Cretaceous and Eocene fossils of the rare extant genus Synneuron Lundstrom (Diptera: Canthyloscledidae): evidence of a true Pangean clade.

The first two fossil species of the canthyloscelid genus Synneuron are described based on compression wings. Synneuron eomontana sp. nov. is described from the Middle Eocene Coal Creek Member of the Kishenehn Formation, in the USA, and Synneuron jelli sp. nov. is described from the Lower Cretaceous Koonwarra Fossil Bed of the Korumburra Group, in Australia. The wings are illustrated and compared to the extant species of the genus, to species of the three other recent genera of Canthyloscelidae and to an anisopodid. A phylogenetic analysis of the relationships between the species of Synneuron was performed. The Eocene fossil S. eomontana appears as sister of the pair of recent Holarctic species of the genus, while the Australian Cretaceous species S. jelli is sister of the clade with the species of Synneuron of the northern hemisphere. The sister group of Synneuron is the canthyloscelid clade (Hyperoscelis + Canthyloscelis), for which a middle Jurassic fossil is known. At the early Cretaceous, Gondwana was already separated from Laurasia and the disjunction between the species of Synneuron in Australia and the northern hemisphere clade of the genus suggest a true pangeic origin for the genus. The biology of the canthyloscelid larvae is shaped by its trophic specialization-xylosaprophagous. This suggests that the transition from the Pangean Jurassic gymnosperm-dominated forests to the late Cretaceous angiosperm-dominated forests may be related to the low recent diversity of Synneuron or of the canthyloscelids in the world-and maybe to the extinction of the genus in the southern hemisphere. This major turnover of the vegetation type along the Cretaceous may be also somehow related to the complete extinction of other groups of flies strictly associated with gymnosperms, as may be the case of the lower brachyceran family Zhangsolvidae. This speculation needs additional corroboration from other groups, that will become available with the combination of systematics, paleontology and biogeographical information of different early Cretaceous clades.

Hemoglobin-derived porphyrins preserved in a Middle Eocene blood-engorged mosquito.

Although hematophagy is found in ~14,000 species of extant insects, the fossil record of blood-feeding insects is extremely poor and largely confined to specimens identified as hematophagic based on their taxonomic affinities with extant hematophagic insects; direct evidence of hematophagy is limited to four insect fossils in which trypanosomes and the malarial protozoan Plasmodium have been found. Here, we describe a blood-engorged mosquito from the Middle Eocene Kishenehn Formation in Montana. This unique specimen provided the opportunity to ask whether or not hemoglobin, or biomolecules derived from hemoglobin, were preserved in the fossilized blood meal. The abdomen of the fossil mosquito was shown to contain very high levels of iron, and mass spectrometry data provided a convincing identification of porphyrin molecules derived from the oxygen-carrying heme moiety of hemoglobin. These data confirm the existence of taphonomic conditions conducive to the preservation of biomolecules through deep time and support previous reports of the existence of heme-derived porphyrins in terrestrial fossils.

Kishenehna prima, a new genus and species of darner dragonfly (Odonata, Aeshnidae, Gomphaeschninae) from the early middle Eocene Kishenehn Formation of Montana, USA.

We describe the darner dragonfly Kishenehna prima n. gen. and sp. (Odonata, Aeshnidae, Gomphaeschninae) based on a well-preserved, nearly complete female hind wing from the Lutetian Coal Creek Member of the Kishenehn Formation, northwestern Montana, USA. Kishenehna is morphologically close to the late Paleocene genus Alloaeschna Wighton Wilson of Alberta, Canada. This is the first dragonfly (Anisoptera) described from the Kishenehn Formation and the first from the Lutetian of the Western Hemisphere.

Review of the fossil record of Bolitophilidae, with description of new taxa and discussion of position of Mangas Kovalev (Diptera: Sciaroidea).

