Factors Influencing the Frequency of Pregnancy Loss among Thoroughbred Mares in Hidaka,Japan

Pregnancy loss in mares is thought to be a main problem associated with reproductive efficiency. To clarify the situation of pregnancy loss in Thoroughbred mares in Japan, the occurrence of pregnancy loss before and after 35 days of gestation was investigated with 1,476 Thoroughbred mares in Hidaka, Japan, from 2007 to 2009. Pregnancy loss on days 17-35 was determined by ultrasound examination between 17 and 35 days after the last mating. Follow-up surveys were conducted between 35 days and foaling to determine pregnancy loss on day 35 until foaling in 843 of these mares. Using multiple logistic regression analysis, we assessed the influence of mare age, reproductive status, twin pregnancy reduction, body condition score (BCS), estrus type in foaling mares (foal heat or not), progesterone therapy, and endometrial cysts on pregnancy loss rates on days 17-35 and on day 35 until foaling in this population of mares. The pregnancy loss rates on days 17-35 and on day 35 until foaling were 5.8% and 8.7%, respectively. The overall pregnancy loss rate (day 17 until foaling, including parturient losses) was 14.7%. Risk factors for pregnancy loss included decrease in BCS between 17 and 35 days, <5 BCS at day 35, mating during foal heat, and endometrial cysts. In all, 14.7% of pregnancies were lost between day 17 and birth, contributing significantly to reduced reproductive efficiency in Thoroughbred mares in Japan. These observations indicate that mares should be maintained at high BCS and should be prevented from mating in foal heat to decrease the pregnancy loss rates.     

Rubisco small subunits of C4 plants,Napier grass and guinea grass confer C4-like catalytic properties on Rubisco in rice

ABSTRACT

Overexpression of Rubisco small subunit (RbcS) of C₄ plant, sorghum (sorghum bicolor) was shown to enhance the catalytic turnover rate (k _cat) of Rubisco in rice (Oryza sativa). In this study, the effects of other Rubisco small subunits of C₄ plants, Napier grass (Pennisetum purpureum) and guinea grass (Megathyrsus maximus) on kinetic properties of Rubisco in rice were studied. The expression levels of Napier grass RbcS (NgRbcS) and guinea grass RbcS (GgRbcS) proteins accounted for 41% and 45% of total RbcS, respectively in homozygous overexpression lines. The k _cat and K _m for CO₂ (Kc) of Rubisco were increased in all transgenic lines. Interestingly, the k _cat was markedly higher in NgRbcS homozygous line, whereas K _c was notably higher in GgRbcS homozygous line. Although its effects depend on species, these results suggest that the introduction of C₄ RbcS are effective approaches to alter the catalytic properties of Rubisco in rice.     

Red Algal Bromophenols as Glucose 6-Phosphate Dehydrogenase Inhibitors

Five bromophenols isolated from three Rhodomelaceae algae (Laurencia nipponica, Polysiphonia morrowii, Odonthalia corymbifera) showed inhibitory effects against glucose 6-phosphate dehydrogenase (G6PD). Among them, the symmetric bromophenol dimer (5) showed the highest inhibitory activity against G6PD.     

The Effects of Frequent Electroejaculation on the Semen Characteristics of a Captive Siberian Tiger (Panthera tigris altaica)

Artificial insemination (AI) can help to avoid inbreeding and genetic degeneration for sustaining genetically healthy populations of endangered species in captivity. Collection of a sufficient quantity of viable sperm is an essential first step in the AI process. In the present study, we examined the effects of frequent electroejaculation on semen characteristics in a Siberian tiger. We collected semen in all 17 trials during 6 breeding seasons (6 years). The mean number of sperm and the percentage of motile sperm were 294.3 ± 250.2×10⁶/ejaculate and 82.4 ± 11.4%, respectively. The number of motile sperm tended to increase during frequent electroejaculation in the same breeding season. Semen collection by electroejaculation can be performed effectively up to the fourth sequential ejaculate, which contained the most sperm in the study. In conclusion, frequent collection of sperm by electroejaculation from tigers may be effective for collection of a large number of motile sperm.     

Effects of Fiber Additives on the Desiccation Crack Behavior of the Compacted Akaboku Soil as A Material for Landfill Cover Barrier

In the daily and final landfill cover barrier system, the hydraulic properties of compacted soil liners and the strength of soil can be adversely affected by desiccation cracking, resulting in the loss of effectiveness and integrity of the containment system as a barrier. Recently, there is an interest of using fiber additive to overcome the desiccation cracking problem. In this study, the desiccation crack test was conducted to investigate the effect of fiber additive on suppressing desiccation cracks in compacted Akaboku soils. Polypropylene (C₃H₆) fiber was used as an additive material for soil sample. The percentages of fiber used were varied as 0.0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 1.2% (by dry weight of samples). The soil specimens were compacted under the conditions of maximum dry density and optimum water content. The surficial cracking area was measured to determine the crack intensity factor (CIF) of the soil samples. The desiccation crack test results indicated that the percentage of volume change of the compacted soil specimen decreased with addition of fiber. The change in the soil surface area decreased with increasing in the fiber content (FC), and consequently, the volumetric shrinkage strain decreased. The CIF for the soil without fiber (FC?=?0.0%) were significantly higher than the soil with fiber additive. The CIF of soil at FC?=?0.0% decreased from 2.75% to 0.6% for the soil at FC?=?0.2%. It was also found that the maximum crack depth reaches almost 50% of the thickness of the soil without fiber additive. This study suggests the potential application of the fiber additives to soils as an available method to suppress desiccation cracks encountered in landfill cover barriers.     

