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1.
μ-Calpain is a calcium-dependent cysteine protease, which is activated by μM concentration of calcium in vitro. Disrupted intracellular calcium homeostasis leads to hyper-activation of μ-calpain. Hyper-activated μ-calpain enhances the accumulation of β-amyloid peptide by increasing the expression level of β-secretase (BACE1) and induces hyper-phosphorylation of tau along with the formation of neurofibrillary tangle by mediating p35 cleavage into p25, both of which are the major mechanisms of neurodegeneration in Alzheimer's disease (AD). Hence, inhibition of μ-calpain activity is very important in the treatment and prevention of AD. In this study, conjugated linoleic acid (CLA), an eighteen-carbon unsaturated fatty acid, was discovered as a μ-calpain-specific inhibitor. CLA showed neuroprotective effects against neurotoxins such as H2O2 and Aβ1–42 in SH-SY5Y cells, and inhibited Aβ oligomerization/fibrillation and Aβ-induced Zona Occludens-1 degradation. In addition, CLA decreased the levels of proapoptotic proteins, p35 conversion to p25 and tau phosphorylation. These findings implicate CLA as a new core structure for selective μ-calpain inhibitors with neuroprotective effects. CLA should be further evaluated for its potential use as an AD therapeutic agent.  相似文献   

2.
In Drosophila melanogaster, the chitinous microfibrils arising from the tips of the epidermal villi in adult cuticles remain irregular and loose in the mutant ebony (which fails in cuticular incorporation of -alanine) but closely knit and regular in normal flies. Addition of -alanine to cuticles from which nonchitinous materials have been removed with alkali converts the loose arrangement of the microfibrils to a compact and sharply delineated arrangement. -alanine also accelerates tyrosinase-catalyzed oxidation of N-acetyldopamine by reacting with the oxidized product of the reaction to produce an orange-red complex. Similarly, -alanine accelerates oxidation of N-acetyldopamine when these two substances are added to fluids from the hemocoel, to lead to tanning instead of normal blackening. These findings may help explain why -alanine induces tanning while inhibiting melanization in insects.This study was supported by Grant GM-18680 from the National Institutes of Health.  相似文献   

3.
The authors have succeeded in isolating an antibiotic, from the cultured filtrate of Asp. oryzae, responsible for, at least, the majority of the active substances against hiochi-bacteria, as pale yellow crystals of m.p. 152~153°C. It has been proved that this antibiotic is identical with hydroxyaspergillic acid. The minimum concentration for complete inhibition in diluted Saké-peptone medium against true hiochi-bacilli, Lactobacillus homohiochii H-42 and Lactobacillus heterohiochii H-l, was 10 γ/ml, and that against hiochi-lactobacilli H-7 and H-34 20 γ/ml.  相似文献   

4.
A rapid stepwise measurement for the activities of calpastatin and μ- and m-calpains was developed by using 2-stage elution at pH 8.5 and then 7.0. The activities of calpastatin, μ-calpain and m-calpain can be rapidly assayed following the separation on DEAE-Sephacel chromatography by a 2 stage elution with 90 mM NaCl (pH 8.5), and then by 200 and 300 mM NaCl in elution buffer (pH 7.0). No significant differences in the recovery of these proteinases and inhibitor was observed between stepwise gradient and linear gradient methods.  相似文献   

5.
Efficiency of imidacloprid and pymetrozine on population growth parameters of cabbage aphid, Brevicoryne brassicae L. (Homoptera: Aphididae) was determined using demographic toxicology by leaf dip method. At first, bioassay tests were performed. The LC50 value and confidence limit for imidacloprid and pymetrozine were 1.61 × 10^-5 mol/L (0.74 × 10^-5-2.66 × 10^-5) and 2.14 × 10^-4 mol/L (1.24 × 10^-4-3.40 × 10^-4), respectively. To evaluate the sublethal effect of two insecticides on population growth parameters of cabbage aphid, LC30 concentrations of imidacloprid and pymetrozine were used at 5 mol/L and 30 mol/L. The experiments were carried out in a incubator at 20±1℃, 60% ± 5% RH and 16:8 (L:D) photoperiod on canola seedlings, Brassica napus L. var. 'PF'. Net fecundity rate decreased in both insecticide-treated populations. Intrinsic rates of increase (rm) were lower in imidacloprid and pymetrozine treatments than in controls. Intrinsic birth rates also decreased in treated populations. There was a relative increase in intrinsic death rates of treated populations. The mean generation times and doubling time were also lower in populations treated with insecticides than in controls. There was a considerable reduction in the average numbers of nymphs reproduced per female as compared with the control. The average longevity of female adults in the control was significantly different from those treated with imidacloprid and pymetrozine. However, there was no significant differences in aphid life-table parameters between the two insecticide-treated populations (P 〉 0.01).  相似文献   

