Oxidized dietary fat,alkaline phosphatase concentrations and performance in racing greyhounds

Racing dogs are often fed raw meat. Raw meat may become oxidized because it contains no preservatives but few studies have examined the effect of feeding oxidized food to dogs. This study was originally designed to determine the effect of different concentrations of dietary fat on greyhound performance. After the experiment had been completed, however, it was discovered that the peroxide values (PV) of both diets were elevated indicating that fat oxidation had been present. This study was considered to have value, therefore, because it compared performance and blood parameters in eight trained Greyhounds fed either a high fat moderately oxidized (HFMO) diet (43%ME fat with PV of 44 mEq/kg) or a medium fat highly oxidized (MFHO) diet (31%ME fat with PV of 211 mEq/kg) for 8 weeks per diet in a randomized cross‐over design. Dogs were raced over 500 m twice weekly. Race times over the last 4 weeks of each diet period and blood parameters before racing during the last week of each diet period were compared. Dogs fed the MFHO food ran 0.04 m/s slower (p = 0.06) and serum alkaline phosphatase concentrations were higher (149 vs. 56 U/L; p < 0.0001) than in dogs fed the HFMO diet. Further evaluation is needed to determine whether lower dietary fat or increased oxidation was responsible for the altered performance but oxidation of the food should be considered as one possible explanation for an increase in serum alkaline phosphatase during a diet trial.     

Mechanisms of Infertility Associated with Clinical and Subclinical Endometritis in High Producing Dairy Cattle

Clinical and subclinical endometritis are common causes of infertility and subfertility in high producing dairy cattle, delaying the onset of ovarian cyclic activity after parturition, extending luteal phases and reducing conception rates. Escherichia coli and Arcanobacterium pyogenes cause endometrial damage and inflammation. Components of microbes, such as lipopolysaccharide (LPS), are detected by Toll-like receptors on endometrial cells, leading to secretion of cytokines, chemokines and antimicrobial peptides. Long luteal phases associated with endometritis are probably caused by a switch in endometrial prostaglandin production from prostaglandin F_2a (PGF) to prostaglandin E₂. In addition, LPS impairs the function of the hypothalamus and pituitary, and directly perturbs ovarian granulosa cells steroidogenesis, providing mechanisms to explain the association between uterine disease and anovulatory anoestrus. Cows with uterine disease that ovulate have lower peripheral plasma progesterone concentrations that may further reduce the chance of conception associated with endometritis.     

Clustering mutational spectra via classification likelihood and markov chain monte carlo algorithms

We have analyzed a set of 39 mutational spectra of the supF gene that were generated by different mutagenicagents and under different experimental conditions. The clusteranalyses was performed using a newly developed clustering procedure. The clustering criterion used in the procedure was developed by applying the classification likelihood approach to multinomial observations. We also developed a Gibbs sampling-based optimization procedure that outperformed previously developed methods in a comparative simulation study The results of the cluster analysis showed that our clustering procedure was able to recreate natural grouping of the mutational spectra with respect to the characteristics of mutagenic agents used to generate them and with respect to experimental conditions applied in the process of generating spectra. These results are an important confirmation of the relevance of mutational spectra in characterizing mutagenic mechanisms of different carcinogens.     

A 10-year record of the weathering rates of surficial pebbles in Kärkevagge, Swedish Lapland

Between 1999 and 2004, nylon mesh bags containing  6.2 mm diameter fragments of crushed dolomite or granite were exposed to weathering on the surfaces of birch, Dryas heath, heath, meadow, solifluction meadow, and willow vegetation communities in Kärkevagge, a glaciated trough in Swedish Lapland. The material in the bags had previously been in the same locations from either 1994 or 1995 when it had been placed in the field as freshly crushed pebbles. Results of the mass losses resulting from chemical weathering during the first 4- or 5-year period were reported in Dixon et al. [Dixon, J.C., Thorn, C.E., Darmody, R.G., Schlyter, P. 2001. Weathering rates of fine pebbles at the soil surface in Kärkevagge, Swedish Lapland. Catena 45, 273–286.] in Catena. The spatial results of the second 5-year period confirm those determined during the first period. In general, wetter, more acidic sites promoted greater losses from the dolomite, but the losses from the granite were too small to reveal distinctive spatial patterns. Dolomite consistently weathered faster than granite in at-a-site comparisons with total mass losses between 1999 and 2004 ranging from 1.90% to 9.98% for dolomite and − 0.07% to 4.02% for granite. Spatial distinctions were blurred during the second period due to significant losses of bags at dry sites from atmospheric exposure. However, at-a-site comparisons between the two study periods revealed statistically significantly greater losses during the second period when compared to the first. In the absence of appropriate ground climate data, it is worth noting that air climates were both warmer and wetter during both study periods when compared to the 1961–1990 averages, and the second 5-year study period was also warmer and wetter than the first.     

The Rhizofiltration of Sodium from Hydroponic Fluid using Scented Geraniums

The ability of two scented geraniums, Pelargonium sp. `Frensham' and Pelargonium sp. `Citrosa' to tolerate and accumulate salt was assessed in a hydroponic system under greenhouse conditions. Rooted cuttings were exposed to a range of salt concentrations (0 to 200 mM NaCl) over a two-week period. No visible signs of phytotoxicity were observed on scented geranium plants grown in solutions up to 100 mM sodium chloride. Tolerance to salt exposure was assessed with chlorophyll a fluorescence parameters. A significant decline in the efficiency of the photosystem (Fv/Fm) was observedin Frensham plants exposed to 200 mM NaCl for 14 days. The numberand size of active reaction centers (Fv/Fo) declined with increasing NaCl treatments in both species. Total chlorophyll content of both species decreased with increasing salt treatmentas a result of significant reductions in the chlorophyll acontent. At higher levels of sodium chloride treatment, salt extrusion was observed on the petioles and the leaf lamina. An accumulation in excess of 3.7 and 2.6% of the dry weight of Frensham plants as sodium was observed in shoots and roots, respectively. The effect of the accumulated sodium on the physiology of scented geraniums was assessed through biochemicalanalysis. The determination of amino nitrogen and stress-relatedmarkers revealed an initial increase in 4-aminobutyrate, proline,asparagine, glutamine, and alanine in the root tissues. Shoot analysis showed gradual increases in asparagine, aspartate, andalanine. These data provide the first evidence for the salt tolerating and accumulating potential of Pelargonium sp. and demonstrate the efficacy of this plant species for the remediation of salt contaminated hydroponic solutions.     

Estimating the global potential of forest and agroforest management practices to sequester carbon

Forests play a prominent role in the global C cycle. Occupying one-third of the earth's land area, forest vegetation and soils contain about 60% of the total terrestrial C. Forest biomass productivity can be enhanced by management practices, which suggests that, by this means, forests could store more C globally and thereby slow the increase in atmospheric CO₂. The question is how much C can be sequestered by forest and agroforest management practices. To address the question, a global database of information was compiled to assess quantitatively the potential of forestry practices to sequester C. The database presently has information for 94 forested nations that represent the boreal, temperate and tropical latitudes. Results indicate that the most promising management practices are reforestation in the temperate and tropical latitudes, afforestation in the temperate regions, and agroforestry and natural reforestation in the tropics. Across all practices, the median of the mean C storage values for the boreal latitudes is 16 tCha[^?1 (n=46) while in the temperate and tropical latitudes the median values are 71 tCha^?1 (n=401) and 66 tCha^?1 (n=170), respectively. Preliminary projections are that if these practices were implemented on 0.6 to 1.2×10⁹ ha of available land over a 50-yr period, approximately 50 to 100 GtC could be sequestered.