Development of genic SSR marker resources from RNA-seq data in Camellia japonica and their application in the genus Camellia.

Camellia is a genus of flowering plants in the family Theaceae, and several species in this genus have economic importance. Although a great deal of molecular makers has been developed for molecular assisted breeding in genus Camellia in the past decade, the number of simple sequence repeats (SSRs) publicly available for plants in this genus is insufficient. In this study, a total of 28,854 potential SSRs were identified with a frequency of 4.63 kb. A total of 172 primer pairs were synthesized and preliminarily screened in 10 C. japonica accessions, and of these primer pairs, 111 were found to be polymorphic. Fifty-one polymorphic SSR markers were randomly selected to perform further analysis of the genetic relationships of 89 accessions across the genus Camellia. Cluster analysis revealed major clusters corresponding to those based on taxonomic classification and geographic origin. Furthermore, all the genotypes of C. japonica separated and consistently grouped well in the genetic structure analysis. The results of the present study provide high-quality SSR resources for molecular genetic breeding studies in camellia plants.

Inter- and intra-manufacturer variability in pharmaceutical grades and lots of xanthan gum.

A pharmaceutical formulation typically contains one or more excipients in addition to the active pharmaceutical ingredient(s). Though excipients have been considered inert components of a formulation, variability in their properties has been shown to affect the performance of drug dosage forms and delivery systems. This study investigates the inter- and intra-manufacturer variability among different NF grades and lots of xanthan gum made by two manufacturers. As many formulators rely on compendial standards to monitor and control the variability of excipients, this study focuses on the adequacy of the NF specifications, in particular the viscosity specification, to discern the variability in solution properties of different pharmaceutical grades and lots of xanthan gum. All the grades and lots in this study were NF grade materials. Xanthan gum solutions were prepared in accordance with NF test methodology and were rheologically evaluated using a rotational rheometer. Both steady shear measurements and small amplitude oscillatory measurements were carried out on 1% w/w xanthan gum solutions. Results showed significant inter- and intra-manufacturer variability among the NF grades and lots of xanthan gum that was not reflected in the NF viscosity test specifications.