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1.
Although reserpine and chlorpromazine had tranquilizing effect on a number of geriatric and alcoholic patients in a state hospital, several complicating results were noted, some with a bearing on the patients' health and others that might affect the assignment of personnel. Lipoprotein studies carried out on patients receiving reserpine seemed to indicate that a reduction in the blood levels of the denser lipoprotein molecules took place during therapy. Several elderly patients receiving chlorpromazine died of diseases that were not as sharply manifest by symptoms as they might be expected to be. Hence the need for closer observation than a limited staff could afford seemed a matter for consideration. Another consideration of the same order was the possible need for increased personnel for psychotherapy in light of the more receptive condition of the patients.  相似文献   

2.
Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii.  相似文献   

3.
好氧堆肥是有机固体废弃物处理处置的有效手段之一,堆肥还田也是贫瘠土壤改良的常用措施。但好氧堆肥是一个典型的CO_2等温室气体的释放过程。如何减少堆肥过程中的CO_2释放,强化堆肥的腐殖化过程对于实现有机固体废弃物的低碳化堆肥、提高作为优良土壤改良剂的腐殖质产量具有重要意义。本文选取农林秸秆和餐厨垃圾作为堆肥原料,研究不同翻堆频率对堆肥过程中的物料减量化、腐殖化和稳定化的影响,以期发现一个较低碳的堆肥工艺,并从微生物角度初步探索了其影响机制。研究结果显示,不同的翻堆频率(分别为每2 d、4 d和6 d翻堆一次),堆料的减量化和腐殖化程度有一定差异,翻堆频率为4 d的堆肥工艺物料减量率最高为50.5%,但碳减量率最低为77.4%;而翻堆频率为2 d的堆肥工艺腐殖质产量最高;3种堆肥工艺经62 d堆肥都达到了腐熟程度,翻堆频率为4 d的堆肥工艺腐熟化程度最高。不同的翻堆频率可能通过影响堆肥过程中堆料的温度、含氧量等因素从而改变堆料中活性微生物量、种类和生物酶活性,进而影响堆料的矿化和腐殖化进程。  相似文献   

4.
New treatment approaches are needed for patients with asthma. Apolipoprotein A-I (apoA-I), the major structural protein of high-density lipoproteins, mediates reverse cholesterol transport and has atheroprotective and anti-inflammatory effects. In this study, we hypothesized that an apoA-I mimetic peptide might be effective at inhibiting asthmatic airway inflammation. A 5A peptide, which is a synthetic, bihelical apoA-I mimetic, was administered to wild-type A/J mice via osmotic mini-pump prior to the induction of house dust mite (HDM)-induced asthma. HDM-challenged mice that received the 5A apoA-I mimetic peptide had significant reductions in the number of bronchoalveolar lavage fluid eosinophils, lymphocytes, and neutrophils, as well as in histopathological evidence of airway inflammation. The reduction in airway inflammation was mediated by a reduction in the expression of Th2- and Th17-type cytokines, as well as in chemokines that promote T cell and eosinophil chemotaxis, including CCL7, CCL17, CCL11, and CCL24. Furthermore, the 5A apoA-I mimetic peptide inhibited the alternative activation of pulmonary macrophages in the lungs of HDM-challenged mice. It also abrogated the development of airway hyperresponsiveness and reduced several key features of airway remodeling, including goblet cell hyperplasia and the expression of collagen genes (Col1a1 and Col3a1). Our results demonstrate that the 5A apoA-I mimetic peptide attenuates the development of airway inflammation and airway hyperresponsiveness in an experimental murine model of HDM-induced asthma. These data support the conclusion that strategies using apoA-I mimetic peptides, such as 5A, might be developed further as a possible new treatment approach for asthma.  相似文献   

5.
Sequence variation at a major histocompatibility complex (MHC) class II gene was examined in Hypogeomys antimena, a monogamous endemic rodent of Madagascar. The study was conducted throughout its remaining geographical range (20 x 40 km) by direct sequencing and single-strand conformation polymorphism (SSCP). The objectives of the study were: (i) to investigate levels of polymorphism in the MHC complex of a highly endangered species that experienced a severe reduction in population size; and (ii) to investigate the genetic mating system by assessing the frequency of extra-pair paternity (EPP) as EPP might have important consequences to increase gene flow and, therefore, genetic variability within a population. The amplified gene segment had a very low variability (only two alleles) in H. antimena compared with other mammalian species. The alleles segregated consistently with Mendelian expectations in families. No case of EPP was found. The present data suggest no difference between the social and the genetic mating system.  相似文献   

