Molecular and biological characterization of <Emphasis Type="Italic">Chrysanthemum stem necrosis virus</Emphasis> isolates from distinct regions in Japan

Three isolates of Chrysanthemum stem necrosis virus (CSNV) were obtained from chrysanthemum plants in distinct regions of Japan in 2006 and 2007. All the original host plants showed severe necrotic symptoms on the leaves and stems. Amino acid sequence data of the nucleocapsid protein genes of the three isolates (CbCh07A, TcCh07A, and GnCh07S) showed high identities with those of two other CSNV isolates, HiCh06A L1 from Japan and Chry1 from Brazil. Furthermore, for the first time the complete nucleotide sequence of the S RNA was determined for CSNV (isolate HiCh06A). In phylogenetic analysis based on the non-structural protein genes from the genus Tospovirus, HiCh06A L1 was placed in the same genetic group as Tomato spotted wilt virus (TSWV) and Impatiens necrotic spot virus. Host range examination for isolates HiCh06A L1 and CbCh07A showed that green pepper (cv. ‘Kyoyutaka’, ‘Saitamawase’, ‘Tosakatsura’, ‘L3 sarara’ and ‘L3 miogi’) and tomato (cv. ‘Sekaiichitomato’) were systemically susceptible hosts, whereas TSWV-resistant Solanaceae species, Capsicum chinense, Lycopersicon peruvianum and a TSWV-resistant cultivar of green pepper (cv. TSR miogi), were resistant.     

Early origin and recent expansion of Plasmodium falciparum

The emergence of virulent Plasmodium falciparum in Africa within the past 6000 years as a result of a cascade of changes in human behavior and mosquito transmission has recently been hypothesized. Here, we provide genetic evidence for a sudden increase in the African malaria parasite population about 10,000 years ago, followed by migration to other regions on the basis of variation in 100 worldwide mitochondrial DNA sequences. However, both the world and some regional populations appear to be older (50,000 to 100,000 years old), suggesting an earlier wave of migration out of Africa, perhaps during the Pleistocene migration of human beings.     

Current classification of Ralstonia solanacearum and genetic diversity of the strains in Japan

Ralstonia solanacearum is the causal organism of bacterial wilt of more than 200 species representing 50 families of plants in tropical, subtropical, and warm temperate regions in the world. Traditionally classified into five races based on differences in host range, R. solanacearum has also been grouped into six biovars on the basis of biochemical properties. With recent developments in molecular biology, various DNA-based analyses have been introduced and used to confirm that this binary system does not completely represent the diversity within R. solanacearum strains. Therefore, a new hierarchical classification scheme has been suggested, which defines R. solanacearum as a species complex and reorganized the concept of the species as a monophyletic cluster according to a phylogenetic analysis based on genomic sequence data. Here we discuss the current bacterial wilt situation and genetic relationships based on the recent classification system of Japanese R. solanacearum strains as well as worldwide strains. We also review the genetic, biochemical, and pathological characteristics of R. solanacearum strains, in particular, those affecting potato and Zingiberaceae plants as distinctly important pathogens in relation to continuously problematic and recent emergent diseases in Japan.     

Identification of endotrypanum species from a sloth,a squirrel and Lutzomyia sandflies in ecuador by PCR amplification and sequencing of the mini-exon gene

PCR amplification and nucleotide sequencing of the mini-exon gene revealed that four strains isolated from a sloth (Choloepus hoffmanni), a squirrel (Sciurus granatensis) and two sandflies (Lutzomyia hartmanni) in Ecuador were indistinguishable from Endotrypanum monterogeii. Another strain isolated from Lu. hartmanni showed the high sequence similarity to E. schaudinni. Since three of these strains have been previously identified as Leishmania (Viannia) equatorensis, the results demonstrate that L. (V.) equatorensis is genetically closely related to the genus Endotrypanum. The present study also indicates that Endotrypanum species are distributed in arboreal animals and sandflies in Ecuador, and that mini-exon gene amplification is useful for epidemiological studies of Leishmania and Endotrypanum in the New World.     

