Porcine rabies in a closed feeder barn

Rabies was diagnosed in a 40 kg pig from a closed feeder barn in which recently unexplained deaths of eight to ten pigs had occurred. A stray cat, probably crawling through a ventilation duct into the barn, was the suspected vector. Over a four and one-quarter year period a disproportionate 53 cases of animal rabies had been diagnosed within a 5 km radius of the farm (13% of the cases in the county in 3% of the county area). Histological lesions, mostly lymphocytic cuffing of blood vessels in the brain with lymphocytic meningitis, patchy to focal gliosis and satellitosis with neuronal necrosis were nonspecific and Negri bodies were rare. Fluorescent antibody technique examination of the brain for rabies virus antigen was positive.     

Mapping Quantitative Field Resistance Against Apple Scab in a 'Fiesta' x 'Discovery' Progeny

ABSTRACT Breeding of resistant apple cultivars (Malus x domestica) as a disease management strategy relies on the knowledge and understanding of the underlying genetics. The availability of molecular markers and genetic linkage maps enables the detection and the analysis of major resistance genes as well as of quantitative trait loci (QTL) contributing to the resistance of a genotype. Such a genetic linkage map was constructed, based on a segregating population of the cross between apple cvs. Fiesta (syn. Red Pippin) and Discovery. The progeny was observed for 3 years at three different sites in Switzerland and field resistance against apple scab (Venturia inaequalis) was assessed. Only a weak correlation was detected between leaf scab and fruit scab. A QTL analysis was performed, based on the genetic linkage map consisting of 804 molecular markers and covering all 17 chromosomes of apple. With the maximum likelihood-based interval mapping method, eight genomic regions were identified, six conferring resistance against leaf scab and two conferring fruit scab resistance. Although cv. Discovery showed a much stronger resistance against scab in the field, most QTL identified were attributed to the more susceptible parent 'Fiesta'. This indicated a high degree of homozygosity at the scab resistance loci in 'Discovery', preventing their detection in the progeny due to the lack of segregation.     

The chemical genomic portrait of yeast: uncovering a phenotype for all genes

Genetics aims to understand the relation between genotype and phenotype. However, because complete deletion of most yeast genes ( approximately 80%) has no obvious phenotypic consequence in rich medium, it is difficult to study their functions. To uncover phenotypes for this nonessential fraction of the genome, we performed 1144 chemical genomic assays on the yeast whole-genome heterozygous and homozygous deletion collections and quantified the growth fitness of each deletion strain in the presence of chemical or environmental stress conditions. We found that 97% of gene deletions exhibited a measurable growth phenotype, suggesting that nearly all genes are essential for optimal growth in at least one condition.     

Thymine dimerization in DNA is an ultrafast photoreaction

Femtosecond time-resolved infrared spectroscopy was used to study the formation of cyclobutane dimers in the all-thymine oligodeoxynucleotide (dT)18 by ultraviolet light at 272 nanometers. The appearance of marker bands in the time-resolved spectra indicates that the dimers are fully formed approximately 1 picosecond after ultraviolet excitation. The ultrafast appearance of this mutagenic photolesion points to an excited-state reaction that is approximately barrierless for bases that are properly oriented at the instant of light absorption. The low quantum yield of this photoreaction is proposed to result from infrequent conformational states in the unexcited polymer, revealing a strong link between conformation before light absorption and photodamage.     

Effect of therapeutic dietary biotin on the healing of uncomplicated sole ulcers in dairy cattle--a double blinded controlled study.

The objective of this study was to investigate the influence of orally administered biotin on the healing of uncomplicated sole ulcers in dairy cattle. In a double-blind controlled study, 24 dairy cows with a mild, uncomplicated sole ulcer on a lateral hind claw were given either 40 mg biotin per day or a placebo feed over a period of 50 days. An orthopaedic shoe was fitted to the medial claw of the affected foot. The healing process was assessed clinically and by histological examination of horn samples. In the biotin-treated animals, the newly formed epidermis covering the sole ulcers was found to be of significantly better histological quality after 50 days than at the start of the study. The significant improvement in histological horn quality found in the biotin-treated animals suggests that biotin exerts a positive influence on the healing of sole ulcers, however the study period of 50 days appears to have been too short to permit macroscopic detection of the improvement in horn quality.     

Evaluation of data from mitogen studies in CBA mice: comparison of counts per minute, stimulation index and relative proliferation index.

Lymphocyte proliferation assays were conducted on splenic lymphocytes collected from CBA mice that had been exposed to lead acetate or cadmium chloride for 10 weeks. The ability of mitogens concanavalin A and lipopolysaccharide, as well as purified protein derivative, to induce proliferation in vitro in the presence or absence of macrophages was assessed. Data were compared by using counts per minute (cpm), stimulation index, and relative proliferative index. Data varied considerably within treatment groups performed on different days, which is a typical characteristic of mitogen proliferation investigations. According to cpm data, only 3 of 21 treatments were significantly (P less than 0.05) altered when compared with controls. The stimulation indices were highly influenced by background counts and frequently did not correlate with cpm. The relative proliferative index, on the other hand, calculates net cpm, closely corresponds to cpm, compensates for background counts and is affected less by variation than is the stimulation index, and selected cutoff values give a more sensitive measure for determination of altered proliferative responses when statistical procedures are not applicable. Effects of macrophages, carbon dioxide, and bovine fetal serum on lymphocyte transformation are discussed.     

Strangulation of the duodenum by the uterus during late pregnancy in two cows.

Two Swiss Braunvieh cows in late pregnancy underwent surgery because of a rare form of ileus due to strangulation of the duodenum at its caudal flexure by the gravid uterus. The whole uterus had passed through a gap between the mesoduodenum and duodenum and with increasing weight had led to strangulation of the duodenum. This was possible since the mesoduodenum and both walls of the greater omentum adjacent to its caudal edge were not connected with the duodenum, probably due to a congenital inhibitory malformation. A transsection and an end-to-end anastomosis of the duodenum were necessary in both cases since it was impossible to retract the gravid uterus through the defect. Postoperative recovering was uneventful in both cows, which were discharged after seven and five days respectively and calved normally about two months later. Copyright Harcourt Publishers Ltd.