Laurates

月桂盐
  • 文章类型: Journal Article
    2-羟基油酸(2-OHOA)作为膜脂质治疗(MLT)抗癌药物而受到关注。然而,从抗癌药物的角度来看,2-OHOA的水溶性差,其有效性仍有改进空间。因此,这项研究旨在通过将2-OHOA配制成脂质体剂型来克服这些问题。此外,在MLT试剂的背景下,2-OHOA对细胞质膜生物物理特性的影响在很大程度上仍未被探索。为了弥合这个差距,我们的研究特别关注治疗前后癌细胞膜流动性和脂质包装特征的变化。利用双光子显微镜和Laurdan荧光探针,我们注意到,脂质体掺入2-OHOA诱导更显著降低癌细胞膜流动性,与未配制的2-OHOA相比,伴随着细胞凋亡率的提高。重要的是,脂质体制剂中2-OHOA的功效增强表明与其胞吞摄取机制相关.总之,我们的发现强调了2-OHOA对癌症质膜的生物物理特性的显着影响,强调脂质体作为2-OHOA在抗癌治疗中的优化递送系统的潜力。
    2-Hydroxyoleic acid (2-OHOA) has gained attention as a membrane lipid therapy (MLT) anti-cancer drug. However, in the viewpoint of anti-cancer drug, 2-OHOA shows poor water solubility and its effectiveness still has space for improvement. Thus, this study aimed to overcome the problems by formulating 2-OHOA into liposome dosage form. Furthermore, in the context of MLT reagents, the influence of 2-OHOA on the biophysical properties of the cytoplasmic membrane remains largely unexplored. To bridge this gap, our study specifically focused the alterations in cancer cell membrane fluidity and lipid packing characteristics before and after treatment. By using a two-photon microscope and the Laurdan fluorescence probe, we noted that liposomes incorporating 2-OHOA induced a more significant reduction in cancer cell membrane fluidity, accompanied by a heightened rate of cellular apoptosis when compared to the non-formulated 2-OHOA. Importantly, the enhanced efficacy of 2-OHOA within the liposomal formulation demonstrated a correlation with its endocytic uptake mechanism. In conclusion, our findings underscore the significant influence of 2-OHOA on the biophysical properties of cancer plasma membranes, emphasizing the potential of liposomes as an optimized delivery system for 2-OHOA in anti-cancer therapy.
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  • 文章类型: Journal Article
    反胶束(RM)是由有机溶剂组成的自发组织的纳米气泡,表面活性剂,和水相,可以封装生物大分子进行各种生物物理研究。与其他RM系统不同,1-癸酰-外消旋-甘油(10MAG)和月桂基二甲胺-N-氧化物(LDAO)表面活性剂体系已被证明比其他RM混合物具有更高的稳定性,对水负载(W0,由水与表面活性剂的比例定义)。我们通过封装三种模型蛋白-细胞色素c来研究这种独特的特性,肌红蛋白,和黄素氧还蛋白-在10MAG/LDAORM中,并应用各种实验方法来表征该系统的行为。我们发现这种表面活性剂体系与传统的,球形,单分散RM种群模型。10MAG/LDAORM在所有条件下都被发现是扁椭圆体,随着W0的增加,表面活性剂重新分布,形成越来越多的球形椭球状颗粒,并带有更多的块状水池。蛋白质独特地影响混合物的热力学,封装在其最佳RM大小,并驱动无蛋白RM大小相应地缩放。这些发现为类似的延展性封装系统的未来发展提供了信息,并为10MAG/LDAORM的应用奠定了基础,以分析纳米级限制下的生物和化学过程。
    Reverse micelles (RMs) are spontaneously organizing nanobubbles composed of an organic solvent, surfactants, and an aqueous phase that can encapsulate biological macromolecules for various biophysical studies. Unlike other RM systems, the 1-decanoyl-rac-glycerol (10MAG) and lauryldimethylamine-N-oxide (LDAO) surfactant system has proven to house proteins with higher stability than other RM mixtures with little sensitivity to the water loading (W0, defined by the ratio of water to surfactant). We investigated this unique property by encapsulating three model proteins - cytochrome c, myoglobin, and flavodoxin - in 10MAG/LDAO RMs and applying a variety of experimental methods to characterize this system\'s behavior. We found that this surfactant system differs greatly from the traditional, spherical, monodisperse RM population model. 10MAG/LDAO RMs were discovered to be oblate ellipsoids at all conditions, and as W0 was increased, surfactants redistributed to form a greater number of increasingly spherical ellipsoidal particles with pools of more bulk-like water. Proteins distinctively influence the thermodynamics of the mixture, encapsulating at their optimal RM size and driving protein-free RM sizes to scale accordingly. These findings inform the future development of similarly malleable encapsulation systems and build a foundation for application of 10MAG/LDAO RMs to analyze biological and chemical processes under nanoscale confinement.
