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91.
Meng-Yao Li Bruno Ebel Fabrice Blanchard Cédric Paris Emmanuel Guedon Annie Marc 《Biotechnology and bioengineering》2019,116(5):985-993
The cell-specific growth rate (µ) is a critical process parameter for antibody production processes performed by animal cell cultures, as it describes the cell growth and reflects the cell physiological state. When there are changes in these parameters, which are indicated by variations of µ, the synthesis and the quality of antibodies are often affected. Therefore, it is essential to monitor and control the variations of µto assure the antibody production and achieve high product quality. In this study, a novel approach for on-line estimation of µ was developed based on the process analytical technology initiative by using an in situ dielectric spectroscopy. Critical moments, such as significant µ decreases, were successfully detected by this method, in association with changes in cell physiology as well as with an accumulation of nonglycosylated antibodies. Thus, this method was used to perform medium renewals at the appropriate time points, maintaining the values of µ close to its maximum. Using this method, we demonstrated that the physiological state of cells remained stable, the quantity and the glycosylation quality of antibodies were assured at the same time, leading to better process performances compared with the reference feed-harvest cell cultures carried out by using off-line nutrient measurements. 相似文献
92.
Photoautotrophic organisms are promising hosts for biocatalytic oxyfunctionalizations because they supply reduction equivalents as well as O2 via photosynthetic water oxidation. Thus far, research on photosynthesis-driven bioprocesses mainly focuses on strain development and the proof of principle in small-scale biocatalytic reaction setups. This study investigates the long-term applicability of the previously developed cyanobacterial strain Synechocystis sp. PCC 6803_BGT harboring the alkane monooxygenase system AlkBGT catalyzing terminal alkyl group oxyfunctionalization. For the regiospecific ω-hydroxylation of nonanoic acid methyl ester (NAME), this biocatalyst showed light intensity-independent hydroxylation activity and substantial hydrolysis of NAME to nonanoic acid. Substrate mass transfer limitation, substrate hydrolysis, as well as reactant toxicity were overcome via in situ substrate supply by means of a two-liquid phase system. The application of diisononyl phthalate as organic carrier solvent enabled 1.7-fold increased initial specific activities (5.6 ± 0.1 U/gCDW) and 7.6-fold increased specific yields on biomass (3.8 ± 0.1 mmolH-NAME/gCDW) as compared with single aqueous phase biotransformations. Finally, the whole-cell biotransformation system was successfully scaled from glass tubes to a stirred-tank photobioreactor. This is the first study reporting the application of the two-liquid phase concept for efficient phototrophic whole-cell biocatalysis. 相似文献
93.
94.
Dominiek Vangansbeke Duc Tung Nguyen Joachim Audenaert Ruth Verhoeven Bruno Gobin Luc Tirry Patrick De Clercq 《BioControl》2015,60(5):595-603
The consumption rate of an ectothermic predator is highly temperature-dependent and is a key driver of pest-predator population interactions. Not only average daily temperature, but also diurnal temperature variations may affect prey consumption and life history traits of ectotherms. In the present study, we evaluated the impact of temperature alternations on body size, predation capacity and oviposition rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) when presented with eggs of their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). For both predators, mean daily temperature as well as temperature alternation had a substantial impact on the number of prey consumed. At lower average temperatures, more eggs were killed under an alternating temperature regime (20 °C/5 °C and 25 °C/10 °C) than at the corresponding mean constant temperatures (15 and 20 °C). At higher average temperatures (>25 °C), however, the opposite was observed with higher numbers of prey killed at constant temperatures than at alternating temperatures. At 25 °C, temperature variation had no effect on the predation capacity. A similar trend as for the predation rates was observed for the oviposition rates of the phytoseiids. Body size of N. californicus was affected both by average daily temperature and temperature variation, with smaller adult females emerging at alternating temperatures than at constant temperatures, whereas for P. persimilis, temperature variation had no impact on its body size. Our results demonstrate that temperature variations are likely to affect biological control of T. urticae by the studied phytoseiid predators. 相似文献
95.
Gatts Pedro Franco Marcos dos Santos Luciano Rocha Diogo de Sá Fabrício Netto Eurico Machado Phillipe Masi Bruno Zalmon Ilana 《Aquatic Ecology》2015,49(3):343-355
Aquatic Ecology - To investigate how variations in the small-scale distance between patchy reef modules affect the structure and composition of the associated ichthyofauna, concrete reefballs were... 相似文献
96.
