Academic literature on the topic 'Lactosan A/S'

ABSTRACT The oral bacterium Streptococcus salivarius takes up lactose via a transporter called LacS that shares 95% identity with the LacS from Streptococcus thermophilus, a phylogenetically closely related organism. S. thermophilus releases galactose into the medium during growth on lactose. Expulsion of galactose is mediated via LacS and stimulated by phosphorylation of the transporter by HPr(His∼P), a phosphocarrier of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS). Unlike S. thermophilus, S. salivarius grew on lactose without expelling galactose and took up galactose and lactose concomitantly when it is grown in a medium containing both sugars. Analysis of the C-terminal end of S. salivarius LacS revealed a IIA-like domain (IIALacS) almost identical to the IIA domain of S. thermophilus LacS. Experiments performed with purified proteins showed that S. salivarius IIALacS was reversibly phosphorylated on a histidine residue at position 552 not only by HPr(His∼P) but also by HPr(Ser-P)(His∼P), a doubly phosphorylated form of HPr present in large amounts in rapidly growing S. salivarius cells. Two other major S. salivarius PTS proteins, IIABL Man and IIABH Man, were unable to phosphorylate IIALacS. The effect of LacS phosphorylation on growth was studied with strain G71, an S. salivarius enzyme I-negative mutant that cannot synthesize HPr(His∼P) or HPr(Ser-P)(His∼P). These results indicated that (i) the wild-type and mutant strains had identical generation times on lactose, (ii) neither strain expelled galactose during growth on lactose, (iii) both strains metabolized lactose and galactose concomitantly when grown in a medium containing both sugars, and (iv) the growth of the mutant was slightly reduced on galactose.

Despite the widespread use of Streptococcus thermophilus as a starter culture in the manufacture of many fermented dairy products, only recently has an understanding of the basic processes regarding carbohydrate metabolism been developed. Although S. thermophilus is related to other lactic streptococci by virtue of their common use in dairy fermentations, available information indicates that S. thermophilus is serologically, genetically, and physiologically distinct from the Group N, mesophilic streptococci. Carbohydrate metabolism, in particular, occurs by different processes in S. thermophilus than in the Group N streptococci (Streptococcus lactis and Streptococcus cremoris). The latter organisms utilize lactose by a specific phosphoenolpyruvate-dependent phosphotransferase system in which the lactose hydrolysis products, glucose and galactyose-6-phosphate, are concurrently metabolized to lactic acid. In contrast, S. thermophilus lacks phosphotransferase activity and instead possesses a lactose permease. After hydrolysis by β-galactosidase, only glucose is further metabolized and galactose is released into the extracellular medium. Most strains are unable to ferment galactose and are phenotypically galactose-negative. The rapid growth rates of S. thermophilus on lactose and slow growth rates on glucose and galactose are likely due to the differences between the lactose and monosaccharide transport activities. Galactose transport by S. thermophilus requires an exogenous energy source and is mediated by a galactose permease. Galactose is further metabolized in galactose-positive cells by the enzymes of the Leloir pathway, specifically, galactokinase, galactose-1-phosphate uridyl transferase, and uridine-5-diphospho-glucose-4-epimerase. The latter two enzymes are eonstituitively expressed; however, in galactose-positive cells galactokinase and the galactose permease are induced by galactose in the absence of lactose. The phenotypic differences between galactose-positive and galactose-negative S. thermophilus are, in part, due to differences in the galactokinase and galactose permease activities. Galactose released into the medium by lactose-grown, galactose-positive cells can be subsequently metabolized, homofermentatively, to lactic acid. However, the important practical implications of released galactose has produced the need for isolation and development of S. thermophilus strains which ferment the lactose components, glucose and galactose, completely and simultaneously.

ABSTRACT The lactic acid bacterium Streptococcus thermophilus is widely used by the dairy industry for its ability to transform lactose, the primary sugar found in milk, into lactic acid. Unlike the phylogenetically related species Streptococcus salivarius, S. thermophilus is unable to metabolize and grow on galactose and thus releases substantial amounts of this hexose into the external medium during growth on lactose. This metabolic property may result from the inability of S. thermophilus to synthesize galactokinase, an enzyme of the Leloir pathway that phosphorylates intracellular galactose to generate galactose-1-phosphate. In this work, we report the complementation of Gal− strain S. thermophilus SMQ-301 with S. salivarius galK, the gene that codes for galactokinase, and the characterization of recombinant strain SMQ-301K01. The recombinant strain, which was obtained by transformation of strain SMQ-301 with pTRKL2TK, a plasmid bearing S. salivarius galK, grew on galactose with a generation time of 55 min, which was almost double the generation time on lactose. Data confirmed that (i) the ability of SMQ-301K01 to grow on galactose resulted from the expression of S. salivarius galK and (ii) transcription of the plasmid-borne galK gene did not require GalR, a transcriptional regulator of the gal and lac operons, and did not interfere with the transcription of these operons. Unexpectedly, recombinant strain SMQ-301K01 still expelled galactose during growth on lactose, but only when the amount of the disaccharide in the medium exceeded 0.05%. Thus, unlike S. salivarius, the ability to metabolize galactose was not sufficient for S. thermophilus to simultaneously metabolize the glucose and galactose moieties of lactose. Nevertheless, during growth in milk and under time-temperature conditions that simulated those used to produce mozzarella cheese, the recombinant Gal+ strain grew and produced acid more rapidly than the Gal− wild-type strain.

ABSTRACT To study the influence of phosphoglucomutase (PGM) activity on exopolysaccharide (EPS) synthesis in glucose- and lactose-growingStreptococcus thermophilus, a knockout PGM mutant and a strain with elevated PGM activity were constructed. ThepgmA gene, encoding PGM in S. thermophilusLY03, was identified and cloned. The gene was functional inEscherichia coli and was shown to be expressed from its own promoter. The pgmA-deficient mutant was unable to grow on glucose, while the mutation did not affect growth on lactose. Overexpression of pgmA had no significant effect on EPS production in glucose-growing cells. Neither deletion nor overexpression of pgmA changed the growth or EPS production on lactose. Thus, the EPS precursors in lactose-utilizing S. thermophilus are most probably formed from the galactose moiety of lactose via the Leloir pathway, which circumvents the need for a functional PGM.

