Effects of heat treatment on oil-binding ability of rice flour

Heat-treated (120 °C for 120 min) rice flour showed high affinity to oil (oil-binding ability). This oil-binding ability could be observed by shaking the heat-treated rice flour (2.0 g), oil (4.0 mL), and water (20 mL) vigorously in a test tube, and the oil bound to the rice flour sank into the water. To examine the time-dependent levels of the oil-binding ability, rice flour was heat-treated at 120 °C for 10, 20, 40, 60, and 120 min, and the precipitated volume of oil/rice flour complex increased with an increase of the heating time. The oil-binding ability of the rice flour was not affected by the treatments with diethyl ether or boiled chloroform/methanol (2:1) solutions, which suggested no relationship to the oil in the rice flour, but was lost upon alkali (0.2% NaOH solution) or pepsin treatment, which suggested its relationship to the rice proteins.     

Attachment and germination of Entomophaga maimaiga conidia on host and non-host larval cuticle

The lepidopteran-specific fungal pathogen Entomophaga maimaiga is highly virulent against Lymantria dispar (gypsy moth) larvae, and other members of the family Lymantriidae. Numerous species in the subfamily Cuculliinae (Family Noctuidae) are not susceptible to E. maimaiga due to the inability of this fungus to penetrate the larval cuticle. Conidial attachment and germination were compared among five cuculliine species and L. dispar using bioassays and scanning electron microscopy. Although conidia were showered evenly across larvae during bioassays, on L. dispar conidia were most abundant on segments, where they adhered well to the cuticle and germinated at high percentages. Conidia on cuculliine cuticles were predominantly found in large, loose aggregations in intersegmental areas. Few conidia on cuculliine cuticle germinated and scanning electron microscopy revealed a thick film of mucous enveloping conidia. We hypothesize that the conidia on cuculliines become coated by this film and were only loosely attached to the larval cuticle. No such film was seen on L. dispar larvae where individual conidia appeared well attached. On L. dispar larvae many conidia also adhered to setae. To determine if hydrophobicity affected the ability of E. maimaiga conidia to attach and germinate on a substrate, a goniometer was used to determine relative hydrophobicity of larval cuticles. L. dispar cuticle was more hydrophobic than cuculliine cuticle, suggesting that a high level of hydrophobicity could be a required characteristic for hosts. Cuticles from four cuculliine species and L. dispar were sequentially extracted using hexane, chloroform, and methanol. Conidia were showered onto glass slides coated with the different extracts and germination was quantified. Methanol extracts of cuculliine cuticle consistently decreased germination, compared to all extracts of L. dispar cuticle. For all L. dispar extracts, the majority of conidia produced germ tubes, which is a normal prerequisite for cuticular penetration. For the cuculliines, conidia exposed to hexane and chloroform extracts produced secondary conidia as did all controls, but the conidia exposed to cuculliine methanol extracts that germinated produced germ tubes. These studies demonstrated that a range of factors act in concert to prevent E. maimaiga infection of the cuculliine species investigated.     

一株耐盐葡萄球菌的分离鉴定及其特性分析

本文旨在分离筛选出在高盐环境中具有潜在应用可能性的菌株。在筛选耐盐酵母的过程中分离出一株耐盐菌株,采用形态特征观察、生理生化实验和16S rDNA基因测序进行菌株鉴定,鉴定结果显示该菌为沃氏葡萄球菌(Staphylooccus warneri),命名为SW-1。进一步对其药敏特性、耐盐性和表面疏水性进行检测,结果表明,该菌株对大部分抗生素极敏感,在含20%(质量分数)NaCl的LB培养基中仍能良好生长,对氯仿、乙酸乙酯和正丁醇的疏水率依次为43%、34%和39%。沃氏葡萄球菌SW-1在高盐条件下能快速适应环境积累生物量,具有优良的生物学特性,为开发和利用耐盐菌株提供参考。     

