Distribution of Free Seleno-amino Acids in Plant Tissue ofMelilotus indicaL. Grown in Selenium-Laden Soils

Accumulation of specific groups of seleno-amino acids in plant tissue reflects not only the Se tolerance of a plant species, but also Se toxicity to animals. The distribution of seleno-amino acids in a Se-tolerant grassland legume species (Melilotus indicaL.) grown in Se-laden soils was studied using high-resolution gas chromatography-and gas chromatography-mass spectrometry. Five seleno-amino acids including selenocystine, selenomethionine, selenocysteine, Se-methylselenocystine, andγ-glutamyl-Se-methylselenocysteine were identified and measured for their plant tissue concentrations. Se-methylselenocysteine, a nonprotein seleno-amino acid, was found in the plant tissue. Its concentration ranged from 15.3 μmol kg⁻¹for the plants growing in soil of low Se concentration to 109.8 μmol kg⁻¹for the plants grown in soil of high Se concentration. Accumulation of the nonprotein seleno-amino acid in this species resembles that in Se accumulator plants.γ-Glutamyl-Se-methylselenocysteine was detected in the plant. However, its concentration was very low. It might not become a toxic element in the food chain. Results of plant tissue Se accumulation analysis indicated that there was a five-fold increase in tissue selenocysteine concentration when the total tissue Se increased from 5.07 to 22.02 mg kg⁻¹, but there was no further increase in tissue selenocysteine concentration when the tissue total Se concentration increased from 22.0 to 117.4 mg kg⁻¹. Selenomethinone constituted more than 50% of the total seleno-amino acid in the plant. More research is needed to reveal whether the mechanisms limiting the accumulation of selenocysteine and preferential accumulation of selenomethionine found in this study play any role in Se tolerance in this species.     

Effect of Metal-Tolerant Plant Growth-Promoting <Emphasis Type="Italic">Rhizobium</Emphasis> on the Performance of Pea Grown in Metal-Amended Soil

The nickel- and zinc-tolerant plant growth-promoting (PGP) Rhizobium sp. RP5 was isolated from nodules of pea, grown in metal-contaminated Indian soils. The PGP potentials of strain RP5 was assessed under in vitro conditions. Strain RP5 displayed a high level of tolerance to nickel (350 μg ml⁻¹) and zinc (1500 μg ml⁻¹) and showed PGP activity under in vitro conditions. The PGP activity of this strain was further assessed with increasing concentrations of nickel and zinc, using pea as a test crop. The bio-inoculant enhanced the dry matter, nodule numbers, root N, shoot N, leghemoglobin, seed yield, and grain protein (GP) by 19%, 23%, 26%, 47%, 112%, 26%, and 8%, respectively, at 290 mg Ni kg⁻¹ while at 4890 mg Zn kg⁻¹ soil, it increased the dry matter, nodule numbers, leghemoglobin, seed yield, GP, and root and shoot N by 18%, 23%, 78%, 26%, 7%, 25%, and 42%, respectively, compared to plants grown in soil amended with metal only. The bio-inoculant increased the glutathione reductase activity of roots and nodules by 46% and 65% at 580 mg Ni kg⁻¹ and 47% and 54% at 9780 mg Zn kg⁻¹ soil, respectively, compared to uninoculated plants. The inoculated strain decreased the concentration of nickel and zinc in plant organs. The intrinsic abilities of nitrogen fixation, growth promotion, and the ability to reduce the toxicity of nickel and zinc of the tested strain could be of practical importance in augmenting the growth and yield of pea, in nickel- and zinc-polluted soils.     

