木质纤维素类生物质酸水解研究进展

木质纤维素中纤维素和半纤维素经酸水解可转化为糖,糖进一步可生产燃料乙醇和其他化工产品。因此,木质纤维素酸水解制备糖是纤维素转化过程中关键步骤。本文综述了硫酸、盐酸、硝酸、磷酸、马来酸等无机、有机酸水解木质纤维素类生物质研究进展,对各种酸水解工艺的优缺点进行了分析和比较,指出了木质纤维素类生物质酸水解的研究方向。     

Metabolism of 3 beta-hydroxycholest-5-en-26-oic acid in hamsters

Metabolism of 26-hydroxycholesterol to 3 beta-hydroxychol-5-en-24-oic acid and other C24-bile acids has been expected to occur by way of 3 beta-hydroxycholest-5-en-26-oic acid in studies in vitro. 3 beta-Hydroxycholest-5-en-26-oic acid was infused intravenously into bile fistula hamsters and the following C24-bile acids were identified: 3 beta-hydroxychol-5-en-24-oic acid, lithocholic acid, chenodeoxycholic acid, and a small amount of cholic acid.     

Über die Grenzen der metabolischen Adaptationsfähigkeit vonAspergillus niger

Summary The ability ofA. niger to assimilate malonic acid, which we consider to be the way both of obtaining energy (citric acid cycle) and of synthesizing cell substances (glyoxylic acid cycle), is reduced by substitution. While methyl malonic acid is quickly assimilated and ethyl malonic acid more slowly propyl-, dimethyl-, and diethyl malonic acid cannot be used by already formed molds.     

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin from Salmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (BCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.     

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

Summary The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin fromSalmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (GCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.     

Comparative oxidation of erucic and oleic acids by mitochondria isolated from heart auricle of living man]

Mitochondria were isolated from fragments of heart auricles, that were cut off during surgical intracardiac operations. They were incubated with either [14 14C] erucic acid or [10 14C] oleic acid as a control. In the experimental conditions used, the radioactive products soluble in perchloric acid, that are issued from the beta-oxidation reactions in mitochondria, were formed in much lower amounts from erucic acid than from oleic acid. These results show the very low capacity of human heart mitochondria to use directly erucic acid as a substrate for energy requirements, as has been observed before with other animal species. Activation of fatty acids, the preliminary step of their beta-oxidation, was also observed to be very much lower with erucic acid.     

Les glycoprotéines sériques dans le granulome expérimental provoqué par la carrageenine

Summary We studied serum glycoproteins in rats and guinea pigs during the development of granulomas, provoked by carrageenin injection. In rats total serum sialic acid was raised as well as sialic acid soluble in sulfosalicylic acid and haptoglobin. The rise of these 2 fractions, seromucoid and haptoglobine accounts quantitatively for the rise of the total sialic acid. In guinea pigs total serum sialic acid was unchanged, but sulfosalicylosoluble sialic acid as well as haptoglobin were much higher than basal values. Quantitatively the serum glycoprotein reaction was much higher in rats than in guinea pigs.     

Phytanic acid impairs mitochondrial respiration through protonophoric action

Refsum disease is a rare, inherited neurodegenerative disorder characterized by accumulation of the dietary branched-chain fatty acid phytanic acid in plasma and tissues caused by a defect in the alphaoxidation pathway. The accumulation of phytanic acid is believed to be the main pathophysiological cause of the disease. However, the exact mechanism(s) by which phytanic acid exerts its toxicity have not been resolved. In this study, the effect of phytanic acid on mitochondrial respiration was investigated. The results show that in digitonin-permeabilized fibroblasts, phytanic acid decreases ATP synthesis, whereas substrate oxidation per se is not affected. Importantly, studies in intact fibroblasts revealed that phytanic acid decreases both the mitochondrial membrane potential and NAD(P)H autofluorescence. Taken together, the results described here show that unesterified phytanic acid exerts its toxic effect mainly through its protonophoric action, at least in human skin fibroblasts. Received 4 August 2007; received after revision 26 September 2007; accepted 10 October 2007 J. C. Komen, F. Distelmaier: These authors contributed equally to this work.     

Die Beeinflussung der Fibrinogengerinnung durch Ribosenukleinsäure und adenosintriphosphorsaures Na (ATP)

Summary The coagulation of fibrinogen by thrombin is delayed by yeast nucleic acid and still more by adenosin-3-phosphoric acid. This action is due to a free phosphoric acid group and can be measured already in concentrations of 6 mg% yeast nucleic acid or of 2 mg% adenosin-3-phosphoric acid, whereas ATP only becomes effective in a concentration of 75 mg %.     

An enzymatic spectrophotometric assay for inosinic acid

Summary An enzymatic, spectrophotometric assay for inosinic acid is described. Inosinic acid is reacted with excess pyrophosphate in the presence of magnesium ions and hypoxanthine guanine phosphoribosyltransferase to form hypoxanthine which is oxidized to uric acid in the presence of xanthine oxidase. Inosinic acid concentration is measured by the increase in absorption at 293 nm at the end of the reaction.     

