transition zone

过渡带
  • 文章类型: Journal Article
    背景:肾单位网(NPH)包括一组异质性的遗传性肾纤毛病,其临床特征为进行性肾衰竭。到目前为止,明确诊断仅基于分子检测。这里,我们研究了鼻上皮细胞NPHP1和NPHP4免疫染色的可行性,以确保和加速NPH的诊断。
    方法:使用免疫荧光显微镜(IF)分析86例遗传确定的肾纤毛病变个体的样本的NPHP1定位。还分析了35个个体的亚组的NPHP4定位。进行蛋白质印迹以确认IF结果。
    结果:NPHP1和NPHP4在所有具有致病NPHP1变体的个体中都不存在,包括一个具有纯合错义变体(c.1027G>A;p.Gly343Arg)的个体,以前被分类为未知意义的“变体”。“在具有NPHP4基因型的个体中,我们观察到NPHP4完全缺失,而NPHP1严重降低.通过免疫印迹确认IF结果。与肾纤毛病相关的其他基因的变异对NPHP1/NPHP4表达没有任何影响。在两个遗传上未解决的个体中的异常免疫染色引起了进一步的遗传检查,从而分别对NPHP1和NPHP4中的致病变体进行了遗传诊断。
    结论:患者来源的呼吸道上皮细胞的IF可能有助于通过验证不确定的遗传结果和通过分层的遗传诊断方法来确保和加速肾单位的诊断。此外,我们为NPHP1和NPHP4在一个功能模块中的相互作用提供了体内证据。
    BACKGROUND: Nephronophthisis (NPH) comprises a heterogeneous group of inherited renal ciliopathies clinically characterized by progressive kidney failure. So far, definite diagnosis is based on molecular testing only. Here, we studied the feasibility of NPHP1 and NPHP4 immunostaining of nasal epithelial cells to secure and accelerate the diagnosis of NPH.
    METHODS: Samples of 86 individuals with genetically determined renal ciliopathies were analyzed for NPHP1 localization using immunofluorescence microscopy (IF). A sub-cohort of 35 individuals was also analyzed for NPHP4 localization. Western blotting was performed to confirm IF results.
    RESULTS: NPHP1 and NPHP4 were both absent in all individuals with disease-causing NPHP1 variants including one with a homozygous missense variant (c.1027G > A; p.Gly343Arg) formerly classified as a \"variant of unknown significance.\" In individuals with an NPHP4 genotype, we observed a complete absence of NPHP4 while NPHP1 was severely reduced. IF results were confirmed by immunoblotting. Variants in other genes related to renal ciliopathies did not show any impact on NPHP1/NPHP4 expression. Aberrant immunostaining in two genetically unsolved individuals gave rise for a further genetic workup resulting in a genetic diagnosis for both with disease-causing variants in NPHP1 and NPHP4, respectively.
    CONCLUSIONS: IF of patient-derived respiratory epithelial cells may help to secure and accelerate the diagnosis of nephronophthisis-both by verifying inconclusive genetic results and by stratifying genetic diagnostic approaches. Furthermore, we provide in vivo evidence for the interaction of NPHP1 and NPHP4 in a functional module.
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  • 文章类型: Journal Article
    纤毛,对细胞信号传导和适当的细胞功能至关重要的细胞器,依赖于从细胞质中细致的大分子运输来形成和维持。虽然在传统上,滑膜内运输(IFT)途径一直是有关纤毛发生和纤毛维持的广泛研究的重点,最近的研究强调了一种互补和替代的机制-细胞质中的囊泡辅助运输(VAT)到纤毛运输。尽管它具有潜在的意义,增值税途径在很大程度上仍然没有特征。这篇综述探讨了最近的研究,为活的初级纤毛内囊泡相关的扩散和运输的动力学提供了证据。采用高速超分辨率光学显微镜。此外,我们分析了纤毛中囊泡的空间分布,主要依靠电子显微镜数据。通过仔细检查促进货物运输进入纤毛的增值税途径,特别强调最近的进步和成像数据,我们的目标是通过整合IFT-VAT机制来综合纤毛运输的综合模型。
    The cilium, a pivotal organelle crucial for cell signaling and proper cell function, relies on meticulous macromolecular transport from the cytoplasm for its formation and maintenance. While the intraflagellar transport (IFT) pathway has traditionally been the focus of extensive study concerning ciliogenesis and ciliary maintenance, recent research highlights a complementary and alternative mechanism-vesicle-assisted transport (VAT) in cytoplasm to cilium trafficking. Despite its potential significance, the VAT pathway remains largely uncharacterized. This review explores recent studies providing evidence for the dynamics of vesicle-related diffusion and transport within the live primary cilium, employing high-speed super-resolution light microscopy. Additionally, we analyze the spatial distribution of vesicles in the cilium, mainly relying on electron microscopy data. By scrutinizing the VAT pathways that facilitate cargo transport into the cilium, with a specific emphasis on recent advancements and imaging data, our objective is to synthesize a comprehensive model of ciliary transport through the integration of IFT-VAT mechanisms.
