Inhibition of Saprolegnia pathogenic for fish by Pseudomonas fluorescens

Bacteria capable of inhibiting the growth of Saprolegnia were isolated from commercial channel catfish pond water during January and November 1991. The isolates were typed as Pseudomonas fluorescens with 96% confidence and fluoresced under ultraviolet light. Only three out of the seven otherwise identical subcultures have retained the ability to inhibit Saprolegnia hyphal growth and were positive in gelatin liquefaction assays. Saprolegnia cyst germination inhibition assays indicated that each of the P. fluorescens subcultures inhibited cyst germination at ratios as low as 0.5:1 to 10:1, while Escherichia coli (used as a control) was only inhibitory at a ratio of 500:1. The inhibitory activity against Saprolegnia did not appear to reside in bacterial culture supernatants.     

Atmospheric sulfur aerosol concentrations and characteristics from the South american continent

Aerosol samples collected from eight geographically distinct locations in South America during the austral winter of 1976 and summer of 1977 with six-stage cascade impactors show a tropospheric sulfur background concentration of about 50 nanograms per cubic meter of air in the fine-particle mode (1 micrometer in aerodynamic diameter). Time-sequence filter samples, taken concurrently at most locations, show an average non-sea spray related sulfur concentration of about 85 nanograms per cubic meter. These concentrations are substantially lower than most published nonurban values for the Northern Hemisphere obtained by similar sampling and analysis techniques and may represent a natural tropospheric background level of aerosol sulfur.     

Dynamics of the free-living stages of sheep intestinal parasites on pasture in the North Island of New Zealand. 2. Weather variables associated with development

Abstract

AIM: To identify weather variables associated with the development of eggs of Teladorsagia (=Ostertagia) circumcincta, Trichostrongylus colubriformis and Haemonchus contortus to third-stage infective larvae (L3) under a range of climatic conditions on pasture in the North Island of New Zealand.

METHODS: Sheep faeces containing known numbers of eggs of all three nematode species were deposited on, or buried in, pasture plots at three sites, viz coastal Manawatu, Upper Hutt Valley, and East Cape hill country. Development was measured by recovering L3 from faeces, herbage and soil 28–31 days after deposition, on 13–18 occasions between January 2005 until July 2006. Weather data were recorded at each site, and the association between weather variables and number of L3 recovered was analysed using subsets regression to select best-fitting models from several candidate variables, after adjustment for efficiency of recovery of L3. A multiple linear regression model was then developed for each species, to select weather variables that had both significant and substantive effects on the number of L3 recovered.

RESULTS: For all species, mean daily temperature was the bestpredictor of the number of L3 recovered (p=0.001). For T.circumcincta the final model included mean daily temperature and soil temperature (R²=51%), and for T. colubriformis the model only included mean daily temperature (R²=55%). For development of H. contortus, mean daily temperature was the most significant variable, but moisture in the form of rainfall entropy, i.e. the temporal distribution of rainfall, overthe first 14 days was also significant in the final model (R²=34%).

CONCLUSIONS: Temperature was the most important determinant of developmental success of free-living nematodes on pasture at the study sites, and probably also for other parts ofNew Zealand with similar climates. Moisture was not significant in the development of T. circumcincta or T.colubriformis, implying that under the generally moist temperate climate in New Zealand, moisture is seldom limiting for development of these species. Haemonchus contortusappeared to be sensitive to moisture availability and precipitation in the first 14 days after deposition of faeces. The results of this study will be further developed as part of species-specific climate-driven models of parasite development in New Zealand.     

The potential for monitoring and control of insect pests in Southern Hemisphere forestry plantations using semiochemicals

Context

Southern Hemisphere plantation forestry has grown substantially over the past few decades and will play an increasing role in fibre production and carbon sequestration in future. The sustainability of these plantations is, however, increasingly under pressure from introduced pests. This pressure requires an urgent and matching increase in the speed and efficiency at which tools are developed to monitor and control these pests.

Aim

To consider the potential role of semiochemicals to address the need for more efficient pest control in Southern Hemisphere plantations, particularly by drawing from research in other parts of the world.

Results

Semiochemical research in forestry has grown exponentially over the last 40?years but has been almost exclusively focussed on Northern Hemisphere forests. In these forests, semiochemicals have played an important role to enhance the efficiency of integrated pest management programmes. An analysis of semiochemical research from 1970 to 2010 showed a rapid increase over time. It also indicated that pheromones have been the most extensively studied type of semiochemical in forestry, contributing to 92% of the semiochemical literature over this period, compared with research on plant kairomones. This research has led to numerous applications in detection of new invasions, monitoring population levels and spread, in addition to controlling pests by mass trapping or disrupting of aggregation and mating signals.

Conclusion

The value of semiochemicals as an environmentally benign and efficient approach to managing forest plantation pests in the Southern Hemisphere seems obvious. There is, however, a lack of research capacity and focus to optimally capture this opportunity. Given the pressure from increasing numbers of pests and reduced opportunities to use pesticides, there is some urgency to develop semiochemical research capacity.     

Safety and immunogenicity of ERA strain of rabies virus propagated in a BHK-21 cell line.

