In this study, we determined the sequences of four intimin variant genes detected in attaching and effacing Escherichia coli isolates of human origin. Three of them were novel and were designated eae-(eta), eae-(iota), and eae-(kappa). The fourth was identical to the recently described eae-(zeta), isolated from a bovine E. coli O84:NM isolate. We compared these sequences with those of published intimin-␣, intimin-␤, intimin-␥1, intimin-␥2, intimin-, and intimin-alleles. Sequence analysis of these 10 intimin alleles confirmed extensive genetic diversity within the intimin gene family in E. coli. The genetic diversity was more prominent in the 3 region (starting at bp 2112), which encodes the binding domain of intimin. Phylogenetic analyses revealed four groups of closely related intimin genes: ␣ and ; ␤ and ; ␥1 and ␥2/; and and . Calculation of homoplasy ratios of sequences of the 5 region of eae (positions 1 to 2111) revealed evidence for intragenic recombination. Split decomposition analysis also indicates that recombination events have played a role in the evolutionary history of eae. In conclusion, we recommend an eae nomenclature system based on the Greek alphabet and provide an updated PCR scheme for amplification and typing of E. coli eae.

Differences of both amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) polymorphisms were compared between the 60-d-old rice (Oryza sativa L. cv. DH7) and F3 rice plants (SP3) derived from seed, which endured a 7-d-space flight in March 2002. Total leaf AFLP DNA bands amplified from 22 primer pairs were 537 in DH7, whereas 562 in SP3. From the total 267 SSR DNA bands generated by 267 primer pairs, 39 were polymorphic with 22 larger (56 %) or 17 smaller (44 %) fragment size bands. The greatest numbers of AFLP DNA bands were amplified by primer E1M1 in DH7 (33) and E3M1 in SP3 (35), whilst the least by E4M3 in DH7 (14) and E5M2 in SP3 (16).