水稻土中半胱氨酸分解产生含硫气体的研究

在室内培养条件下,测定了水稻土中含硫气体的释放．结果表明,该土壤中有硫化氢(Ｈ２Ｓ),羰基硫(ＣＯＳ),二甲基硫(ＤＭＳ)三种气体释放．当土壤中加入半胱氨酸后,ＣＯＳ和Ｈ２Ｓ气体的浓度有了明显增加,并有ＣＳ２和ＣＨ３ＳＨ测出,而ＤＭＳ的浓度变化不大．这些结果表明半胱氨酸的分解可能是 ＣＯＳ,Ｈ２Ｓ,ＣＳ２和 ＣＨ３ＳＨ的产生源之一．在好氧(正常大气)条件下,Ｈ２Ｓ,ＣＯＳ,ＣＳ２和ＣＨ３ＳＨ的释放量低于厌氧(氮气氛围)条件下的释放量,ＤＭＳ则高于厌氧条件下．这表明水稻土中半胱氨酸分解产生 Ｈ２Ｓ,ＣＯＳ,ＣＳ２和 ＣＨ３ＳＨ需较强的还原条件,产生这四种气体的微生物需要严格的厌氧条件．产生ＤＭＳ的微生物则比前者需要高一些的含氧量．在光照条件下,各含硫气体的释放量普遍高于无光照条件下的释放量．释放含硫气体的大多数微生物适宜的含水率为５０%且对土壤的ｐＨ值有一定要求．     

光合细菌促菠菜生长机理初探

对光合细菌（ Ｐ Ｓ Ｂ） 菌液经稀释后喷施叶面可促进菠菜生长的机理进行了初步研究,发现施用 Ｐ Ｓ Ｂ 菌液后,可使菠菜叶中叶绿素含量增加１０ ．５５ ％ ,使 Ｃ Ｏ２ 的吸收率和光合强度分别提高６１ ．９９ ％ 、１３ ．８ ％ ,使二磷酸核酮糖羧化酶（ Ｒ Ｕ Ｂ Ｐ） 活力增强３４ 倍． Ｐ Ｓ Ｂ菌液还可改变地壤中微生物菌群的组成：细菌、固氮菌、放线菌数量增多,真菌量减少．提示：光合细菌是通过提高菠菜自身的光合效率及增加土壤肥力来起到促生长作用的．     

汞胁迫对小麦幼苗抗氧化酶活性的影响

通过营养液培养实验,研究了小麦幼苗在遭受汞胁迫后,地上部及根系抗氧化酶活性的变化．试验表明:小麦幼苗受到汞胁迫后,地上部及根系的超氧化物歧化酶(ＳＯＤ)的活性均显著增加,过氧化氢酶(ＣＡＴ) 的活性也比对照有所增强,但不如ＳＯＤ酶变化迅速,表明ＳＯＤ酶活性是小麦幼苗遭受汞胁迫时比较敏感的生物标记物．但是,小麦幼苗地上部及根系的丙二醛(ＭＤＡ) 含量仍均比对照显著升高,表明小麦幼苗的膜系统受到了一定程度的破坏．试验同时还反映出,汞胁迫对小麦幼苗根系的影响强于对地上部的影响．     

