Accelerated Evolution of the Prdm9 Speciation Gene across Diverse Metazoan Taxa

The onset of prezygotic and postzygotic barriers to gene flow between populations is a hallmark of speciation. One of the earliest postzygotic isolating barriers to arise between incipient species is the sterility of the heterogametic sex in interspecies' hybrids. Four genes that underlie hybrid sterility have been identified in animals: Odysseus, JYalpha, and Overdrive in Drosophila and Prdm9 (Meisetz) in mice. Mouse Prdm9 encodes a protein with a KRAB motif, a histone methyltransferase domain and several zinc fingers. The difference of a single zinc finger distinguishes Prdm9 alleles that cause hybrid sterility from those that do not. We find that concerted evolution and positive selection have rapidly altered the number and sequence of Prdm9 zinc fingers across 13 rodent genomes. The patterns of positive selection in Prdm9 zinc fingers imply that rapid evolution has acted on the interface between the Prdm9 protein and the DNA sequences to which it binds. Similar patterns are apparent for Prdm9 zinc fingers for diverse metazoans, including primates. Indeed, allelic variation at the DNA–binding positions of human PRDM9 zinc fingers show significant association with decreased risk of infertility. Prdm9 thus plays a role in determining male sterility both between species (mouse) and within species (human). The recurrent episodes of positive selection acting on Prdm9 suggest that the DNA sequences to which it binds must also be evolving rapidly. Our findings do not identify the nature of the underlying DNA sequences, but argue against the proposed role of Prdm9 as an essential transcription factor in mouse meiosis. We propose a hypothetical model in which incompatibilities between Prdm9-binding specificity and satellite DNAs provide the molecular basis for Prdm9-mediated hybrid sterility. We suggest that Prdm9 should be investigated as a candidate gene in other instances of hybrid sterility in metazoans

Cognitive behavioral therapy in pharmacoresistant obsessive–compulsive disorder

Jana Vyskocilova,1 Jan Prasko,2 Jiri Sipek3 1Faculty of Humanities, Charles University in Prague, Prague, 2Department of Psychiatry, Faculty of Medicine and Dentistry, Palacky University Olomouc, University Hospital Olomouc, Olomouc, 3Department of Psychology, Faculty of Arts, Charles University in Prague, Prague, Czech Republic Background: The aim of the study was to determine whether patients with obsessive–compulsive disorder (OCD) resistant to drug therapy may improve their condition using intensive, systematic cognitive behavioral therapy (CBT) lasting for 6 weeks, and whether it is possible to predict the therapeutic effect using demographic, clinical, and selected psychological characteristics at baseline. Methods: Sixty-six OCD patients were included in the study, of which 57 completed the program. The diagnosis was confirmed using the structured Mini International Neuropsychiatric Interview. Patients were rated using the objective and subjective forms of the Yale–Brown Obsessive Compulsive Scale, objective and subjective forms of the Clinical Global Impression, Beck Anxiety Inventory, Beck Depression Inventory, Dissociative Experiences Scale, 20-item Somatoform Dissociation Questionnaire, and the Sheehan Disability Scale before their treatment, and with subjective Yale–Brown Obsessive Compulsive Scale, objective and subjective Clinical Global Impression, Beck Anxiety Inventory, and Beck Depression Inventory at the end of the treatment. Patients were treated with antidepressants and daily intensive group CBT for the 6-week period. Results: During the 6-week intensive CBT program in combination with pharmacotherapy, there was a significant improvement in patients suffering from OCD resistant to drug treatment. There were statistically significantly decrease in the scores assessing the severity of OCD symptoms, anxiety, and depressive feelings. A lower treatment effect was achieved specifically in patients who 1) showed fewer OCD themes in symptomatology, 2) showed a higher level of somatoform dissociation, 3) had poor insight, and 4) had a higher initial level of overall severity of the disorder. Remission of the disorder was more likely in patients who had 1) good insight, 2) a lower initial level of anxiety, and 3) no comorbid depressive disorder. Keywords: obsessive–compulsive disorder, treatment, cognitive behavioral therapy, treatment resistance, treatment efficacy, predictor

Calcination of Marls to Produce Roman Cement

noMarls were identified from a range of European sources and assessed for their Cementation Index, as proposed by Eckel. Two were selected for calcination in a laboratory kiln; one from Folwark in Poland (CI 1.75) and one from Lillienfeld in Austria (CI 2.03). Analysis of historical documents, while not revealing precise kiln conditions, does suggest that they were such as not to yield complete decarbonation of the calcite. Consequently, a series of calcinations was undertaken in which the peak temperature control of the kiln was set in the range 730°C to 1100°C, with residence times in the range 150 to 1250 min. The airflow through the kiln was sufficient to maintain a minimum oxygen content of at least 12 %. The resulting clinker was ground to comply with the 19th century Austrian Norme. Pastes were produced at w/c = 0.65 and assessed for setting time and strength development (6 h to 1 year). Both parameters were highly dependent upon calcination conditions with both ¿low¿ and ¿high¿ calcinations producing slower setting and slower strength development than intermediate conditions. Two strength development profiles were identified; one being the expected continuous increase of strength, albeit with a declining rate of increase with time, while the other showed a three-step sequence of high initial strength, a dormant period which could last for many weeks and a final increase in strength to an age of one year. The cements were compared using X-ray diffraction (XRD). Considerable variation in the composition was noted and related to the calcination conditions. Of particular interest is the formation of both ¿'-belite and ß-belite under differing calcination conditions. Clinker particles were also compared using the SEM in back-scattered electron imaging mode and the development of morphology observed

Hydration processes in pastes of Roman and American Natural Cements.

NoHydration of five Roman and American natural cements was analyzed using X-ray diffraction, mercury intrusion porosimetry, and scanning electron microscopy of cement pastes. Two cements were prepared in the laboratory by burning marls from geological sources in Poland (Folwark) and Austria (Lilienfeld). The selection of raw materials and burning conditions were optimized so that the hydraulic nature and appearance of the final burnt materials matched as closely as possible historic Roman cements widely used in the 19th and the beginning of the 20th centuries in Europe to decorate buildings. Three other cements are produced commercially: quick setting Prompt cement from Vicat, France, and Rosendale cements from Edison Coatings Inc., USA. The hydration of the cements studied was shown to comprise two distinct stages. The immediate setting and early strength is due to the formation of calcium aluminum oxide carbonate (or sulfate) hydroxide hydrates. The development of long-term strength is brought about by the formation of calcium silicate hydrates. Similarities and differences between the individual cements are discussed