sequence randomization
Dotaz
Zobrazit nápovědu
All grass species evolved from an ancestor that underwent a whole-genome duplication (WGD) approximately 70 million years ago. Interestingly, the short arms of rice chromosomes 11 and 12 (and independently their homologs in sorghum) were found to be much more similar to each other than other homeologous regions within the duplicated genome. Based on detailed analysis of rice chromosomes 11 and 12 and their homologs in seven grass species, we propose a mechanism that explains the apparently 'younger' age of the duplication in this region of the genome, assuming a small number of reciprocal translocations at the chromosome termini. In each case the translocations were followed by unbalanced transmission and subsequent lineage sorting of the involved chromosomes to offspring. Molecular dating of these translocation events also allowed us to date major chromosome 'fusions' in the evolutionary lineages that led to Brachypodium and Triticeae. Furthermore, we provide evidence that rice is exceptional regarding the evolution of chromosomes 11 and 12, inasmuch as in other species the process of sequence exchange between homeologous chromosomes ceased much earlier than in rice. We presume that random events rather than selective forces are responsible for the observed high similarity between the short arm ends of rice chromosomes 11 and 12.
- MeSH
- časové faktory MeSH
- chromozomy rostlin genetika MeSH
- druhová specificita MeSH
- duplikace genu MeSH
- fylogeneze MeSH
- genetická variace MeSH
- genom rostlinný genetika MeSH
- lipnicovité klasifikace genetika MeSH
- molekulární evoluce * MeSH
- molekulární sekvence - údaje MeSH
- rekombinace genetická MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- sekvenční homologie nukleových kyselin MeSH
- selekce (genetika) MeSH
- syntenie MeSH
- translokace genetická MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
BACKGROUND: Rapid sequence induction (RSI) is a standard procedure, which should be implemented in all patients with a risk of aspiration/regurgitation during anaesthesia induction. OBJECTIVE: The primary aim was to evaluate clinical practice in RSI, both in adult and paediatric populations. DESIGN: Online survey. SETTINGS: A total of 56 countries. PARTICIPANTS: Members of the European Society of Anaesthesiology. MAIN OUTCOME MEASURES: The aim was to identify and describe the actual clinical practice of RSI related to general anaesthesia. RESULTS: From the 1921 respondents, 76.5% (n=1469) were qualified anaesthesiologists. When anaesthetising adults, the majority (61.7%, n=1081) of the respondents preoxygenated patients with 100% O2 for 3 min and 65.9% (n=1155) administered opioids during RSI. The Sellick manoeuvre was used by 38.5% (n=675) and was not used by 37.4% (n=656) of respondents. First-line medications for a haemodynamically stable adult patient were propofol (90.6%, n=1571) and suxamethonium (56.0%, n=932). Manual ventilation (inspiratory pressure <12 cmH2O) was used in 35.5% (n=622) of respondents. In the majority of paediatric patients, 3 min of preoxygenation (56.6%, n=817) and opioids (54.9%, n=797) were administered. The Sellick manoeuvre and manual ventilation (inspiratory pressure <12 cmH2O) in children were used by 23.5% (n=340) and 35.9% (n=517) of respondents, respectively. First-line induction drugs for a haemodynamically stable child were propofol (82.8%, n=1153) and rocuronium (54.7%, n=741). CONCLUSION: We found significant heterogeneity in the daily clinical practice of RSI. For patient safety, our findings emphasise the need for international RSI guidelines. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03694860.
Cíl: Rapid sequence induction (RSI) jako soubor klinických postupů a opatření s cílem minimalizovat riziko aspirace a desaturace během úvodu do anestezie je součástí každodenní anesteziologické praxe. Vzhledem k aktuálně chybějícímu národnímu (českému) a mezinárodnímu doporučení je praxe RSI variabilní. Cílem dotazníkového šetření bylo zhodnotit variabilitu RSI u čtyř modelových situací (dospělý pacient s náhlou příhodou břišní /NPB/, dětský pacient s NPB, těhotná pacientka indikovaná k elektivnímu císařskému řezu v celkové anestezii a geriatrický obézní pacient s hiátovou hernií). Typ studie: Dotazníkové šetření (survey). Materiál a metoda: Dotazník byl rozeslán členům České společnosti anesteziologie, resuscitace a intenzivní medicíny a současně účastníkům lékařské sekce VIII. konference akutně.cz 2016. Výsledky byly hodnoceny metodami deskriptivní statistiky (MS Excel). Výsledky: Do akce se zapojilo celkem 164 lékařů (procento získaných odpovědí – 12,5 %). V indikacích RSI a taky v jednotlivých krocích postupu byla identifikována vysoká variabilita jak u lékařů v předatestační přípravě, tak u lékařů s ukončenou specializací. Závěr: Výsledky poukazují na variabilitu v provedení RSI u jednotlivých klinických scénářů (dospělý, dítě, těhotná). Zavedení doporučení založených na evidence-based medicine (EBM) a standardizace RSI postupu může vést ke zvýšení bezpečnosti pacientů během anesteziologické péče.
