Antioxidative effect of the N-stearoylethanolamine in the heart tissue and blood plasma of rats under doxorubicin treatment

The influence of N-stearoylethanolamine on the alterated antioxidant enzyme activity in the heart tissue and blood plasma of rats under the doxorubicin treatment was investigated. It was shown that doxorubicin administration caused the decrease of antioxidant enzymes activity (superoxide dismutase and glutathione peroxidase) in the heart tissue. Administration of the NSE promoted the partial normalization of these enzymes activity. It was shown that doxorubicin treatment caused the increase of the urea and creatinine level in the blood plasma of experimental animals. The NSE administration normalized the level of the urea and did not affect creatinine level.     

MicroRNA expression profiling in neurogenesis of adipose tissue-derived stem cells

Adipose tissue-derived stem cells (ADSCs) are one population of adult stem cells that can self renew and differentiate into multiple lineages. Because of advantages in method and quantity of acquisition, ADSCs are gaining attention as an alternative source of bone marrow mesenchymal stem cells. In this study, we performed microRNA profiling of undifferentiated and of neurally-differentiated ADSCs to identify the responsible microRNAs in neurogenesis using this type of stem cell. MicroRNAs from four different donors were analysed by microarray. Compared to the undifferentiation control, we identified 39–101 microRNAs with more than two-fold higher expression and 3–9 microRNAs with two-fold lower expression. The identified microRNAs were further analysed in terms of gene ontology (GO) in relation with neurogenesis, based on their target mRNAs predicted by computational analysis. This study revealed the specific microRNAs involved in neurogenesis via microRNA microarray, and may provide the basic information for genetic induction of adult stem cell differentiation using microRNAs.     

The effects of n-stearoylethanolamine on the NO-synthase pathway of NO generation in the aorta and heart of streptozotocin-induced diabetic rats

The aim of the presented experiments was to study the influence of suturated NAE--N-stearoylethanolamine (NSE) on the NO synthesis by NO-synthases in aorta and heart tissues of rats with developmental (12-week) streptozotocin-induced (50 mg/kg of body weight) diabetes. Also we evaluated the state of endothelium-dependent relax reactions of aorta smooth muscles. It was shown that the development of diabetes is accompanied with disbalance of NO-synthesis wich consist in inducible NOS (iNOS) activation and inhibition of constitutive NOS (cNOS) and arginase activities. The aorta smooth muscle endothelium-dependent relax reactions were decreased in diabetic rats. The NSE administration to rats with development streptozotocin-induced diabetes resulted in inhibition of iNOS activity and elevation of cNOS and arginase activities in these tissues. Normalization of NO-synthesis under NSE action was accompanied with restoration of aorta smooth muscle endothelium-dependent relax reactions in diabetic rats.     

Differential regulation of sphingomyelin synthesis and catabolism in oligodendrocytes and neurons

Neurons (both primary cultures of 3-day rat hippocampal neurons and embryonic chick neurons) rapidly converted exogenous NBD-sphingomyelin (SM) to NBD-Cer but only slowly converted NBD-Cer to NBD-SM. This was confirmed by demonstrating low in vitro sphingomyelin synthase (SMS) and high sphingomyelinase (SMase) activity in neurons. Similar results were observed in a human neuroblastoma cell line (LA-N-5). In contrast, primary cultures of 3-day-old rat oligodendrocytes only slowly converted NBD-SM to NBD-Cer but rapidly converted NBD-Cer to NBD-SM. This difference was confirmed by high in vitro SMS and low SMase activity in neonatal rat oligodendrocytes. Similar results were observed in a human oligodendroglioma cell line. Mass-Spectrometric analyses confirmed that neurons had a low SM/Cer ratio of (1.5 : 1) whereas oligodendroglia had a high SM/Cer ratio (9 : 1). Differences were also confirmed by [³H]palmitate-labeling of ceramide, which was higher in neurons compared with oligodendrocytes. Stable transfection of human oligodendroglioma cells with neutral SMase, which enhanced the conversion of NBD-SM to NBD-Cer and increased cell death, whereas transfection with SMS1 or SMS2 enhanced conversion of NBD-Cer to NBD-SM and was somewhat protective against cell death. Thus, SMS rather than SMases may be more important for sphingolipid homeostasis in oligodendrocytes, whereas the reverse may be true for neurons.     

Ethical,legal and social aspects of the approach in Sudan

The global malaria situation, especially in Africa, and the problems frequently encountered in chemical control of vectors such as insecticide resistance, emphasize the urgency of research, development and implementation of new vector control technologies that are applicable at regional and local levels. The successful application of the sterile insect technique (SIT) for the control of the New World screwworm Cochliomyia hominivorax and several species of fruit flies has given impetus to the use of this method for suppression or elimination of malaria vectors in some areas of Africa including Northern State of Sudan. The research and development phase of the Northern State feasibility study has been started. Sudanese stakeholders are working side-by-side with the International Atomic Energy Agency in the activities of this important phase. Several ethical, legal and social issues associated with this approach arose during this phase of the project. They need to be seriously considered and handled with care. In this paper, these issues are described, and the current and proposed activities to overcome potential hurdles to ensure success of the project are listed.     

