Degradation of crude oil by a mixed population of bacteria isolated from sea-surface foams

A mixed bacteria population (EM₄) was isolated from foams formed on the surface of a zone chromically polluted by hydrocarbons (Gulf of Fos, French Mediterranean coast, October 1981). The population was able to degrade crude oil very effectively in the presence of sea water supplemented with nitrogen, phosphorus and iron. The percentage of hydrocarbon degradation was 81% at 30°C, pH 8, and partial oxygen pressure of 100%. After 12 d incubation, 92 and 83% of satured and aromatic compounds (mono-, di- and triaromatics) were degraded, respectively, as well as 63% of polar products and 48.5% of asphaltenes. Maximum degradation was attained at a sodium chloride concentration of between 400 and 800 mM with Population EM₄, which is constituted of 8 strains, four of which are weak halophiles. Bacterial growth on hydrocarbons induces the production in the culture medium of surface-active agents which are able to emulsify the substrate. There is high specificity between the nature of the growth substrate and such emulsifying activity, particularly as far as petroleum is concerned: only the culture medium from Population EM₄ is able to emulsify petroleum. These surface-active agents contain sugars and lipids (fatty acids, mono- and diglycerides). The foams, which always contain a high concentration of both hydrocarbons (100 to 180 mgl^-1) and bacteria that are able to grow on these types of substrates, have a strong emulsifying activity. Our results would seem to demonstrate the importance of biosurfactants in the elimination of hydrocarbons from polluted biotopes.     

Influence of cadmium on the growth of Agrocybe perfecta and two Pleurotus spp and translocation from polluted substrate and soil to fruitbodies

The presence of Cd in substrate (wheat straw) strongly depressed the growth and mineralization of substrate by Agrocybe perfecta. Pleurolus ostreatoroseus was only slightly depressed and Pleurotus sp. CCB 068 increased degradation by the two highest Cd concentration. Mineralization rate of fungal substrate were increased by indigenous soil flora. However increase in Cd concentrations added to the soil depressed mineralisation of organic matter. Cadmium also affected the fruitbody yield and only Pleurotus sp. was able to fructify in high Cd concentrations. Translocation and accumulation of Cd in fruitbodies increased with the increase of Cd concentrations in substrate.     

Size exclusion chromatography for the removal of pigments from extracellular ligninolytic enzyme extracts from decayed wheat straw

Solid-state fermentation of wheat straw was carried out by a native white rot basidiomycete Daedaleopsis flavida strain 5A. Extract prepared from the 12-day decayed wheat straw contained extracellular ligninolytic enzymes like manganese peroxidase (MnP), manganese-independent peroxidase (MIP), lignin peroxidase (LiP) and laccase along with straw-degraded products and pigments. Sephacryl S-200 size exclusion chromatography in 16/100 column was used for the separation of these ligninolytic enzymes and straw-degraded products and pigments. Recovery of pigment-free ligninolytic enzyme activities as protein was 40% of the total proteins loaded and specific LiP activity increased 34 fold after size exclusion chromatography. Thus accurate estimation of LiP by veratryl alcohol oxidation assay was possible only after the removal of interfering pigments. The reproducibility of size exclusion chromatography is adjudged satisfactory from the consistent results obtained after seven repetitive uses of matrices.     

Studies on antimicrobial activities of solvent extracts of different spices

The antimicrobial activities of the ethyl acetate, acetone and methanol extract of 12 plant species were studied. The extract of Capsicum annuum (red pepper) (fruit) Zingiber officinale (ginger) (root), Cuminum cyminum (cumin), Alpinia ficinarum (galingale), Coriandrum sativum (coriander), Cinnamomun zeylanicum Nees (cinnamomun), Origanum onites L. (thyme), Folium sennae (senna), Eugenia caryophyllata (cloves), Flos tiliae (lime), Folium menthae crispae (peppermint) and Piper nigrum (blackpepper) were tested in vitro against 2 fungi and 8 bacterial species by the disc diffusion method. Klebsiella pneumonia 13883, Bacillus megaterium NRS, Pseudomonas aeroginosa ATCC 27859, Staphylococcus aureus 6538 P, Escherichia coil ATCC 8739, Enterobacter cloaca ATCC 13047, Corynebacterium xerosis UC 9165, Streptococcus faecalis DC 74, Kluyveromyces marxianus, Rhodotorula rubra were used in this investigation. The results indicated that extracts of different spices has shown antibacterial activity in the range of 7-24 mm 30 microl(-1) inhibition zone Eugenia caryophyllata (clove), 7-20 mm 30microl(-1) inhibition zone Capsicum annum (red pepper) and Cinnamomun zeylanicum (cinnamon) bark, 7-18 mm 30microl(-1) inhibition zone Folium sennae (senna) leaves, 7-16 mm 30 microl(-1) inhibition zone Zingiber officinale (ginger) root, 7-15 mm 30microl(-1) inhibition zone Cuminum cyminum (cumin) seed, 7-14 mm 30 microl(-1) inhibition zone Folium menthae crispae (peppermint), Origanum onites (thyme) leaves and Alpinia ficinarum (galingale) root, 7-12 mm 30 microl(-1) inhibiton zone Piper nigrum (blackpepper), 7-11 mm 30microl(-1) inhibition zone Flos tiliae (lime) leaves, 7-8 mm 30microl(-1) inhibition zone Coriandrum sativum (coriander) to the microorganisms tested.     

