Complex Biological Materials Research Articles

Compilation of EINECS: Descriptions and definitions used for UVCB substances: Complex reaction products, plant products, (post‐reacted) naturally occurring substances, micro‐organisms, petroleum products, soaps and detergents, and metallic compounds

The European INventory of Existing commercial Chemical Substances (EINECS) lists all substances which were on the European Community Market between 1 January 1971 and 18 September 1981. Substances on EINECS are known as ‘existing’ substances. The EINECS inventory was drawn up by the European Commission to meet the requirements of article 13 of Directive 79/831/EEC [Council Directive 79/831/EEC of 18 September 1979 amending for the sixth time Directive (EEC) 67/548 on the approximation of the laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances. Official Journal of the European Communities, 1979, L259. Office for Official Publications of the European Communities, L‐2985 Luxembourg], EINECS was published in the Official Journal of the European Communities in 1990 [European Inventory of Existing Commercial Chemical Substances, Annex to the Official Journal C146A, 15 June 1990, pp. 1–1802. Office for Official Publications of the European Communities, L‐2985 Luxembourg]. This article describes how substances of Unknown or Variable composition, Complex reaction products or Biological materials (UVCB substances), petroleum products and plant products were registered in EINECS. It is the third in a series of such papers.

Modelling the Mechanical Properties of Xylem Tissue from Tobacco Plants (Nicotiana tabacum‘Samsun’) by Considering the Importance of Molecular and Micromechanisms

Tobacco plants (Nicotiana tabacum‘Samsun’) have xylem cell walls which are more sensitive to changes in the properties of the matrix than was predicted using current cell wall mechanical models. A model is proposed which can account for the importance of the cell wall matrix in determining the modulus of the material. This model is based on a helical spring system, with micromechanisms operating at the molecular scale. Xylem tissue fibre cells can behave as helical springs when the crosslink density of lignin is low, or they can behave like a composite sheet with fibres at an angle to the applied load when the crosslink density is high. This highlights the importance of molecular modelling when the properties of complex biological materials are being investigated.

Position-Resolved Small-Angle X-ray Scattering of Complex Biological Materials

Many biological materials, like bone or wood, are hierarchically organized and optimized at all levels for their specific mechanical function. At the lowest level, these materials are fiber composites, where the fiber direction as well as the size of the individual components varies considerably with position inside a given specimen. For bone or wood, some of these parameters can be readily obtained by small-angle X-ray scattering (SAXS) in a position-resolved way. A scanning-SAXS system based on a pinhole camera with rotating anode and area detector is presented, and first applications to the study of bone and wood are reported.

Zinc (Zn2+) binds to and stimulates the activity of group i but not group II phospholipase A2

Phospholipase A2 plays an important part in the generation of inflammatory lipid mediators and so it is of major interest to understand functional distinctions between structurally similar forms of phospholipase A2. In the present study, the influence of zinc (Zn2+) on the activity of group I and group II phospholipase A2 was examined in vitro. It appeared that Zn2+ (0.04-1 x 10(-3)M) increased group I phospholipase A2 activity from porcine pancreas and rat lung whereas the activity of group II phospholipase A2 from Crotalus atrox and Vipera russelli was unaffected. The presence of Cd2+ of Hg2+ (0.8-5 x 10(-3)M) also increased group I pancreatic phospholipase A2 activity while no augmentation was found with Cr2+, Fe2+ or Mg2+. The selective stimulation of group I phospholipase A2 by Zn2+ corresponded to a binding of these phospholipases A2 to a zinc-affinity column, while group II phospholipase A2 was not bound. Furthermore, the PLA2 activity in bronchoalveolar lavage fluid from rat was stimulated by Zn2+. These results indicate that Zn2+ binds to and increases the activity of group I, but not group II phospholipase A2. This difference in Zn(2+)-binding may be used to discriminate between group I and group II phospholipase A2 and to separate the enzymes from each other in complex biological materials. The possibility that activation of group I phospholipase A2 in the lung is important in zinc-induced metal fume fever is implied.

5] Microcolumn liquid chromatography in biochemical analysis

Biochemical methodologies based on various forms of liquid chromatography (LC) have been extremely important to progress in both structural investigations and physicochemical measurements performed on biological macromolecules. The high-performance LC (HPLC) instruments, featuring analytical-scale (4.6-mm i.d.), and preparative columns have now become the standard equipment in biochemical laboratories. While such instrumentation performs admirably in the day-to-day tasks of a biochemist (ranging from isolation work to routine sequencing methods to various other determinations), there is an increasing need to work at the microscale and nanoscale. Miniaturization of chromatographic separations and the associated small-scale manipulations is certainly one way of dealing with the problem of analyzing minute quantities of important biomolecules isolated from complex biological materials. Increasing sophistication of chromatographic detectors, in terms of sensitivity and structural information, provides further incentive for the development of microcolumn separation methods. This chapter discusses the microcolumn LC and its related techniques to provide a perspective on its value in biochemical research. Whereas much developmental work in micro-LC employed separation of small molecules, the primary emphasis of the discussion is on biological macromolecules and their degradation products. After a brief discussion of the microcolumn types and their technology, the instrumental aspects pertinent to the field of biomolecular analysis are described in the chapter. Selected applications further demonstrate certain unique capabilities of microcolumn separation systems.

