Biology and regulation of ectoplasmic specialization, an atypical adherens junction type, in the testis

Anchoring junctions are cell adhesion apparatus present in all epithelia and endothelia. They are found at the cell-cell interface (adherens junction (AJ) and desmosome) and cell-matrix interface (focal contact and hemidesmosome). In this review, we focus our discussion on AJ in particular the dynamic changes and regulation of this junction type in normal epithelia using testis as a model. There are extensive restructuring of AJ (e.g., ectoplasmic specialization, ES, a testis-specific AJ) at the Sertoli-Sertoli cell interface (basal ES) and Sertoli-elongating spermatid interface (apical ES) during the seminiferous epithelial cycle of spermatogenesis to facilitate the migration of developing germ cells across the seminiferous epithelium. Furthermore, recent findings have shown that ES also confers cell orientation and polarity in the seminiferous epithelium, illustrating that some of the functions initially ascribed to tight junctions (TJ), such as conferring cell polarity, are also part of the inherent properties of the AJ (e.g., apical ES) in the testis. The biology and regulation based on recent studies in the testis are of interest to cell biologists in the field, in particular their regulation, which perhaps is applicable to tumorigenesis.     

Diversity and distribution of reptiles in Romania

The reptile fauna of Romania comprises 23 species, out of which 12 species reach here the limit of their geographic range. We compiled and updated a national database of the reptile species occurrences from a variety of sources including our own field surveys, personal communication from specialists, museum collections and the scientific literature. The occurrence records were georeferenced and stored in a geodatabase for additional analysis of their spatial patterns. The spatial analysis revealed a biased sampling effort concentrated in various protected areas, and deficient in the vast agricultural areas of the southern part of Romania. The patterns of species richness showed a higher number of species in the warmer and drier regions, and a relatively low number of species in the rest of the country. Our database provides a starting point for further analyses, and represents a reliable tool for drafting conservation plans.     

The Effect of Antenatal Depression and Selective Serotonin Reuptake Inhibitor Treatment on Nerve Growth Factor Signaling in Human Placenta

Depressive symptoms during pregnancy are common and may have impact on the developing child. Selective serotonin reuptake inhibitors (SSRIs) are the most prescribed antidepressant treatment, but unfortunately, these treatments can also negatively affect the behavioral development and health of a child during pregnancy. In addition, serotonin (5-HT) exerts neurotrophic actions with thus far not fully known effects in the offspring. The neurotrophic growth factor (NGF) is involved in neuronal cell survival and differentiation, and altered placenta levels have been found to increase the risk for pregnancy complications, similar to those found in women treated with SSRIs. We therefore investigated whether the NGF signaling pathway was altered in the placenta from women treated with SSRIs (n = 12) and compared them with placenta from depressed (n = 12) and healthy mothers (n = 12). Results from immunohistochemical stainings revealed that placental NGF protein levels of SSRI-treated women were increased in both trophoblasts and endothelial cells compared with depressed and control women. In addition, downstream of the NGF receptor TrkA, increased levels of the signaling proteins ROCK2 and phosphorylated Raf-1 were found in stromal cells and a tendency towards increased levels of ROCK2 in trophoblasts and endothelial cells in SSRI-treated women when compared to healthy controls. SSRI-treated women also displayed increased levels of phosphorylated ROCK2 in all placental cell types studied in comparison with depressed and control women. Interestingly, in placental endothelial cells from depressed women, NGF levels were significantly lower compared to control women, but ROCK2 levels were increased compared with control and SSRI-treated women. Taken together, these results show that the NGF signaling and downstream pathways in the placenta are affected by SSRI treatment and/or antenatal depression. This might lead to an altered placental function, although the clinical relevance of our findings still needs to be investigated.     

Effect of arm-shoulder fatigue on carpenters at work

The purpose of the study was to analyse the effect of arm-shoulder fatigue on manual performance. Ten experienced carpenters performed three standardized tasks (nailing, sawing and screwing). Electromyographic activity was recorded from six arm-shoulder muscles and the performances were video-filmed. After 45 min of standardized arm-cranking (arm-shoulder-fatiguing exercise of approximately 70%-80% maximal oxygen consumption), the tasks were repeated. The number of work movements and the time taken for each task were recorded and the quality of the work performed was compared. After the fatiguing exercise, only nailing was perceived as being harder and more mistakes were made during nailing and sawing. Movement performance was not influenced during nailing but was slightly slower during sawing and faster during screwing. However, there were increased mean EMG amplitudes in the upper trapezius and biceps muscles during nailing, in the upper trapezius, anterior deltoid and infraspinatus muscles during sawing and in the anterior deltoid muscle during screwing. Of the muscles studied the upper trapezius and anterior deltoid muscles increased their activity most after the arm-shoulder-fatiguing exercise.     

