Search

Cephalopods are fast-growing animals, active swimmers and top predators, which require substantial amounts of food. As such, they show high metabolic rates dependent on a carnivorous diet, thus hypothetically linked to a predominant amino acid metabolism. Their body composition is mainly constituted by high levels of total protein, and their lipids, although quantitatively low, reveal the presence of substantial amounts of long-chain polyunsaturated fatty acids. All in all, little is known about their nutritional requirements, especially during the early stages, very prone to high mortalities under culture. This chapter is a brief account of key information concerning relevant points linked to the nutritional requirements that cephalopods have for proteins, lipids, carotenoids, carbohydrates, minerals and vitamins. Moreover, some considerations on populational metabolism are also presented. [ABSTRACT FROM AUTHOR]

Molecular fossils can be a useful source of information about past -organismic physiology and an effective tool for reconstruction of paleoenvironmental conditions. This is particularly the case with Precambrian sediments, which only rarely contain visible fossils. However, since these most ancient of rocks are frequently thermally altered and contain low contents of organic matter, analytical uncertainties and concerns surround the syngeneity of biomarkers. Analysts must be vigilant in recognizing and avoiding contamination by hydrocarbons derived from more recent organisms. Here we present an overview of the current state of Precambrian molecular paleontology and provide a theoretical and practical entrée into the field of organic geochemistry. We discuss improved strategies and analytical- methodologies including a guide to interpreting data as well as recognizing- and avoiding contamination. [ABSTRACT FROM AUTHOR]

Metabolomics is developing toward an integral component of functional genomics approaches. The large structural diversity of plant metabolites requires different analytical techniques for broad metabolite analysis. In addition, new bioinformatics tools and databases are necessary for data analysis and storage. This chapter describes the resources available for comprehensive analysis of plant secondary metabolites focusing on Arabidopsis thaliana and Brassica species. In particular, a platform for non-targeted profiling of semi-polar plant metabolites based on liquid chromatography coupled to mass spectrometry is described. [ABSTRACT FROM AUTHOR]

· The effect of nutrition on human health has received tremendous attention and traditional medical teaching that diet and nutrients play only limited roles in human health is being revised. · Toxic products of food oxidation during food processing, storage, and cooking are the major determinants of the detrimental effects of various foods on human health. · Flavor is the trait responsible for consumer preferences for meat and meat products while lipid oxidation during prolonged storage or short-term exposure to high temperatures is often associated with off-flavors. · Lipid oxidation is a major problem in the storage of fatty foods affecting its quality and safety. Changing flavor, color, and texture results in significant generation of cytotoxic and genotoxic compounds and co-oxidizes many vitamins so that improvement of conditions of food processing, storage, and cooking is a frontline of future research. [ABSTRACT FROM AUTHOR]

Cigarette smoke, the prototypical form of oxidative stressor for the vascular system, is a complex mix of thousands of oxidative and nonoxidative compounds. Although it is still not clear which smoke chemicals are responsible for CVD initiation and progression, some important chemicals have been identified. Importantly, many cigarette smoke chemicals increase the oxidative burden for the vasculature directly, but also indirectly, e.g., by causing cellular damage and inflammation. The processes underlying the impact of smoking on CVD initiation and progression is discussed in this chapter. [ABSTRACT FROM AUTHOR]

The progression of both atherosclerosis and glomerulosclerosis follows similar pathways. An initial injury leads to an enhanced endothelial transcytosis of low-density lipoprotein (LDL) in the subendothelial space. Lipid accumulation by macrophages engenders formation of foam cells. Activated endothelial cells induce inflammation through the release of monocyte chemoattractant protein 1. This stimulates the influx of monocytes to the intima/glomerulus and exacerbates vascular/glomerular injury by releasing chemokines and cytokines. The initial stage of inflammation leads to interactions between infiltrating and resident cells mediated through release of a range of mediators, including chemokines, cytokines, vasoactive peptides, growth factors, and reactive oxygen species (ROS). Further, activation and proliferation of vascular smooth muscle cells (VSMCs) and mesenchymal mesangial cells and their synthesis of the extracellular matrix (ECM) contribute to the fibrotic process. The final fibrotic phase results from an imbalance between ECM synthesis and degradation, leading to irreversible sclerosis. [ABSTRACT FROM AUTHOR]

It is well known that classical energy sources such as petroleum oil and natural gas make up the fundamental materials, on which all modern industrial chemical parks are based on. According to the finiteness availability of these consuetudinary resources and due to the increasing demand for energy of developing countries and the related rise in prices of oil and natural gas, renewable resources must be considered as valuable alternatives. Discussions about climate changes with regard to alternatives of energy production are very fervid but alternatives have to be examined from a matter-of-fact based, economical, and scientific point of view. Within the frame of this contribution, we focus therefore on alternative sources with respect to their potential as future building blocks for chemical synthesis processes. [ABSTRACT FROM AUTHOR]

Chapter 12 of the book "Fast Facts: Hyperlipidemia," fourth edition, by Allan Sniderman and Paul Durrington is presented. It explores the variations in clinical lipid testing procedures in terms of methodology and biology. It mentions the use of enzymatic techniques in the measurement of cholesterol. Furthermore, it also examines the measurement of serum triglycerides through enzymatic methods.

