Longitudinal study of winter mortality disease in Sydney rock oysters Saccostrea glomerata.

Winter mortality (WM) is a poorly studied disease affecting Sydney rock oysters Saccostrea glomerata in estuaries in New South Wales, Australia, where it can cause significant losses. WM is more severe in oysters cultured deeper in the water column and appears linked to higher salinities. Current dogma is that WM is caused by the microcell parasite Bonamia roughleyi, but evidence linking clinical signs and histopathology to molecular data identifying bonamiasis is lacking. We conducted a longitudinal study between February and November 2010 in 2 estuaries where WM has occurred (Georges and Shoalhaven Rivers). Results from molecular testing of experimental oysters for Bonamia spp. were compared to clinical disease signs and histopathology. Available environmental data from the study sites were also collated and compared. Oyster condition declined over the study period, coinciding with decreasing water temperatures, and was inversely correlated with the presence of histological lesions. While mortalities occurred in both estuaries, only oysters from the Georges River study site showed gross clinical signs and histological changes characteristic of WM (lesions were prevalent and intralesional microcell-like structures were sometimes noted). PCR testing for Bonamia spp. revealed the presence of an organism belonging to the B. exitiosa-B. roughleyi clade in some samples; however, the very low prevalence of this organism relative to histological changes and the lack of reactivity of affected oysters in subsequent in situ hybridisation experiments led us to conclude that this Bonamia sp. is not responsible for WM. Another aetiological agent and a confluence of environmental factors are a more likely explanation for the disease.

Identification and characterisation of an ostreid herpesvirus-1 microvariant (OsHV-1 µ-var) in Crassostrea gigas (Pacific oysters) in Australia.

Between November 2010 and January 2011, triploid Crassostrea gigas (Pacific oysters) cultivated in the Georges River, New South Wales, experienced >95% mortality. Mortalities also occurred in wild diploid C. gigas in the Georges River and shortly thereafter in the adjacent Parramatta River estuary upstream from Sydney Harbour. Neighbouring Saccostrea glomerata (Sydney rock oysters) did not experience mortalities in either estuary. Surviving oysters were collected to investigate the cause of mortalities. Histologically all oysters displayed significant pathology, and molecular testing revealed a high prevalence of ostreid herpesvirus-1 (OsHV-1). Quantitative PCR indicated that many C. gigas were carrying a high viral load at the time of sampling, while the load in S. glomerata was significantly lower (p < 0.001). Subsequent in situ hybridisation experiments confirmed the presence of a herpesvirus in C. gigas but not S. glomerata tissues, suggesting that S. glomerata is not susceptible to infection with OsHV-1. Naïve sentinel triploid C. gigas placed in the Georges River estuary in January 2011 quickly became infected and experienced nearly 100% mortality within 2 wk of exposure, indicating the persistence of the virus in the environment. Phylogenetic analysis of sequences derived from the C2/C6 region of the virus revealed that the Australian strain of OsHV-1 belongs to the microvariant (µ-var) cluster, which has been associated with severe mortalities in C. gigas in other countries since 2008. Environmental data revealed that the Woolooware Bay outbreaks occurred during a time of considerable environmental disturbance, with increased water temperatures, heavy rainfall, a toxic phytoplankton bloom and the presence of a pathogenic Vibrio sp. all potentially contributing to oyster stress. This is the first confirmed report of OsHV-1 µ-var related C. gigas mortalities in Australia.

Internet cognitive testing of large samples needed in genetic research.

Quantitative and molecular genetic research requires large samples to provide adequate statistical power, but it is expensive to test large samples in person, especially when the participants are widely distributed geographically. Increasing access to inexpensive and fast Internet connections makes it possible to test large samples efficiently and economically online. Reliability and validity of Internet testing for cognitive ability have not been previously reported; these issues are especially pertinent for testing children. We developed Internet versions of reading, language, mathematics and general cognitive ability tests and investigated their reliability and validity for 10- and 12-year-old children. We tested online more than 2500 pairs of 10-year-old twins and compared their scores to similar internet-based measures administered online to a subsample of the children when they were 12 years old (> 759 pairs). Within 3 months of the online testing at 12 years, we administered standard paper and pencil versions of the reading and mathematics tests in person to 30 children (15 pairs of twins). Scores on Internet-based measures at 10 and 12 years correlated .63 on average across the two years, suggesting substantial stability and high reliability. Correlations of about .80 between Internet measures and in-person testing suggest excellent validity. In addition, the comparison of the internet-based measures to ratings from teachers based on criteria from the UK National Curriculum suggests good concurrent validity for these tests. We conclude that Internet testing can be reliable and valid for collecting cognitive test data on large samples even for children as young as 10 years.

Complex Interplay between the P-Glycoprotein Multidrug Efflux Pump and the Membrane: Its Role in Modulating Protein Function.

