De novo assembly, functional annotation, and marker development of Asian pear (Pyrus pyrifolia) fruit transcriptome through massively parallel sequencing.

This study investigated the Asian pear transcriptome using the RNA-Seq normalized fruit cDNA library to create a transcriptomic resource for unigene and marker discovery. Following the removal of lowquality reads, 127,085,054 trimmed reads were assembled de novo to yield 37,649 non-redundant unigenes with an average length of 599 bp. Alternative splicing events were detected in 4121 contigs. A total of 30,560 single nucleotide polymorphisms (SNPs) and 7443 simple sequence repeat (SSR) makers were obtained. Approximately 21,449 (56.9%) unigenes were categorized into three gene ontology groups; 3682 (9.8%) were classified into 25 cluster of orthologous groups; and 10,451 (27.8%) were assigned to six Kyoto Encyclopedia of Genes and Genomes pathways. Differentially expressed genes were investigated using the reads per kilobase of the exon model per million reads methodology. A total of 546 unigenes showed significant differences in expression levels at different fruit developmental stages. Gene ontology categories associated with various aspects, including carbohydrate metabolic processes, transmembrane transport, and signal transduction, were enriched with genes with divergent expressions. These Pyrus pyrifolia transcriptome data provide a rich resource for the discovery and identification of new genes. Furthermore, the numerous putative SSRs and SNPs detected in this study will be important resources for the future development of a linkage map or of marker-assisted breeding programs for the Asian pear.

A survey of Gnathostoma larvae in fresh water fish in the valley of the Yangtze River and morphological characteristics of the recovered larvae.

Investigations of the prevalence of larval gnathostomes in fresh water fishes were carried out at the southeastern Yangtze Valley, People's Republic of China, in the periods of October 1989 and November 1990. Fishes were collected from Shanghai, Chenchiang, Nanching, Chiuchiang and Nanchang districts in 1989. Additional sampling in Shanghai district was done at Kunshan, Tien-shanfu, Chingpu and Nanhui. Species of fishes collected were Channa argus (110), Siniperca chuatsi (24) and Silurus asotus (2). Muscle tissue of the fishes was dissected into small pieces, sliced and then examined under a dissecting microscope. The viscera were pooled by species in groups of 4 or 5 individuals, homogenized, and were then digested overnight in artificial gastric-juice at 37 degrees C. Four encysted larvae were recovered from the muscle tissue of four C. argus. Thirty-four larvae were obtained from digestion of viscera. A total of 38 larvae were recovered. Eighteen of 38 larvae were examined morphologically and they were able to be divided into three types by their body length; 5 early third-stage larvae (0.58-0.86 mm), 12 third-stage larvae (1.12-2.61 mm), and one advanced third-stage larva of 4.86 mm. Light and scanning electron microscopy revealed that the former two types had characteristics of Gnathostoma hispidum and the last one had those of G. spinigerum. In 1990, we investigated fish near Hongtze-hu and Tai-hu lakes. A total of 553 fishes belonging to 12 genera and 12 species were examined. Seventeen larvae were recovered from the viscera of G. argus and Monopterus albus. These larvae were identified as G. hispidum.

[A human infection of the cestode, Diphyllobothrium nihonkaiense Yamane et al., 1986].

A mature cestode, obtained from a 49-year-old man in Fukuoka, southern Japan, was examined. The worm was about 70 cm in length without scolex. The largest segment was 1.8 x 0.8 cm. Cirrus sac lay at an obtuse angle (about 150 degrees) to seminal vesicle. The eggs were 62.06 +/- 9.40 x 43.33 +/- 6.43 microns and the shell thickness 1.0-1.5 microns, with round, shallow and sparsely distributed surface pits ranging 0.8-2.0 microns in diameter. The above features suggested that this worm was identified as the cestode, Diphyllobothrium nihonkaiense.

A comparative ultrastructural and histochemical study of the metacercarial cyst walls of four species of Paragonimus (Troglotrematidae: Trematoda).

The metacercarial cyst walls of Paragonimus westermani, P. miyazakii, P. ohirai, and P. iloktsuenensis were examined using ultrastructural and histochemical techniques. The cyst walls of P. westermani, P. miyazakii, and P. ohirai were found to have five distinct layers, whereas the wall of P. iloktsuenensis had only two. The so-called outer cyst wall recognized on light microscopy by Miyazaki (1961) was composed of layers I-III and the so-called inner cyst wall comprised layers IV and V. The outermost layer (I) consisted of collagen fibers and probably originated from the host. Layer III detached easily from layer IV on removal of the cysts from the host tissues. Layer IV was composed of proteoglycans, and layer V consisted of protein alone. A regular hexagonal pattern in layer V appeared to be characteristic of P. westermani. Although the basic morphological patterns observed in the layers constituting the cyst walls were similar in all species examined, the thickness of each layer was apparently different. This characteristic seems to be a suitable criterion for the identification of metacercarial cysts of Paragonimus species.

A survey of Gnathostoma larvae in fresh water fish in the valley of the Yangtze River and morphological characteristics of the recovered larvae.

Investigations of the prevalence of larval gnathostomes in fresh water fishes were carried out at the southeastern Yangtze Valley, People's Republic of China, in the periods of October 1989 and November 1990. Fishes were collected from Shanghai, Chenchiang, Nanching, Chiuchiang and Nanchang districts in 1989. Additional sampling in Shanghai district was done at Kunshan, Tien-shanfu, Chingpu and Nanhui. Species of fishes collected were Channa argus (110), Siniperca chuatsi (24) and Silurus asotus (2). Muscle tissue of the fishes was dissected into small pieces, sliced and then examined under a dissecting microscope. The viscera were pooled by species in groups of 4 or 5 individuals, homogenized, and were then digested overnight in artificial gastric-juice at 37 degrees C. Four encysted larvae were recovered from the muscle tissue of four C. argus. Thirty-four larvae were obtained from digestion of viscera. A total of 38 larvae were recovered. Eighteen of 38 larvae were examined morphologically and they were able to be divided into three types by their body length; 5 early third-stage larvae (0.58-0.86 mm), 12 third-stage larvae (1.12-2.61 mm), and one advanced third-stage larva of 4.86 mm. Light and scanning electron microscopy revealed that the former two types had characteristics of Gnathostoma hispidum and the last one had those of G. spinigerum. In 1990, we investigated fish near Hongtze-hu and Tai-hu lakes. A total of 553 fishes belonging to 12 genera and 12 species were examined. Seventeen larvae were recovered from the viscera of G. argus and Monopterus albus. These larvae were identified as G. hispidum.