La comunidad de Ojos Negros está ubicada en el municipio de Ensenada Baja California, México. Desde 1930, los residentes locales fabrican un queso artesanal muy apreciado en la región; sin embargo, la leche cruda y el queso nunca han sido analizados por la calidad microbiológica y de higiene del producto final. El objetivo del presente estudio fue evaluar la calidad microbiológica, física y química de la leche cruda utilizada para producir queso y el queso artesanal producido en las 22 unidades de producción individuales. Se tomaron muestras de queso y leche de las unidades de producción para realizar pruebas microbiológicas. Se realizaron determinaciones físicas y químicas de proteínas, grasas y lactosa utilizando un analizador LACTOSCAN-S. Los resultados del análisis de la leche mostraron un contenido de proteína (33,11 g/l) y grasa (39,89 g/l) dentro de los parámetros de la normatividad. Para la calidad microbiológica de la leche, los resultados del recuento de mesófilos aeróbicos mostraron un cumplimiento del 64% con las regulaciones; sin embargo, el mismo conteo de mesófilos aeróbicos en las muestras de queso resultó en solo el 4% de cumplimiento con las regulaciones. No hubo detección de Salmonella spp. o Listeria monocytogenes en cualquiera de las muestras de leche o de queso probadas. Se deben incorporar buenas prácticas sanitarias y de fabricación para mejorar la calidad sanitaria y de higiene para la producción de queso artesanal en la comunidad de Ojos Negros.

Dans le présent travail, l’électro-isomérisation du lactose en lactulose a été étudiée. Les variables indépendantes mises à l’étude dans ce projet sont : 1) l’effet de la concentration du lactose (5 et 10%), l’effet de la densité du champ électrique appliqué au réacteur d’électro-activation (100 et 200 mA). L’électro-isomérisation du lactose à 5% a été également comparée à celle observée dans du lactosérum ayant une concentration de lactose  5%. Les variables réponse principales (variables dépendantes) mises à l’étude étaient le taux de conversion du lactose en lactulose, le taux de formation de sous-produits de la réaction et l'efficacité du procédé exprimée en termes de résistance électrique globale du système d’électro-activation. Une surface totale de l’aire cathodique de 21,5 cm2 a été utilisée, donnant ainsi des densités de courant électrique de 4,65 et 9,30 mA/cm2, respectivement. Les analyses statistiques des données obtenues ont montré que l’effet du temps d’électro-activation sur le taux d’électro-isomérisation du lactose (rendement de formation de lactulose) ainsi que la résistance électrique du réacteur électro-activation était significatif. Le processus d’électro-activation a été réalisé pendant 60 min et des échantillons ont été prélevés chaque 10 min. Les résultats obtenus ont montré la grande efficacité de l'électro-activation, en tant qu’approche novatrice, pour transformer le lactose en lactulose. Après 60 min d’électro-activation à température ambiante (23  1  C), 25% de rendement d’électro-isomérisation a été obtenu. En excluant le lactose, la pureté du produit final était de 96,28  0,18%. En outre, aucune formation d’epilactose n’a été observée. De façon non systématique, du galactose a été détecté dans certains échantillons (<1,5%) et seulement quelques traces de fructose ont été observées (<0,31%). La résistance électrique globale du réacteur d’électro-activation diminuait avec l’augmentation du temps d'électro-activation, indiquant une grande efficacité énergétique de cette nouvelle technologie d’isomérisation du lactose en lactulose.
In the present work, electro-isomerization of lactose into lactulose has been studied. Effects of lactose concentration (5 and 10%) and applied DC-electric field (100 and 200 mA) on the electro-isomerization of lactose into lactulose and on process efficiency were investigated. Total cathode area of 21.5 cm2 was used; giving electric current density of 4.65 mA/cm2 and 9.30 mA/cm2, respectively. Milk whey permeate (4.7  0.15% lactose) obtained by ultrafiltration was also used as feed solution in the electro-activation reactor. The effect of processing time on lactose electro-isomerization rate (lactulose formation yield), by-product (glucose, galactose, epilactose and fructose) formation, and global electric resistance of the electro-activation reactor has been investigated. The process was run during 60 min and samples were taken every 10 min. Obtained results showed the high effectiveness of the developed electro-activation technology to convert lactose into lactulose. After 60 min electro-activation at ambient temperature (23  1 C), 25% electro-isomerisation yield was obtained. By excluding lactose, the end product purity was 96.28  0.18%, which is similar to the pharmakopoeia requirements for lactulose powder. Moreover, no epilactose was formed. Not systematically, galactose was detected in some samples (<1.5%) and only some traces of fructose were detected (<0.31%). The global electric resistance of the electro-activation reactor decreased as the electro-activation time was increased indicating the high energetic effectiveness of this new electro-isomerization technology.

L'isomérisation alcaline du lactose en lactulose a été effectuée électro-chimiquement à l’aide d’un réacteur d'électro-activation en combinaison avec des résines échangeuses d'anions de polystyrène de trois types; à savoir Lewatit VP-OC-1065 faible-acide, Lewatit MP-64 moyenne-acide et Lewatit Monoplus M500 forte-acide. Les paramètres opératoires qui ont fait l’objet de cette étude ont été étudiés sur trois blocs expérimentaux pour optimiser le système. Dans le Premier bloc, les paramètres étudiés sont : (1) ratio lactose-5%(p/v) : résine échangeuse d'anions (1:0.5, 1:1 et 1:2), (2) intensité du champ électrique : 50 mA, 100 mA et 200 mA et (3) type de résines : faible, moyenne et forte. Dans le Deuxième bloc, les paramètres mis à l’étude comprenaient : (1) l’intensité du champ électrique : 300 mA, 450 mA et 550 mA, (2) le débit de la solution traitée : 25 ml / min, 50 ml/ min et 100 ml/min et (3) la surface active de la membrane adjacente au compartiment cathodique : 0.78 cm2, 7.06 cm2 et 18.1 cm2. Le Troisième bloc expérimental a été effectué sur la base de la distance entre la membrane et l'électrode : 3.1 cm, 5.6 cm et 9 cm. Le même modèle expérimental a était également réalisé avec du perméat du lactosérum d’une concentration de 7% (p/v). Les résultats obtenus ont révélé que le meilleur rendement de l’isomérisation du lactose en lactulose était obtenu après 30 minutes d’électroactivation en utilisant une solution modèle de lactose-5% avec une valeur d’environ 20.1%. Les conditions opératoires qui ont permis d’avoir ce taux de conversion sont une intensité du courant de 550 mA, un débit de la solution de 25 ml/min, une surface active de la membrane de 7.06 cm2 et une distance de 9 cm entre la cathode et la membrane qui lui y est adjacente. En utilisant le perméat de lactosérum-7%, un taux de conversion de lactose en lactulose de 8.34% a était obtenu avec une intensité du courant de 200 mA, un débit de 120 ml/min, une surface active de de 18.1cm2 et une distance de 9 cm entre la membrane et l’électrode dans le compartiment cathodique. Les analyses de variance ont indiqué un effet catalytique significatif du type de la résine. En effet, la résine-forte a permis d’avoir les plus hauts rendements de la réaction d’isomérisation par électro-activation. La résistance électrique globale du système d’électroactivation dépendait de la valeur de l’intensité du courant. Le produit final était d’une grande pureté, car il ne présentait que quelques traces de galactose (< 4%).
The isomerization of lactose to lactulose in alkaline conditions was carried out electrochemically using an electro-activation reactor in combination with three types of anion-exchange polystyrene resins, namely Lewatit VPOC 1065 weak acid, Lewatit MP-64 medium acid, and Lewatit Monoplus M500 strong acid. The operational parameters evaluated in this study have been adjusted to three blocks to optimize the system: first block: a) ratio lactose- 5% (w /v): anionexchange resin (1:0.5, 1:1 and 1:2), b) electric field intensity of 50 mA, 100 mA, and 200 mA, and c) resin type; second block: a) electric field intensity of 300 mA, 450 mA, and 550 mA, b) flow rate (25 ml / min, 50 ml / min, and 100 ml / min); and c) area of the membrane adjacent to the cathode compartment (0.78 cm2,7.06 cm2, and 18.1 cm2); and third block: distance between the membrane and the electrode (3.1 cm, 5.6 cm, and 9 cm). The same experimental model was used with whey permeat at a concentration of 7% (w/v). Obtained results revealed that the best yield was obtained after 30 minutes of electro-activation using a typical solution based on 20.1% of lactose-5% under a current intensity of 550 mA, a flow rate of 25 ml / min, a membrane area of 7.06 cm2, and a distance of 9 cm between the membrane and the electrode. The use of whey permeate-7% resulted in 8.34% of lactulose under a current intensity of 200 mA, a flow rate of 120 ml / min, a membrane area of 18.1 cm2, and a distance of 9 cm in the cathodic compartment. The analysis of variance indicated a significant catalytic effect on the resin type since the strong acid resin allowed obtaining the highest yields of the isomerization reaction by electro-activation. The overall electrical resistance of the electro-activation system depends on the current intensity. The final product was of high purity since it contains only few traces of galactose (< 4%).

