Urinary cytologic abnormalities in bone marrow transplant recipients of cyclosporin

The role of urinary cytology in the early diagnosis of cyclosporin nephrotoxicity was studied in 20 bone marrow transplant recipients. There was an evident cyclosporin cytopathy in 35% of bone marrow transplant recipients examined, consisting mainly of degenerative and necrotic abnormalities in cells of the proximal convoluted tubules seen in urinary samples. These findings regressed to normal after reduction of the cyclosporin dose. Urinary cytology proved to be a useful method for the early diagnosis of cyclosporin nephrotoxicity.     

The ability of an environmental isolate of Pseudomonas fluorescens to utilize chrysene and other four-ring polynuclear aromatic hydrocarbons

A Pseudomonas fluorescens strain isolated from exhausted-oil-polluted soil was selected for its ability to grow on and degrade chrysene as a sole carbon source. The same strain was able to grow on and degrade benz[a]anthracene, benzo[b]naphthothiophene, but not benz[a]acridine. After 2 days of incubation on a mineral medium supplemented with chrysene at 1 g/ml, reached by adding the Polynuclear aromatic hydrocarbon dissolved in a water-miscible solvent to the medium, the cell number had increased by 10²–10³. The biodegradation rate followed first-order kinetics and at its maximum value was independent of substrate concentration, as happens when the substrates are solubilized.     

Fatty acid acylation of lens fiber plasma membrane proteins. MP26 and alpha-crystallin are palmitoylated

We describe in this report the fatty acylation of some of the main polypeptides from the eye lens fibers. MP26, the major lens fiber plasma membrane protein, and probably MP22, its natural degradation product, are palmitoylated in a post-translational process. This is also the case for alpha-crystallin, a major cytoplasmic structural protein shown to interact directly with the plasma membrane. Furthermore, a 65 kDa non-identified polypeptide and a high molecular weight component are also modified in the same way.     

MAP kinase-dependent degradation of p27Kip1 by calpains in choroidal melanoma cells. Requirement of p27Kip1 nuclear export

We investigated the status and the regulation of the cyclin-dependent kinases (CDK) inhibitor p27(Kip1) in a choroidal melanoma tumor-derived cell line (OCM-1). By contrast to normal choroidal melanocytes, the expression level of p27(Kip1) was low in these cells and the mitogen-activated protein (MAP) kinase pathway was constitutively activated. Genetic or chemical inhibition of this pathway induced p27(Kip1) accumulation, whereas MAP kinase reactivation triggered a down-regulation of p27(Kip1) that could be partially reversed by calpain inhibitors. In good accordance, ectopic expression of the cellular calpain inhibitor calpastatin led to an increase of endogenous p27(Kip1) expression. In vitro, p27(Kip1) was degraded by calpains, and OCM-1 cell extracts contained a calcium-dependent p27(Kip1) degradation activity. MAP kinase inhibition partially inhibited both calpain activity and calcium-dependent p27(Kip1) degradation by cellular extracts. Immunofluorescence labeling and subcellular fractionation revealed that p27(Kip1) was in part localized in the cytoplasmic compartment of OCM-1 cells but not of melanocytes, and accumulated into the nucleus upon MAP kinase inhibition. MAP kinase activation triggered a cytoplasmic translocation of the protein, as well as a change in its phosphorylation status. This CRM-1-dependent cytoplasmic translocation was necessary for MAP kinase- and calpain-dependent degradation. Taken together, these data suggest that in tumor-derived cells, p27(Kip1) could be degraded by calpains through a MAP kinase-dependent process, and that abnormal cytoplasmic localization of the protein, probably linked to modifications of its phosphorylation state, could be involved in this alternative mechanism of degradation.     

The p42/p44 mitogen-activated protein kinase activation triggers p27Kip1 degradation independently of CDK2/cyclin E in NIH 3T3 cells.