马氏甲烷八叠球菌S－6的一个染色体区段的表达、序列分析和结构分析

用一组多克隆抗体对马氏甲烷八叠球菌（Ｍｅｔｈａｎｏｓａｒｃｉｎａｍａｚｅｉ）Ｓ－６菌株的基因组ＤＮＡ文库进行了筛选．仅选出ｐ６０Ａ克隆能对马氏甲烷八叠球菌中可发生细胞形态学变化菌株的抗血清发生阳性反应．对ｐ６０Ａ克隆的双链ＤＮＡ进行了序列分析．识别出一开式阅读框架（ｏｐｅｎｒｅａｄｉｎｇｆｒａｍｅＰ，ＯＲＦＰ）．表达的蛋白是ＯＲＦＰ编码的蛋白的３倍，并得到ＯＲＦＰ蛋白的三聚体，在ＳＤＳ－ＰＡＧＥ中表现出整体蛋白的迁移行为．同时，此表达蛋白抗１０％ＳＤＳ，６ｍｏｌ／Ｌ尿素及热处理．基因结构分析表明，ＯＲＦＰ具有与Ｍ．ｂａｒｋｒｉｍｃｒＡ有同源性的核糖体结合位点和一个与甲烷细菌启动子共有序列相似度达７７％的启动子序列．使用参照序列分析表明，由ＯＲＦＰ演绎的氨基酸序列，具有高密度的带电荷的氨基酸和占优势的β－层迭构型．对此表达蛋白作了Ｎｅｕｒｏｓｒｏｒａｃｒａｓｓａ的ｐｏｒｉｎ蛋白抗血清试验，以研究其可能功能．检验了Ｍ．ｍａｚｅｉＳ－６细胞的蔗糖梯度制备物，对此原细胞中的ＯＲＦＰ蛋白作了定位．结果表明，ＯＲＦＰ蛋白可能是一种古细菌Ｐｏｒｉｎ，其在Ｍ．ｍａｚｅｉＳ－６中的表达，可能象大肠杆菌那样与渗透压调节有关．     

光合细菌光合产氢机理研究进展[综述]

７０年代以来，随着全球性的能源危机和温室效应的加剧，无污染、可再生的氢能的研究开发日受重视．物制氢技术是氢能开发研究的一项重要内容．至今已知的具产氢活性的微生物有“光合细菌”（ｐｈｏｔｏｓｙｎｔｈｅｔｉｃｂａｃｔｅｒｉａ，ＰＳＢ）、藻类（ａｌｇａｅ）和非光合细菌（ｎｏｎｐｈｏｔｏｓｙｎｔｈｅｔｉｃｂａｃｔｅｒｉａ）［１］．由于ＰＳＢ光合产氢的速度要比藻类快，能量利用率比非光合细菌高，且能将产氢与光能利用、有机物的去除有机地耦合在一起，因而得到了众多研究者的关注．本文就ＰＳＢ的产氢的机理及影响产…     

土壤中水溶性有机碳与铜的相互影响

通过向土壤溶液中加入Ｃｕ２＋和可溶性有机碳(ＤＯＣ),研究它们之间的相互作用．结果发现,加入铜可以显著改变土壤水溶性有机碳(ＷＳＯＣ)的吸着平衡,并降低了其水溶性．影响程度在０．８ｍｍｏｌ·ｌ－１Ｃｕ以下随铜浓度的增加而增加．加入０．５ｍｍｏｌ·ｌ－１铜的土壤中 ＷＳＯＳ含量从 ０．２７ｍｇ Ｃ·ｇ－１降至０．０４７ｍｇ Ｃ·ｇ－１,吸着系数从６．６×１０－３ｌ·ｇ－１降至３．３×１０－３ｌ·ｇ－１．另一方面,用Ｆｒｅｕｎｄｌｉｃｈ方程描述铜离子在土壤中的吸附行为(液相浓度单位取ｍｍｏｌ·ｌ－１,固相浓度取ｍｍｏｌ·ｇ－１土),ｋ＝９．ｌ×１０－３;ｎ＝３．４０． 加入ＤＯＣ后,ｋ＝９．２×１０－３;ｎ＝３．６６,没有明显改变土壤对铜的吸附性能．加入小同浓度的ＤＯＣ,结果仍说明该浓度范围内ＤＯＣ(＜８ｍｇ Ｃ·ｌ－１)的加入没有明显改变土壤对铜的吸附性能．     