Objective: Rapid sequence induction (RSI) is a set of clinical techniques and precautions aimed at minimizing the risk of aspiration of gastric contents in at-risk patients. RSI is a part of everyday anaesthetic clinical practice. Due to the lack of national and international guidelines the actual RSI varies in clinical practice. The aim of the survey was to evaluate the variability of RSI based on four model clinical scenarios (adult patient with acute abdomen, paediatric patient with acute abdomen, parturient scheduled for elective caesarean section and geriatric obese patient with hiatus hernia). Design: Survey (electronic form). Materials and methods: The survey was sent to the Czech Society of Anaesthesiology and Intensive Care Medicine members and to the 2016 AKUTNE.CZ conference attendees. Results: Total 164 completed questionnaires were returned (response rate 12.5%). The results indicated high variability in the indications and technique of RSI in clinical practice, both in trainees and qualified anaesthetists. Conclusion: The results highlighted urgent need for a national RSI guidelines formulation for specific clinical scenarios (adult, child, parturient). Formulation of evidence-based guidelines and RSI standardization may positively influence patient safety in daily anaesthetic practice.
... Functions 147 -- 9.3 Simple Two-Spin Example 147 -- 9.3.1 Dirac Delta Function 150 -- 9.3.2 Imaging Sequence ... ... Susceptibility Producing Structures 611 -- 20.6 Correcting Geometric Distortion 615 -- 21 Random Walks ... ... Design, Artifacts, and Nomenclature 779 -- 26.1 Sequence Design and Imaging Parameters 780 -- 26.1.1 ... ... 785 -- 26.2.1 Single and Multi-Echo Spin Echo Sequences 785 -- 26.2.2 Inversion Recovery 788 -- 26.2.3 ... ... Spin Echo with Phase Encoding Between Echoes 789 -- 26.3 Fast Short TR Imaging Sequences 791 -- 26.3.1 ...
Second edition xxxii, 944 stran : ilustrace ; 29 cm
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- radiologie, nukleární medicína a zobrazovací metody
- NLK Publikační typ
- kolektivní monografie
- MeSH
- crush úvod do anestezie * MeSH
- klinické kompetence * MeSH
- lidé MeSH
- průzkumy a dotazníky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- dopisy MeSH
- komentáře MeSH
This study examined the sequences of the two rRNA (rrn) operons of pathogenic non-cultivable treponemes, comprising 11 strains of T. pallidum ssp. pallidum (TPA), five strains of T. pallidum ssp. pertenue (TPE), two strains of T. pallidum ssp. endemicum (TEN), a simian Fribourg-Blanc strain and a rabbit T. paraluiscuniculi (TPc) strain. PCR was used to determine the type of 16S-23S ribosomal intergenic spacers in the rrn operons from 30 clinical samples belonging to five different genotypes. When compared with the TPA strains, TPc Cuniculi A strain had a 17 bp deletion, and the TPE, TEN and Fribourg-Blanc isolates had a deletion of 33 bp. Other than these deletions, only 17 heterogeneous sites were found within the entire region (excluding the 16S-23S intergenic spacer region encoding tRNA-Ile or tRNA-Ala). The pattern of nucleotide changes in the rrn operons corresponded to the classification of treponemal strains, whilst two different rrn spacer patterns (Ile/Ala and Ala/Ile) appeared to be distributed randomly across species/subspecies classification, time and geographical source of the treponemal strains. It is suggested that the random distribution of tRNA genes is caused by reciprocal translocation between repetitive sequences mediated by a recBCD-like system.
