bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phillipine natural grade carrageenan
Authors: Tye R J 
Published: November 2023

Abstract
Commercially, carrageenan is produced by two technologies giving rise to “Traditionally Extracted Carrageenan” and “Natural Grade Carrageenan”. The traditional extraction processes (alcohol, gel press and roll dried) involve boiling the seaweed in alkali to dissolve the carrageenan. Depending on concentration, the solutions may be subjected to viscosity control so that the liquor can be pumped and filtered and then coagulated in alcohol or potassium chloride solution giving rise to two distinct precipitated products known as alcohol and gel press carrageenan. Natural Grade Carrageenan is produced by steeping freshly harvested weed in alkali at moderate temperature. The process does not involve dissolution of the carrageenan which is protected by the seaweed’s inert cellulose matrix. The traditional process is energy intensive and produces considerable quantities of pollutants which have to be dealt with at great expense. Natural Grade Products (or Alternatively Refined products as they are often called), do not carry this overhead and are thus much more cost effective. The only chemical difference between alcohol precipitated products and the Philippine materials is the presence of inert cellulose. The active polysaccharides cannot be distinguished by any known chemical or spectroscopic techniques. Gel press materials are readily identifiable by their high potassium chloride content.
Processing optimization and physico-chemical characteristics of flaxseed polysaccharide gums
Authors: Cup W , Mazza G , Biliaderis C G 
Published: November 2023

Abstract
Response surface methodology was used to optimize the aqueous extraction of polysaccharides from flaxseed. Temperature, pH and seed/water ratio were the major parameters affecting yield, chemical composition and rheological characteristics of the crude gum extract. Optimum conditions for extraction were a temperature of 85-90°C and a neutral pH (6.5-7). Seed/water ratio had a smaller effect on yield and properties of flaxseed gum than temperature and pH. Flaxseed gum extracted under optimum conditions gave relatively high yield (7.9%) and contained over 80% carbohydrates. Using ion exchange chromatography, on a DEAEcellulose column, the crude flaxseed gum was dialyzed and further separated into a neutral and an acidic fraction. Protein content, minerals, monosaccharide composition and uronic acid levels of flaxseed gum fractions were determined. Further structural information and molecular size distributions of the gum and its fractions were obtained by methylation analysis, 13C NMR and gel filtration chromatography. Flaxseed polysaccarides exhibited shear thinning and weak gel properties at concentrations above 1% (w/w). The neutral flaxseed gum fraction (NFG) was of higher molecular size and showed similar shear thinning behavior as the crude and dialyzed gums. The acidic fraction, on the other hand, consisted of low molecular size polymers and exhibited Newtonian-like flow behavior.
Computer optimisation of parameters for the preparation of low viscosity guar gum by controlled thermal and acid hydrolysis
Authors: Mathur V , Kanoongo N , Mathur N K 
Published: November 2023

Abstract
Galactomannan polysaccharides when treated with acid catalysts at elevated temperatures, are depolymerised to products of lower viscosities and lower molecular weights. The extent of depolymerisation has to be controlled to obtain a product of predetermined characterstics. Various factors which control the extent of depolymerisation include, besides the reaction time, the temperature of reaction and the concentration of the catalyst, certain other factors e.g. the design of the reactor, rate of mixing/stirring and the gum itself (powder or split). For a given set of experimental conditions, computer optimisation can be done to find suitable sets of conditions for actual working.
Nutritional aspects of difficult-to-digest carbohydrates
Authors: Livesey Geoffrey 
Published: November 2023

Abstract
The chemical composition, structure and intakes of diets tl maintain optimal physiological function, and health, is st ill-defined. Reference requirements of the UK population over 40 nutrients have been suggested and nutritional guides: can be based on such values (1)he attributes of an opted diet for one individual may, however, differ from that another. Individuals who are predisposed by genetics lifestyle to disease may need to be more concerned about th diet than non-predisposed individuals. In such individuals may well be that therapeutic levels of specific nutrients well above those needed by the general population. Most evide relating diet to health is concerned with general populations individuals in disease, whereas it is likely that information.
Influence of galactomannan addition on the viscoelastic properties of pectin-calcium systems
Authors: Silva J A , Lopes Da , Gon&lt;Alves M P , Doublier J L , Axelos M A V 
Published: November 2023