四种植物提取物的杀螺效果研究

福寿螺是我国华南地区一种危害十分严重的外来入侵生物。采用分布广泛的四种植物：水蜈蚣（Kyllinga brevifolia Rottb.）、红花酢浆草（Oxalis corymbosa DC）、红叶乌桕（Euphorbia cotinifolia L.）和辣蓼草（Polygonum flaccidum Meissn.）作为原料,在实验室内通过人工研磨方法提取植物体内的有效成分作为药剂,分别对福寿螺幼螺进行室内毒杀及刺激其上爬的效果研究。结果表明：水蜈蚣提取物的杀螺效果不明显,而红花酢浆草、红叶乌桕、辣蓼草等三种植物提取物具有较好的杀螺效果。72h的毒性实验表明,这三种植物提取物在质量浓度为400mg·L-1时,均能全部杀死福寿螺幼螺;其中,红花酢浆草的杀螺效果最强,质量浓度为100mg·L-1时的杀螺率就达到80%,200mg·L-1的质量浓度下已能全部杀死福寿螺,红叶乌桕在200mg·L-1质量浓度时的杀螺率为56.67%,而在此质量浓度下辣蓼草仅为26.67%。另外,提取物刺激福寿螺上爬实验结果表明,红花酢浆草和红叶乌桕均有刺激福寿螺向上爬的作用,且红花酢浆草刺激作用稍强于红叶乌桕。综合杀螺和刺激福寿螺上爬作用的效果,可以得出在控制福寿螺上红花酢浆草和红叶乌桕是比较理想的备选植物。     

Effects of host cell extracts on cultures of endosymbiotic diatoms from larger foraminifera

Log phase endosymbiotic diatom species, Nitzschia valdestriata, N. laevis, N. panduriformis var. continua, N. frustulum var. subsalina and var. symbiotica, Amphora tenerima, Fragilaria shiloi and Navicula hanseniana, were aseptically exposed to an homogenate of freshly crushed foraminiferal host species (Amphistegina). To various degrees, depending upon endosymbiont species, the host homogenate affected the formation of new frustules of growing and dividing cells. F. shiloi was the most affected species. New cells were spheroids and had only vestiges of frustules or none at all. Fewer numbers of the other species tested (40 to 60%) were abnormal. The raphe and keel of affected Nitzschia spp. were usually curved and incomplete. Many cells were spherical. We infer that host substances are probably responsible for the maintenance of the frustule-less state in vivo and that if ingested potential endosymbionts escape digestion, they could become frustule-less after growth and cell division. Host homogenate also increased the levels of photosynthetate released by diatoms to their medium. N. valdestriata was stimulated to release 76% of its photosynthetate while other species tested were stimulated to release between one quarter to one half of their photosynthetate. Host homogenate was also effective in causing the release of 43% of the photosynthetate of a free-living diatom, Amphora sp., which was also tested in the experiment. The concentration of the metabolites released in the experiment was too low for us to identify by TLC.     

鼠尾藻和鸭毛藻水提液对三角褐指藻的抑制作用

调查了鼠尾藻Sargassum thunbergii和鸭毛藻Symphyocladia latiuscula水提液对三角褐指藻Phaeodactylum tricornutum 生长的抑制作用.结果表明,海藻水提液明显抑制三角褐指藻生长,并且这种抑制作用来自藻体活性物质(化感物质);鼠尾藻和鸭毛藻的化感物质既溶于水也溶于乙醇,随时间可能被三角褐指藻消耗尽或发生降解,因而抑制作用减弱以至消失,最大抑制发生在接种4 d.鼠尾藻和鸭毛藻水提液抑制三角褐指藻生长的半效应质量浓度(EC_(50,96h))分别为4.37g·L~(-1)和3.59g·L~(-1),暗示三角褐指藻对鸭毛藻水提液抑制的反应更敏感.     

