Rotavirus replication in colostrum-fed and colostrum-deprived pigs

A porcine rotavirus isolate was titrated in neonatal colostrum-fed and colostrum-deprived pigs. The stock rotavirus suspension had a titer of 10(-6.5)/ml and was in its fifteenth cell culture passage in MA-104 cells. Fourteen colostrum-fed pigs were orally inoculated with dilutions of the stock virus suspension ranging from undiluted to 10(-5). These pigs did not develop notable clinical signs during the 7-day experimental trial and no pathologic changes were found in intestine, liver, lung, kidney, spleen, or brain. However, rotavirus was detected in feces of the colostrum-fed pigs, using virus isolation and electron microscopic techniques. Rotavirus was also isolated from lung, brain, or spleen of 4 of 12 of these pigs. Sixteen colostrum-deprived pigs were orally inoculated with dilutions of the stock virus suspension ranging from 10(-1) to 10(-8). Diarrhea developed in 10 of 12 pigs that were given up to the 10(-6) dilution. Seven of these 12 pigs died because of the severity of diarrhea. Pigs that died of rotavirus-induced diarrhea had severe villus loss in the jejunum and ileum. Villi of the small intestine of colostrum-deprived pigs that survived the severe diarrhea were within normal limits at the end of the 7-day trial. The colostrum-deprived pigs that were inoculated with a dilution less than 10(-6) and survived past 96 hours underwent seroconversion. Rotavirus was detected by virus isolation and electron microscopy in the feces of all colostrum-deprived pigs that survived beyond 18.5 hours after inoculation. Virus was isolated from lungs, brain, or spleen of 12 of 16 colostrum-deprived pigs.     

The role of seeds and airborne inoculum in the initiation of leaf blotch (Rhynchosporium secalis) epidemics in winter barley

Both airborne spores of Rhynchosporium secalis and seed infection have been implied as major sources of primary inoculum for barley leaf blotch (scald) epidemics in fields without previous history of barley cropping. However, little is known about their relative importance in the onset of disease. Results from both quantitative real‐time PCR and visual assessments indicated that seed infection was the main source of inoculum in the field trial conducted in this study. Glasshouse studies established that the pathogen can be transmitted from infected seeds into roots, shoots and leaves without causing symptoms. Plants in the field trial remained symptomless for approximately four months before symptoms were observed in the crop. Covering the crop during part of the growing season was shown to prevent pathogen growth, despite the use of infected seed, indicating that changes in the physiological condition of the plant and/or environmental conditions may trigger disease development. However, once the disease appeared in the field it quickly became uniform throughout the cropping area. Only small amounts of R. secalis DNA were measured in 24 h spore‐trap tape samples using PCR. Inoculum levels equivalent to spore concentrations between 30 and 60 spores per m³ of air were only detected on three occasions during the growing season. The temporal pattern and level of detection of R. secalis DNA in spore tape samples indicated that airborne inoculum was limited and most likely represented rain‐splashed conidia rather than putative ascospores.     

Edge effects and arboreal Collembola in coniferous plantations

We report on the distribution of arboreal Collembola in relation to canopy microclimatic conditions and distance from a forest edge. Collembola were collected by pyrethrum misting from the canopy of 12 m commercial plantations of Pinus sylvestris and Picea sitchensis at two sites in northern England, using transects running perpendicularly from a sharp edge (against open moorland). Temperature and humidity were co-recorded at 1.5 m elevation. Eleven species of Collembola were recorded, dominated by four known to be arboreal (Entomobrya nivalis, Lepidocyrtus lanuginosus, Vertagopus arboreus and Anurophorus laricis) but also including small numbers of supposedly edaphic forms, notably Protaphorura armata. All species were at higher density in the P. sitchensis plantations, but otherwise displayed no consistent community structure. Only four significant edge effects were detected in the Collembola data (out of 60 tests), none of which fitted an exponential model. By contrast the majority of the micro-meteorological data showed significant edge effects which were well modelled by an exponential function. It is concluded that the distribution of arboreal Collembola showed no edge effects, despite the latter being detectable in their meteorological environment.     