6.
7.
Dark grown Scenedesmus obliquus strain PG1 accumulated -carotene and phytoene as its major carotenoids. On illumination of dark-grown cultures in air/CO2, cyclic carotenes and xanthophylls were formed, apparently at the expense of the accumulated phytoene and -carotene. This interconversion of carotenoids was accompanied by chlorophyll synthesis. In an atmosphere of nitrogen/CO2 the light-induced changes occurred more slowly and in nitrogen alone the changes were incomplete. No massive production of cyclic carotenes from the accumulated -carotene was observed in cultures illuminated under anaerobic conditions.  相似文献   

8.
Ploetz RC 《Mycopathologia》2004,157(2):225-231
A series of glasshouse and incubator studies were conducted to investigate the role played by Pythium splendens in a decline disorder of carambola, Averrhoa carambola. Plants, 4-6 months old, were grown in native calcareous soil either infested or not infested with the pathogen. Isolates recovered from atemoya, carambola and passion fruit grew optimally at 30 degrees C, and significantly (P < 0.05) increased root necrosis and reduced root, shoot and total biomass of carambola. Temperature had a profound impact on the latter relationships. Two or more times more necrosis developed at 10 and 15 degrees C than at 25 and 30 degrees C. Total biomass accumulations were over four times greater at 30 degrees C than at 10 degrees C, and were always lower in soil infested with P. splendens. When biomass totals from infested and noninfested soil were compared, relative values were lowest at 15 and 20 degrees C and were almost two times greater at 30 degrees C than at 20 degrees C. Root infection by P. splendens was greatest at 15 and 20 degrees C, far below the species' optimum for growth, and at 30 degrees C was over nine times lower than at 15 and 20 degrees C. This is the first detailed report of P. splendens as a pathogen of carambola.  相似文献   

9.
The benefits of using white clover in pastures have been widely recognised for many years. However, clover is perceived as being unreliable because of its typically low content, which is spatially and temporally variable, in mixed pastures. One proposed solution to increase the proportion of clover in the diet of grazing animals and composition in the pasture is to spatially separate clover from grass within the same field. In a field experiment ryegrass and white clover were grown in fine mixtures, and in pure alternating strips of ryegrass and clover of 1.5 m, 3 m or 18 m width within a field. Pastures were grazed for two grazing periods of 9 and 12 weeks, and measurements of sward surface height (SSH), herbage mass and composition and clover morphology were taken. Grazing behaviour was also observed. Results showed that spatial separation in the long term, when compared with a fine mixture, increased clover availability (18% to 30% v. 9%, based on standing dry matter) and was not grazed to extinction. Ewes maintained their preference for clover throughout the experiment (selection coefficient 2 to 5), which resulted in a reduction in the SSH of clover in monocultures to <3 cm and significant changes to the morphology of clover (smaller leaves, shorter petioles and thicker stolon), at the expense of maximising their intake. Spatial separation in the short term may therefore allow grazing animals to select their preferred diet; however, in the long term in continuously grazed pasture, their preference for clover depletes its availability.  相似文献   

10.
This study examined the influence of the following growth factors and cytokines on early embryonic development: insulin-like growth factors I and II (IGF-I, IGF-II), basic fibroblast growth factor (bFGF), transforming growth factor (TGF-β), granulocyte-macrophage colony-stimulating factor (GM-CSF), and leukemia inhibitory factor (LIF). Synthetic oviduct fluid (SOF) was used as the culture medium. We studied the development of bovine embryos produced in vitro and cultured until Day 9 after fertilization. TGF-β1, bFGF, GM-CSF, and LIF used on their own significantly improved the yield of hatched blastocysts. IGF-I, bFGF, TGF-β1, GM-CSF, and LIF significantly accelerated embryonic development, especially the change from the expanded blastocyst to hatched blastocyst stages. Use of a combination of these growth factors and cytokines (GF-CYK) in SOF medium produced higher percentages of blastocysts and hatched blastocysts than did use of SOF alone (45% and 22% vs. 24% and 12%; P < 0.05) on Day 8 after in vitro fertilization and similar results to use of SOF + 10% fetal calf serum (38% and 16%, at the same stages, respectively). The averages of total cells, inner cell mass cells, and trophectoderm cells of exclusively in vitro Day-8 blastocysts for pooled GF-CYK treatments were higher than those for SOF and similar to those for fetal calf serum. The presence of these growth factors and cytokines in the embryo culture medium therefore has a combined stimulatory action on embryonic development; in particular through an increase in hatching rate and in the number of cells of both the inner cell mass and trophoblast. These results are the first to demonstrate that use of a combination of recombinant growth factors and cytokine, as IGF-I, IGF-II, bFGF, TGF-β1, LIF, and GM-CSF, produces similar results to 10% fetal calf serum for the development of in vitro-produced bovine embryos. This entirely synthetic method of embryo culture has undeniable advantages for the biosecurity of embryo transfer.  相似文献   