铅锌矿冶区土壤酶活性特征研究

分析测试了铅锌矿冶区Pb、Zn、Cu、Cd复合污染条件下的土壤酶活性，分析了土壤重金属污染状况与土壤酶活性的相关关系。结果表明，随着采样点偏离废气排放口主导风向程度增大，Pb、Zn、Cu、Cd综合污染指数PI逐渐降低，土壤蛋白酶、脲酶、过氧化氢酶的活性逐渐增高且差异显著，变化程度中大到小的顺序为蛋白酶→脲酶→过氧化氢酶。剖面分布上，综合污染指数PI〉5的样地，基本呈现随土壤深度增加而土壤酶活性降低的趋势。蛋白酶、脲酶、过氧化氢酶的活性间呈极显著正相关，3种土壤酶活性与全磷呈极显著正相关，与有机质相关性较低。蛋白酶、脲酶、过氧化氢酶等土壤酶活性分布特征对矿冶区污染程度和土壤生态系统特性具有一定的指示作用。     

生物法-人工湿地组合工艺对小城镇混合污水氮素去除效果研究

在华南热带亚热带地区,利用生物法-人工湿地组合工艺（A/BCO-CW）处理小城镇片区混合污水。全年运行结果表明,A/BCO-人工湿地组合系统对TN和NH4-N具有好的处理效果,年均去除率分别为57.57%、87.73%,平均去除负荷量达到3.85和3.26g·m-2·d-1。A/BCO预处理系统在停留时间为3～6h条件下,对NH4-N去除效率达57.38%,好氧段充分曝气,有利于硝化过程的进行,有效地解决人工湿地因溶解氧不足造成的硝化过程受限制情况,减少了后续湿地所需面积的25%。在0.30～0.59m·d-1水力负荷率下,垂直流-表面流-水平潜流人工湿地组合系统对TN和NH4-N平均去除负荷达到了2.56、0.90g·m-2·d-1;TN、NH4-N去除速率常数为39.8和41.62m·yr-1,这些数值均处于文献中k值范围的高量程内。在进水NH4-N变动范围为6.27～18.8mg·L-1时,出水水质均能稳定达到GB3838—2002《地表水环境质量标准》的IV类水1.5mg·L-1的标准。通过探讨A/BCO-CW组合工艺用于混合污水处理效率,实现了A/BCO和CW二者间在处理氮素过程中的优势互补。     

薇甘菊浸提液对福寿螺主要器官组织损伤的扫描电镜观察

采用薇甘菊（Mikania micrantha H.B.K.）的乙酸乙酯浸提液对福寿螺（Pomacea canaliculata）进行浸杀,通过扫描电镜观察福寿螺头足部、外套膜及肝脏组织的损伤状况,探讨薇甘菊化感物质对福寿螺器官组织结构的影响。经过薇甘菊质量浓度为100mg·L^-1提取液浸杀2d后,福寿螺主要器官出现了明显的组织损伤。头足部肌肉组织出现明显的杂乱丝条状并有断裂,部分有侵蚀剥落,表现为较大的组织缺损;外套膜有大量的细胞被浸润,呈疏松不整齐的结构;肝脏表面粗糙,凹凸相间的皱褶形成起伏不平的组织,其间有深浅不一的裂痕,并有侵蚀孔状损伤。扫描电镜的观察结果可为探讨薇甘菊浸提液对福寿螺的毒杀机理提供一定的依据。     

Impact of biochar produced from post-harvest residue on the adsorption behavior of diesel oil on loess soil

The primary objective of this study was to investigate the effect of biochar, produced from wheat residue at different temperatures, on the adsorption of diesel oil by loess soil. Kinetic and equilibrium data were processed to understand the adsorption mechanism of diesel by biochar-affected loess soil; dynamic and thermodynamic adsorption experiments were conducted to characterize this adsorption. The surface features and chemical structure of biochar, modified at varying pyrolytic temperatures, were investigated using surface scanning electron microscopy and Fourier transform infrared analysis. The kinetic data showed that the adsorption of diesel oil onto loess soil could be described by a pseudo-second-order kinetic model, with the rate-controlling step being intraparticle diffusion. However, in the presence of biochar, boundary layer control and intraparticle diffusion were both involved in the adsorption. Besides, the adsorption equilibrium data were well described by the Freundlich isothermal model. The saturated adsorption capacity weakened as temperature increased, suggesting a spontaneous exothermic process. Thermodynamic parameter analysis showed that adsorption was mainly a physical process and was enhanced by chemical adsorption. The adsorption capacity of loess soil for diesel oil was weakened with increasing pH. The biochar produced by pyrolytic wheat residue increased the adsorption behavior of petroleum pollutants in loess soil.