6.
Lymphocyte cultures from 4 individuals with persistently significantly elevated frequencies of sister-chromatid exchange (SCE) were examined with no treatment, and with 2 concentrations of mitomycin C. In each of the 4 cases, the mean level of SCEs in the untreated lymphocytes exhibited a paradoxical reduction in SCE frequency when exposed to the lower (0.005 microgram/ml) of the two doses of mitomycin C. At the second higher dose of mitomycin C (0.025 microgram/ml) the mean level of SCE/cell exceeded the untreated mean. When the distributions of SCE/cell were examined it appeared that the untreated cultures had two or more populations of cells; one was in the normal SCE frequency range, while the second population was in an elevated SCE frequency range. The paradoxical reduction in SCE frequency was apparently due to elimination of, or mitotic inhibition of cells in the highest range of SCE frequency, while a small elevation in SCEs was initiated in the cells with a normal SCE frequency. Thus, mean levels of SCE/cell can be misleading. This data suggests that new exposure to the same or a different genotoxic agent might possibly result in a misleading lowering of the mean SCE frequency.  相似文献   

7.
Phylogeny of Symphytognathidae s.l. (Araneae, Araneoidea)   总被引:1,自引:0,他引:1  
The paper presents a phylogenetic analysis of Symphytognathidae sensu lato (= sensu Forster 1959): Anapidae, Micropholcommatidae, Mysmenidae and Symphytognathidae sensu stricto. These taxa include the smallest known spiders. Several authors have suggested that their similarities are merely the convergent result of reduction and loss (simplifications, minimization of organs). The data matrix comprises 80 characters scored for 12 ingroup and two outgroup taxa. The value of reduction characters is discussed in general, and the evidence regarding symphytognathids in particular is reviewed. In this case, homology explains the data better than convergence. Although Symphytognathidae s.l . is, in fact, based mainly on characters that might have accompanied miniaturization, the taxon is most probably monophyletic. Anapidae as currently defined is paraphyletic. As it constitutes, together with Micropholcommatidae, a well supported monophyletic group, the latter is herewith synonymised with the former. Mysmenidae should be relimited by transferring four Old World genera to a new family, Synaphridae. Sympyhtognathidae s.s. is also monophyletic, even though the main synapomorphy, fused chelicerae, also occurs in Mysmenidae.  相似文献   

8.
R B Raffa 《Peptides》1989,10(2):403-406
Morphine and the molluscan neuropeptide Phe-Met-Arg-Phe-NH2 (FMRFamide) were administered to mice alone or in combination intracerebroventricularly (ICV) and the effect on locomotor activity was measured. Morphine given alone (0.5 micrograms) significantly increased horizontal locomotor activity compared to vehicle-treated controls. FMRFamide at low doses (0.01-10 micrograms) had no effect of its own, but blocked the morphine-induced increase in horizontal locomotor activity. Unlike the opiate antagonist naloxone (1.0 micrograms), FMRFamide (up to 10 micrograms) had no effect on morphine-induced decrease in vertical activity. These data further support a role for FMRFamide as a modulator of opiate action, but comparison to naloxone suggests that FMRFamide might not act as a pure competitive antagonist of this opiate effect.  相似文献   

9.
The reduction of mutation rates on the mammalian X chromosome relative to autosomes is most often explained in the literature as evidence of male-driven evolution. This hypothesis attributes lowered mutation rates on the X chromosome to the fact that this chromosome spends less time in the germline of males than in the germline of females. In contrast to this majority view, two articles argued that the patterns of mutation rates across chromosomes are inconsistent with male-driven evolution. One article reported a 40% reduction in synonymous substitution rates (Ks) for X-linked genes relative to autosomes in the mouse-rat lineage. The authors argued that this reduction is too dramatic to be explained by male-driven evolution and concluded that selection has systematically reduced mutation rate on the X chromosome to a level optimal for this male-hemizygous chromosome. More recently, a second article found that chromosomal mutation rates in both the human-mouse and mouse-rat lineages were so heterogeneous that the X chromosome was not an outlier. Here again, the authors argued that this is at odds with male-driven evolution and suggested that selection has modulated chromosomal mutation rates to locally optimal levels, thus extending the argument of the first mentioned article to include autosomes. Here, we reexamine these conclusions using mouse-rat and human-mouse coding-region data. We find a more modest reduction of Ks on the X chromosome, but our results contradict the finding that the X chromosome is not distinct from autosomes. Multiple statistical tests show that Ks rates on the X chromosome differ systematically from the autosomes in both lineages. We conclude that the moderate reduction of mutation rate on the X chromosome of both lineages is consistent with male-driven evolution; however, the large variance in mutation rates across chromosomes suggests that mutation rates are affected by additional factors besides male-driven evolution. Investigation of mutation rates by synteny reveals that synteny blocks, rather than entire chromosomes, might represent the unit of mutation rate variation.  相似文献   

