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1.
This paper deals squarely with the concept of instrument, specifically, a music instrument, as a unifying agent. The topic occupied writers from Plato, through Plotinus (3rd century, CE), writers within the period known as the European Latin-based Middle Ages, and, as we will see, beyond. Seen from a historical perspective as it recurs, the topic of "body as instrument" is evidence that mind-body interactive reciprocity is not by any means solely a recent multifaceted biochemical, neurological, psychological, and cognitive, subject of inquiry; but, rather, constituted a carefully-articulated topic of discussion in the past--and, that the results of this encounter of various points of view are indeed useful for us today. Further, that alternative modes of knowledge transmission exist, for example, the allegorical mode.  相似文献   

2.
Butyrylcholinesterase (BChE, EC 3.1.1.8) is important in human cocaine metabolism despite its limited ability to hydrolyze this drug. Efforts to improve the catalytic efficiency of this enzyme have led to a quadruple mutant cocaine hydrolase, “CocH”, that in animal models of addiction appears promising for treatment of overdose and relapse. We incorporated the CocH mutations into a BChE–albumin fusion protein, “Albu-CocH”, and evaluated the pharmacokinetics of the enzyme after i.v. injection in rats. As assessed from the time course of cocaine hydrolyzing activity in plasma, Albu-CocH redistributed into extracellular fluid (16% of estimated total body water) with a t1/2 of 0.66 h and it underwent elimination with a t1/2 of 8 h. These results indicate that the enzyme has ample stability for short-term applications and may be suitable for longer-term treatment as well. Present data also confirm the markedly enhanced power of Albu-CocH for cocaine hydrolysis and they support the view that Albu-CocH might prove valuable in treating phenomena associated with cocaine abuse.  相似文献   

3.
Zooarchaeological remains from San Salvador, Bahamas, reveal trends in pre-Columbian exploitation of terrestrial, intertidal, and marine resources during the period A.D. 950–1500. Significant declines in quantities and weights of Gecarcinidae (land crabs), weights of mollusks, such as Cittarium pica (West Indian top shell) and Chiton tuberculatus/Acanthopleura granulata (chitons), and body sizes of both Sparisoma viride (stoplight parrotfish) and Serranidae (sea basses and groupers) all indicate prehistoric overexploitation. Declines in total number of identified marine taxa as well as average trophic levels of exploited marine vertebrates suggest reduced species diversity and “fishing down the marine food web.” These findings indicate that a relatively minor prehistoric human population (500–1000 people) can have significant environmental impacts, especially on small, vulnerable island ecosystems.  相似文献   

4.
5.
A sporeling culture method using gametophyte clones developed in the early 1990s led to egg discharge occurring in the dark 5 min after the start of the dark period under growth under a 11:13 L-D photoperiod. The course of egg discharge could be disturbed by light, with irradiance as low as 5–6 μmol photon m−2 s−1 causing 75–80% of the discharged eggs to detach from the oogonia and consequently to die within several hours. In order to enhance outgrowth rate of young sporophytes, a study was conducted to test the effect of controlling darkness in the period 2–3 h after dusk. When the slides were transferred from the standard 11:13 L-D regime to continuous light, eggs were discharged 5 min after the end of the light phase and peaked 5–l5 min later on first day after transfer, indicating that the female gametes “remember” the light-dark regime. This suggests the existence of an endogenous circadian rhythm. During the second and third days, very few eggs were discharged throughout the 11 h of the normal light phase of the L-D regime, indicating the inhibitory effect of continuous light and that the rhtyhm is easily damped by light.  相似文献   

6.
Occasional spontaneous “action potentiais” are found in mature hyphae of the fungus Neurospora crassa. They can arise either from low-level sinusoidal oscillations of the membrane potential or from a linear slow depolarization which accelerates into a rapid upstroke at a voltage 5–20 mV depolarized from the normal resting potential (near − 180 mV). The “action potentiais” are long-lasting, 1–2 min and at the peak reach a membrane potential near −40 mV. A 2− to 8−fold increase of membrane conductance accompanies the main depolarization, but a slight decrease of membrane conductance occurs during the slow depolarization. Two plausible mechanisms for the phenomenon are (a) periodic increases of membrane permeability to inorganic ions, particularly H+ or Cl- and (b) periodic decreases in activity of the major electrogenic pump (H+) of the Neurospora membrane, coupled with a nonlinear (inverse sigmoid) current-voltage relationship.Identification of action potential-like disturbances in fungi means that such behavior has now been found in all major biologic taxa which have been probed with suitable electrodes. As yet there is no obvious function for the events in fungi.  相似文献   

