Discovery and early evaluation of new chemical entities

Drug discovery is a costly and time-consuming process, with very few novel molecular entities approved for clinical use today. With the advancement of computational chemistry, integrated X-ray crystallography and nuclear magnetic resonance spectroscopy technology, more and more potential therapeutic agents for the treatment of human diseases are discovered. Furthermore, multiple medicinal chemistry approaches have been developed in support of early drug discovery. However, there is still much can be done in the early phase of drug discovery to improve the chances of success of a drug candidate. This paper reviews the discovery and evaluation of new chemical entities in the early stages of drug development.

Variation in seed and seedling traits and their relations to geo-climatic factors among populations in Yunnan Pine(Pinus yunnanensis)

Differences in seed germination and seedling growth among populations of Pinus yunnanensis Franch. were quantified to provide information for use in the regeneration, reforestation, and improvement of this species. Seed germination and seedling growth traits at the nursery stage were investigated at the population level. We evaluated relationships between pairs of measured traits as well as the association between measured traits and geo- climatic variables including longitude, latitude, elevation, temperature and precipitation. Seedling growth showed significant differences although a low magnitude of variation was found in the seed germination traits among the populations. Some populations with strong and stable growth （e.g., the Baoshan population） may be selected as superior seed sources for regeneration and reforestation. Germination percentage was negatively correlated with elevation, and positively with precipitation. In addition, germination index, vigor index and seedling height were positively correlated with precipitation. Seed germination index, cotyledon number and length, and seedling diameter were significantly and positively correlated with seed weight. Strong correlations between pairs of traits will be helpful in early evaluations for the selection of certain prominent traits.

Relationship between the number of tapping-induced secondary laticifer lines and rubber yield among Hevea germplasm

The lack of suitable early selection parameters means that traditional rubber breeding for yield is time consuming and inefficient. Laticifer is a tissue specific fo natural rubber biosynthesis and storage in rubber tree. The number of the secondary laticifers in the trunk bark tissues is positively correlated with rubber yield in the matured rubber trees that are regularly tapped. In the present study the rubber yield from 280 of 4–5 year-old virgin trees from7 cross combinations was compared with the number o newly differentiated secondary laticifers caused by tapping. Results showed that the number of tapping induced lines of secondary laticifers varied in differen germplasm and was positively related to the rubber yield indicating this could be used as a suitable parameter fo early evaluation of yield potential of rubber trees.