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1.
In contradiction to results previously reported, it has been found that DNA prepared by a method which utilizes strong NaOH is acted on by the specific nuclease, although at a rate only 20 per cent. of that of DNA prepared by a milder method. The nature of the changes responsible for the low rate of hydrolysis of the alkali-treated DNA are not known.  相似文献   

2.
硅铁中铁含量的测定方法是:用硝酸、氢氟酸分解试样,冒高氯酸烟驱氟,用氯化亚锡将大量铁还原后,加三氯化钛还原剩余的铁,用稀重铬酸钾氧化过量的还原剂,以二笨胺磺酸钠作指示剂,用重铬酸钾标准溶液滴定。  相似文献   

3.
The total proteins in human urine have been compared by sulfosalicylic acid, sulfosalicylic acid with sodium sulphate and trichloroacetic acid methods with pyrogallol red molybdate method as there are no studies found quantifying imprecision and bias components. Fresh urine of 36 patients was analyzed by four methods. Imprecision and inaccuracy were determined by repeated analysis and method comparison studies using correlation plots, Bland and Altman, and Passing and Bablok regression analyses respectively. The coefficient of variation was 5.07 % for pyrogallol red molybdate; 6.84 % for sulfosalicylic acid; 3.97 % for sulfosalicylic acid with sodium sulphate and 5.93 % for trichloroacetic acid methods. Bland and Altman analysis showed a bias of 5.8, 1.7 and ?5.4 for pyrogallol red molybdate versus sulfosalicylic acid, sulfosalicylic acid with sodium sulphate and trichloroacetic acid methods respectively. Passing and Bablok regression revealed a constant bias for pyrogallol red molybdate versus all turbidimetric methods but a proportional bias only with trichloroacetic acid method. Sulfosalicylic acid with sodium sulphate method is preferred to sulfosalicylic acid and trichloroacetic acid methods.  相似文献   

4.
The cardiac sarcolemma was characterized in 13 normal and 11 ischemic dog hearts by enzyme analysis and compositional assays. Significant decreases in the activities of the sodium-potassium and calcium pumps and structural compositional disturbances were observed in ischemia. High concentrations of oleic acid, a fatty acid and palmitoyl carnitine, a fatty acid intermediate caused inhibition of the enzyme pump activities of the normal sarcolemma. Thus, ischemia results in the functional impairment of the sarcolemma. Accumulation of fatty acid and fatty acid intermediates, occurring in myocardial ischemia, could be an underlying mechanism.  相似文献   

5.
热带假丝酵母(Candida tropicalis)是长碳链二元酸发酵生产中的常用菌种,而热带假丝酵母突变株HP-2-48是一株高产DC12的优良生产菌株。本文对十二碳二元酸的发酵进行了研究,考察了青霉素钠盐、尿素、丙烯酸、pH值对菌体生长、产酸的影响并对其作用机制进行了讨论,并据此建立了长碳链二元酸新的发酵工艺。  相似文献   

6.
模拟酸雨对草甸棕壤中重金属迁移的影响   总被引:14,自引:0,他引:14  
通过室内模拟试验,研究了沈阳地区酸雨对当地草甸棕壤中Cd、Pb、Cu、Zn和As垂直迁移的影响,结果表明,酸雨能促进Cd、Pb、Cu和Zn的迁移,随酸雨酸度增加其促进作用也加强,而且酸雨对Cd、Zn的影响大于Cu、Pb、As的迁移只有在弱酸性酸雨条件下才有增加,在强酸性酸雨条件下,As的迁移受到抑制。  相似文献   

7.
8.
比色法定量测定己酸含量的难点分析及其解决办法   总被引:1,自引:0,他引:1  
吴根福  陈佩华 《科技通报》1995,11(4):198-202
分析了比色法定量测定己酸含量时容量碰到的几个问题,对显色的各个影响因素进行了研究,提出了合理的比色方法,作者认为,只要严格控制稀释液配比和反应液的PH,用比色法定量测定己酸含量是完全可行的。  相似文献   

9.
BackgroundHong Qu glutinous rice wine (HQGRW) is brewed under non-aseptic fermentation conditions, so it usually has a relatively high total acid content. The aim of this study was to investigate the dynamics of the bacterial communities and total acid during the fermentation of HQGRW and elucidate the correlation between total acid and bacterial communities.ResultsThe results showed that the period of rapid acid increase during fermentation occurred at the early stage of fermentation. There was a negative response between total acid increase and the rate of increase in alcohol during the early fermentation stage. Bacterial community analysis using high-throughput sequencing technology was found that the dominant bacterial communities changed during the traditional fermentation of HQGRW. Both principal component analysis (PCA) and hierarchical clustering analysis revealed that there was a great difference between the bacterial communities of Hong Qu starter and those identified during the fermentation process. Furthermore, the key bacteria likely to be associated with total acid were identified by Spearman's correlation analysis. Lactobacillus, unclassified Lactobacillaceae, and Pediococcus were found, which can make significant contributions to the total acid development (| r | > 0.6 with FDR adjusted P < 0.05), establishing that these bacteria can associate closely with the total acid of rice wine.ConclusionsThis was the first study to investigate the correlation between bacterial communities and total acid during the fermentation of HQGRW. These findings may be helpful in the development of a set of fermentation techniques for controlling total acid.How to cite: Liang Z, Lin X, He Z, et al. Dynamic changes of total acid and bacterial communities during the traditional fermentation of Hong Qu glutinous rice wine. Electron J Biotechnol 2020;43. https://doi.org/10.1016/j.ejbt.2019.12.002  相似文献   

