Temporal distribution and pathogenicity of the predominant tomato‐infecting begomoviruses in Taiwan

Between 1998 and 2009, the four tomato‐infecting begomovirus species detected in Taiwan were Ageratum yellow vein Hualien virus (AYVHuV), Tomato leaf curl Taiwan virus (ToLCTWV), Tomato yellow leaf curl Thailand virus (TYLCTHV) and a newly defined species Tomato leaf curl Hsinchu virus (ToLCHsV). AYVHuV was detected occasionally in 2003 and ToLCHsV only in 2000–2001, whilst ToLCTWV was detected throughout the period. TYLCTHV was first detected in 2005. Between 1998 and 2005, >99% of the begomovirus‐positive samples were infected with ToLCTWV. In 2007 in western Taiwan, 16% of the positive samples were infected with ToLCTWV, 35% with TYLCTHV and 49% with mixed infection (ToLCTWV/TYLCTHV). In contrast, in eastern Taiwan the proportions were 84% ToLCTWV, 2% TYLCTHV and 14% mixed infection. However, throughout Taiwan in 2008–2009, most positive samples were either identified as TYLCTHV (51%) or mixed infection (ToLCTWV/TYLCTHV; 41%), and only 8% were ToLCTWV. This shows a clear trend of shifting from ToLCTWV to TYLCTHV and mixed infection over a short time period in Taiwan. Sequence analyses indicated that tomato‐infecting AYVHuV, an apparent recombinant between ToLCTWV and AYVHuV from Ageratum, represents a new strain Hsinchu. TYLCTHV Taiwan isolates were highly similar to each other, whereas ToLCTWV isolates had greater diversity and were classified into three strains which had one country‐wide and two local distributions. ToLCTWV and TYLCTHV were confirmed as monopartite and bipartite begomoviruses, respectively, by agroinfection followed by transmission with Bemisia tabaci biotype B. In addition, TYLCTHV was found to be mechanically transmissible together with viral DNA‐B.     

Phenotypic and molecular characterization of isolates of Ornithobacterium rhinotracheale from chickens and pigeons in Taiwan

Forty Ornithobacterium rhinotracheale (ORT) strains were isolated from 28 chickens and 12 pigeons for the first time in Taiwan. All isolates reacted positively in the p-nitrophenyl-beta-D-galactopyranoside (PNPG) and oxidase tests, showing an API 20NE identification system biocode 0-0-2-0-0-0-4. All the pigeon isolates and 85.7% (24 of 28) of the chicken isolates belonged to serotype A. Compared to the ORT ATCC 51464 strain, 14.3% (4 of 28) of chicken isolates and 58.3% (7 of 12) of pigeon isolates showed smaller colonies after 72 hr incubation. Most of the chicken isolates (22 of 28), but none of the pigeon isolates, could agglutinate chicken and pigeon red blood cells. There appears to be a correlation that ORT isolates with a larger colony size tend to be more able to agglutinate red blood cells than the ORT isolates with a smaller colony size. A majority of isolates was sensitive to amoxicillin, ampicillin, ceftiofur, penicillin, and oxytetracycline. The 16S ribosomal RNA (rRNA) sequences of 23 Taiwanese ORT isolates showed high identity (98%-100%) to sequences in GenBank. Phylogenetic analysis of these sequences showed that pigeon isolates formed a distinctive cluster, while chicken isolates and all other 16S rRNA sequences obtained from GenBank belonged to another two clusters. The results indicate that pigeon ORT isolates are different from most chicken isolates in regard to a number of phenotypic and molecular traits.     

The Combinatorial Effect of Different Equex STM Paste Concentrations,Cryoprotectants and the Straw‐Freezing Methods on the Post‐Thaw Boar Semen Quality

This study was to evaluate the combinatorial effect (14 treatments, A–N) of different Equex STM paste concentrations, cryoprotectants and the straw‐freezing method on the post‐thaw boar semen quality. Two ejaculates were collected from each of nine boars (three boars from each of three breeds). Semen was diluted in extenders with different concentrations of Equex STM paste and different cryoprotectants [glycerol or dimethylacetamide (DMA)] before cryopreserving via liquid nitrogen or dry ice. Motility, viability, percentage of spermatozoa with intense acrosomal staining and with normal morphology of post‐thaw sperm were evaluated. The qualities of thawed semen were best preserved in treatment H (extender with 0.5% Equex STM paste and 5% glycerol and freezing by dry ice) and were worst in treatment B (extender with 0% Equex STM paste and 5% DMA and freezing by dry ice). Significant difference (p < 0.05) was present in post‐thawed sperm motility (63% vs 27%), sperm viability (70% vs 33%) and sperm acrosomal integrity rate (68% vs 29%) between treatments H and B. However, sperm proportion with normal morphology showed no significant difference among treatments (66% vs 66%; p > 0.05). Moreover, statistical analysis suggests that no significant difference was present in semen quality among breed or individual donors (p > 0.05). These findings suggest that Equex STM paste improved the cryosurvival efficiency of boar sperm, and the favourable straw‐freezing method changes between glycerol and DMA.     

