Crossovers Dotaz Zobrazit nápovědu
The detection of meiotic crossovers in crop plants currently relies on scoring DNA markers in a segregating population or cytological visualization. We investigated the feasibility of using flow-sorted haploid nuclei, Phi29 DNA polymerase-based whole-genome-amplification (WGA) and multi-locus KASP-genotyping to measure meiotic crossovers in individual barley pollen grains. To demonstrate the proof of concept, we used 24 gene-based physically mapped single nucleotide polymorphisms to genotype the WGA products of 50 single pollen nuclei. The number of crossovers per chromosome, recombination frequencies along chromosome 3H and segregation distortion were analysed and compared to a doubled haploid (DH) population of the same genotype. The number of crossovers and chromosome wide recombination frequencies show that this approach is able to produce results that resemble those obtained from other methods in a biologically meaningful way. Only the segregation distortion was found to be lower in the pollen population than in DH plants.
- MeSH
- chromozomy rostlin MeSH
- crossing over (genetika) * MeSH
- DNA rostlinná MeSH
- genom rostlinný MeSH
- haploidie MeSH
- ječmen (rod) genetika MeSH
- lokus kvantitativního znaku MeSH
- meióza genetika MeSH
- multilokusová sekvenční typizace * MeSH
- pyl genetika MeSH
- rekombinace genetická MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- DNA rostlinná MeSH
- MeSH
- aminy farmakologie MeSH
- crossing over (genetika) účinky léků účinky záření MeSH
- Drosophila účinky léků účinky záření MeSH
- ethyl-karbamát farmakologie MeSH
- meióza účinky léků účinky záření MeSH
- nitrososloučeniny farmakologie MeSH
- piperaziny farmakologie MeSH
- radiační účinky * MeSH
- rozmnožování účinky léků účinky záření MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aminy MeSH
- ethyl-karbamát MeSH
- nitrososloučeniny MeSH
- piperaziny MeSH
Homologous chromosomes exchange genetic information through recombination during meiosis, a process that increases genetic diversity, and is fundamental to sexual reproduction. In an attempt to shed light on the dynamics of mammalian recombination and its implications for genome organization, we have studied the recombination characteristics of 112 individuals belonging to 28 different species in the family Bovidae. In particular, we analyzed the distribution of RAD51 and MLH1 foci during the meiotic prophase I that serve, respectively, as proxies for double-strand breaks (DSBs) which form in early stages of meiosis and for crossovers. In addition, synaptonemal complex length and meiotic DNA loop size were estimated to explore how genome organization determines DSBs and crossover patterns. We show that although the number of meiotic DSBs per cell and recombination rates observed vary between individuals of the same species, these are correlated with diploid number as well as with synaptonemal complex and DNA loop sizes. Our results illustrate that genome packaging, DSB frequencies, and crossover rates tend to be correlated, while meiotic chromosomal axis length and DNA loop size are inversely correlated in mammals. Moreover, axis length, DSB frequency, and crossover frequencies all covary, suggesting that these correlations are established in the early stages of meiosis.
