Hur simträning påverkar hundar

Hydrotherapy is a relatively new area when it comes to treatment and prevention of different problems in dogs, but an area that is growing in popularity. In Sweden, the person who performs hydrotherapy on dogs doesn’t need veterinary education, which is the case in some other countries. What makes hydrotherapy advantageous is that water has an ability to provide an environment where injured body parts can be supported, which means that rehabilitation can start early without the risk of affecting the injury and in the same time relieve the pain for the patient. There are only a few studies of hydrotherapy on dogs and these studies focus on the physical health of the dog. For instance there are studies that show that hydrotherapy can improve joint function in dogs with cranial cruciate ligament rupture. Studies of hydrotherapy on humans are more common and show that hydrotherapy for instance can be beneficial on osteoarthritis and fibromyalgia. From an ethological- and animal welfare point of view it is important to see how dogs feel in the situation of hydrotherapy both by studying their physical health and their behaviour. Often these two parts depend on each other but not always, because dogs often hide their pain. The aim of this thesis was to investigate how dogs are affected both during and after hydrotherapy, from an ethological- and animal welfare point of view. The focus of this study has not only been on the physical health of the dogs but also on how their behaviour is affected and the purpose was to get the owners own experiences of this. To get the owners experiences of how dogs are affected by hydrotherapy, inquiries were sent out to clients at a rehabilitation centre which provides hydrotherapy for dogs. The result of this was that 31 replies could be used in this study. Questions were asked about the background of the dog and experiences of how the dog has been affected by hydrotherapy in different circumstances. This study shows that hydrotherapy can have a positive effect on the physical health of dogs and on their behaviour, which is shown in the owners’ experiences of their dogs having more strength in their daily life and being mor positive, in comparison with how they were before the hydrotherapy began. Hydrotherapy also seems to have a pain relieving effect, which in turn seems to have a positive effect on the temperament of the dogs. Many dog owners experience a positive change in their dog’s temperament, despite the fact that they experienced the dog to normally be very playful. If this is because the dog have been hiding it’s pain is hard to interpret, but it does show the importance of studying both the physical health and the behaviour of the dog. The fact that pain can be reduced and that more fortitude of the dogs increase the opportunities for them to be stimulated in their daily life indicate that hydrotherapy can improve quality of life for dogs. Complications or problems due to hydrotherapy doesn’t seem to be common for the dogs in this study. From an ethological- and animal welfare point of view this study shows that if consideration is taken to how the dog is affected by hydrotherapy, hydrotherapy can be said to be beneficial for dogs

A highly conserved segmental duplication in the subtelomeres of Plasmodium falciparum chromosomes varies in copy number

<p>Abstract</p> <p>Background</p> <p>Segmental duplications (SD) have been found in genomes of various organisms, often accumulated at the ends of chromosomes. It has been assumed that the sequence homology in-between the SDs allow for ectopic interactions that may contribute to the emergence of new genes or gene variants through recombinatorial events.</p> <p>Methods</p> <p><it>In silico </it>analysis of the 3D7 <it>Plasmodium falciparum </it>genome, conducted to investigate the subtelomeric compartments, led to the identification of subtelomeric SDs. Sequence variation and copy number polymorphisms of the SDs were studied by DNA sequencing, real-time quantitative PCR (qPCR) and fluorescent <it>in situ </it>hybridization (FISH). The levels of transcription and the developmental expression of copy number variant genes were investigated by qPCR.</p> <p>Results</p> <p>A block of six genes of >10 kilobases in size, including <it>var</it>, <it>rif</it>, <it>pfmc-2tm </it>and three hypothetical genes (<it>n-, o- </it>and <it>q-gene</it>), was found duplicated in the subtelomeric regions of chromosomes 1, 2, 3, 6, 7, 10 and 11 (SD1). The number of SD1 per genome was found to vary from 4 to 8 copies in between different parasites. The intragenic regions of SD1 were found to be highly conserved across ten distinct fresh and long-term cultivated <it>P. falciparum</it>. Sequence variation was detected in a ≈ 23 amino-acid long hypervariable region of a surface-exposed loop of PFMC-2TM. A hypothetical gene within SD1, the <it>n-gene</it>, encoding a PEXEL/VTS-containing two-transmembrane protein was found expressed in ring stage parasites. The <it>n-gene </it>transcription levels were found to correlate to the number of <it>n-gene </it>copies. Fragments of SD1 harbouring two or three of the SD1-genes (<it>o-gene, pfmc-2tm, q-gene</it>) were also found in the 3D7 genome. In addition a related second SD, SD2, of ≈ 55% sequence identity to SD1 was found duplicated in a fresh clinical isolate but was only present in a single copy in 3D7 and in other <it>P. falciparum </it>lines or clones.</p> <p>Conclusion</p> <p><it>Plasmodium falciparum </it>carries multiple sequence conserved SDs in the otherwise highly variable subtelomeres of its chromosomes. The uniqueness of the SDs amongst plasmodium species, and the conserved nature of the genes within, is intriguing and suggests an important role of the SD to <it>P. falciparum</it>.</p

