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851.
白细胞介素1(IL-1)是一种重要的细胞因子,具有广泛的生物学活性。它通过与细胞表面的白细胞介素 1受体(IL-1R)结合而起作用。以杆状病毒为载体在昆虫细胞中克隆表达了小鼠I型可溶性白细胞介素1受体(sIL-1 RI)基因。以NIH/3T3细胞RNA为模板,采用RT-PCR方法扩增得到小鼠sIL-IRI的cDNA,克隆至杆状病毒转移载体pAcGP67B,将转移重组质粒与野生病毒ACNPV DNA共转染昆虫细胞Sf9,经同源重组得到重组杆状病毒rACNPV。应用经纯化的rAcNPV感染昆虫细胞Sf9,表达获得重组的sIL-1RI。经对亲和层析样品的SDS-PAGE分析和对IL-1β生物活性阻断作用实验证实,表达产物能够与其配基结合,并且能够分泌至细胞培养上清中。 相似文献
852.
在表型性状数值分析和AFLP指纹图谱分析的基础上,选取54株斜茎黄芪根瘤菌的代表菌株及已知根瘤菌参比菌株,进行16SrDNA和23SrDNA的PCR-RFLP比较分析。结果表明斜茎黄芪根瘤菌具有极大的系统发育多样性,分别具有24个16SrDNA遗传图谱类型和22个23SrDNA遗传图谱类型,16SrDNA与23SrDNAPCR-RFLP聚类分析树状图谱有较好的一致性,但也存在一些差异。在对较大类群的划分上,它们的结果与表型性状数值分析结果有较好的一致性。将16SrDNA和23SrDNAPCR-RFLP分析数据合并在一起进行分析时,得出26个综合遗传图谱类型和1个综合聚类分析树状图谱。很明显,16SrDNA与23SrDNA的合并,能够得出更可靠的系统发育结论。 相似文献
853.
854.
天然林资源保护工程对长白山林区森林生态系统服务功能的影响 总被引:3,自引:0,他引:3
森林生态系统具有多种服务功能,对生态安全、生物资源和生存环境的保护、实现社会经济可持续发展起着重要的作用。依据国家林业局发布的《森林生态系统服务功能评估规范》(LY/T1721—2008),对涵养水源功能、保育土壤功能、固碳释氧功能、积累营养物质功能、净化大气功能5个方面进行评价,量化揭示天然林资源保护工程实施对长白山林区森林生态系统服务功能物质量及其价值的影响。结果表明:从1998年开始试点,到2010年一期正式结束,森林生态系统各项服务功能的物质量和价值量均呈现增加趋势。在涵养水源功能方面,调节水量增加了657.28×104m3,累计增加价值为113.45亿元;在保育土壤功能方面,固土量增加了4.6×104t,土壤中减少的氮流失0.02×104t,减少的磷流失0.01×104t,减少钾流失0.01×104t,累计增加价值为2.92亿元;在固碳释氧功能方面,固碳量增加了0.64×104t,释氧量增加了0.36×104t,累计增加价值为0.11亿元;在积累营养物质功能方面,固氮量、固磷量、固钾量均增加0.01×104t,累计增加价值0.3亿元;在净化大气功能方面,吸收二氧化硫、氟化物、氮氧化物、滞尘量分别增加24.71×104kg、0.64×104kg、1.08×104kg、1962.76×104kg,累计增加价值5.09亿元。森林生态系统服务功能价值总量增加了121.87亿元,平均每年增加约10亿元,超过工程每年各项投资之和。价值量增加额度依次为:1)涵养水源功能;2)固碳释氧功能;3)保育土壤功能;4)净化大气功能;5)积累营养物质功能。这些增加量只有一部分为工程区当地利用,其余都贡献到全国乃至全球。因此,及时制定和启动生态补偿等一系列政策和措施,将对更好的实施天然林资源保护工程、实现林区的可持续发展具有重要作用。 相似文献
855.
《Saudi Journal of Biological Sciences》2022,29(6):103255
From onset to progression, cancer is a ailment that might take years to grow. All common epithelial malignancies, have a long latency period, frequently 20 years or more, different gene may contain uncountable mutations if they are clinically detectable. MicroRNAs (miRNAs) are around 22nt non-coding RNAs that control gene expression sequence-specifically through translational inhibition or messenger degradation of RNA (mRNA). Epigenetic processes of miRNA control genetic variants through genomic DNA methylation, post-translation histone modification, rework of the chromatin, and microRNAs. The field of miRNAs has opened a new era in understanding small non-coding RNAs since discovering their fundamental mechanisms of action. MiRNAs have been found in viruses, plants, and animals through molecular cloning and bioinformatics approaches. Phytochemicals can invert the epigenetic aberrations, a leading cause of the cancers of various organs, and act as an inhibitor of these changes. The advantage of phytochemicals is that they only function on cells that cause cancer without affecting normal cells. Phytochemicals appear to play a significant character in modulating miRNA expression, which is linked to variations in oncogenes, tumor suppressors, and cancer-derived protein production, according to several studies. In addition to standard anti-oxidant or anti-inflammatory properties, the initial epigenetic changes associated with cancer prevention may be modulated by many polyphenols. In correlation with miRNA and epigenetic factors to treat cancer some of the phytochemicals, including polyphenols, curcumin, resveratrol, indole-3-carbinol are studied in this article. 相似文献
856.
