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1.
The pools of free ribose 1-phosphate and deoxyribose 1-phosphate have been measured in Bacillus cereus. It is shown that crude extracts of the same organism can actively utilize the sugar phosphates to convert adenine to ATP and deoxyATP, via a ‘salvage’ pathway, involving adenine ribosylation (or deoxyribosylation), followed by multiple phosphorylation steps. The biosynthetic pathway operates even in the presence of excess Pi, thus showing that purine nucleoside phosphorylases may function in vivo, contrary to what is generally assumed, as anabolic rather than catabolic enzymes.  相似文献   

2.
通过对旱地甜菜叶片生长特性及摘除不同叶组对块根产量,含糖量,显微结构的影响研究,结果表明:甜菜第10-20片叶的叶龄最长,积温最高,是甜菜的主要功能叶;甜菜从第20片叶期起进入块根,糖份增长期,从第55叶期起进入糖份积累期;摘除不同叶组的叶片对甜菜块根产量,含糖量及显微结构均有不同程度降低作用,摘除前期叶组对甜菜块根产量,产糖量,根径减幅较大,摘除后期叶组对块根含糖量,维管束环数,维管束环密度减幅较大;摘除第1-30片叶对甜菜影响最大。  相似文献   

3.
A batch reactor was used to investigate the dilute acid hydrolysis reaction of alpha-cellulose and sugar decomposition reactions. Varying the sulfuric acid concentration from 0.07 to 5.0% for reaction temperatures between 180 and 220°C significantly affected glucose yields, which ranged from about 70% to below 10%. Increasing the reaction temperature enhanced this effect. Similar experimental results were obtained for the decomposition of xylose. For sugar decomposition reactions, less than 0.3 g/L of furfural and 5-hydroxymethylfurfural (5-HMF) were produced from glucose and xylose in the absence of sulfuric acid at 190°C and 15 min of reaction time, but adding a small amount of sulfuric acid (0.5%) dramatically increased the decomposition rate and led to the formation of four undesireable products: formic acid, 5-HMF, acetic acid, and furfural. In both hydrolysis and fermentation reactions formic acid, acetic acid, and 5-HMF severely inhibited ethanol fermentation, while furfural had less of an inhibition effect.  相似文献   

4.
This study examines the influence of ensiled sugar beets (Beta vulgaris ssp. vulgaris) on preference and short-time dry matter (DM) intake of goats. Whole sugar beets were ensiled either without any silage additive (sugar beet silage (SBS)) or with a chemical additive (6 l/t) containing 85% formic and propionic acids (treated sugar beet silage (TBS)) and were chopped after ensiling. The influence of different proportions of SBS (0%, 6.25%, 12.5%, 18.75% and 25% of dietary DM) and TBS (0%, 5%, 10%, 15% and 20% of DM) in partial mixed rations on short-time DM intake by goats (adult Saanen type wethers; n = 10) was studied in two separate, independent trials. Preference behaviour was investigated by offering the goats two different experimental diets per day and offer each possible combination of them (n = 10) once throughout the trial. On this basis, the mean DM intake (within 30 min and 3 h) of each experimental diet was determined. Both sugar beet silages showed good fermentation quality with low pH. By using the chemical silage additive, the production of ethanol was reduced and considerable amounts of sugar were preserved. In the short-term preference experiment, increasing concentrations of sugar beet silage in the ration increased DM intake (p < 0.05) in a linear way with a strong preference for those diets containing high amounts of sugar beet silage. Initial DM intake after 30 min was 4–5 fold increased for diets containing the highest beet concentration. It is assumed that the preference was positively influenced by sugar and sweet taste or the associated higher concentration of metabolisable energy.  相似文献   

