Exocytosis in Type 2 Diabetes- Functional and genetic studies of hormone secretion

Type 2 Diabetes (T2D) is characterized by dysregulated beta-and alpha-cell hormone secretion leading to elevated blood glucose levels. Several proteins are crucial in maintaining exocytosis of the hormone-containing granules such as Syntaxin1A (Stx1A), SNAP25, Munc-18 (Stxbp1) and the family of Synaptotagmins (Syts). The aim of this thesis has been to investigate functional and genetic events that participate in the exocytotic process. First we show that SNAP25 is essential for cAMP-dependent rapid exocytosis in insulin-secreting cells, and that the effect may be mediated by binding to cAMP-GEFII (paper I). In mouse alpha-cells, SNAP25 and Stx1A display a glucose-dependent localization where immunoneutralization of SNAP25 and Stx1A strongly reduce the exocytotic response (paper II). In paper III, the mRNA expression levels of 23 genes with known function in exocytosis was compared in human beta-cells from non-diabetic (ND) and T2D donors which revealed that STX1A, SYT4, SYT7, SYT11 and SYT13 is nominally down-regulated in T2D beta-cells and concomitantly correlate positively with glucose stimulated insulin secretion (GSIS) and negatively with HbA1c levels. Furthermore, silencing of Syt4, Syt7 and Syt13 in INS1-832/13 cells correlate with reduced levels of GSIS. In paper IV exocytosis in human beta-cells was studied to generate a risk score consisting of 4 SNPs in or near TCF7L2, KCNJ11, ADRA2A and KCNQ1 that successfully predict reduced exocytosis, calcium-sensitivity, granular docking and GSIS. Finally, in paper V, knock-down of rno-microRNA-335 in insulin-secreting cells was found to increase Stxbp1 expression which correlates with increased exocytosis. Within the scope of this thesis we establish that exocytosis is an important part of glucose homeostasis and that a broad range of factors can influence the exocytotic outcome. In this context, regulation of exocytosis span from the transcription of DNA, translation, transport and function of exocytotic proteins as well as their intricate interactions with one another. All while maintaining the correct cues in response to increased levels of intracellular calcium either amplified by second messengers or triggered by glucose-stimulated coupling. Taken together, extensive research on the molecular mechanisms participating in hormone exocytosis may well contribute to future treatment of the reduced insulin secretion apparent in T2D

Bedding material properties and slurry C/N ratio affect the availability of nitrogen in cattle slurry applied to soil

IntroductionCattle slurry used as fertilizer in crop production is a mix of feces, urine, water, and bedding material from the housing system. Previous studies have shown that slurry nitrogen (N) availability to crops is dependent on C/N ratio. As the bedding material can contribute a significant part of total slurry carbon (C), its characteristics may affect the C/N ratio of the slurry. There is increasing interest in using the solid fraction from mechanical slurry separation as bedding material, and therefore this study investigated the potential effect of this fraction on slurry N availability, compared with more commonly used bedding materials such as straw and sawdust.MethodsIn two parallel 28-day laboratory incubations, net mineral N release and C mineralization from slurries applied to sandy loam soil were measured. The slurries comprised a liquid fraction (LF) from mechanical cattle slurry separation with a screw-press and different added bedding materials. Liquid fraction was mixed with two types of bedding material, solid slurry fraction (SF) and chopped straw, in different proportions, resulting in C/N ratios of 10, 12, and 14 in the slurry. In additional treatments, two other bedding materials, ground straw and sawdust, with slurry C/N ratio 12, were used.ResultsFor SF and chopped straw, similar negative linear correlations were seen between slurry C/N ratio and net mineral N release after 28 days. Carbon mineralization, expressed as a percentage of total C added, was higher from the mixture containing SF than that containing straw, while no clear relationship with C/N ratio was found. At slurry C/N ratio 12, net release of mineral N was 28–39% of total N and decreased in the order: sawdust>chopped straw=SF=ground straw. Net C mineralization at the same slurry C/N ratio was 33–46% and decreased in the order: SF=ground straw>chopped straw>sawdust.DiscussionFor bedding materials with similar fiber composition (i.e., SF and straw), differences in C availability due to particle size or degree of degradation by microorganisms did not influence slurry N availability measurably. For sawdust, with high lignin content, the results indicate that limited C availability may lead to lower slurry N immobilization