The bulk delta 15 N-value of plant (leaf) biomass is determined by that of the inorganic primary nitrogen sources NO(3)(-), NH(4)(+) and N(2), and by isotope discriminations on their uptake or assimilation. NH(4)(+) from these is transferred into "organic N" mainly by the glutamine synthetase reaction. The involved kinetic nitrogen isotope effect does not become manifest, because the turnover is quantitative. From the product glutamine any further conversion proceeds in a "closed system", where kinetic isotope effects become only efficient in connection with metabolic branching. The central and most important corresponding process is the GOGAT-reaction, involved in the de novo nitrogen binding and in recycling processes like the phenylpropanoid biosynthesis and photorespiration. The reaction yields relatively 15N-depleted glutamate and remaining glutamine, source of 15N-enriched amide-N in heteroaromatic compounds. Glutamate provides nitrogen for all amino acids and some other compounds with different 15N-abundances. An isotope equilibration is not connected to transamination; the relative delta 15 N-value of individual amino acids is determined by their metabolic tasks. Relative to the bulk delta 15 N-value of the plant cell, proteins are generally 15N-enriched, secondary products like chlorophyll, lipids, amino sugars and alkaloids are depleted in 15N. Global delta 15 N-values and 15N-patterns of compounds with several N-atoms can be calculated from those of their precursors and isotope discriminations in their biosyntheses. 相似文献
857.
Petros Ganatsas Marianthi Tsakaldimi Costas Thanos 《Biodiversity and Conservation》2008,17(10):2427-2439
Variation in cone size, seed number per cone, seed potential, seed efficiency, seed morphology and seed germination behavior
of Pinus pinea and its relation to stand conditions was analyzed. Data were collected from P. pinea forest in Strofylia, southern Greece, a forest that belongs to the Natura 2000 European network and the RAMSAR convention
and is characterized by the absence of regeneration for many decades. The pine stands found in the area were distinguished
into five categories according to a previous study and our observations, regarding stand age, canopy cover and the degree
of stress by human pressure. The categories are: (I) young artificial, (II) closed-mature, (III) open-mature, (IV) over-mature
stands and (V) highly degraded stands. Cones were collected from all stand types and their morphological characteristics as
well as their seed production were measured. Seeds were extracted from the collected cones, measured and their germination
behavior was tested. The findings showed that the over-mature and the high degraded stands and to a lesser extent, the closed-mature
stands, produced significantly smaller cones with a lower seed potential, a lower number of filled seeds per cone, a greater
number of not fully developed seeds and reduced seed morphological characteristics than the young and open-mature stands.
However, the seed germination behavior of fully developed seeds was only slightly affected by the stand type. 相似文献
858.
本研究测定了广西龙门岛群桐花树天然林地上部分的生物量。按径阶标准木法分别调查了3种不同年龄阶段天然林的群落生物量,根据18株不同径阶标准木的测定数据,建立了估测群落单株林木地上部各器官生物量的回归方程,方程的相关系数均达极显著水平,估测精度较高,具有实用价值。研究的结果表明,5年、l7年和20年生的桐花树群落地上部生物量分别为3743.5g/m2、7279.0g/m2和8817.1g/m2,年均生产量分别为748.7g/m2·a、428.2g/m2·a和440.9g/m2·a。 相似文献
859.
宝天曼自然保护区植物区系初步研究 总被引:7,自引:0,他引:7
宝天曼自然保护区,位于伏牛山南麓,地处北亚热带向南暖温带过渡区域,植物种类丰富,有高等植物2771种,隶属223科, 1002属。其区系地理成分复杂,有15个分布区类型和17个分布区亚型。通过科属分析,本区植物区系具有以温带成分为主,呈现多方交汇和一定古老性的特点。 相似文献
860.
Abhishek D. Garg Dominika Nowis Jakub Golab Peter Vandenabeele Dmitri V. Krysko Patrizia Agostinis 《生物化学与生物物理学报:癌评论》2010
Immunogenic profile of certain cancer cell death mechanisms has been transmuted by research published over a period of last few years and this change has been so drastic that a new (sub)class of apoptotic cancer cell death, redefined as ‘immunogenic apoptosis’ has started taking shape. In fact, it has been shown that this chemotherapeutic agent-specific immunogenic cancer cell death modality has the capabilities to induce ‘anticancer vaccine effect’, in vivo. These new trends have given an opportunity to combine tumour cell kill and antitumour immunity within a single paradigm, a sort of ‘holy grail’ of anticancer therapeutics. At the molecular level, it has been shown that the immunological silhouette of these cell death pathways is defined by a set of molecules called ‘damage-associated molecular patterns (DAMPs)’. Various intracellular molecules like calreticulin (CRT), heat-shock proteins (HSPs), high-mobility group box-1 (HMGB1) protein, have been shown to be DAMPs exposed/secreted in a stress agent/factor-and cell death-specific manner. These discoveries have motivated further research into discovery of new DAMPs, new pathways for their exposure/secretion, search for new agents capable of inducing immunogenic cell death and urge to solve currently present problems with this paradigm. We anticipate that this emerging amalgamation of DAMPs, immunogenic cell death and anticancer therapeutics may be the key towards squelching cancer-related mortalities, in near future. 相似文献