Reappraisal of early Miocene rails (Aves,Rallidae) from central France: diversity and character evolution

In Europe, Miocene rails (Aves, Rallidae) are quite abundant, but their phylogenetic placement in the context of recent forms has remained elusive. Rails from the early Miocene of the Saint‐Gérand‐le‐Puy area in central France were first described in the 19th century, and currently, only two species are recognized, namely Palaeoaramides christyi and Paraortygometra porzanoides. Our examination of the material however suggests the presence of four, likely coeval, species of rail from these deposits. Palaeoaramides eximius, previously synonymized with Palaeoaramides christyi, is here shown to probably be a distinct species, and a previously unrecognized rail, Baselrallus intermedius gen. et sp. nov., is described. To find out how these fossil rails are related to modern Rallidae, we compared them with an extensive sample of extant rails and identified plesiomorphic and derived features for crown group Rallidae. Our assessment does not support a particularly close relationship of either Palaeoaramides to Aramides or Paraortygometra to Crex (Ortygometra), and overall, these fossil rails are more primitive than previously assumed. Based on our observations of the morphology of the previously undescribed humerus of Palaeoaramides, we show this taxon to be outside crown group Rallidae, and perhaps closely related to the early Oligocene taxon Belgirallus. On the other hand, Paraortygometra porzanoides bears a resemblance to recent flufftails (Sarothrura spp.) in some elements, but whether it can be included in a clade together with flufftails is uncertain.     

Photopigments underlying color vision in ringtail lemurs (Lemur catta) and brown lemurs (Eulemur fulvus)

A recent examination of color vision in the ringtail lemur produced evidence that these prosimians could make color discriminations consistent with a diagnosis of trichromatic color vision. However, it was unclear if this behavior reflected the presence of three classes of cone or whether lemurs might be able to utilize signals from rods in conjunction with those from only two classes of cone. To resolve that issue, spectral sensitivity functions were obtained from ringtail lemurs (Lemur catta) and brown lemurs (Eulemur fulvus) using a noninvasive electrophysiological procedure, electroretinographic flicker photometry. Results from experiments involving chromatic adaptation indicate that these lemurs routinely have only a single class of cone photopigment in the middle to long wavelengths (peak sensitivity of about 545 nm); they also have a short-wavelengthsensitive cone pigment with peak of about 437 nm. The earlier behavioral results are suggested to have resulted from the ability of lemurs to jointly utilize signals from rods and cones. The cone pigment complements of these lemurs differ distinctly from those seen among the anthropoids. © 1993 Wiley-Liss, Inc.     

A novel probe for phosphatidylinositol 4-phosphate reveals multiple pools beyond the Golgi

Polyphosphoinositides are an important class of lipid that recruit specific effector proteins to organelle membranes. One member, phosphatidylinositol 4-phosphate (PtdIns4P) has been localized to Golgi membranes based on the distribution of lipid binding modules from PtdIns4P effector proteins. However, these probes may be biased by additional interactions with other Golgi-specific determinants. In this paper, we derive a new PtdIns4P biosensor using the PtdIns4P binding of SidM (P4M) domain of the secreted effector protein SidM from the bacterial pathogen Legionella pneumophila. PtdIns4P was necessary and sufficient for localization of P4M, which revealed pools of the lipid associated not only with the Golgi but also with the plasma membrane and Rab7-positive late endosomes/lysosomes. PtdIns4P distribution was determined by the localization and activities of both its anabolic and catabolic enzymes. Therefore, P4M reports a wider cellular distribution of PtdIns4P than previous probes and therefore will be valuable for dissecting the biological functions of PtdIns4P in its assorted membrane compartments.     

Osteogenesis imperfecta: a heterogeneous morphologic phenotype in cultured dermal fibroblasts

Summary Osteogenesis imperfecta (OI) is a phenotype with clinical and biochemical heterogeneity. We report here that expression of the OI phenotype extends to the level of dermal fibroblast morphology in vitro. Growth characteristics and morphology of control (n=6) and OI cell strains (n=10, representing the four major OI categories, Sillence classification) were compared by measuring the following: (i) days required in culture to reach confluence after plating at uniform density; (ii) cell density at confluence; (iii) width and length of cells (measured on phase contrast micrographs at 300xmagnification). Our results show that: (i) OI fibroblasts take longer (11–27 days, mean 20 days) than control cells (10–19 days, mean 16 days) to reach stationary phase; (ii) all OI phenotypes achieve a lower cell density (0.87x10⁶ cells/P60, range 0.3–1.6x10⁶) at stationary phase relative to control cells (2.2x10⁶ cells/P60, range 1.7–2.6x10⁶; F_4,77=56.1, p<0.01, indicating that OI cells are larger than normal). Cell shape (expressed as the width: length ratio) was also abnormal in OI cells. (F_4,730=37.6, p<0.01), types I and II OI cells have significantly increased ratios (p<0.01) relative to control, type III, and type IV cells. Intra-group phenotypic heterogeneity was also apparent in the OI categories and also within the control population. These findings confirm deviant morphologic phenotypes in OI dermal fibroblasts and further demonstrate interindividual heterogeneity in the expression of genes that determine size and shape of dermal fibroblasts in both OI and normal donors.Publication No. 84013 from the Montreal Children's Hospital Research Institute