大豆低聚糖对肠道双歧杆菌和肠杆菌的促生长作用

目的:观察大豆低聚糖和所含糖对肠道菌群中双歧杆菌、肠杆菌体外促生长作用。方法:按1％大豆低聚糖、0．36％水苏糖、0．52％蔗糖、0．11％棉子糖含量配制培养液,分别接种各试验菌株,在0、12、24小时测定各培养液吸光度A值(分光光度计．550nm)和pH值。结果:经24小时培养,加大豆低聚糖的双歧杆菌标准株和临床分离株培养液A值分别为>1．5和1．307,大于肠杆菌标准株和临床分离株的1．1和1．173,而其pH值小于肠杆菌;加水苏糖的双歧杆菌培养液A值为1．47,大于蔗糖的1．4和棉子糖的0．53。结论:大豆低聚糖促双歧杆菌生长作用大于促肠杆菌生长,水苏糖是促双歧杆菌增殖生长的主要成分。     

应用Coriolus vericolor 菌丝球脱色染料及印染废水的研究

对白腐真菌（Coriolus vericolor）产生漆酶进行了研究。发现该菌产漆酶的最适初始pH值为4．5。提高微量元素浓度或添加藜芦醇都可使C.versiclor的产酶能力增加,添加Tween80会有一定的抑制作用。采用C.versicolor菌丝球进行重复分批产酶试验,结果表明菌丝球的稳定性很好,同一批菌丝球可连续利用14次,平均每批酶活力可保持在6．72U／mL,产酶能力优于聚氨酯泡沫固定化菌丝。将粗酶液用要料的脱色降解试验,在酶活力为3．3IU／mL,酸性橙浓度为500mg/L条件下,经过24h反应,脱色率达到98．5％;对含弱酸大红和卡布龙红的印染废水进行脱色试验,脱色率也达到了93％。     

温特曲霉HD_1的鉴定及其对氧蒽类染料脱色特性的研究

从土壤中分离到1株染料脱色真菌,经鉴定命名为温特曲霉HD1（aspergilluswentiiWehmerHD1）.该菌对氧蒽类染料虎红具有很强的脱色能力。温度在28～40℃之间,HD1对虎红的脱色率为93～99％,最适脱色温度为33℃;pH值在4.0～8．0之间,其脱色率为89．3～98．8％,最适脱色pH值为6．0。培养基、碳源、氮源及接种量对其脱色率均有影响。该菌对虎红的脱色酶为组成酶,主要分布在细胞内。染料的加入能改变脱色酶在胞内外的分配比例,加速胞内脱色酶的合成。虎红脱色产物的紫外可见光光谱分析表明,可见光区544．8nm处的吸收峰完全消失,而紫外光区的吸收峰则减弱、移位、消失（244～277nm）或稍有增加（242nm以下）。     

除草剂二甲戊灵的真菌降解及其特性研究

富集分离了除草剂二甲戊灵降解真菌,并研究了其降解特性,结果表明,真菌可以降解二甲戊灵,利用富集培养的方法从环境中分离到16株能降解二甲戊灵的真菌。其中10株真菌5d内对100mg·L^-1二甲戊灵的降解率大于60％,以其中3株生理耐受能力强、降解能力高的真菌为例,研究了外加碳源浓度、初始pH值、二甲戊灵浓度和培养温度对真菌生长量和降解能力的影响,此3株真菌经鉴定分别属于土生曲霉组(Aspergillus terreus)、长梗串孢霉属(Monilochaetes)和烟色曲霉组(Aspergillus furnigatus),在外加碳源浓度为0．5％～1．0％的范围内,真菌生长量和降解率达到最大;在中性培养液中,3株真菌的生长量大,降解能力强;在浓度为100mg·L^-1时降解率和生长量都比较大,而绝对去除量随二甲戊灵浓度的提高而增加,在500mg·L^-1时达到最大;真菌的生长和降解需要适宜的温度,20～30℃培养时,降解率和生长量最大,可为农药污染治理及生产污水处理提供理论依据。     

