Recent Advances In Analytical Methods Research Articles

Recent Advances in Analytical Methods on Lipoprotein Subclasses: Calculation of Particle Numbers from Lipid Levels by Gel Permeation HPLC Using “Spherical Particle Model”

Recently, we developed an analytical method for determining the lipid levels and particle numbers in lipoprotein subclasses covering a wide size range from chylomicrons to small high density lipoproteins, by using gel permeation high-performance liquid chromatography (GP-HPLC). The challenges in analytical methods on lipoprotein subclasses have been addressed from 1980 by Hara and Okazaki using commercial TSK gel permeation columns. Later, the improvements in the hardware, separation and detection of lipoproteins, and the data processing software, using a Gaussian distribution approximation to calculate lipid levels of lipoprotein subclasses, have been extensively utilized in these analytical methods for over thirty years. In this review, we describe on the recent advances in analytical methods on lipoprotein subclasses based on various techniques, and the calculation of particle numbers from lipid levels by GPHPLC using the "spherical particle model". Free/ester ratio of cholesterol in particular lipoprotein subclass was accurately estimated from triglyceride, total cholesterol (free and esterified) and the size of the particle based on this model originally proposed by Shen and Kezdy.

トリコテセン系カビ毒検出法の近年の動向

トリコテセン系カビ毒検出法の近年の動向

Tephra without Borders: Far-Reaching Clues into Past Explosive Eruptions

This review is intended to highlight recent exciting advances in the study of distal (>100 km from the source) tephra and cryptotephra deposits and their potential application for volcanology. Geochemical correlations of tephra between proximal and distal locations have extended the geographical distribution of tephra over tens of millions square kilometers. Such correlations embark on the potential to reappraise volume and magnitude estimates of known eruptions. Cryptotephra investigations in marine, lake and ice-core records also give rise to continuous chronicles of large explosive eruptions many of which were hitherto unknown. Tephra preservation within distal ice sheets and varved lake sediments permit precise dating of parent eruptions and provide new insight into the frequency of eruptions. Recent advances in analytical methods permit an examination of magmatic processes and the evolution of the whole volcanic belts at distances of hundreds and thousands of kilometers from source. Distal tephrochronology has much to offer volcanology and has the potential to significantly contribute to our understanding of sizes, recurrence intervals and geochemical make-up of the large explosive eruptions.

Human plasma protein N-glycosylation.

Glycosylation is the most abundant and complex protein modification, and can have a profound structural and functional effect on the conjugate. The oligosaccharide fraction is recognized to be involved in multiple biological processes, and to affect proteins physical properties, and has consequentially been labeled a critical quality attribute of biopharmaceuticals. Additionally, due to recent advances in analytical methods and analysis software, glycosylation is targeted in the search for disease biomarkers for early diagnosis and patient stratification. Biofluids such as saliva, serum or plasma are of great use in this regard, as they are easily accessible and can provide relevant glycosylation information. Thus, as the assessment of protein glycosylation is becoming a major element in clinical and biopharmaceutical research, this review aims to convey the current state of knowledge on the N-glycosylation of the major plasma glycoproteins alpha-1-acid glycoprotein, alpha-1-antitrypsin, alpha-1B-glycoprotein, alpha-2-HS-glycoprotein, alpha-2-macroglobulin, antithrombin-III, apolipoprotein B-100, apolipoprotein D, apolipoprotein F, beta-2-glycoprotein 1, ceruloplasmin, fibrinogen, immunoglobulin (Ig) A, IgG, IgM, haptoglobin, hemopexin, histidine-rich glycoprotein, kininogen-1, serotransferrin, vitronectin, and zinc-alpha-2-glycoprotein. In addition, the less abundant immunoglobulins D and E are included because of their major relevance in immunology and biopharmaceutical research. Where available, the glycosylation is described in a site-specific manner. In the discussion, we put the glycosylation of individual proteins into perspective and speculate how the individual proteins may contribute to a total plasma N-glycosylation profile determined at the released glycan level.Electronic supplementary materialThe online version of this article (doi:10.1007/s10719-015-9626-2) contains supplementary material, which is available to authorized users.

