Design, synthesis and antimalarial/anticancer evaluation of spermidine linked artemisinin conjugates designed to exploit polyamine transporters in Plasmodium falciparum and HL-60 cancer cell lines.

A series of artemisinin-spermidine conjugates designed to utilise the upregulated polyamine transporter found in cancer cells have been prepared. These conjugates were evaluated against human promyelocytic leukaemia HL-60 cells and chloroquine-sensitive 3D7 Plasmodium falciparum and several show promising anticancer and antimalarial activity. Although some limitations in this vector-based approach are apparent, a number of high potency Boc-protected analogues were identified with activity against malaria parasites as low as 0.

The genome of pseudocowpoxvirus: comparison of a reindeer isolate and a reference strain.

Parapoxviruses (PPV), of the family Poxviridae, cause a pustular cutaneous disease in sheep and goats (orf virus, ORFV) and cattle (pseudocowpoxvirus, PCPV and bovine papular stomatitis virus, BPSV). Here, we present the first genomic sequence of a reference strain of PCPV (VR634) along with the genomic sequence of a PPV (F00.120R) isolated in Finland from reindeer (Rangifer tarandus tarandus).

Inhibition of glycogen synthase kinase 3beta (GSK3beta) decreases inflammatory responses in brain endothelial cells.

Immune mediators and leukocyte engagement of brain microvascular endothelial cells (BMVECs) contribute to blood-brain barrier impairment during neuroinflammation. Glycogen synthase kinase 3beta (GSK3beta) was recently identified as a potent regulator of immune responses in in vitro systems and animal models. However, the role of GSK3beta in regulation of immune endothelial functions remains undetermined.

The chemokine-binding protein encoded by the poxvirus orf virus inhibits recruitment of dendritic cells to sites of skin inflammation and migration to peripheral lymph nodes.

Orf virus (ORFV) is a zoonotic parapoxvirus that induces acute pustular skin lesions in sheep and humans. ORFV can reinfect its host and the discovery of several secreted immune modulatory factors that include a chemokine-binding protein (CBP) may explain this phenomenon. Dendritic cells (DC) are professional antigen presenting cells that induce adaptive immunity and their recruitment to sites of infection in skin and migration to peripheral lymph nodes is critically dependent on inflammatory and constitutive chemokine gradients respectively.

Peripheral modulation of worker bee responses to queen mandibular pheromone.

It is generally accepted that young worker bees (Apis mellifera L.) are highly attracted to queen mandibular pheromone (QMP). Our results challenge this widely held view.

A seven-year retrospective analysis of students entering medicine via a Rural Student Recruitment program in Western Australia.

Objective: This research aimed to evaluate the effectiveness of the Rural Student Recruitment (RSR) program. This program was an initiative to address the low number of rural students enrolled in medicine at the University of Western Australia. RSR identifies students throughout rural and remote areas of Australia interested in pursuing a career in medicine.

Cell cycle deregulation by a poxvirus partial mimic of anaphase-promoting complex subunit 11.

The anaphase-promoting complex (APC), or cyclosome, is a ubiquitin ligase with major roles in cell cycle regulation. It is required for mitotic exit, but must be deactivated for the G(1)/S phase transition to occur. APC consists of at least 12 subunits with the catalytic core formed by a scaffold protein, APC2, and a RING-H2 protein, APC11.

The orf virus inhibitor of apoptosis functions in a Bcl-2-like manner, binding and neutralizing a set of BH3-only proteins and active Bax.

We have previously shown that the Orf virus protein, ORFV125, is a potent inhibitor of the mitochondrial pathway of apoptosis and displays rudimentary sequence similarities to cellular anti-apoptotic Bcl-2 proteins. Here we investigate the proposal that ORFV125 acts in a Bcl-2-like manner to inhibit apoptosis. We show that the viral protein interacted with a range of BH3-only proteins (Bik, Puma, DP5, Noxa and all 3 isoforms of Bim) and neutralized their pro-apoptotic activity.

Evaluation of a breastfeeding assessment score in a diverse population.

