Characterisation of immune responses in the pea aphid, Acyrthosiphon pisum.

The innate immune system of insects provides effective defence against a range of parasites and pathogens. The pea aphid, Acyrthosiphon pisum, is a novel study system for investigating host-parasite interactions due to its complex associations with both well-characterised bacterial symbionts and a diversity of pathogens and parasites, including several important biological control agents. However, little is known about the cellular and humoral immune responses of aphids.

Non-immunological defense in an evolutionary framework.

After parasite infection, invertebrates activate immune system-based defenses such as encapsulation and the signaling pathways of the innate immune system. However, hosts are often able to defend against parasites without using these mechanisms. The non-immunological defenses, such as behaviors that prevent or combat infection, symbiont-mediated defense, and fecundity compensation, are often ignored but can be important in host-parasite dynamics.

The Tn antigen-structural simplicity and biological complexity.

Glycoproteins in animal cells contain a variety of glycan structures that are added co- and/or posttranslationally to proteins. Of over 20 different types of sugar-amino acid linkages known, the two major types are N-glycans (Asn-linked) and O-glycans (Ser/Thr-linked). An abnormal mucin-type O-glycan whose expression is associated with cancer and several human disorders is the Tn antigen.

Role of matrix metalloproteinase ZMP-2 in pathogen resistance and development in Caenorhabditis elegans.

The genome of Caenorhabditis elegans includes six homologs of matrix metalloproteinases (MMPs). The C. elegans MMP gene zmp-1 has recently been shown to be involved in anchor cell invasion during post-embryonic vulval development.

Immunity and other defenses in pea aphids, Acyrthosiphon pisum.

Background: Recent genomic analyses of arthropod defense mechanisms suggest conservation of key elements underlying responses to pathogens, parasites and stresses. At the center of pathogen-induced immune responses are signaling pathways triggered by the recognition of fungal, bacterial and viral signatures. These pathways result in the production of response molecules, such as antimicrobial peptides and lysozymes, which degrade or destroy invaders.

Generation of a natural glycan microarray using 9-fluorenylmethyl chloroformate (FmocCl) as a cleavable fluorescent tag.

Glycan microarray technology has become a successful tool for studying protein-carbohydrate interactions, but a limitation has been the laborious synthesis of glycan structures by enzymatic and chemical methods. Here we describe a new method to generate quantifiable glycan libraries from natural sources by combining widely used protease digestion of glycoproteins and Fmoc chemistry. Glycoproteins including chicken ovalbumin, bovine fetuin, and horseradish peroxidase (HRP) were digested by Pronase, protected by FmocCl, and efficiently separated by 2D-HPLC.

Different roles of related currents in fast and slow spiking of model neurons from two phyla.

Neuronal activity arises from the interplay of membrane and synaptic currents. Although many channel proteins conducting these currents are phylogenetically conserved, channels of the same type in different animals can have different voltage dependencies and dynamics. What does this mean for our ability to derive rules about the role of different types of ion channels in neuronal activity? Can results about the role of a particular channel type in a particular type of neuron be generalized to other neuron types? We compare spiking model neurons in two databases constructed by exploring the maximal conductance spaces of two models.

Quantifiable fluorescent glycan microarrays.

A glycan microarray was developed by using 2,6-diaminopyridine (DAP) as a fluorescent linker and printing of the glycan-DAP conjugates (GDAPs) on epoxy-activated glass slides. Importantly, all coupled GDAPs showed a detectable level of concentration-dependent GDAP fluorescence under blue laser excitation (495 nm) that can be used for both grid location and on-slide quantification. A glycan array including a large number of GDAP's derived from natural and commercially available free glycans was constructed and glycan interactions with various plant lectins were investigated.

Hepatic cytochrome P450 gene regulation during endotoxin-induced inflammation in nuclear receptor knockout mice.

Inflammatory agents such as lipopolysaccharide (LPS) down-regulate the hepatic expression of many cytochrome P450 (P450) mRNAs and proteins. Previous studies suggested that suppression of some P450 mRNAs could involve the regulation or modulation of the nuclear receptors peroxisome proliferator-activated receptor alpha (PPARalpha) or pregnane X receptor (PXR). To determine the involvement of these receptors in P450 down-regulation, PPARalpha knockout (KO), PXR KO, and appropriate wild-type (WT) mice were administered either saline or 1 mg/kg LPS.

Altered diacylglycerol level and metabolism in neutrophils from patients with localized juvenile periodontitis.

Diacylglycerol, a physiological activator of protein kinase C, was elevated nearly twofold in unstimulated peripheral blood neutrophils from patients with localized juvenile periodontitis compared with cells from normal individuals. These cells also showed an enhanced and prolonged elevation of diglyceride in response to N-formylmethionylleucylphenylalanine. The metabolism of a cell-permeant diacylglycerol by diglyceride kinase was significantly decreased, because of a fivefold or higher elevation in the apparent Km of cellular diglyceride kinase.