Methods to optimize the production of gamma-aminobutyric acid （GABA） by Lactobacillus brevis CGMCC 1306 were investigated. Results indicated that cell growth was maximal at pH 5.0, while pH 4.5 was pref-erable to GA...Methods to optimize the production of gamma-aminobutyric acid （GABA） by Lactobacillus brevis CGMCC 1306 were investigated. Results indicated that cell growth was maximal at pH 5.0, while pH 4.5 was pref-erable to GABA formation. The optimal temperature for cell growth （35 °C） was lower than that for GABA forma-tion （40 °C）. In a two-stage pH and temperature control fermentation, cultures were maintained at pH 5.0 and 35 °C for 32 h, then adjusted to pH 4.5 and 40 °C, GABA production increased remarkably and reached 474.79 mmol·L-1 at 72 h, while it was 398.63 mmol·L-1 with one stage pH and temperature control process, in which cultivation con-ditions were constantly controlled at pH 5.0 and 35 °C. In order to avoid the inhibition of cell growth at higher L-monosodium glutamate （L-MSG） concentrations, the two-stage control fermentation with substrate feeding strat-egy was applied to GABA production, with 106.87 mmol （20 g） L-MSG supplemented into the shaking-flask at 32 h and 56 h post-inoculation separately. The GABA concentration reached 526.33 mmol·L-1 at 72 h with the fer-mentation volume increased by 38%. These results will provide primary data to realize large-scale production of GABA by L. brevis CGMCC 1306.展开更多
[Objective] The paper was to study the growth and development of Onychostoma sima in postembryonic development stage. [Method] The oosperm was obtained by artificial spawning and artificial insemination method, and ha...[Objective] The paper was to study the growth and development of Onychostoma sima in postembryonic development stage. [Method] The oosperm was obtained by artificial spawning and artificial insemination method, and hatched under laboratory condition. The indexes such as body weight, body length, length in front of anus and body height were measured to establish larvae growth model. [Result] When the water temperature was （20±1.5） ℃, the body length and body weight of newly hatched larvae were （10.28±0.05） mm and （7.79±0.08） mg, respectively. O. sima larvae begin to feed on the 4 th day after hatching, the initial feeding rate was 48%, the highest feeding rate was 100% on the 6 th d. The-point-of-no-return （PNR） was 13.5 d. In addition, it was also observed that the appearance time of PNR point of O. sima larvae was close to death time of completely starved group, being only 2 d, indicating that once O. sima larvae reached the PNR point, they would face death threats within short time. Therefore, various growth conditions for O. sima larvae should be satisfied to ensure full development of all organs, thereby reducing death and growth stagnation caused by adverse environment in early postembryonic stage. [Conclusion] The study provided theoretical basis for solving the problems in artificial breeding.展开更多
Blaptostethus pallescens Poppius (Heteroptera:Anthocoridae),which is amenable to mass rearing,has proved to be a potential predator of sucking pests like mites and thrips.Recently,the cotton mealybug Phenacoccus solen...Blaptostethus pallescens Poppius (Heteroptera:Anthocoridae),which is amenable to mass rearing,has proved to be a potential predator of sucking pests like mites and thrips.Recently,the cotton mealybug Phenacoccus solenopsis Tinsley emerged as a serious pest on cotton in India.Laboratory studies indicated that B.pallescens could feed on the cotton mealybug.Hence,further investigations were conducted to understand the stage of the predator which is most potential and the pest stage preferred by the predator.Mature nymphs and adults of B.pallescens could predate equally well on the neonates of cotton mealybug.Young (three to four-day-old) nymphs of the predator could not feed on any stage of the cotton mealybug.Mature nymphs (seven-day-old and above) and adults could effectively predate on both young and mature cotton mealybug crawlers,though preference was more for the younger crawlers.However,nymphs and adults of B.pallescens could not predate on the adult stage of the mealybug.Different predator:pest ratios were tested in cage studies and it emerged that B.pallescens adults released against the mealybug crawlers at a ratio of 1:5 and nymphal release at 1:10 caused maximum mortality of the mealybug crawlers.Considering the fast multiplication rate of cotton mealybug and the large number of predators which have to be released to manage them,further detailed studies are necessary on utilizing B.pallescens to target the neonates and younger stages of the cotton mealybug in field conditions.展开更多
基金Supported by the National＇Naturai Science Foundation of China （30970638, 21176220 and 31240054）, Zhejiang Provincial Natural Science Foundation （Z13B06008） and the National Basic Research Program of China （2007CB714305）.
