Bioavailability and extraction of heavy metals from contaminated soil by Atriplex halimus

Pot experiments were performed to evaluate the phytoremediation capacity of plants of Atriplex halimus grown in contaminated mine soils and to investigate the effects of organic amendments on the metal bioavailability and uptake of these metals by plants. Soil samples collected from abandoned mine sites north of Madrid (Spain) were mixed with 0, 30 and 60 Mg ha⁻¹ of two organic amendments, with different pH and nutrients content: pine-bark compost and horse- and sheep-manure compost. The increasing soil organic matter content and pH by the application of manure amendment reduced metal bioavailability in soil stabilising them. The proportion of Cu in the most bioavailable fractions (sum of the water-soluble, exchangeable, acid-soluble and Fe–Mn oxides fractions) decreased with the addition of 60 Mg ha⁻¹ of manure from 62% to 52% in one of the soils studied and from 50% to 30% in the other. This amendment also reduced Zn proportion in water-soluble and exchangeable fractions from 17% to 13% in one of the soils. Manure decreased metal concentrations in shoots of A. halimus, from 97 to 35 mg kg⁻¹ of Cu, from 211 to 98 mg kg⁻¹ of Zn and from 1.4 to 0.6 mg kg⁻¹ of Cd. In these treatments there was a higher plant growth due to the lower metal toxicity and the improvement of nutrients content in soil. This higher growth resulted in a higher total metal accumulation in plant biomass and therefore in a greater amount of metals removed from soil, so manure could be useful for phytoextraction purposes. This amendment increased metal accumulation in shoots from 37 to 138 mg pot⁻¹ of Cu, from 299 to 445 mg pot⁻¹ of Zn and from 1.8 to 3.7 mg pot⁻¹ of Cd. Pine bark amendment did not significantly alter metal availability and its uptake by plants. Plants of A. halimus managed to reduce total Zn concentration in one of the soils from 146 to 130 mg kg⁻¹, but its phytoextraction capacity was insufficient to remediate contaminated soils in the short-to-medium term. However, A. halimus could be, in combination with manure amendment, appropriate for the phytostabilization of metals in mine soils.     

A microcosm study on bioremediation of fenitrothion-contaminated soil using Burkholderia sp. FDS-1

Fenitrothion, a toxic organophosphorus pesticide, can build up the concentration of nitrophenolic compound in soils and hence needs to be removed. Burkholderia sp. FDS-1, a fenitrothion-degrading strain, was used in this work to study factors affecting its growth, and then evaluated for its capacity to degrade fenitrothion in soil microcosms. Minimal salt medium containing 1% (w/v) glucose was found to be a suitable carbon source for inoculum preparation. Various factors, including soil pH, temperature, initial fenitrothion concentration, and inoculum size influenced the degradation of fenitrothion. Microcosm studies performed with varying concentrations (1–200 mg kg⁻¹) of fenitrothion-spiked soils showed that strain FDS-1 could effectively degrade fenitrothion in the range of 1–50 mg kg⁻¹ soil. The addition of Burkholderia sp. FDS-1 at 2×10⁶ colony forming units g⁻¹ soil was found to be suitable for fenitrothion degradation over a temperature range of 20–40 °C and at a slight alkaline pH (7.5). The results indicate that strain FDS-1 has potential for use in bioremediation of fenitrothion and its metabolite-contaminated sites. This is a model study that could be used for decontamination of sites contaminated with other compounds.     

Response of native grasses and Cicer arietinum to soil polluted with mining wastes: Implications for the management of land adjacent to mine sites