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Metabolic syndrome (MS) is a complex disorder with a strong genetic basis and multifactorial etiology. Insulin resistance (IR) causes MS and it can be triggered by intestinal inflammation like the use of lactose in patients intolerant of this carbohydrate. It was found that variants in the lactase gene are associated with lactase non persistence LNP and MS in a population sample of Salvador/Bahia; and whether these variants are modifying the response to diet-therapeutic intervention in patients with this syndrome; also compared the biochemical test of lactose tolerance (LTT) with genetic diagnosis; and tested the association of mutations in the lactase gene with cofactors SM (TGL, HDL-C, blood pressure, glucose levels, waist circumference), with anthropometric variables (Arm Circumference, Body Mass Index, Hip Circumference, hip-waist ratio,lean massand fat mass percentages) and other factors associated with MS: insulin, total cholesterol, LDL-C, VLDL-C, C-reactive protein, HOMA-IR, renal function (creatinine, urea, uric acid, microalbuminuria) and vitamin D. There were two studies: a case-control with 257 cases (MS) and 210 controls and other clinical trial study, which was conducted with three types of diet in patients with metabolic syndrome: diet 1 - No lactose; Diet 2 - Lactose and energy restriction; Diet 3 - Only energy restriction. In all groups were also evaluated for nine SNPs in the lactase (LCT) gene. The genotyping of SNPs was carried out by TaqMan assays. Data were analyzed using SPSS, 20.0, and the Hardy-Weinberg Equilibriumhaplotype frequencies were calculated using Arlequin, 2000 program. The results showed that all diets improve several MSaspects after two months of intervention, especially in the diet 1, that also decreased inflammation, insulin resistance and dyslipidemia (LDL-C). In addition,it was the diet that most took out patients of the MS: 2.72 times more likely to get out of MS than diet 3. LNP was high in both cases and controls. There was compatibility between clinical diagnosis for LNP by Lactose Tolerance Test and two of the studied SNPs, they were rs4988253 and rs182549, those that have proved functional studies. Thus, it is suggested the analysis of LCT gene polymorphisms before the nutritional therapeutics for patients with MS, as well as to take out the lactose in their diet.
A S?ndrome Metab?lica (SM) ? uma desordem complexa, de forte base gen?tica e de etiologia multifatorial. Dentre as suas causas, encontra-se a Resist?ncia ? Insulina (RI) que pode ser desencadeada pela inflama??o intestinal, pelo uso de lactose em pacientes intolerantes a este carboidrato. Verificou-se quais variantes no gene da lactase est?o associados ? IL e SM em amostra da popula??o de Salvador/Bahia; e tamb?m se estas variantes s?o modificadoras da resposta ? interven??o dietoter?pica em portadores desta s?ndrome; comparou-se tamb?m o teste bioqu?mico de toler?ncia ? lactose (TTL) com o diagn?stico gen?tico; e testou-se a associa??o das muta??es no gene da lactase com os cofatores da SM (TGL, HDL-c, press?o arterial, glicemia, circunfer?ncia da cintura), com vari?veis antropom?tricas (circunfer?ncia do bra?o, ?ndice de massa corporal, circunfer?ncia do quadril, raz?o cintura quadril, percentual de massa magra e massa gorda) e com outros fatores associados ? SM: insulina, colesterol total, LDL-C, VLDL, Prote?na C reativa, HOMA-IR, fun??o renal (creatinina, ur?ia, ?cido ?rico, microalbumin?ria) e vitamina D. Foram realizados dois estudos: um caso-controle com 257 casos (SM) e 210 controles e outro estudo de tipo ensaio cl?nico, que foi realizado com tr?s tipos de dieta com os pacientes com SM: dieta 1 ? sem lactose; dieta 2 ? sem lactose e com restri??o energ?tica; Dieta 3 ? apenas restri??o energ?tica. Em ambos os grupos tamb?m foram avaliados 9 SNPs no gene da lactase. A genotipagem dos SNPs foi realizada pela tecnologia de ensaios TaqMan. Os dados foram analisados pelo programa SPSS ver 20.0 e a adequa??o das frequ?ncias genot?picas ao Equilibrio de Hardy-Weinberg e c?lculo da frequ?ncia dos hapl?tipos formados pelos polimorfismos foram obtidos atrav?s do programa Arlequin ver 2000. Os resultados mostraram que todas as dietas melhoram o quadro da SM ap?s dois meses de interven??o, com destaque para a dieta 1, que tamb?m diminuiu a inflama??o, resist?ncia ? insulina e a dislipidemia (LDL-C). Al?m disso foi a dieta que mais tirou paciente da SM: apresentou 2,72 vezes mais chances de sair da SM que a dieta 3. A intoler?ncia ? lactose foi alta tanto em casos como em controles. Houve compatibilidade do TTL com os SNPsrs4988253 e rs182549, os ?nicos que possuem estudos funcionais. Assim, sugere-se an?lise de polimorfismos do gene da lactase antes da prescri??o nutricional para pacientes com SM, bem como, a retirada da lactose da dieta.

