Microbial and bioconversion production of D-xylitol and its detection and application

D-Xylitol is found in low content as a natural constituent of many fruits and vegetables. It is a five-carbon sugar polyol and has been used as a food additive and sweetening agent to replace sucrose, especially for non-insulin dependent diabetics. It has multiple beneficial health effects, such as the prevention of dental caries, and acute otitis media. In industry, it has been produced by chemical reduction of D-xylose mainly from photosynthetic biomass hydrolysates. As an alternative method of chemical reduction, biosynthesis of D-xylitol has been focused on the metabolically engineered Saccharomyces cerevisiae and Candida strains. In order to detect D-xylitol in the production processes, several detection methods have been established, such as gas chromatography (GC)-based methods, high performance liquid chromatography (HPLC)-based methods, LC-MS methods, and capillary electrophoresis methods (CE). The advantages and disadvantages of these methods are compared in this review.     

Science and society: death, unconsciousness and the brain

The concept of death has evolved as technology has progressed. This has forced medicine and society to redefine its ancient cardiorespiratory centred diagnosis to a neurocentric diagnosis of death. The apparent consensus about the definition of death has not yet appeased all controversy. Ethical, moral and religious concerns continue to surface and include a prevailing malaise about possible expansions of the definition of death to encompass the vegetative state or about the feared bias of formulating criteria so as to facilitate organ transplantation.     

Cytokine and anti-cytokine therapy for the treatment of asthma and allergic disease

Until recently, the only controller treatment for chronic asthma has been corticosteroids. However, identification of specific effector molecules in asthma has led to targeting of specific pathways by using cytokines and cytokine inhibitors. Administration of a monoclonal blocking antibody against IgE has been shown to be highly efficacious in severe allergic asthma, but blockade of eosinophils using anti-IL-5 monoclonal antibodies has no clinical benefit. In more severe asthma, blockade of TNF-alpha using the decoy etanercept has revealed efficacy in a small open study suggesting that Th-1 in addition to Th-2 pathways are important as the disease adopts a more severe phenotype. It is likely that asthma is not a single disease but a group of disorders which differ in the relative contribution of specific pathophysiological pathways.     

Brain and Mind

In the last few years great progress has been made in many fields of knowledge. Technology has moved forward with rapid strides, and with the appearance of self-regulating systems it has moved to a new stage. Significant progress has been achieved in physics and biology; new branches of medicine have been formulated and are being developed; and substantial changes have also been noted in a sphere of particular relevance and importance for each of us, in psychology, the science of man's mental life and the laws of his behavior.     

Bird conservation and biodiversity research in Mexico: status and priorities

Mexico has a megadiverse avifauna that includes many endemic elements, as well as rich sets of species ranging farther north or farther south in the Americas. This avifauna, nonetheless, has suffered considerable losses as a consequence of long‐term, intensive human activity across the landscape. We review what is known about the Mexican avifauna, specifically its diversity and endemism, and how that knowledge has and has not turned into effective conservation measures to assure the long‐term integrity of the avifauna.     

Ultrasound and hydroultrasound diagnosis of colonic and rectal tumors

A method of US hydrocolonoscopy with the use of multicomponent contrast medium has been applied to examine 76 patients with tumors of the straight intestine and segmented one. Cancer has been diagnosed in 56 patients, benign tumors in 19 patients, lymphosarcoma of the blind gut has been revealed in one case. It is stated that a complex US examination of the straight and segmented intestines has a number of additional diagnostic potential in a visualization of the wall thickness, structure, tumor size and in a determination of the lesion length as compared with other radiation methods of observation. The use of survey US examination of the abdomen, USE with liquid echocontrast diagnostic medium and transrectal observation enable to solve in most cases severe problems in diagnosis and differential diagnosis of cancer of the straight intestine and segmented one.     

Coding and traceability for cells,tissues and organs for transplantation

Modern transplantation of cells, tissues and organs has been practiced within the last century achieving both life saving and enhancing results. Associated risks have been recognized including infectious disease transmission, malignancy, immune mediated disease and graft failure. This has resulted in establishment of government regulation, professional standard setting and establishment of vigilance and surveillance systems for early detection and prevention and to improve patient safety. The increased transportation of grafts across national boundaries has made traceability difficult and sometimes impossible. Experience during the first Gulf War with miss-identification of blood units coming from multiple countries without standardized coding and labeling has led international organizations to develop standardized nomenclature and coding for blood. Following this example, cell therapy and tissue transplant practitioners have also moved to standardization of coding systems. Establishment of an international coding system has progressed rapidly and implementation for blood has demonstrated multiple advantages. WHO has held two global consultations on human cells and tissues for transplantation, which recognized the global circulation of cells and tissues and growing commercialization and the need for means of coding to identify tissues and cells used in transplantation, are essential for full traceability. There is currently a wide diversity in the identification and coding of tissue and cell products. For tissues, with a few exceptions, product terminology has not been standardized even at the national level. Progress has been made in blood and cell therapies with a slow and steady trend towards implementation of the international code ISBT 128. Across all fields, there are now 3,700 licensed facilities in 66 countries. Efforts are necessary to encourage the introduction of a standardized international coding system for donation identification numbers, such as ISBT 128, for all donated biologic products.     