Genomic relatedness and diversity of Swedish native cattle breeds

International audienceAbstractBackgroundNative cattle breeds are important genetic resources given their adaptation to the local environment in which they are bred. However, the widespread use of commercial cattle breeds has resulted in a marked reduction in population size of several native cattle breeds worldwide. Therefore, conservation management of native cattle breeds requires urgent attention to avoid their extinction. To this end, we genotyped nine Swedish native cattle breeds with genome-wide 150 K single nucleotide polymorphisms (SNPs) to investigate the level of genetic diversity and relatedness between these breeds.ResultsWe used various SNP-based approaches on this dataset to connect the demographic history with the genetic diversity and population structure of these Swedish cattle breeds. Our results suggest that the Väne and Ringamåla breeds originating from southern Sweden have experienced population isolation and have a low genetic diversity, whereas the Fjäll breed has a large founder population and a relatively high genetic diversity. Based on the shared ancestry and the constructed phylogenetic trees, we identified two major clusters in Swedish native cattle. In the first cluster, which includes Swedish mountain cattle breeds, there was little differentiation among the Fjäll, Fjällnära, Swedish Polled, and Bohus Polled breeds. The second cluster consists of breeds from southern Sweden: Väne, Ringamåla and Swedish Red. Interestingly, we also identified sub-structuring in the Fjällnära breed, which indicates different breeding practices on the farms that maintain this breed.ConclusionsThis study represents the first comprehensive genome-wide analysis of the genetic relatedness and diversity in Swedish native cattle breeds. Our results show that different demographic patterns such as genetic isolation and cross-breeding have shaped the genomic diversity of Swedish native cattle breeds and that the Swedish mountain breeds have retained their authentic distinct gene pool without significant contribution from any of the other European cattle breeds that were included in this study

HIV/AIDS awareness and risk behaviour among pregnant women in Semey, Kazakhstan, 2007

<p>Abstract</p> <p>Background</p> <p>Central Asia has one of the most rapidly increasing HIV prevalence in the world. The aim of this study was to evaluate current knowledge, risk behaviour and attitudes to voluntary counselling and testing concerning HIV/AIDS among pregnant women in Semey, Kazakhstan.</p> <p>Methods</p> <p>We collected 226 questionnaires in a consecutive sample from a population on 520 pregnant women. The results were related to ethnicity, age and education level.</p> <p>Results</p> <p>Ninety-six percent had heard about HIV.</p> <p>Positive findings were that 89% and 86% of the women were aware of the two main routes of transmission: sexual intercourses without a condom and sharing needles while injecting drugs. The women had first heard about HIV/AIDS through the media with, 52%, and at school with 40%. Only 46% and 68% of the women pointed out breastfeeding and mother-to-child transmission during pregnancy or delivery as routes of transmission. Eighty-three percent were prepared not to breastfeed their baby if they were found to be HIV positive. Slightly more, 86%, accepted the need to take medicine, but fewer women, 68%, were positive to Caesarean section. Negative findings were that only 28% answered that there are ways to protect oneself against sexually transmitted HIV/AIDS and specified that this was condom use.</p> <p>Conclusion</p> <p>The pregnant women in Semey have poor knowledge about specific mother-to-child HIV transmission and do not know about the means of reducing mother-to-child HIV infection. The information in the public health program needs to be improved. However, most of the women in Semey were positive to prevention strategies for mother-to-child transmission after hearing about it.</p

Treatment in the context of confinement: – understanding the barriers and possibilities for facilitating change in at-risk youth

AbstractIn this article the authors present a meta-synthesis of their studies on secure institutions in Sweden and Denmark. The aim of the metasynthesis is to explore how the context of confinement shapes the possibilities for providing treatment and positive change for at-risk youth. Drawing on meta-synthesis methodology the authors extract content from nine studies published in 20 articles. We highlight three dimensions, which are a) treatment practices and behavioural regulation, b) the carceral materialities and sociomaterial practices, and c) relations. We argue that while treatment is curtailed by confinement, improvements can be made to support more successful change among at-risk youth and smooth their transition into adulthood. Artiklen præsenterer en metasyntese af ni studier om sikrede institutioner i Danmark og Sverige. Formålet med metasyntesen er at undersøge, hvordan frihedsberøvelse rammesætter behandling og forandringsarbejde med unge i udsatte positioner. Forfatterne analyserer 20 artikler fordelt på ni studier, de selv har gennemført. Analysen har fokus på tre centrale forhold; a) behandlingsarbejde og adfærdsregulering, b) materialitet og sociomaterielle praktikker, og c) relationer. Vi argumenterer for, at behandling påvirkes af frihedsberøvelse, men med forbedringer kan behandling på sikret institution bidrage til at skabe positiv forandring og sikre de unges overgang til voksenliv

Reduced insulin secretion correlates with decreased expression of exocytotic genes in pancreatic islets from patients with type 2 diabetes.

Reduced insulin release has been linked to defect exocytosis in β-cells. However, whether expression of genes suggested to be involved in the exocytotic process (exocytotic genes) is altered in pancreatic islets from patients with type 2 diabetes (T2D), and correlate to insulin secretion, needs to be further investigated. Analysing expression levels of 23 exocytotic genes using microarray revealed reduced expression of five genes in human T2D islets (χ(2)=13.25; p<0.001). Gene expression of STX1A, SYT4, SYT7, SYT11, SYT13, SNAP25 and STXBP1 correlated negatively to in vivo measurements of HbA1c levels and positively to glucose stimulated insulin secretion (GSIS) in vitro in human islets. STX1A, SYT4 and SYT11 protein levels correspondingly decreased in human T2D islets. Moreover, silencing of SYT4 and SYT13 reduced GSIS in INS1-832/13 cells. Our data support that reduced expression of exocytotic genes contributes to impaired insulin secretion, and suggest decreased expression of these genes as part of T2D pathogenesis

