共查询到20条相似文献,搜索用时 31 毫秒
1.
I P Serova G A Ole?nikova E V Komarov V M Kondrat'ev G V Fridlianskii 《Antibiotiki i khimioterapii͡a》1989,34(4):258-261
Ageing of oleandomycin preparations was studied. Certain biologically inactive components accumulating on storage of the preparations were isolated and investigated. A scheme for ageing of oleandomycin phosphate preparations is described. The scheme includes cleaving up of the water molecule at C11 and cleaving by the epoxide ring at the early stages and hydrolysis by the glycoside bonds at the later stages. 相似文献
2.
IAA oxidase preparations from fresh sweet potato tuber discs oxidized IAA only in the presence of added phenolic cofactors, and the pH optimum for enzyme activity depended on the cofactor used. Ageing of tuber discs, either by aeration in distilled water or by incubation on moist filter paper, resulted in increased peroxidase and phenol-stimulated IAA oxidase activities, as well as the development of IAA oxidase activity in the absence of added cofactors. High phenolase activity of fresh tuber discs decreased considerably with ageing. Phenol-stimulated IAA oxidase activity reached maximal levels before IAA oxidase activity in the absence of added cofactors. Enzyme preparations from aged tuber discs had double pH optima, similar to those previously described for sweet potato root IAA oxidase preparations. IAA in the concentration range 10?4 to 10?2 M inhibited the increase in peroxidase and IAA oxidase activities with ageing. DCP-stimulated IAA oxidase activities in preparations from both fresh and aged sweet potato tuber discs were inhibited by manganous ion. 相似文献
3.
Ageing--the decline in survival and fecundity with advancing age is caused by damage to macromolecules and tissues. Ageing is not a programmed process, in the sense that no genes are known to have evolved specifically to cause damage and ageing. Mechanisms of ageing might therefore not be expected to be as highly conserved between distantly related organisms as are mechanisms of development and metabolism. However, evidence is mounting that modulators of the rate of ageing are conserved over large evolutionary distances. As we discuss in this review, this conservation might stem from mechanisms that match reproductive rate to nutrient supply. 相似文献
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Heat shock response and ageing: mechanisms and applications 总被引:16,自引:0,他引:16
Ageing is associated with a decrease in the ability of cells to cope with environmental challenges. This is due partly to the attenuation of a primordial stress response, the so-called heat shock (HS) response, which induces the expression of heat shock proteins (HSPs), composed of chaperones and proteases. The attenuation of the HS response during ageing may be responsible for the accumulation of damaged proteins as well as abnormal regulation of cell death. Maintenance of the HS response by repeated mild heat stress causes anti-ageing hormetic effects on cells and organisms. Here, we describe the molecular mechanism and the state of the HS response as well as the role of specific HSPs during ageing, and discuss the possibility of hormetic modulation of ageing and longevity by repeated mild stress. 相似文献
6.
Oscar Fernandez‐Capetillo 《EMBO reports》2010,11(1):32-36
Ageing is an unavoidable corollary to being alive; the most intuitive interpretation of ageing being that it is the consequence of progressive body degeneration. In agreement with this, current models propose that ageing occurs through a stepwise accumulation of DNA damage, which ultimately limits the regenerative capacity of tissues. On the other hand, there is increasing evidence that fetal distress can influence the development of disease in adult life, a phenomenon known as ‘intrauterine programming’. The extent to which an intrauterine exposure to DNA damage can compromise lifespan remains unclear. My group has recently generated a murine model of a human syndrome linked to defective DNA repair and observed that these animals age prematurely, but the accumulation of DNA damage is restricted mostly to the embryonic period. Here, I discuss the implications of this finding and propose that ageing can be influenced by fetal distress. 相似文献
7.
Partially purified enzyme preparations of extracts of Vigna seedlings exhibited guaiacol-oxidase activity but not IAA-oxidase activity. However, by ageing the enzyme preparations, or by treating them with H2O2, it was possible to unmask IAA-oxidase activity. Gel filtration of Vigna extracts on Sepharose yielded separate peaks for IAA-oxidase, guaiacol-oxidase and auxin protectors. The appearance of a separate IAA-oxidase peak reflected the overlap of peroxidase and protector; the apparent difference in the migration rate of IAA-oxidase and guaiacol-oxidase activity proved to be an artifact. The data imply that previous reports of differences between peroxidase and IAA oxidase need to be reinvestigated to rule out the possible effect of contamination by endogenous, high MW auxin protectors. A rapid method for removing most of the auxin protectors and thereby unmasking IAA-oxidase activity is described. 相似文献
8.