FOXP2 and the neuroanatomy of speech and language

That speech and language are innate capacities of the human brain has long been widely accepted, but only recently has an entry point into the genetic basis of these remarkable faculties been found. The discovery of a mutation in FOXP2 in a family with a speech and language disorder has enabled neuroscientists to trace the neural expression of this gene during embryological development, track the effects of this gene mutation on brain structure and function, and so begin to decipher that part of our neural inheritance that culminates in articulate speech.     

Cytochrome f from spinach and cyanobacteria. Purification and characterization

Cytochrome f has been purified from spinach chloroplasts and from the photosynthetic membranes of the cyanobacterium Spirulina maxima. The spinach protein has an isoelectric point of 5.2 and gives a single band on isoelectric focusing gels. The S. maxima cytochrome shows a major band with a pI of 4.01 and a minor band with a pI of 3.97. S. maxima cytochrome f has a molecular weight approximately 38,000 and is monomeric, while the spinach protein is slightly smaller, approximately 36,000 daltons, and aggregates to form an octamer. S. maxima cytochrome f has an E'0 of +339 mV which is close to that of cytochromes f from higher plants. The NH2-terminal amino acid sequences of the cytochromes show striking similarities. Spinach cytochrome f shows a clear preference for oxidation by spinach plastocyanin and S. maxima cytochrome f is more readily oxidized by its in vivo reaction partner, cytochrome c553.     

The purification and characterization of glutaryl-coenzyme A dehydrogenase from porcine and human liver

Glutaryl-CoA dehydrogenase, a multifunctional enzyme responsible for dehydrogenation and decarboxylation of glutaryl-CoA to crotonyl-CoA, has been purified 1,680-fold from porcine liver mitochondria. The purified porcine enzyme has a subunit molecular weight of 47,800 and a native molecular weight of 190,500. Porcine glutaryl-CoA dehydrogenase catalyzed the conversion of [1,5-14C]glutaryl-CoA to [14C] crotonyl-CoA and 14CO2 in a 1:1:1 ratio. The porcine enzyme has Km values for electron transfer flavoprotein and glutaryl-CoA of 1.1 and 3.3 microM, respectively, and turnover numbers of 860 mol of electron transfer flavoprotein/min/mol of glutaryl-CoA dehydrogenase and 327 mol of glutaryl-CoA/min/mol of glutaryl-CoA dehydrogenase. Human glutaryl-CoA dehydrogenase has been purified 1,278-fold from human liver mitochondria. The purified human enzyme has a subunit molecular weight of 58,800 and a native molecular weight of 256,000. Human glutaryl-CoA dehydrogenase showed a reaction of only partial identity when compared to porcine glutaryl-CoA dehydrogenase by Ouchterlony double immunodiffusion analysis using antiserum raised against and monospecific for porcine glutaryl-CoA dehydrogenase.     

普鲁士蓝纳米粒子在生物医学诊断和治疗中的应用及进展

随着生物医学诊断和治疗的持续深入研究,出现了多种医学诊断和治疗新方法,为人类的健康提供了更大的保证,其中纳米生物技术在生物医学诊断和治疗中的应用日益增多,基于纳米技术,开发传统材料的生物医学新应用成为了人们的研究热点。普鲁士蓝是一种历史悠久的蓝色染料,其制备过程简单、绿色、成本低,化学结构稳定,具有优良的物理、化学、光学以及磁性等性能,已经在许多领域得到了广泛的应用。近年来,普鲁士蓝开始在生物医学诊断和治疗领域中崭露头角,它已经成功的被开发为新型的核磁共振造影剂和光声成像造影剂,并且在药物输送系统和光热治疗等领域也开始占有一席之地,开发基于纳米技术的普鲁士蓝的生物医学应用已经成为极具吸引力的研究方向。本文对普鲁士蓝在生物医学诊断和治疗中的应用及进展进行综述。     

人类基因组及后基因组研究进展及其应用与开发研究现状

人类对自身基因组的研究,随着人类基因组工作草图的绘制完成和对基因功能研究的深入已加快进入了实质性、关键性的开发利用阶段。本文概述了人类基因组及后基因组的研究进展及依此开展基因治疗及基因（组）药物研制等应用开发研究的现状。     

