植物细胞遗传图及其应用

细胞遗传图（cytogenetic map）综合了来自遗传图（genetic map）和细胞学图（cytological map）两方面的信息,它既能反映基因或DNA标记之间在染色体上的真实距离,又能显示它们与染色体的细胞学结构间确切的位置关系。构建植物细胞遗传图的宗旨是将遗传图上的诸多标记与其在染色体的具体位置联系起来。目前主要有两种方法用于细胞遗传图的构建。较广泛使用的一种方法是借助染色体断点来确定遗传标记在染色体上的位置,另一种方法是利用荧光原位杂交（FISH）直接把DNA序列定位到染色体上。此外,利用RN-cM图也可以把遗传标记定位于粗线期染色体。从细胞遗传图可以看出,染色体两臂的远端有较高的基因密度和重组频率。细胞遗传图在比较近缘植物基因组的同线性、揭示植物的进化关系、研究基因定位克隆等方面都有重要意义.     

Enhancement of hormonal stimulation in intact cells. Potentiation of GTP-dependent activation of adenylate cyclase.

The ability of prostaglandin E1 (PGE1) and cholera toxin to increase cyclic AMP levels is potentiated 6-fold when normal rat kidney (NRK) cells are treated with picolinic acid or histidinol, or grown in isoleucine-deficient medium. The response to (-)-isoproterenol is increased 2-fold in NRK cells treated with picolinic acid but not in cells subjected to isoleucine deprivation. The increase in agonist responsiveness is time-dependent, reaches its maximum at 40 h, and is quickly reversed following removal of picolinic acid or addition of medium with normal amounts of isoleucine. The cholera toxin response is also increased about 7-fold in simian virus 40-transformed NRK cells and Moloney sarcoma virus-transformed NRK cells treated with picolinic acid. GTP-stimulated, but not fluoride-stimulated, adenylate cyclase activities are increased in membranes from NRK cells treated with picolinic acid or starved for isoleucine, indicating that the increased response is due, at least in part, to a specific potentiation of GTP-dependent functions of the adenylate cyclase system. The results demonstrate that GTP-dependent events in hormonal stimulation of adenylate cyclase can be altered in intact cells to modulate hormonal enhancement of cyclic AMP production.     

Genetic Enhancement of Memory and Long-Term Potentiation but Not CA1 Long-Term Depression in NR2B Transgenic Rats

One major theory in learning and memory posits that the NR2B gene is a universal genetic factor that acts as rate-limiting molecule in controlling the optimal NMDA receptor''s coincidence-detection property and subsequent learning and memory function across multiple animal species. If so, can memory function be enhanced via transgenic overexpression of NR2B in another species other than the previously reported mouse species? To examine these crucial issues, we generated transgenic rats in which NR2B is overexpressed in the cortex and hippocampus and investigated the role of NR2B gene in NMDA receptor-mediated synaptic plasticity and memory functions by combining electrophysiological technique with behavioral measurements. We found that overexpression of the NR2B subunit had no effect on CA1-LTD, but rather resulted in enhanced CA1-LTP and improved memory performances in novel object recognition test, spatial water maze, and delayed-to-nonmatch working memory test. Our slices recordings using NR2A- and NR2B-selective antagonists further demonstrate that the larger LTP in transgenic hippocampal slices was due to contribution from the increased NR2B-containing NMDARs. Therefore, our genetic experiments suggest that NR2B at CA1 synapses is not designated as a rate-limiting factor for the induction of long-term synaptic depression, but rather plays a crucial role in initiating the synaptic potentiation. Moreover, our studies provide strong evidence that the NR2B subunit represents a universal rate-limiting molecule for gating NMDA receptor''s optimal coincidence-detection property and for enhancing memory function in adulthood across multiple mammalian species.     

