Cryptic diversity in the lizard genus Plica (Squamata): phylogenetic diversity and Amazonian biogeography

Intra‐ and interspecific genetic diversity of the lizard species Plica plica (9 localities) and Plica umbra (19 localities) from the Brazilian Amazon was analysed using two mitochondrial (16S rDNA and CO1) and one nuclear (prolactin receptor – PRLR) genes. We generated a maximum‐likelihood and Bayesian hypotheses of phylogenetic relationships, and using the bPTP and ABGD lineage delimiting methods inferred the most likely number of lineages within each species. Both methods delimited five distinct lineages in Plica plica and six lineages within Plica umbra. The nominal subspecies of Plica umbra was comprised of one lineage, while Plica umbra ochrocollaris was comprised of five lineages. In majority of the cases, lineages were restricted to the interfluves of major Amazonian rivers, and different lineages occupied distinct areas of endemism. Phylogenetic relationships of the lineages are largely concordant with the hypothesized formation of the areas of endemism. The geographic structuring of the clades and the delimitation of these clades as distinct lineages suggest the possibility that these lineages represent species. If the observed diversity of lineages within the genus Plica is characteristic of squamate reptiles of the Amazon region, the diversity of squamates is grossly underestimated.     

Matrix Metalloproteases and Tissue Inhibitors of Metalloproteinases in Medial Plica and Pannus-like Tissue Contribute to Knee Osteoarthritis Progression

Osteoarthritis (OA) is characterized by degradation of the cartilage matrix, leading to pathologic changes in the joints. However, the pathogenic effects of synovial tissue inflammation on OA knees are not clear. To investigate whether the inflammation caused by the medial plica is involved in the pathogenesis of osteoarthritis, we examined the expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), interleukin (IL)-1β, and tumor necrosis factor (TNF)-α in the medial plica and pannus-like tissue in the knees of patients with medial compartment OA who underwent either arthroscopic medial release (stage II; 15 knee joints from 15 patients) or total knee replacement (stage IV; 18 knee joints from 18 patients). MMP-2, MMP-3, MMP-9, IL-1β, and TNF-α mRNA and protein levels measured, respectively, by quantitative real-time PCR and Quantibody human MMP arrays, were highly expressed in extracts of medial plica and pannus-like tissue from stage IV knee joints. Immunohistochemical staining also demonstrated high expression of MMP-2, MMP-3, and MMP-9 in plica and pannus-like tissue of stage IV OA knees and not in normal cartilage. Some TIMP/MMP ratios decreased significantly in both medial plica and pannus-like tissue as disease progressed from stage II to stage IV. Furthermore, the migration of cells from the pannus-like tissue was enhanced by IL-1β, while plica cell migration was enhanced by TNF-α. The results suggest that medial plica and pannus-like tissue may be involved in the process of cartilage degradation in medial compartment OA of the knee.     

Meiosis in man

The study of human meiosis impinges on clinically important areas such as infertility and aneuploidy, and an understanding of the behaviour of chromosomes in the germ line is essential for those engaged in genetic counselling. Recent advances in cytological techniques are allowing detailed observation of chromosomes in the prophase stage. Important problems such as the effects of structural and numerical chromosome abnormalities, and the relationship between abnormal meiotic chromosome behaviour and germ-cell death are being explored, while studies on mouse oocytes are beginning to shed light on the basis of the maternal age effect for aneuploidy such as in Down syndrome in man. Work at the molecular level promises to yield further advances.     

Cowpox in man

Two cases of human infection caused by vaccinia virus were recorded in the Rzeszów province (Poland), this infection being absent both in this province and in the whole country for many years. The diagnosis was based on the investigation of isolated samples (from one female patient) and the identification of the causative agent by its biological properties and the results of the analysis of its genome, made with the use of restrictases, as well as on the results of the serological investigation. Of the two female patients, one suffered from a prolonged and severe infection in her eye, the other had a lesion on the backside of her hand. Apart from local lesions, systemic phenomena (fever, malaise, headache) were observed in both patients. The authors state that, most likely, rodents were the source of infection in these two cases. This is confirmed by the fact that wild rodents (rats, mice) caught in the focus of infection show the presence of antibodies to orthopoxviruses.