Three-dimensional geometric morphometrics of Arvicanthis: implications for systematics and taxonomy

Arvicanthis is an African murid, found throughout sub-Saharan Africa, Sudan and Egypt. Although in the past 10 years several studies have been carried out to assess its systematics, there is still a need for a general revision of the genus. In this study the morphometric relationships between 71 populations throughout the range were investigated. A three-dimensional geometric morphometric approach was used to assess differences in the size and shape of the skull. These were related to the different biogeographical domains characterizing the range of the genus and to molecular and karyotypic phylogenies. Results agree only in part with phylogeny, and show a close relationship with the environmental backgrounds of each species. It is therefore suggested that the adaptation of Arvicanthis to local environment has played an important role in the phenotypic evolution of the skull. This leads to problems in taxonomic definitions based on morphometrics, which should not be used without comparison with other independently derived characters such as the DNA and the karyotype.     

DEVELOPMENTAL STUDIES IN PORPHYRA (BANGIOPHYCEAE). II. CHARACTERIZATIO OF THE MAJOR LECTIN BINDING GLYCOPROTEINS IN DIFFERENTIATED REGIONS OF THE PORPHYRA PERFORATA THALLUS1

Detergent soluble extracts of differentiated regions of the Porphyra perforata J. Ag. thallus (holdfast, rhizoidal, vegetative and reproductive cells) were fractionated on sodium dodecyl sulfate polyacrylamide gels. Glycoproteins were identified by their lectin affinity. Extracts from all areas of the thallus contained glycoproteins, but the staining patterns were different for each region with each of the lectins tested: concanavalin A, Ulex europeaus agglutinin, Ricinus communis agglutinin, soybean agglutinin and peanut agglutinin. These data indicate that the morphologically distinct regions of the thallus also differ biochemically. Analysis of the lectin blots revealed the presence of tissue-specific glycoproteins in the five thallus areas. Such unique glycoproteins could be used as markers of differentiation in this species.     

Activation of the inositol trisphosphate second messenger system by cAMP in a mouse fibroblast cell line

Intracellular Ca²⁺ mobilization events were assessed in mouse L cells, which contain native prostaglandin E₁ receptors and transfected human ₂ adrenergic receptors. Both Fura2 (single cell measurements) and Quin 2, (cuvette assays) were used to determine [Ca²⁺]_i levels. Our results demonstrate that in the transfected cells there is a dose-dependent increase in [Ca²⁺]_i in response to isoproterenol (0.1 nM–100 nM), which is inhibited by the -adrenergic antagonist, propranolol, and is a result of intracellular Ca²⁺ release. [Ca²⁺]₁ in these cells was also increased by prostaglandin E₁, 8 bromo cyclic AMP, and aluminum fluoride. Both 8 bromo cAMP and isoproterenol induced a rapid increase in the levels of IP₁, IP₂, and IP₃. The data presented demonstrate that the elevation of intracellular cyclic AMP induces an increase in IP₃ production which leads to an elevation in [Ca²⁺];. We propose that this cyclic AMP dependent activation of the IP₃ generating system occurs at a post-receptor site.Abbreviations cAMP Adenosine Cyclic 3-5-Monophosphate - [Ca²⁺]_i intracellular [Ca²⁺]_i - 8 Br cAMP 8 Bromo Adenosine Cyclic 3-5-Monophosphate - DAG Diacylglycerol - EGTA] [Ethylene Bis (oxyethylenenitrilo)] Tetracetic acid - BSA Bovine Serum Albumin - HBSS-H Hanks' Balanced Salt Solution buffered with HEPES to pH 7.4 - HEPES 4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid - PIP₂ Phosphatidylinositol 4,5-bisphosphate - IP₂ Inositol 4 Phosphate - IP₂ Inositol 4,5 Bisphosphate - IP₃ Inositol Trisphosphate - PGE₁ Prostaglandin E₁ - PBS Phosphate Buffered Saline Solution     

Adenosine deaminase activity in relation to the appearance of early and late Epstein-Barr virus antigens induced in lymphoblastoid cells

Summary Induction of Epstein-Barr virus (EBV) capsid antigen synthesis in 59.6% of P3HR-1 cells was followed by a decrease to 70% in adenosine deaminase (ADA) activity. In Daudi cells synthesizing EBV early antigen, ADA activity did not decrease.     

Interstrain Variation in Amylase Gene Copy Number and mRNA Abundance in Three Mouse Tissues

Amylase expression in strain YBR differs in several respects from the standard mouse phenotype. The synthesis of salivary amylase is elevated twofold in YBR mice and the synthesis of pancreatic amylase is reduced to one-half the normal rate. We have compared the concentrations of amylase mRNA in the parotid, liver and pancreas of YBR mice with those in strains A/J and C3H. We observed differences in amylase mRNA abundance which can account for the levels of amylase protein synthesis in the parotid and pancreas of these strains. Unexpectedly, the concentration of amylase mRNA in the liver of YBR mice was also higher than in the other strains. Since liver amylase is transcribed from the same gene as parotid amylase, duplication of the Amy-1 locus could account for the elevated mRNA concentration in both tissues. Quantitative analysis of genomic DNA by Southern blotting provided direct evidence for duplication of Amy-1 in strain YBR.