Pathomorphological reactions and noradrenalin content of the heart after administration of depot angiotensin in trained and untrained rats

A 14-days' training of rats designed to adapt the animals to the procedure of blood-pressure measurement caused in the myocardium a decrease, in serum an increase in noradrenaline ( NA) content. The latter remained unchanged following 3 days of treatment with 2.5 mg depot angiotensin II (AII) but decreased by more than one-half in the myocardium of untreated animals, and increased in serum. Despite the considerable difference in myocardial NA content and blood-pressure behaviour, both trained and untrained rats showed the same morphological reactions following administration of A II. These myocardial alterations which largely correspond to the so-called epinephrine myocarditis should not therefore be due solely to NA action; rather, the involvement of A II should be considered also.     

Accurate MS-based Rab10 Phosphorylation Stoichiometry Determination as Readout for LRRK2 Activity in Parkinson's Disease

1. Download : Download high-res image (63KB)
2. Download : Download full-size image

Highlights

• •MS-based clinical assay that accurately determines phospho Rab10 occupancy.
• •Stable isotope labeled phosphopeptide injected as a standard with endogenous tryptic phospho Rab peptide for accurate ratio determination.
• •Determination of pRab levels in neutrophils of Parkinson disease patients.
• •Relevance of pRab levels as marker of PD.

     

Elimination of Von Hippel-Lindau Function Perturbs Pancreas Endocrine Homeostasis in Mice

Mutations in the human homolog of the Vhlh gene [encoding the von-Hippel Lindau (VHL) protein] lead to tumor development. In mice, depletion of Vhlh in pancreatic ß-cells causes perturbed glucose homeostasis, but the role of this gene in other pancreatic cells is poorly understood. To investigate the function of VHL/HIF pathway in pancreatic cells, we inactivated Vhlh in the pancreatic epithelium as well as in the endocrine and exocrine lineages. Our results show that embryonic depletion of Vhlh within the pancreatic epithelium causes postnatal lethality due to severe hypoglycemia. The hypoglycemia is recapitulated in mice with endocrine-specific removal of Vhlh, while animals with loss of Vhlh predominantly in the exocrine compartment survive to adulthood with no overt defects in glucose metabolism. Mice with hypoglycemia display diminished insulin release in response to elevated glucose. Significantly, the glucagon response is impaired both in vivo (circulating glucagon levels) as well as in an in vitro secretion assay in isolated islets. Hypoxia also impairs glucagon secretion in a glucagon-expressing cell line in culture. Our results reveal a novel role for the hypoxia/HIF pathway in islet hormone secretion and maintenance of the fine balance that allows for the establishment of normoglycemia.     

Structural and Functional Impact of SRP54 Mutations Causing Severe Congenital Neutropenia

1. Download : Download high-res image (235KB)
2. Download : Download full-size image

     

Tomato protoplast DNA transformation: physical linkage and recombination of exogenous DNA sequences

Tomato protoplasts have been transformed with plasmid DNA's, containing a chimeric kanamycin resistance gene and putative tomato origins of replication. A calcium phosphate-DNA mediated transformation procedure was employed in combination with either polyethylene glycol or polyvinyl alcohol. There were no indications that the tomato DNA inserts conferred autonomous replication on the plasmids. Instead, Southern blot hybridization analysis of seven kanamycin resistant calli revealed the presence of at least one kanamycin resistance locus per transformant integrated in the tomato nuclear DNA. Generally one to three truncated plasmid copies were found integrated into the tomato nuclear DNA, often physically linked to each other. For one transformant we have been able to use the bacterial ampicillin resistance marker of the vector plasmid pUC9 to rescue a recombinant plasmid from the tomato genome. Analysis of the foreign sequences included in the rescued plasmid showed that integration had occurred in a non-repetitive DNA region. Calf-thymus DNA, used as a carrier in transformation procedure, was found to be covalently linked to plasmid DNA sequences in the genomic DNA of one transformant. A model is presented describing the fate of exogenously added DNA during the transformation of a plant cell. The results are discussed in reference to the possibility of isolating DNA sequences responsible for autonomous replication in tomato.     

Preparation of megabase-sized tomato DNA and separation of large restriction fragments by field inversion gel electrophoresis (FIGE)

The Schwartz and Cantor technique for releasing and fractionating megabase-sized DNA from agarose-embedded cells is beginning to bridge the gap in resoluation between classical genetics and current molecular DNA techniques, particularly in mammalian systems. As yet no conditions have been described for preparing plant DNA that is of sufficient length to allow similar long-range restriction mapping experiments in plant systems. In this report, we describe the application of the Schwartz and Cantor technique for preparing high molecular weight DNA from embedded tomato leaf protoplasts, as well as conditions for generating and fractionating large restriction fragments, by field inversion gel electrophoresis (FIGE). The bulk of DNA released from lysed protoplasts was at least 2 Mb in size and amenable to restriction digestion as shown by hybridizing Southern blots with, among others, a probe for the Adh-2 gene of tomato. Restriction fragments as large as 700 kb were detected. Chloroplast DNA is isolated intact, amenable to restriction analysis and, in its native form, not mobile in FIGE.