Probiotic products are marketed widely throughout the world. This is especially true of yogurts that contain strains of lactic-acid bacteria of intestinal origin. Consumption of these products is aimed at promoting the wellbeing of the consumer by impacting on the collection of microorganisms that normally inhabit the intestinal tract. The development of scientifically valid probiotics requires more detailed knowledge of this intestinal microflora than is currently available. Probiotic products are marketed widely throughout the world. This is especially true of yogurts that contain strains of lactic-acid bacteria of intestinal origin. Consumption of these products is aimed at promoting the wellbeing of the consumer by impacting on the collection of microorganisms that normally inhabit the intestinal tract. The development of scientifically valid probiotics requires more detailed knowledge of this intestinal microflora than is currently available.
It is an article of faith among biochemists and molecular biologists that precious enzymes must be stored on ice. The usual reason given is that, at temperatures around freezing, enzyme activity is minimized and protein stability maximized. There is considerable evidence supporting this, but is it true for all enzymes? What about enzymes from organisms that spend part or all of their lives at temperatures around freezing? How do they manage to maintain normal enzymatic function at low temperatures? Can we learn something from cold-adapted proteins that would allow us better to understand how proteins function?
Crystalline cell surface layers (S-layers) composed of planar assemblies of protein or glycoprotein subunits are one of the most commonly observed cell envelope structures of bacteria and archaea. Isolated S-layer subunits of numerous organisms are able to assemble into monomolecular arrays either in suspension, at liquid-surface interfaces, including lipid films, on liposomes and on solid supports. Pores in S-layers are of regular size and morphology, and functional groups on the protein lattices are aligned in well-defined positions and orientations. These characteristic features of S-layers have led to various applications in biotechnology, vaccine development, diagnostics, biomimetics and molecular nanotechnology.
Baeyer-Villiger monooxygenases (BVMOs) are enzymes able to perform highly regio- plus stereoselective nucleophilic and electrophilic biooxygenations on various substrates. The resultant chiral products (lactones and sulfoxides) can be valuable for the chemoenzymatic synthesis of a wide range of useful compounds. Recent studies have provided a number of alternative active-site models that attempt to explain the exquisite and unusual selectivity of BVMOs. This article reviews some of the established applications, and considers the merits of the various predictive models.
G-protein-coupled receptors are an important class of therapeutic drug targets by virtue of their roles in the regulation of diverse cellular functions. Recent advances in the expression of heterologous G-protein-coupled receptors in the yeast have led to the development of sensitive and selective assays of their ligand-induced activation. Implementation of this new technology in the high-throughput screening of compound libraries has enabled the discovery of novel ligands for the G-protein-coupled somatostatin receptor. This article describes the broad applicability of the technology and its use in drug discovery.
Peptide nucleic acids (PNAs) are DNA analogs containing neutral amide backbone linkages. PNAs are stable to degradation by enzymes and hybridize to complementary sequences with higher affinity than analogous DNA oligomers. PNA synthesis employs protocols derived from solid-phase peptide synthesis, making the methodology straightforward and flexible. PNAs are being incorporated into an expanding set of applications, including genome mapping, the identification of mutations and measurement of telomere length. The growth in the popularity of PNAs as a tool for nucleic acid recognition should accelerate as the properties of PNAs become more familiar.
State-of-the-art techniques such as liquid-chromatography-electrospray-ionisation tandem mass spectrometry have, in conjunction with database-searching computer algorithms, revolutionised the analysis of biochemical species from complex biological mixtures. With these techniques, it is now possible to perform high-throughput protein identification at picomolar to subpicomolar levels from protein mixtures. This article provides an overview of the techniques and methodologies available for the structural elucidation and identification of proteins and peptides from complex biological samples.
Significant amounts of marine macroalgal (seaweed) polysaccharides are used in food, pharmaceuticals and other products for human consumption. Thus, the global seaweed polysaccharide industry operates in a highly regulated environment. Genetic manipulation of macroalgae to alter composition or growth characteristics may lead to products that do not fall within the current regulations: research that is readily translatable to industrial application is generally restricted to seaweed cultivation and processing and new applications of the approved polysaccharides. There is a great need, however, for research into the genome structure and metabolic pathways of commercially important marine macroalgae. This precompetitive research may not be immediately applicable to the seaweed polysaccharide industry but is critical for sustaining future commercial growth.
Probiotic products are marketed widely throughout the world, This is especially true of yogurts that contain strains of lactic-acid bacteria of intestinal origin, Consumption of these products is aimed at promoting the wellbeing of the consumer by impacting on the collection of microorganisms that normally inhabit the intestinal tract. The development of scientifically valid probiotics requires more detailed knowledge of this intestinal microflora than is currently available.