Toxicity Assessment of Herbicides Quizalafop-p-Ethyl and Clodinafop Towards Rhizobium Pea Symbiosis

In modern conventional agriculture, herbicides are frequently used to prevent yield losses due to weeds. Herbicides also affect negatively the productivity of legumes. With these considerations, we evaluated the effects of soil applications of different concentrations of quizalafop-p-ethyl and clodinafop on the performance of Rhizobium inoculated pea, grown in clay pots. In this study, the concentration of herbicides higher than the recommended rates of quizalafop-p-ethyl and clodinafop adversely affected the dry matter accumulation, symbiotic properties, grain yield and nutrient status of pea plants. Toxicity of quizalafop-p-ethyl and clodinafop to pea plants increased progressively with increase in rates of herbicides. Of the two herbicides, quizalafop-p-ethyl was more toxic than clodinafop. In contrast, when herbicide tolerant Rhizobium strain MRP1 was also used with herbicide, it increased the measured parameters at all concentrations. A maximum increase of 11%, 17%, 46%, 33%, 21% and 7% in the root N, shoot N, root P, shoot P, seed yield and seed protein, respectively, was observed when MRP1 was used with 120 μg quizalafop-p-ethyl kg⁻¹ soil while with 1,200 μg clodinafop kg⁻¹ soil it increased the root N, shoot N, root P, shoot P, seed yield and seed protein by 20%, 9%, 56%, 56%, 29% and 7%, respectively, compared with the un-inoculated but herbicide treated control. This study suggested that the toxic effects of herbicides on pea plants could be attenuated by applying growth promoting herbicide tolerant strain of Rhizobium under herbicide stressed soil environment.     

Absorption and distribution of selenium in animals consuming canola grown for selenium phytoremediation

Canola (Brassica napus) grown as a selected plant species for field phytoremediation of selenium (Se) may be harvested and utilized as Se-enriched forage for marginally Se-deficient lambs and cows. Two field studies were conducted under controlled conditions to evaluate the accumulation of Se into different animal tissues, including blood, excreta, and milk. In Study 1, treatments consisted of feeding lambs freshly cut Se-enriched canola (containing approximately 4 mg Se kg(-1) DM) or control canola (containing <0.1 mg Se kg(-1) DM), respectively, for 64 days. In Study 2, treatments consisted of feeding cows dried Se-enriched canola (containing approximately 3.5 mg Se kg(-1) DM) as part of their daily ration for 20 days. In Study 1 at postmortem, Se concentrations were significantly greater in all tested tissues and in excreta from lambs fed Se-enriched canola. In Study 2, Se values were slightly higher in blood and excreta, but not significantly higher in milk from cows sampled throughout the study. Significant differences in total live animal weight were not observed between treatments in either study. Based on these results, canola plants (not including seeds) used for field phytoremediation of Se may be harvested and safely fed to lambs and cows to help meet normal Se intake requirements.     

Bioextraction of Selenium by Forage and Selected Field Legume Species in Selenium-Laden Soils under Minimal Field Management Conditions

A forage plant, tall fescue (Festuca arundinacea), and a selected field legume species, sour clover (Melilotus indica), were examined for their selenium (Se) bioextraction abilities in Se-laden soils under minimal management conditions. Natural vegetations in a 2-acre plot adjacent to the forage plots were also studied for Se accumulation comparisons. During the dry season, in the fall of 1994, the field plots were either irrigated weekly or without irrigation. No fertilization and weed control were applied. The plants were harvested in May 1995. There were considerable differences in the ability of Se uptake between the forage and the legume species and among the naturally established plant species; the amount of Se accumulated per land area was largely dependent on their respective biomass production. Comparing Se concentration between preplant and postharvest, there was a detectable reduction in the soil selenate, selenite, and water-extractable organic Se in the tall fescue and melilotus plots. The field irrigation provided more favorable conditions for bioextractions and dissipation of Se by the plants. However, the available soil Se only accounts for less than 10% of the total soil Se and no detectable reduction of total soil Se was found. This may be due to the large inventory and variation of Se concentrations in the field soils and therefore obscured the detectable differences. For practical considerations, the forage plants can be repeatedly harvested and used for rangelands of Se deficiency currently seen in some northern California counties.     

