The cytogenetics of domestic geese

Hybrids were produced between an African male and several Pilgrim female domestic geese. Partial karyotypes revealed a difference in the fourth largest pair of autosomal chromosomes. This chromosome pair was metacentric in the African, submetacentric in the Pilgrim, and heteromorphic in the hybrids. A similar difference between the putative wild ancestors of the African and Pilgrim breeds has been reported by others. These findings provide cytological evidence to support the traditional opinion that the African breed was derived from the Asiatic swan goose (Anser cygnoides) and the Pilgrim breed was derived from the European greylag goose (Anser anser).     

BC,Ontario taking different routes in trying to lower drug costs

Changes to pharmacare programs in British Columbia and Ontario were compared during a recent Toronto conference on the business aspects of Canadian health care. The brunt of the changes in BC are being borne by pharmaceutical companies and prescribers, while in Ontario the new program affects those who receive free drugs from the province and People and groups that rely on private health insurance.     

Influences on the antimicrobial activity of surface-adsorbed nisin

The efficacy of the antimicrobial peptide nisin was examined after adsorption to silica surfaces. Three protocols were used to evaluate nisin's activity against adhered cells ofListeria monocytogenes: bioassay usingPediococcus pentosaceous FBB 61-2 as the sensitive indicator strain; visualization and enumeration of cells by microscopic image analysis; and viability of adhered cells as determined by lodonitrotetrazolium violet uptake and crystallization. The activity of adsorbed nisin was highly dependent upon conditions of adsorption. The highest antimicrobial activity of adsorbed nisin occurred with high concentrations of nisin (1.0 mg ml^–1) and brief contact times (1 h) on surfaces of low hydrophobicity. Sequential adsorption of a second protein (-lactoglobulin or bovine serum albumin) onto surfaces consistently resulted in decreased nisin activity. These data provide direction for the development of applications to limit microbial attachment on food contact surfaces through the use of adsorbed antimicrobial peptides.     

Pine needle growth and fine structure after prolonged acid rain treatment in the subarctic

The growth and morphology of Scots pine needles were studied in a long-term acid rain experiment in the far north of Finnish Lapland. Pine trees 5 m tall of age 50–70 years were exposed, by spraying the foliage and soil from a height of 2 m, to either clean water (IC) or acidified water over the period 1985–1992, the acidification site being divided into sub-areas in which the precipitation contained two levels of either sulphuric (Sm, Sh) or nitric (Nm, Nh) acid, or both (SNm, SNh). The treatments with medium and high sulphate-S over eight consecutive years yielded a total sulphur deposition of 3·4 and 17·1 gm⁻², respectively, and those with medium and high nitrate-N a total nitrogen deposition of 1·1 and 5·9 g m⁻². Needles were collected for light and electron microscopy, growth measurements and morphometry. Growth in branch height had decreased by about 40% after 6 years of SNm or SNh treatment, and needle growth by 15% in the SNh trees as compared with the irrigated control trees (IC), although decreases were statistically significant only with respect to the non-irrigated control trees (DC). Growth of branches and needles was slightly better in the Nh treatment than in the IC group. The areas of the whole needle, the mesophyll and the phloem decreased in response to SNh treatment as compared with IC or DC, and a statistically significant decrease of about 30–40% was seen in the area of the xylem in comparison with DC. Cellular damage was observed following the acid treatments, especially with a high acid load. The damage was manifested in collapse of the cellular compartments, increases in lipid accumulations and swelling or disorganization of the protoplast. Increased vacuolization of the cytoplasm, plasmalemma irregularities and chilling-type damage to the mitochondria were also observed.