Paleontology of leaf beetles

`The rate of evolution in any large group is not uniform; there are periods of relatise stability, and periods of comparatively rapid change.' Cockerell and LeVeque, 1931 To Yenli Ych, my beloved wife, a most wonderful person! The fossil record of the Chrysomelidae can be tentatively traced back to the late Paleozoic to early Mesozoic Triassic. Mesozoic records at least 9 subfamilies, 19 genera, and 35 species, are represented by the Sagrinae, the exclusively Mesozoic Proto scelinae, Clytrinae, Cryptocephalinae, Eumolpinae, Chrysomelinae. Galerucinac, Alticinae, and Cassidinae. Cenozoic records at least 12 subfamilies- 63 % of the extant- 12! genera, and 325 species, include the same extant subfamilies as well as the Donaciinae, Zeugophorinae, Criocerinae, and Hispinae and can be frequently identified to genus, especially if preserved in amber. Quaternary records are often identified to extant species. tn total, at least t3! genera about 4 % of total extant, and 357 species < 1 % have been reported. At least, 24 genera <1 % of the extant seem to be extinct. Although reliable biological information associated with the fossil chrysomelids is very scarce, it seems that most of the modern host-plant associations were established, at least, in the late Mesozoic to early Cenozoic. As a whole, stasis seems to be the general rule of the chrysomelid fossil record. Together with other faunal elements, chrysomelids, especially donaciines, have been used as biogeographic and paleoclimatological indicators in the Holocene. I

Cloning, Expression, and Characterization of a Neuraminidase Gene from Arcanobacterium pyogenes

Arcanobacterium pyogenes is an opportunistic pathogen, associated with suppurative infections in domestic animals. In addition to pyolysin, a pore-forming, cholesterol-binding toxin, A. pyogenes expresses a number of putative virulence factors, including several proteases and neuraminidase activity. A 3,009-bp gene, nanH, was cloned and sequenced and conferred neuraminidase activity on an Escherichia coli host strain. The predicted 107-kDa NanH protein displayed similarity to a number of bacterial neuraminidases and contained the RIP/RLP motif and five copies of the Asp box motif found in all bacterial neuraminidases. Recombinant His-tagged NanH was found to have pH and temperature optima of 5.5 to 6.0 and 55°C, respectively. Insertional deletion of the nanH gene resulted in the reduction, but not absence, of neuraminidase activity, indicating the presence of a second neuraminidase gene in A. pyogenes. NanH was localized to the A. pyogenes cell wall. A. pyogenes adhered to HeLa, CHO, and MDBK cells in a washing-resistant manner. However, the nanH mutant was not defective for adherence to epithelial cells. The role of NanH in host epithelial cell adherence may be masked by the presence of a second neuraminidase in A. pyogenes