西洋参细胞大量培养的研究

当西洋参细胞培养在Ms培养液中,KN0₃含量提高一倍而去掉NH₄NO₃。时细胞生长速率和皂甙产量分别比在正常培养液中提高65．1％和166．2％。黑节草寡糖素和人参寡糖素均有利于西洋参细胞的生长和皂甙含量的提高,尤其能增加Rg组皂甙的含量。西洋参细胞悬浮培养以生产皂甙收获的最佳时期为培养25天以上,其合成皂甙的高峰在细胞生长的对数期稍后出现。细胞悬浮培养和发酵培养过程中均未见pH值回升的现象。pH值稳定的发酵培养和pH值任其变化的培养相比,其皂甙含量,生长速率和生物量均要高。最后对细胞的培养方式进行了比较。     

亚硝化单胞菌（Nitrosomonas sp．）THD-1分离鉴定及高密度培养

从浙江舟山桃花岛近海海域分离筛选到一株高活性氨氧化细菌,命名为THD-1。菌株THD-1为革兰氏阴性,球状至椭球状,大小约为（0．5～0．8）μm×（0．7～1．3）μm;菌落呈无色透明状,针尖大小,边缘光滑;可在盐度为0～50％0的培养基中生长。16SrDNA序列比对表明,菌株THD—1与Nitrosomonas europaea ATCC25978^T的相似性为96．3％。培养液的pH值对菌体生长和氨氧化活性影响明显,当pH值降至6．0以下时,菌株的生长和氨氧化活性几乎完全被抑制,但这种抑制可通过回调pH值的方法解除;在所试的4种碱液中,碳酸氢铵调节pH值对菌体生长和氨活性改善效果最好。建立了菌株THD-1的分批补料式高密度培养方法,最终OD600可达0．214,最大活菌数可达7．5×10^8cells／mL。     

紫外线诱变选育聚丁二酸丁二醇酯（PBS）高降解活性菌株

以PBS降解菌HJ03（Alternariasp．）为出发菌株,通过紫外诱变,透明圈初筛及PBS薄膜复筛,获得一株降解能力增强且对温度和pH耐受力均得到提高的突变株HJ10。与出发菌株相比,HJ10在培养初期气生菌丝少,而培养7d时菌落致密且生长速度较快。经过连续继代培养7代后发现,突变株的降解活力保持了良好的遗传稳定性,其降解率较出发菌株提高百分比达14．4％以上;在最适降解温度范围内（25℃～30℃）和不适宜降解的温度条件下突变菌株Ⅻ10的降解率均高于出发菌株;各pH条件下,突变株对PBS的降解能力明显优于出发菌株,尤其在pH5．0时降解率提高了22．80％。     

模拟精炼糖厂废水云芝脱色及对多糖含量影响*

比较了4株不同云芝PVC0、PVCl、PVC2、PVC3对模拟糖厂废水的总脱色能力及对美拉德反应色素、碱降解色素及焦糖色素的降解能力;比较了添加色素培养对不同云芝菌株生物量及菌丝体多糖(PSK)产量的影响。结果表明,PvCO对模拟废水的脱色率最高,其在废水中培养的菌丝体眺含量虽然较PVC1稍低,但其生物量最大,PSK产量仍然最大。以PVCO为当选菌株进行实验,研究表明浓度75％实际废水的PVCO脱色率为53％,低于对模拟废水的脱色率71％,但两培养的PvCO生物量与PSK产量相当。     

脱色希瓦氏菌S12的铁还原性能研究*

从印染废水中分离得到了一株具有染料脱色功能的希瓦氏菌脱色新种。该菌能在厌氧条件下利用Fe3+作为末端电子受体获得能量,支持细胞生长。在pH8．0,温度30℃,柠檬酸铁800mg／L,乳酸钠2g／L,酵母抽提物0．5g／L的条件下,培养8h的过程中,菌体细胞量的增长完全与Fe3+的还原发展趋向一致。同时考察了碳氮源、乳酸钠、酵母抽提物、pH值和温度等方面对该菌株的生长和铁还原特性的影响。结果表明,菌体生长以LB为最好,以葡萄糖和乳酸钠为碳源时对铁还原有利。在酵母抽提物浓度4g／L范围内,菌体生长量和铁还原率     