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  • 文章类型: Journal Article
    细胞外囊泡(EV)是亚微米膜结构和细胞间通讯的关键介质。1,2最近的研究强调了纤毛衍生的EV在信号转导中的作用。强调了它们作为含有保守纤毛信号蛋白的生物活性胞外细胞器的重要性.3,4瞬时受体电位(TRP)通道多囊素-2(PKD-2)家族的成员存在于绿藻衣藻和线虫秀丽隐杆线虫5,6的纤毛EV和小鼠胚胎节点的EV中并从人类尿液中分离7,8在秀丽隐杆线虫中,PKD-2在男性特异性EV释放感觉神经元中表达,将纤毛尖端延伸到纤毛孔,并直接将电动汽车释放到环境中。6,9男性以机械刺激的方式释放电动汽车,规范电动汽车货物含量,以应对交配伙伴,并在交配过程中在雌雄同体的外阴角质层上沉积PKD-2::GFP标记的EV。9,10组合,我们的研究结果表明,纤毛EV的释放是一个动态过程.在这里,我们使用延时成像识别控制动态EV脱落的机制。纤毛可以维持PKD-2标记的EV的释放2小时。这种延长释放不需要神经元传递。相反,纤毛内在机制调节PKD-2纤毛膜补充和动态EV释放。驱动蛋白-3运动驱动蛋白样蛋白6(KLP-6)是初始和延长EV释放所必需的,而过渡区蛋白NPHP-4仅用于持续的EV释放。在睫状尖端处动态补充PKD-2是持续EV释放的关键。我们的研究提供了实时纤毛EV释放和支持纤毛作为熟练EV释放平台的机制的全面描述。
    Extracellular vesicles (EVs) are submicron membranous structures and key mediators of intercellular communication.1,2 Recent research has highlighted roles for cilia-derived EVs in signal transduction, underscoring their importance as bioactive extracellular organelles containing conserved ciliary signaling proteins.3,4 Members of the transient receptor potential (TRP) channel polycystin-2 (PKD-2) family are found in ciliary EVs of the green algae Chlamydomonas and the nematode Caenorhabditis elegans5,6 and in EVs in the mouse embryonic node and isolated from human urine.7,8 In C. elegans, PKD-2 is expressed in male-specific EV-releasing sensory neurons, which extend ciliary tips to ciliary pore and directly release EVs into the environment.6,9 Males release EVs in a mechanically stimulated manner, regulate EV cargo content in response to mating partners, and deposit PKD-2::GFP-labeled EVs on the vulval cuticle of hermaphrodites during mating.9,10 Combined, our findings suggest that ciliary EV release is a dynamic process. Herein, we identify mechanisms controlling dynamic EV shedding using time-lapse imaging. Cilia can sustain the release of PKD-2-labeled EVs for 2 h. This extended release doesn\'t require neuronal transmission. Instead, ciliary intrinsic mechanisms regulate PKD-2 ciliary membrane replenishment and dynamic EV release. The kinesin-3 motor kinesin-like protein 6 (KLP-6) is necessary for initial and extended EV release, while the transition zone protein NPHP-4 is required only for sustained EV release. The dynamic replenishment of PKD-2 at the ciliary tip is key to sustained EV release. Our study provides a comprehensive portrait of real-time ciliary EV release and mechanisms supporting cilia as proficient EV release platforms.