10.
A disturbance in the antioxidant defense system including α-tocopherol, ascorbic acid and reduced glutahtione metabolism due to free radical induced oxidative injury has been implicated in various neuro-psychiatric disorders. The roles of these antioxidants, changes in their blood levels and correlation with oxidative stress were studied in a common psychiatric illness Schizophrenia. Fifty-eight subjects of either sex ranging in age from 18–60 years divided into two age groups (≤40 and >40 years) diagnosed for schizophrenia, and forty age and sex-matched normal subjects as controls were included in the study. Blood samples were analyzed for malondialdehyde (MDA), α-tocopherol, total ascorbic acid (TAA), dehydro ascorbic acid (DHAA), reduced ascorbic acid (RAA), leucocyte ascorbic acid (LAA) and reduced glutathione (GSH). A decrease in the levels of α-tocopherol, total ascorbic acid and reduced glutathione was found in schizophrenics compared to normal controls. Further a significant rise in oxidative stress and decreased antioxidant status was observed in the chronic stage of schizophrenia as compared to those in acute condition. A significant rise in dehydroascorbic acid with concomitant fall in reduced ascorbic acid suggests scavenging action of ascorbic acid and its utilization with increased oxidative stress as indicated by high blood malondialdehyde levels. Leucocyte ascorbic acid, a better index of ascorbic acid status was also found to be reduced in schizophrenics, suggesting depletion of body stores of ascorbic acid and the condition worsened with advancing age.  相似文献   

11.
BackgroundCultivated peanut (Arachis hypogaea L.) is a major oilseed crop worldwide. Fatty acid composition of peanut oil may affect the flavor and shelf life of the resulting food products. Oleic acid and linoleic acid are the major fatty acids of peanut oil. The conversion from oleic acid to linoleic acid is controlled by the Δ12 fatty acid desaturase (FAD) encoded by AhFAD2A and AhFAD2B, two homoeologous genes from A and B subgenomes, respectively. One nucleotide substitution (G:C  A:T) of AhFAD2A and an “A” insertion of AhFAD2B resulted in high-oleic acid phenotype. Detection of AhFAD2 mutation had been achieved by cleaved amplified polymorphic sequence (CAPS), real-time polymerase chain reaction (qRT-PCR) and allele-specific PCR (AS-PCR). However, a low cost, high throughput and high specific method is still required to detect AhFAD2 genotype of large number of seeds. Kompetitive allele specific PCR (KASP) can detect both alleles in a single reaction. The aim of this work is to develop KASP for detection AhFAD2 genotype of large number of breeding materials.ResultsHere, we developed a KASP method to detect the genotypes of progenies between high oleic acid peanut and common peanut. Validation was carried out by CAPS analysis. The results from KASP assay and CAPS analysis were consistent. The genotype of 18 out of 179 BC4F2 seeds was aabb.ConclusionsDue to high accuracy, time saving, high throughput feature and low cost, KASP is more suitable for determining AhFAD2 genotype than other methods.  相似文献   

12.
Glycated hemoglobin was estimated by conventional (phenols present before addition of sulphuric acid) and modified (phenols added after dehydration of sugars by the acid), phenol (o-cresol)-sulphuric acid reactions. Even though all the four procedures could differentiate diabetic group from control group, the modified phenol-sulphuric acid method gave the most reliable, absolute values. Glycated hemoglobin levels (moles hydroxymethyl furaldehyde/mole globin) by this method were, 0.34±0.03 for normal subjects (n=20) and 0.62±0.23 for diabetics (n=23). The chemical basis of defects in the other methods is discussed.  相似文献   

13.
Carboxylate-modified gold nanoparticles (GNPs) were synthesized in a simple one-step process based on the reduction of tetrachloroauric acid by aspartic acid in water. GNPs were identified by UV–Vis spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy. Conjugation of protein molecules with functionalized nanoparticles was performed through electrostatic interaction. The GNP–protein conjugates were characterized by gel electrophoresis. The interaction between functionalized GNPs and protein molecules lead to conformational transition of protein structure after conjugation of protein with GNPs. This process was investigated by fluorescence spectroscopy and circular dichroism spectroscopy.  相似文献   