Targeted analysis of four breeds narrows equine Multiple Congenital Ocular Anomalies locus to 208 kilobases

The syndrome Multiple Congenital Ocular Anomalies (MCOA) is the collective name ascribed to heritable congenital eye defects in horses. Individuals homozygous for the disease allele (MCOA phenotype) have a wide range of eye anomalies, while heterozygous horses (Cyst phenotype) predominantly have cysts that originate from the temporal ciliary body, iris, and/or peripheral retina. MCOA syndrome is highly prevalent in the Rocky Mountain Horse but the disease is not limited to this breed. Affected horses most often have a Silver coat color; however, a pleiotropic link between these phenotypes is yet to be proven. Locating and possibly isolating these traits would provide invaluable knowledge to scientists and breeders. This would favor maintenance of a desirable coat color while addressing the health concerns of the affected breeds, and would also provide insight into the genetic basis of the disease. Identical-by-descent mapping was used to narrow the previous 4.6-Mb region to a 264-kb interval for the MCOA locus. One haplotype common to four breeds showed complete association to the disease (Cyst phenotype, n = 246; MCOA phenotype, n = 83). Candidate genes from the interval, SMARCC2 and IKZF4, were screened for polymorphisms and genotyped, and segregation analysis allowed the MCOA syndrome region to be shortened to 208 kb. This interval also harbors PMEL17, the gene causative for Silver coat color. However, by shortening the MCOA locus by a factor of 20, 176 other genes have been unlinked from the disease and only 15 genes remain

On the Origin of Indonesian Cattle

Background: Two bovine species contribute to the Indonesian livestock, zebu (Bos indicus) and banteng (Bos javanicus), respectively. Although male hybrid offspring of these species is not fertile, Indonesian cattle breeds are supposed to be of mixed species origin. However, this has not been documented and is so far only supported by preliminary molecular analysis. Methods and Findings: Analysis of mitochondrial, Y-chromosomal and microsatellite DNA showed a banteng introgression of 10-16% in Indonesian zebu breeds. East-Javanese Madura and Galekan cattle have higher levels of autosomal banteng introgression (20-30%) and combine a zebu paternal lineage with a predominant (Madura) or even complete (Galekan) maternal banteng origin. Two Madura bulls carried taurine Y-chromosomal haplotypes, presumably of French Limousin origin. In contrast, we did not find evidence for zebu introgression in five populations of the Bali cattle, a domestic form of the banteng. Conclusions: Because of their unique species composition Indonesian cattle represent a valuable genetic resource, which potentially may also be exploited in other tropical regions. © 2009 Mohamad et al

The same ELA class II risk factors confer equine insect bite hypersensitivity in two distinct populations

Insect bite hypersensitivity (IBH) is a chronic allergic dermatitis common in horses. Affected horses mainly react against antigens present in the saliva from the biting midges, Culicoides ssp, and occasionally black flies, Simulium ssp. Because of this insect dependency, the disease is clearly seasonal and prevalence varies between geographical locations. For two distinct horse breeds, we genotyped four microsatellite markers positioned within the MHC class II region and sequenced the highly polymorphic exons two from DRA and DRB3, respectively. Initially, 94 IBH-affected and 93 unaffected Swedish born Icelandic horses were tested for genetic association. These horses had previously been genotyped on the Illumina Equine SNP50 BeadChip, which made it possible to ensure that our study did not suffer from the effects of stratification. The second population consisted of 106 unaffected and 80 IBH-affected Exmoor ponies. We show that variants in the MHC class II region are associated with disease susceptibility (praw = 2.34 × 10−5), with the same allele (COR112:274) associated in two separate populations. In addition, we combined microsatellite and sequencing data in order to investigate the pattern of homozygosity and show that homozygosity across the entire MHC class II region is associated with a higher risk of developing IBH (p = 0.0013). To our knowledge this is the first time in any atopic dermatitis suffering species, including man, where the same risk allele has been identified in two distinct populations

Genetic diversity in the modern horse illustrated from genome-wide SNP data

Horses were domesticated from the Eurasian steppes 5,000-6,000 years ago. Since then, the use of horses for transportation, warfare, and agriculture, as well as selection for desired traits and fitness, has resulted in diverse populations distributed across the world, many of which have become or are in the process of becoming formally organized into closed, breeding populations (breeds). This report describes the use of a genome-wide set of autosomal SNPs and 814 horses from 36 breeds to provide the first detailed description of equine breed diversity. F(ST) calculations, parsimony, and distance analysis demonstrated relationships among the breeds that largely reflect geographic origins and known breed histories. Low levels of population divergence were observed between breeds that are relatively early on in the process of breed development, and between those with high levels of within-breed diversity, whether due to large population size, ongoing outcrossing, or large within-breed phenotypic diversity. Populations with low within-breed diversity included those which have experienced population bottlenecks, have been under intense selective pressure, or are closed populations with long breed histories. These results provide new insights into the relationships among and the diversity within breeds of horses. In addition these results will facilitate future genome-wide association studies and investigations into genomic targets of selection