一种由质粒编码的葡萄球菌素的特性

从５８株具不同质粒谱的抗生素抗药性金黄色葡萄球菌中经筛选得菌株８５０４１．它所产生的抗菌活性物质能抗热７５～８０℃１ｈ；对蛋白分解酶敏感，包括胰蛋白酶、蛋白酶Ｅ、蛋白酶Ｂ．Ｐ，抗ＤＮａｓｅ及ＲＮａｓｅ；抗菌谱显示，在４株葡萄球菌类中只对金黄色葡萄球菌２０９Ｐ有抗菌活性，而对４株肠道菌及枯草芽胞杆菌无作用．据此认为，该抗菌物质属细菌素（葡萄球菌素）．用ＳＤＳ及４３℃处理产细菌素菌株，进行质粒消除试验及其质粒ＤＮＡ琼脂糖凝胶电泳，证明菌株８５０４１有一个Ｍｒ≈２４．４×１０６的产细菌素质检．     

蜂窝陶瓷表面预处理对催化剂性能的影响

应用溶胶－凝胶技术对蜂窝陶瓷载体进行涂层,以ＣＯ氧化作反应模型,考察了浸渍次数、分散剂及Ｌａ,Ｃｅ,Ｚｒ,Ｙ,Ｃｏ等组分对催化剂活性的影响,同时考察了Ｌａ２Ｏ３对催化剂耐热性能的影响．实验表明:两次浸渍的催化剂活性较高,浸渍原液中加入分散剂提高了催化剂对ＣＯ的氧化活性,使最低完全转化温度降低了１３℃左右．在Ｌａ,Ｃｅ,Ｚｒ,Ｙ,Ｃｏ等组分中,Ｃｅ是最有效的活性助剂,当ＣｅＯ２含量占Ａｌ２Ｏ３涂层的１８%时,催化剂的活性最好．而Ｌａ和Ｚｒ的加入对催化剂活性无明显作用,Ｙ和ＣＯ的加入则降低了催化剂的活性．在７００℃下７ｈ的热老化实验表明:Ｌａ２Ｏ３的加入对催化剂热稳定性无明显影响,但是,１０５０℃温度下２４ｈ热老化后的活性评价表明:Ｌａ２Ｏ３的加入对催化剂热稳定性作用显著,与未加Ｌａ２Ｏ３的催化剂相比,最低完全转化温度降低了１５℃左右．     

ICP—MS法对国标小麦粉中15种稀土元素的定值研究

本文报道采用ＨＮＯ３＋ＨＣｌＯ４溶样，小麦粉标样ＧＢＷ０８５０３中１５种超痕量稀土元素定值的ＩＣＰ－ＭＳ应用研究，造反了仪器最佳操作参数，选择Ｒｅ内标可补偿基体效应，方法检出限为０．００７－０．０２６ｎｇ．ｍｌ＾－１，加标回收率为９５－１０３％，ＲＳＤ为２．５－４．８％，方法快速、灵敏、准确。     

不同电场对大豆种子萌发的影响

分别对大豆种子进行低压电场长期处理和高压电场短时处理 ,测定了不同电场处理后种子发芽势、浕 -淀粉酶和过氧化物酶活性、可溶性蛋白含量以及种子超弱发光的变化 .发现低压长期处理 (± 0 .2～ 1.0kV/cm ,每天 8h)对大豆种子的萌发没有明显影响 ,高压短时处理 (2～ 6kV/cm ,30min)能促进种子萌发 ,显著提高种子的发芽势、浕 -淀粉酶、过氧化物酶活性和可溶性蛋白含量 ,高压短时处理吸胀种子比处理干种子的效果更为明显 .短时高压电场处理后 ,种子的超弱发光明显增强 ,并且种子超弱发光的变化与生理生化指标的变化具有显著相关性 ,提示超弱发光有可能成为一种准确、快捷、灵敏筛选种子最佳电场处理剂量的物理指标 .图 1表 3参 17     

Photoinduced degradation of sulfonamides,kinetic, and structural characterization of transformation products and assessment of environmental toxicity