Mine tailings are an environmental problem in Southern Spain because wind and water erosion of bare surfaces results in the dispersal of toxic metals over nearby urban or agricultural areas. Revegetation with tolerant native species may reduce this risk. We grew two grasses, Lygeum spartum and Piptatherum miliaceum, and the crop species Cicer arietinum (chickpea) under controlled conditions in pots containing a mine tailings mixed into non-polluted soil to give treatments of 0%, 25%, 50%, 75% and 100% mine tailings. We tested a neutral (pH 7.4) mine tailings which contained high concentrations of Cd, Cu, Pb and Zn. Water-extractable metal concentrations increased in proportion to the amount of tailings added. The biomass of the two grasses decreased in proportion to the rate of neutral mine-tailing addition, while the biomass of C. arietinum only decreased in relation to the control treatment. Neutron radiography revealed that root development of C. arietinum was perturbed in soil amended with the neutral tailings compared to those of the control treatment, despite a lack of toxicity symptoms in the shoots. In all treatments and for all metals, the plants accumulated higher concentrations in the roots than in shoots. The highest concentrations occurred in the roots of P. miliaceum (2500 mg kg^?1 Pb, 146 mg kg^?1 Cd, 185 mg kg^?1 Cu, 2700 mg kg^?1 Zn). C. arietinum seeds had normal concentrations of Zn (70–90 mg kg^?1) and Cu (6–9 mg kg^?1). However, the Cd concentration in this species was ～1 mg kg^?1 in the seeds and 14.5 mg kg^?1 in shoots. Consumption of these plant species by cattle and wild fauna may present a risk of toxic metals entering the food chain.     

Assessment of Lemna gibba L. (duckweed) as a potential ecological indicator for contaminated aquatic ecosystem by boron mine effluent

Duckweeds, as a group, are important early warning indicators for the assessment of contaminated ecosystems due to their propensity to accumulate pollutants. In the present study, we investigated the potential use of Lemna gibba L. (Lemnaceae) as an ecological indicator for boron (B) mine effluent containing B concentration above 10 mg l⁻¹. For this purpose, L. gibba fronds were grown for 7 days in simulated water contaminated with B mine effluent. The important note is that this study was carried out in Kırka (Eskişehir, Turkey) B reserve area, which is the largest borax reserve in all over the world, under natural climatic conditions in the field. The results demonstrated that accumulations of B by L. gibba gradually increased based on the initial B concentrations (10, 25, 50, 100, and 150 mg l⁻¹) of the mine effluent. B concentration in the dry weight of the plant reached 639 mg kg⁻¹ when the minimum initial dosage (10 mg l⁻¹) was applied and 2711 mg kg⁻¹ when the maximum initial dosage (150 mg l⁻¹) was applied during the study. However, significant reductions in their relative growth rates occurred in 50, 100 and 150 mg l⁻¹ initial B concentrations. Results suggest that 25 mg l⁻¹ B concentration in water seemed to be a sensitive endpoint for L. gibba that could be used as a critical bioindicator level of B contaminated water. Following our data, we also constructed a simple growth model under the climatic conditions in this region of Turkey, but in instructive as a worldwide model. L. gibba is, therefore, suggested to be able to use as both an indicator and a phytoremediation tool because of its high accumulation capacity for B contaminated water.     

Beef cattle pasture to wetland reconversion: Impact on soil organic carbon and phosphorus dynamics

There is a major need to understand the historical condition and chemical/biological functions of the ecosystems following a conversion of wetlands to agricultural functions. To better understand the dynamics of soil total organic carbon (TOC) and phosphorus (P) during beef cattle pastures to wetland reconversion, soil core samples were collected from the beef cattle pasture and from the natural wetland at Plant City, FL, during five summer seasons (2002–2007). The levels of TOC and soil P were significantly affected by changing land use and hydrology. Draining natural wetlands to grazed pastures resulted in very pronounced reduction of TOC from 180.1 to 5.4 g g^?1. Cumulative concentrations of total phosphorus (TP) in soils (1134 mg kg^?1) under drained condition are two to three times lower than those in soils (2752 mg kg^?1) under flooded condition over the periods of land use reconversion. There was a declining trend (r = 0.82**; p ≤ 0.01) in total soil P from natural wetland (763 mg kg^?1) to altered pastures (340 mg kg^?1), largely as organic-bound P (natural wetland, 48%; grazed pastures, 44%; altered pastures, 29%). These results are important in establishing baseline information on soil properties in pasture and wetland prior to restoring and reconverting pasture back to wetland conditions. The results further suggest that changes in soil properties due to changing land use and hydrologic conditions (drying and re-wetting) could be long lasting.     