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  • 文章类型: Journal Article
    亚热带珊瑚礁拥有热带的动态混合,亚热带,和温带物种,由于海洋变暖引起的物种丰度和分布的变化而发生变化。在这些过渡社区中,生物地理学亲和力有望预测物种组成的变化,预计热带物种的增加和冷亲和力温带物种的减少。了解沿生物地理过渡带的物种种群动态至关重要,特别是对于像海胆这样的栖息地工程师来说,它们可以通过放牧促进生态系统的转移。我们调查了9年(2010-2019年)在澳大利亚东部7个地点(28.196°S至30.95°S)的珊瑚相关亚热带珊瑚礁上海胆的种群动态,受变暖和热浪影响的时期。具体来说,我们调查了温带类群的密度和种群规模结构(Centrostephanusrodgersii,毛竹),亚热带(Tripneustesaustraliae)和热带(Diademaspp。)亲和力。与预期相反,生物地理学亲和力不能解释该地区物种丰度的变化。尽管我们预计热带物种的数量会在其寒冷的范围内增加,热带Diadema物种在所有地点都有所下降。亚热带T.australiae也表现出下降,而温带C.rodgersii的种群在整个研究期间都非常稳定。我们的结果表明,无法仅通过生物地理亲和力来预测该地区海胆种群的时间模式,并且可以提供有关该生物地理过渡带中这些重要草食动物种群动态的关键信息。
    Subtropical reefs host a dynamic mix of tropical, subtropical, and temperate species that is changing due to shifts in the abundance and distribution of species in response to ocean warming. In these transitional communities, biogeographic affinity is expected to predict changes in species composition, with projected increases of tropical species and declines in cool-affinity temperate species. Understanding population dynamics of species along biogeographic transition zones is critical, especially for habitat engineers such as sea urchins that can facilitate ecosystem shifts through grazing. We investigated the population dynamics of sea urchins on coral-associated subtropical reefs at 7 sites in eastern Australia (28.196° S to 30.95° S) over 9 years (2010-2019), a period impacted by warming and heatwaves. Specifically, we investigated the density and population size structure of taxa with temperate (Centrostephanus rodgersii, Phyllacanthus parvispinus), subtropical (Tripneustes australiae) and tropical (Diadema spp.) affinities. Counter to expectation, biogeographic affinity did not explain shifts in species abundances in this region. Although we expected the abundance of tropical species to increase at their cold range boundaries, tropical Diadema species declined across all sites. The subtropical T. australiae also showed declines, while populations of the temperate C. rodgersii were remarkably stable throughout our study period. Our results show that temporal patterns of sea urchin populations in this region cannot be predicted by bio-geographic affinity alone and contribute critical information about the population dynamics of these important herbivores along this biogeographic transition zone.
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  • 文章类型: Journal Article
    背景:确定基于5-氨基乙酰丙酸的光动力疗法(ALA-PDT)治疗宫颈上皮内瘤变2级(CIN2)的长期疗效和安全性,以及ALA-PDT治疗宫颈转化区3型病变的适用性。
    方法:我们纳入了青岛大学附属医院妇科诊断为N2CI的81例患者,收集了2019年1月至2021年1月ALA-PDT后的数据。此外,我们根据11例需要生育的患者的随访数据,分析了ALA-PDT在育龄妇女保留生育力方面的优越性.
    结果:我们的研究结果证实了ALA-PDT对于CIN2治疗的长期疗效,在25-36个月的随访中,总有效率为95.83%(23/24)。此外,宫颈转化区3型改善和人乳头瘤病毒(HPV)阴性有效率分别为69.2%(18/26)和82.4%(14/17),分别。ALA-PDT推荐用于同意宫颈转化区3型的患者。此外,没有原发性不孕症的女性在ALA-PDT治疗CIN2后可能会经历自然怀孕和足月分娩的多个婴儿,满意率≈100%。
    结论:ALA-PDT可用于治疗高度鳞状上皮内病变,尤其是有生育要求的患者。
    BACKGROUND: To determine the long-term efficacy and safety of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) for treating cervical intraepithelial neoplasia grade 2 (CIN2) as well as the suitability of ALA-PDT in treating of cervical lesions divided into cervical transformation zone type 3.
    METHODS: We included 81 patients diagnosed with CIN2 at the Department of Gynecology of the Affiliated Hospital of Qingdao University with data collected between January 2019 and January 2021 following ALA-PDT. Furthermore, we analyzed the superiority of ALA-PDT in fertility preservation among women of childbearing age based on follow-up data from 11 patients with fertility requirements.
    RESULTS: Our findings confirmed the long-term efficacy of ALA-PDT for CIN2 treatment, with an overall efficacy of 95.83 % (23/24) at follow-up of 25-36 months. Moreover, the cervical transformation zone type 3 improvement and human papillomavirus (HPV)-negative efficacy were 69.2 % (18/26) and 82.4 % (14/17), respectively. ALA-PDT is recommended for consenting patients with cervical transformation zone type 3. Additionally, women without primary infertility could experience natural pregnancy and full-term birth of more than one baby following ALA-PDT for CIN2 treatment, with a satisfaction rate of ≈100 %.
