Enhancement of atrazine degradation by crude and immobilized enzymes in two agricultural soils

Contamination of soil, groundwater and surface water by atrazine is a worldwide concern. Arthrobacter sp. HB-5 is a high-efficiency atrazine degradation strain isolated by our laboratory. Crude enzyme extracted from HB-5 and immobilized enzyme made from crude enzyme on sodium alginate were introduced to atrazine-polluted soils to evaluate the degrading ability for practical use and to calculate the kinetics of atrazine degradation. Atrazine was applied at 10 mg/kg of soil. Brown soil or cinnamon soil samples with crude or immobilized enzyme were incubated at 25°C. Samples were collected every 24 h from 0 to 144 h to extract the residual atrazine and analyzed using gas chromatography. Results showed, at 144 h, that only about 10% of the initially applied amount of atrazine was left in the two soils, except in the control soil samples without crude or immobilized enzyme. Before 48 h of incubation, crude enzyme removed atrazine faster than the immobilized enzyme in each soil sample. However, after 120 h, degradation of atrazine reached a similar level with either treatment. Atrazine seemed to be removed more easily from cinnamon soil than from brown soil, and both crude and immobilized enzyme could be used. However, the immobilized enzyme is preferred for its stability.     

青藏高原土壤中一株低温原油降解菌的分离鉴定及其原油降解特性

从青藏高原班戈桥地区土壤中分离到一株能利用原油为碳源生长的细菌(BGQ-6). 通过16S rRNA基因序列比对及Biolog GEN Ⅲ鉴定板确定该菌株为Rhodococcus qingshengii. 将生长至对数期的菌株接入MM培养基, 10 ℃、150 rpm条件下培养15 d后, 通过GC法检测到该菌对原油的总降解率为74.14%, 且对直链烷烃、支链烷烃、环烷烃和芳香烃等60种烃类有较高的降解率. 通过特异性基因扩增检测到该菌株基因组中具有4个alkB和1个almA两种烷烃羟化酶基因.     

Combined effects of cadmium and butachlor on soil enzyme activities and microbial community structure

The combined effects of cadmium (Cd, 10 mg/kg of soil) and butachlor (5, 10 and 50 mg/kg of soil) on enzyme activities and microbial community structure were assessed in phaeozem soil. The result showed that phosphatase activities were decreased in soils with Cd (10 mg/kg of soil) alone whereas urease acitivities were unaffected by Cd. Urease and phosphatase activities were significantly reduced by high butachlor concentration (50 mg/kg of soil). When Cd and butachlor concentrations in soils were added at milligram ratio of 2:1 or 1:2, urease and phosphatase activities were decreased, while enzyme activities were greatly improved at the ratio of 1:5. This study indicates that the combined effects of Cd and butachlor on soil urease and phosphatase activities depend largely on the addition concentration ratios to soils. The random amplified polymorphic DNA (RAPD) analysis showed that the changes occurring in RAPD profiles of different treated samples included variation in loss of normal bands and appearance of new bands compared with the control soil. The RAPD fingerprints showed substantial differences between the control and treated soil samples, with apparent changes in the number and size of amplified DNA fragments. The results showed that the addition of high concentration butachlor and the combined applied Cd and butachlor significantly affected the diversity of microbial community. The present results suggest that RAPD analysis in conjunction with other biomarkers such as soil enzyme parameter etc. would prove a powerful ecotoxicological tool.     

Changes in nutritional values induced by butachlor in juvenile diploid and triploid <Emphasis Type="Italic">Clarias gariepinus</Emphasis>

There is a paucity of information about the effects of environmental stressors on nutritional values in fish. This study investigated the effects of the organochlorine pesticide, butachlor, on key indicators of nutritional value in both diploid and triploid African catfish (Clarias gariepinus). Amino acids (AA), fatty acids (FA), and the proximate composition (protein, lipid, moisture, and ash content) in the white muscle of full-sibling juvenile fish were measured following a 21-day exposure to graded butachlor concentrations [mean measured: 26.3, 48.4, and 66.1 µg/L]. No significant differences in AAs, FAs, protein, lipid, moisture, or ash content were observed between unexposed diploid and triploid fish. In diploids, exposure to butachlor significantly altered the concentrations of some of the AAs and FAs, and protein content, when compared to the control group. In triploid fish, however, butachlor treatments had no effect on the AA or proximate composition, but significantly changed the concentration of two individual FAs in the muscle. Butachlor treatments showed fewer changes in the nutritional values of triploid fish. This research is the first to study the nutritional values in any polyploid animals following the exposure to a contaminant.     