SURFIN4.1, a schizont-merozoite associated protein in the SURFIN family of Plasmodium falciparum

<p>Abstract</p> <p>Background</p> <p>In its effort to survive the human immune system, <it>Plasmodium falciparum </it>uses several parasite-derived antigens most of which are expressed at the surface of the parasitized red blood cells (pRBCs). Recently SURFINs, a new family of antigens encoded by the <it>surf </it>multi-gene family, has been reported. One member of the family, SURFIN_4.2, was found present both at the pRBC-surface and at the merozoite apex.</p> <p>Methods</p> <p>The presence of a second SURFIN member, SURFIN_4.1(PFD0100c, PFD0105c) is reported here. Bioinformatic tools were used to study the structure of the <it>surf</it>_4.1gene. To investigate the expression of <it>surf </it>genes PCR and real-time quantitative PCR (Rt-QPCR) were employed and Northern and Western blots were used to confirm the size of the <it>surf</it>_4.1gene and the SURFIN_4.1protein respectively. Localization of SURFIN_4.1was determined using immunofluorescence assays.</p> <p>Results</p> <p>The <it>surf</it>_4.1gene was found present in one copy by Rt-QPCR in some parasites (3D7AH1, 3D7S8, 7G8) whereas six copies of the gene were identified in FCR3 and FCR3S1.2. <it>surf</it>_4.1was found transcribed in the late asexual stages of the parasite beginning ≈32 hours post invasion and throughout the schizont stages with the level of transcription peaking at late schizogony. The levels of transcript correlated with the number of gene copies in FCR3 and 3D7S8. <it>surf</it>_4.1was found to encode a polypeptide of ≈Mw 258 kDa (SURFIN_4.1) present within the parasitophorous vacuole (PV), around free merozoites as merozoite-associated material, but not at the pRBC-surface. Despite multiple <it>surf</it>_4.1gene copies in some parasites this was not reflected in the levels of SURFIN_4.1polypeptide.</p> <p>Conclusion</p> <p>SURFIN_4.1is a member of the SURFINs, present in the PV and on the released merozoite. The results suggest different SURFINs to be expressed at different locations in the parasite and at distinct time-points during the intra-erythrocytic cycle.</p

Simultaneous transcription of duplicated var2csa gene copies in individual Plasmodium falciparum parasites

Duplicated var2csa genes in one strain of Plasmodium falciparum are simultaneously transcribed, challenging the dogma of mutual exclusive var gene transcriptio

A global transcriptional analysis of Plasmodium falciparum malaria reveals a novel family of telomere-associated lncRNAs