7.
The methods of assay in body fluids of 1-β-alkyl, 1-β-phenyl and 1-β-acyl glucuronic acids (“glucuronide conjugates”) have been reviewed. Most of the 78 references cited (from the literature of the period 1990–1997) concern the glucuronide conjugates of drug metabolites, and these have been considered, for reasons of accessibility, within sections of individual drug classes such as analgesics, anti-cancer agents and opioids. Other glucuronide conjugates are considered under “miscellaneous compounds”. A few gas chromatography and capillary electrophoresis methods are described, but the major technique of assay (62 citations) is reversed-phase high-performance liquid chromatography.  相似文献   

8.
The outer-most layer (“exo-layer”) of the wall was isolated from cell walls of Epidermophyton floccosum. The pure cell walls, obtained by disruption in a Ribi cell fractionator, sonication and centrifugation, were digested with snail enzyme for 12 h. Thereafter, the exo-layer preparation was obtained as the fraction resistant to the snail enzyme. Electron microscopy showed that the exo-layer is a thin, stranded network structure 10–20 nm thick. Chemical analysis of the exo-layer showed that the main components are protein (63 %), mannose (10 %) and glucosamine (17 %). Sodium dodecyl sulfate polyacrylamide gel electrophoresis has revealed that the main band is a glycoprotein containing mannose.  相似文献   

9.
Flagellar filaments are highly conserved structures in terms of the underlying symmetry of the polymer, subunit domain organization of the flagellin monomer, amino acid composition and primary sequence at the N and C termini. Traditionally, filaments are classified as “plain” or “complex.” In complex filaments, the helical lattice is perturbed in a pairwise manner such that the symmetry is reduced along the 6-start helical lines. Both plain (unperturbed) and complex (helically perturbed) components are helically symmetric and share a common lattice. The perturbation inRhizobium lupiniH13–3 results in a subunit composed of a dimer of flagellin. We have generated a ≈13 Å resolution three-dimensional density map of the complex filament ofR. lupiniH13–3 from low-dose images of negatively stained filaments. Compared to a previous map, which extended to only ≈25 Å resolution and which was generated from only five filaments containing six layer-lines each, the current map is a product of merging 139 data sets containing 66 layer-lines each. The higher resolution and improved signal-to-noise yield a detailed and interpretable density map. The density map is divided into four concentric rings. These amount to two dense cylinders interconnected by low density radial spokes and wrapped by a three-start external winding. The unperturbed component of the map is strikingly similar to the known plain filament maps and, in particular, to that ofCaulobacter crescentus. The helically perturbed component contributes mainly to the filaments's exterior (domain D3) where it comprises the tips of the outer domains interconnecting, pairwise, along the 11-start protofilaments and, again, laterally along the 6-start lines forming vertical and horizontal loops. Strong intersubunit connectivity occurs in the D2 shell and in the inner shell which is dominated by 3-start densities. The contribution of the complex component to the radial spokes seems negligible.  相似文献   

10.
The overall efficiency of the coupling between transport of α-aminoisobutyrate and the entry of Na+ in Ehrlich cells has previously been determined to be 8–10%. It was concluded that the efficiency is grossly inadequate to account for the energization of amino acid transport by the electrochemical potential gradient of Na+, as postulated by the “gradient hypothesis”. This conclusion had, however, not taken into account that a major part of the Na+ entry is not coupled to a α-aminoisobutyrate transport. The “intrinsic efficiency”, which relates the amino acid transport to the coupled Na+ entry only, has now been evaluated from available experimental data and found to be approximately adequate to account for the highest accumulation ratios for this amino acid reported. It is concluded that the gradient hypothesis cannot be rejected on energetic grounds.  相似文献   

