Plant response to heavy metals and organic pollutants in cell culture and at whole plant level

Background  Increasing awareness in the last decade concerning environmental quality had prompted research into ‘green solutions’ for soil and water remediation, progressing from laboratoryin vitro experiments to pot and field trials. In vitro cell culture experiments provide a convenient system to study basic biological processes, by which biochemical pathways, enzymatic activity and metabolites can be specifically studied. However, it is difficult to relate cell cultures, calli or even hydroponic experiments to the whole plant response to pollutant stress. In the field, plants are exposed to additional a-biotic and biotic factors, which complicate further plant response. Hence, we often see thatin vitro selected species perform poorly under soil and field conditions. Soil physical and chemical properties, plantmycorrhizal association and soil-microbial activity affect the process of contaminant degradation by plants and/or microorganisms, pointing to the importance of pot and field experiments. Objective  This paper is a joint effort of a group of scientists in COST action 837. It represents experimental work and an overview on plant response to environmental stress fromin vitro tissue culture to whole plant experiments in soil. Results  Results obtained fromin vitro plant tissue cultures and whole plant hydroponic experiments indicate the phytoremediation potential of different plant species and the biochemical mechanisms involved in plant tolerance. In pot experiments, several selected desert plant species, which accumulated heavy metal in hydroponic systems, succeeded in accumulating the heavy metal in soil conditions as well. Conclusions and Recommendations   In vitro plant tissue cultures provide a useful experimental system for the study of the mechanisms involved in the detoxification of organic and heavy metal pollutants. However, whole plant experimental systems, as well as hydroponics followed by pot and field trials, are essential when determining plant potential to remediate polluted sites. Multidisciplinary research teams can therefore increase our knowledge and promote a practical application of phytoremediation.     

Formation of aroma compounds from ribose and cysteine during the Maillard reaction

The headspace volatiles produced from a phosphate-buffered solution (pH 5) of cysteine and a 1 + 1 mixture of ribose and [(13)C(5)]ribose, heated at 95 degrees C for 4 h, were examined by headspace SPME in combination with GC-MS. MS data indicated that fragmentation of ribose did not play a significant role in the formation of the sulfur aroma compounds 2-methyl-3-furanthiol, 2-furfurylthiol, and 3-mercapto-2-pentanone in which the carbon skeleton of ribose remained intact. The methylfuran moiety of 2-methyl-3-(methylthio)furan originated from ribose, whereas the methylthio carbon atoms came partly from ribose and partly from cysteine. In 3-mercapto-2-butanone one carbon unit was split from the ribose chain. On the other hand, all carbon atoms in 3-thiophenethiol stemmed from cysteine. In another trial cysteine, 4-hydroxy-5-methyl-3(2H)-furanone and [(13)C(5)]ribose were reacted under the same conditions. The resulting 2-methyl-3-furanthiol was mainly (13)C(5)-labeled, suggesting that it stems from ribose and that 4-hydroxy-5-methyl-3(2H)-furanone is unimportant as an intermediate. Whereas 2-mercapto-3-pentanone was found unlabeled and hence originated from 4-hydroxy-5-methyl-3(2H)-furanone, its isomer 3-mercapto-2-pentanone was formed from both 4-hydroxy-5-methyl-3(2H)-furanone and ribose. A new reaction pathway from ribose via its 1,4-dideoxyosone is proposed, which explains both the formation of 2-methyl-3-furanthiol without 4-hydroxy-5-methyl-3(2H)-furanone as an intermediate and a new way to form 3-mercapto-2-pentanone.     

Diamond and pore structure observed in wood charcoal

Conclusions Various carbon structures were observed in the wood charcoal sample: the well known pyrolytic graphite layers, onion-like particles, and diamond structure. It is suggested that wood charcoal carbonized at 700°C is a complex of various carbon structures. The pore structure was observed by electron microscopy, and it is supposed that the microstructure and pores are closely related. Further study of the microstructure during the carbonization process of charcoal is necessary to better understand the characteristic functions of wood charcoal for utilizing it as a source of carbon material.A summary of this study was presented at the 51st annual meeting of the Japan Wood Research Society, Tokyo, April 2001, and the 50th annual meeting of the Society of Materials Science, Osaka, May 2001     

Impacts of wood extraction on soil: assessing rutting and soil compaction caused by skidding and forwarding by means of traditional and innovative methods

European Journal of Forest Research - Intensive forestry operations may cause soil compaction, plastic soil disturbances and rutting, which are responsible for undesirable effects on soils,...     

