Distribution of recesses in the olfactory organ of African lungfish Protopterus aethiopicus

In the olfactory organ of lungfish, recesses at the bases of lamellae comprise sensory and nonsensory epithelia. The sensory epithelium of the recesses, the recess epithelium, is distinguished from the olfactory epithelium covering the lamella by the absence of ciliated olfactory receptor cells. Therefore, it has been suggested that the recess epithelium is a primordium of the vomeronasal organ of tetrapods. However, developmental changes in the number and distribution of recesses in the olfactory organ of lungfish were unknown. We examined four Protopterus aethiopicus specimens of body lengths 215–800 mm to determine the localization of recesses in their olfactory organs. Histological examination showed recesses at the bases of lamellae in all individuals examined. The recesses were localized mainly in the medial and caudal parts of the olfactory organs, especially in juveniles. Compared to smaller fish, larger fish had a larger number of recesses, distributed more broadly in their olfactory organs. Significance of the recess localization and its relationship to the function of lungfish olfactory organ warrants further investigation.     

Flowering Date1, a major photoperiod sensitivity gene in adzuki bean,is a soybean floral repressor E1 ortholog

Adzuki bean is an important legume crop originating in temperate regions, with photoperiod in sensitivity being a key factor in its latitudinal adaptation. The Flowering Date1 (FD1) gene has a large effect on the photoperiodic response of flowering time, but the molecular basis for the effect of this locus is undetermined. The present study delimited the FD1 locus to a 17.1 kb sequence, containing a single gene, an E1 ortholog (VaE1). A comparison between Vigna angularis ‘Shumari’ (photoperiod insensitive) and ‘Acc2265’ (photoperiod sensitive) identified 29 insertions/deletions and 178 SNPs upstream of VaE1 in the FD1 locus. VaE1 expression in ‘Acc2265’ was greater under long-day than short-day conditions, whereas VaE1 expression in ‘Shumari’ was lower regardless of day length. These findings suggested that responsible gene of FD1 is a VaE1, which acts as a floral repressor by being upregulated in response to long-day conditions. The inability to upregulate VaE1 under long-day conditions was linked to its ability to flower under these conditions. These results provide greater understanding of the molecular control of a flowering date and clues enabling the breeding of adzuki bean at higher latitudes.     

Concentration of cephalothin in body fluids and tissue samples of Thoroughbred horses

Cephalothin (CET) concentrations in body fluids (plasma, synovial fluid, pleural fluid, peritoneal fluid, and aqueous humor) and tissue samples (bone, lung, jejunum, hoof, and subcutaneous tissue) were investigated to consider the treatment of infectious diseases in horses. CET 22 mg/kg body weight was intravenously administered to 12 horses. Samples were collected from four different horses at 1, 3, and 5 hr after administration. The CET concentration in body fluids other than aqueous humor was maintained above the MIC₉₀ values of Streptococcus zooepidemicus and Staphylococcus aureus until 5 hr, but it was not maintained above that of S. aureus in bone. CET (22 mg/kg twice a day) is effective for septic arthritis, pleuritis, and peritonitis caused by gram-positive bacteria but ineffective for osteomyelitis.     

Structural determination of the oligosaccharides in the milk of a giant anteater (Myrmecophaga tridatyla)

There appears to be strong evidence supporting four major clades of placental mammals: (i) Afrotheria; (ii) Xenarthea; (iii) Euarchontoglires; and (iv) Laurasiathera. This is the first study in which the carbohydrates have been analyzed in the milks of Xenarthea. Our aim was to clarify whether the saccharides of giant anteater milk resemble those of other eutherian species, especially of the Asian elephant, which is one of the Afrotherea. We found that lactose is a dominant saccharide in this milk, as it is in that of most eutherians, and that the milk contains smaller amounts of oligosaccharides, whose structures were determined as Gal(α1‐3)Gal(β1‐4)Glc (isoglobotriose), Neu5Ac(α2‐6)Gal(β1‐4)Glc (6'‐N‐acetylneuraminyllactose), Neu5Gc(α2‐6)Gal(β1‐4)Glc (6'‐N‐glycolylneuraminyllactose), Neu5Ac(α2‐6)Gal(β1‐4)GlcNAc(β1‐3)Gal(β1‐4)Glc (LST c) and Neu5Gc(α2‐6)Gal(β1‐4)GlcNAc(β1‐3)Gal(β1‐4)Glc. This pattern of milk carbohydrates is rather close to that of the milks of other eutherian species. It is notable that the milk contained oligosaccharides with Neu5Gc residues but no oligosaccharides containing α(2‐3) linked Neu5Ac residues such as Neu5Ac(α2‐3)Gal(β1‐4)Glc.     

