genetic mutant

  • 文章类型: Journal Article
    昼夜节律时钟能够预测从刺胞动物到哺乳动物的动物的日/夜周期。昼夜节律是通过转录-翻译反馈回路(TTFL或起搏器)产生的,CLOCK是动物中保守的积极因素。然而,CLOCK在基础动物中的功能进化起源和作用机制尚不清楚。在cnidarianNematostellavectensis中,起搏器基因转录水平,包括NvClk(时钟直向序列),在持续的黑暗中出现心律失常,质疑NvCLK的作用。利用CRISPR/Cas9,我们产生了NvClk等位基因突变体(NvClkΔ),揭示恒定黑暗(DD)或光(LL)下的昼夜节律行为损失,同时在明暗条件(LD)下保持24小时的节律。转录组学分析显示,与DD条件相比,野生型(WT)息肉在LD中具有不同的节律基因。在LD,NvClkΔ/Δ息肉表现出相当数量的节律基因,但在DD中减少。此外,在LD下,NvClkΔ/Δ息肉表现出颞起搏器基因表达的改变,影响他们潜在的互动。此外,观察到与细胞分裂和神经元分化相关的非节律基因的差异表达。这些发现表明,光响应通路可以部分补偿昼夜节律的中断,时钟基因在刺胞动物中进化,使有节奏的生理和行为与地球生物圈的diel节奏同步。
    The circadian clock enables anticipation of the day/night cycle in animals ranging from cnidarians to mammals. Circadian rhythms are generated through a transcription-translation feedback loop (TTFL or pacemaker) with CLOCK as a conserved positive factor in animals. However, CLOCK\'s functional evolutionary origin and mechanism of action in basal animals are unknown. In the cnidarian Nematostella vectensis, pacemaker gene transcript levels, including NvClk (the Clock ortholog), appear arrhythmic under constant darkness, questioning the role of NvCLK. Utilizing CRISPR/Cas9, we generated a NvClk allele mutant (NvClkΔ), revealing circadian behavior loss under constant dark (DD) or light (LL), while maintaining a 24 hr rhythm under light-dark condition (LD). Transcriptomics analysis revealed distinct rhythmic genes in wild-type (WT) polypsunder LD compared to DD conditions. In LD, NvClkΔ/Δ polyps exhibited comparable numbers of rhythmic genes, but were reduced in DD. Furthermore, under LD, the NvClkΔ/Δ polyps showed alterations in temporal pacemaker gene expression, impacting their potential interactions. Additionally, differential expression of non-rhythmic genes associated with cell division and neuronal differentiation was observed. These findings revealed that a light-responsive pathway can partially compensate for circadian clock disruption, and that the Clock gene has evolved in cnidarians to synchronize rhythmic physiology and behavior with the diel rhythm of the earth\'s biosphere.
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  • 文章类型: Journal Article
    对星状海葵的研究为动物昼夜节律时钟的早期进化提供了重要见解。
    Studies of the starlet sea anemone provide important insights into the early evolution of the circadian clock in animals.
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  • 文章类型: Journal Article
    与哺乳动物不同,斑马鱼再生响应视网膜损伤。因为小胶质细胞被视网膜损伤激活,我们研究了它们在急性或慢性损伤后的再生过程中的作用。在受精后三周(wpf),表现出NMDA诱导的急性神经节和无长突细胞死亡的野生型鱼和具有慢性视锥光感受器变性的淘金(gosh)突变鱼都表现出反应性小胶质细胞/巨噬细胞和Müller胶质细胞增殖。地塞米松治疗的视网膜,为了抑制免疫反应,缺乏反应性小胶质细胞/巨噬细胞,PCNA阳性细胞较少,而LPS处理增加小胶质细胞/巨噬细胞和PCNA标记的细胞。NMDA损伤的视网膜上调il-1β和tnfα促炎细胞因子基因的表达,其次是IL-10和arg1抗炎/重塑细胞因子基因的表达增加。在NMDA损伤的视网膜中可见短暂的早期TNFα促炎小胶质细胞/巨噬细胞群。相比之下,gosh突变视网膜显示促炎细胞因子基因表达略有增加,同时抗炎/重塑细胞因子基因表达增加。在gosh视网膜中很少观察到TNFα促炎小胶质细胞/巨噬细胞。了解为什么急性和慢性损伤导致不同的炎症特征及其对调节斑马鱼视网膜再生的影响将为改善修复受损哺乳动物组织的治疗策略提供重要线索。
    Unlike mammals, zebrafish regenerate in response to retinal damage. Because microglia are activated by retinal damage, we investigated their role during regeneration following either acute or chronic damage. At three weeks post-fertilization (wpf), both wild-type fish exhibiting NMDA-induced acute ganglion and amacrine cell death and gold rush (gosh) mutant fish possessing chronic cone photoreceptor degeneration displayed reactive microglia/macrophages and Müller glia proliferation. Dexamethasone-treated retinas, to inhibit the immune response, lacked reactive microglia/macrophages and possessed fewer PCNA-positive cells, while LPS treatment increased microglia/macrophages and PCNA-labeled cells. NMDA-injured retinas upregulated expression of il-1β and tnfα pro-inflammatory cytokine genes, followed by increased expression of il-10 and arg1 anti-inflammatory/remodeling cytokine genes. A transient early TNFα pro-inflammatory microglia/macrophage population was visualized in NMDA-damaged retinas. In contrast, gosh mutant retinas exhibited a slight increase of pro-inflammatory cytokine gene expression concurrently with a greater increased anti-inflammatory/remodeling cytokine gene expression. Few TNFα pro-inflammatory microglia/macrophages were observed in the gosh retina. Understanding why acute and chronic damage results in different inflammation profiles and their effects on regulating zebrafish retinal regeneration would provide important clues toward improving therapeutic strategies for repairing injured mammalian tissues.
