ACTION OF VISIBLE LIGHT ON ENZYMES IN CELL ENVELOPES OF MICROCOCCUS ROSEUS

Abstract— Envelopes were isolated from the carotenogenic bacterium Micrococcus roseus , which is subject to photodynamic killing in the presence of a photosensitizing dye but not in the absence of such a dye. Envelope preparations contained 88 per cent of the total cellular carotenoids, 20% of the NADH oxidase, 100 per cent of the ATPase and 30% of the succinic dehydrogenase activity. NADH oxidase activity in envelopes was stimulated 2–5-fold by light in the presence of dye; this was followed by inactivation. In the presence of dye, ATPase was inactivated by light and 25 per cent of the succinic dehydrogenase activity was lost. In the absence of dye, responses were extended over a longer period of time, but similar patterns were observed for the three enzymes, indicating that envelopes contain an endogenous photosensitizer(s). Carotenoid-deficient cells were obtained after growth in medium containing diphenylamine. But all three enzymes showed evidence of instability in envelope preparations, indicating that diphenylamine affects membrane structure in addition to inhibiting synthesis of colored carotenoids.     

THE PHOTOKILLING OF BLADDER CARCINOMA CELLS in vitro BY PHENOTHIAZINE DYES

The potential photodynamic therapy photosensitizers Methylene Blue, Azure C, Methylene Violet, Thionine, Methylene Green, Haematoporphyrin, Nile Blue A, chloroaluminium phthalocyanine and bis-aluminium phthalocyanine were examined for their photoeffects and dark toxicity against a human superficial bladder carcinoma cell-line. By examination of [3H]thymidine uptake into dye-treated cells after irradiation with a copper-vapour pumped dye laser, it was found that Methylene Blue was the most phototoxic and dark toxic of all the dyes tested, suggesting that the dye might be of some use as a topically applied photodrug for use in photodynamic therapy of superficial or early-recurring carcinomas.     

THE IN VIVO ASSOCIATION OF MANGANESE WITH THE CHROMOSOME OF MICROCOCCUS RADIODURANS

Abstract —Extremely high levels of paramagnetic manganese (Mn²⁺) which quench phosphorescent reactions have been found to inhibit the formation of thymine-containing dimers in M. radiodurans . Lowering the concentration of Mn²⁺ in the culture medium resulted in a lower intracellular concentration of Mn²⁺, an increase in the UV-sensitivity of this bacterium, and a larger photochemical yield of thymine-containing dimers. High levels of paramagnetic Mn²⁺ were not found in other test organisms which are more sensitive to UV-irradiation. One interpretation of our data is that in Micrococcus radiodurans Mn²⁺ may bind to the chromosome and thereby reduce the photochemical yield of thymine-containing dimers.     

聚乙烯醇固定化的微球菌AD3对除草剂阿特拉津的生物降解

从农药厂的工业废水和污泥的混合物中分离到高效降解除草剂阿特拉津的藤黄微球菌(Micrococcusluteus)AD3菌株。以聚乙烯醇(PVA)为包埋材料进行AD3菌株的固定化,对影响固定化细胞降解阿特拉津的因素(如阿特拉津浓度、温度、pH)和操作稳定性进行了研究。结果表明,在最适条件下(30℃、pH7.2、阿特拉津浓度500mg/L)固定化细胞的阿特拉津降解速度明显高于游离细胞。固定化细胞在低温、低pH和高阿特拉津浓度条件下的阿特拉津降解率,以及贮存和操作稳定性,也明显好于游离细胞。固定化细胞在15℃、pH7.2、阿特拉津浓度为500mg/L的条件下培养72h以后,阿特拉津降解率为90%,在相同条件下游离细胞的降解率仅为35%。固定化细胞在pH5.0、30℃、阿特拉津浓度为500mg/L的条件下培养72h以后,降解率为96%,在相同条件下游离细胞的降解率仅为40%。固定化细胞能够快速降解1000mg/L的阿特拉津,而游离细胞则不能。稳定性实验表明,固定化细胞重复使用30次以后其降解活力没有明显降低。     

SYNERGISTIC KILLING EFFECT IN PRE-UV-IRRADIATED MICROCOCCUS RADIOPHILUS

Abstract— Both the UV- and y-radiation survival curves of Micrococcus radiophilus are distinguished by large shoulders. However, a combination radiation treatment results in an enhanced killing effect. Pre-UV treatment is found to give a synergistic kill as compared to an additive kill when the sequence of radiation treatments is reversed.     