pH值对大乳头水螅种群增长、无性生殖及3种抗氧化酶活力的影响

应用种群累积培养法,就培养液pH值对大乳头水螅（Hydra magnipapillata）的生存、种群增长、无性生殖以及水螅的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH—PX）3种抗氧化酶活力的影响进行了探讨。结果表明,水螅存活的pH上限为10．5,下限为4．0,水螅存活的最适pH范围为5．5～9．5;pH值对水螅种群增长有显著影响,种群密度及种群瞬时增长率均随pH的不同而明显改变。培养15d后,除了pn4．0时水螅种群为负增长外,其他pH梯度下的水螅种群为正增长,其中pH6．5时水螅种群密度最高。以pH6．5为起始点,随着培养液酸性或碱性的增强,水螅种群密度整体都呈递减趋势。水螅SOD活力的转折点在pH6．5,当pH值偏离6．5时（酸性或碱性增强）,水螅SOD活力整体呈明显上升趋势;但水螅GSH—PX和CAT活力的转折点却在pH7．0,当pH值偏离7．0时（酸性或碱性增强）GSH—PX和CAT活力整体呈明显下降趋势。pH6．5时水螅SOD活力最低与pH6．5实验组水螅的无性出芽生殖率最高之间可能存在一定的内在联系。本文研究结果可为实验室培养水螅提供适宜的pH值指标。     

Kinetic characteristics of extracellular catalase from Penicillium piceum F-648 and variants of fungi,adapted to hydrogen peroxide

A comparative kinetic study of extracellular catalases produced by Penicillium piceum F-648 and their variants adapted to H2O2 was performed in culture liquid filtrates. The specific activity of catalase, the maximum rate of catalase-induced H2O2 degradation (Vmax),Vmax/KM ratio, and the catalase inactivation rate constant in the enzymatic reaction (kin, s-1) were estimated in phosphate buffer (pH 7.4) at 30 degrees C. The effective constant representing the rate of catalase thermal inactivation (kin*, s-1) was determined at 45 degrees C. In all samples, the specific activity and KM for catalase were maximum at a protein concentration in culture liquid filtrates of 2.5-3.5 x 10(-4) mg/ml. The effective constants describing the rate of H2O2 degradation (k, s-1) were similar to that observed in the initial culture. These values reflected a twofold decrease in catalase activity in culture liquid filtrates. We hypothesized that culture liquid filtrates contain two isoforms of extracellular catalase characterized by different activities and affinities for H2O2. Catalases from variants 5 and 3 with high and low affinities for H2O2, respectively, had a greater operational stability than the enzyme from the initial culture. The method of adaptive selection for H2O2 can be used to obtain fungal variants producing extracellular catalases with improved properties.     

Mechanism of the reaction of hydrated electrons with ferrocytochrome c.

1. The hydrated electron reacts with ferrocytochrome c to form an unstable intermediate. This intermediate decays in a first-order manner to give, in the first instance, a product which has a similar absorption spectrum in the range 400-610 nm as normal ferricytochrome c. 2. At 21 degrees C the rate constant for the reaction of hydrated electrons with ferrocytochrome c at pH 7.4 (2 mM phosphate buffer) is (3.0 +/- 0.3) = 10(10) M-1 - S-1. As the pH is increased above pH 8.0 the rate constant steadily decreases. The dependence of the rate constant on pH can be explained if ferrocytochrome c has a pK of around 9.2. 3. At 21 degrees C and pH 7.4, the rate constant for the decay of the intermediate is (1.40 +/- 0.15) - 10(5) S-1. This reaction shows no pH dependence in the range 6-2-11.0. 4. A mechanism is proposed whereby the central metal atom of the ferrocytochrome c is oxidased and a thioether bond is reduced. The resulting ferricytochrome c species then slowly develops an absorbance at 606 nm due to the attack of the sulfhydryl group on the haem.     

Callus induction and adventitious organogenesis of kenaf (Hibiscus cannabinus L.)