Applications of plant-based fermented foods and their microbes

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siRNA的化学修饰和临床应用

RNA干扰（RNAi）是目前分析基因组功能及基因治疗的一个有力工具,引起基因沉默现象的小干扰RNA（siRNA）需要经过适当的化学修饰才能应用于体内。该文总结了既能稳定siRNA双链,又能有效抑制靶基因的几种常用化学修饰法,包括磷酸骨架修饰、核糖修饰和碱基修饰等。正确的修饰将会极大地促进RNAi药物从体外到体内、从实验室到临床应用的转化。siRNA作为一种很有潜力的药物将为治疗病毒性疾病、肿瘤和遗传病开辟一条崭新的道路。     

光生物学与光医学中的新技术及其应用

近几年内,光子生物学与光子医学发展非常快,本文主要从四个方面介绍了近期内在光子生物学与光子医学领城内取得的重要进展：(1)双光子技术,可检测胚胎活组织、确定生物的非损伤激发光阈值、对人体肌纤维进行三维成像;(2)光镊技术,用于研究细胞的应变能力、细胞膜的弹性、跟踪并描述单个分子之间的结合以及操纵DNA分子;(3)光学探针技术,检测疾病、研究构象变化;(4)光学成像技术,主要集中介绍对肌动蛋白的成像方面。     

Hairy Roots, their Multiple Applications and Recent Patents

In the last years, hairy root (HR) cultures are gaining attention in the biotechnology industry. This particular plant cell culture derives from explants infected with Agrobacterium rhizogenes. They constitute a relatively new approach to in vitro plant biotechnology and modern HR cultures are far away from the valuables findings performed by Philip R. White in the 1930?s, who obtained indefinite growth of excised root tips. HR cultures are characterized by genetic and biochemical stability and high growth rate without expensive exogenous hormones source. HR cultures have allowed a deep study of plant metabolic pathways and the production of valuable secondary metabolites and enzymes, with therapeutic or industrial application. Furthermore, the potential of HR cultures is increasing continuously since different biotechnological strategies such as genetic engineering, elicitation and metabolic traps are currently being explored for discovery of new metabolites and pathways, as well as for increasing metabolites biosynthesis and/or secretion. Advances in design of proper bioreactors for HR growth are being of great interest, since scale up of metabolite production will allow the integration of this technology to industrial processes. Another application of HR cultures is related to their capabilities to biotransform and to degrade different xenobiotics. In this context, removal assays using this plant model system are useful tools for phytoremediation assays, previous to the application in the field. This review highlights the more recent application of HRs and those new patents which show their multiple utilities.     

Potentiation of radiation-induced bacterial cell killing by binuclear rhodium(II) complexes and their amines

Rhodium(II) binuclear complexes were surveyed for potentiation of radiation-induced cell killing of hypoxic and fully oxic Salmonella typhimurium cells. The Rh2 tetracarbonate ion substantially potentiated hypoxic cell radiation sensitivity. Phosphate interfered with this potentiation. In the latter two respects, radiation potentiation by Rh2 tetracarbonate is similar to that found for Rh2 tetracarboxylates. Amines such as ammonia, methylamine, ethylamine, n-propylamine, and n-butylamine were examined with both Rh2 tetracarbonate and tetraacetate complexes. With Rh2 tetraacetate in phosphate-buffered saline, these amines variably increased radiation potentiation to a maximum of nearly that seen by Rh2 tetraacetate alone in the absence of phosphate. With Rh2 tetracarbonate, particular amines were found to either enhance or restrict radiation potentiation. Results as a whole support the hypothesis that a radiolytic Rh species initiated in a one-electron reduction process external to the cell is responsible for the potentiation by Rh2 complexes in bacteria. Phosphate interference of potentiation by Rh2 tetracetate appears to be limited competitively by amines, suggesting that axial associations of phosphate with the Rh2 center may be involved in the inhibition of radiation potentiation. Of interest in this regard is the finding that 5'-adenosinemonophosphate eliminates the potentiation seen with Rh2 tetraacetate.     

