130 research outputs found

    Green Production of Anionic Surfactant Obtained from Pea Protein

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    A pea protein isolate was hydrolyzed by a double enzyme treatment method in order to obtain short peptide sequences used as raw materials to produce lipopeptides-based surfactants. Pea protein hydrolysates were prepared using the combination of Alcalase and Flavourzyme. The influence of the process variables was studied to optimize the proteolytic degradation to high degrees of hydrolysis. The average peptide chain lengths were obtained at 3–5 amino acid units after a hydrolysis of 30 min with the mixture of enzymes. Then, N-acylation in water, in presence of acid chloride (C12 and C16), carried out with a conversion rate of amine functions of 90%, allowed to obtain anionic surfactant mixtures (lipopeptides and sodium fatty acids). These two steps were performed in water, in continuous and did not generate any waste. This process was therefore in line with green chemistry principles. The surface activities (CMC, foaming and emulsifying properties) of these mixtures were also studied. These formulations obtained from natural renewable resources and the reactions done under environmental respect, could replace petrochemical based surfactants for some applications

    Murine Leukemia Virus Spreading in Mice Impaired in the Biogenesis of Secretory Lysosomes and Ca2+-Regulated Exocytosis

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    Retroviruses have been observed to bud intracellularly into multivesicular bodies (MVB), in addition to the plasma membrane. Release from MVB is thought to occur by Ca(2+)-regulated fusion with the plasma membrane.To address the role of the MVB pathway in replication of the murine leukemia virus (MLV) we took advantage of mouse models for the Hermansky-Pudlak syndrome (HPS) and Griscelli syndrome. In humans, these disorders are characterized by hypopigmentation and immunological alterations that are caused by defects in the biogenesis and trafficking of MVBs and other lysosome related organelles. Neonatal mice for these disease models lacking functional AP-3, Rab27A and BLOC factors were infected with Moloney MLV and the spread of virus into bone marrow, spleen and thymus was monitored. We found a moderate reduction in MLV infection levels in most mutant mice, which differed by less than two-fold compared to wild-type mice. In vitro, MLV release form bone-marrow derived macrophages was slightly enhanced. Finally, we found no evidence for a Ca(2+)-regulated release pathway in vitro. Furthermore, MLV replication was only moderately affected in mice lacking Synaptotagmin VII, a Ca(2+)-sensor regulating lysosome fusion with the plasma membrane.Given that MLV spreading in mice depends on multiple rounds of replication even moderate reduction of virus release at the cellular level would accumulate and lead to a significant effect over time. Thus our in vivo and in vitro data collectively argue against an essential role for a MVB- and secretory lysosome-mediated pathway in the egress of MLV

    Identifying Human Disease Genes through Cross-Species Gene Mapping of Evolutionary Conserved Processes

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    Understanding complex networks that modulate development in humans is hampered by genetic and phenotypic heterogeneity within and between populations. Here we present a method that exploits natural variation in highly diverse mouse genetic reference panels in which genetic and environmental factors can be tightly controlled. The aim of our study is to test a cross-species genetic mapping strategy, which compares data of gene mapping in human patients with functional data obtained by QTL mapping in recombinant inbred mouse strains in order to prioritize human disease candidate genes.We exploit evolutionary conservation of developmental phenotypes to discover gene variants that influence brain development in humans. We studied corpus callosum volume in a recombinant inbred mouse panel (C57BL/6J×DBA/2J, BXD strains) using high-field strength MRI technology. We aligned mouse mapping results for this neuro-anatomical phenotype with genetic data from patients with abnormal corpus callosum (ACC) development.).This approach that exploits highly diverse mouse strains provides an efficient and effective translational bridge to study the etiology of human developmental disorders, such as autism and schizophrenia

    Identification and mutation analysis of the complete gene for Chediak-Higashi syndrome

