Characterization of green zero-valent iron nanoparticles produced with tree leaf extracts

In the last decades nanotechnology has become increasingly important because it offers indisputable advantages to almost every area of expertise, including environmental remediation. In this area the synthesis of highly reactive nanomaterials (e.g. zero-valent iron nanoparticles, nZVI) is gaining the attention of the scientific community, service providers and other stakeholders. The synthesis of nZVI by the recently developed green bottom-up method is extremely promising. However, the lack of information about the characteristics of the synthetized particles hinders a wider and more extensive application. This work aims to evaluate the characteristics of nZVI synthesized through the green method using leaves from different trees. Considering the requirements of a product for environmental remediation the following characteristics were studied: size, shape, reactivity and agglomeration tendency. The mulberry and pomegranate leaf extracts produced the smallest nZVIs (5–10 nm), the peach, pear and vine leaf extracts produced the most reactive nZVIs while the ones produced with passion fruit, medlar and cherry extracts did not settle at high nZVI concentrations (931 and 266 ppm). Considering all tests, the nZVIs obtained from medlar and vine leaf extracts are the ones that could present better performances in the environmental remediation. The information gathered in this paper will be useful to choose the most appropriate leaf extracts and operational conditions for the application of the green nZVIs in environmental remediation.

Identification of mutations conferring insecticide-insensitive AChE in the cotton-melon aphid, Aphis gossypii Glover

We have identified two mutations in the ace1 gene of Aphis gossypii that are associated with insensitivity of acetylcholinesterase (AChE) to carbamate and organophosphate insecticides. The first of these, S431F (equivalent to F331 in Torpedo californica), is associated with insensitivity to the carbamate insecticide pirimicarb in a range of A. gossypii clones. The S431F mutation is also found in the peach-potato aphid, Myzus persicae (Sulzer), and a rapid RFLP diagnostic allows the identification of individuals of both aphid species with a resistant genotype. This diagnostic further revealed the presence of S431 in several other pirimicarb-susceptible aphid species. The serine at this position in the wild-type enzyme has only been reported for aphids and provides a molecular explanation of why pirimicarb has a specific aphicidal action. A less specific insensitivity to a wide range of carbamates and organophosphates is associated with a second mutation, A302S (A201 in T. californica).

Behavioural responses of the aphid parasitoid Diaeretiella rapae to volatiles from Arabidopsis thaliana induced by Myzus persicae

In response to herbivory by insects, several plant species have been shown to produce volatiles that attract the natural enemies of those herbivores. Using a Y-tube olfactometer, we investigated responses of the aphid parasitoid Diaeretiella rapae MacIntosh (Hymenoptera: Aphidiidae) to volatiles from Arabidopsis thaliana Columbia (Brassicaceae) plants that were either undamaged, infested by the peach-potato aphid, Myzus persicae Sulzer (Homoptera: Aphididae), or mechanically damaged, as well as to volatiles from just the aphid or its honeydew. In dual-choice experiments, female D. rapae given oviposition experience on A. thaliana infested with M. persicae were significantly attracted to volatiles from A. thaliana infested with M. persicae over volatiles from undamaged A. thaliana and similarly were significantly attracted to plants that had been previously infested by M. persicae, but from which the aphids were removed, over undamaged plants. Diaeretiella rapae did not respond to volatiles from M. persicae alone, their honeydew, or plants mechanically damaged with either a pin or scissors. We conclude that an interaction between the plant and the aphid induces A. thaliana to produce volatiles, which D. rapae can learn and respond to. Poor responses of D. rapae to volatiles from an A. thaliana plant that had two leaves infested with M. persicae, with the two infested leaves being removed before testing, suggested the possibility that, at this stage of infestation, the majority of volatile production induced by M. persicae may be localized to the infested tissues of the plant. We conclude that this tritrophic interaction is a suitable model system for future investigations of the biochemical pathways involved in the production of aphid-induced volatiles attractive to natural enemies.