11.
12.
Reports have demonstrated occurrences of abnormalities in the early stages of chicken embryonic development due to the exposure to electromagnetic fields (EMFs). This article was designed to investigate the effects of sinusoidal EMF on the histopathology, apoptosis, and expressions of c-Fos and β-Catenin genes of the livers of preincubated White Leghorn chicken embryos, based on our published experiments. 300 healthy, fresh fertilized eggs were divided into control (n = 70), sham (n = 70), and four experimental (1–4,days 13, 14, 5, and 19, n = 40) groups. Experimental eggs were exposed to the most effective intensity in a coil with 7.32 mT density, and sham groups were also located in the same coil with no exposure, both for 24 h before incubation. Control, sham, and experimental groups were then incubated in an incubator (37°C, humidity 60%) for 13,14,15, and 19 days. Livers of 13–15 and 19 day-old chicken embryos were removed by C-section and fixed in formalin (10%), stained with Hematoxylin-Eosin and TUNEL for histopathological and apoptosis studies. Others were used for investigating c-Fos and β-Catenin expressions, using RT-PCR. Results showed extensive hemorrhages all over the chicken embryos' bodies and livers, more lymphoid tissues, disturbed parenchymal tissues, sinusoid denaturation, vesiculizad cytoplasm, an increase in the number of apoptotic cells, and a decrease on the levels of expressions of c-Fos and β-Catenin genes in experimental groups of 1–4, comparing control and sham groups.  相似文献   

13.
Reports have demonstrated occurrences of abnormalities in the early stages of chicken embryonic development due to the exposure to electromagnetic fields (EMFs). This article was designed to investigate the effects of sinusoidal EMF on the histopathology, apoptosis, and expressions of c-Fos and β-Catenin genes of the livers of preincubated White Leghorn chicken embryos, based on our published experiments. 300 healthy, fresh fertilized eggs were divided into control (n?=?70), sham (n?=?70), and four experimental (1-4,days 13, 14, 5, and 19, n?=?40) groups. Experimental eggs were exposed to the most effective intensity in a coil with 7.32?mT density, and sham groups were also located in the same coil with no exposure, both for 24?h before incubation. Control, sham, and experimental groups were then incubated in an incubator (37°C, humidity 60%) for 13,14,15, and 19 days. Livers of 13-15 and 19 day-old chicken embryos were removed by C-section and fixed in formalin (10%), stained with Hematoxylin-Eosin and TUNEL for histopathological and apoptosis studies. Others were used for investigating c-Fos and β-Catenin expressions, using RT-PCR. Results showed extensive hemorrhages all over the chicken embryos' bodies and livers, more lymphoid tissues, disturbed parenchymal tissues, sinusoid denaturation, vesiculizad cytoplasm, an increase in the number of apoptotic cells, and a decrease on the levels of expressions of c-Fos and β-Catenin genes in experimental groups of 1-4, comparing control and sham groups.  相似文献   

14.
Triton B catalyzed Michael addition of nitromethane on esters of α,β-unsaturated acids 1 has been studied. The course and regioselectivity of the reaction is discussed in the view of structure of products 2a-g, 3a-g, 4g, f, 5g, f, assessed by GC/MS, NMR and IR spectroscopy and by MOPAC 6 (AM1) calculations, respectively.  相似文献   

15.
The effect of fungi–termite interaction on three rice varieties was conducted in a screen house at the Africa Rice Center (AfricaRice) Ibadan, Nigeria. Of the 10 fungi species (Fusarium verticilloides, Trichoderma sp., Aspergillus niger, Aspergillus flavus, Macrophoma sp., Neurospora sp., Botryodiplodia theobromae, Penicillum sp., Rhizopus sp. and Sclerotium rolfsii) isolated from termites, soil and rice plants, F. verticilloides, Trichoderma sp. and B. theobromae were used for the interaction study. Each fungus was inoculated singly and in combinations with termite into the root of each rice variety in potted soil. Leaf samples were taken to measure the chlorophyll content which is a major parameter to estimate effect of termite–fungi interaction. The chlorophyll content of the inoculated rice plants was significantly reduced when compared with the control. Fungi interaction with termite had significant reduction on the chlorophyll content. The synergistic relationship between the fungi and the termite was discussed.  相似文献   

