Effect of duration of osmotic downshock and coexisting glutamate on survival and uptake of ectoine in halotolerant Brevibacterium sp. JCM 6894

2006 ◽  
Vol 101 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Shinichi Nagata ◽  
Chenxiang Wang
Keyword(s):  
Osmotic Downshock

Effect of osmotic downshock treatment on the yield of ectione synthesized by Halomonas sp. EG6

2008 ◽  
Vol 136 ◽  
pp. S541
Author(s):  
Omneya Osman ◽  
Shoko Tanabe-Hosoi ◽  
Schinichi Nagata
Keyword(s):  
Osmotic Downshock

Study on Pure Aqueous Extraction Method of PHB/Ectoine Co-Products Based on Osmotic Downshock

2014 ◽  
Vol 955-959 ◽  
pp. 3377-3380 ◽  
Author(s):  
Qing Chen ◽  
Te Wang ◽  
Jin Dan Zhao ◽  
Fu Hui Kang ◽  
Yi Ming Zhang ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Hollow Fiber ◽  
Extraction Method ◽  
Pure Water ◽  
Aqueous Extraction ◽  
Extraction Rate ◽  
Extraction Temperature ◽  
Optimal Conditions ◽  
Pressure Extraction ◽  
Osmotic Downshock

The simultaneously co-production of Poly-β-hydroxybutyrate (PHB) and ectoine in a process (PHB/Ect co-production) and co-products extraction have great significant for reducing the manufacture cost and promoting industrialization of PHB and ectoine. The pure aqueous extraction method based on osmotic downshock was used for the extraction of PHB/Ect co-products byH. salina. The effects of osmotic pressure, extraction temperature and extraction time on the extraction rate of PHB were investigated. The ectoine was extracted and purified by the techniques of hollow fiber and ion exchange. The optimal conditions for PHB extraction were osmotic downshock in pure water, extraction temperature at 60 °C and extraction for 4 h. The extraction rate of PHB was 87.5%. The extraction rate of ectoine was 84.2%.

Uptake and utilization of ectoine by halotolerant Brevibacterium sp. JCM 6894 subjected to osmotic downshock

2002 ◽  
Vol 94 (5) ◽  
pp. 440-446 ◽  
Author(s):  
Yao Bing Wang ◽  
Tomohiko Ikeuchi ◽  
Yi Jin ◽  
Shinichi Nagata
Keyword(s):  
Osmotic Downshock

Uptake and Utilization of Ectoine by Halotolerant Brevibacterium sp. JCM 6894 Subjected to Osmotic Downshock.

2002 ◽  
Vol 94 (5) ◽  
pp. 440-446
Author(s):  
YAO BING WANG ◽  
TOMOHIKO IKEUCHI ◽  
YI JIN ◽  
SHINICHI NAGATA
Keyword(s):  
Osmotic Downshock

scholarly journals A Single Mechanosensitive Channel ProtectsFrancisella tularensissubsp.holarcticafrom Hypoosmotic Shock and Promotes Survival in the Aquatic Environment

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
David R. Williamson ◽  
Kalyan K. Dewan ◽  
Tanmay Patel ◽  
Catherine M. Wastella ◽  
Gang Ning ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Francisella Tularensis ◽  
Mechanosensitive Channel ◽  
Mammalian Host ◽  
Average Cell Size ◽  
Average Cell ◽  
Content Type ◽  
Hypoosmotic Shock ◽  
Osmotic Downshock

ABSTRACTFrancisella tularensissubsp.holarcticais found in North America and much of Europe and causes the disease tularemia in humans and animals. An aquatic cycle has been described for this subspecies, which has caused waterborne outbreaks of tularemia in at least 10 countries. In this study, we sought to identify the mechanosensitive channel(s) required for the bacterium to survive the transition from mammalian hosts to freshwater, which is likely essential for the transmission of the bacterium between susceptible hosts. A single 165-amino-acid MscS-type mechanosensitive channel (FtMscS) was found to protectF. tularensissubsp.holarcticafrom hypoosmotic shock, despite lacking much of the cytoplasmic vestibule domain found in well-characterized MscS proteins from other organisms. The deletion of this channel did not affect virulence within the mammalian host; however,FtMscS was required to survive the transition from the host niche to freshwater. The deletion ofFtMscS did not alter the sensitivity ofF. tularensissubsp.holarcticato detergents, H2O2, or antibiotics, suggesting that the role ofFtMscS is specific to protection from hypoosmotic shock. The deletion ofFtMscS also led to a reduced average cell size without altering gross cell morphology. The mechanosensitive channel identified and characterized in this study likely contributes to the transmission of tularemia between hosts by allowing the bacterium to survive the transition from mammalian hosts to freshwater.IMPORTANCEThe contamination of freshwater byFrancisella tularensissubsp.holarcticahas resulted in a number of outbreaks of tularemia. Invariably, the contamination originates from the carcasses or excreta of infected animals and thus involves an abrupt osmotic downshock as the bacteria enter freshwater. HowF. tularensissurvives this drastic change in osmolarity has not been clear, but here we report that a single mechanosensitive channel protects the bacterium from osmotic downshock. This channel is functional despite lacking much of the cytoplasmic vestibule domain that is present in better-studied organisms such asEscherichia coli; this report builds on previous studies that have suggested that parts of this domain are dispensable for downshock protection. These findings extend our understanding of the aquatic cycle and ecological persistence ofF. tularensis, with further implications for mechanosensitive channel biology.

Study on Synthesis of PHB by Moderate Halophile and Aqueous Extraction of PHB

2013 ◽  
Vol 448-453 ◽  
pp. 160-163
Author(s):  
Qing Chen ◽  
Ling Hua Zhang
Keyword(s):  
Extraction Efficiency ◽  
Rate Increase ◽  
Sodium Dodecyl ◽  
Halophilic Bacterium ◽  
Aqueous Extraction ◽  
Extraction Rate ◽  
Moderate Halophile ◽  
Extraction And Purification ◽  
Nacl Concentration ◽  
Osmotic Downshock

PHB (Poly-β-hydroxybutyrate) has been widely in the areas of industrial packaging, pharmacy and agriculture. Currently, its production cost, especially in extraction and purification are high. A moderate halophilic bacterium was used for PHB synthesis and an aqueous extraction method based on osmotic downshock was investigated in this paper to further improve the extraction efficiency. PHB synthesised by moderate halophile with certain NaCl concentration can be released with cell lysis by osmotic downshock. Meanwhile the high temperature, ultrasonic and SDS (Sodium dodecyl sulfate) can enhance the release. After 48 h of fermentation, the production of PHB by Halomonas salina was 6.5 g/L. The extraction rate of PHB was 24.6% with osmotic downshock and 35.4% with additional ultrasonic assistance at 65 °C. A further addition of 0.5% SDS made the extraction rate increase to 75.4%. Thereinto, the addition of 6% NaCl had significantly improved the aqueous extraction rate to 92.3%.

scholarly journals Efficient cyclic system to yield ectoine usingBrevibacterium sp. JCM 6894 subjected to osmotic downshock

2008 ◽  
Vol 99 (4) ◽  
pp. 941-948 ◽  
Author(s):  
Shinichi Nagata ◽  
Yaoqiang Wang ◽  
Akinobu Oshima ◽  
Linghua Zhang ◽  
Hideyoshi Miyake ◽  
...  
Keyword(s):  
Cyclic System ◽  
Osmotic Downshock
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