光生物调节作用的细胞康复机理

光生物调节作用(photobiomodulation,PBM)是激光或单色光(laser irradiation or monochromatic light,LI)对生物系统的非损伤调节作用,包括低强度LI(low intensity LI,LIL)的PBM(uL PBM,LPBM)和中等强度LI(moderate intensity LI,MIL)的PBM(MIL PBM,MPBM).功能内稳态(function-specific homeostasis,FSH)是生物系统维持某种功能稳定发挥的负反馈状态.从FSH的角度可以将PBM分为内稳态PBM(FSH PBM,fPBM)和发展PBM(developmental PBM,dPBM).fPBM只能调节生物系统的功能,但对处于FSH的生物系统无效.dPBM可以打破FSH.LPBM属于fPBM.MPBM由内源性光敏剂所产生的活性氧(reactive oxygen species,ROS)介导,ROS低者属于fPBM,ROS高者属于dPBM.低水平u治疗(low level LI therapy,LLLT)是fPBM的临床应用.只要LI的参数选择合理,LLLT可以实现细胞康复作用.     

盐胁迫下植物细胞离子稳态重建机制

土壤盐渍化是困扰世界粮食产量的一大难题。在盐胁迫环境中,植物获得耐盐能力的一个重要策略是建立新的离子稳态(ionic homeostasis)。盐胁迫下植物细胞离子稳态依赖于膜转运蛋白(泵、载体和离子通道)。利用蛋白质的生化功能分析和突变体功能互补等方法,目前已克隆和鉴定了许多参与离子稳态重建的膜转运蛋白。综述了盐胁迫下植物细胞离子稳态重建的最新研究进展。     

Gadd45α在干细胞DNA损伤中的作用

基因组完整性对于细胞和组织功能至关重要,这种稳态会不断地受到内源性和外源性应激刺激的影响.干细胞对这些应激刺激十分敏感,其DNA会发生不同程度的损伤,诱导干细胞内固有的DNA修复机制.组织特异性干细胞是局部环境中的多能群体,在其整个生命过程中负责维持组织或者系统的完整性.组织特异性干细胞在受到应激刺激之后,能通过某些反...     

瘦素信号与瘦素抵抗机制研究进展

瘦素(leptin)调控机体能量平衡(energy balance)和代谢稳态(metabolic homeostasis)。瘦素功能异常与肥胖和糖尿病等代谢性疾病密切相关。瘦素激活中枢代谢调控神经元,启动瘦素信号转导(leptin signalings),以发挥生理功能。瘦素抵抗(leptin resistance),表现为血浆瘦素水平升高,但作用减弱或消失。目前认为,下丘脑代谢调控神经元的瘦素信号转导异常是瘦素抵抗的主要机制之一。本文综述近五年来瘦素信号转导与瘦素抵抗机制研究进展。     

不同麻醉方法对降低草鱼捕捉应激的作用

正应激(Stress)指生物受到外源或内源刺激后内稳态改变而产生的一系列反应~[1]。在鱼类养殖中,各种操作对鱼产生的惊扰及环境变化均会导致鱼类应激~[2,3]。应激使鱼类代谢强度增加,免疫和生长性能下降~[4,5]。有关人类和哺乳动物的应激研究已积累了大量的资料,相比之下,鱼类应激方面     

中枢神经环路调节骨代谢

骨重塑是维持骨稳态(bone homeostasis)的重要过程，人们通常认为骨重塑主要接受内分泌激素调节。近年来，越来越多的证据表明，中枢神经系统通过传出神经直接参与骨稳态调节。虽然，大脑和骨骼组织之间已被证实存在明确的神经连接，但这些神经联系在大脑调节骨稳态中的作用还不十分清楚。本文将关注骨与脑之间的神经联系，分别从中枢神经系统和神经环路(neural circuit)、自主神经系统以及感觉神经系统对骨稳态的调控等方面介绍大脑调控骨代谢(bone metabolism)领域的最新进展。     

