138 research outputs found

    HelF, a putative RNA helicase acts as a nuclear suppressor of RNAi but not antisense mediated gene silencing

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    We have identified a putative RNA helicase from Dictyostelium that is closely related to drh-1, the ‘dicer-related-helicase’ from Caenorhabditis elegans and that also has significant similarity to proteins from vertebrates and plants. Green fluorescent protein (GFP)-tagged HelF protein was localized in speckles in the nucleus. Disruption of the helF gene resulted in a mutant morphology in late development. When transformed with RNAi constructs, HelF(−) cells displayed enhanced RNA interference on four tested genes. One gene that could not be knocked-down in the wild-type background was efficiently silenced in the mutant. Furthermore, the efficiency of silencing in the wild-type was dramatically improved when helF was disrupted in a secondary transformation. Silencing efficiency depended on transcription levels of hairpin RNA and the threshold was dramatically reduced in HelF(−) cells. However, the amount of siRNA did not depend on hairpin transcription. HelF is thus a natural nuclear suppressor of RNA interference. In contrast, no improvement of gene silencing was observed when mutant cells were challenged with corresponding antisense constructs. This indicates that RNAi and antisense have distinct requirements even though they may share parts of their pathways

    The possibilities for a competition horse to spend time outdoors in a paddock

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    Idag anvÀnds hÀsten frÀmst i sportsammanhang och som fritidssysselsÀttning genom ridning och körning. Det vanligaste sÀttet att hÄlla hÀstar pÄ i Sverige under 2010 Àr stall med boxar med begrÀnsad utevistelse en och en eller i grupp. Det finns fÄ studier gjorda pÄ hÀstens rörelsemÀngd i paddockar. De studier som finns har visat att rörelsemÀngden ökar i större hagar. En studie gjord pÄ Flyinge 2005 indikerar pÄ att hÀstar som gÄr i par har större aktivitet i hagen Àn hÀstar som gÄr enskilt. Syftet med studien Àr att ta reda pÄ om hÀstarna rör sig mer vid utevistelsen om de gÄr i par jÀmfört med om de gÄr enskilt. Studiens frÄgestÀllning Àr: Stimuleras hÀstarna till ökad rörelseaktivitet om de gÄr parvis i hagen jÀmfört med om de gÄr enskilt? Hypotesen Àr att utevistelse i par stimulerar till ökad rörelseaktivitet i form av tillryggalagd strÀcka jÀmfört med hÀstar som hÄlls enskilt. I studiens försök deltog Ätta hÀstar fördelade pÄ tvÄ par och fyra enskilda. Försöket genomfördes under tvÄ perioder pÄ vardera fyra dagar. HÀstarna gick i hagar de Àr vana att gÄ i pÄ deras ordinarie hagtid 07.00-11.30. MÄtten pÄ hagarna var 10x15 meter. De enskilda hÀstarna deltog endast under en försöksperiod vardera, fördelat pÄ tvÄ Ät gÄngen. HÀstarna i par deltog i bÄda försöksperioderna. HÀstarna försÄgs med varsin GPS-mottagare som registrerade deras tillryggalagda strÀcka under hagvistelsen. Studiens resultat Àr att hÀstarna i par hade en lÀngre registrerad strÀcka Àn hÀstarna som gick enskilt i paddockarna. För hÀstarna i par registrerades en genomsnittlig daglig strÀcka pÄ 2003 meter och motsvarande siffra för de som gick enskilt var 1283 meter. Individuella variationer fanns. Den GPS-teknik som anvÀndes visade sig dock inte vara tillförlitlig med felmarginaler pÄ ± 15-20 meter, vilket resulterade i att den tillryggalagda strÀckan överskattades. Det finns ingenting som motsÀger hypotesen Àven om tekniska fel finns

    Transcriptomics of ivermectin response in Caenorhabditis elegans: Integrating abamectin quantitative trait loci and comparison to the Ivermectin-exposed DA1316 strain