钙和水杨酸对亚适温弱光下黄瓜幼苗光合酶活性和基因表达的影响

为了探明钙和水杨酸对亚适温弱光下黄瓜幼苗光合作用的调控机理,以‘津优3号’黄瓜为试材,用10 mmol ? L-1氯化钙（CaCl2）和1 mmol ? L-1水杨酸（SA）喷施预处理幼苗,每天喷1次,连续3 d,之后置于光照培养箱内进行亚适温弱光处理（18 ℃/12 ℃,PFD 100 μmol ? m-2 ? s-1）。结果表明：亚适温弱光可使黄瓜幼苗生长量大幅度下降,光合速率（Pn）以及核酮糖–1,5–二磷酸羧化/加氧酶（Rubisco）、果糖–1,6–二磷酸酯酶（FBPase）、甘油醛–3–磷酸脱氢酶（GAPDH）、果糖1,6–二磷酸醛缩酶（FBA）、转酮醇酶（TK）的活性与其mRNA表达明显降低,但CaCl2和SA预处理的黄瓜幼苗的降低幅度明显较小,可见钙和水杨酸可以通过提高光合酶的活性及其基因表达,缓解亚适温弱光对黄瓜幼苗光合作用的影响,增强其对亚适温弱光的适应性。     

Genetic relationships of Rhododendron (Ericaceae) in Taiwan based on the sequence of the internal transcribed spacer of ribosomal DNA

Summary

The genetic relationships of 20 Rhododendron species in Taiwan was determined based on the sequence of the internal transcribed spacer (ITS) region of ribosomal DNA. Sequences of the complete ITS region including ITS1, 5.8S rDNA, and ITS2, were obtained by direct sequencing of polymerase chain reaction (PCR)-amplified fragments. Gaultheria itoana was used as an outgroup. Aligned sequences of ITS1 and ITS2 from the 21 taxa resulted in 493 characters. According to the dendrogram, six main clusters were classified among the 20 species of the genus Rhododendron in Taiwan. Rhododendron oldhamii, R. nakaharai, R. taiwanalpinum, R. simsii, R. lasiostylum, R. rubropilosum, R. breviperulatum, R. kanehirai, and R. noriakianum were grouped with R. longiperulatum in cluster I. Rhododendron lamprophyllum was grouped with R. ovatum in cluster II. Rhododendron pseudochrysanthum, R. morri, R. hyperythrum, and R. rubropunctatum were grouped with R. formosanum in cluster III. In addition, R. mariesii, R. ellipticum and R. kawakamii formed three independent clusters. In this study, the findings based on ITS sequences are in agreement with the systematics of Rhododendron.     

Identification of sex-specific polymorphic sequences in the goat amelogenin gene for embryo sexing

Amelogenin (AMEL) is a conserved gene located on the sex chromosomes of mammals. It is involved in the formation of enamel, which is the hard, white material that forms the protective outer layer of each tooth. In this study, we first cloned and determined the intron sequences of the goat AMELX and AMELY genes from female and male ear tissues. The polymorphic AMEL alleles were further analyzed by PCR-based RFLP and Southern blot hybridization analyses. Results showed that intron 5 nucleotide sequences of the goat AMELY gene contains multiple deletions/insertions and shares only 48.5% identity to intron 5 of the goat AMELX gene. Based on the polymorphic AMEL intron sequences, a set of sex-specific triplex primers was designed to PCR amplify a single fragment of 264 bp from the X chromosome of female goats and 2 fragments of 264 and 206 bp from the X and Y chromosomes, respectively, of male goats. An increased sensitivity for sex determination was reached with a single blastomere at the blastula stage isolated from goat embryos. A total of 43 goat embryos were used to estimate a 100% accuracy rate of this method confirmed by chromosomal karyotyping and live births. The embryo sexing technique has been successfully applied in different strains of goats including Alpine, Saanen, Nubian, and Taiwan goats.     