MicroRNA，lncRNA与神经退行性疾病

综述了microRNA和lncRNA在一些神经退行性疾病病理生理中的作用机制．随着社会生产的发展,人类文明的进步,人口日益老年化,神经退行性疾病正在全球范围内流行,严重地危害着人类的健康．尽管长期的研究使人们对神经退行性疾病有了比较全面和深入的了解,但是其背后隐藏的发病机制仍然是个谜．人类基因组约98%的转录产物为非编码RNA(ncRNA),在生命活动中有着许多鲜为人知的广泛而多样性的生物功能．小分子RNA(microRNA)是研究得相对比较深入的一类小ncRNA,最近2～3年,长非编码RNA(lncRNA)受到人们的重视,已积累了一些相关研究成果．     

沙鼠脑缺血模型特点及应用的研究进展

脑缺血因其高的发病率而成为近年来研究的热点。用于研究脑缺血的动物模型较多,其中沙鼠因大脑基底动脉环先天性发育不完全而成为脑缺血研究的较理想模型。沙鼠脑缺血模型在研究单侧脑缺血和全脑缺血方面都具有独特的优势,在研究脑缺血后脑区的病理变化、再灌注损伤机制及开发脑保护药方面都得到十分广泛的应用。本文针对不同脑缺血模型尤其是沙鼠模型的制作方法、优缺点及应用领域,将近年来国内外相关研究文献进行较为系统的梳理和综述。     

Capillary electrophoresis and microdialysis: current technology and applications

Microdialysis sampling has become an important method for the continuous monitoring from an in vivo environment. This technique has been used to monitor many endogenous molecules, such as neurotransmitters, as well as exogenous species such as drug substances. Microdialysis samples have traditionally been analyzed by liquid chromatographic (LC) methods to gain resolution and quantification of the molecules of interest. However, LC separations have a relatively large injection volume requirement which, as a consequence, increases microdialysis sampling times. Capillary electrophoresis (CE), with its very small sample volume requirements and high resolving power, has therefore gained popularity as an alternative to LC. Reviewed here are many of the technologies currently available for CE and examples of how this technique has been effectively applied to the analysis of microdialysis samples.     

Prejudice and tolerance in a period of increasing ethnic diversity and growing unemployment: Denmark since 1970

Abstract

Since the end of the 1960s Denmark, once an ethnically homogeneous country, has become more heterogeneous as a result of immigration by foreign workers and refugees. The question is how has this development influenced the attitudes in Denmark towards immigrants? The saliency of the immigrant issue has certainly grown, but contrary to expectations, the level of ethnocentrism has changed very little. If anything, the Danish population has become less prejudiced and more tolerant during the last thirty years. This conclusion, based on a number of national surveys, is even more conspicuous as the level of unemployment has increased in the same period.     

Synthesis and Properties of Thiodiglycolaldehyde

Thiodiglycolaldehyde (1) has been synthesised by dehydration of its hemialdal form, cis-2,6-dihydroxy-I,4-oxathiane (2a). The hydration and polymerisation of 1 have been studied. The composition and conformational population has been established for solutions of 2a in various solvents. In aqueous solution, 1,2a and its trans isomer 2b, and the acyclic dihydrate and monohydrate were detected. The preferred conformer of 2a has diequatorial OH groups     

Cilia and ciliopathies: From Chlamydomonas and beyond

The biological function of motile cilia/flagella has long been recognized. The non-motile primary cilium, once regarded as a vestigial organelle, however, has been found recently to play unexpected roles in mammalian physiology and development. Defects in cilia have profound impact on human health. Diseases related to cilia, collectively called ciliopathies include male infertility, primary cilia dyskinesia, renal cyst formation, blindness, polydactyly, obesity, hypertension, and even mental retardation. Our current understanding of cilia and ciliopathies has been fueled by basic research employing various model organisms including Chlamydomonas, a unicellular green alga. This review article provides a general introduction to the cell biology of cilia and an overview of various cilia-related diseases.     

Mechanisms of thymus organogenesis and morphogenesis

The thymus is the primary organ responsible for generating functional T cells in vertebrates. Although T cell differentiation within the thymus has been an area of intense investigation, the study of thymus organogenesis has made slower progress. The past decade, however, has seen a renewed interest in thymus organogenesis, with the aim of understanding how the thymus develops to form a microenvironment that supports T cell maturation and regeneration. This has prompted modern revisits to classical experiments and has driven additional genetic approaches in mice. These studies are making significant progress in identifying the molecular and cellular mechanisms that control specification, early organogenesis and morphogenesis of the thymus.     

Dissection of ammonium uptake systems in Corynebacterium glutamicum: mechanism of action and energetics of AmtA and AmtB

Corynebacterium glutamicum has two different Amt-type proteins. While AmtB has a low substrate affinity and is not saturable up to 3 mM methylammonium, AmtA has a high substrate affinity and mediates saturable, membrane potential-dependent transport, resulting in a high steady-state accumulation of methylammonium, even in the absence of metabolic trapping.