Foi estudado o efeito da lactona sesquiterpênica licnofolido sobre o \"burst\" respiratório de leucócitos polimorfonucleares inflamatórios (PMN) estimulados por forbol (PMA), pelo peptídeo quimiotático fMLP ou zimozan opsonizado (OZ). O licnofolido inibiu de forma dose-dependente a liberação de O2•- pelos PMN, sem alteração do período \"Iag\" do complexo NADPH. oxidase. O efeito foi mais acentuado quando os PMN foram estimulados diretamente pela via de proteína quinase C. A adição de ditiotreitol ou glutationa reduzida (GSH) às suspensões celulares antes da incubação com licnofolido preveniu parcialmente o efeito inibitório. O tratamento dos PMN com a lactona determinou uma queda drástica dos níveis celulares de GSH livre, sem incremento de glutationa oxidada (GSSG). A reação direta entre GSH e licnofolido foi confirmada com a detecção de um aduto glutationil-licnofolido através de identificação por espectrometria de massa (ESI-MS/MS). A S-tiolação protéica induzida pelo PMA foi reduzida em PMN tratados com Iicnofo/ido, como detectado através de determinação de incorporação de [35S], sendo que 80% desses tióis foram identificados como GSH. Uma série de proteínas S-glutationadas foi detectada através de autoradiografias, sendo que aquelas correspondentes a 38 e 24 kDa tiveram essa modificação póstraducional suprimida pelo tratamento com dose de licnofolido capaz de suprimir o \"burst\" respiratório dos PMN. Estes resultados indicam que a depleção celular de GSH causada pelo licnofolido impede a sustentação do \"burst\" respiratório pelos PMN, em correlação direta com a diminuição de S-glutationação protéica.
An investigation was made into the action of the sesquiterpene lactone lychnopholide on the respiratory burst of inflammatory polymorphonuclear leukocytes. Lychnopholide determined concentration-related inhibition of the generation of phorbol 12-myristate 13-acetate-, chemotatic peptide-, and opsonized zymozan-induced superoxide anion with no effect on the lag time of the assembly of the NADPH oxidase complex, such action was greater on the protein kinase C pathway that on both membrane receptor dependent stimuli via. Subsequent additions of D-glucose, Ca2+, Mg2+, dithiothreitol ar reduced glutathione (GSH) did not reverse the inhibitory action. The addition of both thiols prior to the lychnopholide treatment partially hindered the inhibition rate. The endogenous level of GSH in leukocytes was drastically depleted under the lychnopholide treatment, without corresponding increases occurring in the oxidized form (GSSG). A direct reaction between glutathione and lychnopholide was confirmed from a glutathionyl-lychnopholide adduct detected by electrospray mass spectrometry analysis and identified by tandem mass analysis in cellular extracts. Protein S-thiolation induced by PMA stimulation was decreased in lactone-treated PMN as detected by [35S] scintillation count, which indicated that about 80% of the thiols were glutathione. A subset of S-glutathionylated proteins was identified through gel electrophoresis, which revealed that the modification of the phorbol-triggered protein sulfhydryl in the protein bands corresponding to 38 and 24 kDa was precluded by the lychnopholide treatment correlated with respiratory burst inhibition. These results show that GSH depletion determined by lychnopholide treatment renders PMN to sustain respiratory burst, whose action is proportional to protein S-glutahionylation decrease.

