适宜浓度短链脂肪酸混合物对小胶质细胞炎症 抑制及机制研究

本研究的主要目的是探讨适宜浓度短链脂肪酸(short chain fatty acids,SCFAs)混合物对炎症环境下小胶质细胞的抑炎作用及其机制.采用脂多糖(LPS)刺激小鼠小胶质细胞系BV-2细胞建立神经炎症模型,并利用CCK8试剂盒检测不同浓度单一的乙酸钠、丙酸钠、丁酸钠处理后的细胞活力.设计选取这三种SCFAs对细胞活力无影响、且有抑炎效果的特定浓度进行组合(SCFAs mix),进一步检测SCFAs mix对LPS刺激下BV-2细胞炎症反应的影响及机制,包括:a.用一氧化氮(NO)试剂盒检测NO的释放;b.用ELISA检测炎症因子TNF-α、IL-6的释放;c.用qRT-PCR和Western blot检测炎症因子TNF-α、IL-6、炎症小体NLRP3、炎症通路相关蛋白TLR4、NF-κB等的表达变化.结果表明LPS刺激BV-2细胞4 h后,在体系中添加特定浓度的单一SCFA处理12 h后,不能缓解BV-2细胞的炎症反应,而将上述SCFAs配制成同等终浓度的SCFAs mix处理12 h却能显著降低细胞培养上清液中NO、TNF-α和IL-6 (均P0.001)的量,还能抑制BV-2细胞内iNOS、TNF-α、IL-6和NLRP3 mRNA的升高(均P0.001);通过对炎症信号通路关键分子的检测发现,SCFAs mix可以抑制LPS诱导的BV-2细胞内TLR4、MyD88、TRAF6和NF-κB蛋白的表达升高.综上可见:适宜浓度的混合SCFAs可通过调控TLR4/MyD88/TRAF6/NF-κB炎症通路抑制LPS诱导的小胶质细胞的炎症反应,而起到抗炎的保护作用.     

The Effect of Temperature and Parental Age on Recombination and Nondisjunction in CAENORHABDITIS ELEGANS

The effect of temperature and parental age on recombination frequency in C. elegans was studied between pairs of closely linked markers on linkage groups I and V. In the regions studied, recombination frequency varied three-fold over the temperature range 13.5° to 26°. Temperature-shift experiments indicated that a temperature-sensitive recombination event occurs approximately 50 oocytes prior to fertilization. Recombination frequency was observed to decrease with maternal age. The greatest decrease was observed in the first 24 hours of egg production. The frequency of male progeny, a measure of X-chromosome nondisjunction was also studied. This frequency increased with elevated temperature and age of the parent.     

The Effects of Chilling Temperature on Photosystem II of Cucumber

Chilling (1 ℃ or 5℃, 16 h) treatment inhibited PSⅡ but not PSⅠ of photosynthesis in cucumber, a chilling sensitive plant. Oxygen evolution, variable fluorescence, and DCIP photoreduction were inhibited significantly, and the latter two could be recovered to the control level by adding artificial electron donors. These results suggest that chilling temperature damages PSⅡ of cucumber only on the oxidizing side and does not affect its reaction center.     

低温对植物叶片中超氧物歧化酶、过氧化氢酶和过氧化氢水平的影响

番茄和鸡蛋果叶片中可提取的SOD活性不受低温的影响。在电泳谱带上SOD主同工酶带被氰化物而不被低温抑制,次同工酶带在低温下不稳定,且活性很低,它的变化不影响总的SOD活性。一些冷敏感植物叶片中CAT活性被低温抑制,而H_2O_3水平在低温下稳定或有增加,这可能使毒性更强的羟基离子(OH·)易于形成。     