Serge KibinzaJérémie Bazin Christophe BaillyJill M. Farrant Françoise CorbineauHayat El-Maarouf-Bouteau 《Plant science》2011,181(3):309-315
Ageing induces seed deterioration expressed as the loss of seed vigour and/or viability. Priming treatment, which consists in soaking of seeds in a solution of low water potential, has been shown to reinvigorate aged seeds. We investigate the importance of catalase in oxidation protection during accelerated ageing and repair during subsequent priming treatment of sunflower (Helianthus annuus L.) seeds. Seeds equilibrated to 0.29 g H2O g−1 dry matter (DM) were aged at 35 °C for different durations and then primed by incubation for 7 days at 15 °C in a solution of polyethylene glycol 8000 at −2 MPa. Accelerated ageing affected seed germination and priming treatment reversed partially the ageing effect. The inhibition of catalase by the addition of aminotriazol during priming treatment reduced seed repair indicating that catalase plays a key role in protection and repair systems during ageing. Ageing was associated with H2O2 accumulation as showed by biochemical quantification and CeCl3 staining. Catalase was reduced at the level of gene expression, protein content and affinity. Interestingly, priming induced catalase synthesis by activating expression and translation of the enzyme. Immunocytolocalization of catalase showed that the enzyme co-localized with H2O2 in the cytosol. These results clearly indicate that priming induce the synthesis of catalase which is involved in seed recovery during priming. 相似文献
9.
Neurochemical Research - Ageing is the greatest risk factor for dementia, although physiological ageing by itself does not lead to cognitive decline. In addition to ageing, APOE ε4 is... 相似文献
10.
Niedernhofer LJ Robbins PD 《The international journal of biochemistry & cell biology》2008,40(2):176-180
Ageing is defined by the loss of functional reserve over time, leading to a decreased capacity to maintain homeostasis under stress and increased risk of morbidity and mortality. Ageing is extremely heterogeneous between individuals and even between tissues within an organism, making it challenging to identify the molecular basis of ageing. Much of our current understanding of ageing comes from genetic studies in model organisms seeking genes that either accelerate or decelerate the ageing process. These studies revealed not only causes of ageing, but also signaling mechanisms that both promote and protect against ageing. In all cases, the signaling pathways that influence lifespan are familiar mechanisms that regulate cellular metabolism, growth, proliferation, differentiation and survival. This review highlights the significant overlap in signaling mechanisms implicated in both the cellular response to genotoxic stress and regulation of organism lifespan. 相似文献
11.
Activation of latent phenolase by freezing and thawing occurs in both thylakoid sediments and membrane washings from spinach chloroplasts, while ageing and digitonin treatment activates membrane-bound enzyme only. Disc clectrophoresis reveals that frost converts a soluble, latent phenolase to an active form after its release from the thylakoid membrane. Ageing of membranes containing latent phenolase results in direct liberation of other active forms. There are further active, soluble forms, which are exclusively found in the chloroplast stroma fraction. 相似文献
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Spanò C Buselli R Ruffini Castiglione M Bottega S Grilli I 《Journal of plant physiology》2007,164(4):487-495
Temperature and moisture content are particularly important factors influencing the longevity of seeds, and therefore the ageing of seeds is closely tied to storage conditions. The ageing process is characterised by many physiological and biochemical changes: membranes tend to leak, enzymes lose catalytic activity, and chromosomes accumulate mutations. Since viability loss is also associated with the breakdown of nucleic acids, the aim of the study was to determine whether the damage induced by ageing could be associated with changes in the activity of RNases and nucleases in embryos and endosperms of differently stored wheat seeds. In order to better characterise seed conditions, the damage to membranes during seed ageing was evaluated by measuring the conductivity of the soaking solution during imbibition, and by using the Evans Blue colorant; lipid peroxidation was also recorded. RNases and nucleases were studied by SDS-PAGE and activity staining. Ageing of seeds stored in a dry state involved a progressive loss of membrane integrity, which increased with the degree of ageing, while lipid peroxidation remained unchanged. Changes in nucleolytic enzyme activity were recorded in embryos: a decrease in RNases and an increase in nucleases. In the endosperm compartment there were no significant differences in ribonuclease and nuclease patterns during seed ageing. Moreover, neutral RNases were absent in endosperms of dry seeds and were activated following imbibition. Present studies reveal that embryos and endosperms have different enzymatic patterns, thus highlighting that the two seed compartments age independently. A different nucleolytic pattern was present in seeds of comparable viability and membrane damage, which were stored differently, and nuclease metabolism was subject to regulation according to both ageing and the length of the storage period. 相似文献
14.
J Knapowski K Wieczorowska-Tobis J Witowski 《Journal of physiology and pharmacology》2002,53(2):135-146
Ageing is characterized by a gradual decline in organ functional reserves which reduces the ability to maintain homeostasis under conditions of stress. Introduction of cell culture and molecular biology techniques has provided new experimental tools for the analysis of ageing at the molecular level. During ageing progressive degeneration of cells and loss of regenerative capacity are enhanced and with time the alterations caused by them ultimately lead to death. In this paper the current knowledge of the mechanisms of ageing is summarized. 相似文献
15.
Age is the strongest independent risk factor for the development of osteoarthritis (OA) and for many years this was assumed to be due to repetitive microtrauma of the joint surface over time, the so-called ‘wear and tear’ arthritis. As our understanding of OA pathogenesis has become more refined, it has changed our appreciation of the role of ageing on disease. Cartilage breakdown in disease is not a passive process but one involving induction and activation of specific matrix-degrading enzymes; chondrocytes are exquisitely sensitive to changes in the mechanical, inflammatory and metabolic environment of the joint; cartilage is continuously adapting to these changes by altering its matrix. Ageing influences all of these processes. In this review, we will discuss how ageing affects tissue structure, joint use and the cellular metabolism. We describe what is known about pathways implicated in ageing in other model systems and discuss the potential value of targeting these pathways in OA. 相似文献
16.