Chapter 2 of the book "Fast Facts: Hyperlipidemia," fourth edition, by Allan Sniderman and Paul Durrington is presented. It explores the epidemiology and pathophysiology of lipids and lipoproteins. It examines the relationship between high cholesterol and coronary disease. Furthermore, it also mentions the entry of atherogenic lipoprotein particles in the arterial wall depending on its size and number.

Chapter 1 of the book "Fast Facts: Hyperlipidemia," fourth edition, by Allan Sniderman and Paul Durrington is presented. It explores the structure and physiology of lipoproteins. It also examines the production and composition of several types of lipoprotein particle including Chylomicrons, very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). Furthermore, it also examines the structure and composition of apolipoprotein (apoB).

This chapter discusses engineering of plants for yield and composition of edible and industrial triacylglycerols (TAGs). Total oil production has been increased moderately by overexpression of genes for the first and last steps of oil synthesis, acetyl-CoA carboxylase (ACCase), and diacylglycerol acyltransferase (DGAT), respectively. However, the single enzyme approach has proved less than satisfactory, and further progress may depend on identification of regulatory genes affecting overall expression of the lipid synthesis pathways and partitioning of carbon between oil and other plant products. The fatty acid composition of oilseeds has been more amenable to modification. Development of edible oils rich in monounsaturated fatty acids (18:1) has been achieved in several oilseeds normally dominated by polyunsaturated fatty acids such as 18:2. Approaches have included both chemical mutagenesis and transgenic alteration of the FAD2 genes responsible for desaturation of 18:1 to 18:2. Proportions of 16:0 have been reduced substantially by reduction of FatB, the gene for the thioesterase that releases 16:0 from the acyl carrier protein (ACP) on which it is assembled. The last major goal in edible oil modification, production of a temperate crop sufficiently rich in saturated fatty acids for use without hydrogenation and its associated trans-fatty acid production, remains elusive. Mechanisms for minimizing transfer of the upregulated saturated fatty acids to plant membranes are currently lacking. Excess saturated fatty acids in plant membranes are particularly damaging in colder temperature ranges. Finally, a wide range of genes have been identified that encode enzymes for synthesis of unusual fatty acids with potential as food additives or industrial feedstocks. Genes for production of γ-linolenic acid (GLA) and polyunsaturated ω-3 fatty acids have been introduced into plants, as have genes permitting production of 10:0 and 12:0 for the detergents industry, longchain fatty acids for plastics and nylons, novel monounsaturated and conjugated fatty acids, and fatty acids with useful epoxy-, hydroxy-, and cyclic moieties. With the notable exception of the shorter-chain fatty acids, these efforts have been hampered by inadequate yields of the novel products. Given that plants from which many of the applicable genes were isolated do produce oils with high proportions of unusual fatty acids, increased yields in transgenic crops should be achievable. It is probable that introduction of the novel fatty acids must be coupled with appropriate modifications of the enzymes responsible for their flux into vegetable oils. [ABSTRACT FROM AUTHOR]

‘Unting is all that's worth living for – all time is lost wot is not spent in ‘unting – it is like the hair we breathe – if we have it not we die – it's the sport of kings. The most vital possessions of the plant are the chloroplasts in the cells of its leaves. Through these, the organism can convert, for its own purposes, a fraction of the solar energy that falls upon it. Sunlight is remarkably uniform in its intensity, and a plant has little to gain by moving about. It can thus afford a relatively stationary existence, the only motion being that required to reach regions beyond the shade of its immediate environment and its competitors. Because they have no chloroplast-bearing cells, animals have paid the penalty of having to develop several specialized functions in order to satisfy their energy requirements. They must have a means of locomotion and feeding, and some form of coordination of these faculties, however primitive, is needed. And as insurance against the unsuccessful forage, they should be able to store digested energy. Moreover, unless an animal is so small that the normal process of diffusion is adequate, it must have a circulatory system to distribute dissolved gases and chemical compounds to its various parts. [ABSTRACT FROM AUTHOR]

