Synthesis of Protocatechuate Oxygenase by Pseudomonas fluorescens in the Presence of Exogenous Carbon Sources.

Kirkland, Jerry J. (Oklahoma State University, Stillwater), and Norman N. Durham. Synthesis of protocatechuate oxygenase by Pseudomonas fluorescens in the presence of exogenous carbon sources. J. Bacteriol. 90:15-22. 1965.-The addition of glucose, ribose, or fructose (0.45 or 45.0 mumoles/ml) simultaneously with protocatechuic acid shortens the lag period required for synthesis of protocatechuate oxygenase by a washed-cell suspension of Pseudomonas fluorescens. Glucose is readily oxidized and supports growth of P. fluorescens, whereas neither ribose nor fructose readily supports growth. High glucose concentrations (45.0 mumoles/ml) shorten the lag period but lower the total enzyme synthesis. The pH drops during glucose oxidation, and this is accompanied by a decrease in the rate of enzyme synthesis. High glucose concentrations, with adequate buffering, permitted "normal" enzyme synthesis. A decrease in the total enzyme synthesis was not observed in the presence of high concentrations of ribose or fructose. Succinate, pyruvate, acetate, or formate (0.45 mumole/ml) were readily oxidized, but did not shorten the lag period required for synthesis of the enzyme. The data suggest that glucose, ribose, or fructose may serve as a "specific" carbon source (such as ribose-5-phosphate or a similar precursor important in ribonucleic acid synthesis) functional in the synthesis of protocatechuate oxygenase.     

Epidemiology of bovine ephemeral fever in Australia 1981-1985

Bovine ephemeral fever is an important viral disease of cattle in Australia. The disease occurred each year, principally in summer and autumn, between 1981 and 1985. Queensland and the northern half of New South Wales were areas of greatest activity with only sporadic cases being reported from the Northern Territory and the northern third of Western Australia. Since 1981, the disease has been endemic in an extensive area of eastern Australia and has tended to occur in widely scattered outbreaks rather than the north-south advancing wave form of the epidemics of 1936-37, 1967-68, 1970-71 and 1972-74. The southernmost outbreaks between 1981 and 1985 were well within the limits of these earlier epidemics. The pattern of disease appears to have become seasonally endemic rather than periodically endemic in the northern two-thirds of eastern Australia. Ephemeral fever was not recorded in Victoria, Tasmania, South Australia or the southern part of Western Australia between 1981 and 1985. The disease was most frequently reported in cattle under 3 years of age, but also occurred in older cattle.     

Routes of Hendra Virus Excretion in Naturally-Infected Flying-Foxes: Implications for Viral Transmission and Spillover Risk

Pteropid bats or flying-foxes (Chiroptera: Pteropodidae) are the natural host of Hendra virus (HeV) which sporadically causes fatal disease in horses and humans in eastern Australia. While there is strong evidence that urine is an important infectious medium that likely drives bat to bat transmission and bat to horse transmission, there is uncertainty about the relative importance of alternative routes of excretion such as nasal and oral secretions, and faeces. Identifying the potential routes of HeV excretion in flying-foxes is important to effectively mitigate equine exposure risk at the bat-horse interface, and in determining transmission rates in host-pathogen models. The aim of this study was to identify the major routes of HeV excretion in naturally infected flying-foxes, and secondarily, to identify between-species variation in excretion prevalence. A total of 2840 flying-foxes from three of the four Australian mainland species (Pteropus alecto, P. poliocephalus and P. scapulatus) were captured and sampled at multiple roost locations in the eastern states of Queensland and New South Wales between 2012 and 2014. A range of biological samples (urine and serum, and urogenital, nasal, oral and rectal swabs) were collected from anaesthetized bats, and tested for HeV RNA using a qRT-PCR assay targeting the M gene. Forty-two P. alecto (n = 1410) had HeV RNA detected in at least one sample, and yielded a total of 78 positive samples, at an overall detection rate of 1.76% across all samples tested in this species (78/4436). The rate of detection, and the amount of viral RNA, was highest in urine samples (>serum, packed haemocytes >faecal >nasal >oral), identifying urine as the most plausible source of infection for flying-foxes and for horses. Detection in a urine sample was more efficient than detection in urogenital swabs, identifying the former as the preferred diagnostic sample. The detection of HeV RNA in serum is consistent with haematogenous spread, and with hypothesised latency and recrudesence in flying-foxes. There were no detections in P. poliocephalus (n = 1168 animals; n = 2958 samples) or P. scapulatus (n = 262 animals; n = 985 samples), suggesting (consistent with other recent studies) that these species are epidemiologically less important than P. alecto in HeV infection dynamics. The study is unprecedented in terms of the individual animal approach, the large sample size, and the use of a molecular assay to directly determine infection status. These features provide a high level of confidence in the veracity of our findings, and a sound basis from which to more precisely target equine risk mitigation strategies.     