Callus production along with caulogenesis and rhizogenesis were obtained from internodal stem explants of kenaf (Hibiscus cannabinus L.) after 4 weeks in culture. Murashige and Skoog medium was used for two 4×4 matrix experiments designed to determine suitable growth regulator combinations (NAA/BAP or 2,4-D/kinetin) and concentrations (0.1, 0.3, 1.0, 3.0 mg/L). The most abundant callus production was observed at 0.3/3.0 and 1.0/3.0 mg/L 2,4-D/kinetin and at 1.0/1.0 and 3.0/1.0 mg/L NAA/BAP. Rhizogenesis was most extensive with NAA/BAP at concentrations of 0.1/3.0 and 0.3/ 3.0 mg/L. Adventitious shoots developed on both auxin/cytokinin matrixes when each concentration was at 0.3 mg/L or less. These protocols will facilitate the development of in vitro approaches to kenaf improvement and the study of certain host-pathogen interactions.Abbreviations MS Murashige and Skoog (1962) medium - 2,4-D 2,4-dichlorophenoxyacetic acid - BAP 6-benzylaminopurine - NAA 1-naphthyleneacetic acid - SDS sodium dodecyl sulfate     

Assessment of the changes of 2,4-dichlorophenoxyacetic acid concentrations in plant tissue culture media in the presence of activated charcoal

The rate of adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) by activated charcoal (AC) from liquid and semi-solid tissue culture media was determined using 2-[¹⁴C]-2,4-D. In liquid medium 99.5% of the added 2,4-D (10^-4 M) was adsorbed by AC (2.5 gl^-1) within 5 days of preparation of the medium. Higher 2,4-D levels of reduced AC concentrations increased the level of available 2,4-D in the medium and extended the period necessary for the level of 2,4-D in the medium to become stabilized. In semi-solid medium the rate of adsorption of 2,4-D by AC was considerably reduced. A stable ratio of gel/2,4-D:AC/2,4-D was only reached after 10 to 20 days, depending on the 2,4-D concentration used. Low pH levels and maintenance of the medium at higher temperatures (20–30°C) accelerated the adsorption of 2,4-D by AC. In vitro tissue cultures of coconut palm showed marked differences in their growth response according to the age of the medium used and the associated variations in 2,4-D concentrations.Abbreviations AC activated charcoal - BAP 6-benzylamino-purine - 2,4-D 2,4-dichlorophenoxyacetic acid     

Role of inoculum preparation and density on the bioremediation of 2,4-D-contaminated soil by bioaugmentation

The effect of inoculum preparation and density on the efficiency of remediation of 2,4-dichlorophenoxyacetic acid (2,4-D) by bioaugmentation was studied in non-sterile soil. A 2,4-D-degrading Pseudomonas cepacia strain (designated BRI6001) was used initially in liquid culture to determine the effects of pre-growth induction and of inoculum density. The time for complete 2,4-D degradation was reduced by 0.5 day for each log increase of inoculum density. In mixed (BRI6001 and soil bacteria) liquid cultures, a competition effect for 2,4-D became apparent at low inoculum levels (less than 10 10⁵ cfu/ml BRI6001 for 10⁸ cfu/ml soil bacteria) but only when the soil bacteria included indigenous 2,4-D degraders. In static non-sterile soil, the effect of inoculum density on 2,4-D degradation was comparable to that in liquid culture but only at high inoculation levels. At lower levels, a biological effect for 2,4-D degradation became apparent, as was observed in mixed liquid cultures, whereas at intermediate levels, a combination of biological, physical and chemical factors decreased the efficiency of bioaugmentation. The acclimation period for 2,4-D degradation in soil bioaugmented with BRI6001 reflected mainly the time required for cell induction and, presumably, for overcoming the physical limitation of diffusion of both 2,4-D and added bacteria in the soil matrix. Correspondence to: R. SamsonISSUED AS NRCC 33848     

白Pian体细胞胚悬浮培养的动力学研究

白(ＰｉｃｅａｍｅｙｅｒｉＲｅｈｄ.ｅｔＷｉｌｓ.)是我国特有的云杉属树种,在林业生产和环境绿化中均具有重要地位。其体细胞胚胎发生的研究,一方面可用于优良种质的大规模快速繁殖,为植树造林和园林绿化提供优质苗木;另一方面可作为遗传转化的再生系统,进行树种遗传...     

