Cellular distribution and amount of chromogranin A in bovine endocrine pancreas

We determined the cellular distribution and the amount of chromogranin A in endocrine cells of bovine pancreas using a polyclonal antibody against bovine adrenomedullary chromogranin A. The relative amounts of chromogranin A in the different cells of the endocrine pancreas were determined by computer-assisted analyses of the optical densities of the immunoreactivities in the stained sections. More than 80% of the immunoreactive chromogranin A was located in the pancreatic B-cells. In immunoblots of acid tissue extracts, only one chromogranin A band (MW 74 KD) was observed. Quantification of the immunoblots revealed that 3 micrograms of chromogranin A and 918 micrograms of insulin were present per gram pancreas (wet weight), equivalent to a molar ratio of 460 mumol chromogranin A per mol insulin

Chromogranin A in the pancreatic islet

Chromogranin A (CGA) is the major soluble protein within secretory vesicles of chromaffin cells. A polyclonal antiserum was raised against bovine CGA and characterized in two-dimensional immunoblots. Cellular and subcellular distribution of CGA in bovine pancreatic islet was investigated by immunocytochemistry. At the light microscopic level, CGA-like immunoreactivity was found in the same cells that react with antibodies against insulin, glucagon, and somatostatin. A minority of cells containing pancreatic polypeptide also showed faint immunostaining. At the ultrastructural level (protein A-gold technique), CGA-like immunoreactivity was confined exclusively to the secretory vesicles. Whereas the hormones were localized mainly in the central part of the secretory vesicles, CGA was present predominantly in the periphery. These findings indicate that a CGA-like protein is a regular constituent of the matrix of secretory vesicles in pancreatic endocrine cells

Geographic Variation of Cirques on Iceland: Factors Influencing Cirque Morphology

Cirques are one of the most common glacial landforms in alpine settings. They also provide important paleoclimate information (e.g. Meierding 1984; Evans 2006). The purpose of this study is to fill in gaps in the climate record of Iceland by conducting a quantitative analysis of cirques in three regions in Iceland: Tröllaskagi, the East Fjords, and Vestfirðir. Iceland, located in the center of the North Atlantic Ocean, contains many small glaciers, in addition to large ice caps. The glaciers on Iceland are particularly sensitive to variations in oceanic and atmospheric circulation (Andresen et al. 2005; Geirsdóttir et al., 2009; Ólafsdóttir et al. 2010). Iceland thus provides an excellent case study to examine factors influencing glacial landforms such as cirques. (excerpt

Assessment of the genetic diversity of native apple cultivars in the south eastern ranges of the Alps with three selected microsatellite loci

The regional diversity of native apple cultivars in parts of the south eastern ranges of the Alps (Styria, Austria and northern parts of Slovenia) was examined. As the application of conventional pomological methods to characterise cultivars may sometimes be ambiguous, we regard the application of molecular methods to be essential for thorough cultivar diversity assessments. Five hundred samples were collected from different climatic and edaphic regions and analysed using three selected microsatellite loci. With this approach we were able to distinguish 190 named varieties at which we chose 50 as reference varieties. The high diversity of native races suggests that the Southern alpine ranges represent a „hot spot“ of cultivar diversity. This can be attributed to historical effects and the local persistence of a traditional management practice with orchards of widely spaced and old-grown trees of various races. Because these „old“ native races could harbour interesting genetic traits (pathogen resistance, taste, etc.) that will be important in future food production, measures for their conservation are overdue. Our approach will not only show which local cultivars/genotypes require rapid action for their protection, but due to the international nature of our project we can also show which old and untraceable local names in different languages correspond with the same cultivars

A phylogenetic study of the Lecanora rupicola group (Lecanoraceae, Ascomycota)

A molecular phylogeny of the Lecanora rupicola group is presented, based on ITS sequence analyses. The study includes saxicolous and corticolous members of the Lecanora rupicola group as well as other Lecanora species with pruinose apothecia. A phylogenetic hypothesis for species in Lecanora s. lat. and various other genera in Lecanoraceae, based on an alignment-free distance estimation technique, shows that the Lecanora rupicola group forms a monophyletic clade within Lecanoraceae. Affinities to the core group of Lecanora are not well supported, likewise the monophyly of Lecanora s. str. with other species groups in Lecanora, such as the lobate taxa (and Rhizoplaca) is not supported. A more detailed analysis involving Lecanora species with pruinose apothecial discs was carried out with model-based Bayesian Markov chain Monte Carlo (B/MCMC) tree sampling. The results suggest the monophyly of the Lecanora species that are characterized by the presence of chromones. Corticolous as well as saxicolous species are included. Lepraria flavescens is closely related to the Lecanora swartzii subgroup, and the new name Lecanora rouxii nom. nov. is introduced for that species. Other Lecanora species with pruinose discs are riot closely related to the Lecanora rupicola group