Advances in analytical methods to study cholesterol metabolism: the determination of serum noncholesterol sterols

Cholesterol biosynthesis precursors and plant sterols are noncholesterol sterols currently used as relative surrogate markers of cholesterol synthesis and absorption, respectively. Its determination in serum samples is a way of diagnosing inherited disorders and also a tool for health evaluation during lipid-lowering lifestyle/drug therapy monitoring. This approach is the only one that can be used for large-scale clinical trials or population based studies, but, nevertheless, there is no reference method for the quantification of noncholesterol sterols in human serum samples and only analysis by GC-FID and GC-MS has been reported to be completely validated. Although there has been a wider use of noncholesterol sterols for the measurement and characterization of cholesterol metabolism, there is a lack of harmonization of measurements and of standardization of the methodology, which is essential for routine measurements of diagnostic utility. New recent advances in analytical methods for the determination of serum noncholesterol sterols are highlighted, focusing on the sample preparation, separation and detection techniques, which will enhance the range of applications in clinical practice.

Determination of perfluorinated compounds in aquatic organisms: a review

Bioaccumulation of PFAS in aquatic organisms is an environmental problem of growing concern around the world. This problem has been tackled by regulatory bodies by proposing EQS for biota in EU water bodies and tolerable daily intake for food. The introduction of regulatory limits requires the availability of harmonised and validated analytical methods of sufficient sensitivity. This paper reviews recent advances in analytical methods for analysis of PFAS in aquatic organisms. The methods available for biota analysis are mostly based on three extraction procedures: ion-pair extraction, solvent liquid extraction, and alkaline digestion. The resulting extracts are then subjected to different clean-up or enrichment steps on solid adsorbents, for example graphitized carbon black, C(18), and WAX phases. All methods reviewed in this work give reliable results but are partially validated only, because of the lack of certified reference materials and regular interlaboratory exercises. The few interlaboratory exercises performed on real unspiked samples did not afford satisfactory results for PFAS other than PFOS, especially for matrices with high lipid content, for example mussels. The reasons for those partially negative results have been identified, and can mainly be attributed to calibration procedures and availability and purity of standards. The urgent need for certified reference materials for this type of analysis is emphasized.

Biomass Characterization: Recent Progress in Understanding Biomass Recalcitrance

The ever-increasing global demand for energy and materials has a pronounced effect on worldwide economic stability, diplomacy, and technical advancement. In response, a recent key research area in biotechnology has centered on the biological conversion of lignocellulosic biomass to simple sugars. Lignocellulosic biomass, converted to fermentable sugars via enzymatic hydrolysis of cell wall polysaccharides, can be utilized to generate a variety of downstream fuels and chemicals. Ethanol, in particular, has a high potential as transportation fuel to supplement or even replace gasoline derived from petroleum feedstocks. Biological or enzymatic hydrolysis offers the potential for low-cost, high-yield, and selective production of targeted chemicals and value-added co-products at milder operating conditions than thermochemical processes such as gasification or pyrolysis. Due to the complex nature of biomass, degrading enzymes, and their interactions, there is a substantial knowledge gap with respect to the mechanism of enzymatic hydrolysis and the relationship between biomass structure and enzymatic performance. This knowledge gap has greatly contributed to the fact that biological conversion of lignocellulosic biomass has not met the target performance and cost requirements for large-scale production and market entrance. This review highlights recent advances in analytical methods to characterize the chemical and molecular features related to the ability of biomass to resist biological deconstruction, defined as biomass recalcitrance. We also briefly discuss the application of some of these methods in a variety of studies that draw attention to relationships between biomass structure, the effectiveness of enzymatic hydrolysis and biomass recalcitrance.