Cells in megahertz-frequency noncavitating ultrasonic standing waves concentrate at submillimetre distances and are, as large clumps, easiy removed from suspension in flow or batch systems. An ultrasonic filter for perfusion hybridoma culture is now available. Results from small-volume prototype analytical-scale systems can inform the design of effective filter or batch-clarification systems for a wide range of cell sizes, concentrations and sample volumes. Large increases in the rates of aqueous biphasic separations and of the rates and senstivities of analytical immunocoated particle-agglutination assays occur in standing waves. Ultrasonic manipulation is briefly compared with immunomagnetic and dielectrophoretic separations.
The food industry needs suitable analytical methods for process and quality control; that is, methods that are rapid, reliable, specific and cost-effective in their provision of information about physical and chemical characteristics of food. Apart from a few important analytes, such as sugars, alcohols, amino acids, flavours and sweeteners, food applications mainly focus on the determination of contaminants. However, very few biosensors play a prominent role in food processing or quality control. Considerable effort must be made to develop biosensors that are inexpensive, reliable, and robust enough to operate under realistic conditions.
Biomass is one of the most important variables in submerged-cultivation processes and, in recent years, many different sensors have been introduced for on-line or monitoring of this variable. This article provides an overview of the principles behind these sensors and discusses their application in both laboratory and industrial processes.
Definitions of ‘marine biotechnology’ often refer to the vast potential of the oceans to lead to new cures for human and animal disease; the exploitation of natural drugs has always been the most basic form of biotechnology. Although only initiated in the late 1970s, natural drug discovery from the world's oceans has been accelerated by the chemical uniqueness of marine organisms and by the need to develop drugs for contemporary, difficult to cure, diseases. Current research activities, while primarily within the academic laboratories, have generated convincing evidence that marine drug discovery has an exceedingly bright future.
Macrophages play an important role in host defense reactions, for example, by phagocytosis of particulate materials. This process also results in the rapid removal of targeting devices such as liposomes and adenovirus vectors and of nonautologous grafted cells and materials. Another aspect of macrophage function is their production and secretion of proinflammatory cytokines. Transient and organspecific suppression of macrophage function by liposome-mediated manipulation has been shown to improve the efficacy of drug and gene targeting and to reduce the symptoms of inflammatory reactions.
Biosensors utilize biological components to provide selectivity for monitoring compounds of environmental, clinical and industrial importance. A number of biosensors based on bacteria have recently been developed for monitoring toxic metals in the environment. The advantages and disadvantages of these types of biosensors are discussed.
The surface plasmon resonance technique allows direct, real-time kinetic measurements of the interaction of unlabelled biological molecules at surfaces. After a brief discussion of the principles of surface plasmon resonance, we review its application to the nonspecific adsorption of protein, the formation of phospholipid bilayers, membrane-protein interactions and DNA hybridization. The morphological studies of the biological surfaces using surface plasmon resonance microscopy and the potential of the surface plasmon resonance to measure the dynamics of surface layer heterogeneity are discussed.
After ten years of development, genetically engineered crops expressing genes from encoding insecticidal proteins are commercially available. crops, for example potatoes, cotton and corn, demonstrate high levels of protection from feeding damage by major insect pests, leading to a reduction in insecticide usage (e.g. cotton) or a yield increase (e.g. corn). Integrating crops into traditional farming systems and preserving their performance by delaying resistance development in insect populations are the main challenges to be overcome.
Plants are one of several novel hosts that can be used for the production of recombinant biopharmaceuticals such as cytokines, hormones, monoclonal antibodies, enzymes and vaccines. The novelty of this technology and its wide range of potential applications require an assessment of possible regulatory concerns in the clinical development of plant-derived biopharmaceuticals. General principles extrapolated from experience gained with biotechnology products from other sources can serve as a foundation to develop scientifically sound strategies for the large-scale production and clinical development of safe and effective biopharmaceuticals in plant hosts.
Biopolymers from marine prokaryotes, both Bacteria and Archaea, offer a number of novel material properties and commercial opportunities. The characteristics of marine exopolysaccharides and melanins that enhance the survival ability of the organisms producing them can be exploited for a number of products ranging from emulsifiers to adhesives. In the prokaryotes, the polyhydroxyalkanoates form carbon-storage molecules, but their technological application is entirely different, serving as a potential base material for biodegradable plastics. Marine biopolymers are a significant and undeveloped biological resource.
The commercial production of human proteins in recombinant microorganisms for therapeutic use is well established. Systems have been developed to exploit the natural ability of certain bacteria to secrete properly folded, bioactive proteins into the extracellular medium. The streptomycetes are a relatively well-characterized group of nonpathogenic filamentous bacteria that have the capacity to secrete large amounts of protein. In particular, lividans has the ability to secrete human proteins at a commercially viable level, thanks to relatively wellestablished plasmid-based expression systems, a high-biomass fermentation process and a low level of endogenous protease activity.