实验基础

Since the identification of HIV (human immunodeficiency virus) as the retrovirus responsible for AIDS (acquired immunodeficiency syndrome), huge efforts have been made to identify compounds possessing antiviral activity. Many assay systems are available to measure various s ...

A critical step in the life-cycle of retroviruses is the integration of the double-stranded DNA copy of their RNA genome into the genome of the host cell (1). Although the provirus DNA sequences flanking the site of integration are precisely determined and characteristic of each virus (2), the vast m ...

In order to study cell lineage in any given experimental situation, a method by which a label can be introduced into a precursor cell is required. By means of this label, the subsequent fate of the cell and its progeny can be followed. A retrovirus, as an agent of gene transfer, can be used as a genetic label, providi ...

The discovery of a filterable agent that allowed the transmission of cancers in chickens (1) was the first identification of the viruses now known as retroviruses. Subsequently, genes transmitted by some retroviruses were identified as transforming oncogenes. These findings sugge ...

The enzyme penicillin G acylase (PGA) is currently employed at an industrial scale in the hydrolysis of penicillin and cephalosporin G. Here, we describe the preparation of a new immobilized preparation of the enzyme that yields derivatives that are very thermostable and resistant in the pr ...

Materials and procedures are described for the overproduction and purification of acetate kinase from Methanosarcina thermophila. Methods are detailed for large-scale preparation of the unaltered enzyme and for overproduction and one-step purification of the histidine-t ...

Glucose dehydrogenases (GDHs) occur in several organisms such as Bacillus megaterium and Bacillus subtilis. They accept both NAD+and NADP+as cofactor and can be used for the regeneration of NADH and NADPH. In order to demonstrate their applicability we coupled an NADP+-dependent, (R)-sp ...

Phytases are hexakisphosphate phosphorylases that initiate the hydrolysis of phosphate from phytate (myo-inositol hexakisphosphate), the major form of phosphorus in plant foods and feeds. These enzymes have been increasingly used worldwide for animal nutrition, environm ...

The biotechnological potential of pectinolytic enzymes from microorganisms has drawn a great deal of attention for use as biocatalysts in a variety of industrial processes. The role of acidic pectinases in extraction and clarification of fruit juices is well established. Recently, t ...

Proteases represent one of the three largest groups of industrial enzymes and account for about 60% of the total worldwide sale of enzymes. They are degradative enzymes of central importance because they can be employed in a number of industries to create change in product taste, texture, and appe ...

Huge amounts of alkaline enzymes are used in the detergent industry, and they have been widely incorporated into heavy-duty laundry and automatic dishwashing detergents. The alkaline enzymes used in modern detergents are protease, cellulase, α-amylase, lipase, and mannanase. In this ...

Phenylalanine dehydrogenase (L-phenylalanine: NAD+oxidoreductase, deaminating , PheDH) from Bacillus sphaericus R79a, overproduced in Escherichia coli JM109/pBPDH1-DBL, is active toward 3-substituted pyruvic acids with bulky substituents in the reductive aminat ...

The expression of genes coding for heterologous extracellular enzymes or proteins in corynebacteria has provided new capacities to these industrially important microorganisms, such as the use of the culture media as sources of essential amino acids and hydrolytic enzymes that can be ...

Nondigestible oligosaccharides (NDOs), namely prebiotic oligosaccharides, are functional food ingredients that possess properties that are beneficial to the health of consumers. These include noncariogenicity, a low calorific value, and the ability to stimulate the growth ...

Enzymes control and regulate all biochemical processes in the body. In a single second, several million enzymes mediate chemical reactions occurring in a living system. Enzymes are highly specific in their function because each enzyme is programmed to carry out one special task. The immense ...

The biosensor field has grown enormously since the first demonstration of the biosensor concept by Leland C. Clark Jr. in 1962. Today’s biosensor market is dominated by glucose biosensors, mass-produced enzyme-electrodes for the rapid self-diagnosis of blood glucose levels by diabetes ...

Molluscum contagiosum virus (MCV) lesions are limited to the human epidermis and can persist for months, showing only weak signs of inflammation. Because a culture system has not yet been created to replicate MCV, this chapter describes how the virus can be isolated from patient specimens. From ...

Biochemical and functional analysis of poxvirus genomes, genes, and proteins has entered a new era with the recent sequencing of more than 30 poxvirus genomes. The management and analysis of this volume of sequence data in an efficient and effective manner requires specialized computer so ...

The vaccinia virus-based expression of viral envelope glycoprotein genes—derived from enveloped viruses that infect their respective host cells through a pH-independent mechanism of membrane fusion—has been a powerful tool in helping to characterize these important attach ...

Concern regarding the use of variola and monkeypox viruses as bioterrorist agents has led to an increased study of orthopoxviruses to understand the molecular and cellular basis of pathogenesis and develop safe and effective antivirals and vaccines against smallpox. Crucial to these ...