Retroposed new genes out of the X in Drosophila

New genes that originated by various molecular mechanisms are an essential component in understanding the evolution of genetic systems. We investigated the pattern of origin of the genes created by retroposition in Drosophila. We surveyed the whole Drosophila melanogaster genome for such new retrogenes and experimentally analyzed their functionality and evolutionary process. These retrogenes, functional as revealed by the analysis of expression, substitution, and population genetics, show a surprisingly asymmetric pattern in their origin. There is a significant excess of retrogenes that originate from the X chromosome and retropose to autosomes; new genes retroposed from autosomes are scarce. Further, we found that most of these X-derived autosomal retrogenes had evolved a testis expression pattern. These observations may be explained by natural selection favoring those new retrogenes that moved to autosomes and avoided the spermatogenesis X inactivation, and suggest the important role of genome position for the origin of new genes.     

Fractionation of Schistosoma japonicum soluble egg antigen glycoproteins by hydrophobic interaction chromatography.

We are currently studying the soluble egg antigens of Schistosoma japonicum in an attempt to determine which antigens are potent immunogens. Previously, we demonstrated by Ouchterlony immunodiffusion and inhibition of the circumoval precipitin test that the glycoprotein fraction of soluble egg antigens contains the antigens which are most immunogenic in natural infections. The soluble egg antigen glycoproteins have now been further fractionated via hydrophobic interaction chromatography on phenyl Sepharose. We found that there were at least two antigens involved in the circumoval precipitin reaction. Both the hydrophilic antigen which we call japonicum antigen glycoprotein II (JAG II) and a mixture of hydrophobic antigens (JAG III and the JAG IV complex) were capable of causing a 50% inhibition of the COP reaction around S. japonicum eggs. JAG II was not a major serological antigen of S. japonicum since it gave only a weak precipitin line upon Ouchterlony immunodiffusion analysis with pooled sera from Filipino patients with chronic S. japonicum infections. Hydrophobic interaction chromatography yielded preparations which were sufficiently pure for use in radioimmunoassays. By radioimmunoassay, the best antigens among the glycoproteins were moderately hydrophobic JAG III and the JAG IV complex. They had large amounts of antibody directed toward them in patients with schistosomiasis japonica and exhibited little reactivity with S. mansoni. The hydrophilic glycoproteins JAG I and II were poor immunogens and extensively cross-reacted with S. mansoni. This cross-reactivity means that diagnostic tests with crude soluble egg antigens would run the risk of potential false-negative results in patients with other trematode infections.     

Nondetection of the S antigen due to the presence of sodium hypochlorite

Low concentrations of sodium hypochlorite (chlorine bleach) are known to destroy S antigen on intact fresh red blood cells (RBCs). Sodium hypochlorite is commonly used as a disinfectant. We report nondetection of the S antigen in tube and microplate saline indirect antiglobulin testing (SIAT) with a lot of commercial saline utilized in our donor screening and reference laboratories. Known S+s+ RBCs were found to be nonreactive with anti-S by SIAT in our reference laboratory. Our investigation demonstrated the presence of chlorine in the commercial saline. The saline lot was used for several days of donor screening and recall of FFP and platelet concentrates was initiated. Two lots of saline were recalled from blood banks across North America.     

A tissue culture bilayer model to study the passage of Neisseria meningitidis.

A tissue culture bilayer system has been developed as a model to study the mechanisms of attachment and invasion involved in the pathogenesis of Neisseria meningitidis. The model incorporates epithelial and endothelial cell layers separated by a microporous membrane and makes it possible to observe and quantify the passage of bacteria through the multiple layers and to study the mechanisms by which they make this passage. This model is adaptable to a wide variety of microbial pathogens and can be modified by substituting any physiologically relevant eucaryotic cells for the component layers. The system's makeup of cells of human origin and its reproducibility give it advantages over animal and primary organ culture models, while the added complexity of multiple layers allowing cell-to-cell communication makes it a more realistic human tissue model than standard cell monolayers.     