Assessment of germination and carnivorous activities of a nematode-trapping fungus Arthrobotrys dactyloides in fungistatic and fungicidal soil environment

Carnivorism is the ability of nematode-trapping fungi to trap and digest the nematodes by sophisticated devices called traps. Delivery of nematode-trapping fungi in soil for bio-control of pest nematodes often fails or gives inconsistent results. Possible reasons for failure could be the effect of soil fungistasis on germination of nematode-trapping fungi in soil environment, use of avirulent species and sensitivity of these fungi to fungicidal residues in soil. Exploitation of nematode-trapping fungi for nematode control demands that it be compatible with fungicides applied in soil or crops and proliferate in soil. This investigation represents is one of the first to evaluate the effect of fungicides on the nematode-trapping fungus Arthrobotrys dactyloides. A. dactyloides showed in vitro carnivorous potential against Meloidogyne incognita, Meloidogyne javanica, Meloidogyne graminicola, Helicotylenchus dihystera and Heterodera cajani. Conidia of A. dactyloides exposed to agricultural soils showed poor germination but formed conidial traps, which captured and killed the soil nematodes. Conidial traps, which trapped the nematodes, grew well in all soils after killing and nutrient absorption from nematode body. Soil amended with 20 mg ai kg⁻¹ of carbendazim and thiram, 30 mg ai kg⁻¹ of mancozeb, 50 mg ai kg⁻¹ of captan, and 100 mg ai kg⁻¹ of carboxin completely checked the conidial trap formation and nematode capturing. 30, 50 and 100 mg ai kg⁻¹ of metalaxyl adversely affected the conidial trap formation and nematode capturing in soil. Propiconazole inhibited 15.2% conidial trap formation up to 50 mg ai kg⁻¹ but caused 93.3% inhibition of conidial traps formation and complete inhibition of nematode capturing at 100 mg ai kg⁻¹. Sulphur, triademefon, and tricyclazole showed least toxic effect on conidial trap formation and nematode capturing activities of A. dactyloides in soil up to 100 mg ai kg⁻¹.     

The collembola Lobella sokamensis juvenile as a new soil quality indicator of heavy metal pollution

We propose Lobella sokamensis Deharveng and Weiner, 1984 juvenile as a new soil quality indicator to assess heavy metal polluted soils. L. sokamensis is a collembola commonly found with earthworms, and it plays a key role in decomposing dead earthworms. The soil quality assessment of cadmium (Cd), copper (Cu), antimony (Sb), and zinc (Zn) on the survival of L. sokamensis adults were performed in artificial soil. The LC50 values for L. sokamensis adults exposed to Cd, Cu, Sb and Zn for 5 days were calculated to be 4729, 4472, 4702, and 2521 mg kg⁻¹, respectively. L. sokamensis juveniles (10–12 days) were also exposed to Cd, Cu, Sb, and Zn, and 5 days-LC50 values for Cd, Cu, Sb, and Zn were 282, 229, 447, and 163 mg kg⁻¹, respectively. Both adult and juvenile survivals of L. sokamensis in metal spiked soil were inhibited. We found that the soil quality assessment using L. sokamensis juveniles were sensitive enough to evaluate soil pollution, compared to conventional Folsomia candida assay which is widely used. In addition, L. sokamensis has advantage for easy detection in soil due to the big and orange-colored body. The 5 days-soil quality assessment using L. sokamensis juveniles appears to be rapid protocols for the collembola assay. This is the first report on the collembola assay of heavy metal contaminated soils using the L. sokamensis as a soil indicator.     

Trace amounts of nickel in belowground rhizomes of Vaccinium myrtillus L. decrease anthocyanin concentrations in aerial shoots without water stress

Nickel (Ni) may impair plant water balance through detrimental effects on the belowground level. Bilberry (Vaccinium myrtillus L.) plants were grown in a mesic heath forest-type soil and subjected to Ni sulphate (NiSO₄·6H₂O) concentrations of 0, 10, 50, 100 and 500 mg m⁻² during an entire growing season in northern Finland (65°N). Biomass of belowground rhizomes, and tissue water content (TWC) and anthocyanin concentrations of aerial shoots were determined from mature plants in order to study rhizospheric Ni stress, and its possible long-distance effects on aerial shoots. As the major proportion of biomass of bilberry is invested in belowground parts, it was hypothesised that Ni-induced rhizospheric disturbance causes water stress in aerial shoots and increases their anthocyanin concentrations for osmotic regulation. Uptake of Ni from the soil to the rhizome and aerial shoots was measured with X-ray fluorescence spectrometry. Ni concentrations in the soil and rhizome exhibited a dose–response relationship, but the concentrations in the rhizome were about 10-fold lower (<3 mg Ni kg⁻¹) than those in the soil (<30 mg Ni kg⁻¹). Translocation of Ni from the rhizome to aerial shoots did not occur, as Ni concentrations in shoots remained at 1 mg Ni kg⁻¹. Although Ni concentrations in the rhizome were below the threshold values of Ni toxicity (i.e. 10–50 mg Ni kg⁻¹), Ni decreased the rhizome biomass. Anthocyanins decreased in aerial shoots along with the Ni accumulation in the rhizome, while TWC was unaffected. The result suggests that anthocyanins are not involved in osmotic regulation under Ni stress, since anthocyanins in aerial shoots responded to the Ni concentrations in the rhizome despite the lack of water stress.     

