Effect of Copper on Growth of Yeast

The effect of copper was tested on the growth of many strains of yeast. Plate culture on density gradient agar of copper was used for estimating the growth response to copper. Growth in many strains was more strongly inhibited by the copper-aquo complex than by the copper-amino acid complex. Debaryomyces hansenii IFO 023 was found a suitable strain for the present study, because it was not resistant, not producing H₂S, and copper absorption by this strain was similar to that of the resistant strain. Growth of yeast cells in medium containing copper was affected by pH and concentration of amino acid in medium. Absorption of copper into intact cells was almost saturated for the initial few minutes. It was also affected by the addition of amino acid to copper solution. Our results indicated that the growth response of yeast to copper was closely related to copper absorption into cells. About 60 percent of copper absorbed into cells was distributed in the soluble fraction of the cell homogenate which was obtained by centrifugation at 105,000 g for 60 min.     

猕猴桃实生苗再生体系的建立

以成熟饱满的美味猕猴桃种子发芽获得实生苗,分别以实生苗的茎段、叶柄和叶片为材料建立了再生体系。结果表明:种子以2.5mg/L的赤霉素(GA3)处理8h较适合;以培养基发芽较为适合;茎段、叶柄和叶片的愈伤组织的诱导率均为100%,且茎段、叶柄比叶片容易脱分化,但叶片的平均出苗率最高。再生苗在移栽5d后,开始长出新叶,10d后就能完全适应外界环境。     

The origin of transfer of P307

The DNA fragment carrying the oriT region from the enterotoxin plasmid P307 was isolated and its polynucleotide sequence was determined. Using Southern hybridization assays with a synthetic oligonucleotide probe, the oriT region was identified on a 7.9-kb EcoRI fragment from P307. By ligating the fragment with the cloning vector pUC119, plasmid pAG10 was obtained. The physical map of the insert was determined and oriT was located on a 540-bp BglII/SalI fragment. After this fragment was subcloned into sequencing phages, the polynucleotide sequence was established. Part of the sequence proved to be almost identical to segments of the oriT regions of the plasmids F and R1; another neighboring region was very different among all three sequences. The polynucleotide sequence proximal to traM is highly similar to that of F but different from that of R1.     

112株志贺菌菌群分布和药敏特点分析

目的研究本地区2001年至2005年志贺菌菌群分布及其药敏特点,以指导临床合理抗菌治疗。方法经大便培养筛选志贺菌,用生化和血清学方法鉴定菌群和血清型,采用K-B法检测病原菌耐药性。结果在112例细菌性痢疾患者中,男女比例相似,年龄分布以婴幼儿最高,临床表现不典型者较多,菌群分布以福氏志贺菌最多,F2b为优势血清型,对抗菌药物敏感性差异有显著性。结论近5年来本地区细菌性痢疾患者发病特点有年龄差异,菌群仍以福氏志贺菌为主,血清型以F2b为主,第3代头孢菌素是治疗细菌性痢疾最佳的抗菌药物。     

Secretion and degradation of parathormone as a function of intracellular maturation of hormone pools

The biosynthesis, processing, and secretion of parthormone and the effect of calcium on these processes were measured in dispersed porcine parthyroid cells incubated with [(35)S]methionine. Proparathormone was detected at 10 min, the earliest time measured, and was rapidly and apparently quantitatively converted to parathormone. The half-life of the prohomormone pool was 15 min. Secretion of parathormone was detected by 20 min. In pulse-chase experiments there was a period between 20 and 40 min during which the wave of newly-synthesized parathormone was secreted. After 40 min during little additional radioactive hormone was secreted, but dibutyryl cyclic AMP, an agent that can mobilize stored parathormone, when added to the incubation mixtures enhanced radioactive parathormone secretion but only after 60 min, although it increased net hormone secretion as determined by radioimmunoassay to the same extent at all times studied. When the ionized calcium concentration of the medium was lowered, more radioactive hormone was secreted at all times but the effect was greatest on that hormone that was synthesized less than 60 min previously ; however, net hormone secretion in contrast to radioactive hormone was enhanced equally at all intervals. These data could mean that the refractoriness to secretion of parathormone 40-60 min of age was related to maturation of secretory container preparatory to storage. Low calcium (0.5 mM) stimulated hormone secretion up to fivefold compared to high calcium (3.0 mM) but did not affect synthesis of parathormone or proparathormne or conversion of the latter to hormone. During processing at least 70 percent of the intracellular parathormone was lost, presumably through proteolysis and this degradation was greater at high calcium. These data have been interpreted in light of the concept that two secretable pools of parathormone exist within the parathyroid.     