Carbon isotope anatomy of a single graphite crystal in a metapelitic migmatite revealed by high-spatial resolution SIMS analysis

High-spatial resolution carbon isotope analyses of natural graphite using secondary ion mass spectrometry (SIMS), together with conventional mass spectrometry techniques, demonstrate isotopic heterogeneity within single graphite crystals precipitated from a partially melted metamorphic rock. SIMS ¹³C/¹²C measurements were calibrated using an internal graphite standard previously analyzed by conventional isotope ratio mass spectrometry, which gave a reproducibility of 0.3‰ (1σ) at a spatial resolution of 2–3 μm. This resolution helped to identify an unusual carbon isotope distribution in a single graphite crystal from a metapelitic leucosome, showing remarkable core to rim variations with sharp δ¹³C steps up to 10‰. The results suggest that the graphite crystal grew from one edge to other forming layers perpendicular to the c-axis. The sharp isotopic steps indicate the presence of disequilibrium carbon isotope zoning in graphite and points to the possible existence of carbon isotope sector zoning. Intra-crystalline carbon isotope disequilibrium in graphite is believed to have resulted from the difference in diffusivity between ¹²C and ¹³C in the growth medium to the interface of graphite precipitation in different growth sectors.     

Lipid analysis of a ground sloth coprolite

Coprolites can provide detailed information about the nutritional habits and digestive processes of the animals that produced them and may also yield information about the palaeoenvironment in which the animal existed. To test the utility of the lipid biomarker approach to coprolite analysis, lipids were extracted from a coprolite of the Pleistocene ground sloth Nothrotheriops shastensis. Gas chromatography/mass spectrometry results revealed a dominant spiroketal sapogenin component identified, using nuclear magnetic resonance spectroscopy, as epismilagenin. The dominance of epismilagenin is probably due to ingestion of Yucca spp. and Agave spp., which is consistent with previous studies on the diet of this species.     

Coagulant proteins identified in Mustard: a potential water treatment agent

The use of natural coagulant protein in drinking water treatment has been discussed for a long time, though the method is still not in practice, probably due to limited knowledge and availability of material. In the present work, different Mustard varieties were tested for the presence of coagulant protein compared with Moringa seed extract and their potential application in water treatment. The coagulation activity of the protein extract was measured using synthetic clay solution as well as water from pond. The protein content was determined by Bradford method, molecular mass determined by Sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and peptide sequence was analyzed by Mass spectrometry. Extract of Mustard (large) and Moringa seed showed coagulation activity of ?70 and ?85 % after 90 min, respectively. Interestingly, seed extracts from other Mustard varieties had coagulation activity after heat activation at 95 °C for 5 h. However, the coagulation activity of Mustard seed extract against turbid pond water was higher (?60 %) compared to Moringa seed extract (?50 %). The peptide sequence analysis of 6.5 and 9 kDa proteins was found to be homologous to Moringa coagulant protein and napin3, respectively. To our knowledge, this could be the first report on Mustard seed having coagulant protein. The coagulation activity of Mustard (large) against highly turbid pond water suggested that it could be a potential natural coagulant for water treatment.     

APDC-MIBK萃取石墨炉原子吸收法测定地质样品中痕量钯

近年来金矿源岩研究引起国内外地质学家的极大关注。贵金属元素把具有双重特性,在超镁铁质岩浆结晶过程中性状与金相近,表现出强烈亲硫的特点,新鲜的没有发生过任何金流失的岩石,二者比值近似为一常数。把在成岩乃至于变质作用过程中呈惰性,保持其原始含量不变而又与金性状完全不同,这种双重性特征有可能借助于常数K=Au(原)/Pd(原),推算出没有发生过任何金流失时的岩石原始金含量(王建安,1986)。即通过样品中把的分析值求得原始金含量,借此对金矿源岩进行研究与判定。     

Biomarker assemblage of some Miocene-aged Bulgarian lignite lithotypes

Two homogeneous (humovitrain and xylain) and one heterogeneous (humoclarain) lithotype macerals, separated from a lignite, were subjected to mild reductive treatment by NaH. The extensive chromatographic separation of the decalin-soluble fraction revealed some structural peculiarities. A strong predominance of α-phyllocladane was characteristic for all macerals. Series of n-, iso-, and anteiso-alkanes, regular isoprenoids, alkylbenzenes and 1-methyl-4-n-alkylcyclohexanes were identified by mass spectrometry. An angiosperm source input was represented by friedelane, lupane and seco-hopane structures. Products of des-A and des-E-ring cleavages and C-10 demethylation were registered by mass spectrometry. The main difference was in the hopane distribution pattern. A strong prevalence of extended ββ-hopanes was found in the humoclarain sample. The mass spectral data revealed the existence of a basic difference in hopane precursors—diploptent or diplopterol for the homogeneous lithotypes and bacteriohopanetetrol for the heterogeneous lithotype.     

