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P. R. Patnaik - One of the best experts on this subject based on the ideXlab platform.

  • A simulation study of dynamic neural filtering and control of a fed-batch bioreactor under nonideal conditions ☆
    Chemical Engineering Journal, 2001
    Co-Authors: P. R. Patnaik
    Abstract:

    Bioreactors utilizing Genetically Modified Bacteria under realistic conditions are difficult to monitor and model because of imperfect mixing, disturbances and uncertain kinetics. In this work, neural filtering and control have been applied to such a nonideal fed-batch bioreactor containing recombinant Escherichia coli to produce β-galactosidase. Data simulating industrial fermentation were generated by introducing incomplete mixing in the broth and Gaussian noise in the feed stream. Based on a previous study, an Elman neural network was employed to represent the simulated data. To this, an autoassociative network was added in order to filter the noise and a feed forward network to control the fermentation. Performance of the fermentation with this system of three neural networks optimized together has been shown to be superior to sequential optimization, neural control without filtering, PID control with filtering, and also a noise-free fermentation. Thus, a suitably designed system of neural networks provides rapid on-line estimations and improves bioreactor performance under conditions simulating industrial fermentation.

  • A simulation study of dynamic neural filtering and control of a fed-batch bioreactor under nonideal conditions
    Chemical Engineering Journal, 2001
    Co-Authors: P. R. Patnaik
    Abstract:

    Bioreactors utilizing Genetically Modified Bacteria under realistic conditions are difficult to monitor and model because of imperfect mixing, disturbances and uncertain kinetics. In this work, neural filtering and control have been applied to such a nonideal fed-batch bioreactor containing recombinant Escherichia coli to produce β-galactosidase. Data simulating industrial fermentation were generated by introducing incomplete mixing in the broth and Gaussian noise in the feed stream. Based on a previous study, an Elman neural network was employed to represent the simulated data. To this, an autoassociative network was added in order to filter the noise and a feed forward network to control the fermentation. Performance of the fermentation with this system of three neural networks optimized together has been shown to be superior to sequential optimization, neural control without filtering, PID control with filtering, and also a noise-free fermentation. Thus, a suitably designed system of neural networks provides rapid on-line estimations and improves bioreactor performance under conditions simulating industrial fermentation. © 2001 Elsevier Science B.V. All rights reserved.

Ibrahima Faye - One of the best experts on this subject based on the ideXlab platform.

  • Transstadial and horizontal transfer of Bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to Bacteria-containing water
    Acta Tropica, 2008
    Co-Authors: J. M. Lindh, Anna-karin Borg-karlson, Ibrahima Faye
    Abstract:

    In a paratransgenic approach, Genetically Modified Bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic Bacteria ...

  • Transstadial and horizontal transfer of Bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to Bacteria-containing water
    Acta Tropica, 2008
    Co-Authors: J. M. Lindh, Anna-karin Borg-karlson, Ibrahima Faye
    Abstract:

    In a paratransgenic approach, Genetically Modified Bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic Bacteria can be introduced and then kept in a mosquito population. Here, we investigated transstadial and horizontal transfer of Bacteria within an Anopheles gambiae mosquito colony with the focus on spiked breeding sites as a possible means of introducing Bacteria to mosquitoes. A Pantoea stewartii strain, previously isolated from An. gambiae, marked with a green fluorescent protein (GFP), was introduced to mosquitoes in different life stages. The following life stages or older mosquitoes in the case of adults were screened for Bacteria in their guts. In addition to P. stewartii other Bacteria were isolated from the guts: these were identified by 16S rRNA sequence analysis and temporal temperature gradient gel electrophoresis (TTGE). Bacteria were transferred from larvae to pupae but not from pupae to adults. The mosquitoes were able to take up Bacteria from the water they emerged from and transfer the same Bacteria to the water they laid eggs in. Elizabethkingia meningoseptica was more often isolated from adult mosquitoes than P. stewartii. A bioassay was used to examine An. gambiae oviposition responses towards Bacteria-containing solutions. The volatiles emitted from the solutions were sampled by headspace-solid phase microextraction (SPME) and identified by gas chromatography and mass spectrometry (GC-MS) analysis. P. stewartii but not E. meningoseptica mediated a positive oviposition response. The volatiles emitted by P. stewartii include indole and 3-methyl-1-butanol, which previously have been shown to affect An. gambiae mosquito behaviour. E. meningoseptica emitted indole but not 3-methyl-1-butanol, when suspended in saline. Taken together, this indicates that it may be possible to create attractive breeding sites for distribution of Genetically Modified Bacteria in the field in a paratransgenic approach against malaria. Further research is needed to determine if the Bacteria are also transferred in the same way in nature. © 2008.

Simon R Carding - One of the best experts on this subject based on the ideXlab platform.

  • use of Genetically Modified Bacteria for drug delivery in humans revisiting the safety aspect
    Scientific Reports, 2017
    Co-Authors: Udo Wegmann, Ana L Carvalho, Martin Stocks, Simon R Carding
    Abstract:

    The use of live, Genetically Modified Bacteria as delivery vehicles for biologics is of considerable interest scientifically and has attracted significant commercial investment. We have pioneered the use of the commensal gut bacterium Bacteroides ovatus for the oral delivery of therapeutics to the gastrointestinal tract. Here we report on our investigations of the biological safety of engineered B. ovatus Bacteria that includes the use of thymineless death as a containment strategy and the potential for the spread of transgenes in vivo in the mammalian gastrointestinal tract. We demonstrate the ability of GM-strains of Bacteroides to survive thymine starvation and overcome it through the exchange of genetic material. We also provide evidence for horizontal gene transfer in the mammalian gastrointestinal tract resulting in transgene-carrying wild type Bacteria. These findings sound a strong note of caution on the employment of live Genetically Modified Bacteria for the delivery of biologics.

