Nondigestible oligosaccharides as dietary fiber

An overview is presented of the most important oligosaccharides that are classified as dietary fiber. Their occurrence and structures as well as their various physiological effects are described. The scientific evidence for health effects, associated with these physiological effects, along with the applications in the food industry, are also discussed.     

一氧化氮、一氧化碳与血红素的配位化学及其生理作用

NO和CO是新近发现的具有重要生理作用的生物活性小分子,其特定的生理效应主要是通过与生物体内血红素蛋白的配位作用产生的。本文比较了NO、CO、O2 与高铁血红素、亚铁血红素的配位化学性质,以及它们与亚铁血红素配位所产生的反位效应,简述了这些配位化学性质与生理作用的相关性。     

Comparison of subcellular responses for the evaluation and prediction of the chemotherapeutic response to cisplatin in lung adenocarcinoma using Raman spectroscopy

Confocal Raman Micro-spectroscopy (CRM) is employed to examine the chemical and physiological effects of anticancer agents, using cisplatin and A549 adenocarcinoma cells as a model compound and test system respectively. Spectral responses of the membrane and cytoplasm of the cell are analysed independently and the results are compared to previously reported spectroscopic studies of the nucleus. Moreover, Raman spectra from the proteins extracted from the control and exposed samples are acquired and analysed to confirm the origin of the molecular changes of the cell membrane and cytoplasm of the A549 cells. Multivariate data analysis techniques including Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR) along with PLS-Jackknifing are used to analyse the data measured from the cell membrane and cytoplasm of the A549 cells and results are correlated with parallel measurements from the cytotoxicity assay MTT. A PLSR model is used to differentiate between the chemical effect of the chemotherapeutic agent and the physiological response of the A549 cells and to identify regions of the spectrum that are associated with these processes respectively. The PLSR model is also employed to predict, on the basis of the Raman spectra, the effective dose as well as the level of physiological response, using spectra data from the cytoplasmic and cell membrane regions. The effectiveness of the models based on spectral datasets from the cell membrane and cytoplasm is compared to similar models constructed using spectral data from the nuclear region as well as one combining spectral data from all regions. In all cases, higher prediction accuracy is found for regression against the cisplatin dose, and for both regression against the dose and the physiological response, nuclear data yield higher precision.     

A General Route to Synthesis of 1-Substituted Taurines

Several 2-aminoalkanesulfonic acids have been found in many mammalian tissues till now and are involved in various and important physiological processes. Recently attention has been paid to their syntheses for studies of these physiological processes, the structural modification of natural peptides to overcome the limitations associated with their development as therapeutically useful agents, and information on the nature and mechanism of the peptide-receptor interactions.     

Plant calorimetry: A window to plant physiology and ecology

The use of calorespirometry in developing models for biological growth is discussed. The relationships between respiratory heat, CO₂, and O₂ rates and physiological parameters such as substrate carbon conversion efficiency, and substrate and biomass carbon oxidation states are presented and discussed. A biochemical model relating ratios of the respiratory rates to the physiological parameters and biochemical pathways in plants is presented. Examples of applications of these models and equations to plant physiology and ecology are given.     

一氧化碳有机荧光探针和光控释放剂研究进展

一氧化碳(CO)是人体内重要的气体信号分子, 在多种重要的生理病理代谢活动中起着关键性的调控作用, 被认为是具有广泛医学应用前景的药物活性分子. CO生理学效应与其浓度、空间分布密切相关. 因此, 生物体内特异检测CO以及可控性供给CO对于充分理解并有效利用其生理病理功能具有十分重要的意义. 荧光检测和光控释放因其无侵入性、时空可控等优势被广泛地运用于细胞、组织及活体内生物活性小分子的示踪和运输. 鉴于此, 本综述总结了近年来CO有机荧光探针和光控释放剂的研究进展, 着重阐述了其识别机理、释放机制和生物应用, 并展望了CO荧光探针和光控释放剂的发展趋势和应用前景.     

Challenges in quantum dot-neuron active interfacing

Semiconductor nanocrystal quantum dots (qdots) are now being explored in applications requiring active cellular interfaces, such as biosensing and therapeutics in which information is passed from the qdot to the biological system, or vice versa, to perform a function. These applications may require surface coating chemistry that is different from what is commonly employed for passive interface applications like labeling (i.e., thick polymer coatings such as poly(ethylene glycol) (PEG)), in which the only concern is nonspecific sticking to cells and biocompatibility. The thick insulating coatings that are generally needed for labeling are generally not suitable for active qdot-cell interface applications. There is currently little data regarding the interactions between viable cells and qdots under physiological conditions. Our initial investigations using mercaptoacetic acid-coated CdS and CdTe qdots as a simple model to interface with neuron cell surface receptors under physiological conditions uncovered two significant technological hurdles: nonspecific binding and endocytosis. Nonspecific binding can be extensive and in general there appears to be greater nonspecific binding for larger particle sizes, but this also depends sensitively on the particle surface characteristics and the type of neuron, possibly indicating a detailed relationship between particle-cell affinity and cell membrane chemistry. More importantly, qdot endocytosis occurs rapidly at physiological temperature for the different nerve cell types studied, within the first five minutes of exposure to both CdS and CdTe qdots, regardless of whether the molecular coatings specifically recognize cell surface receptors or not. As a consequence, new strategies for tagging cell surface recognition groups for long-term active interfacing with cells under physiological conditions are needed, which requires more sophisticated ligands than MAA but also the absence of thick insulating coatings.     