The ERA strain of rabies virus was propagated in a baby hamster kidney cell line (BHK-21/C13). The viral titer was 10(1.8) tissue culture infective doses (TCID) higher than that of commercial ERA vaccine. The ERA/BHK-21 vaccine in baits retained titers of 10(6.3) to 10(6.4), TCID when subjected to daily temperature fluctuations from 9 degrees C to 24 degrees C for 21 days. This titer, according to a dose response in laboratory foxes, was still capable of immunizing up to 100% of foxes consuming a bait. The ERA/BHK-21 vaccine, when presented in baits, produced antibodies in 80 to 100% of dogs consuming more than one bait. Duration of immunity in foxes, from feeding the ERA strain rabies virus in baits, as determined by resistance to challenge with virulent virus, was at least 48 months. The vaccine strain retained some pathogenicity for nontarget species. In tests carried out on foxes, raccoons, dogs, cats and cattle, the vaccine did not cause vaccine-induced rabies. One of 14 skunks which consumed four baits developed vaccine-induced rabies, but virus could not be isolated from the salivary glands of this animal. The vaccine, when presented in baits, caused vaccine-induced rabies in 37% of laboratory mice, 3.4% of Microtus and 2.6% of Peromyscus species. Rabies virus could not be isolated from the salivary glands of rodents with vaccine-induced rabies. It was concluded that ERA virus propagated in BHK-21/C13 cells and incorporated in an acceptable bait produced a high titer, stable, immunogenic and safe vaccine for foxes.     

Prevalence of udder bacteria in milk samples from four dairy goat herds

The prevalence of udder bacterial infections in 4 commercial goat herds in New South Wales was examined. Coagulase negative staphylococci were the predominant bacteria isolated being cultured from 13.3% of the 896 halves tested. Other bacteria isolated were Staphylococcus aureus (less than 1% of halves), streptococci (0.6%) and coliforms (2.0%). The low prevalence of udder bacteria contributing to the contamination of the milk was attributed to the milking management practices carried out in these herds, in particular pre-milking and post-milking antisepsis.     

A study on the possible role of chymotrypsin in the aetiology of equine chronic obstructive pulmonary disease (COPD)

The chymotrypsin activity of seven batches of Micropolyspora faeni and of five batches of Aspergillus fumigatus culture extracts, prepared for inhalation challenge in horses, was assayed and was found to range between 0.29 and 1.45 units/mg protein and 0.02 and 0.20 units/mg protein respectively. Horses affected with chronic obstructive pulmonary disease (COPD) were challenged with two batches of each antigen which had different chymotrypsin activities and no significant correlations were found between the degree of response to challenge and the chymotrypsin activity of the antigens. Inhalation of two doses of nebulised, purified chymotrypsin over 4 days did not induce signs of respiratory disease in COPD-affected horses. However, repeated chymotrypsin inhalations after an interval of 3 weeks caused an exacerbation of signs of COPD in one horse. These studies suggest that, although repeated inhalation of purified chymotrypsin may induce respiratory hypersensitivity in horses, the chymotrypsin-like enzymes of M. faeni and A. fumigatus do not play a major role in the precipitation of clinical signs of equine COPD.     

Simple radiography as an aid to the diagnosis of heart disease in the dog

Abstract— —The intention of this paper is to show how simple, plain radiography of the thorax can be a useful aid to the diagnosis of heart disease in the dog. The only radiographic changes that will be discussed are those that can be demonstrated on lateral and dorso-ventral radiographs of the thorax which are easily obtainable by any veterinary surgeon with a reasonable X-ray machine. The use of intravascular and intracardiac contrast media and other of the more complex techniques which have been evolved to demonstrate cardiac structure and function in detail will not be discussed. Résumé— —Le but de ce compte-rendu est de démontrer que la simple radiographie du thorax peut être une aide utile à la diagnose de maladie de coeur chez le chien. Les seuls changements radio-graphiques qui seront discutés sont ceux qui peuvent être démontrés sur des radiographies latérales et dorso ventrales du thorax qui sont facilement obtenables par un chirurgien vétérinaire avec une machine moyenne de Rayons-X. L'emploi du moyenne de contraste intavasculaire et intracardiaque et d'autres techniques plus complexes qui sont issues pour démontrer la structure et la fonction cardiaque en détails ne sera pas discuté. Zusammenfassung— —Der Zweck dieser Abhandlung ist vorzuführen, wie einfache, unkomplizierte Röntgenphotographie des Brustkorbes einen nützlichen Beitrag zue Diagnose von Herzfehlern bei Hunden leisten kann. Es werden nur solche röntgenologischen Veränderungen besprochen, die auf seitlichen und dorsoventralen Röntgenbildern des Brustkorbes nachgewiesen werden können und deren Aufnahme ganz leicht von jedem tierärztlichen Chirurgen mit einem passablen Röntgen-apparat gemacht werden können. Die Verwendung von intravaskulären und intrakardiologischen Kontrastmitteln und anderen komplizierteren Methoden, die für eine ausführliche Demonstration der Herzstruktur und Funktion entwickelt wurden, wird nicht besprochen.