Diffusion coefficient and molecular weight of type 5 adenovirus by photon-correlation spectroscopy

The technique of photon-correlation spectroscopy (intensity fluctuation spectroscopy) is applied to light scattered from type 5 adenovirus undergoing Brownian motion in solution and the translation diffusion coefficient (D₂₀,W) measured to be 0.367 ± 0.003 Fick units. Using Svedberg's equation with previously determined parameters, a molecular weight of 165 · 10⁶ ± 5 · 10⁶ is obtained.     

Children and Youth in Aboriginal Australia: An Overview of the Literature

The following overview of the existing literature relating to Aboriginal childhood and adolescence across Australia is intended to support the development of this potentially strong interdisciplinary research field. It presents a select number of works in historical context, concluding with critical comments and supplemented by additional references presented according to type of study. No claim is made to have covered the literature exhaustively.     

The Mechanism of Eukaryotic Translation Initiation: New Insights and Challenges

Translation initiation in eukaryotes is a highly regulated and complex stage of gene expression. It requires the action of at least 12 initiation factors, many of which are known to be the targets of regulatory pathways. Here we review our current understanding of the molecular mechanics of eukaryotic translation initiation, focusing on recent breakthroughs from in vitro and in vivo studies. We also identify important unanswered questions that will require new ideas and techniques to solve.This work aims to present the current state of our knowledge of the molecular mechanics of translation initiation in eukaryotes. We focus on advances that have taken place over the last few years and, because of space limitations, assume readers will be able to find references to the foundational literature for the field (published before 2000) in the more recent works that are cited here. As always, we apologize for not having the space to cite many important works. Please view this as merely an introduction to the field rather than a complete summary.     

Complete Bibliography of Eugenie C. Scott

Bibliographic references for all works authored by Eugenie C. Scott are provided, including her contributions to the publications of the National Center for Science Education and to other sources. The publication history of the various NCSE publications is explained.     

The effect of guanidinium chloride on the behaviour of human cervical-mucus glycoproteins. Evidence for unfolding regions of ordered structure in 6M-guanidinium chloride.

The macromolecular properties of cervical-mucus glycoproteins (mucins) were studied as a function of the concentration of guanidinium chloride with conventional light-scattering, photon-correlation spectroscopy and sedimentation-velocity centrifugation. No evidence for an association of the mucins in 0.2M-NaCl as compared with 6M-guanidinium chloride was found at mucin concentrations below approx. 0.5 mg/ml. However, an increase in the frictional coefficient and in the radius of gyration occurred with increasing concentrations of guanidinium chloride, in particular between 4 M and 6 M, suggesting an expansion of the individual macromolecule. The change in the particle-scattering function is consistent with a transition from a 'stiff' random coil in 0.2 M-NaCl into a more flexible one in 6 M-guanidinium chloride. We suggest that the mucins contain regions of 'ordered' structure which can undergo a reversible 'unfolding' analogous to the behaviour of a conventional globular protein exposed to a denaturing solvent. Such regions might carry sites for specific interactions between mucins and/or be decisive for their conformation and macromolecular properties in physiological solvents.     

Why the world needs protists!

In this brief review, literature references are given to researches--involving diverse species of protists--that support the author's firm conviction that the biological world of today absolutely requires the presence of numerous of these generally small and unicelled organisms if it is to survive. Examples supplied come from areas within the field of protistology sensu lato as widely separated as basic phycological research on photosynthesis and protozoological/medical/biomedical investigations on malaria and other pathogens of human beings. Emphasis is primarily on the most relevant works of the past 10-15 years, although historically highly significant papers of older vintage require at least indirect--and occasionally direct--citation.     

Determination of absolute configuration--an overview related to this special issue

Rapid progress in asymmetric synthesis stimulated a further development of methods and techniques for the determination of absolute configuration of chiral molecules. In recent years the direct methods, i.e. X-ray diffraction analysis, circular dichroism (vibrational and electronic), Raman optical activity, optical rotation measurements, as well as indirect methods for relative configuration assignment with the use of NMR spectroscopy or enzymatic transformations, are receiving increasing attention not only by specialists in the field but also by synthetic and structural chemists alike. This paper provides a short overview of the methods currently used, as well as references to contributions collected in this Thematic Issue of Chirality.     

Potassium-induced motion increase in a central nervous ganglion.