Clinical Chronobiology and Chronotherapeutics with Applications to Asthma

The concept of homeostasis (i.e., constancy of the milieu interne) has long dominated the teaching and practice of medicine. Concepts and findings from chronobiology, the scientific study of biological rhythms, challenge this construct. Biological processes and functions are not at all constant; rather, they are organized in time as rhythms with period lengths that range in duration from as short as a second or less to as long as a year. It is the body's circadian (24h) rhythms that have been researched most intensely. The peak and trough of these rhythms are ordered rather precisely in time to support the biological requirements of activity during the day and sleep at night. The timing of the peak and trough plus the magnitude of variation (amplitude) of physiological and biochemical functions during the 24h give rise to predictable-in-time, day-night patterns in the manifestation and exacerbation of many common medical conditions. Circadian rhythms also can influence the response of patients to diagnostic tests and therapeutic interventions according to their timing with reference to body rhythms. Rhythms in the pathophysiology of medical conditions and patient tolerance to medications constitute the basis for chronotherapeutics, the timing of treatment in relation to biological rhythm determinants as a means of optimizing beneficial effects and safety. The article discusses recent advances in medical chronobiology and chronotherapeutics and their relevance to clinical medicine in general and the management of asthma in particular. Indeed, since asthma is a disease that exhibits rather profound circadian rhythmicity, investigation of its pathophysiology and therapy necessitates a chronobiologic approach.     

Clinical Chronobiology and Chronotherapeutics with Applications to Asthma

The concept of homeostasis (i.e., constancy of the milieu interne) has long dominated the teaching and practice of medicine. Concepts and findings from chronobiology, the scientific study of biological rhythms, challenge this construct. Biological processes and functions are not at all constant; rather, they are organized in time as rhythms with period lengths that range in duration from as short as a second or less to as long as a year. It is the body's circadian (24h) rhythms that have been researched most intensely. The peak and trough of these rhythms are ordered rather precisely in time to support the biological requirements of activity during the day and sleep at night. The timing of the peak and trough plus the magnitude of variation (amplitude) of physiological and biochemical functions during the 24h give rise to predictable-in-time, day-night patterns in the manifestation and exacerbation of many common medical conditions. Circadian rhythms also can influence the response of patients to diagnostic tests and therapeutic interventions according to their timing with reference to body rhythms. Rhythms in the pathophysiology of medical conditions and patient tolerance to medications constitute the basis for chronotherapeutics, the timing of treatment in relation to biological rhythm determinants as a means of optimizing beneficial effects and safety. The article discusses recent advances in medical chronobiology and chronotherapeutics and their relevance to clinical medicine in general and the management of asthma in particular. Indeed, since asthma is a disease that exhibits rather profound circadian rhythmicity, investigation of its pathophysiology and therapy necessitates a chronobiologic approach.     

尼美舒利的临床应用及其不良反应

尼美舒利具有强大的抗炎、镇痛和解热作用。临床主要用于急慢性疼痛、关节炎、月经痛、癌症疼痛和解热。其作用机理主要是通过选择性抑制COX-2而抑制前列腺素的合成。尼美舒利的不良反应与其他NSAIDs相似,但对胃肠道副作用较少。本文总结了尼美舒利的主要临床应用及不良反应。     

NMDA受体和长时程增强

近年来,N-甲基-D-门冬氨酸（NMDA）受体在突触可塑性形式——长时程增强（long-term potentiation,LTP）中的作用及该受体被激活后的细胞内级联反应备受人们的关注.人们利用拮抗剂技术和基因敲除的方法,对其进行了广泛的研究,并且就LTP的诱导和维持方面获得了一些进展.已获得的这些研究结果为LTP的突触前及突触后机制提供了有力的证据.     

匹伐他汀临床应用的最新进展

匹伐他汀(pitavastatin)是新一代人工合成的降血脂类药物。该药是新一代HMG-COA还原酶抑制剂,用于治疗原发型高脂血症和混合型血脂障碍,能够显著降低LDL、TC、TG、及升高HDL-C。药物动力学性质优良,具有肝细胞选择性,并且毒性低,安全性好,具有抗动脉粥样硬化、促进血管生成和抗炎作用。本文就匹伐他汀的临床研究进展进行综述。