Effects of high ambient temperature on urea‐nitrogen recycling in lactating dairy cows

Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature‐controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross‐over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [¹⁵N₂]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea‐N excretion was increased. The ratio of urea‐N production to digestible N was increased, whereas the proportion of gut urea‐N entry to urea‐N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea‐N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea‐N production and reduction of gut urea‐N entry, in relative terms, were associated with increased urinary urea‐N excretion of lactating dairy cows in higher thermal environments.     

Development of avian embryo manipulation techniques and their application to germ cell manipulation

The development of chicken embryo culture techniques, from single‐cell stage to hatching, makes it possible to manipulate developing embryos at any developmental stage. Production of germline chimeric chickens by the transfer of stage X blastodermal cells or primordial germ cells enables the manipulation of germline cells in vitro. Production of transgenic chickens has been attempted by the retroviral vector method, microinjection of DNA into a fertilized ovum at the single‐cell stage, use of chimeric intermediates produced by the transfer of stage X blastodermal cells or primordial germ cells, manipulation of spermatozoa, and in vivo manipulation of gonads. So far, the only non‐viral method that has successfully produced transgenic chickens is microinjection of DNA into a fertilized ovum. Manipulation of primordial germ cells could become an efficient system for producing transgenic chickens by combining it with the highly efficient transfection method or the in vitro culture system for primordial germ cells. Preservation of avian genetic resources has now become possible by cryopreservation of stage X blastodermal cells or primordial germ cells as well as spermatozoa. The development of nuclear transfer techniques for avian species is necessary.     

Utility of 5-aminolaevulinic acid fluorescence-guided endoscopic biopsy for malignant mesothelioma in a cat and dog

Malignant mesothelioma (MM) is uncommon in cats and dogs and can be challenging to diagnose. Adequate tissue sampling is required for superior diagnostic accuracy. Protoporphyrin IX, a metabolite of 5-aminolaevulinic acid (5-ALA), is a photosensitiser for photodynamic diagnosis (PDD). To the best of our knowledge, no study has reported the use of 5-ALA-PDD to detect MM in veterinary medicine. The present study describes the use of 5-ALA-PDD for MM diagnosis in a cat and dog, as well as the effectiveness of intracavitary chemotherapy. We evaluated the use of PDD with 5-ALA hydrochloride (5-ALA-PDD) in two cases of MM. A 12-year-old cat presented with a 1-month history of respiratory distress, and a 9-year-old dog presented with a 3-month history of mild abdominal distention. We endoscopically biopsied lesions in both the cases using 5-ALA-PDD. Histopathological examination revealed mesothelioma, and immunohistochemical staining was positive for calretinin. Both patients were treated with carboplatin. The cat died of respiratory failure. Although, the dog's condition improved 21 days after the first chemotherapeutic drug administration, the dog died on day 684 owing to cardiac-related issues. 5-ALA-PDD is thus, safe and feasible for the diagnosis of MM in veterinary medicine.     

Allele‐specific polymerase chain reaction typing and sequencing of mitochondrial D‐loop region in broiler chickens in Japan

This study aimed to comprehend a feature of single nucleotide polymorphism (SNP) in mitochondrial DNA (mtDNA) mainly of general broiler chickens in Japan. We typed two SNP sites (199C/T and 792A/G) of the D‐loop region in mtDNA by allele‐specific PCR (AS‐PCR) in 359 broiler (182 chunky and 177 cobb) and 506 layer (233 White Leghorn, 140 Barred Plymouth Rock and 133 Rhode Island Red) chickens. The SNP of 199C or 792A by AS‐PCR was observed in the chunky and cobb chickens, and not in the layers. The haplotype 199T/792G was observed in a part of cobb and all layers. By the result of AS‐PCR haplotyping and the broiler brands, the D‐loop region was sequenced in 44 broiler chickens (20 chunky and 24 cobb) and compared with the layers’ sequence data. Among the broiler and layer chickens, 21 SNP sites (including one insertion) and 11 sequence haplotypes were observed. Haplotype variation or correspondence was observed in and between the broiler brands. This study provides important information to establish a chicken meat traceability system by SNP haplotyping of mtDNA in Japan.     

Irradiation history of Itokawa regolith material deduced from noble gases in the Hayabusa samples

Noble gas isotopes were measured in three rocky grains from asteroid Itokawa to elucidate a history of irradiation from cosmic rays and solar wind on its surface. Large amounts of solar helium (He), neon (Ne), and argon (Ar) trapped in various depths in the grains were observed, which can be explained by multiple implantations of solar wind particles into the grains, combined with preferential He loss caused by frictional wear of space-weathered rims on the grains. Short residence time of less than 8 million years was implied for the grains by an estimate on cosmic-ray-produced (21)Ne. Our results suggest that Itokawa is continuously losing its surface materials into space at a rate of tens of centimeters per million years. The lifetime of Itokawa should be much shorter than the age of our solar system.     