股骨上端形态曲线的测量、参数化与统计分析

通过对84根完好的中国人成人股骨标本进行正位和侧位两个方向的X线摄影，得到股骨正、侧两方位的X光片。对X光片上股骨上端髓腔内侧形态进行描绘，将描绘好的图像输入计算机，由计算机进行图像预处理后提取其曲线形态数据，并将形态数据参数化，从而得到可比较的、能准确表现股骨形态的量化数据，为股骨形态的分类分析和系列型人工髋关节的参数设计打下基础。     

Inactivation of the pseudorabies virus by dithiothreitol

The virucidal nature of reduced dithiothreitol (DTT) for the pseudorabies (PR) virus (PRV) is presented. The rate of decay of PRV in DTT increased exponentially as the pH rose from 6.5 to 8. Effective virucidal concentrations of DTT decreased in concentration as the pH was elevated. The reaction rate was temperature dependent under mild alkaline conditions, being essentially nil at 0° and at 20°, but progressively more rapid from 30° to 41°. Electron micrographs indicated substantial disruption of the architecture of the DTT inactivated virions.     

Rapid non-genomic inhibitory effects of glucocorticoids on human neutrophil degranulation

Background: Glucocorticoids acting as anti-inflammatory or immunosuppressive drugs have been shown to exert most of their effects genomically. Recent findings suggest that non-genomic activity might be relatively more important in mediating the therapeutic effects of high-dose pulsed glucocorticoid. However, few non-genomic anti-inflammatory effects were reported, much less non-genomic mechanisms.Objective: This study was performed to investigate the nongenomic effects of glucocorticoids on human neutrophil degranulation.Methods: Purified human neutrophils were pretreated with 6 -methylprednisolone or hydrocortisone for 5 min, and then primed with N-formyl-methionyl-leucyl-phenylalanine (fMLP) (10^–6 M) or phorbol myristate acetate (PMA) (50 ng/ml) in the presence of cytochalasin B. The release of two markers of neutrophil granules, lactoferrin and myeloperoxidase, was measured by ELISA and enzymology methods respectively.Results: Both 6 -methylprednisolone (10^–5–10^–4 M) and hydrocortisone (10^–4 M) showed significant inhibitory effects on neutrophil degranulation within 5 min after fMLP administration. For PMA stimulated degranulation, 6 -methylprednisolone (10^–4 M) showed significant inhibitory effects (p < 0.01), while hydrocortisone (10^–4 M) only showed an inhibitory tendency (P > 0.05). Neither RU486 (10^–5 M) nor cycloheximide (10^–4 M) could alter the inhibitory effects of glucocorticoids.Conclusion: Our results demonstrate that megadoses of glucocorticoids exert rapid inhibitory effects on human neutrophil degranulation at the cellular level via a new mechanism that is independent of corticosteroid type II receptor occupation or protein synthesis. We infer that these effects may be very important when glucocorticoids act as anti-inflammatory drugs during pulse therapy.Received 20 May 2004; returned for revision 21 July 2004; accepted by M.J. Parnham 23 September 2004L. Liu and Y. X. Wang contributed equally to this work.     

Infection of immunodeficient horses with Sarcocystis neurona does not result in neurologic disease

Equine protozoal myeloencephalitis is a progressive neurologic disease of horses most commonly caused by infection with the apicomplexan parasite Sarcocystis neurona. Factors affecting neuroinvasion and neurovirulence have not been determined. We investigated the pathogenesis of infection with S. neurona in horses with severe combined immune deficiency (SCID). Two immunocompetent (IC) Arabian horses and two Arabian horses with SCID were infected orally with 5 x 10(5) sporocysts of S. neurona. Four IC horses and one SCID horse were infected intravenously (i.v.) with 5 x 10(8) merozoites of the WSU-1 isolate of S. neurona. Despite prolonged parasitemia and persistent infection of visceral tissues (skeletal muscle, cardiac muscle, lung, liver, and spleen) as demonstrated by PCR and culture, SCID horses did not develop neurologic signs after oral or i.v. infection. S. neurona was undetectable in the neuronal tissues of SCID horses by either PCR, immunohistochemistry, or culture. In contrast, although parasitemia was undetectable in orally infected IC horses and of only short duration in i.v. infected IC horses, four of six IC horses developed neurologic signs. S. neurona was detectable by PCR and/or culture of neural tissue but not visceral tissue of IC horses with neurologic disease. Infected SCID horses are unable to clear S. neurona from visceral tissues, but the infection does not result in neurologic signs; in contrast, IC horses rapidly control parasitemia and infection of visceral tissues but frequently experience neuroinvasion and exhibit clinical signs of neurologic disease.