Brain mast cells and therapeutic potential of vasoactive intestinal peptide in a Parkinson's disease model in rats: brain microdialysis, behavior, and microscopy

In the present study, the effect of systemically administered vasoactive intestinal peptide (VIP) (25 ng/kg i.p.) was investigated on drug-induced rotational behavior, extra-cellular dopamine levels and histology of corpus striatum in a 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease. After 15 days of 6-OHDA lesion, apomorphine-induced (0.05 mg/kg s.c.) rotational behavior of the animals significantly increased and extra-cellular dopamine levels of corpus striatum were significantly reduced. VIP reversed the rotational deficits but did not alter the decrease in striatal dopamine levels. On the other hand, histological data indicate that VIP significantly reduced neuronal death and demyelination. Electron microscopic appearance of mast cells showed ultra-structural variety between VIP-treated and 6-OHDA lesioned groups. VIP activates mast cells without any evidence of typical exocytosis, and possibly mast cells could participate in neuroprotection. Our results suggest that systemically administered VIP can attenuate the motor response changes, neuronal cell death, and myelin sheet loss characteristically associated with 12 microg 6-OHDA administration into the rat striatum. Brain mast cells seem to participate in neuronal protection. Possibly, protective cues could be produced by brain mast cells.     

Dynamics of brain rhythmic and evoked potentials

In this study, the simultaneously recorded and selectively averaged evoked potentials in some of the structures of the auditory pathway (acoustical cortex, medial geniculate nucleus, inferior colliculus), in the reticular formation and the hippocampus of the awake cat as well as the simultaneous amplitude frequency characteristics of these structures are given. The power spectral density functions computed from the simultaneously recorded spontaneous activity of these structures are also presented. Using these results, the following analyses are accomplished: (1) determination of the dynamics of potentials simultaneously obtained from various brain structures, in order to evaluate the common features of their system characteristics; (2) determination of the relationship (or interactions) between rhythmic activity and evoked potentials of the brain, and (3) elaboration of a working hypothesis for the dynamics of potentials of the brain. Some suggestions and comments are also made for investigators working toward theories or dynamic models of signal transmission in the brain.     

Determination of Growth and Glycerol Production Kinetics of a Wine Yeast Strain Saccharomyces cerevisiae Kalecik 1 in Different Substrate Media

Summary Glycerol has been known as an important by-product of wine fermentations improving the sensory quality of wine. This study was carried out with an endogenic wine yeast strain Saccharomyces cerevisiae Kalecik 1. The kinetics of growth and glycerol biosynthesis were analysed at various initial concentrations of glucose, fructose, and sucrose in a batch system. Depending on the determined values of Monod constants, glucose (K_s = 28.09 g/l) was found as the most suitable substrate for the yeast growth. Initial glucose, fructose and sucrose concentrations necessary for maximum specific yeast growth rate were determined as 175 g, 100 l, and 200 g/l, respectively. The yeast produced glycerol at very high concentrations in fructose medium. Fructose was determined as the most suitable substrate for glycerol production while the strain showed low tendency to use it for growth. S. cerevisiae Kalecik 1 could not produce glycerol below 200 g/l initial sucrose concentration. When natural white grape juice was used as fermentation medium, maximum glycerol concentration and dry weight of the yeast were determined as 9.3 g/l and 11.8 g/l, respectively.     

Bacterial tail anchors can target to the mitochondrial outer membrane

Background

During the generation and evolution of the eukaryotic cell, a proteobacterial endosymbiont was re-fashioned into the mitochondrion, an organelle that appears to have been present in the ancestor of all present-day eukaryotes. Mitochondria harbor proteomes derived from coding information located both inside and outside the organelle, and the rate-limiting step toward the formation of eukaryotic cells may have been development of an import apparatus allowing protein entry to mitochondria. Currently, a widely conserved translocon allows proteins to pass from the cytosol into mitochondria, but how proteins encoded outside of mitochondria were first directed to these organelles at the dawn of eukaryogenesis is not clear. Because several proteins targeted by a carboxyl-terminal tail anchor (TA) appear to have the ability to insert spontaneously into the mitochondrial outer membrane (OM), it is possible that self-inserting, tail-anchored polypeptides obtained from bacteria might have formed the first gate allowing proteins to access mitochondria from the cytosol.

Results

Here, we tested whether bacterial TAs are capable of targeting to mitochondria. In a survey of proteins encoded by the proteobacterium Escherichia coli, predicted TA sequences were directed to specific subcellular locations within the yeast Saccharomyces cerevisiae. Importantly, TAs obtained from DUF883 family members ElaB and YqjD were abundantly localized to and inserted at the mitochondrial OM.

Conclusions

Our results support the notion that eukaryotic cells are able to utilize membrane-targeting signals present in bacterial proteins obtained by lateral gene transfer, and our findings make plausible a model in which mitochondrial protein translocation was first driven by tail-anchored proteins.

Reviewers

This article was reviewed by Michael Ryan and Thomas Simmen.