Physicochemical properties of Shiga toxigenic Escherichia coli

AIMS: To investigate the physicochemical surface properties, such as cellular surface charge, hydrophobicity and electron donor/acceptor potential of a selection of Shiga toxigenic Escherichia coli (STEC) isolates grown in broth and agar culture. METHODS AND RESULTS: Cellular surface charge was determined using zeta potential measurements. Hydrophobicity of the isolates was determined using bacterial adhesion to hydrocarbons assay, hydrophobic interaction chromatography and contact angle measurements. Microbial adhesion to solvents was used to determine the electron donor/acceptor characteristics. No differences of surface charge measurements were found between broth and agar grown cultures. Isolates belonging to serogroup O157 and serotypes O26:H11 and O111:H- were significantly (P < 0.05) less negatively charged than other STEC serotypes tested. All strains were hydrophilic with most methods and demonstrated a lower hydrophobicity in agar culture compared with broth culture. All strains demonstrated a strong microbial adhesion to chloroform indicating that STEC possess an electron donor and basic character. A relationship between serogroup O157 and other STEC serotypes was apparent using principal-component analysis (PCA). CONCLUSIONS: Combining the results for physicochemical properties using PCA differentiated between strains belonging to the O157 serogroup and other STEC/non-STEC strains. PCA found similar results for broth and agar grown cultures. SIGNIFICANCE AND IMPACT OF THE STUDY: Particular serotypes of STEC possess similar physicochemical properties which may play a role in their pathogenicity or potential attachment to various surfaces.     

The mineralization of chloroform in river sediments

The formation of¹⁴CO₂ from 3 μg l⁻¹ labelled chloroform was studied in anaerobic Dutch river sediments. All incubations were performed under anaerobic conditions. The observed first order mineralization kinetics showed half-lives of 2–37 days at 20°C in 12 muddy sediments. In contrast most of the sandy sediment samples did not show a mineralization of chloroform. Most probable number analysis revealed about 3.10⁴ chloroform mineralizing bacteria per g of dry sediment in a muddy sediment and 1–2.10³ chloroform mineralizing bacteria per g of dry sediment in a sandy sediment. Therefore the persistence of chloroform in sandy sediments is not caused by the absence of chloroform mineralizing bacteria but by the inactivity of these bacteria. This inactivity of the sandy sediments might allow chloroform from infiltrating river water to reach the groundwater. Mud samples from a relatively unpolluted site showed a similar chloroform mineralization rate compared with the polluted sediments from the rivers Rhine and Meuse. The data indicate that the reductive dechlorination of aliphatic compounds is not influenced at the polluted sites.     

Biotransformation of chloroform by rat and human liver microsomes; in vitro effect on some enzyme activities and mechanism of irreversible binding to macromolecules.

The effects of chloroform on some rat microsomal enzyme activities were studied in vitro. Maximum inhibition of oxygen consumption, NADPH oxidase and NADPH-cytochrome c reductase was observed at 0.5 mM chloroform; prior metabolization of CHCl3 by microsomal monooxygenases increased inhibition by about 50% at 0.2-0.5 mM chloroform. Higher concentrations produced a paradoxical reversal of inhibition, whereas p-nitroanisole demethylase was steadily inhibited by about 50% up to 10 mM chloroform. Irreversible binding of 14CHCl3 was confirmed to depend on chloroform metabolization by monooxygenases. The increased irreversible binding due to phenobarbital induction is accompanied by a diminished affinity towards chloroform as shown by increased KM of irreversible binding, and a higher spectral dissociation constant KS. Aminoacids with nucleophilic functions (histidine, cysteine) partially prevented the irreversible binding of chloroform metabolites to microsomes; non-volatile radioactive derivatives were recovered in trichloracetic acid supernatants when microsomes were incubated with cysteine, but not with histidine. Phosgene has been demonstrated as a biological metabolite of chloroform: its possible reactions with nucleophilic groups of macromolecules, water and added aminoacids partly explain these experimental data. Similar results were obtained with human microsomes, showing that chloroform hepatotoxicity in man could involve the same mechanisms.     

Spatial variation in natural formation of chloroform in the soils of four coniferous forests

Natural chloroform in soil gas below four coniferous forest sites was studied. High concentrations were found within narrow areas??Hot Spots??varying from ~25 to >400 m² in size, with chloroform concentrations being typically 20?C100 times those in corresponding Low Spots.Attempts to localize Hot Spots by visual inspection with regard to type and density of vegetation failed. Possible differences between Hot and Low Spots could be emission, leaching or degradation of chloroform. However, emissions of chloroform from Hot Spots were ~10 times higher than from Low Spots and similarly the chloroform concentration in groundwater below a Hot Spot was ~10 times higher than below the corresponding Low Spot. No differences in chloroform mineralization rates were observed between sites and incubation of soil cores confirmed a larger net formation of chloroform in the Hot Spots. Various soil parameters were measured in order to compare the soil sampled from Hot and Low Spots. The halogenation degree of organic soil samples was in the same range, although slightly higher in the H-horizon of the Hot Spot. The chloroform formation potential of the soil organic matter showed differences between soil horizons but not between sites. The high levels of chloroform in the Hot Spots are probably best explained by differences in chloroform forming activity caused by an uneven distribution of yet unidentified microorganisms, since differences in soil organic matter quality and in emission, leaching and degradation of chloroform as well as a number of additional soil parameters could be completely ruled out.     