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    Parasitic nematodes pose a significant threat to human and animal health, as well as cause economic losses in the agricultural sector. The use of anthelmintic drugs, such as Ivermectin (IVM), to control these parasites has led to widespread drug resistance. Identifying genetic markers of resistance in parasitic nematodes can be challenging, but the free-living nematode Caenorhabditis elegans provides a suitable model. In this study, we aimed to analyze the transcriptomes of adult C. elegans worms of the N2 strain exposed to the anthelmintic drug Ivermectin (IVM), and compare them to those of the resistant strain DA1316 and the recently identified Abamectin Quantitative Trait Loci (QTL) on chromosome V. We exposed pools of 300 adult N2 worms to IVM (10(-7) and 10(-8) M) for 4 hours at 20 degrees C, extracted total RNA and sequenced it on the Illumina NovaSeq6000 platform. Differentially expressed genes (DEGs) were determined using an in-house pipeline. The DEGs were compared to genes from a previous microarray study on IVM-resistant C. elegans and Abamectin-QTL. Our results revealed 615 DEGs (183 up-regulated and 432 down-regulated genes) from diverse gene families in the N2 C. elegans strain. Of these DEGs, 31 overlapped with genes from IVM-exposed adult worms of the DA1316 strain. We identified 19 genes, including the folate transporter (folt-2) and the transmembrane transporter (T22F3.11), which exhibited an opposite expression in N2 and the DA1316 strain and were deemed potential candidates. Additionally, we compiled a list of potential candidates for further research including T-type calcium channel (cca-1), potassium chloride cotransporter (kcc-2), as well as other genes such as glutamate-gated channel (glc-1) that mapped to the Abamectin-QTL

    FuktsÀker energieffektivisering av befintlig bebyggelse- Kan TES EnergyFacade uppfylla svenska krav?

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    Vi ska undersöka möjligheten att anvĂ€nda ett fasadsystem för att energieffektivisera miljonprogramhus.TES Energy Facade Ă€r ett prisvinnande fasadsystem som anvĂ€nts i övriga Europa. Fasaden har Ă€ven anvĂ€nds inom E2Rebuild-projektet som Ă€r ett samarbetsprojekt mellan 8 EU-lĂ€nder. Ett problem som identifieras inom E2Rebuild Ă€r att fasadsystemet kanske inte uppfyller de svenska kraven för fukt och energi. Syftet med exjobbet Ă€r att undersöka om fasadsystemet TES Energy Facade uppfyller BBR-kraven inom fukt och energi genom fukt – och energiberĂ€kningar. Om fasadsystemet inte uppfyller de svenska kraven ska vi undersöka om det gĂ„r att modifiera fasaden sĂ„ att kraven uppfylls. VĂ„rt referensobjekt kommer vara kvarteret Giganten i Halmstad, som Ă€r ett flerbostadshus byggt under miljonprogrammet pĂ„ 60-talet