L'objectif de la présente thèse était de développer un nouveau procédé en vue de valoriser intégralement le perméat de lactosérum (WP) qui a un impact négatif important sur l'environnement en raison de sa forte demande biochimique et chimique en oxygène (DBO et DCO). Pour cela, le WP a été valorisé par isomérisation in situ de son lactose en lactulose prébiotique en utilisant la technologie d'électro-activation (EA) comme une nouvelle approche sans aucun prétraitement et/ou fractionnement en amont et en aval. Premièrement, les meilleures conditions d'isomérisation du lactose en lactulose en utilisant le WP comme source de lactose bon marché ont été déterminées. L'effet de l'intensité du courant électrique et du sel (CaCl2, KCl et MgCl2) sur la conversion du lactose en lactulose en utilisant des solutions de WP (6%, P/V) et de lactose pur (5%, P/V) ont été étudié. Le lactose a été converti en lactulose à un taux de 35,1% lorsque le KCl, une intensité de courant de 330 mA pendant 21 min d'EA ont été appliqués au WP; et 38,66% lorsque le KCl, une intensité de courant de 330 mA pendant 14 minutes ont été appliqué à une solution de lactose. L'utilisation de WP dans les compartiments central et cathodique sans addition de sel a donné un rendement de 39,78% de lactulose après 35 min d'EA à 330 mA. La microscopie électronique à balayage et le calcul de la résistance électrique globale du réacteur n'ont révélé aucun encrassement de la membrane. Deuxièmement, les solutions électro-activées cathodiques obtenues avec un rendement élevé en lactulose et les produits de réaction de Maillard induits (MRP) ont été soumis au séchage à trois températures (160, 180 et 200 °C) et leur activité antioxydante (AA) a été évaluée. Pour ce faire, l’AA a été évaluée par l'AA au DPPH, le pouvoir réducteur, le test au radical ABTS•+ et l’effet chélateur du fer. L'effet de la température de séchage sur l'AA du perméat de lactosérum électro-activé (EAWP) a également été évalué. Les données obtenues démontrent que l'EA améliore significativement l'AA du WP et que cette AA est principalement due aux MRP intermédiaires, comme le montre l'absorbance la plus élevée à 294 nm. De plus, les résultats ont montré que la température de séchage influençait significativement l'AA de l'EAWP. Enfin, l’effet de la concentration de poudre EAWP (EAWPP) obtenue (0%, 2%, 4% et 6%, P/P) sur l’oxydation des lipides et la stabilité de la couleur du bœuf haché stocké à 4 °C pendant 17 jours a été étudié. L'oxydation lipidique et l'apparence du bœuf haché ont été évaluées par la mesure des produits d'oxydation primaires (indice d'acide (AV) et de peroxyde (PV)) et secondaires (substances réactives à l'acide thiobarbutirique, TBARS), ainsi que par la mesure de la couleur dans le système CIELAB après 1, 2, 3, 10 et 17 jours. Les résultats démontrent que l'EAWPP agit comme un antioxydant efficace sur les lipides de la viande. Les analyses de l’AV, de PV et de TBARS démontrent que la viande de bœuf hachée réfrigérée additionnée de la poudre EAWPP inhibait l'oxydation des lipides par rapport au témoin. Ces résultats ont été également confirmés par l'analyse des acides gras de la fraction lipidique. De plus, la stabilité de la couleur a été sauvegardée lorsque la poudre EAWPP a été ajoutée. En conclusion, le procédé proposé peut, d’une part, résoudre le problème environnemental du WP en le transformant d’un sous-produit polluant en un ingrédient à haute valeur ajoutée ayant des propriétés prébiotiques et antioxydantes et, d’autre part, une alternative possible la synthèse chimique du lactulose réduisant ainsi son impact négatif sur l'environnement.
The aim of the present thesis was the development of a new process in view to the integral valorization of whey permeate (WP) which have a serious negative environmental impact due to it high biochemical and chemical oxygen demand (BOD, CDO) (COD). For this, WP was valorized through in situ isomerisation of it lactose into the prebiotic lactulose using electro-activation technology as a new approach without any upstream and/or downstream fractionation. Firstly, the best conditions of the isomerisation of lactose into lactulose using WP as a cheap lactose source were determined. The effect of electric current intensity and salt (CaCl2, KCl and MgCl2) on the amount of lactose conversion into lactulose by using WP (6 %, wt) and pure lactose (5 %, wt) solutions was studied. Lactose was converted into lactulose at a level of 35.1% when KCl, current intensity of 330 mA during 21 min of electro-activation were applied to WP; and 38.66% when KCl, current intensity of 330 mA during 14 min were applied to lactose solution. The use of WP in both the central and cathodic compartments without addition of salt yielded 39.78% lactulose after 35 min of electro-activation at 330 mA. Scanning electron microscopy and calculation of the global electrical resistance of the reactor did not reveal any membrane fouling. Secondly, the cathodic electro-activated solutions obtained with a high lactulose yield and induced Maillard reaction products (MRPs) were submitted to spray drying at three temperatures (160, 180 and 200 °C) and their antioxidant activity (AA) was evaluated. For this purpose, the AA was evaluated by the DPPH scavenging activity, reducing power, ABTS•+ Radical scavenging assay and iron chelating capacity. The effect of the drying temperature on the AA of the EAWP was also evaluated. The obtained data demonstrated that electro-activation significantly (P < 0.001) enhanced the AA of WP and that this AA was mainly due to the intermediate MRPs, as shown by the highest absorbance at 294 nm. Moreover, the results showed that the drying temperature significantly influenced the AA of EAWP. Finally, the effect of the obtained EAWP powder (EAWPP) concentration (0%, 2%, 4% and 6%, wt/wt) on lipid oxidation and color stability of chilled minced beef stored at 4°C for 17 days was investigated. The minced beef lipid oxidation and appearance were evaluated through measurement of primary (acid value (AV) and peroxide values (PV)) and secondary oxidation products (thiobarbutiric acid reactive substances, TBARS), together with measurement of color in the CIELAB system at 0, 1, 2, 3, 10 and 17 days. Results demonstrate that the EAWPP act as an effective antioxidant on lipid meat. The AV, PV and TBARS analysis demonstrate that the chilled minced beef added with the EAWPP inhibited the lipid oxidation compared to the control. This finding was also confirmed by the fatty acid analysis of the lipid fraction. In addition, the color stability was saved when EAWPP was added. In conclusion, the proposed process can, on one hand, solve the environmental problem of WP by transforming it from a pollutant by product into a high value added ingredient having prebiotic and antioxidant properties and, on the other hand, it constitutes a possible alternative to the chemical synthesis of lactulose thus reducing its negative environmental impact.

