Possible Role of ZPAC,Zygote-specific Proteasome Assembly Chaperone,During Spermatogenesis in the Mouse

In the mammalian testis, the ubiquitin-proteasome system plays important roles in the process that promotes the formation of mature sperm. We recently identified zygote-specific proteasome assembly phaperone (ZPAC), which is specifically expressed in the mouse gonads and zygote. ZPAC mediates a unique proteasome assembly pathway in the zygote, but the expression profile and function of ZPAC in the testis is not fully understood. In this study, we investigated the possible role of ZPAC during mouse spermatogenesis. First, we analyzed the expression of ZPAC and 20S proteasome subunit α4/PSMA7 in the adult mouse testis. ZPAC and α4 were expressed in spermatogonia, spermatocytes, and round spermatids. In elongating spermatids, ZPAC was expressed until step 10, whereas expression of α4 persisted until step 12. We then examined the expression profile of ZPAC and α4 in a mouse model of experimental unilateral cryptorchidism. Consistent with appearance of morphologically impaired germ cells following cryptorchidism, the ZPAC protein level was significantly decreased at 4 days post induction of experimental cryptorchidism (D4) compared with the intact testis, although the amount of α4 protein persisted at least until D10. Moreover, intense ZPAC staining was co-localized with staining of annexin V, an early indicator of apoptosis in mammalian cells, in germ cells of cryptorchid testis, but ZPAC was also expressed in germ cells showing no detectable expression of annexin V. These results suggest that ZPAC plays a role during spermatogenesis and raises the possibility that 20S proteasome mediated by ZPAC may be involved in the regulation of germ cell survival during spermatogenesis.     

Reappraisal of Ashby's hypothesis on heterosis of physiological traits in maize,Zea mays L

Summary The present study was undertaken to reappraise the materials and methods used by various reports discussing Ashby's hypothesis on heterosis of physiological traits in maize. The review of 15 reports led to the conclusion that both Ashby's hypothesis and the subsequent refutations of the hypothesis were based on insufficient evidence. New experiments using suitable pollination techniques and an appropriate statistical analysis enabled us to confirm Ashby's hypothesis.This work is supported by the Green Energy Program' (GEP84-II-6-6) promoted by MAFF.     

Unrecognized difficult airway management during anesthesia in two brachycephalic dogs with narrow cricoid cartilage

Difficulty in airway management during anesthesia was noted in a 10-year-old, castrated, male Pekingese dog and a 13-year-old male French Bulldog. They showed strong resistance during tracheal tube insertion through the subglottic lumen. Therefore, the airway was secured by using a small endotracheal tube or supraglottic airway device. Computed tomography scan revealed a markedly narrower vertical dimension of the cricoid cartilage compared to that seen in common brachycephalic breeds. Posterior glottis was relatively more accessible for translaryngeal intubation in the present cases. Our findings showed that brachycephalic airway syndrome may be associated with narrow cricoid cartilage. To the best of our knowledge, this is the first clinical case report of airway management during anesthesia in dogs with narrow cricoid cartilage.     

Prevalence of serum antibodies to Toxoplasma gondii in free-ranging cats on Tokunoshima Island,Japan

The prevalence of Toxoplasma gondii infection in free-ranging cats on Tokunoshima Island was assessed by testing 125 serum samples using anti-T. gondii IgG indirect enzyme-linked immunosorbent assay. The overall seropositivity rate was 47.2% (59/125). Seropositivity rates in cats with body weight >2.0 kg (57.4%) were significantly higher than in those with body weight ≤2.0 kg (12.5%, P<0.01). Analysis of the number of seropositive cats by settlement revealed the presence of possibly-infected cats in 17 of 23 settlements, indicating the widespread prevalence of T. gondii on the island. This is the first study to show the seroprevalence of T. gondii in free-ranging cats on Tokunoshima Island. The information revealed in this paper will help to prevent the transmission of T. gondii among cats and also in both wild and domestic animals and humans on the island.     

Comparison of protein chemical and physicochemical properties of rapeseed cruciferin with those of soybean glycinin

Rapeseeds contain cruciferin (11S globulin), napin (2S albumin), and oleosin (oil body protein) as major seed proteins. The effects of oil expression and drying conditions on the extraction of these proteins from rapeseed meal were examined. The conditions strongly affected the extraction of oleosin and only weakly affected the extraction of cruciferin and napin. The protein chemical and physicochemical properties of cruciferin, the major protein present, were compared with those of glycinin (soybean 11S globulin) under various conditions. In general, cruciferin exhibited higher surface hydrophobicity, lower thermal stability, and lower and higher solubility at mu= 0.5 and mu = 0.08, respectively, than did glycinin. At the pHs (6.0, 7.6, and 9.0) and ionic strengths (mu= 0.08 and 0.5) examined, the emulsifying ability of cruciferin was worse than that of glycinin, except at mu= 0.08 and pH 7.6. The emulsifying abilities of cruciferin and glycinin did not correlate with thermal stability and surface hydrophobicity. Higher protein concentration, higher heating temperature, higher pH, and lower ionic strength were observed to produce harder gels from cruciferin. Gel hardness partly correlated with the structural stability of cruciferin.     