5.
The effect of cyclic nucleotides and cholera toxin on the phosphorylation of the brush border membrane proteins of the rat jejunum was studied. Phosphorylation was analyzed by autoradiography of brush border membrane proteins separated by SDS-polyacrylamide gel electrophoresis. Phosphorylation was performed either in vivo by perfusion of the jejunum with [32P]orthophosphate followed by an analysis of the isolated membranes or in vitro by phosphorylation of isolated brush border membranes by [γ-32P]ATP in the presence of saponin. The addition of cholera toxin (10 μg/ml) or dibutyryl-cAMP (5 mmol/l) to the perfusate was unable to produce significant changes in the phosphoprotein pattern. On the other hand, cAMP (at 5 μmol/l) induced an increase of the phosphorylation of a 86 kDa protein when freshly isolated brush border membranes were phosphorylated by [γ-32P]ATP. However, the same effect could also be induced by low concentrations of cGMP (0.1 μmol/l). It is concluded that brush border membranes from rat jejunum do not contain cAMP-dependent protein kinase activity and that cAMP-dependent protein phosphorylation of this membrane does probably not represent the final event of cholera toxin-induced secretion.  相似文献   

6.
Uridine 5′‐diphosphate (UDP)‐glucose is transported into the lumen of the endoplasmic reticulum (ER), and the Arabidopsis nucleotide sugar transporter AtUTr1 has been proposed to play a role in this process; however, different lines of evidence suggest that another transporter(s) may also be involved. Here we show that AtUTr3 is involved in the transport of UDP‐glucose and is located at the ER but also at the Golgi. Insertional mutants in AtUTr3 showed no obvious phenotype. Biochemical analysis in both AtUTr1 and AtUTr3 mutants indicates that uptake of UDP‐glucose into the ER is mostly driven by these two transporters. Interestingly, the expression of AtUTr3 is induced by stimuli that trigger the unfolded protein response (UPR), a phenomenon also observed for AtUTr1, suggesting that both AtUTr1 and AtUTr3 are involved in supplying UDP‐glucose into the ER lumen when misfolded proteins are accumulated. Disruption of both AtUTr1 and AtUTr3 causes lethality. Genetic analysis showed that the atutr1 atutr3 combination was not transmitted by pollen and was poorly transmitted by the ovules. Cell biology analysis indicates that knocking out both genes leads to abnormalities in both male and female germ line development. These results show that the nucleotide sugar transporters AtUTr1 and AtUTr3 are required for the incorporation of UDP‐glucose into the ER, are essential for pollen development and are needed for embryo sac progress in Arabidopsis thaliana.  相似文献   

7.
Calcium chloride concentrations from 0.0 to 12.12 mM were added to the culture medium and calcium content in calluses were determined directly by X-ray fluorescence spectrometry, a non-destructive method, allowing the processing of the same tissue for histological analysis. A multivariate statistical analysis (PCA – Principal Components Analysis) grouped the treatments into 5 blocks and indicated the most responsive group. Lack of calcium supply caused a complete absence of a morphogenic process and tissue collapse. An increase in calcium concentration gave higher total protein and sugar contents, an increase in peroxidase specific activity and changes in the histological characteristics. It was possible to verify that calcium stimulated globular somatic embryo formation at concentration of 6.62 mM. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

8.
Nucleotide sugar transporters, encoded by the SLC35 gene family, deliver nucleotide sugars throughout the cell for various glycosyltransferase-catalyzed glycosylation reactions. GlcNAc, in the form of UDP-GlcNAc, and galactose, as UDP-Gal, are delivered into the Golgi apparatus by SLC35A3 and SLC35A2 transporters, respectively. However, although the UDP-Gal transporting activity of SLC35A2 has been clearly demonstrated, UDP-GlcNAc delivery by SLC35A3 is not fully understood. Therefore, we analyzed a panel of CHO, HEK293T, and HepG2 cell lines including WT cells, SLC35A2 knockouts, SLC35A3 knockouts, and double-knockout cells. Cells lacking SLC35A2 displayed significant changes in N- and O-glycan synthesis. However, in SLC35A3-knockout CHO cells, only limited changes were observed; GlcNAc was still incorporated into N-glycans, but complex type N-glycan branching was impaired, although UDP-GlcNAc transport into Golgi vesicles was not decreased. In SLC35A3-knockout HEK293T cells, UDP-GlcNAc transport was significantly decreased but not completely abolished. However, N-glycan branching was not impaired in these cells. In CHO and HEK293T cells, the effect of SLC35A3 deficiency on N-glycan branching was potentiated in the absence of SLC35A2. Moreover, in SLC35A3-knockout HEK293T and HepG2 cells, GlcNAc was still incorporated into O-glycans. However, in the case of HepG2 cells, no qualitative changes in N-glycans between WT and SLC35A3 knockout cells nor between SLC35A2 knockout and double-knockout cells were observed. These findings suggest that SLC35A3 may not be the primary UDP-GlcNAc transporter and/or different mechanisms of UDP-GlcNAc transport into the Golgi apparatus may exist.  相似文献   