Quantitative analysis of methylguanidine and guanidine in physiologic fluids by high-performance liquid chromatography-fluorescence detection method.

A rapid and sensitive high-performance liquid chromatographic method has been developed for the quantitative analysis of methylguanidine and guanidine in physiological fluids. These quanidino compounds are separated on a 6 x 0.23 cm cation-exchange column with 0.5 M sodium hydroxide solution. The guanidino compounds are detected with a fluorometer, which monitors the fluorescent guanidine derivatives produced by the reaction of the eluted constituents with 9,10-phenanthrenequinone. Sensitivity to sub-nanomole levels of methylguanidine and guanidine is demonstrated. The method was successfully applied to physiological fluids such as serum and cerebrospinal fluid from uremic patients.     

A luminescent receptor with affinity for N-terminal histidine in peptides in aqueous solution

Crown ethers of suitable size are the perfect artificial host compounds for ammonium ion binding, but the rather low affinity in aqueous solution prevents their use at physiological conditions. We report here the synthesis and properties of a luminescent benzo crown ether with a pendant copper imidodiacetic acid complex, which coordinates with high affinity to histidine. The emission intensity of the benzo crown ether increases significantly in the presence of ammonium ions in methanol. At physiological conditions in buffered water at pH 7.5 these interactions are too weak to be detected. If an ammonium ion and an imidazole moiety are present in the analyte, such as in His-Lys-OMe or His-OMe, high binding affinity in aqueous solution is restored. The binding event is signaled by an increase in emission intensity, which can even be observed with the naked eye. This allows the selective detection of small peptides containing N-terminal histidine or histidine among all other amino acids at physiological conditions.     

Evaluation of peptide electropherograms by multivariate mathematical-statistical methods. I. Principal component analysis.

Depository effects in slowly metabolised proteins, typically glycation or the estimation of products arising from the reaction of unsaturated long-chain-fatty acid metabolites (possessing aldehydic groups) are very difficult to assess owing to their extremely low concentration in the protein matrix. In order to reveal such alterations we applied deep enzymatic fragmentation resulting in a set of small peptides, which, if modified, are likely to change their electrophoretic properties and can be visualised on the resulting profile. Peptide maps of collagen (a mixture of collagen types I and III digested by bacterial collagenase) were applied as the model protein structure for detecting the nonenzymatic posttranslational changes originating during various physiological conditions like high fructose diet and hypertriglyceridemic state. Capillary electrophoresis in acidic media (sodium phosphate buffer, pH 2.5) was used as the separation method capable of (partial) separation of over 60 peptide peaks. Two to 13 changes were revealed in the profiles obtained reflecting the physiological conditions of the animals tested. Combination of peptide profiling with subsequent t-test evaluation of individual peak areas and principal component analysis based on cumulative peak areas of individual sections of the electropherograms allowed to determine in which section (part) of the electropherogram the physiological state indicating changes occurred. Simultaneously it was possible to reveal the qualitative differences between the four physiological regimes investigated (i.e., which regime affects the collagen molecules most and which affects them least). The approach can be used as guidance for targeted preseparation of the very complex peptide mixture.     

Synthesis of Potential Cytotoxic α-Methylene γ-Lactams

α-Methylene γ-lactones are known to have physiological activity, especially as cytotoxic agents, and are widely found in nature (1). However they are often toxic which makes them inappropriate for cancer treatment.     

Ground-state properties of the retinal molecule: from quantum mechanical to classical mechanical computations of retinal proteins

Retinal proteins are excellent systems for understanding essential physiological processes such as signal transduction and ion pumping. Although the conjugated polyene system of the retinal chromophore is best described with quantum mechanics, simulations of the long-timescale dynamics of a retinal protein in its physiological, flexible, lipid-membrane environment can only be performed at the classical mechanical level. Torsional energy barriers are a critical ingredient of the classical force-field parameters. Here we review briefly current retinal force fields and discuss new quantum mechanical computations to assess how the retinal Schiff base model and the approach used to derive the force-field parameters may influence the torsional potentials.     