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    Chediak-Higashi syndrome (CHS) is a rare, autosomal recessive disorder characterized by hypopigmentation, severe immunologic deficiency with neutropenia and lack of natural killer (NK) cells, a bleeding tendency and neurologic abnormalities1–4. Most patients die in childhood. The CHS hallmark is the occurrence of giant inclusion bodies and organelles in a variety of cell types, and protein sorting defects into these organelles5–8. Similar abnormalities occur in the beigemouse6,7,9–13, the proposed model for human CHS. Two groups have recently reported the identification of the beige gene14,15, however the two cDNAs were not at all similar. Here we describe the sequence of a human cDNA homologous to mouse beige, identify pathologic mutations and clarify the discrepancies of the previous reports. Analysis of the CHS polypeptide demonstrates that its modular architecture is similar to the yeast vacuolar sorting protein, VPS15

    The mouse pale ear pigment mutant as a possible animal model for human platelet storage pool deficiency

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    Abstract The mouse pigment mutant pale ear, ep/ep, which has a defect in kidney lysosomal enzyme secretion, had prolonged bleeding on experimental injury. Platelet counts and platelet protein did not differ from normal. There was, however, a deficiency in the platelet dense granule contents, serotonin, ATP, and ADP. Furthermore, a marked reduction of platelet dense granules was observed by electron microscopy. The results suggest that pale ear is a useful animal model in the study of platelet storage pool disease. Studies on this mutant and other pigment mutants have established that one gene can regulate at least three subcellular organelles, including the melanosome, the lysosome, and the platelet dense granule.</jats:p

    Platelet storage pool deficiency in mouse pigment mutations associated with seven distinct genetic loci

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    Abstract Seven mouse pigment mutants, which have alterations at distinct genes, are known to have a defect in kidney lysosomal enzyme secretion. Two of these, beige and pale ear, have a bleeding abnormality associated with a deficiency in the number of platelet dense granules. In the present study, five other mutants with defective lysosomal enzyme secretion-- pearl, pallid, light ear, maroon, and ruby-eye--were likewise found to have abnormally prolonged bleeding times after experimental injury. Platelet counts were similar to those of normal mice, but the platelet dense granule components serotonin, adenosine triphosphate (ATP), and adenosine diphosphate (ADP) and morphologically identifiable dense granules were markedly reduced in these mutants. The capacity to accumulate exogenous 3H-serotonin in platelets was reduced 2–3-fold. Thrombin-stimulated secretion of 3H-serotonin was slightly decreased in all mutants. However, the seven mutants could be subdivided into three groups based on the degree of secretion of lysosomal enzymes after thrombin stimulation. Thus, all seven mouse pigment mutants have symptoms consistent with platelet storage pool deficiency and may serve as useful animal models for specific types of human platelet storage pool disease. Also, the results emphasize the genetic, morphological, and functional interrelatedness of three organelles: melanosomes, lysosomes, and platelet dense granules.</jats:p

    Correction of symptoms of platelet storage pool deficiency in animal models for Chediak-Higashi syndrome and Hermansky-Pudlak syndrome

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    Abstract Two human diseases of platelet storage pool deficiency (SPD), Hermansky- Pudlak syndrome and Chediak-Higashi syndrome, are recessively inherited disorders characterized by hypopigmentation, prolonged bleeding, and normal platelet counts accompanied by a reduction in dense granule number. We have recently described seven independent recessive mutations in the mouse regulated by separate genes which are likely animal models for human SPD. Reciprocal bone marrow transplants were carried out between normal C57BL/6J mice and two of these mutants, beige and pallid, in order to test whether the platelet defects are due to a defect in platelet progenitor cells or to humoral factors. Normal and congenic mutant mice were transplanted with marrow after 950 rad whole body radiation. The long bleeding times and low serotonin concentrations of the two mutants were converted to normal values after transplantation with normal marrow. Likewise, normal mice displayed symptoms of SPD when transplanted with mutant marrow. These studies demonstrate that with each of the two mutations, platelet SPD results from a defect in bone marrow precursor cells. Also, the studies suggest that in severe cases, platelet SPD may be successfully treated by bone marrow transplantation.</jats:p
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