'tis, we musicians know, the C Major of this life. Paintings and museum reconstructions depicting the activities of medieval alchemists can easily give the wrong impression of the chemical knowledge of that period. Inanimate objects such as crystals are seen sharing shelves with the preserved bodies of small creatures, a common feature of the early laboratory. This could be taken to suggest that the scientists of those days had grasped the unity of chemistry: that in spite of great differences in their external appearance, Nature makes no distinction between chemical combinations in living and dead substances. Nothing could be farther from the truth. The universally held belief was that the matter contained in living organisms possessed an essential extra ingredient, a vital force, the mysterious origin of which was attributable to divine powers. This attitude was epitomized in the succinct classification to be found in the book Cours de Chyme, published by Nicholas Lemery in 1685. His division is still to be found in the standard first question of a popular parlour game: ‘animal, vegetable or mineral?’. By the end of the eighteenth century, the vital force theory was in rapid decline. Antoine Lavoisier, analyzing typical organic compounds, found them to contain inorganic substances such as hydrogen, oxygen, nitrogen, carbon, sulphur and phosphorus. The basic principles that govern chemical change, such as conservation of total mass, were being established during this period, and in 1844 Jöns Berzelius showed that they apply to all matter irrespective of whether it is inorganic or organic. [ABSTRACT FROM AUTHOR]

There is no excellent beauty that hath not some strangeness in the proportion. Most substances can exist in three different states: solid, liquid and gas. The temperature, pressure and density collectively determine which form is adopted, and changes in the imposed conditions can produce the melting and boiling phase transitions. The solid state is usually crystalline, but some solids have the meta-stable glass structure. Differences between the three fundamental states are often depicted by simple diagrams in which atoms are represented by circles. For a gas, the circles are drawn randomly, with the distance between neighbouring circles somewhat larger than the circle diameter. The condensed states, crystal and liquid, are illustrated by arrangements in which the distances between the centres of neighbouring circles are comparable to the diameters, the difference between these forms lying mainly in the regular arrangement of the former and the relative randomness of the latter. We can go a long way with such models because real atoms are indeed roughly spherical. This is particularly true for noble gases such as argon and neon, because of their closed electron shells, but it is a reasonable approximation for all atoms. The question arises as to what happens if the atoms are replaced by molecules elongated in one direction. The answer is to be found in that peculiar intermediate state of matter: the liquid crystal. A description of arrangements in terms of positions of centres of gravity is inadequate for elongated molecules. [ABSTRACT FROM AUTHOR]

An encyclopedia entry for phospholipids kinases is presented. Phospholipid kinases comprise a family of enzymes that phosphorylate phosphatidylinositol and phosphatidylinositides. They are preferentially phosphorylate distinct positions of the inositol ring. Despite marked differences between the various phosphoinositide-3-kinases, they all share characteristic structural features. They exhibit three conserved domains.

An encyclopedia entry for the term "lipid modifications" is presented. Other terms used for it include lipidation, S-acylation, myristoylation, prenylation, palmitoylation, isoprenylation, GPI anchors and glypiation. Covalent attachment of lipid moieties to proteins has an important function in the cellular localization and function of a proteins in all eukaryotic cells. These proteins are called lipidated proteins and are classified according to the identity of the attached lipid.

The article presents an encyclopedia entry for "intracellular transport." It comprises both the correct targeting and the mechanism of transport of newly synthesized proteins and lipids to their destination and their retrieval from organelles and the plasma membrane. A model of intracellular transport within a mammalian cell is also presented.

The article presents a study which identifies the role of adipose tissue in storing and releasing lipids for oxidation by muscles and other active tissues. It was cited that certain adipose depot have significant capacity for the synthesis and release of glutamine. Provision of glutamine to support protein synthesis in lymphoid cells may be another way in which adipose tissue supplies the immune system during periods of anorexia and cachexia.

Introduction Histological organization, cytological features as well as functional aspects confer specificity to the odontoblasts. These post-mitotic, neural crest-derived cells are most often aligned in a single layer at the periphery of the dental pulp and secrete the organic components of predentin-dentin, including collagens and non-collagenous proteins. The functional odontoblasts, with one or more cytoplasmic processes extending into the predentindentin are connected by junctional complexes which probably do not completely seal the inter-odontoblastic spaces. The dentin extracellular matrix shows great similarities to bone matrix. However Smith and Hall (1990) strongly supported the phylogenetic emergence of distinct osteogenic and dentinogenic cell lineages. Odontoblast terminal differentiation, allowing for dentinogenesis, represents the end point of a developmental sequence initiated during specification of neural crest-derived connective cell phenotypes and including patterning of the dental cells in the developing arches. Tooth class-specific histomorphogenesis leads to tooth-specific spatial distribution of functional odontoblasts (see Jernvall, 1995; Ruch, 1985, 1987, 1995a; Ruch et al., 1995 for reviews). Interestingly the analysis of the fate of uniparental mouse cells in chimeras indicated that the odontoblasts have a maternal origin (Fundele and Surani, 1994); thus genetic imprinting might affect odontogenesis. Chapter 5 of this book examines the origin and early evolution of dentine, and Chapter 6 examines pulpodentinal interactions in the development and repair of dentine. Both include discussions of the initial developmental aspects of the odontoblast cell lineage. Here we concentrate exclusively on the physiological terminal differentiation of these cells. As far as reactionary and reparative dentins are concerned see Lesot et al., 1994; Smith et al., 1995; Tziafas, 1995. [ABSTRACT FROM AUTHOR]

