Initial steps in the degradation of benzene sulfonic acid, 4-toluene sulfonic acids,and orthanilic acid in Alcaligenes sp. strain O-1

Alcaligenes sp. strain O-1 grew with benzene sulfonate (BS) as sole carbon source for growth with either NH₄ ⁺ or NH₄ ⁺ plus orthanilate (2-aminobenzene sulfonate, OS) as the source(s) of nitrogen. The intracellular desulfonative enzyme did not degrade 3- or 4-aminobenzene sulfonates in the medium, although the enzyme in cell extracts degraded these compounds. We deduce the presence of a selective permeability barrier to sulfonates and conclude that the first step in sulfonate metabolism is transport into the cell. Cell-free desulfonation of BS in standard reaction mixtures required 2 mol of O₂ per mol. One mol of O₂ was required for a catechol 2,3-dioxygenase. When meta ring cleavage was inhibited with 3-chlorocatechol in desalted extracts, about 1 mol each of O₂ and of NAD(P)H per mol of BS were required for the reaction, and SO₃ ^2- and catechol were recovered in high yield. Catechol was shown to be formed by dioxygenation in an experiment involving ¹⁸O₂. 4-Toluene sulfonate was subject to NAD(P)H-dependent dioxygenation to yield SO₃ ^2- and 4-methylcatechol, which was subject to meta cleavage. OS also required 2 mol of O₂ per mol and NAD(P)H for degradation, and SO₃ ^2- and NH₄ ⁺ were recovered quantitatively. Inhibition of ring cleavage with 3-chrorocatechol reduced the oxygen requirement to 1 mol per mol of OS SO₃ ^2- (1 mol) and an unidentified organic intermediate, but no NH₄ ⁺, were observed.     

Floral scent in dioeciousSalix (Salicaceae)—a cue determining the pollination system?

Floral scents of male and female inflorescences of three dioeciousSalix species were collected by head-space adsorption, and analysed by GC-MS. InSalix caprea andS. cinerea 1,4-dimethoxy benzene was the main compound, and male and female scents showed a high degree of resemblance. No dominant compound was found inS. repens and malefemale scent similarity was low. Floral scent inSalix is likely a strong orientation cue, guiding pollinators between male and female plants ensuring pollen transfer and pollination. We suggest that a high degree of male-female floral scent resemblance is coupled to a high degree of insect pollination. Floral scent does not promote reproductive isolation betweenS. caprea andS. cinerea.     

Phenolic acid effects on peanut growth and oil production

Plants of peanut (Arachis hypogaea L. var. PG No. 1) were given two foliar sprays of phenolic compounds (H-acid, 1, 2, 4-acid, resorcinol and RD-Brown) at 100 and 200 ppm, 35 and 50 days after sowing. In treated plants, shelling %, yield (kg/ha), number of gynophores per plant and number of pods per plant were significantly greater than in the control. Oil content of kernels also showed a significant increase with all the phenolic compounds applied. These compounds increased the linoleic acid concentration so improving nutritional quality. The number of gynophores was significantly correlated with the number of pods per plant and yield per hectare. The effect of phenolic compounds on growth and development was independent of their structural configuration.     

Kinetics of competitive inhibition and cometabolism in the biodegradation of benzene, toluene, and p-xylene by two Pseudomonas isolates

Two Pseudomonas species (designated strains B1 and X1) were isolated from an aerobic pilot-scale fluidized bed reactor treating groundwater containing benzene, toluene, and p-xylene (BTX). Strain B1 grew with benzene and toluene as the sole sources of carbon and energy, and it cometabolized p-xylene in the presence of toluene. Strain X1 grew on toluene and p-xylene, but not benzene. In single substrate experiments, the appearance of biomass lagged the consumption of growth substrates, suggesting that substrate uptake may not be growth-rate limiting for these substrates. Batch tests using paired substrates (BT, TX, or BX) revealed competitive inhibition and cometabolic degradation patterns. Competitive inhibition was modeled by adding a competitive inhibition term to the Monod expression. Cometabolic transformation of nongrowth substrate (p-xylene) by strain B1 was quantified by coupling xylene transformation to consumption of growth substrate (toluene) during growth and to loss of biomass during the decay phase. Coupling was achieved by defining two transformation capacity terms for the cometabolizing culture: one that relates consumption of growth substrate to the consumption of nongrowth substrate, and second that relates consumption of biomass to the consumption of nongrowth substrate. Cometabolism increased decay rates, and the observed yield for strain B1 decreased in the presence of p-xylene. (c) 1993 Wiley & Sons, Inc.     

Resolution of multiple fluorescence lifetimes in heterogeneous systems by phase-modulation fluorometry

Procedures are described for the treatment of phase and modulation lifetime data in fluorescent systems having multiexponential decay. All computer procedures (called FIT programs) arise from the lifetime resolution theory for phase-modulation measurements (Weber, G (1981) J. Phys. Chem. 85, 949–953). The programs most successful in resolving heterogeneous lifetimes use a Monte Carlo approach in which phase and modulation lifetime data at three modulation frequencies are simultaneously utilized. These programs are shown to have more utility than the final closed form procedure presented by Weber (1981). The FIT routines are simple and require little computer time while yielding excellent results. To illustrate the applicability of these programs, defined binary (carbazole and pyrene) and ternary systems (carbazole, pyrene and POPOD) were examined. In most cases, the resolved lifetimes were within 5% of the independently measured value and the fractional fluorescence contributions were within 10% of that expected. These results demonstrate that phase-modulation measurements analyzed by appropriate computer programs are capable of solving for lifetimes in both binary and, in selected cases, ternary systems. An example is given from the recent literature (Dalbey, R., Weiel, J. and Yount, R.G. (1983) Biochemistry 22, 4696–4706) in which the above programs allowed the resolution of both binary and ternary lifetimes of a dansyl label on myosin, where Förster energy transfer was occuring. These lifetimes] were used to quantify changes in distances between two activity-related thiols on myosin upon the addition of Mg-ATP or its analogs.     