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  • 文章类型: Journal Article
    背景:全球主要的健康问题是细菌耐药性的上升频率。药物组合是对抗耐药细菌的成功策略,可能有助于保护现有药物。单月桂酯是从椰子油中提取的天然化合物,对葡萄球菌具有良好的抗菌活性。金黄色葡萄球菌。这项研究旨在检查单月桂酸酯单独或与β-内酰胺抗生素联合使用对金黄色葡萄球菌分离株的功效。
    方法:采用琼脂稀释法测定单月桂酸酯对金黄色葡萄球菌的最低抑菌浓度(MIC)。用扫描电子显微镜(SEM)检测单月桂酸酯处理后金黄色葡萄球菌的形态变化。进行常规和实时聚合酶链反应(RT-PCR)以检测单月桂酸酯处理后的β-内酰胺酶(blaZ)基因及其表达水平。单月桂酸酯和抗生素的联合治疗通过部分抑制浓度和时间杀伤方法进行评估。
    结果:对115株金黄色葡萄球菌进行了单月桂酸的抗菌活性评估,单月桂酸的MIC为250至2000微克/毫升。SEM显示在存在1xMIC的monolaurin的情况下,金黄色葡萄球菌的外膜中的细胞伸长和溶胀。blaZ基因在金黄色葡萄球菌分离株的73.9%中被发现。RT-PCR显示250和500μg/ml单脂菌素时blaZ基因表达显着降低。通过FIC方法和时间杀伤曲线检测协同作用。联合治疗建立了MIC值的显著降低。抗生素与monolaurin的组合的集体发现表明协同率为83.3%至100%。在消磨时间的研究中,单月桂酸酯和β-内酰胺抗生素的组合产生了协同作用。
    结论:这项研究表明,单月桂酸酯可能是一种抗金黄色葡萄球菌的天然抗菌剂,并且可能是β-内酰胺药物的杰出调节剂。单月桂酸酯和β-内酰胺类抗生素的同时应用,在体外对金黄色葡萄球菌表现出协同作用,有望成为开发特别针对的联合疗法的潜在候选人,几乎无法治愈的细菌感染患者。
    BACKGROUND: A major worldwide health issue is the rising frequency of resistance of bacteria.Drug combinations are a winning strategy in fighting resistant bacteria and might help in protecting the existing drugs.Monolaurin is natural compound extracted from coconut oil and has a promising antimicrobial activity against Staphylococcus.aureus. This study aims to examine the efficacy of monolaurin both individually and in combination with β-lactam antibiotics against Staphylococcus aureus isolates.
    METHODS: Agar dilution method was used for determination of minimum inhibitory concentration (MIC) of monolaurin against S.aureus isolates. Scanning electron microscope (SEM) was used to detect morphological changes in S.aureus after treatment with monolaurin. Conventional and Real-time Polymerase chain reaction (RT-PCR) were performed to detect of beta-lactamase (blaZ) gene and its expressional levels after monolaurin treatment. Combination therapy of monolaurin and antibiotics was assessed through fractional inhibitory concentration and time-kill method.
    RESULTS: The antibacterial activity of monolaurin was assessed on 115 S.aureus isolates, the MIC of monolaurin were 250 to 2000 µg/ml. SEM showed cell elongation and swelling in the outer membrane of S.aureus in the prescence of 1xMIC of monolaurin. blaZ gene was found in 73.9% of S.aureus isolates. RT-PCR shows a significant decrease in of blaZ gene expression at 250 and 500 µg/ml of monolaurin. Synergistic effects were detected through FIC method and time killing curve. Combination therapy established a significant reduction on the MIC value. The collective findings from the antibiotic combinations with monolaurin indicated synergism rates ranging from 83.3% to 100%.In time-kill studies, combination of monolaurin and β-lactam antibiotics produced a synergistic effect.
