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1.
Febrile states may unmask certain Brugada syndrome patients and precipitate ventricular arrhythmias. Here we describe two patients with COVID-19 who develo 相似文献
2.
采用苗期缺磷和全营养对照处理,以70个中国春—野生亲缘种属二体添加系及中国春为材料,根据苗期表观遗传性状、磷吸收率和利用率相对生物量对其进行耐低磷胁迫能力筛选鉴定和基因染色体定位。结果表明:大麦4H和长穗偃麦草7E染色体上携带有耐低磷胁迫的优异基因;长穗偃麦草6E、黑麦1R和6R、卵穗山羊草4Ug和6Mg、易变山羊草4Sv染色体携带促进小麦根系生长发育的基因;拟斯比尔托山羊草5S和簇毛麦4V染色体分别携带高磷吸收率和磷利用率的基因。通过染色体工程技术,可以将携带耐低磷胁迫基因的外源染色体片段导入普通小麦,为小麦耐低磷胁迫育种和了解植物耐低磷胁迫的分子机理奠定基础。 相似文献
3.
M. S. van Mourik J. F. Velu V. R. Lanting J. Limpens B. J. Bouma J. J. Piek J. Baan J. P. S. Henriques M. M. Vis 《Netherlands heart journal》2020,28(5):280-292
Guidelines suggest using frailty characteristics in the work-up for a transcatheter aortic valve implantation (TAVI). There are many frailty-screening 相似文献
4.
N. H. M. Kooistra M. Abawi M. Voskuil K. Urgel M. Samim F. Nijhoff H. M. Nathoe P. A. F. M. Doevendans S. A. J. Chamuleau G. E. H. Leenders T. Leiner A. C. Abrahams H. B. van der Worp P. Agostoni P. R. Stella 《Netherlands heart journal》2020,28(5):253-265
Transcatheter aortic valve implantation (TAVI) is a safe and effective treatment for inoperable, intermediate- or high-risk patients with severe sympt 相似文献
5.
为了提高黄淮海麦区小麦育种材料的赤霉病抗性,采用分子标记辅助选择的方法,将来自望水白的4个抗赤霉病主效QTL 3B-QTL、4B-QTL、5A-QTL和6B-QTL导入不同的感病背景中,在后代BC1F3和BC1F4株系中评价它们的抗病效应和农艺性状回复情况。结果表明:(1)导入4个抗病QTL株系的平均病小穗率和病粒率分别为12.2%和6.3%,而受体亲本则分别达到59.1%和44.2%,抗病性显著提高;(2)病小穗数和病粒率与穗长及株高极显著负相关,但与可育小穗数、百粒重、旗叶长和旗叶宽等农艺性状指标没有显著相关性。因此,通过导入抗病主效QTL可以显著改善感病材料的抗性,为进一步选育高产抗病品种提供基础材料。不良农艺性状的紧密连锁阻碍着抗赤霉病主效QTL的高效利用,需要通过继续回交或与其他品种杂交来打破这种遗传连锁关系。 相似文献
6.
J. Vendrik J. de Boer W. Zwiers S. A. van Gilst M. Holierook E. V. Chekanova J. S. Henriques J. Baan Jr. 《Netherlands heart journal》2020,28(7):384-386
The current coronavirus disease 2019 (COVID-19) crisis has led to a relative unavailability of anaesthesiological support for non-acute cardiac care. 相似文献
7.
G. C. Verwoert S. T. de Vries N. Bijsterveld A. R. Willems R. vd Borgh J. K. Jongman H. M. C. Kemps J. A. Snoek R. Rienks H. T. Jorstad 《Netherlands heart journal》2020,28(7):391-395
The coronavirus disease 2019 (COVID-19) pandemic has led to preventive measures worldwide. With the decline of infection rates, less stringent restrictions 相似文献
8.
9.
