Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and huanglongbing disease do not exist in the Stapleton Station area of the Northern Territory of Australia

Abstract  A series of specimens of the Asian citrus psyllid, Diaphorina citri , collected from the Northern Territory (NT) in 1915 was recently rediscovered in the Natural History Museum, London. Surveys were conducted in 2002 on suitable hosts in the locality of the 1915 collections to see if the infestation had persisted. These failed to detect either D. citri or the bacterium that it transmits and that causes huanglongbing disease in citrus. It is presumed that D. citri was eradicated fortuitously by the removal of all citrus plants above latitude 19°S during an eradication program for citrus canker in the NT from 1916 until 1922.     

Nucleotide excision repair endonuclease genes in Drosophila melanogaster

Nucleotide excision repair (NER) is the primary pathway for the removal of ultraviolet light-induced damage and bulky adducts from DNA in eukaryotes. During NER, the helix is unwound around the damaged site, and incisions are made on the 5' and 3' sides, to release an oligonucleotide carrying the lesion. Repair synthesis can then proceed, using the intact strand as a template. The incisions flanking the lesion are catalyzed by different structure-specific endonucleases. The 5' incision is made by a heterodimer of XPF and ERCC1 (Rad1p-Rad10p in Saccharomyces cerevisiae), and the 3' incision is made by XPG (Rad2p in S. cerevisiae). We previously showed that the Drosophila XPF homologue is encoded by the meiotic recombination gene mei-9. We report here the identification of the genes encoding the XPG and ERCC1 homologues (XPG(Dm) and ERCC1(Dm)). XPG(Dm) is encoded by the mus201 gene; we found frameshift mutations predicted to produce truncated XPG(Dm) proteins in each of two mus201 alleles. These mutations cause defects in nucleotide excision repair and hypersensitivity to alkylating agents and ultraviolet light, but do not cause hypersensitivity to ionizing radiation and do not impair viability or fertility. ERCC1(Dm) interacts strongly in a yeast two-hybrid assay with MEI-9, indicative of the presumed requirement for these polypeptides to dimerize to form the functional endonuclease. The Drosophila Ercc1 gene maps to polytene region 51D1-2. The nucleotide excision repair gene mus210 maps nearby (51E-F) but is distinct from Ercc1.     

Role of metal ions in Escherichia coli alkaline phosphatase. A study of the metal-water interaction by nuclear relaxation rate measurements on water protons.

The binding of metal to alkaline phosphatase from Escherichia coli and the binding of water and orthophosphate to the Me-2+-enzyme binary complex have been examined by water proton relaxation rate (PRR) measurements. Titration of the three paramagnetic metals, Mn2+, Cu2+, and Co2+, into apoalkaline phosphatase and the titrations of apoenzyme into metal have been carried out. Analysis of the spin-lattice relaxation rates for these titrations and of Scatchard binding curves derived from these results, as well as EPR data, show four tight manganese sites, between two and three tight copper sites, or four cobalt sites per enzyme dimer of molecular weight 80,000. The multiple sites for each metal are indistinguishable by these magnetic resonance techniques. Both the spin-lattice- and spin-spin-relaxation rates exhibit a negative temperature coefficient, showing that these processes are not exchange-limited. From a frequency dependence study of T-1 and from the T-1:T-2 ratio measured at 220 MHz, correlation times from the water-enzyme complexes have been estimated. For H20-Mn-2+-alkaline phosphatase, gamma c equals 1.55 times 10-9 s; for H20-Cu-2+ -alkaline phosphatase, gamma c equals 1.82 times 10-s; and for the cobalt complex, gamma c equals 1.0 times 10-12 s at 4 degrees. Assuming 1 water molecule bound per metal site, these correlation times correspond to the following water-metal distances: gamma (A) is 4.0 A for Mn-2+-H20, 3.4 A for Cu-2+-H20, and 2.8 A for Co-2+-H20. Thus, water is shown to bind directly to the metal atoms of alkaline phosphatase. The correlation between the length of the water-metal bond and the relative activity of the various metalloenzymes support the importance of this binding in the monophosphoesterase reaction catalyzed by alkaline phosphatase. Addition of excess orthophosphate to any of the water-metalloenzyme complexes does not displace an exchangeable water molecule from the metal site. The Mn-PO-4 distance which we have reported earlier (Zukin, R.S., Hollis, D.P., and Gray, G.A. (1973) Biochem. Biophys. Res. Commun. 53, 238) to be 7.3 A is consistent with this finding and suggests a model in which Pi binds to Mn-2+-alkaline phosphatase through a water bridge.     