Reducing nutrient loss from farms through silvopastoral practices in coarse-textured soils of Florida,USA

Trees integrated into the range- and pasturelands of Florida could remove nutrients from deeper soil profiles that would otherwise be transported to water bodies and cause pollution. Soil nitrogen (N) and phosphorus (P) concentrations were monitored in three pastures: a treeless pasture of bahiagrass (Paspalum notatum); a pasture of bahiagrass under 20-year-old slash pine (Pinus elliotti) trees (silvopasture); and a pasture of native vegetation under pine trees (native silvopasture). Soil analysis from 10 profiles within each pasture showed that P concentrations were higher in treeless pasture (mean: 9.11 mg kg⁻¹ in the surface to 0.23 mg kg⁻¹ at 1.0 m depth) compared to silvopastures (mean: 2.51 and 0.087 mg kg⁻¹, respectively), and ammonium–N and nitrate–N concentrations were higher in the surface horizon of treeless pasture. The more extensive rooting zones of the combined stand of tree + forage may have caused higher nutrient uptake from silvopastures than treeless system. Further, compared to treeless system, soils under silvopasture showed higher P storage capacity. The results suggest that, compared to treeless pasture, silvopastoral association enhances nutrient retention in the system and thus reduces chances for nutrient transport to surface water. The study reflects the scope for applying ecological-engineering and ecosystem-restoration principles to silvopastoral-system design.     

Apocynum venetum: A newly found lithium accumulator

Apocynum venetum has antidepressant and anxiolytic effects according to the traditional Chinese medicine. Lithium (Li) is a proven mood stabilizer. According to the similar drug efficacy, we hypothesized that A. venetum may contain high levels of Li. Here, we investigated Li tolerance and accumulation potential of A. venetum in the field and in greenhouse cultivation. Li concentration in leaves of A. venetum was substantially higher than that of its main accompanying plants. Under a soil Li supply of 50 mg kg⁻¹ the plant did not show obvious symptom of phytotoxicity. Rather, A. venetum could accumulate >1800 mg kg⁻¹ Li in leaf tissues, and survived still under 400 mg kg⁻¹ Li supply. The bioconcentration factor (except control) and translocation factor values were greater than 1.0. Thus, A. venetum has the characteristics of, at least, a Li-accumulator, if not a Li-hyperaccumulator. A. venetum may serve as an interesting model species to study the influence of Li on plants.     

Evaluation of phosphorus distribution and bioavailability in sediments of a subtropical wetland reserve in southeast China

The phosphorus (P) fractions and bioavailable P in the sediments from the Quanzhou Bay Estuarine Wetland Nature Reserve were investigated using chemical extraction methods for the first time to study the distribution and bioavailability of P in the reserve sediments. A hypothesis was presented suggesting that the bioavailable P in the sediments could be evaluated using the P fractions. The total phosphorus (TP), inorganic phosphorus (IP), organic phosphorus (OP), non-apatite phosphorus (NAIP), and apatite phosphorus (AP) contents in the sediments were in the ranges of 303.87–761.59 mg kg⁻¹, 201.22–577.66 mg kg⁻¹, 75.83–179.16 mg kg⁻¹, 28.86–277.90 mg kg⁻¹, and 127.36–289.94 mg kg⁻¹, respectively. The water soluble phosphorus (WSP), readily desorbable phosphorus (RDP), algal available phosphorus (AAP), and NaHCO₃ extractable phosphorus (Olsen-P) contents in the sediments were in the ranges of 0.58–357.17 mg kg⁻¹, 80.77–586.75 mg kg⁻¹, 1.09–24.12 mg kg⁻¹, and 54.96–676.82 mg kg⁻¹, respectively. The correlation analysis results showed that the NAIP was the major component of the bioavailable P and that the impact of the AP on the bioavailable phosphorus may be minimal. Due to the low TP content in the sediments of the Quanzhou Bay Estuarine Wetland Nature Reserve, the potential pollution risks of P in the sediments may not be very high. The results also show that the bioavailable P concentrations in the sediments of the Quanzhou Bay Estuarine Wetland Nature Reserve could not be evaluated by measuring the P fractions and that the hypothesis was untenable.     