Environmental controls on photosynthetic production and ecosystem respiration in semi-arid grasslands of Mongolia

The Mongolian steppe zone comprises a major part of East Asian grasslands. The objective of this study was to separately evaluate the quantitative dependencies of gross primary production (GPP) and ecosystem respiration (R_eco) on the environmental variables of temperature, moisture, radiation, and plant biomass in a semi-arid grassland ecosystem. We determined GPP and R_eco using transparent and opaque closed chambers in a grassland dominated by Poaceae species in central Mongolia during five periods: July 2004, May 2005, July 2005, September 2005, and June 2006. Values of GPP were linearly related to live aboveground biomass (AGB) enclosed by the chamber. The amount of GPP per unit ground area differed among the study periods, whereas GPP normalized by the amount of AGB did not differ significantly among the periods, suggesting that plant production per unit green biomass did not depend on the phenological stage. GPP/AGB fit well a rectangular hyperbolic light–response curve for all the study periods. When the air and soil were dry, considerable reduction in GPP was observed. The GPP/AGB ratio was also expressed as individual functions of air temperature, vapor pressure deficit, and volumetric soil water content. R_eco was exponentially related to the soil temperature and the relationship was modified by soil moisture. The amount of R_eco and its temperature sensitivity (Q₁₀) declined with decreasing soil moisture. Sharp increases of R_eco after rainfall events were observed. The values of R_eco, even including the rain-induced pulses, were expressed well as a bivariate function of soil temperature and soil moisture near the soil surface.     

Retrospective diagnosis of feline GM2 gangliosidosis variant 0 (Sandhoff-like disease) in Japan: possible spread of the mutant allele in the Japanese domestic cat population

GM2 gangliosidosis variant 0 (human Sandhoff disease) is a lysosomal storage disease caused by simultaneous deficiencies of acid beta-hexosaminidase (Hex) A and Hex B due to an abnormality of beta-subunit, a common component in these enzyme molecules, which is coded by the HEXB gene. In the present study, a retrospective diagnosis was performed in 2 previous suspected cases of feline Sandhoff-like disease using a DNA test to detect the causative mutation identified previously in 4 cats in 2 other families of Japanese domestic cats. Enzymic analysis was also performed using stored leukocytes and plasma collected from the subject families in order to investigate the usefulness of enzymic diagnosis and genotyping of carriers. The DNA test suggested that the 2 cases were homozygous recessive for the mutation. Consequently, 6 cats homozygous for the same mutation have been found in 4 separate locations of Japan, suggesting that this mutant allele may be spread widely in the Japanese domestic cat populations. In enzymic analysis, Hex A and Hex B activities in leukocytes and plasma measured using 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide as a substrate were negligible in affected cats, compared with those in normal and carrier cats. However, there was a wide overlap in enzyme activity between normal and carrier cats. Therefore, it was concluded that enzymic analysis is useful for diagnosis of affected cats, but is not acceptable for genotyping of carriers.     

Intranasal hemangiosarcoma in a dog

Magnetic resonance (MR) was conducted for an 8-year-old, intact male Spitz with sneezing, serous discharge and epistaxis from the left nasal cavity. MR imaging showed a nasal cavity-occupied mass of iso-intensity on T1WI , high-intensity on T2WI and markedly enhanced on contrast-enhanced T1WI at parts of rostal to medial ocular angle in the left cavity. After Surgery and intraoperative radiation, the mass was diagnosed intranasal hemangiosarcoma by histopathology. Although the dog showed the finding, which suggested recurrence after the treatment ending, about 30 months later, it maintained good conditions without evidence of metastasis.     

Generation of monoclonal antibody against canine neural-cell adhesion molecule

A monoclonal antibody, K9BYU, was generated using Escherichia coli recombinant extracellular domain of canine neural-cell adhesion molecule (N-CAM) as an antigen. Immunoreactivity of K9BYU to insect cell recombinant canine N-CAM was demonstrated by Western blotting using Sf9 insect cells transfected with the canine N-CAM gene. In Western blotting against canine brain tissue, K9BYU detected three isoforms of N-CAM that correspond to three major isoforms of human and mouse N-CAM (N-CAM-120, -140, and -180). From these results, K9BYU was considered to be a useful tool for research of canine N-CAM.     

Expression of alpha-hemoglobin stabilizing protein and cellular prion protein in a subclone of murine erythroleukemia cell line MEL

Alpha-Hemoglobin stabilizing protein (AHSP) functions as the erythroid-specific molecular chaperon for alpha-globin. AHSP gene expression has been reported to be downregulated in hematopoietic tissues of animals suffering from prion diseases though the mechanism remains to be clarified. Herein, we demonstrate that MELhipod8 cells, a subclone of murine erythroleukemia (MEL) cells, have prion protein (PrPc) on the cell surface and have highly inducible expression of the AHSP and alpha- and beta-globin genes, resembling the expression pattern of the PrP and AHSP genes in bipotential erythroid- and megakaryocyte-lineage cells followed by erythroid differentiation in normal erythropoiesis. Moreover, MELhipod8 cells exhibit greater effective erythroid differentiation with a population of hemoglobinized normoblast-like cells than that observed for the parental MEL cells. These findings suggest that MELhipod8 cells could provide a mechanism for downregulation of the AHSP gene in prion diseases.