    CONCLUSIONS: ALA-PDT is recommendable for treating high-grade squamous intraepithelial lesions, especially in patients with fertility requirements.
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  • 文章类型: Journal Article
    初级纤毛是从各种真核细胞表面突出的天线状结构,并且在它们的膜中有不同的蛋白质组成。这种独特的蛋白质组成是由纤毛基部的过渡区(TZ)的存在维持的。充当睫状膜和质膜之间的扩散屏障。已知纤毛和TZ的缺陷会导致一组疾病,统称为纤毛病,表现出广泛的临床特征,如围生期致死性Meckel综合征(MKS),相对轻度的Joubert综合征(JBTS),和非综合征性肾病(NPHP)。构成TZ的蛋白质可以分为MKS和NPHP模块。MKS模块由几种跨膜蛋白和三种可溶性蛋白组成。最近报道TMEM218在诊断为MKS和JBTS的个体中发生突变。然而,关于在MKS和JBTS中发现的TMEM218突变如何影响纤毛的功能知之甚少。在这项研究中,我们发现纤毛膜蛋白在TMEM218基因敲除细胞中没有定位于纤毛,表明TZ的屏障功能受损。此外,在TMEM218敲除细胞中,JBTS相关TMEM218变体而非MKS相关变体的外源表达恢复了睫状膜蛋白的定位.特别是,当在TMEM218敲除细胞中表达时,在JBTS中发现的TMEM218(R115H)变体能够恢复细胞的屏障功能,而MKS变体TMEM218(R115C)不能。因此,MKS和JBTS个体症状的严重程度似乎与细胞水平的纤毛缺陷程度相关。
    Primary cilia are antenna-like structures protruding from the surface of various eukaryotic cells, and have distinct protein compositions in their membranes. This distinct protein composition is maintained by the presence of the transition zone (TZ) at the ciliary base, which acts as a diffusion barrier between the ciliary and plasma membranes. Defects in cilia and the TZ are known to cause a group of disorders collectively called the ciliopathies, which demonstrate a broad spectrum of clinical features, such as perinatally lethal Meckel syndrome (MKS), relatively mild Joubert syndrome (JBTS), and nonsyndromic nephronophthisis (NPHP). Proteins constituting the TZ can be grouped into the MKS and NPHP modules. The MKS module is composed of several transmembrane proteins and three soluble proteins. TMEM218 was recently reported to be mutated in individuals diagnosed as MKS and JBTS. However, little is known about how TMEM218 mutations found in MKS and JBTS affect the functions of cilia. In this study, we found that ciliary membrane proteins were not localized to cilia in TMEM218-knockout cells, indicating impaired barrier function of the TZ. Furthermore, the exogenous expression of JBTS-associated TMEM218 variants but not MKS-associated variants in TMEM218-knockout cells restored the localization of ciliary membrane proteins. In particular, when expressed in TMEM218-knockout cells, the TMEM218(R115H) variant found in JBTS was able to restore the barrier function of cells, whereas the MKS variant TMEM218(R115C) could not. Thus, the severity of symptoms of MKS and JBTS individuals appears to correlate with the degree of their ciliary defects at the cellular level.