10.
11.
The mammalian retina contains both visual and circadian photoreceptors. In humans, nocturnal stimulation of the latter receptors leads to melatonin suppression, which might cause reduced nighttime sleepiness. Melatonin suppression is maximal when the nasal part of the retina is illuminated. Whether circadian phase shifting in humans is due to the same photoreceptors is not known. The authors explore whether phase shifts and melatonin suppression depend on the same retinal area. Twelve healthy subjects participated in a within-subjects design and received all of 3 light conditions--1) 10 lux of dim light on the whole retina, 2) 100 lux of ocular light on the nasal part of the retina, and 3) 100 lux of ocular light on the temporal part of the retina--on separate nights in random order. In all 3 conditions, pupils were dilated before and during light exposure. The protocol consisted of an adaptation night followed by a 23-h period of sustained wakefulness, during which a 4-h light pulse was presented at a time when maximal phase delays were expected. Nasal illumination resulted in an immediate suppression of melatonin but had no effect on subjective sleepiness or core body temperature (CBT). Nasal illumination delayed the subsequent melatonin rhythm by 78 min, which is significantly (p= 0.016) more than the delay drift in the dim-light condition (38 min), but had no detectable phase-shifting effect on the CBT rhythm. Temporal illumination suppressed melatonin less than the nasal illumination and had no effect on subjective sleepiness and CBT. Temporal illumination delayed neither the melatonin rhythm nor the CBT rhythm. The data show that the suppression of melatonin does not necessarily result in a reduction of subjective sleepiness and an elevation ofCBT. In addition, 100 lux of bright white light is strong enough to affect the photoreceptors responsible for the suppression of melatonin but not strong enough to have a significant effect on sleepiness and CBT. This may be due to the larger variability of the latter variables.  相似文献   

12.
Plants growing under elevated CO2 concentration may acclimatize to this environmental change by modification of chemical, physiological, and/or morphological traits. As a consequence, not only plant functioning but also plant–insect interactions might be altered, with important consequences particularly for agricultural systems. Whereas most studies have focused on the plant acclimation effects of elevated CO2 with regard to crop growth and productivity, acclimation effects on the behavioral response of insects associated with these plants have been largely neglected. In this study, we used a model system comprised of Brussels sprout Brassica oleraceae var. gemmifera and a specialized herbivorous insect, the cabbage aphid Brevicoryne brassicae, to test for the effects of various periods of exposure to an elevated (2× ambient) CO2 concentration on key plant functional traits and on host plant location behavior by the insect, assessed as plant colonization rates. Elevated CO2 had no measurable effect on colonization rates or total plant volatile emissions after a 2-week exposure, but it led to 15 and 26 % reductions in plant colonization rates after 6- and 10-week exposures, respectively. This reduction in plant colonization was associated with significant decreases in leaf stomatal conductance and plant volatile emission. Terpene emission, in particular, exhibited a great reduction after the 10-week exposure to elevated CO2. Our results provide empirical evidence that plants might acclimatize to a future increase in CO2, and that these acclimation responses might affect host plant choice and colonization behavior by herbivorous insects, which might be advantageous from the plant’s perspective.  相似文献   