- Klíčová slova
- Bovidae, Crossovers, MLH1, Meiosis, RAD51, Recombination,
- MeSH
- dvouřetězcové zlomy DNA MeSH
- meióza * MeSH
- MutL homolog 1 MeSH
- myši MeSH
- přežvýkavci genetika metabolismus MeSH
- rekombinace genetická * MeSH
- rekombinasa Rad51 MeSH
- savčí chromozomy metabolismus ultrastruktura MeSH
- synaptonemální komplex metabolismus ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- MutL homolog 1 MeSH
- rekombinasa Rad51 MeSH
BACKGROUND: The ongoing increase in the mean global temperature due to human induced climate change, indicates that women and infants will have higher exposure to heat events leading to adverse outcomes. The study investigates the effect of non-optimal ambient temperature on the risk of preterm birth stratified by social position in Nepal. METHOD: This is a space-time-stratified case-crossover design, based on hospital-registered perinatal data between 2017 and 2021 (n = 47,807). A daily count of pregnant women residing in seven heat-prone districts was extracted together with their social status (ethnicity), obstetric complication and gestation of birth. The daily count of events was matched with the daily ambient temperature of their residence using the NOAA spatial temperature recording. Ambient temperature exposure was analysed using conditional Poisson regression and distributed lag non-linear models. FINDINGS: In the general population, with exposure to ambient temperature at the 75th centile (28 °C) the cumulative risk of preterm birth over 28 days was 1·29 times higher (RR, 1·29; 95% CI; 1·09, 1·54) than at median temperature (24.1 °C), and even higher among the socially disadvantaged population. Cumulative risk of preterm birth to cold ambient temperature at the 1st centile was high but not significant. Exposure to ambient temperature at the 90th centile (32·5 °C) had the highest cumulative risk of preterm birth for pregnant women from socially disadvantaged populations (RR 1·81; 95% CI; 1·28, 2·55). The delayed effect after exposure to temperatures above the 75th percentile was more prolonged in the disadvantaged than the advantaged social group. CONCLUSION: Although exposure to cold with certain effect on preterm births, heat (increase in ambient temperature) carries a risk of preterm birth in Nepal, and is more profound among socially disadvantaged populations.
- Klíčová slova
- Nepal, Non-optimal ambient temperature, Preterm birth, Social inequality,
- MeSH
- dospělí MeSH
- klimatické změny MeSH
- klinické křížové studie * MeSH
- lidé MeSH
- mladý dospělý MeSH
- novorozenec MeSH
- předčasný porod * epidemiologie MeSH
- těhotenství MeSH
- teplota MeSH
- vysoká teplota škodlivé účinky MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- novorozenec MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Nepál epidemiologie MeSH
INTRODUCTION: Meiotic recombination is one of the most important processes of evolution and adaptation to environmental conditions. Even though there is substantial knowledge about proteins involved in the process, targeting specific DNA loci by the recombination machinery is not well understood. OBJECTIVES: This study aims to investigate a wheat recombination hotspot (H1) in comparison with a "regular" recombination site (Rec7) on the sequence and epigenetic level in conditions with functional and non-functional Ph1 locus. METHODS: The DNA sequence, methylation pattern, and recombination frequency were analyzed for the H1 and Rec7 in three mapping populations derived by crossing introgressive wheat line 8.1 with cv. Chinese Spring (with Ph1 and ph1 alleles) and cv. Tähti. RESULTS: The H1 and Rec7 loci are 1.586 kb and 2.538 kb long, respectively. High-density mapping allowed to delimit the Rec7 and H1 to 19 and 574 bp and 593 and 571 bp CO sites, respectively. A new method (ddPing) allowed screening recombination frequency in almost 66 thousand gametes. The screening revealed a 5.94-fold higher recombination frequency at the H1 compared to the Rec7. The H1 was also found out of the Ph1 control, similarly as gamete distortion. The recombination was strongly affected by larger genomic rearrangements but not by the SNP proximity. Moreover, chromatin markers for open chromatin and DNA hypomethylation were found associated with crossover occurrence except for the CHH methylation. CONCLUSION: Our results, for the first time, allowed study of wheat recombination directly on sequence, shed new light on chromatin landmarks associated with particular recombination sites, and deepened knowledge about role of the Ph1 locus in control of wheat recombination processes. The results are suggesting more than one recombination control pathway. Understanding this phenomenon may become a base for more efficient wheat genome manipulation, gene pool enrichment, breeding, and study processes of recombination itself.
