A method for the use of landscape metrics in freshwater research and management

Freshwater research and management efforts could be greatly enhanced by a better understanding of the relationship between landscape-scale factors and water quality indicators. This is particularly true in urban areas, where land transformation impacts stream systems at a variety of scales. Despite advances in landscape quantification methods, several studies attempting to elucidate the relationship between land use/land cover (LULC) and water quality have resulted in mixed conclusions. However, these studies have largely relied on compositional landscape metrics. For urban and urbanizing watersheds in particular, the use of metrics that capture spatial pattern may further aid in distinguishing the effects of various urban growth patterns, as well as exploring the interplay between environmental and socioeconomic variables. However, to be truly useful for freshwater applications, pattern metrics must be optimized based on characteristic watershed properties and common water quality point sampling methods. Using a freely available LULC data set for the Santa Clara Basin, California, USA, we quantified landscape composition and configuration for subwatershed areas upstream of individual sampling sites, reducing the number of metrics based on: (1) sensitivity to changes in extent and (2) redundancy, as determined by a multivariate factor analysis. The first two factors, interpreted as (1) patch density and distribution and (2) patch shape and landscape subdivision, explained approximately 85% of the variation in the data set, and are highly reflective of the heterogeneous urban development pattern found in the study area. Although offering slightly less explanatory power, compositional metrics can provide important contextual information.     

Integrating Fire Risk Considerations in Forest Management Planning in Spain – A Landscape Level Perspective

It is reasonable to assume that there is a relationship between the spatial distribution of forest fuels and fire hazards. Therefore, if fire risk is to be included into numerical forest planning, the spatial distribution of risky and non-risky forest stands should be taken into account. The present study combines a stand-level fire risk model and landscape level optimization to solve forest planning problems in which the fire risk plays an important role. The key point of the method was to calculate forest level fire resistance metrics from stand level indices and use these metrics as objective variables in numerical optimization. This study shows that maximizing different landscape metrics produces very different landscape configurations with respect to the spatial arrangement of resistant and risky stands. The landscapes obtained by maximizing different metrics were tested with a fire spread simulator. These tests suggested that the mean fire resistance of the landscape, which is a non-spatial metric, is the most important factor affecting the burned area. However, spatial landscape metrics that decrease the continuity of fire resistance in the landscape can significantly improve the fire resistance of the landscape when used as additional objective variables.     

Fast-track applications: The potential for direct delivery of proteins and nucleic acids to plant cells for the discovery of gene function

In animal systems, several methods exist for the direct delivery of nucleic acids and proteins into cells for functional analysis. Until recently, these methods have not been applied to plant systems. Now, however, several preliminary reports suggest that both nucleic acids and proteins can also be delivered into plant cells by very simple, direct application. This promises to open the way for high-throughput screening for gene function in a range of plant species.     

Cell type-specific characterization of nuclear DNA contents within complex tissues and organs

Background  

Eukaryotic organisms are defined by the presence of a nucleus, which encloses the chromosomal DNA, and is characterized by its DNA content (C-value). Complex eukaryotic organisms contain organs and tissues that comprise interspersions of different cell types, within which polysomaty, endoreduplication, and cell cycle arrest is frequently observed. Little is known about the distribution of C-values across different cell types within these organs and tissues.     

Preliminary results on detection of maize treated with electrons for seed dressing and according decontamination and infestation

Saatgut und Getreide kann mit niederenergetischen Elektronen (<300 kev) oder=" hochenergetischen=" elektronen=" (1–10 mev)=" wirksam=" behandelt=" werden,=" um=" mikroorganismen=" und=" insekten=" abzutöten.=" in=" dieser=" vorläufigen=" studie=" wurde=" mais=" mit=" niederenergetischen=" (125 kev)=" und=" hochenergetischen=" elektronen=" (10 mev)=" behandelt.=" um=" diese=" elektronenbehandlung=" nachzuweisen,=" wurden=" verschiedene=" verfahren=" eingesetzt:=" photostimulierte=" lumineszenz=" (psl),=" thermolumineszenz=" (tl)=" und=" dna-kometentest.=" für=" diese=" drei=" nachweismethoden=" existieren=" bereits=" europäische=" normen=" und=" sie=" sind=" als=">Allgemeine Codex Methoden zum Nachweis bestrahlter Lebensmittel etabliert. Die Ergebnisse zeigen, dass PSL und TL geeignete Verfahren sind, um sowohl eine Behandlung von Mais mit niederenergetischen als auch mit hochenergetischen Elektronen zu erkennen. Der DNA-Kometentest erwies sich als weniger geeignet: die Behandlung mit niederenergetischen Elektronen konnte—wie erwartet—nicht nachgewiesen werden. Die Behandlung mit hochenergetischen Elektronen konnte bei einer Maissorte erkannt werden, jedoch nicht bei einer anderen Sorte.     