     

Studies on underwater sounds III. On the mechanism of sound production and the underwater sounds produced by Linuparus trigonus

Linuparus trigonus V. Siebold were placed in a tank, with a hydrophone suspended in one corner, in order to investigate the mechanism of sound production and the under-water sounds released. Sounds were recorded by tape recorder and analyzed by means of sound spectrograph. L. trigonus emits creaky sounds by rubbing the protuberance of the antennal coxa against the white tubercle in front of its optic stalk. The protuberance of the coxa molds a hollow, with the opening covered by a thin membrane; this facilitates the production of under-water sounds. However, these sounds are produced only when the antenna is lifted. It is also possible to produce these sounds artificially using dead lobsters. When disturbed by external stimulus, L. trigonus flaps back and accelerates the repitition rate. The under-water sounds produced are a series of pulses, which can be divided into 2 groups: (1) The A type sound; this has a relatively slow repetition rate (10 to 80 times/sec) and is weak at the low frequency range below 3 kHz; the sounds, therefore, are manifested on the sonagram in a pattern consisting of some layers of frequencies which are almost constant. (2) The B type sound; this comprises a series of pulses which are powerful even at low frequency. The repetition rate is very high, and not recognizable on the sonagram.     

鼎湖山针阔叶混交林地表CH4通量

用静态箱-气相色谱法对鼎湖山针阔叶混交林的地表CH4通量进行了为期一年的原位观测和研究.结果表明,该林型土壤总体为大气CH4的吸收汇,通量年变化范围60～-120 μg·m-2·h-1,在雨季向旱季过渡的9、10月份,土壤对CH4的吸收较为强烈,而在冬季的1月份,吸收通量最小;凋落物层对该林型地表CH4的吸收没有明显的阻隔作用;多元回归分析发现CH4通量与地下5 cm温度显著相关,尤其是在土壤湿度变化不大的旱季,土壤表层温度为影响CH4通量的主导因子.     

Comparison of in vitro characteristics of and experimental lesions produced by a clinical and an environmental isolate of Aspergillus flavus

In the present study, two strains of Aspergillus flavus (one from a human corneal ulcer and one from the environment) were found to be strikingly similar in vitro in terms of thermotolerance, inability to grow in an anaerobic environment and in secreting proteinases; however, one obvious difference was that the clinical isolate produced 120 ppb of aflatoxin B1 in glucose salt medium while the environmental isolate did not produce this toxic metabolite. Alterations in the activities of acid phosphatase (ACP), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and glutathione-S-transferase were observed in the liver, kidney and serum in an experimental rat model, irrespective of whether the animal had been challenged with the clinical isolate or the environmental isolate of A. flavus. In rats that had been challenged with the clinical isolate, a significant decrease in the activity of kidney ALP was noted, whereas in rats that had been challenged with the environmental isolate, the reverse was observed. While these differential alterations may have occurred due to differences in the toxin-producing ability of the two isolates, further investigation is warranted to clarify whether other phenotypic, or genotypic, differences are also involved.     

湿地甲烷的产生、氧化及排放通量研究进展

甲烷研究已倍受科学界关注,不仅由于其对全球变暖的贡献仅次于二氧化碳,贡献率达25%,还因为单分子甲烷的增值潜势是二氧化碳的15~30倍.湿地是甲烷的重要来源,估计湿地生态系统对全球甲烷排放的贡献率约为20%,即为100~200Tg a?1.湿地甲烷在厌氧条件下产生,在土壤氧化层以及根际中部分氧化,然后通过土壤、水体和植物体排放到大气中去.就近10a来湿地甲烷产生、氧化、传输过程及其影响因素等的研究进展进行了综述.产甲烷菌的研究主要集中在其对环境因子的生理生态和分子生物学,尤其集中在稻田产甲烷菌的研究上,因此在深度和广度上都有待突破.产甲烷过程是一个复杂的生化过程,要对甲烷排放量估计、甲烷排放动态研究以及在甲烷排放建模等方面取得进展,必需在甲烷产生机制上进行突破.甲烷氧化菌的研究集中于菌群对环境的适应以及其自身氧化能力上,应用研究还不是很深入.甲烷氧化过程的研究已经有了一定的深度,但氧化过程具体机理的研究还有待进一步深入,这需要分子生物学以及基因组学等多学科的交叉.甲烷传输过程是研究甲烷排放动态的基础,目前相关研究较少,国内有关研究主要集中在稻田研究上,对高寒湿地的研究则几乎是空白.湿地甲烷通量的研究是目前温室气体研究的热点问题,但主要解决的问题是大气中甲烷气体浓度增加与湿地甲烷通量的关系.湿地甲烷通量是由多种因素决定的,对影响湿地甲烷通量的因素的研究相当丰富,特别是近年来对生物因素的关注.由于学科的发展,近10a在这方面的研究较之过去更为全面和系统.图1表1参68     

