Confirmation of nitrogen fixation in two tropical grasses by 15N2 incorporation

Intact soil cores containing plants of Paspalum notatum or Digitaria decumbens were selected with the acetylene reduction method, and then exposed to ¹⁵N₁₅ to confirm nitrogen fixation in tropical grass-bacteria associations. In a preliminary experiment with P. notatum¹⁵N₂ incorporation was slow but progressive during 24 h in roots but translocation to rhizomes and leaves ceased after 17h. With improved assay chambers, enrichments of 0.151 and 0.563 ¹⁵N atom % excess were obtained in roots of D. decumbens cv transvala and P. notatum systems respectively, after 3 days. Enrichments in rhizomes were similar to those of roots; however in the leaves only 8% of root enrichment was observed. The addition of sucrose to the soil doubled N₂-fixation in roots in both grass species studied, but did not result in increased incorporation into the leaves of P. notatum.     

The spleen morphophysiology of fruit bats

Spleen is one of the important lymphoid organs with wide variations of morphological and physiological functions according to species. Morphology and function of the spleen in bats, which are hosts to several viral strains without exhibiting clinical symptoms, remain to be fully elucidated. This study aims to examine the spleen morphology of fruit bats associated with their physiological functions. Spleen histological observations were performed in three fruit bats species: Cynopterus titthaecheilus (n = 9), Rousettus leschenaultii (n = 3) and Pteropus vampyrus (n = 3). The spleens of these fruit bats were surrounded by a thin capsule. Red pulp consisted of splenic cord and wide vascular space filled with blood. Ellipsoids in all three studied species were found numerously and adjacent to one another forming macrophages aggregates. White pulp consisted of periarteriolar lymphoid sheaths (PALS), lymphoid follicles and marginal zone. The lymphoid follicle contained a germinal centre and a tingible body macrophage that might reflect an active immune system. The marginal zone was prominent and well developed. This study reports some differences in spleen structure of fruit bats compared to other bat species previously reported and discusses possible physiological implications of the spleen based on its morphology.     

Influence of moisture content on the vibrational properties of hematoxylin-impregnated wood

The vibrational property of hematoxylinimpregnated wood was investigated from the aspect of moisture content dependence. The specific dynamic Young's modulus (E/) and loss tangent (tan) of hematoxylin-impregnated wood were determined in the relative humidity (RH) range of 0%–97%, and were compared with those of the untreated and some conventional chemically treated woods. The changes in theE/ and tan of wood with increasing RH were suppressed by acetylation and formaldehyde treatment because of a marked reduction in the hygroscopicity of the wood. Although the hematoxylin impregnation did not significantly affect the hygroscopicity of the wood, its influence onE/ and tan were similar to that of formaldehyde treatment at low RH and of acetylation at medium RH. It was supposed that at low to medium RH hematoxylin restrains the molecular motion of amorphous substances in the cell wall because of its bulkiness and rigidity. On the other hand, at high RH it seems to work as a plasticizer with adsorbed water molecules.     

Effect of supplementation with the reduced form of coenzyme Q10 on semen quality and antioxidant status in dogs with poor semen quality: Three case studies

Oxidative stress owing to an imbalance between reactive oxygen species and antioxidants, such as coenzyme Q10 (CoQ10), is a major contributor to male infertility. We investigated the effects of the reduced form of CoQ10 (ubiquinol) supplementation on semen quality in dogs with poor semen quality. Three dogs received 100 mg of ubiquinol orally once daily for 12 weeks. Semen quality, serum testosterone, and seminal plasma superoxide dismutase (SOD) activity were examined at 2-week intervals from 2 weeks before ubiquinol supplementation to 4 weeks after the treatment. Ubiquinol improved sperm motility, reduced morphologically abnormal sperm, and increased seminal plasma SOD activity; however, it had no effect on testosterone level, semen volume, and sperm number. Ubiquinol supplementation could be used as a non-endocrine therapy for infertile dogs.     