Candida rugosa lipase LIP1-catalyzed transesterification to produce human milk fat substitute

Structured lipids (SLs) containing palmitic and oleic acids were synthesized by transesterification of tripalmitin with either oleic acid or methyl oleate as acyl donor. This SL with palmitic acid at the sn-2 position and oleic acid at sn-1,3 positions is similar in structure to human milk fat triacylglycerol. LIP1, an isoform of Candida rugosa lipase (CRL), was used as biocatalyst. The effects of reaction temperature, substrate molar ratio, and time on incorporation of oleic acid were investigated. Reaction time and temperature were set at 6, 12, and 24 h, and 35, 45, and 55 degrees C, respectively. Substrate molar ratio was varied from 1:1 to 1:4. The highest incorporation of oleic acid (37.7%) was at 45 degrees C with methyl oleate as acyl donor. Oleic acid resulted in slightly lesser (26.3%) incorporation. Generally, higher percentage incorporation of oleic acid was observed with methyl oleate (transesterification) than with oleic acid (acidolysis). In both cases percentage incorporation increased with reaction time. Incorporation decreased with increase in temperature above 45 degrees C. Initially, oleic acid incorporation increased with increase in substrate molar ratio up to 1:3. LIP1 was also compared with Lipozyme RM IM as biocatalysts. The tested reaction parameters were selected on the basis of maximum incorporation of C18:1 obtained during optimization of LIP1 reaction conditions. Reaction temperature was maintained at 45, 55, and 65 degrees C. Lipozyme RM IM gave highest oleic acid incorporation (49.4%) at 65 degrees C with methyl oleate as acyl donor. Statistically significant (P < 0.05) differences were observed for both enzymes. SL prepared using Lipozyme RM IM may be more suitable for possible use in human milk fat substitutes.     

Bluetongue and epizootic hemorrhagic disease in white-tailed deer from Oklahoma: serologic evaluation and virus isolation

Blood samples were collected from 194 white-tailed deer from 27 locations in Oklahoma from 1977 through 1984. Sixty-eight (35%) of the deer had antibody against bluetongue virus (BTV) and 78 (40%) had antibody against epizootic hemorrhagic disease virus. Seropositive deer were detected in each of the 4 geographic quadrants of the state. Virus isolation was attempted in 40 deer from the northeast quadrant of Oklahoma (1983 through 1984); BTV was isolated from 11 deer, but epizootic hemorrhagic disease virus was not isolated. The isolation of BTV serotype 11 from these deer from 1983 through 1984 coincided with reported isolations of this serotype in other ruminants in Oklahoma during this time.     

Structure of human urokinase plasminogen activator in complex with its receptor

The urokinase plasminogen activator binds to its cellular receptor with high affinity and initiates signaling cascades that are implicated in pathological processes including tumor growth, metastasis, and inflammation. We report the crystal structure at 1.9 angstroms of the urokinase receptor complexed with the urokinase amino-terminal fragment and an antibody against the receptor. The three domains of urokinase receptor form a concave shape with a central cone-shaped cavity where the urokinase fragment inserts. The structure provides insight into the flexibility of the urokinase receptor that enables its interaction with a wide variety of ligands and a basis for the design of urokinase-urokinase receptor antagonists.     

Imported disease of dogs and cats exotic to Ireland: Echinococcus multilocularis

Changes in legislation that facilitate the movement of animals within the European Union may increase the risk that some microbial and parasitic organisms, currently exotic to Ireland, will be introduced by travelled pet animals. It is possible that the fox tapeworm, Echinococcus multilocularis, might be introduced in that manner from any of the several member states in which it is endemic. Red foxes are the principal definitive hosts of E. multilocularis but dogs and cats can also be infected. Infection in the definitive host is of little clinical significance, but aberrant infection of humans results in alveolar echinococcosis, a debilitating disease that has a high mortality rate. Humans acquire the organism by ingestion of Echinococcus multilocularis eggs excreted by definitive hosts; the larval metacestodes develop primarily in the liver, in the initial asymptomatic phase as small, well-encapsulated cysts. Over time, perhaps five to 15 years, progressive local infiltration and secondary cyst development at distant sites occur with resultant clinical signs. Patients with infiltrative liver disease present with cholestatic jaundice, epigastric pain, fatigue, weight loss and hepatomegaly. If left untreated, the disease can be fatal.This paper recounts the life cycle of the parasite, and discusses the control measures on which its exclusion from Ireland depend. Strict adherence to the routine worming of travelled dogs with praziquantel, at appropriate doses, 24 to 48 hours prior to entry into the country will minimise the likelihood of introduction of this zoonosis.