New potyvirus isolated from <Emphasis Type="Italic">Cryptotaenia japonica</Emphasis>

 A potyvirus, for which the name Japanese hornwort mosaic virus (JHMV) is proposed, was isolated from Japanese hornwort plants (Cryptotaenia japonica) with mosaic disease symptoms. The virus was used to inoculate mechanically 34 plants belonging to 33 species of 10 families. Of these species seven from two families were infected. Faint chlorotic spots appeared on the inoculated leaves of Chenopodium quinoa and C. amaranticolor, but no systemic infection occurred in these plants. JHMV systemically infected only Umbelliferae plants; they did not infect 26 other species in eight families. JHMV was transmitted in a nonpersistent manner by aphids (Myzus persicae). The virus was a flexuous rod-shaped particle about 750 nm in length. Sequencing the nucleotides in the 3′ terminal region of JHMV revealed that the coat protein contains 280 amino acids with a molecular mass of 32.2 kDa. The nucleotide sequence of the coat protein of JHMV had the highest similarity with that of Zantedeschia mosaic virus (83.3%) compared to those of other potyviruses (57.0%–64.9%). An antiserum against JHMV reacted strongly with JHMV and weakly with Potato virus Y. These results indicate that JHMV is a new potyvirus. Received: September 9, 2002 / Accepted: November 7, 2002 RID="*" ID="*" The nucleotide sequence determined in this work appears in the DDBJ/EMBL/GenBank nucleotide sequence databases with the accession number AB081518     

Identification of novel tumour‐associated antigens in canine mammary gland tumour

Canine mammary gland tumour (MGT) is the most common neoplasm in female dogs and has similar biological characteristics to human MGT. Spontaneous canine MGT is a more attractive clinical model in oncological research than that of the murine experimental model. Tumour‐associated antigens (TAAs), which are produced in tumour cells, are applied as tumour markers, tumour vaccine antigens and molecular targets of therapeutic drugs. In this study, we have primarily identified 13 different TAAs of canine MGT by serological immunoscreening of cDNA expression library. The results of serological mini‐arrays of identified antigens showed that CCDC41 antigen specially reacted with 35% of sera from MGT‐dogs and did not react with control sera. We also found that HSPH1 mRNA expression levels increased significantly in MGT tissues. These findings will contribute to the development of diagnostic technologies and translational target therapies for dogs. Clinical relevance : HSPH1, which is strongly expressed in the tumour tissue, will be a possible vaccine antigen of canine MGT.     

Total and available tryptophan requirement of Nile tilapia,Oreochromis niloticus,fingerlings

The dietary total and available requirement of tryptophan of Nile tilapia fingerlings was determined using linear regression analysis. Six hundred fish (3.4 ± 0.0 g) were fed diets containing 296.4 g/kg of crude protein and 14.1 MJ/kg of digestible energy. Five extruded diets containing 2.5, 3.0, 3.4, 3.8 and 4.2 g/kg of total tryptophan were evaluated. Fish were fed four times a day during 45 days. Final body weight, weight gain, feed intake, feed conversion ratio and net protein utilization of fish fed Trp 3.4 and Trp 3.8 diets were improved compared to fish fed Trp 2.5 and Trp 4.2 diets. No significant differences in survival rate, whole‐body moisture and ash were observed. Whole‐body amino acid profile of fish fed different diets did not differ statistically (p > .05). Fish fed Trp 3.0 and Trp 3.4 diets showed higher tryptophan retention compared to fish fed Trp 2.5 and Trp 4.2 diets. Excepting blood glucose, no effects of dietary tryptophan on haematological parameters were observed. The dietary total tryptophan requirement of Nile tilapia fingerlings based on weight gain was estimated to be 3.4 g/kg (11.0 g/kg of dietary crude protein) or 3.0 g/kg of available tryptophan (11.0 g/kg of dietary digestible protein).