Diazepam metabolism by multiple forms of cytochrome P-450 in rat liver microsomes

The synthesis of pharmacologically active diazepam metabolites (oxazepam, 4-hydroxydiazepam, N-demethyldiazepam) in liver microsomes of intact and phenobarbital-, 3-methylcholanthrene- and dexamethasone-induced male and female Wistar rats as well as in a reconstituted system with isolated forms of cytochrome P-450 (P-450a, P-450b, P-450c, P-450d and P-450k according to the Ryan nomenclature) was studied. Marked sex-dependent differences in the rates of diazepam metabolism in liver microsomes of intact and induced animals were revealed. The changes in the spectrum of diazepam metabolites in liver microsomes of induced rats (as compared to control animals) were revealed. In a reconstituted system only phenobarbital-induced cytochromes P-450b and P-450k were found to be active participants of diazepam N-demethylation; none of the isoenzymes tested were shown to be involved in diazepam hydroxylation.     

The cystine knot of a squash-type protease inhibitor as a structural scaffold for Escherichia coli cell surface display of conformationally constrained peptides.

The Ecballium elaterium trypsin inhibitor II (EETI-II), a member of the squash family of protease inhibitors, is composed of 28 amino acid residues and is a potent inhibitor of trypsin. Its compact structure is defined by a triple-stranded antiparallel beta-sheet, which is held together by three intramolecular disulfide bonds forming a cystine knot. In order to explore the potential of the EETI-II peptide to serve as a structural scaffold for the presentation of randomized oligopeptides, we constructed two EETI-II derivatives, where the six-residue inhibitor loop was replaced by a 13-residue epitope of Sendai virus L-protein and by a 17-residue epitope from human bone Gla-protein. EETI-II and derived variants were produced via fusion to maltose binding protein MalE. By secretion of the fusion into the periplasmic space, fully oxidized and correctly folded EETI-II was obtained in high yield. EETI-II and derived variants could be presented on the Escherichia coli outer membrane by fusion to truncated Lpp'-OmpA', which comprises the first nine residues of mature lipoprotein plus the membrane spanning beta-strand from residues 46-66 of OmpA protein. Gene expression was under control of the strong and tightly regulated tetA promoter/operator. Cell viability was found to be drastically reduced by high level expression of Lpp'-OmpA'-EETI-II fusion protein. To restore cell viability, net accumulation of fusion protein in the outer membrane was reduced to a tolerable level by introduction of an amber codon at position 9 of the lpp' sequence and utilizing an amber suppressor strain as expression host. Cells expressing EETI-II variants containing an epitope were shown to be surface labeled with the respective monoclonal antibody by indirect immunofluorescence corroborating the cell surface exposure of the epitope sequences embedded in the EETI-II cystine knot scaffold. Cells displaying a particular epitope sequence could be enriched 10(7)-fold by combining magnetic cell sorting with fluorescence-activated cell sorting. These results demonstrate that E.coli cell surface display of conformationally constrained peptides tethered to the EETI-II cystine knot scaffold has the potential to become an effective technique for the rapid isolation of small peptide molecules from combinatorial libraries that bind with high affinity to acceptor molecules.     

Statistical Analysis of Sleep Spindle Occurrences

Spindles - a hallmark of stage II sleep - are a transient oscillatory phenomenon in the EEG believed to reflect thalamocortical activity contributing to unresponsiveness during sleep. Currently spindles are often classified into two classes: fast spindles, with a frequency of around 14 Hz, occurring in the centro-parietal region; and slow spindles, with a frequency of around 12 Hz, prevalent in the frontal region. Here we aim to establish whether the spindle generation process also exhibits spatial heterogeneity. Electroencephalographic recordings from 20 subjects were automatically scanned to detect spindles and the time occurrences of spindles were used for statistical analysis. Gamma distribution parameters were fit to each inter-spindle interval distribution, and a modified Wald-Wolfowitz lag-1 correlation test was applied. Results indicate that not all spindles are generated by the same statistical process, but this dissociation is not spindle-type specific. Although this dissociation is not topographically specific, a single generator for all spindle types appears unlikely.     

Kemantane pharmacokinetics in rats

Pharmacokinetics of novel immunostimulating drug kamantane was studied by using gas-liquid chromatography in experiments on rats. It was found that kemantane biotransformed rapidly after oral administration with the forming of active metabolite. Kemantane and its metabolites are distributed rapidly from the blood to organs. The drug is eliminated from the organism of rats as metabolite.     

Activation of endogenous lipid peroxidation in the brain in oxidation stress caused by administration of iron and its prevention by vitamin E

Looking for an appropriate model of accelerated aging in vivo we investigated the content of endogenous products of lipid peroxidation (LP) in the rat brain after single or 4 day-lasting intramuscular injection of complex-bind iron (ferum Hausman, 50 mg/kg body weight) like promoter of LP. We found that the single administration of this iron complex fails to induce endogenous LP; after 4 day-application of iron we observed significant increase in content of primary (lipid peroxides) and final (fluorescent) products of LP. Iron-promoted activation of endogenous LP could be abolished by animal pretreatment with the natural antioxidant alpha-tocopherol. The calcium antagonist nifedipine didn't affect the content of endogenous LP products neither alone nor in combination with alpha-tocopherol.