Chloroform degradation by butane-grown cells of Rhodococcus aetherovorans BCP1

The ability of a Rhodococcus aetherovorans strain, BCP1, to grow on butane and to degrade chloroform in the 0–633 μM range (0–75.5 mg l⁻¹) via aerobic cometabolism was investigated by means of resting-cell assays. BCP1 degraded chloroform with a complete mineralization of the organic Cl. The resulting butane and chloroform maximum specific degradation rates were equal to 118 and 22 μmol , respectively. Butane inhibition on chloroform degradation was satisfactorily interpreted by means of a model of competitive inhibition, with an inhibition constant equal to 38 % of the estimated butane half-saturation constant, whereas chloroform (at 11 μM) did not inhibit butane utilization. Acetylene (1,720 μM) induced an almost complete inactivation of the degradation of both butane and chloroform, indicating that the studied cometabolic process is mediated by a monooxygenase enzyme. BCP1 proved capable of degrading vinyl chloride and 1,1,2-trichloroethane, but not 1,2-trans-dichloroethylene. BCP1 could grow on the intermediates of the most common butane metabolic pathways and on the aliphatic hydrocarbons from ethane to n-heptane. After growth on n-hexane, it was able to deplete chloroform (13 μM) with a degradation rate higher than that obtained, at the same chloroform concentration, after growth on butane.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Hydrophobic Properties of tRNA with Varied Conformations Evaluated by an Aqueous Two-Phase System

The surface properties of transfer RNA (tRNA) were analyzed using a poly(ethylene glycol)/dextran aqueous two-phase system (ATPS), where the surface net hydrophobicity (HFS) and the local hydrophobicity (LH) were evaluated based on the partition coefficient of tRNA in the ATPS. According to the evaluated HFS values, the surface of the tRNA molecule was hydrophilic at 20° -40 °C, and it became hydrophobic at 50° -80 °C because of the exposure of the intrinsic nucleobases of tRNA. In contrast, the LH values were found to be maximal at 20° -40 °C. The conformation of tRNA was investigated by Raman and circular dichroism (CD) spectroscopies, corroborating the results with the calculated prediction of its secondary structure (Mfold). It was shown that 66% of A-form structure existed at room temperature; the base stacking (θ₂₆₅) was gradually decreased, and the A-form structure (θ₂₀₈) was denatured along with a sigmoid curve against the temperature increase; the denatured secondary structures were observed above 50° C by Mfold prediction. The HFS value of the DNA duplex was found to be hydrophilic, compared to that of the single-stranded DNA, indicating that the exposure of nucleobases is a key factor of the hydrophobic properties of nucleotides. We conclude that the hydrophobic property of the tRNA surface was directly affected by its conformational transition.     

Dechlorination of Chloroform by Methanosarcina Strains

Dehalogenation of carbon tetrachloride, chloroform, and bromoform in pure cultures of Methanosarcina sp. strain DCM and Methanosarcina mazei S6 was demonstrated. The initial dechlorination product of chloroform was methylene chloride (dichloromethane), which accumulated transiently to about 70% of the added chloroform; trace amounts of chloromethane were also detected. The amount of chloroform dechlorinated per mole of methane produced was approximately 10 times greater than the ratio observed previously for tetrachloroethene dechlorination by these strains. The production of ¹⁴CO₂ from [¹⁴C]chloroform and the absence of ¹⁴CH₄ imply that processes in addition to reductive dechlorination operate.     

A rapid determination of sodium dodecyl sulfate with methylene blue.

A rapid procedure of sodium dodecyl sulfate determination was established. The method is sensitive (0–6 μg of SDS), accurate, easy to operate and uninfluenced by the presence of protein. The method is a modification of Mukerjee's that takes advantage of water-insoluble salt formation between the detergent and methylene blue, which was extracted by chloroform. Absorbance was measured in a test-tube-push-in type spectrophotometer (Bausch and Lomb Spectronic 20) with an aqueous layer on top of the chloroform; thus evaporation of chloroform was avoided and steps for removal of the aqueous phase and transfer of chloroform to cuvettes were omitted to greatly abbreviate the whole procedure.     

