Induced hyperlipaemia and immune challenge in locusts

Injections of immunogens, such as β-1,3-glucan or lipopolysaccharide (LPS), bring about a marked hyperlipaemia with associated changes in lipophorins and apolipophorin-III in the haemolymph of Locusta migratoria. These changes are similar to those observed after injection of adipokinetic hormone (AKH). The possibility that endogenous AKH is released as part of the response to these immunogens is investigated using passive immunisation against AKH-I, and measurement of AKH-I titre in the haemolymph after injection of immunogens. The data presented show that, despite the similarity of the changes brought about by the presence of immunogens in the haemolymph to those brought about by AKH, there is no release of endogenous AKH after injection of laminarin or LPS. A direct effect of the immunogens on release of neutral lipids by the fat body cannot be demonstrated in vitro, and the mechanism by which hyperlipaemia is induced during immune challenge remains uncertain

Hypomethylation of HOXA4 promoter is common in Silver-Russell syndrome and growth restriction and associates with stature in healthy children

Silver-Russell syndrome (SRS) is a growth retardation syndrome in which loss of methylation on chromosome 11p15 (11p15 LOM) and maternal uniparental disomy for chromosome 7 [UPD(7) mat] explain 20-60% and 10% of the syndrome, respectively. To search for a molecular cause for the remaining SRS cases, and to find a possible common epigenetic change, we studied DNA methylation pattern of more than 450 000 CpG sites in 44 SRS patients. Common to all three SRS subgroups, we found a hypomethylated region at the promoter region of HOXA4 in 55% of the patients. We then tested 39 patients with severe growth restriction of unknown etiology, and found hypomethylation of HOXA4 in 44% of the patients. Finally, we found that methylation at multiple CpG sites in the HOXA4 promoter region was associated with height in a cohort of 227 healthy children, suggesting that HOXA4 may play a role in regulating human growth by epigenetic mechanisms.Peer reviewe

Genotoxic damage in polychaetes: a study of species and cell-type sensitivities.

addresses: School of Biosciences, Hatherley Laboratories, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK. [email protected]: Journal Article; Research Support, Non-U.S. Gov'tCopyright © 2008 Elsevier. NOTICE: This is the author’s version of a work accepted for publication by Elsevier. Changes resulting from the publishing process, including peer review, editing, corrections, structural formatting and other quality control mechanisms, may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mutation Research - Genetic Toxicology and Environmental Mutagenesis, 2008, Vol. 654, Issue 1, pp. 69 – 75 DOI: http://dx.doi.org/10.1016/j.mrgentox.2008.05.008The marine environment is becoming increasingly contaminated by environmental pollutants with the potential to damage DNA, with marine sediments acting as a sink for many of these contaminants. Understanding genotoxic responses in sediment-dwelling marine organisms, such as polychaetes, is therefore of increasing importance. This study is an exploration of species-specific and cell-specific differences in cell sensitivities to DNA-damaging agents in polychaete worms, aimed at increasing fundamental knowledge of their responses to genotoxic damage. The sensitivities of coelomocytes from three polychaetes species of high ecological relevance, i.e. the lugworm Arenicola marina, the harbour ragworm Nereis diversicolor and the king ragworm Nereis virens to genotoxic damage are compared, and differences in sensitivities of their different coelomic cell types determined by use of the comet assay. A. marina was found to be the most sensitive to genotoxic damage induced by the direct-acting mutagen methyl methanesulfonate (MMS), and showed dose-dependent responses to MMS and the polycyclic aromatic hydrocarbon benzo(a)pyrene. Significant differences in sensitivity were also measured for the different types of coelomocyte. Eleocytes were more sensitive to induction of DNA damage than amoebocytes in both N. virens and N. diversicolor. Spermatozoa from A. marina showed significant DNA damage following in vitro exposure to MMS, but were less sensitive to DNA damage than coelomocytes. This investigation has clearly demonstrated that different cell types within the same species and different species within the polychaetes show significantly different responses to genotoxic insult. These findings are discussed in terms of the relationship between cell function and sensitivity and their implications for the use of polychaetes in environmental genotoxicity studies

Hemocyte-lineage marker proteins in a crustacean, the freshwater crayfish, Pacifastacus leniusculus

To identify proteins associated with development of different hemocyte types in the freshwater crayfish Pacifastacus leniusculus, 2-DE followed by MS analysis was carried out with hematopoietic tissue (Hpt) cells, semigranular cells (SGC) and granular cells (GC). Within the hemocyte lineages one two-domain Kazal proteinase inhibitor (KPI) was found to be specific,for SGC, while a superoxide dismutase (SOD) was specific for GC at protein as well as at mRNA level. The proliferation cell nuclear antigen (PCNA) was detected at the mRNA level in Hpt cells only. We also provide evidence that SGC and GC most likely differentiate to maturation as separate lineages. We found that after laminarin or lipopolysaccharide (LPS) injection into crayfish, the transcript levels of PCNA and SOD increased in the Hpt cells, whereas the KPI transcript never was present in Hpt regardless of any challenge. RNA interference of PCNA in the Hpt cells led to that most of the cells did not spread or attach to the tissue culture dish. These results suggest that PCNA, KPI and SOD can be used as markers for Hpt cells, SGC and GC, respectively, and in conjunction with these results, a model is proposed how the Hpt responds to a microbial challenge by proliferation and release of Hpt cells

A shared mechanism of defense against predators and parasites: chitin regulation and its implications for life-history theory

Defenses against predators and parasites offer excellent illustrations of adaptive phenotypic plasticity. Despite vast knowledge about such induced defenses, they have been studied largely in isolation, which is surprising, given that predation and parasitism are ubiquitous and act simultaneously in the wild. This raises the possibility that victims must trade-off responses to predation versus parasitism. Here, we propose that arthropod responses to predators and parasites will commonly be based on the endocrine regulation of chitin synthesis and degradation. The proposal is compelling because many inducible defenses are centered on temporal or spatial modifications of chitin-rich structures. Moreover, we show how the chitin synthesis pathway ends in a split to carapace or gut chitin, and how this form of molecular regulation can be incorporated into theory on life-history trade-offs, specifically the Y-model. Our hypothesis thus spans several biological scales to address advice from Stearns that “Endocrine mechanisms may prove to be only the tip of an iceberg of physiological mechanisms that modulate the expression of genetic covariance”

Histone H2A as a transfection agent in crayfish hematopoietic tissue cells

We report a novel and highly efficient dsRNA transfection system based on one of the nuclear proteins, namely, histone H2A. RT-PCR semi-quantitative analysis of silencing target gene shows that the transfection efficiency of histone H2A is higher than Effectene or liposome-based transfection systems. Importantly, the high efficiency of histone H2A was associated with very low toxicity to the transfected crayfish hematopoietic tissue (Hpt) cells. The non-toxicity, effectiveness and specificity of histone H2A as a transfection agent provides a cheap, simple, highly efficient and reproducible gene delivery system, particularly for the sensitive cell cultures of crustacean animals such as crayfish and shrimp. (c) 2006 Elsevier Ltd. All rights reserved

Differential DNA Methylation in Purified Human Blood Cells: Implications for Cell Lineage and Studies on Disease Susceptibility

WOS:000306806600056Peer reviewe

Centrosomal Localization of the Psoriasis Candidate Gene Product, CCHCR1, Supports a Role in Cytoskeletal Organization

Peer reviewe