文摘Methods to optimize the production of gamma-aminobutyric acid （GABA） by Lactobacillus brevis CGMCC 1306 were investigated. Results indicated that cell growth was maximal at pH 5.0, while pH 4.5 was pref-erable to GABA formation. The optimal temperature for cell growth （35 °C） was lower than that for GABA forma-tion （40 °C）. In a two-stage pH and temperature control fermentation, cultures were maintained at pH 5.0 and 35 °C for 32 h, then adjusted to pH 4.5 and 40 °C, GABA production increased remarkably and reached 474.79 mmol·L-1 at 72 h, while it was 398.63 mmol·L-1 with one stage pH and temperature control process, in which cultivation con-ditions were constantly controlled at pH 5.0 and 35 °C. In order to avoid the inhibition of cell growth at higher L-monosodium glutamate （L-MSG） concentrations, the two-stage control fermentation with substrate feeding strat-egy was applied to GABA production, with 106.87 mmol （20 g） L-MSG supplemented into the shaking-flask at 32 h and 56 h post-inoculation separately. The GABA concentration reached 526.33 mmol·L-1 at 72 h with the fer-mentation volume increased by 38%. These results will provide primary data to realize large-scale production of GABA by L. brevis CGMCC 1306.
基金Supported by Special Funds for Breeding Research of Sichuan Provincial Department of Finance(2006YZGG08-002)~~
文摘[Objective] The paper was to study the growth and development of Onychostoma sima in postembryonic development stage. [Method] The oosperm was obtained by artificial spawning and artificial insemination method, and hatched under laboratory condition. The indexes such as body weight, body length, length in front of anus and body height were measured to establish larvae growth model. [Result] When the water temperature was （20±1.5） ℃, the body length and body weight of newly hatched larvae were （10.28±0.05） mm and （7.79±0.08） mg, respectively. O. sima larvae begin to feed on the 4 th day after hatching, the initial feeding rate was 48%, the highest feeding rate was 100% on the 6 th d. The-point-of-no-return （PNR） was 13.5 d. In addition, it was also observed that the appearance time of PNR point of O. sima larvae was close to death time of completely starved group, being only 2 d, indicating that once O. sima larvae reached the PNR point, they would face death threats within short time. Therefore, various growth conditions for O. sima larvae should be satisfied to ensure full development of all organs, thereby reducing death and growth stagnation caused by adverse environment in early postembryonic stage. [Conclusion] The study provided theoretical basis for solving the problems in artificial breeding.
基金financial support extended by the Cotton Mission Mode project TMC MM1 3. 3
文摘Blaptostethus pallescens Poppius (Heteroptera:Anthocoridae),which is amenable to mass rearing,has proved to be a potential predator of sucking pests like mites and thrips.Recently,the cotton mealybug Phenacoccus solenopsis Tinsley emerged as a serious pest on cotton in India.Laboratory studies indicated that B.pallescens could feed on the cotton mealybug.Hence,further investigations were conducted to understand the stage of the predator which is most potential and the pest stage preferred by the predator.Mature nymphs and adults of B.pallescens could predate equally well on the neonates of cotton mealybug.Young (three to four-day-old) nymphs of the predator could not feed on any stage of the cotton mealybug.Mature nymphs (seven-day-old and above) and adults could effectively predate on both young and mature cotton mealybug crawlers,though preference was more for the younger crawlers.However,nymphs and adults of B.pallescens could not predate on the adult stage of the mealybug.Different predator:pest ratios were tested in cage studies and it emerged that B.pallescens adults released against the mealybug crawlers at a ratio of 1:5 and nymphal release at 1:10 caused maximum mortality of the mealybug crawlers.Considering the fast multiplication rate of cotton mealybug and the large number of predators which have to be released to manage them,further detailed studies are necessary on utilizing B.pallescens to target the neonates and younger stages of the cotton mealybug in field conditions.