    CONCLUSIONS: This study showed that monolaurin may be a natural antibacterial agent against S. aureus, and may be an outstanding modulator of β-lactam drugs. The concurrent application of monolaurin and β-lactam antibiotics, exhibiting synergistic effects against S. aureus in vitro, holds promise as potential candidates for the development of combination therapies that target particularly, patients with bacterial infections that are nearly incurable.
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  • 文章类型: Journal Article
    这项研究是为了确定甘油单月桂酸酯和肉桂醛(GCM)补充的混合物对肠道形态的影响,豁免权,蛋鸡的抗氧化状态和盲肠菌群。14周龄健康蛋鸡(Jingfen-1株)1,120只,随机分为4组,每组10个重复28层,各层饲喂含0的日粮(对照组),或250、500和1,000mg/kgGCM,持续12周。结果表明,饲粮添加GCM显著增加肠绒毛高度和绒毛高度/隐窝深度,十二指肠绒毛区,肝脏和空肠中的总超氧化物二尿酶活性,空肠谷胱甘肽过氧化物酶活性,而十二指肠和空肠隐窝深度降低,28周龄蛋鸡肝脏中过氧化氢含量和空肠丙二醛含量(P<0.05)。同时,添加GCM可显著增加20、24和28周龄蛋鸡血清免疫球蛋白A和免疫球蛋白M浓度(P<0.05)。此外,在16SrRNA测序中观察到,添加GCM提高了蛋鸡肠道菌群的丰度和多样性。各组的优势细菌是门水平的类杆菌和厚壁菌,类杆菌和乳酸杆菌是优势属。在蛋鸡日粮中添加GCM改变了盲肠微生物区系的组成和结构。总之,添加GCM(500-1,000mg/kg饮食)可以改善肠道形态,免疫功能,蛋鸡的肠道和肝脏抗氧化状态和肠道菌群,从而提高肠道消化和吸收能力。这些发现为进一步探索GCM改善肠道健康的机制提供了新的途径。
    This study was to determine the effects of the mixture of glycerol monolaurate and cinnamaldehyde (GCM) supplementation on the intestinal morphology, immunity, antioxidant status and cecal microbiota of laying hens. A total of 1,120 healthy laying hens (Jingfen-1 strain) at the age of 14 wk were randomly divided into 4 groups with 10 replicates of 28 layers in each and layers were fed diets containing 0 (control group), or 250, 500, and 1,000 mg/kg GCM for 12 wk. The results showed that dietary supplementation with GCM significantly increased intestinal villus height and villus height/crypt depth, duodenal villus area, total superoxide disumutase activities in the liver and jejunum, jejunal glutathione peroxidase activities while decreased duodenal and jejunal crypt depth, hydrogen peroxide content in the liver and jejunal malondialdehyde content of laying hens aging 28 wk (P < 0.05). Meanwhile, GCM addition significantly increased serum immunoglobulin A and immunoglobulin M concentration of layers at the age of 20, 24, and 28 wk (P < 0.05). Moreover, it was observed in the 16S rRNA sequencing that the addition of GCM elevated the abundance and diversity of gut microbiota in laying hens. The predominant bacteria from each group were Bacteroidota and Firmicutes at the phylum level and Bacteroides and Lactobacillus were the dominant genera. The composition and structure of cecal microflora were changed by the addition of GCM to the diet of laying hens. In conclusion, the addition of GCM (500-1,000 mg/kg diet) can improve intestinal morphology, immune function, intestinal and liver antioxidant status and intestinal flora of laying hens, thereby improving intestinal digestion and absorption capacity. These findings provide a new way to further explore the mechanism of GCM improving intestinal health.
