Hilary Richards

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Mercury-resistant bacteria isolated from the oral cavities of children carried one of two types of merA gene that appear to have evolved from a common ancestor. Streptococcus oralis, Streptococcus mitis and a few other species had merA genes that were very similar to merA of Bacillus cereus strain RC607. Unlike the B. cereus RC607 merA gene, however, the(More)
The indigenous plasmid pIJ101 is the parent of many cloning vectors used in Streptomyces. One early pIJ101 derivative, pIJ702, has been particularly widely used. pIJ702 lacks sti:cop/korB and accumulates single-stranded DNA (ssDNA). The 1.2 kb BclI-BclI sti:cop/korB and 0.7 kb SpeI-BclI sti regions were isolated from pIJ101 and cloned into pIJ702 at the(More)
Salmonella typhi in the bowel of a patient with enteric fever treated with chloramphenicol and later co-trimoxazole acquired resistance to these drugs. Chloramphenicol and sulphonamide resistances were determined by one plasmid, of IncH, whose carriage also changed the Vi phage type. Trimethoprim resistance was determined by a transposon, Tn7, carried in(More)
Acanthamoeba trophozoites attach to and effect amoeboid locomotion at the water-air interface of ponds. Their locomotory rate (approximately 0.8 microm s(-1)) and manner of independent movement at this interface is similar to that over solid substrata. Adhesion forces developed between amoebae and the water-air interface are greater than gravity and thus(More)
It has been shown that the mercury in dental amalgam and other environmental sources can select for mercury resistant bacteria and that this can lead to an increase in resistance to antibiotics. To understand more about this linkage we have investigated the genetic basis for mercury and antibiotic resistance in a variety of oral bacteria. In this study we(More)