Fatty Acid and Aliphatic Hydrocarbon Composition of Sarcina lutea Grown in Three Different Media

Sarcina lutea was grown in Trypticase Soy Broth, Nutrient Broth, and a chemically defined medium. Gas chromatographic analysis of lipid components demonstrated that the composition of the medium had an effect on the relative per cent composition of the aliphatic hydrocarbons and fatty acids present in the cells. The branched olefinic hydrocarbons from the organisms grown in Trypticase Soy Broth showed no predominance or only a slight predominance of odd-numbered carbon chains, whereas the hydrocarbons from cells grown in the other two media showed an obvious predominance of odd-numbered carbon chains. The monocarboxylic fatty acid content and distribution showed only minor differences, with all normal saturated fatty acids present in relatively small quantities for cells grown in Nutrient Broth and in a chemically defined medium.     

Changes in Prokaryote and Eukaryote Assemblages Along a Gradient of Hydrocarbon Contamination in Groundwater

Groundwater biota are particularly sensitive to environmental perturbations such as groundwater contamination. The diversity of prokaryotic and eukaryotic biota has been examined along a gradient of chlorinated hydrocarbon (CHC) contamination in the Botany Sands, an urban coastal sand-bed aquifer (Sydney, Australia). Molecular techniques were used to analyze the richness and composition of prokaryote and eukaryote assemblages using 16S and 18S rDNA, respectively. Taxon richness did not change significantly along the gradient for either prokaryotes or eukaryotes; however, significant shifts in assemblage composition were evident for both groups. Assemblage changes were most strongly correlated with concentrations of the major CHC, cis-1,2-dichloroethene, but the concentrations of a number of the contaminants were also correlated, making it difficult to infer if effects were due to any particular contaminant. The presence of cis-1,2-dichloroethene and other secondary ethenes suggests in situ breakdown of the primary CHCs via natural attenuation. The current focus of management of the Botany aquifer is to stop the contaminant plume reaching the adjoining estuary. This approach is clearly justified given the changes evident in the microbial assemblages in the groundwater, which are a likely consequence of the contamination.     

Sucrose Lipids of Arthrobacteria,Corynebacteria and Nocardia Grown on Sucrose

Arthrobacter paraffineus KY 4303, when grown on sucrose as the sole carbon source, produced novel glycolipids, either of which was different from trehalose lipid produced from n-alkane by the same microorganism. Two kinds of glycolipids were isolated by chromatography on silicic acid columns. Major components of these lipids were sucrose and α-branched β-hydroxy fatty acid. One of the lipid (SL–1, having high polarity) was identified as 6-O-monofattyacyl glucosly-β-fructoside. Another (SL–2, having low polarity) was partly characterized as sucrose ester of at least two moles of the fatty acid.

Formation of sucrose lipids was also demonstrated in sucrose-grown cells of several microorganisms of Corynebacteria, Nocardia and Brevibacteria, which were isolated as hydrocarbon-utilizing bacteria and could produce a considerable amount of trehalose lipid from n-alkane.     

Hydrocarbon accumulation in freshwater sediments of an urban catchment

The top and bottom of two sediment cores collected from an urban receiving basin in NW London, and stormwater samples from the attendant catchment, have been analysed for their hydrocarbon content. In surface sediments, basal sediments and stormwater, total aliphatic hydrocarbon levels are 445–690 μg g⁻¹ dry wt., 43–224 μg g⁻¹ and 0.36–1.10 mg l⁻¹, respectively; and total levels of polyaromatic hydrocarbons (PAHs) are 780–1 100 μg g⁻¹, 310–640 μg g¹ and 5.83–18.21 mg l⁻¹, respectively. Biodegradation of aliphatics is assessed by phytane:n-C₁₈ and pristane: n-C₁₇ ratios. Hydrocarbon sources are determined from phytane: pristane ratios, odd: even carbon chain length ratios, the presence of an unresolved complex mixture, and by comparison of the amount of methyl-substituted PAH s with that of the parent compounds. Comparison of total levels between surface and basal sediments shows a 1 to 3 fold increase in total PAHs and a 3 to 10 fold increase in aliphatic hydrocarbons over a 120 year period.     