Correlation between skeletal muscle fiber type and free amino acid levels in Japanese Black steers

Free amino acids are important components of tastants and flavor precursors in meat. To clarify the correlation between muscle fiber type and free amino acids, we determined the concentrations of various free amino acids and dipeptides in samples of different muscle tissues (n = 21), collected from 26‐month‐old Japanese Black steers (n = 3) at 2 days postmortem. The proportions of the myosin heavy chain (MyHC), slow (MyHC1) and fast (MyHC2) isoforms were determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). The contents of free amino acids and dipeptides were measured by high performance liquid chromatography (HPLC). The MyHC isoform composition varied among the tissue samples. The MyHC1 proportion ranged from 6.9% ± 3.9% to 83.3% ± 16.7%. We confirmed that there was a strong positive correlation between MyHC1 composition and total free amino acid concentrations, including those for two dipeptides. Among the 31 measured free amino acids and dipeptides, 11 showed significant positive correlations and five showed significant negative correlations with MyHC1 composition. These results suggest that a high MyHC1 content induces high free amino acid contents in bovine muscles possibly because of greater oxidative metabolism. This high level of free amino acids could contribute to the intense flavor of meat that is rich in slow‐twitch fibers.     

Hypoglycemia associated with disseminated metastatic tonsillar squamous cell carcinoma producing insulin‐like growth factor‐I in a Pomeranian dog

A 13‐year‐old spayed female Pomeranian dog was presented for persistent, severe hypoglycemia (37 mg/dL; reference interval [RI] 75‐128 mg/dL). Progressive nonregenerative anemia (hematocrit 23.3%‐15.9%; RI 37.0%‐55.0%) and severe thrombocytopenia (36 000/µL; RI 200‐500 000/µL) were also noted. The serum insulin concentration was low (0.24 ng/mL; RI 0.302‐1.277 ng/mL). Computed tomography revealed multiple splenic nodules (1‐6 mm in diameter) and several hepatic nodules (7.6, 12 mm in diameter). Ultrasound‐guided fine‐needle aspiration of the splenic and hepatic nodules revealed low numbers of epithelial cells with mild cellular atypia, suggestive of a metastatic epithelial tumor, but the primary site was unknown at that time. On careful oral examination under general anesthesia, an enlarged right tonsil was noted grossly, and histopathologic examination of the tonsil diagnosed squamous cell carcinoma. Bone marrow aspirates and biopsies of the splenic and hepatic nodules were performed; all samples were diagnosed as metastatic carcinoma on histopathologic examination. No nodules were present in the pancreas, despite careful palpation during exploratory laparotomy. On immunohistochemistry, the neoplastic cells were positive for cytokeratin AE1/3 and insulin‐like growth factor (IGF)‐I but were negative for chromogranin A, PGP9.5, insulin, and inconclusive for IGF‐II. This is the first report of a primary IGF‐I‐producing squamous cell carcinoma in the tonsil of a dog with metastases to bone marrow, liver, and spleen, resulting in hypoglycemia.     

Knockout mouse production assisted by Blm knockdown

Production of knockout mice using targeted embryonic stem cells (ESCs) is a powerful approach for investigating the function of specific genes in vivo. Although the protocol for gene targeting via homologous recombination (HR) in ESCs is already well established, the targeting efficiency varies at different target loci and is sometimes too low. It is known that knockdown of the Bloom syndrome gene, BLM, enhances HR-mediated gene targeting efficiencies in various cell lines. However, it has not yet been investigated whether this approach in ESCs is applicable for successful knockout mouse production. Therefore, we attempted to answer this question. Consistent with previous reports, Blm knockdown enhanced gene targeting efficiencies for three gene loci that we examined by 2.3–4.1-fold. Furthermore, the targeted ESC clones generated good chimeras and were successful in germline transmission. These data suggest that Blm knockdown provides a general benefit for efficient ESC-based and HR-mediated knockout mouse production.     

Microbial biomass and nitrogen transformations in surface soils strongly acidified by volcanic hydrogen sulfide deposition in Osorezan, Japan

Volcanic acidification has created unique ecosystems that have had to adapt to the acidic environments in volcanic regions. To characterize the primary microbial properties of strongly acidified soils in such environments, we investigated microbial biomass, nitrogen transformations and other relevant chemical properties in the surface soils of solfatara and forests from Osorezan, a typical volcanic region in Japan, and compared the results to common Japanese forest soils. Soil microbial biomass C (MBC) and N (MBN) were determined using the chloroform fumigation–extraction method. Potential net N mineralization and net nitrification were measured in aerobic laboratory incubations. Long-term acidification in the Osorezan soils by volcanic hydrogen sulfide deposition caused low soil pH (3.0–3.8), base cation deficiency and increased concentrations of toxic ions such as Al³⁺. The proportions of MBC to total carbon (MBC/TC ratio) and MBN to total nitrogen (MBN/TN ratio) were lower than those in common Japanese forest soils. The extreme acidic conditions may have inhibited microbial survival in the Osorezan acid soils. Net N mineralization occurred at rates comparable to those in common Cryptomeria japonica forest soils, probably because of the presence of acid-tolerant soil microorganisms. Net nitrification was completely inhibited and autotrophic ammonia oxidizers were not detected by the MPN method. The inhibition of nitrification prevents nitrogen leaching from the soils, thus maintaining a nitrogen cycle in the volcanic acid region in which     (and NH₃) is recycled among microorganisms and plants.