Background: Mounting evidence suggests a major role for epigenetic feedback in Plasmodium falciparum transcriptional regulation. Long non-coding RNAs (lncRNAs) have recently emerged as a new paradigm in epigenetic remodeling. We therefore set out to investigate putative roles for lncRNAs in P. falciparum transcriptional regulation. Results: We used a high-resolution DNA tiling microarray to survey transcriptional activity across 22.6% of the P. falciparum strain 3D7 genome. We identified 872 protein-coding genes and 60 putative P. falciparum lncRNAs under developmental regulation during the parasite's pathogenic human blood stage. Further characterization of lncRNA candidates led to the discovery of an intriguing family of lncRNA telomere-associated repetitive element transcripts, termed lncRNA-TARE. We have quantified lncRNA-TARE expression at 15 distinct chromosome ends and mapped putative transcriptional start and termination sites of lncRNA-TARE loci. Remarkably, we observed coordinated and stage-specific expression of lncRNA-TARE on all chromosome ends tested, and two dominant transcripts of approximately 1.5 kb and 3.1 kb transcribed towards the telomere. Conclusions: We have characterized a family of 22 telomere-associated lncRNAs in P. falciparum. Homologous lncRNA-TARE loci are coordinately expressed after parasite DNA replication, and are poised to play an important role in P. falciparum telomere maintenance, virulence gene regulation, and potentially other processes of parasite chromosome end biology. Further study of lncRNA-TARE and other promising lncRNA candidates may provide mechanistic insight into P. falciparum transcriptional regulation.Organismic and Evolutionary BiologyStem Cell and Regenerative BiologyOther Research Uni

A genomic and evolutionary approach reveals non-genetic drug resistance in malaria

Background: Drug resistance remains a major public health challenge for malaria treatment and eradication. Individual loci associated with drug resistance to many antimalarials have been identified, but their epistasis with other resistance mechanisms has not yet been elucidated. Results: We previously described two mutations in the cytoplasmic prolyl-tRNA synthetase (cPRS) gene that confer resistance to halofuginone. We describe here the evolutionary trajectory of halofuginone resistance of two independent drug resistance selections in Plasmodium falciparum. Using this novel methodology, we discover an unexpected non-genetic drug resistance mechanism that P. falciparum utilizes before genetic modification of the cPRS. P. falciparum first upregulates its proline amino acid homeostasis in response to halofuginone pressure. We show that this non-genetic adaptation to halofuginone is not likely mediated by differential RNA expression and precedes mutation or amplification of the cPRS gene. By tracking the evolution of the two drug resistance selections with whole genome sequencing, we further demonstrate that the cPRS locus accounts for the majority of genetic adaptation to halofuginone in P. falciparum. We further validate that copy-number variations at the cPRS locus also contribute to halofuginone resistance. Conclusions: We provide a three-step model for multi-locus evolution of halofuginone drug resistance in P. falciparum. Informed by genomic approaches, our results provide the first comprehensive view of the evolutionary trajectory malaria parasites take to achieve drug resistance. Our understanding of the multiple genetic and non-genetic mechanisms of drug resistance informs how we will design and pair future anti-malarials for clinical use. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0511-2) contains supplementary material, which is available to authorized users

Release of Sequestered Malaria Parasites upon Injection of a Glycosaminoglycan

Severe human malaria is attributable to an excessive sequestration of Plasmodium falciparum–infected and uninfected erythrocytes in vital organs. Strains of P. falciparum that form rosettes and employ heparan sulfate as a host receptor are associated with development of severe forms of malaria. Heparin, which is similar to heparan sulfate in that it is composed of the same building blocks, was previously used in the treatment of severe malaria, but it was discontinued due to the occurrence of serious side effects such as intracranial bleedings. Here we report to have depolymerized heparin by periodate treatment to generate novel glycans (dGAG) that lack anticoagulant-activity. The dGAGs disrupt rosettes, inhibit merozoite invasion of erythrocytes and endothelial binding of P. falciparum–infected erythrocytes in vitro, and reduce sequestration in in vivo models of severe malaria. An intravenous injection of dGAGs blocks up to 80% of infected erythrocytes from binding in the micro-vasculature of the rat and releases already sequestered parasites into circulation. P. falciparum–infected human erythrocytes that sequester in the non-human primate Macaca fascicularis were similarly found to be released in to the circulation upon a single injection of 500 μg of dGAG. We suggest dGAGs to be promising candidates for adjunct therapy in severe malaria

Allele Frequency–Based and Polymorphism-Versus-Divergence Indices of Balancing Selection in a New Filtered Set of Polymorphic Genes in Plasmodium falciparum

