Optimization of the chiral separation of some 2-arylpropionic acids on an avidin column by modeling a combined response

The enantiomeric separation of some nonsteroidal antiinflammatory drugs was investigated on an avidin column. An experimental design approach (central composite design) was used to evaluate the effects of three method parameters (pH, concentration of organic modifier, and buffer concentration) on the analysis time and the resolution, as well as to model these responses. This revealed that the organic modifier concentration and sometimes the pH are significant parameters to control because of their influence on both analysis time and resolution. Furthermore, the central composite design results were combined in a multicriteria decision-making approach in order to obtain a set of optimal experimental conditions leading to the most desirable compromise between resolution and analysis time.     

The Alzheimer-related gene presenilin-1 facilitates sonic hedgehog expression in Xenopus primary neurogenesis

We analyzed the influence of presenilins on the genetic cascades that control neuronal differentiation in Xenopus embryos. Resembling sonic hedgehog (shh) overexpression, presenilin mRNA injection reduced the number of N-tubulin+ primary neurons and modulated Gli3 and Zic2 according to their roles in activating and repressing primary neurogenesis, respectively. Presenilin increased shh expression within its normal domain, mainly in the floor plate, whereas an antisense X-presenilin-alpha morpholino oligonucleotide reduced shh expression. Both shh and presenilin promoted cell proliferation and apoptosis, but the effects of shh were widely distributed, while those resulting from presenilin injection coincided with the range of shh signaling. We suggest that presenilin may modulate primary neurogenesis, proliferation, and apoptosis in the neural plate, through the enhancement of shh signaling.     

Propolis from Chilean matorral hives

Viscidone (0.5%), vanillin, 3',4'-(methylendioxy)acetophenone, 3-ethoxy-4-methoxybenzaldehyde, cinnamic acid, 3-methoxy-4-hydroxymethyl ester were isolated from propolis of hives from Cuncumen. This is the first report on propolis composition of an arid and a Mediterranean type climate area.     

The effect of melatonin implants on the response to the male effect and on the subsequent cyclicity of Rasa Aragonesa ewes implanted in April

Rasa Aragonesa ewes were used to evalutate whether treatment with melatonin implants in spring could modify: (i) the response to the male effect in terms of oestrous behaviour and ovulation rate; and (ii) the maintenance of sexual activity and ovulation rate at medium term, i.e. over the next 306 days. On 12 April, 42 ewes were divided into two groups, with (M; n = 21) or without (C; n = 21) a subcutaneous implant containing 18 mg melatonin. On 17 May (day 0), three aproned rams were introduced to each group to induce a ram effect. Ewes were observed for oestrus daily. The rams were removed 40 days later after which one aproned ram was introduced daily. Oestrous detection continued until 28 February, 306 days after the first male-female contact. The ovulation rate was determined by endoscopy in the first three cycles after ram introduction and in September-October and January. Progesterone was assayed from blood samples taken on 6 May, 10 and from day 0 to day 22 after ram introduction. Luteal activity before ram introduction was seen in 33% (M) and 29 (C)% of the ewes, respectively. Significantly more M ewes showed oestrous behaviour during the first 40 days after ram introduction (M: 100%; C: 62%; P < 0.01). Similar differences were observed for ewes anovulatory at ram introduction (M: 100%, C: 47%; P < 0.01). These differences were maintained over the three oestrous cycles in both groups. Treatment with melatonin implants was without detrimental effect on cyclic functions in the following breeding season, after seasonal anoestrus. Melatonin treatment significantly increased (P < 0.05) the mean ovulation rate of the first (1.62 +/- 0.11 versus 1.31 +/- 0.13), second (1.78 +/- 0.15 versus 1.36 +/- 0.15) and third cycles (M: 1.73 +/- 0.12 versus C: 1.27 +/- 0.14). There was a significant interaction between the effects of cyclicity at day 0 and melatonin treatment on the ovulation rate in the first cycle (P < 0.05). The mean ovulation rates of both groups were similar at the beginning (September) and middle (January) of the subsequent breeding season. Overall, the results confirmed that melatonin implants, combined with the ram effect, improved the reproductive parameters of reduced-seasonality ewes during spring mating, without impairing sexual activity or ovulation rate during the subsequent breeding season.     

Effects of betamethasone,sulindac and quinacrine drugs on the inflammatory neoangiogenesis response induced by polyurethane sponge implanted in mouse

In this study, we showed the effect of the betamethasone, sulindac and quinacrine alone or combined, on the inflammatory angiogenesis promoted by polyurethane sponge on mice. The main finding reported here is that the formation of new blood vessels was strongly inhibited by low concentration of betamethasone, sulindac or quinacrine, whether alone or in combination. It is known that steroidal anti-inflammatory drugs inhibit the enzymes required for the production of prostaglandins through a nuclear glucocorticoid receptor (GR) mediated mechanism. This mechanism may occur in endothelial cells as well. Considering that activity of cyclo-oxigenases 1 and 2 is inhibited by sulindac, and that these enzymes are located in the stromal tissue, we propose that the anti-angiogenic effect of these agents may occur via inhibition of both COX isoforms. On the other hand, quinacrine inhibited PLA2 activity, and we propose here that the anti-angiogenic effect occurs via inhibition of the enzyme PLA2. The potentiated effect of the association of betamethasone, sulindac and quinacrine may have some therapeutic benefit in the control of pathological angiogenesis. Further studies are required to validate these propositions.     

