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PubMed1984

Disposition of [14C]2,3-dichloropropene in Fischer-344 rats after oral or intraperitoneal administration.

2,3-Dichloropropene (2,3-DCP), a component of commercial fumigants and nematocides, was mixed with [14C]2,3-DCP and given to rats by peroral (p.o.) or intraperitoneal (i.p.) administration. Urine, feces, and expired air were collected over 72 h. Excretion of radioactivity in urine predominated over other routes, with 66% to 75% of the dose excreted in 72 h. Feces contained from 13% to 21% of dose. 8% of the dose was exhaled as 14CO2. At the end of 72 h, only 2% to 3% of the dose remained in the carcass with the highest concentrations of 14C in liver, kidney, testes, and lung. Approx. 91% of the p.o. dose was absorbed from the gastrointestinal (GI) tract.

Administration, Oral↗
PubMed2005

Ozone sensitivity of currant tomato (Lycopersicon pimpinellifolium), a potential bioindicator species.

The wild tomato species Lycopersicon pimpinellifolium (currant tomato) was exposed to different O3 concentration, both in controlled environment fumigation facilities and in open-top chambers, to assess its sensitivity and to verify its potential as a bioindicator plant. Plants appeared particularly sensitive to O3 at an early stage of growth, responding with typical chlorotic spots within 24 h after exposure to a single pulse of 50 ppb for 3 h, and differentiating peculiar symptoms, such as reddish necrotic stipples, bronzing and extensive necrosis, depending on O3 concentration. Histo-cytochemical investigations with 3,3'-diaminobenzidine, to localize H2O2, and Evans blue, to detect dead cells, suggested that currant tomato sensitivity to O3 could be due to a deficiency in the anti-oxidant pools. The combination of these stainings proved to be useful, either to predict visible symptoms, early before their appearance, and to validate leaf ozone injury.

Biomarkers↗
PubMed2006

Ozone induced leaf loss and decreased leaf production of European Holly (Ilex aquifolium L.) over multiple seasons.

European Holly (Ilex aquifolium L.) was used to study the impact of one short (28 day) ozone fumigation episode on leaf production, leaf loss and stomatal conductance (g(s)), in order to explore potential longer term effects over 3 growing seasons. Young I. aquifolium plants received an episode of either charcoal-filtered air or charcoal-filtered air with 70 nl l(-1) O(3) added for 7 h d(-1) over a 28 day period from June 15th 1996, then placed into ambient environment, Stoke-on-Trent, U.K. Data were collected per leaf cohort over the next three growing seasons. Ozone exposure significantly increased leaf loss and stomatal conductance and reduced leaf production over all subsequent seasons. Impact of the initial ozone stress was still detected in leaves that had no direct experimental ozone exposure. This study has shown the potential of ozone to introduce long-term phenological perturbations into ecosystems by influencing productivity over a number of seasons.

Biomass↗
PubMed2006

Ozone stress and antioxidant substances in Trifolium repens and Centaurea jacea leaves.

Ozone-sensitive (NC-S clone) and resistant plants (NC-R clone) of Trifolium repens and Centaurea jacea were exposed to moderate ozone concentrations in ambient air. The aim of this study was the investigation of the relation between ozone-sensitivity and leaf concentrations of antioxidants (ascorbic acid, total phenolics and total antioxidant capacity). NC-R clone showed the highest concentrations of antioxidants with 50-70% more ascorbic acid than NC-S. NC-R had about 5 times more ascorbic acid in the young leaves and 9 times more in the old leaves than Centaurea. In a fumigation experiment with acute ozone stress (100 nl L(-1)) the antioxidant levels changed profoundly. The ozone-injured leaves of NC-S had 6-8 times more total phenolics than uninjured leaves. Generally older leaves had lower antioxidant concentrations and were more prone to ozone injury than younger leaves. Ascorbic acid concentrations were closer related to the appearance of visible ozone injury than the other antioxidative parameters.

Antioxidants↗
PubMed2005

Impact of elevated H(2)S on metabolite levels, activity of enzymes and expression of genes involved in cysteine metabolism.