Mineral characteristics of the leaves of 166 plant species with different phylogeny in the temperate region

The P-N regression coefficient was moderate in Magnoliales,Coniferopsidae, Pteridophyta, and Asterids, but very high in Caryophyllids,and very low in Rosids. The K-N regression coefficient in trees remainedconstant regardless of evolution, and that in grasses was high except forRosids compared with that in trees. The coefficient was very high inCaryophyllids and was very low in Rosids. The N-Ca and N-Mg relationshipwas not estimated at all, suggesting that the mechanism of Ca and Mgaccumulation was completely different from that of N related accumulation.The Zn and Cu concentrations were related to the N concentration.The Al concentration in leaves was negatively correlated with the N, P, K,Ca, Mg, Na, Cu, Zn, Mn, and Fe concentrations, while the N, P, K, andMn concentrations in leaves increased slightly with the increase of Alconcentration in the high Al concentration. The Na concentration in leavesrelated negatively to the P, Ca, Cu, Zn, Mn and Al concentration range.Thus, it was demonstrated that most of the minerals in leaves accumulatenegatively Al and Na indicating that there are antagonistic mechanisms formineral accumulation in leaves among Al or Na and other mineralelements.     

N-Acetyl-d-Glucosamine-Binding Lectin in Acropora tenuis Attracts Specific Symbiodiniaceae Cell Culture Strains

Many corals establish symbiosis with Symbiodiniaceae cells from surrounding environments, but very few Symbiodiniaceae cells exist in the water column. Given that the N-acetyl-d-glucosamine-binding lectin ActL attracts Symbiodiniaceae cells, we hypothesized that corals must attract Symbiodiniaceae cells using ActL to acquire them. Anti-ActL antibody inhibited acquisition of Symbiodiniaceae cells, and rearing seawater for juvenile Acropora tenuis contained ActL, suggesting that juvenile A. tenuis discharge ActL to attract these cells. Among eight Symbiodiniaceae cultured strains, ActL attracted NBRC102920 (Symbiodinium tridacnidorum) most strongly followed by CS-161 (Symbiodinium tridacnidorum), CCMP2556 (Durusdinium trenchii), and CCMP1633 (Breviolum sp.); however, it did not attract GTP-A6-Sy (Symbiodinium natans), CCMP421 (Effrenium voratum), FKM0207 (Fugacium sp.), and CS-156 (Fugacium sp.). Juvenile polyps of A. tenuis acquired limited Symbiodiniaceae cell strains, and the number of acquired Symbiodiniaceae cells in a polyp also differed from each other. The number of Symbiodiniaceae cells acquired by juvenile polyps of A. tenuis was correlated with the ActL chemotactic activity. Thus, ActL could be used to attract select Symbiodiniaceae cells and help Symbiodiniaceae cell acquisition in juvenile polyps of A. tenuis, facilitating establishment of symbiosis between A. tenuis and Symbiodiniaceae cells.     

Effects of oral glucosamine hydrochloride administration on plasma free amino acid concentrations in dogs

We examined the effects of oral glucosamine hydrochloride (GlcN), N-acetyl-D-glucosamine (GlcNAc) and d-glucose (Glc) administration on plasma total free amino acid (PFAA) concentrations in dogs. The PFAA concentrations increased in the control group and the GlcNAc group at one hour after feeding, and each amino acid concentration increased. On the other hand, in the GlcN group and the Glc group PFAA concentrations decreased at one hour after feeding. A significant decrease in amino acid concentration was observed for glutamate, glycine and alanine. Our results suggest the existence of differences in PFAA dynamics after oral administration of GlcN and GlcNAc in dogs.     

Purification and characterization of phytase induced in tomato roots under phosphorus-deficient conditions

Phytase (myo-inositol hexakisphosphate phosphohydrolase; EC 3.1.3.8) was purified from roots of tomato plants grown under phosphorus-deficient conditions using five purification schemes. The phytase was successfully separated from the major acid phosphatase to an electrophoretic homogeneity. The native molecular weight of this enzyme was estimated to be about 164 kD by Bio-Gel P-200 gel filtration. The molecular weight of the subunit on SDS-PAGE was approximately 82 kD, indicating that the native form of the enzyme was a homodimer. The isoelectric point of tomato phytase was about 5.5. The enzyme exhibited a high affinity for phytic acid (K _m = 38 μM), and was strongly inhibited by phosphate, molybdate and fluoride. Among other characteristics of tomato phytase, the pH and temperature optima were 4.3 and 45°C, respectively. Tomato phytase contained a fairly high concentration of aspartic, glutamic acid and glycine residues.     

Isolation and characterization of a cDNA from Catharanthus roseus which is highly homologous with phosphate transporter

The PIT1 gene which is highly homologous with phosphate transporter was isolated from Catharanthus roseus and analyzed. The cBNA PIT1 contained an open reading frame of 542 amino acids and its sequence showed a 31, 30, and 34% identity with the phosphate transporter of Saccharomyces cerevisiae (PBO84), Neurospora crassa (PHO-5), and Glomus versiforme (GvPT), respectively. Furthermore, the cDNA PIT1 encoded a highly hydrophobic protein with 12 putative membrane-spanning regions and contained a conserved amino acid sequence reported in the human glucose transporter super-family* S. cerevisiae strain DpU (pho84 knockout strain) was unable to grow on low phosphate (55 μM) medium (LP medium). Expression of the PIT1 cDNA enabled DpU to grow on LP medium. Northern hybridization analysis revealed that the PIT1 gene was expressed in roots, stems, and young whole plant of C. roseus, but not in leaves.