9.
银杏萜内酯的分布与矮壮素对其生物合成的调节   总被引:5,自引:0,他引:5  
银杏萜内酯分为银杏内酯A、B、C、J、M(ginkgolide A、B、C、J、M)和白果内酯(bilobalide),主要存在于银杏叶与根内,近年的研究指出银杏萜内酯分别在银杏叶和根中生物合成[1],Cartayrade等人[2]通过叶片生根实验发现生根叶片的银杏萜内酯含量显著高于未生根叶,因而认为银杏萜内酯是在根部合成,然后运输到叶中积累,目前对此还缺乏进一步的研究报道.  相似文献   

10.
Rhynchophylline and isorhynchophylline are major tetracyclic oxindole alkaloid components of Uncaira species, which have been long used as medicinal plants. In this study we examined the protective effects of rhynchophylline and isorhynchophylline on in vitro ischemia-induced neuronal damage in the hippocampus and interaction of these alkaloids with neurotransmitter receptors in a receptor expression model of Xenopus oocytes. In vitro ischemia was induced by exposing the hippocampal slices to oxygen- and D-glucose-deprived medium over 8 min. The resultant neuronal damage was elucidated as deterioration of population spike (PS) amplitudes evoked trans-synaptically by electrical stimulation of Schaffer collaterals and recorded in the CA1 area. Rhynchophylline and isorhynchophylline, as well as the N-methyl-D-aspartate (NMDA) antagonist (+/-)-2-amino-5-phosphono-valeric acid (APV), the muscarinic M1 receptor antagonist pirenzepine, and the 5-HT2 receptor antagonist ketanserin, attenuated the in vitro ischemia-induced neuronal damage in a concentration-dependent manner. There was no difference in the extent of protection against the neuronal damage between rhynchophylline and isorhynchophylline treatment. In Xenopus oocytes expressing the rat brain receptors encoded by total RNA, both rhynchophylline and isorhynchophylline reduced muscarinic receptor- and 5-HT2 receptor-mediated current responses in a competitive manner. Together with our previous findings that rhynchophylline and isorhynchophylline have a non-competitive antagonistic effect on the NMDA-type ionotropic glutamate receptors, the present results suggest that these alkaloids exert their protective action against ischemia-induced neuronal damage by preventing NMDA, muscarinic M1, and 5-HT2 receptors-mediated neurotoxicity during ischemia.  相似文献   

11.
目的观察苦参、当归、侧柏叶和白鲜皮及观察苦参、当归、侧柏叶和白鲜皮、混合药液与主要有效成分对4株CBS马拉色菌标准株的体外抑菌效果。方法通过液基稀释法,用含橄榄油的液体培养基测定各药液对马拉色菌的抑制作用。结果最小抑菌浓度(MIC)由小到大排列分别为:白鲜碱、苦参碱、苦参、侧柏叶、氧化苦参碱、侧柏叶+当归(二仙丸)、混合药液(侧柏叶+当归+苦参+白鲜皮)、白鲜皮、二仙丸+苦参、苦参+白鲜皮、二仙丸+白鲜皮、槲皮素、当归、阿魏酸。结论4种中草药及其混合药液、主要有效成分均有抑制马拉色菌的作用。  相似文献   

