Landscape geological age explains large scale spatial trends in oribatid mite diversity

Landscape Ecology - To understand the overwhelming species richness in soil the focus of attention has traditionally been on local soil conditions, such as physical and chemical characteristics....     

Animal performance and reproductive aspects of female Rhamdia quelen fed on different levels of digestible energy

This study was conducted to evaluate the effects of different diet energy levels on animal performance. Specifically, this investigation examined the reproductive and histological aspects of the liver and gonads of female silver catfish (Rhamdia quelen). These fish were fed for 210 days with diets containing 30% digestible protein (DP) and digestible energy (DE) that corresponded to 11.93, 12.98, 14.03, 15.07 and 16.12 MJ of DE kg^?1. The initial and final lengths, weights, and weight gains, the visceral, gonadal, and hepatosomatic indices, and the histological parameters hepatocytes area and gonadal stages were evaluated. In the reproductive season, the fish were submitted to an artificial reproduction protocol and the percentage of spawning females and their relative and absolute fecundity were evaluated. DE did not affect reproductive or animal performance aspects (P > 0.05). Cytoplasmic vacuoles in hepatocytes were observed in higher DE levels. Thus, female Rhamdia quelen can be fed a diet of 30% DP with 11.93 MJ of DE kg^?1 without reproductive or performance losses.     

Root-associated bacteria containing 1-aminocyclopropane-1-carboxylate deaminase improve growth and nutrient uptake by pea genotypes cultivated in cadmium supplemented soil

The effect of inoculation with Pseudomonas brassicacearum Am3, Pseudomonas marginalis Dp1 and Rhodococcus sp. Fp2 containing 1-aminocyclopropane-1-carboxylate deaminase (ACCD) on growth and uptake of N, P, K, Ca, S, Fe and Cd in shoots of pea (Pisum sativum) genotypes VIR188, VIR1658, VIR3429 and VIR4488 was studied in pot experiment with non-polluted and Cd-supplemented (10 mg Cd kg⁻¹) sod-podzolic soil. The growth-promoting effect of bacteria depended on plant genotype and bacterial strain. Only Rhodococcus sp. Fp2 had no ACCD activity in vitro in the presence of Cd and did not stimulate pea growth in Cd-supplemented soil. Inoculation with bacteria counteracted the Cd-induced inhibition of nutrient uptake by plants probably through stimulation of root growth and enhancement of nutrient uptake processes. Nutritional effects of the bacteria were specific with respect to the nutrient.     

Characterization and biological activities of humic substances from mumie

Mumie, a semihard black resin formed by long-term humification, is believed to have therapeutic properties. Although mumie has been used in folk medicine since ancient times, there is little information available concerning the physicochemical properties of its constituents and the mechanisms of its therapeutic efficacy. For this study crude mumie was fractionated into fulvic acid (FA), humic acid (HA), humin, hymatomelanic acid, and two low molecular weight fractions (LMW1 and LMW2). The FA fraction was divided into five subfractions, FA1-FA5. The mumie fractions were characterized by IR, UV-vis, and fluorescence spectroscopy. Total carbohydrate content in the fractions was analyzed using the phenol reaction method. The relative content of polar groups and nonpolar hydrocarbon fragments in the mumie fractions correlated well with solubility in an aqueous medium. Biological characterization was performed using only the FA fractions. FA1 and FA2 enhanced the production of reactive oxygen species (ROS) and nitric oxide in murine peritoneal macrophages, as determined with the use of 2',7'-dichlorofluorescin diacetate and Griess reagent, respectively. The enchancement of ROS and nitric oxide production correlated with the level of total carbohydrates in the fractions. Murine splenic lymphocytes treated with FA1 showed a dose-dependent increase in [(3)H]thymidine uptake. These findings suggest that FA derived from mumie has immunomodulatory activity.     

Photon-induced Kondo satellites in a single-electron transistor

We measure the differential conductance of a single-electron transistor (SET) irradiated with microwaves. The spin-entangled many-electron Kondo state produces a zero-bias peak in the dc differential conductance if the quantum dot in the SET contains an unpaired electron. When the photon energy hf is comparable to the energy width of the Kondo peak and to e (the charge on the electron) times the microwave voltage across the dot, satellites appear in the differential conductance shifted in voltage by +/-hf/e from the zero-bias resonance. We also observe an overall suppression of the Kondo features with increasing microwave voltage.     

Whole-genome shotgun sequencing of mitochondria from ancient hair shafts

Although the application of sequencing-by-synthesis techniques to DNA extracted from bones has revolutionized the study of ancient DNA, it has been plagued by large fractions of contaminating environmental DNA. The genetic analyses of hair shafts could be a solution: We present 10 previously unexamined Siberian mammoth (Mammuthus primigenius) mitochondrial genomes, sequenced with up to 48-fold coverage. The observed levels of damage-derived sequencing errors were lower than those observed in previously published frozen bone samples, even though one of the specimens was >50,000 14C years old and another had been stored for 200 years at room temperature. The method therefore sets the stage for molecular-genetic analysis of museum collections.     

Aphid abundance and potato virus y transmission in imidacloprid-treated potatoes

Imidacloprid is a commonly used insecticide that is highly effective in controlling insect pests of potato. The relatively high cost of imidacloprid provides commercial growers with a strong incentive to reduce field application rates. In the present study, we investigated the impact of reduced imidacloprid rates on aphid abundance and potato virus Y transmission within potato fields. Infurrow applications of imidacloprid provided better aphid control even at a reduced rate when compared to threshold-based foliar applications, but did not suppress the spread of the non-persistently transmitted potato virus Y. Virus transmission was significantly decreased in foliar-sprayed plots, possibly because foliar applications incapacitated aphid vectors probing or feeding on infected plants. Despite these generally encouraging results, we still observed 2.3 to 2.7 fold increase in virus infection at foliar-treated plots at the end of the growing season.