Taurine as a water structure breaker and protein stabilizer.

The enhancing effect on the water structure has been confirmed for most of the osmolytes exhibiting both stabilizing and destabilizing properties in regard to proteins. The presented work concerns osmolytes, which should be classified as "structure breaking" solutes: taurine and N,N,N-trimethyltaurine (TMT). Here, we combine FTIR spectroscopy, DSC calorimetry and DFT calculations to gain an insight into the interactions between osmolytes and two proteins: lysozyme and ubiquitin. Despite high structural similarity, both osmolytes exert different influence on protein stability: taurine is a stabilizer, TMT is a denaturant. We show also that taurine amino group interacts directly with the side chains of proteins, whereas TMT does not interact with proteins at all. Although two solutes weaken on average the structure of the surrounding water, their hydration spheres are different. Taurine is surrounded by two populations of water molecules: bonded with weak H-bonds around sulfonate group, and strongly bonded around amino group. The strong hydrogen-bonded network of water molecules around the amino group of taurine further improves properties of enhanced protein hydration sphere and stabilizes the native protein form. Direct interactions of this group with surface side chains provide a proper orientation of taurine and prevents the [Formula: see text] group from negative influence. The weakened [Formula: see text] hydration sphere of TMT breaks up the hydrogen-bonded network of water around the protein and destabilizes it. However, TMT at low concentration stabilize both proteins to a small extent. This effect can be attributed to an actual osmophobic effect which is overcome if the concentration increases.

Correction: Are stabilizing osmolytes preferentially excluded from the protein surface? FTIR and MD studies.

Correction for 'Are stabilizing osmolytes preferentially excluded from the protein surface? FTIR and MD studies' by P. Bruzdziak et al., Phys. Chem. Chem. Phys., 2015, 17, 23155-23164.

Are stabilizing osmolytes preferentially excluded from the protein surface? FTIR and MD studies.

Interactions between osmolytes and hen egg white lysozyme in aqueous solutions were studied by means of FTIR spectroscopy and molecular dynamics. A combination of difference spectra method and chemometric analysis of spectroscopic data was used to determine the number of osmolyte molecules interacting with the protein, and the preferential interaction coefficient in presented systems. Both osmolytes -l-proline and trimethylamine-N-oxide (TMAO) - belong to a group of stabilizing osmolytes, and according to the preferential exclusion/hydration hypothesis, both should be excluded from the vicinity of the protein backbone and surface. We provide experimental and computational evidence that although TMAO behaves according to the hypothesis, proline does not. Our results suggest that preferential exclusion is not a universal property of stabilizing osmolytes.

[Morphologic examination of ovaries and liver after repeated administration of cyclophosphamide in therapeutic low doses to immature experimental rodents in various stages of individual maturity]. / Morfologiczna ocena jajnika i watroby po stosowaniu wielokrotnych terapeutycznych dawek cyklofosfamidu u niedojrzalych gryzoni doswiadczalnych w róznych okresach rozwoju osobniczego.

Liver and ovarian tissue samples of the immature healthy Wistar rats were examined histologically after administration of the repeated low doses of cyclophosphamide. The youngest experimental group was at the age of 7/14 days. Morphologic examination involved histochemical, histoenzymatic, morphometric and ultrastructural techniques. The observed changes in the liver tissue were minimal and totally reversible at time of animals maturity. Pathomorphological changes in ovaries were more evident and complex, concerning all structures of the gland. The dominant features of the damage included the disturbances of the physiological morphological maturation and the widespread hyperluteinization of all structures. In spite of the morphological changes, the activity of the hydroxysteroid dehydrogenases in ovaries remained unchanged.

[Histoenzymatic study of postnatal development of the rat ovary, follicular atresia and interstitial gland]. / Histoenzymatyczna ocena postnatalnego rozwoju jajnika szczura, powstawanie pecherzyków atretycznych i gruczolu sródmiazszowego.

In our experiment, we investigated histoenzymatic activity od postnatal development of rat ovary, specially the main metabolic process--steroidogenesis. We noticed, that during early folliculogenesis great amount of follicles are eliminated by atresia. Atresia also plays very important role in forming of interstitial gland. Interstitial gland which is found in ovary of 14 days old rat ovaries, morphologically and enzymatically differs from the structure observed on older animals. We concluded, that ovary of 14 days old rat is not developed but ovary of 21 days old rat seems to be morphologically and histochemically well developed.

[Morphological evaluation of postnatal development of the rat ovary]. / Morfologiczna ocena postnatalnego rozwoju jajnika szczura.

Follicular development represents one of the essential functions of the ovary. It was done a lot of various classifications including kinetics or morphometry of growing follicles. All these experiments were carried on adult animals and so very little was known about developing follicles in youngs. In the view of this, we decided to investigate the postnatal development of rat ovary. Ovaries from rats between 14-84 days were examined; our own modification was used for classification of follicles, the number of each type of follicles and their diameter was counted, the number of granulosa cells in small growing follicles was noted and diameter of luteal cell and its elements in luteal body in which ovulation took place, were described.

[Histochemical evaluation of postnatal development of the rat ovary]. / Histochemiczna ocena postnatalnego rozwoju jajnika szczura.

Many morphological studies were carried on the ovarian development and only few on histochemistry of this process. Our previous experiments showed, there was a critical period for developing ovary between 20-49 days of life. We decided to clear what kind of biosynthesis was playing essential role during this period and what functions had each structure of the ovary. The qualitative studies of following enzymes: succinic, isocitric lactate, glucoso-6-phosphate, 3-beta and 17-beta- hydroksysteroid dehydrogenases were done. Proteins, nucleic acids and lipids were also examined. In general, total activity of tested enzymes didn't varied much, but great differences between activity of ovarian elements were observed. The interstitial gland was much more active than any other structure, mainly the enzymatic activity connected with biosynthesis of gestagens and androgens was noted. Theca was also very active but less than interstitial gland, besides it seemed to have no possibility to synthetise androgens because of 17-beta- hydroksysteroid dehydrogenase absence.

Chronic pretrigeminal kitten.

In two kittens the brainstem was transected at the pretrigeminal level at the age of 11 days. The kittens were then observed for 79 and 51 days. As compared with control littermates, the weight of the transected brains was reduced by about 25 percent. As compared with the controls transected at the age of 2 or 3 months, as well as with previously described cats transected at adult age, the function of the caudal part of the kittens was much better. They showed some locomotion, drank and ate when the mouth was placed in contact with the milk or meat, rejected untasty food and showed satiation. On the other hand, the function of the isolated cerebrum was reduced as shown by only abortive ocular and EEG responses to visual stimuli. Thus, the pretrigeminal transection performed at an early period of life improves the development of the caudal part of preparation, but impairs that of the isolated cerebrum.