Phytoremediation of stable Cs from solutions by Calendula alata, Amaranthus chlorostachys and Chenopodium album

Uptake rate of ¹³³Cs, at three different concentrations of CsCl, by Calendula alata, Amaranthus chlorostachys and Chenopodium album plants grown outdoors was studied. These plants grow abundantly in semi-arid regions and their varieties exist in many parts of the world. When exposed to lowest Cs concentration 68 percent Cs was remediated by Chenopodium album.¹³³Cs accumulation in shoots of Amaranthus chlorostachys reached its highest value of 2146.2 mg kg⁻¹ at a ¹³³Cs supply level of 3.95 mg l⁻¹ of feed solution. The highest concentration ratio value was 4.89 for Amaranthus chlorostachys, whereas for the other tests it ranged from 0.74 to 3.33. Furthermore uptake of ¹³³Cs by all three species increased with increasing metal concentrations. The results also indicated that hydroponically grown Calendula alata, Amaranthus chlorostachys and Chenopodium album could be used as potential candidate plants for phytoremediation of solutions contaminated with Cs.     

Plant Uptake and Translocation of Inorganic and Organic Forms of Selenium

Selenium (Se) plays a role in human health: It is an essential trace element but can be toxic if too much is consumed. The aim of this study was to determine which species of Se are most rapidly taken up and translocated to above-ground plant tissues. Specifically, we wished to determine if organic forms of Se in an exposure solution can contribute to the amount of Se found in shoot tissue. Durum wheat (Triticum turgidum) and spring canola (Brassica napus) were grown hydroponically, and young seedlings were exposed to 0.5 or 5.0 μM Se as selenate, selenite, seleno-methionione, or seleno-cystine for ≤300 min. Canola accumulated more Se than wheat, although the difference depended on Se speciation of the exposure solution. Organic forms of Se were taken up at a greater rate than inorganic forms. When exposed to 5.0 μM Se, the rate of uptake of selenite was 1.5- (canola) or 5-fold (wheat) greater than the rate of uptake of selenate, whereas seleno-methionine was taken up 40- (canola) or 100-fold (wheat) faster and seleno-cystine 2- (wheat) to 20-fold (canola) faster. Plants exposed to seleno-methionine had the highest shoot concentrations of Se even though selenate was more mobile once taken up; in plants exposed to selenate >50 % of accumulated Se was translocated to shoot tissue. Because organic forms of Se (especially seleno-methionine) can be readily taken up and translocated to above-ground tissues of wheat and canola, these Se species should be considered when attempting to predict Se accumulation in above-ground plant tissues.     

Effects of Elevated Selenium and Salinity Concentrations in Root Zone on Selenium and Salt Secretion in Saltgrass (Distichlis spicataL.)

The effects of elevated selenium (Se) and salinity concentrations in the root zone on Se and salt secretion and accumulation were studied for an inland (Kesterson) and a coastal (Bodega Bay) saltgrass in sand culture and under greenhouse conditions. The results of this study indicate that the secretory mechanism of the saltgrass exhibits high ion specificity. Plants of both ecotypes were more efficient at Cl⁻and Na⁺secretion than at SO₄²⁻and Se secretion, suggesting that the saltgrass secretion mechanism is adapted primarily to saline environments high in NaCl. The saltgrass plants of the Kesterson ecotype secreted more Se than the Bodega Bay plants when treated with Se alone. However, the Bodega Bay plants secreted more Se than the Kesterson plants when the plants were treated with Se + NaCl. These differences reflect a ecotypical difference in which the Kesterson plants are more adaptive to the seleniferous soil, and the Bodega Bay plants are more adaptive to a coastal saline soil high in NaCl. Sulfate availability inhibited both Se accumulation and Se secretion in the plants of both ecotypes by approximately 98%. Ion secretion molar ratios of Na:Cl were calculated and the results suggest that Na⁺secretion is dependent on the availability of Cl⁻. Selenium was taken up by plants with little discrimination, and thus it may be regarded as a master of chemical mimicry sharing similar physical and chemical properties with sulfur (S). Selenium and salt accumulation indices and secretion efficiency indices were calculated and found that the accumulation indices were higher for Se than for S, suggesting that Se uptake may be more passive and less regulated by active transport than S. Secretion efficiency was much higher for Na⁺and Cl⁻than for Se and SO₄²⁻, but the efficiency indices between ecotypes were comparable, suggesting that the secretion mechanism in this species is designed mainly for adaptation of high NaCl concentrations. About 85% of the secreted Se was found in selenate form. This finding suggests that the mechanism of Se translocation and Se secretion in the saltgrass resembles the movement of selenate in xylem found in nonhalophytic plants. Less than 15% of organic Se was detected in the secretions and only trace amount of selenite was detected. Overall, the Se secretion mechanism in saltgrass does not seem to contribute substantial Se speciation in the plant soil system.     