Chemie und Stoffwechsel der Polyenfettsäuren

Summary The chemical structure of the polyenoic fatty acids occuring in organ phosphatides and in fish oils is reviewed. The double bonds of all these polyenoic acids are arranged in divinylmethane pattern. Except some of the C₁₆-polyenoic acids of fish oils, these polyenoic acids belong either to the oleic, linoleic or linolenic acid type and have chain lengths C₁₈, C₂₀, and C₂₂. Polyenoic acids of the oleic acid type are present only in small amounts in phosphatides of mammalian origin. Fish oils are lacking in these but predominantly contain polyenoic acids of the linolenic acid type.Metabolic studies have shown that polyenoic acids of linoleic acid type (e.g. arachidonic acid) originate from linoleic acid and those of the linolenic acid type (e.g. C₂₀-pentaenoic and C₂₂-hexaenoic acid) from linolenic acid-both supplemented exogenous-by extension of the carbon chain by acetate on the side of the carboxylic acid group and introduction of additional double bonds in the divinylmethane pattern directed toward the carboxylic acid group. There is some evidence, however, that a total synthesis of the polyenoic acids of the oleic acid type occurs in the animal body.The transformation of linolenic to C₂₂-hexaenoic acid and some intermediate reactans have been investigated more precisely by means of the tracer method. As far as the biosynthesis of the polyenoic fatty acids is concerned there are no fundamental differences in different vertebrates.

---

---

Nach einem Vortrag auf der gemeinsamen Tagung der deutschen, französischen und schweizerischen Biochemiker in Zürich vom 10.–12. Oktober 1960.     

A peculiar fatty acid, (Z,Z)-9,12,17-octadecatrienoic acid,identified in the phospholipids of the pea aphid,Acyrthosiphon pisum (Harris) (homoptera: aphididae)

A peculiar fatty acid previously detected in the phospholipids of the pea aphid,Acyrthosiphon pisum, is identified as (Z,Z)-9,12,17-octadecatrienoic acid. It is the first report of this compound in the literature. Comparison of fatty acid profiles of phospholipids between normal and aposymbiotic pea aphids shows that aphid symbionts are not responsible for the biosynthesis of this unusual fatty acid.     

Degradation of encephalitogenic protein in aerobic ascorbic acid solutions.

Aerobic ascorbic acid solutions are capable of extensively cleaving the peptide chain of the myelin basic protein. Cleavage occurred most readily with C-terminal to aspartic acid, serine, threonine, glutamic acid and leucine residues.     

金银藤挥发油成分的气-质联用分析与化学计量学解析

目的 定性、定量分析金银藤挥发油成分.方法 采用气相色谱-质谱进行检测,通过化学计量学解析法对二雏色谱/质谱数据进行解析,得到各组分的纯色谱曲线和质谱,从而实现对金银藤挥发油成分的定性、定量分析,并结合程序升温保留指数来鉴定化合物.结果 金银藤的挥发油鉴定了39个成分,定性组分含量占金银藤挥发油成分总含量的94.54%.结论 全银藤挥发油的主要成分为十六烷酸（45.86%）、9,12-十八碳二烯政乙酯（39.02%）、十四烷酸（1.8%）、十五烷酸（1.07%）、十八烷酸（1.02%）.     

Metabolic pathways of delta-aminolaevulinic acid in Rhodopseudomonas spheroides.

Incorporation of delta-aminolaevulinic acid 5 14C and 4 14C into the inosine monophosphate pool and into porphyrins, was studied in cell suspensions of R. spheroides. The results contradict a direct incorporation of delta-aminolaevulinic acid into the purine ring of nucleotides through gammadelta-dioxovaleric acid. It would suggest a nonspecific incorporation after degradation of delta-aminolaevulinic acid without a transamination as a first reaction.     

Über den Intermediär-Stoffwechsel vonAspergillus niger

Summary Oxalic acid is only dissimilated if other carbon sources are present (e.g. citric acid, succinic acid), whereas malonic acid is also dissimilated as a single component byA. niger. It is supposed that the latter is used by the mould not only energetically but also for building up cell substance.     

Central effect of 5,8,11,14-eicosatetraenoic acid (arachidonic acid) on the temperature in the conscious rabbit

Hyperthermia induced by arachidonic acid in rabbit was attenuated by phenoxybenzamine, cyproheptadine and indomethacin. The reduction in arachidonic acid hyperthermia, after 6-OH-DA and the failure of PCPA to reduce this rise, indicates the involvement of noradrenaline in arachidonic acid hyperthermia.     

Effects of alloxan on orotic acid and glycogen content in various vertebrate species.

Alloxan treatment induces a decrease of orotic acid content in various organs of carp, frog, pigeon and rat, parallel to a decrease of liver and muscle glycogen content. Loss of orotic acid and glycogen cannot be prevented by orotic acid and carbamyl phosphate given i.p. Mice, rats and pigeons use up and excrete exogenous orotic acid rapidly, but carps and frogs accumulate it.     

Effects of alloxan on orotic acid and glycogen content in various vertebrate species

Summary Alloxan treatment induces a decrease of orotic acid content in various organs of carp, frog, pigeon and rat, parallel to a decrease of liver and muscle glycogen content. Loss of orotic acid and glycogen cannot be prevented by orotic acid and carbamyl phosphate given i.p. Mice, rats and pigeons use up and excrete exogenous orotic acid rapidly, but carps and frogs accumulate it.