卤代芳烃类化合物的早期妊娠毒性动物模型检测方法的建立

目的建立一套动物模型检测方案,用于筛选和研究对人类和动物早期妊娠有影响的环境卤代芳烃类污染物。方法利用TCDD作为初始研究标准化合物,以NIH小鼠建立动物早期妊娠模型评估方案,包括剂量-反应评估(DRE)、着床前后毒性比较(PPP)、子宫蜕膜细胞反应(DCR)和胚胎转移速率(ETR)分析。结果DRE发现TCDD剂量依赖性地引起了第9天胚胎数量的显著减少。PPP比较发现100 ng/(kg.d)对胚胎着床前期影响显著大于着床后期;胚胎重量评估发现,TCDD在妊娠早期的不同时间给药均影响了胚胎的发育,造成发育迟缓,重量减轻。DCR检测发现TCDD处理显著抑制(P<0.01)假孕小鼠子宫蜕膜。ETR分析发现TCDD未影响胚胎在输卵管中的转移速度,但造成分裂卵发育迟缓,着床前分裂卵丢失(P<0.05)。对出生前胚胎成活率观察发现,TCDD可造成出生前胎儿死亡,胎儿成活率低于妊娠中期的胚胎成活率。结论TCDD对着床前胚胎的毒性明显大于着床后,并具有持续毒性的特点。其机理涉及抑制子宫蜕膜细胞反应、造成着床前分裂卵的丢失或发育的不同步。     

Prediction of Petroleum Hydrocarbon Bioavailability in Contaminated Soils and Sediments

Recently, several laboratory methods have been developed for the prediction of contaminant bioavailability. So far, none of these methods has been extensively tested for petroleum hydrocarbons. In the present study we investigated solid-phase extraction and persulfate oxidation for the prediction of total petroleum hydrocarbon (TPH) bioavailability. One sediment and two soil samples were subjected to solid-phase extraction, persulfate oxidation, and biodegradation, after which hydrocarbon removal was compared. It was demonstrated that a short solid-phase extraction (168?h) provided a good method for the prediction of the extent of TPH degradation in an optimized slurry reactor (84?d). Solid-phase extraction slightly underestimated the degradation of readily biodegradable hydrocarbons, whereas it slightly overestimated the degradation of poorly biodegradable hydrocarbons. Persulfate oxidation appeared to be unfit for the prediction of TPH bioavailability as persulfate was unable to oxidize hydrocarbons with a high ionization potential. Hydrocarbons that were affected were likely to be transformed rather than completely oxidized. Nevertheless, persulfate oxidation provided a good method for the prediction of polycyclic aromatic hydrocarbon (PAH) bioavailability.     

Physiological Properties of Yeast Cells Grown in the Proteolipid-Supplemented Media

Koji mold proteolipid (PL), a high concentration alcohol-producing factor, promoted yeast growth, and also affected the physiological properties of yeast cells: in the conditions of statical cultures, the cells grown anaerobically in PL-supplemented media showed the highest fermentative activity and the highest alcohol-durability by the dipping method in 20% alcohol for 48 hr, at 20°C, that was similar to moromi (main mash) yeasts in Japanese sake brewing; the cells grown in the stationary culture (with cotton plug) supplemented with PL showed the lowest fermentative activity and relatively low alcohol-durability, similar to moto (seed mash) yeasts; the cells grown anaerobically in PL-unsupplemented media showed high fermentative activity but the lowest alcohol-durability.     

Cell Structure of Yeasts Grown Anaerobically in Aspergillus orpzae-Proteolipid-supplemented Media

Effects of Aspergillus oryzae-proteolipid (PL) on the formation of high concentrations of alcohol, more than 20% as in sake brewing, have been studied. Electron microscopy revealed that there were no vacuoles but many lipid deposits in cytoplasm of the alcoholtolerant cells of Saccharomyces sake Kyokai No. 7, which were obtained by the anaerobic culture supplemented with PL. Sphaeroplasts from the alcohol-tolerant cells were stable in 20% alcohol, whereas those from the untolerant cells grown anaerobically in the PL-unsupplemented media were ruptured. The cell membrane became alcohol-endurable in the anaerobic cultures with PL. Synthetic phospholipid promoted yeast growth and the fermentative activity, whereas a small amount of sterol ester enhanced the alcohoi-endurability. The supplementation of both lipids anaerobically induced physiological properties characteristic of the alcohol-tolerant cells.     

Variation in Petroleum Hydrocarbon Chain Lengths with Depth at a Former Crude Oil and Natural Gas ProductionFacility