Investigations into plant biochemical wound-response pathways involved in the production of aphid-induced plant volatiles

Feeding damage to plants by insect herbivores induces the production of plant volatiles, which are attractive to the herbivores natural enemies. Little is understood about the plant biochemical pathways involved in aphid-induced plant volatile production. The aphid parasitoid Diaeretiella rapae can detect and respond to aphid-induced volatiles produced by Arabidopsis thaliana. When given experience of those volatiles, it can learn those cues and can therefore be used as a novel biosensor to detect them. The pathways involved in aphid-induced volatile production were investigated by comparing the responses of D. rapae to volatiles from a number of different transgenic mutants of A. thaliana, mutated in their octadecanoid, ethylene or salicylic acid wound-response pathways and also from wild-type plants. Plants were either undamaged or infested by the peach-potato aphid, Myzus persicae. It is demonstrated that the octadecanoid pathway and specifically the COI1 gene are required for aphid-induced volatile production. The presence of salicylic acid is also involved in volatile production. Using this model system, in combination with A. thaliana plants with single point gene mutations, has potential for the precise dissection of biochemical pathways involved in the production of aphid-induced volatiles

Differential uptake, partitioning and transfer of Cd and Zn in the soil-pea plant-aphid system

The biomagnification of trace metals during transfer from contaminated soil to higher trophic levels may potentially result in the exposure of predatory arthropods to toxic concentrations of these elements. This study examined the transfer of Cd and Zn in a soil−plant−arthropod system grown in series of field plots that had received two annual applications of municipal biosolids with elevated levels of Cd and Zn. Results showed that biosolids amendment significantly increased the concentration of Cd in the soil and the shoots of pea plants and the concentration of Zn in the soil, pea roots, shoots, and pods. In addition, the ratio of Cd to Zn concentration showed that Zn was preferentially transferred compared to Cd through all parts of the system. As a consequence, Zn was biomagnified by the system whereas Cd was biominimized. Cd and Zn are considered to exhibit similar behaviors in biological systems. However, the Cd/Zn ratios demonstrated that in this system, Cd is much less labile in the root−shoot−pod and shoot−aphid pathways than Zn.

Effects of aphid infestation on Cd and Zn concentration in wheat

The effect of infestation by the aphid Metopolophium dirhodum on the concentration and mass partitioning of Cd and Zn was studied in wheat plants. Results show that infestation did not affect the concentration of either metal in the roots or shoots of wheat, but elevated concentrations in the ears. This appeared to result from the concentration of metal in the smaller ear mass of infested plants. Infestation did not significantly affect the mass partitioning of either metal in any part of the plant, some 10% of both metals being allocated to the roots. However, the two metals contrasted in their partitioning in the aerial parts of the plant, with ca. 60% of Cd mass partitioned in the shoots and ca. 67% of Zn mass partitioned in the ears. The possible effects of infestation on the transfer of Cd and Zn from the soil to cereal aphids are discussed.

Comparative studies of the sample decomposition of green and roasted coffee for determination of nutrients and data exploratory analysis

The contents of some nutrients in 35 Brazilian green and roasted coffee samples were determined by flame atomic absorption spectrometry (Ca, Mg, Fe, Cu, Mn, and Zn), flame atomic emission photometry (Na and K) and Kjeldahl (N) after preparing the samples by wet digestion procedures using i) a digester heating block and ii) a conventional microwave oven system with pressure and temperature control. The accuracy of the procedures was checked using three standard reference materials (National Institute of Standards and Technology, SRM 1573a Tomato Leaves, SRM 1547 Peach Leaves, SRM 1570a Trace Elements in Spinach). Analysis of data after application of t-test showed that results obtained by microwave-assisted digestion were more accurate than those obtained by block digester at 95% confidence level. Additionally to better accuracy, other favorable characteristics found were lower analytical blanks, lower reagent consumption, and shorter digestion time. Exploratory analysis of results using Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) showed that Na, K, Ca, Cu, Mg, and Fe were the principal elements to discriminate between green and roasted coffee samples. ©2007 Sociedade Brasileira de Química.

Antimicrobial activity of peach and grapevine defensins

Antimicrobial peptides (AMPs) are an important component of the innate immune system of the plants. Plant defensins are a large family of antimicrobial peptides with several interesting features, such as small dimension, high stability and broad spectrum of action. The discovery of new molecules and the study of their mechanism of action allow to consider them attractive for biotechnological applications. In this PhD thesis a defensin from Prunus persica (PpDFN1) and four novel DEFensin Like (DEFL) peptides from Vitis vinifera have been studied. In order to characterize the antimicrobial activity of these molecules, the recombinant mature peptides have been expressed in Escherichia coli and purified to homogeneity by chromatography techniques. PpDFN1 is able to inhibit the growth of B. cinerea, P. expansum and M. laxa with different intensity. The recombinant peptide is capable of membrane permeabilization as demonstrated by SYTOX green fluorescence uptake in treated mycelia. Its interaction with membranes containing sphingolipid species has been shown by artificial lipid monolayers. Furthermore, PpDFN1 displays stronger interaction with monolayers composed by lipids extracted from sensitive fungi with the highest interaction against P. expansum, the most sensitive fungi to PpDFN1 action. DEFL 13, a defensin from grapevine, resulted the strongest antibotrytis peptides. It is electrostatically attracted to the fungal membranes as shown by the antagonist effect of the cations and is able to membrane permeabilization in B. cinerea hyphae. DEFL 13 is internalized in fungal cells and leads to fungal death by activation of some signaling pathways as demonstrated by screening of a mutant collection of B. cinerea

Effects of precooling and degreening treatments on the susceptibility of peach and citrus to handling damage.

