胡萝卜与烟草原生质体的低温保存

在较长的时间内,可保持正常生理状态与细胞活性的原生质体的制备及保存技术是进行空间细胞融合实验的前提条件。本研究以0.7ml/L的葡萄糖作渗透压,在6-8℃低温条件下经过72小时保存后,供试原生质体的存活率仍可达81%,并保持了其长壁与分裂的特性。 Abstract:Storage duration and acativity of isolated protoplasts are important problem for experiment on plant cell fusion in space.We have achieved preliminary success using glucose as osmotic reagent,The survival protopasts after 72 hour storage in 0.7mol/L glucose at 6~8℃ reached 81% and maintained a very high activity of division.     

Insulin and insulin mutants stimulate glucose uptake in rat adipocytes

A simple method to determine the in vitro biological activity of insulin by measuring glucose uptake in the rat adipocytes is presented here. In the presence of insulin, the glucose uptake is 5-6 times more than the basal control. And the uptake of D-[3-3H]-glucose is linear as the logarithm of insulin concentration from 0.2 μg/L to 1.0 μg/L. Glucose and 3-O-methyl-glucose inhibit D-[3-3H]-glucose uptake into adipocytes. By this method, the in vitro biological activity of [B2-Lys]-insulin and [B3-Lys]-insulin was measured to be 61.6% and 154% respectively, relative to that of insulin.     

Insulin sensitivity and inhibition by forskolin, dipyridamole and pentobarbital of glucose transport in three L6 muscle cell lines

L6 skeletal muscle myoblasts stably overexpressing glucose transporter GLUT1 or GLUT4 with exofa- cial myc-epitope tags were characterized for their response to insulin. In clonally selected cultures, 2-deoxyglucose uptake into L6-GLUT1myc myoblasts and myotubes was linear within the time of study. In L6-GLUT1myc and L6-GLUT4myc myoblasts, 100 nmol/L insulin treatment increased the GLUT1 content of the plasma membrane by 1.58±0.01 fold and the GLUT4 content 1.96±0.11 fold, as well as the 2-deoxyglucose uptake 1.53±0.09 and 1.86±0.17 fold respectively, all by a wortmannin-inhibitable manner. The phosphorylation of Akt in these two cell lines was increased by insulin. L6-GLUT1myc myoblasts showed a dose-dependent stimulation of glucose uptake by insulin, with unaltered sensitiv- ity and maximal responsiveness compared with wild type cells. By contrast, the improved insulin re- sponsiveness and sensitivity of glucose uptake were observed in L6-GLUT4myc myoblasts. Earlier studies indicated that forskolin might affect insulin-stimulated GLUT4 translocation. A 65% decrease of insulin-stimulated 2-deoxyglucose uptake in GLUT4myc cells was not due to an effect on GLUT4 mobi- lization to the plasma membrane, but instead on direct inhibition of GLUT4. Forskolin and dipyridamole are more potent inhibitors of GLUT4 than GLUT1. Alternatively, pentobarbital inhibits GLUT1 more than GLUT4. The use of these inhibitors confirmed that the overexpressed GLUT1 or GLUT4 are the major functional glucose transporters in unstimulated and insulin-stimulated L6 myoblasts. Therefore, L6-GLUT1myc and L6-GLUT4myc cells provide a platform to screen compounds that may have differ- ential effects on GLUT isoform activity or may influence GLUT isoform mobilization to the cell surface of muscle cells.     

沙打旺原生质体培养再生植株

用1%半纤维素酶,0.4%纤维素酶,0.1%果胶离析酶,CPW9M酶液分离沙打旺无菌苗下胚轴和子叶原生质体。K8P原生质体培养基悬滴培养。下胚轴原生质体形成小细胞团后用琼脂糖包埋培养,形成小块愈伤组织后转入增殖培养基M1、M2(改良MS培养基)上形成大块愈伤组织。经过两次诱导分化,在分化培养基M3(MS 0.7mg/L BA 0.2mg/L NAA),M4(MS 0.5mg/L BA 0.5mg/L KT 0.5mg/L ZT 0.2mg/L NAA)和M6(MS 3mg/L ZT 0.2mg/L IAA)上分化出苗,再生植株。由子叶分离的原生质体未能形成愈伤组织。     

Inhibition of metastasis to lung of a human nasopharyngeal carcinoma cell line CNE-2L2 transfected with pRc/CMV-antisense 6A8 cDNA in nude mice

The growth of CNE-2L2 cell, a cloned line of human nasopharyngeal carcinoma with a high potentiality of metastasis to lung was inhibited to a certain extent after transfection with a recombinant antisense expression vector of a cDNA encoding a human α-mannosidase (pRc/CMV-antisense 6A8 cDNA)( the Genbank accession number of 6A8 cDNA is U37248) in comparison with that of the cell transfected with the Mock and of the wild cell. Two months after a subcutaneous inoculation of CNE-2L2 cell into the axilla of nude mice metastatic lesions in the lung were observed in 9/10 mice (90%) with grade Ⅲ in 8 mice and grade Ⅱ in one mouse in the wild cell group, in 6/8 mice (75%) with grade Ⅲ in one mouse, grade Ⅱ in 2 mice and grade Ⅰ in 3 mice in the Mock-transfection group, in only 3/10 mice (30%) with all grade Ⅰ in pRc/CMV-antisense 6A8 cDNA-transfection group.     

