Physical interaction between envelope glycoproteins E and M of pseudorabies virus and the major tegument protein UL49

Envelope glycoprotein M (gM) and the complex formed by glycoproteins E (gE) and I (gI) are involved in the secondary envelopment of pseudorabies virus (PrV) particles in the cytoplasm of infected cells. In the absence of the gE-gI complex and gM, envelopment is blocked and capsids surrounded by tegument proteins accumulate in the cytoplasm (A. R. Brack, J. Dijkstra, H. Granzow, B. G. Klupp, and T. C. Mettenleiter, J. Virol. 73:5364-5372, 1999). Here we demonstrate by yeast two-hybrid analyses that the cytoplasmic domains of gE and gM specifically interact with the C-terminal part of the UL49 gene product of PrV, which represents a major tegument protein and which is homologous to VP22 of herpes simplex virus type 1. However, deletion of the UL49 gene from PrV had only minor effects on viral replication, and ultrastructural analyses of infected cells confirmed that virus maturation and egress, including secondary envelopment in the cytoplasm, were not detectably affected by the absence of UL49. Moreover, the UL49 gene product was shown to be dispensable for virion localization of gE and gM, and mutants lacking either gE or gM incorporated the UL49 protein efficiently into virus particles. In contrast, a PrV mutant with deletions of gE-gI and gM failed to incorporate the UL49 protein despite apparently unaltered intracytoplasmic UL49 expression. In summary, we describe specific interactions between herpesvirus envelope and tegument proteins which may play a role in secondary envelopment during herpesvirus virion maturation.     

Renal Function in Hepatosplenic Schistosomiasis – An Assessment of Renal Tubular Disorders

Background

Renal involvement in Schistosoma mansoni infection is not well studied. The aim of this study is to investigate the occurrence of renal abnormalities in patients with hepatosplenic schistosomiasis (HSS), especially renal tubular disorders.

Methods

This is a cross-sectional study with 20 consecutive patients with HSS followed in a medical center in Maceió, Alagoas, Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl₂) after a 12-h period of water and food deprivation. The biomarker monocyte chemoattractant protein 1 (MCP-1) was quantified in urine. Fractional excretion of sodium (FE_Na+), transtubular potassium gradient (TTKG) and solute-free water reabsorption (TcH₂O) were calculated. The HSS group was compared to a group of 17 healthy volunteers.

Results

Patients'' mean age and gender were similar to controls. Urinary acidification deficit was found in 45% of HSS patients. Urinary osmolality was significantly lower in HSS patients (588±112 vs. 764±165 mOsm/kg, p = 0,001) after a 12-h period of water deprivation. TcH₂O was lower in HSS patients (0.72±0.5 vs. 1.1±0.3, p = 0.04). Urinary concentration deficit was found in 85% of HSS patients. The values of MCP-1 were higher in HSS group than in control group (122±134 vs. 40±28 pg/mg-Cr, p = 0.01) and positively correlated with the values of microalbuminuria and proteinuria.

Conclusions

HSS is associated with important kidney dysfunction. The main abnormalities found were urinary concentrating ability and incomplete distal acidification defect, demonstrating the occurrence of tubular dysfunction. There was also an increase in urinary MCP-1, which appears to be a more sensitive marker of renal damage than urinary albumin excretion rate.     

Fitness consequences of redundant cues of competition in male Drosophila melanogaster

Phenotypic plasticity can allow animals to adapt their behavior, such as their mating effort, to their social and sexual environment. However, this relies on the individual receiving accurate and reliable cues of the environmental conditions. This can be achieved via the receipt of multimodal cues, which may provide redundancy and robustness. Male Drosophila melanogaster detect presence of rivals via combinations of any two or more redundant cue components (sound, smell, and touch) and respond by extending their subsequent mating duration, which is associated with higher reproductive success. Although alternative combinations of cues of rival presence have previously been found to elicit equivalent increases in mating duration and offspring production, their redundancy in securing success under sperm competition has not previously been tested. Here, we explicitly test this by exposing male D. melanogaster to alternative combinations of rival cues, and examine reproductive success in both the presence and absence of sperm competition. The results supported previous findings of redundancy of cues in terms of behavioral responses. However, there was no evidence of reproductive benefits accrued by extending mating duration in response to rivals. The lack of identifiable fitness benefits of longer mating under these conditions, both in the presence and absence of sperm competition, contrasted with some previous results, but could be explained by (a) damage sustained from aggressive interactions with rivals leading to reduced ability to increase ejaculate investment, (b) presence of features of the social environment, such as male and female mating status, that obscured the fitness benefits of longer mating, and (c) decoupling of behavioral investment with fitness benefits.     