Growth of a turbidostatic culture of yeast under conditions of thermal stress at various pH's of the media

A turbidostat Saccharomyces cerevisiae 14 culture was grown at pH 6.0 to 2.25 and subjected to a heat pulse (the optimal temperature of 30 degrees C was elevated to 37.5 degrees C) in order to study its response. The growth rate was determined in the first cell generation after the pulse. The culture grown at pH 6-4 was shown to be thermotolerant whereas the yeast was thermosensitive at pH 2.4-2.25. The cells became thermotolerant at 37.5 degrees C after the transitions: pH 2.25----4 and pH 2.35----4. The yeast thermoresistance was shown to depend on H+ concentration. Apparently, the yeast thermotolerance was determined by the effective functioning of the chemo-osmotic system.     

重组人尿激酶原的临床研究概况

尿激酶原或尿激酶型纤溶酶原激活剂具有特异性溶解血栓作用,引起人们的极大兴趣。西方国家1986年开始进行临床研究,A-74187或Sp2/0表达的糖基化尿激酶原以及大肠杆菌表达的非糖基化尿激酶原治疗急性心肌梗死阻塞相关血管开通率为70%~80%。德国Grünenthal公司用大肠杆菌表达的非糖基化尿激酶原(Saruplase)治疗急性心肌梗死研究采用20 mg推注,60 mg/60 min滴注,分别与重组组织型纤溶酶原激活剂、尿激酶、链激酶进行比较,并做了1698名心肌梗死患者的开放性临床试验,梗塞相关血管的开通率达到70%~80%。Saruplase与链激酶在104个临床研究中心,入组3089名急性心肌梗死患者进行大规模临床试验。结果表明,Saruplase对阻塞相关血管开通率、30天死亡率、出血合并症等副作用与链激酶没有明显差异,而出血性中风发生率高于链激酶,欧盟未批准Saru plase上市。国产重组人尿激酶原也进行了探索研究,用于治疗急性心肌梗死给药剂量为30~60 mg,给药时间为30或60 min,阻塞相关血管开通率为63.4%~80.0%,而尿激酶为52.2%~66.7%(平均58.0%)。此外,国外用重组人尿激酶原治疗深层静脉血栓和缺血性中风进行了探索研究,但病例数较少,尚须进一步研究。     

Subunit Structure of Glucoamylase of Saccharomyces diastaticus

Extracellular glucoamylase produced by a starch-fermenting yeast, Saccharomyces diastaticus 5106-9A, was purified. The enzyme was found to be heterogeneous in molecular weight, ranging from approximately 80K to 66K as estimated by gel filtration, and consisted of two subunits, H and Y. The molecular weight of subunit H was heterogeneous and was determined to be approximately 68K, 59K, and 53K by acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The molecular weight of subunit Y was 14K, estimated by the same gel. the molecular weight of the deglycosylated form of subunit H was 41K, suggesting that the heterogeneity of the enzyme was due to glycosyl moieties of subunit H. Subunits H and Y were separated by gel filtration in the presence of sodium dodecyl sulfate. Subunit Y seemed to be hydrophobic, since it was insoluble in an aqueous buffer without detergent.     

Isolation and characterization of a cysteine protease of freesia corms

A protease, freesia protease (FP)-A, was purified to electrophoretic homogeneity from regular freesia (Freesia reflacta) corms in harvest time. The Mr of FP-A was estimated to be 24 k by SDS-PAGE. The optimum pH of the enzyme was 8.0 using a casein substrate. These enzymes were strongly inhibited by p-chloromercuribenzoic acid but not by phenylmethane-sulfonylfluoride and EDTA. These results indicate that FP-A belongs to the cysteine proteases. The amino terminal sequence of FP-A was similar to that of papain, and the sequences was regarded to the conservative residues of cysteine protease. From the hydrolysis of peptidyl-p-NAs, the specificity of FP-A was found to be broad. It was thought that FP-A was a new protease from freesia corms.     

Flower-inducing and -inhibiting activities of Phloem Exudate from Cotyledons of Pharbitis Seedlings

The flower-inducing and -inhibiting activities of phloem exudate (PE) prepared from cotyledons of Pharbitis seedlings were examined, using apex cultures in vitro from Pharbitis as a bioassay system.The PE was prepared from photoperiodically-induced cotyledons (SD-PE). The SD-PE was subjected to the following fractionations: When the SD-PE was extracted with CHCl₃ and then ethyl acetate, the inducing activity was located in the final aqueous fraction. The activity was localized in the diffusate when the aqueous fraction was dialyzed (molecular weight cut off was 10,000). The diffusate was fractionated by ion exchange chromatography, and flower-inducing activity was found in the fraction adsorbed onto anion exchange resin. When the fraction was applied to a Sep-Pak C18 cartridge, the activity eluted with 25% MeOH. As a result of the above fractionation, activity was increased about 30-fold.The nature of the flower-inhibiting activity of the PE taken from cotyledons exposed to continuous-light conditions was examined (CL-PE). The inhibiting activity was decreased as the cotyledons were exposed to longer dark periods; it appeared to be heat-stable. The CL-PE also inhibited flowering in Lemna. The CL-PE was subjected to the following fractionations: When the CL-PE was extracted with CHCl₃ and ethyl acetate, activity was located in the final aqueous fraction. Activity was localized in the diffusate when the aqueous fraction was dialyzed (molecular weight cut off was 10,000). When the diffusate was fractionated by ion exchange chromatography, the activity was found in the flow-through fraction. When the fraction was applied to a hydroxyapatite cartridge, the activity eluted with 25 mM sodium phosphate buffer. When the fraction was re-dialyzed (molecular weight cut off was 1,000), the diffusate contained the activity. As a result of the above fractionation, activity was increased about 10-fold.     