Submerged culture of chromium-enriched Termitomyces albuminosus

A species of mushroom, Termitomyces albuminosus, was cultured in liquid medium for production of chromium-enriched mycelium. The influence of chromium （Ⅲ） on mycelial growth of T. albuminosus was investigated. An optimum medium composed of 5.6g/L yeast extract, 51.6g/L hydrolyzed rice, 2g/L KH2PO4, and 20mg/L chromium（Ⅲ） with initial pH of 4.5 was obtained by using method of central composite design （CCD）. After incubation of 84h, the maximal biomass of chromium-enriched mycelia reached 24.23g DMW（dried mycelial weight）/L with 272μg/g DMW chromium content in 500mL flasks containing 100mL medium with an inoculum of 8% on a shaker of 100r/min under an optimized cultivation condition at 28 ℃.     

Glucose regulates LXRα subcellular localization and function in rat pancreatic β-cells

Liver X receptors （LXRs） are members of the nuclear receptor superfamily, which have been implicated in lipid homeostasis and more recently in glucose metabolism. Here, we show that glucose does not change LXRα protein level, but affects its localization in pancreatic β-cells. LXRα is found in the nucleus at 8 mM glucose and in the cytoplasm at 4.2 mM. Addition of glucose translocates LXRα from the cytoplasm into the nucleus. Moreover, after the activation of LXR by its synthetic non-steroidal agonist （T0901317）, insulin secretion and glucose uptake are increased at 8 mM and decreased at 4.2 mM glucose in a dose-dependent manner. Furthermore, at low glucose condition, okadaic acid reversed LXRα effect on insulin secretion, suggesting the involvement of glucose signaling through a phosphorylation-dependent mechanism.     

Chromium-induced glucose uptake, superoxide anion production, and phagocytosis in cultured pulmonary alveolar macrophages of weanling pigs

The dose-dependent effects of chromium chloride (CrCl₃) and chromium picolinate (CrPic) were evaluated for their glucose uptake, superoxide anion (O ₂ ⁻ ) production, activity of glucose-6-phosphate dehydrogenase, and phagocytosis of incubated pulmonary alveolar macrophages in medium containing no or 5 × 10⁻⁸ M insulin. Glucose uptake was found to increase in cells treated with 20 μg/L CrCl₃. Incubation with 20 μg/L of CrPic enhanced glucose uptake and O ₂ ⁻ production in an insulin-dependent manner. However, the inclusion of CrPic to 100 μg/L in the medium absent of insulin also increased O ₂ ⁻ production. The activity of glucose-6-phosphate dehydrogenase was not affected by either the addition of Cr or insulin. The phagocytosis of Escherichia coli by macrophages was enhanced significantly (p<0.05) in medium containing 10–100 μg/L CrCl₃ or 20–100 μg/L CrPic in the presence of insulin. These results suggest that the addition of 10–20 μg/L CrCl₃ enhances directly the cellular activity of macrophages, whereas the effect of CrPic requires the cooperative action of insulin in enhancing their glucose uptake and phagocytosis.     

Influence of carbon source on growth,biochemical composition and pigmentation of Ankistrodesmus convolutus

The unicellular chlorophyte Ankistrodesmus convolutus Corda was grown in the light using inorganic medium (Bold's Basal Medium, BBM) and BBM enriched with 0.1% w/v of glucose, sodium acetate, sodium citrate or sodium bicarbonate. Glucose supported the highest specific growth rate (μ = 0.93 d^-1) and gave the highest biomass (453 mg dry weight L^-1) at the time of harvest. Of four glucose concentrations (0.05, 0.1, 0.25, 0.5% w/v), best growth was attained at 0.1% w/v. At 0.5% w/v glucose, the cells had high carbohydrates but low lipids and proteins. The relative amounts of 16:0, 18:0, 18:1 and 18:2 increased at the expense of 18:3(n-3) in the carbon-supplemented cultures and at glucose concentrations higher than 0.1% w/v. Cultures grown on glucose had less chlorophyll and carotenoid contents than cultures grown on other carbon sources. Chlorophyll and carotenoid contents decreased with increasing glucose concentrations in the medium.     

Factors Influencing Formation of Sclerotia in Grifola umbellate （Pers.） Pilaet Under Artificial Conditions

The effects of substrate composition and temperature on myceilal growth and sclerotium production in Grlfola umbellate （Pers.） Pilaet were Investigated In the present study. The Induction of sclerotla of G. umbellate was affected greatly by the type of medium, as well as the type of carbon source. Malt-extract agar was able to induce the production of sclerotia. The production of sclerotia was also observed when the carbon source in the GPC agar medium （glucose 20 g/L, peptone 6 g/L, corn steep liquor 10 g/L, and agar 15 g/L） was replaced with glycerol or mannitol. Altering the composition of the GPC medium with milk powder, thiamine hydrochlorlde, extract of Armlllarla mellea, active clay, dlatomite, kaolin, or arginlne did not induce the production of sclerotla. A temperature range of 18-25 ℃ was suitable for both mycellai growth and sclerotium formation. Glycerol significantly Induced slerotium formation on nutrient supplemented with sawdust substrates In bottle culture. 24S-Polyporusterone A and polyporusterone B were assayed In samples of natural and cultured sclerotla. Both natural and cultured sclerotla contained 24S- polyporusterone A and polyporusterone B.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.