烫伤大鼠早期口服谷氨酰胺对血浆氨基酸代谢的影响

研究烫伤早期口服谷氨酰胺 (GLN)后GLN及其相关氨基酸的代谢变化。以Wistar大鼠为烫伤模型 ,烫伤后早期口服GLN ,并以 83 5-50型氨基酸自动分析仪的生理体液法测定血浆游离氨基酸。结果烫伤后饲标准饲料(C)组血浆GLN在烫伤后 2d和 5d降低 ,与GLN代谢相关的丙氨酸和氨无显著性变化 ;GLN饲料 (G)组各时相点GLN均增加 ,1 0h和 8d增加显著 ,与GLN代谢相关的丙氨酸和血氨增加显著 ;GLN +精氨酸 (G +A)组GLN在 2d降低 ,血氨升高显著。与C组比 ,G和G +A组血浆总氨基酸、支琏氨基酸、GLN、丙氨酸、r-氨基丁酸和氨均较C组高。提示 ,烫伤后早期口服GLN能提高血GLN和与之代谢相关的氨基酸浓度。     

Effect of Age on Adenosine Triphosphatase Activity from Tobacco Chloroplasts

Adenosine triphosphatase activity of tobacco leaf chloroplasts in the dark was measured, using leaves of different age as determined by the position of the leaves along the stem. The activity of the chloroplast preparations strongly decreased with age, regardless of the addition of Mg²⁺ or Ca²⁺. Opposite effects of Mg²⁺ and Ca²⁺ on the activity of the chloroplasts were noted in experiments where different ratios of Mg²⁺/Ca²⁺ were applied. They were related to the age of the leaves, Ca²⁺ strongly stimulated the activity of the preparations from old leaves but was practically without effect in young, just expanded leaves. Mg²⁺ slightly stimulated the activity from old leaves while it invariably inhibited the hydrolytic activity of preparations from young leaves.     

The Relation between Concentration of Hydrogen Ions and the Effect of Weak Acids or Bases on Metabolic Activity

The relation between the concentration of hydrogen ions andthe effect of a weak acid on metabolic activity as indicativeof the role of ions and molecules is considered. Special referenceis made to a metabolic system containing nonmobile anions. Theconsequence of substituting divalent cations for univalent isindicated.     

利用液相色谱研究烘焙条件对白肋烟中游离氨基酸的影响

利用OPA、FMOC联合在线衍生反相高效液相色谱法测定白肋烟在110℃、120℃、130℃、140℃、150℃分别烘焙12m in和16 m in后游离氨基酸的含量,研究烘焙温度和烘焙时间对白肋烟中游离氨基酸的影响。结果显示整个烘焙过程是蛋白质的降解和M ailard反应相结合的动态过程,蛋白质的降解主要发生在110℃~120℃的低温区;而M ailard反应主要发生在130℃~150℃高温区。实验结果还表明烘焙时间对白肋烟在烘焙后游离氨基酸的含量有重要影响,烘焙时间的延长使烟叶中的游离氨基酸均有较大幅度降低,其中影响最明显的是Pro、Asp和Asn。     

Chilling Cells Enhances the Bactericidal Action of Fatty Acids on Escherichia coli

[This corrects the article on p. 153 in vol. 31.].     

Influence of Root and Content on the Temperature Response of Net and Uptake in Chilling Sensitive and Chilling Resistant Lycopersicon Taxa

We studied the influence of internal ammonium and nitrate contenton the temperature response of ammonium and nitrate uptake inboth chilling sensitive and chilling resistant tomatoes. Threetaxa were examined: Lycopersicon esculentum Mill. cv. T-5, achilling sensitive cultivar, Lycopersicon hirsutum Humb. andBompl. LA 1264, a wild, chilling sensitive accession from thelowlands of Ecuador, and Lycopersicon hirsutum LA1778, a chillingresistant accession from the highlands of Peru. Short exposures(4 h) of L. esculentum cv. T-5 to chilling temperatures irreversiblyinhibited ammonium absorption for at least 6 h. Nitrate absorptionin this taxon and ammonium and nitrate absorption in the L.hirsutum accessions recovered fully and immediately from suchexposures. The chilling resistant accession, L. hirsutum LA1778,showed a lower Q₁₀ for ammonium absorption (1?54?0?10, mean?s.e.)than its chilling sensitive relatives, L. hirsutum LA1264 (2?37?0?35)and L. esculentum cv. T-5 (1?92?0?11). The temperature responseof nitrate absorption depended on internal nitrate status; plantsgrown at high levels of ammonium and nitrate (200 mmol m^–3)showed higher Q₁₀'s for nitrate uptake (2?29?0?10) than thosedepleted of internal (1?86?0?12). Key words: Lycopersicon, ammonium, nitrate, temperature response, chilling     