大强度去叶对棉花叶绿素和保护酶系的影响

研究了大强度去叶对棉花叶绿素和保护酶系的影响.结果表明,75%去叶和100%去叶的大强度去叶不会促使棉花产生超补偿现象,而使棉花成铃数分别减少5.4%和9.8%.在短期内大强度去叶可使棉花新生叶片增大、叶绿素含量下降.75%去叶和100%去叶处理还使得棉花叶中蛋白质含量下降,POD酶活性上升、PPO酶活性下降,但POD酶比活力和PPO酶的比活力都上升.说明大强度去叶不仅对植物造成了严重伤害,而且破坏了棉花植株的内稳态平衡.植物不能迅速调整内稳态平衡（homeostasis）恢复元气,最终棉花也不会产生超补偿现象,此时植物处于伤害状态.内稳态变化可能存在信号分子.     

大足黑山羊与萨能奶山羊在发情周期内INH B、ACT A和FSH浓度变化

为了研究发情周期内血浆INH B(Inhibin B)、ACT A(Activin A)和FSH(Follicle stimulating hormone)浓度与山羊繁殖力之间的关系,以高繁殖力的大足黑山羊和低繁殖力的萨能奶山羊为研究对象,采用酶联免疫法(ELISA)测定血浆中INH B、ACTA和FSH浓度,比较两个山羊品种在一个发情周期内血浆中INH B、ACTA和FSH的分泌变化规律.研究结果显示:大足黑山羊和萨能奶山羊血浆中FSH的分泌与ACTA呈正相关,与INH B呈负相关,大足黑山羊在整个发情周期内血浆中的FSH平均浓度高于萨能奶山羊,INH B和ACT A平均浓度均低于萨能奶山羊.从发情症状明显至排卵前这段时问内,大足黑山羊血浆中FSH平均浓度显著高于萨能奶山羊(P＜0.05).结果表明,发情周期内INH B、ACT A与FSH的差异可能是导致大足黑山羊和萨能奶山羊繁殖力差异的根本原因之一.推测ACT A主要作用可能是延长卵泡期,对于山羊排卵个数的影响不起主导作用.INHB可以抑制FSH的水平,从而间接的影响排卵数.     

PERK介导细胞应激反应的分子机制研究进展

内质网应激是未折叠蛋白质在内质网腔内的过量堆积和钙浓度失衡的一种应激反应,不仅参与细胞稳态的维持,而且在调节多种细胞应激反应方面具有重要意义。蛋白激酶R样内质网激酶(PERK)是介导内质网应激的三大关键信号分子之一,在细胞应激反应中具有明确和重要的调控作用。本文就PERK对基因毒应激、代谢应激和炎性应激的调节和分子机制做简要综述。     

内质网应激与心血管疾病关系的研究进展

内质网是蛋白质折叠、转录后修饰和转运的重要细胞器,对维持细胞稳态具有重要作用。多种内外环境刺激能够引起内质网内错误折叠或未折叠蛋白的积累,即形成内质网应激。内质网应激激活未折叠蛋白反应(unfolded protein response,UPR),进而启动一系列下游信号以维持内质网稳态。但持续或过度的内质网应激激活的UPR最终导致细胞凋亡和疾病。近年来,大量研究证据表明,内质网应激参与多种心血管疾病(cardiovascular disease, CVD)的发生和发展,包括缺血性心脏病、糖尿病性心肌病、心力衰竭、动脉粥样硬化、血管钙化、高血压和主动脉瘤等,是治疗多种CVD的重要靶点。本文就内质网应激激活UPR在多种常见CVD中的调控机制以及内质网应激与CVD关系的研究进展作一简要综述。     

Chronoavailability: a theoretical method of studying chronopharmacology

The optimum time of drug administration or the chronestesy of a biosystem can be theoretically determined by the integration of the function: (drug concentration)-(susceptibility of the biosystem) versus time. This integral called chronoavailability could be useful to design experiments for evaluation of chronopharmacologic effects in man.     