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  • 文章类型: Journal Article
    这项研究的目的是评估不同水平的甘油单月桂酸酯(GML)对产蛋性能的影响,鸡蛋质量,抗氧化能力,后期蛋鸡的肠道形态和免疫功能。将480只Hy-Line品种棕色母鸡(54周龄)随机分配到5个处理组:对照组(基础饮食)和4个GML组(基础饮食中添加100、200、300和400mg/kgGML)。每种处理包括8个重复,每个12只母鸡,并且试验持续8周。结果表明,饮食中包含GML会增加整个实验期间的ADFI以及实验的第5至8周和第1至8周的平均蛋重(线性,P<0.05)。膳食GML添加线性增加蛋白高度,Haugh单位和蛋黄颜色,蛋壳厚度呈二次增加(P<0.05)。血清SOD活性,200mg/kgGML组中的T-AOC和IgG浓度,200和300mg/kgGML组的GSH-Px活性增加,200和300mg/kgGML组MDA浓度较对照组降低(P<0.05)。300mg/kgGML组空肠绒毛高度和绒毛高度:隐窝深度均高于对照组(P<0.05)。脾脏和空肠TLR4、IL-1β和TNF-α的mRNA表达随着饲粮GML浓度的增加而降低(线性,P<0.05)。总之,膳食补充GML可以提高鸡蛋品质,抗氧化能力,后期蛋鸡的肠道形态和免疫功能,建议饮食中包含300mg/kg的GML。
    The objective of this study was to evaluate the effects of different levels of glycerol monolaurate (GML) on laying performance, egg quality, antioxidant capacity, intestinal morphology and immune function in late-phase laying hens. A total of 480 Hy-Line Variety Brown hens (age 54 wk) were randomly assigned to 5 treatments: the control group (basal diet) and 4 GML groups (basal diet supplemented with 100, 200, 300, and 400 mg/kg GML). Each treatment consisted of 8 replicates with 12 hens each and the trial lasted for 8 wk. The results showed that dietary inclusion of GML increased the ADFI in the entire experimental period and the average egg weight in wk 5 to 8 and wk 1 to 8 of the experiment (linear, P < 0.05). Dietary GML addition linearly increased albumen height, Haugh unit and yolk color, and quadratically increased eggshell thickness (P < 0.05). The serum SOD activity, T-AOC and IgG concentrations in the 200 mg/kg GML group, and GSH-Px activity in 200 and 300 mg/kg GML groups were increased, while the MDA concentration in 200 and 300 mg/kg GML groups was decreased than those in the control group (P < 0.05). The jejunal villus height and villus height: crypt depth in 300 mg/kg GML group were higher than that in the control group (P < 0.05). The mRNA expression of TLR4, IL-1β and TNF-α in spleen and jejunum decreased with the increase of dietary GML concentration (linear, P < 0.05). In conclusion, dietary GML supplementation could improve egg quality, antioxidant capacity, intestinal morphology and immune function in late-phase laying hens, and dietary 300 mg/kg GML inclusion is suggested.
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  • 文章类型: Journal Article
    四维(4D)打印为个性化生物医学植入释放了新的潜力,但仍然存在缺乏合适材料的障碍。在这里,我们证明了在低于和高于其相变温度(Ttrans)时具有高弹性的生物可吸收形状记忆弹性体(SME)。这种SME可以通过将十二烷酸甘油酯丙烯酸酯预聚物(pre-PGDA)与丙烯酸单体共聚形成交联的聚(十二烷酸甘油酯丙烯酸酯)(PGDA)-聚丙烯酸(PAA)进行数字光3D打印,或PGDA-PAA网络。印刷的建筑群,具有高分辨率特征的独立式3D结构在生理温度下表现出形状编程特性。通过在55重量%和70重量%之间调整前PGDA的重量比,Ttrans在39.2至47.2℃之间变化,而杨氏模量(E)低于Ttrans40-170MPa,断裂应变(εf)为170%-200%。在Ttrans上方,E降至1-1.82MPa,接近软组织。引人注目的是,仍然保持130-180%的εf。对材料的体外生物相容性测试显示>90%的细胞增殖和巨大的细胞附着。体内血管移植试验强调了这些4D打印构建体在再生主动脉组织中的几何和机械适应性。植入物的生物降解显示出随着时间的推移它们被天然组织完全替代的可能性。为了突出其个性化医疗的潜力,我们打印了患者特异性左心耳(LAA)封堵器,并将其血管内植入体外心脏模型.重要声明:特别为患者设计和制造的4D印刷形状记忆弹性体(SME)植入物在微创手术(MIS)中非常受欢迎。这些植入物中使用的传统形状记忆聚合物通常会遇到不合适的转变温度等问题,生物相容性差,有限的3D设计复杂性,和低韧性,使他们不适合MIS。我们的新中小企业,具有可调的转变温度和增强的韧性,生物相容性和自然可降解,特别是在心血管环境中。这允许植入物,比如生物医学支架,在室温下进行编程,然后在植入后适应身体的生理条件。我们的研究,包括体内血管移植物和体外装置植入,强调SME在主动脉组织再生中的有效性及其在MIS中的应用前景。
