微生物学技术

Expression of multiple genes involved in a particular metabolic pathway in a heterologous host facilitates the study of fungal secondary metabolite biosynthesis and production of useful compounds. Two plasmids with different selection markers, argB and the pyrithiamine resis ...

Plasmid vector construction is an essential step for molecular microbiology yet often a time-consuming process. Manipulation of the fungal genome to express genes to activate secondary metabolite production often requires creation of plasmid constructs in a reiterative fashi ...

Targeted gene deletions and promoter replacements are proving to be a valuable tool for awakening and analyzing silent secondary metabolism gene clusters in Aspergillus nidulans and, as molecular genetic methods for manipulating the genomes of other fungi are developed, they will li ...

Clostridium difficile is a spore-forming, toxin-producing, anaerobic bacterium abundant in soils and water. Frequent and early colonization of the human intestinal flora is common and often asymptomatic. Antimicrobials given commonly disrupt the intestinal microflora and t ...

Never before has there been a more timely opportunity to investigate the molecular genetics of Clostridium difficile. Over the last few years the perception of C. difficile has changed from an obscure, and often under-researched, bacterium to one of major clinical importance, at least in indu ...

Clostridium difficile infection (CDI) occurs as a disease with a spectrum of severity ranging from mild, self-limiting diarrhoea to a severe colitis, pseudomembraneous colitis or toxic megacolon. The disease arises as a major complication of antibiotic therapy and is most commonly ac ...

Clostridium difficile is a pathogen on the move, as evidenced by the rapid transcontinental spread of the so-called hypervirulent 027 strains, followed by the emergence of further PCR ribotypes such as 017, 078 and 106. This provides a rare opportunity to study the evolution of virulence in acti ...

Clostridium difficile is a gram-positive, spore-forming, toxin-producing anaerobic bacillus that is being increasingly implicated as the leading cause of diarrhea and colitis, particularly in hospitalized, elderly patients. Studies to date suggest that C. difficile toxins A a ...

The bacterial cell surface is an important structure as it mediates interactions with the external environment. In the case of pathogens like Clostridium difficile, the cell wall and its components also have to mediate interactions with the host cells and their products. In this chapter we di ...

Toxin A (TcdA) and Toxin B (TcdB) are the major virulence factors that contribute to the pathogenesis of Clostridium difficile-associated diarrhoea (CDAD). These enterotoxins act by glucosylation of members of the Rho protein family of small GTP-binding proteins. This leads to the disor ...

Multilocus sequence typing (MLST), a nucleotide sequence-based characterization of allelic polymorphism of housekeeping genes, has been proposed as a new approach for population and evolutionary genetics and global epidemiology of bacterial pathogens. MLST provides unam ...

Clostridium difficile shows considerable variability in the PaLoc region encoding two main virulence factors, toxins TcdA and TcdB. Strains with changes in PaLoc are defined as variant toxinotypes and currently 27 such groups are recognized (I to XXVII). Toxinotype 0 includes strains w ...

Molecular typing methods for Clostridium difficile are based on gel electrophoresis of restriction fragments (endonuclease restriction analysis, REA; pulsed field gel electrophoresis PFGE; toxinotyping), PCR amplification (PCR ribotyping, arbitrarily primed PCR, mu ...

Mouse models have been developed to study the pathogenic process of Clostridium difficile infections, first the intestinal colonization and second the toxin production. These models have also been used to test the role of environmental conditions that modulate infection. Differe ...

The Golden Syrian hamster is widely regarded as the most relevant small animal model of Clostridium difficile disease as oral infection of animals pre-treated with antibiotics reproduces many of the symptoms observed in man. These include diarrhoea, histological damage, colonisat ...

Genetic manipulation of Clostridium difficile is notoriously difficult, currently there is only one reliable method for generating random mutations in the organism and that is to use the conjugative transposon Tn916. Tn916 enters the genome of most strains of C. difficile with no obvious ...

Clostridium difficile is the causative agent of a range of intestinal diseases, collectively referred to as Clostridium difficile-associated disease (CDAD). The recent emergence of “hypervirulent” strains associated with increased rates of mortality and severity of disease ...

Members of the genus Clostridium have long been recognised as important to humankind and its animals, both in terms of the diseases they cause and the useful biological processes they undertake. This has led to increasing efforts directed at deriving greater information on their basic biolo ...

The use of shRNA for knockdown of gene expression is a powerful method. In addition to transient transfection of RNA oligonucleotides, various DNA-based vectors that express short hairpin RNAs have been successfully used for efficient depletion of gene products. Replication-defec ...

The adenovirus major late transcription unit (MLTU) encodes the main structural capsid proteins. Expression from the MLTU is accomplished through alternative mRNA processing and use of a terminal exon coding strategy. The capsid proteins hexon, penton, and fiber contribute to effic ...