1. By means of light-beating spectroscopy, a four-fold increase in the modulation of laser light scattered at right angles by a locust (Schistocerca gregaria, Forsk?l) ganglion is detected when potassium ions replace sodium ions in the Ringer solution. 2. This is interpreted as an increased level of motion of the scattering particles (size 0.3-3.0 mum, if viscosity is taken to be 0.01 poises). 3. The amplitude of the potassium-response is similar at all frequencies in the range 6.3-150 Hz and is reversible on return to normal (Na+) Ringer. 4. Desheathing the ganglion reduces the half-time of the potassium-response by 3-4 times. 5. By means of photon-correlation spectroscopy it was estimated that less than 10% of the tissue contributes to the motion detected. 6. Cyanide (1-2 mM) typically enhances the potassium-response and renders it irreversible, suggesting that the response is thermally rather than metabolically-driven. In addition, the dependence of both the correlation function and the power spectrum on the scattering angle is in the direction predicted for a diffusive process. 7. Cobaltous ions (2-10 mM), which block calcium entry into nerve cells, depress the potassium-response. 8. It is proposed that potassium-depolarization and the resultant calcium entry into the cells causes a partial liquefaction of the cytoplasms which is detected as an increase in the level of Brownian motion. This mechanism could be used in vesicular release or in growth.     

拉曼光谱分析技术在细胞生物学研究中的应用进展

细胞是生物体结构和功能的基本单位,自被发现以来新的研究方法不断涌现。单细胞拉曼光谱能提供细胞内核酸、蛋白质、脂质含量等大量信息,可在不损伤细胞的条件下实时动态地监测细胞分子结构变化,亦可获得细胞的“分子指纹”,具有敏感性高、实时检测、活样品不需固定或染色、不损伤细胞等众多特点。近年来国内外研究者将拉曼光谱应用于细胞药物处理、细胞水平疾病诊断、单细胞生命活动监测、亚细胞结构等研究,取得了不同程度的进展。随着研究的深入,拉曼光谱分析技术必将在干细胞,癌症研究、细胞分选、药物筛选等领域大有作为。     

Hydrodynamic properties of human cervical-mucus glycoproteins in 6M-guanidinium chloride.

Cervical mucins and fragments thereof were studied by sedimentation-velocity, rotatory viscometry and laser light-scattering performed as photon-correlation spectroscopy as well as low-angle total-intensity measurements. The Mr of the whole mucins is 10 X 10(6)-15 X 10(6), whereas fragments obtained after reduction of disulphide bonds ('subunits') have Mr 2.1 X 10(6)-2.9 X 10(6), depending on the method used. Subsequent trypsin digestion of subunits afforded glycopeptides with Mr approx. 0.4 X 10(6). The high frictional ratio for the whole mucins is interpreted as a large degree of expansion. The Stokes radius calculated from the diffusion coefficient is approx. 110nm for the whole mucins, which is in agreement with that estimated from the radius of gyration (130nm) by using the concept of the equivalent hydrodynamic sphere. The ratio of the concentration-dependence parameter for the reciprocal sedimentation coefficient (Ks) to the intrinsic viscosity ( [eta] ) for the whole mucins is 1.42, suggesting that the individual macromolecule occupies a spheroidal domain in solution. The relationship between [eta] and Mr for whole mucins, subunits and T-domains suggests that they are linear flexible macromolecules behaving as somewhat 'stiff' random coils. This conclusion is supported by the relationships between the sedimentation coefficients, the diffusion coefficients and the Mr. The hydrodynamic behaviour of the mucins is thus close to that expected for coiling macromolecules entrapping a lot of solvent, which is consistent with the postulated polymeric structure.     

多光谱成像技术在生物医学中的应用进展

多光谱成像(multispectral imaging,MSI)技术在生物医学可视化方面是一种新技术,它结合了两个已建立的光学模块:成像学和光谱学。它的原理是基于液晶可调谐滤光片,从可见光到近红外波长(400-970nm)区域获取多光谱图像。自从MSI系统加上显微镜商品化以来,MSI已经成为一种快速发展的领域,可应用于细胞生物学、临床前药物开发和临床病理学等。国外已有大量关于MSI在生物医学中应用的研究报道,但国内报道少见。本文主要对多光谱成像的基本原理,近三年内该技术在生物医学领域的应用进展作一简要综述。     

An analysis of the scientific publications of the A. A. Bogomolets Institute of Physiology of the Academy of Sciences of Ukraine]

Scientific publications from three sectors of the Institute have analyzed for the period since 1979 till 1988 inclusive. The analysis is based on data of annual reference books Science Citation Index (SCI) and lists of publications of each researcher of the Institute. It is shown that with almost equal numerical strength of researchers and similar number of publications the sector of molecular physiology contributed 43.6% to cited works 48.2% of these works are included into database of SCI. Such indices for the sectors of neurophysiology and physiology of visceral systems accounted for 33%, 33.4% and 23.4, 18.4% respectively. It is of interest that 47.5% of references to the cited works of the molecular physiology sector were made by foreign scientists and self-citation constituted 17.4%, while for the other sectors such indices had a reverse relationship. The problem on objectification of estimation of research is under discussion.     