The effects of elevated atmospheric hydrogen sulfide (H(2)S) levels (0.25, 0.5, and 0.75 microl l(-1)) have been investigated in a short-term exposure experiment (3-48 h) on the model plant Arabidopsis thaliana (L.) Heynh. in comparison to untreated control plants. The most pronounced effects of H(2)S fumigation could be observed on the metabolite level: the contents of the thiols cysteine and glutathione were increased up to 20- and fourfold, respectively. A direct positive correlation of the thiol contents with the H(2)S concentrations applied was observed. To elucidate the molecular basis for the increased thiol levels, enzyme activities, messenger RNA and protein steady-state levels of cysteine-synthesizing and degrading pathways have been determined. The enzyme activities of O-acetyl-l-serine(thiol)lyase (OAS-TL) (EC 4.2.99.8) and l-cysteine desulfhydrase (EC 4.4.1.-) proteins were not significantly higher at elevated H(2)S levels in comparison to untreated control plants. 3-Mercaptopyruvate sulfurtransferase (EC 2.8.1.2) activity was slightly higher after the longest H(2)S exposure times. Elevated H(2)S levels of 0.25 and 0.5 microl l(-1) had promoting effects on both mRNA and protein levels of cysteine-synthesizing and degrading enzymes whereas the highest H(2)S concentrations caused lower levels of expression combined with mild symptoms of oxidative stress, as the consequence of its phytotoxicity. The differences in the expression of the three different OAS-TL isoforms (cytoplasmic, plastidic and mitochondrial) by H(2)S were very small. Increasing concentrations of H(2)S and longer exposure times to H(2)S let to a reduction in the pool of O-acetyl-l-serine, the second precursor of cysteine, and N-acetyl-l-serine in the leaves and shoots, indicating a substrate depletion in agreement with the increased thiol levels.

Arabidopsis↗
PubMedDate not supplied

A 'cyanoacrylate case' for developing fingerprints in cars.

A portable case has been developed by which cyanoacrylate (super glue) fuming can be used inside a vehicle suspected of being involved in serious crime. The car itself serves as a fumigation chamber and the cyanoacrylate vapours are fed into the car via a hose. Connected to the hose and suspended inside the car is a vapour diffuser. The cyanoacrylate originates from a portable case where there is a sealed heater and also a command panel with hygrometer and thermometer for a technician to control the process. There is also space inside the case for other necessary equipment.

Automobiles↗
PubMed2006

Quantification of jasmonic acid by SPME in tomato plants stressed by ozone.

Jasmonates are signalling molecules induced in plants as a response to various biotic and/or abiotic stresses. As ozone is known to activate defense responses in plants, we have monitored the concentration of jasmonic acid in tomato leaves during and after an acute exposure to this abiotic elicitor. In this experiment, we observed that the maximum induction of jasmonic acid in O3-fumigated plants occurred 9 h after the end of treatment and the concentration of jasmonic acid in stressed plants increased 13-fold. However, the level of endogenous methyl-jasmonate was constant during the observed period. The extraction and quantification of jasmonic acid as its methyl ester was performed by headspace-solid-phase microextraction (or HS-SPME) in combination with GC-FID and GC-MS. The sensitivity (LOD = 2 ng/g) of this method permitted the detection and quantification of jasmonic acid present in plant tissues at very low concentrations.

Chromatography, Gas↗
PubMed1993

Tobacco plants transformed with the O-acetylserine (thiol) lyase gene of wheat are resistant to toxic levels of hydrogen sulphide gas.

O-acetylserine (thiol) lyase (EC4.2.99.8) is the key enzyme in the cysteine biosynthetic pathway of plants and prokaryotes. The gene, cys1, encoding this enzyme was isolated from a wheat (Triticum aestivum L.) cDNA library, and its deduced amino acid sequence found to show 53% sequence identity with the O-acetyl-serine (thiol) lyase of Escherichia coli and Salmonella typhimurium. The deduced peptide consists of 325 amino acids (34.1 kDa), contains a conserved motif for the binding of pyridoxal phosphate, a co-factor required for enzymatic activity, and an N-terminal region of 37 amino acid residues resembling chloroplast transit peptides. The identity of cys1 was further demonstrated through complementation of an E. coli cysteine auxotroph, which lacks O-acetylserine (thiol) lyase, by expression of the wheat gene. Northern blot analysis showed that cys1 is highly expressed in green vegetative and reproductive tissues and in the roots of wheat, as well as in the leaves of several plant species. Southern blot analysis demonstrated that the gene exists as a single copy in the wheat genome. Tobacco plants transformed with cys1 in the sense orientation (sense plants) or antisense orientation (antisense plants), under the control of the CaMV 35S promoter, showed high levels of transcripts. The O-acetylserine (thiol) lyase activity in transgenic plants was determined, and found to be three- to fivefold higher in sense plants than in control plants, but unaffected in antisense transformants. Fumigation experiments with toxic levels of hydrogen sulphide (H2S) gas showed that while sense transformants were highly resistant, control and antisense plants were severely damaged by the treatment.