- Klíčová slova
- Crossovers, DNA methylation, Hotspot, Ph1 locus, Recombination, Wheat,
- MeSH
- chromatin * genetika MeSH
- chromozomy MeSH
- DNA MeSH
- pšenice * genetika MeSH
- šlechtění rostlin MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- chromatin * MeSH
- DNA MeSH
Long-chain n-3 polyunsaturated fatty acids modulate immune cell functions. The primary objective of this study was to evaluate the impact of different lipid emulsions (LEs) with supplemented doses of fish oil (FO) on serum cytokine concentration and in vitro cytokine production in patients with intestinal failure on home parenteral nutrition (HPNPs). We hypothesized that FO supplementation would diminish lipopolysaccharide (LPS)-stimulated cytokine production. Twelve HPNPs receiving Smoflipid for at least 3 months were given FO (Omegaven) for a further 4 weeks. After this cycle, the patients were randomized to subsequently receive 1 cycle with Lipoplus and 1 cycle with ClinOleic for 6 weeks or vice versa plus 4 weeks of added Omegaven after each cycle in a crossover design. Comparison of the baseline LE regimens showed lower LPS-stimulated production of IL-1β in the HPNPs on Lipoplus than on the Smoflipid and ClinOleic regimens, as well as lower IL-8 compared to the Smoflipid regimen. Omegaven reduced IL-8 concentration in serum under the Lipoplus regimen and diminished LPS-stimulated production of IL-1β under the Smoflipid and ClinOleic. IL-6 and TNF-α production was depressed only in those on Smoflipid. Irrespective of the LE used, the HPNPs compared to the healthy controls showed higher IL-6, IL-8, and TNF-α concentrations in serum and LPS-stimulated production of IL-6 as well as lower n-6/n-3 long-chain polyunsaturated fatty acids in the erythrocyte phospholipids. LPS-stimulated production of IL-6 correlated negatively with the parenteral dose of eicosapentaenoic acid + docosahexaenoic acid. In conclusion, FO-supplemented parenteral nutrition suppresses in vitro cytokine production.
- Klíčová slova
- Crossover study, Fish oil, Home parenteral nutrition, Inflammation, Lipopolysaccharide stimulation,
- MeSH
- cytokiny krev MeSH
- dospělí MeSH
- klinické křížové studie MeSH
- lidé středního věku MeSH
- lidé MeSH
- parenterální výživa doma metody MeSH
- potravní doplňky MeSH
- rybí oleje aplikace a dávkování krev farmakologie MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- techniky in vitro MeSH
- tukové emulze intravenózní aplikace a dávkování metabolismus farmakologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- randomizované kontrolované studie MeSH
- Názvy látek
- cytokiny MeSH
- rybí oleje MeSH
- tukové emulze intravenózní MeSH
BACKGROUND: Changes in oxygen saturation (SpO2) exposure have been shown to have a marked impact on neonatal outcomes and therefore careful titration of inspired oxygen is essential. In routine use, however, the frequency of SpO2 alarms not requiring intervention results in alarm fatigue and its corresponding risk. SpO2 control systems that automate oxygen adjustments (Auto-FiO2) have been shown to be safe and effective. We speculated that when using Auto-FiO2, alarm settings could be refined to reduce unnecessary alarms, without compromising safety. METHODS: An unblinded randomized crossover study was conducted in a single NICU among infants routinely managed with Auto-FiO2. During the first 6 days of respiratory support a tight and a loose alarm strategy were switched each 24 h. A balanced block randomization was used. The tight strategy set the alarms at the prescribed SpO2 target range, with a 30-s delay. The loose strategy set the alarms 2 wider, with a 90-s delay. The effectiveness outcome was the frequency of SpO2 alarms, and the safety outcomes were time at SpO2 extremes (< 80, > 98%). We hypothesized that the loose strategy would result in a marked decrease in the frequency of SpO2 alarms, and no increases at SpO2 extremes with 20 subjects. Within subject differences between alarm strategies for the primary outcomes were evaluated with Wilcoxon signed-rank test. RESULTS: During a 13-month period 26 neonates were randomized. The analysis included 21 subjects with 49 days of both tight and loose intervention. The loose alarm strategy resulted in a reduction in the median rate of SpO2 alarms from 5.2 to 1.6 per hour (p < 0.001, 95%-CI difference 1.6-3.7). The incidence of hypoxemia and hyperoxemia were very low (less than 0.1%-time) with no difference associated with the alarm strategy (95%-CI difference less than 0.0-0.2%). CONCLUSIONS: In this group of infants we found a marked advantage of the looser alarm strategy. We conclude that the paradigms of alarm strategies used for manual titration of oxygen need to be reconsidered when using Auto-FiO2. We speculate that with optimal settings false positive SpO2 alarms can be minimized, with better vigilance of clinically relevant alarms. TRIAL REGISTRATION: Retrospectively registered 15 May 2018 at ISRCTN ( 49239883 ).