Abstract
The influence of galactomannan addition on the formation of low methoxyl pectin/calcium networks, with different density of crosslinks, was studied through the changes in the mechanical spectrum obtained from dynamic shear measurements. The mixed gels showed an increase in the storage and loss moduli with the increase of galactomannan concentration, especially at high frequency. The pectin/calcium network remains the continuous gel matrix controlling the viscoelastic behaviour of these systems at low frequency. The effect of galactomannan addition on the viscoelastic behaviour of the mixed gels at “equilibrium” depends on the structure of the pectin/calcium network. We suggest that there is no specific interaction and that the changes in the mechanical properties of the pectin gels are due to the entrapment of the galactornannan macromolecules in the pectin-calcium network. One interesting aspect is the decrease of the tendency for the pectin/calcium gels to undergo syneresis, by the addition of the galactomannan.
Technological impact on foam stability: analysis of quality assurance data with multivariate analysis
Authors: Lebouille J L M , Moonen H A J 
Published: November 2023

Abstract
The use of multivariate data analysis techniques, applied to quality assurance data of fermentation and lagering, to elaborate technological aspects of foam stability is described. In multivariate data analysis, co-linearities between variables are extracted and suppressed. During the fermentation the addition of more than one brew in a tank contributes negatively to the foam stability. In the lagering process comparable negative aspects were found.
Patch-clamp recording
Authors: Gibb Alasdair J 
Published: November 2023

Abstract
Patch-clamp recording is now widely used in the biological sciences. The technique was originally developed with the very specific intention of observing ionic currents flowing through single ion channels in cell membranes (1). From this origin the technique has developed into one of the most versatile and precise methods of measurement in biology. For example, no other technique allows the observation of the functioning of a single protein molecule in a lipid bilayer, yet can also allow monitoring of synaptic transmission between neurones in the brain, or permit monitoring of the change in cell membrane area during secretion. Underlying all the applications of patch clamping is the single principle that it provides an extremely sensitive means to measure ionic currents flowing through cell membranes. For their discovery and development of this technique and its application to a range of critical questions in biology, Neher and Sakmann were awarded the 1991 Nobel prize in Physiology or Medicine (1, 2, 3). Two excellent sources of detailed information on the patch-clamp technique are available: the ‘blue book’ guide to patch-clamp recording (4, a new edition of this book is due in 1995) and the recent ‘Ion channels’ volume of Methods in enzymology (5). In recent years various aspects of the patch-clamp technique have been reviewed in several different articles and books (6, 7, 8, 9). This chapter is intended to provide an overview, concentrating on the more practical aspects of the patch-clamp technique.
Avian ciliary and Ium bar sympathetic ganglion neurons
Authors: Nishi Rae 
Published: November 2023

Abstract
Chick parasympathetic and sympathetic ganglia provide a convenient source of readily isolated and cultured neurons that have a variety of uses: bioassays for trophic factors by quantifying survival of neurons in response to defined or undefined activities bioassays for neurite outgrowth promoting activities bioassays for neurotransmitter plasticity In particular, the chick ciliary ganglion is a relatively homogeneous source of cholinergic parasympathetic neurons that innervates striated muscle very readily, hence it has been invaluable for studies of molecular changes associated with neuromuscular synapse formation.
Mouse olfactory epithelium
Authors: Calof Anne L , Guevara Jose L , Gordon Melinda K 
Published: November 2023