An investigation was performed at a former crude oil and natural gas production facility to evaluate whether releases from the product flowlines, gathering lines or water injection lines had impacted soil beneath the site. Thirty-six trenches were initially excavated and sampled beneath the former piping runs to a maximum depth of 6?m. After the trenching investigation, nine soil boreholes were advanced and sampled to a depth of approximately 18?m to further delineate the lateral and vertical extent of impacted soil. Soil samples collected from the trenches and boreholes were analyzed for total petroleum hydrocarbons (TPH) in accordance with ASTM Method 2887. The results of the investigation indicated that TPH impacted soil was present within several areas of the 40-ha site. The petroleum hydrocarbons generally had chain lengths ranging from C₆ to C₃₅, characteristic of light crude oil. The impacted soil also contained condensate, the volatile portion of crude oil. Condensate consists of short-chain hydrocarbons (C₁ to C₁₂) and is characterized by low levels of aromatic volatile organic compounds (VOCs). The condensate typically was more prevalent at depths below 4.5?m than the less volatile, longer chain length hydrocarbons. Statistical analysis of TPH data collected during subsequent excavation activities showed that the mean percentage of condensate was significantly greater at depths below 4.5?m than in shallower samples. In contrast, the mean percentage of TPH compounds in the diesel range (C₁₄ to C₂₃) was significantly greater in samples collected at depths above 4.5?m. The difference in the mean percentage of heavier hydrocarbons (C₂₄ to C₄₄+) with depth was not statistically significant.     

Population Dynamics of Meloidogyne incognita on Corn Grown in Soil in Fested with Arthrobotrys conoides

Microplot and greenhouse experiments were conducted to evaluate the effects of soil incorporation of the nematophagous fungus Arthrobotrys conoides and green alfalfa mulch on the population dynamics of Meloidogyne incognita on corn. Reproduction of M. incognita and the incidence of root galling were reduced by the addition of A. conoides and/or green alfalfa in all tests. Numbers of juveniles were reduced by as much as 84%, and eggs were fewest in early to mid-season soil samples from microplots. Yields increased in treatments with A. conoides and/or green alfalfa in greenhouse tests and in the microplot tests in 1979. No interaction was found between the fungus and green alfalfa in the reduction of the nematode population.     

Flash pyrolysis of the outer cortical tissues in Lower Devonian Psilophyton dawsonii

Coalified residues of the xylem and peripheral structure tissues (stereomc) from perminei alized (CaCO₃) Lower Devonian Psilophyton dawsomi have been analysed by Hash pyrolysis-gas chromatography-mass spectrometry. Both yielded C₁-C₃ alkylphenols, C₁-C₃ alkylbenzenes, C₁-C₃ alkylnaphthalenes, although with varying relative abundances. The stereomc also generated a scries of n -alk-1-cries and H-alkanes (C₃C₂₄, maximum at C₁₀) which is believed to be derived from the cuticle. The sources of the aromatic compounds are discussed, and while it is concluded that those in the xylem are derived from lignin, the macromolecule having been degraded by diagencsis and thermal maturation, the molecular sources of those from the stereomc may also include a wide range of substances including simple phenolic acids, flavonoids and non-lignin polyphenolics. Possible functions for the stereome are discussed.     

A Case of Phosphorus Limiting Monoaromatic Hydrocarbon Biodegradation in Groundwater

A funnel-and-gate system has been installed at a natural gas condensate-contaminated field site, for aerobic treatment of contaminated groundwater. Laboratory microcosms were used to assess the ability of indigenous microorganisms to biodegrade monoaromatic hydrocarbons (benzene, toluene, ethylbenzene and isomers of xylene and trimethylbenzene) in the groundwater. Biodegradation was restricted unless phosphorus was added to the site water. Inorganic nitrogen addition had little effect. Estimated zero-order biodegradation rates for benzene, the predominant monoaromatic hydrocarbon in the water, were 87 μj,g/L/d in the absence of added P, but as high as 397 μg/L/d in P-amended microcosms. It was found that finely ground apatite rock could be used as a source of P by the groundwater microbiota, suggesting that this material could serve as a long-term P source in the funnel-and-gate treatment system.     

Identification and characterization of a strain-dependent cystathionine β/γ-lyase in Lactobacillus casei potentially involved in cysteine biosynthesis

The trans -sulfuration pathways allow the interconversion of cysteine and methionine with the intermediary formation of cystathionine and homocysteine. The genome database of Lactobacillus casei ATCC 334 provides evidence that this species cannot synthesize cysteine from methionine via the trans -sulfuration pathway. However, several L. casei strains use methionine as the sole sulfur source, which implies that these strains can convert methionine to cysteine. Cystathionine synthases and lyases play a crucial role in the trans -sulfuration pathway. By applying proteomic techniques, we have identified a protein in cell-free extracts of L. casei , which showed high homology to a gene product encoded in the genome of Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus and Lactobacillus helveticus but not in the genome of L. casei ATCC 334. The presence of the gene was only found in strains able to grow on methionine as the sole sulfur source. Moreover, two gene variants were identified. Both gene variants were cloned and expressed heterologously in Escherichia coli . The recombinant enzymes exhibited cystathionine lyase activity in vitro and also cleaved cysteine, homocysteine and methionine releasing volatile sulfur compounds.     

