Molecular phylogeny of the apterygotan insects based on nuclear and mitochondrial genes

Basal hexapodan orders (Apterygota) are traditionally divided in two well defined taxonomic groups, Entognatha and Ectognatha. Entognathy (the enclosed mouthparts condition) is considered the most distinctive character joining the Ellipura (Protura+ Collembola) with the order Diplura, whereas the presence of exposed mouthparts (ectognathy) is the feature shared by Microcoryphia and Zygentoma with the pterygote insects. In spite of the growing interest for the evolutionary history of the Apterygota, there is no complete agreement among the general phylogenetic hypotheses based on the study of morphological characters. In this study we analyzed the DNA sequence of segments of the nuclear Elongation Factor-1α(EF-1α) and of the mitochondrial 12S rRNA genes, and used different methods of phylogenetic reconstruction. The 12S gene seems to be more suited than the EF-1α to resolve some of the most outstanding systematic disputes, whereas the lack of resolution at the deeper nodes does not allow to assess the phylogenetic relationships within Microcoryphia and between ectognathan orders. We have obtained a fairly high support for the monophyly of the orders Diplura and Zygentoma. In the 12S analysis, the Ellipura and the Entognatha form monophyletic assemblages. In addition, the study of the distribution of introns in the EF-1α suggests a relationship between Collembola and Diplura.     

Evaluation of enrichment and plating media for isolating Listeria monocytogenes

We compared selective enrichment broths used by the U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA), Food Safety and Inspection Service, for their efficiency in the quantitative recovery of Listeria monocytogenes from a naturally contaminated Brie cheese that was obtained as part of an epidemic investigation. Quantitative recovery of Listeria in FDA broth (greater than 2.4 x 10(5) colony forming units/mL) was significantly better than recovery in USDA broth (9.3 x 10(3) colony forming units/mL). When USDA broth was supplemented with D-glucose and Phytone (papaic digest of soy protein), its recovery efficiency improved but did not equal that of FDA broth for isolating L. monocytogenes from Brie cheese. A comparison of 4 selective plating media [modified McBride's agar, gum base nalidixic acid agar, lithium chloride-phenylethanol-moxalactam agar (LPM), and acriflavine-ceftazidime agar (AC)] showed that 3 L. monocytogenes strains belonging to serotype 1/2a were partially or completely inhibited on LPM and AC agars. One strain of serotype 1/2a formed microcolonies on modified McBride's agar after 48 h of incubation.     

Conservation implications of recent advances in biodiversity–functioning research

Studies have shown that increasing diversity has a positive influence on many ecosystem functions and services, for example, biomass productivity. However, most diversity–functioning studies have derived their conclusions (1) from considering only random species assemblages, (2) from small spatial scales – often micro- and mesocosm experiments, (3) from studying merely a single trophic level, and (4) studies from a small number of biomes dominate. Critics argue that these studies provide little basis to evaluate the consequences for biodiversity loss in the real world. Here we re-consider the latest research focusing on each limitation in turn to highlight the possible lessons for real-world conservation from recent biodiversity–ecosystem function (BEF) research. Tentative general lessons from recent research include: (1) the need to urgently forestall human-induced extinction (i.e., non-random extinction) over large areas, in order to avert large negative functional consequences which may be more pronounced at larger scales and (2) preserve relatively intact communities because biotic interactions across the multi-trophic levels may have a synergistic contribution to the overall functioning of a system. However, considering the complexity of the community dynamics of natural systems, we recommend using natural systems – and understanding the basic physiological features and ecological roles of the species within them – because they implicitly include realistic extinction process, trophic structures and spatial–temporal scales as a useful way of increasing the relevance of future BEF studies to conservation.     

Phosphorus Fractionation in Sediment Cores Collected In 2005 Before and After Onset of an Aphanizomenon flos-aquae Bloom in Upper Klamath Lake, OR, USA

We tested the hypothesis that there would be measurable losses of phosphorus (P) from surficial sediments of Upper Klamath Lake (UKL), Oregon, if sediments were a source of P during an algal bloom. We compared concentrations of total and forms of P at various depths in cores collected before and after the onset of a large Aphanizomenon flos-aquae bloom. Concentrations of inorganic P were determined in extraction solutions of MgCl₂ (1 M, pH 8), citrate-dithionite-bicarbonate, and 1 M HCl. Sediments below 2 cm were dominated by residual P which is defined as total P minus inorganic P. During the study period, data from the top 2-cm of sediment indicated (a) significant decrease in total P concentration, primarily associated with iron oxyhydroxides at one site, and (b) significant increase in total P concentration associated with residual P at a second site. Data from two other sites indicated no net changes in concentrations of total P.     

Environmental effects on soil NO concentrations and root N uptake in beech and spruce forests

This study aimed to investigate the shifts in net nitrogen (N) uptake and N compounds of fine roots over the vegetation period (i.e., spring, summer, autumn) and correlate this with NO concentration in the soil. Soil NO concentration was measured using gas lysimeters for collection and a chemiluminescence analyzer for quantification. Net N uptake by the roots was determined using the ¹⁵N enrichment technique. N pools were quantified using spectrophotometric techniques. Soil NO concentrations at beech and spruce forest sites were highest in spring (June), and lowest in winter (December). Total N of the roots was similar during the seasons and between the two years under study despite considerable variation of different N compounds. Net N uptake generally increased with higher N supply. Correlation analysis revealed a positive relationship between soil NO concentration and net N uptake only for spruce trees. This relationship seemed to be modulated by environmental factors and tree species.     