Abstract
The olfactory epithelium is unique in mammals in that proliferation of neuronal precursor cells and differentiation of their progeny into olfactory receptor neurons (ORNs) continue throughout the lifetime of the organism (1,2). Many of the studies in our laboratory are concerned with understand ing how specific polypeptide growth factors and cell interactions regulate olfactory receptor neuron generation and survival (3-6). For these studies it is crucial to obtain and culture explants of olfactory epithelium that are free from stromal cells, since the stromal cells may provide signals that affect the development of olfactory receptor neurons. Thus, an entire section of this chapter is devoted to purification of the epithelium from its underlying stroma. For studies of growth factor effects on isolated ORNs, and for studies on olfactory receptor neuron adhesion, migration, and axon outgrowth, we prepare a neuronal cell fraction from embryonic mouse olfactory epithelium, as well as using explant cultures. This neuronal cell fraction consists solely of olfactory receptor neurons and their precursors, which we have called the immediate neuronal precursors (INPs) of olfactory receptor neurons, and does not contain basal cells or supporting (sustentacular) cells of the epithelium (6–8). Using this cell fraction allows us to work solely with neuronal cells in dissociated cell culture, which is a great advantage for quantitative studies.
RNA binding assays for the regulatory proteins Tat and Rev
Authors: Karn J , Churcher M J , Rittner K , KELLEY A , Kelley P J G , Mann D A , Gait M J 
Published: November 2023

Abstract
The replication of the human immunodeficiency virus (HIV) is controlled by two viral proteins, Tat, the trans-activator protein and Rev, the regulator of virion expression. The two proteins play complementary roles in the HIV life cycle. In permissive cells, transcription of the integrated proviral genome is initiated by host cell transcription factors (1-3). Initially, only small, multiply spliced mRNAs including the mRNAs for Tat and Rev are produced (4). Tat synthesized during this primary round of transcription then establishes a ‘positive feedback loop’ which boosts mRNA production 200- to 1000-fold (5- 7). Once a critical Rev threshold is surpassed, HIV gene expression switches away from the production of the mRNAs for the regulatory proteins towards the production of the unspliced or partially spliced mRNAs encoding the virion proteins (8-10).
Vif
Authors: Trono Didier 
Published: November 2023

Abstract
The HIV-1 vif open reading frame (previously called ‘sor’ or ‘A’) encodes a protein of 192 amino acids, with an approximate molecular weight of 23 kDa. Vif is highly conserved among different HIV-1 isolates. Vif is also present in HIV-2 and simian immunodeficiency virus, and in non-primate lentiviruses, such as feline and bovine immunodeficiency viruses, caprine arthritis encephalitis virus, and visna virus, a cytopathic lentivirus of sheep only distantly related to HIV. HIV-1 Vif is translated from a singly spliced viral mRNA, together with other late viral proteins whose expression is induced by Rev. Initial studies showed that HIV-1 strains defective in vif generated virions that infected cells approximately a 1000 times less efficiently than wild-type viruses, hence the acronym Vif, for virion infectivity factor.
Inhibition of HIV by ribozymes and antisense oligonucleotides
Authors: Castanotto D , Bertrand E , Rossi J 
Published: November 2023

Abstract
Introduction
Since the early 1980s, when the immunodeficiency virus (HIV) was shown to be the etiological agent of AIDS, a considerable amount of information on its life cycle has been collected. Although this growing body of knowledge has allowed investigators to evolve rational drug designs, the complexity of HIV has so far made it impossible to develop a cure or a vaccine. The variety of tissues and cells which HIV is able to infect, along with the high mutation rate of the viral genome and the secondary diseases associated with AIDS, further restrict the possibilities for achieving any effective therapy. Moreover, agents that block viral function often have adverse effects on the host, especially after prolonged use. A relatively new approach in the treatment of viral infections is the use of antisense and/or ribozymes in the attempt to bind and block expression of viral transcripts. To date, they have been reported to be effective in cell cultures against viral targets, oncogenes, and transfected genes. RNA enzymes or ribozymes are receiving considerable attention because, unlike antisense, ribozymes are able to turn over multiple substrates and inactivate them irreversibly. The ribozyme technology is based on the design of RNA molecules in which the antisense and enzymatic functions are combined into a single transcript, which can specifically pair and cleave any target RNA. Because of their high specificity and the possibility of being endogenously synthesized within a cell, it is likely that ribozymes will be major players in the development of new drugs during the next several years.
Gene therapy
Authors: Smith C , Marasco W A , Bohnlein E 
Published: November 2023