- Klíčová slova
- Alarm fatigue, Automated oxygen control, Oxygen saturation,
- MeSH
- automatizace MeSH
- hypoxie prevence a kontrola MeSH
- jednotky intenzivní péče o novorozence MeSH
- klinické alarmy * MeSH
- klinické křížové studie MeSH
- lidé MeSH
- monitorování fyziologických funkcí MeSH
- nemocnice veřejné MeSH
- novorozenec nedonošený * MeSH
- novorozenec MeSH
- oxygenoterapie metody MeSH
- oxymetrie MeSH
- péče o pacienty v kritickém stavu metody MeSH
- prognóza MeSH
- spotřeba kyslíku fyziologie MeSH
- umělé dýchání metody MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
- Geografické názvy
- Polsko MeSH
OBJECTIVES: This study quantified blood bicarbonate (HCO3-) kinetics and gastrointestinal upset to determine the gender-related ergogenic potential of sodium bicarbonate (0.15-, 0.25- and 0.35 gSB·kgFat-free mass (FFM)-1) in high intensity functional training. DESIGN: Double-blind randomized placebo-controlled crossover. METHODS: Thirty female and male athletes performed two bouts of the Wingate Anaerobic Test (WAnTPRE-HIFT and WAnTPOST-HIFT) interspaced with two 3-min bouts of Wall Balls and Burpees 120 min after ingestion of three sodium bicarbonate doses. Blood HCO3- was determined pre-ingestion, after supplementation and before/post exercise. Gastrointestinal upset was evaluated 120 min post-ingestion. Control (CTRL) measurements were performed. RESULTS: There were significant gender × treatment interactions for: changes in blood HCO3- at 60 min post-ingestion (p = 0.014; η2p = 0.104; at 0.15 gSB·kgFFM-1 males experienced higher increase than females); peak power (p = 0.015; η2p = 0.103) and average power (p = 0.005; η2p = 0.124) during WAnTPOST-HIFT, and changes in peak power between the Wingate Anaerobic Test bouts (p = 0.049; η2p = 0.081). Sodium bicarbonate compared to PLA had no significant impact on Wall Balls and Burpees performance. The dose of 0.35 gSB·kgFFM-1 resulted in higher less severe gastrointestinal symptoms compared to CTRL and 0.15 gSB·kgFFM-1 (p = 0.001; W = 0.178); and higher total gastrointestinal upset compared to CTRL, PLA and 0.15 gSB·kgFFM-1 (p < 0.001; W = 0.323). CONCLUSIONS: There were dose- and gender-related differences in extracellular buffering capacity and ergogenic potential of sodium bicarbonate. The study suggested a detrimental impact of gastrointestinal upset on performance.
- Klíčová slova
- Anaerobic capacity, Buffering agents, Exercise performance, High-intensity interval training, Side effects, Supplementation,
- MeSH
- dospělí MeSH
- dvojitá slepá metoda MeSH
- hydrogenuhličitan sodný * aplikace a dávkování farmakologie krev MeSH
- klinické křížové studie * MeSH
- látky zvyšující výkon aplikace a dávkování farmakologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- sexuální faktory MeSH
- zátěžový test MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
- Názvy látek
- hydrogenuhličitan sodný * MeSH
- látky zvyšující výkon MeSH
OBJECTIVE: The objective of this study was to compare two different modes of ventilation in maintaining oxygen saturation (SpO2) in target range (90%-95%) in ventilated preterm infants cared for with automatic control of oxygen delivery (A-FiO2). DESIGN: A single-centre randomised crossover study. SETTINGS: A level III neonatal intensive care unit. PATIENTS: Preterm infants receiving mechanical ventilation and oxygen requirement >21%. INTERVENTIONS: Volume guarantee (VG) vs volume controlled ventilation (VCV) modes with automatic oxygen control (A-FiO2). OUTCOMES: The primary outcome of this study was the proportion of time spent with oxygen saturations in the target range (90%-95%) . RESULTS: Nineteen preterm infants with a median gestation age 25 weeks (IQR: 24-28) and birth weight 685 g (IQR: 595-980) were enrolled in the study. There was no significant difference in primary outcome of median proportion of time spent in target saturation between the two arms (72% (57-81) in VG vs 75% (58-83) in VCV; p=0.98). There was no significant difference in the secondary outcomes of time spent in SpO2 <80% (0.03% vs 0.14%; p=0.51), time spent in SpO2 >98% (0.50% vs 0.08%; p=0.54), the median FiO2 (31% vs 29%; p=0.51) or manual adjustments carried out between VG and VCV, respectively. The number of episodes of prolonged hypoxaemia and hyperoxaemia were similar in the two groups. CONCLUSION: There was no significant difference in time spent in target SpO2 range between VG and VCV when A-FiO2 was used as the FiO2 controller in this crossover randomised control study. TRIAL REGISTRATION NUMBER: NCT03865069.
