Relationships between ammonia oxidizers and N2O and CH4 fluxes in agricultural fields with different soil types

Nitrous oxide (N₂O) is a greenhouse gas that contributes to the destruction of stratospheric ozone, and agricultural soil is an important source of N₂O. Aerobic soils are sinks for atmospheric methane (CH₄), a greenhouse gas. Ammonia monooxygenase (AMO) can oxidize CH₄, but CH₄ is mostly oxidized by methane monooxygenase (MMO), and CH₄ oxidation by AMO is generally negligible in the soil. We monitored the N₂O and CH₄ fluxes after urea application in fields containing different soils using an automated sampling system to determine the effects of environmental and microbial factors on the N₂O and CH₄ fluxes. The soil types were Low-humic Andosol (Gleyic Haplic Andosol), yellow soil (Gleyic Haplic Alisol) and gray lowland soil (Entric Fluvisol). Cumulative N₂O emissions from the yellow soil were higher than those from other soil types, although the difference was not significant. The CH₄ uptake level by Andosol was one order of magnitude higher than that by other soils. There were significant relationships between the ammonia oxidation potential, AOB and AOA amoA copy numbers, and the CH₄ uptake. In contrast, the gene copy numbers of methane-oxidizing bacteria (MOB) pmoA were below the detection limit. Our results suggested that the AMOs of AOB and AOA may have more important roles than those previously considered during CH₄ oxidation in agricultural soils treated with N fertilizers.     

Production of bioactive bovine fibroblast growth factor 4 in E. coli based on the common nucleotide sequence of its structural gene in three breeds

Fibroblast growth factor 4 (FGF4) is considered a crucial gene in the proper development of bovine embryos. We recently determined the FGF4 gene sequence in eight cattle derived from three breeds and revealed a common nucleotide sequence of the structural gene encoding FGF4, which leads to the deletion and mutation of amino acid sequences in the mature FGF4 (Pro³²‐Leu²⁰⁶) compared with the sequence previously reported. In the present study, HisbFGF4, a 6× histidine‐tagged bovine FGF4 (Pro³²‐Leu²⁰⁶), was produced in Escherichia coli based on the validated nucleotide sequence and purified by heparin column chromatography. In primary bovine fibroblasts, HisbFGF4 showed significant mitogenic activity, whereas, intriguingly, the activity of a commercially available recombinant human FGF4 (Gly²⁵‐Leu²⁰⁶) produced in E. coli was weaker than that of HisbFGF4. In conclusion, the present study provides a simple method for the production of a bioactive bovine FGF4 derivative in E. coli utilizing its structural gene elucidated by us.     

Effect of modified ultrafiltration on cytokines and hemoconcentration in dogs undergoing cardiopulmonary bypass

Cardiac surgery using cardiopulmonary bypass (CPB) generates severe inflammatory reactions secondary to hemodilution and surgical stress. This study was conducted to evaluate whether modified ultrafiltration (MUF) could be performed safely and to clarify its effects during mitral valve repair in dogs in terms of hemodilution and the status of inflammatory cytokines. We retrospectively studied 38 dogs with mitral valve disease who underwent MUF immediately after mitral valve repair under CPB. To determine the effect of MUF, we measured the pre- and post-MUF blood dilution and blood cytokine levels. The levels of red blood cells, hematocrit (HCT), and albumin were significantly increased after MUF, whereas interleukin (IL)-6 levels were significantly increased from 24.3 (range 9.6–54.6) to 32.3 (15.9–65.1) pg/ml. The levels of IL-8 and IL-10 declined significantly after MUF, from 368.2 (246.1–669.4) and 45.4 (28.6–76.1) to 272.2 (174.1–414.4) and 28.8 (18.8–44.5) pg/ml, respectively. Our results demonstrated that MUF can be applied in dogs undergoing CPB and is effective in achieving hemoconcentration. Moreover, MUF may be useful for the removal of cytokines. Further studies are needed to validate these findings and clarify the effects of inflammatory cytokines after CPB.     

Production of Middle White Piglets after Transfer of Embryos Produced In Vitro

The present study was conducted to examine the feasibility of in vitro embryo production and transfer technologies for producing Middle White piglets. After collection from three retired Middle White sows, a total of 222 oocytes were matured, fertilized and cultured in vitro, and a total of 50 embryos from the 4-cell to blastocyst stage were produced by the 4th or 5th day. These embryos were transferred individually into three recipients along with 5 in vivo-derived Duroc blastocysts. All of the recipients became pregnant, and they farrowed a total of 9 Middle White and 9 Duroc piglets. These results suggest that in vitro embryo production using ovaries from retired sows is useful for reproduction of pigs of pure breeds including the Middle White for breeding activities and conservation/utilization of genetic resources.     

Expression and regulation of Foxa2 in the rat uterus during early pregnancy

The forkhead box a (Foxa) protein family has been found to play important roles in mammals. Recently, the expression of Foxa2 was reported in the mouse uterus, and it was reported to be involved in regulation of implantation. However, the regulation of Foxa2 expression in the uterus is still poorly understood. Therefore, the present study was conducted to investigate the expressional profiles of Foxa2 in the rat uterus during the estrus cycle and pregnancy. Furthermore, the effect of steroid hormones and Hedgehog protein on the expression of Foxa2 was analyzed in vivo and in vitro. In this study, the level of expression of Foxa2 was low in the rat uterus during the different stages of the estrus cycle. However, the expression increased transiently during early pregnancy at 3.5 days post coitus (dpc) and decreased at 5.5 dpc. In ovariectomized rats, P4 treatment had no effect on the expression of Foxa2 compared with the expression in control animals. Moreover, the expression of Foxa2 in cultured epithelial cells was not increased by P4 treatment in vitro. However, Foxa2 expression was significantly decreased in the rat uterus after 24 h of E2 treatment. Treatment of cells with a recombinant Hedgehog protein significantly increased the expression of Foxa2. These results suggest that the expression of Foxa2 may transiently increase just before the implantation and it may be regulated by E2 and Hedgehog protein.     

Antibacterial abilities of intestinal bacteria from larval and juvenile Japanese flounder against fish pathogens

The present study was undertaken to examine the antibacterial abilities of intestinal bacteria isolated from juveniles and larvae of Japanese flounder Paralichthys olivaceus . Newly hatched larvae of flounder were held in a 100 L plastic circular tank and fed rotifiers, Artemia nauplii and commercial feeds, depending on the developmental stage of the fish. Genera Aeromonas , Moraxella and Vibrio were predominantly isolated from the intestinal tracts of Japanese flounder at larval and juvenile stages, whereas Aeromonas , Bacillus , coryneforms, Moraxella , Pseudomonas and Vibrio were detected at high densities in live diets and artificial feeds. Antibacterial bacteria accounted for 1.7–24.3% of the intestinal isolates against Lactococcus garvieae , Pasteurella piscicida , Vibrio anguillarum and V. vulnificus . In particular, as much as 53.3% of Vibrio spp. other than Vibrio -swarmer isolated from 197-day-old juveniles inhibited the growth of P. piscicida . These results suggest that intestinal bacteria having antibacterial activity play a role in the prevention of infectious diseases.