12.
Drug resistance in Candida species has been considerably increased in the last decades. Given the opposition to antifungal agents, toxicity and interactions of the antimicrobial drugs, identifying new antifungal agents seems essential. This study assessed the antifungal effects of nanoparticles (NPs) on the standard strains of Candida albicans and Candida glabrata and determined the expression genes, including ERG3, ERG11 and FKS1. Selenium nanoparticles (Se-NPs) were biosynthesized with a standard strain of C. albicans and approved by several methods including, ultraviolet-visible spectrophotometer, X-ray diffraction technique, Fourier-transform infrared analysis, field-emission scanning electron microscopy and EDX diagram. The antifungal susceptibility testing performed the minimum inhibitory concentrations (MICs) using the CLSI M27-A3 and M27-S4 broth microdilution method. The expression of the desired genes was examined by the real-time PCR assay between untreated and treated by antifungal drugs and Se-NPs. The MICs of itraconazole, amphotericin B and anidulafungin against C. albicans and C. glabrata were 64, 16 and 4 µg ml−1. In comparison, reduced the MIC values for samples treated with Se-NPs to 1 and 0·5 µg ml−1. The results obtained from real-time PCR and analysis of the ∆∆Cq values showed that the expression of ERG3, ERG11 and FKS1 genes was significantly down-regulated in Se-NPs concentrations (P < 0·05). This study's evidence implies biosafety Se-NPs have favourable effects on the reducing expression of ERG3, ERG11 and FKS1 antifungal resistance genes in C. albicans and C. glabrata.  相似文献   

13.
The level of cytochrome b5A ( CYB5A ) in pig testis is correlated with boar taint from androstenone and an AF016388:c.-8G>T polymorphism in CYB5A has been linked with low androstenone levels in the fat of pigs. In this study, we developed a polymerase chain reaction-based assay to genotype 1242 boars from eight lines for the c.-8G>T SNP. The c.-8T allele was found in all eight lines at a frequency ranging from 1.8% to 20.3% with an overall frequency of 8.6%. Significant deviations from Hardy–Weinberg equilibrium were found in the Hampshire, Landrace and Yorkshire breeds. The homozygous mutant c.-8TT occurred infrequently and was not found in some lines, but was consistently associated with low androstenone levels in fat. Both CYB5A mRNA and CYB5A protein levels were decreased in the c.-8TT genotype in a subset of Yorkshire boars, suggesting that low levels of CYB5A protein in the c.-8TT mutant were not due to inefficient translation of CYB5A mRNA. There were significant but modest marker effects on fat androstenone levels in Landrace, Yorkshire and a Large White/Duroc cross and fat skatole in Duroc and Sire Line breeds. There was no effect of CYB5A genotype on bulbourethral gland length, suggesting that this SNP will not affect reproductive traits. We conclude that the c.-8G>T SNP in the CYB5A gene has a significant but modest effect on boar taint in male pigs and could be useful in some breeds as part of a panel of SNP markers in a marker-assisted selection programme to produce low boar taint pigs.  相似文献   

14.
The inhibition and activation effects of some drugs on the activities of superoxide dismutase enzymes (SOD) in human erythrocyte and leukocyte cells was investigated. Firstly, CuZnSOD enzyme was purified 837–fold and 12% efficiency from human erythrocytes by ethanol-chloroform treatment to remove hemoglobin and then ion exchange chromatography (DEAE-Sepharose) and copper chelate affinity chromatography techniques. Inhibition or activation effects of fourteen drugs on CuZnSOD was investigated. None of the studied drugs except for 5-fluorouracil showed any effects on the enzyme. 5-fluorouracil showed activation effects on CuZnSOD at 3.33 mg/ml and 4 mg/ml concentrations with 33% and 32% activation, respectively. Leukocytes were isolated from healthy human blood, lysed in liquid nitrogen and the effect of 5-fluorouracil on the lysate SOD activity investigated. 5-Fluorouracil showed inhibition effects on total SOD activity of human leukocytes at 2 mg/ml and 4 mg/ml concentrations with 42% and 62% inhibition, respectively.  相似文献   