Le surplus mondial et le faible prix du lactose ont attiré l’attention de chercheurs et de l’industrie pour développer des procédés novateurs pour la production de dérivés du lactose à valeur ajoutée, tels que l’acide lactobionique (ALB), qui est un produit à haute valeur ajoutée obtenu par l’oxydation du lactose, avec d’excellentes propriétés pour des applications dans les industries alimentaire et pharmaceutique. Des recherches sur la production d’ALB via l’oxydation catalytique du lactose avec des catalyseurs à base de palladium et de palladium-bismuth, ont montré des bonnes conversions et sélectivités envers l’ALB. Cependant, le principal problème de ces catalyseurs est leur instabilité par lixiviation et désactivation par suroxydation au cours de la réaction. Les catalyseurs à base d’or ont montré une meilleure performance que les catalyseurs de bismuth-palladium pour l’oxydation de glucides. Cependant, trouver un catalyseur robuste pour l’oxydation du lactose est encore un grand défi. Dans cette dissertation, des nouveaux catalyseurs à base d’or supportés sur des matériaux mésostructurés de silicium (Au/MSM) ont été synthétisés par deux méthodes différentes, et évalués comme catalyseurs pour l’oxydation du lactose. Les catalyseurs ont été caractérisés à l’aide de la physisorption de l’azote, DRX, FTIR, TEM et XPS. Les effets des conditions d’opération, telles que la température, le pH, la charge d’or et le ratio catalyseur/lactose, sur la conversion du lactose ont été étudiés. Finalement, le procédé de déminéralisation de la solution de lactobionate de sodium à la sortie du réacteur a été étudié à l’aide de deux approches: l’électrodialyse avec des membranes bipolaires (EDMB) et la technologie d’échange d’ions. Des catalyseurs Au/MSM hautement actifs ont été synthétisés avec succès par la co-condensation d’un mélange de bis [3-(triéthoxysilyl) propyle] tétrasulfide (BTESPTS), tétra-éthyle ortho-silicate (TEOS) et le précurseur d’or (HAuCl4) en milieu acide, avec le tribloc co-polymère EO20PO70EO20 utilisé comme agent structurant. Il a été trouvé que l’augmentation du ratio molaire BTESPTS/TEOS provoque un changement dans la structure des matériaux, laquelle passe d’une structure 2D-hexagonal très ordonnée à une structure mixte de type hexagonal-vésicule et mousse cellulaire. Dans les conditions opératoires optimales (charge d’or = 0.7% en poids, T = 65ºC, catalyseur/lactose ratio = 0.2, pH = 8-9, débit d’air = 40 mL·min-1), le lactose a été complètement converti en ALB après 80-100 min de réaction, lorsqu’on a utilisé les catalyseurs synthétisés à partir des mélanges contenant une concentration molaire de BTESPTS entre 6-10%. Ces catalyseurs ont été caractérisés par une structure de type « wormhole-like », favorable pour l’accessibilité des réactifs aux nanoparticules d’or (AuNPs) d’environ 8 nm intercalées dans les murs de la silice. AuNPs d’environ 5-6 nm ont été aussi chargées avec succès sur les matériaux mésoporeux SBA-15 et SBA-15-CeO2, par l’adsorption du complexe [Au(en)2]3+ (en=éthylènediamine) en milieu alcalin. Ces catalyseurs ont conservé la structure hexagonale 2D très ordonnée typique de la SBA-15, et ils ont présenté une grande activité pour l’oxydation du lactose. Après 60 min de réaction, les catalyseurs Au/SBA-15-CeO2 (ratio molaire Ce/Si = 0.2) ont présenté l’activité catalytique la plus élevée (100% conversion du lactose) et 100% de sélectivité envers l’ALB, lorsqu’ils ont été utilisés dans les conditions optimales décrites ci-dessus. Ces résultats suggèrent que l’oxyde de cérium joue un rôle dans l’augmentation de l’activité catalytique, où la coordination et les états d’agglomération des atomes du Ce pourraient avoir un effet important. En général, les résultats des analyses XPS sur les états d’oxydation de l’or à la surface des Au/MSM, ont montré la coexistence d’espèces d’or métalliques et oxydées, avec une abondance relative suivant l’ordre Au0 >>>Au+1 > Au+3. Dans le cas des catalyseurs Au/SBA-15-CeO2, la présence des deux états d’oxydation Ce3+ et Ce4+ a été aussi observée. Les expériences de recyclage des catalyseurs ont montré que l’activité des échantillons Au/SBA-15 et Au/SBA-15-CeO2 a été significativement réduite (40-65%) après des cycles de réaction d’oxydation consécutifs, lorsque le lavage avec de l’eau a été utilisé comme procédé de régénération. Par contre, les catalyseurs ont conservé leur activité catalytique, en utilisant la calcination comme méthode de régénération, ce qui indique qu’une des causes de désactivation des catalyseurs Au/MSM pourrait être due à une forte adsorption d’espèces organiques sur la surface des catalyseurs. De plus des quantités significatives d’or ont été trouvées dans la solution après des cycles de réaction consécutifs, ce qui démontre la désactivation est aussi due à la lixiviation de la phase active dans la solution de réaction. Les données expérimentales ont révélé que tant l’EDMB que la technologie d’échange d’ions pourraient être utilisées pour produire l’ALB à partir de son sel de sodium. Cependant, en tenant compte du fait que l’EDMB a été utilisée pour la première fois pour cette application, ce procédé a donc besoin d’une amélioration pour des applications industrielles. En effet, une déminéralisation de 50% a été atteinte après l’application d’une différence de potentiel de 5.0-5.5 V pendant 100-180 min aux bornes d’une cellule d’électrodialyse à trois compartiments, tandis que la solution de lactobionate de sodium a été complètement dépourvue de sodium après 10-30 min, lorsqu’on a utilisé une résine échangeuse de cations commerciale fortement acide (AmberliteTM FPC23 H).
The worldwide surplus and low cost of lactose have drawn the attention of researchers and industry to develop innovative processes for the production of value-added lactose derivatives, such as lactobionic acid (LBA), which is a high value-added product obtained from lactose oxidation, with excellent properties for applications in the food and pharmaceutical industries. Investigations on LBA production by means of catalytic oxidation of lactose over palladium and bismuth-palladium supported catalysts have shown good conversion rates and selectivities towards LBA, but the main problem of these catalysts is their instability by leaching and deactivation by over-oxidation during the reaction. Supported gold catalysts have shown to outperform palladium and bismuth-palladium catalysts for the oxidation of carbohydrates. However, there is still a big challenge in finding a robust catalyst for the lactose oxidation. In this dissertation, new gold catalysts supported on mesoporous silica materials (Au/MSM) have been synthesized by two different methods, and evaluated as catalysts in the oxidation of lactose. The catalytic materials were characterized by nitrogen physisorption, XRD, FTIR, TEM and XPS. The effects of the operating conditions such as temperature, pH, gold loading and catalyst/lactose ratio on the lactose conversion were investigated. Finally, the demineralization process of the sodium lactobionate solution obtained at the reactor outlet has been studied using two approaches: bipolar membrane electrodialysis (BMED) and ion-exchange technology. Highly active Au/MSM were successfully formulated by the co-condensation of a mixture of bis [3-(triethoxysilyl) propyl] tetrasulfide (BTESPTS), tetraethyl orthosilicate (TEOS) and the gold precursor (HAuCl4) in acidic media, using the triblock co-polymer EO20PO70EO20 as template. It was found that by increasing the BTESPTS/TEOS molar ratio, the structure of the synthesized materials changed from a highly ordered 2D hexagonal structure to a mixed hexagonal-vesicle and cellular foam structure. Under the optimal operating conditions (gold loading = 0.7%wt, T = 65ºC, catalyst/lactose ratio = 0.2, pH = 8-9, air flow = 40 mL·min-1), the lactose was completely converted into LBA after 80-100 min reaction, when using the catalysts synthesized from mixtures containing 6-10% molar concentration of BTESPTS. These catalytic materials were characterized by the predominance of a wormhole-like structure, favorable for the reagent accessibility to the gold nanoparticles (AuNPs) of about 8 nm intercalated in the silica walls. AuNPs of about 5-6 nm were also successfully loaded of mesoporous SBA-15 and SBA-15-CeO2 materials, by the wet adsorption of the gold cationic complex [Au(en)2]3+ (en=ethylenediamine) in alkaline media. These catalysts retained the well-ordered 2D hexagonal structure typical of SBA-15, and showed high activity to lactose oxidation. After 60 min of reaction, the Au/SBA-15-CeO2 catalysts (Ce/Si = 0.2) showed the highest catalytic activity (100% lactose conversion) and 100% selectivity towards LBA, when used at the optimal operating reaction conditions described above. These results suggest that ceria plays a role in the enhancement of the catalytic activity, where the coordination and agglomeration states of Ce atoms could have an important effect. In general, the XPS study on the oxidation states of gold on the Au/MSM surfaces revealed the coexistence of metallic and oxidized Au species, whose relative abundance followed the order Au0 >>>Au+1 > Au+3. In the case of Au/SBA-15-CeO2 catalysts, the presence of both Ce3+ and Ce4+ oxidation states was also observed. Catalysts’ recycling experiments showed that the activity of Au/SBA-15 and Au/SBA-15-CeO2 was significantly reduced (40-65%) after consecutive oxidation reaction cycles, when washing with water was used as regeneration process. On the contrary, these catalytic samples conserved their catalytic activity when calcination was used as regeneration method, indicating that one of the causes of deactivation of Au/MSM might be the strong adsorption of organic species on the catalyst surface. Moreover, significant amounts of Au were found in the solution after consecutive reaction cycles, demonstrating that the leaching of the active phase into the reaction solution is another important cause of the catalyst’ deactivation. Experimental data showed that both BMED and ion exchange technology might be used for producing LBA from its sodium salt. However, taking into account that it is the first time that BMED is used for this application, this process still needs further improvement for industrial applications, since a demineralization rate of 50% was achieved after applying a voltage difference of 5.0-5.5 V during 100-180 min to a three-compartment electrodialysis stack, while a complete sodium removal was achieved after 10-30 min when using a commercial strong cation exchange resin (AmberliteTM FPC23 H).

