Mitochondrial DNA polymorphisms in subterranean mole-rats of the Spalax ehrenbergi superspecies in Israel, and its peripheral isolates

Patterns of mitochondrial DNA (mtDNA) variation were examined in 133 mole-rats constituting all four chromosomal species (2n = 52, 2n = 54, 2n = 58, and 2n = 60) of the Spalax ehrenbergi superspecies in Israel, as well as the peripheral isolates of 2n = 60. In the main range of the complex, a total of 28 mtDNA haplotypes were found in 64 mole-rats, with most haplotypes being unique to either a single chromosomal species or population. mtDNA divergence increased from low to high diploid number in a north-to-south direction in Israel. Overall levels of mtDNA diversity were unexpectedly the highest in the 2n = 60, the youngest species of the complex. The mtDNA haplotypes can be separated into two major groups, 2n = 52-54 and 2n = 58-60, and a phylogenetic analysis for each group revealed evidence of a few haplotypes not sorted by diploid number. The overall patterns of mtDNA divergence seen within and among the four chromosomal species are consistent with the parapatric mode of speciation as suggested from previous studies of allozyme and DNA hybridization. In a separate data set the patterns of mtDNA variation were examined across the main geographic range and across peripheral semi-isolates and isolates of the 2n = 60 chromosomal species. Fifteen haplotypes were found in 69 mole-rats. High levels of mtDNA diversity characterized the main range, semi-isolated, and even some desert isolated populations. The peripheral isolates contain much mtDNA diversity, including novel haplotypes.      

Cloning and nucleotide sequence of human liver cDNA encoding for cystathionine gamma-lyase.

We have cloned and sequenced a full-length cDNA (1083 bp) encoding the human liver cystathionine-gamma-lyase enzyme (cystathionase). The human cystathionase sequence presented a substantial deletion of 132 bases (44 amino acids) compared to that reported for rat cystathionase, and of 135 bases (45 amino acids) compared to that reported for yeast cystathionase. After re-alignment for the missing nucleotides, the human cDNA sequence shows significant amino acid homology to that for the rat enzyme (85%) and the yeast enzyme (50%). A search for an undeleted cDNA, by the polymerase chain reaction, yielded a second clone which contained the missing 132 bases. Flanking nucleotides in the latter clone were identical to those in the cDNA clone containing the deletion. The two forms of human cystathionase deduced from the two cDNA clones may be derived from two different genes or may be splice variants.     

Pre-clinical and clinical significance of heparanase in Ewing's sarcoma

Heparanase is an endoglycosidase that specifically cleaves heparan sulphate side chains of heparan sulphate proteoglycans, activity that is strongly implicated in cell migration and invasion associated with tumour metastasis, angiogenesis and inflammation. Heparanase up-regulation was documented in an increasing number of human carcinomas, correlating with reduced post-operative survival rate and enhanced tumour angiogenesis. Expression and significance of heparanase in human sarcomas has not been so far reported. Here, we applied the Ewing's sarcoma cell line TC71 and demonstrated a potent inhibition of cell invasion in vitro and tumour xenograft growth in vivo upon treatment with a specific inhibitor of heparanase enzymatic activity (compound SST0001, non-anticoagulant N-acetylated, glycol split heparin). Next, we examined heparanase expression and cellular localization by immunostaining of a cohort of 69 patients diagnosed with Ewing's sarcoma. Heparanase staining was noted in all patients. Notably, heparanase staining intensity correlated with increased tumour size (P = 0.04) and with patients' age (P = 0.03), two prognostic factors associated with a worse outcome. Our study indicates that heparanase expression is induced in Ewing's sarcoma and associates with poor prognosis. Moreover, it encourages the inclusion of heparanase inhibitors (i.e. SST0001) in newly developed therapeutic modalities directed against Ewing's sarcoma and likely other malignancies.     

Les Cases de la Valenciana,a new early Miocene small-mammal locality from the Vallès-Penedès Basin (Catalonia,Spain)

Abstract

The Valles-Penedes Basin (Catalonia, Spain) is classical area for the study of Miocene land mammal faunas. Nevertheless, the early Miocene part of the record has deserved little attention as compared to younger intervals. Most notably, the small mammals of this age have not been described in detail, consequently hampering the correlation of the Valles-Penedes record with other chronological schemes. In this work we describe the rich and diverse small mammal fauna from Les Cases de la Valenciana site (Gelida, Alt Penedès) which includes marsupials, eulipotyphlans, lagomorphs and rodents. On the basis of the presence of the cricetids Megacricetodon and Democricetodon this site is correlated with European Neogene zone MN4, yielding an age of 17–16 Ma. However, the rodent assemblage is comparable to that of chronologically close localities of the Calatayud-Montalbán Basin (Aragon, Spain), indicating that the same biochronological scheme can be applied to both areas. In this way, the coexistence of the eomyids Ligerimys ellipticus and Ligerimys florancei coupled with the presence of Megacricetodon primitivus indicates a correlation with local biozone Ca of the Calatayud-Montalban Basin, ranging from 16.3 to 16 Ma. Finally, the correlation of other early Miocene sites of the Valles-Penedes Basin is discussed and refined.     

The effects of prolonged deep freezing on the biomechanical properties of osteochondral allografts

Musculo-skeletal allografts sterilized and deep frozen are among the most common human tissue to be preserved and utilized in modern medicine. The effects of a long deep freezing period on cortical bone has already been evaluated and found to be insignificant. However, there are no reports about the influences of a protracted deep freezing period on osteochondral allografts. One hundred osteochondral cylinders were taken from a fresh specimen and humeral heads of 1 year, 2 years, 3 years and 4 year old bones. Twenty chips from each period, with a minimum of 3 chips per humeral head. Each was mechanically tested by 3 point compression. The fresh osteochondral allografts were significantly mechanically better than the deep frozen osteochondral allografts. There was no statistical significant time dependent difference between the deep frozen groups in relation to the freezing period. Therefore, we conclude that, from the mechanical point of view deep freezing of osteochondral allografts over a period of 4 years, is safe without further deterioration of the biomechanical properties of the osteochondral allografts.     

Luminescence properties of the Ln–EDTA complexes covalently linked to the chitosan biopolymers containing β‐diketonate as antenna ligands

This paper reports on the preparation, characterization, and photoluminescence properties of novel hybrid materials, in which the EDTA–Ln–L complexes (where L: H₂O, acac, bzac, dbm, and tta ligands, and Ln: Eu, Gd, and Tb) were covalently linked to the precursor medium molecular weight chitosan surface (CS) matrices or on the chitosan surfaces previously crosslinked with epichlorohydrin (CSech). The emission spectra of these materials were characterized by intraconfigurational‐4fN transitions centred on the Eu³⁺ and Tb³⁺ ions. Some broad bands from the polymeric matrix were also observed in the emission spectra, however the relative intensities of the intraconfigurational bands increased significantly for systems containing diketonate ligands when the antenna effect became more efficient. The values of the radiative rates (A_rad) were higher for crosslinked hybrid systems with epichlorohydrin, while nonradiative rates (A_nrad) presented the opposite behaviour. These data contributed to an increase in the values of emission quantum efficiency (η) for crosslinked materials. The effect of the modification process and antenna ligand on the values of intensities, intensity parameters Ω₂ e Ω₄ of the Eu³⁺ complexes were also investigated. The results showed that the crosslinked biopolymer surfaces have great potential for applications in molecular devices light converters.