A previous study performed in a predominately suburban population developed a breastfeeding assessment score (BAS) that was designed to predict, prior to hospital discharge, those mothers who would discontinue breastfeeding within the first 10 days of age. The purpose of the present study was to assess the BAS in a more diverse population. Patients were solicited from 3 urban hospitals serving patients primarily supported by public funding.

Mechanism-based bioanalysis and biomarkers for hepatic chemical stress.

Adverse drug reactions, in particular drug-induced hepatotoxicity, represent a major challenge for clinicians and an impediment to safe drug development. Novel blood or urinary biomarkers of chemically-induced hepatic stress also hold great potential to provide information about pathways leading to cell death within tissues. The earlier pre-clinical identification of potential hepatotoxins and non-invasive diagnosis of susceptible patients, prior to overt liver disease is an important goal.

Dopamine receptor activation by honey bee queen pheromone.

Queen mandibular pheromone (QMP) is produced by honey bee queens and used to regulate the behavior and physiology of their nestmates. QMP has recently been shown to block aversive learning in young worker bees, an effect that can be mimicked by treating bees with one of QMP's key components, homovanillyl alcohol (HVA). Although the mechanisms underlying this blockade remain unclear, HVA has been found to lower brain dopamine levels and to alter intracellular levels of cAMP in brain centers involved in learning and memory.

Functional and toxicological consequences of metabolic bioactivation of methapyrilene via thiophene S-oxidation: Induction of cell defence, apoptosis and hepatic necrosis.

Unlabelled: Methapyrilene, [N,N-dimethyl-N'-pyridyl-N'(2-thienylmethyl)-1,2-ethanediamine] (MP) was withdrawn from, clinical use due to reported periportal hepatic necrosis and hepatocarcinogenicity in the rat, via S-oxidation of the thiophene group. In this study MP is used as a model hepatotoxin to further characterise the functional consequences of S-oxidation of the thiophene group in vivo, in rat models and in vitro, in freshly isolated rat hepatocyte suspensions. In vivo histological studies revealed the early depletion of glutathione (GSH), which was confined to the damaged periportal area, in contrast to an increase in GSH levels in the centrilobular region.

In vivo modification of native carrier protein domains.

Carrier proteins are central to the biosynthesis of primary and secondary metabolites in all organisms. Here we describe metabolic labeling and manipulation of native acyl carrier proteins in both type I and II fatty acid synthases. By utilizing natural promiscuity in the CoA biosynthetic pathway in combination with synthetic pantetheine analogues, we demonstrate metabolic labeling of endogenous carrier proteins with reporter tags in Gram-positive and Gram-negative bacteria and in a human carcinoma cell line.

Conservation and variation of the parapoxvirus GM-CSF-inhibitory factor (GIF) proteins.

The GIF protein of orf virus (ORFV) binds and inhibits the ovine cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2). An equivalent protein has so far not been found in any of the other poxvirus genera and we therefore investigated whether it was conserved in the parapoxviruses. The corresponding genes from both the bovine-specific pseudocowpox virus (PCPV) and bovine papular stomatitis virus (BPSV) were cloned and sequenced.

Orf virus-encoded chemokine-binding protein is a potent inhibitor of inflammatory monocyte recruitment in a mouse skin model.

The parapoxvirus orf virus causes pustular dermatitis in sheep and is transmissible to humans. The virus encodes a secreted chemokine-binding protein (CBP). We examined the ability of this protein to inhibit migration of murine monocytes in response to CC inflammatory chemokines, using chemotaxis assays, and its effects on monocyte recruitment into the skin, using a mouse model in which inflammation was induced with bacterial lipopolysaccharide.

A truncated two-alpha-helix F-box present in poxvirus ankyrin-repeat proteins is sufficient for binding the SCF1 ubiquitin ligase complex.

Poxviruses encode a large family of ankyrin-repeat (ANK) proteins, most of which contain an F-box-like motif necessary for the interaction of the ANK proteins with SCF1 (Skp1-Cullin1-F-box) complexes. The viral motif is generally truncated compared with the three-alpha-helix cellular F-box. Cellular F-box alpha-helices 1-3 and regions C-terminal to them have been shown to contribute to Skp1 binding.