15.
A methanolic extract of dried leaves of Polygala japonica Houtt (Polygalaceae) significantly attenuated nitric oxide production in lipopolysaccharide-simulated BV2 microglia. Five anthraquinones chrysophanol (1), emodin (2), aloe-emodin (3), emodin 8-O-β-D-glucopyranoside (4) and trihydroxy anthraquinone (5), and four flavonoids kaempferol (6), chrysoeriol (7), kaempferol 3-gentiobioside (8) and isorhamnetin (9) were isolated from the methanolic extract using bioactivity-guided fractionation. Among them, compounds 14, 6 and 7 showed significant inhibitory effect on lipopolysaccharide-induced nitric oxide production in BV2 microglia at the concentrations ranging from 1.0 to 100.0 μM.  相似文献   

16.
In situ and in vitro experiments were carried out to determine the effect of various composts (leafy fruit compost (LFC), garden compost (GC), and crops compost (CC)) and their water extract on Pythium debaryanum, Fusarium oxysporum f.sp. lycopersici, Sclerotium bataticola. Compost water extract (CWE) of LFC, GC, and CC were found to contain Bacillus spp., Micrococcus spp., Staphylococcus spp. and Corynebacterium spp., and the fungi Aspergillus spp., Rhizopus spp., and Drechslera spp., and various Actinomycetes. In situ results indicated considerable decrease in fungal growth around the unautoclaved compost especially in the case of S. bataticola and F. oxysporum f.sp. lycopersici, compared to the autoclaved compost. In vitro tests showed that concentration of CWE at 5, 10 and 15% (v/v) suppressed the hyphal growth of S. bataticola by 83% using 5% CC and by 94.4% using 5% LFC or 10% GC, and F. oxysporum f.sp. lycopersici by 94.4% using either composts. CWE of GC decreased fungal dry weight of F. oxysporum f.sp. lycopersici by 97.7%, P. debaryanum by 92.8%, and S. bataticola by 84.4%; CC decreased F. oxysporum f.sp. lycopersici by 94%, P. debaryanum by 86.2%, and S. bataticola by 63.3%, while CWE of LFC was the least effective against the tested fungi. CWE produced clear inhibition zones against all the tested fungi. Microflora found in CWE have an important role in suppressing the growth of tested fungi. CWE contained neither antibiotics nor siderophores. The presence of protease, chitinase, lipase and -1,3 glucanase (lysogenic enzymes) in CWE indicates a possible role in fungal degradation.  相似文献   

17.
Chronic wounds such as diabetic ulcers are a serious public health problem. Extensive research is needed to find new alternatives for wound treatment. Photodynamic therapy (PDT) is a non-invasive method, which has been studied for several decades to treat cancer, infections, and other diseases. PDT involves the administration of a photosensitizer compound followed by irradiation with using light at specific wavelength to produce reactive oxygen species (ROS) using molecular oxygen. It is possible that low dose photodynamic therapy (LDPDT) could improve wound healing and stimulates the cell repair process. This study we explored the effect of LDPDT on wound healing in vitro using normal and diabetic cellular wound models. The effects of different concentrations of 5-ALA and different energy densities (dark or light) on the cell viability of human fibroblast cells were studied using the MTT assay. After ascertaining the optimum parameters, a scratch wound assay was performed on both normal and diabetic cells and then cells treated with 1 and 5 μg/mL of 5-ALA at 1 J/cm2 energy density. ROS production and morphological alteration of the cells were studied. The mortality of normal fibroblast cells increased with increasing 5-ALA concentration and also increasing energy density (up to 3 J/cm2). However, in diabetic cells, the mortality rate did not decrease. Diabetic cells showed increased migration and closure of the scratch compared to normal cells under similar conditions. A low concentration of 5-ALA (5 μg/mL) and low energy density of 1 J/cm2 in both normal and diabetic cells gave a small increase in ROS levels compared to controls. This may explain the positive effects of LDPDT on wound healing. The findings of this study suggest that LDPDT may have a potential effect on the wound healing of diabetic wounds.  相似文献   