Bioaccumulation and Chemical Form of Chromium in <Emphasis Type="Italic">Leersia hexandra</Emphasis> Swartz

The chromium bioaccumulation ability of Leersia hexandra was assessed and the chromium distribution in the deferent chemical forms in plant tissues was determined. The hydroponic experimental results indicated that the maximum chromium concentration in the dry leaf matter of Leersia hexandra reached 4302 mg kg⁻¹. Chromium treatment could significantly increase the proportions of oxalic integrated chromium in leaves and residue chromium in roots, which might be related to the high resistance and bioaccumulation capacity for chromium in Leersia hexandra. Xuehong Zhang, Jie Liu these authors contributed equally to this work.     

Daily Dietary Selenium Intake in a High Selenium Area of Enshi,China

Enshi is a high selenium (Se) region in Hubei, China, where human selenosis was observed between 1958 and 1963. This study investigated the daily dietary Se intake of residents in Shadi, a town located 72 km northeast of Enshi City, to assess the risk of human selenosis in the high Se area. Foods consumed typically by the local residents and their hair samples were analyzed for total Se concentration. Concentrations of Se in different diet categories were as follows: cereals: 0.96 ± 0.90 mg kg⁻¹ DW in rice and 0.43 ± 0.55 mg kg⁻¹ DW in corn; tuber: 0.28 ± 0.56 mg kg⁻¹ in potato and 0.36 ± 0.12 mg kg⁻¹ in sweet potato; vegetables: ranging from 0.23 ± 1.00 mg kg⁻¹ in carrot to 1.57 ± 1.06 mg kg⁻¹ in kidney bean; animal proteins: 1.99 ± 1.11 mg kg⁻¹ in chicken and egg. Based on the food Se concentrations and the daily per-capita consumption, the estimated daily Se intake in Shadi was 550 ± 307 µg per capita. Moreover, the Se concentrations in the hairs of local adult residents were 3.13 ± 1.91 mg kg⁻¹ (n = 122) and 2.21 ± 1.14 mg kg⁻¹ (n = 122) for females and males, respectively, suggesting that females might be exposed to higher levels of Se from daily cooking. Although there was no human selenosis occurrence in recent years, the high level of the daily Se intake suggested that the potential risk of selenosis for local residents, especially females, might be a matter of concern.     

Selenium accumulation in submerged aquatic macrophytes Potamogeton pectinatus L. and Ruppia maritima L. from water with elevated chloride and sulfate salinity.

Submerged aquatic macrophyte species Potamogeton crispus L. (curlyleaf pondweed) and Ruppia maritima L. (widegeongrass) were examined for selenium accumulation from agricultural drainage water in the field and under laboratory conditions. High concentrations of chloride and sulfate salts were found in the drainage water of the constructed wetland at Tulare Lake Drainage District, Corcorn, California. Samples of P. crispus and R. maritima collected from the field, had similar plant-tissue Se concentrations, but the rhizomes accumulated significantly greater amounts of Se than the shoot tissues. When the plants were grown in culture solution supplemented with either chloride or sulfate salt, R. maritima was found to be more salt tolerant than P. crispus, and P. crispus accumulated more Se than R. maritima. Free seleno-amino acids were detected in the plant tissue, and organic Se was detected in the culture solution after 10 days of growth. The release of organic Se into the water by the plants may have a negative impact on the wetland environment.     

