Evolution of Metamorphism in Thymidylate Synthases Within the Primate Lineages

Crystal structures of human thymidylate synthase (hTS) revealed that the protein exists in active and inactive conformations, defined by the position of a loop containing the active site nucleophile. TS is highly homologous among diverse species; however, the residue at position 163 (hTS) differs among species. Arginine at this position is predicted by structural modeling to enable conformational switching. Arginine or lysine is reported at this position in all mammals in the GenBank and Ensembl databases, with arginine reported in only primates. Sequence analysis of the TS gene of representative primates revealed that arginine occurs at this relative position in all primates except a representative of prosimians. Mutant human proteins were created with residues at position 163 that occur in TSs from prokaryotes and eukaryotes. Catalytic constants (k _cat) of mutant enzymes were 45–149% of hTS, with the lysine mutant (R163K) exhibiting the highest k _cat. The effect of lysine substitution on solution structure and on ligand binding was investigated. R163K exhibited higher intrinsic fluorescence, a more negative molar ellipticity, and higher dissociation constants (K _d) for ligands that modulate protein conformation than hTS. Temperature effects on intrinsic fluorescence and catalytic activity of hTS and R163K are consistent with proteins populating different conformational states. The data indicate that the enzyme with arginine at the position corresponding to 163 (hTS) evolved after the divergence of prosimians and simians and that substitution of lysine by arginine confers unique structural and functional properties to the enzyme expressed in simian primates.     

The evaluation of knee bone mineral density following open-wedge high tibial osteotomy

Examinations of bone density changes in selected knee bone ends were evaluated prospectively in a randomized group of 28 patients, aged from 41 to 65 (mean: 55.3 years), who had varus deformations of their mechanic limb axes, mean 8 degrees. The examinations were conducted during the preoperative period, 10 days, 3, 6, and 12 weeks, as well as 6 and 12 months after the procedure. A statistically significant increase in bone density was observed in the medial tibial condyle area, while a statistically insignificant decrease of bone density was noted in the medial femoral condyles. Bone density increased in the lateral tibial condyle area, whereas there were no density changes in the area of the lateral femoral condyles. The research results demonstrate that the relief achieved in ailments after high tibial osteotomies does not directly correspond to the bone density of the affected areas.     

The MiSink Plugin: Cytoscape as a graphical interface to the Database of Interacting Proteins

The MiSink Plugin converts Cytoscape, an open-source bioinformatics platform for network visualization, to a graphical interface for the database of interacting proteins (DIP: http://dip.doe-mbi.ucla.edu). Seamless integration is possible by providing bi-directional communication between Cytoscape and any Web site supplying data in XML or tab-delimited format. Availability: MiSink is freely available for download at http://dip.doe-mbi.ucla.edu/Software.cgi.     

Oviposition Marking Behavior of <Emphasis Type="Italic">Diachasma alloeum</Emphasis>, (Hymenoptera: Braconidae), Parasitizing <Emphasis Type="Italic">Rhagoletis pomonella</Emphasis>, (Diptera: Tephritidae)

Diachasma alloeum (Muesebeck) (Hymenoptera: Braconidae) is a solitary larval endoparasitoid attacking Rhagoletis (Diptera: Tephritidae) species. Rhagoletis pomonella (Walsh) mark the surface of fruit after oviposition with an oviposition marking pheromone (OMP) which deters conspecific female flies. Herein we demonstrate that female D. alloeum wasps reared from either apple or hawthorn race R. pomenella larvae also deposit an OMP that reduces oviposition by conspecific female wasps. Significantly fewer wasps accepted fruit that had received prior wasp oviposition and OMP or OMP alone without oviposition compared with control fruit for a minimum of 7 days on both fruit types. Rinsing fruit with a 50% ethanol solution appeared to remove the OMP rendering fruit more acceptable for oviposition than marked fruit that was not rinsed. Wasps of each host race were able to detect and avoid the OMP of the sister race and fruit substrate type did not affect wasp response to the pheromone. The possibility of an internal marker deposited during oviposition is also discussed.     

The activity of selected glycosidases in salivary gland tumors

The monitoring of the patients after salivary gland tumors surgery is an important clinical issue. Still imperfect diagnostic procedures also remain a challenge for searching new sensitive and specific biomarkers of neoplastic processes in salivary glands. The aim of the presented study was an the assessment of the activity of HEX, with its isoforms HEX-A and HEX-B, GLU, GAL, MAN and FUC in salivary gland tumor tissues in comparison to a healthy salivary gland tissues taken during autopsy. A group of 42 patients with benign and malignant salivary gland tumors, aged 25-65 were examined. Fragments of salivary gland tumor tissue, fragments of healthy tissue removed during autopsy, blood serum and saliva were collected from patients with salivary gland tumors and healthy volunteers. In salivary gland tumor tissue the activity of HEX, HEX-A, HEX-B, GAL, FUC was considerably higher than in comparison to healthy salivary gland tissue and ascending trend of activity of GLU, MAN was also noticed. The activity of all lysosomal exoglycosidases in blood serum in patients with salivary gland tumors was considerably higher in comparison to healthy volunteers blood serum. The considerably higher activity of HEX, HEX-A, GLU, GAL, MAN, FUC and descending trend of activity of HEX-B were noticed in saliva of patients with salivary gland tumors in comparison to healthy volunteers. The assessment of HEX in blood serum and saliva of patients with salivary gland tumor can be possibly used in diagnostics and monitoring of salivary glands tumors.     

Septins enforce morphogenetic events during sexual reproduction and contribute to virulence of Cryptococcus neoformans

Septins are conserved, cytoskeletal GTPases that contribute to cytokinesis, exocytosis, cell surface organization and vesicle fusion by mechanisms that are poorly understood. Roles of septins in morphogenesis and virulence of a human pathogen and basidiomycetous yeast Cryptococcus neoformans were investigated. In contrast to a well‐established paradigm in S. cerevisiae, Cdc3 and Cdc12 septin homologues are dispensable for growth in C. neoformans yeast cells at 24°C but are essential at 37°C. In a bilateral cross between septin mutants, cells fuse but the resulting hyphae exhibit morphological abnormalities, including lack of properly fused specialized clamp cells and failure to produce spores. Interestingly, post‐mating hyphae of the septin mutants have a defect in nuclear distribution. Thus, septins are essential for the development of spores, clamp cell fusion and also play a specific role in nuclear dynamics in hyphae. In the post‐mating hyphae the septins localize to discrete sites in clamp connections, to the septa and the bases of the initial emerging spores. Strains lacking CDC3 or CDC12 exhibit significantly reduced virulence in a Galleria mellonella model of infection. Thus, C. neoformans septins are vital to morphology of the hyphae and contribute to virulence.