THE PHOTOINACTIVATION OF THE RESPIRATORY CHAIN IN SARCINA LUTEA (MICROCOCCUS LUTEUS) AND PROTECTION BY ENDOGENOUS CAROTENOID

Abstract. Irradiation of isolated membranes of Sarcina lutea (Micrococcus luteus) with blue light rapidly inactivated the respiratory malate oxidase system under aerobic but not anaerobic conditions. This inactivation was much faster than that seen in whole cells suggesting that the intact organism possesses protective mechanisms capable of preventing or repairing light damage. Three photosensitive sites have been detected by comparing the effect of blue light on membranes from the carotenoid-containing wild-type and a carotenoidless mutant. The sites have been identified as the initial malate dehydrogenase enzyme, a flavoprotein assayed by phenazine methosulphate reduction, a sulphydryl group associated with the dehydrogenase complex but not involved in phenazine methosulphate reduction and the respiratory quinone, menaquinone. Menaquinone was found to be sensitive only in carotenoidless membranes and not in membranes from the pigmented wild-type. Studies of the variation of photosensitivity with wavelength suggest that the three sites are sensitized by different chromophores and that the quinone acts as its own photosensitizer.     

PHOTOSENSITIVITY IN CAROTENOIDLESS MUTANTS OF MICROCOCCUS LUTEUS (SARCINA LUTE A): NON-PHOTODYNAMIC MENAQUINONE DESTRUCTION IN WHITE LIGHT

–The photosensitivity of a carotenoidless mutant strain has been examined in terms of its loss of viability and loss of menaquinone when subjected to high intensity visible light. Cell viability and menaquinone are protected by cyanide (an inhibitor of cytochrome oxidation), by malate (a substrate for the respiratory chain) and by nitrogen although the protection of menaquinone is less in nitrogen. Evidence is presented in support of the view that oxidised membrane-bound menaquinone is more photolabile in visible light than the reduced form. Loss of menaquinone is seen as the primary cause of death in these obligately aerobic carotenoidless cells and the role of oxygen as indirect by converting reduced menaquinone to the oxidised form. Evidence is also presented that the cause of cell death in red light in the presence of an exogenous photosensitizer, toluidine blue, is different from that in white light.     

IN VIVO EXCISION OF PYRIMIDINE DIMERS IS MEDIATED BY A DNA N-GLYCOSYLASE IN MICROCOCCUS LUTEUS BUT NOT IN HUMAN FIBROBLASTS

Abstract It has been previously shown that Micrococcus luteus possesses a pyrimidine dimer-specific endonuclease which in vitro , functions as both an endonuclease and DNA-glycosylase. To determine if these combined activities function in vivo , we have isolated and examined the excision products of UV-irradiated M. luteus . In addition, we have devised a procedure to isolate and examine the excision products from UV-irradiated human fibroblasts to determine if an endonuclease/glycosylase activity functions in the excision of UV-induced pyrimidine dimers in human fibroblasts. We find that, in vivo , an endonuclease/glycosylase mechanism is utilized extensively in the repair of pyrimidine dimers by M. luteus , but that human fibroblasts do not appear to use this mechanism.     

水中高锰酸盐指数测量不确定度的评定

对GB 11892 - 1989《水质　高锰酸盐指数的测定》中酸性高锰酸钾氧化法测定水中高锰酸盐指数的测量不确定度进行了评定。通过对测量重复性、滴定管、移液管、标准溶液浓度等影响测量结果的不确定度分量的分析和量化 ,求得水中高锰酸盐指数测定结果的相对合成标准不确定度为 1.10× 10 -2 。     

生活饮用水总硬度测量结果的不确定度评定

对乙二胺四乙酸二钠滴定法测定生活饮用水总硬度的测量不确定度进行评定。分析了测量重复性、标准溶液的浓度、滴定管、取样等因素对总硬度测量不确定度的影响,求得生活饮用水总硬度测定结果的相对合成标准不确定度为2.74×10-3。     

生物探针与脱氧核糖核酸的结合模式及其分光光度法测定的进展

对生物探针与脱氧核糖核酸（DNA）的结合模式及有机染料分光光度法测定DNA的研究进展进行了综述。引用文献71篇。     

铕测定方法的近期进展

对铕测定方法的近期进展作了评述，涉及的测定方法有荧光光度法、吸光光度法、原子发射光谱法、原子吸收光谱法、X-射线荧光光谱法、质谱法及伏安法等。还对该领域的研究动态作了简要讨论（引述文献59篇）。     

