Effects of bamboo biochar application on global warming in paddy fields in Ehime prefecture,Southern Japan

Biochar application can reduce global warming via carbon (C) sequestration in soils. However, there are few studies investigating its effects on greenhouse gases in rice (Oryza sativa L.) paddy fields throughout the year. In this study, a year-round field experiment was performed in rice paddy fields to investigate the effects of biochar application on methane (CH₄) and nitrous oxide (N₂O) emissions and C budget. The study was conducted on three rice paddy fields in Ehime prefecture, Japan, for 2 years. Control (Co) and biochar (B) treatments, in which 2-cm size bamboo biochar (2 Mg ha^?1) was applied, were set up in the first year. CH₄ and N₂O emissions and heterotrophic respiration (Rh) were measured using a closed-chamber method. In the fallow season, the mean N₂O emission during the experimental period was significantly lower in B (67 g N ha^?1) than Co (147 g N ha^?1). However, the mean CH₄ emission was slightly higher in B (2.3 kg C ha^?1) than Co (1.2 kg C ha^?1) in fallow season. The water-filled pore space increased more during the fallow season in B than Co. In B, soil was reduced more than in Co due to increasing soil moisture, which decreased N₂O and increased CH₄ emissions in the fallow season. In the rice-growing season, the mean N₂O emission tended to be lower in B (?104 g N ha^?1) than Co (?13 g N ha^?1), while mean CH₄ emission was similar between B (183 kg C ha^?1) and Co (173 kg C ha^?1). Due to the C release from applied biochar and soil organic C in the first year, Rh in B was higher than that in Co. The net greenhouse gas emission for 2 years considering biochar C, plant residue C, CH₄ and N₂O emissions, and Rh was lower in B (5.53 Mg CO₂eq ha^?1) than Co (11.1 Mg CO₂eq ha^?1). Biochar application worked for C accumulation, increasing plant residue C input, and mitigating N₂O emission by improving soil environmental conditions. This suggests that bamboo biochar application in paddy fields could aid in mitigating global warming.     

Molecular characterization of avian polyomavirus isolated from psittacine birds based on the whole genome sequence analysis

Seven avian polyomaviruses (APVs) were isolated from seven psittacine birds of four species. Their whole genome sequences were genetically analyzed. Comparing with the sequence of BFDV1 strain, nucleotide substitutions in the sequences of seven APV isolates were found at 63 loci and a high level of conservation of amino acid sequence in each viral protein (VP1, VP2, VP3, VP4, and t/T antigen) was predicted. An A-to-T nucleotide substitution was observed in non-control region of all seven APV sequences in comparison with BFDV1 strain. Two C-to-T nucleotide substitutions were also detected in non-coding regions of one isolate. A phylogenetic analysis of the whole genome sequences indicated that the sequences from the same species of bird were closely related. APV has been reported to have distinct tropism for cell cultures of various avian species. The present study indicated that a single amino acid substitution at position 221 in VP2 was essential for propagating in chicken embryonic fibroblast culture and this substitution was promoted by propagation on budgerigar embryonic fibroblast culture. For two isolates, three serial amino acids appeared to be deleted in VP4. However, this deletion had little effect on virus propagation.     

Pathogenicity and immunogenicity of equine herpesvirus type 1 mutants defective in either gI or gE gene in murine and hamster models

To develop a live vaccine for equine herpesvirus type 1 (EHV-1), two EHV-1 mutants containing no heterogeneous DNA, DeltagI and DeltagE, were constructed with deletions in the open reading frame of either glycoprotein I (gI) or E (gE), respectively. In equine cell culture, deletion mutants formed smaller plaques than the parental and revertant viruses, but the one-step growth patterns of the deletion mutants and the parental strain were approximately the same. These results suggest that both gI and gE contribute to the ability of EHV-1 to spread directly from cell-to-cell, but that these glycoproteins are not required for viral growth in vitro. Mice and hamsters inoculated intranasally with these mutants showed no clinical signs, and continued to gain weight, whereas those inoculated with the parental virus exhibited a reduction in mean body weight. Furthermore, nervous manifestations were observed in hamsters inoculated with the parental virus. These results suggest that gI and gE have an important role in EHV-1 virulence including neurovirulence in experimental animal models. On the other hand, serum neutralizing antibodies were detected in mice immunized with DeltagI or DeltagE at two weeks after inoculation. Following challenge with the parental virus, DeltagI- or DeltagE-immunized mice were able to clear parental virus from their lungs faster than mock-immunized mice. These results suggest that the EHV-1 mutants defective in gI and in gE are attenuated but have ability to elicit immune responses in inoculated mice that contribute to virus clearance.     

