Glutaraldehyde possesses unique characteristics that render it one of the most effective protein crosslinking reagents. It can be present in at least 13 different forms depending on solution ...conditions such as pH, concentration, temperature, etc. Substantial literature is found concerning the use of glutaraldehyde for protein immobilization, yet there is no agreement about the main reactive species that participates in the crosslinking process because monomeric and polymeric forms are in equilibrium. Glutaraldehyde may react with proteins by several means such as aldol condensation or Michael-type addition, and we show here 8 different reactions for various aqueous forms of this reagent. As a result of these discrepancies and the unique characteristics of each enzyme, crosslinking procedures using glutaraldehyde are largely developed through empirical observation. The choice of the enzyme-glutaraldehyde ratio, as well as their final concentration, is critical because insolubilization of the enzyme must result in minimal distortion of its structure in order to retain catalytic activity. The purpose of this paper is to give an overview of glutaraldehyde as a crosslinking reagent by describing its structure and chemical properties in aqueous solution in an attempt to explain its high reactivity toward proteins, particularly as applied to the production of insoluble enzymes.
L’adoption internationale se situe à un tournant de son histoire : depuis le milieu des années 2000, elle change de visage, véritable observatoire de l’évolution des sociétés à travers le monde. Le ...désir d’enfant semble se prolonger avec l’espérance de vie, parfois sans souci des niveaux de générations. Ce sont désormais des projets complexes qu’il faut accompagner en prenant en compte au plus près les critères propres à chaque pays, le profil des familles et celui des enfants adoptables (fratries, enfants grands, malades, au passé carentiel, voire traumatique). La multitude d’acteurs impliqués dans cette procédure exige des pratiques renouvelées, un effort créatif en matière d’outils et de supports d’information, et une coordination à chaque étape afin d’offrir aux futurs parents une préparation adaptée à cette réalité. De même, du fait des risques connus découlant de cette évolution, un regard ouvert sur le monde ainsi qu’une prise de conscience s’imposent chez chaque adoptant afin de lui permettre de se représenter au mieux ce qu’ont pu vivre ces enfants dans leurs pays.
Depuis 2007, le nombre d'enfants etrangers proposes a l'adoption par l'intermediaire de l'Agence francaise de l'adoption (AFA) evolue a la baisse : c'est aussi le cas pour les organismes autorises a ...l'adoption (OAA) en France et les operateurs en adoption internationale partout dans le monde. A cette evolution quantitative correspond une modification du profil des enfants, dont une part croissante sent des enfants dits ' a besoins specifiques '. Get article vise a presenter le profil sociodemographique des parents francais et de leurs enfants provenant d'autres pays d'Europe adoptes par l'intermediaire de l'AFA entre 2007 et 2010. Les resultats sent issus de l'exploitation statistique d'une des bases de donnees de cette agence. Deux caracteristiques majeures emergent de l'analyse du profil sociodemographique de ces parents adoptants : ils sont plus ages et plus souvent celibataires que les aut res parents adoptifs. Si les femmes celibataires se voient proposer davantage d'enfants dits ' a besoins specifiques ', elles les refusent plus frequemment, en raison vraisemblablement d'un accompagnement approfondi des families : en tant que service public, l'Agence dispose d'une equipe composee d'un medecin et d'une psychologue exercant a temps plein. Since 2007, the number of children proposed for adoption by the French Adoption Agency (Agence francaise de l'adoption) has been in decline. This phenomenon can also be observed in other organizations authorized to implement adoptions in France and internationally, and is generally found worldwide. Along with this quantitative evolution, a qualitative change can also be observed : the profile of the children proposed for adoption has changed and increasingly includes more children with 'special needs'. This article aims to present the socio-demographic profiles of French parents and of their children from other European countries, adopted through the French Adoption Agency between 2007 and 2010, based on statistical analysis of one of the databases of the Agency. Two major differences emerge from the analysis of the socio-demographic profiles of parents applying to adopt through the French Adoption Agency compared to other adoptive parents : they are older and more often single. While single women are more likely to be offered children with 'special needs', they also more often refuse offers, probably because they have been better informed through the close support provided for families by the Agency, which, as a public service, has its own staff team consisting of a doctor and a full-time psychologist. Adapted from the source document.
