Search results for "CLASSIFICATION"
showing 10 items of 29475 documents
Studies on zymogenicity and solubilization of chitin synthase from Candida albicans
1985
The zymogenic form of the chitin synthase present in mixed membrane preparations was extracted by digitonin treatment. The residual extracted membranes exclusively retained the basal activity. Trypsin activation of the zymogenic form of the enzyme did not modify the digitonin solubilization characteristics of the original zymogenic form, suggesting significant differences between ‘in vivo’ activation of chitin synthase and that carried out by trypsin ‘in vitro’.
Daidzein has neuroprotective effects through ligand-binding-independent PPARγ activation.
2011
Phytoestrogens are a group of plant-derived compounds that include mainly isoflavones like daidzein. Phytoestrogens prevent neuronal damage and improve outcome in experimental stroke; however, the mechanisms of this neuroprotective action have not been fully elucidated. In this context, it has been postulated that phytoestrogens might activate the peroxisome proliferator-activated receptor-γ (PPARγ), which exerts neuroprotective effects in several settings. The aim of this study was to determine whether the phytoestrogen daidzein elicits beneficial actions in neuronal cells by mechanisms involving activation of PPARγ. Our results show that daidzein (0.05-5 μM) decreases cell death induced b…
Locust neuropeptides stimulating sex pheromone production in female European corn borer moth, Ostrinia nubilalis
1990
Abstract The presence of a pheromonotropically active hormone (PBAN-like substance) from locust organs, ( Locusta migratoria ) has been demonstrated. Extracts of brain, corpora cardiaca, corpora allata, suboesophageal ganglia and thoracic ganglia of L. migratoria caused highly pheromonotropic responses in decapitated females of the European corn borer moth ( Ostrinia nubilalis ). The highest activity per unit weight of tissue was found in the corpora cardiaca and corpora allata of the locust followed by the brain plus suboesophageal ganglion of O. nubilalis . Following 8 days of disconnection, separating the corpora allata from the corpora cardiaca and suboesophageal ganglion, the pheromono…
Circadian rhythm and effects of light on cAMP content of the dwarf hamster suprachiasmatic nucleus
1998
The present study was conducted in the dwarf hamster (Phodopus sungorus) to investigate whether a circadian rhythm is present in the content of the second messenger cyclic adenosine 3',5'-monophosphate (cAMP) in the suprachiasmatic nucleus (SCN), the endogenous clock in mammals. In animals held under light/dark conditions (LD), we observed high levels at the end of the light phase and low levels during the night in frozen SCN punches. In animals held in continuous dark, a similar rhythm was seen although a second peak was present in the subjective day. In senile hamsters under LD, the decrease of cAMP levels at the light transition was not seen. These data, obtained for the first time from …
A new method to value efficiency of enzyme blends for pancreatic tissue digestion.
2010
Islet transplantation, since the 90’s, has been resulting to be one of the best successful example of human cell therapy. Nevertheless, islet isolation procedure is not completely standardized; in fact, more than fifty percent of islets procedures don’t arrive to their transplantation. This is due both to the variability of donor’s pancreas and to an unpredictable enzymatic blend efficiency. Enzymes used in pancreas digestion are extracted from Clostridium histolyticum bacteria and digest several substrates. In particular they have strong collagenolytic activity compared to vertebrate collagenases. However, several impediments persist in human islet isolation success probably due to the var…
Lack of "Synaptic" Ribbons in the Pineal Gland of BALB/c Mice
1988
In mammalian pinealocytes "synaptic" ribbons (SR) are regularly occurring organelles that are functionally poorly understood. Since in a number of studies on the mouse pineal gland the presence of SR has not been mentioned, it was the aim of this investigation to quantitate SR in mice. BALB/c mice were chosen, which have recently been shown to have a genetic defect for melatonin synthesis. The pineals of 15 mice killed at night, when SR numbers are normally high, were examined electron microscopically, scanning an area of greater than 20,000 micron 2 per gland. In none of these pineals were SR detected. It is concluded that the lack or extreme rarity of SR in laboratory mice may be related …
Photo-DHEA--a functional photoreactive dehydroepiandrosterone (DHEA) analog.
2011
Abstract The steroid hormone dehydroepiandrosterone (DHEA) has beneficial effects on vascular function, survival of neurons, and fatty acid metabolism. However, a specific receptor for DHEA has not been identified to date. Here, we describe the synthesis of a photoreactive DHEA derivative (Photo-DHEA). In Photo-DHEA, typical characteristics of DHEA are conserved: (i) a “planar” tetracyclic ring system with a Δ 5 double bond, (ii) a 3β-hydroxyl group, and (iii) a keto group at C17. In cell-based assays, Photo-DHEA showed the same properties as DHEA. We conclude that Photo-DHEA is suitable for radioiodination to yield a tool for the identification of the elusive DHEA receptor.
Circadian variations of ?synaptic? bodies in the pineal glands of Brattleboro rats
1990
The function of the mammalian pineal gland is regulated primarily by the sympathetic system. Arginine-vasopressin (AVP) may also be involved in the regulation of pineal melatonin synthesis under experimental conditions. The present study was conducted in the AVP-deficient rat strain, the Brattleboro rat, to investigate whether the numbers and rhythms of pineal "synaptic" bodies in this strain are different from those found in intact rats. AVP or its non-vasoconstrictive analog, deamino-D-AVP, was also injected intra-arterially in Brattleboro or Sprague-Dawley rats to test whether this procedure influences "synaptic" body numbers. Brattleboro rats were killed at different time-points through…
Distribution of corticotropin-releasing factor-immunoreactive neurons in the central nervous system of the domestic chicken and Japanese quail
2004
In birds, as in mammals, corticotropin-releasing factor (CRF) is present in a number of extrahypothalamic brain regions, indicating that CRF may play a role in physiological and behavioral responses other than the control of adrenocorticotropin hormone release by the pituitary. To provide a foundation for investigation of the roles of CRF in the control of avian behavior, the distribution of CRF immunoreactivity was determined throughout the central nervous system of the domestic chicken (Gallus domesticus) and Japanese quail (Coturnix japonica). The distribution of CRF-immunoreactive (-ir) perikarya and fibers in the chicken and quail brain was found to be more extensive than previously re…
Role of glutathione in Thiobencarb resistance in the European eel Anguilla anguilla.
2000
Glutathione-dependent defense against xenobiotic toxicity is a multifaceted phenomenon that has been well characterized in mammals. In the present study, eels of species Anguilla anguilla were exposed to 15 ppm of the herbicide thiobencarb (S-4-chlorobenzyl diethylthiocarbamate) for 96 h. Eels exposed to the pesticide were grouped in 24-h intervals according to their time of death, while surviving intoxicated eels constituted another group (live animals). Glutathione content (GSx, GSH, GSSG) was determined in liver and muscle tissues of the dead and live (intoxicated) animals and compared to control values (nonexposed eels). The fish that died before 96 h of exposure were considered suscept…