    Four-dimensional (4D) printing unlocks new potentials for personalized biomedical implantation, but still with hurdles of lacking suitable materials. Herein, we demonstrate a bioresorbable shape memory elastomer (SME) with high elasticity at both below and above its phase transition temperature (Ttrans). This SME can be digital light 3D printed by co-polymerizing glycerol dodecanoate acrylate prepolymer (pre-PGDA) with acrylic acid monomer to form crosslinked Poly(glycerol dodecanoate acrylate) (PGDA)-Polyacrylic acid (PAA), or PGDA-PAA network. The printed complex, free-standing 3D structures with high-resolution features exhibit shape programming properties at a physiological temperature. By tuning the pre-PGDA weight ratios between 55 wt% and 70 wt%, Ttrans varies between 39.2 and 47.2 ℃ while Young\'s moduli (E) range 40-170 MPa below Ttrans with fractural strain (εf) of 170 %-200 %. Above Ttrans, E drops to 1-1.82 MPa which is close to those of soft tissue. Strikingly, εf of 130-180 % is still maintained. In vitro biocompatibility test on the material shows > 90 % cell proliferation and great cell attachment. In vivo vascular grafting trials underline the geometrical and mechanical adaptability of these 4D printed constructs in regenerating the aorta tissue. Biodegradation of the implants shows the possibility of their full replacement by natural tissue over time. To highlight its potential for personalized medicine, a patient-specific left atrial appendage (LAA) occluder was printed and implanted endovascularly into an in vitro heart model. STATEMENT OF SIGNIFICANCE: 4D printed shape-memory elastomer (SME) implants particularly designed and manufactured for a patient are greatly sought-after in minimally invasive surgery (MIS). Traditional shape-memory polymers used in these implants often suffer from issues like unsuitable transition temperatures, poor biocompatibility, limited 3D design complexity, and low toughness, making them unsuitable for MIS. Our new SME, with an adjustable transition temperature and enhanced toughness, is both biocompatible and naturally degradable, particularly in cardiovascular contexts. This allows implants, like biomedical scaffolds, to be programmed at room temperature and then adapt to the body\'s physiological conditions post-implantation. Our studies, including in vivo vascular grafts and in vitro device implantation, highlight the SME\'s effectiveness in aortic tissue regeneration and its promising applications in MIS.