Recent Advances in Analytical Methods in Mathematical Physics

1 Division of Mechanics, Faculty of Civil Engineering, Istanbul Technical University, Maslak, 34469 Istanbul, Turkey 2 Department of Plasma Theory, Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv 03680, Ukraine 3 Department of Mathematics and Statistics, Dalhousie University, Halifax NS, Canada B3H 4R2 4 Research Laboratory for Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 5 Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117576 6 MITRE Corporation, 3101 Virginia Ave, Silver Spring, MD 20910, USA 7 Department of Electrical and Electronics Engineering, Faculty of Engineering, Trakya University, 22030 Edirne, Turkey

Pinpointing oxidative modifications in proteins—recent advances in analytical methods

Oxidation is one of the key degradation pathways in proteins and is of relevance to analyze in a wide variety of research disciplines. The types of different modifications occurring during oxidation by reactive oxygen species (ROS) are almost as many as the number of available analytical methods. Protein oxidation in biological samples has traditionally been analyzed by various proteincarbonyl assays, sometimes combined with mass spectrometry (MS) for identification of the carbonylated proteins. MS is now increasingly used also for the determination of the exact position of the oxidation in the amino acid sequence, an approach that is aided by recent developments within the field of proteomics. The following review summarizes the effects of ROS on proteins, describes methods for labeling and separation of oxidized proteins in complex mixtures, and provides insight into various MS-based methods to localize the modifications within the protein primary structure. Pitfalls with the different techniques are given, as well as examples from various applications within biological studies, protein therapeutics, plant science, the food industry and industrial biotechnology.

Current analytical methods for trichothecene mycotoxins in cereals

We review recent advances in analytical methods for trichothecene mycotoxins in cereals and cereal-based food products with emphasis on their advantages and limitations. We describe several traditional methods based on chromatographic or immunochemical techniques, which allow sensitive, accurate analysis or rapid screening of major trichothecenes throughout the cereal-food chain. In addition, we discuss novel technologies for trichothecene analysis, including tandem mass spectrometry, fluorescence-polarization immunoassays, lateral flow devices, infrared spectroscopy and optical biosensors.

Emerging Roles for Metabolic Engineering - Understanding Primitive and Complex Metabolic Models and Their Relevance to Healthy and Diseased Kidney Podocytes

The central metabolism of a cell can determine its short- and long-term structure and function. When a disease state arises, the metabolism (i.e., the transportation of nutrients into the cells, the overall substrate utilization and production, synthesis and accumulation of intracellular metabolites, etc.) is altered in a way that may permit organisms to survive under the changing physiologic constraints. Although the response of cells to injury was studied thoroughly using molecular biology and structural morphology techniques, the knowledge regarding the metabolic signatures of the disease is limited. However, recent advances in analytical methods and mathematical tools have led to new approaches to those questions with the concept of computational biology which relies on the integration of experimentation, data processing and modeling. The attempt to formulate current knowledge in mathematical terms has led to the development of several mathematical modeling tools (i.e., metabolic flux analysis, metabolic control analysis, etc.) that helps us to understand an entire biological system from basic structure to dynamic interactions. This review provides an overview and summarizes the current status of applications of mathematical models for the quantification of fluxes. A specific example of kidney podocyte cells illustrates how metabolic alterations, which occur during injury, can be used to aid in future therapeutic development. Keywords: Metabolic flux analysis, intracellular fluxes, podocyte metabolism, analysis of the health and disease

Challenges facing the development and use of protein chips to analyze the phosphoproteome

Recent advances in analytical methods, particularly in the area of protein microarrays, have brought the field of proteomics to the forefront of biological science. Protein arrays have shown to be useful for the multiplexed analysis of several hundreds of proteins in parallel. While much of the effort has focused on developing methods to identify expressed proteins, the identification of post-translational modifications is equally important for comprehensive proteome characterization. Protein phosphorylation constitutes a major type of post-translational modification that mobilizes a high number of genes, is involved in many crucial cell functions and largely contriubutes to the complexity of the proteome. One of the major challenges to analyze phosphoproteins using arrays is the availability of specific antibodies. Thus far, this has hampered the development of highly complex phosphoprotein arrays. This review discusses some of the recent progress made in the development of techniques and reagents to quantitatively determine sites of protein phosphorylation.