Effect of gallium on photosynthetic pigments and peroxidase activity of Chlorella pyrenoidosa

Green algae (Chorella pyrenoidosa) were grown in iron‐deficient and normal iron supplied nutrient solution and treated with 1 uM gallium. Treatment with gallium enhanced the growth rate and chlorophyll content of algae cultures. Significant changes were recorded in individual photosynthetic pigment composition of treated cultures. In both iron‐deficient and normal iron supplied cultures, gallium treatment enhanced peroxidase enzyme activity. Partially purified peroxidase showed different kinetic properties in the samples treated with gallium. An iron‐gallium interaction is proposed that affects chlorophyll metabolism and peroxidase activity in green algae.     

Survey of polyphenol constituents in grapes and grape-derived products

A rapid and comprehensive qualitative method has been developed to characterize the different classes of polyphenols, such as anthocyanins, flavonols, phenolic acids, and flavanols/proanthocyanidins, in grape products. The detection was achieved by two runs with the same LC gradient in different MS ionization modes and mobile phase modifiers (positive ionization mode and 0.4% trifluoroacetic acid for anthocyanins and flavonols; negative ionization mode and 0.1% formic acid for phenolic acids and flavanols). From an analysis of the MS and UV data and in comparison with the authenticated standards, a total of 53 compounds were identified, including 33 anthocyanins, 12 flavonols, 4 phenolic acids, and 4 flavanols/proanthocyanidins. With the method developed, a survey was then conducted to qualitatively assess the composition of polyphenols among 29 different grape products including original grape, grape juice, grape wine, and grape-derived dietary supplements, and their chemical profiles were systematically compared. This method provided a comprehensive qualitative insight into the composition of polyphenols in grape-derived products.     

Vitamin D and sterol composition of 10 types of mushrooms from retail suppliers in the United States

Vitamin D(2) (ergocalciferol) and sterols were analyzed in mushrooms sampled nationwide in the United States to update the USDA Nutrient Database for Standard Reference. Vitamin D(2) was assayed using HPLC with [(3)H]-vitamin D(3) internal standard and sterols by GC-FID mass spectrometric (MS) confirmation. Vitamin D(2) was low (0.1-0.3 μg/100 g) in Agaricus bisporus (white button, crimini, portabella) and enoki, moderate in shiitake and oyster (0.4-0.7 μg/100 g), and high in morel, chanterelle, maitake (5.2-28.1 μg/100 g) and UV-treated portabella (3.4-20.9 μg/100 g), with significant variability among composites for some types. Ergosterol (mg/100 g) was highest in maitake and shiitake (79.2, 84.9) and lowest in morel and enoki (26.3, 35.5); the range was <10 mg/100 g among white button composites but 12-50 mg/100 g among samples of other types. All mushrooms contained ergosta-5,7-dienol (22,23-dihydroergosterol) (3.53-18.0 mg/100 g) and (except morel) ergosta-7-enol. Only morel contained brassicasterol (28.6 mg/100 g) and campesterol (1.23-4.54 mg/100 g) and no ergosta-7,22-dienol. MS was critical in distinguishing campesterol from ergosta-7,22-dienol.     

Reuse of effluent water—benefits and risks

There is an increasing trend to require more efficient use of water resources, both in urban and rural environments. A major mechanism that can be used to achieve greater efficiencies is the reuse of water that once would have been discarded into the environment after use. The reuse of water for agricultural irrigation is often viewed as a positive means of recycling water due to the potential large volumes of water that can be used. Recycled water can have the advantage of being a constant, reliable water source and reduces the amount of water extracted from the environment. In addition, in some cases treatment requirements may be need to be less than for water used in an urban environment due to less potential human contact. There are concerns and unknowns, however, about the impact of the quality of the recycled water, both on the crop itself and on the end users of the crops. Water quality issues that can create real or perceived problems in agriculture include nutrient and sodium concentrations, heavy metals, and the presence of contaminants such as human and animal pathogens, pharmaceuticals and endocrine disruptors. Social attitudes to the use of crops that have been irrigated with recycled waters and the resulting impact on market value of crops are also a major consideration. This paper will discuss the benefits from using different types of recycled water and outline the current knowledge and opinions relating to risks such as water quality issues.     

Effects of loci determining photoperiod sensitivity (Ppd-H1) and vernalization response (Sh2) on agronomic traits in the 'Dicktoo'×'Morex' barley mapping population

The objectives of this research were to determine the individual and interaction effects of the Ppd-H1 and Sh2 loci on agronomic traits under short- and long-photoperiod regimes. Nineteen doubled haploid (DH) lines from the ‘Dicktoo’בMorex’ mapping population, which represented the four genotypes at the Ppd-H1 and Sh2 loci, were pheno-typed in controlled environment photoperiods. Both Ppd-H1 and Sh2 had significant effects on several agronomic traits, in addition to their role in determining first node appearance and flowering time. The magnitude of these effects depended on daylight. Under long-day conditions (18 h) Ppd-H1, and under short-day conditions (12 h) Sh2 was a significant determinant of most characters. The interactions between these two loci were significant for several characters, particularly for yield components, under both long- and short-photoperiod regimes. Under the long-day treatment, Ppd-H1 influenced plant height through the determination of node number. There was an epistatic association between the two loci for both 1000-kernel weight and tillering. The combination of photoperiod insensitivity and vernalization requirement caused a significant increase in tillering. This was paralleled by a decrease in 1000-kernel weight. Under the long-day treatment, neither Ppd-H1 nor Sh2 influenced plant yield. Under short-day conditions, the combination of photoperiod insensitivity and vernalization requirement had a pronounced negative effect on plant yield.