Multifactorial approach and superior treatment efficacy in renal patients with the aid of nurse practitioners. Design of The MASTERPLAN Study [ISRCTN73187232]

Background

Patients with chronic kidney disease (CKD) are at a greatly increased risk of developing cardiovascular disease. Recently developed guidelines address multiple risk factors and life-style interventions. However, in current practice few patients reach their targets. A multifactorial approach with the aid of nurse practitioners was effective in achieving treatment goals and reducing vascular events in patients with diabetes mellitus and in patients with heart failure. We propose that this also holds for the CKD population.

Design

MASTERPLAN is a multicenter randomized controlled clinical trial designed to evaluate whether a multifactorial approach with the aid of nurse-practicioners reduces cardiovascular risk in patients with CKD. Approximately 800 patients with a creatinine clearance (estimated by Cockcroft-Gault) between 20 to 70 ml/min, will be included. To all patients the same set of guidelines will be applied and specific cardioprotective medication will be prescribed. In the intervention group the nurse practitioner will provide lifestyle advice and actively address treatment goals. Follow-up will be five years. Primary endpoint is the composite of myocardial infarction, stroke and cardiovascular mortality. Secondary endpoints are cardiovascular morbidity, overall mortality, decline of renal function, change in markers of vascular damage and change in quality of life. Enrollment has started in April 2004 and the study is on track with 700 patients included on October 15th, 2005. This article describes the design of the MASTERPLAN study.     

Identification of lipopolysaccharide-binding proteins in 70Z/3 cells by photoaffinity cross-linking

A radioiodinated, photoactivatable derivative of Salmonella minnesota Re595 lipopolysaccharide (LPS) was used to label LPS-binding proteins in 70Z/3 cells. The labeled proteins were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and visualized by autoradiography. 125I-Labeled-2-(p-azidosalycylamido)1,3'-dithiopropionamide S. minnesota Re595 LPS (125I-ASD-Re595) labeled a limited number of proteins. The most prominent of these had a apparent molecular mass of 18 kDa. Less prominent labeling of 25- and 28-kDa proteins was also seen. Labeling was saturated by 5 micrograms/ml 125I-ASD-Re595 and was inhibited by a 10-100-fold excess of unlabeled LPS or lipid A. Labeling was maximal within 30 min at 37 degrees C; much less labeling occurred at lower temperatures. The proteins labeled with 125I-ASD-Re595 appear to be on the surface of the cell, since they can be digested by trypsin and were found in the membrane fraction of the cell but not in the cytosol. Studies with competitive inhibitors suggested that the proteins bind to the lipid A region of the LPS molecule. Biologically inactive lipid A analogs were poor inhibitors of labeling, suggesting that the LPS-binding proteins could discriminate between active lipid A and inactive analogs. These studies suggest that the 18- and 25-kDa proteins bind specifically to the lipid A region of the LPS molecule and should be considered as candidates for a functional LPS receptor.     

Changes measured in arterial blood following a single breath of cigarette smoke in rabbits.

This paper describes a method for monitoring short term changes in arterial blood in rabbits in response to a single breath of cigarette smoke. The method was developed to investigate the observation that neutrophil transit times through the lung are extended during acute exposures to cigarette smoke (1). In this model, we sought to monitor the time course of appearance of diffusible gas from smoke to the blood stream, the appearance of lipid peroxidation products and the activation of neutrophils. New Zealand white rabbits were anesthetized and fitted with a tracheostomy tube and an aortic catheter. Smoke was collected in a syringe from a non-filtered cigarette and injected immediately via the tracheostomy tube. Blood samples were collected at 1 second intervals. Carboxyhemoglobin levels increased 108% over pre-smoke levels, peaking at 5-7 seconds after the start of smoke exposure. Serum conjugated dienes, as measured by change in absorbance of lipid extracts at 234 nm, increased 40%, peaking at 10-11 seconds. Thiobarbituric acid (TBA) reactive material exhibited a variable response, with a statistically insignificant maximum at 12 seconds. Serum myeloperoxidase activity was not affected by smoke inhalation. This method provides a model for studying the acute effects of smoke inhalation and provides some evidence for oxidant stress following a single breath of cigarette smoke.     

An investigation of the photo-clastogenic potential of ultrafine titanium dioxide particles

Ultrafine titanium dioxide is widely used in a number of commercial products including sunscreens and cosmetics. There is extensive evidence on the safety of ultrafine titanium dioxide. However, there are some published studies indicating that some forms at least may be photogenotoxic, photocatalytic and/or carcinogenic. In order to clarify the conflicting opinions on the safety of ultrafine titanium dioxide particles, the current studies were performed to investigate the photo-clastogenic potential of eight different classes of ultrafine titanium dioxide particles. The photo-clastogenicity of titanium dioxide was measured in Chinese hamster ovary (CHO) cells in the absence and presence of UV light at a dose of 750 mJ/cm². The treatments were short (3 h) followed by a 17-h recovery and achieved concentrations that either induced approximately 50% cytotoxicity or reached 5000 μg/ml if non-cytotoxic. None of the titanium dioxide particles tested induced any increase in chromosomal aberration frequencies either in the absence or presence of UV. These studies show that ultrafine titanium dioxide particles do not exhibit photochemical genotoxicity in the model system used.