CAUSES OF LATITUDINAL GRADIENTS IN SPECIES RICHNESS: A TEST WITH FISHES OF THE TROPICAL EASTERN PACIFIC

Recent advances in analytical methods and exploration of regional diversity patterns in greater depth than simple whole-fauna patterns may change our understanding of the determinants of latitudinal gradients in species richness. Using a comprehensive database on the geographical distributions of the large fauna of endemic shorefishes from the Tropical Eastern Pacific (TEP), we delineated latitudinal diversity gradients (LDGs) of species with different range sizes and assessed how the mid-domain effect, energy supply, environmental variability, and habitat availability predicted the various LDGs. We used statistical methods that account for spatial autocorrelation within each variable and consider collinearity among them. We found marked variation in LDGs among species with different range sizes: species with large ranges contributed the most to the convex form of the entire-fauna LDG while species with small ranges generated most deviations from that form. The mid-domain effect was the strongest determinant for the entire-fauna LDG, largely due to the strength of its effect on widespread species. Habitat variables were the best predictors for LDGs of small-range species but had no significant effects on the entire-fauna pattern. We found that any relationship between energy supply and LDGs likely is spurious and arises from statistical effects of (1) the marked spatial autocorrelation of the residuals in those relationships and (2) strong covariation between energy supply and the mid-domain effect, two factors that have never been analyzed together in marine studies (and seldom in terrestrial studies). There was no indication that environmental stability was an important LDG determinant at any level within the fauna. We found that latitudinal (Rapoport) trends in range size in this fauna arise as corollaries of the mid-domain effect. The disparate contributions of species with different range sizes to diversity patterns demonstrate the failure of traditional, whole-fauna LDGs to adequately represent all faunal components and their determinants, particularly those of small-range (and more threatened) species. We argue that, just as analyses of whole-fauna patterns within a region obscure variation in determinants among faunal components, analyses of patterns at transoceanic (multiregional) scales are likely to conceal important regional variation in determinants of diversity gradients.

Recent advances in analytical methods for mycotoxins

Recent advances in analytical methods for mycotoxins

Heterogeneity in the clonal T cell response. Implications for models of T cell activation and cytokine phenotype development.

The T cell can be defined in the context of two properties--the recognition specificity of the T cell receptor (TCR) heterodimer and the functional response of the T cell after TCR stimulation. Once a particular TCR heterodimer is expressed and successfully selected during thymic development, the antigen specificity is fixed for all the clonal progeny of that cell. In contrast, the potential functional responses that may be generated in response to specific antigen in the postthymic environment are quite extensive. These range from programmed cell death to initiation of alternate programs of phenotype development that generate effector populations with distinct cytokine expression patterns and regulatory properties. Recent advances in analytical methods that have permitted multiparametric characterizations of the T cell response at the single cell, rather than population level, have necessitated a modified view of T cell activation and the clonal T cell response, and have generated new insights into the regulation of immunity. In this brief review, we highlight studies that have characterized heterogeneity of the CD4+ T cell clonal response based on single-cell analyses, and discuss implications for models of T cell activation and cytokine phenotype development.