节杆菌A3分裂蛋白FtsQ基因克隆及其功能预测

利用TAIL-PCR(Thermal Asymmetric Interlaced PCR)方法克隆节杆菌A3 ftsq基因序列,基于生物信息学软件分别进行ftsq序列同源性分析、蛋白质FtsQ跨膜域及三级结构预测,初步预测该基因所编码蛋白FtsQ的功能.结果表明:节杆菌A3 ftsq基因全序列1035 bp,编码氨基酸344个;节杆菌A3 ftsq基因与谷氨酸棒状杆菌、结核分枝杆菌和天蓝色链霉菌ftsq亲缘关系比较近,与大肠杆菌、枯草芽孢杆菌、新月柄杆菌和肺炎链球菌亲缘关系比较远;节杆菌蛋白质FtsQ为一次跨膜蛋白,包括膜内域(1-114氨基酸残基)、跨膜域(115-139氨基酸残基)和膜外域(140-344氨基酸残基);空间结构预测节杆菌FtsQ膜内域和跨膜域空间结构缺失.因此,节杆菌A3 FtsQ蛋白与大肠杆菌、枯草芽孢杆菌FtsQ膜内域在长度和空间结构存在显著不同,其膜内域较长,较长的膜内域段可能取代了缺失的FtsA的功能,辅助Z环的锚定和下游蛋白的吸附.当节杆菌A3处于电离、辐射、寒冷等极端环境时,ftsq或许是节杆菌生存的必须基因;当节杆菌处于实验条件温度为20℃,营养充足,ftsq则可能是非必须基因.节杆菌A3 FtsQ在细菌细胞分裂时可能通过与上游蛋白、下游蛋白相互作用,确定细胞分裂位点和速度;同时FtsQ参与合成肽聚糖,一方面,促使细胞内陷皱缩,细胞一分为二;另一方面,FtsQ合成厚厚的细胞壁以适应极端环境的需要.     

Uranium and Thorium Concentration and Isotopic Composition in Five Glass (BHVO‐2G,BCR‐2G,NKT‐1G,T1‐G,ATHO‐G) and Two Powder (BHVO‐2, BCR‐2) Reference Materials

Here we report uranium and thorium isotopic ratios and elemental concentrations measured in solid reference materials from the USGS (BHVO‐2G, BCR‐2G, NKT‐1G), as well as those from the MPI‐DING series (T1‐G, ATHO‐G). Specifically created for microanalysis, these naturally‐sourced glasses were fused from rock powders. They cover a range of compositions, elemental concentrations and expected isotopic ratios. The U‐Th isotopic ratios of two powdered source materials (BCR‐2, BHVO‐2) were also characterised. These new measurements via multi‐collector thermal ionisation mass spectrometry and multi‐collector inductively coupled plasma‐mass spectrometry can now be used to assess the relative performance of techniques and facilitate comparison of U‐Th data amongst laboratories in the geoscience community for in situ and bulk analyses.     

Organic compound tracers of fine soil and sand particles during summer in the metropolitan area of Riyadh,Saudi Arabia

Soil and sand fine particles, which may be resuspended as fine dust in the atmosphere, contain a variety of anthropogenic and natural organic components. Samples of fine soil and sand particles (sieved to <125 μM) were collected from the Riyadh area in the summer of 2003 and extracted with a mixture of dichloromethane and methanol (3:1, v:v). The derivatized total extracts were analyzed by gas chromatography–mass spectrometry in order to characterize the composition and sources of the organic components. Both anthropogenic and natural biogenic inputs were the major sources of the organic compounds in these extracts. Discarded plastics and vehicular emission products were the major anthropogenic sources in the fine particles from populated areas of the city. Their tracers were plasticizers, UCM, n-alkanes, hopanes and traces of steranes. Vegetation was the major natural source of organic compounds in samples from outside Riyadh and included n-alkanols, n-alkanoic acids, n-alkanes, methyl alkanoates, sterols and triterpenoids. Carbohydrates had high concentrations (42–54%) in all samples and indicate sources from decomposition of cellulose and/or the presence of viable microbiota such as bacteria and fungi. The results were also compared with the data obtained in winter 2002 and showed that anthropogenic inputs were higher in summer than in winter, whereas the opposite trend was observed for natural inputs.     