Study of the first hours of microvinification by the use of osmotic stress-response genes as probes

When yeast cells are inoculated into grape must for vinification they find stress conditions because of osmolarity, which is due to very high sugar concentration, and pH lower than 4. In this work an analysis of the expression of three osmotic stress induced genes (GPD1, HSP12 and HSP104) under microvinification conditions is shown as a way to probe those stress situations and the regulatory mechanisms that control them. The results indicate that during the first hours of microvinification there is an increase in the GPDI mRNA levels with a maximum about one hour after inoculation, and a decrease in the amount of HSP12 and HSP104 mRNAs, although with differences between them. The RNA steady-state levels of all the genes considered, and in some cases the microvinification progress are significantly affected by the composition of the must (pH, nature of the osmotic agent and carbon source). These results point out the importance of the control of these parameters and the yeast molecular response during the first hours of vinification for an accurate winemaking process.     

Confirmation of the D configuration of the 2-substituted arabinitol 1-phosphate residue in the capsular polysaccharide from Streptococcus pneumoniae Type 17F

The absolute configuration of the 2-substituted arabinitol 1-phosphate residue present in the repeating unit of the capsular polysaccharide (CPS) from Streptococcus pneumoniae Type 17F is confirmed as D, based on a comparison of proton and carbon chemical shifts in a synthetic oligosaccharide and in an oligosaccharide derived from the CPS by degradation.     

Sphingomyelinase cleavage of sphingomyelin in pure and mixed lipid membranes. Influence of the physical state of the sphingolipid

Sphingomyelin hydrolysis by sphingomyelinase is essential in regulating membrane levels of ceramide, a well-known metabolic signal. Since natural sphingomyelins have a gel-to-fluid transition temperature in the range of the physiological temperatures of mammals and birds, it is important to understand the influence of the physical state of the lipid on the enzyme activity. With that aim, large unilamellar vesicles consisting of pure egg sphingomyelin (gel-to-fluid crystalline transition temperature ca. 39 degrees C) were treated with sphingomyelinase in the temperature range 10-70 degrees C. The vesicles were also examined by differential scanning calorimetry (DSC). Shingomyelinase was active on pure sphingomyelin bilayers, leading to concomitant lipid hydrolysis, vesicle aggregation, and leakage of aqueous liposomal contents. Enzyme activity was found to be much higher when the substrate was in the fluid than when it was in the gel state. Sphingomyelinase activity was found to exhibit lag times, followed by bursts of activity. Lag times decreased markedly when the substrate went from the gel to the fluid state. When egg phosphatidylcholine, or egg phosphatidylethanolamine were included in the bilayer composition together with sphingomyelin, sphingomyelinase activity at 37 degrees C, that was negligible for the pure sphingolipid bilayers, was seen to increase with the proportion of glycerophospholipid, while the latency times became progressively shorter. A DSC study of the mixed-lipid vesicles revealed that both phosphatidylcholine and phosphatidyletanolamine decreased in a dose-dependent way the transition temperature of sphingomyelin. Thus, as those glycerophospholipids were added to the membrane composition, the proportion of sphingomyelin in the fluid state at 37 degrees C increased accordingly, in this way becoming amenable to rapid hydrolysis by the enzyme. Thus sphingomyelinase requires the substrate in bilayer form to be in the fluid state, irrespective of whether this is achieved through a thermotropic transition or by modulating bilayer composition.     

Extracellular matrix remodeling and metalloproteinase involvement during intestine regeneration in the sea cucumber Holothuria glaberrima

The sea cucumber, Holothuria glaberrima, has the capacity to regenerate its internal organs. Intestinal regeneration is accomplished by the thickening of the mesenteric border and the invasion of this thickening by mucosal epithelium from the esophagus and the cloaca. Extracellular matrix (ECM) remodeling has been associated with morphogenetic events during embryonic development and regeneration. We have used immunohistochemical techniques against ECM components to show that differential changes occur in the ECM during early regeneration. Labeling of fibrous collagenous components and muscle-related laminin disappear from the regenerating intestine and mesentery, while fibronectin labeling and 4G7 (an echinoderm ECM component) are continuously present. Western blots confirm a decrease in fibrous collagen content during the first 2 weeks of regeneration. We have also identified five 1,10-phenanthroline-sensitive bands in collagen gelatin zymographs. The gelatinolytic activities of these bands are enhanced during early stages of regeneration, suggesting that the metalloprotease activity is associated with ECM remodeling. Inhibition of MMPs in vivo with 1,10-phenanthroline, p-aminobenzoyl-Gly-Pro-D-Leu-D-Ala hydroxamate or N-CBZ-Pro-Leu-Gly hydroxamate produces a reversible inhibition of intestinal regeneration and ECM remodeling. Our results show that significant changes in ECM content occur during intestine regeneration in the sea cucumber and that the onset of these changes is correlated to the proteolytic activities of MMPs.