An introduction to electrospray ionization and matrix‐assisted laser desorption/ionization mass spectrometry: Essential tools in a modern biotechnology environment

The tremendous progress in biochemistry and biotechnology has been made possible in part by recent advances in analytical methods, in particular mass spectrometry. With the introduction of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI), mass spectrometry allowed the determination of the molecular weight of peptides and proteins with a much greater accuracy than achievable by traditional methods such as SDS-PAGE and biogel chromatography. In addition, these mass spectrometry experiments have become routine and can be performed within minutes. ESI and MALDI (in combination with enzymatic methods) can also provide vital structural data such as the amino acid sequence and the sites of posttranslational modifications for peptides and proteins with a sensitivity that competes favorably with other methods. The use of ESI and MALDI is not limited to peptides and proteins; analysis of oligonucleotides and oligosaccharides has been simplified by these techniques as well. For information about structurally significant noncovalent interaction between various types of biomolecules, ESI is probably one of the most convenient methods. Not surprisingly, we anticipate that the mass spectrometers with these ionization capabilities will soon become standard equipment in all pharmaceutical and biotechnology laboratories. © 1997 John Wiley & Sons, Inc. Biospectroscopy 3: 259–280, 1997

Recent advances in analytical methods for mycotoxins.

Recent advances in analytical methods are reviewed using the examples of aflatoxins and trichothecene mycotoxins. The most dramatic advances are seen as being those based on immunological principles utilized for aflatoxins to produce simple screening methods and for rapid specific clean-up. The possibilities of automation using immunoaffinity columns is described. In contrast for the trichothecenes immunological methods have not had the same general impact. Post-column derivatization using bromine or iodine to enhance fluorescence for HPLC detection of aflatoxins has become widely employed and there are similar possibilities for improved HPLC detection for trichothecenes using electrochemical or trichothecene-specific post-column reactions. There have been improvements in the use of more rapid and specific clean-up methods for trichothecenes, whilst HPLC and GC remain equally favoured for the end-determination. More sophisticated instrumental techniques such as mass spectrometry (LC/MS, MS/MS) and supercritical fluid chromatography (SFC/MS) have been demonstrated to have potential for application to mycotoxin analysis, but have not as yet made much general impact.

Recent Advances in Analytical Methods of Gene Engineering

Recent Advances in Analytical Methods of Gene Engineering

Arsenic species as an indicator of redox conditions in groundwater

Although the thermodynamically based concept of oxidation-reduction potential has for many decades been an accepted tool for interpretation of the chemistry of hydrochemical systems, attempts at measurement of actual redox levels in natural waters have been fraught with difficulty. Existing methods of measurement involve use of potential-sensing inert metal electrodes or analytical determination of redox-indicator species such as dissolved O 2 or Fe 2+ or redox couples such as SO 2− 4-HS − and HCO − 3-CH 4. As a result of recent advances in analytical methods, it is now possible to determine the concentrations of both As(III) and As(V) at sufficiently low levels so that the apparent redox condition, as pE or Eh, can be computed from measured concentrations of As(III) and As(V) species. The arsenic pE or Eh domain obtained using published thermodynamic data for As species and the assumption of redox equilibrium, provides a basis for obtaining an indication of redox levels within the central portion of the redox field for natural waters. The redox domain for the As couple is largest at high total dissolved As concentrations, but even at concentrations as low as 1–10 μg/l the domain has significant extent. Oxidation and reduction of As(III) and As(V) in laboratory trials with redox agents common to natural waters, such as O 2, H 2S and Fe, suggests that oxidation or reduction of As species in natural waters occurs at rates sufficiently slow to enable water samples to be collected, transported and analysed before excessive change in species distribution takes place, but rapid enough for As species to adjust to the dominant redox condition of the water if periods of years or longer are available for equilibration. Because of the long equilibration time and the position of the pE-pH domain for the As couple, groundwater is best suited for use of As as a redox indicator.

The Facilities Layout Problem in Perspective

The relative location of facilities in a functional layout has been determined under the criterion of materials handling cost minimization. Recent advances in analytical methods have provided superior solutions within this criterion hut the validity of certain underlying assumptions must be questioned. Materials handling as a criterion is deficient for many facilities layout problems; yet a modified definition of "materials" may yield considerable insight to the improved location of people. Each layout problem is made unique by its particular assumptions, constraints, limitations, and the intrinsic activity of the components; a guide to establishing this uniqueness and to selecting appropriate tool3 for analysis is presented.