Hormonal regulation of spermatogenesis and spermiogenesis

Normal testicular function is dependent upon hormones acting through endocrine and paracrine pathways both in vivo and in vitro. Sertoli cells provide factors necessary for the successful progression of spermatogonia into spermatozoa. Sertoli cells have receptors for follicle stimulating hormone (FSH) and testosterone which are the main hormonal regulators of spermatogenesis. Hormones such as testosterone, FSH and luteinizing hormone (LH) are known to influence the germ cell fate. Their removal induces germ cell apoptosis. Proteins of the Bcl-2 family provide one signaling pathway which appears to be essential for male germ cell homeostasis. In addition to paracrine signals, germ cells also depend upon signals derived from Sertoli by direct membrane contact. Somatostatin is a regulatory peptide playing a role in the regulation of the proliferation of the male gametes. Activin A, follistatin and FSH play a role in germ cell maturation during the period when gonocytes resume mitosis to form the spermatogonial stem cells and differentiating germ cell populations. In vitro cultures systems have provided evidence that spermatogonia in advance stage of differentiation have specific regulatory mechanisms that control their fate. This review article provides an overview of the literature concerning the hormonal pathways regulating spermatogenesis.     

Dynamics of the biological system in turbellarians inhabiting the littoral water bodies of Lake Baikal (Phagocata sibirica) subjected to stress: Model of coupled bistable oscillators

An experimental investigation into the behavior of turbellarians inhabiting the water bodies of the basin of Lake Baikal (Phagocata sibirica (Zabussov, 1903)) under the influence of light, toxicants, and both these factors allows one to find biosystem features under effects other than homeostasis. It is revealed that, when the system is subjected to increasing light intensity, it demonstrates turbulent oscillation with the effects of synchronization and desynchronization. An analysis of the experimental results within the framework of the theory of nonlinear dynamical systems shows that the behavior of the turbellarian biosystem corresponds to the model of coupled bistable oscillators, the synchronization of which is induced by internal biosystem noise.     

Structure and function of bacterial super-biosystem responsible for import and depolymerization of macromolecules

Generally, when microbes assimilate macromolecules, they incorporate low-molecular-weight products derived from macromolecules through the actions of extracellular degrading enzymes. However, a Gram-negative bacterium, Sphingomonas sp. A1, has a smart biosystem for the import and depolymerization of macromolecules. The bacterial cells directly incorporate a macromolecule, alginate, into the cytoplasm through a "superchannel", as we named it. The superchannel consists of a pit on the cell surface, alginate-binding proteins in the periplasm, and an ATP-binding cassette transporter in the inner membrane. Cytoplasmic polysaccharide lyases depolymerize alginate into the constituent monosaccharides. Other than the proteins characterized so far, novel proteins (e.g., flagellin homologs) have been found to be crucial for the import and depolymerization of alginate through genomics- and proteomics-based identification, thus indicating that the biosystem is precisely constructed and regulated by diverse proteins. In this review, we focus on the structure and function of the bacterial biosystem together with the evolution of related proteins.     

The Evolution of the idea of homeostasis: Determinism,stochastics, and chaos–self-organization

Homeostasis is a basic concept in investigating all living systems. Homeostasis and life are synonyms to a certain extent. The concept of homeostasis has been studied and developed for more than 150 years; however, only the 21st century brought us close to understanding homeostasis as a state of a biosystem and a continuous process. The chaos and self-organization theory (CSOT) proves that the conventional views based on determinism (functional analysis) or stochastics (when stochastic uncertainty or certainty occurs) cannot describe homeostasis as defined by W.B. Cannon and his followers. The new CSOT shows a clear boundary between determinism, stochastics (and deterministic chaos), and third-type systems, which have five special properties (principles of self-organization) and can be described in terms of quasiattractors. Kinematics is understood as the motion of quasi-attractors in the phase spaces of states. Complexity is introduced as the rate of evolution of complex biological systems, differing from the definition by Prigogine–Glansdorff. At the same time, concepts of uncertainty of the first and second types and an analog of the Heisenberg calculus are introduced for complexity. According to these concepts, complex biosystems are transferred from the area of traditional science to a new area of the theory of chaos and self-organization.     

