Biopesticides: Feedback from distributors and users

Conference (2011, December)

Biophosphonates for the treatment of osteoporosis

in Osteoporosis : Diagnosis and management (1998)

Biophysical studies support a predicted superhelical structure with armadillo repeats for Ric-8.

in Protein Science : A Publication of the Protein Society (2009), 18(6), 1139-45

Ric-8 is a highly conserved cytosolic protein (MW 63 KDa) initially identified in C. elegans as an essential factor in neurotransmitter release and asymmetric cell division. Two different isoforms have ... [more ▼]

Ric-8 is a highly conserved cytosolic protein (MW 63 KDa) initially identified in C. elegans as an essential factor in neurotransmitter release and asymmetric cell division. Two different isoforms have been described in mammals, Ric-8A and Ric-8B; each possess guanine nucleotide exchange activity (GEF) on heterotrimeric G-proteins, but with different Galpha subunits specificities. To gain insight on the mechanisms involved in Ric-8 cellular functions it is essential to obtain some information about its structure. Therefore, the aim of this work was to create a structural model for Ric-8. In this case, it was not possible to construct a model based on comparison with a template structure because Ric-8 does not present sequence similarity with any other protein. Consequently, different bioinformatics approaches that include protein folding and structure prediction were used. The Ric-8 structural model is composed of 10 armadillo folding motifs, organized in a right-twisted alpha-alpha super helix. In order to validate the structural model, a His-tag fusion construct of Ric-8 was expressed in E. coli, purified by affinity and anion exchange chromatography and subjected to circular dichroism analysis (CD) and thermostability studies. Ric-8 is approximately 80% alpha helix, with a Tm of 43.1 degrees C, consistent with an armadillo-type structure such as alpha-importin, a protein composed of 10 armadillo repeats. The proposed structural model for Ric-8 is intriguing because armadillo proteins are known to interact with multiple partners and participate in diverse cellular functions. These results open the possibility of finding new protein partners for Ric-8 with new cellular functions. [less ▲]

Bioprocédés et biotechnologies

Scientific conference (2010)

Bioprocesses scale-up : Interactions between physico-chemical and biological parameters

Scientific conference (2010, March 15)

Le bioraffinage, une alternative prometteuse à la pétrochimie

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(4), 597-610

Because of the price increase of fossil resources, of their uncertain availability and because of environmental concerns, alternative solutions able to mitigate global warming, and reduce the consumption ... [more ▼]

Because of the price increase of fossil resources, of their uncertain availability and because of environmental concerns, alternative solutions able to mitigate global warming, and reduce the consumption of fossil fuels and carbon dioxide emissions should be promoted. The replacement of petroleum with biomass as raw material for bioenergy (biofuels, power and heat) and chemical production is an interesting option and is the driving force for the development of biorefinery complexes that will have a critical role to play in our common future. A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, heat and chemicals from biomass. In biorefinery, almost all types of biomass feedstocks can be converted to different classes of biofuels and biochemicals through various processes that maximize economic and environmental benefits, while minimizing waste and pollution. Through the integration of green chemistry into biorefineries, and the use of low environmental impact technologies, future sustainable production chains of biofuels and high value chemicals from biomass can therefore be established. Currently, the green biorefinery, the whole-crop biorefinery, the oilseed biorefinery and the lignocellulosic feedstock biorefinery are favoured in research, development and industrial implementation, essentially through fully integrated biorefinery complexes. [less ▲]

Bioreactor hydrodynamic effect on Escherichia coli physiology: experimental results and stochastic simulations.

in Bioprocess and Biosystems Engineering (2005), 28(2), 131-7

A microorganism circulating in a bioreactor can be submitted to hydrodynamic conditions inducing a significant effect on its physiology. The mixing time exhibited by the stirred bioreactor and the ... [more ▼]

A microorganism circulating in a bioreactor can be submitted to hydrodynamic conditions inducing a significant effect on its physiology. The mixing time exhibited by the stirred bioreactor and the circulation of microorganisms are both involved in this reacting system. The mixing component determines the intensity of the concentration gradient and the circulation component determines the way in which the microorganism is exposed to this gradient. These two components linked to the experimental evaluation of microbial physiology can be analysed by a structured stochastic model in the case of a partitioned or "scale-down" reactor (SDR). A stochastic model indeed enables to simulate the mixing process as well as the circulation of microorganisms in SDRs. The superimposition of mixing and circulation processes determines the concentration profile experienced by a microorganism in the reactor. In the present case, the glucose concentration experienced by Escherichia coli has been modelled during a fed-batch culture. In this context, the use of a stochastic hydrodynamic model has permitted to point out an interesting feed pulse retardant effect in the SDRs. Nevertheless, the metabolic response of E. coli is not easy to interpret because of the possible simultaneous developments of overflow metabolism and mixed acid fermentation induced by the strong glucose concentration in the reactor. [less ▲]