Multidrug resistance in cancer is linked to expression of the P-glycoprotein multidrug transporter (Pgp, ABCB1), which exports many structurally diverse compounds from cells. Substrates first partition into the bilayer and then interact with a large flexible binding pocket within the transporter's transmembrane regions. Pgp has been described as a hydrophobic vacuum cleaner or an outwardly directed drug/lipid flippase. Recent X-ray crystal structures have shed some light on the nature of the drug-binding pocket and suggested routes by which substrates can enter it from the membrane. Detergents have profound effects on Pgp function, and several appear to be substrates. Biochemical and biophysical studies in vitro, some using purified reconstituted protein, have explored the effects of the membrane environment. They have demonstrated that Pgp is involved in a complex relationship with its lipid environment, which modulates the behavior of its substrates, as well as various functions of the protein, including ATP hydrolysis, drug binding, and drug transport. Membrane lipid composition and fluidity, phospholipid headgroup and acyl chain length all influence Pgp function. Recent studies focusing on thermodynamics and kinetics have revealed some important principles governing Pgp-lipid and substrate-lipid interactions, and how these affect drug-binding and transport. In some cells, Pgp is associated with cholesterol-rich microdomains, which may modulate its functions. The relationship between Pgp and cholesterol remains an open question; however, it clearly affects several aspects of its function in addition to substrate-membrane partitioning. The action of Pgp modulators appears to depend on their membrane permeability, and membrane fluidizers and surfactants reverse drug resistance, likely via an indirect mechanism. A detailed understanding of how the membrane affects Pgp substrates and Pgp's catalytic cycle may lead to new strategies to combat clinical drug resistance.

Kinetic validation of the models for P-glycoprotein ATP hydrolysis and vanadate-induced trapping. Proposal for additional steps.

P-Glycoprotein, a member of the ATP-binding cassette (ABC) superfamily, is a multidrug transporter responsible for cellular efflux of hundreds of structurally unrelated compounds, including natural products, many clinically used drugs and anti-cancer agents. Expression of P-glycoprotein has been linked to multidrug resistance in human cancers. ABC transporters are driven by ATP hydrolysis at their two cytoplasmic nucleotide-binding domains, which interact to form a closed ATP-bound sandwich dimer. Intimate knowledge of the catalytic cycle of these proteins is clearly essential for understanding their mechanism of action. P-Glycoprotein has been proposed to hydrolyse ATP by an alternating mechanism, for which there is substantial experimental evidence, including inhibition of catalytic activity by trapping of ortho-vanadate at one nucleotide-binding domain, and the observation of an asymmetric occluded state. Despite many studies of P-glycoprotein ATPase activity over the past 20 years, no comprehensive kinetic analysis has yet been carried out, and some puzzling features of its behaviour remain unexplained. In this work, we have built several progressively more complex kinetic models, and then carried out simulations and detailed analysis, to test the validity of the proposed reaction pathway employed by P-glycoprotein for ATP hydrolysis. To establish kinetic parameters for the catalytic cycle, we made use of the large amount of published data on ATP hydrolysis by hamster P-glycoprotein, both purified and in membrane vesicles. The proposed kinetic scheme(s) include a high affinity priming reaction for binding of the first ATP molecule, and an independent pathway for ADP binding outside the main catalytic cycle. They can reproduce to varying degrees the observed behavior of the protein's ATPase activity and its inhibition by ortho-vanadate. The results provide new insights into the mode of action of P-glycoprotein, and some hypotheses about the nature of the occluded nucleotide-bound state.

Oxiuriasis tubárica como causa de dolor abdominal en estudio: reporte de un caso / Fallopian tube as a likely cause of abdomal pain in study: case report

INTRODUCCIÓN: La oxiuriasis es una parasitosis causada por Enterobius vermicularis, cuyo ciclo vital es exclusivo en humano. En chile se subestima su prevalencia, debido a su baja notificación, sin embargo es causante de múltiples entidades clínicas como trastornos del sueño, lesiones de la mucosa nasal, vulvovaginitis,salpingitis, ooforitis, enfermedad inflamatoria pélvica, e incluso peritonitis secundaria a perforación de asa intestinal infestada. PRESENTACIÓN DEL CASO: Mujer de 33 años que ingresa al servicio de urgencia del Hospital El Pino, Santiago de Chile, con manifestaciones clínicas compatibles con apendicitis aguda. Se realiza apendicectomía y como hallazgo operatorio se constata tumor de bordes mal definidos en trompa uterina derecha, interpretado como embarazo ectópico, por lo que se realiza salpingectomía unilateral. Sin embargo, en el estudio anatomopatológico posterior se diagnostica enterobiasis tubárica DISCUSIÓN: La infestación por Enterobius vermicularis es considerada endémica en nuestro país, con una prevalencia de hasta un 41por ciento, por lo que es necesario incorporarlo como diagnóstico diferencial de abdomen agudo.

INTRODUCTION: Estrongyloides is a parasitic disease caused by Enterobius vermicularis, Humans are hosts only to this parasite. In Chile, there are an underestimated prevalence due to its low notification, however, it causes many clinical entities as sleep disorder, nasal mucosal damage, vulvovaginitis, salpingitis, oophoritis, pelvic inflammatory disease and even peritonitis due to rupture of infested intestinal loop. CASE REPORT: A 33 years old admitted to the emergency department of Hospital El Pino with clinical manifestations compatible with acute appendicitis. Appendectomy was performed, operative findings suggested an ill-defined tumor in fallopian tube, interpreted as ectopic pregnancy. Then underwent unilateral salpingectomy after pathological examination fallopian tube salpingeal was diagnosed. DISCUSSION: Given the high prevalence and the fact that mimic acute appendicitis it´s a significant part of the differential diagnosis for acute abdomen.