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  • 文章类型: Journal Article
    简介:兴奋剂和类固醇的使用对动物健康构成严重威胁,甚至可能导致其过早和痛苦的死亡。然而,兴奋剂是一个严重的问题,在今天的动物比赛世界,尤其是在骆驼比赛中。睾酮及其十酯(苯甲酸酯,戊酸盐,异己酸盐,六氢苯甲酸酯,癸酸,十一烷酸酯,月桂酸盐,庚酸盐,cypionate,和己酸盐)是最重要的,因为当它们被施用于动物时,很难有效地测量它们。通常使用尿液和血液测试来确定骆驼和其他动物中的睾丸激素及其酯的水平。本研究的目的是开发和验证液相色谱-质谱(LC-MS/MS)方法,以确定驼毛中的睾酮酯,并应用经验证的方法测定采集样品中的睾酮酯。据我们所知,这是此类研究的第一份报告。结果和讨论:睾酮及其十种衍生物的水平,连同皮质醇-D4内标,为LC-MS/MS分析进行了优化;然而,只有睾酮及其七种酯(即苯甲酸酯,戊酸盐,异己酸盐,六氢苯甲酸酯,癸酸,十一烷酸酯和月桂酸酯)可以在驼毛中得到验证。在骆驼头发样品中只能测定五种睾酮酯;戊酸酯的浓度为10.5-14.9pg/mg(在三头骆驼中),对于六氢苯甲酸酯(六头骆驼),12.5-151.6pg/mg,月桂酸盐(五头骆驼)4.8-32.1pg/mg,5.1pg/mg癸酸酯(在一只骆驼中),和8.35-169pg/mg的睾酮(在所有24头骆驼中)。有趣的是,三只赛马骆驼显示出高浓度的睾丸激素(59.2-169pg/mg,所有三只骆驼),月桂酸盐(4.8-14.5pg/mg,两只骆驼),六氢苯甲酸酯(116pg/mg,一只骆驼),癸酸酯(5.1pg/mg,一只骆驼),和戊酸(11.7pg/mg,一只骆驼)。方法:从AlAin的21头非赛车单峰骆驼和3头赛车骆驼中收集骆驼毛发样本,阿联酋;这些被净化了,粉碎,声处理,并在分析之前提取。采用LC-MS/MS方法测定毛发样品中睾酮酯的水平。结论:这种新颖的驼毛测试程序是准确的,敏感,快速,和强大的。这项研究报告的发现对于评估赛车骆驼的可疑兴奋剂罪行可能具有重要意义。需要进一步的受控睾酮补充研究,以评估个体酯对骆驼健康和疾病以及性能增强水平的影响。这项新的头发测试可以促进兴奋剂控制方面的进一步研究,毒理学,和药理学,以及其他与骆驼健康相关的临床应用,损伤,和疾病。
    Introduction: Doping and steroid use represent a serious threat to animal health and can even lead to their untimely and painful death. However, doping is an acute problem in today\'s animal racing world, particularly in camel racing. Testosterone and its ten esters (benzoate, valerate, isocaproate, hexahydrobenzoate, decanoate, undecanoate, laurate, enanthate, cypionate, and caproate) are of utmost importance, because when they are administered to animals it is difficult to measure them efficiently. The levels of testosterone and its esters in camels and other animals are typically determined using urine and blood tests. The aim of this study was to develop and validate a liquid chromatographic-mass spectrometric (LC-MS/MS) method to determine testosterone esters in camel hair, and to apply the validated method to determine testosterone esters in collected samples. To our knowledge, this is the first report of such research. Results and Discussion: The levels of testosterone and its ten derivatives, along with the cortisol-D4 internal standard, were optimised for LC-MS/MS analysis; however, only testosterone along with its seven esters (namely benzoate, valerate, isocaproate, hexahydrobenzoate, decanoate, undecanoate and laurate) could be validated in camel hair. Only five testosterone esters could be determined in camel hair samples; the concentrations were obtained as 10.5-14.9 pg/mg for valerate (in three camels), 12.5-151.6 pg/mg for hexahydrobenzoate (in six camels), 4.8-32.1 pg/mg for laurate (in five camels), 5.1 pg/mg decanoate (in one camel), and 8.35-169 pg/mg for testosterone (in all 24 camels). Interestingly, the three racing camels displayed high concentrations of testosterone (59.2-169 pg/mg, all three camels), laurate (4.8-14.5 pg/mg, two camels), hexahydrobenzoate (116 pg/mg, one camel), decanoate (5.1 pg/mg, one camel), and valerate (11.7 pg/mg, one camel). Methods: Camel hair samples were collected from 21 non-racing dromedary camels along with three racing camels in Al Ain, UAE; these were decontaminated, pulverised, sonicated, and extracted prior to analysis. An LC-MS/MS method was employed to determine the levels of testosterone esters in the hair samples. Conclusions: This novel camel-hair test procedure is accurate, sensitive, rapid, and robust. The findings reported in this study could be significant to evaluate racing camels for suspected doping offenses. Further controlled testosterone supplementation studies are required to evaluate individual esters\' effects on camel health and diseases and on performance enhancement levels. This new hair test could promote further studies in doping control, toxicology, and pharmacology, as well as having other clinical applications relating to camel health, injury, and disease.
