Bacterial Wilt of Russell Prairie Gentian Caused by <Emphasis Type="Italic">Burkholderia caryophylli</Emphasis>

A new bacterial disease of Russell prairie gentian (Eustoma grandiflorum) was found in Fukuoka Prefecture, Japan, in 1997. This disease was characterized by wilting and yellowing of the foliage. A cross section of the stem of a diseased plant revealed a tan to yellow-brown discoloration of the vascular tissue. A nonfluorescent, aerobic, Gram-negative bacterium was consistently isolated from infected plants. The bacteriological characteristics of 10 isolates of the bacterium coincided with those of the reference strains of Burkholderia caryophylli that were isolated from carnations. The bacterium, as well as the reference strains, attacked Russell prairie gentian and carnation after artificial inoculation and reproduced the symptoms similar to those after natural infections. On the basis of bacteriological characteristics and pathogenicities, the bacterium was identified as B. caryophylli. This is the first report of a disease caused by B. caryophylli on Russell prairie gentian ; therefore, bacterial wilt of Russell prairie gentian is proposed as the name of the disease. Received 5 April 2000/ Accepted in revised form 11 July 2000     

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.     

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.     

Inoculation of Lupinus luteus with White Root Rot Fungus, Rosellinia necatrix, to Estimate Virulence

An inoculation method using Lupinus luteus was developed for estimating virulence of isolates of the white root rot fungus, Rosellinia necatrix Prillieux. Fungal cultures grown on pieces of mulberry twigs were placed in contact with the hypocotyl of 3-week-old seedlings growing in pots of soil. Disease development was uniform and reproducible in repeated experiments. Of 24 isolates with double-stranded RNA, eight were weakly virulent. This method is useful throughout the year for estimating virulence of many isolates of the fungus and for screening for hypovirulent isolates. Received 2 March 2001/ Accepted in revised form 25 May 2001     

D-Alanine-D-Alanine Ligase Gene (ddl) of Erwinia chrysanthemi Strain EC16 I. Isolation and Gene Dosage Effect on Pectate Lyase Synthesis

New regulatory gene for pectate lyase (Pel) production of Erwinia chrysanthemi strain EC16 was searched by observing the gene dosage effect of each cosmid library in Pel production. From this survey, a cosmid clone, p5A, had reduced in Pel production under both inducing and non-inducing conditions and caused less tissue maceration of potato tubers. The 2.64-kb HindIII fragment from p5A was found to be responsible for this phenotype and to contain one major ORF consisting of 1107 nucleotides, which had homology with ddlA (49.6%) and ddlB (49.6%) of Escherichia coli and with ddlA (44.6%) of Salmonella typhimurium. These genes had been shown to encode D-alanine-D-alanine ligase (Ddl), an enzyme which is involved in the synthesis of peptidoglycan. This ORF encodes 368 amino acid residues and its molecular weight is estimated to be 43 kDa. This ORF of EC16 could complement ddl deficient mutant of Escherichia coli. Received 15 May 2002/ Accepted in revised form 20 June 2002     

气相色谱-串联质谱检测蔬菜中氟吡菌酰胺及其代谢物残留

采用气相色谱-串联质谱（GC-MS/MS）技术建立了同时检测7种类型蔬菜中氟吡菌酰胺及其代谢物残留的分析方法。样品采用乙腈提取,无水硫酸镁和氯化钠盐析后,经分散固相萃取（PSA）净化,GC-MS/MS检测。结果表明:在0.01、0.1和1 mg/kg 3个添加水平下,氟吡菌酰胺及其代谢物2-（三氟甲基）苯甲酰胺（BZM）的平均回收率在80%~108%之间,相对标准偏差（RSD）在1.5%~8.4%之间。氟吡菌酰胺及其代谢物在7种蔬菜中的检出限（LOD）（S/N=3）分别为2.17~3.13 μg/kg和1.22~2.04 μg/kg,两者的定量限（LOQ）均为0.01 mg/kg。该方法操作简便、稳定和快速,可以满足大部分蔬菜中氟吡菌酰胺及其代谢物的定性与定量分析要求。     

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。     

Evaluation of the air sac volume of penguins with respiratory diseases using computed tomography

Captive penguins with respiratory diseases exhibit advanced pathological conditions upon the appearance of clinical signs. Therefore, the successful treatment of respiratory diseases remains difficult after the onset of clinical signs, leading to high mortality rates. In this study, we measured air sac volume using computed tomography (CT) to evaluate the respiratory condition of penguins. In a regular quarterly health checkup, blood samples were collected from 45 penguins housed at an aquarium in Hokkaido, Japan. A total of 12 penguins with abnormal blood parameters underwent CT. The air sac volumes were calculated in three-dimensional CT, and the scatter plots of the air sac volumes and body weights were analyzed. No correlation was found between the air sac volume and body weight in both the gentoo and king penguins. Two gentoo penguins with infiltration and one king penguin with multiple nodules on CT were tentatively diagnosed with aspergillosis and treated with oral administration of itraconazole. Follow-up CT examination was performed until the outcome: healed or died. The mean air sac volumes of the two gentoo penguins, which recovered after treatment, increased from 273.9 and 329.0 cm³ before healing to 449.0 and 424.6 cm³ after healing, respectively. Meanwhile, the air sac volume of the king penguin, which subsequently died, decreased from 1,556.9 to 920.6 cm³ despite treatment. Changes of the air sac volume in the same individual could be useful for evaluating the respiratory condition of penguins.