- Klíčová slova
- neonatology, technology,
- MeSH
- jednotky intenzivní péče o novorozence MeSH
- klinické křížové studie MeSH
- kyslík terapeutické užití MeSH
- lidé MeSH
- neinvazivní ventilace MeSH
- novorozenec nedonošený * MeSH
- novorozenec MeSH
- oxygenoterapie metody MeSH
- oxymetrie metody MeSH
- syndrom respirační tísně novorozenců prevence a kontrola MeSH
- umělé dýchání metody MeSH
- ventilace umělá s přerušovaným přetlakem * MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
- klinické zkoušky MeSH
- randomizované kontrolované studie MeSH
- Názvy látek
- kyslík MeSH
BACKGROUND: Aim of the study was to compare metabolic response of leg skeletal muscle during functional electrical stimulation-driven unloaded cycling (FES) to that seen during volitional supine cycling. METHODS: Fourteen healthy volunteers were exposed in random order to supine cycling, either volitional (10-25-50 W, 10 min) or FES assisted (unloaded, 10 min) in a crossover design. Whole body and leg muscle metabolism were assessed by indirect calorimetry with concomitant repeated measurements of femoral venous-arterial differences of blood gases, glucose, lactate and amino acids. RESULTS: Unloaded FES cycling, but not volitional exercise, led to a significant increase in across-leg lactate production (from -1.1±2.1 to 5.5±7.4 mmol/min, p<0.001) and mild elevation of arterial lactate (from 1.8±0.7 to 2.5±0.8 mM). This occurred without widening of across-leg veno-arterial (VA) O2 and CO2 gaps. Femoral SvO2 difference was directly proportional to VA difference of lactate (R2 = 0.60, p = 0.002). Across-leg glucose uptake did not change with either type of exercise. Systemic oxygen consumption increased with FES cycling to similarly to 25W volitional exercise (138±29% resp. 124±23% of baseline). There was a net uptake of branched-chain amino acids and net release of Alanine from skeletal muscle, which were unaltered by either type of exercise. CONCLUSIONS: Unloaded FES cycling, but not volitional exercise causes significant lactate production without hypoxia in skeletal muscle. This phenomenon can be significant in vulnerable patients' groups.
- MeSH
- aminokyseliny metabolismus MeSH
- arteria femoralis metabolismus MeSH
- bérec MeSH
- cyklistika fyziologie MeSH
- dospělí MeSH
- elektrická stimulace MeSH
- klinické křížové studie MeSH
- kosterní svaly metabolismus MeSH
- kyselina mléčná biosyntéza krev MeSH
- kyslík krev MeSH
- lidé MeSH
- mladý dospělý MeSH
- nepřímá kalorimetrie MeSH
- oxid uhličitý krev MeSH
- spotřeba kyslíku MeSH
- supinační poloha fyziologie MeSH
- terapie cvičením metody MeSH
- vena femoralis metabolismus MeSH
- zdraví dobrovolníci pro lékařské studie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aminokyseliny MeSH
- kyselina mléčná MeSH
- kyslík MeSH
- oxid uhličitý MeSH