16.
Recombinant human α-galactosidase A (rhαGal) is a homodimeric glycoprotein deficient in Fabry disease, a lysosomal storage disorder. In this study, each cysteine residue in rhαGal was replaced with serine to understand the role each cysteine plays in the enzyme structure, function, and stability. Conditioned media from transfected HEK293 cells were assayed for rhαGal expression and enzymatic activity. Activity was only detected in the wild type control and in mutants substituting the free cysteine residues (C90S, C174S, and the C90S/C174S). Cysteine-to-serine substitutions at the other sites lead to the loss of expression and/or activity, consistent with their involvement in the disulfide bonds found in the crystal structure. Purification and further characterization confirmed that the C90S, C174S, and the C90S/C174S mutants are enzymatically active, structurally intact and thermodynamically stable as measured by circular dichroism and thermal denaturation. The purified inactive C142S mutant appeared to have lost part of its alpha-helix secondary structure and had a lower apparent melting temperature. Saturation mutagenesis study on Cys90 and Cys174 resulted in partial loss of activity for Cys174 mutants but multiple mutants at Cys90 with up to 87% higher enzymatic activity (C90T) compared to wild type, suggesting that the two free cysteines play differential roles and that the activity of the enzyme can be modulated by side chain interactions of the free Cys residues. These results enhanced our understanding of rhαGal structure and function, particularly the critical roles that cysteines play in structure, stability, and enzymatic activity.  相似文献   

17.
In investigation was conducted annually from 2002 to 2005 between the second week of May and the end of September on the incidence of scarab beetle, Schizonycha ruficollis (Fabricius) in a teak (Tectona grandis L.f.) nursery at Ramdongari, Nagpur, India. The immature stages, that is white grubs of the scarab beetle damaged 14%-52% of teak seedlings in the nursery beds, whereas the adult of the species, that is scarab beetles, were recorded on three new host trees ( Ziziphus xylopyra, Acacia catechu and A. leucophloea) in addition to the reported hosts such as ziziphus (Z. jujuba and Z. mauritiana). Beetles of the S. ruficollis started emerging from the nursery beds just after the pre-monsoon showers and continued for 10-18 days. While beetle of S. ruficollis defoliated tree hosts available in the surroundings, the immature stages of the beetle caused major damage by feeding on root systerfls of teak seedlings with symptoms of wilting and mortality in forest nursery beds. The result of chemical and biological treatments for the management of grubs of S. ruficollis in nursery beds indicated phorate 10% granular at the rate of 20 g/m^2 and chlorpyriphos 20% emulsifiable concentrate at the rate of 5.0 mL/m^2 to be effective. Grubs of S. ruficollis have not been recorded previously as a major pest of teak (T. grandis). This is also the first report on occurrence of S. ruficollis adults on tree hosts such as Z. xylopyra, A. catechu and A. leucophloea. White grubs being pests of economic importance and the toughest insects to manage, information given in this paper on incidence, pest status and management of Schizonycha ruficollis is of importance to researchers and forest nursery managers.  相似文献   

18.
19.
Group-living animals may need to spend less time being vigilant, consequently, having more time for other important activities such as foraging (i.e., group size effect). Przewalski’s gazelle (Procapra przewalskii) is a group-living social animal, and a study was conducted in Qinghai Province of China during June–August 2006 by using a continuous focal sampling method to investigate the influences of group size, sex, within-group spatial position, and nearest-neighbor distance on individual vigilance level (defined as scanning frequency per minute). Male gazelles were more vigilant than females. The gazelle’s vigilance level decreased with group size (group size effect), but only for females. The individuals at the central positions within a group were less vigilant than those at the peripheral positions, but the nearest-neighbor distance did not have any significant influence on the individual vigilance level. Our results support the hypotheses of group size effect and edge effects, but the sexual difference in vigilance level and in the response to group size effect on vigilance suggests that there may be sexual difference in the function and targets of vigilance behavior of Przewalski’s gazelles, which warrants more investigation, with incorporation of within-group spatial position, to better understand the mechanism underlying the group size effect and edge effect.  相似文献   

20.
Analysis of bacterial diversity in soils along the banks of the Solimões and Negro rivers, state of Amazonas, Brazil, was by partial sequencing of the genes codifying the rDNA16S region. Diversity of operational taxonomic units (OTU) and of the divergent sequences obtained were applied in comparative analysis of microbiological diversity in the two environments, based on richness estimators and OTU diversity indices. The higher OTU diversity in the Solimões was based on the higher number of parameters that evoke this. The interaction between the nucleotide sequences of bacteria inhabiting the two riverine environments indicated that the two microrganism communities are similar in composition.  相似文献   

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