Identification of an cysteine-to-arginine substitution caused by a single nucleotide polymorphism in the canine monoamine oxidase B gene

Monoamine oxidase B catalytically oxidizes biogenic amines such as phenylethylamine and dopamine, and its activity is presumed to be related to particular behavioral traits. In this study, we first identified a single nucleotide polymorphism (T199C) located on the putative third exon of the canine monoamine oxidase B gene, which causes an amino acid substitution from cysteine to arginine. We then examined the allelic frequencies in five dog breeds (Golden Retriever, Labrador Retriever, Maltese, Miniature Schnauzer, and Shiba) and found significant variation among them. The present results suggest that analysis of the monoamine oxidase B polymorphism could be a useful means of elucidating the genetic background of breed-specific behavioral characteristics in dogs.     

Interaction between salsolinol (SAL) and thyrotropin-releasing hormone (TRH) or dopamine (DA) on the secretion of prolactin in ruminants

We have recently demonstrated that salsolinol (SAL), a dopamine (DA)-derived compound, is present in the posterior pituitary gland and is able to stimulate the release of prolactin (PRL) in ruminants. The aim of the present study was to clarify the effect that the interaction of SAL with thyrotropin-releasing hormone (TRH) or DA has on the secretion of PRL in ruminants. A single intravenous (i.v.) injection of SAL (5mg/kg body weight (b.w.)), TRH (1microg/kg b.w.), and SAL plus TRH significantly stimulated the release of PRL in goats (P<0.05). The cumulative response curve (area under the curve: AUC) during 120min was 1.53 and 1.47 times greater after the injection of SAL plus TRH than either SAL or TRH alone, respectively (P<0.05). A single i.v. injection of sulpiride (a DA receptor antagonist, 0.1mg/kg b.w.), sulpiride plus SAL (5mg/kg b.w.), and sulpiride plus TRH (1microg/kg b.w.) significantly stimulated the release of PRL in goats (P<0.05). The AUC of PRL during 120min was 2.12 and 1.78 times greater after the injection of sulpiride plus TRH than either sulpiride alone or sulpiride plus SAL, respectively (P<0.05). In cultured bovine anterior pituitary (AP) cells, SAL (10(-6)M), TRH (10(-8)M), and SAL plus TRH significantly increased the release of PRL (P<0.05), but the additive effect of SAL and TRH detected in vivo was not observed in vitro. In contrast, DA (10(-6)M) inhibited the TRH-, as well as SAL-induced PRL release in vitro. All together, these results clearly show that SAL can stimulate the release of PRL in ruminants. Furthermore, they also demonstrate that the additive effect of SAL and TRH on the release of PRL detected in vivo may not be mediated at the level of the AP, but that DA can overcome their releasing activity both in vivo and in vitro, confirming the dominant role of DA in the inhibitory regulation of PRL secretion in ruminants.     

Hypoglycemia associated with disseminated metastatic tonsillar squamous cell carcinoma producing insulin‐like growth factor‐I in a Pomeranian dog

A 13‐year‐old spayed female Pomeranian dog was presented for persistent, severe hypoglycemia (37 mg/dL; reference interval [RI] 75‐128 mg/dL). Progressive nonregenerative anemia (hematocrit 23.3%‐15.9%; RI 37.0%‐55.0%) and severe thrombocytopenia (36 000/µL; RI 200‐500 000/µL) were also noted. The serum insulin concentration was low (0.24 ng/mL; RI 0.302‐1.277 ng/mL). Computed tomography revealed multiple splenic nodules (1‐6 mm in diameter) and several hepatic nodules (7.6, 12 mm in diameter). Ultrasound‐guided fine‐needle aspiration of the splenic and hepatic nodules revealed low numbers of epithelial cells with mild cellular atypia, suggestive of a metastatic epithelial tumor, but the primary site was unknown at that time. On careful oral examination under general anesthesia, an enlarged right tonsil was noted grossly, and histopathologic examination of the tonsil diagnosed squamous cell carcinoma. Bone marrow aspirates and biopsies of the splenic and hepatic nodules were performed; all samples were diagnosed as metastatic carcinoma on histopathologic examination. No nodules were present in the pancreas, despite careful palpation during exploratory laparotomy. On immunohistochemistry, the neoplastic cells were positive for cytokeratin AE1/3 and insulin‐like growth factor (IGF)‐I but were negative for chromogranin A, PGP9.5, insulin, and inconclusive for IGF‐II. This is the first report of a primary IGF‐I‐producing squamous cell carcinoma in the tonsil of a dog with metastases to bone marrow, liver, and spleen, resulting in hypoglycemia.     