C-terminal region of Candida rugosa lipases affects enzyme activity and interfacial activation

Candida rugosa contains several lipase (CRLs) genes, and CRLs show diverse enzyme activity despite being highly homologous across their entire protein family. Previous studies found that LIP4 has a high esterase activity and a low lipolytic activity and lacks interfacial activation. To investigate whether the C-terminal region of the CRLs mediates enzymatic activity, chimeras were generated in which the C-terminus of LIP4 from either residue 374, 396, 417, or 444 to residue 534 was swapped with the corresponding peptide from the isoform LIP1. A chimeric lipase containing the C-terminus from 396 to 534 of LIP1 on a LIP4 scaffold showed activity similar to that of commercial CRL on triolein, and lipolytic activity increased 2-6-fold over that of LIP4. Moreover, interfacial activation was also observed in the chimeric lipase. To improve its enzymatic properties, a novel glycosylation site was added at residue 314. The new glycosylated lipase showed improved thermostability and enhancement in enzymatic activity, indicating its potential for use in further application.     

Molecular characterization of the CP gene and 3'UTR of Chilli veinal mottle virus from South and Southeast Asia

Twenty-four isolates of Chilli veinal mottle virus (ChiVMV) from China, India, Indonesia, Taiwan and Thailand were analysed to determine their genetic relatedness. Pathogenicity of virus isolates was confirmed by induction of systemic mosaic and/or necrotic ringspot symptoms on Capsicum annuum after mechanical inoculation. The 3' terminal sequences of the viral genomic RNA were determined. The coat protein (CP) coding regions ranged from 858 to 864 nucleotides and the 3' untranslated regions (3'UTR) from 275 to 289 nucleotides in length. All isolates had the inverted repeat sequence GUGGNNNCCAC in the 3'UTR. The DAG motif, conserved in aphid-transmitted potyviruses, was observed in all isolates. All 24 isolates were considered as belonging to ChiVMV because of their high CP amino acid and nucleotide identity (more than 94·8 and 89·5%, respectively) with the reported ChiVMV isolates including the pepper vein banding virus (PVBV), the chilli vein-banding mottle virus (CVbMV) and the CVbMV Chiengmai isolate (CVbMV-CM1). Based on phylogenetic analysis, ChiVMV isolates including all 24 isolates tested, PVBV, CVbMV and CVbMV-CM1 can be classified into three groups. In addition, a conserved region of 204 amino acids with more than 90·2% identity was identified in the C terminal of the CP gene of ChiVMV and Pepper veinal mottle virus (PVMV), and may explain the serological cross reaction between these two viruses. The conserved region may also provide useful information for developing transgenic resistance to both ChiVMV and PVMV.     

北京地区春玉米螟害产量损失估计方法及防治指标的商榷

根据1962—1964年北京地区12块春播玉米地心叶期卵和卵虫(第一代)成活率資料,并参考国内对螟害与玉米产量損失关系的研究成果,提出了春玉米上因玉米螟为害而造成的产量損夫估計方法和药剂防治的参考指标。心叶期卵的平均成活率及其标准誤为57.4±2.9％,卵块的脫落是死亡的主要原因。幼虫期的平均成活率及其标准誤为5.64±0.89％。这两个平均成活率的变異系数都比较小,相关分析表明,百株着卵量与成长幼虫数是相关的。故可职利用卵和幼虫的平均成活率由着卵密度来估計成长幼虫密度。心叶期卵和幼虫的合計平均成活率及其标准誤为3.4±0.51％。在95％可靠性时的置信区間为3.4±1.173％,卵块的平均粒数为31.7粒。若职单株平均一虫所造成的产量損失率为5％計,可用丁式来估計产量損失: 产量損失％=[(心叶期百株累計卵块数×31.7)×(0.034±0.012)]×0.05 在經济核算士,作者初步認为职損失率1.5％作为防治标准比較合适。以此推算,欲达到这一損失率,心叶期百株累計卵块应为28块(用平均成活率計算)至21块(用成活率上界計算)。一般可定为24块。根据心叶期百株累計卵块数与累計着卵株百分率或百株高峯卵块数之間存在的相关,百株累計24块卵,相当于累計着卵株率28％,或百株高峯卵块6块。在实践上就可以用它們作为心叶期的防治指标。