Amino Acid Sequence↗
PubMed2001

Quantitative estimation of flagellate community structure and diversity in soil samples.

Heterotrophic flagellates occur in nearly all soils and, in most cases, many different species are present. Nevertheless, quantitative data on their community structure and diversity are sparse, possibly due to a lack of suitable techniques. Previous studies have tended to focus on either total flagellate numbers and biomass, or the identification and description of flagellate species present. With the increased awareness of the role of biodiversity and of food web interactions, the quantification of species within the community and their response to environmental change is likely to become more important. The present paper describes a modification of the most probable number method that allows such a quantification of individual flagellate morphotypes in soil samples. Observations were also made on the biomass of flagellate morphotypes in soil. 20 to 25 morphotypes of heterotrophic flagellates were detectable per gram of two different arable soils, which were treated experimentally to test the technique. One of the soils was fumigated with chloroform vapour for different lengths of time (0, 0.5, 2 or 24 hours); this led to a reduction in the number of morphotypes, in the Shannon diversity index and in the evenness. The other soil was planted with wheat, and while rhizosphere soils contained the same morphotypes as bulk soil, the abundance of individual morphotypes was significantly different and the Shannon diversity index in rhizosphere soils was significantly higher. Soil influenced by an elevated CO2 level likewise differed significantly in morphotype abundance when compared to soil exposed to ambient levels of CO2. The technique recovered more than 80% of the discernible morphotypes and could also be used to quantify amoebal and ciliate communities in a similar way.

Animals↗
PubMed1976

The effect of methods of sterilization on the nutritive value of protein in a commercial rat diet.

1. The effect on protein quality of treating a commercial rat diet by autoclaving at various temperatures for different periods of time, or by irradiation with 2-5 or 10 Mrd, was studied. True digestibility (TD) and biological value (BV) were measured and the available and total amino acids in the diets were estimated using microbiological and chemical methods. 2. Autoclaving at 121 degrees for 60 min reduced BV, TD and net protein utilization (NPU) more than autoclaving at 134 degrees for 3 min. Availability of amino acids was reduced by both treatments but to a greater extent by autoclaving at 121 degrees for 60 min. Total amino acids were essentially unaffected. Irradiation had no effect on BV, TD, NPU or total amino acids, and the availability of amino acids was also unaffected, with the exception of lysine which was slightly reduced. 3. When the diet was autoclaved at 115 or 121 degrees for 15, 30 or 60 min, or at 134 degrees for 3 min the availability of the amino acids was reduced with increasing time and temperature of treatment. Treatment at 134 degrees for 3 min had an effect on available amino acids similar to treatment at 121 degrees for 15 or 30 min. 4. Ethylene oxide fumigation of the diet caused reduced availability of histidine, methionine and tryptophan but had negligble effect on arginine, leucine and lysine. 5. It is concluded that from a practical point of view irradiation causes least damage to proteins in rodent diets. If such diets are to be autoclaved they should be supplemented with complete protein to counteract amino acid destruction.

Amino Acids↗
PubMed2003

Short-term effects of hydrogen fluoride on Nicotiana tabacum L.

Data on the short-term effects of fumigation with hydrogen fluoride (HF) on the response behavior of the Nicotiana tabacum L. cv. St. Karabalar 6265 are being presented. Growth rate, fluoride accumulation in leaves and soils, and degradation in chlorophyll and nicotine contents of the plant species against the variations in two experimental factors, namely the exposure concentration and exposure time parameters, were investigated. Resulting data reveals that the variety selected for this study is not so tolerant to fluoride as generally reported in the literature, if only the individual effects of the pollutant is considered.

Air Pollutants↗
PubMed2003

Influence of elevated CO2 and O3 on Betula pendula Roth crown structure.

Elevated CO(2) and ozone effects were studied singly and in combination on the crown structure of two Betula pendula clones. Measurements were made at the end of the second fumigation period in an open-top-chamber experiment with 9-year-old trees. Shoot ramification (number of long and short daughter shoots), shoot length, and number of metamers, leaves and buds were measured at four positions in every tree. As a result of increased temperature, trees in chambers had longer shoots and more frequent shoot ramification than control trees not enclosed in chambers. Ozone treatment decreased shoot ramification significantly. Additionally, ozone treatment resulted in an increased number of metamers in one clone. There was no statistically significant interaction between ozone effect and crown position; however, there was a slight tendency for the lower crown to be more affected by ozone. Elevated CO(2) caused a significant increase in the number of long-shoot metamers. Therefore, 2x ambient CO(2) concentration partly ameliorated the negative effect of ozone because the increased number of leaves per shoot counteracted the decreased branching. Although the main effects of elevated ozone and CO(2) were similar in the two clones, slight, statistically insignificant, differences appeared in their responses when interactions with crown position were considered.