Preventive effect of rikkunshito on gastric motor function inhibited by l-dopa in rats

We previously reported that ghrelin prevented l-dopa (LD)-induced inhibition of gastric emptying (GE) of a non-nutrient solution in rats. Parkinson's disease treatment involves the combined administration of l-dopa with the enzyme l-amino acid decarboxylase inhibitor, carbidopa (CD) to reduce peripheral formation of dopamine. We investigated the effect LD/CD given orogastrically (og) on GE of a non-nutrient or nutrient meal and whether og pretreatment with rikkunshito, a kampo medicine clinically used to treat gastroparesis, influenced LD/CD effect on GE and postprandial antral and duodenal motility in conscious rats. LD/CD (20/2 mg kg⁻¹) decreased significantly GE to 26.3 ± 6.0% compared to 61.2 ± 3.2% in og vehicle monitored 20-min after a non-nutrient meal and to 41.9 ± 5.8% compared to 72.9 ± 5.2% in og vehicle monitored 60 min after a nutrient meal. Rikkunshito (0.5 or 1.0 g kg⁻¹) reduced the LD/CD (20/2 mg kg⁻¹) inhibition of GE of non-nutrient meal (36.9 ± 7.4% and 46.6 ± 4.8% respectively vs. 12.1 ± 7.4% in og vehicle plus LD/CD) while having no effect alone (56.6 ± 8.5%). The ghrelin antagonist, [d-Lys³]-GHRP-6 (1 mg kg⁻¹) injected intraperitoneally partially reversed rikkunshito preventive effect on LD/CD-inhibited GE. Rikkunshito (1.0 g kg⁻¹) blocked LD/CD (20/2 mg kg⁻¹)-induced delayed GE of a nutrient meal and the reduction of postprandial antral motility. In 6-hydroxydopamine-induced Parkinson's disease rat model, rikkunshito (1.0 g kg⁻¹, og) also prevented LD/CD-inhibited gastric emptying of a nutrient meal and enhanced fasting plasma levels of acylated ghrelin. These data indicate that oral rikkunshito alleviates the delayed GE induced by LD/CD in naïve and PD rat model in part through ghrelin-related mechanisms.     

Evaluation of zinc tolerance and accumulation potential of the coastal shrub Limoniastrum monopetalum (L.) Boiss.

The coastal shrub Limoniastrum monopetalum is capable of growth in soil containing extremely high concentrations of heavy metals. A greenhouse experiment was conducted in order to investigate the effects of a range of Zn concentrations (0–130 mmol l⁻¹) on growth and photosynthetic performance, by measuring relative growth rate, total leaf area, plant height, gas exchange, chlorophyll fluorescence parameters and photosynthetic pigment concentrations. We also determined the total zinc, nitrogen, phosphorus, sulphur, calcium, magnesium, sodium, potassium, iron and copper concentrations in the plant tissues. The study species demonstrated hypertolerance to Zn stress, since survival was recorded with leaf concentrations of up to 1700 mg Zn kg⁻¹ dry mass when treated with 130 mmol Zn l⁻¹. L. monopetalum exhibited little overall effects on photosynthetic function at Zn levels of up to 90 mmol l⁻¹. At greater external Zn concentration, plant growth was negatively affected, due in all probability to the recorded decline in net photosynthetic rate, which may be linked to the adverse effect of the metal on photosynthetic electron transport. Growth parameters were virtually unaffected by leaf tissue concentrations as high as 1400 mg Zn kg⁻¹ dry mass thus indicating that this species could play an important role in the phytoremediation of Zn-polluted areas.     

Selenium uptake,speciation and stressed response of Nicotiana tabacum L.