97.
The role of forest structure and human occupation in structuring mammal assemblages in oligotrophic ecosystems of Central Amazonia 下载免费PDF全文
Large mammals are vulnerable to extinction, and respond directly to ecological gradients within the forest and to the intensity of forest product use by humans. In this study, we evaluated the effects of differences in forest structure and human occupation history on the composition of medium and large‐sized mammal assemblages of the terra‐firme forests of the Anavilhanas National Park, one of the most oligotrophic Amazonian ecosystems. Mammal surveys were conducted along 11 linear transects of 4 km, six of which were located in areas once inhabited by people and managed until the year that the park was created (over 30 years ago), and five in areas that were not inhabited at that time. We detected 469 individuals of 26 species during diurnal and nocturnal sampling, and 11 additional species outside transects. Human occupation history was strongly related to forest structure components. Fruit biomass, canopy cover and tree size were strongly associated with uninhabited areas, and influenced the structure of mammal assemblages. A direct relationship between diet category and species size was observed. Large frugivore‐herbivores and carnivores were more closely associated with areas with more fruit, larger trees and greater canopy cover. In contrast, small arboreal frugivore‐omnivores associated more closely with open canopy and smaller trees. Our study indicated that the effects of human occupation history on forest structure are still evident three decades after the removal of local people from the park. This long‐term effect can be explained by the low resilience of the Anavilhanas environments, demonstrating the fragility of mammal assemblages in face of anthropogenic variation in forest structure in the oligotrophic ecosystems of the Negro River basin. 相似文献
98.
Carrie V. Kappel Carlos M. Duarte Keith Brander Christopher J. Brown John F. Bruno Lauren Buckley Michael T. Burrows Benjamin S. Halpern Wolfgang Kiessling Pippa Moore John M. Pandolfi Camille Parmesan Elvira S. Poloczanska David S. Schoeman William J. Sydeman Anthony J. Richardson 《Global Ecology and Biogeography》2015,24(1):64-76
99.
Thomas?Durand Sophie?Jacob Laura?Lebouil Hassen?Douzane Philippe?Lestaevel Amithys?Rahimian Dimitri?Psimaras Lo?c?Feuvret Delphine?Leclercq Bruno?Brochet Radia?Tamarat Fabien?Milliat Marc?Benderitter Nicolas?Vayatis Georges?No?l Khê?Hoang-Xuan Jean-Yves?Delattre Damien?Ricard Marie-Odile?BernierEmail author 《BMC neurology》2015,15(1):261
Background
Radiotherapy is one of the most important treatments of primary and metastatic brain tumors. Unfortunately, it can involve moderate to severe complications among which leukoencephalopathy is very frequent and implies cognitive deficits such as memory, attention and executive dysfunctions. However, the incidence of this complication is not well established and the risk factors and process are poorly understood. The main objective of the study is to improve knowledge on radio-induced leukoencephalopathy based on pluridisciplinar approaches combining cognitive, biologic, imagery and dosimetric investigations.Method/Design
The EpiBrainRad study is a prospective cohort study including newly diagnosed high grade gliomas patients treated by radiotherapy and concomitant-adjuvant temozolomide chemotherapy. Patients are included between their surgery and first day of radio-chemotherapy, and the follow-up lasts for 3 years after treatment. Cognitive functioning assessments, specific blood biomarkers measures and magnetic resonance imagery are performed at different moment during the follow-up, and a specific dosimetric assessment of organs involved in the beam fields is performed. Firstly, leukoencephalopathy incidence rate will be estimated in this population. Secondly, correlations between cognitive impairments and dosimetry, biomarkers ranges and anomalies on imagery will be analyzed in order to better understand the onset and evolution of cognitive decrement associated with radiotherapy. Furthermore, a new cognitive test, quickly and easily performed, will be studied to determine its sensibility to detect leukoencephalopathy decrement.Discussion
With an original multidisciplinary approach, the EpiBrainRad study aims to improve knowledge on radio-induced leukoencephalopathy in order to improve its early diagnosis and prevention. The main challenge is to preserve quality-of-life after cancer treatments which imply to study the incidence of radiation-induced complications and their associated risk factors.Trial Registration
NCT02544178100.
Clément Palpacuer Bruno Laviolle Rémy Boussageon Jean Michel Reymann Eric Bellissant Florian Naudet 《PLoS medicine》2015,12(12)