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  • 文章类型: Journal Article
    目的:铜绿假单胞菌是一种机会致病菌,可引起住院和慢性病患者的严重感染。在感染期间,铜绿假单胞菌经历适应性变化以逃避宿主防御和治疗干预,增加死亡率和发病率。脂质结构改变是铜绿假单胞菌分离物在CF慢性肺部感染期间经历的一种这样的改变。研究这种脂质的遗传驱动因素A结构变异对于理解感染期间的铜绿假单胞菌适应至关重要。这里,我们描述了两种具有酰基链位点特异性的脂质A双加氧酶,每个都有不同的进化起源。Further,我们表明,这些酶的功能丧失发生在CF临床分离株,提示潜在的病态适应性表型。研究这些细菌适应提供了对CF气道对在慢性感染期间持续存在的铜绿假单胞菌表型的选择压力的见解。了解这些适应性变化可能最终为临床医生在慢性感染期间更好地控制细菌种群。
    Pseudomonas aeruginosa can survive in a myriad of environments, partially due to modifications of its lipid A, the membrane anchor of lipopolysaccharide. We previously demonstrated that divergent late acyltransferase paralogs, HtrB1 and HtrB2, add acyloxyacyl laurate to lipid A 2- and 2\'-acyl chains, respectively. The genome of P. aeruginosa also has genes which encode two dioxygenase enzymes, LpxO1 and LpxO2, that individually hydroxylate a specific secondary laurate. LpxO1 acts on the 2\'-acyloxyacyl laurate (added by HtrB2), whereas LpxO2 acts on the 2-acyloxyacyl laurate (added by HtrB1) in a site-specific manner. Furthermore, while both enzyme pairs are evolutionarily linked, phylogenomic analysis suggests the LpxO1/HtrB2 enzyme pair as being of ancestral origin, present throughout the Pseudomonas lineage, whereas the LpxO2/HtrB1 enzyme pair likely arose via horizontal gene transfer and has been retained in P. aeruginosa over time. Using a murine pulmonary infection model, we showed that both LpxO1 and LpxO2 enzymes are functional in vivo, as direct analysis of in vivo lipid A structure from bronchoalveolar lavage fluid revealed 2-hydroxylated lipid A. Gene expression analysis reveals increased lpxO2 but unchanged lpxO1 expression in vivo, suggesting differential regulation of these enzymes during infection. We also demonstrate that loss-of-function mutations arise in lpxO1 and lpxO2 during chronic lung infection in people with cystic fibrosis (CF), indicating a potential role for pathogenesis and airway adaptation. Collectively, our study characterizes lipid A 2-hydroxylation during P. aeruginosa airway infection that is regulated by two distinct lipid A dioxygenase enzymes.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen that causes severe infection in hospitalized and chronically ill individuals. During infection, P. aeruginosa undergoes adaptive changes to evade host defenses and therapeutic interventions, increasing mortality and morbidity. Lipid A structural alteration is one such change that P. aeruginosa isolates undergo during chronic lung infection in CF. Investigating genetic drivers of this lipid A structural variation is crucial in understanding P. aeruginosa adaptation during infection. Here, we describe two lipid A dioxygenases with acyl-chain site specificity, each with different evolutionary origins. Further, we show that loss of function in these enzymes occurs in CF clinical isolates, suggesting a potential pathoadaptive phenotype. Studying these bacterial adaptations provides insight into selection pressures of the CF airway on P. aeruginosa phenotypes that persist during chronic infection. Understanding these adaptive changes may ultimately provide clinicians better control over bacterial populations during chronic infection.
