Further studies in the genus Caulokaempferia (Zingiberaceae) in Thailand with the description of two new species

Two new species of Caulokempferia from Thailand, C. amplexicaule and C. pedemontana are described and illustrated. The biogeography and the diversity of the genus are discussed.     

Sirindhomia, a new orchid genus from Southeast Asia

The new orchid genus Sirindhomia , named after H. R. H. Princess Maha Chakri Sirindhorn of Thailand, is established to accommodate three species from Thailand (Chiang Mai and Tak provinces), Myanmar (Shan State), and China (Yunnan province). Two new species are described and a new combination, based on Habenaria monophylla Collett & Hemsl., is made; all of the three species are illustrated, and a distribution map is provided. Sirindhomia belongs to subtribe Orchidinae and has an overall similarity with Ponerorchis, Hemipilia , and Amitostigma. However, it significantly differs in its column morphology which is more reminiscent of that found in the vegetatively distinct genus Orchis. The new species, Sirindhomia pulchella and S. mirabilis , seem to be local endemics, as they are only known from the Thai mountains Doi Chiang Dao and Khao Hua Mot, respectively. Sirindhomia monophylla , on the other hand, is known from a very large part of the range of the genus. All Sirindhomia species known are restricted to limestone mountains at 800–2200 m alt., mainly growing in rock crevices and among scrub as well as on grassy slopes. They flower from April to June.     

Oleic acid Enhances Dengue Virus But Not Dengue Virus-Like Particle Production from Mammalian Cells

Despite the recent introduction of a commercial vaccine, the mosquito-transmitted dengue virus is still a worldwide public health problem. Based on the live attenuated vaccine strategy, the commercial vaccine has a less than optimal protective profile. Virus-like particles (VLPs) offer an attractive alternate vaccination strategy due to the effectively native presentation of epitopes in the absence of any infectious genetic material. However, the production of amounts of VLP in a platform that can support commercial development remains a major obstacle. This study generated two DENV 2 VLPs [codon-optimized and chimeric DENV/Japanese encephalitis virus (JEV)] and directly compared yields of these constructs by western blotting and dot blot hybridization. The effect of oleic acid supplementation, a process known to increase DENV production in natural infection, was also investigated. Results showed that the chimeric construct gave a two- to threefold higher yield than the codon-optimized construct and that while oleic acid increased DENV virion production in natural infection, it inhibited VLP production. These results suggest that further optimization of DENV VLP expression is possible, but it will require more understanding of how native DENV infection remodels the host cell machinery.