实验基础

For mutagenesis of BAC-cloned herpesvirus genomes, we have adapted a two-step replacement procedure originally described by O’Connor et al. (1) for the manipulation of large DNA segments in Escherichia coli (E. coli). In principle, the mutant allele to be introduced is provided on a so-called s ...

In the last few years, mutagenesis of viruses with large DNA genomes (like the herpesviruses) was simplified by cloning the viral genomes as bacterial artificial chromosomes (BACs) and their subsequent transfer into Escherichia coli (E. coli.). Owing to the high frequency of restriction s ...

Herpesviruses form a family of DNA viruses that are of considerable medical importance (1). Although the genomes of many members of the herpesviruses have been completely sequenced, our knowledge on the function of the majority of herpesvirus genes is still quite insufficient. This is espe ...

Herpesviruses have been detected in a vast variety of vertebrate species and in at least one invertebrate. It is anticipated that the approx 120 different herpesviruses known today represents only a fraction of the number that actually exists (1). Each virus is closely associated with its main ...

Transgenic mice are widely used for determination of gene function and to generate animal models of human disease (1). Such mice are generated by introducing a gene of interest into the genome and ectopically expressing it using a heterologous promoter. The choice of the heterologous promot ...

Bacterial artificial chromosomes (BACs) have become a central tool in functional genomics. This is due to their average cloning capacity (around 150 Kb), which can accommodate most eukaryotic genes along with their full set of regulatory elements, and to their greater convenience in hand ...

Recombinogenic engineering, or the modification and cloning of DNA molecules via homologous recombination, has opened up a new era. In contrast to conventional cloning strategies, recombinogenic engineering can be carried out at virtually any chosen position on a given target DNA mol ...

In the era of functional genomics, bacterial artificial chromosome (BAC) is an ideal choice of vector for cloning and manipulating large DNA fragments (1). In addition to providing a system that is able to maintain large DNA fragments (average insert size approx 150–200 kb), BAC DNA can be purified by ...

Bacterial artificial chromosomes (BAC) are F-factor plasmid based vectors that are maintained as 1 or 2 copy plasmids in their bacterial host strain. BACs have the capacity for maintaining large, often more than 300 kb fragments of mammalian DNA as stable inserts and avoid much of the insert chime ...

Large DNA (100 kb) transformation methods have been reported in tomato using Agrobacterium-mediated transformation (1) and tobacco using biolistic bombardment (2). Both methods used modified bacterial artificial chromosomes (BACs) such as BIBAC or pBACwich. BIBAC vector (used ...

Alterations in DNA copy number underlie certain developmental abnormalities and are frequent in solid tumors. Microarray-based comparative genomic hybridization (array CGH) provides a high throughput means to measure and map copy number aberrations on a genome-wide scale and to l ...

Vertebrate genomes are globally heavily methylated at the sequence CpG with the exception of short patches of GC-rich DNA, usually between 1–2 kb in size, which are free of methylation and these are known as CpG islands (see refs. 1 and 2 for reviews). In addition to distinctive DNA characteristics, CpG i ...

Positional cloning involves the genetic, physical, and transcript mapping of specific parts of a genome (1). Linkage analysis can map specific activities, or phenotypes, to a quantitative trait locus (QTL), a genomic region no smaller than 1 centiMorgan (cM) or megabase (Mb) in length. Physic ...

Genetic markers have evolved over the years, increasing in their numbers and utility. Beginning with phenotypes such as smooth or wrinkled, the selection of genetic markers broadened to include blood group and histocompatibility antigens, and protein allotypes. Around 1980, DNA itse ...

Campylobacter spp. is one of the most commonly reported bacterial causes of acute diarrheal disease in humans throughout the world (1–3). The thermophilic Campylobacter jejuni, C. coli, C. lari, and C. upsaliensis are the most important species, with C. jejuni accounting for more than 95% of all the h ...

Since 1983, when Escherichia coli O157:H7 was first recognised as a cause of hemorrhagic colitis and hemolytic uremic syndrome (HUS), verotoxin-producing strains of E. coli (VTEC) have been identified as the cause of increasing numbers of cases of serious human illness (1,2). One of a number of lar ...

The rapid detection of foodborne pathogens such as Listeria monocytogenes requires ultrasensitive techniques that give measurable responses with low numbers of the target bacteria in food samples or enrichment cultures. Although a number of approaches are possible for detecti ...

Most Escherichia coli strains are harmless commensals in the human gut, but some strains are known to cause disease. The enterohemorrhagic E. coli (EHEC) strains of serotype O157:H7 causes hemorrhagic colitis, which may develop into life-threatening hemolytic uremic syndrome. Polym ...

One of the major problems in the food industry, particulary in dairy products, is the occasional presence of the pathogen Listeria monocytogenes, which has been associated with food-borne disease outbreaks (1). The association of listeriosis with the consumption of processed foods has p ...

During the last few years we have seen a public debate, involving every social statement, concerning food products and ingredients (1). The appearance in the market of the first food products, or organisms, which have been improved by recombinant DNA technologies (rDNA), has been received by soc ...