Abstract
Somatic gene therapy was independently proposed in 1988 by D. Baltimore and J. C. Sanford as an alternative treatment of AIDS (1, 2). This new approach is based on the stable introduction of genetic material into cells of HIV-I-infected patients. The therapeutic genes can be delivered directly into the target cells of HIV in the peripheral blood (CD4-positive lymphocytes, macrophages) using techniques analogous to those used for the first human gene therapy trial for the treatment of AD A deficiency. Differentiated peripheral blood cells have a limited life expectancy and repeated treatment would be required. Alternatively, the antiviral genes can be introduced into the haematopoietic stem cell from which all HIV-1 target cells are derived. In this case, a single treatment could suffice to obtain the therapeutic effect.
Labelling methods for analysis of class II MHC endocytosis and peptide turnover
Authors: A.Reid Pamela , Watts Colin 
Published: November 2023

Abstract
MHC glycoproteins are peptide binding and transport proteins which give a continual update, in peptide form, of the cellular and environmental protein composition on class I or class II MHC molecules respectively (see ref. 1 for a review). Cells expressing these molecules can therefore be screened by T lymphocytes for the presence of foreign peptides. A response will only be elicited if the level of a particular peptide/MHC complex is above the threshold needed for activation of the responding T cells. Whether this threshold is reached will depend on the relative rates of production and loss of peptide/MHC complexes from the cell surface. Production rates will be governed by variables such as the rate of MHC biosynthesis, level of antigen expression or capture and efficiency of antigen processing etc. (2). Rates of loss will depend on (i) the absolute lifetime on the cell surface of MHC molecules and (ii) the lifetime of particular peptide species on MHC molecules. Clearly, if the lifetime of peptides on MHC molecules is much longer than the absolute lifetime, loss rates will simply reflect how long MHC molecules reside on the cell surface. On the other hand, if peptide lifetime is much shorter than absolute MHC lifetime on the cell surface then the rate of loss of complexes will be largely independent of absolute lifetime. This latter scenario raises the possibility that the ‘empty’ MHC molecules generated might be re-used to present additional peptides during their tenure on the cell surface. Since peptide production for MHC binding is not thought to occur on the cell surface, an endocytic cycle of some kind would seem to be necessary to permit re-utilization.
Peptide translocation into the ER
Authors: Neefjes Jacques , Momburg Frank , Ha.Mmerling Gunter , Roelse Joost 
Published: November 2023

Abstract
A crucial step in antigen presentation by MHC class I molecules is the translocation of peptide fragments of protein antigens from the cytosol to the lumen of the endoplasmic reticulum (ER). Here, peptides are bound with high affinity by freshly assembled MHC class I H-chain/l32m heterodimers and are then intracellularly transported to the cell surface and presented by class I molecules to cog+ T cells (1, 2). An ER-located peptide pump termed TAP (Transporter associated with Antigen Presentation) has been genetically defined and demonstrated to translocate peptides from the cytosol to the lumen of the ER (3, 4). Essential to the characterization of TAP were mutant cell lines with inactivated genes for one or both of the two subunits of TAP. In the absence of TAP activity, MHC class I molecules are not loaded with peptides. This results in retention of the class I heterodimer in the ER and decreased cell surface expression of class I molecules.
The interaction of superantigens with MHC class II molecules
Authors: Horgan Carol , Fraser John D 
Published: November 2023

Abstract
Superantigens are specific viral or bacterial products that simultaneously bind to class II MHC molecules and T cell receptors (TCR) without requiring proteolytic processing. They can activate up to 20% of peripheral T lymphocytes, as compared to conventional antigens which activate only about 0.001% of peripheral T cells. The binding occurs at sites on the MHC outside of the peptide binding groove and on the chain of the TCR, away from the conventional antigen binding site.
Methods for the generation of T cell clones and epithelial cell lines from excised human biopsies or needle aspirates
Authors: Libero G De 
Published: November 2023