The research on the function and mechanism of selenium (Se) is of great significance for the development of Se-enriched agricultural products. In this paper, uptake, speciation distribution, the effects on the flue-cured tobacco growth and antioxidant system of Se at different levels (0–22.2 mg Se kg⁻¹) were studied through a pot experiment, aiming to clarify flue-cured tobacco's response to Se stress and the relationship between Se speciation and antioxidant system. The results showed that the leaf area and number, the biomass and the chlorophyll content reached the maximum at 4.4 mg kg⁻¹ of Se treatment. Selenium at low levels (≤4.4 mg kg⁻¹) stimulated the growth of flue-cured tobacco by elevating the capability of antioxidant stress and reducing the malondialdehyde (MDA) content to 0.6–0.8 times of that of the control. However, high Se levels (≥11.1 mg kg⁻¹) depressed the capability of antioxidant stress and raised the MDA content to 1.5-fold of that of the control, and meanwhile the biomass of the aboveground parts and underground parts declined notably. The Se content in different parts of flue-cured tobacco significantly increased with the growth of Se levels. The range of Se content in roots, leaves and stems at 2.2–22.2 mg kg⁻¹ of Se treatment were 16.7–58.6 mg kg⁻¹, 2.6–37.3 mg kg⁻¹ and 2.2–10.3 mg kg⁻¹, respectively. According to the detection of different Se speciation, only selenocysteine (SeCys) was detectable in leaves at 2.2 mg kg⁻¹ Se treatment; SeCys, selenite [Se(IV)]and selenate [Se(VI)] were detected in flue-cured tobacco leaves at Se treatment (≥4.4 mg kg⁻¹), which accounted for 4.6–10%, 9–18.7% and 71–86% respectively; SeCys, selenomethionine (SeMet) and Se(IV) were detected in roots, and organic selenium(66–84%) was the main Se species at Se ≤ 11.1 mg kg⁻¹ treatment; four Se species [SeCys, SeMet, Se(IV) and Se(VI)] were detected in flue-cured tobacco roots, and the main Se species was inorganic Se (60%) at 22.2 mg kg⁻¹ Se treatment. That was to say, the percentage of organic Se species (SeCys and SeMet in flue-cured tobacco leaves and root) declined, whereas the ratio of inorganic Se species [Se(IV) and Se(VI)] increased with the growth of Se levels. The correlation analysis showed that the superoxide dismutase (SOD) activity as well as the glutathione (GSH) and MDA contents were positively correlated with the Se(IV) and Se(VI) contents at P < 0.01 and excessive inorganic Se might destruct the reactive oxygen species (ROS) balance and enhance the MDA content, thus causing damage to the plant growth. In a word, the present study suggested that the ratio of inorganic Se [Se(IV) and Se(VI)] was closely related with the growth and the antioxidant capacity of flue-cured tobacco and the excessive application of Se led to the higher proportion of inorganic Se and poorer antioxidant capacity, which ultimately inhibited the growth of flue-cured tobacco.     

In vivo antimicrobial evaluation of an alanine-rich peptide derived from Pleuronectes americanus

In several organisms, the first barrier against microbial infections consists of antimicrobial peptides (AMPs) which are molecules that act as components of the innate immune system. Recent studies have demonstrated that AMPs can perform various functions in different tissues or physiological conditions. In this view, this study was carried out in order to evaluate the multifunctional activity in vivo of an alanine-rich peptide, known as Pa-MAP, derived from the polar fish Pleuronectes americanus. Pa-MAP was evaluated in intraperitoneally infected mice with a sub-lethal concentration of Escherichia coli at standard concentrations of 1 and 5 mg kg⁻¹. At both concentrations, Pa-MAPs exhibited an ability to prevent E. coli infection and increase mice survival, similar to the result observed in mice treated with ampicillin at 2 mg kg⁻¹. In addition, mice were monitored for weight loss. The results showed that mice treated with Pa-MAPs at 1 mg kg⁻¹ gained 0.8% of body weight during the 72 h of experiment. The same was observed with Pa-MAP at 5 mg kg⁻¹, which had a gain of 0.5% in body weight during the treatment. Mice treated with ampicillin at 2 mg kg⁻¹ show a significant weight loss of 5.6% of body weight. The untreated group exhibited a 5.5% loss of body weight. The immunomodulatory effects were also evaluated by the quantification of IL-10, IL-12, TNF-α, IFN-γ and nitric oxide cytokines in serum, but no immunomodulatory activity was observed. Data presented here suggest that Pa-MAP should be used as a novel antibiotic against infection control.     