11.
In many systems the interleukin-1 receptor antagonist opposes the effects of interleukin-1β. We considered that it might block interleukin-1β-stimulated prostaglandin production from human decidual cells. Very high levels of interleukin-1 receptor antagonist (>1000 pg/ml) had limited inhibitory effects on IL-1β-stimulated PGE2 synthesis, and lower levels of antagonist (<1000 pg/ml) increased the effects of IL-1β. Low concentrations of the antagonist alone (1–100 pg/ml) increased basal PGE2 production, whereas higher levels (10–100 ng/ml) had less effect. It seems, therefore, that in human decidua the “antagonist” is more accurately described as a partial agonist. It has been suggested that the IL-1 receptor antagonist could be used to inhibit decidual prostaglandin synthesis and thereby prevent preterm labor, but this report shows that caution should be exercised before using the receptor antagonist.  相似文献   

12.
The COST Action 2103 “Advanced Voice Function Assessment” is a joint initiative of speech processing teams (engineers and physicists) and the European Laryngological Research Group (ELRG) (laryngologists/phoniatricians). The Action officially started in December 2006, and is running till the end of 2010. 17 European countries are involved. A main objective is a better understanding of the relationship between biomechanical changes at the level of the vocal folds – as induced by pathology and tissue reaction to strain – and alterations of the acoustical voice signal. This needs to result in developing accurate, objective and clinically useful methods of investigation of voice quality in patients, and of strategies for preventing occupational voice disorders in professional speakers. Modelling is an essential tool in this process.  相似文献   

13.
Mammalian birth is accompanied by profound changes in metabolic rate that can be described in terms of body size relationship (Kleiber's rule). Whereas the fetus, probably as an adaptation to the low intrauterine pO2, exhibits an “inappropriately” low, adult-like specific metabolic rate, the term neonate undergoes a rapid metabolic increase up to the level to be expected from body size. A similar, albeit slowed, “switching-on” of metabolic size allometry is found in human preterm neonates whereas animals that are normally born in a very immature state are able to retard or even suppress the postnatal metabolic increase in favor of weight gain and O2 supply. Moreover, small immature mammalian neonates exhibit a temporary oxyconforming behavior which enhances their hypoxia tolerance, yet is lost to the extent by which the size-adjusted metabolic rate is “locked” by increasing mitochondrial density. Beyond the perinatal period, there are no other deviations from metabolic size allometry among mammals except in hibernation where the temporary “switching-off” of Kleiber's rule is accompanied by a deep reduction in tissue pO2. This gives support to the hypothesis that the postnatal metabolic increase represents an “escape from oxygen” similar to the evolutionary roots of mitochondrial respiration, and that the overall increase in specific metabolic rate with decreasing size might contribute to prevent tissues from O2 toxicity.  相似文献   

14.
Watermass stratification has been considered the essential physical condition that dinoflagellates require to bloom because of their relative inability, unlike diatoms, to tolerate the elevated shear-stress associated with water-column mixing, turbulence and high velocity, coastal currents. The swimming speeds of 71 flagellate taxa, with a focus on dinoflagellates, are compared to the turbulence fields and vertical velocities that develop during representative wind conditions, upwelling and at frontal zones. The results suggest that the classical stratification–dinoflagellate bloom paradigm needs revision. Tolerance of turbulence, growth within well-mixed watermasses and survival and dispersal while entrained within current systems are well developed capacities among dinoflagellates. Their secretion of mucous, often copious during blooms, is suggested to be an environmental engineering strategy to dampen turbulence. Biophysical tolerance of turbulence by dinoflagellates is often accompanied by high swimming speeds. Motility speeds of many species exceed in situ vertical current velocities; this also allows diel migrational patterns and other motility-based behavior to persist. Species belonging to “mixing-drift” life-form assemblages can increase their swimming speeds through chain formation, which helps to compensate for the increased turbulence and vertical water-column velocities of their habitats. The ability of dinoflagellate species to tolerate the vertical velocities of offshore, frontal zones, where abundant populations often develop, suggests that fronts may serve as “pelagic seed banks”, occurring as pelagic analogues of nearshore seed beds, from which seed stock is dispersed. The different ecologies associated with the hypothesized, “pelagic seed banks” of vegetative cells and the “seed beds” of resting stage cells deposited onto sediments are discussed. There is a contradiction in the stratification–HAB paradigm: the quiescent conditions of a stratified watermass, with its characteristic nutrient-poor conditions are expected to promote stasis of the population, rather than growth and blooms. The analyses suggest that dinoflagellate blooms do not preponderate in stratified watermasses because the bloom species are biophysically intolerant of the higher velocities and turbulence of more mixed watermasses. The watermass stratification that often accompanies flagellate blooms is probably a secondary, parallel event and less essential than some other factor(s) in triggering the observed bloom.  相似文献   