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Canine demodicosis is an inflammatory skin disease, frequently diagnosed in veterinary clinics, caused by the proliferation of mites of the species Demodex sp. In recent years, important findings about the disease have been reported, mainly aspects related to treatment, with the insertion of new molecules or new treatment regimens. Doramectin is a macrocyclic lactone that has been used empirically by veterinarians, who use different routes, doses and intervals in its administration, with no homogeneus results. This study aimed to evaluate the use of doramectin in the treatment of dogs affected by the generalized form of demodicosis. Of the forty-six dogs diagnosed with the disease during the study, 20 were selected for the study and divided into three groups: Group I ? treated with doramectin at a dose of 600 mcg/kg once a week orally, group II ? treated at a dose of 300 mcg/kg orally every 3 days and group III ? treated at a dose of 600 mcg/kg every 7 days subcutaneously. The animals were treated until three consecutive negative skin scrapings were obtained, with intervals of at least fifteen days between them (parasitological cure). The days required to obtain the parasitological cure were 105, 82 and 100 according to the indicated groups; and their treatment efficiencies were 75, 100 and 83%, respectively. Doramectin was effective in treating generalized demodectic mange in dogs, regardless of the dose, route and interval of administration. However, the best results were obtained in the group treated at a dose of 300 mcg/kg orally every 3 days. There were no reported adverse reactions with the use of macrocyclic lactone.
Demodiciose canina ? uma doen?a inflamat?ria da pele, frequentemente diagnosticada nos consult?rios veterin?rios, causada pela prolifera??o de ?caros da esp?cie Demodex sp. Nos ?ltimos anos, importantes descobertas sobre a doen?a foram reportadas, principalmente os aspectos relacionados ao tratamento, com a inser??o de novas mol?culas ou novos esquemas de tratamento. A doramectina ? uma lactona macroc?clica que vem sendo usada de forma emp?rica por m?dicos veterin?rios, que a utilizam por diferentes vias, doses e intervalos na sua administra??o, com resultados heterog?neos. O objetivo do estudo foi avaliar a utiliza??o da doramectina no tratamento da demodiciose generalizada em c?es. Dos 46 animais diagnosticados com a doen?a, 20 foram selecionados e divididos em tr?s grupos experimentais: grupo I ? tratado com doramectina dose de 600 mcg/kg semanalmente por via oral, grupo II ? tratado na dose de 300 mcg/ kg por via oral a cada 3 dias e o grupo III ? tratado na dose de 600 mcg/kg a cada 7 dias por via subcut?nea. Os animais foram tratados at? a obten??o de tr?s raspados negativos consecutivos com pelo menos 15 dias de intervalo entre eles (cura parasitol?gica). Os dias necess?rios para obten??o da cura parasitol?gica foram 105, 82 e 100 de acordo com os grupos assinalados e as respectivas efic?cias ao tratamento foram 75, 100 e 83%. A doramectina demonstrou ser eficaz no tratamento da demodiciose generalizada em c?es independente da dose, via e intervalo de sua administra??o. Entretanto, os melhores resultados obtidos foram observados no grupo tratado com a dose de 300 mcg/ kg por via oral a cada 3 dias. N?o foram reportadas quaisquer rea??es adversas com a utiliza??o da lactona macroc?clica.

Le lactosucrose est un trisaccharide synthétisé par la bioconversion du lactose et du saccharose en utilisant la β-galactosidase à partir d’Aspergillus oryzae. La production industrielle du lactosucrose est onéreuse à cause du coût élevé des enzymes, d’où le recours à immobiliser ces enzymes. Dans cette optique, sept différents matériaux siliceux mesostructurés ont été utilisés pour immobiliser la β-galactosidase, en utilisant le glutaraldhéyde. La majorité des matériaux présente une bonne activité. Cependant, l’enzyme immobilisée sur la silice en forme de mousse montre un rendement maximal, dépassant celui de l’enzyme libre. En plus, un rendement équivalent à 75% de celui obtenu à la première utilisation du matériau est maintenu pour la plupart des biocatalyseurs, après un 5ème recyclage. Une concentration équimolaire de 60% entre les substrats, un pH de 5 et une température de 40°C se sont révélés optimaux pour la production du lactosucrose qui a atteint une concentration de 76,27 g/L.
Les oligosaccharides sont des glucides qui modulent la flore colique et améliorent l’équilibre de la santé humaine. Ils sont largement utilisés comme prébiotiques. Le lactosucrose est un oligosaccharide qui attire de plus en plus le milieu scientifique et industriel. Il est un trisaccharide (Glucose-Fructose-Galactose), non digestible avec un pouvoir sucrant faible. Ce trisaccharide peut être synthétisé par voie enzymatique, via la bioconversion du lactose et du saccharose, et ceci en utilisant la levansucrose, la fructofuranosidase ou la β-galactosidase. Durant ce travail, la β-galactosidase extraite à partir d’Aspergillus oryzae a été utilisée pour synthétiser le lactosucrose. Dans un premier temps, et afin d’optimiser le rendement en lactosucrose, nous avons étudié différents paramètres avec l’enzyme libre. Une concentration équimolaire de 60% entre le lactose et le saccharose, un pH de 5 et une température de 40°C se sont révélés optimaux pour la production du lactosucrose. L’optimum est obtenu avec un rendement de 25% (76,27 g/L) en lactosucrose. Un sous-produit a été isolé, il s’agit d’un autre oligosaccharide (tetrahexose) avec une concentration de 14,52 g/L. La production actuelle du lactosucrose et d’autres oligosaccharides à l’échelle industrielle est onéreuse due au coût élevé des enzymes, d’où le recours à immobiliser celles-ci pour pouvoir les recycler et les réutiliser et par conséquent, minimiser les coûts de production. Dans cette deuxième partie, nous avons utilisé sept différents matériaux siliceux pour immobiliser l’enzyme (β-galactosidase d’Aspergillus oryzae) en utilisant le glutaraldéhyde (GA) comme agent de ‘cross-linking’, et effectuer la réaction de transglycosylation par la suite dans une approche hétérogène et comparer le rendement de la réaction avec celui de l’enzyme libre (approche homogène). Les matériaux synthétisés ont différentes tailles de pores qui varient de 5 à 24 nm et aussi différentes formes poreuses (hexagonale, cubique, sphérique, forme d’oignon, etc.). Cette différence de taille et de forme a affecté énormément la rétention enzymatique par ces matériaux ainsi que le rendement de la réaction en phase hétérogène. La majorité des matériaux synthétisés présentent une bonne activité. Cependant, l’enzyme immobilisée sur la silice en forme de mousse (MCF) montre un rendement maximal, qui dépasse celui obtenu par l’enzyme libre, ce qui confirme que l’immobilisation d’enzyme sur des supports siliceux mesostructurés peut conférer à l’enzyme des conditions réactionnelles améliorées afin d’augmenter sa stabilité et par conséquent sa performance. Le recyclage de ces biocatalyseurs a été effectué 5 fois successives. Le rendement obtenu à la 5ème régénération est équivalant à plus que 80% du rendement initial pour la majorité des matériaux testés.