Mechanical damage to fruits results from a combination of fruit properties and of damage inflicting effects by the handling equipment. Treatments were applied to fruits which affect mechanical damage susceptibility: precooling for stone fruits and degreening to citrus fruits. Laboratory tests (compression, impact, tumbling, abrasion) and field tests (damage in the handling lines) were applied to (3) peach, (2) apricot, (2) orange and (1) lemon varieties. Hydroor-air-cooling influence positively peach and apricot firmness and cause a significant reduction in: number of bruised fruits, and size of visible bruise, when combined with a low level of loading during handling. Degreening also affects the resistance of citrus fruits to handling, when compared to green fruits.

Capability green

Tract consultants are a landscape architecture practice, founded in 1973 as an offshoot to the highly innovative, interdisciplinary design and build company Merchant Builders, and was perhaps the first truly corporate practice of this type in Australia. Founding directors Rodney Wulff and Steve Calhoun were both instrumental in establishing the undergraduate landscape architecture course at RMIT University, and bringing our Jim Sinatra, who had taught Calhoun at the University of Iowa. Wulff remained for many years the holder of the only doctorate in landscape architecture in the country. This combination of an academic, design and professional agenda was a rich one for Tract in their early days. This founding generosity and interest in the intellectual aspects of landscape architecture continues in relation to the university in a number of ways, including information ones, such as the regular employment of applicants who fail to get into the course at RMIT. In preparing them for re-applying, he has given a number of individuals a way into the profession that the university could not allow.

Village green

For a communal garden in Copenhagen, Stig L. Andersson uses grasses of varying texture and height, creating a new view or spatial experience from every angle. The idea of vegetation texture being an important constituent of planting design is pervasive. Gardening books tell aspiring designers that "colour, texture and form" are the central aspects of planting arrangements. While these elements contribute to this language, they have tended to limit the language of planting to a singular, two dimensional paradigm, where planting is designed in static elevation. This has developed from a perennial-border approach demonstrated by the early 20th century garden designer Gertrude Jekyll, where the viewer is parallel to the bed, and the planting is layered to address this view. If one were to characterise the difference between a garden design and a landscape architectural approach, the latter would seem self-conscious in its use of space, movement and vision.

Living walls - a way to green the built environment

Actions Towards Sustainable Outcomes Environmental Issues/Principal Impacts The increasing urbanisation of cities brings with it several detrimental consequences, such as: • Significant energy use for heating and cooling many more buildings has led to urban heat islands and increased greenhouse gas emissions. • Increased amount of hard surfaces, which not only contributes to higher temperatures in cities, but also to increased stormwater runoff. • Degraded air quality and noise. • Health and general well-being of people is frequently compromised, by inadequate indoor air quality. • Reduced urban biodiversity. Basic Strategies In many design situations, boundaries and constraints limit the application of cutting EDGe actions. In these circumstances, designers should at least consider the following: • Living walls are an emerging technology, and many Australian examples function more as internal feature walls. However,as understanding of the benefits and construction of living walls develops this technology could be part of an exterior facade that enhances a building’s thermal performance. • Living walls should be designed to function with an irrigation system using non-potable water. Cutting EDGe Strategies • Living walls can be part of a design strategy that effectively improves the thermal performance of a building, thereby contributing to lower energy use and greenhouse gas emissions. • Including living walls in the initial stages of design would provide greater flexibility to the design, especially of the facade, structural supports, mechanical ventilation and watering systems, thus lowering costs. • Designing a building with an early understanding of living walls can greatly reduce maintenance costs. • Including plant species and planting media that would be able to remove air impurities could contribute to improved indoor air quality, workplace productivity and well-being. Synergies and References • Living walls are a key research topic at the Centre for Subtropical Design, Queensland University of Technology: http://www.subtropicaldesign.bee.qut.edu.au • BEDP Environment Design Guide: DES 53: Roof and Facade Gardens • BEDP Environment Design Guide: GEN 4: Positive Development – Designing for Net Positive Impacts (see green scaffolding and green space frame walls). • Green Roofs Australia: www.greenroofs.wordpress.com • Green Roofs for Healthy Cities USA: www.greenroofs.org