Betula↗
PubMed2004

Toxicity of propylene oxide at low pressure against life stages of four species of stored product insects.

The relative toxicity of propylene oxide (PPO) at a low pressure of 100 mm Hg to four species of stored product insect at 30 degrees C over a 4-h exposure period was investigated. PPO at 100 mm Hg was toxic to all four species tested: Tribolium castaneum (Herbst), Plodia interpunctella (Hübner), Ephestia cautella (Wlk.), and Oryzaephilus surinamensis (L.). There were differences in susceptibility between the life stages of the tested insect species. Mortality tests on all life stages of the insects resulted in LD99 values ranging from 4.7 to 26.1 mg/liter. The pupal stage of E. cautella, O. surinamensis, and T. castaneum was the most tolerant stage with LD99 values of 14.4, 26.1, and 25.7 mg/liter, respectively. For P. interpunctella, the egg stage was most tolerant, with a LD99 value of 15.3 mg/liter. Generally, PPO at 100 mm Hg was more toxic to P. interpunctella and E. cautella than to O. surinamensis and T. castaneum. A 99% mortality of all life stages of the tested species was achieved at a concentrations x time product of 104.4 mg h/liter. These findings indicate that a combination of PPO with low pressure can render the fumigant a potential alternative to methyl bromide for rapid disinfestation of commodities.

Animal Feed↗
PubMed2004

Toxicity of plant essential oils to Tetranychus urticae (Acari: Tetranychidae) and Phytoseiulus persimilis (Acari: Phytoseiidae).

Fifty-three plant essential oils were tested for their toxicity against eggs and adults of Tetranychus urticae Koch as well as adults of Phytoseiulus persimilis Athias-Henriot, by using a filter paper diffusion bioassay without allowing direct contact. Responses varied according to oil type and dose, and mite species. In a plastic container (4.5 by 9.5 cm) bioassay at 14 x 10(-3) microl/ml air, caraway seed, citronella java, lemon eucalyptus, pennyroyal, and peppermint oils gave > 90% mortality against adult T. urticae, whereas 82 and 81% mortality was observed with sage and spearmint oils, respectively. With the exception of sage oil, the other six essential oils were highly effective against T. urticae eggs at 9.3 x 10(-3) microl/ml air. Against adult P. persimilis, these six test oils caused > 90% mortality at 7.1 x 10(-3) microl/ml air. Particularly peppermint oil at 4.7 x 10(-3) microl/ml air was highly toxic. In an acrylic cage (30 by 30 by 40 cm ) test, lemon eucalyptus, pennyroyal, peppermint, and spearmint oils were highly effective against adult T. urticae at 1.4 x 10(-3) microl/ml air. These results indicate that the mode of delivery of these essential oils was largely a result of action in the vapor phase via the respiratory system. The essential oils described herein merit further study as potential fumigants for T. urticae control.

Animals↗
PubMed1990

The effects of controlled exposure to formaldehyde vapour on spores of Bacillus globigii NCTC 10073.

The effects of exposure of spores of Bacillus globigii NCTC 10073 to controlled levels of formaldehyde vapour under varying environmental conditions are reported. The death rate of the micro-organism varies with the humidity and formaldehyde concentration and can be predicted for conditions within the limits of the information available. A mathematical model for the effects of formaldehyde is proposed which can be used to calculate the effects of known conditions and as the basis of a controlled formaldehyde fumigation process. Results of practical tests of such a process are described.

Bacillus↗
PubMed1976

The effect of dazomet on salmonellas on artificially contaminated eggs.

Salmonellas were isolated from the surface of only 1 of 21 artificially contaminated eggs after they had been treated with dazomet. By comparison salmonellas were isolated from the surface of 13 of the 21 untreated eggs. Penetration by the salmonellas through the shells to the shell membranes resulted from the immersion of warm eggs in a cold suspension of salmonella cells. While the dazomet treatment reduced the incidence of salmonellas within the shells and shell membranes, elimination of salmonellas from all eggs was not achieved. However, the numbers of surviving salmonellas on the eggs were small; a count of 4 per shell being recorded compared to greater than 110,000 per shell of the untreated eggs. The failure to achieve complete elimination of salmonellas within the shell and membranes appeared to be due to inadequate penetration of the fumigant to these structures.

Animals↗