Effects of Extended Periods of Osmotic Stress on Water Relationships of Pepper

Pepper plants grown to uniform size in a controlled environment were subjected to an osmotic stress for periods of 1 to 10 days. Polyethylene glycol 400 was used as the osmotic agent. Leaf area of the plants, grown under uniform conditions, was proportional to the weight of the plants. This relationship was not altered by reduction in rate of growth due to a decrease in osmotic potential of the nutrient solution. The rate of transpiration of the pepper plants decreased as the osmotic potential of the nutrient solution was decreased. The reduction in rate of transpiration was most rapid when the osmotic potential was reduced from ?0.5 to ?7.5 bars. There was continued reduction in the rate of transpiration with change in potential to ?12.5 bar but this change was less than that at the higher potentials. The rate of transpiration remained at a reduced rate for as long as the plants were growing in the solution with low osmotic potential. Alternating the osmotic potential of the nutrient solution between ?0.5 and ?5.0 bar did not change the response to the ?5.0 tension. The reduction in rate of transpiration resulting from the lowering of the osmotic potential by addition of NaCl was similar to that produced by addition of polyethylene glycol. Water potential, osmotic potential, relative water content and stomatal movement were all in dynamic equilibrium with the water content of the leaves. The water content of the leaves was regulated by the supply and demand. In these investigations the demand remained constant. The supply was altered by decreasing the difference in water potential between leaf and substrate and by an increase in resistance to flow of water in the roots as a result of the decrease in osmotic potential of the nutrient solution.     

破色期番茄果实均一化cDNA沉默文库的构建和功能基因筛选模型的初步建立

番茄果实的成熟是由多基因精细调控的一个过程．利用破色期番茄果实,根据复性动力学原理在mRNA水平进行均一化操作使高丰度和低丰度的mRNA丰度接近．然后把均一化之后mRNA反转录得到cDNA,再与基因沉默载体pTRV重组,最后把构建好的载体通过电转化的方法转入到GV3101农杆菌中,从而建立起破色期番茄果实均一化cDNA沉默文库．通过番茄果实中病毒诱导基因沉默技术,对cDNA沉默文库进行初步筛选,从而确定功能基因筛选模型．在模型建立阶段,以番茄红素合成途径相关的PDS基因作为内标基因,在100个混合农杆菌样中,成功筛选到了PDS基因．     

Differential mode of action of thyrotropin-releasing hormone and enkephalin on the smooth muscle of rat duodenum

The tetrodotoxin-resistant relaxation to TRH or [met]-enkephalin (ENK) of the isolated segment of rat duodenum was used for studying the modes of action of these neuropeptides. ENK did not inhibit, while TRH inhibited, the spike potentials during the relaxation. The response to ENK was abolished by tetraethylammonium, whereas the response to TRH persisted. The response to TRH was abolished in a Ca-free medium, in which the response to ENK was observable. In K-free medium the effect of ENK was much diminished while TRH was still effective. In Na- or Cl-free medium the response to either TRH or ENK was not abolished. In the smooth muscle of the rat duodenum. TRH is likely to inhibit Ca ion influx, while ENK seems to exert its effect through increasing K ions permeability resulting in hyperpolarization.     

Mathematical analysis of genetic effects of low doses of ionizing radiation

The comparative study of effects of low doses of radiation on peripheral blood lymphocytes of persons occupationally exposed to radiation and non-exposed ones was carried out. The main attention was paid to radio-adaptive response forming under consistent exposure to low (0.05 Gy) and damaging (2 Gy) doses of gamma-irradiation. Noticeable heterogeneity in capacity for adaptive response forming in occupational group was revealed. The mathematical model adequate to experimental material was constructed using Kohonen neuronets.     