Anomalous accumulation of selenium by genetically modified potato,stable to Colorado beetle

Although ordinary and genetically modified potatoes stable to Colorado beetles (CPB), Leptinotarsa decemlineata Say, are known to possess very small differences in chemical composition, nothing is known about selenium (Se) accumulation by these plants. Using a fluorimetric method of analysis, we have demonstrated extremely high Se accumulation in leaves of CPB-resistant potatoes (more than 1 mg kg^?1 dry weight) and moderate accumulation levels of Se in tubers (1.39 times more than in ordinary plants). Leaves of genetically modified potatoes are shown to possess a decreased concentration of ascorbic acid (1.5 times less than controls) and slightly elevated levels of nitrates. The possibility of Se participation in the protection of genetically modified potatoes against CPB is discussed.     

Profile of polyphenols and phenolic acids in bracts and receptacles of globe artichoke (Cynara cardunculus var. scolymus) germplasm

The aim of this work was to assess and quantify polyphenols and hydroxycinnamic acids in different parts of the heads of 6 globe artichoke cultivars by HPLC-DAD-MS/MS. Globe artichoke (Cynara cardunculus var. scolymus) has been used in folk medicine since Roman times, possibly because of high hydroxycinnamic acid and flavone levels. However, to our knowledge, little is known about how these compounds are distributed in different parts of the artichoke head (outer bracts, inner bracts and receptacle). The phenolic profile was significantly different between cultivars and in different parts of the head, suggesting that individual compounds are accumulated preferentially in specific head parts and cultivars. In particular, the phenolic profile of the outer bracts exhibits very low (443 mg kg⁻¹ dry matter) or zero hydroxycinnamic acid content, and these compounds are present mainly in the receptacle (the edible part; mean value, 1473 mg kg⁻¹ dry matter). This study presents data that indicate the different levels of phenolics in different parts of artichoke, and shows the potential of various artichoke parts as a source of different levels of dietary phenolics.     

Effects of selenium diets on growth, accumulation and antioxidant response in juvenile carp

An 8-week feeding trial was undertaken with Cyprinus carpio to determine the effects of two commercial Se diets (HSe 1.0 mg kg⁻¹ and LSe 0.25 mg kg⁻¹) on growth, accumulation and antioxidant response in juveniles at time 0, 30 and 60 days. HSe carp had higher mean weight (W) values than LSe group at 60 days and the Fulton condition factor (K) indicated good fish health for both diet groups. Among the investigated HSe tissues, kidney and liver were mainly involved in Se accumulation, whereas the Se level in muscle indicated a very low Se contamination risk for human health. Selenium accumulation levels in HSe tissues followed this order: kidney>liver>muscle. Although growth was not impaired, biochemical antioxidant indicators in liver and kidney evidenced an oxidative stress condition in HSe juveniles. Furthermore, selenium supplementation levels, higher than the one employed in this study, might worsen the antioxidant status of carp.     

Variability of biogenic amine and free amino acid concentrations in regionally produced goat milk cheeses

The free amino acid composition and biogenic amine content were analysed in pasteurised goat milk cheeses produced in different regions in Spain. These goat cheeses are made with pasteurised milk to which a mesophilic starter culture is added; they are enzymatically coagulated, uncooked, pressed cheeses. They have a firm texture with a slight but typical goat milk aroma and flavour. The total free amino acids varied markedly among the samples, ranging from 1400 to 28,000 mg kg⁻¹ DM (dry matter). Of the 20 amino acids analysed, the most abundant were leucine, proline, valine, glutamic acid, lysine, glutamine, ornithine and γ-aminobutyric acid, which accounted for over 60% of the total free amino acids. The goat milk cheeses presented low concentrations of biogenic amines, the most abundant being tyramine and/or histamine, with values ranging from 4.2 to 50.7 and from 10.2 to 60.5 mg kg⁻¹ DM, respectively. Total biogenic amine content ranged between 26.4 mg kg⁻¹ DM and 175.1 mg kg⁻¹ DM, and was always below the level that is considered dangerous for humans. Therefore, taking into consideration the concentrations of BAs, these goat milk cheeses, produced under good hygienic conditions, can be considered safe for consumers.     