The Effect of Temperature on the Level and Biosynthesis of Unsaturated Fatty Acids in Diacylglycerols of Brassica napus Leaves

Experiments on the effects of temperature on the levels of unsaturated fatty acids and their rates of desaturation in Brassica napus leaf lipids have shown that significant differences occur in the composition of all diacylglycerols in the leaf between plants grown at high and low temperatures. In the major thylakoid diacylglycerols, monogalactosyl-diacylglycerol and digalactosyldiacylglycerol, not only is there an increase in the level of unsaturation at low temperatures, but there is a change in the balance between molecular species of chloroplastic origin (16/18C) and cytosolic origin (18/18C). Radioactivity tracer data indicate that at low temperatures there are two distinct phases of desaturation in the fatty acids of the major diacylglycerols of these leaves. A rapid phase, which appears in plants grown at low temperatures and results in the desaturation of palmitic acid to hexadecadienoic acid and oleic acid to linoleic acid may explain the high levels of unsaturated fatty acids found in the leaf diacylglycerols from plants grown at low temperatures. The appearance of this rapid phase is controlled by the temperature at which the plant is grown and is not subject to rapid variations in environmental temperature.     

The Effect of Some Precursor Amino Acids and Enzyme Inhibitors on the Mouse Striatal Concentration of Tyramines and Homovanillic Acid

Abstract: The parenteral administration of L-phenylalanine or p -tyrosine increases the mouse striatal concentration of p -tyramine, an effect that is enhanced by monoamine oxidase inhibition and reduced by an L-aromatic aminoacid decarboxylase inhibitor. Striatal m -tyramine was increased following administration of L-phenylalanine or m -tyrosine and enhanced further by monoamine oxidase inhibition. It was also observed that m -tyrosine is a better substrate for decarboxylation than p -tyrosine, and that p -tyrosine decarboxylation was blocked by NSD 1055, while that of m -tyrosine was enhanced. The results obtained indicate that both isomers of tyramine are formed in the mouse striatum by hydroxylation of L-phenylalanine to p - or m -tyrosine followed by decarboxylation by a specific decarboxylase; an alternative pathway could be first the decarboxylation of phenylalanine to β-phenylethylamine, followed by its hydroxylation to p - or m -tyramine.     

Scopolin, a Biochemical Marker for Resistance to Thielaviopsis basicola in Callus and Crown-Gall Tissue Cultures of Tobacco

Scopolin concentration increased in tissue cultures where Thielaviopsis basicola growth ceased (primary and established callus cultures of the resistant tobacco cultivar Ky 170) while it decreased in tissue cultures where fungal growth persisted (primary and established callus cultures of the susceptible tobacco cultivar Ky 151 and crown-gall cultures of Ky 170 and Ky 151). The concentration of chlorogenic acid, scopoletin, and two other unknown soluble phenols varied after inoculation and no, correlation with tissue culture resistance could be established. Incorporation of Agrobacterium tumefaciens T-DNA in the genome of both cultivars induced a drastic reduction of scopolin in inoculated tissue cultures. T-DNA incorporation had less, influence on uninoculated tissues. Scopolin at concentrations found in tissue cultures was not toxic to the fungus.     

生长温度对烟草叶片环式电子传递活性的影响

高等植物的光合机构在环境胁迫条件下非常容易产生光抑制,环式电子传递在光合机构的光保护中发挥着重要的作用.但是,生长温度对环式电子传递的影响并不清楚.本研究测定了在24/18℃和32/26℃条件下生长40天的烟草(K326)叶片的气体交换、叶绿素荧光和P700氧化还原态的光响应曲线.结果表明,烟草叶片在两种生长温度下的的光合能力、光化学淬灭、非光化学淬灭和通过光系统Ⅱ的电子传递速率(ETR Ⅱ)均没有差异.但是,在强光条件下,生长在24/18℃的叶片比生长在32/26℃的具有更高的通过光系统Ⅰ的电子传递速率(ETRⅠ)和ETRⅠ/ETR Ⅱ比值.短时间的强光处理后,生长在24/18℃的叶片具有较高的光系统Ⅱ最大量子产额(Fv/Fm),表明环式电子传递活性的上调有助于缓解生长在24/18℃的叶片光系统Ⅱ受到的光损伤.综上所述,环式电子传递活性的增强是植物适应较低生长温度的重要策略.     