Lactobacillus hayakitensis, L. equigenerosi and L. equi, predominant lactobacilli in the intestinal flora of healthy thoroughbreds

To detect the predominant lactobacilli in the intestinal flora of healthy thoroughbreds, we isolated lactobacilli from the feces of nine thoroughbreds (five males and four females; 0–15-year-old). The isolated lactobacilli comprise 17 species (37 strains), and they were classified into five groups: Lactobacillus salivarius (6 species), L. reuteri (6 species), Lactobacillus delbrueckii (3 species), L. buchneri (1 species) and L. vitulinus (1 species). On the basis of 16S rRNA gene sequences, we identified 3 other phylogenetic relatives belonging to the genus Lactobacillus . These results suggest that the intestinal flora of thoroughbreds may comprise many species of the genus Lactobacillus . Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analyses of the 340-bp fragments of the 16S rRNA genes from the same nine fecal samples showed that L. hayakitensis , L. equigenerosi and L. equi are contained in all the samples, suggesting that these species are predominant lactobacilli in the intestinal flora of thoroughbreds.     

稻曲病菌离体培养体系的构建与优化

稻曲病是水稻穗期的一种重要病害,严重影响稻米的产量和品质。稻曲病菌Ustilaginoidea virens 在离体培养条件下生长缓慢,严重制约了杀菌剂室内生测试验的观察和高效筛选。本研究以稻曲病菌培养基为研究对象,通过筛选、组合和优化固体培养体系的氮源、碳源、凝固剂以及阳离子浓度,以期构建适合稻曲病菌生长的室内培养体系。结果发现:在5种常见的商品化培养基中,稻曲病菌的生长速率仅为0.7~2.3 mm/d;而在18种配制培养基中,有77%的培养基对稻曲病菌表现出不同程度的生长促进效应,其中蛋白胨蔗糖结冷胶 (PSGG) 培养基的促进效果最显著 (P < 0.05),生长速率达3.4 mm/d,且其对不同地理分布的稻曲病菌菌株均有生长促进效应。此外,在以结冷胶作为凝固剂的培养基中添加质量分数为0.02%的硫酸镁 (Mg2+),可有效提高培养基的凝固程度,且对菌丝体的生长速率无影响。在适合稻曲病菌生长的PSGG培养基中,蛋白胨和蔗糖是合适的氮源和碳源组合,结冷胶是合适的凝固剂。此研究结果可提高室内培养稻曲病菌的生长速率,为进一步理解稻曲病菌在离体条件下的生长机制及提高室内杀菌剂生测试验的效率提供了重要参考。     

Restriction of bovine herpesvirus 1 (BHV-1) growth in non-permissive cells beyond the expression of immediate early genes

Mouse BALB/3T3-A31-1-1 (A31) cells are non-permissive to bovine herpes virus-1 (BHV-1) but permissive to pseudorabies virus (PrV). The promoter activity of the immediate early gene of BHV-1 (BICP4) was very weak when compared with that of PrV in A31 cells. Infectious BHV-1 genomic DNA co-transfected into A31 cells with plasmids expressing BICP4 and BICP0 by a strong promoter failed to yield any progeny virus. Growth of BHV-1 in non-permissible A31 cells is restricted in many phases of the growth. The fact that expression of BICP4 and/or BICP0 in A31 cells does not improve the yield of progeny virus from infectious BHV-1 genomic DNA suggests that some more growth restrictions exist beyond the expression of BHV-1 immediate early proteins.     

Preconditioning prevents ischemia-induced neuronal death through persistent Akt activation in the penumbra region of the rat brain

A brief period of ischemia, i.e. preconditioning of the middle cerebral artery territory, induces ischemic tolerance reducing the cerebral infarction volume caused by subsequent lethal ischemia. Nevertheless, little is known about the molecular mechanisms underlying this phenomenon. In the present study, we examined the involvement of the activation of Akt, a serine/threonine kinase, in the cerebral ischemic tolerance. Western blot analysis showed that Akt was activated in both non-preconditioned and preconditioned groups after ischemia for 1 hr, but the activation was long-lasting in the preconditioned rats. Immunohistochemical analysis demonstrated that the preconditioning-induced preventive effect on a rapid decrease in the activation level of Akt was due to the persistent activation of Akt in the penumbra region. In addition, TUNEL staining demonstrated that the preconditioning treatment inhibited the augmentation of neuronal death probably through apoptosis in the penumbra region to prevent the spread of infarction. Since the activation of Akt has been reported to protect cells from stress, the present results suggest that the preconditioning-induced persistent activation of Akt in the penumbra region plays an important role in ischemic tolerance of the brain.