     

The investigation of the secondary structure propensities and free-energy landscapes of peptide ligands by replica exchange molecular dynamics simulations

The conformational states of two peptide sequences that bind to staphylococcal enterotoxin B are sampled by replica exchange molecular dynamic (REMD) simulations in explicit water. REMD simulations were treated with 52 replicas in the range of 280–501 K for both peptides. The conformational ensembles of both peptides are dominated by random coil, bend and turn structures with a small amount of helical structures for each temperature. In addition, while an insignificant presence of β-bridge structures were observed for both peptides, the β-sheet structure was observed only for peptide 3. The results obtained from simulations at 300 K are consistent with the experimental results obtained from circular dichroism spectroscopy. From the analysis of REMD results, we also calculated hydrophobic and hydrophilic solvent accessible surface areas for both peptides, and it was observed that the hydrophobic segments of the peptides tend to form bend or turn structures. Moreover, the free-energy landscapes of both peptides were obtained by principal component analysis to understand how the secondary structural properties change according to their complex space. From the free-energy analysis, we have found several minima for both peptides at decreased temperature. For these obvious minima of both peptides, it was observed that the random coil, bend and turn structures are still dominant and the helix, β-bridge or β-sheet structures can appear or disappear with respect to minima. On the other hand, when we compare the results of REMD with conventional MD simulations for these peptides, the configurations of peptide 3 might be trapped in energy minima during the conventional MD simulations. Hence, it can be said that the REMD simulations have provided a sufficiently high sampling efficiency.     

The value of ultrasonography alone in screening surveys of cystic echinococcosis in children in Turkey

A total of 1205 primary school children were examined for cystic echinococcosis in five villages of Manisa, Turkey, to evaluate the efficacy of diagnostic methods of this infection in community-based screening surveys. Six hundred and thirty children from three villages, examined by a portable ultrasound scanner, chest microfilm and serological methods (ELISA, indirect hemagglutination) in our previous study, were designated as Study Group 1; and 575 children, from two adjacent villages, examined by ultrasonography alone in the present study, were designated as Study Group 2. In Study Group 1, hepatic cystic echinococcosis was detected in two cases (0.3%) by ultrasonography, while 43 (8.9%) and 49 (10.1%) cases were found to be positive for cystic echinococcosis by ELISA and indirect hemagglutination, respectively. Three of 575 children (0.5%) were diagnosed with cystic echinococcosis (two hepatic and one renal involvement) by ultrasonography alone in Study Group 2; and lung lesions were later detected in both cases with liver involvement by chest radiography.

Our results suggested that serological tests may be beneficial in suspected cases for confirmation and differential diagnosis, but have some drawbacks, such as discrepancy in results and high false seropositivity rates. Chest microfilm is not easy in field studies and exposure to X-ray is undesirable. As a reliable, simple, inexpensive and rapid technique, ultrasonography alone is recommended to be used in community-based screening surveys for cystic echinococcosis with confirmatory tests for suspected cases found during the screening program.     

Thanetian gastropods from the Mesopotamian high folded zone in northern Iraq

An assemblage of gastropods from the Thanetian of the Kolosh Formation from the Zakho region in northern Iraq is documented for the first time. The ten species represent the families Campanilidae Douvillé 1904, Potamididae H. & A. Adams 1854, Batillariidae Thiele 1929, Thiaridae Gill 1871, Pachychilidae Fischer & Crosse 1892, Cerithiidae Fleming 1822 and Pseudolividae de Gregorio 1880, suggesting a littoral to shallow sublittoral depositional environment. Six of the species are new and five are formally described as new species. At least seven species are also known from the Thanetian and/or Early Ypresian of the Ankara region in Turkey. Only a single species occurs also in the Paleocene of the Paris Basin. No relation to Paleocene and Eocene faunas of Pakistan and India is detectable. This points to a considerably bioprovincialism along the northern coast of the Tethys. Consequently we suppose the existence of an Anatolian Province in the Thanetian/Ypresian Mediterranean Region of the Tethys Realm, represented by rather homogeneous mollusc faunas from western Turkey and northern Iraq. Campanile zakhoense nov. sp., Pyrazopsis hexagonpyramidalis nov. sp., Pachymelania islamogluae nov. sp., “Faunus” dominicii nov. sp. and Pseudoaluco mesopotamicus nov. sp. are introduced as new species. Varicipotamides Pacaud & Harzhauser nov. nom. is proposed as the replacement name for Exechestoma Cossmann (1889) non Brandt (1837).     

Luteinizing hormone releasing hormone increases proliferation of meningioma cells in vitro

The fact that meningioma shows at least a 2:1 predilection for women over men is considered to be due to endocrinological and paracrine regulation of the development of this tumour. The presence of receptors for the luteinizing hormone releasing hormone (LHRH) in gynaecological cancer permits the use of LHRH agonistic or antagonistic analogues with a direct effect or by the gonado-pituitary axis suppression in the treatment of these tumours. Therefore, the effect of LHRH on meningioma cells is tested in this study. Meningioma cells from three female patients were cultured and LHRH (50 ng/ml) was added to the growth medium daily, for fourteen days. At the end of this period the cells were counted by means of a Coulter Counter. The stimulating effects of LHRH on the increase of the amount of cells in the meningioma monolayer culture were 146% (p < 0.01), 134% (p < 0.05) and 141% (p < 0.05) of the control, respectively, for the three patients.     

Enzymatic determination of zinc in vegetables using apocarbonic anhydrase

A new enzymatic method has been developed to determine trace amounts of Zn2+ in vegetables. The basis of the method is that apocarbonic anhydrase regains its activity in proportion to the concentration of Zn2+ present in solution. Bovine carbonic anhydrase was purified from erythrocyte haemolysate by affinity chromatography and the bound Zn2+ removed by dialysis of purified enzyme against a solution of pyridine-2, 6-dicarboxylic acid. Pure (100%) apoenzyme was obtained. The concentration of Zn2+ in vegetable samples was determined using the enzymatic method and by atomic absorption spectroscopy. Determinations made using the two methods were not significantly different one from another.