Operant supplementary heating in groups of growing pigs in relation to air velocity

The aim of the experiments was to investigate the effect of air velocity on the temperature preferred by growing pigs 12–14 weeks old. Pigs displayed a temperature preference by means of operant supplemental heating. They pushed a button connected to heating lamps. Six experiments of three weeks each and with two treatments with a group of 8 pigs each were made. Animals were housed in groups and weighed 14–20 kg at the start of the experiments. Air velocity was 0.08, 0.25 and 0.40 m/s. At each air velocity four replicates were made. Mean temperatures preferred were 17.9°C at 0.08 m/s, 20.5°C at 0.25 m/s and 21.7°C at 0.40 m/s. Within a day temperature preference fluctuated with 5.7 K at 0.08 m/s, 4.3 K at 0.25 m/s and 4.2 K at 0.4 m/s. Temperatures preferred were highest during day time.     

Tissue site-specific enhancer function of the upstream regulatory region of human papillomavirus type 11 in cultured keratinocytes.

The human papillomavirus type 11 regulatory region was cloned upstream of a reporter complex and microinjected into nuclei of individual primary human keratinocytes. Genital and laryngeal keratinocytes, normal host cells for this virus, exhibited higher levels of expression than cutaneous keratinocytes. We conclude that a papillomavirus enhancer(s) shows preferences among epithelial cells from different tissue sites.     

High efficiency, long-term clinical expression of cottontail rabbit papillomavirus (CRPV) DNA in rabbit skin following particle-mediated DNA transfer.

The ability of skin to support long lasting expression of genes delivered with a particle-mediated system was evaluated in rabbits inoculated with cottontail rabbit papillomavirus (CRPV) DNA. The optimal delivery force for maximal gene expression in rabbit skin was determined in transient beta-galactosidase assays. Forty-five sites in four rabbits were then inoculated at 350-400 p.s.i. with CRPV DNA. All sites (100%) formed papillomas with multiple papillomas at most sites. These results support the feasibility of using a particle-mediated delivery system for gene therapy and suggest that some papillomavirus features, such an origin of replication, may be well suited for use in vectors to target long term expression to skin.     

An Ustilago maydis Mutant Partially Blocked in P45014DM Activity Is Hypersensitive to Azole Fungicides

An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole.     

Isolation and characterization of a Clo DF13::Tn901 plasmid mutant with thermosensitive control of DNA replication.

After nitrosoguanidine mutagenesis, a mutant Escherichia coli strain harboring the Clo DF13::Tn901 plasmid pJN03 was isolated that is thermosensitive (Ts) for growth at 43 degrees C. The mutation responsible for this thermosensitive phenotype resides on the pJN03 plasmid genome. Cells harboring the pJN03 cop-1(Ts) plasmid mutant showed a large increase in plasmid copy number at 43 degrees C accompanied by an increase in the synthesis of plasmid-specified gene products like cloacin DF13 and beta-lactamase. The pJN03 cop-1(Ts) mutant showed uncontrolled plasmid DNA replication at the nonpermissive temperature. Analysis of plasmid deletions showed that the mutation is located in the Clo DF13 map interval from 0 to 12% or 29 to 45%. This implies that native cloacin DF13 and the Clo DF13-specified polypeptides B, C, D, E, and G are not involved in the pleiotropic phenotype of the plasmid mutant pJN03 cop-1(Ts).     

The isolation of Saumarez Reef virus, a new flavivirus, from bird ticks Ornithodoros capensis and Ixodes eudyptidis in Australia.

Strains of a new flavivirus, for which the name Saumarez Reef Virus is proposed, were isolated from seabird ticks collected from four localities. Two strains were isolated from ticks of the species Ornithodoros capensis Neumann 1901 collected from the nests of Sooty Terns, Sterna fuscata Linnaeus 1766 on coral cays off the east coast of Queensland, Australia. The other three strains were isolated from ticks of the species Ixodes eudyptidis Maskell 1885 taken from two dead Silver Gulls Larus novaehollandiae Stephens 1826 in northern Tasmania. The new virus was compared serologically with 50 other flaviviruses at the Yale Arbovirus Research Unit and was found to be most closely related to Tyuleniy virus.     

Use of Transposons in Cloning Poorly Selectable Genes of Escherichia coli: Cloning of uvrA and Adjacent Genes

A transposon was introduced close to a poorly selectable gene. This gene could be cloned by using selection for the antibiotic resistance marker of the transposon.     

Hexazonium pararosaniline as a fixative for animal tissues

Hexazonium pararosaniline is a valuable reagent that has been used in enzyme activity histochemistry for 50 years. It is an aqueous solution containing the tris-diazonium ion derived from pararosaniline, an aminotriarylmethane dye, and it contains an excess of nitrous acid that was not consumed in the diazotization reaction. Other investigators have found that immersion for 2 min in an acidic (pH 3.5) 0.0015 M hexazonium pararosaniline solution can protect cryostat sections of unfixed animal tissues from the deleterious effects of aqueous reagents such as buffered solutions used in immunohistochemistry, while preserving specific affinities for antibodies. In the present investigation hexazonium pararosaniline protected lymphoid tissue and striated muscle against the damaging effects of water or saline. The same protection was conferred on unfixed sections treated with dilute nitrous or hydrochloric acid in concentrations similar to those in hexazonium pararosaniline solutions. Model tissues (solutions, gels or films containing gelatin and/or bovine albumin) responded predictably to well known cross-linking (formaldehyde) or coagulant (mercuric chloride) fixatives. Hexazonium pararosaniline solutions prevented the dissolution of protein gels in water only after 9 or more days of contact, during which time considerable swelling occurred. It is concluded that there is no evidence for a “fixative” action of hexazonium pararosaniline. The protective effect on frozen sections of unfixed tissue is attributable probably to the low pH of the solution.