18.
B K Vig 《Mutation research》1979,61(2):309-317
Chinese hamster cells, M-3, were treated with BLM (1--4 micrograms/ml) for 30 min to 1 h at 37 degrees or 43 degrees C. After treatment, the cells were reincubated at 37 degrees until recovery. The material treated at 43 degrees showed increased damage expressed as chromosome and chromatid-type breaks and exchanges. Since the amount of BLM entering the cell at 37 degrees is supposedly similar to that which enters the cell at 43 degrees, the enhanced damage is the result of true synergism, and not the facilitation of the drug's entry into the cell.  相似文献   

19.
The effect of DL-propranolol on 3′,5′-diethoxycarbonyl-1,4-dihydrocollidine-induced experimental porphyria was studied.dl-Propranolol, a beta-adrenergic blocking agent with non-specific membrane effects, partially inhibited 3′,5′-diethoxycarbonyl-1,4-dihydrocollidine-induced delta-aminolevulinate synthetase activity both in rats and in chick embryo liver cells in culture.In rats, DL-propranolol decreased urinary delta-aminolevulinate and porphobilinogen but no change occurred in the 24-h urinary excretion of total porphyrins and in the concentration of porphyrins in the liver. In cultured chick embryo liver cells treated with 3′,5′-diethoxycarbonyl-1,4-dihydrocollidine, DL-propranolol decreased accumulation of porphyrins in the medium.d-Propranolol, oxprenolol and quinidine acted like dl-propranolol in chick embryo liver cells in culture treated with 3′,5′-diethoxycarbonyl-1,4-dihydrocollidine. Pindolol, practolol and lidocaine had no effect.Phenobarbitone had a synergistic effect on the induction of delta-aminolevulinate synthetase by 3′,5′-diethoxycarbonyl-1,4-dihydrocollidine in cultures of chick embryo liver cells. This induction was partially inhibited by propranolol. However, the increased accumulation of porphyrins in the medium caused by 3′,5′-diethoxycarbonyl-1,4-dihydrocollidine was inhibited by the addition of phenobarbitone. This inhibited induction was further decreased by propranolol.Most of our results indicate that the drugs tested act mainly by their effects on membranes.  相似文献   

20.
Diapause hormone (DH) and pheromone biosynthesis activating neuropeptide (PBAN) are encoded by a single mRNA in the suboesophegeal ganglion (SG) and are responsible for induction of embryonic diapause in Bombyx mori and sex pheromone biosynthesis in lepidopteran insects. PBAN cDNA analyses revealed that the DH-like peptide is present in several species that have a pupal diapause. However, the function of the DH-like peptide remains unknown. In the present study, we cloned the cDNA encoding DH-PBAN in Helicoverpa armigera utilizing the rapid amplification of the cDNA ends method. The nucleotide se quence analysis revealed that the longest open reading frame of this cDNA encodes a 194-amino acid precursor protein that con tains a 33-aa PBAN, a 24-aa DH-like peptide, and three other neuropeptides, all of which have a common C-terminal pentapeptide motif FXPR/KL ( X=G, T, S). A homology search showed that H. armigera DH-like and PBAN are highly homologous to those from other insects. Northern blot analysis demonstrated a single message RNA corresponding to the size of Har-DH-PBAN cDNA from pupal SG with significantly higher expression in the SG of nondiapause pupae than diapausing pupae. Western blot analysis showed DH-like peptide expression from SG of both males and females. When DH-like peptide was injected into nondiapause larvae and pupae, it did not induce diapause, but rather efficiently broke pupal diapause in H. armigera. The ED(50) of DH to terminate pupal diapause is 20 pmol/pupae. The other four FXPRLamide neuropeptides from the DH-PBAN polyprotein precursor have cross activity for diapause termination. These observations therefore suggest a potential role for these FXPRL family peptides in promoting continuous development in several noctuid species. The high expression of this gene in pharate adults and adults indicates that the FXPRL family peptides may have multiple physiological functions.  相似文献   

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