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811.
Lara Rajeev Karolina Malanowska Jeffrey F. Gardner 《Microbiology and molecular biology reviews》2009,73(2):300-309
Summary: A classical feature of the tyrosine recombinase family of proteins catalyzing site-specific recombination, as exemplified by the phage lambda integrase and the Cre and Flp recombinases, is the ability to recombine substrates sharing very limited DNA sequence identity. Decades of research have established the importance of this short stretch of identity within the core regions of the substrates. Since then, several new enzymes that challenge this paradigm have been discovered and require the role of sequence identity in site-specific recombination to be reconsidered. The integrases of the conjugative transposons such as Tn916, Tn1545, and CTnDOT recombine substrates with heterologous core sequences. The integrase of the mobilizable transposon NBU1 performs recombination more efficiently with certain core mismatches. The integration of CTX phage and capture of gene cassettes by integrons also occur by altered mechanisms. In these systems, recombination occurs between mismatched sequences by a single strand exchange. In this review, we discuss literature that led to the formulation of the current strand-swapping isomerization model for tyrosine recombinases. The review then focuses on recent developments on the recombinases that challenged the paradigm that was derived from the studies of early systems. 相似文献
812.
The functional characterisation of potassium channels found in the mitochondria of plants and unicellular eukaryotes is critically discussed herein, with a focus on the ATP-sensitive potassium channel and the large-conductance Ca2+-activated potassium channel (mitoBKCa channel). The physiological functions of these channels are not completely understood. We discuss the functional connections and roles of potassium channels, uncoupling protein and alternative oxidase, three energy-dissipating systems that exist in the mitochondrial respiratory chain of plants and some unicellular eukaryotes, which include preventing the production of reactive oxygen species. 相似文献
813.
Nitric oxide,hydrogen cyanide and ethylene are required in the control of germination and undisturbed development of young apple seedlings 总被引:1,自引:0,他引:1
Agnieszka Gniazdowska Urszula Krasuska Karolina Czajkowska Renata Bogatek 《Plant Growth Regulation》2010,61(1):75-84
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are emerging as important regulators of plant development
(germination, flowering, senescence), acting as secondary messengers in cooperation with classical phytohormones. Apple seeds
are dormant, unless they undergo a 3 month long cold stratification. Deep dormancy of isolated apple embryos can also be broken
by short pre-treatment with HCN or NO with the effect associated with enhanced ethylene synthesis. Non-dormant embryos germinate
well and young seedlings grown from non-dormant embryos do not exhibit any morphological anomalies, such as asymmetric growth
and greening of cotyledons. One of the aims of this work was to investigate the correlation between RNS- mediated (HCN- and
NO-dependent) dormancy removal and ROS (H2O2 and O2−•) accumulation in the embryos. The beneficial effect of NO and HCN on germination of dormant apple embryos has been associated
with marked increases in H2O2 and O2−• concentration in the embryos at early germination stages. We also analyzed growth of young seedlings developed from embryos
pre-treatment with HCN or NO or exposed to ethylene (ethephone) and its precursor 1-aminocyclopropane-1-carboxylic acid (ACC).
ACC and ethephone removed all morphological anomalies of the seedlings (asymmetric growth and greening of cotyledons) but
the radicle growth was rather slight. We propose that accumulation of ROS provoked by HCN and NO pre-treatment is required
for embryo germination “sensu stricto”, while ethylene is required for post-germination seedling growth. 相似文献
814.
The discovery of microRNAs has brought in another level of intricacy in gene regulation. These microRNAs are small non-coding RNAs that have dual ability to act as repressors or inducers of gene activity. MicroRNAs have been implicated in a wide spectrum of biological processes and their expressions have been found to be dysregulated in several diseases. Recently, microRNAs have emerged as a new area of interest in renal development and pathology. MicroRNA profilings have revealed a number of microRNAs that are specific to the kidney or restricted to certain regions of the organ suggesting possible exclusive roles therein. Recently, knockout studies have shown that these riboregulators are critical for normal renal growth and functional renal system. Individual microRNAs have also been identified in renal disease models including kidney cancers, diabetic nephropathy and polycystic kidney disease. Several mechanisms of modulating microRNA activity have also been introduced in recent years. Further progress in the understanding of microRNA activity, identification of microRNA signatures in different states as well as advancement of microRNA manipulation techniques will be valuable for kidney research. 相似文献
815.
Morgane Kempenaers Martine Roovers Yamina Oudjama Karolina L. Tkaczuk Janusz M. Bujnicki Louis Droogmans 《Nucleic acids research》2010,38(19):6533-6543
Two archaeal tRNA methyltransferases belonging to the SPOUT superfamily and displaying unexpected activities are identified. These enzymes are orthologous to the yeast Trm10p methyltransferase, which catalyses the formation of 1-methylguanosine at position 9 of tRNA. In contrast, the Trm10p orthologue from the crenarchaeon Sulfolobus acidocaldarius forms 1-methyladenosine at the same position. Even more surprisingly, the Trm10p orthologue from the euryarchaeon Thermococcus kodakaraensis methylates the N1-atom of either adenosine or guanosine at position 9 in different tRNAs. This is to our knowledge the first example of a tRNA methyltransferase with a broadened nucleoside recognition capability. The evolution of tRNA methyltransferases methylating the N1 atom of a purine residue is discussed. 相似文献
816.