L’induction de la tolérance orale est une des stratégies intéressantes pour prévenir les allergies alimentaires chez les enfants classés à risque. D’autre part, la composition de la microflore intestinale des enfants est un facteur important pour le développement de la tolérance. L’effet des bactéries probiotiques sur la tolérance orale a été très peu étudié et leurs mécanismes d’action sont mal documentés. Nous avons comparé l’effet de trois souches probiotiques sur l’induction et le maintien de la tolérance orale à la β-lactoglobuline chez la souris. Il a été observé que l’effet des probiotiques dépend de la souche utilisée et que la tolérance orale est bien induite et maintenue, aux niveaux humoral et cellulaire, en présence de Lactobacillus paracasei NCC2461. Les mécanismes d’action des probiotiques semblent être reliés à leur activité métabolique puisque des peptides issus de la β-lactoglobuline bovine, et libérés par L. paracasei ou Bifidobacterium lactis NCC362, modulent la réponse immune. Par contre, la stimulation de la voie de la cyclooxygénase-2 par les probiotiques n’a pas été observée, alors que l’implication de cette enzyme dans les mécanismes de la tolérance orale a clairement été démontrée.
Inducing oral tolerance to commonly allergenic food proteins is seen as a promising means to prevent food allergy in newborn population diagnosed as at risk of allergy. The intestinal microbiota has been shown to play a key role in oral tolerance development. Recently, a great interest has been focused on probiotic bacteria for their purported beneficial effects on human health but their effects on oral tolerance induction have been poorly investigated. The effect of three probiotic strains (Lactobacillus paracasei NCC2461, Lactobacillus johnsonii NCC533 and Bifidobacterium lactis NCC362) has been investigated and oral tolerance to bovine β-lactoglobulin (BLG) has been better induced and maintained in mice mono-colonized with L. paracasei. B. lactis and L. paracasei might induce oral tolerance through the hydrolysis of BLG and releasing of peptides with modified immunological properties. L. paracasei enzymes mainly hydrolyze acidic BLG-derived peptides and release smaller ones, which suppress splenocyte proliferation, down-regulate IFN-γ and IL-4 production and up-regulate IL-10 secretion. In contrast, hydrolysis of acidic BLG-derived peptides by B. lactis enzymes releases peptides, which stimulate splenocyte proliferation, IFN-γ and IL-10 production and down-regulate IL-4. Moreover, the residual allergenicity of released peptides is significantly reduced after B. lactis hydrolysis. These results suggest that L. paracasei and B. lactis might promote oral tolerance by activating different cellular mechanisms: L. paracasei stimulating the active suppression pathway, whereas B. lactis stimulating T helper type 1 lymphocytes downregulating T helper type 2 lymphocytes, implicated in allergy. On the other side, neither L. paracasei nor B. lactis was shown to stimulate the cyclooxygenase-2 pathway while its implication in oral tolerance induction has been clearly demonstrated.

Human milk is a complex fluid suspension of many ingredients — such as fats, proteins, lactose, and minerals — that differs greatly from bovine and other mammalian milks. The rheological properties of human milk impact its flow inside the breast and when fed through artificial feeding methods. Past research concerning the flow characteristics of human milk is extremely limited and does not account for milks non-Newtonian behavior. In order to produce an accurate model of milk flow in the human breast, experimental work was performed on human milk donated by eight mothers at different stages of lactogenesis II. The results of this small study reveal the complexity of human milk flow characteristics and the challenges involved with modeling its flow, especially at low shear rates. Within the human breast, shear rates vary greatly from as low as 12 s−1 to as high as 2.5 × 1016 s−1 depending on the ductal system geometry and flow rate. For researchers involved in experimentation, the environmental conditions, handling methods, and age of milk are extremely important and must be reported if the data is to be of any value. Further experimentation is required to fully understand the mechanisms behind the time-dependence behavior of human milk.

Sulfatides are sulfated glycolipids which are negatively charged and thought to influence receptor mediated activities. Sulfatides have the capacity to provide a surface for the initiation of in vitro coagulation tests and these acidic lipids represent the potential biological surface for the initiation of the contact and intrinsic systems in vivo. Several sulfatides have been demonstrated in blood platelets. We have investigated sulfatides and other glycolipids in endothelial cells and platelets in order to define the cellular sources for sulfatides that would be available for influencing hemostasis. Endothelial cells were derived from primary cultures of human umbilical veins and human platelets were obtained from freshly-collected blood. Cellular lipids were extracted by the Folch method. Sulfatides and glycolipids were purified by silicic acid chromatography, separated by thin-layer chromatography, and quantitated by the assay of sphingosine. Glycolipids were also analyzed by HPLC. Globoside was found to be the predominant glycolipid in endothelial cells while lactosyl ceramide was the predominant glyco-lipid in platelets. Sulfatides were detected by two approaches: 1) Sulfatide synthesis by the incorporation of [35S]-Sulfate; 2) The specific binding of [125I]-thrombospondin and [125I]-von Willebrand’s factor (vWF) to sulfatides separated by thin-layer chromatography (TLC). Several sulfatides were identified in endothelial cells and platelets by virtue of the incorporation of [35S]-sulfate into glycolipids separated by TLC. [125I]-TSP and [125I]-vWF bound to the glycolipids that had incorporated [35S]-sulfate. [35S]-sulfate was primarily incorporated into sulfated galactosyl ceramide but both cells also synthesized complex glycolipids. TSP and vWF were shown to bind to sulfated galactosyl ceramide, a band that comigrated with glycosyl ceramide as well as with two more complex sulfatides in both cells. However, differences in sulfatide synthesis and binding of TSP to sulfatides were observed in endothelial cells from that in platelets. The study indicates that endothelial cells and platelets contain several sulfatides and thus are potential sources for sulfatides for the initiation of coagulation.