    En enkÀtstudie om treÄrstestets regelförÀndringar Är 2013

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    År 1999 införde ASVH (Avelsföreningen för den svenska varmblodiga hĂ€sten) treĂ„rs-testet i syfte att tidigt kunna göra en avkommebedömning och dĂ€rmed fĂ„ ett snabbare avelsframsteg. Fram till Ă„r 2013 har totalt cirka 15 400 hĂ€star visats. TreĂ„riga hĂ€star som visas pĂ„ treĂ„rstest poĂ€ngsĂ€tts pĂ„ Ă„tta bedömningspunkter: typ; huvud, hals & bĂ„l; extremiteter; skritt; trav; galopp; löshoppning teknik & förmĂ„ga samt lös-hoppning temperament & allmĂ€nt intryck. År 2013 infördes en del förĂ€ndringar för att ytterligare utveckla treĂ„rstestet. Som komplement till den vĂ€rderande poĂ€ngbedömningen infördes linjĂ€r beskrivning, löshoppningen Ă€ndrade system frĂ„n tvĂ„ hinder till tre hinder, ridprovet poĂ€ngbedömdes pĂ„ försök och domarna gavs möjlighet till att ge halvpoĂ€ng. För att uppnĂ„ ett avelsframsteg krĂ€vs det att rĂ€tt individer sĂ€tts i avel tidigt, det betyder att en stor del av populationen mĂ„ste testas efter de egenskaper som efterstrĂ€vas i avelsmĂ„let. Sedan toppĂ„ren 2007-2008 med 49 % visade hĂ€star av den totala Ă„rgĂ„ngen har deltagar-antalet pĂ„ SWB treĂ„rstest minskat till att Ă„r 2013 endast innefatta 38 % av den totala Ă„rgĂ„ngen. Syftet med denna studie var att undersöka vad de som visade hĂ€st pĂ„ treĂ„rstest Ă„r 2013 anser om de nya reglerna. Ett negativt gensvar skulle kunna leda till ett lĂ€gre deltagarantal och dĂ€rmed en osĂ€krare avkommebedömning samt ett lĂ„ngsammare avels-framsteg. Studiens frĂ„gestĂ€llningar var: Ser respondenterna positivt eller negativt pĂ„ de nya reglerna? Har de nya reglerna gett ett ökat intresse för att visa hĂ€st pĂ„ treĂ„rstest? PĂ„verkar hĂ€stens avelsinriktning respondenternas syn pĂ„ de nya reglerna? En enkĂ€t skickades via mail till 858 personer som anmĂ€lt minst en hĂ€st till treĂ„rstest Ă„r 2013. Svarsfrekvensen var 39 % vilket motsvarade 338 personer. Resultatet visade att 84 % av respondenterna generellt Ă€r positivt eller mycket positivt instĂ€llda till de nya reglerna införda Ă„r 2013. Av de som besvarade enkĂ€ten kom 97 % till start med sin treĂ„ring, för 31 % av respondenterna var det första gĂ„ngen de visade pĂ„ treĂ„rstest. Motiv till att visa hĂ€st pĂ„ treĂ„rstest ansĂ„gs framförallt vara ett utbildningsmĂ„l för den treĂ„riga hĂ€sten. De nya reglerna har dock inte bidragit till ett ökat intresse för att visa hĂ€st pĂ„ treĂ„rstestet hos respondenterna dĂ„ 62 % ansĂ„g att intresset var oförĂ€ndrat. Slutsatsen Ă€r att majoriteten av respondenterna Ă€r positiva till de nya regelförĂ€ndringarna som infördes pĂ„ treĂ„rstest för svenska varmblodiga hĂ€sten Ă„r 2013. De nya reglerna har dock inte pĂ„verkat respondenterna till att bli mer positivt instĂ€llda till att visa hĂ€st pĂ„ treĂ„rstest. En viss skillnad (p<0,05) i respondenternas Ă„sikt angĂ„ende ridprovet kunde ses beroende pĂ„ avelsinriktning. Respondenter med hĂ€st avlad mot dressyr var mer positivt instĂ€llda till införandet av poĂ€ngbedömning av ridprov Ă€n respondenter med hĂ€st avlad mot hoppning. De respondenter som angav att deras hĂ€st/ar var avlade mot dressyr ansĂ„g ocksĂ„ i större utstrĂ€ckning att poĂ€ngbedömningen var av vĂ€rde för dem

    Experimentally reduced insulin/IGF-1 signaling in adulthood extends lifespan of parents and improves Darwinian fitness of their offspring

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    Classical theory maintains that ageing evolves via energy trade-offs between reproduction and survival leading to accumulation of unrepaired cellular damage with age. In contrast, the emerging new theory postulates that ageing evolves because of deleterious late-life hyper-function of reproduction-promoting genes leading to excessive biosynthesis in late-life. The hyper-function theory uniquely predicts that optimizing nutrient-sensing molecular signaling in adulthood can simultaneously postpone ageing and increase Darwinian fitness. Here, we show that reducing evolutionarily conserved insulin/IGF-1 nutrient-sensing signaling via daf-2 RNA interference (RNAi) fulfils this prediction in Caenorhabditis elegans nematodes. Long-lived daf-2 RNAi parents showed normal fecundity as self-fertilizing hermaphrodites and improved late-life reproduction when mated to males. Remarkably, the offspring of daf-2 RNAi parents had higher Darwinian fitness across three different genotypes. Thus, reduced nutrient-sensing signaling in adulthood improves both parental longevity and offspring fitness supporting the emerging view that suboptimal gene expression in late-life lies at the heart of ageing

    Sickness-certification practice in different clinical settings; a survey of all physicians in a country

