509 research outputs found

    Tomato juices and tomato juice concentrates : a study of factors contributing to their gross viscosity

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    The gross viscosity of tomato juice and tomato juice concentrates was found to be determined primarily by the water insoluble solids (WIS) content. The serum viscosity did not contribute to gross viscosity. The WIS consisted of whole tomato cells, vascular bundles and skin fragments. In general the WIS could be fractionated into 40-45% pectin, 25-30% hemicellulose and 30-35% cellulose. Highly branched as well as more linear pectin fragments were found to be present in tomato WIS. Xylans, arabinans and (arabino)galactans were involved in the attachment of pectic substances to the cell wall matrix. The presence of xylans, xyloglucans, (gluco)mannans and a limited amount of galactan in the hemicellulose was indicated. Pectin fragments, characterized by a low content of arabinose and galactose containing side chains, and esterified in such a way that they were degraded by both PG and PL, made an important contribution to gross viscosity. Cellulose was found to make a relatively smaller contribution to gross viscosity than these pectin fragments. The rigidity of the cell walls, caused by the cellulosic structure, seemed to influence gross viscosity at higher WIS concentrations. The differences which exist naturally in WIS composition were found to be too small to cause large differences In gross viscosity. Higher hot break temperatures were found to result in a more effective removal of WIS from skin material. The influences of hot break temperature, finisher temperature and size of finisher screen opening on the finisher operation were closely related to the efficiency of the finisher. The concentration of a tomato juice by evaporation resulted in a loss in gross viscosity, after dilution of the paste to the original strength. The causes for this "dilution-loss" were studied and could be related to the simultaneous concentration of tomato cells and, presumably, ions. The centrifugation-serum-concentration method resulted in a significantly decreased "dilution-loss".</TT

    DJ-1 transcriptionally up-regulates the human tyrosine hydroxylase by inhibiting the sumoylation of pyrimidine tract-binding protein-associated splicing factor.

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    Loss-of-function mutations in DJ-1 cause a subset of familial Parkinson disease (PD). However, the mechanism underlying the selective vulnerability in dopaminergic pathway due to the inactivation of DJ-1 is unclear. Previously, we have reported that DJ-1 is a neuroprotective transcriptional co-activator interacting with the transcriptional co-repressor pyrimidine tract-binding protein-associated splicing factor (PSF). Here we show that DJ-1 and PSF bind and regulate the human tyrosine hydroxylase (TH) promoter. Inactivation of DJ-1 by small interference RNA (siRNA) results in decreased TH expression and l-DOPA production in human dopaminergic cell lines. Consistent with its role as a transcriptional regulator, DJ-1 specifically suppresses the global SUMO-1 modification. High molecular weight sumoylated protein species, including PSF, accumulate in the lymphoblast cells from the patients carrying pathogenic DJ-1 mutations. DJ-1 elevates the TH expression by inhibiting the sumoylation of PSF and preventing its sumoylation-dependent recruitment of histone deacetylase 1. Furthermore, siRNA silencing of DJ-1 decreases the acetylation of TH promoter-bound histones, and histone deacetylase inhibitors restore the DJ-1 siRNA-induced repression of TH. Therefore, our results suggest DJ-1 as a regulator of protein sumoylation and directly link the loss of DJ-1 expression and transcriptional dysfunction to impaired dopamine synthesis

    Genetic analysis identifies potential transmission of low pathogenic avian influenza viruses between poultry farms

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    Poultry can become infected with low pathogenic avian influenza (LPAI) viruses via (in)direct contact with infected wild birds or by transmission of the virus between farms. This study combines routinely collected surveillance data with genetic analysis to assess the contribution of between-farm transmission to the overall incidence of LPAI virus infections in poultry. Over a 10-year surveillance period, we identified 35 potential cases of between-farm transmission in the Netherlands, of which 10 formed geographical clusters. A total of 21 LPAI viruses were isolated from nine potential between-farm transmission cases, which were further studied by genetic and epidemiological analysis. Whole genome sequence analysis identified close genetic links between infected farms in seven cases. The presence of identical deletions in the neuraminidase stalk region and minority variants provided additional indications of between-farm transmission. Spatiotemporal analysis demonstrated that genetically closely related viruses were detected within a median time interval of 8 days, and the median distance between the infected farms was significantly shorter compared to farms infected with genetically distinct viruses (6.3 versus 69.0 km; p < 0.05). The results further suggest that between-farm transmission was not restricted to holdings of the same poultry type and not related to the housing system. Although separate introductions from the wild bird reservoir cannot be excluded, our study indicates that between-farm transmission occurred in seven of nine virologically analysed cases. Based on these findings, it is likely that between-farm transmission contributes considerably to the incidence of LPAI virus infections in poultry

    Mutation Frequency of the Major Frontotemporal Dementia Genes, MAPT, GRN and C9ORF72 in a Turkish Cohort of Dementia Patients