14.
A randomized case control hospital based study was conducted over 12 months time on 31 asphyxiated and 31 normal newborn to see whether urinary uric acid can be used as a marker of perinatal asphyxia and can be correlated with the clinical diagnosis by Apgar score. Uric acid and creatinine were estimated in spot urine within 24 hours after birth in both cases and controls. A ratio between concentrations of uric acid to creatinine was estimated and compared between cases and controls. It was found that the ratios were significantly higher in cases than controls (3.1± 1.3 vs 0.96± 0.54; P < 0.001) and among asphyxia patients, a significant negative linear correlation was found between the uric acid to creatinine ratio and the Apgar score (r = −0.857, P < 0.001). So urinary uric acid to creatinine ratio can be used as an additional non-invasive dispace, easy and at the same time early biochemical marker of birth asphyxia which biochemically supports the clinical diagnosis and severity grading of asphyxia by Apgar score.  相似文献   

15.
The present study was carried out to evaluate the occurrence of association between homocysteine, folic acid and vitamin B(12) in patients with preeclampsia. Fifty preeclamptic patients from gynecology ward were studied for estimation of serum homocysteine, folic acid and vitamin B(12) over a period of October 2007 to June 2010. Serum homocysteine and folic acid, and vitamin B(12) were determined by means of Immulite 1000 analyzer. The statistical analysis of study group of preeclampsia compared with normotensive control group, showed significant alterations in serum homocysteine, folic acid and vitamin B(12) concentrations in preeclampsia. Inverse association between serum homocysteine and folic acid, and vitamin B(12) levels were observed in preeclampsia. The present study found hyperhomocysteinemia and deficiency of folic acid and vitamin B(12) along with increased blood pressure as a risk factor for cardiovascular disease (CVD) in preeclampsia.  相似文献   

16.
建立马尾松松球中总多酚的含量测定方法。以没食子酸为对照品,采用紫外-可见分光光度法测定马尾松松球总多酚的含量。没食子酸在浓度1.818~10.908μg/ml的范围内与吸光度值呈良好的线性关系(r=0.9996),马尾松松球总多酚的平均含量为16.24 mg/g,RSD=0.31%。所建立的方法稳定可靠、操作简便,可作为马尾松松球总多酚的含量测定方法。  相似文献   

17.
An 18kDa protein was identified as a major immunodominant allergen/antigen secreted by a wild type isolate and various clinical isolates ofA. fumigatus. The protein was purified to homogeneity and the N-terminal amino acid was found to be alanine. The N-terminal 20 amino acid sequence of 18kDa was found to be similar to restrictocin, a cytotoxin secreted byAspergillus restrictus. Mass spectroscopic analysis of the purified allergen revealed a molecular size of 17.01 kDa. Immunoreactivity of the purified allergen with monoclonal antibodies and specific IgG and IgE antibodies of the patients of aspergillosis confirmed that this protein is Asp fl.  相似文献   

18.
Folic acid is used for preventing and treating multiple diseases and disorders, administered in the form of oral supplements. The present research work was aimed to study the influence of two non-ionic surfactants Poloxamer and Tween 80 (Polysorbate 80) on pectin submicrospheres formulations. Typical natural polymer pectin was used to encapsulate folic acid by cross linking method. The resultant submicrospheres contributed to improve the aqueous solubility to enhance the bioavailability of folic acid. During investigation, it was observed that pectin polymers influenced kinetics of the rate of reaction more intensively than the surfactants. The physical phenomenon caused the change in their size, shape and chemistry of pectin polymers transforming into submicrospheres in aqueous condition. The characteristic differences of submicrospheres were assessed by scanning electron microscopy, differential scanning calorimetry and Fourier-transform infrared spectroscopy. The average diameters of the submicrospheres ranged between 250 and 500 nm. The encapsulation efficiency of submicrospheres ranged between 80 and 96 %. The characteristic swelling behavior of lyophilized submicrospheres was influenced by the ratio of pectin polymers and folic acid used in the formulations. The submicrospheres systems exhibited controlled release of folic acid due to the pH-dependent solubility of pectin polymers in aqueous medium. The submicrospheres showed good haemocompatibility suggesting them to be promising candidates for oral delivery.  相似文献   

19.
Uric acid in urine was analyzed using porcine liver uricase and horseradish peroxidase immobilized on alkylamine and arylamine glass beads (pore diameter 55nm) respectively. The minimum detection limit was 5.0mg/0.1 ml urine. The recovery of added uric acid was 92%. Within and between assay CVS were <1.3% and <5.3% respectively. A good correlation (r=0.93) was found between urinary urate values obtained by a commercial kit method and the present method. The uric acid in 24hr urine of apparently healthy adults and person sufering from various diseases was found to be 450 to 900mg/24hr, 659mg/24hr (range, mean) and 910–1400mg/24hr, 1145 mg/24hr (range, mean) respectively with the present method.  相似文献   

20.
以盐酸、硝酸对镍铁合金进行分解试样,高氯酸除碳及氧化杂质元素,氢氟酸挥硅,以柠檬酸三钠为掩蔽剂,在碱性条件下(Ph8~9),用丁二酮肟络合镍元素生成稳定的沉淀,该沉淀经120℃烘干后称量得出镍含量。本方法操作简单,分析速度快,结果准确,且分析成本低,适合开展大批量样品的高效分析。  相似文献   

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