Controlled Cytokinin Production in Transgenic
Tobacco Using a
Copper-Inducible Promoter 总被引:24,自引:4,他引:20
Marian Jane McKenzie Vadim Mett Paul Hugh Stewart Reynolds Paula Elizabeth Jameson 《Plant physiology》1998,116(3):969-977
The cytokinin group of plant hormones regulates aspects of plant growth and development, including the release of lateral buds from apical dominance and the delay of senescence. In this work the native promoter of a cytokinin synthase gene (ipt) was removed and replaced with a Cu-controllable promoter. Tobacco (Nicotiana tabacum L. cv tabacum) transformed with this Cu-inducible ipt gene (Cu-ipt) was morphologically identical to controls under noninductive conditions in almost all lines produced. However, three lines grew in an altered state, which is indicative of cytokinin overproduction and was confirmed by a full cytokinin analysis of one of these lines. The in vitro treatment of morphologically normal Cu-ipt transformants with Cu2+ resulted in delayed leaf senescence and an increase in cytokinin concentration in the one line analyzed. In vivo, inductive conditions resulted in a significant release of lateral buds from apical dominance. The morphological changes seen during these experiments may reflect the spatial aspect of control exerted by this gene expression system, namely expression from the root tissue only. These results confirmed that endogenous cytokinin concentrations in tobacco transformants can be temporally and spatially controlled by the induction of ipt gene expression through the Cu-controllable gene-expression system. 相似文献
10.
Claudia S. Bauer Christoph Plieth Birgit Bethmann Ondina Popescu Ulf-Peter Hansen Wilhelm Simonis Gerald Sch?nknecht 《Plant physiology》1998,117(2):545-557
The divalent cation Sr2+ induced repetitive transient spikes of the cytosolic Ca2+ activity [Ca2+]cy and parallel repetitive transient hyperpolarizations of the plasma membrane in the unicellular green alga Eremosphaera viridis. [Ca2+]cy measurements, membrane potential measurements, and cation analysis of the cells were used to elucidate the mechanism of Sr2+-induced [Ca2+]cy oscillations. Sr2+ was effectively and rapidly compartmentalized within the cell, probably into the vacuole. The [Ca2+]cy oscillations cause membrane potential oscillations, and not the reverse. The endoplasmic reticulum (ER) Ca2+-ATPase blockers 2,5-di-tert-butylhydroquinone and cyclopiazonic acid inhibited Sr2+-induced repetitive [Ca2+]cy spikes, whereas the compartmentalization of Sr2+ was not influenced. A repetitive Ca2+ release and Ca2+ re-uptake by the ER probably generated repetitive [Ca2+]cy spikes in E. viridis in the presence of Sr2+. The inhibitory effect of ruthenium red and ryanodine indicated that the Sr2+-induced Ca2+ release from the ER was mediated by a ryanodine/cyclic ADP-ribose type of Ca2+ channel. The blockage of Sr2+-induced repetitive [Ca2+]cy spikes by La3+ or Gd3+ indicated the necessity of a certain influx of divalent cations for sustained [Ca2+]cy oscillations. Based on these data we present a mathematical model that describes the baseline spiking [Ca2+]cy oscillations in E. viridis. 相似文献
11.
Queirs Jos P. Stevens Darren W. Pinkerton Matthew H. Rosa Rui Duarte Bernardo Baeta Alexandra Ramos Jaime A. Xavier Jos C. 《Hydrobiologia》2022,849(10):2317-2333
Hydrobiologia - Fisheries ecosystem-based management is an important tool for sustainable harvesting of fisheries worldwide. Knowledge of trophic interactions is crucial since changes in trophic... 相似文献
12.