Aleksandra Wysocka Karolina Mann Henryk Bursig Juliusz Dec Tadeusz S. Gaździk 《Cell and tissue banking》2010,11(2):209-215
Autologous chondrocyte implantation has been shown to be a promising method for treatment of deep articular cartilage defects.
The hyaline cartilage formed by implanted autologous chondrocytes has biomechanical properties similar to those of natural
articular cartilage. Between June 2006 and September 2008 we performed Autologous chondrocyte implantation (ACI) in 50 patients
and the chondrocytes were supported in fibrin glue. The cartilage biopsy samples were taken from the non-weight bearing area
of the patient’s femoral condyle and the samples were transferred to the cell culture laboratory. Chondrocyte were kept in
culture about 20 days. Fibrin glue was used as a three dimensional carrier for chondrocyte implantation. A 450 ml of patient’s
own blood was collected prior to transplantation to produce autologous fibrinogen. Alternatively the allogenic fibrinogen
was prepared from Regional Blood Center voluntary donors. Before surgery the chondrocyte suspension was mixed with fibrin
glue and gel—like fibrograft was prepared. The total number of cells and the size of fibrograft depended on the defect size
in the knee. Our results suggest that ACI technique with fibrin glue is a promising method for treatment of cartilage defect. 相似文献
817.
The review aimed at searching for DNA structure markers of epigenetic modifications leading to intrauterine growth restriction (IUGR) in three livestock species, mouse and human. IUGR affects mammals by harming their wellbeing and the profitability of breeding enterprises. Of the livestock species, we chose cow, pig and sheep owing to there being many reports on the epigenetics of IUGR. IUGR investigations in human and mouse are particularly numerous, as we are interested in our own wellbeing and the mouse is a model species. We decided to focus on five genes (Igf2r, Igf2, H19, Peg3 and Mest) of known IUGR association, reported in all of those species. Despite the abundance of papers on IUGR, naturally occurring mutations responsible for epigenetic modifications have been described only in human and cow. The effect of induced DNA structural modifications upon epigenetics has been described in mouse and pig. One paper regarding mouse was chosen from among those describing DNA modifications performed to obtain parthenogenetic progeny. Papers regarding pig parthenogenetic progeny described the epigenetics of genes involved in foetal development, with no interference with the genome structure. No reports on DNA modifications altering IUGR epigenetics in sheep were found. Only environmental effects were studied and we could not conclude from the experiment designs whether the gene setup could affect the expression of involved genes, as different populations were not included or not specified within particular experiments. Apparently, DNA markers of IUGR epigenetics exist. It has been reported that the small number of them, occurring naturally, may result from neglecting existing evidence of such selection or health status forecasting markers. 相似文献
818.
Terpenes are a widespread group of secondary metabolites that can be found in various family plants such as the Lamiaceae. In view of their numerous valuable biological activities, the industrial production of concrete terpenes and essential oils rich in the substances is intensively studied. Monoterpenes constitute a significant part of the whole group of the aforementioned secondary metabolites. This is due to their numerous biological activities and their ability to permeate the skin. Despite the fact that these substances have gain popularity, they are not comprehensively characterized. The presented review is based on studies of the biological activities of the most important monoterpenes and the essential oils rich in these compounds. The authors focused attention on antioxidant activity, inhibition towards acetyl‐ and butyrylcholinesterase, and α‐amylase and α‐glucosidase, antifungal, hepatoprotective, sedative properties, and their skin permeation enhancement. 相似文献
819.
Victoria T. Hunniford Joshua Montroy Dean A. Fergusson Marc T. Avey Kimberley E. Wever Sarah K. McCann Madison Foster Grace Fox Mackenzie Lafreniere Mira Ghaly Sydney Mannell Karolina Godwinska Avonae Gentles Shehab Selim Jenna MacNeil Lindsey Sikora Emily S. Sena Matthew J. Page Malcolm Macleod David Moher Manoj M. Lalu 《PLoS biology》2021,19(5)
In an effort to better utilize published evidence obtained from animal experiments, systematic reviews of preclinical studies are increasingly more common—along with the methods and tools to appraise them (e.g., SYstematic Review Center for Laboratory animal Experimentation [SYRCLE’s] risk of bias tool). We performed a cross-sectional study of a sample of recent preclinical systematic reviews (2015–2018) and examined a range of epidemiological characteristics and used a 46-item checklist to assess reporting details. We identified 442 reviews published across 43 countries in 23 different disease domains that used 26 animal species. Reporting of key details to ensure transparency and reproducibility was inconsistent across reviews and within article sections. Items were most completely reported in the title, introduction, and results sections of the reviews, while least reported in the methods and discussion sections. Less than half of reviews reported that a risk of bias assessment for internal and external validity was undertaken, and none reported methods for evaluating construct validity. Our results demonstrate that a considerable number of preclinical systematic reviews investigating diverse topics have been conducted; however, their quality of reporting is inconsistent. Our study provides the justification and evidence to inform the development of guidelines for conducting and reporting preclinical systematic reviews.A cross sectional study of a sample of recent preclinical systematic reviews reveals deficiencies in reporting and provides the justification and evidence to inform the development of specific guidelines for conducting and reporting preclinical systematic reviews. 相似文献
820.
Karolina L Tkaczuk Stanislaw Dunin-Horkawicz Elzbieta Purta Janusz M Bujnicki 《BMC bioinformatics》2007,8(1):73