微量铽的萤光光度测定——铽与吡啶-2,6-二羧酸螯合物的萤光

铽与吡啶-2,6-二羧酸(以下简称DPA)形成螯合物的萤光有人从生物化学角度作过一些研究^[1],但对测定稀土氧化物中微量铽的研究未见报导。本文系统地研究了Tb³⁺-DPA螯合物萤光产生的条件,拟订了测定稀土氧化物中微量铽的萤光光度法,探讨了螯合物萤光强度与其组成的关系。     

乙醇辐解机理研究

本文研究了氧、温度和4-甲基-4-苯基-2-戊酮(Mpp)对乙醇辐解的影响。Mpp在实验使用的浓度范围内对乙醛的G值没有影响, G(2,3-丁二醇)值随Mpp浓度增加而下降, 最后达0.9恒值。使用Mpp求得原初过程形成的G_(H_2)=1.9, 动力学处理求得G_H=2.4, k_(12)/k_(11)=(11.9±1.8)×10~3。实验证明Mpp清除了体系中的H原子, 抑制了CH_3CHOH自由基的形成, 从而抑制了2,3-丁二醇的生成, 但不影响乙醛的产额。这一研究否定了传统文献所述的在γ辐解乙醇时相当量的羟乙基自由基歧化反应生成乙醛。本文还对乙醇γ辐解机理进行了讨论, 并求得了乙醇辐解的物料平衡。     

磷酸钙骨水泥水化机理研究进展

本文综述了Ca(H2PO4)2·H2O-Ca3(PO4)2-Ca4(PO4) 2O,Ca4(PO4)2O-CaHPO4,α-Ca3(PO4)2-少量β-TCP、HAP,β-Ca3(PO 4)2-CaHPO4·H2O-CaCO3及α-Ca3(PO4)2-Ca(H2PO4)2·H2O -CaCO3等几种主要磷酸钙骨水泥体系的特点和水化机理研究进展.     

聚全氟(乙烯-丙烯)树脂的力学性能研究

研究了四氟乙烯和六氟丙烯共聚物的熔融指数,抗张强度和耐应力开裂之间,以及端基和热稳定性之间的关系。发现:(1)在一定的共聚物组成和分子量分布情形下,共聚物的熔融指数和抗张强度的关系可表示为经验式:F=350—18.3(M_I);(2)熔融指数大于4的共聚物不耐热应力开裂;(3)共聚物经380℃热处理,其端基转变为-CF=CF_2后,已具有挤出成型所要求的热稳定性。     

硒酸酯多糖抗石英细胞毒性的研究

本文采用家兔肺泡巨噬细胞体外培养法，以ＡＲ－ＣＭ阳离子测定系统和荧光试剂Ｆｕｒａ－２，研究了石英细胞毒性与肺泡巨噬细胞胞胞浆游离Ｃａ＾２＋浓度（［Ｃａ＾２＋］ｉ）的关系，并以细胞存活率，乳酸脱氢酶活性和脂质过氧化物表征了由石英引起的ＡＭ毒性及硒酸酯多糖对其毒性的拮抗效应，初步讨论了硒酸酯多糖拮抗石英细胞毒性的可能机理。     

热塑性塑料熔体质量流动速率测量不确定度的评定

以聚乙烯为例讨论了热塑性塑料熔体质量流动速率测量不确定度的来源,依据JJF 1059-1999对熔体流动速率测试过程中的测量不确定度分量进行了分析和评定。7149型聚乙烯熔体质量流动速率测量结果的扩展不确定度为0.096 g/(10 m in)。     

卵磷脂抗石英毒作用的研究

本文采用家兔肺泡巨噬细胞(AM)体外培养法,以细胞内游离钙浓度([Ca~(2+)]_i)、细胞存活率、乳酸脱氢酶(LDH)和酸性磷酸酶(ACP)活性为指标,观察了卵磷脂、脑磷脂及现用防治硅肺药物克矽平(PVPNO)、柠檬酸铝等抗石英毒效果。结果表明:卵磷脂在所试各药物中效果最佳.初步探讨了卵磷脂拮抗石英细胞毒性的机理.卵磷脂有成为防治硅肺药物的可能性.     

差示扫描量热法测定聚乙烯结晶度的不确定度评定

采用差示扫描量热法(DSC)测定聚乙烯(PE)的结晶度，讨论了测定PE熔融焓过程中由测量重复性、称量过程及PE本身结构的不均匀性等因素所带来的不确定度分量，计算了测定PE熔融焓的合成标准不确定度及扩展不确定度和测定PE结晶度的扩展不确定度。采用Dsc法测定高密度聚乙烯(HDPE)和低密度聚乙烯(LDPE)结晶度的扩展不确定度均小于l％。