Hemant P. Borase Chandrashekhar D. Patil Rahul K. Suryawanshi Sunil H. Koli Bhavana V. Mohite Giovanni Benelli Satish V. Patil 《Bioprocess and biosystems engineering》2017,40(10):1437-1446
The problem of chemically synthesized nanoproducts motivated scientific community to explore ecofriendly methods of nanosynthesis. Diatoms belong to a group of aquatic, unicellular, photosynthetic microalgae have been scarcely investigated as a source of reducing and capping agents for nanosynthesis of pesticides and antibiotics. The present study reports a novel ecofriendly method for the fabrication of bioactive gold nanoparticles using locally isolated Nitzschia diatoms. The diatom-fabricated gold nanoparticles show characteristic ruby red colored with sharp absorbance peak at 529 nm. Electron microscopy confirmed irregular shape of gold nanoparticles, with average size of 43 nm and zeta potential of −16.8 mV. The effects of gold nanoparticles on diatom viability were investigated using light and electron microscopy. The mechanistic approach to shed light on how diatoms reacted after exposure to gold metal salt revealed that exposure to gold chloride triggers elevated levels of catalase and peroxidase (12.76 and 14.43 unit/mg protein, respectively) to relieve reactive oxygen species (ROS) stress induced by gold salt exposure. Investigation studies on mechanisms behind Nitzschia-mediated gold nanoparticles fabrication outlined the role of diatom proteins, polysaccharides in reduction, and stabilization of nanoparticles as confirmed by FT-IR analysis. Bioactivity of gold nanoparticles was accessed by coupling them with antibiotics (penicillin and streptomycin), which increased their antibacterial activity compared to individual nanoparticles and antibiotics (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). Overall, the present novel phyco-nanotechnological approach is a promising tool to be used as sustainable strategy in green nanotechnology as well as to reduce use of antibiotics in microbial control. 相似文献
13.
Justin F. Shaffer Robert W. Kensler Samantha P. Harris 《The Journal of biological chemistry》2009,284(18):12318-12327
Cardiac myosin-binding protein C (cMyBP-C) is a regulatory protein
expressed in cardiac sarcomeres that is known to interact with myosin, titin,
and actin. cMyBP-C modulates actomyosin interactions in a
phosphorylation-dependent way, but it is unclear whether interactions with
myosin, titin, or actin are required for these effects. Here we show using
cosedimentation binding assays, that the 4 N-terminal domains of murine
cMyBP-C (i.e. C0-C1-m-C2) bind to F-actin with a dissociation
constant (Kd) of ∼10 μm and a molar
binding ratio (Bmax) near 1.0, indicating 1:1 (mol/mol)
binding to actin. Electron microscopy and light scattering analyses show that
these domains cross-link F-actin filaments, implying multiple sites of
interaction with actin. Phosphorylation of the MyBP-C regulatory motif, or
m-domain, reduced binding to actin (reduced Bmax) and
eliminated actin cross-linking. These results suggest that the N terminus of
cMyBP-C interacts with F-actin through multiple distinct binding sites and
that binding at one or more sites is reduced by phosphorylation. Reversible
interactions with actin could contribute to effects of cMyBP-C to increase
cross-bridge cycling.Cardiac myosin-binding protein C
(cMyBP-C)2
is a thick filament accessory protein that performs both structural and
regulatory functions within vertebrate sarcomeres. Both roles are likely to be
essential in deciphering how a growing number of mutations found in the
cMyBP-C gene, i.e. MYBPC3, lead to cardiomyopathies and heart failure
in a substantial number of the world''s population
(1,
2).Considerable progress has recently been made in determining the regulatory
functions of cMyBP-C and it is now apparent that cMyBP-C normally limits
cross-bridge cycling kinetics and is critical for cardiac function
(3-5).
