Genetic characterization by fluorescent AFLP of Pseudomonas savastanoi pv. savastanoi strains isolated from different host species

The genetic diversity of 71 Pseudomonas savastanoi pv. savastanoi strains isolated from different host species and from diverse geographical regions was determined by fluorescent amplified fragment length polymorphism (f-AFLP) analysis. The study was carried out using three different selective primer combinations. Strains of P. syringae pv. syringae , P. syringae pv. phaseolicola , P. syringae pv. glycinea , P. syringae pv. tagetis and P. amygdali were also included as outgroups. Based on cluster analysis of f-AFLP data, all P. savastanoi pv. savastanoi strains showed a high degree of similarity, grouping in a cluster and forming a taxon clearly separate from outgroup strains. AFLP analyses failed to support placing strains of P. savastanoi pv. savastanoi , P. syringae pv. phaseolicola and P. syringae pv. glycinea in the same species. Strains of P. savastanoi pv. savastanoi formed subclusters that correlated with the host species. Strains identified within these subclusters were related to the geographical region where the strains were isolated. Strains of P. savastanoi pv. savastanoi from olive were divided into two subclusters. Strains from oleander were differentiated from those from ash and were divided into two additional subclusters, distinct from olive strains. Three strains isolated from jasmine showed a high level of similarity among them but, at a lower Dice similarity coefficient, were linked to a subcluster including olive strains. Finally, two strains isolated from privet were similar to strains from olive and were included in the same subcluster.     

Effects of thyroxine and growth hormone treatment of dairy cows on milk yield, cardiac output and mammary blood flow

Four cows received thyroxine injections (T4; 20 mg/d) and three cows received growth hormone injections (GH; 44 mg/d) for 4 d during successive 16-d experimental periods. Measurement was made of milk yield, protein yield, mammary tyrosine and phenylalanine uptake, blood plasma hormone concentrations, mammary blood flow and cardiac output. Milk yield increased by 25% with T4 and 21% with GH treatment. Milk protein content tended to decline during T4 treatment and increase following GH treatment. Cardiac output increased by 8.9 liter/min (20%) and 4.6 liter/min (10%) with T4 and GH injection. Mammary blood flow (half-udder) increased from 3.6 to 4.9 liter/min (35%) and from 3.3 to 4.4 liter/min (33%) with T4 and GH treatment, respectively. These increases calculated on a whole-udder basis, accounted for 28% (T4) and 48% (GH) of the increases in cardiac output. The proportion of cardiac output perfusing the (whole) udder increased to 19.1% (T4) and 18.7% (GH), increases of 17 and 30%, respectively. Heart rate increased with T4 (but not GH treatment) from 80 to 115/min. Ratio of blood flow to milk yield was not changed by either treatment. The proportion of cardiac output perfusing the udder likely plays a major role in facilitating the partitioning of nutrients for milk synthesis.     

Conservation assessment of British limestone pavements based on floristic criteria

The total British area of limestone pavement is very small, yet this scarce resource is being destroyed to supply decorative stone. Its scientific interest is both geological and botanical. Exploiting an exhaustive survey, a weighted index was developed for assessing the conservation value of limestone pavements based on their deep grike floras. Using weighted indices, 27 sites in Cumbria, Gwynedd, Lancashire, North Yorkshire and Skye were identified as important for the conservation of limestone pavement floras.     

Inhibition of telomerase in canine cancer cells following telomestatin treatment

Telomere shortening in normal somatic cells has been proposed as a major barrier to unlimited cellular proliferation. Telomerase is an enzyme capable of maintaining telomere length, and thus bypassing this barrier. In human beings, telomerase activity is restricted to cancer cells and cells of stem or germ cell lineages. Dogs represent a potentially useful clinical model for the development of telomerase‐based therapies because telomerase activity is also restricted to cancer cells and stem cells in this species. We examined the ability of telomestatin to inhibit telomerase activity in telomerase‐positive D17 and CMT7 canine cancer cell lines. At a concentration of 2 μM, telomestatin treatment resulted in a decrease in telomerase activity, telomere shortening, growth inhibition and apoptosis in telomerase‐positive cancer cells. These effects were not seen in telomerase‐negative skin fibroblasts or negative controls. These results confirm that telomestatin specifically inhibits telomerase activity in canine cancer cells and strengthens the usefulness of dogs as a model for testing telomerase‐based therapies.     

Microbial biomass and respiratory activity in soil aggregates of different sizes from three beechwood sites on a basalt hill

We studied the effects of aggregates of different sizes on the soil microbial biomass. The distribution of aggregate size classes (<2, 2–4, 4–10, >10 mm) in the upper mineral soil horizon (A_h layer) was very different in three sites (upper, intermediate, lower) in a beechwood (Fagus sylvatica) on a basalt hill (Germany). Aggregates of different sizes (<2, 2–4, 4–10 mm) contained different amounts of C and N but the C:N ratios were similar. C and N contents were generally higher in smaller aggregates. The maximum initial respiratory response by microorganisms in intact aggregates and in aggregates passed through a 1-mm sieve declined with the aggregate size, but the difference was more pronounced in intact aggregates. Disruption of aggregates generally increased this response, particularly in 4- to 10-mm aggregates in the lower site. Basal respiration differed strongly among sites, but was similar in each of the aggregate size classes. Aggregate size did not significantly affect the specific respiration (g O₂ g^–1 microbial C h^–1) nor the microbial: organic C ratio, but these parameters differed among sites. Microbial growth was increased strongly by passing the soil through a 1-mm sieve in each of the aggregate materials. The growth of microorganisms in disrupted aggregates was similar, and the effect of aggregate disruption depended on the growth of microorganisms in intact aggregates.