Effect of Bacillus mucilaginosus on weathering of phosphorite and a preliminary analysis of bacterial proteins

The authors investigated the effect of Bacillus mucilaginosus on weathering of phosphorite. Analysis of different proteins was of significance in exploring the molecular biological mechanism in the bacterial weathering process. The concrete methods are described as follows： Mineral powder was put into liquid culture medium and B. mucilaginosus was incubated in the medium. The control （group） had no mineral powder in the medium. The treatments and controls were cultured simultaneously under the same condition. In a few days, the supernatant was filtrated, the main cations （Ca^2＋, Mg^2＋, Na^＋, Mn^2＋, Al^3＋, Fe^3＋, K^＋） were measured by ICP-OES, and the contents of water soluble phosphorus （Pws） and silicon （Siws） were determined by colorimetry. The residual solid was weighed on the filter paper, followed by digestion with concentrated HNO3. The concentrations of the main cations and Pws, Siws in the digest liquid were measured by using the method mentioned above. After the supernatant was centrifuged, the precipitation was used to analyze the protein differences between the treatment groups and the control groups by 2-dimentional gel electrophoresis （2-DE）. The experimental results showed that apatite and quartz were partially weathered, but kaolinite was dissolved completely. The population of bacteria increased when mineral powder was added in the liquid medium. Software analysis and comparison of the 2-DE pictures of bacterial proteins revealed 1134 visible protein spots in the treatment group, and 729 visible protein spots in the control group. To compare the bacterial protein expression contents of the treatment group with those of the control group, there were 496 different protein spots, including 214 protein spots which indicated that the protein contents increased, 75 protein spots were indicative of a decrease, and 207 proteins were newly synthesized. It is proposed that the increased bacterial contents may be related to some protein expression and activation after the     

Kerogen of Toarcian shales of the Paris Basin. A study of its maturation by flash pyrolysis techniques

A set of 14 samples—both extracted and unextracted from the Toarcian of the Paris Basin have been investigated using Curie-point pyrolysis-mass spectrometry and Curie-point pyrolysis gas chromatography mass spectrometry. The relative amount of n-alkenes and n-alkanes in the pyrolyzates increases with increasing maximum burial depth of the samples. Comparison of the pyrolysis data of extracted and unextracted samples shows that generation of hydrocarbons from the kerogen starts at a maximum burial depth of ~ 1000m. The increase of pristane and phytane in the extracts of the deeper samples is correlated with the gradual decrease of the characteristic pyrolysis product prist-1-ene. Three samples yield pyrolyzates with high relative amounts of aromatic compounds. This phenomenon probably reflects a different type of contributing organic matter and/or a different environment of sedimentation.     

Organic tracers in sediments from the coastal zone of Ras Abu el-Darag,Gulf of Suez

Sediment samples from the coastal zone of the Gulf of Suez contain a variety of organic compounds from anthropogenic and natural sources. A total of 12 surface samples of bottom sediments were collected with an Ekman grab sampler along an off-shore transect south of Ras Abu el-Darag. The samples were extracted with a mixture of dichloromethane and methanol (3:1 v/v) after drying and sieving through 250 μm mesh. The extracts were derivatized and analyzed by gas chromatography–mass spectrometry in order to characterize the chemical composition and sources of the organic components. Marine with minor terrestrial biota were the major natural sources of organic tracers and included n-alkanoic acids, sterols and saccharides (5.7–76.7%). Anthropogenic sources, from petroleum related activities, detergent usage for spill cleaning and littering, are indicated by the presence of n-alkanes with carbon preference index ≤1.0, hopanes, steranes, unresolved complex mixture of branched and cyclic hydrocarbons, alkyl nitriles, alkamides and plasticizers. Their total relative concentrations ranged from 23.3 to 97.3% of the total extracts. Petroleum residues from natural seepage may also be part of these hydrocarbons. The levels of anthropogenic inputs decrease from about 94% in coastal zone sediments to about 20% in sediments from the reef front.     

An experimental study of magnesium-isotope fractionation in chlorophyll-a photosynthesis

Measurements are presented of the magnesium isotopic composition of chlorophyll-a, extracted from cyanobacteria, relative to the isotopic composition of the culture medium in which the cyanobacteria were grown. Yields of 50-93% chlorophyll-a were achieved from the pigment extracts of Synechococcus elongatus, a unicellular cyanobacteria. This material was then digested using concentrated nitric acid to extract magnesium. Separation was accomplished using columns of cation-exchange resin, which achieved a 103 ± 10% yield of magnesium from chlorophyll-a. This procedure ensured accurate measurement of the magnesium-isotopic ratios without isobaric interferences using a multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). We find a slight depletion in the heavier isotopes of magnesium in chlorophyll-a relative to culture medium, early growth phase: Δ²⁶Mg = −0.71(±0.35)‰ and Δ²⁵Mg = −0.37(±0.18)‰; late growth phase: Δ²⁶Mg = −0.53(±0.20)‰ and Δ²⁵Mg = −0.26(±0.11)‰, due to an apparent mass-dependent fractionation. We suggest that the small fractionation results from chelation during intracellular processes. A likely candidate for this chelation step involves the magnesium-chelatase enzyme, which mediates the insertion of magnesium to the tetrapyrrole ring during chlorophyll-a biosynthesis. Proof of this hypothesis can be tested with biological controls whereby steps in the enzymatic pathways of chlorophyll synthesis are selectively suppressed.     

