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1.
Diana Oliveri Simona Candiani Manuela Parodi Eva Bertini Mario Pestarino 《Polar Biology》2005,28(5):366-371
The immunohistochemical distribution of serotonin-containing nerve fibres and cells has been described in the brain of the Antarctic fish, Trematomus bernacchii. The largest serotonergic system was associated with the diencephalic and rhombencephalic ventricles. In particular, serotonin-positive cells have been found in the lateral recess and neuropile zone of the diencephalic ventricle, where we have identified the serotonergic portion of the paraventricular organ. Numerous serotonin cells were localized in the dorsal nucleus of the raphe, the dorsal tegmental nucleus and the central gray. Two large cell groups, arranged in a pair of well-defined columns and connecting the central gray with the dorsal reticular formation, were immunostained in the region of the trigeminal nuclei. In addition, few positive cells have been found in the preoptic area and the cerebellar valvula, and few serotonergic nerve fibres, probably belonging to the lateral lemniscus, have been identified. The distribution of serotonin elements in the brain of T. bernacchii has been compared with that described in other fish, where it showed some modifications in the immunoreactive pattern. Finally, the lack of a serotonergic system at the level of the reticular superior formation has been reported; however, it was not possible to rule out a phylogenetic or environmental explanation. 相似文献
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Filippo Genovese Stefania Ferrari Giambattista Guaitoli Monica Caselli M. Paola Costi Glauco Ponterini 《Protein science : a publication of the Protein Society》2010,19(5):1023-1030
An ad hoc bioconjugation/fluorescence resonance energy transfer (FRET) assay has been designed to spectroscopically monitor the quaternary state of human thymidylate synthase dimeric protein. The approach enables the chemoselective engineering of allosteric residues while preserving the native protein functions through reversible masking of residues within the catalytic site, and is therefore suitable for activity/oligomerization dual assay screenings. It is applied to tag the two subunits of human thymidylate synthase at cysteines 43 and 43′ with an excitation energy donor/acceptor pair. The dimer–monomer equilibrium of the enzyme is then characterized through steady‐state fluorescence determination of the intersubunit resonance energy transfer efficiency. 相似文献
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5.
C-terminal peptide identification by fast atom bombardment mass spectrometry. 总被引:1,自引:0,他引:1
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A previously described technique [Rose, Simona, Offord, Prior, Otto & Thatcher (1983) Biochem. J. 215, 273-277] permits the identification of the C-terminal peptide of a protein as the only peptide that does not incorporate any 18O upon partial enzymic hydrolysis in 18O-labelled water. Formation of chemical derivatives followed by combined g.l.c.-m.s. was used in this earlier work. We now describe the isolation from protein digests, by reversed-phase h.p.l.c., of labelled and unlabelled polypeptides and their direct analysis by fast atom bombardment mass spectrometry. Under the conditions used, the 18O label is retained throughout the separation and analysis, thus permitting assignments of C-terminal peptides to be made. Enzyme-catalysed exchange of label into the terminal carboxy group was found to occur in some cases without hydrolysis of a peptide bond. This effect, which may be exploited to prepare labelled peptides, does not prevent application of the method (two separate digests must then be used). We have applied our method to the analysis of enzymic partial hydrolysates of glucagon, insulin and of several proteins produced by expression of recombinant DNA. 相似文献
6.
Summary We tested whether larval black flies actively control the positioning of their feeding appendages (labral fans), and if so, whether their posture represents a balance between the conflicting demands of drag and feeding. We compared the postures of live larvae with the postures of larvae killed by heat-shock in three different flow regimes in a laboratory experiment; we assumed that the postures of heat-killed larvae approximated a passive response to drag. The average height of the labral fans above the bed declined significantly in faster flows, and was significantly greater in live than dead larvae. There was also a significant interaction effect, since the difference between the fan heights of live and dead larvae was greater in slower flows. Two mechanisms may contribute to this result. Larvae in slower flows have to increase their fan heights more than larvae living in faster flows to achieve comparable increases in velocity and thus particle flux. In addition, muscular strength may limit the feeding postures larvae can assume. The fan heights of live larvae also varied depending on the concentration of food particles: larvae exposed to low food concentrations held their fans higher above the bed than did larvae exposed to high food concentrations in the same flow regime. This change in posture is due neither to an uneven particle concentration in the boundary layer nor to added drag from particles trapped in the labral fans. Collectively, our results indicate that these suspension feeders actively control their feeding posture, and suggest that these varying postures represent a dynamic balance between the conflicting needs of minimizing drag and maximizing feeding. 相似文献
7.
