Molecular phylogenetic relationships among species of the Malagasy-Comoran gecko genus Paroedura (Squamata: Gekkonidae)

We use approximately 3100bp of mitochondrial (ND2, ND4) and nuclear (RAG1, phosducin) DNA sequence data to recover phylogenetic relationships among 14 of the 16 recognized taxa of the lizard genus Paroedura as well as two undescribed forms. These geckos are endemic to Madagascar and the Comores and are popularly kept and bred by herpetoculturalists. The closest relative of Paroedura is another Indian Ocean leaf-toed gecko, Ebenavia. Both Bayesian inference and maximum parsimony strongly support the monophyly of two major clades within Paroedura that conflict with existing species group assignments based on scale characteristics. Our well-resolved tree elucidates a biogeographic pattern in which eastern Paroedura are most basal and western and south-western species form a monophyletic group. Our data demonstrate the phylogenetic utility of phosducin, a novel marker in squamate phylogenetics, at the intrageneric level.     

Global diversity of lizards in freshwater (Reptilia: Lacertilia)

No lizards are strictly aquatic, but at least 73 species in 11 different families can be considered to regularly utilize freshwater habitats. There are no aquatic lizards in the Nearctic or Palearctic regions, whereas the Neotropics, Southeast Asia, and the Indo-Australian Archipelago support the greatest diversity of freshwater forms, particularly in the families Gymnophthalmidae, Scincidae and Varanidae. A number of larger aquatic lizards are harvested for food and for the reptile skin trade and several are CITES listed. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Targeting the alpha-folate receptor with cyclopenta[g]quinazoline-based inhibitors of thymidylate synthase

The alpha-FR has been reported to be overexpressed in many carcinomas, in particular those of the ovary and uterus. The high expression of alpha-FR in some tumours compared with normal tissues has been exploited over the last decade for folate-mediated targeting of macromolecules, anticancer drugs, imaging agents and nucleic acids to cancer cells. CB300638, a cyclopenta[g]quinazoline-based inhibitor of thymidylate synthase (TS), has been reported to have high affinity for the receptor and selectivity for alpha-FR overexpressing tumour cell lines. In this study, the structural features of the molecule, in particular modifications at the 2-position, have been investigated with respect to TS inhibition, affinity for the alpha-FR and reduced folate carrier (RFC) and activity in A431-FBP cells (transfected with human alpha-FR) compared with neo-transfected A431 cells. Compounds 1a,b, 2a,b and 3a,b were synthesised utilising multistep sequences. It was found that the 2-substituent does not affect the affinity for the alpha-FR; however, it greatly affects selectivity for A431-FBP cells, and suggests that there are factors other than TS inhibition and alpha-FR affinity that are important for the activity of these compounds. Compound 2b (2-CH2OH derivative) displayed the highest selectivity for the A431-FBP cells compared with A431 cells.     

Bifunctional plant defence enzymes with chitinase and ribosome inactivating activities from Trichosanthes kirilowii cell cultures

Three bifunctional plant enzymes (named TKC 15, TKC 28-I, and TKC 28-II) with both chitinase and RIP activity were purified from the medium of Trichosanthes kirilowii plant cell cultures. Highly purified preparations of these proteins exhibited endochitolytic activity as well as the specific 28S rRNA N-glycosidase activity characteristic of ribosome inactivating proteins (RIPs). In addition to providing a competitive advantage to the plant, these enzymes offer the possibility of improved antifungal protection when expressed in transgenic plants.     

Bioreactor studies of growth and nutrient utilization in alfalfa suspension cultures

Alfalfa (Medicago sativa L.) cells were grown in 500 ml, aerated and stirred batch bioreactors using Schenk and Hildebrant medium. For cultures in which the pH was allowed to vary, we observed two fairly distinct growth phases. Evidence is presented which indicates that the two-phase growth is most likely a result of the two nitrogen sources in the medium. The ammonium present in the medium is directly utilized during the first growth phase and ammonium resulting from intracellular nitrate reduction is utilized during the second phase. During the first growth phase, sucrose is completely hydrolyzed to glucose and fructose with some glucose and fructose consumption. In the second growth phase glucose is consumed preferentially over fructose. Attempts at maintaining the pH at 5.5 using 1N NaOH as the base titrant resulted in very little cell growth compared with cultures for which the pH was allowed to vary.