Cationic liposomes are preparations of positively charged lipids used for transfection of mammalian cells in vitro and in vivo. Although viruses efficiently infect mammalian cells, the potential risks of viral gene delivery spurred research in the development of synthetic chemical vectors that would duplicate viral delivery but have no risk of infectious complications. These nonviral vectors were first developed in the late 1980s. Cationic lipids are attractive vectors for vascular gene transfer studies owing to ease of preparation, reproducibility, and safety (1-3). In this chapter, we describe our experience with vascular gene transfer using four liposome reagents: DOTMA/DOPE, DC-cholesterol, DOSPA/DOPE, and DMRIE/DOPE. [ABSTRACT FROM AUTHOR]

The membranes of animal cells contain a substantial amount of lipid, which may account for between 20 and 80% of the membrane mass. The predominant lipid components are phospholipids (PL) and cholesterol; with glycolipids, cholesterol esters, glycerides, and free fatty acids as minor constituents. PL perform a basic structural role in the cell membrane. They are arranged in a bilayer configuration, in which proteins are embedded, or associated peripherally. However, PL do not merely form an inert framework in membranes, they also play important functional roles in intracellular signaling, secretion, membrane transport, endocytosis, and cell fusion. [ABSTRACT FROM AUTHOR]

Glycolipids are an important group of diverse molecules present in the plasma membrane and to a more limited extent in the intracellular membranes of the Golgi and lysosomal systems of eukaryotic cells. They are prominent as antigenic determinants and as the ligands for specific lectin binding, and there are many examples in which they have been used as cell specific markers. The cellular glycolipid pattern frequently shows changes with the state of differentiation and may be altered following viral transformation. In animal cells the most common and most varied glycolipids are glycosphingolipids, and the methods of isolation and analysis given are mainly for this class of molecule. Methods are given for the extraction of total glycolipid from small volumes of tissue and for the isolation of the glycolipids from such extracts. Methods of fractionating and quantitating the acidic and neutral glycolipids are described, which do not require the use of specialized equipment such as high-performance liquid chromatography (HPLC), gas chromatography (GC), or mass spectroscopy and which can be performed easily in the general laboratory. [ABSTRACT FROM AUTHOR]

The fatty acids (FA) of animal, plant, and microbial origin are predominantly unbranched aliphatic chains with an even number of carbon atoms and a single carboxyl group. FA can be classified as saturated, monounsaturated, or polyunsaturated (Fig. 1). Saturates have all single carbon-to-carbon bonds. Monounsaturates contain a single cis double bond, whereas polyunsaturates have two or more. A list of the commonly occurring natural FA in animal tissues is shown in Table 1. In general, FA do not exist as free carboxylic acids in living cells. In animals, they are mainly esterified into membrane phospholipids (phosphoglycerides and sphingolipids) and cytosolic neutral lipids (triglycerides and cholesteryl esters). In order to analyze the FA components of cell lipids, they must first be converted into nonpolar, volatile derivatives before they can be separated and quantified by the rapid and highly sensitive technique of gas liquid chromatography (GLC). [ABSTRACT FROM AUTHOR]

Phospholipids are amphipathic molecules of great importance and widespread in biological material. They play an essential role in the structure and function of biological membranes. They are classified according to the nature of the "backbone" residue (glycerol or sphingosine), the type of nitrogenous base (or hexahydric alcohol) attached to it, and the nature of the chemical bonds (ester or ester and ether) linking the hydrocarbon chains to the backbone molecule. Within the same class, an enormous number of subclasses is possible through variation in the number of carbon atoms in the hydrocarbon chains, their degree of unsaturation, and, in the case of the glycerophos-pholipids, the position (C1 or C2) of the particular fatty acid (or ether) residues on the glycerol backbone. High performance liquid chromatography (HPLC) has emerged as one of the most powerful and versatile forms of separation technique that can be applied to the efficient separation and determination of phospholipids. [ABSTRACT FROM AUTHOR]

A definition of the term "inositol lipids" is presented. It is short for inositol phospholipids which are also known as phosphoinositides. It is a class of phospholipids that has inositol as the headgroup. Inositol lipids have a variety of roles in different cellular processes such as being a precursor of INS(1, 4, 5)P3.