Phytotoxicity of PFOS and PFOA to Brassica chinensis in different Chinese soils

PFOS and PFOA are potential persistent organic pollutants that have raised many concerns in recent years. Research focusing on phytotoxicity of PFOS and PFOA to higher plants is necessary for their risk assessments. However, few toxicity data exist for PFOS or PFOA and higher plants. Here we investigated phytotoxicity of PFOS and PFOA to Brassica chinensis root growth in six different Chinese soils varying widely in soil properties using a standardized root length assay. The effective concentrations of added PFOS and PFOA causing 50% inhibition (EC₅₀) ranged from 95 to >200 mg kg⁻¹ for PFOS and from 107 to 246 mg kg⁻¹ for PFOA, respectively, representing more than 2.1- and 2.3-fold variation among the tested soils. Regressions of soil PFOS and PFOA toxicity threshold values (EC_x and NOECs) with various soil properties showed that the amount of organic matter was the most significant factor affecting their toxicity to B. chinensis.     

Responses of Cynara cardunculus L. to single and combined cadmium and nickel treatment conditions

A greenhouse pot experiment was carried out to study the responses of Cynara cardunculus L. (cardoon) to cadmium and nickel. Three groups of 12 pots each were planted with cardoon plants and spiked with single and combined cadmium and nickel aqueous solutions. The bioavailable metal concentrations, measured in soil, ranged widely and were up to 246.7 mg kg⁻¹ for Cd and 61.1 mg kg⁻¹ for Ni. Under Cd treatment, cardoon growth remained unaffected, while increased Ni soil concentrations inhibited plant growth and were lethal to the highly treated plants. In the combined Cd and Ni treatments, an antagonistic effect was observed between the two metals. Cadmium and nickel concentrations in cardoon tissues rose with increasing metal concentrations in the soil. Cadmium and nickel contents in shoots reached 169.3 and 342.3 mg kg⁻¹ in the single treatments while, under the combined Cd and Ni treatments, they were up to 235.0 and 440.7 mg kg⁻¹, respectively. Generally, mean contents of both metals in the shoots were higher than in the roots and the translocation factor was greater than 1. A possible enhancing effect of nickel on cadmium uptake was observed. Cardoon showed characteristics of a Cd accumulator.     

Soil and foliar application of selenium in rice biofortification

Selenium (Se) is essential for humans and animals because of its antioxidant properties, which form part of a series of chemical reactions. The aim of this study was to evaluate the effect of different Se application forms and sources on rice growth, grain yield, and rice Se concentration and accumulation, as well the content of N, P, Mg, S, B, Cu, Fe, Mn, and Zn in rice grains. The experiment was carried out in a greenhouse with 4-dm³ pots containing a sandy clay loam Red-Yellow Latosol. The experimental design was a completely randomized 2 × 2 × 2 factorial scheme (two Se doses × two forms of Se application, soil or foliar × two Se sources, selenate or selenite), with five replicates. Selenium in rice plants was analyzed by total reflection X-ray fluorescence spectrometry (TXRF). The results shows that soil selenate application was more effective for shoot dry matter production and grain Se accumulation than selenite. Foliar application of both selenate and selenite increased grain yield. This study provides useful information concerning agronomic biofortification of rice, showing that both soil and foliar Se application could be used for increasing Se content in edible parts, which could result in health benefits.     

