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11.
Portulaca oleracea leaves were found to contain 0.42% of a mucilage mixture. The mucilage was fractionated into an acidic and a neutral fraction. The acidic fraction consists of galacturonic acid residues joined by α-(1→4)-linkages; 60% of these residues are present as the calcium salt, and esterified galacturonic acid residues are absent. The neutral fraction is composed of 41% of arabinose and 43% of galactose residues, besides traces of rhamnose residues. 相似文献
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M. Metwally M. el Sayed M. Osman P. P. F. Hanegraaf A. H. Stouthamer H. W. van Verseveld 《Antonie van Leeuwenhoek》1991,59(1):35-43
Aspergillus niger has been grown in glucose- and maltose-limited continuous cultures to determine the bioenergetic consequences of the production of the extracellular enzyme glucoamylase. Growth yields (g biomass per mol substrate) were high, indicating that growth was very efficient and protein production for biomass was not exceedingly energy consuming. It has been found that the energy costs for the production of this extracellular enzyme is very high. Depending on the efficiency of energy conservation the glucoamylase protein yield on ATP is between 1.3 and 2.6 g protein per mol ATP, which is equal or less than 10% of the theoretical maximum of 25.5. These high energy costs most probably have to be invested in the process of excretion. A comparison between an industrial over-producing strain and the wild typeAspergillus niger showed that this over-producing strain most probably is a regulatory mutant. Two regions of specific growth rates could be determined (one at specific growth rates lower and one at specific growth rates higher than 0.1 h-1), which are characterized by differences in mycelium morphology and a significant deviation from linearity in the linear equation for substrate utilization. Analysis of the region of specific growth rates higher than 0.1 h-1 yielded maintenance requirements of virtual zero. It has been concluded that for a good analysis of the growth behaviour of filamentour fungi the linear equation for substrate utilization is not suitable, since it contains no term for the process of differentiation. 相似文献
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Summary The course of the CO2 evolution rates of soil samples has been followed continuously in the absence and in the presence of various organic compounds. After an incubation period of 300 hours at 13 and 20°C the CO2 evolution from pasture soil (containing 1.76% soil organic carbon) amounted to 0.13 and 0.44g CO2–C.g soil–1.h–1, respectively. For arable soil (containing 1.20% soil organic carbon) the rates amounted to 0.04 and 0.09 g CO2–C.g soil–1.h–1, respectively.At 20°C larger amounts of the organic substrates added to the soil supplied with 20 g NH4NO3–N.g soil–1 were lost as CO2 than at 13°C, indicating a higher efficiency of the growth of microorganisms at lower temperatures. In the absence of NH4NO3 the respiration rates were initially higher than in its presence, suggesting that a part of the soil microflora is inhibited by low concentrations of NH4NO3. The amounts of carbon lost were low for phenolcarboxylic acids with OH groups in the ortho position. The replacement of one of these groups by a methoxyl group resulted in a larger amount of the C lost as CO2. The replacement of the COOH group by a C=C–COOH group had a decreasing effect on the decomposition of the phenolic acids tested. The decomposition of vanillic acid,p-hydroxybenzoic acid, and of the benzoic acids with OH groups in the meta position was as complete as that of glucose, amino acids or casein. The decomposition of bacterial cells to CO2 was considerably less than that of glucose.No evidence could be obtained that the low percentage of substrate converted to CO2 at the time of maximal respiration rate was due to the decreasing diffusion rate of substrate to the microbial colonies in the soil during the consumption of substrate. 相似文献
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The 1-methyl derivatives (3 and 4) of 3-(1-phenyl- (1) and 3-(1-p-bromophenylhydrazono-L-threo-2,3,4-trihydroxybutyl)-2-quinoxalinone (2) were prepared by methylation. Periodate oxidation of 3 gave 1-methyl-3-[1-(phenylhydrazono)glyoxal-1-yl]-2-quinoxalinone (5), which, on reduction with sodium borohydride, gave the corresponding 3-[2-hydroxy-1-(phenylhydrazono)ethyl] derivative (8). Reaction of 5 with hydroxylamine or benzoylhydrazine gave the corresponding 2-oxime (6) and 2-(benzoylhydrazone) (7), respectively. Acetic anhydride causes one molecule of 3 or 4 to undergo elimination of two molecules of water, with simultaneous acetylation and ring closure to afford pyrazoles 9 and 10, respectively. Pyrolysis of the triacetate of 3 led to the elimination of acetic acid from the sugar and the hydrazone residue, to give the 3-[5-(acetoxymethyl)-1-phenylpyrazol-3-yl] derivatives (9). Acetic acid was found to effect the same rearrangement, but without acetylation, of 1, 2, and 3 to give the 3-[5-(hydroxymethyl)] derivatives 11, 12, and 13, respectively. The structure of these pyrazoles was confirmed by a series of reactions, including methylation and acetylation. The n.m.r. and i.r. spectra of the compounds were investigated. 相似文献
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Sayed Sifat Bin Nain Zulkar Khan Md. Shakil Ahmed Abdulla Faruq Tasmin Rubaia Adhikari Utpal Kumar 《International journal of peptide research and therapeutics》2020,26(4):2089-2107
International Journal of Peptide Research and Therapeutics - Lassa virus (LASV) is responsible for a type of acute viral haemorrhagic fever referred to as Lassa fever. Lack of adequate treatment... 相似文献
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Robert Mason Helen C. Dearden Bella Nguyen Jennifer A. Soon Jessica Louise Smith Manreet Randhawa Andrew Mant Lydai Warburton Serigne Lo Tarek Meniawy Alexander Guminski Phillip Parente Sayed Ali Andrew Haydon Georgina V. Long Matteo S. Carlino Michael Millward Victoria G. Atkinson Alexander M. Menzies 《Pigment cell & melanoma research》2020,33(2):358-365
The combination of ipilimumab and nivolumab is a highly active systemic therapy for metastatic melanoma but can cause significant toxicity. We explore the safety and efficacy of this treatment in routine clinical practice, particularly in the setting of serine/threonine‐protein kinase B‐Raf (BRAF)‐targeted therapy. Consecutive patients with unresectable stage IIIC/IV melanoma commenced on ipilimumab and nivolumab across 10 tertiary melanoma institutions in Australia were identified retrospectively. Data collected included demographics, response and survival outcomes. A total of 152 patients were included for analysis, 39% were treatment‐naïve and 22% failed first‐line BRAF/MEK inhibitors. Treatment‐related adverse events occurred in 67% of patients, grade 3–5 in 38%. The overall objective response rate was 41%, 57% in treatment‐naïve and 21% in BRAF/MEK failure patients. Median progression‐free survival was 4.0 months (95% CI, 3.0–6.0) in the whole cohort, 11.0 months (95% CI, 6.0‐NR) in treatment‐naïve and 2.0 months (95% CI, 1.4–4.6) in BRAF/MEK failure patients. The combination of ipilimumab and nivolumab can be used safely and effectively in a real‐world population. While first‐line efficacy appears comparable to trial populations, BRAF‐mutant patients failing prior BRAF/MEK inhibitors show less response. 相似文献