微生物学技术

Vectors containing elements of the Epstein-Barr virus (EBV) genome are primarily used to maintain cloned DNA inserts as plasmids in mammalian cells. In addition, EBV-based vectors are proving to be valuable tools in elucidating details of EBV biology that have long eluded students of the vir ...

In order to use herpes simplex virus (HSV) as a vector for the transmission and expression of foreign genes, it is obviously necessary to be able to prepare stocks of the virus and to propagate both HSV and the recombinant viruses derived from it. Similarly, the introduction of foreign genes into the virus ...

Herpes simplex viruses types 1 and 2 (HSV-1 and HSV-2) are doublestranded DNA viruses with a genome size of 152 kbp. The genome consists of two unique regions, UL (long) and Us (short), flanked by repeated sequences (Fig. 1; for review, see ref. 1). The two viruses are closely related, and both infect humans, produ ...

Most of the time, retrovirus vectors retain only cis-acting sequences from the original viral genome. These sequences allow the recombinant structure to be transcribed (LTR promoter/enhancer) and the RNA to be processed (splicing and polyadenylation signals), packaged into a virion ...

Human papillomavirus (HPV) research dates back to the turn of the century, when Ciuffo demonstrated that human warts are caused by an infectious agent, only later identified as a virus (1). More recently, the HPVs have generated particular interest, since they include some of the few viruses clea ...

COS-1 cells were created by transforming an established line of monkey epithelial cells, CV-1, with a defective mutant of SV40 (1). The SV40 mutant used carried a small deletion within the origin of replication and, although this construct transformed CV-1 cells, which are permissive for lytic g ...

On account of their relatively small, defined genomes, viruses have long been a convenient model system in which to study eucaryotic gene expression. Usually, viral infection is followed by early gene expression, which allows the subsequent processes of viral DNA replication and late gene ...

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 ...