Myofibrillar proteolysis in chick muscle cell cultures during heat stress

The effect of heat stress on protein oxidation and myofibrillar proteolysis in chick myotubes was investigated. Myotubes were incubated at 37 or 41°C for 6 and 24 h. Protein carbonyl content, as an index of protein oxidation, increased more at 41°C than at 37°C for 6 and 24 h incubations. N^τ‐methylhistidine release as an index of myofibrillar proteolysis also increased more at 41°C than at 37°C for 6 and 24 h incubations. Proteasome activity also increased more under those same conditions. Calpain and cathepsin D but not B + L activities showed a greater increase at 41°C than at 37°C for 24 but not the 6 h incubation. These results indicate that heat stress increases protein oxidation and proteasome activity, resulting in an increase in myofibrillar proteolysis for short‐term incubation and, for long‐term incubation, it increases calpain, proteasome and cathepsin D activities, finally accelerating myofibrillar proteolysis in chick myotubes.     

Changes in the predicted function of the rumen bacterial community of Japanese Black beef cattle during the fattening stages according to Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses

We investigated changes in the predicted functions of the rumen bacterial community in Japanese Black beef cattle during fattening. Nine cattle were fed a high-concentrate diet during the early, middle, and late fattening stages consecutively (10–14, 15–22, and 23–30 months of age, respectively). The rumen fluid and solid samples collected at each stage were subjected to sequencing analyses. The sequencing results were clustered and classified into operational taxonomic units (OTUs). Representative sequences and a raw counting table for each OTU were submitted to the Piphillin website. The predicted functions were revealed by the Kyoto Encyclopedia of Genes and Genomes database as the ratio of the total sequence. In the early stage, “Biosynthesis of secondary metabolites” was significantly higher in the fluid fraction than in the solid fraction. “Two-component system” in the middle stage was significantly lower and “Purine metabolism” in the late stage was significantly higher in the fluid fraction than those in the solid fraction. The fluid fraction was significantly correlated with acetic acid, propionic acid, and bacterial metabolism, such as “Biosynthesis of secondary metabolites” and “Sugar metabolism.” Moreover, the solid fraction was correlated with “Purine metabolism” and “Biosynthesis of secondary metabolism”. These results suggest that the rumen bacterial community in Japanese Black beef cattle adapts to changes in rumen conditions by altering their functions in response to a long-term high-grain diet.     

Estimation of genetic parameters for carcass grading traits,image analysis traits,and monounsaturated fatty acids in Japanese Black cattle from Hyogo Prefecture

Genetic parameters for carcass grading traits, image analysis traits, and monounsaturated fatty acid (MUFA) percentages were estimated in 29,942 Japanese Black cattle from Hyogo Prefecture. The analyzed traits included five carcass grading traits, two image analysis traits, fat area ratio and fineness index, and two MUFA traits, one measured in intermuscular fat using near-infrared spectroscopy (NIRS) and the other in intramuscular fat using gas chromatography (GC). The heritability estimates of image analysis traits and MUFA were moderate to high, ranging from 0.395 to 0.740, and it was considered that they could be improved simultaneously with carcass grading traits because no severe genetic antagonism was observed. Although the heritability of the NIRS-based intermuscular MUFA was slightly lower than that of the GC-based intramuscular MUFA, the genetic correlation between the two methods was as high as 0.804. These results indicate that the NIRS method can be used as an alternative evaluation procedure to predict MUFA in intramuscular fat in the longissimus muscle.     

Development and evaluation of an enzyme-linked immunosorbent assay based on recombinant TgSRS2 for serodiagnosis of Toxoplasma gondii infection in cats

An enzyme-linked immunosorbent assay (ELISA) based on recombinant SAG1-related sequence 2 of Toxoplasma gondii (rTgSRS2) was developed to detect toxoplasmosis in cats. The specificity and sensitivity of rTgSRS2 ELISA were confirmed using a series of serum samples from T. gondii-experimentally infected mice. A total of 76 field samples from cats were examined by the developed ELISA. The rTgSRS2 ELISA showed a good diagnostic performance characterized by high concordance (88.16) and kappa value (0.76) with latex agglutination test (LAT). The sensitivity and specificity of the test were 92.68% and 82.86%, respectively. These results suggest that the ELISA based on rTgSRS2 could be a useful tool for serodiagnosis of T. gondii infection in cats.     

Potent Natural Immunomodulator,Rice Water‐Soluble Polysaccharide Fractions with Anticomplementary Activity

Water‐soluble polysaccharide fractions, fractionated with ammonium sulfate from the hot‐water‐extract of rice bran and endosperm, showed a potent anticomplementary activity. As compared with water‐soluble polysaccharide isolated from Angelica acutiloba, which is a well‐known medicinal herb, the rice fractions showed similar or higher potency. Protease digestion, periodate oxidation, and hydroxylamine treatments indicated that anticomplementary activity is due to polysaccharide moiety rather than protein moiety and the polyphenol moieties, ferulic acid, being an integral component in rice bran proteoglycan. These results suggest that a water‐soluble proteoglycan and a polysaccharide in rice modulate complement activity. This is a new example of natural biological response modifiers in food.     

Amino acid substitution at position 95 in rabies virus matrix protein affects viral pathogenicity

We previously reported that rabies virus strain CE(NiM), but not the parental Ni-CE strain, killed mice after intracerebral inoculation. CE(NiM) and Ni-CE are genetically identical except for two amino acids at positions 29 and 95 in the M protein. In this study, to identify which residue determines the pathogenicity, we examined pathogenicities of two Ni-CE mutants, CE(NiM29) and CE(NiM95), which were established by replacement of an amino acid residue at position 29 or 95 in the Ni-CE M protein with the corresponding residue of CE(NiM), respectively. We found that CE(NiM95), but not CE(NiM29), killed mice, indicating that the amino acid at position 95 in the M protein is the pathogenic determinant.