Barriers as boundaries for metapopulations and demes of Peromyscus leucopus in farm landscapes

Effects of potential barriers (roads and cultivated fields) on both demographic and genetic features of subpopulations of white-footed mice were studied near Ottawa, Canada. Live trapping, colored bait and track registry were used to study animal movements across roads on four 1.44 ha areas each within a small forest bisected by a narrow gravel road. The genetic study was done in 11 other forest fragments separated from each other by cultivated fields. Frequencies of three electrophoretic variants of salivary amylases were established for mice caught in each patch of wood and genetic similarity of subpopulations was calculated. Movements of mice across the roads were very infrequent (quantitative barrier), although movements adjacent to roads were frequent and long enough to cross the roads. Salivary amylase data showed that studied subpopulations were genetically very similar although the sample was intentionally biased toward demographic isolation. Results are discussed in terms of possible hierarchical relationships of metapopulations and genetic demes in the context of landscape ecology, management and conservation practice.     

A dog with acute myelomonocytic leukemia

A three-year-old dog with marked leukocytosis, lymphadenopathy, and diarrhea showed an increase in unidentified blasts in the peripheral blood, and they were proliferated in the bone marrow. The dog was diagnosed with myelomonocytic leukemia (M4) because the blast cells were demonstrated by cytochemical staining to be both myeloid and monocytic cells. Although the dog was treated with a multi-combination chemotherapy and induction therapy using vitamin K2, it died on day 47 after the first admission. This case is the first report of M4 in Japan.     

Characterization of canine platelet activation induced by platelet activating factor (PAF)

Characteristics of the signal transduction in Platelet activating factor (PAF)-activated platelets and effects of anti-platelet agents on this response were investigated in vitro for potential therapeutic applications in canine endotoxemia. Blockade of the PAF receptor by a specific blocker has the strongest inhibitive effect on the PAF-induced platelet reactions. The response was also inhibited by either Ca(2+) channel blockers or prostaglandin E(1).     

The effect of small interfering RNA (siRNA) against the Bcl-2 gene on apoptosis and chemosensitivity in a canine mammary gland tumor cell line

The aim of this study was to investigate whether downregulation of Bcl-2 expression by small interfering RNA (siRNA) against the canine Bcl-2 gene would enhance the apoptosis and sensitivity of a canine mammary gland tumor cell line (CF33) to doxorubicin. Transfections of CF33 with siRNA were performed using cationic liposomes. Sequence-specific downregulation of Bcl-2 expression was measured by semiquantitative RT-PCR and Western blot analysis. Total viable cells were determined by MTS assay and apoptotic cell rates were determined by the immunohistochemical analysis on ssDNA. Our data showed the siRNA downregulated Bcl-2 expression which increased apotosis and also increased the sensitivity of CF33 to doxorubicin. This study indicated that downregulation of Bcl-2 expression by siRNA would be useful as a new protocol to increase the effect of doxorubicin on treatment of canine mammary gland tumors, requiring a detailed evaluation of siRNA in vivo.     

Diversity and population density of methanogens in the large intestine of pigs fed diets of different energy levels

Marker gene analysis was performed to assess the effect of energy level on the diversity and population density of methanogens in pig fecal material. Crossbred pigs were fed high or low energy level diets, a high‐energy (HE) diet that satisfied daily gain at 1.2 kg, and a low‐energy (LE) diet with amount of 0.6 times of the HE diet. Growth performance and short‐chain fatty acid in feces were examined. Diversity of methanogen was analyzed by the α‐subunit of methyl coenzyme‐M reductase gene (mcrA) clone library from fecal DNA. The DNA copy numbers of mcrA were quantified by real‐time PCR. There was no difference in the concentration and composition of short‐chain fatty acid between treatments. Differences in the mcrA clone library were observed between HE and LE treatments (p < 0.05). Ninety‐five percent of cloned sequence affiliated genus Methanobrevibacter in the feces of the pig regardless of treatments. During the experimental period, no significant difference in the proportion of copy numbers of mcrA against that of 16S rRNA gene of total bacteria was observed between treatments. In conclusion, feeding energy level affected composition of methanogens in the large intestine of the pig, while population density of methanogen was not affected.     

One-step immunochromatography assay for detection of high-level canine serum trypsin-like immunoreactivity

We developed a one-step immunochromatography assay kit to measure high levels of canine trypsin-like immunoreactivity (cTLI) for bedside estimation of canine pancreatitis. The serum cTLI level can be determined within 10 min by visual comparison of color strengths in the test and reference zones. The serum cTLI levels determined by this method correlate well with canine TLI-ELISA and can be classified into 3 categories: cTLI levels higher than 60 ng/ml were considered positive; 20-60 ng/ml, weakly positive; and less than 20 ng/ml, negative. Twelve dogs suspected of pancreatitis were examined using this method; 4 dogs were positive, 2 were weakly positive, and 6 were negative. This test can detect a high level of serum cTLI and a positive result in the TLIH test will provide critical information for evaluation of pancreatitis in dogs.     

Effect of using subirrigation and slit tillage to increase soybean (Glycine max) yield in clayey soils in rice paddies converted to uplands

Water stress reduces soybean (Glycine max) yield in fields converted from clayey-soil rice (Oryza sativa) paddies to uplands (upland converted paddies [UCPs]). Subirrigation and/or allowing roots to penetrate to a deeper soil layer were expected to effectively mitigate water stress. Therefore, we examined the effects of subirrigation and slit tillage on mitigating water stress in clayey soils (52% clay) in UCPs. Four treatment experiments (subirrigation, slit tillage, subirrigation control, and slit tillage control) were conducted in each of three growing seasons, with sampling for yield analysis conducted in triplicate. Following conventional tillage, a slit tillage blade was used to cut 15-mm-wide vertical slits in the surface of the soil (cutting depth = 15–20 cm) and seeds were sown 15 mm from the cut lines. Subirrigation then occurred for approximately 21–47 days, from the end of the rainy season, when water table elevation was at 35 cm below ground. We found that subirrigation only resulted in improved soybean yield in 2012, when precipitation after the flowering stage was low, whereas slit tillage significantly increased yield in all three growing seasons, including a particularly wet growing season. Overall, subirrigation and slit tillage increased soybean yield by 2% and 13%, respectively. Slit tillage also resulted in a significantly greater taproot length and root density. Stomatal conductance at midday in about the R5–6 stages was higher in slit-tilled plots than in control plots, but only in the subirrigated field.