Current views on pectin substances

This review concerns pectin substances, the most complex class of plant polysaccharides. For the most part, the data reported after 1998 are presented; the references to earlier works are made only in the historical aspect. New data on the structure of pectin substances, their physiological activity, their role in plants, and their valuable physical properties are surveyed.     

Huron Smith's ethnobotany of the Hocąk (Winnebago)

The Hocak, commonly known as the Winnebago, are one of the original tribes in the present state of Wisconsin. The field notes of Huron Smith, compiled in the late 1920s and early 1930s, document the extensive use of plant materials by Hocak people. Smith's notes contain references to 199 vascular plant species in 74 families, with recorded uses for 153 of these species. Medicinal plants (with 117 species) comprise the largest category, followed by food (37 species), and fiber and material uses (22 species). Smith's work is unique for its time because he thoroughly explored the tribal uses of the plants in addition to collecting voucher specimens and photographic plates, and because it remains the most extensive Hocąk ethnobotanical study. Added to Smith's other works of tribes in Wisconsin (Menominee, Meskwaki, Ojibwe, and Potawatomi), the Hocak ethnobotany broadens the cultural base of his regional compilation of Native North American plant uses. In addition, this is an important body of information for the Hocąk people and those interested in their use of plants.     

A BIBLIOGRAPHY RELATING TO THE ECOLOGY AND ENERGETICS OF EAST AFRICAN LARGE MAMMALS

Many investigations have made contributions to an understanding of energy flow through large mammals in East African ecosystems. This paper lists references to such works and compiles them according to their application to various segments as they appear in an energy-flow model. The first part indicates papers on pasture utilization, value of foodstuffs, animal numbers and distribution, population dynamics and secondary production. The second part assembles references dealing with individual animal species, stratifying them according to the subjects of ecology, food habits and nutrient utilization, population dynamics and growth.     

Identification and properties of complexes formed by myeloperoxidase with lipoproteins and ceruloplasmin

The first evidence of multi-component complexes formed by myeloperoxidase (MPO), ceruloplasmin (CP), and very low/low density lipoproteins (VLDL/LDL) obtained by electrophoresis, gel filtration, and photon-correlation spectroscopy (PCS) is presented in this paper. Complexes were observed when isolated MPO, CP, and VLDL/LDL were mixed and/or when MPO was added to the blood plasma. Complex LDL–MPO–CP was detected in 44 of 100 plasma samples taken from patients with atherosclerosis, and 33 of 44 samples also contained the VLDL–MPO–CP complex. MPO concentration in these patients’ plasma exceeded 800 ng/ml. Interaction of MPO with high density lipoproteins (HDL) was not revealed, as well as binding of CP to lipoproteins in the absence of MPO. Adding antibodies against apoB-100 to VLDL–MPO–CP and LDL–MPO–CP complexes results in release of lipoproteins. Using PCS the diameters of complexes under study were evaluated. By comparing concentrations of the components in complexes formed by MPO, CP, and lipoproteins their stoichiometry was assessed as 2VLDL:1MPO:2CP and 1LDL:1MPO:2CP. Lipoproteins affected the inhibition of MPO peroxidase activity by CP. The affinity of lipoproteins to MPO–CP complex was assessed using apparent dissociation constants determined as ～0.3 nM for VLDL and ～0.14 nM for LDL.     

生物组织光学特性检测中的探头设计

在组织光谱检测中,探头的设计至关重要。本文首先对近红外测量探头进行了分类,并探讨了它们各自的特点,然后详细介绍并比较了几种典型的探头设计,最后总结了探头设计的优化方法及其发展趋势。     

氨基酸分析检测方法的研究进展

对氨基酸分析常用的检测方法:分光光度法、气相色谱法、液相色谱法、毛细管电泳法及其它方法(近红外光谱法、化学发光法、荧光光谱法)进行综述,并介绍了这些方法在氨基酸检测中的应用,为建立快速、高效的氨基酸分析方法提供参考.     

When Good Lawyers Write Bad History: Unreliable Evidence and the South China Sea Territorial Dispute

The recent award by an arbitral tribunal in a case brought by the Philippines against China gives lawyers reason to reexamine the historical evidence put forward by claimants in the South China Sea disputes. While the Tribunal was barred from considering territorial or boundary questions, it did cast doubt on the historical narrative rule that China has asserted in support of its claims. Fresh evidence from other sources also suggests that discussions of these matters need to move beyond arguments put forward in a small number of papers published more than thirty years ago. A close examination of the references used in those papers shows that they relied upon highly partisan Chinese sources. Recent historical research has produced new facts about the development of the competing territorial claims in the South China Sea, but international legal discourse has yet to take these findings into account. This article examines some of the key works in the field and calls for them to be reassessed and for future discussion of the disputes to be based upon verifiable and contextualized evidence rather than on nationalist assertions.