BIOREMEDIATION DE SOLS POLLUES AUX HYDROCARBURES – AMELIORATION DE LA BIOREMEDIATION IN SITU DES HYDROCARBURES PAR BIO-AUGMENTATION AU MOYEN DE SOUCHES ENDOGENES ET EXOGENES

Master's dissertation (2010)

This study relates to biological treatment of hydrocarbon polluted soils. Its purpose is to establish an industrial approach of bioaugmentation and to verify its efficiency compared with biostimulation ... [more ▼]

This study relates to biological treatment of hydrocarbon polluted soils. Its purpose is to establish an industrial approach of bioaugmentation and to verify its efficiency compared with biostimulation. The purpose is to simulate in situ bioremediation using experimental columns. It has been demonstrated that it’s possible to produce a biomass able to degrade hydrocarbons in a polluted soil in one month. The main way of hydrocarbon elimination in the soil is biodegradation and the amount of hydrocarbons removed by water is negligible (1 % in each case). The addition of exogenous strains into the soil leads to the best biodegradation rate (39,3 % in 63 days). An endogenous bioaugmentation was tried but the efficiency was not demonstrated. On the other hand, the use of an artificial consortium was not more satisfying. Biostimulation alone led to a biodegradation rate of 23,9 % in 63 days. The lack of oxygen was avoided and evaluated through nitrite and ammonium concentrations in the water. These concentrations were negligible and always less than 2,5 and 1 mg/l, respectively. This work also tried to develop a special technique of monitoring of microbial ecology with microplates (Biolog ECO Micro PlateTM). The results were analysed through two different statistical methods : similarity rates and principal component analysis. It has been demonstrated that the column which leads to the best biodegradation rate also shows a particular metabolic profile, according to principal component analysis. The similarity rate is only 31 % with the initial microflora. This microflora seems to change during the experience because the similarity rate between the initial and the final microfloras is only 61 %. This work proved the efficiency of exogenous bioaugmentation compared with biostimulation. It proposes to apply this technique on a large scale, but only if the amount of polluted soil is evaluated before. [less ▲]

Bioremediation of diesel-polluted soils.

in Archives Internationales de Physiologie et de Biochimie (1995), 103(B46),

Bioresorbable and bioactive composite materials based on polylactide foams filled with and coated by Bioglass (R) particles for tissue engineering applications

in Journal of Materials Science: Materials in Medicine (2003), 14(5), 443-450

Poly(DL-lactide) (PDLLA) foams and bioactive glass (Bioglass®) particles were used to form bioresorbable and bioactive composite scaffolds for applications in bone tissue engineering. A thermally induced ... [more ▼]

Poly(DL-lactide) (PDLLA) foams and bioactive glass (Bioglass®) particles were used to form bioresorbable and bioactive composite scaffolds for applications in bone tissue engineering. A thermally induced phase separation process was applied to prepare highly porous PDLLA foams filled with 10wt% Bioglass® particles. Stable and homogeneous layers of Bioglass® particles on the surface of the PDLLA/Bioglass® composite foams as well as infiltration of Bioglass® particles throughout the porous network were achieved using a slurry-dipping technique. The quality of the bioactive glass coatings was reproducible in terms of thickness and microstructure. In vitro studies in simulated body fluid (SBF) were performed to study the formation of hydroxyapatite (HA) on the surface of the PDLLA/Bioglass® composites, as an indication of the bioactivity of the materials. Formation of the HA layer after immersion in SBF was confirmed by X-ray diffraction and Raman spectroscopy measurements. The rate of HA formation in Bioglass®-coated samples was higher than that observed in non-coated samples. SEM analysis showed that the HA layer thickness rapidly increased with increasing time in SBF in the Bioglass®-coated samples. The high bioactivity of the developed composites suggests that the materials are attractive for use as bioactive, resorbable scaffolds in bone tissue engineering. [less ▲]