Role of Ascorbic Acid in Scavenging Free Radicals and Lead Toxicity from Biosystems

Free radicals are reactive species that are responsible for damaging normal cells and creating diseases in humans. Antioxidants from natural resources or as supplements can scavenge these radicals. A MedLine search indicates that vitamin C is the most investigated antioxidant responsible for the elimination of free radicals. Its chelating property for the removal of neurotoxic lead, which creates oxidative stress in the human biosystem, was investigated and results indicate its great potential as a lead-detoxifying agent.     

The role of calcium in signal transduction processes in Sertoli cells

Sertoli cells play a pivotal role in regulation and maintenance of spermatogenesis. They are hormonally regulated predominantly by follicle-stimulating hormone (FSH) and testosterone (T). Although FSH and T have distinct mechanisms of action they act synergistically in promoting spermatogenesis. Stimulation of freshly isolated Sertoli cells with FSH evokes a prompt rise in cytosolic calcium which is quantitatively reproduced by cAMP. The cytosolic calcium response to FSH in Sertoli cells is predominantly attributable to serial signaling after the generation of endogenous cAMP. Calcium homeostasis of Sertoli cells may also be regulated by cAMP-independent metabolism. Vasoactive testicular paracrine hormones such as angiotensin II (AII) and vasopressin acting via inositol triphosphate generation induce cytosolic calcium rise predominantly derived from the thapsigargin-sensitive endoplasmic reticulum. Investigations involving androgens action on cytosolic calcium reveal a common mechanism of action between the peptide and steroid regulators of Sertoli cell function, indicating that cytosolic calcium ions may represent a unifying biochemical mechanism that could explain the synergism of FSH and T. Androgens rapidly and specifically increase cytosolic calcium, consistent with a plasma membrane site of action. This argues for the possible existence of a short term non-genomic signaling pathway in hormonal regulation of Sertoli cell function in addition to the classical longer term, slower genomic response.     

BIO-RESPONSE TO WHITE NOISE EXCITATION

Pink (1/f-) noise is one of the most common behaviors of biosystems. This paper is devoted to clarifying the stochastic answer given to white-noise excitation of bio-systems.

It is assumed that a living system in general is a bifurcative self-organizing system, and has cyclic symmetry with infinite degrees of freedom, and stationary random stochastic processes characterize their dynamism.

We show that this bifurcation characterizes all levels of bioactivity, and the white-noise excited biosystem has a filter function, and generates a pink-noise spectrum.

Environmental white-noise electromagnetic excitation (like ‘electrosmog’ in general) is filtered by the biosystem, and it gives a characteristic pink-noise answer-signal to this excitation.     

Effect of changes in FSH induced by bovine follicular fluid and FSH infusion in the preovulatory phase on subsequent ovulation rate and corpus luteum function in the ewe

Treatment of Damline ewes with i.v. injections of various doses (2, 5 or 10 ml) of bovine follicular fluid for 72 h after prostaglandin-induced luteal regression resulted in a significant decrease in plasma concentrations of FSH after a 1.5-2 h delay but did not affect LH. The half life of this decrease in plasma FSH levels (156 min) after injection of follicular fluid was similar to that for clearance (159 min) of ovine FSH after infusion. A significant rebound increase in plasma FSH levels occurred by 13 h after all follicular fluid injections, and the magnitude of this rebound was inversely related to the dose of follicular fluid injected. A significant delay in the onset of oestrus occurred only with 5 and 10 ml bovine follicular fluid. There was no significant effect on ovulation rate or subsequent corpus luteum function as measured by plasma concentrations of progesterone. Infusion of ovine FSH (50 micrograms/h for 48 h) during the period of follicular fluid treatment prevented the delay in onset of oestrus and resulted in a substantial (2-10-fold) increase in ovulation rate. Corpus luteum function in terms of progesterone secretion was also enhanced. These results show that (1) intermittent suppression of FSH during the preovulatory period in the ewe does not affect subsequent ovulation rate or corpus luteum function and (2) the delay in the onset of oestrus induced by bovine follicular fluid can be prevented by exogenous FSH.