实验基础

Human rotaviruses are considered the main cause of viral gastroenteritis in infants and young children throughout the world (1). Their transmission is through the fecaloral route, mostly after ingestion of contaminated water and food (2). Since an extremely high number of virus particl ...

Salmonella enterica is widely recognized as a major cause of foodborne diseases in humans and animals and has been isolated from environmental sources in increasing numbers worldwide (1,2). Conventional typing methods such as serotyping and phage typing have been and still are the mains ...

Thermophilic Campylobacter spp., mainly Campylobacter jejuni and to a lesser extent C. coli are recognized as the most common bacteriological causes of gastroenteritis in humans (1). As enteric infection with Campylobacter organisms cannot be distinguished from that caused by oth ...

Antimicrobial resistance determinants may be transferred among bacteria via mobile genetic elements including plasmids, transposons, and the more recently explored integrons (1). Integrons are naturally occurring genetic elements found as part of the Tn21 transposon family ...

Particle bombardment is a physical method of cell transformation that can be applied in vitro as well as in vivo (1,2). The DNA- or RNA-coated gold particles that are generally used are of high density, subcellular in size, and are accelerated to high velocity to carry the genetic information into cells. ...

The Herpesviruses family consists of over 100 distinct viruses that are responsible for a variety of important human and veterinary diseases. These viruses are subclassified into alpha-, beta-, or gamma- herpesviruses, dependent upon a variety of criteria. Eight herpesviruses are hum ...

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 ...

Viruses are parasites that are strictly dependent on the host cell for replication. In general, the more complex a virus, the more complicated the network of interactions between the virus and the host. Many of these interactions are still unrevealed or not understood in detail. The generation of ...

Transgenic mice provide an important experimental system for studying the effects of gene overexpression and for analyzing the expression of well-characterized “single” genes that contribute to a particular trait. However, single-gene expression in transgenic (Tg) mice is not ap ...

Microinjection of DNA into the pronuclei of fertilized oocytes is one of the two most commonly used methods for gene transfer into the mouse genome (1,2). The first successful attempt to perform this technique was carried out by Lin in 1966 (3), who could show that the early fertilized embryo could surv ...

Many functional studies require the transfection of bacterial artificial chromosome (BAC) clones into mammalian cells. Because most BAC vectors do not have a mammalian selection marker or do not have one suitable for all cell types, it is usually necessary to modify BAC clones to include a sele ...

While much is known about the structure of the nucleosome, how a chain of contiguous nucleosomes rearranges to form a fiber is much less understood. Microscopical techniques with nucleosomal resolution (electron microscopy and the newly emerging probe microscopies) have been useful ...

In the nucleus of eukaryotic cells, DNA is packaged into a nucleoprotein complex known as chromatin (1). This complex provides the compaction and structural organization of the DNA for processes such as replication, transcription, recombination, and repair. The highly compact struct ...

The majority of DNA in eukaryotic cells is packaged by histones and many poorly characterized nonhistone proteins to form a dynamic structure known as chromatin. Chromatin is a periodic structure made up of repeating, regularly spaced subunits, the nucleosomes. Elegant genetic experi ...

Specific acetylation at conserved lysines in the N-terminal tails of histones have been correlated with distinct chromatin structures, association of specific chromatin proteins, accessibility of nucleosomal DNA toward interaction of transcription factors, and unfolded ...

The value of a solid support was recognized early in history by the ancient Greek engineer Archimedes who, amazed by the power of the leverage machines that he invented, exclaimed that he could even move the entire planet had he only a suitable solid support to rely on. In biochemistry, sophisticated mu ...

Cell division in eukaryotes follows an extremely complex plan according to which chromosomes are first duplicated and condensed more than 10,000 times to form the mitotic chromosomes, which are finally separated by the cellular machinery into two new nuclei. Although the fascinating p ...

The packaging of DNA into a chromatin structure within the eukaryotic nucleus can affect processes such as DNA replication, transcription, recombination and repair. During nucleotide excision repair (NER), a major DNA repair pathway, rearrangements of the nucleosomal organisat ...

Folding of DNA into nucleosomes and higher order chromatin structures restricts its accessibility to proteins and drugs. Hence, the location of histone octamers on the DNA sequence (nucleosome positions) as well as structural and dynamic properties of nucleosomes may play important ...