Production of asexual and sexual offspring in the triploid sexual planarian Dugesia ryukyuensis

Certain freshwater planarians reproduce asexually as well as sexually, and their chromosomal ploidies include polyploidy, aneuploidy and mixoploidy. Previously, we successfully performed an experiment in which a clonal population produced by asexual reproduction of the Dugesia ryukyuensis (OH strain) switched to the sexual mode of reproduction. Worms of this strain are triploid with a pericentric inversion on Chromosome 4. The worms were switched to sexual reproduction after being fed with sexually mature Bdellocephala brunnea, which is a sexually reproducing species. The resulting sexualized OH strain produced cocoons filled with several eggs. Two putative factors, Mendelian factor(s) and chromosomal control(s), have been proposed as determining the reproductive mode. The present study demonstrated that inbreeding of the resultant sexualized worms produced the following four types of offspring through sexual reproduction: diploid asexual worms, triploid asexual worms, diploid sexual worms and triploid sexual worms. The chromosomal mutation on Chromosome 4 was inherited by these offspring independent of their reproductive mode. These results provide two important pieces of information: (i) the putative genetic factor was not necessarily inherited in a Mendelian fashion; and (ii) the reproductive mode is not regulated by chromosomal changes such as polyploidy or chromosomal mutations. This suggests that asexuality in D. ryukyuensis is regulated by an unknown factor(s) other than a Mendelian factor or a chromosomal control.     

Rice bran fractions improve blood pressure, lipid profile, and glucose metabolism in stroke-prone spontaneously hypertensive rats

Effect of dietary supplementation of two types of rice bran fraction on blood pressure (BP), lipid profile, and glucose metabolism in stroke-prone spontaneously hypertensive rats was studied. Male 4-week-old rats were divided into one group fed the AIN-93M-based control (C) diet and two groups fed diet supplemented with 60 g/kg of Driselase and ethanol fractions (DF and EF, respectively) of rice bran. After 8 weeks feeding, the BP decreased in the DF and EF groups in comparison with the C group (p < 0.01). Plasma ACE inhibitory activity, BUN, BUN/creatinine ratio, albumin, triglyceride, and glucose levels were lower in the DF and EF groups than in the C group (p < 0.01). Plasma nitric oxide and urinary 8-hydroxy-2'-deoxyguanosine levels were lower in the DF and EF groups than in the C group (p < 0.01). Rice bran fractions appear to have a beneficial dietary component that improves hypertension, hyperlipidemia, and hyperglycemia.     

Construction of a linkage map for watermelon (Citrullus lanatus (Thunb.) Matsum & Nakai) using random amplified polymorphic DNA (RAPD)

Summary A linkage map for watermelon (Citrullus lanatus) was constructed on the basis of RADP, ribosomal DNA restriction fragment length polymorphism (RFLP), isozyme, and morphological markers using F₁BC1. A segregating population of 78 individuals was the result of a backcross of a cultivated inbred line (H-7; Citrullus lanatus; 2n=22) and a wild form (SA-1; C. lanatus; 2n=22), in which the latter was the recurrent (male) parent. A total of 69 RAPD, one RFLP, one isozyme, and three morphological markers was found to segregate in the BC1 population. Linkage analysis revealed that 62 loci could be mapped to 11 linkage groups that extended more than 524 centimorgans (cM), while 12 loci segregated independently of all other markers. The locus for exocarp color was linked to two RAPD markers within a region of 5 cM on linkage group 4. The locus for flesh color was linked to a RAPD marker within a region of 30 cM on linkage group 6. The isozyme marker GOT was located on the linkage group 1. Linkage group 2 contained a locus for ribosomal DNA within 5 cM of a RAPD marker. Half of the RAPD markers on the linkage group 7 displayed severely distorted segregation. The construction of linkage map using molecular markers is necessary for the breeding of watermelon to introduce useful gene of wild watermelon efficiently. However the linkage map that was constructed for the most part on the basis of RAPD markers could not cover significant parts of the genome, the linkage map provides breeders of watermelons the possibility of tagging useful agronomic traits, as well as the gene for exocarp color.Abbreviations RAPD random amplified polymorphic DNA - RFLP restriction fragment length polymorphism - GOT glutamate oxaloacetate transaminase - MDH malate dehydrogenase - ACP acid phosphatase - 6PGH 6-phosphogluconate dehydrogenase     

The effects of acute exposure to deoxynivalenol on some inflammatory parameters in miniature pigs

Seven miniature pigs were injected intravenously with deoxynivalenol (DON) at 1 mg/kg body weight; afterward, the number of leukocytes in peripheral blood, the luminol-dependent chemiluminescence of neutrophils, the serum or plasma concentration of cytokines and acute-phase proteins were evaluated to determine the effects of acute exposure to DON on inflammatory responses. White blood cell counts were transiently increased at 3, 6, and 12 hr post-injection (PI) due to the increased number of neutrophils. The luminol-dependent chemiluminescence value of neutrophils was significantly elevated at 24 hr PI, indicating the activation of the bactericidal function of neutrophils. Significant increases of interleukin (IL)-8 and tumor necrosis factor-α at 3 hr PI and IL-6 at 6 hr PI were detected in the serum. The concentration of haptoglobin and serum amyloid A was significantly increased at 24 hr PI. These results suggest that acute exposure to DON induced a temporary recruitment of neutrophils in the peripheral blood by IL-8 and subsequent activation of the bactericidal function, and a transient increase of proinflammatory cytokines and acute-phase proteins, indicating the immunomodulatory effects of DON in pigs.