Imaging Complex Fluids Under Confinement and Flow: Development of Bragg-Fresnel Optics for X-ray Microdiffraction

ABSTRACTWe present results of simultaneous efforts to develop: 1.) Bragg-Fresnel Optics(BFO) to be used in X-ray microdiffraction methods, in particular as applied to structural studies of complex fluids and biomaterials under confinement and flow conditions; and 2.) Methodologies for confining complex fluids and biomaterials for in-situ structural studies. Using microelectronics process technology, we have fabricated linear and circular Bragg-Fresnel Lenses (BFL) in Si and III-V compound semiconductor substrates such as InP, GaAs and GaAs heterostructures with outermost zone width to 0.25 μm. X-ray characterization of linear BFLs were performed on a wiggler beamline at Stanford Synchrotron Radiation Laboratory (SSRL) at x-ray energies of 8 keV and 16 keV. A ∼5 μm focal spot size was obtained with a 50 μm incident beam, which was determined by the partial coherence of the source. On the confinement techniques, we have developed the X-ray Surface Force Apparatus (XSFA) which allows in-situ x-ray diffraction measurements to be made on fluid thin films confined between two atomically smooth surfaces. A new approach is being pursued to study the effects of confinement and flow on complex fluids and biological materials using microchannels fabricated on glass substrates.

QENS'93 meets in Spain

Abstract The Quasielastic Neutron Scattering workshop, held at Miramar Palace, San Sebastian, Basque Country (Spain) on September 26–28, 1993, was a natural continuation of the series started at Cumberland Lodge, Windsor, UK in 1992. There it was decided to establish periodic discussion forums to maintain the community in close contact during these years of scarcity of neutrons. Contrary to other techniques involving either diffraction or triple axis spectroscopy, quasielastic neutron scattering has been specially affected by the dearth of dedicated instruments, which has resulted in an over-subscription several times higher than that affecting the rest of the sub-specialties (about six times more time demanded than available at high resolution spectrometers such as IRIS at the ISIS pulsed source). Under such circumstances it was reassuring to test the vitality of the field, as was clear from the contributions where new results regarding topics akin to applications in Condensed Matter or Material Sciences (Liquid and Amorphous semiconductors, Liquid Metals and Molten Salts, Orientational and Structural Glasses and Crystal-Field Excitations), Chemical Physics of Complex Systems (Polymers andColloids, Inclusion Compounds) and Biophysics (dynamics of Proteins and Complex Biological Materials).

Quantification of trehalose in biological samples with a conidial trehalase from the thermophilic fungus Humicola grisea var. thermoidea

The partially-purified, thermally-stable trehalase from conidia of Humicola grisea was highly specific for trehalose and was free of potentially interfering activities. The enzyme was fully stable when stored in solution at -15°C for at least 6 months. This preparation could be used to quantify trehalose from 0.05 to 1.25 μmol/ml either in carbohydrate mixtures or in complex biological materials.

Spectral and Temporal Resolved Emission of Eu3+ Compounds Studied with Picosecond Dye Laser Excitation

Rare earth (RE) ions are ideal configurational probes of chemical and biological molecular systems because of their sharp 4f-4f transitions, even in complex coordinational configurations. The sharp spectral characterizations of RE ions in various host materials have been exhaustively investigated by time-resolved spectroscopic techniques, although the time resolution used so far has usually been greater than nanoseconds. Recently, the use of picosecond Raman spectroscopy in the study of liquids has been reviewed. In this communication, we report the results of an experimental study of an RE ion in the solid state, to illustrate the use of a simple picosecond time-resolved spectroscopic technique. The temporal resolution permits the study of Raman and luminescence spectra under the same excitation conditions. In subsequent studies the technique will be applied to more complex biological materials, with the use of lanthanide ion probes.

Instrumentation techniques for acousto-optic studies in complex materials

Instrumentation and measurement techniques required for acousto-optic studies for complex and heterogeneous solid materials are discussed. Basic acousto-optic investigations with such techniques in hard and complex biological materials such as bone and kidney stones, as well as for other complex fibrous solid materials, are discussed in detail.