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    ‘Microtubule-associated protein tau’ (MAPT), ‘granulin’ (GRN) and ‘chromosome 9 open reading frame72’ (C9ORF72) gene mutations are the major known genetic causes of frontotemporal dementia (FTD). Recent studies suggest that mutations in these genes may also be associated with other forms of dementia. Therefore we investigated whether MAPT, GRN and C9ORF72 gene mutations are major contributors to dementia in a random, unselected Turkish cohort of dementia patients. A combination of whole-exome sequencing, Sanger sequencing and fragment analysis/Southern blot was performed in order to identify pathogenic mutations and novel variants in these genes as well as other FTD-related genes such as the ‘charged multivesicular body protein 2B’ (CHMP2B), the ‘FUS RNA binding protein’ (FUS), the ‘TAR DNA binding protein’ (TARDBP), the ‘sequestosome1’ (SQSTM1), and the ‘valosin containing protein’ (VCP). We determined one pathogenic MAPT mutation (c.1906C>T, p.P636L) and one novel missense variant (c.38A>G, p.D13G). In GRN we identified a probably pathogenic TGAG deletion in the splice donor site of exon 6. Three patients were found to carry the GGGGCC expansions in the non-coding region of the C9ORF72 gene. In summary, a complete screening for mutations in MAPT, GRN and C9ORF72 genes revealed a frequency of 5.4% of pathogenic mutations in a random cohort of 93 Turkish index patients with dementia

    High prevalence of mutations in the microtubule-associated protein tau in a population study of frontotemporal dementia in the Netherlands

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    Mutations in microtubule-associated protein tau recently have been identified in familial cases of frontotemporal dementia (FTD). We report the frequency of tau mutations in a large population-based study of FTD carried out in the Netherlands from January 1994 to June 1998. Thirty-seven patients had >/=1 first-degree relative with dementia. A mutation in the tau gene was found in 17.8% of the group of patie

    Establishing the role of rare coding variants in known Parkinson's disease risk loci

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    Many common genetic factors have been identified to contribute to Parkinson's disease (PD) susceptibility, improving our understanding of the related underlying biological mechanisms. The involvement of rarer variants in these loci has been poorly studied. Using International Parkinson's Disease Genomics Consortium data sets, we performed a comprehensive study to determine the impact of rare variants in 23 previously published genome-wide association studies (GWAS) loci in PD. We applied Prix fixe to select the putative causal genes underneath the GWAS peaks, which was based on underlying functional similarities. The Sequence Kernel Association Test was used to analyze the joint effect of rare, common, or both types of variants on PD susceptibility. All genes were tested simultaneously as a gene set and each gene individually. We observed a moderate association of common variants, confirming the involvement of the known PD risk loci within our genetic data sets. Focusing on rare variants, we identified additional association signals for LRRK2, STBD1, and SPATA19. Our study suggests an involvement of rare variants within several putatively causal genes underneath previously identified PD GWAS peaks

    Clinicoradiological manifestations of paraganglioma syndromes associated with succinyl dehydrogenase enzyme mutation

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    BACKGROUND: Paragangliomas are rare tumours derived from the autonomic nervous system that have increasingly been recognised to have a genetic predisposition. Mutations of the enzyme succinyl dehydrogenase (SDH) have proven to result in paraganglioma formation. There are four subunits (A through D) that form the enzyme complex and are associated with different genophenotypic expressions of disease. SDHB and SDHD mutations are more common, whereas SDHA and SDHC mutations are rare. Patients with SDHB mutations are prone to extra-adrenal pheochromocytomas, malignant disease and extra-paraganglial neoplasia, whereas SDHD mutations have a greater propensity for multiple, benign head and neck paragangliomas. METHODS: Diagnosis of a sporadic paraganglioma or pheochromocytoma should lead to a full genetic workup of the patient and family if SDH mutations are found. RESULTS: Further annual screening will be required depending on the mutation, which can have a significant impact on radiologists and the resources of the radiology department. CONCLUSION: We present our imaging experience with a series of patients with proven SDH mutations resulting in paragangliomas with a review of the literature

    Association between the CHRM2 gene and intelligence in a sample of 304 Dutch families.

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    The CHRM2 gene is thought to be involved in neuronal excitability, synaptic plasticity and feedback regulation of acetylcholine release and has previously been implicated in higher cognitive processing. In a sample of 667 individuals from 304 families, we genotyped three singlenucleotide polymorphisms (SNPs) in the CHRM2 gene on 7q31–35. From all individuals, standardized intelligence measures were available. Using a test of within-family association, which controls for the possible effects of population stratification, a highly significant association was found between the CHRM2 gene and intelligence. The strongest association was between rs324650 and performance IQ (PIQ), where the T allele was associated with an increase of 4.6 PIQ points. In parallel with a large familybased association, we observed an attenuated – although still significant – population-based association, illustrating that population stratification may decrease our chances of detecting allele–trait associations. Such a mechanism has been predicted earlier, and this article is one of the first to empirically show that family-based association methods are not only needed to guard against false positives, but are also invaluable in guarding against false negatives

    Extended Haplotypes in the Growth Hormone Releasing Hormone Receptor Gene (GHRHR) Are Associated with Normal Variation in Height

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    Mutations in the gene for growth hormone releasing hormone receptor (GHRHR) cause isolated growth hormone deficiency (IGHD) but this gene has not been found to affect normal variation in height. We performed a whole genome linkage analysis for height in a population from northern Sweden and identified a region on chromosome 7 with a lod-score of 4.7. The GHRHR gene is located in this region and typing of tagSNPs identified a haplotype that is associated with height (p = 0.00077) in the original study population. Analysis of a sample from an independent population from the most northern part of Sweden also showed an association with height (p = 0.0039) but with another haplotype in the GHRHR gene. Both haplotypes span the 3′ part of the GHRHR gene, including the region in which most of the mutations in IGHD have been located. The effect size of these haplotypes are larger than that of any gene previously associated with height, which indicates that GHRHR might be one of the most important genes so far identified affecting normal variation in human height
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