实验动物血及组织游离氨基酸含量

本文报告实验动物血及组织游离氨基酸含量,结果表明,实验狗和Wistar大鼠血游离氨基酸含量比较恒定。实验兔组织游离氨基酸含量普遍高于血。     

Studies on the Eeo-Physiological Indices of Rubber Trees at Chilling Temperature

Rubber trees (Hevea brasilieasis Muell-Arg.) like other tropical trees, are very sensitive to chilling temperature. It may cause metabolic disturb ances and make severe injuries to the tree. The ecophysiological indices introduced in this paper are transpiration rate, osmotic pressure, pretoplasmic viscosity, protoplasmic permeability and water content. These indices can be used to estimate relative cold resistance of different clones or individual rubber seedlings. The results our measurements are summarized in the following table.     

低温与光对黄瓜幼苗子叶光合电子传递活性的影响

25～30℃和30 μmol m~(-2)s~(-1)光下培养的黄瓜幼苗,在黑暗下经 1～7℃处理24h或5℃处理24～72h,光合电子传递活性受不同程度的抑制;其抑制部位主要在PSⅡ氧化侧;随温度的降低和时间的延长,抑制部位可发展至PSⅡ及之后的电子递体上,但尚未影响PSⅠ的活性。160μmol m~(-2)s~(-1)的光强加重低温对电子传递活性的抑制,光强越高,则加重的程度越高;抑制部位从PSⅡ氧化侧发展至PSⅡ反应中心以及PSⅠ。     

The Effect of Prolonged Chilling on Water Movement and Radial Growth in Trees

1. The woody shoots of young saplings of Fraxinus.excelsior andAcer Pseudo-platanus in pots were subjected to continuous coolingto about 2° C. during the growth season, with the resultthat radial growth was almost completely inhibited throughoutthe woody stem.
2. The chilling did not adversely affect extensiongrowth exceptthat it was later in commencement and proceededmore slowly.
3. If the temperature around the stem is loweredfrom 2° C.to 0° C., water conduction is cut down tosuch an extentas to cause wilting of the leafy shoots; turgidityis recoveredwhen the temperature is again raised to 2°C.
4. This wilting effect is discussed particularly in relationtothe part played by living cells in the upward movement ofwaterin the wood.

     

Effects of Cytokinins on the Nucleic Acids of Tobacco Pith

Cylinders of pith of Nicotiana tabacum var. Wis. 38 were asepticallyisolated and grown on a mineral-sucrose medium in the presenceand absence of either kinetin or zeatin. On medium containing kinetin (5x10⁶M) the increase in the residualdry weight of cylinders was greater than that on control mediumafter 2 d culture and this was maintained at 5 d. At 2, 5, and7 d there were increments in the DNA and RNA levels of cylindersdue to kinetin treatment and these increased progressively. A double-labelling method coupled with acrylamide gel electrophoresiswas used to study the effects of kinetin at 5 x 10^–6Mand zeatin at 10^–6 M on the incorporation of radioactiveprecursors into the RNA of cylinders given a 4-h label pulse.No effects of zeatin were observed after 1 d nor of kinetinat 2 d but after 4 d zeatin stimulated incorporation into ribosomal,transfer and poly-disperse RNA and kinetin did likewise after5 d. Incorporation measured at 7 d was reduced in cylindersfrom which kinetin had been removed at 5 d compared to thoseto which it had been supplied continuously. Scans at 260 run of the electrophoretic fractionations of RNAafter 2, 5, 7, and 9 d of culture showed that both in the absenceand in the presence of kinetin the proportion of 4S RNA increasedfrom about 20 per cent to over 50 per cent of the total between2 and 5 d of culture and after 5 d the ribosomal RNA gave aberrantscans apparently indicative of degradation. These aberrant scanspersisted in RNA extracted after 27 d culture in both the presenceand absence of kinetin.