Reduction in Cardiovascular Disease Risk Factors: 6-Month Results from ProjectActive

Background.ProjectActiveis a randomized clinical trial that compares a lifestyle physical activity intervention with a traditional structured exercise intervention. The purpose of this paper is to report 6-month results of these interventions on cardiovascular disease (CVD) risk factors among healthy, sedentary, middle-aged men and women, and to examine the psychological strategies used in each group (Lifestyle and Structured) to reach the level of physical activity recommended by the Centers for Disease Control and Prevention (CDC) and American College of Sports Medicine (ACSM) and to achieve changes in these CVD risk factors.Methods.A total of 116 initially sedentary men (mean ± SD self-reported physical activity, 33.2 ± 1.4 kcal · kg⁻¹· day⁻¹) and 119 women (32.9 ± 1.0 kcal · kg⁻¹· day⁻¹), ages 35–60 years (46.0 ± 6.7 years) were randomly assigned to a 6-month lifestyle physical activity counseling intervention or a 6-month gymnasium-based structured program. At baseline and 6 months, changes in lipid and lipoprotein-cholesterol concentrations, blood pressure, and body composition and cognitive and behavioral measures of change were assessed. One-way analyses of variance with covariate adjustment were used to test for between-group differences in CVD risk factors. Associations between achieving the CDC/ACSM criterion and changes in cognitive and behavioral measures were assessed with multiple logistic regression models.Results.After 6 months of intervention, 78% of Lifestyle participants and 85% of Structured participants were meeting or exceeding the CDC/ACSM recommendation of accumulating 30 min or more of moderate-intensity physical activity on most, preferably all, days of the week. This was verified by a significant increase in cardiorespiratory fitness in both groups. The adjusted mean increase in maximal METs (VO_2peak÷ 3.5 ml · kg⁻¹· min⁻¹) between treadmill tests was 0.4 kcal · kg⁻¹· hr⁻¹(P< 0.001) for Lifestyle and 1.1 kcal · kg⁻¹· hr⁻¹(P< 0.001) for Structured. There was a significant difference between intervention groups for this outcome. Both groups had significant reductions in total cholesterol, total cholesterol/HDL-C ratio, diastolic blood pressure, and percentage of body fat. There were no significant between-group differences in changes in these outcomes. Adjusted mean changes in total cholesterol, systolic blood pressure, and percentage of body fat in Lifestyle [in Structured] participants were −0.2 [−0.3] mmol · L⁻¹, −3.2[−1.8] mm Hg, and −1.4 [−1.7] %, respectively. There were significant associations between achieving the CDC/ACSM physical activity criterion and greater use of the cognitive and behavioral strategies of change. Both groups changed self-efficacy and many of the behavioral measures, but there were no significant differences between intervention groups.Conclusions.These results demonstrate that lifestyle physical activity counseling is as effective as structured exercise programs in increasing physical activity and improving CVD risk factors after 6 months among initially sedentary men and women. Furthermore, specific cognitive and behavioral counseling strategies were increased significantly as a result of the intervention. These strategies are effective and could be used in a wide variety of settings.     

Soil-Based Phytotoxicity of 2,4,6-Trinitrotoluene (TNT) to Terrestrial Higher Plants

Seed germination and early stage seedling growth tests were conducted to determine the ecotoxicological threshold of 2,4,6-trinitrotoluene (TNT) in two soils of different properties. Soils were amended up to 1,600 mg TNT kg⁻¹ soil and four representative species of higher plants, two dicotyledons (Lepidium sativum L., common name: cress; and Brassica rapa Metzg., turnip) and two monocotyledons (Acena sativa L., oat; and Triticum aestivum L., wheat), were assessed. Cumulative seed germination and fresh shoot biomass were measured as evaluation endpoints. Phytotoxicity of TNT was observed to be affected by soil properties and varied between plant species. Cress and turnip showed higher sensitivity to TNT than did oat and wheat. The lowest observable adverse effect concentration (LOAEC) of TNT derived from this study was 50 mg kg⁻¹ soil. In contrast to high TNT concentrations, low levels of TNT, i.e., 5–25 mg kg⁻¹ soil for cress and turnip and 25–50 mg kg⁻¹ for oat and wheat, stimulated seedling growth. Oat was capable of tolerating as much as 1,600 mg TNT kg⁻¹ and demonstrated a potential ability of TNT detoxification in one of the soils tested, suggesting that this plant might be useful in the bioremediation of TNT contaminated soils. Received: 15 May 1998/Accepted: 30 September 1998