13.
The effect of corticosterone (CC, 0.4 and 1 microgram/ml) and of hydrocortisone (HC, 20 and 40 micrograms/ml) on the spontaneous motility and on prostaglandin (PG) generation in the uterus from ovariectomized rats, was studied. Both concentrations of CC depressed significantly the frequency of contractions but the isometric developed tension was affected only by the higher dose. HC significantly inhibited the isometric developed tension at both concentrations whereas the contractile frequency was only depressed by the higher one. The CC-inhibited motility was accompanied by a reduction in the amount of PGs released from the uterus into the bath solution. In addition, the influences of arachidonic acid (AA), linoleic acid (LA) and gamma-linolenic acid (alpha-LA) - 1 or 2 micrograms/ml - on the depression evoked by CC, were also explored. The fatty acids had no effect on the spontaneous uterine motility except in the case of alpha-LA at 1 microgram/ml. alpha-LA completely blocked the CC-evoked reduction of both tension and frequency; AA (1 microgram/ml) elicited a reversion only on frequency whereas LA had no effect at all. This reversion by a fatty acid PG-precursor might indicate that CC is able to diminish substrate availability for PG synthesis in the rat uterus.  相似文献   

14.
Mitochondrial thioredoxin reductase was purified from bovine adrenal cortex. The enzyme is a first protein component in the mitochondrial thioredoxin-dependent peroxide reductase system. The purified reductase exhibited an apparent molecular mass of 56 kDa on SDS/PAGE, whereas the native protein was about 100 kDa, suggesting a homodimeric structure. It catalysed NADPH-dependent reduction of 5, 5'dithiobis(2-nitrobenzoic acid) and thioredoxins from various origins but not glutathione, oxidized dithiothreitol, DL-alpha-lipoic acid, or insulin. Amino acid and nucleotide sequence analyses revealed that it had a presequence composed of 21 amino acids which had features characteristic of a mitochondrial targeting signal. The amino acid sequence of the mature protein was similar to that of bovine cytosolic thioredoxin reductase (57%) and of human glutathione reductase (34%) and less similar to that of Escherichia coli (19%) or yeast (17%) enzymes. Human and bovine cytosolic thioredoxin reductase were recently identified to contain selenocysteine (Sec) as one of their amino acid constituents. We also identified Sec in the C-terminal region of mitochondrial (mt)-thioredoxin reductase by means of MS and amino acid sequence analyses of the C-terminal fragment. The four-amino acid motif, Gly-Cys-Sec-Gly, which is conserved among all Sec-containing thioredoxin reductases, probably functions as the third redox centre of the enzyme, as the mitochondrial reductase was inhibited by 1-chloro-2,4-dinitrobenzene, which was reported to modify Sec and Cys covalently. It is known that mammalian thioredoxin reductase is different from bacterial or yeast enzyme in, for example, their subunit molecular masses and domain structures. These two different types of enzymes with similar activity are suggested to have evolved convergently. Our data clearly show that mitochondria, which might have originated from symbiotic prokaryotes, contain thioredoxin reductase similar to the cytosolic enzyme and different from the bacterial one.  相似文献   

15.
The expression product of ct120a,a novel gene isolated from human chromosome 17p13.3in our laboratory,was predicted to have seven transmembrane domains and could cause malignanttransformation of mouse NIH3T3 cells.There existed an mRNA splicing variant of ct120a,namely ct120b,which had a 96-nucleotide deletion and produced an in-frame loss of 32 amino acids from codon 136 tocodon 167 of CT120A.The CT120B protein was predicted to have six transmembrane domains.In thisstudy,we observed that the green fluorescent protein-tagged CT120B was localized on plasma membraneand in cytoplasm in SPC-A-1 cells.The expression of CT120B/A in normal lung tissue and in lung cancercells was also examined.Results showed that the stable CT120B overexpression in SPC-A-1 cells resultedin a reduction of cell growth rate,and inhibited tumorigenecity and anchorage-independent growth in nudemice.The functions of CT120A and CT120B for cell growth appeared antagonistic.We suggested that thedelayed G_1/S phase transition might contribute to the inhibitory activities of CT120B on cell growth and thatthe deleted 32 amino acids missing in CT120B might be essential for the oncogenetic activities of CT120A.  相似文献   

16.
Potassium is one of the principle plant nutrients underpinning crop yield production and quality determination. While involved in many physiological processes, potassium's impact on water relations, photosynthesis, assimilate transport and enzyme activation can have direct consequences on crop productivity. Potassium deficiency can lead to a reduction in both the number of leaves produced and the size of individual leaves. Coupling this reduced amount of photosynthetic source material with a reduction in the photosynthetic rate per unit leaf area, and the result is an overall reduction in the amount of photosynthetic assimilates available for growth. The production of less photosynthetic assimilates and reduced assimilate transport out of the leaves to the developing fruit greatly contributes to the negative consequences that deficiencies of potassium have on yield and quality production. Goals aimed toward increasing crop productivity and improved quality dictate either increased potassium supply or more efficient use of potassium. Developing plants that more efficiently use potassium might be a worthwhile goal for geneticists.  相似文献   