Production of High-Viscosity Whey-Glucose Broths by a Xanthomonas campestris Strain

Acclimation of a sandy soil to an air-natural gas mixture stimulated the biological oxidation of chloroform to carbon dioxide. Acetylene and methane inhibited chloroform oxidation. Chloroform oxidation continued up to 31 days in the absence of methane. Chloroform oxidation rates increased at chloroform concentrations up to 5 μg g of soil^-1.     

Wavelength dependence of bilirubin photoreactivity

The rates and products of the self-sensitized photoreactions of bilirubin IXα vary with excitation wavelength, solvent and the presence or absence of oxygen. Radical or Type I photooxidation reactions of bilirubin are implicated in degassed chloroform or methanol. Quantum yields for the disappearance of bilirubin vary from 10^?2 to 10^?4 with excitation wavelengths of 440, 340 and 280 nm and with the higher quantum yield generally appearing in chloroform solvent and/or excitation at 280 nm. Bilirubin is stable in degassed chloroform to irradiation at 440 nm.     

Antiangiogenic,anti-inflammatory and their antioxidant activities of Turnera subulata Sm. (Turneraceae)

Turnera subulata is a substantial medicinal plant used in folk medicine to treat various ailments. The current study was assess the total phenolic and flavonoid contents to evaluate the antioxidant and anti-inflammatory activities of the sequentially extracted T. subulata plant samples. In vitro anti-angiogenic activity was evaluated by chick chorioallantoic membrane (CAM) model for chloroform, ethyl acetate and ethanol extracts. The results obtained revealed that total phenolic content of the chloroform extract (24.13 ± 0.27 mg/g) and total flavonoid content (TFC) of the chloroform extract (22.28 ± 0.40 mg/g) were found to be suggestively higher than the other extracts. A strong antioxidant property was observed for all the six extracts. A study anti-inflammatory activity was observed in chloroform and ethanol extracts, with IC₅₀ ranging from 79 ± 1.01 μg/mL to 81 ± 1.01 μg/mL for protein denaturation assay and from 74 ± 0.11 μg/mL to 76 ± 1.11 μg/mL for HRBC membrane stabilization assay, respectively. The chloroform and ethanol extracts have exhibited good antiangiogenic property. Eventually, these results justified that the chloroform and ethanol extracts of T. subulata with great antioxidant, anti-inflammatory and antiangiogenesis potentials could be promising candidates for the development of a cost effective, potent anticancer drug with minimal side effects.     

Effect of polar solvents on beta-carotene radical precursor

Beta-carotene forms radicals in chloroform upon photo-excitation (i) in the femtosecond time-scale by direct electron ejection into chloroform and (ii) in the microsecond time-scale by secondary reactions with chloroform radicals formed in the faster reactions. The precursor for beta-carotene radical cation decays in a second-order reaction in the mixed solvents, with a rate decreasing for increasing dielectric constant of cosolvent (acetic acid < ethanol < acetonitrile approximately methanol). The precursor is assigned as an ion pair from which the beta-carotene radical cation is formed in neat chloroform, but in more polar solvents it reacts at least partly through disproportionation in a bimolecular reaction promoted by the presence of ions. The stabilization of the radical precursor by increased solvent polarity, allowing for deactivation of the precursor by an alternative reaction channel, is discussed in relation to the balance of pro- and antioxidative properties of beta-carotene at lipid/water interfaces.     

Chloroform in runoff water—a two-year study in a small catchment in Southeast Sweden

Chloroform concentrations were observed and input and output fluxes estimated over a 2-yr period in a small coniferous catchment (0.22 km²) in southeast Sweden. Water discharge was measured daily, and runoff water was sampled bi-weekly for chloroform analysis. An approximate chloroform budget was calculated, which indicated that the annual output of 6 μg m⁻² yr⁻¹ was approximately six times higher than the input, inferring an internal source of chloroform in the catchment. To the best of our knowledge, neither flux estimates nor mass balances have previously been made for chloroform on a catchment scale, nor have data regarding natural runoff variation with time been gathered. Concentrations of chloroform in runoff were found to be generally high during wet periods, such as spring, but also peaked during summer rain events. The observed pattern suggests that chloroform is formed in surface soil layers and transported to the outlet under high-flow conditions and during dry-period rain events; it is lost through degradation or evaporation during drier periods due to longer soil water residence times. The data suggest that the variation among replicates increases with concentration; this emphasizes the need to know what the degree of on-site variation is, so one can collect a sufficient number of replicates to permit detection of spatial or temporal changes.     