Molecular genetic and pathogenic characterization of psittacid herpesvirus type 1 isolated from a captive galah (Eolophus roseicapillus) in Japan

Psittacid herpesvirus type 1 (PsHV-1) was isolated from a captive galah (Eolophus roseicapillus) in Japan that was suspected of having Pacheco's disease (PD), an acute fatal disease in psittacine birds. PsHV-1 has been classified into four genotypes based on the UL16 gene sequence. In the present study, we investigated the genetic and pathogenic characteristics of the isolated virus, FOY-1, compared with a reference strain, RSL-1. The FOY-1 strain was classified into PsHV-1 genotype 2. The FOY-1 strain was found to be less pathogenic to budgerigars than RSL-1, which was classified as genotype 4 in an in vivo study. This is the first report regarding the classification of originally isolated PsHV-1 in Japan and its characterization by animal infection experiment.     

Changes in rheological properties of grass carp fast skeletal myosin induced by seasonal acclimatization

To elucidate the effects of seasonal temperature acclimatization on thermal gelation of grass carp myosin, myosins from fish in different seasons were prepared and investigated for the changes in dynamic viscoelastic parameters including storage modulus (G′), loss modulus (G″) and damping factor (tan δ) upon heating. Myosins from fish in spring and summer had a temperature region of 38–44°C for the first marked increase of G′ higher than that of myosins from fish in autumn and winter (28–33°C). The measurement temperature-dependent changes in dynamic viscoelastic parameters such as G″ and tan δ were also different among the four myosins. While gel formation was observed with the spring and summer myosins, apparently in two steps, three steps were found in the autumn myosin. Furthermore, the winter myosin exhibited more than three steps for gel formation. These differences in rheological properties among the four myosins were considered to be attributed to the differences in thermodynamic and structural properties of these myosins previously reported.     

Using CF0218-ELISA to distinguish Chlamydophila felis-infected cats from vaccinated and uninfected domestic cats

Chlamydophila felis is a causative agent of acute and chronic conjunctivitis and pneumonia in cats. Cats can be vaccinated with killed or attenuated C. felis. However, current serodiagnostics cannot distinguish these cats from naturally infected cats. This causes difficulty of early diagnosis and seroepidemiological survey for C. felis. We previously reported that C. felis CF0218 can be used as a C. felis-infection-specific diagnostic antigen in experimentally infected and/or vaccinated cats. In this study, we evaluated an enzyme-linked immunosorbent assay using recombinant CF0218 as antigen (CF0218-ELISA) to detect anti-C. felis antibody in 714 sera of domestic cats whose histories of vaccination against C. felis are known. The 44 vaccinated cats were 93% negative using CF0218-ELISA; half of these scored positive by immunofluorescence assay (IFA) using C. felis-infected cells as antigen. The 670 non-vaccinated cats had CF0218-ELISA positivity rates that were statistically in agreement with IFA (18% vs. 21%). These results show that CF0218, which was identified as a C. felis-infection-specific antigen, is a useful serodiagnostic antigen to distinguish naturally C. felis-infected cats from vaccinated and non-infected cats.     