The glucose transport system of the hyperthermophilic anaerobic bacterium Thermotoga neapolitana

The glucose transport system of the extremely thermophilic anaerobic bacterium Thermotoga neapolitana was studied with the nonmetabolizable glucose analog 2-deoxy-D-glucose (2-DOG). T. neapolitana accumulated 2-DOG against a concentration gradient in an intracellular free sugar pool that was exchangeable with external source of energy, such as pyruvate, and was inhibited by arsenate and gramicidin D. There was no phosphoenolpyruvate-dependent phosphorylation of glucose, 2-DOG, or fructose by cell extracts or toluene-treated cells, indicating the absence of a phosphoenolpyruvate:sugar phosphotransferase system. These data indicate that D-glucose is taken up by T. neapolitana via an active transport system that is energized by an ion gradient generated by ATP, derived from substrate-level phosphorylation.     

Fucosylated protein of retinal cone photoreceptor outer segments: morphological and biochemical analyses

Cone outer segments (OS) of the goldfish retina are diffusely labeled after intravitreal injection of [(3)H]fucose while rod OS remain unlabeled. By electron microscopic radioautography, the OS of red- and blue-sensitive cones are heavily labeled while green- sensitive cone OS are lightly labeled. The time-course and pattern of OS labeling in all cone types from 30 min to 24 h resemble that of incorporation of other sugars into rhodopsin in rod OS. The nature of the cone OS-specific fucosylated component(s) was examined using biochemical techniques. Cone OS were prelabeled by intravitreal injection of [(3)H]fucose 24 h before sacrifice. Photoreceptor OS were isolated using a discontinuous sucrose density gradient and it was verified by electron microscopic radioautography that the only source of radioactivity in the preparations was cone OS. The different cone types could be recognized by the heaviness of labeling, characteristic membrane spacing, and 'staining' of green cone OS in vitro with horseradish peroxidase. After acid hydrolysis of prelabeled photoreceptor membranes, 90 percent of the counts were in the neutral sugar fraction which was analyzed by thin-layer chromatography. Approximately 70 percent of the radioactivity co-chromatographed with authentic fucose. SDS-PAGE/fluorography of prelabeled photoreceptor membranes revealed a single radioactive component that was lightly stained with coomassie blue and showed an apparent molecular weight of 33,000. This cone-derived band was separated from unlabeled rod opsin which was well stained and showed an apparent mol wt of 38,000. Isoelectric focusing under denaturing conditions produced two major and one minor band of radioactivity with isoelectric points of 8.2, 8.6, and 8.8 respectively. No radioactivity was found in association with a stained band corresponding in isoelectric point to that of bovine opsin (pl, 6.2). The fucosylated component was readily digested by pronase, indicating its protein nature. Washing of the isolated OS with isotonic and hypotonic buffers failed to extract major amounts of the radioactivity, suggesting that the fucosylated component is an integral membrane protein. The presence of a fucosylated protein thus represents a major difference between cone and rod OS in the goldfish and has enabled us to identify cone OS in preparations of isolated photoreceptor membranes and to demonstrate the separation of a cone-derived glycoprotein from rod opsin.     

Spatial organization of the (H3-H4-H2A-H2B)2 histone octamer

Structure of the (H2A-H2B-H3-H4)2 histone octamer isolated from calf thymus chromatin at ionic strength 0.1 to 4.0 M NaCl, pH 7.6, was studied spectrofluorometrically. Sensitivity of lambda max tyrosine fluorescence position to structural changes of histone oligomers and to the processes of their association was shown. It were detect two ranges of cooperative changes in histone optical parameters at 0.6-1.4 M NaCl (transition I) and at 2.4-3.4 M NaCl (transition II): Transition I corresponds to the formation of equilibrium system (hexamer) + (dimer) in equilibrium octamer. Transition II corresponds to the structural changes of the histone octamer. Thus, fluorescence anisotropy increases, lambda max for fluorescence spectrum is shifted to the longer wavelengths, contributions of two components to fluorescence decay change, a fraction of fluorescence accessible to the quenching by I- decreases. Histone octamer formation is characterized by making specific contacts between the (H2A-H2B) dimer and (H3-H4)2 tetramer. These contacts are realized at gradual changing of ionic strengths (by dialysis). In the case of abrupt local changes of the environment the process is irreversibly shifted to formation of unspecific high molecular aggregates. The important function role for energetically degenerated states of histone oligomers, energy barriers between which can be overcome by changing total conditions of histone microenvironment in chromatin is discussed.     

Two structural forms of histone octamer

It has been found that histone octamer of calf thymus (H2A--H2B--H3--H4)2 can exist in two structural states--"loose" (2M NaCl) and "compact" one (4M NaCl). The compact state of the octamer is characterized by screening of part of tyrosyls for quenching effect of ions I-, longer relaxation time of tyrosyls, greater stability of histone H3 towards trypsinolysis, complete absence of interactions between histone H3 SH-groups and parachlormercuribenzoate.