Influence of Water Temperature on Morphological Deformities in Cultured Larvae of Japanese Eel,Anguilla japonica,at Completion of Yolk Resorption

The occurrence of morphological deformities under different rearing water temperatures (18, 20, 22, 24, 26, 28, and 30 C) was examined in Japanese eel larvae. The rates of hatching and survival until yolk resorption at 22–26 C were higher than those at other water temperatures. Fertilized eggs never hatched at 18 and 30 C. The rates of occurrence of abnormal larvae reared at the water temperatures 24–28 C were lower than those at 20 or 22 C. Pericardial edema and lower jaw deformities occurred most frequently at lower temperatures (20 and 22 C). In contrast, the incubation temperature did not significantly affect the relative frequency of some neurocranial deformities and of spinal curvature. These results imply that the optimal temperatures for rearing Japanese eel eggs and embryos are 24–26 C from the viewpoints of survival and deformity.     

Clearance of Theileria sergenti-infected bovine red blood cells in severe combined immune deficiency mice

Clearance of Theileria sergenti-infected bovine red blood cells (Bo-RBCs) from the blood circulation of severe combined immune deficiency (SCID) mice was studied to help understand the mechanisms of anemia developing in cattle infected with T. sergenti. For the clearance test, Bo-RBC samples having 2%, 58%, and 76% parasitemia and, as a control, parasite-free Bo-RBCs were prepared in the Bo-RBC-SCID mouse model. The T. sergenti-infected Bo-RBCs and the uninfected control Bo-RBCs were separately labeled with two, green and red, fluorescent dyes, mixed together, and injected intravenously into SCID mice. The blood samples collected at various time points were observed under a fluorescent microscope, and the numbers of green and red fluorescing RBCs were counted differentially to determine the clearance rates of T. sergenti-infected and uninfected Bo-RBCs. This test clearly demonstrated that the Bo-RBC samples having higher parasitemias were cleared faster from the blood circulation of SCID mice. The results suggest that the intravascular clearance system in SCID mice may have a mechanism by which T. sergenti-parasitized and non-parasitized Bo-RBCs are recognized and cleared differentially.     

In vitro polyploidization of Mecardonia tenella, a native plant from South America

Mecardonia tenella is an herbaceous plant widely distributed in the temperate region of South America. Both plant architecture and flower size are characteristics that can be improved to become a viable new ornamental plant. Chromosome doubling by the use of agents such as colchicine is an available methodology to this end. Nodal segments from in vitro grown plants of M. tenella were submerged in the following doses of colchicine in 1% (v/v) dimethyl-sulfoxide (DMSO) solution (%, v/v): 0.0, 0.001 and 0.01 (24 and 48 h). The DNA content of the regenerated plants was measured by flow cytometer. A total of 68 tetraploid plants were detected out of 126 colchicine treated plants. The flowers and leaves of the tetraploid plants were bigger compared to those from the wild diploid type (control). Under field conditions, the selected tetraploid plants showed a more compact shape than the control plants.     

Gentian mosaic virus: A New Species in the Genus Fabavirus

ABSTRACT A viral isolate, designated N-1 and obtained from a gentian (Gentiana scabra) plant that exhibited mosaic symptoms, was transmitted mechanically to nine plant species in six families. These plants are known as hosts of fabaviruses. The N-1 isolate was composed of isometric particles 30 nm in diameter and included two RNA molecules of approximately 6.0 and 3.6 kb in length, as estimated by agarose gel electrophoresis. The RNAs were encapsidated separately in two of the three types of particle. Each particle contained two distinct proteins with Mr values of 39.3 x 10(3) and 26.6 x 10(3), as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Analysis of complete nucleotide sequences of the RNAs suggested that each encoded a single large polyprotein, in which putative functional proteins were arranged in a manner similar to those in Broad bean wilt virus 1 (BBWV-1) and Broad bean wilt virus 2 (BBWV-2), which are members of the genus Fabavirus (family Comoviridae). Analysis of the deduced amino acid sequences of the proteins indicated that those of isolate N-1 shared 38 to 66% identity with those of BBWV-1 and BBWV-2 but only 16 to 42% identity with those of a comovirus, Cowpea mosaic virus. Phylogenetic analysis, based on the amino acid sequences of RNA polymerase, placed isolate N-1 in a separate lineage from BBWV-1 and BBWV-2. In indirect-enzyme-linked immunosorbent assay, isolate N-1 exhibited distant serological relationship to BBWV-1, BBWV-2, and Lamium mild mosaic virus, another fabavirus. Our results suggest that N-1 represents a new species of Fabavirus. We propose the name Gentian mosaic virus for this new species.     