Maceration of plant tissue by fungi is inhibited by recombinant antipectinase antibodies

Polyclonal antiserum from mice immunized with extracellular proteins from Rhizoctonia solani inhibited pectinase and cellulase activities in cell free culture supernatants of Rhizoctonia solani. Spleen mRNA from these mice was used to construct a cDNA library from which antipectinase ScFv antibodies were isolated using phage display techniques. Soluble ScFv antibodies produced by individual clones in Escherichia coli inhibited polygalacturonase in the culture supernatants of a range of fungal pathogens, including ascomycetes, basidiomycetes, and oomycetes. The soluble antibodies also inhibited maceration of potato tissue by these pathogens.     

Epitope identification and <Emphasis Type="Italic">in silico</Emphasis> prediction of the specificity of antibodies binding to the coat proteins of <Emphasis Type="Italic">Potato Virus Y</Emphasis> strains

A phage library containing 2.7 × 10⁹ randomly expressed peptides was used to determine the epitopes of three monoclonal antibodies that bind to the coat protein of potato virus Y. Construction of the consensus sequences for the peptides obtained after three selection rounds indicated that each antibody recognized a different epitope located within the first 50 N-terminal amino acids of the coat protein. The location of the epitopes was confirmed by heterologous expression of the N-terminal part of the coat protein in Escherichia coli, and, subsequently, by performing an immunological test with the three antibodies. The accuracy of the phage library was demonstrated by predicting in silico the cross-reactivity of the three antibodies with other potyvirus family members. ELISA and in silico predictions revealed the same results in almost every case. The potential of peptide phage libraries to optimize the use of antibodies in plant virology is discussed.     

Antagonistic rhizoplane bacteria induce diverse morphological alterations in Peronosporomycete hyphae during <Emphasis Type="Italic">in vitro</Emphasis> interaction

A total of 150 bacteria were isolated from rhizoplanes of the host and non-host plants of a phytopathogenic Peronosporomycete Aphanomyces cochlioides. Upon screening, 5% of the isolates were evaluated as antagonists as they inhibited radial growth of A. cochlioides AC-5 hyphae in a dual culture assay. In addition, those antagonistic bacteria also induced characteristic morphological alterations in the A. cochlioides AC-5 hyphae that grew towards bacterial colonies. Hyphal morphological alterations observed in AC-5 and other tested strains of Peronosporomycetes included excessive branching, curly growth, unusually longer and pointed tip formation and swelling; all of these were comparable to the alterations induced by known antimicrobial compounds. Among the antagonistic bacteria, Pseudomonas sp. strain EC-S101 induced a unique branching pattern (tree-like) in AC-5 hyphae by continuous apical bifurcation of successive hyphae, where increases in number of branches and hyphal area were linearly correlated with time up to 10 h. Our observations suggested that the pathogen might have lost its ability of normal branch production; however maintained the capability of self-branching. Soluble extracts from the culture fluids of Pseudomonas sp. strain EC-S101 and Stenotrophomonas maltophilia EC-S105 induced similar excessive branching and curly growth in A. cochlioides hyphae as the respective bacterium. These results revealed that bacterial metabolites appeared to be responsible for induction of morphological alterations. Interestingly, the antagonistic bacteria that induced hyphal morphological alterations, also efficiently suppressed in vivo damping-off disease caused by AC-5. We suggest that antagonistic rhizoplane bacteria have the capability to induce diverse morphological alterations in Peronosporomycetes hyphae during in vitro interactions. Hyphal morphological alterations associated with growth inhibition and the induction of characteristic morphological changes indicate antagonistic activity against the Peronosporomycete.