This study focuses on the degradation of the sulfonamide antibiotics, sulfadiazine, sulfamethazine, sulfamethoxazole, and sulfathiazole, using ultraviolet irradiation in various conditions. Different pHs were investigated in combination with the addition of hydrogen peroxide and further oxygen removal. High-performance liquid chromatography electrospray ionization ion-trap mass spectrometry was used to identify and elucidate degradation products and to establish concentration–time curves. Previously unknown degradation products could be characterized. Reaction rate constants of all compounds and transformation products were determined. The parent sulfonamides decayed according to first-order kinetics, while the concentrations of the transformation products varied with time according to a subsequent reaction of an intermediate product. Quantum efficiencies were analyzed for mechanistic purposes. As example, sulfamethoxazole was added to effluents from a wastewater treatment plant and irradiated. Phototoxicity and environmental hazard were assessed through quantitative structure-activity relationship computations. In addition, the minimal inhibition concentrations were determined for Pseudomonas fluorescens and Bacillus subtilis. Conclusions for UV-C irradiation as a fourth purification wastewater treatment stage were derived.     

Spectral composition of bioluminescence of epipelagic organisms from the Sargasso Sea

The spectral characteristics of single identified epipelagic sources of bioluminescence from the western Sargasso Sea were measured with an optical multichannel analyzer (OMA) system during the April, 1985, Biowatt cruise. The emission spectra of specimens representing 45 species from 8 phyla were measured. Peak bioluminescence emissions typically occurred between 440 and 500 nm, in the blue region of the visible spectrum. Three exceptions involved emission in the green, yellow, and red spectral regions. Intraspectific variability in spectra, was noted in several species. One shrimp species exhibited two modes of light emission, each with different emission spectra. Other cases involved dynamic color shifts of 10 to 14 nm; the source of the spectral variability is unknown, but may involve optical filtering or differences in the color of luminescence from multiple sites of light emission. Measurements from independent samples of unsorted plankton revealed different spectral distributions. This suggests that the spectral emissions of bioluminescence in the upper water column will vary, based on species assemblage.     

Coelenterazine distribution and luciferase characteristics in oceanic decapod crustaceans

Coelenterazine biosynthesis has recently been demonstrated in the developing eggs of the decapod Systellaspis debilis. The cellular source of coelenterazine and the potential for biosynthesis in adult decapods, however, have not been fully investigated. We have conducted a systematic study of coelenterazine content in >230 individual decapods representing 19 species of Oplophoridae and 22 species from other families. We show for the first time that coelenterazine is responsible for both secretory and photophore luminescence in the same decapod. Tissues associated with secretory luminescence (hepatopancreas and stomach) in the Oplophoridae contained almost 3 orders of magnitude more coelenterazine (mean value=2154 pmol per specimen) than cuticular photophores (mean value=8 pmol per specimen). Coelenterazine content increases by 2 to 4 orders of magnitude during the development of three species of Oplophoridae. Species of Oplophoridae contain an order of magnitude more coelenterazine than those of other families (mean value=154 pmol per specimen). Coelenterazine was also detected in 11 apparently nonluminous decapod species (mean value=200 pmol per specimen). S. debilis luciferase characterisation enabled a luciferase assay to be developed to facilitate studies of the environmental control of bioluminescence. We hypothesise that the coelenterazine requirement in secretory bioluminescence exceeds that which could be assimilated from the food-chain. The significant increase of coelenterazine during the life cycle of secretory decapods supports this hypothesis. Putative evidence for environmental control of coelenterazine luminescence is also reported.     

Luminescence from non-bioluminescent tissues in oceanic cephalopods

Several tissues (e.g. kidney, blood, digestive gland) in oceanic cephalopods which do not exhibit in vivo bioluminescence, luminesce when homogenized in the presence of air or when simply exposed to air in a vial (blood). The source of the luminescence appears to be a luciferin: treatment of kidney homogenates and blood with a photophore extract presumably containing luciferase resulted in a 20-fold increase in light production. Luminescence was also found in the renal fluid, which may be the source of luminescent clouds produced by squids. The variability in luminescence found in some tissues of cephalopods appeared to be related to feeding. Luminescence was also detected in the digestive glands of midwater octopods.     