The dipteran family Bolitophilidae, with the single extant genus Bolitophila, is a small family of mycophagous flies. In marked contrast to related families such as Sciaridae and Mycetophilidae, the family has a poor fossil record with no definite species assigned to the genus. In addition, the position of the extinct Cretaceous subfamily Mangasinae Kovalev, 1986 (described in Bolitophillidae) has been controversial and it has been suggested that species in this clade may belong to other sciaroid families. This situation is made worse by misplacement of the type specimen. We herein describe two new species of Bolitophila, Bolitophila warreni sp. nov. from the 46-million-year-old Kishenehn Formation in Montana, USA and Bolitophila rohdendorfi sp. nov. from Baltic amber. Bolitophila pulveris Lewis, 1969 is reassigned to Sciaroidea incertae sedis. The subfamily Mangasinae is reviewed and its position within the Bolitophilidae confirmed. Two new species of Mangas, M. kovalevi sp. nov. and M. brevisubcosta sp. nov., both from the Lower Cretaceous of Khasurty in Western Transbaikalia, are described.

Differentiating primary human cells in rapid-throughput discovery applications.

Primary cultures of human cells provide an increasingly important alternative to using virally transformed or otherwise immortalized cell lines or to using cloned cell lines derived from human or animal tumors. Advances in primary cell culture techniques, media formulations, and other reagents have enabled routine culture of primary cells derived from human tissues for biomedical research and drug discovery approaches such as high content screening. That primary cells retain the phenotypic characteristics of the original tissue is one main advantage over immortalized cell lines. However, securing reliable supplies of primary cells on a large scale has been problematic. Here, two primary differentiating cell types, preadipocytes and preosteoclasts, are described to illustrate the utility of commercially produced cell systems in discovery research and rapid-throughput applications.

Tenofovir exhibits low cytotoxicity in various human cell types: comparison with other nucleoside reverse transcriptase inhibitors.

Clinical studies with tenofovir disoproxil fumarate, an oral prodrug of the nucleotide analog tenofovir, recently approved for the treatment of HIV, have demonstrated antiviral activity and good tolerability in HIV-infected patients. In order to better understand the cytotoxicity profile of tenofovir relative to the other nucleoside reverse transcriptase inhibitors (NRTIs), the in vitro effects of these agents were evaluated in various human cell types. Tenofovir inhibited the proliferation of liver-derived HepG2 cells and normal skeletal muscle cells with CC(50) values of 398 and 870 microM, respectively. In comparison, ZDV, ddC, ddI, d4T, and abacavir all showed lower CC(50) values in these two cell types. Evaluation of hematopoietic toxicity revealed that tenofovir was less cytotoxic towards erythroid progenitor cells (CC(50)>200 microM) than ZDV, d4T, and ddC (CC(50)=0.06-5 microM). Despite some degree of donor-to-donor variability, the inhibitory activity of the tested NRTIs against myeloid cell lineage, in the order of decreasing severity, was consistently ddC>ZDV>d4T>tenofovir>3TC. Finally, tenofovir showed substantially weaker effects on proliferation and viability of renal proximal tubule epithelial cells than cidofovir, a related nucleotide analog with the potential to induce renal tubular dysfunction. In conclusion, tenofovir exhibited weak cytotoxic effects in all cell types tested with less in vitro cytotoxicity than the majority of NRTIs currently used for the treatment of HIV disease.

A re-description of the fossil damselfly Eolestes syntheticus Cockerell, 1940 (Odonata: Zygoptera: Eolestidae n. fam.) with description of new taxa from the Eocene of North America.

The enigmatic species Eolestes syntheticus Cockerell, 1940, from the Early Eocene of North America, previously attributed to the lestoid family Synlestidae, is re-examined in light of the discovery of new material from the Middle Eocene Kishenehn Formation in northwestern Montana. E. syntheticus and a new species, Eolestes ramosus sp. n., are attributed to a new family Eolestidae fam. n.. In addition, a new genus and species very closely related to Lestidae but assigned to family unknown, Lutetialestes uniformis sp. n., is described from the Kishenehn Formation.