Analytical pyrolysis and environmental research

A universal method is presented for the use of pyrolysis-soft ionization mass spectroscopy and related analytical pyrolysis methods in a comprehensive characterization of complex biological and technical materials. As an example, the integrated pyrolysis-field ionization mass spectra of organic matter which occurs in different environmental compartments of the geoecological and geochemical system are presented and discussed. Furthermore, pyrolysis-field ionization mass spectroscopy is applied to the problem of current forest damage. Mass spectral fingerprints are produced for healthy and damaged spruce needles and chemometrically evaluated by pattern recognition techniques. In an integrated approach the major results are summarized and discussed together with spectroscopic, chemical, biological and geochemical data. Based on the presented overview, future fields of analytical pyrolysis studies are suggested comprising the rapid screening of contaminants in environmental samples, the early detection of chemical changes in biological materials exposed to environmental stress and the establishment of property-structure relationships.

Thermal degradation products of spruce needles

Spruce needles are analysed by in-source pyrolysis (Py)-field ionization (FI) mass spectrography and Curie-point Py-gas chromatography/electron ionization mass spectrometry. The identified thermal degradation products allow the interpretation of the FI mass signals. It could be shown that Py-FI mass spectra of plant materials are representative fingerprints which consist primarily of molecular ions of Py products derived from the thermal degradation of the main constituents of spruce needles such as carbohydrates, lignin, lipids and proteins. Primary building blocks of these biopolymers form characteristic Py products of spruce needles. Furthermore, over 500 different molecular ion species of volatilized, thermostable plant constituents are recorded using FI as soft ionization method. The present study shows that Py-FIMS is suitable for the rapid and comprehensive characterization of complex biological materials, without pretreatment of the sample except of drying and milling. The presented results contribute to the basic knowledge for the evaluation of the causes of the present tree damage.

A new multi-sample ATR-accessory for the analysis of very similar complex biological and technical materials

Measurements on complex materials are often hampered by the difficulties arising from the prerequisites to control sample uniformity. A new single- and multi-reflection ATR-accessory has been designed for the rapid analysis of many samples under extremely similar experimental conditions. This is performed by passing the ATR-unit, a horizontally mounted ZnSe-prism, by the IR-beam. It includes a gas-tight sample region. Thus, toxic material and even pathogenic bacteria may be measured under controlled conditions.

Stopping power effects in the determination of14N by a resonance reaction

The applicability of the14N(p,p’ γ1)14N nuclear reaction in the determination of the absolute abundance of14N, with a 2% uncertainty, was demonstrated at 4.3 MeV bombarding energy. The fact that almost all of the thick target γ-ray yield resulted from a resonance at Ep=4.0 MeV allowed to consider the necessary stopping-power corrections only at the energy of that resonance. Alternatively, the method was used to obtain the stopping power of 4.0 MeV protons in complex biological materials.

1] Equilibrium and kinetic inhibition assays based upon fluorescence polarization

Publisher Summary This chapter discusses the equilibrium and kinetic inhibition assays based upon fluorescence polarization. Assays, utilizing the high specificities of antibodies or other receptors make it possible to detect and quantify many substances present in only minute traces in complex biological materials. The polarization of fluorescence operates differently than the other methods of detection. In that, it gives a direct measure of the bound/free ratio instead of simply being a measure of amount of the label present. Fluorescence polarization experiments can be made, by observing, either the steady state, resulting from constant illumination of the sample or the transient state that follows a very short pulse of light. An analysis is made of the rates of the reactions that occur after preformed complexes are rapidly diluted so that the complexes dissociate to some extent and approach a new equilibrium state. The dilution jump assay affords a means of distinguishing between the specific and nonspecific interactions provided that the specific and nonspecific complexes dissociate with different rates. The assays, utilizing chaotropes to distinguish between the specific and nonspecific binding, are also discussed in the chapter.

Analysis of aldoses by gas chromatography as their 2-aminoethanethiol derivatives (author's transl)

A new and simple gas chromatographic method for the analysis of aldoses was devised. This method involves the reaction of aldoses with 2-aminoethanethiol in pyridine followed by trimethylsilylation and injection into a gas chromatograph. The peak of aldoses showed fairly good separation from the corresponding alditols. Therefore, this method was applied to the determination of the degree of polymerization of oligosaccharides, which produce alditol and aldose after reduction and hydrolysis. Since a sulfur atom is introduced into the reaction product, aldoses can be analysed by the flame photometric detector with high sensitivity, suggesting the possibility of selective analysis of aldoses in complex biological materials.

