Two C-terminal ankyrin repeats form the minimal stable unit of the ankyrin repeat protein p18INK4c

Ankyrin repeat proteins (ARPs) appear to be abundant in organisms from all phyla, and play critical regulatory roles, mediating specific interactions with target biomolecules and thus ordering the sequence of events in diverse cellular processes. ARPs possess a non-globular scaffold consisting of repeating motifs named ankyrin (ANK) repeats, which stack on each other. The modular architecture of ARPs provides a new paradigm for understanding protein stability and folding mechanisms. In the present study, the stability of various C-terminal fragments of the ARP p18^INK4c was investigated by all-atomic 450 ns molecular dynamics (MD) simulations in explicit water solvent. Only motifs with at least two ANK repeats made stable systems in the available timescale. All smaller fragments were unstable, readily losing their native fold and α-helical content. Since each non-terminal ANK repeat has two hydrophobic sides, we may hypothesize that at least one hydrophobic side must be fully covered and shielded from the water as a necessary, but not sufficient, condition to maintain ANK repeat stability. Consequently, at least two ANK repeats are required to make a stable ARP. Figure Structure of the p18INK4c protein (PDB entry 1IHB, chain B), which is a member of the cyclin-dependent kinase inhibitor (INK) tumor suppressor family with five ankyrin (ANK) repeat modules. The figure was generated by PyMol Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Hypertext atlas of fetal and neonatal pathology

Hypertext atlas of fetal and neonatal pathology is a free resource for pregraduate students of medicine, pathologists and other health professionals dealing with prenatal medicine. The atlas can be found at http://www.muni.cz/atlases. The access is restricted to registered users. Concise texts summarize the gross and microscopic pathology, etiology, and clinical signs of both common and rare fetal and neonatal conditions. The texts are illustrated with over 300 images that are accompanied by short comments. The atlas offers histological pictures of high quality. Virtual microscope interface is used to access the high-resolution histological images. Fetal ultrasound video clips are included. Case studies integrate clinical history, prenatal ultrasonographic examination, gross pathology and histological features. The atlas is available in English (and Czech) and equipped with an active index. The atlas is suitable both for medical students and pathologists as a teaching and reference tool. The atlas is going to be further expanded while keeping the high quality of the images.     

Successful use of olanzapine in adolescent monozygotic twins with catatonic schizophrenia resistant to electroconvulsive therapy: case report

We describe a case of monozygotic (MZ) male twins (14.6 years old) who suffered from a severe form of catatonic schizophrenia. On admission, the principal symptoms of the brothers were stupor, mutism, catatonic posturing, rigidity, negativism, and refusal of food and liquids. They were treated with electroconvulsive therapy (ECT) with no effect (twin A) and almost no effect (twin B). Both twins improved with initiation of olanzapine therapy. Twin B showed a marked improvement by week 2 on a dose of 10 mg daily (qd). Improvement in twin A was seen by week 4 on a dose of 15 mg qd. Twin B was discharged after 8 weeks and twin A after 11 weeks of olanzapine treatment. This appears to be the first report on concordant positive responses to olanzapine in MZ twins with catatonic schizophrenia, as well as, the first report on concordant resistance to ECT.     

Sexual Cannibalism in the Brown Widow Spider (Latrodectus geometricus)

Sexual cannibalism may represent an extreme form of male monogamy. According to this view, males gain reproductive success by sacrificing themselves to females. We studied the occurrence and timing of sexual cannibalism in the brown widow spider Latrodectus geometricus and compared male courtship and mating behavior with virgin and with previously mated females. We found that events of sexual cannibalism are frequent, that they occur during copulation and that males initiate cannibalism by placing the abdomen in front of the female’s mouth‐parts during copulation (somersault behavior). Both the somersaults and mating occurred more frequently with virgins than with previously mated females. Our results support the hypothesis that sexual cannibalism is a male strategy in this species. The somersault behavior was previously known only from the redback spider, Latrodectus hasselti. It is as yet unknown whether self‐sacrifice has evolved more than once in this genus.     

Animal reproduction biotechnology in Poland

The key research areas of the Department are: in vitro production of embryos, embryo cryopreservation, animal transgenesis, cloning, cytometric semen sexing and evaluation. Research has been focused on the in vitro production of animal embryos, including the development of complex methods for oocyte maturation, fertilization and embryo culture. Moreover, experiments on long-term culturing of late preantral and early antral bovine ovarian follicles have been developed. Studies on the cloning of genetically modified pigs with "humanized" immunological systems have been undertaken. A cloned goat was produced from oocytes reconstructed with adult dermal fibroblast cells. The novel technique of rabbit chimeric cloning for the production of transgenic animals was applied; additionally, the recipient-donor-cell relationship in the preimplantation developmental competences of feline nuclear transfer embryos has been studied. Regarding transgenic animal projects, gene constructs containing growth hormone genes connected to the mMt promoter were used. Modifications of milk composition gene constructs with tissue-specific promoters were performed. Moreover, pigs for xenotransplantation and animal models of human vascular diseases have been produced. Over the last 15 years, our flow cytometry research group has focused its work on new methods for sperm quality assessment and sex regulation. In the 1970s, our team initiated studies on embryo cryopreservation. As a result of vitrification experiments, the world's first rabbits and sheep produced via the transfer of vitrified embryos were born.