Phosphorylation of cMyBP-C is essential for its regulatory effects because
elimination of phosphorylation sites (serine to alanine substitutions)
abolishes the ability of protein kinase A (PKA) to accelerate cross-bridge
cycling kinetics and blunts cardiac responses to inotropic stimuli
(6). The substitutions further
impair cardiac function, reduce contractile reserve, and cause cardiac
hypertrophy in transgenic mice
(6,
7). By contrast, substitution
of aspartic acids at these sites to mimic constitutive phosphorylation is
benign or cardioprotective
(8).Although a role for cMyBP-C in modulating cross-bridge kinetics is
supported by several transgenic and knock-out mouse models
(6,
7,
9,
10), the precise mechanisms by
which cMyBP-C exerts these effects are not completely understood. For
instance, the unique regulatory motif or “m-domain” of cMyBP-C
binds to the S2 subfragment of myosin in vitro
(11) and binding is abolished
by PKA-mediated phosphorylation of the m-domain
(12). These observations have
led to the idea that (un)binding of the m-domain from myosin S2 mediates
PKA-induced increases in cross-bridge cycling kinetics. Consistent with this
idea, Calaghan and colleagues
(13) showed that S2 added to
transiently permeabilized myocytes increased their contractility, presumably
because added S2 displaced cMyBP-C from binding endogenous S2. However, other
reports indicate that cMyBP-C can influence actomyosin interactions through
mechanisms unrelated to S2 binding, because either purified cMyBP-C
(14) or recombinant N-terminal
domains of cMyBP-C (15)
affected acto-S1 filament sliding velocities and ATPase rates in the absence
of myosin S2. These results thus raise the possibility that interactions with
ligands other than myosin S2, such as actin or myosin S1, contribute to
effects of cMyBP-C on cross-bridge interaction kinetics.The idea that cMyBP-C interacts with actin to influence cross-bridge
cycling kinetics is supported by several studies that implicate the regulatory
m-domain or sequences near it in actin binding
(16-19).
cMyBP-C is a member of the immunoglobulin (Ig) superfamily of proteins and
consists of 11 repeating domains that bear homology to either Ig or
fibronectin-like folds. Domains are numbered sequentially from the N terminus
of cMyBP-C as C0 through C10. The m-domain, a unique sequence of ∼100
amino acids, is located between domains C1 and C2 and is phosphorylated on at
least 3 serine residues by PKA
(12). Although the precise
structure of the m-domain is not known, small angle x-ray scattering data
suggest that it is compact and folded in solution and is thus similar in size
and dimensions to the surrounding Ig domains
(20). Recombinant proteins
encompassing the m-domain and/or a combination of adjacent domains including
C0, C1, C2, and a proline-alanine-rich sequence that links C0 to C1 have been
shown to bind actin (16,
18,
19).The purpose of the present study was to characterize binding interactions
of the N terminus of cMyBP-C with actin and to determine whether interactions
with actin are influenced by phosphorylation of the m-domain. Results
demonstrate that the N terminus of cMyBP-C binds to F-actin and to native thin
filaments with affinities similar to that reported for cMyBP-C binding to
myosin S2 (11). Furthermore,
actin binding was reduced by m-domain phosphorylation, suggesting that
reversible interactions of cMyBP-C with actin could contribute to modulation
of cross-bridge kinetics. 相似文献
14.
15.
R. McSorley 《Journal of nematology》1982,14(4):517-522
A FORTRAN computer program was developed to simulate nematode soil sampling strategies consisting of various numbers of samples per field, with each sample consisting of various numbers of soil cores. The program assumes that the nematode species involved fit a negative binomial distribution. Required input data are estimates of the mean and k values, the number of samples per field and cores per sample in the strategy to be investigated, and the number of times the simulation is to be replicated. Output consists of simulated values of the relative deviation from the mean and standard error to mean ratio, both averaged over all replications. The program was used to compare 150 simulated sampling strategies for Meloidogyne incognita, involving all combinations of two mean values (2.0 and 10.0 la.rvae/10 cm³ soil), three k values (1.35, 0.544, and 0.294), five different numbers of samples per field (1, 2, 4. 10, 20), and five different numbers of cores per sample (1, 2, 4, 10, 20). Simulations resulting from different mean values were similar, but best results were obtained with higher k values and 20 cores per sample. Relatively few 20-core samples were needed to obtain average deviations from the mean of 20-25%. 相似文献
16.
17.