Advances in zebrafish high content and high throughput technologies

The zebrafish has emerged as an excellent transitional screening model system between cell-based assays, which are rapid and inexpensive but have limited physiological relevance, and higher vertebrate models, which have better physiological relevance, but are more time-consuming and expensive to deploy. As vertebrates, zebrafish maintain significant evolutionary proximity to humans and have been validated as robust models for drug research, studies of mechanism and behavioral genetics. Unlike higher vertebrate models, zebrafish are well-suited to high-throughput applications owing to their high fecundity, rapid extrauterine development and transparency during organogenesis enabling in vivo labeling and imaging. Recent advances have been made in automating high content and high-throughput zebrafish screens, with the goal of developing fully automated drug screening platforms. The application and continued development of these technologies holds potential clinical significance in drug discovery and elucidating disease mechanisms.     

Herbizide für die Landwirtschaft: Chemische Unkrautbekämpfung

This article describes the most important herbicides relevant in the market place at the moment as well as their molecular modes of action and plant physiological effects. Furthermore also new herbicidal modes of action and the importance of safeners are referred to.     

Protein Phosphorylation and Cellular Information Transfer: Signaling by MAP Kinase Cascades

Summary. Living cells, unicellular organisms as well as cells of multicellular organisms, are permanently exposed to a multitude of signals. Cells have to transform these external stimuli into physiological intelligible signals that are transduced from outside of the cell into the cell to induce a proper cellular response. Extracellular stimuli are perceived and internalised by various cellular receptors. Subsequently, signals are transduced by one of many protein kinase signaling cascades. Mitogen-activated protein kinases (MAPKs) belong to the evolutionary most conserved class of such molecular switches. MAPKs can change the activity of target proteins and thereby bring about physiological responses to external signals. This review discusses the basic principles of MAPK pathways in the context of cellular information processing: Cellular bioinformatics is an increasingly important interdisciplinary field with important implications for basic and applied sciences.Received February 24, 2003; accepted March 28, 2003 Published online August 18, 2003     

Analysis of Polysaccharides in Shii - Take fiom Guizhou

Polysaccharides, special those with physiological actions and nutrition, are widely used as an important resources for food, medicine industries, health etc. Herba Glossogynes Tenuifoliae (Shii-Take) is rich in polysaccharides with physiological actions and nutrition. Guizhou lies to the southwest of China, Natural resources abound in this province, in which there is high output and many species of Shii-Fake. So study in the Shii-Take is favor of reasonably utilizing the natural resources and getting high addvalue products. And what is more, It is necessary for energetically developing west economy.     

Investigation of the specificity of Raman spectroscopy in non-invasive blood glucose measurements

Although several in vivo blood glucose measurement studies have been performed by different research groups using near-infrared (NIR) absorption and Raman spectroscopic techniques, prospective prediction has proven to be a challenging problem. An important issue in this case is the demonstration of causality of glucose concentration to the spectral information, especially as the intrinsic glucose signal is smaller compared with that of the other analytes in the blood–tissue matrix. Furthermore, time-dependent physiological processes make the relation between glucose concentration and spectral data more complex. In this article, chance correlations in Raman spectroscopy-based calibration model for glucose measurements are investigated for both in vitro (physical tissue models) and in vivo (animal model and human subject) cases. Different spurious glucose concentration profiles are assigned to the Raman spectra acquired from physical tissue models, where the glucose concentration is intentionally held constant. Analogous concentration profiles, in addition to the true concentration profile, are also assigned to the datasets acquired from an animal model during a glucose clamping study as well as a human subject during an oral glucose tolerance test. We demonstrate that the spurious concentration profile-based calibration models are unable to provide prospective predictions, in contrast to those based on actual concentration profiles, especially for the physical tissue models. We also show that chance correlations incorporated by the calibration models are significantly less in Raman as compared to NIR absorption spectroscopy, even for the in vivo studies. Finally, our results suggest that the incorporation of chance correlations for in vivo cases can be largely attributed to the uncontrolled physiological sources of variations. Such uncontrolled physiological variations could either be intrinsic to the subject or stem from changes in the measurement conditions.     

Exosome based miRNA delivery strategy for disease treatment

miRNA, which is a common non-coding RNA, can target various m RNAs to regulate their physiological activities. Therefore, mi RNAs play an important role in various physiological and pathological processes,and so they have been proposed as a powerful tool to treat different diseases efficiently. However, the characteristic of mi RNA degradation in vivo limits its further clinical application. Exosomes have the advantage of crossing the biological barrier and achieving long-distance communication ...     

Direct detection of low-concentration NO in physiological solutions by a new GaAs-based sensor

Nitric oxide (NO) acts as a signal molecule in the nervous system, as a defense against infections, as a regulator of blood pressure, and as a gate keeper of blood flow to different organs. In vivo, it is thought to have a lifetime of a few seconds. Therefore, its direct detection at low concentrations is difficult. We report on a new type of hybrid, organic-semiconductor, electronic sensor that makes detection of nitric oxide in physiological solution possible. The mode of action of the device is described to explain how its electrical resistivity changes as a result of NO binding to a layer of native hemin molecules. These molecules are self-assembled on a GaAs surface to which they are attached through a carboxylate binding group. The new sensor provides a fast and simple method for directly detecting NO at concentrations down to 1 microM in physiological aqueous (pH=7.4) solution at room temperature.