新农药氯虫酰胺在醇液中的光解

分别以氙灯和紫外灯为光源,对氯虫酰胺在甲醇和乙醇中的光解动力学及降解机理进行了研究。结果表明,在氙灯和紫外照射下,氯虫酰胺在甲醇和乙醇中的光解符合一级反应动力学规律。在模拟太阳光氙灯辐射下,氯虫酰胺在甲醇和乙醇中的光解半衰期分别为1．58h和2．57h,而紫外光辐射下分别为1．49min和1．60min。采用LC-MS对氯虫酰胺光解产物进行分离和鉴定,推断氯虫酰胺在醇中的光解途径主要涉及到分子环合和重排生成光解产物A[2-（2-溴-4H-吡唑并[1,5．d]吡啶并[3,2-b]B,4]恶嗪-4-基亚氨基）-5-氯-N,3-二甲基苯甲酰胺]和B[2-（3-溴-1-（3-羟基吡啶-2-基）-1H-吡唑-5-基）-6-氯-3,8-二甲基喹啉-4（3H）-酮1。     

Counterillumination in the Hawaiian bobtail squid,<Emphasis Type="Italic"> Euprymna scolopes</Emphasis> Berry (Mollusca: Cephalopoda)

The mutualism between the Hawaiian bobtail squid Euprymna scolopes and the luminescent symbiont Vibrio fischeri has been used extensively as a model system for studies ranging from co-speciation and biogeography to gene regulation and the evolution of pathogenesis. In this association, the luminescent bacterium V. fischeri is housed in a complex light organ within the mantle cavity of E. scolopes. Prior hypotheses have assumed that sepiolid squids in general utilize the bioluminescence produced by their V. fischeri symbionts for counterillumination, a behavior that helps squid camouflage themselves by matching down-welling moonlight via silhouette reduction. This assumption, based solely on the morphology of the squid light organ, has never been empirically tested for Euprymna in the laboratory. Here, we present data demonstrating that E. scolopes can modify the intensity of light produced by V. fischeri in the light organ as down-welling light intensity changes. Bacterial bioluminescence from the light organ is directly correlated with down-welling light intensity, suggesting that E. scolopes individuals utilize and control V. fischeri luminescence for counterillumination.Communicated by P.W. Sammarco, Chauvin     

Effects of UV-A LED light irradiation on growth of cultured RAW 264.7 cells

The aim of this study was to examine the effects of ultraviolet A (UV-A) irradiation-induced damage on cultured macrophage RAW 264.7 cells and determine which components produced these manifestations. RAW 264.7 cells were irradiated with 365 nm UV-A using a light-emitting diode (LED). Cell viability and damage were determined using a calcein-AM and propidium iodide dual-staining assay and lactate dehydrogenase leakage, respectively. Intracellular reactive oxygen species (ROS) were measured by H₂DCF-DA. The components of ROS in each medium were measured using an electron paramagnetic resonance (EPR) spectrometer in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide (TPC). While UV-A irradiation for 2 min significantly suppressed cell growth, LDH leakage did not occur. Addition of N-acetyl cysteine restored inhibition of cell proliferation, and reduced intracellular ROS levels. The EPR signal in the presence of TPC increased with time but was decreased by sodium azide. In addition, a typical EPR spectrum was obtained in the presence of DMPO, indicating the presence of a hydroxyradical. The spectrum was diminished by L-histidine. Data suggest that ROS generated in cells or culture medium by UV-A irradiation is predominantly singlet oxygen, and this singlet oxygen suppressed cell proliferation.     