J. M. Lindh - One of the best experts on this subject based on the ideXlab platform.

  • Transstadial and horizontal transfer of Bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to Bacteria-containing water
    Acta Tropica, 2008
    Co-Authors: J. M. Lindh, Anna-karin Borg-karlson, Ibrahima Faye
    Abstract:

    In a paratransgenic approach, Genetically Modified Bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic Bacteria ...

  • Transstadial and horizontal transfer of Bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to Bacteria-containing water
    Acta Tropica, 2008
    Co-Authors: J. M. Lindh, Anna-karin Borg-karlson, Ibrahima Faye
    Abstract:

    In a paratransgenic approach, Genetically Modified Bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic Bacteria can be introduced and then kept in a mosquito population. Here, we investigated transstadial and horizontal transfer of Bacteria within an Anopheles gambiae mosquito colony with the focus on spiked breeding sites as a possible means of introducing Bacteria to mosquitoes. A Pantoea stewartii strain, previously isolated from An. gambiae, marked with a green fluorescent protein (GFP), was introduced to mosquitoes in different life stages. The following life stages or older mosquitoes in the case of adults were screened for Bacteria in their guts. In addition to P. stewartii other Bacteria were isolated from the guts: these were identified by 16S rRNA sequence analysis and temporal temperature gradient gel electrophoresis (TTGE). Bacteria were transferred from larvae to pupae but not from pupae to adults. The mosquitoes were able to take up Bacteria from the water they emerged from and transfer the same Bacteria to the water they laid eggs in. Elizabethkingia meningoseptica was more often isolated from adult mosquitoes than P. stewartii. A bioassay was used to examine An. gambiae oviposition responses towards Bacteria-containing solutions. The volatiles emitted from the solutions were sampled by headspace-solid phase microextraction (SPME) and identified by gas chromatography and mass spectrometry (GC-MS) analysis. P. stewartii but not E. meningoseptica mediated a positive oviposition response. The volatiles emitted by P. stewartii include indole and 3-methyl-1-butanol, which previously have been shown to affect An. gambiae mosquito behaviour. E. meningoseptica emitted indole but not 3-methyl-1-butanol, when suspended in saline. Taken together, this indicates that it may be possible to create attractive breeding sites for distribution of Genetically Modified Bacteria in the field in a paratransgenic approach against malaria. Further research is needed to determine if the Bacteria are also transferred in the same way in nature. © 2008.

Anna-karin Borg-karlson - One of the best experts on this subject based on the ideXlab platform.

  • Transstadial and horizontal transfer of Bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to Bacteria-containing water
    Acta Tropica, 2008
    Co-Authors: J. M. Lindh, Anna-karin Borg-karlson, Ibrahima Faye
    Abstract:

    In a paratransgenic approach, Genetically Modified Bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic Bacteria ...

  • Transstadial and horizontal transfer of Bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to Bacteria-containing water
    Acta Tropica, 2008
    Co-Authors: J. M. Lindh, Anna-karin Borg-karlson, Ibrahima Faye
    Abstract:

    In a paratransgenic approach, Genetically Modified Bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic Bacteria can be introduced and then kept in a mosquito population. Here, we investigated transstadial and horizontal transfer of Bacteria within an Anopheles gambiae mosquito colony with the focus on spiked breeding sites as a possible means of introducing Bacteria to mosquitoes. A Pantoea stewartii strain, previously isolated from An. gambiae, marked with a green fluorescent protein (GFP), was introduced to mosquitoes in different life stages. The following life stages or older mosquitoes in the case of adults were screened for Bacteria in their guts. In addition to P. stewartii other Bacteria were isolated from the guts: these were identified by 16S rRNA sequence analysis and temporal temperature gradient gel electrophoresis (TTGE). Bacteria were transferred from larvae to pupae but not from pupae to adults. The mosquitoes were able to take up Bacteria from the water they emerged from and transfer the same Bacteria to the water they laid eggs in. Elizabethkingia meningoseptica was more often isolated from adult mosquitoes than P. stewartii. A bioassay was used to examine An. gambiae oviposition responses towards Bacteria-containing solutions. The volatiles emitted from the solutions were sampled by headspace-solid phase microextraction (SPME) and identified by gas chromatography and mass spectrometry (GC-MS) analysis. P. stewartii but not E. meningoseptica mediated a positive oviposition response. The volatiles emitted by P. stewartii include indole and 3-methyl-1-butanol, which previously have been shown to affect An. gambiae mosquito behaviour. E. meningoseptica emitted indole but not 3-methyl-1-butanol, when suspended in saline. Taken together, this indicates that it may be possible to create attractive breeding sites for distribution of Genetically Modified Bacteria in the field in a paratransgenic approach against malaria. Further research is needed to determine if the Bacteria are also transferred in the same way in nature. © 2008.