Uptake and metabolism of prostaglandins by isolated perfused lung: Species comparison and the role of plasma protein binding

We have investigated the uptake and subsequent metabolism of the prostaglandins (PGs) PGE₁, PGA₁, and PGB₁ by rat, guinea pig and rabbit isolated perfused lungs (IPL). Significant species differences were not observed in the uptake or metabolism of any PG on passage through the IPL. However, differences in the uptake of PGA₁ and PGB₁ and in the metabolism of PGA₁ were observed with a given species when the composition of the perfusion medium was varied. The IPL removed minimal amounts (<20% of the supply rate) of PGA₁ and PGB₁ from the circulation when the perfusate contained 4.5% bovine serum albumin (BSA). In the absence of BSA, however, both PGA₁ and PGB₁ were substantially removed from circulation (～53% of the supply rate) and PGA₁ was also metabolized. The composition of the perfusate had no effect on the uptake and metabolism of PGE₁ which was always taken up and metabolized to a greater extent than was PGA₁ and PGB₁. Thus, the apparent species differences previously reported for the pulmonary biotransformation of PGA can result from differences in the perfusion medium used. Our data suggest that both plasma protein binding and a transport system play important roles in determining the selectivity of the uptake of PGs by the lung.     

AB5 toxins: structures and inhibitor design

High-resolution crystal structures of AB₅ toxins in their native form or in complex with a variety of ligands have led to the structure-based design and discovery of inhibitors targeting different areas of the toxins. The most significant progress is the development of highly potent multivalent ligands that block binding of the toxins to their receptors.     

Antiviral Activity of a Small Molecule Deubiquitinase Inhibitor Occurs via Induction of the Unfolded Protein Response

Ubiquitin (Ub) is a vital regulatory component in various cellular processes, including cellular responses to viral infection. As obligate intracellular pathogens, viruses have the capacity to manipulate the ubiquitin (Ub) cycle to their advantage by encoding Ub-modifying proteins including deubiquitinases (DUBs). However, how cellular DUBs modulate specific viral infections, such as norovirus, is poorly understood. To examine the role of DUBs during norovirus infection, we used WP1130, a small molecule inhibitor of a subset of cellular DUBs. Replication of murine norovirus in murine macrophages and the human norovirus Norwalk virus in a replicon system were significantly inhibited by WP1130. Chemical proteomics identified the cellular DUB USP14 as a target of WP1130 in murine macrophages, and pharmacologic inhibition or siRNA-mediated knockdown of USP14 inhibited murine norovirus infection. USP14 is a proteasome-associated DUB that also binds to inositol-requiring enzyme 1 (IRE1), a critical mediator of the unfolded protein response (UPR). WP1130 treatment of murine macrophages did not alter proteasome activity but activated the X-box binding protein-1 (XBP-1) through an IRE1-dependent mechanism. In addition, WP1130 treatment or induction of the UPR also reduced infection of other RNA viruses including encephalomyocarditis virus, Sindbis virus, and La Crosse virus but not vesicular stomatitis virus. Pharmacologic inhibition of the IRE1 endonuclease activity partially rescued the antiviral effect of WP1130. Taken together, our studies support a model whereby induction of the UPR through cellular DUB inhibition blocks specific viral infections, and suggest that cellular DUBs and the UPR represent novel targets for future development of broad spectrum antiviral therapies.     

Geographic Variation of Failure-to-Rescue in Public Acute Hospitals in New South Wales,Australia

Despite the wide acceptance of Failure-to-Rescue (FTR) as a patient safety indicator (defined as the deaths among surgical patients with treatable complications), no study has explored the geographic variation of FTR in a large health jurisdiction. Our study aimed to explore the spatiotemporal variations of FTR rates across New South Wales (NSW), Australia. We conducted a population-based study using all admitted surgical patients in public acute hospitals during 2002–2009 in NSW, Australia. We developed a spatiotemporal Poisson model using Integrated Nested Laplace Approximation (INLA) methods in a Bayesian framework to obtain area-specific adjusted relative risk. Local Government Area (LGA) was chosen as the areal unit. LGA-aggregated covariates included age, gender, socio-economic and remoteness index scores, distance between patient residential postcode and the treating hospital, and a quadratic time trend. We studied 4,285,494 elective surgical admissions in 82 acute public hospitals over eight years in NSW. Around 14% of patients who developed at least one of the six FTR-related complications (58,590) died during hospitalization. Of 153 LGAs, patients who lived in 31 LGAs, accommodating 48% of NSW patients at risk, were exposed to an excessive adjusted FTR risk (10% to 50%) compared to the state-average. They were mostly located in state''s centre and western Sydney. Thirty LGAs with a lower adjusted FTR risk (10% to 30%), accommodating 8% of patients at risk, were mostly found in the southern parts of NSW and Sydney east and south. There were significant spatiotemporal variations of FTR rates across NSW over an eight-year span. Areas identified with significantly high and low FTR risks provide potential opportunities for policy-makers, clinicians and researchers to learn from the success or failure of adopting the best care for surgical patients and build a self-learning organisation and health system.