Effect of the number of tillages in fallow season and fertilizer type on greenhouse gas emission from a rice (Oryza sativa L.) paddy field in Ehime,southwestern Japan

Agricultural fields, including rice (Oryza sativa L.) paddy fields, constitute one of the major sources of atmospheric methane (CH₄) and nitrous oxide (N₂O). Organic matter application, such as straw and organic fertilizer, enhances CH₄ emission from paddy fields. In addition, rice straw management after harvest regulates CH₄ emissions in the growing season. The interaction of tillage times and organic fertilizer application on CH₄ and N₂O emissions is largely unknown. Therefore, we studied the effects of fallow-season tillage times and fertilizer types on CH₄ and N₂O emissions in paddy fields in Ehime, southwestern Japan. From November 2011 to October 2013, four treatments, two (autumn and spring) or one (spring) in the first year, or two (autumn and spring) or three (autumn, winter, and spring) in the second year times of tillage with chemical or organic fertilizer application, were established. Gas fluxes were measured by the closed-chamber method. Increasing the number of tillage times from one to two decreased succeeding CH₄ emission and the emission factor for CH₄ (EF_CH4) in the rice-growing season, suggesting that the substrate for CH₄ production was reduced by autumn and spring tillage in the fallow season. Higher EF_CH4 [1.8–2.0 kg carbon (C) ha^?1 d^?1] was observed when more straw was applied (6.9–7.2 Mg ha^?1) in the second year. Organic fertilizer application induced higher CH₄ emission just after the application as basal and supplemental fertilizers, especially at a lower straw application rate. This indicated that EF_CH4 in the organically managed fields should be determined individually. Organic fertilizer application with two tillage times induced N₂O efflux during the rice-growing season in the second year, but N₂O emissions were not affected by winter tillage. Although paddy fields can act as an N₂O sink because of reduced soil conditions when straw application was high, application of organic C and nitrogen as fertilizer can enhance N₂O production by the denitrification process during the growing season, especially in the ripening stage when soil anaerobic conditions became moderate. These results suggest that negative emission factors for N₂O (EF_N2O) can be applied, and EF_N2O of organic fertilizer should be considered during the estimation of N₂O emission in the paddy field.     

Sulfated cholecystokinin‐8 increases ghrelin secretion but does not affect oxyntomodulin in Holstein steers

The effect of appetite regulatory hormone cholecystokinin (CCK) on the secretions of oxyntomodulin (OXM) and ghrelin, and the effect of ghrelin on the secretions of CCK and OXM were studied in ruminants. Eight Holstein steers, 7 months old, 243 ± 7 kg body weight (BW), were arranged in an incomplete Latin square design (8 animals × 4 treatments × 4 days of sampling). Steers were intravenously injected with 10 µg of sulfated CCK‐8/kg BW, 20 µg of acyl ghrelin/kg BW, 100 µg of des‐acyl ghrelin/kg BW or vehicle. Blood samples were collected from ?60 min to 120 min relative to time of injection. Plasma concentrations of ghrelin, sulfated CCK and OXM were measured by double‐antibody radioimmunoassay. Plasma acyl ghrelin was increased to peak level (428.3 ± 6 pg/mL) at 60 min after injection of CCK compared with pre‐injected levels (203.3 ± 1 pg/mL). These results showed for the first time, that intravenous bolus injection of CCK increased ghrelin secretion in ruminants. In contrast, injection of ghrelin did not change CCK secretion. Administration of ghrelin or CCK has no effect on plasma OXM concentrations. In conclusion, our results show that administration of CCK increased ghrelin secretion but did not affect OXM release in ruminants. Ghrelin did not affect the secretions of CCK and OXM.     

Genetic and antigenic analysis of Chlamydia pecorum strains isolated from calves with diarrhea

Chlamydia pecorum (designated 22–58) was isolated in 2010 in HmLu-1 cells from the jejunum of a calf which died of necrotizing enterocolitis in Yamaguchi Prefecture, Japan. Immunohistochemical staining identified C. pecorum positive reactions in the jejunal villi. C. pecorum, designated 24–100, was isolated from the feces of a calf with diarrhea in another farm in Yamaguchi Prefecture in 2012. A significant increase in neutralizing antibody titers against C. pecorum was confirmed in paired sera. Nucleotide sequence identities of omp1 genes of the 2 isolates were 100%. The isolates were genetically and antigenically more closely related to C. pecorum Bo/Yokohama strain isolated from cattle with enteritis in Japan than to the other prototype strains, Bo/Maeda isolated from cattle with pneumonia and Ov/IPA isolated from sheep with polyarthritis. These results indicate that C. pecorum strains similar to 22–58 and 24–100 might be endemic in Yamaguchi Prefecture and cause enteric disease in cattle.