Production of Bacillus thuringiensis Berliner var. kurstaki Grown in Alternative Media

Agro - industrial residues and by - products available in southeastern Brazil were used as ingredients for low - cost culture media for liquid fermentation of Bacillus thuringiensis var. kurstaki. Highest spore yield was obtained with a medium containing cheese whey , soya bean milk and molasses (WSM) . Crystals and spores were produced in all media and potency of the final product was highest for nutrient broth + yeast extract medium (NBY) . There was no correlation between the number of spores in the fermented media and the potency of the preparations . Considering all three factors , the potencies , costs and yields of the final products , lowest relative cost was obtained with BMM medium ( Bombyx mori pupae + molasses) . NBY and WSM had intermediate relative cost approximately nine times higher than BMM . The cost analysis suggests that BMM medium should be preferred for local production of B. thuringiensis var . kurstaki in comparison to other media tested . The results also demonstrate the importance of considering yields , cost and potency of the B. thuringiensis preparations in selecting the production medium .     

Importance of Different Volatile Petroleum Hydrocarbon Fractions in Human Health Risk Assessment

Soil vapor data for benzene and four aliphatic and aromatic hydrocarbon fractions from five volatile petroleum hydrocarbon (VPH)-contaminated sites in western Canada were used together with the Canadian Council of Ministers of the Environment (CCME) Canada-Wide Standard for petroleum hydrocarbons to investigate the relative importance of benzene and the different fractions in human health risk assessment. VPH concentrations in soil vapor samples ranged from 4.0 to 4200?mg/m³, of which 0 to 4.6% was BTEX and 90 to 95% was hydrocarbons of the C_5–8 aliphatic fraction. VPH inhalation exposure by an adult receptor in a hypothetical, commercial building was modelled deterministically assuming 16- and 70 year occupational tenures. The magnitude of hazard quotients varied widely between sites, but their hydrocarbon fraction signatures were consistent, and characterized by higher hazard quotients in the C_5–8 and C_9–10 aliphatic and C_9–10 aromatic fractions relative to benzene and the TEX aromatic fraction. This work has shown that the C_5– and C_9–10 aliphatic fractions yield greater relative risk than the commonlyregulated TEX compounds, and that benzene becomes the primary chemical of potential concern only when an occupational tenure approaching 70 years is assumed.     

硫灯和氙灯下生长的黄瓜幼苗植物激素水平的差异

就人工气候室两种光源硫灯和氙灯引起黄瓜幼苗生长差异的原因进行了初步探讨.与生长在氙灯下的幼苗相比,硫灯下生长的幼苗较矮.组织细胞观察显示,硫灯下生长的黄瓜幼苗中胚轴表皮和皮层细胞纵向单位毫米长度所含细胞数目比氙灯下多.内源激素分析结果表明,硫灯下生长的黄瓜幼苗内源激素吲哚乙酸(IAA)和赤霉素(GA3)含量较氙灯下分别低17%和24%,而脱落酸(ABA)含量高31%.推测硫灯和氙灯下黄瓜幼苗生长的差异可能与内源激素调控有关.     

Phialophora graminicola, a dark septate fungus, is a beneficial associate of the grass Vulpia ciliata ssp. ambigua

The influence of three organic compounds and bakers' dry yeast on growth of external mycelium and phosphorus uptake of the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith (BEG 87) was examined. Two experiments were carried out in compartmentalized growth systems with root-free sand or soil compartments. The sand and soil in the root-free compartments were left untreated or uniformly mixed with one of the following substrates (0.5 mg g⁻¹ soil): bakers' dry yeast, bovine serum albumin, starch or cellulose. Effects of the organic substrates on biomass and hyphal length density of the arbuscular mycorrhizal fungus were examined by using specific fatty acid signatures in combination with direct microscopy. Micro-organisms other than the arbuscular mycorrhizal fungus were measured by fatty acid signatures, and radioactive ³³P labelling of the root-free soil was used to determine arbuscular mycorrhizal hyphal phosphorus uptake. In general, hyphal growth of G. intraradices was enhanced by yeast and bovine serum albumin, whereas the carbon sources, starch and cellulose, depressed fungal growth. By analysing the fatty acid 16:1ω5 from phospholipids (indicating mycelium) and neutral lipids (indicating storage structures) it was shown that increased fungal growth due to yeast was mainly in vegetative hyphae and less in storage structures. Arbuscular mycorrhizal hyphal phosphorus uptake was decreased by cellulose, but unaffected by the other substrates compared with the control. This means that both growth and phosphorus transport by the arbuscular mycorrhizal fungus were decreased under cellulose treatment. However, the composition of the microbial community varied under different substrate conditions indicating a possible interactive component with arbuscular mycorrhizal hyphal growth and phosphorus uptake.