15.
Rainer Greissl   《Flora》2006,201(7):570-587
Polyads, called also massulae, are common in the Mimosaceae. Within this family, only in Calliandra (s. l.) polyads show a remarkable morphological variation: 16-grained lens-shaped massulae in the neotropical Zapoteca (syn. Calliandra p.p.), and highly asymmetric eight-grained massulae in Calliandra (s. str.). As a further specialisation the massulae in Calliandra (s. str.) possess a sticky appendage called a viscin body. The form and ontogeny of this unique two-dimensional construction of the massula is of particular interest. In Calliandra (s. str.) the octad is normally the developmental product of the initiation stage, beginning with one pollen mother cell (PMC). In total, Calliandra (s. str.) possesses eight PMCs in each anther.The dicotyledons are characterised by the simultaneous type of cytokinesis, but wall formation in Calliandra (s. str.) during meiotic division is successive, as common in monocotyledons. The first wall divides the PMC diagonally, and during the tetrad period, two clear variants of tetrads are found. One shows the typical rhomboidal arrangement and the other forms two congruent symmetrical halves. The latter probably results from early fixed, quite inflexible walls. The cells of tetrad do not separate, and four successive mitotic divisions give rise to the eight-celled massula. The direction of growth of the PMC and the massula, the sequence of division, and the position of the walls all show a strict polarity. The normal number of eight cells in each massula is sometimes exceeded without loss of viability.Calliandra (s. str.) lacks a developed “Pollenkitt”, and its asymmetrical massula is combined with the viscin body, which is involved in pollination. This viscin body is located on a specialised pollen grain at the top of the massula. With the viscin body, Calliandra (s. str.) massulae have a mechanism for immediate and persistent attachment to different surfaces. SEM is used to understand the mechanisms of attachment in detail. Furthermore, the relation between pollinators and the massula shape is investigated. Massula transport and the role of the viscin body in pollen–stigma interaction are discussed as well. The stigma of Calliandra (s. str.) is papillate and in the receptive stage, it is characterised by acquisition of a copious exudate.Zapoteca (syn. Calliandra p.p.) massulae could be distinguished histochemically from those of Calliandra (s. str.) by the main components of the “Pollenkitt”. Histochemical and physical properties of the viscin body suggest a waxy nature, including lipids in combination with unsaturated fatty acids. Proteins are present in less amounts and polysaccharides and polyglucans are absent. These results are discussed in relation to analogous phenomena in other families.The term “apex cell” is introduced to indicate the specialisation of the tip-cell of the massula by ontogeny and polarity.  相似文献   

16.
Frutalin is an α-d-galactose-binding lectin expressed in breadfruit seeds. Its isolation from plant is time-consuming and results in a heterogeneous mixture of different lectin isoforms. In order to improve and facilitate the availability of the breadfruit lectin, we cloned an optimised codifying frutalin mature sequence into the pPICZαA expression vector. This expression vector, designed for protein expression in the methylotrophic yeast Pichia pastoris, contains the Saccharomyces α-factor preprosequence to direct recombinant proteins into the secretory pathway. Soluble recombinant frutalin was detected in the culture supernatants and recognised by native frutalin antibody. Approximately 18–20 mg of recombinant lectin per litre medium was obtained from a typical small scale methanol-induced culture purified by size-exclusion chromatography. SDS–PAGE and Edman degradation analysis revealed that frutalin was expressed as a single chain protein since the four amino-acid linker peptide “T-S-S-N”, which connects α and β chains, was not cleaved. In addition, incomplete processing of the signal sequence resulted in recombinant frutalin with one Glu-Ala N-terminal repeat derived from the α-factor prosequence. Endoglycosidase treatment and SDS–PAGE analysis revealed that the recombinant frutalin was partly N-glycosylated. Further characterisation of the recombinant lectin revealed that it specifically binds to the monosaccharide Me-α-galactose presenting, nevertheless, lesser affinity than the native frutalin. Recombinant frutalin eluted from a size-exclusion chromatography column with a molecular mass of about 62–64 kDa, suggesting a tetrameric structure, however it did not agglutinate rabbit erythrocytes as native frutalin does. This work shows that the galactose-binding jacalin-related lectins four amino-acid linker peptide “T-S-S-N” does not undergo any proteolytic cleavage in the yeast P. pastoris and also that linker cleavage might not be essential for lectin sugar specificity.  相似文献   