The p42/p44 mitogen-activated protein (MAP) kinase is stimulated by various mitogenic stimuli, and its sustained activation is necessary for cell cycle G(1) progression and G(1)/S transition. G(1) progression and G(1)/S transition also depend on sequential cyclin-dependent kinase (CDK) activation. Here, we demonstrate that MAP kinase inhibition leads to accumulation of the CDK inhibitor p27(Kip1) in NIH 3T3 cells. Blocking the proteasome-dependent degradation of p27(Kip1) impaired this accumulation, suggesting that MAP kinase does not act on p27(Kip1) protein synthesis. In the absence of extracellular signals (growth factors or cell adhesion), genetic activation of MAP kinase decreased the expression of p27(Kip1) as assessed by cotransfection experiments and by immunofluorescence detection. Importantly, MAP kinase activation also decreased the expression of a p27(Kip1) mutant, which cannot be phosphorylated by CDK2, suggesting that MAP kinase-dependent p27(Kip1) regulation is CDK2-independent. Accordingly, expression of dominant-negative CDK2 did not impair the down-regulation of p27(Kip1) induced by MAP kinase activation. These data demonstrate that the MAP kinase pathway regulates p27(Kip1) expression in fibroblasts essentially through a degradation mechanism, independently of p27(Kip1) phosphorylation by CDK2. This strengthens the role of this CDK inhibitor as a key effector of G(1) growth arrest, whose expression can be controlled by extracellular stimuli-dependent signaling pathways.     

Mouse Genome-Wide Association Mapping Needs Linkage Analysis to Avoid False-Positive Loci

We carried out genome-wide association (GWA) studies in inbred mouse strains characterized for their lung tumor susceptibility phenotypes (spontaneous or urethane-induced) with panels of 12,959 (13K) or 138,793 (140K) single-nucleotide polymorphisms (SNPs). Above the statistical thresholds, we detected only SNP rs3681853 on Chromosome 5, two SNPs in the pulmonary adenoma susceptibility 1 (Pas1) locus, and SNP rs4174648 on Chromosome 16 for spontaneous tumor incidence, urethane-induced tumor incidence, and urethane-induced tumor multiplicity, respectively, with the 13K SNP panel, but only the Pas1 locus with the 140K SNP panel. Haplotype analysis carried out in the latter panel detected four additional loci. Loci reported in previous GWA studies failed to replicate. Genome-wide genetic linkage analysis in urethane-treated (BALB/c×C3H/He)F2, (BALB/c×SWR/J)F2, and (A/J×C3H/He)F2 mice showed that Pas1, but none of the other loci detected previously or herein by GWA, had a significant effect. The Lasc1 gene, identified by GWA as a functional element (Nat. Genet., 38:888–95, 2006), showed no genetic effects in the two independent intercross mouse populations containing both alleles, nor was it expressed in mouse normal lung or lung tumors. Our results indicate that GWA studies in mouse inbred strains can suffer a high rate of false-positive results and that such an approach should be used in conjunction with classical linkage mapping in genetic crosses.     

Dry stone walls favour biodiversity: a case-study from the Appennines

One of the classical and traditional wall typology built in agricultural or pastoral landscapes are dry stone walls (walls built only of stones without concrete). These vertical surfaces are expected to increase habitat heterogeneity and to play an important role for biodiversity. This study focused on two groups of organisms: amphibians, represented by the rock-dwelling salamander Hydromantes strinatii, that are expected to use walls mainly as shelters, and molluscs, which use of walls may be affected mainly by the trophic resources available. A mountain area of the northern Appennines (NW-Italy) was surveyed to assess the differences between dry stone walls and the wall typologies in terms of morphology, surrounding landscape and salamander and mollusc occurrence; the relationships between wall typology features and salamander and mollusc distribution were assessed. Dry stone walls were more heterogeneous than concrete walls and hosted more lichens than natural rocky walls. They were more used by H. strinatii juveniles than the other walls and played an important role for their distribution. They were positively related to the occurrence of several molluscan species, including species with high ecological plasticity and rock-dwelling species. Among wall features, the most important for molluscs species distribution was vegetation cover, followed by lichen cover and heterogeneity, confirming the importance of trophic content for mollusc exploitation, while vegetated without concrete walls hosted higher number of species. The results suggest that dry stone walls can be important for fauna biodiversity and should be maintained and preserved as a part of landscape management.