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  • 文章类型: Journal Article
    初级纤毛是来自细胞表面的膜结合延伸,其含有用于感知和传递调节细胞状态和活性的信号的受体。大脑中的初级纤毛比培养细胞或上皮组织上的纤毛更难以接近,因为它们在大脑中突出到深处,神经胶质和神经元过程的密集网络。这里,我们调查了纤毛频率,内部结构,形状,和大的位置,小鼠初级视觉皮层的高分辨率透射电子显微镜体积。纤毛从几乎所有兴奋性和抑制性神经元的细胞体中延伸出来,星形胶质细胞,和少突胶质细胞前体细胞(OPCs),但少突胶质细胞和小胶质细胞不存在。超微结构比较显示,神经元和神经胶质之间的纤毛和微管组织的基部不同。调查纤毛近端特征显示,许多纤毛与突触直接相邻,表明纤毛准备遇到局部释放的信号分子。我们的分析表明,突触接近可能是由于神经纤维中的随机相遇,没有证据表明纤毛会调节突触活动,正如在四部门突触中所预期的那样。在突触附近观察到的细胞类别差异很大程度上是由于外部纤毛长度的差异。神经元和神经胶质纤毛之间的许多关键结构特征不同,影响纤毛的位置和形状,因此,暴露于纤毛外的过程和突触。一起,神经元和神经胶质纤毛内部和周围的超微结构表明,大脑中不同细胞类型的纤毛形成和功能存在差异。
    A primary cilium is a membrane-bound extension from the cell surface that contains receptors for perceiving and transmitting signals that modulate cell state and activity. Primary cilia in the brain are less accessible than cilia on cultured cells or epithelial tissues because in the brain they protrude into a deep, dense network of glial and neuronal processes. Here, we investigated cilia frequency, internal structure, shape, and position in large, high-resolution transmission electron microscopy volumes of mouse primary visual cortex. Cilia extended from the cell bodies of nearly all excitatory and inhibitory neurons, astrocytes, and oligodendrocyte precursor cells (OPCs) but were absent from oligodendrocytes and microglia. Ultrastructural comparisons revealed that the base of the cilium and the microtubule organization differed between neurons and glia. Investigating cilia-proximal features revealed that many cilia were directly adjacent to synapses, suggesting that cilia are poised to encounter locally released signaling molecules. Our analysis indicated that synapse proximity is likely due to random encounters in the neuropil, with no evidence that cilia modulate synapse activity as would be expected in tetrapartite synapses. The observed cell class differences in proximity to synapses were largely due to differences in external cilia length. Many key structural features that differed between neuronal and glial cilia influenced both cilium placement and shape and, thus, exposure to processes and synapses outside the cilium. Together, the ultrastructure both within and around neuronal and glial cilia suggest differences in cilia formation and function across cell types in the brain.
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  • 文章类型: Journal Article
    男性一生都不可避免地受前列腺疾病的困扰。然而,对前列腺疾病发病机制的认识仍然有限。在1960年代,McNeal提出了前列腺区的理论:将前列腺分为三个主要区:过渡区,中央区,和外围区。在过去的50年里,不同前列腺区之间的显著差异已逐渐显现出来。我们总结了前列腺不同区域的最显著差异。第一次,我们提出了“前列腺区明显差异”的概念。已经提出了这种新概念以更好地理解前列腺的不同区域。为探讨前列腺不同区病变的易感性提供了新的思路。尽管有报道称区域之间存在差异,前列腺相关疾病的治疗仍不可知.因此,我们还讨论了“前列腺区明显差异”的临床意义,并强调了前列腺区的必要性。
    Men are inevitably plagued by prostate disease throughout their lives. However, the understanding of the pathogenesis of prostate diseases is still limited. In the 1960s, McNeal proposed the theory of prostate zones: the prostate was divided into three main zones: transition zone, central zone, and peripheral zone. Over the past 50 years, significant differences between different prostate zones have been gradually revealed. We summarized the most significant differences in different zones of the prostate. For the first time, we proposed the \"apparent difference in prostate zones\" concept. This new concept has been proposed to understand the different zones of the prostate better. It also provided new ideas for exploring the susceptibility of lesions in different prostate zones. Despite the reported differences between zones, the treatment of prostate-related diseases remains partition agnostic. Therefore, we also discussed the clinical significance of the \"apparent difference in the prostate zone\" and emphasized the necessity of prostate zones.
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  • 文章类型: Journal Article
    在许多类型的软物质中,都会发生陀螺和金刚石级联双网络相之间的转变,但迄今为止,结构途径和晶体学关系仍不清楚。二嵌段共聚物的切片和视图扫描电子显微镜层析成像可监测材料间分隔表面的演变形状,允许对多数域和少数域进行结构表征。两个三面体可塑介晶以体积相加的方式组合形成单个四面体介晶,同时保留网络拓扑,作为循环的类型,环中中原子的数量,少数域支柱长度,并且将给定的介晶原子连接到其邻居的方向在150nm宽的过渡区(TZ)上发展。[111]DD方向与[110]DG方向一致,使得(111)DD和(110)DG平面限定TZ的边界。选择特定的晶体取向以及过渡区的方向和宽度是为了最小化从一个结构到另一个结构的介原子的变形成本。通过最大化相似块的连续性并最小化整个TZ的域的表面曲率和厚度的变化。这种连贯的连续性的独立,跨过渡区的互连网络对于诸如分级机械桁架的应用是关键的,其中不同的网络对被接合以提供相邻晶粒的不同的机械性质,或者可以用作允许超级充电和放电的纳米级阳极/阴极,前提是网络是连续的并且严格分开的。
    Transitions between gyroid and diamond intercatenated double network phases occur in many types of soft matter, but to date, the structural pathway and the crystallographic relationships remain unclear. Slice and view scanning electron microscopy tomography of a diblock copolymer affords monitoring of the evolving shape of the intermaterial dividing surface, allowing structural characterization of both the majority and minority domains. Two trihedral malleable mesoatoms combine to form a single tetrahedral mesoatom in a volume additive manner while preserving network topology, as the types of loops, the number of mesoatoms in a loop, minority domain strut lengths, and directions that connect a given mesoatom to its neighbors evolve across a 150 nm wide transition zone (TZ). The [111]DD direction is coincident with the [110]DG direction so that the (111)DD and (110)DG planes define the boundaries of the TZ. Selection of the particular crystal orientations and direction and width of the transition zone is to minimize the cost of morphing the mesoatoms from one structure to the other, by maximizing like-block continuity and minimizing the variation of the surface curvature and thickness of the domains across the TZ. Such coherent continuity of the independent, intercatenated networks across the transition zone is critical for applications such as graded mechanical trusses where the pair of different networks are joined to provide different mechanical properties for adjacent grains or could serve as a nanoscale anode/cathode allowing super charging and discharging provided the networks are continuous and rigorously separate.