Antitumour and antimalarial activity of artemisinin-acridine hybrids.

Artemisinin-acridine hybrids were prepared and evaluated for their in vitro activity against tumour cell lines and a chloroquine sensitive strain of Plasmodium falciparum. They showed a 2-4-fold increase in activity against HL60, MDA-MB-231 and MCF-7 cells in comparison with dihydroartemisinin (DHA) and moderate antimalarial activity. Strong evidence that the compounds induce apoptosis in HL60 cells was obtained by flow cytometry, which indicated accumulation of cells in the G1 phase of the cell cycle.

Investigation of orf virus structure and morphogenesis using recombinants expressing FLAG-tagged envelope structural proteins: evidence for wrapped virus particles and egress from infected cells.

Orf virus (ORFV) is the type species of the genus Parapoxvirus, but little is known about the structure or morphogenesis of the virus. In contrast, the structure and morphogenesis of vaccinia virus (VACV) has been extensively studied. VACV has two main infectious forms, mature virion (MV) and extracellular virion (EV).

Poxvirus host range protein CP77 contains an F-box-like domain that is necessary to suppress NF-kappaB activation by tumor necrosis factor alpha but is independent of its host range function.

Tumor necrosis factor alpha (TNF-alpha) activates the nuclear factor kappaB (NF-kappaB) signaling pathway that regulates expression of many cellular factors playing important roles in innate immune responses and inflammation in infected hosts. Poxviruses employ many strategies to inhibit NF-kappaB activation in cells. In this report, we describe a poxvirus host range protein, CP77, which blocked NF-kappaB activation by TNF-alpha.

The role of bioactivation in the pharmacology and toxicology of the artemisinin-based antimalarials.

Artemisinin and artemisinin-based antimalarials are currently recommended as the frontline antimalarial treatment, with over 100 million courses administered annually. Despite possessing excellent therapeutic activity and tolerability, neurotoxicity and embryotoxicity have been reported in cross-species animal models. The endoperoxide group contained within the artemisinins is essential for pharmacologic and toxicological activity and it is hypothesized that its bioactivation to toxic C-centered radical species is the mechanistic basis for activity.

Nerve Terminal GABAA Receptors Activate Ca2+/Calmodulin-dependent Signaling to Inhibit Voltage-gated Ca2+ Influx and Glutamate Release.

gamma-Aminobutyric acid type A (GABA(A)) receptors, a family of Cl(-)-permeable ion channels, mediate fast synaptic inhibition as postsynaptically enriched receptors for gamma-aminobutyric acid at GABAergic synapses. Here we describe an alternative type of inhibition mediated by GABA(A) receptors present on neocortical glutamatergic nerve terminals and examine the underlying signaling mechanism(s). By monitoring the activity of the presynaptic CaM kinase II/synapsin I signaling pathway in isolated nerve terminals, we demonstrate that GABA(A) receptor activation correlated with an increase in basal intraterminal [Ca(2+)](i).

Synthesis and biological evaluation of extraordinarily potent C-10 carba artemisinin dimers against P. falciparum malaria parasites and HL-60 cancer cells.

A series of artemisinin dimers incorporating a metabolically stable C-10 carba-linkage have been prepared, several of which show remarkable in vitro antimalarial activity (as low as 30 pM) versus Plasmodium falciparum and in vitro anticancer activity in the micromolar to nanomolar range versus HL-60 cell lines.

Antibiotic evaluation and in vivo analysis of alkynyl Coenzyme A antimetabolites in Escherichia coli.

Pantothenamides have been the subject of much study as potential inhibitors of CoA and carrier protein dependent biosynthetic pathways. Based on an initial observation of growth inhibition in Escherichia coli by 3, we have synthesized a small panel of pantetheine analogues and re-examined the inhibitory properties of this class of antibiotics with an emphasis on understanding the ability of these compounds to act as substrates of native CoA and carrier protein utilizing biosynthetic pathways. Our findings suggest that a secondary structure-activity relationship is an important factor in the antibiotic activity of these compounds.