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  • 文章类型: Journal Article
    生物膜异质性的研究特别受益于使用环境敏感的荧光探针Laurdan,排放的变化,由任何刺激产生(例如,流动性变化),归因于荧光团附近水合作用的改变。讽刺的是,没有直接测量膜水合水平对Laurdan光谱的影响。为了解决这个问题,我们研究了包埋在固体支持的脂质双层中的Laurdan的荧光光谱与水合作用的关系,并将其与主要的膜流动性调节剂胆固醇的作用进行了比较。效果非常相似,因此,使用该探针获得的结果应谨慎解释。控制光谱变化的主要现象是脂质内部动力学的阻碍。此外,我们揭示了脱水诱导的胆固醇在相分离膜中结构域之间重新分布的有趣机制,这反映了胆固醇的另一种调节功能。
    Studies of biological membrane heterogeneity particularly benefit from the use of the environment-sensitive fluorescent probe Laurdan, for which shifts in the emission, produced by any stimulus (e.g., fluidity variations), are ascribed to alterations in hydration near the fluorophore. Ironically, no direct measure of the influence of the membrane hydration level on Laurdan spectra has been available. To address this, we investigated the fluorescence spectrum of Laurdan embedded in solid-supported lipid bilayers as a function of hydration and compared it with the effect of cholesterol─a major membrane fluidity regulator. The effects are illusively similar, and hence the results obtained with this probe should be interpreted with caution. The dominant phenomenon governing the changes in the spectrum is the hindrance of the lipid internal dynamics. Furthermore, we unveiled the intriguing mechanism of dehydration-induced redistribution of cholesterol between domains in the phase-separated membrane, which reflects yet another regulatory function of cholesterol.
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  • 文章类型: Journal Article
    菠萝叶纤维是一种含有26.9%纤维素的丰富农业废弃物。这项研究的目的是从菠萝叶纤维(PALF-MCC)中制备由聚羟基丁酸酯(PHB)和微晶纤维素制成的完全可降解的绿色生物复合材料。为了提高与PHB的兼容性,使用月桂酰氯作为酯化剂对PALF-MCC进行表面改性。研究了酯化PALF-MCC月桂酸酯含量和膜表面形态变化对生物复合材料性能的影响。通过差示扫描量热法获得的热性能表明,所有生物复合材料的结晶度均降低,100重量%PHB显示最高值,而100重量%酯化的PALF-MCC月桂酸酯显示无结晶度。酯化PALF-MCC月桂酸酯的加入提高了降解温度。当添加5%的PALF-MCC时,表现出最大的拉伸强度和断裂伸长率。结果表明,在生物复合膜中添加酯化的PALF-MCC月桂酸酯作为填料可以保持令人满意的拉伸强度和弹性模量值,而伸长率的略微增加可以帮助增强柔韧性。土壤埋藏试验,具有5-20%(w/w)PALF-MCC月桂酸酯的PHB/酯化PALF-MCC月桂酸酯膜具有比由100%PHB或100%酯化PALF-MCC月桂酸酯组成的膜更高的降解。源自菠萝农业废物的PHB和酯化的PALF-MCC月桂酸酯特别适合于生产在土壤中100%可堆肥的相对低成本的生物复合膜。
    Pineapple leaf fibres are an abundant agricultural waste product that contains 26.9% cellulose. The objective of this study was to prepare fully degradable green biocomposites made of polyhydroxybutyrate (PHB) and microcrystalline cellulose from pineapple leaf fibres (PALF-MCC). To improve compatibility with PHB, the PALF-MCC was surface modified using lauroyl chloride as an esterifying agent. The influence of the esterified PALF-MCC laurate content and changes in the film surface morphology on biocomposite properties was studied. The thermal properties obtained by differential scanning calorimetry revealed a decrease in crystallinity for all biocomposites, with 100 wt% PHB displaying the highest values, whereas 100 wt% esterified PALF-MCC laurate showed no crystallinity. The addition of esterified PALF-MCC laurate increased the degradation temperature. The maximum tensile strength and elongation at break were exhibited when adding 5% of PALF-MCC. The results demonstrated that adding esterified PALF-MCC laurate as a filler in the biocomposite film could retain a pleasant value of tensile strength and elastic modulus whereas a slight increase in elongation can help to enhance flexibility. For soil burial testing, PHB/ esterified PALF-MCC laurate films with 5-20% (w/w) PALF-MCC laurate ester had higher degradation than films consisting of 100% PHB or 100% esterified PALF-MCC laurate. PHB and esterified PALF-MCC laurate derived from pineapple agricultural wastes are particularly suitable for the production of relatively low-cost biocomposite films that are 100% compostable in soil.
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