Signatures of balancing selection operating on specific gene loci in endemic pathogens can identify candidate targets of naturally acquired immunity. In malaria parasites, several leading vaccine candidates convincingly show such signatures when subjected to several tests of neutrality, but the discovery of new targets affected by selection to a similar extent has been slow. A small minority of all genes are under such selection, as indicated by a recent study of 26 Plasmodium falciparum merozoite-stage genes that were not previously prioritized as vaccine candidates, of which only one (locus PF10_0348) showed a strong signature. Therefore, to focus discovery efforts on genes that are polymorphic, we scanned all available shotgun genome sequence data from laboratory lines of P. falciparum and chose six loci with more than five single nucleotide polymorphisms per kilobase (including PF10_0348) for in-depth frequency–based analyses in a Kenyan population (allele sample sizes >50 for each locus) and comparison of Hudson–Kreitman–Aguade (HKA) ratios of population diversity (π) to interspecific divergence (K) from the chimpanzee parasite Plasmodium reichenowi. Three of these (the msp3/6-like genes PF10_0348 and PF10_0355 and the surf4.1 gene PFD1160w) showed exceptionally high positive values of Tajima's D and Fu and Li's F indices and have the highest HKA ratios, indicating that they are under balancing selection and should be prioritized for studies of their protein products as candidate targets of immunity. Combined with earlier results, there is now strong evidence that high HKA ratio (as well as the frequency-independent ratio of Watterson's θ/K) is predictive of high values of Tajima's D. Thus, the former offers value for use in genome-wide screening when numbers of genome sequences within a species are low or in combination with Tajima's D as a 2D test on large population genomic samples

Sequence-Based Association and Selection Scans Identify Drug Resistance Loci in the Plasmodium Falciparum Malaria Parasite

Through rapid genetic adaptation and natural selection, the Plasmodium falciparum parasite—the deadliest of those that cause malaria—is able to develop resistance to antimalarial drugs, thwarting present efforts to control it. Genome-wide association studies (GWAS) provide a critical hypothesis-generating tool for understanding how this occurs. However, in P. falciparum, the limited amount of linkage disequilibrium hinders the power of traditional array-based GWAS. Here, we demonstrate the feasibility and power improvements gained by using whole-genome sequencing for association studies. We analyzed data from 45 Senegalese parasites and identified genetic changes associated with the parasites’ in vitro response to 12 different antimalarials. To further increase statistical power, we adapted a common test for natural selection, XP-EHH (cross-population extended haplotype homozygosity), and used it to identify genomic regions associated with resistance to drugs. Using this sequence-based approach and the combination of association and selection-based tests, we detected several loci associated with drug resistance. These loci included the previously known signals at pfcrt, dhfr, and pfmdr1, as well as many genes not previously implicated in drug-resistance roles, including genes in the ubiquitination pathway. Based on the success of the analysis presented in this study, and on the demonstrated shortcomings of array-based approaches, we argue for a complete transition to sequence-based GWAS for small, low linkage-disequilibrium genomes like that of P. falciparum.Molecular and Cellular BiologyOrganismic and Evolutionary Biolog

Default Pathway of var2csa Switching and Translational Repression in Plasmodium falciparum

Antigenic variation is a subtle process of fundamental importance to the survival of a microbial pathogen. In Plasmodium falciparum malaria, PfEMP1 is the major variable antigen and adhesin expressed at the surface of the infected erythrocyte, which is encoded for by members of a family of 60 var-genes. Peri-nuclear repositioning and epigenetic mechanisms control their mono-allelic expression. The switching of PfEMP1 depends in part on variable transition rates and short-lived immune responses to shared minor epitopes. Here we show var-genes to switch to a common gene that is highly transcribed, but sparsely translated into PfEMP1 and not expressed at the erythrocyte surface. Highly clonal and adhesive P. falciparum, which expressed distinct var-genes and the corresponding PfEMP1s at onset, were propagated without enrichment or panning. The parasites successively and spontaneously switched to transcribe a shared var-gene (var2csa) matched by the loss of PfEMP1 surface expression and host cell-binding. The var2csa gene repositioned in the peri-nuclear area upon activation, away from the telomeric clusters and heterochromatin to transcribe spliced, full-length RNA. Despite abundant transcripts, the level of intracellular PfEMP1 was low suggesting post-transcriptional mechanisms to partake in protein expression. In vivo, off-switching and translational repression may constitute one pathway, among others, coordinating PfEMP1 expression