Recent advances in pyrolysis mass spectrometry of complex biological materials

Nonvolatile biological materials, such as biopolymers or even whole cells, can be made accessible to mass spectrometric analysis by pyrolysis techniques. In principle, this enables differentiation, classification and identification of these materials. Moreover, pyrolysis mass spectrometry can provide a general picture of the chemical composition and structure of the sample analysed. During the past few years we have investigated several pyrolysis techniques in combination with different mass spectrometric methods. These investigations included Curie point pyrolysis, infrared laser pyrolysis, low voltage electron impact ionization, field ionization and pyrolysis field desorption. Pyrolysis reactions were performed either at the gas inlet or directly at the ion source. The relative merits of these different experimental approaches are discussed. Additionally, examples of various applications, such as computer identification of bacteria and qualitative analyses of biopolymers, are given.

Ampicillin for sore throat.

<h3>Abstract</h3> The cytoskeleton is a collection of protein assemblies that dynamically impose spatial structure in cells and coordinate processes such as cell division and mechanical regulation. Biopolymer filaments, cross-linking proteins, and enzymatically active motor proteins collectively self-organize into various precise cytoskeletal assemblies critical for specific biological functions. An outstanding question is how the precise spatial organization arises from the component macromolecules. We develop a new system to investigate simple physical mechanisms of self-organization in biological assemblies. Using a minimal set of purified proteins, we create droplets of cross-linked biopolymer filaments. Through the addition of enzymatically active motor proteins we construct composite assemblies, evocative of cellular structures such as spindles, where the inherent anisotropy drives motor self-organization and droplet deformation. These results suggest that simple physical principles underlie the self-organization in complex biological assemblies and inform bio-inspired materials design.

The complete gas—liquid chromatographic separation of the twenty protien amino acids

The complete gas—liquid chromatographic separation of the twenty protein amino acids is presented. In our previous publications, we reported on in effective chromatographic separation of seventeen N-trifluoroacetyl n-butyl esters of the amino acids on a packing composed of stabilized grade EGA and acid-washed Chromosorb W (heated at 140° for 12 h). A new column packing has been found to replace the OV-17; it is composed of a mixed phase of OV-17 and OV-210. This is a superior packing and shows quantitative elution, and highly efficient and complete separation of histidine, internal standard tranexamic acid, lysine, arginine, tryptophan, n-butyl stearate (I.S.), and cystine. No longer is it necessary to make a separate “subtraction-calculation” for histidine. With these two packings, EGA and mixed siloxane phases, one can now simultaneously analyze and separate the 20 protein amino acids in 30 min or less with automatic electronic integration of all peaks. A second internal standard (tranexamic acid) is introduced which contains both -NH 2 and -COOH functional groups. It can be used to follow the performance of ion-exchange cleanup, thereby increasing the reliability of analysis of complex biological materials. The use of two columns for separation of the twenty amino acids has important advantages over a single column system with respect to resolution, cross confirmation, and identification of the eluted compounds.

Recent advances in the theory and practice of electrophoresis

IN ITS restricted sense the term, electrophoresis, refers to the movement of charged colloidal particles and macromolecular ions under the influence of an electric field; but recent usage includes viruses, biological cells and subcellular organelles and small organic molecules such as amino acids. Depending upon the sign of their net charge, they migrate either to the cathode or anode. Differences in migration velocities provide a sensitive means of separating substances from their mixtures which are otherwise difficult to fractionate. Indeed, electrophoresis is often the only method available for the quantitative analysis and fractionation of biological tissues and fluids and the characterization of their purified components. Likewise, it is a powerful tool for detection and characterization of macromolecular interactions. The development of electrophoresis from a chance observation by the Russian physicist Reuss [1] in 1809 to its present status as a valuable analytical method illustrates the long evolutionary process through which a physical method must often pass before it can become a routine laboratory technique. Thus, moving-boundary electrophoresis was described by Lodge [2] in 1886 and developed to a high degree of perfection for the study of transference numbers of inorganic electrolytes by MacInnes and Longsworth [3] at the turn of the third decade of this century. The first application to the study of proteins was made in 1892 by Picten and Linder [4] who showed that hemoglobin is negatively charged in alkaline solution and positively charged in acid solution. But, it was not possible to make precise measurements on purified proteins and complex biological materials until Tiselius [5] described his adaptation of the moving-boundary method in 1937. Since then, however, progress has been rapid. The abundant results obtained with the Tiselius apparatus as modified by Longsworth [6] have contributed significantly to the remarkable strides made in the past two decades in the various branches of biochemistry and medicine. With the unequivocal demonstration [7-12] in 1950 of the value of paper electrophoresis for the separation of proteins, zone electrophoresis on solid supports and in gels gained tremendous popularity. For, it is the method of choice in situations where separation rather than precise physicochemical measurements is the over-riding consideration. Furthermore, zonal methods are suitable for the analysis of very small quantities of