A pilot study of synbiotic supplementation on breast milk mineral concentrations and growth of exclusively breast fed infants

Despite the crucial role of breast milk mineral contents for health and growth of the infants, they decrease with the duration of lactation. So, this pilot study aimed to determine the effects of synbiotic supplementation on breast milk mineral composition and infants’ growth. In this pilot, randomized, double-blind, placebo-controlled trial, 57 lactating mothers were randomly divided into two groups to receive a daily supplement of synbiotic (n = 30) or a placebo (n = 27) for 30 days. Breast milk zinc, copper, Iron, magnesium and, calcium concentrations were determined by flame atomic absorption spectrometry. Weight for age Z-score (WAZ) and height for age Z-score (HAZ) were assessed for infants. Dietary intake was collected from lactating women using the 24-h recall method. Data analyses were carried out using nutritionist IV, Epi Info and SPSS soft wares. Synbiotic supplementation led to an insignificant increase of the mean breast milk levels of zinc (from 2.44 ± 0.65 to 2.55 ± 0.55 mg L⁻¹), copper (from 0.35 ± 0.24 to 0.40 ± 0.26 mg L⁻¹), iron (from 0.28 ± 0.42 to 0.31 ± 0.38 mg L⁻¹), magnesium (from 17.14 ± 1.35 to 17.17 ± 1.09 mg L⁻¹), and calcium (from 189 ± 25.3 to 189.9 ± 21.7 mg L⁻¹); whilst in the placebo group, these variables decreased significantly (P = 0.001). The observed changes between two groups were statistically significant (P < 0.05). Although WAZ and HAZ of infants increased slightly in the supplemented group (from 1.19 ± 0.79 to 1.20 ± 0.69 and 0.36 ± 0.86 to 0.37 ± 0.85 respectively), these two parameters decreased in the placebo group which was significant only for WAZ (P = 0.01). Moreover, no significant association was found between mineral intake and breast milk mineral contents. It seems, synbiotic supplementation may have positive effects on breast milk mineral contents.     

A high pressure liquid chromatography-based assay for glutathione-S-transferase class distinction assay

In order to expedite the process of classification of the members of the family of glutathione-S-transferases (GSTs) high performance liquid chromatography with photodiode array detection (HPLC-PDA) was used as a means for measuring enzymatic activity. The GST chosen for the development of the HPLC-PDA technique was from equine liver (E-GST). The characterizing substrates, ethacrynic acid (EA) and bromosulfophthalein (BSP), along with previously gathered characterization data allowed for the distinction of α, μ or π-class enzymes. In an initial characterization of the previously unclassified E-GST it was determined that the enzyme was of the π-class with specific activities of 0.062, ± 0.0015 μmol min^− 1 mg^− 1 and 0.0019, ± 0.00064 μmol min^− 1 mg^− 1 for EA and BSP, respectively. Finally, the activity of the E-GST with the EA and BSP substrates, was measured by HPLC-PDA, and was found to be 0.027, ± 0.003 μmol min^− 1 mg^− 1 and 0.002, ± 0.0005 μmol min^− 1 mg^− 1, respectively. While the HPLC-PDA data do not mirror the spectrophotometric results quantitatively the overall response by the E-GST was the same. In general, the E-GSTs were shown to belong to the π-class when characterized by HPLC-PDA due to an EA specific activity greater than 0.01 μmol min^− 1 mg^− 1 and a negligible BSP activity (≤ 0.002 μmol min^− 1 mg^− 1).     