Effect of two extruded diets with different fish and squid meal ratio on growth,digestibility and body composition of Octopus vulgaris (Cuvier, 1797)

The present work studies the growth and body composition of 18 Octopus vulgaris (6 per treatment) fed two extruded diets, namely FMS and 3FMS, based on different fish and squid meal ratios (1:1, and 3:1 respectively). The diets are compared with a control diet based on crab (Carcinus mediterraneus) and bogue (Boops boops). The growing tests were conducted on animals placed in individual 300 L rectangular fibreglass tanks in an open seawater system, containing PVC tubes as shelters, resulting in 100% survival rate. The control group exhibited the highest specific growth rates (SGR = 2.14%BW day^?1), while values of around 0.69%BW day^?1 were achieved by octopuses fed the extruded diets. Even though the three groups of animals showed similar digestive gland indexes, the two extruded diets promoted significant differences in the muscle composition and fatness of the digestive gland. Digestibility of dry matter was not affected by the type of extruded diet, obtaining ADC values of around 88%. The results suggest that squid and fish meal can be both used in dry pelleted extruded diets, with moderate acceptance by the octopus, even though the formulation must be optimized with the aim of improving acceptability and achieve growths in the range of natural diets.     

Influence of Cultivation Conditions on the Sioxanthin Content and Antioxidative Protection Effect of a Crude Extract from the Vegetative Mycelium of Salinispora tropica

Due to their bioavailability, glycosylated carotenoids may have interesting biological effects. Sioxanthin, as a representative of this type of carotenoid, has been identified in marine actinomycetes of the genus Salinispora. This study evaluates, for the first time, the effect of cultivation temperature (T) and light intensity (LI) on the total cellular carotenoid content (TC), antioxidant activity (AA) and sioxanthin content (SX) of a crude extract (CE) from Salinispora tropica biomass in its vegetative state. Treatment-related differences in TC and SX values were statistically significantly and positively affected by T and LI, while AA was most significantly affected by T. In the S. tropica CE, TC correlated well (R² = 0.823) with SX and somewhat less with AA (R² = 0.777). A correlation between AA and SX was found to be less significant (R² = 0.731). The most significant protective effect against oxidative stress was identified in the CE extracted from S. tropica biomass grown at the highest T and LI (CE-C), as was demonstrated using LNCaP and KYSE-30 human cell lines. The CE showed no cytotoxicity against LNCaP and KYSE-30 cell lines.     

Exposure to non‐ionizing electromagnetic radiation of public risk prevention instruments threatens the quality of spermatozoids

The use of artificial insemination in cattle breeding has evolved to global extent, and insemination doses are often shipped via air transport which requires strict radiation‐based examinations. For the determination of effect of non‐ionizing radiation (NIR), to which are beings frequently exposed due to protection of airport or cultural event security, freshly ejaculated and cryopreserved bovine spermatozoa were used as experimental model. Following radiation with hand‐held metal detector in various exposition times (0, 10 s, 15, 30 and 60 min—groups FR, FR10, FR15, FR30 and FR60) the spermatozoa underwent motility and DNA fragmentation analyses. Study on cryoconserved semen treated with NIR was performed in time intervals 0, 10 s, 1 and 5 min (insemination doses radiated before cryoconservation—CB, CB10, CB1, CB5; samples radiated after freezing—CA, CA10, CA1 and CA5). Fresh semen and insemination doses radiated after cryoconservation showed significantly lower total and progressive motility. No effect on motility parameters was detected in semen extended with cryopreservative medium and radiated prior to freezing. Surprisingly, NIR showed a potential to stimulate spermatozoa velocity; however, the effect was modulated throughout the post‐thawing incubation. Based on the DNA fragmentation assay, sperm DNA stayed intact. Present study underlines the potential harm of NIR, which is frequently used in everyday life, with overall adverse impact on human and animal reproduction. Current study also points out on interesting short‐term spermatozoa stimulation induced by NIR.     

Short‐term transport of cadmium during a heavy‐rain event simulated by a dual‐continuum approach

The transport of solutes in soils, and its intensification due to preferential flow, plays crucial role when problems related to the groundwater pollution are dealt with. The objective of this study was to examine transport of cadmium (Cd) in response to an extreme rainfall event for three different soils using numerical modeling. The ^115mCd²⁺ concentration profile had been measured in the Bodiky reference site (Danubian Lowland, Slovakia) by the radioactive‐tracer technique and used for the calibration of the dual‐continuum model S1D. The Cd transport during a single rain event was predicted with the S1D model for light, medium‐heavy, and heavy soil in the same region. The Cd transport through the soil profile was simulated by the one‐dimensional dual‐permeability model, which assumes the existence of two pore domains: the soil‐matrix domain and the preferential‐flow domain. The model is based on Richards' equation for water flow and advection‐dispersion equation for solute transport. A modified batch technique enables to distinguish process of adsorption in the matrix domain and the preferential pathways. Modeling with classical single‐permeability approach and dual‐continuum approach without considering the particle‐facilitated transport led to negligible Cd penetration. The rainfall event with extremely high rainfall intensity induced deep penetration of Cd in the medium‐heavy and heavy soil, which may indicate increased vulnerability to shallow groundwater pollution for the respective sites in Danubian Lowland region. The highest Cd leaching was predicted for heavy clay soil, where the preferential particle‐facilitated transport of Cd through the soil profile was significant due to the contrasting properties of the soil‐matrix domain and the preferential‐flow domain. The results of the sensitivity analysis suggested only slight effect of the transfer rate coefficients on simulated Cd leaching.