中低应变率下的岩石损伤本构模型研究

深部岩石的破碎与钻探中,岩石主要处在中低应变率的载荷作用下,而目前的研究还沿用中高应变率推导的动态损伤本构关系。从工程背景和试验角度分析了中低应变率下的岩石动力学特性,提出Maxwell体、Bingham体和损伤体的并联模型,借助拉普拉斯变换,引入基于岩石孔隙、裂隙劣化的损伤变量,导出了中低应变率下的岩石动态损伤本构模型。利用该模型对泥质砂岩和花岗岩在应变率为87 s-1、382 s-1、673 s-1时的应力-应变试验数据进行拟合,并将拟合结果与实测数值、原文献拟合曲线对比,结果表明该理论模型适用性较好。分析拟合参数可知,该动态损伤本构模型能够主动适应中低应变率两类情况,本构曲线和损伤变量的变化符合实际情况。     

Levels and distributions of organic source tracers in air and roadside dust particles of Kuala Lumpur,Malaysia

The concentrations of n-alkanes, unresolved complex mixture (UCM), petroleum molecular markers, other tracers of cooking and burning emissions, and natural background in atmospheric particles and roadside dust particles were measured at eight locations in the city center and the suburbs of Kuala Lumpur, Malaysia. Atmospheric particles were collected using high-volume filtration (PM-10, GFF) over 24 h average periods. Road dusts were swept up, dried and sieved. Both types of samples were extracted with dichloromethane/methanol mixture (3:1 v/v) by ultrasonic agitation. The extracts were then fractionated by column chromatography and the alkanes subjected to gas chromatography–mass spectrometry (GC–MS). Total extracts were also analyzed directly by GC–MS after silylation. The molecular distributions of compounds as well as diagnostic geochemical ratios were determined in order to identify the sources of the organic compounds. Samples collected from a rural area and lubricating oils were also analyzed for comparisons. Anthropogenic and biogenic sources such as vehicular emissions, waxes of higher plants, food cooking operations, and biomass and domestic refuse burning processes contributed to the organic matter content of atmospheric and to lesser extent, roadside dust particles.     

青藏高原土壤中链霉菌的分离鉴定及其抗菌活性研究

对从青藏高原采集的土壤样品中的链霉菌进行了分离鉴定,并对其抗菌活性进行了研究. 结果表明：11份土样中分离出菌落形态特征明显不同的链霉菌相似菌株151株,对其中43株进行了16S rDNA测序分析,41株菌株与已知链霉菌的相似性在99%以上,确定为链霉菌属（Streptomyces）菌种,而菌株WDL-DM-5和TTH-DM-1与已知链霉菌的序列相似性分别为90.76%和95%. 抗菌试验表明,68株链霉菌对革兰氏阳性菌和阴性菌有抗性,其中41株菌对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌都有明显拮抗性,表明青藏高原土壤中存在强拮抗性的链霉菌.     

Variations in the distributions of sedimentary alkyl porphyrins in the Mulhouse basin in response to changing environmental conditions

Alkyl porphyrins from five sediment layers deposited under different palaeoenvironmental conditions in the Mulhouse basin (Alsace, France) have been examined by normal-phase high performance liquid chromatography and liquid chromatography–tandem mass spectrometry. The fossil pigments show marked differences in distribution among the different lithological zones, with around 40 major alkyl porphyrin components detected. Assignment of structures to a number of the porphyrins has been achieved through detailed studies involving analysis of successive losses experienced during multistage tandem mass spectrometry. A suite of bacteriochlorophyll-derived alkyl porphyrins has been detected that exhibits fragmentations in tandem mass spectrometry not consistent with the presence of either n-Pr or i-Bu moieties. Instead, these unusual geoporphyrins may be evidence of previously undetected neo-Pent substituted alkyl porphyrins. The distributions in the different horizons of the Mulhouse basin core reveal that the relative abundances of certain alkyl porphyrins respond to changes in environmental conditions, reflecting variations in the primary producer community during the deposition of the core.