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  • 文章类型: Journal Article
    水位波动区(WLFZs)是河流-水库系统中的重要过渡界面,作为N2O排放的热点。然而,对水文波动下控制N2O排放的响应模式和机制的理解仍然有限,尤其是在岩溶峡谷水库中,这给N2O通量评估带来了显著的不确定性。土壤样品是从洪家渡(HJD)水库的WLFZs沿水流方向从过渡区(T1和T2)到湖相区(T3,T4和T5)在每个地点的三个高度收集的。这些土柱用于在各种充满水的孔隙空间梯度(WFPS)下进行模拟实验,以研究潜在的N2O通量模式并阐明潜在的机理。我们的结果表明,两个区域之间的养分分布和N2O通量模式存在显着差异,过渡带和湖相带的N2O通量最高,WFPS分别为75%和95%,分别。低海拔地区的土壤养分流失受蓄水持续时间延长的影响。湖相区域较高的N2O通量可归因于人为活动导致的营养水平增加。此外,相关分析表明,土壤容重显著影响所有地点的N2O通量,而NO3和SOC分别促进T1-T2和T4-T5中的N2O排放。很明显,N2O的产生主要有助于过渡区的硝化作用,并受到矿化过程的限制。而反硝化在湖相带占主导地位。值得注意的是,WLFZs的年度N2O外排占HJD水库水-空气界面外排的27%,表明贡献比预期的要低得多。然而,这项研究强调了WLFZs作为N2O排放的重要潜在来源的重要性,特别是在人为活动和高WFPS梯度的影响下。
    The water-level fluctuations zones (WLFZs) are crucial transitional interfaces within river-reservoir systems, serving as hotspots for N2O emission. However, the comprehension of response patterns and mechanisms governing N2O emission under hydrological fluctuation remains limited, especially in karstic canyon reservoirs, which introduces significant uncertainty to N2O flux assessments. Soil samples were collected from the WLFZs of the Hongjiadu (HJD) Reservoir along the water flow direction from transition zone (T1 and T2) to lacustrine zone (T3, T4 and T5) at three elevations for each site. These soil columns were used to conduct simulation experiments under various water-filled pore space gradients (WFPSs) to investigate the potential N2O flux pattern and elucidate the underlying mechanism. Our results showed that nutrient distribution and N2O flux pattern differed significantly between two zones, with the highest N2O fluxes in the transition zone sites and lacustrine zone sites were found at 75 % and 95 % WFPS, respectively. Soil nutrient loss in lower elevation areas is influenced by prolonged impoundment durations. The higher N2O fluxes in the lacustrine zone can be attributed to increased nutrient levels resulting from anthropogenic activities. Furthermore, correlation analysis revealed that soil bulk density significantly impacted N2O fluxes across all sites, while NO3-and SOC facilitated N2O emissions in T1-T2 and T4-T5, respectively. It was evident that N2O production primarily contributed to nitrification in the transition zone and was constrained by the mineralization process, whereas denitrification dominated in the lacustrine zone. Notably, the annual N2O efflux from WLFZs accounted for 27 % of that from the water-air interface in HJD Reservoir, indicating a considerably lower contribution than anticipated. Nevertheless, this study highlights the significance of WLFZs as a vital potential source of N2O emission, particularly under the influence of anthropogenic activities and high WFPS gradient.
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