Original antigenic sin and apoptosis in the pathogenesis of dengue hemorrhagic fever

Dengue virus presents a growing threat to public health in the developing world. Four major serotypes of dengue virus have been characterized, and epidemiological evidence shows that dengue hemorrhagic fever (DHF), the more serious manifestation of the disease, occurs more frequently upon reinfection with a second serotype. We have studied dengue virus-specific T-cell responses in Thai children. During acute infection, few dengue-responsive CD8+ T cells were recovered; most of those present showed an activated phenotype and were undergoing programmed cell death. Many dengue-specific T cells were of low affinity for the infecting virus and showed higher affinity for other, probably previously encountered strains. Profound T-cell activation and death may contribute to the systemic disturbances leading to DHF, and original antigenic sin in the T-cell responses may suppress or delay viral elimination, leading to higher viral loads and increased immunopathology.     

Wolbachia infections of tephritid fruit flies: molecular evidence for five distinct strains in a single host species

Endosymbiotic bacteria of the genus Wolbachia are widespread among arthropods and can induce cytoplasmic incompatibility, thelytokous parthenogenesis, male-killing or feminization in their hosts. Here, we report phylogenetic relationships of Wolbachia in tephritid fruit flies based on wsp gene sequences. We also report, for the first time, five distinct strains of Wolbachia in Bactrocera ascita sp. B. Four of the five Wolbachia strains found in this species were in the same groups as those found in other tephritid fruit flies, suggesting possible horizontal transmission of Wolbachia from other fruit flies into B. ascita sp. B. The unreliability of wsp-specific group primers demonstrated in this study suggests that these primers might be useful only for preliminary identification of Wolbachia. Final determination of group affiliation needs to be verified with wsp sequence data. Received: 12 December 2001 / Accepted: 11 January 2002     

A new subgenus, Microidium, of Oidium (Erysiphaceae) on Phyllanthus spp.

Powdery mildew fungi found on leaves, shoots, and stems of Phyllanthus acidus, P. amarus, and P. reticulatus proved to be a fungus having morphology unique in the Erysiphaceae. Light micrographs of a new germination pattern are added to discuss differences to other four germination patterns of the powdery mildews. The rDNA sequences (28S and 18S regions) of the fungi found on Phyllanthus spp. form a distinct monophyletic clade strongly supported by bootstrap (100%) in 18S + 28S trees, which indicates that the fungus is an isolated fungal group among the Erysiphaceae in tribal level. Because we cannot find the teleomorphic state of this fungus, a new subgenus Microidium of anamorphic genus Oidium is proposed to accommodate this organism.     

Dengue and Zika Virus Cross-Reactive Human Monoclonal Antibodies Protect against Spondweni Virus Infection and Pathogenesis in Mice

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Identification of Japanese Astraeus, based on morphological and phylogenetic analyses

To clarify the diversity of Astraeus in Japan, 35 collections of Astraeus basidiomata from Japan and Thailand were examined for their morphological characteristics and the nucleotide sequences of the rDNA ITS region and compared with several worldwide Astraeus species. Japanese Astraeus specimens were separated into two groups based on basidiome size, shape of exoperidium, and ornamentation and size of basidiospores. The phylogenetic tree analyses supported the separation, and the morphological groups belonged to different clades. The Japanese Astraeus group 1, morphologically matched to Astraeus hygromerticus var. koreanus, showed the closest phylogenetic relationship with Astraeus hygrometricus from North American and Mediterranean regions, suggesting that the Astraeus group 1 can be indentified as A. hygrometricus var. koreanus. Another Astraeus group, group 2, morphologically matched to A. hygrometricus s.l., showed a distinct monophyletic clade that was separated from A. hygrometricus complexes, indicating an undescribed species.     

SSR markers in transcripts of genes linked to post-transcriptional and transcriptional regulatory functions during vegetative and reproductive development of Elaeis guineensis

Background  

The oil palm (Elaeis guineensis Jacq.) is a perennial monocotyledonous tropical crop species that is now the world's number one source of edible vegetable oil, and the richest dietary source of provitamin A. While new elite genotypes from traditional breeding programs provide steady yield increases, the long selection cycle (10-12 years) and the large areas required to cultivate oil palm make genetic improvement slow and labor intensive. Molecular breeding programs have the potential to make significant impacts on the rate of genetic improvement but the limited molecular resources, in particular the lack of molecular markers for agronomic traits of interest, restrict the application of molecular breeding schemes for oil palm.     

Reduced neutralization of SARS-CoV-2 B.1.1.7 variant by convalescent and vaccine sera

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