Patterns of the degradation of various photosynthetic pigments,proteins and nucleic acids have been studied during the ageingof isolated chloroplasts in the light and dark. Ageing causesdegradation of chlorophylls and carotenoids, but the rate ofdegradation of both pigments was faster during light than duringdark ageing. Carotenoids are degraded much faster than chlorophyllsboth in the light and dark. The relatively greater degradationof carotenoids than chlorophylls in the dark suggests the involvementof some mechanism other than the photodestruction of carotenoidsduring ageing. The rate of decline for the DNA content is appreciablyslower than that of RNA and chloroplast-protein, but the degradationof latter two macromolecules is less than that of the chlorophyllsand carotenoids. (Received October 30, 1978; ) 相似文献
17.
Ageing is widely believed to be a non-adaptive process that results from a decline in the force of natural selection. However, recent studies in Saccharomyces cerevisiae are consistent with the existence of a programme of altruistic ageing and death. We suggest that the similarities between the molecular pathways that regulate ageing in yeast, worms, flies and mice, together with evidence that is consistent with programmed death in salmon and other organisms, raise the possibility that programmed ageing or death can also occur in higher eukaryotes. 相似文献
18.
Meng Hao Hui Zhang Zixin Hu Xiaoyan Jiang Qi Song Xi Wang Jiucun Wang Zuyun Liu Xiaofeng Wang Yi Li Li Jin 《Aging cell》2021,20(12)
Ageing is characterized by degeneration and loss of function across multiple physiological systems. To study the mechanisms and consequences of ageing, several metrics have been proposed in a hierarchical model, including biological, phenotypic and functional ageing. In particular, phenotypic ageing and interconnected changes in multiple physiological systems occur in all ageing individuals over time. Recently, phenotypic age, a new ageing measure, was proposed to capture morbidity and mortality risk across diverse subpopulations in US cohort studies. Although phenotypic age has been widely used, it may overlook the complex relationships among phenotypic biomarkers. Considering the correlation structure of these phenotypic biomarkers, we proposed a composite phenotype analysis (CPA) strategy to analyse 71 biomarkers from 2074 individuals in the Rugao Longitudinal Ageing Study. CPA grouped these biomarkers into 18 composite phenotypes according to their internal correlation, and these composite phenotypes were mostly consistent with prior findings. In addition, compared with prior findings, this strategy exhibited some different yet important implications. For example, the indicators of kidney and cardiovascular functions were tightly connected, implying internal interactions. The composite phenotypes were further verified through associations with functional metrics of ageing, including disability, depression, cognitive function and frailty. Compared to age alone, these composite phenotypes had better predictive performances for functional metrics of ageing. In summary, CPA could reveal the hidden relationships of physiological systems and identify the links between physiological systems and functional ageing metrics, thereby providing novel insights into potential mechanisms underlying human ageing. 相似文献
19.
Telomere dysfunction and stem cell ageing 总被引:1,自引:0,他引:1
Ageing is characterized by a decline in organ maintenance and repair. Adult stem cells contribute to tissue repair and organ maintenance. Thus it is conceivable that ageing is partly due to a decline of stem cell function. At molecular level, ageing is associated with an accumulation of damage affecting DNA, proteins, membranes, and organelles, as well as the formation of insoluble protein aggregates. Telomere shortening represents a cell intrinsic mechanism, which contributes to the accumulation of DNA damage during cellular ageing. Telomere dysfunction in response to critical telomere shortening induces DNA damage checkpoints that lead to cell cycle arrest and/or cell death. Checkpoint responses induced by telomere dysfunction have mostly been studied in somatic cells but there are emerging data on cell intrinsic checkpoints that impair the maintenance and function of adult stem cell in response to telomere dysfunction. Moreover, telomere dysfunction induces alterations in the stem cell environment that limit the function of adult stem cells. In this review we summarize our current knowledge on the role of telomere dysfunction in adult stem cell ageing. 相似文献
20.
衰老是任何生物都无法避免的生理现象,它由多种因素引起,其过程极其复杂.酵母细胞是目前衰老研究领域公认的模式生物,一系列影响衰老的分子作用机理及调控因素的发现均源自于对酵母细胞的研究.自然衰老是酵母细胞的衰老模式之一,由于该衰老过程与其他高等真核细胞(特别是哺乳动物细胞)极为相似,近年来受到广泛关注.全面比较酵母细胞衰老的两种模式,详细介绍自然衰老过程中分子作用机理的研究进展,重点阐述其复杂的自然寿命调控通路,包括卡路里限制以及药物添加对Ras/PKA、Sch9、Tor等营养依赖型调控通路的影响,并展望未来该领域需要解决的重要科学问题,为全面深入了解高等生物,特别是人类自身的衰老机理提供参考. 相似文献