Evaluation of Antifungal Phenolics from Helianthus tuberosus L. Leaves against Phytophthora capsici Leonian by Chemometric Analysis.

Phytophthora capsici Leonian causes destructive economical losses in pepper production, and a promising source of natural fungicides- Helianthus tuberosus leaves was reported. The antifungal activities of different extracts and compounds from H. tuberosus leaves against the phytopathogen, P. capsici Leonian, were examined by chemometric analysis, including HPLC-MS/MS and multivariate data analyses. Principal component analysis and orthogonal partial least squares-discriminate analysis were applied to examine the four groups of H. tuberosus leaves samples, including crude extracts obtained by different methods, including refluxing, macerating, and refluxing under vacuum; four fractions, namely, petroleum ether (PE), chloroform (Chl), ethyl acetate (EA), and n-butanol (NB) fractions; the samples of three H. tuberosus cultivars; and the samples at three growth stages of cultivar Nan Yu. The phenolics contents were categorized based on 3,5-Dicaffeoylquinic acid (3,5-DiCQA), 1,5-Dicaffeoylquinic acid (1,5-DiCQA), 3-O-Caffeoylquinic acid (3-CQA), and 4,5-Dicaffeoylquinic acid (4,5-DiCQA), which were predominant in all the samples. Antifungal activity assay revealed that Chl and NB fractions were more active against P. capsici Leonian with lower IC50(half of maximal inhibitory concentration) values, whereas partial least squares-discriminate analysis suggested caffeoylquinic acid isomer(4-CQA), methyl-quercetin glycoside(MQG), and caffeic acid(CA) might be the main active components in H. tuberosus leaves against P. capsici Leonian. Furthermore, microscopic evaluation demonstrated structural deformities in P. capsici Leonian treated with Chl and NB fractions, indicating the antifungal effects of H. tuberosus leaves. These results imply that H. tuberosus leaves with a high concentration of phenolics might be a promising source of natural fungicides.

Immune escape of avian oncogenic Marek's disease herpesvirus and antagonistic host immune responses.

Marek's disease virus (MDV) is a highly pathogenic and oncogenic alpha herpesvirus that causes Marek's disease (MD), which is one of the most important immunosuppressive and rapid-onset neoplastic diseases in poultry. The onset of MD lymphomas and other clinical diseases can be efficiently prevented by vaccination; these vaccines are heralded as the first demonstration of a successful vaccination strategy against a cancer. However, the persistent evolution of epidemic MDV strains towards greater virulence has recently resulted in frequent outbreaks of MD in vaccinated chicken flocks worldwide. Herein, we provide an overall review focusing on the discovery and identification of the strategies by which MDV evades host immunity and attacks the immune system. We have also highlighted the decrease in the immune efficacy of current MD vaccines. The prospects, strategies and new techniques for the development of efficient MD vaccines, together with the possibilities of antiviral therapy in MD, are also discussed.