The immobilization conditions and kinetic behaviour of trypsin, covalently immobilized via the 1,4-diisothiocyanatobenzene (DITC) linker onto aminopropylated controlled pore glass (CPG) particles, ...have been evaluated to establish a rapid and efficient protocol for fabrication of an immobilized enzyme microreactor (IMER) for protein hydrolysis and subsequent peptide mapping. Addition of calcium ions to either the immobilization reaction solution or hydrolysis assay was studied for a synthetic substrate. Activity was slightly higher when immobilization was carried out in the presence of Ca
2+ whereas more enzyme could be immobilized in its absence. A protocol requiring less than 3
h was devised to obtain maximal enzymatic activity with the lowest ratio of soluble trypsin to DITC–CPG particles. The resulting immobilized enzyme was found to retain an acceptable percentage (
ca. 35%) of its activity after immobilization. The particles were dry-packed into a capillary to make a microscale IMER. Repeatability, reusability and digestion efficiency of the μIMER were investigated for the substrate β-casein using capillary electrophoretic-based peptide mapping. In initial tests, a single device showed reproducible peptide maps for 21 digestions lasting 2
h each, carried out over a period of 2 months. Complete digestion of β-casein could be achieved in a few minutes (86
s residence time in the μIMER followed by a wash step).
En 2011, en France, il n'existait aucune association de parents d'enfants exposés à l'alcool in utero. Brutalement confrontées aux graves conséquences des troubles causés par l'alcoolisation fœtale ...et scandalisées par le manque de soutien reçu de la part des professionnels de l'enfance, des familles se sont constituées en association. En lien avec l'association SAF France et avec l'appui de la Caisse Nationale de Solidarité pour l'Autonomie, Vivre avec le SAF a su trouver sa place, au niveau national, auprès des réseaux sanitaires spécialisés, des médias et des pouvoirs publics.
Biocompatible solid-phase microextraction (SPME) devices were prepared using two restricted access materials (RAM) as the SPME coating. The restricted access materials were immobilized on steel and ...platinum wires. The selective coating eliminated most of the matrix interference, which allowed the coupling to mass spectrometry without further purification. The SPME devices were interfaced to mass spectrometry by electronanospray. Several experimental set-ups are described and discussed herein. For the in situ extraction of peptides from the tryptic digests, trypsin was immobilized both on steel wires and on the inside wall of a vial. The devices were incubated together with the RAM–SPME devices and a protein (casein) solution. After the protein digestion, the resulting peptides were analyzed by SPME/nanospray. The vial approach provided the best results; up to eight peptides could be identified which corresponds to a sequence coverage of 58%. The limit of detection of SPME/nanospray for the extraction of peptides from an aqueous solution was about 50
fmol/mL. The results demonstrate that the direct coupling of SPME to nanospray can reduce analysis time and is an attractive alternative to conventional approaches like Zip–Tip purification.
Stabilization of proteolytic enzymes, especially by immobilization, is of considerable interest because of their potential applications in medicine and the chemical and pharmaceutical industries. We ...report here a detailed comparison of two procedures for trypsin immobilization using the same homobifunctional agent, glutaraldehyde, for the purpose of peptide mapping. These methods include covalent coupling either to controlled pore glass (solid support) or via a cross‐linking reaction (without any solid support). The immobilized trypsin preparations were characterized by the determination of immobilization efficiency, which ranged from 68 to > 95%, and measurement of apparent kinetic parameters toward a synthetic peptide‐like substrate. Batch digestions of whole denaturated human normal adult hemoglobin (HbA) were performed to obtain peptide maps by capillary zone electrophoresis (CZE). Migration time reproducibility of the CZE maps was excellent, with a mean relative standard deviation of 1.5%. Moreover, the two immobilized enzyme preparations showed excellent reproducibility for repeated digestions. Matrix‐assisted laser desorption/ionization (MALDI)‐mass spectrometry was also used for peptide mass mapping of denaturated HbA digested using the two immobilized trypsin preparations. Even though the two immobilized trypsin preparations do not behave identically, similar sequence coverages of 57% and 61% (for the two HbA chains merged) were achieved for the support‐based and cross‐linked trypsin preparations, respectively.
Trypsin was immobilized using glutaraldehyde either by covalent attachment to aminopropyl controlled pore glass (CPG) or by direct crosslinking without a carrier. As peptide mapping is a comparative ...method, reproducibility of the analytical separation techniques (liquid chromatography, HPLC, and capillary zone electrophoresis, CZE) and the proteolyses resulting from both enzyme preparations were evaluated. Elution time reproducibilities of 0.3 and 0.6% were found for HPLC and CZE maps, respectively. Proteolysis reproducibility was tested for each trypsin preparation and compared with solution phase proteolysis. Sequence coverages of ca 65% were obtained from matrix-assisted laser desorption/ionization−time-of-flight (MALDI-TOF) mass spectral mapping for the two solid phase preparations.
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