Phylogenetic relationship of Pasteurella pneumotropica isolates from laboratory rodents based on 16S rDNA sequence

A 1344 bp fragment of the 16S ribosomal DNA (rDNA) sequence was used to determine the genetic relationship of Pasteurella pneumotropica isolates from laboratory rodents. A total of 30 nucleotide sequences of P. pneumotropica, including 24 wild strains, 3 reference strains, and 3 nucleotide sequences deposited in GenBank, were examined for heterogeneity of their 16S rDNA sequences. Phylogenetic analysis based on 16S rDNA sequence discriminated 5 types of branching lineages. Of these 5 types, 3 types had significant associations with mice or rats, and 2 had significant associations with the beta-hemolytic phenotype. These results suggest that 16S rDNA sequencing of P. pneumotropica isolates demonstrates genetic heterogeneity and phylogenetic discrimination in terms of their hemolytic phenotype and host associations.     

Bowel welding technique in dogs and cats using a diode laser: an experimental study

A laser bowel welding technique for dogs and cats was developed. The bowel was pinched using a special clamp having an opening on the body developed for this experiment (LW clamp). Using the 2 different types of contact probe (blunt tip: Laser Bipolar Dissector (LBD); sharp tip: Super Scalpel Dissector (SSD)), the laser passed through the hole in the LW clamp to cut the bowels, while at the same time, sealing the cut portion. The results obtained in this study showed that the optimum laser output using LBD was 6-10 W in dog and cat ileum, and 8-10 W in dog and cat colon. Optimum laser output using SSD was 6-8 W in dog ileum, 8-10 W in dog colon, 10 W in cat ileum and 6-8 W in cat colon. No marked differences were observed between ileum and colon when using either LBD or SSD. At the same power, burst pressure tended to be slightly higher with LBD than with SSD, although there were not significant differences between them. Histologically, complete sealing of the welded site was seen. Welding and cutting of bowel in dogs and cats was thus confirmed to be possible using the LW clamp in combination with LBD or SSD probes under a diode laser output of approximately 8 W for 50-80 s (400-640 J/cm). Thus, we can expect that this method is applicable to clinical veterinary medicine.     

Effects of addition of sodium lauryl sulfate on frozen-thawed canine spermatozoa

The addition of Orvus ES paste (OEP) to extender may be essential for preparing frozen dog semen. The major ingredient of OEP is sodium lauryl sulfate (SLS). In this study, we compared the effect of SLS on frozen dog semen with that of OEP. There were no significant differences between the 2-mg/ml SLS group and OEP group concerning sperm motility, viability and the percentage of viable sperm with intact acrosomes after freeze-thawing. These results suggest that the effectiveness of frozen dog semen extender containing 2 mg/ml of SLS is similar effective to that demonstrated for OEP.     

Effects of liquid nitrogen vapor sensitization conditions on the quality of frozen-thawed dog spermatozoa

The freezing conditions for preparation of frozen canine semen by the plunging method were investigated with regard to the period of sensitization in liquid nitrogen (LN2) vapor and the height from LN2, and the semen qualities after thawing were compared with those of canine semen prepared by the simple freezer method previously reported by us. In the plunging method, 9 semen straws were prepared under the same conditions, horizontally kept at 5, 7, and 10 cm above the LN2 surface in a styrene foam box for 5, 10, and 15 min, and then plunged into LN2. The semen qualities immediately after thawing were high in the 7 cm/10 min (cooling rate: -4 to -22 degrees C/min) and 10 cm/15 min groups (cooling rate: -6 to -10 degrees C/min). On comparison of frozen semen prepared by the plunging method (7 cm/10 min) with frozen semen prepared by the simple freezer method, sperm motility and viability were significantly higher for the frozen semen prepared by the plunging method. The cooling rate in freezing was higher for the simple freezer method (cooling rate: -6 to -50.9 degrees C/min) than the plunging method. Based on these findings, horizontal placement of canine semen straws above LN2 to reduce the temperature at a slow cooling rate of about -10 degrees C/min, followed by plunging into LN2 after sensitization for 10-15 min, provides good semen qualities after thawing.