Evaluation of in vitro antifungal activity of medicinal plants against phytopathogenic fungi

Fourteen medicinal plants belonging to 13 families were collected and extracted with petroleum ether (PE), chloroform, methanol and water to yield 60 crude extracts. Using agar diffusion method, these extracts were evaluated for antifungal activity on the growth of five phytopathogenic fungi. Among all the extracts tested, PE, chloroform and methanol extracts of Piper betle L. and PE and chloroform extracts of Allamanda cathartica exhibited promising antifungal activity. Minimum inhibitory concentration (MIC) values of the above promising extracts were determined using broth dilution technique and observed that chloroform extract of P. betle L. exhibited the least MIC value ranging from 280 to 1130 μg ml^?1. In this study, we report chloroform extract of P. betle L. to be thermally stable even when steam sterilised for the first time and that it could be stored at 4°C with almost no change in its activity for a period of 180 days.     

Binding of chloroform to mouse and rat hemoglobin

The covalent binding of chemical carcinogens and mutagens to hemoglobin has been proposed as a dose monitor for environmental exposure. The binding of chloroform to hemoglobin in rats was demonstrated to result from the formation of addition adducts to amino acids in the globin. The altered amino acids were isolated with an amino acid analyzer employing ion exchange chromatography. The covalent binding of orally-administered [¹⁴C]chloroform to rat hemoglobin reached a peak within 10 h. Afterwards, the amount of chloroform bound decreased slowly with half remaining at 7 weeks. The extent of chloroform binding was linearly dependent upon dose between 0.1 and 100 μmol/kg. Above 100 μmol/kg chloroform the binding to hemoglobin increased at a reduced rate. The extent of [¹⁴C]chloroform binding resulting from either 10 daily doses of 0.1 μmol/kg or a single 1.0 μmol/kg was similar. The binding to hemoglobin in three strains of mice and rats varied from 85 ± 7 μmol/g Hb for Swiss (CFN) mice to 152 ± 14 for Fisher-344 rats. We have demonstrated that the binding of chloroform to hemoglobin appears to have the following attributes of a dose monitor: (1) easily accessible from laboratory animals (and humans); (2) dose dependent; (3) stability, so that exposure can be determined weeks after it has ceased; (4) integration of low exposures which individually would be undetectable.     

Liposome formulation of NSC-639829 using halothane as a solvent: A technical note

Conclusion  Halothane has been successfully used as a solvent for the liposome formulation of NSC-639829. Liposomes with similar morphology, particle size, incorporation efficiency, and stability were obtained with halothane, chloroform, and ether. Halothane provides additional ease in formulation because of its higher volatility and safety as compared with chloroform and ether. Halothane can be regarded as a safe alternative to chloroform or ether in liposome formulation.     

A versatile modelling approach to determine the hydrophobicity of peptides at the atomic level

This study describes a versatile computational method to determine the hydrophobicity of small peptides at the atomic level. Free energies of transfer for individual atoms in peptide structures were derived, utilising two specifically defined parameters: (i) the water-excluding distance to define the dynamic interface between a peptide solute and its surrounding solvent and (ii) the corresponding hydrophobicity index as a relative measure for water occlusion/repulsion. The method was tested on a range of small peptide models (Ac-X-NH₂, G-X-G, Ac-WL-X-LL and Ac-GG-X-GG-NH₂) and several derivatives of these structures, whereby X was any of the 20 most common amino acids that naturally occur in polypeptides or proteins. The advantage of this new method lies in its versatility, ease to implement and capability to provide information on the hydrophobicity characteristics at the atomic level. The approach also encapsulates the impact of factors that influence these properties, but which have hitherto been difficult to accurately quantify, e.g. steric hindrance or proximity effects due to nearby polarised atoms. The method is not conditional on the knowledge of hydrophobicity parameters from the literature and does not require a sophisticated computer software/hardware to enable the atomic solvent-accessible surface areas or other hydrophobicity parameters to be de novo obtained.