Relationship between blood calcium level and ST peak interval of electrocardiographic variables in peripartum Holstein cows

The association between blood calcium levels and electrocardiographic variables was compared in 137 normal parturient and 36 peripartum recumbent Holstein cows to determine whether hypocalcemia in peripartum dairy cows can be rapidly diagnosed using electrocardiograph. Inverse of STc (ST peak interval/SS interval^0.5) and blood ionized calcium or serum calcium concentrations were strongly correlated, and both correlation coefficients were 0.81 (P<0.001). The 95% prediction interval indicated that cows with STc >0.385 ± 0.001 sec are very likely to be hypocalcemic (blood ionized or serum calcium concentrations of <0.9 mmol/l or <7.5 mg/dl, respectively). These findings indicate that hypocalcemia in parturient cows can be non-invasively estimated using the STc.     

Cellularity of developing subcutaneous adipose tissue in Landrace and Meishan pigs: Adipocyte size differences between two breeds

Experiments were designed to compare the adipocyte cellularity of subcutaneous adipose tissue between growing Landrace (low backfat) and Meishan (high backfat) pigs at 1 week, 3 weeks, 6 weeks, 3 months and 5 months of age. As pigs aged, body weight and backfat thickness of both breeds significantly increased. When compared at equal ages, backfat thickness adjusted to equal body weight was greater for Meishan pigs. The mean diameter of fat cell size also increased with age, and by 6 weeks adipocytes from both outer and inner layers of subcutaneous adipose tissue were larger in Meishan pigs. At 5 months, approximately 80% of the adipose tissue mass in Meishan pigs was attributable to adipocytes measuring 95–165 µm in diameter, whereas adipocytes of 75–145 µm comprised most of the tissue mass in the Landrace. Although the contribution of smaller adipocytes (25–45 µm) to the tissue volume was negligible, both breeds showed a biphasic diameter distribution at all ages, suggesting that adipocyte hyperplasia is still active. Our results demonstrate that cellularity differences exist between the subcutaneous adipose tissues of Landrace and Meishan pigs, and adipocyte hypertrophy is the most overwhelming contributor to the greater backfat deposition for Meishan pigs.     

Effects of muscle type on beef taste‐traits assessed by an electric sensing system

To assess the role of muscle fiber type in beef taste‐traits, we analyzed cooked meats from bovine masseter, diaphragm, psoas major, longissimus thoracis, and semitendinosus muscles with an electric taste sensing system (INSENT SA402B). The system is composed of five taste sensors of polymer membranes fixing different lipids. The sensors, CT0, CA0, AAE, C00 and AE1 are designed to respond to the individual tastes of salty, sour, umami, bitter and astringent, respectively. The system found significant differences in the converted outputs of CA0 (cvCA0), C00 (cvC00) and AE1 (cvAE1) among the bovine muscles. The slow‐type muscles (masseter and diaphragm) showed lower cvCA0, higher cvC00, and higher cvAE1 than did the fast‐type muscles (psoas major, longissimus thoracis, and semitendinosus). Lactic acid content was different among muscle types and was highly related to the cvCA0 output and pH. carbonyl compounds and free fatty acids were higher in the slow‐type muscles. Free fatty acids were major components causing the difference in the C00 output among the muscle types. Iron content was also different among the muscle types and related to the cvC00 and cvAE1 outputs. These results suggested that the muscle fiber type affects the beef taste characteristics.     

Multiplex PCR assay for simultaneous detection of MBI-D and Q<Subscript>o</Subscript>I resistance in rice blast fungus

For sustainable control of rice blast with fungicides, efficient monitoring of the emergence and spread of fungicide-resistant isolates is needed. We developed simple and reliable PCR-based DNA markers to detect isolates resistant to melanin biosynthesis inhibitor targeting scytalone dehydratase (MBI-D) and quinone outside inhibitor (Q_oI) fungicides. Through the use of DNA templates prepared from mycelia on filter paper or from infected leaves, these markers enable rapid (a few hours) genotyping of point mutations that confer resistance. The developed multiplex marker detected resistance to both MBI-D and Q_oI in a single PCR and further reduced the time needed for diagnosis.     