Latitudinal trends in size-dependence of bioluminescence in the midshipman fish Porichthys notatus

The bioluminescent fish Porichthys notatus (plainfin midshipman), has a discontinuous distribution along the Pacific coast of North America. The fish is present from Cape Mendocino southward to Baja California, Mexico, absent off the coast of Oregon, USA, and abundant, northward, in Puget Sound, Washington. Interestingly, the population in Puget Sound lacks the substrate (luciferin) necessary for the luminescence reaction and, despite possessing an otherwise fully functional photophore system, is nonluminescent. The California population of P. notatus is uniformly luminescent south of Monterey Bay, but 15% of the speciments tested from San Francisco Bay and the Gulf of the Farallons have been reported to be nonluminescent. Explanations for nonluminescent midshipman in both Puget Sound and the San Francisco Bay area have focussed on a dietary requirement for luciferin. To gain further insight into reasons for nonluminescence in the San Francisco Bay region, the distribution of bioluminescence in P. notatus was studied from Monterey Bay to Cape Mendocino during 1985. A complex pattern of bioluminescence was found, in which nonluminescent individuals reflected neither a local anomaly in the San Francisco Bay region nor a simple gradient of decreasing luminescence towards the northern end of the range of the California population. Instead, a distinct size-dependent component in luminescence capability of the fish was observed. Aspects of the life history of P. notatus and related factors which might influence the bioluminescence characteristics of this population are discussed.Please address all correspondence to Dr. F.I. Tsuji at the Osaka Bioscience Institute     

Photodegradation of chromophoric dissolved organic matters in the water of Lake Dianchi,China

Water samples were taken from Lake Dianchi, on the Yungui Plateau of southwest China, and experiments were conducted to simulate the photochemical degradation characteristic of chromophoric dissolved organic matter (CDOM) in the lake water. Three groups of experiments under different light conditions: ultraviolet (UV) light, visible light, and dark, were done and variations of fluorescence properties, UV absorbance, and dissolved organic carbon (DOC) concentrations during the experiments were analyzed to study the photodegradation process of CDOM with time. The result showed that light irradiation led to significant photochemical degradation of CDOM, resulting in changes in florescent properties, absorbance losses, decreases in aromaticity and average molecular weight, as well as decline in DOC concentration in the water. It was also observed that UV irradiation had greater effect than visible light did. However, various fluorophores had different sensitivities to the same irradiation condition, that is, protein-like fluorophore at the low excitation wavelengths is more sensitive to UV irradiation than the other fluorophores, and is more readily to undergo photo-degradation. In addition, visible light irradiation did not have significant impact on DOC in the water, with DOC concentration decrease by 5.57% –59.9% during the experiment time. These results may provide new knowledge on the environment behavior of CDOM in the water of Lake Dianchi.     

Dinoflagellate luminescence increases susceptibility of zooplankton to teleost predation

The burglar alarm theory of bioluminescence was investigated by determining predation rates of a nocturnal teleost predator,Porichthys notatus, on nonluminescent kelp mysids illuminated by dinoflagellate flashes, between the fall and spring of 1989/1990. Mysids (Holmesimysis costata) were placed in aquaria containing varying concentrations (0 to 40 cells/ml) of the dinoflagellatePyrocystis fusiformis and a single midshipman fish. Controls usedP. fusiformis during their luminescence-inhibited day phase. Mysid swimming movements readily stimulated dinoflagellate luminescence. Flashes and prey strikes were observed simultaneously by image-intensifying and infrared video cameras on a splitscreen monitor. Predation rates increased at dinoflagellate concentrations of 3 to 15 cells/ml and decreased below controls at levels>20 cells/ml. Videotape analysis showed that at low concentrations (2 to 5 cells/ml), strike success rates exceeded 75% if prey were previously illuminated by a flash, but dropped below 50% at higher cell densities. Increased predation was attributed to luminescence revealing prey position. The decrease at higher concentrations was considered to be due to greater flash frequency providing a more diffuse and confusing target. The study demonstrates the effects of secondary luminescence on zooplankton predation at normally encountered dinoflagellate concentrations.