding the old growth medium. Control cultures were treated similarly, except that no venom was added. All cultures were reincubated at 36° C.

Effect of Iron Limitation on the Ultrastructure of Agmenellum Quadruplicatum

1981 ◽  
Vol 39 ◽  
pp. 410-411
Author(s):  
L. P. Hardie ◽  
D. L. Balkwill ◽  
S. E. Stevens
Keyword(s):  
Growth Medium ◽  
Green Alga ◽  
Natural Habitat ◽  
Iron Limitation ◽  
Natural Environments ◽  
Blue Green Alga ◽  
Marine Cyanobacterium ◽  
Natural Systems ◽  
Thin Sectioning ◽  
Agmenellum Quadruplicatum

Agmenellum quadruplicatum is a unicellular, non-nitrogen-fixing, marine cyanobacterium (blue-green alga). The ultrastructure of this organism, when grown in the laboratory with all necessary nutrients, has been characterized thoroughly. In contrast, little is known of its ultrastructure in the specific nutrient-limiting conditions typical of its natural habitat. Iron is one of the nutrients likely to limit this organism in such natural environments. It is also of great importance metabolically, being required for both photosynthesis and assimilation of nitrate. The purpose of this study was to assess the effects (if any) of iron limitation on the ultrastructure of A. quadruplicatum. It was part of a broader endeavor to elucidate the ultrastructure of cyanobacteria in natural systemsActively growing cells were placed in a growth medium containing 1% of its usual iron. The cultures were then sampled periodically for 10 days and prepared for thin sectioning TEM to assess the effects of iron limitation.

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