Purification of a herpes-like virus from abalone (Haliotis spp.) with ganglioneuritis and detection by transmission electron microscopy.

A herpes-like virus was for the first time purified from abalone diagnosed with ganglioneuritis. Pleuropedal ganglia, pedal nerve cords, head and epipodial tissue was collected and homogenized from abalone populations exhibiting high mortality and clinical signs consistent with herpes-virus like ganglioneuritis. Following ultracentrifugation by sucrose gradient prepared in sea-water, the purified virus was negatively stained and examined under a transmission electron microscope. Virus particles were observed to have an icosahedral capsid appearance surrounded by an envelope with numerous spikes on the external surface. The capsid ranged 92-109 nm in diameter and the enveloped virus was approximately 150 nm in diameter. Virus particles were found mainly at the interface of 40-50% sucrose gradients, and a few presented at the interface of 50-60% sucrose gradients. Isopycnic gradient centrifugation was performed in a potassium tartrate gradient and caesium chloride gradient, where the buoyant density of the herpes-like virus was determined to be 1.17-1.18 g/mL. The use of sea-water as the buffer in preparation of the gradient was critical in the preliminary purification of the herpes-like virus, and more efficient harvesting of the virus was achieved by sucrose and potassium tartrate gradients than caesium chloride gradient. The described method, whilst proving successful for purifying a herpes-like virus from abalone, may also be applicable to other viruses from marine animals.

Altered epithelial cell proportions in the fetal lung of glucocorticoid receptor null mice.

Glucocorticoids provide important signals for maturation of the fetal lung and antenatal glucocorticoids are used to reduce the respiratory insufficiency suffered by preterm infants. To further understand the role of glucocorticoids in fetal lung maturation, we have analyzed mice with a targeted null mutation for the glucocorticoid receptor (GR) gene, which severely retards lung development. The lungs of fetal GR-null mice have increased lung weight and DNA content, are condensed and hypercellular, with reduced septal thinning leading to a 6-fold increase in the airway to capillary diffusion distance. In fetal GR-null mice, mRNA levels of the type II epithelial cell surfactant protein genes A and C were reduced by approximately 50%. Analysis of epithelial cell types by electron microscopy revealed that the proportions of type II cells were increased by approximately 30%, whereas the proportions of type-I cells were markedly reduced (by approximately 50%). Similarly, we found a 50% reduction in mRNA levels for T1alpha and aquaporin-5, two type I cell-specific markers, and a 20% reduction in aquaporin-1 mRNA levels. This demonstrates that during murine embryonic development, receptor-mediated glucocorticoid signaling facilitates the differentiation of epithelial cells into type I cells, but is not obligatory for type II cell differentiation.

Mycobacteria, an environmental enhancer of lupus nephritis in a mouse model of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease characterized by the production of antibodies directed against self antigens. Immune complex glomerulonephritis (GN) is one of the most serious complications of this disorder and can lead to potentially fatal renal failure. The aetiology of SLE is complex and multifactorial, characterized by interacting environmental and genetic factors. Here we examine the nature of the renal pathology in mycobacteria-treated non-obese diabetic (NOD) mice, in order to assess its suitability as a model for studying the aetiopathogenesis of, and possible treatment options for, lupus nephritis (LN) in humans. Both global and segmental proliferative lesions, characterized by increased mesangial matrix and cellularity, were demonstrated on light microscopy, and lesions varied in severity from very mild mesangiopathic GN through to obliteration of capillary lumina and glomerular sclerosis. Mixed isotype immune complexes (IC) consisting of immunoglobulin G (IgG), IgM, IgA and complement C3c were detected using direct immunofluorescence. They were deposited in multiple sites within the glomeruli, as confirmed by electron microscopy. The GN seen in mycobacteria-treated NOD mice therefore strongly resembles the pathology seen in human LN, including mesangiopathic, mesangiocapillary and membranous subclasses of LN. The development of spontaneous mixed isotype IC in the glomeruli of some senescent NOD mice suggests that mycobacterial exposure is accelerating, rather than inducing, the development of GN in this model.