Influence of environmental factors on 2,4-dichlorophenoxyacetic acid degradation by Pseudomonas cepacia isolated from peat

A Pseudomonas cepacia, designated strain BRI6001, was isolated from peat by enrichment culture using 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole carbon source. BRI6001 grew at up to 13 mM 2,4-D, and degraded 1 mM 2,4-D at an average starting population density as low as 1.5 cells/ml. Degradation was optimal at acidic pH, but could also be inhibited at low pH, associated with chloride release from the substrate, and the limited buffering capacity of the growth medium. The only metabolite detected during growth on 2,4-D was 2,4-dichlorophenol (2,4-DCP), and degradation of the aromatic nucleus was by intradiol cleavage. Growth lag times prior to the on-set of degradation, and the total time required for degradation, were linearly related to the starting population density and the initial 2,4-D concentration. BRI6001, grown on 2,4-D, oxidized a variety of structurally similar chlorinated aromatic compounds accompanied by stoichiometric chloride release.     

Quantitative determination of besifloxacin, a novel fluoroquinolone antimicrobial agent, in human tears by liquid chromatography-tandem mass spectrometry

A rapid and sensitive method was developed using high-performance liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) for the quantification of besifloxacin in human tears using sparfloxacin as the internal standard (IS). Besifloxacin was extracted from human tear samples using an ammonium formate buffer at pH 3.25. The method was validated over a concentration range of 2-2000 ng/mL, with a total run time of less than 4 min. The overall intra- and inter-day precision for this method was less than 6%. The method was used to measure besifloxacin concentrations in tear samples collected after topical ocular administration to humans; besifloxacin concentrations were 610+/-540 microg/g (15 min) and 1.60+/-2.28 microg/g (24h).     

Effect of HEPES buffer systems upon the pH, growth and survival of Mycoplasma mycoides subsp. mycoides small colony (MmmSC) vaccine cultures

The use of a buffer system based on N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid] (HEPES), in conjunction with standard Gourlay's culture medium was investigated for the growth and maintenance of Mycoplasma mycoides subsp. mycoides SC vaccine strain T(1)44. When the initial pH of the culture medium was adjusted to 8.0, 0.075 M HEPES-NaOH was found to be sufficient to prevent the pH falling below 7.1 at any stage during the growth cycle, even in the presence of 0.5% glucose. Compared to growth in standard unbuffered Gourlay's medium, the final culture titre was found to be one log(10) higher, at 10(11) colour changing units (CCU) per ml, and considerably extended culture survival was observed at 37 degrees C. The titre remained above 10(10) CCU ml(-1) for 4 days, and above 10(8) CCU ml(-1) in excess of 1 month. After 4 month's storage at 37 degrees C the titre had fallen to 5x10(4) CCU ml(-1). In contrast, no viable bacteria could be detected in standard unbuffered medium 3 days after the onset of stationary phase, at which point the pH had dropped to 5.4. No significant difference in growth rate between the two media was observed. Adoption of a HEPES-NaOH buffer system by African vaccine manufacturers should require minimal changes to current formulations and procedures, and should enhance both the final titre and thermostability of freeze-dried and liquid broth vaccines against contagious bovine pleuropneumonia (CBPP).     

黑磷纳米片光催化甲基橙降解机理

偶氮废水大量排放到环境中会对生态系统和人类健康造成严重威胁,发展偶氮染料废水的高效处理技术具有实际意义。光催化法由于工艺简单、处理彻底等优点具有应用前景。本研究利用液相剥离法制备黑磷纳米片(LBP),以甲基橙(MO)为例,考察LBP对偶氮染料的光催化能力;利用淬灭及荧光探针试验判断体系中参与反应的主要瞬态物种;结合液相色谱-质谱的产物鉴定结果,阐明光催化降解机理。结果表明: MO在酸性(pH=3.0)和碱性(pH=11.0)条件下的降解速率(k_obs)高于中性条件下(pH=7.0)。LBP光照下产生羟基自由基(·OH)进攻偶氮键使双键断裂生成中间产物,后者被·OH继续氧化,生成主要降解产物N,N-二甲基-4-(2-对苯甲基肼)苯胺、2-二甲胺基-5-((4-(二甲胺基)苯基)二氮基)苯酚和N,N-二甲基-4-硝基苯胺。