A Genovese A Accinni G Spadaro S Quattrin M Condorelli 《Archives internationales de physiologie et de biochimie》1985,93(4):331-338
Myocardial hypertrophy in Sprague-Dawley adult rats exposed to hypobaric hypoxia (0.40 atmosphere of air/18 h daily for 7 days) in a hypobaric chamber was investigated. Changes in the myocardial mass were evaluated on the basis of the dry heart weight and expressed as mg/100 g of total body weight (mean +/- SEM). Data are presented indicating that: chronic hypobaric hypoxia causes a significant degree of myocardial hypertrophy in rats; hypertrophic process involves both ventricles (the right more than the left); removal of the hypoxic stimulus leads to the disappearance of hypertrophy when evaluated as an increase in dry heart weight; hypoxia affects the synthesis of a significant amount of connective tissue in the left ventricle, which is not exposed to pressure load. The r?le of neurohumoral factors (i.e., adrenergic stimulation and catecholamines) in the development of the ventricular hypertrophy is suggested. 相似文献
8.
Multiple attractors,catastrophes and chaos in seasonally perturbed predator-prey communities 总被引:2,自引:0,他引:2
A classical predator-prey model is considered in this paper with reference to the case of periodically varying parameters.
Six elementary seasonality mechanisms are identified and analysed in detail by means of a continuation technique producing
complete bifurcation diagrams. The results show that each elementary mechanism can give rise to multiple attractors and that
catastrophic transitions can occur when suitable parameters are slightly changed. Moreover, the two classical routes to chaos,
namely, torus destruction and cascade of period doublings, are numerically detected. Since in the case of constant parameters
the model cannot have multiple attractors, catastrophes and chaos, the results support the conjecture that seasons can very
easily give rise to complex populations dynamics. 相似文献
9.
Urs Thalmann Thomas Geissmann Arsène Simona Thomas Mutschler 《International journal of primatology》1993,14(3):357-381
During a short field trip to the Special Reserve of Anjanaharibe-Sud in northeastern Madagascar, data concerning pelage coloration, behavior (especially vocalization), and ecology of indris were collected. Anjanaharibe-Sud is the northernmost locality of indri distribution. In comparison to the better-known indris from the southern part of their distribution, the indris in this region show different pelage coloration. Several types of loud vocalizations are analyzed, based on a small sample of tape recordings. Their song structure is more complicated than previously reported, containing distinct sequences of duetting. Data on behavior and ecology were collected by interviewing guides and local inhabitants. Some information contrasts with reports on the more southern indri populations. The conservation status of indris in Anjanaharibe-Sud and the future of the reserve are outlined. 相似文献
10.
Othman Al Musaimi Sophie V. Morse Lucia Lombardi Simona Serban Alessandra Basso Daryl R. Williams 《Journal of peptide science》2023,29(2):e3448
Successful manual synthesis of the TD2.2 peptide acting as a blood–brain barrier shuttle was achieved. TD2.2 was successfully synthesised by sequential condensation of four protected peptide fragments on solid-phase settings, after several unsuccessful attempts using the stepwise approach. These fragments were chosen to minimise the number of demanding amino acids (in terms of coupling, Fmoc removal) in each fragment that are expected to hamper the overall synthetic process. Thus, the hydrophobic amino acids as well as Arg(Pbf) were strategically spread over multiple fragments rather than having them congested in one fragment. This study shows how a peptide that shows big challenges in the synthesis using the common stepwise elongation methodology can be synthesised with an acceptable purity. It also emphasises that choosing the right fragment with certain amino acid constituents is key for a successful synthesis. It is worth highlighting that lower amounts of reagents were required to synthesise the final peptide with an identical purity to that obtained by the automatic synthesiser. 相似文献