The phylogenetic position of the zokors (Myospalacinae) and comments on the families of muroids (Rodentia)

Recent molecular studies have concluded that the genus Myospalax evolved from within the rodent subfamily Cricetinae. This conclusion was tested using the complete sequences from the mitochondrial 12S rRNA and cytochrome b genes. Based on our analyses, Myospalax appears to be sister to a clade containing the subfamilies Spalacinae and Rhizomyinae, and all three of these lineages appear to be basal to the superfamily Muroidea. Based on the position of these three lineages, we suggest that they be placed in a distinct family, the Spalacidae, rather than subsumed as subfamilies in the family Muridae. Finally, our analyses suggest that the earlier placement of Myospalax as a member of the Cricetinae is the result of a single misidentified specimen, which was not a Myospalax.     

Parentage determination in maize hybrids using the arbitrarily primed polymerase chain reaction (AP-PCR)

Summary Using a novel procedure based on the polymerase chain reaction, we have developed a rapid, efficient, and economical method for identifying plant genotypes. The arbitrarily primed polymerase chain reaction (AP-PCR) generates reproducible fingerprints from any organism, without the need for DNA sequence information. These fingerprints include DNA fragment polymorphisms that can be (1) used for varietal identification and parentage determination, (2) followed in segregating populations produced by crosses, (3) used as markers for the construction of genetic maps, and (4) used to generate dendograms of phylogenetic relationships, especially at the intraspecific level. AP-PCR requires only minute quantities of DNA (10–25 ng per reaction) and therefore can be used in situations in which DNA is limiting. We demonstrate the use of AP-PCR to identify inbred parents of hybrid maize plants in double-blind experiments.     

Genetic evidence for key roles of decorin and biglycan in dentin mineralization

Targeted disruption of the dentin sialophosphoprotein (DSPP) gene in the mice (Dspp^?/?) results in dentin mineralization defects with enlarged predentin phenotype similar to human dentinogenesis imperfecta type III. Using DSPP/biglycan (Dspp^?/?Bgn^?/0) and DSPP/decorin (Dspp^?/?Dcn^?/?) double knockout mice, here we determined that the enlarged predentin layer in Dspp^?/? teeth is rescued in the absence of decorin, but not in the absence of biglycan. However, Fourier transform infrared (FTIR) spectroscopy analysis reveals similar hypomineralization of dentin in both Dspp^?/?Bgn^?/0 and Dspp^?/?Dcn^?/? teeth. Atomic force microscopy (AFM) analysis of collagen fibrils in dentin shows subtle differences in the collagen fibril morphology in these genotypes. The reduction of enlarged predentin in Dspp^?/?Dcn^?/? mice suggests that the elevated level of decorin in Dspp^?/? predentin interferes with the mineralization process at the dentin mineralization front. On the other hand, the lack of DSPP and biglycan leads to the increased number of calcospherites in Dspp^?/?Bgn^?/0 predentin, suggesting that a failure in coalescence of calcospherites was augmented in Dspp^?/?Bgn^?/0 teeth as compared to Dspp^?/? teeth. These findings indicate that normal expression of small leucine rich proteoglycans, such as biglycan and decorin, plays an important role in the highly orchestrated process of dentin mineralization.     

Multi-locus phylogeny of dolphins in the subfamily Lissodelphininae: character synergy improves phylogenetic resolution

Background  

Dolphins of the genus Lagenorhynchus are anti-tropically distributed in temperate to cool waters. Phylogenetic analyses of cytochrome b sequences have suggested that the genus is polyphyletic; however, many relationships were poorly resolved. In this study, we present a combined-analysis phylogenetic hypothesis for Lagenorhynchus and members of the subfamily Lissodelphininae, which is derived from two nuclear and two mitochondrial data sets and the addition of 34 individuals representing 9 species. In addition, we characterize with parsimony and Bayesian analyses the phylogenetic utility and interaction of characters with statistical measures, including the utility of highly consistent (non-homoplasious) characters as a conservative measure of phylogenetic robustness. We also explore the effects of removing sources of character conflict on phylogenetic resolution.     

Bilateral detection thresholds in dextrals and sinistrals reflect the more sensitive side of the nose, which is not lateralized [published erratum appears in Chem Senses 1998 Dec;23(6):761]

Several fundamental questions remain enigmatic concerning human olfactorysensitivity, including (i) whether detection threshold differences existbetween the two sides of the nose (and, if so, whether such differences areinfluenced by handedness) and (ii) whether bilateral (i.e. binasal)stimulation leads to lower thresholds than unilateral stimulation (and, ifso, whether the degree of facilitation is inversely related to generalolfactory ability). In this study, and well-validated single staircaseprocedure was used to establish bilateral and unilateral detectionthresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130right- and 33 left-handed subjects. No differences in sensitivity betweenthe left and right sides of the nose were observed in either group.Bilateral thresholds were lower, on average, than unilateral thresholdswhen the latter were categorized in terms of left and right nares. However,the bilateral thresholds did not differ significantly from those of theside of the nose with the lower threshold. Overall smell ability, asmeasured by the University of Pennsylvania Smell Identification Test, didnot interact with any of the test measures. These data imply that (i) theleft and right sides of the nose do not systematically differ in detectionthreshold sensitivity for either dextrals or sinistrals and (ii) if centralintegration of left:right olfactory threshold sensitivity occurs, itseffects do not exceed the function of the better side of the nose.     

Calcium deposition in osteoarthritic meniscus and meniscal cell culture

Introduction  

Calcium crystals exist in the knee joint fluid of up to 65% of osteoarthritis (OA) patients and the presence of these calcium crystals correlates with the radiographic evidence of hyaline cartilaginous degeneration. This study sought to examine calcium deposition in OA meniscus and to investigate OA meniscal cell-mediated calcium deposition. The hypothesis was that OA meniscal cells may play a role in pathological meniscal calcification.