Investigation on the properties and kinetics of glucose-fed aerobic granular sludge

Aerobic granulation is a process in which suspended biomass aggregate and form discrete well-defined granules in aerobic systems. To investigate the properties and kinetics of aerobic granular sludge, aerobic granules were cultivated with glucose synthetic wastewater in a series of sequencing batch reactors (SBR). The spherical shaped granules were observed on 8th day with the mean diameter of 0.1 mm. With the organic loading rate (OLR) being increased to 4.0 g COD L⁻¹ d⁻¹, aerobic granules grew matured with spherical shape. The size of granules ranged from 1.2 to 1.8 mm, and the corresponding settling velocity of individual granule was 24.2–36.4 m h⁻¹. The oxygen utilization rate (OUR) of mature granules was 41.90 g O₂ kg MLSS⁻¹ h⁻¹, which was two times higher than that of activated sludge (18.32 g O₂ kg MLSS⁻¹ h⁻¹). The experimental data indicated that the substrate utilization and biomass growth kinetics generally followed Monod's kinetics model. The corresponding kinetic coefficients of k (maximum specific substrate utilization rate), K_s (half velocity coefficient), Y (growth yield coefficient) and K_d (decay coefficient) were determined as follows, k_c = 23.65 d⁻¹, K_c = 3367.05 mg L⁻¹, K_N = 0.038 d⁻¹, K_N = 29.65 mg L⁻¹, Y = 0.1927–0.2022 mg MMLS (mg COD)⁻¹ and K_d = 0.00845–0.0135 d⁻¹, respectively. Those properties of aerobic granules made aerobic granules system had a short setup period, high substrate utilization rate and low sludge production.     

Physiological mechanism of hypertolerance of cadmium in Kentucky bluegrass and tall fescue: Chemical forms and tissue distribution

Kentucky bluegrass (Poa pratensis) and tall fescue (Festuca arundinacea) are hypertolerant grasses to soil cadmium contamination. Little information is available on their tolerance mechanism. A sand culture and a hydroponic culture experiment were designed to investigate the Cd chemical form changes and its translocation in different tissues. The results showed that Kentucky bluegrass and tall fescue can tolerate 50–200 mg kg⁻¹ of soil Cd stresses and accumulate as high as 4275 and 2559 mg Cd kg⁻¹ DW, respectively, in their shoots without the loss of shoot biomass. Their Cd hypertolerance was correlated with an increase of the undissolved Cd phosphates in the leaves in both grass species, as determined by sequential solvent extraction procedures. The superior Cd tolerance of tall fescue to Kentucky bluegrass was associated with less Cd translocation into the stele of roots and less Cd transported to leaves. The pectate- and protein-integrated Cd forms may be involved in the symplastic translocation of Cd from cortex into stele, and this may lead the higher Cd concentrations in the stele of roots and then above ground leaves via long-distance transport in Kentucky bluegrass.     

GLP-1(32–36)amide,a novel pentapeptide cleavage product of GLP-1, modulates whole body glucose metabolism in dogs

We have previously demonstrated in human subjects who under euglycemic clamp conditions GLP-1(9–36)amide infusions inhibit endogenous glucose production without substantial insulinotropic effects. An earlier report indicates that GLP-1(9–36)amide is cleaved to a nonapeptide, GLP-1(28–36)amide and a pentapeptide GLP-1(32–36)amide (LVKGR amide). Here we study the effects of the pentapeptide on whole body glucose disposal during hyperglycemic clamp studies. Five dogs underwent indwelling catheterizations. Following recovery, the dogs underwent a 180 min hyperglycemic clamp (basal glucose +98 mg/dl) in a cross-over design. Saline or pentapeptide (30 pmol kg⁻¹ min⁻¹) was infused during the last 120 min after commencement of the hyperglycemic clamp in a primed continuous manner. During the last 30 min of the pentapeptide infusion, glucose utilization (M) significantly increased to 21.4 ± 2.9 mg kg⁻¹ min⁻¹compared to M of 14.3 ± 1.1 mg kg⁻¹ min⁻¹ during the saline infusion (P = 0.026, paired t-test; P = 0.062, Mann–Whitney U test). During this interval, no significant differences in insulin (26.6 ± 3.2 vs. 23.7 ± 2.5 μU/ml, P = NS) or glucagon secretion (34.0 ± 2.1 vs. 31.7 ± 1.8 pg/ml, P = NS) were observed. These findings demonstrate that under hyperglycemic clamp studies the pentapeptide modulates glucose metabolism by a stimulation of whole-body glucose disposal. Further, the findings suggest that the metabolic benefits previously observed during GLP-1(9–36)amide infusions in humans might be due, at least in part, to the metabolic effects of the pentapeptide that is cleaved from the pro-peptide, GLP-1(9–36)amide in the circulation.