In vitro and in vivo evaluations of biodegradable implants for hormone replacement therapy: Effect of system design and PK-PD relationship

This investigation evaluated the feasibility of using subdermally implantable devices fabricated by nonconventional 3-dimensional printing technology for controlled delivery of ethinyl estradiol (EE₂). In vitro release kinetics of EE₂ and in vivo pharmacokinetics pharmacodynamics in ovariectomized New Zealand White rabbits were carried out to study 3 implant prototypes: implant I (single-channel EE₂ distribution in polycaprolactone polymer core), implant II (homogeneous EE₂ distribution in polycaprolactone polymer matrix), and implant III (concentration-gradient EE₂ distribution in polycaprolactone and poly(dl-lactide-co-glycolide) (50∶50 matrix). EE₂ was found to be released from all the implants in a nonlinear pattern with an order of implant III>implant II>implant I. The noncompartmental pharmacokinetic analysis of plasma EE₂ profiles in rabbits indicated a significant difference (p>.05) in C_max, t_max, and mean residence time between implant I and implants II and III, but no difference in the area under the plasma concentration time curves calculated by trapezoidal rule (AUC) among the implants. For pharmacodynamic studies, endogenous follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were observed to be suppressed following implantation of all implants, which demonstrated that a therapeutically effective dose of EE₂ had been delivered. Furthermore, the noncompartmental analysis of plasma FSH and LH profiles in rabbits showed a significant difference (p<.05) in AUC and the mean residence time between implant III and implants I and II. A good in vivo/in vitro relationship was observed between daily amounts of EE₂ released and plasma profiles of EE₂ for all implants. This relationship suggests that plasma profiles of EE₂ could be predicted from in vitro measurement of daily amount of EE₂ released Therefore, performing in vitro drug release studies may aid in the development of an EE₂ implant with the desired in vivo release rate. Published: September 21, 2001     

c-Type cytochrome-dependent formation of U(IV) nanoparticles by Shewanella oneidensis

Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability of microorganisms to effectively catalyze changes in the oxidation states of metals that in turn influence their solubility. Although microbial metal reduction has been identified as an effective means for immobilizing highly-soluble uranium(VI) complexes in situ, the biomolecular mechanisms of U(VI) reduction are not well understood. Here, we show that c-type cytochromes of a dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1, are essential for the reduction of U(VI) and formation of extracellular UO(2) nanoparticles. In particular, the outer membrane (OM) decaheme cytochrome MtrC (metal reduction), previously implicated in Mn(IV) and Fe(III) reduction, directly transferred electrons to U(VI). Additionally, deletions of mtrC and/or omcA significantly affected the in vivo U(VI) reduction rate relative to wild-type MR-1. Similar to the wild-type, the mutants accumulated UO(2) nanoparticles extracellularly to high densities in association with an extracellular polymeric substance (EPS). In wild-type cells, this UO(2)-EPS matrix exhibited glycocalyx-like properties and contained multiple elements of the OM, polysaccharide, and heme-containing proteins. Using a novel combination of methods including synchrotron-based X-ray fluorescence microscopy and high-resolution immune-electron microscopy, we demonstrate a close association of the extracellular UO(2) nanoparticles with MtrC and OmcA (outer membrane cytochrome). This is the first study to our knowledge to directly localize the OM-associated cytochromes with EPS, which contains biogenic UO(2) nanoparticles. In the environment, such association of UO(2) nanoparticles with biopolymers may exert a strong influence on subsequent behavior including susceptibility to oxidation by O(2) or transport in soils and sediments.     

Research ethics education for community-engaged research: a review and research agenda

Community engagement is increasingly becoming an integral part of research. "Community-engaged research" (CEnR) introduces new stakeholders as well as unique challenges to the protection of participants and the integrity of the research process. We--a group of representatives of CTSA-funded institutions and others who share expertise in research ethics and CEnR--have identified gaps in the literature regarding (1) ethical issues unique to CEnR; (2) the particular instructional needs of academic investigators, community research partners, and IRB members; and (3) best practices for teaching research ethics. This paper presents what we know, as well as what we still need to learn, in order to develop quality research ethics educational materials tailored to the full range of stakeholder groups in CEnR.