Structural Analysis and Molecular Model of a
Self-Incompatibility RNase from Wild Tomato 总被引:4,自引:0,他引:4
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Simon Parry Ed Newbigin David Craik Kazuo T. Nakamura Antony Bacic David Oxley 《Plant physiology》1998,116(2):463-469
Self-incompatibility RNases (S-RNases) are an allelic series of style glycoproteins associated with rejection of self-pollen in solanaceous plants. The nucleotide sequences of S-RNase alleles from several genera have been determined, but the structure of the gene products has only been described for those from Nicotiana alata. We report on the N-glycan structures and the disulfide bonding of the S3-RNase from wild tomato (Lycopersicon peruvianum) and use this and other information to construct a model of this molecule. The S3-RNase has a single N-glycosylation site (Asn-28) to which one of three N-glycans is attached. S3-RNase has seven Cys residues; six are involved in disulfide linkages (Cys-16-Cys-21, Cys-46-Cys-91, and Cys-166-Cys-177), and one has a free thiol group (Cys-150). The disulfide-bonding pattern is consistent with that observed in RNase Rh, a related RNase for which radiographic-crystallographic information is available. A molecular model of the S3-RNase shows that four of the most variable regions of the S-RNases are clustered on one surface of the molecule. This is discussed in the context of recent experiments that set out to determine the regions of the S-RNase important for recognition during the self-incompatibility response. 相似文献
18.
Melania Balzarolo Sander Engels Anja J. de Jong Katka Franke Timo K. van den Berg Muhammet F. Gulen Andrea Ablasser Edith M. Janssen Bas van Steensel Monika C. Wolkers 《Open biology》2021,11(3)
Nucleic acid sensing through pattern recognition receptors is critical for immune recognition of microbial infections. Microbial DNA is frequently methylated at the N6 position of adenines (m6A), a modification that is rare in mammalian host DNA. We show here how that m6A methylation of 5′-GATC-3′ motifs augments the immunogenicity of synthetic double-stranded (ds)DNA in murine macrophages and dendritic cells. Transfection with m6A-methylated DNA increased the expression of the activation markers CD69 and CD86, and of Ifnβ, iNos and Cxcl10 mRNA. Similar to unmethylated cytosolic dsDNA, recognition of m6A DNA occurs independently of TLR and RIG-I signalling, but requires the two key mediators of cytosolic DNA sensing, STING and cGAS. Intriguingly, the response to m6A DNA is sequence-specific. m6A is immunostimulatory in some motifs, but immunosuppressive in others, a feature that is conserved between mouse and human macrophages. In conclusion, epigenetic alterations of DNA depend on the context of the sequence and are differentially perceived by innate cells, a feature that could potentially be used for the design of immune-modulating therapeutics. 相似文献
19.
Biochemical Analysis of Plant Protection Afforded by a
Nonpathogenic Endophytic Mutant of Colletotrichum
magna 总被引:10,自引:0,他引:10
Regina S. Redman Stanley Freeman David R. Clifton Jed Morrel Gayle Brown Rusty J. Rodriguez 《Plant physiology》1999,119(2):795-804
A nonpathogenic mutant of Colletotrichum magna (path-1) was previously shown to protect watermelon (Citrullus lanatus) and cucumber (Cucumis sativus) seedlings from anthracnose disease elicited by wild-type C. magna. Disease protection was observed in stems of path-1-colonized cucurbits but not in cotyledons, indicating that path-1 conferred tissue-specific and/or localized protection. Plant biochemical indicators of a localized and systemic (peroxidase, phenylalanine ammonia-lyase, lignin, and salicylic acid) “plant-defense” response were investigated in anthracnose-resistant and -susceptible cultivars of cucurbit seedlings exposed to four treatments: (1) water (control), (2) path-1 conidia, (3) wild-type conidia, and (4) challenge conditions (inoculation into path-1 conidia for 48 h and then exposure to wild-type conidia). Collectively, these analyses indicated that disease protection in path-1-colonized plants was correlated with the ability of these plants to mount a defense response more rapidly and to equal or greater levels than plants exposed to wild-type C. magna alone. Watermelon plants colonized with path-1 were also protected against disease caused by Colletotrichum orbiculare and Fusarium oxysporum. A model based on the kinetics of plant-defense activation is presented to explain the mechanism of path-1-conferred disease protection. 相似文献