PCR cloning, DNA sequencing and phylogenetic analysis of a xylanase gene from the phytopathogenic fungusAscochyta pisiLib.

A gene encoding a xylanase,xyl1, was isolated from the phytopathogenic fungusAscochyta pisiLib. by PCR cloning using degenerate primers. DNA sequence analysis revealed an open reading frame of 736 bp interrupted by an intron of 55 bp. The ORF encodes a predicted protein of 227 amino acids. The precise splicing site of the intron was identified from the sequence of a PCR product obtained using the same degenerated primers on a cDNA template. The cDNA product and a northern blot demonstrated that the gene is transcribed into mRNA when the fungus is cultured in media containing xylan as sole carbon source. The Neighbour-Joining method using the Clustal W(1.5) program demonstrated that theA. pisixylanase is a member of the family 11 glycosyl hydrolases, and that this family represents at least five phylogenetically consistent groups. The family 11 glycosyl hydrolases can be linked with family 10 glycosyl hydrolyses through bifunctional enzymes fromRuminococcus flavefaciensand, to a lesser extentNeocallimastix patriciarum.     

What are the prospects for genetically engineered,disease resistant plants?

Insect and herbicide-resistant plants are the most widely grown transgenics in agricultural production. No strategy using genetically engineered plants for disease resistance has had a comparable impact. Why is this? What are the prospects for introducing transgenic disease resistant plants to agriculture? We review the biological background for strategies used to make disease resistant GM crops, illustrate examples of these different strategies and discuss future prospects.     

Benign masses in the pericardium of two dogs

Two miniature Schnauzer dogs were treated for pericardial masses. In one dog the mass consisted of necrotic fat that was attached to the apex of the pericardium by a pedicle. No obvious communication with the abdomen was present. The second dog had a peritoneopericardial hernia associated with a chronic cystic haematoma. In each case the mass was presumed to have arisen following congenital displacement of the omentum into the pericardium. The pericardial mass was removed and subtotal pericardectomy performed in both dogs. Recovery was complete in each case.     

Evaluation of d,l-ethionine as a mechanism for pancreatic islet regeneration in dogs

Objective To determine whether induction of pancreatic necrosis and islet proliferation by d,l‐ethionine has potential for treating dogs with b ‐cell insufficiency. Design Eighteen mixed breed dogs of both sexes were given d,l‐ethionine at 100 mg/kg three times weekly for 2 weeks; 6 dogs were euthanased at 2, 14 and 28 d after the last dose. Methods Clinical signs during administration and recovery were assessed. Routine biochemical analyses were performed before each ethionine dose and then once weekly. Faecal samples were examined weekly for malassimilated nutrients and blood. Blood coagulation screening tests (OSPT and APTT) were determined on four dogs after ethionine administration. Intravenous glucose tolerance tests were conducted before the first and after the last ethionine dose and then fortnightly. All dogs were necropsied and pancreas, liver, kidney and jejunum were examined microscopically. Results During ethionine administration all animals displayed vomiting, inappetence, diarrhoea (often with blood), weight loss and depression. Three dogs were euthanased prematurely due to severe illness, but those allowed to recover were eating and brighter 7 d after cessation of ethio‐nine administration. Serum concentrations of TLI, amylase and lipase increased initially, then decreased, during administration but returned to normal during recovery. Concentrations of ALT, ALP, unconjugated and conjugated bilirubin increased during administration then decreased slowly. Histological examination revealed hepatic lipidosis and necrosis, but no renal or jejunal lesions. In most dogs, faecal examination demonstrated increased undigested starch and muscle, as well as increased digested and undigested fat, during ethio‐nine administration or early during the recovery period, suggesting transient malassimilation. APTT was unchanged but OSPT was prolonged in all dogs. There was no impairment of insulin secretion or glucose intolerance and C‐peptide concentrations were unaffected. Immediately after ethionine administration there was delayed insulin degradation and by day 43 there was evidence of increased insulin sensitivity. Conclusion d,l‐ethionine administration in dogs appeared not to interfere with insulin secretion, but caused clinical signs and laboratory changes indicative of pancreatic exocrine necrosis, severe hepatobiliary disease and transient malas‐similation. Pancreatic and hepatic dysfunction was severe but clinical recovery occurred after ethionine administration ceased. The severe side‐effects observed with d,l‐ethionine should preclude its potential use for treating diabetes mellitus in dogs.     

The use of tiletamine hydrochloride and zolazepam hydrochloride for sedation of the mountain brushtail possun Trichosurus caninus Ogilby (Phalangeridae: Marsupialia)

SUMMARY A combination of tiletamine hydrochloride and zolazepam hydrochloride in a 1:1 ratio by weight was used successfully to sedate mountain brushtail possums, Trichosurus caninus, in the field. A standard total dose of 50 to 60 mg provided adequate sedation for the completion of a range of handling procedures. We describe the induction time, dose rate and side-effects associated with the use of tiletamine and zolazepam in T caninus.     

Preferences of veterinarians for drugs to treat heart disease in dogs and cats

SUMMARY Responses (473) were collated from a questionnaire sent to 5054 veterinarians in Australia enquiring about drug preferences for treating cardiac disease in dogs and cats. When treating a small breed dog with endocardiosis and mild left congestive heart failure, 74% of 472 respondents used a diuretic, 67% a theophylline derivative, 27% a vasodilator and 20% a positive inotrope. Frusemide was the preferred diuretic and digoxin the preferred inotrope, but vasodilator use varied. Low sodium diets were “often recommended” by 71% of respondents. Propranolol was preferred to diltiazem for treating feline hypertrophic cardiomyopathy. Digoxin was clearly preferred for treating supraventricular dysrhythmias, while lignocaine and digoxin were preferred equally for ventricular dysrhythmias. Respondents appeared more willing than US veterinarians to use theophylline derivatives and prasozin, and less inclined to employ nitrates, hydralazine, inotropes other than digoxin, and low sodium diets.     

Dynamics of Oxidation of a Fe2+-Bearing Aluminosilicate (Basaltic) Melt

Rutherford backscattering spectroscopy (RBS) and microscopy demonstrate that the approximately 1400°C oxidation of levitated droplets of a natural Fe2+-bearing aluminosilicate (basalt) melt occurs by chemical diffusion of Fe2+ and Ca2+ to the free surface of the droplet; internal oxidation of the melt results from the required counterflux of electron holes. Diffusion of an oxygen species is not required. Oxidation causes the droplets to go subsolidus; magnetite (Fe3O4) forms at the oxidation-solidification front with a morphology suggestive of a Liesegang-band nucleation process.     

Biological control of plant diseases – What has been achieved and what is the direction?

The global sustainability agenda is increasing the demand for reduction in inputs into agricultural production while maintaining profitable yield of quality products. Plant diseases are a major constraint for both yield and product quality, but often tools for their control are ineffective or lacking. Biological control using antagonistic microorganisms has long been a subject of research resulting in a wide range of products that are now available and marketed in specific territories around the world. These preparations are often niche products with narrow uses. The research effort is intense both to develop new biological control agents (BCAs) and to obtain knowledge of the mechanisms underlying biological disease control. The prospects for biological control are promising. As a minimum, BCAs supplement other sustainable disease management practices such as disease resistance, and present opportunities for controlling diseases for which other approaches are ineffective or unavailable. We can realistically expect increasing use of BCAs to control crop diseases in ways that will benefit the environment. This review paper arose from a webinar held by the British Society for Plant Pathology as part of the International Year of Plant Heath (IYPH2020), at which many of the 300 participants posed or discussed interesting questions. This review is based on that input and the panel members at the webinar are all included as co-authors in this review.