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  • 文章类型: Journal Article
    很有可能获得可观数量的高质量微生物产品,随着航空航天技术的不断进步。微生物的全基因组遗传变异可以由空间微重力和辐射触发。突变率高,突变范围广泛,最终的突变特征是稳定的。因此,空间微生物育种正在发展成为微生物科学中一个新的,有前途的领域,并极大地推动了发酵技术的发展。大量研究发现,暴露于太空后的微生物中发酵潜力有以下改善:(1)发酵周期减少,生长速率增加;(2)混合发酵物种的改善;(3)细菌结合效率和运动性的提高;(4)各种关键酶的生物活性和产品质量的提高;(5)多重不良胁迫抗性的增强;(6)代谢产物的改善,风味,外观,和稳定性。航空航天发酵技术主要有助于微重力环境中的生物加工。与陆地发酵不同,航空航天发酵使细胞悬浮在流体培养基中,而没有明显的剪切力。空间辐射和微重力有物理,化学,以及通过引起流体动力学和基因组交替对突变微生物的生物学效应,转录组,蛋白质组,和代谢组水平。
    It is highly possible to obtain high-quality microbial products in appreciable amounts, as aerospace technology is advancing continuously. Genome-wide genetic variations in microorganisms can be triggered by space microgravity and radiation. Mutation rate is high, mutant range is wide, and final mutant character is stable. Therefore, space microorganism breeding is growing to be a new and promising area in microbial science and has greatly propelled the development of fermentation technology. Numerous studies have discovered the following improvements of fermentation potential in microorganisms after exposure to space: (1) reduction in fermentation cycle and increase in growth rate; (2) improvement of mixed fermentation species; (3) increase in bacterial conjugation efficiency and motility; (4) improvement of the bioactivity of various key enzymes and product quality; (5) enhancement of multiple adverse stress resistance; (6) improvement of fermentation metabolites, flavor, appearance, and stability. Aerospace fermentation technology predominantly contributes to bioprocessing in a microgravity environment. Unlike terrestrial fermentation, aerospace fermentation keeps cells suspended in the fluid medium without significant shear forces. Space radiation and microgravity have physical, chemical, and biological effects on mutant microorganisms by causing alternation in fluid dynamics and genome, transcriptome, proteome, and metabolome levels.
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  • 文章类型: Journal Article
    Barley (Hordeum vulgare L.) is mainly used as animal feed and in malting. In recent years, there has been growing interest in using barley for food production. Starch is the major component of the kernel and may amount up to over 70% of the dry weight. The quality of barley products is much determined by its starch properties such as gelatinization and retrogradation. Starch is also a by-product of the barley fractionation industry and can be utilized for value-added products. This review summarizes the recent developments in our understanding of the isolation, chemical composition, granular structure, chemical structure of starch components, physicochemical properties, and various modifications of barley starch. The structure-function relationships of starch are discussed. This review provides a basis for better utilizing barley starch, as well as the further development of barley as a sustainable crop.
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  • 文章类型: Journal Article
    Unlike mammals, zebrafish have the capacity to regenerate neurons in response to damage. Most zebrafish retinal injury models employ acute damage, which is unlike the chronic, gradual damage that occurs in human retinal diseases. Here, we studied the regenerative response in the zebrafish aipl1b mutant, gold rush (gosh). In gosh mutants, both cones and rods degenerate by 3 weeks post-fertilization (wpf). Müller glia do not exhibit a regenerative response by 3 wpf; however, they do present non-proliferative gliosis. Only at 5 wpf, is proliferation of Müller cells and rod precursor cells activated. Rods start to recover at 5 wpf and by 12 wpf they reach a level of recovery comparable to wild type, but cones remain absent in the adult stage. TNFα was detected in degenerating cones at 5-7 wpf and in Müller glia at 7 wpf in gosh mutants. At 5 wpf, proliferating Müller glia express Sox2, followed by Pax6 expression in neuronal progenitor cells (NPCs), confirming that the neuronal regeneration program is activated in gosh mutants after 5 wpf. Although acute light-induced damage did not activate proliferation of Müller glia, TNFα injection caused Müller glia to commence a proliferative response at 3 wpf in gosh mutants. These results suggest that Müller glia transition from non-proliferative gliosis to a regenerative state in gosh mutants, and that ectopic introduction of TNFα promotes this Müller cell transition even at 3 wpf. Thus, zebrafish gosh mutants provide a useful model to investigate mechanisms underlying retinal regeneration in a chronic photoreceptor degeneration model.
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