17.
A strategy that uses ultrafiltration (UF) to concentrate microorganisms from water samples has been developed and tested. This strategy was tested using 100-liter water samples with volume reduction achieved through ultrafiltration and recycling the microorganisms of interest through a retentate vessel, rather than returning them to the sample container, where they might pose an incremental hazard to sample takers or the environment. Three protocols based on this strategy were tested. The first protocol entailed sample volume reduction and collection of the final reduced sample. The second and third protocols both incorporated pretreatment of the filter and fluid lines with a solution to prevent microorganisms from adhering. In the second protocol, the filter was back flushed with a surfactant solution to recover microorganisms. The third protocol used recirculation of a surfactant solution to recover microorganisms. Tests were undertaken using 100-liter water samples spiked with approximately 100 or 1000 microorganisms (1 or 10 per liter). Test microorganisms included Bacillus anthracis Sterne strain, Bacillus atrophaeus subsp. globigii, and Cryptosporidium parvum. The first protocol had significantly lower recovery than the other two. Back flushing resulted in higher recovery than forward flushing, but the difference was not statistically significant.  相似文献   

18.
Peripheral treatment with the serotonin releaser fenfluramine or the serotonin agonist quipazine abolished lordosis behavior in ovariectomized estradiol and progesterone-primed female guinea pigs. Quipazine was also effective when administered into a lateral cerebroventricle. The lowest dose of fenfluramine that induced myoclonus (10 mg/kg) was higher than the dose needed to inhibit lordosis (5 mg/kg). Therefore, it appears that myoclonus and lordosis are differentially sensitive to serotonin agonists. The effects of quipazine on lordosis were time dependent. Quipazine had no effect on lordosis when given prior to the onset of sexual receptivity. These data suggest that serotonin agonists might be effective only when progesterone has had sufficient time to induce sexual receptivity. Quipazine did not affect cytoplasmic progestin receptors in brain areas involved in steroid hormone effects on lordosis. This finding, and the finding that quipazine had no effect on lordosis when given prior to the onset of sexual receptivity, suggest increased serotonin transmission does not interfere with estrogen priming or sensitivity of hypothalamic cells to progesterone.  相似文献   

19.
Here, we test the hypothesis that virulent malaria parasites are less susceptible to drug treatment than less virulent parasites. If true, drug treatment might promote the evolution of more virulent parasites (defined here as those doing more harm to hosts). Drug-resistance mechanisms that protect parasites through interactions with drug molecules at the sub-cellular level are well known. However, parasite phenotypes associated with virulence might also help parasites survive in the presence of drugs. For example, rapidly replicating parasites might be better able to recover in the host if drug treatment fails to eliminate parasites. We quantified the effects of drug treatment on the in-host survival and between-host transmission of rodent malaria (Plasmodium chabaudi) parasites which differed in virulence and had never been previously exposed to drugs. In all our treatment regimens and in single- and mixed-genotype infections, virulent parasites were less sensitive to pyrimethamine and artemisinin, the two antimalarial drugs we tested. Virulent parasites also achieved disproportionately greater transmission when exposed to pyrimethamine. Overall, our data suggest that drug treatment can select for more virulent parasites. Drugs targeting transmission stages (such as artemisinin) may minimize the evolutionary advantage of virulence in drug-treated infections.  相似文献   

20.
The first steps in eukaryotic evolution appear difficult to retrace despite the availability of an increasing amount of data. Current molecular phylogenies suggest that the eukaryotic tree would be better represented as a bush of major lineages whose order of emerge is poorly resolved. Such lack of resolution is often explained by a radiation event that would have left very little ancient signal in eukaryotic molecular markers. We suggest a complementary genomic approach that might help tackling this major issue. It rests on a hypothesis, the genome reduction hypothesis (GRH), suggesting that the divergence of major eukaryotic lineages might have been coupled with independent genomic reduction events, starting from a large and partially redundant chimerical genome. Thus, significant and coherent patterns of shared ancestral gene losses between major eukaryotic lineages might help polarizing the most basal nodes in the eukaryotic phylogeny. We propose a test for the GRH that exploits the increasing availability of complete eukaryotic genomes in public databases.  相似文献   

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