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    <p>Abstract</p> <p>Background</p> <p>How physicians handle sickness-certification is essential in the sickness-absence process. Few studies have focused this task of physicians' daily work. Most previous studies have only included general practitioners. However, a previous study indicated that this is a common task also among other physicians. The aim of this study was to gain detailed knowledge about physicians' work with sickness-certification and of the problems they experience in this work.</p> <p>Methods</p> <p>A comprehensive questionnaire regarding sickness-certification practice was sent home to all physicians living and working in Sweden (N = 36,898; response rate: 61%). This study included physicians aged <65 years who had sickness-certification consultations at least a few times a year (n = 14,210). Descriptive statistics were calculated and odds ratios (OR) with 95 % confidence intervals (CI) were estimated for having different types of related problems, stratified on clinical settings, using physicians working in internal medicine as reference group.</p> <p>Results</p> <p>Sickness-certification consultations were frequent; 67% of all physicians had such, and of those, 83% had that at least once a week. The proportion who had such consultations >5 times a week varied between clinical settings; from 3% in dermatology to 79% in orthopaedics; and was 43% in primary health care. The OR for finding sickness-certification tasks problematic was highest among the physicians working in primary health care (OR 3.3; CI 2.9-3.7) and rheumatology clinics (OR 2.6; CI 1.9-3.5). About 60% found it problematic to assess patients' work capacity and to provide a prognosis regarding the duration of work incapacity.</p> <p>Conclusions</p> <p>So far, most interventions regarding physicians' sickness-certification practices have been targeted towards primary health care and general practitioners. Our results indicate that the ORs for finding these tasks problematic were highest in primary health care. Nevertheless, physicians in some other clinical settings more often have such consultations and many of them also find these tasks problematic, e.g. in rheumatology, neurology, psychiatry, and orthopaedic clinics. Thus, the results indicate that much can be gained through focusing on physicians in other types of clinics as well, when planning interventions to improve sickness-certification practice.</p

    Obstetricians/Gynecologists’ Problems in Sickness Certification Consultations: Two Nationwide Surveys

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    Objective. To explore experiences by physicians working in obstetrics, gynecology, or maternal healthcare (O/Gs) of problems in sickness certification consultations and differences between two years. Material and Methods. Answers by O/Gs to two Swedish nationwide surveys, in 2008 (n=1037) and 2012 (n=992), were analyzed for frequencies and severity of problems and organizational support in sickness certification consultations. Results. One-third of O/Gs found sickness certifications problematic every week. The most frequent problem was patients requesting sick notes for reasons other than work incapacity due to disease/injury (2008: 21%; 2012: 16%). The most problematic were assessing work capacity (2008 and 2012: 52%) and having different opinion from that of the patient about need for sick leave (2008: 51%; 2012: 46%). In 2012, 27% used the national sickness certification guidelines weekly, compared to 9% in 2008. A larger proportion in 2012 than 2008 reported that the guidelines facilitated contacts with patients and different stakeholders. Conclusions. Although O/Gs perceived sickness certification as problematic, there was less perceived severity of problems in 2012 compared to 2008, possibly because interventions regarding sickness certification have been introduced in Sweden recent years. Still, more organizational support, for example, time and supervision, are needed to enhance O/Gs’ sickness certification practices

    Antagonistically pleiotropic allele increases lifespan and late-life reproduction at the cost of early-life reproduction and individual fitness

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    Evolutionary theory of ageing maintains that increased allocation to early-life reproduction results in reduced somatic maintenance, which is predicted to compromise longevity and late-life reproduction. This prediction has been challenged by the discovery of long-lived mutants with no loss of fecundity. The first such long-lived mutant was found in the nematode worm Caenorhabditis elegans. Specifically, partial-loss-of-function mutation in the age-1 gene, involved in the nutrient-sensing insulin/insulin-like growth factor (IIS) signalling pathway, confers longevity, as well as increased resistance to pathogens and to temperature stress without appreciable fitness detriment. Here we show that the long-lived age-1(hx546) mutant has reduced fecundity and offspring production in early-life but increased fecundity, hatching success and offspring production in late-life compared to wild-type worms under standard conditions. However, reduced early-life performance of long-lived mutant animals was not fully compensated by improved performance in late-life and resulted in reduced individual fitness. These results suggest that the age-1(hx546) allele has opposing effects on early-life versus late-life fitness in accordance with antagonistic pleiotropy and disposable soma theories of ageing. These findings support the theoretical conjecture that experimental studies based on standing genetic variation underestimate the importance of antagonistic pleiotropy in the evolution of ageing
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