Mutational analysis of the human cyclin-dependent kinase inhibitor p27kip1 in primary breast carcinomas

The human p27^kip1 gene encodes a cyclin-dependent kinase inhibitor implicated in the negative regulation of the cell cycle. In order to elucidate the possible role of p27 mutations in the development or progression of human breast cancer, we have studied the occurrence of genetic abnormalities in this gene in a series of 30 primary breast carcinomas. Direct sequence analysis of the polymerase chain reaction amplified human p27 gene revealed the occurrence of two sequence variations with respect to the reported sequence; both variants were also present in the lymphocyte DNA from the same patients. First, a silent G to A change at codon 142 (Thr) was detected in a single case. Second, a T to G transversion at codon 109, resulting in a Val to Gly change, was observed in eight tumour DNA samples (26%) and in 31 out of 80 unrelated normal individuals (39%). This latter change creates a BglI restriction site that might be useful for genetic analysis of human tumours. Despite the occurrence of these polymorphisms, we did not however find any evidence of somatic mutations in the coding region of the p27 gene. On the basis of these results, we suggest that alterations in the integrity of the human p27 gene are not common events in human breast carcinomas.     

Demographic and tumour prevalence data for juvenile green turtles at the Coastal-Marine Protected Area of Cerro Verde,Uruguay

Marine Protected Areas are increasingly considered in coastal areas as an instrument to preserve threatened fauna and fragile habitats from the detrimental effects of human activities. For this reason baseline data are of utmost importance for the evaluation of the outcomes of ongoing conservation efforts. Along the Uruguayan coast, the area of Cerro Verde (declared protected since 2011) represents the most important foraging and development area for green turtles (Chelonia mydas). Between 2002 and 2009, a long-term capture-mark-recapture programme for green turtles was developed to gather data on demography, ecology and status of the species in the area. Turtles captured were juveniles ranging from 28.8 to 64.3?cm in length over the curve of the carapace (n?=?514), and results indicated a size-based habitat segregation. Tumour prevalence was 5.3% (n?=?27) and was positively correlated with carapace length. The mean body condition index was 1.25?±?0.14 (n?=?494). From the total number of tagged turtles 10.6% were recaptured during the study period. Green turtles showed high site fidelity; 81% of the turtles were recaptured within the same season and 76% were recaptured in different seasons but were found at the original capture spot. Mean annual growth rate was 1.6?±?0.9?cm year^?1. The catch per unit effort of 2008 differed from 2009, higher in 2009, but also significantly different between capture spots. The present study constitutes a baseline dataset for future monitoring of green turtles in the area and provides valuable information for wider analyses of population dynamics in the Southwestern Atlantic Ocean.     

New insights on the comma-less theory.

The comma-less hypothesis represents a theoretical effort to describe one of the steps in the early evolution of the translation apparatus. This hypothesis emphasizes the advantages that a RNY coding pattern would have provided in a primitive RNA adaptor-catalyst system. This theory has been debated for years, both in conceptual and statistical terms, and no consensus about its validity has been ascertained. In this work, a statistical model refuting this theory was reconsidered. This new approach eliminates the bias due to the absence of stop codons in the open reading frame, and to the amino acid composition of bacterial genes. The results obtained support the biological significance of the RNY coding pattern.     

Distinct isoforms of ADPglucose pyrophosphatase and ADPglucose pyrophosphorylase occur in the suspension-cultured cells of sycamore (Acer pseudoplatanus L.)

The intracellular localizations of ADPglucose pyrophosphatase (AGPPase) and ADPglucose pyrophosphorylase (AGPase) have been studied using protoplasts prepared from suspension-cultured cells of sycamore (Acer pseudoplatanus L.). Subcellular fractionation studies revealed that all the AGPPase present in the protoplasts is associated with amyloplasts, whereas more than 60% of AGPase is in the extraplastidial compartment. Immunoblots of amyloplast- and extraplastid-enriched extracts further confirmed that AGPase is located mainly outside the amyloplast. Experiments carried out to identify possible different isoforms of AGPPase in the amyloplast revealed the presence of soluble and starch granule-bound isoforms. We thus propose that ADPglucose levels linked to starch biosynthesis in sycamore cells are controlled by enzymatic reactions catalyzing the synthesis and breakdown of ADPglucose, which take place both inside and outside the amyloplast.     

Human midbrain precursors activate the expected developmental genetic program and differentiate long-term to functional A9 dopamine neurons in vitro. Enhancement by Bcl-X(L)

Understanding the molecular programs of the generation of human dopaminergic neurons (DAn) from their ventral mesencephalic (VM) precursors is of key importance for basic studies, progress in cell therapy, drug screening and pharmacology in the context of Parkinson's disease. The nature of human DAn precursors in vitro is poorly understood, their properties unstable, and their availability highly limited. Here we present positive evidence that human VM precursors retaining their genuine properties and long-term capacity to generate A9 type Substantia nigra human DAn (hVM1 model cell line) can be propagated in culture. During a one month differentiation, these cells activate all key genes needed to progress from pro-neural and pro-dopaminergic precursors to mature and functional DAn. For the first time, we demonstrate that gene cascades are correctly activated during differentiation, resulting in the generation of mature DAn. These DAn have morphological and functional properties undistinguishable from those generated by VM primary neuronal cultures. In addition, we have found that the forced expression of Bcl-X(L) induces an increase in the expression of key developmental genes (MSX1, NGN2), maintenance of PITX3 expression temporal profile, and also enhances genes involved in DAn long-term function, maintenance and survival (EN1, LMX1B, NURR1 and PITX3). As a result, Bcl-X(L) anticipates and enhances DAn generation.     

Imidazo[1,2-a]pyrazines as novel PI3K inhibitors

Phosphoinositide-3-kinase (PI3K) is an important target for cancer therapeutics due to the deregulation of its signaling pathway in a wide variety of human cancers. We describe herein a novel series of imidazo[1,2-a]pyrazines as PI3K inhibitors.     

Distribution and status of the kelp gull, Larus dominicanus Lichtenstein (1823), at Admiralty Bay, King George Island, South Shetland, Antarctica

We examined the distribution, abundance and density of the kelp gull, at Admiralty Bay during three austral summers from 2002/03 to 2004/05 and compared our results with previously published data. All ice free areas within the bay were surveyed, and nests were individually marked with a hand-held GPS receiver and subsequently plotted on a geographical chart using ArcView (ESRI 2001). Statistical analysis demonstrated that the means are similar for all time periods, suggesting that the population of kelp gulls has remained unchanged in Admiralty Bay since summer of 1978/79 (Jablonski 1986).