The isolation of a dimer of gene 8 protein of bacteriophage fd

Gene 8 protein was isolated in a highly aggregated form in aqueous solution from purified fd bacteriophage. Gene 8 protein was dissociated to a stable dimeric form in the presence of 10 mm-sodium deoxycholate. The dimer obtained in the presence of the detergent was stable to further dissociation by sodium dodecyl sulfate, and was estimated to have a 51% helical content on the basis of circular dichroism data. When the deoxycholate was removed, the dimers were observed by electron microscopy to self-associate to complex string-like structures. The dimer obtained is thought to be a result of one of the interactions between adjacent monomers in the model proposed by Marvin & Wachtel (1975).     

Kinetics of microbial oxidation of n-heptane. I. Characterization of the process

Utilization of n-heptane by a Pseudomonad was studied in pilot-size butch cultures. Optimal pH and temperature were determined by a factorial design and a medium based upon mineral uptake rates was formulated. High cell yields were obtained by volatilizing heptane in the incoming air and thereby achieving good hydrocarbon dispersion. Hydrocarbon carried by effluent gases was recovered and recycled. In cultures where pH is not controlled, decrease in the electrolytic conductivity of the medium was found to be indicative of viable cells and was used in monitoring bacterial propagation. If not checked, increase in salinity in pH controlled cultures was found to affect cell production negatively. Viscosity changes were not very significant. Heptane to aqueous medium ratio was found to affect oxygen supply to the system due to higher dissolved oxygen concentrations associated with hydrocarbons.     

Effect of Temperature on Radiosensitivity of Newcastle Disease Virus

Newcastle disease virus was irradiated at temperatures ranging from 2.2 to 60 C. An interaction between the thermal and ionizing energy was observed in the temperature region of 49 to 60 C. At 2.2 C, the hemagglutinin was considerably more radioresistant than the infectivity property. It is believed that radiation inactivation of Newcastle disease virus infectivity at low temperatures was due to nucleic acid degradation and at higher temperatures was due to protein denaturation.     

Role of acetate in sporogenesis of Bacillus cereus

Nakata, H. M. (Washington State University, Pullman). Role of acetate in sporogenesis of Bacillus cereus. J. Bacteriol. 91:784-788. 1966.-The distribution of radioactivity associated initially with acetate-2-C(14) was followed during sporogenesis of Bacillus cereus strain T. This was accomplished by replacing cells committed to sporulation into a chemically defined sporulation medium. It was observed that 65 to 70% of the initial radioactivity was incorporated into poly-beta-hydroxybutyrate, whereas 20 to 25% was found in other cellular constituents. Virtually no radioactivity was lost as C(14)O(2) during the first 5 to 6 hr after replacement. Then, a gradual evolution of C(14)O(2) coincident with poly-beta-hydroxybutyrate degradation, was observed until about the ninth hour. By this time, the polymer was essentially depleted, and the first spore structures were observed in stained preparations. The total amount of radioactivity lost as C(14)O(2) was 20 to 25%. The major portion of products derived from poly-beta-hydroxybutyrate was incorporated into the spores. As much as 17% of the radioactivity associated with the spores was found in dipicolinic acid. More than 50% was located in spore proteins, 20 to 25% in the hot 5% trichloroacetic acid-soluble fraction, 4 to 5% in the lipid fraction, and 15 to 20% in the cold 5% trichloroacetic acid-soluble fraction. These data, accounting for 70 to 75% of the initial radioactivity, confirmed the hypothesis that the major role of acetate, and subsequently of poly-beta-hydroxybutyrate, in sporulation of B. cereus T is to provide carbon precursors and energy for sporogenesis.     

日本三角涡虫热休克蛋白70(DjHSP70)C-端多肽表达及其抗血清制备

首先运用在线生物学软件对日本三角涡虫(Degusia japonica)热休克蛋白70(DjHSP70)氨基酸序列进行亲水区分析,发现该蛋白C-端含有较多亲水性氨基酸,然后以该段多肽序列为基础构建原核表达载体.采用PCR方法扩增450 bp cDNA片段,编码DjHSP70 C-端150个氨基酸多肽.将双酶切的cDNA...     

Effects of lipids on thermophilic anaerobic digestion and reduction of lipid inhibition upon addition of bentonite

Summary The effect of bentonite-bound oil on thermophilic anaerobic digestion of cattle manure was investigated. In digestor experiments, addition of oil was found to be inhibitory during start-up and the inhibitory effect was less pronounced when the oil was added in the form of bentonite-bound oil compared to when the oil was added alone. After adaption of the digestors, very rapid degradation of oil was observed and more than 80% of the oil was degraded within a few hours after daily feeding. In batch experiments, glyceride trioleate was found to be inhibitory to thermophilic anaerobic digestion when the concentrations were higher than 2.0 g/l. However, addition of bentonite (a clay mineral) at concentrations of 0.15% and 0.45% was found to partly overcome this inhibition. Addition of calcium chloride in concentration of 3 mM (0.033% w/v) showed a similar positive effect on the utilization of oil, but the effect was lower than with bentonite. Offprint requests to: I. Angelidaki