Wageningen University and Research Centre

About: Wageningen University and Research Centre is a education organization based out in Wageningen, Netherlands. It is known for research contribution in the topics: Population & Sustainability. The organization has 23474 authors who have published 54833 publications receiving 2608897 citations.

Miscellaneous standard methods for Apis mellifera research

Abstract: SummaryA variety of methods are used in honey bee research and differ depending on the level at which the research is conducted. On an individual level, the handling of individual honey bees, including the queen, larvae and pupae are required. There are different methods for the immobilising, killing and storing as well as determining individual weight of bees. The precise timing of developmental stages is also an important aspect of sampling individuals for experiments. In order to investigate and manipulate functional processes in honey bees, e.g. memory formation and retrieval and gene expression, microinjection is often used. A method that is used by both researchers and beekeepers is the marking of queens that serves not only to help to locate her during her life, but also enables the dating of queens. Creating multiple queen colonies allows the beekeeper to maintain spare queens, increase brood production or ask questions related to reproduction. On colony level, very useful techniques are the measu...

Assessing risks of releasing exotic biological control agents of arthropod pests

Abstract: More than 5000 introductions of about 2000 species of exotic arthropod agents for control of arthropod pests in 196 countries or islands during the past 120 years rarely have resulted in negative environmental effects. Yet, risks of environmental effects caused by releases of exotics are of growing concern. Twenty countries have implemented regulations for release of biological control agents. Soon, the International Standard for Phytosanitary Measures (ISPM3) will become the standard for all biological control introductions worldwide, but this standard does not provide methods by which to assess environmental risks. This review summarizes documented nontarget effects and discusses the development and application of comprehensive and quick-scan environmental risk assessment methods.

Fluorescence lifetime standards for time and frequency domain fluorescence spectroscopy

Abstract: A series of fluorophores with single-exponential fluorescence decays in liquid solution at 20 °C were measured independently by nine laboratories using single-photon timing and multifrequency phase and modulation fluorometry instruments with lasers as excitation source. The dyes that can serve as fluorescence lifetime standards for time-domain and frequency-domain measurements are all commercially available, are photostable under the conditions of the measurements, and are soluble in solvents of spectroscopic quality (methanol, cyclohexane, water). These lifetime standards are anthracene, 9-cyanoanthracene, 9,10-diphenylanthracene, N-methylcarbazole, coumarin 153, erythrosin B, N-acetyl-l-tryptophanamide, 1,4-bis(5-phenyloxazol-2-yl)benzene, 2,5-diphenyloxazole, rhodamine B, rubrene, N-(3-sulfopropyl)acridinium, and 1,4-diphenylbenzene. At 20 °C, the fluorescence lifetimes vary from 89 ps to 31.2 ns, depending on fluorescent dye and solvent, which is a useful range for modern pico- and nanosecond time-dom...

A genetic variation map for chicken with 2.8 million single-nucleotide polymorphisms

Abstract: We describe a genetic variation map for the chicken genome containing 2.8 million single-nucleotide polymorphisms (SNPs). This map is based on a comparison of the sequences of three domestic chicken breeds (a broiler, a layer and a Chinese silkie) with that of their wild ancestor, red jungle fowl. Subsequent experiments indicate that at least 90% of the variant sites are true SNPs, and at least 70% are common SNPs that segregate in many domestic breeds. Mean nucleotide diversity is about five SNPs per kilobase for almost every possible comparison between red jungle fowl and domestic lines, between two different domestic lines, and within domestic lines--in contrast to the notion that domestic animals are highly inbred relative to their wild ancestors. In fact, most of the SNPs originated before domestication, and there is little evidence of selective sweeps for adaptive alleles on length scales greater than 100 kilobases.

The rhizosphere zoo: An overview of plant-associated communities of microorganisms, including phages, bacteria, archaea, and fungi, and of some of their structuring factors

Abstract: Rhizosphere microorganisms have two faces, like Janus the Roman god of gates and doors who symbolizes changes and transitions, from one condition to another. One face looks at the plant root, the other sees the soil. The ears and the nose sense the other gods around and the mouths are wide open, swallowing as much as they can, and as described in Chapter 11, they also are busy talking. These faces may as well represent Hygieia (the Greek god of Health and Hygiene, the prevention of sickness and the continuation of good health) and Morta (the Roman god of death) for rhizosphere microbes can be beneficial, and promote plant growth and well being (Chapter 12) or detrimental, causing plant sickness and death (Chapter 13). It can be argued that many rhizosphere microbes are “neutral”, faceless saprophytes that decompose organic materials, perform mineralization and turnover processes. While most may not directly interact with the plant, their effects on soil biotic and abiotic parameters certainly have an impact on plant growth. Maybe they are Janus’ feet, the unsung heroes of the rhizosphere. This chapter addresses some aspects of the taxonomical and functional microbial diversity of the rhizosphere. Bacteria, Archea, viruses and Fungi will be at the heart of our discussion, while other rootassociated eukaryotes are the subjects of other chapters