- MeSH
- DNA bakterií chemie genetika MeSH
- fylogeneze MeSH
- genetická variace MeSH
- genom bakteriální MeSH
- genotyp MeSH
- mezerníky ribozomální DNA genetika MeSH
- molekulární sekvence - údaje MeSH
- RNA ribozomální 16S genetika MeSH
- RNA ribozomální 23S genetika MeSH
- rRNA Operon * MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- sekvenční delece MeSH
- Treponema pallidum klasifikace genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nucleic acid sequence complementarity underlies many fundamental biological processes. Although first noticed a long time ago, sequence complementarity between mRNAs and ribosomal RNAs still lacks a meaningful biological interpretation. Here we used statistical analysis of large-scale sequence data sets and high-throughput computing to explore complementarity between 18S and 28S rRNAs and mRNA 3' UTR sequences. By the analysis of 27,646 full-length 3' UTR sequences from 14 species covering both protozoans and metazoans, we show that the computed 18S rRNA complementarity creates an evolutionarily conserved localization pattern centered around the ribosomal mRNA entry channel, suggesting its biological relevance and functionality. Based on this specific pattern and earlier data showing that post-termination 80S ribosomes are not stably anchored at the stop codon and can migrate in both directions to codons that are cognate to the P-site deacylated tRNA, we propose that the 18S rRNA-mRNA complementarity selectively stabilizes post-termination ribosomal complexes to facilitate ribosome recycling. We thus demonstrate that the complementarity between 18S rRNA and 3' UTRs has a non-random nature and very likely carries information with a regulatory potential for translational control.
- MeSH
- 3' nepřekládaná oblast * MeSH
- kodon MeSH
- proteosyntéza fyziologie MeSH
- RNA ribozomální chemie fyziologie MeSH
- terminátorové oblasti (genetika) * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The protein sequences found in nature represent a tiny fraction of the potential sequences that could be constructed from the 20-amino-acid alphabet. To help define the properties that shaped proteins to stand out from the space of possible alternatives, we conducted a systematic computational and experimental exploration of random (unevolved) sequences in comparison with biological proteins. In our study, combinations of secondary structure, disorder, and aggregation predictions are accompanied by experimental characterization of selected proteins. We found that the overall secondary structure and physicochemical properties of random and biological sequences are very similar. Moreover, random sequences can be well-tolerated by living cells. Contrary to early hypotheses about the toxicity of random and disordered proteins, we found that random sequences with high disorder have low aggregation propensity (unlike random sequences with high structural content) and were particularly well-tolerated. This direct structure content/aggregation propensity dependence differentiates random and biological proteins. Our study indicates that while random sequences can be both structured and disordered, the properties of the latter make them better suited as progenitors (in both in vivo and in vitro settings) for further evolution of complex, soluble, three-dimensional scaffolds that can perform specific biochemical tasks.
- MeSH
- cirkulární dichroismus MeSH
- databáze proteinů MeSH
- datové soubory jako téma MeSH
- molekulární modely * MeSH
- nukleární magnetická rezonance biomolekulární MeSH
- peptidová knihovna * MeSH
- proteinové agregáty MeSH
- rekombinantní proteiny chemie izolace a purifikace toxicita MeSH
- rozpustnost MeSH
- sbalování proteinů MeSH
- sekundární struktura proteinů * MeSH
- sekvence aminokyselin MeSH
- výpočetní biologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
DNA G-hairpins are potential key structures participating in folding of human telomeric guanine quadruplexes (GQ). We examined their properties by standard MD simulations starting from the folded state and long T-REMD starting from the unfolded state, accumulating ∼130 μs of atomistic simulations. Antiparallel G-hairpins should spontaneously form in all stages of the folding to support lateral and diagonal loops, with sub-μs scale rearrangements between them. We found no clear predisposition for direct folding into specific GQ topologies with specific syn/anti patterns. Our key prediction stemming from the T-REMD is that an ideal unfolded ensemble of the full GQ sequence populates all 4096 syn/anti combinations of its four G-stretches. The simulations can propose idealized folding pathways but we explain that such few-state pathways may be misleading. In the context of the available experimental data, the simulations strongly suggest that the GQ folding could be best understood by the kinetic partitioning mechanism with a set of deep competing minima on the folding landscape, with only a small fraction of molecules directly folding to the native fold. The landscape should further include non-specific collapse processes where the molecules move via diffusion and consecutive random rare transitions, which could, e.g. structure the propeller loops.