Abstract
The effector mechanisms and the cellular interactions that regulate the immune response can be studied by taking advantage of defined in vitro systems. These studies can be performed using cloned reagents, such as T cell clones and monoclonal antibodies (mAbs). Studies performed with T cell clones have allowed the identification of surface molecules involved in cellular interactions (1-7), of lymphokines responsible for immunoregulation (8), and of different functional properties of T cells (9, 10). T cell clones have also facilitated the analysis of the molecular requirements for antigen presentation (11-13), antigen recognition (14), and T cell activation (15), and are a unique source of nucleic acids for the characterization of the genes that are expressed only in rare lymphocytes (16, 17).
Techniques to identify the rules governing class II MHC-peptide interaction
Authors: Hammer J , Sinigalia F 
Published: November 2023

Abstract
Major histocompatibility complex class II molecules (MHC) are highly polymorphic membrane glycoproteins that bind peptide fragments of proteins and display them for recognition by CD4+ T cells. The binding capacity of any given peptide to an MHC class II molecule depends on the primary sequence of the peptide and on allelic variations of residues in the binding site of the MHC receptor. Advances in our knowledge of the structure of MHC molecules, and a large number of peptide and MHC class II structure-function studies have provided an increasingly detailed picture of how allelic variations influence peptide binding and presentation to CD4+ T cells (1).
Detection of free radical reaction products by high-field nuclear magnetic resonance spectroscopy
Authors: Naughton D P , Lynch E , Hawkes G E , Hawkes J , Blake D R , Grootveld M 
Published: November 2023

Abstract
Nuclear magnetic resonance (NMR) spectroscopy uses the absorption of energy from the radiofrequency region of the electromagnetic spectrum to detect changes in the alignment of nuclear magnets during exposure to a powerful external magnetic field. The absorption frequency is dependent on the magnetic (and, therefore, chemical) environment of nuclei. Furthermore, the appearance (multiplicity) of a resonance in the 1H (proton) NMR spectrum of a particular chemical component is influenced by neighbouring hydrogen nuclei in a well-characterized way. Hence, much useful information about the molecules present in a biological sample can be obtained from NMR spectroscopic techniques.
Visual assessment of oxidative stress by multifunctional digital microfluorography
Authors: Suematsu Makoto , Schmid-Schönbein Geert W , Ishimura Yuzuru , Tsuchiya Masaharu 
Published: November 2023

Abstract
There has been an increase in the understanding of the potential role of oxidants, such as the superoxide anion (OD, hydrogen peroxide (H202), hydroxyl radicals COH), as mediators of cell injury in a wide variety of physiological and pathophysiological conditions. These active oxygen metabolites can interact with cellular membrane structures thereby inducing lipid peroxidation, which has been implicated as one of the major mechanisms of ‘oxidative stress’ in tissue injury. By contrast, the nitric oxide radical (NO”), which has been identified as an endothelium-derived relaxing factor, plays an indispensable role in the maintenance of blood perfusion and antithrombotic properties of vascular endothelium, and contributes as a natural antioxidant to scavenging superoxide anion. Under some pathological conditions, the interaction between NO” and 02 may yield peroxynitrite (ONOO-) and thereby promote cell injury.
Protein hydroperoxides, protein hydroxides, and protein-bound DOPA
Authors: Dean Roger T , Fu Shanlin , Gieseg Steven , Armstrong Sharyn G 
Published: November 2023

Abstract
Other chapters in this volume describe the determination of stable, relatively unreactive products of protein oxidation, such as protein carbonyls. How ever, we have recently shown that radical attack on proteins can generate two kinds of reactive moieties that are fairly long-lived under appropriate conditions: protein hydroperoxides (oxidizing species) and protein-bound DOPA (3,4-dihydroxyphenylalanine) (a reducing species (1, 2); reviewed in ref. 3).