Sequential expression of myogenic regulatory factors in bovine skeletal muscle and the satellite cell culture

Myogenic regulatory factors (MRFs) are important in the control of skeletal muscle development. To understand myogenic regulation by MRFs in bovine adult muscle cells, their expressions, namely that of Myf5, MyoD, myogenin, and MRF4 in the biceps femoris muscle (BF) and in the satellite cell culture, were analyzed by RT-PCR. In the BF, all four MRFs were expressed and in particular, myogenin and MRF4 were strongly expressed, whereas Myf5 was faintly expressed. The satellite cells prepared from the BF expressed Myf5, but only a trace of MyoD, at day 9 of culture. During the growth of the cells to day 14, the MyoD and myogenin expressions gradually increased, and that of MyoD expression reached its maximum at the confluence of the culture. After induction of myogenic differentiation by a serum-free medium at day 14, Myf5 expression gradually decreased, and the up-regulated expression of MyoD was suppressed, whereas myogenin expression continued to increase sharply. Following the myogenin expression, MRF4 also drastically increased toward the myotube formation of the cells. When huge myotubes were formed at day 18, Myf5 was expressed at a low level, whereas the MyoD expression remained at a moderate level.     

Comparative sequence analysis of four myosin heavy chain isoforms expressed in porcine skeletal muscles: Sequencing and characterization of the porcine myosin heavy chain slow isoform

A nucleotide sequence including the full coding region for the myosin heavy chain (MyHC) slow isoform was determined from the longissimus skeletal muscle. The deduced amino acid sequence was 1935 residues, which was the same length as the human and rat MyHC-slow isoforms. The porcine MyHC-slow isoform showed 97.6% and 97.4% amino acid identities to the human and rat isoforms on their entire regions, respectively. The functional regions were also highly conserved among mammalian MyHC-slow isoforms. Amino acid substitutions between the porcine MyHC-slow and MyHC-fast isoforms were concentrated on the functional regions. Loop 1, the controlling region of nucleotide binding and release, was conserved among the fast isoforms, but not between the slow and fast isoforms. Loop 2, a part of the actin binding region, was not conserved among any of the isoform types, and the most substitutions in this region were found in the slow isoform. The myosin essential light chain binding region was conserved among the fast isoforms, except for some substitutions in the 2b isoform, but was clearly different in the slow isoform. The myosin regulatory light chain binding region was conserved among the fast isoforms, but not between the slow and fast isoforms. These results indicate that the functional difference between the porcine MyHC-slow and -fast isoforms are controlled by the sequence diversity at the four functional regions compared.     

Increase in soil carbon sequestration using rice husk charcoal without stimulating CH4 and N2O emissions in an Andosol paddy field in Japan

Abstract

Biochar application has been recognized as an effective option for promoting carbon (C) sequestration, but it may also affect the production and consumption of methane (CH₄) and nitrous oxide (N₂O) in soil. A 1-year field experiment was conducted to investigate the effects of rice husk charcoal application on rice (Oryza sativa L.) productivity and the balance of greenhouse gas exchanges in an Andosol paddy field. The experiment compared the treatments of rice husk charcoal applied at 10, 20 and 40 Mg ha^?1 (RC10, RC20 and RC40, respectively), rice husk applied at 20 Mg ha^?1 (RH20), and the control (CONT). Rice straw and grain yields did not significantly differ among the treatments. The seasonal cumulative CH₄ emissions were 38–47% higher from RC10, RC20 and RC40 than from the CONT. However, the increases were not in proportion to the application rates of rice husk charcoal, and their values did not significantly differ from the CONT. On the contrary, the RH20 treatment significantly increased the cumulative CH₄ emission by 227% compared to the CONT. The N₂O emissions during the measurement were not affected by the treatments. As a result, the combined global warming potential (GWP) of CH₄ and N₂O emissions was significantly higher in RH20 than in the other treatments. There was a positive linear correlation between C storage in the top 10 cm of soil and the application rate of rice husk charcoal. The increases in soil C contents compared to the CONT corresponded to 98–149% of the C amounts added as rice husk charcoal and 41% of the C added as rice husk. Carbon dioxide (CO₂) fluxes in the off season were not significantly different among RC10, RC20, RC40 and CONT, indicating that C added as rice husk charcoal remained in the soil during the fallow period. The CO₂ equivalent balance between soil C sequestration and the combined GWP indicates that the rice husk charcoal treatments stored more C in soil than the CONT, whereas the RH20 emitted more C than the CONT. These results suggest that rice husk charcoal application will contribute to mitigating global warming without sacrificing rice yields.