Oral administration of IL-1 beta enhanced the proliferation of lymphocytes and the O(2)(-) production of neutrophil in newborn calf

Recently, we demonstrated the presence of IL-1 beta in the colostral whey from dairy cows. Here, authors examined oral transmission of colostral IL-1 beta and its immunological effects on the neonatal calves. Biotin-labeled recombinant bovine (rb) IL-1 beta was administered orally to newborn calves and monitored in the serum. The results disclosed the passive transfer of colostral cytokines via the oral route, and a potent increase in white blood cell (WBC) count was observed in all calves administered with rbIL-1 beta. Oral administration of IL-1 beta significantly increased the proliferation of peripheral blood mononuclear cells (PBMCs) stimulated with concanavalin A, and the O(2)(-) production of stimulates neutrophils in newborn calves. These results suggest that the oral administration of IL-1 beta has an immunostimulatory activity in the newborn calf.     

Efficacy of atovaquone against Babesia gibsoni in vivo and in vitro

The therapeutic efficacy of atovaquone against Babesia gibsoni was examined in three dogs experimentally infected with B. gibsoni isolated from naturally infected dogs in Aomori Prefecture, Japan. Once parasitemia reached 10%, atovaquone was administered orally (30 mg/kg twice daily for 7 days). Within 2 days of atovaquone treatment, the parasite disappeared from blood smears without any clinical side effects. Anemia and thrombocytopenia were significantly improved in all the dogs. However, a polymerase chain reaction assay revealed that a B. gibsoni marker gene was intermittently present in peripheral blood after atovaquone therapy, indicating that the organism had not been eliminated, and parasites reappeared in blood smears 33 days after the last treatment. To investigate the change in sensitivity against atovaquone, an in vitro sensitivity test was performed using peripheral blood obtained from an untreated dog that was infected with the original parasite isolate, and from two of the experimentally infected and atovaquone-treated animals (blood was collected at the time of the post-treatment recurrence of the B. gibsoni infection). Atovaquone was added to the culture medium to final concentrations of 0.1, 1, 10, 100, and 1000 nM. For the untreated parasites, complete growth inhibition occurred at 1000 nM of atovaquone, whereas the recurrent parasites were inhibited by only 39.52 +/- 8.34% and 31.31 +/- 8.14% at this concentration after 48 h of incubation. Thus, the recurring parasites were less sensitive to atovaquone than the untreated originally isolated parasites.     

Activation with ethanol improves embryo development of ICSI-derived oocytes by regulation of kinetics of MPF activity

Developmental potential of bovine embryos that are not artificially activated after intracytoplasmic sperm injection (ICSI) is generally very low. In this study, we investigated effects of artificial activation with ethanol on kinetics of maturation promoting factor (MPF) activity (p34(cdc2) kinase activity) and development of bovine oocytes following ICSI. Treatment of oocytes with ethanol at 4 h after ICSI improved their first cleavage and further preimplantation development (51% vs. 13%, 14% vs. 4%: treatment with vs. without ethanol, respectively). MPF activity of oocytes was lowered until at least 2 h after ICSI. In oocytes without activation after ICSI, MPF activity temporarily elevated at 6 h after ICSI, whereas this phenomena was not observed in the oocytes treated with ethanol. Furthermore, MPF activity was elevated 20 h after ICSI in oocytes activated with ethanol, whereas this elevation of MPF activity was not shown in oocytes without activation. These results indicate that the stimulus of sperm was sufficient to lower MPF activity of oocytes following ICSI, and moreover the activation treatment of bovine oocytes with ethanol after ICSI served to maintain the low levels of MPF activity until the next cell cycle started.     

ELISA for bovine interleukin-1 receptor antagonist and its application to mastitic sera and whey

A sandwich ELISA for the bovine IL-1 receptor antagonist (bIL-1ra) was developed using recombinant (r) bIL-1ra produced by Escherichia coli, anti-rbIL-1ra rabbit IgG, its biotinylated one and avidin-peroxidase. This ELISA system enabled detection of rbIL-1ra at a concentration of more than 2 ng/ml. This ELISA was applied to quantitation of bIL-1ra in sera and whey of mastitic and healthy cows. The results indicate that although IL-1ra levels in healthy and mastitic sera and whey were comparable, serum IL-1ra/IL-1beta ratio of euthanized cows was significantly lower than that of the recovered.     

Detection of Borna disease virus in a pregnant mare and her fetus

A pregnant mare showing pyrexia, reduced appetite, ataxia and paresis was euthanized and examined for the presence of Borna disease virus (BDV). Her brain, showing multiple neuronal degeneration and necrosis with hemorrhage, and the histologically normal brain of the fetus were both positive for BDV RNA. The BDV nucleotide sequences were identical in the mare and fetus in the second open reading frame (ORF). This is the first report of the possible vertical transmission of BDV in a horse.