17.
In good agreement with earlier findings (1–8) legal abortion had been induced successfully with Csapo's method of “Prostaglandin Impact” (PGI) in 44 out of 50 sedated patients. They were 25±1.1 years of age, 11.3±0.2 weeks pregnant, para 1.1±0.2. Only a PGI (10 mg PG F2α) was delivered into the extraovular space. In 44 women, this single PGI provoked 40% progesterone (P)-withdrawal in 3 hours (P < 0.001) and 64% P-withdrawal (P < 0.001) in 15.3±0.9 hours, when the patients aborted. The remaining 6 women, whose P-withdrawal was only 14% at 3 hours without continuation during 24 hours, failed to abort. Thus in PG-induced abortions the regulatory significance of rapid and continued P-withdrawal (1–8) had been verified.The side effects were mild, transient and acceptable. The “Abortion Score” was 86. There were no serious complaints or complications during the study and followup. Since even in the 6 cases of failure the cervix dilated sufficiently to allow curettage (without surgical dilatation), the therapeutic benefits of the single PGI technique should be further examined in those services, where constant medical supervision (for determining the necessity and timing of repeated PGI) is not available.  相似文献   

18.
Previous studies have identified the (4–10) heptapeptide sequence as the central core of α-MSH/ACTH peptides required for mediation of important biological activities. In the present study, the structure-activity relationships of Nle4-substituted and -bridged cyclic α-MSH analogues, which were previously shown to exhibit a wide range of melanotropic potencies from weak agonism to super potency, were examined for grooming behavioral activity in the rat following intracerebroventricular injections. The results showed that stepwise C-terminal elongation of the linear Nle4-substituted Ac-α-MSH4–10-NH2 increased grooming potencies of the peptides in a manner similar to their actions on melanocytes. The most interesting finding was the observation that cyclization of the inactive linear “central (4–10) core” of α-MSH (Ac-α-MSH4–10) to form Ac-[ ]-α-MSH4–10-NH2 resulted in a super potent agonist in the grooming assay. However, while cyclization of the (4–10) heptapeptide produced potent agonists on grooming behavior, the structure-activity relationships were different than the frog skin bioassay. These findings support the hypothesis that appropriate structural and confirmational modifications of α-MSH-related peptides can produce profound effects on the bioactivities of the peptides, and suggest that different structural-conformational requirements exist for α-MSH interactions with its various receptors.  相似文献   

19.
The TI1/UPK1b gene codes for a protein of the “tetraspan” family and is expressed as a differentiation product of the mammalian urothelium. A partial genomic clone of the human homologue of the TI1/UPK1b gene was isolated and used as probe to localize the human gene to chromosome 3q13.3–q21 byin situhybridization. Using the same probe, aTaqI restriction fragment length polymorphism, with 29% heterozygosity, was identified by Southern analysis.  相似文献   

20.
Results obtained on the effect of addition of dodecyltrimethylammonium bromide (DTAB) upon the α-chymotrypsin (α-CT) catalyzed hydrolysis of 2-naphthyl acetate (2-NA) under steady state conditions for the acyl–enzyme intermediate are compared with those previously obtained in the transient (pre-steady state or “burst”) phase. It is found that, while in the transient phase there is no effect of DTAB addition on the kinetic parameters at concentrations below the critical micelle concentration (CMC) of the surfactant, super-activity is observed when the acyl–enzyme intermediate reaches the steady state condition. This difference implies that the surfactant does not modify either the formation or the decomposition of the enzyme–substrate complex (transient phase) but notably increases the rate of disruption of the acyl–enzyme intermediate.  相似文献   

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