Kinetics of aerobic biodegradation of benzene and toluene in sandy aquifer material

Monod's equation adequately described aerobic biodegradation rates of benzene and toluene by the microbial population of a sandy aquifer when these compounds were initially present at concentrations lower than 100 mg/l each. Concentrations higher than 100 mg/l were inhibitory, and no benzene or toluene degradation was observed when these compounds were initially present at 250 mg/l each. The Monod coefficients were calculated as k = 8.3 g-benzene/g-cells/day and Ks = 12.2 mg/l for benzene, and k = 9.9 g-toluene/g-cells/day and Ks = 17.4 mg/l for toluene. Specific first-order coefficients would be 0.68 l/mg.day for benzene and 0.57 l.mg.day for toluene.     

A review of the bioavailability of petroleum constituents

Exposure to petroleum constituents at contaminated sites may occur through a variety of pathways, including inhalation of vapors and particulates, ingestion of water and soils, and dermal contact with water and soils. Accurately assessing the human health risks from such exposures requires information on the medium‐ and route‐specific bioavailability of petroleum constituents (e.g., how well these chemicals enter the body via the gastrointestinal tract and skin). For example, when the medium or exposure route in an animal toxicity assay (e.g., ingestion of water) differs from the actual route of human exposure at the petroleum contaminated site (e.g., dermal contact with soil), adjustments should be made that reflect the relative bioavailability of the chemical in the different media. The focus of this article is on (1) the availability of oral and dermal absorption data for one PAH (benzo[a]pyrene, (B[a]P) and three VOCs in soil (benzene, toluene, and xylene); (2) factors affecting the uptake of these PAHs and VOCs from soil; and (3) ways to incorporate bioavailability data into human health risk assessments. Based on our review, we recommend the following default values for the oral and dermal absorption of B[a]P, benzene, toluene, and xylene from soil:

A review of the bioavailability of petroleum constituents

All authors

Jennifer Bramard & Barbara D. Beck

https://doi.org/10.1080/15320389209383417

Published online:

02 December 2008

Display Table

Site‐specific information such as chemical concentrations in soil, soil characteristics, soil loadings on the skin, contact site, and contact time could result in modifications of these numbers. As shown, our default absorption values are generally less than those recommended by the U.S. EPA (1991a,b,c). The implications of these estimates of bioavailability for risk assessment and for the selection of soil cleanup levels at petroleum‐contaminated sites are discussed.     

LAS inhibition of diffusion and uptake of tritiated uridine during teleost embryogenesis

Synopsis Fathead minnow embryos (Pimephales promelas Rafinesque) of 5 different developmental ages (5, 33, 48, 72 and 96 hrs after fertilization) were used as controls and exposed for 2 hrs to a solution of 0.25 Ci ml^–1 of³H-Uridine. Another set of embryos (5, 33, 48, 72 and 96 hrs after fertilization) were subjected to the same treatment except that during the one hour immediately preceding the³H-Uridine incubation, the control embryos were placed in water while the experimental embryos were placed in water containing 15 ppm 11.2 LAS. In both cases, radiation counts minute^–1 embryo^–1 and per milligram of embryo increased over the 4 day developmental period. The embryos with LAS treatment displayed lower radiation counts at all ages as compared to controls, indicating an inhibition of diffusion and uptake of³H-Uridine and/or RNA synthesis. The possible mechanism of LAS is discussed.     

Urinary and air biomonitoring of occupational exposure to benzene in oil pit workers

Abstract

The purpose of this study is to evaluate the personal exposure to benzene and its relationship with biomonitoring and quantitative risk assessment among the personnel working and living near oil pits. This study was conducted in one of oil subsidiary companies in Kharg in 2017. Airborne benzene exposure was evaluated over 8-h periods during work-shift by using personal active samplers. Urinary O-Cresol levels were determined using GC-FID for separation and detection. The highest mean concentration of airborne benzene was at monitoring location, A (0.53?ppm), monitoring location H (0.59?ppm) in the spring, monitoring location M (0.72?ppm) and monitoring location P (0.8?ppm) in the summer, which was more than suggested by the American Conference of Governmental Industrial Hygienists. No direct linear relationship was found between the concentration of airborne benzene, age, work experience, urinary creatinine, and O-Cresol in this study (p?>?.05). No significant difference was observed between urinary O-Cresol and benzene in occupational groups and different seasons (p?>?.05). The highest mean quantitative risk of cancers was observed in summer (1.21?±?0.47). According to the results of this study, urinary biomarker O-Cresol is not a suitable measure for evaluating exposure to environmental benzene.     

Eremophilane Sesquiterpenes and Benzene Derivatives from the Endophyte Microdiplodia sp. WGHS5

Three new eremophilane sesquiterpenes phomadecalins G−I ( 1 – 3 ) and two new benzene derivatives microdiplzenes A and B ( 12 and 13 ), together with nine known eremophilane sesquiterpenes ( 4 – 11 and 14 ) were isolated from an endophytic fungus, Microdiplodia sp. WGHS5. Their structures were elucidated by the interpretation of HR-ESI-MS and NMR data; meanwhile, the absolute configurations of new compounds were determined on the base of ECD calculations. All compounds were evaluated for the antimicrobial activities and antiproliferative effect on human gastric cancer cell lines (BGC-823).