Studies on Rhizospheric Mycoflora of Tea (Camellia sinensis):In vitro Antagonism with Dominant Bacteria

The rhizospheres of established tea bushes have some specificcharacteristics which are associated with the long lived nature of teaplants,viz.,negative rhizospheric effect,lowering of soil pH,antagonistic activities among microbial communities and dominan…     

Effects of crude oil and chemical dispersant on photosynthesis in the brain coral Diploria strigosa

An eight-hour exposure of Diploria strigosa (Dana) to a mixture of Arabian Light crude oil (19 ppm) and the chemical dispersant “Corexit 9527” (1 ppm) in a flowing seawater system reduced photosynthesis by symbiotic zooxanthellae by 85%, while either oil or dispersant alone had no effect. The greatest effect of crude oil plus dispersant occurred in the incorporation of photosynthetic products into lipids. Synthesis of was esters and triglycerides, the major storage lipids, was particularly affected. Total carbon fixation was restored within 3–5 h after treatment, and lipid synthesis was restored within 5–24 h after exposure.     

Evaluation of endocrine disruption and dioxin-like effects of organic extracts from sewage sludge in autumn in Beijing,China

Study on effective disposal and utilization of sewage sludge has recently been the target of growing interest in China. However, potential risks are associated with the use of sludge due to its contamination with toxic organics, heavy metals and pathogenic microorganisms. In this study, a screening assessment was conducted on sewage sludge samples collected from 17 different sewage treatment plants in Beijing, based on a batch of in vitro bioassays, including a set of recombinant gene yeast assays for endocrine disruption, and an ethoxy resorufin-O- deethylase （EROD） assay using H4IIE cells for aryl hydrocarbon receptor （Ah-R） agonistic activities. Our results suggested that moderate levels of estrogen receptor agonistic activities （0.9 ng E2. g-1 to 6.8 ng E2. gl, dw）, but relative higher androgen receptor antagonistic activ- ities （nd to 45%）, progestin receptor antagonistic activities （nd to 80%） and Ah-R agonistic activities （1390 to 6740 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin （TCDD）·g-1, dw） were found in sewage sludge samples. However, there were no significant correlations between the toxic effects of sewage sludge and the sewage treatment processes. In addition, the 17β-estradiol （E2） equivalent quantity （EEQ） level of the sewage sludge was increased after the composting treatment, whereas the 2,3,7,8-tetrachlorodi- benzo-p-dioxin toxic equivalent quantity （TEQ） level of sewagesludge composted was much lower than that of sewage sludge.     

Detection of Escherichia coli in wastewater based on enzyme immunoassay

This research describes a fast detection method on the basis of enzyme-linked immunosorbent assay (ELISA) for Escherichia coli in drainage of wastewater treatment plants. Optimized conditions such as the reaction format (sandwich or direct), the concentrations of diluted horseradish peroxidase (HRP)-E. coli conjugate, and anti-HPR antibody and pretreatment of E. coli were studied. Those results showed that the linear range of detection for E. coli was 10 cfu/mL-6 × 10⁴ cfu/mL. Compared with conventional methods, it is a convenient and sensitive detection method with low cost.     

Protective effects of Peganum harmala extracts on thiourea-induced diseases in adult male rat

Cancers and hepatoprotective prevention using traditional medicines have attracted increasing interest. The aim of our study was to characterize the putative protective effects of ethanol and chloroform extracts of Peganum harmala on thiourea-induced diseases in adult male rat. We seek to determine the effects of these plant extracts on body weight, thyroid and endocrine cancer parameters. In addition the putative hepatoprotective effect was checked by the determination of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and the bilirubin level in the blood. Our data show that ethanol and chloroform extracts of Peganum harmala protected the animal against the carcinogenic effects induced by thiourea since neuron-specific enolase (NSE) and thyroglobulin (TG) levels were back to the normal range. In addition, the observed-hepatocytotoxicity after thiourea treatment was greatly reduced (AST and ALT activities were respectively 270 IU/l and 60 IU/l and in the same order of magnitude as in the untreated rats) as well as the bilirubin levels (6 micromol/l) especially for animals receiving the choroform preparation. Therefore we may suggest that extracts of Peganum harmala are efficient to reduce the toxicity induced by thiourea in male rat as far as the above parameters are concerned.