Chilling injury mechanism of hardy kiwifruit (Actinidia arguta) was revealed by proteome of label-free techniques.

Refrigeration is an important method to extend shelf life of hardy kiwifruit. However, the inappropriate storage temperature can lead to chilling injury in the fruit. We found that firmness, total soluble solids, and total polyphenolic content of the fruit exposed to 0℃ environment were apparently lower, and titratable acidity content, browning rate, weight loss rate, electrolyte leakage, proline content, and malondialdehyde content were higher obviously than 4℃. A total of 244 differentially expressed proteins were found result from differential temperatures, among which 113 were up-regulated and 131 were down-regulated. Subcellular localization results presented that the differentially expressed proteins which were affected by low temperature were located in cytoplasmic, chloroplast, nuclear, mitochondrial, plasma membrane, and extracellular. Kyoto Encyclopedia of Genes and Genomes analysis showed that the differentially expressed proteins were mainly participated in synthesis of citrate cycle, oxidative phosphorylation, fatty acid biosynthesis, and starch and sucrose metabolism. Protein-protein interaction results revealed that central proteins interaction points respectively are 30S ribosomal proteins, 30S ribosomal protein S7, chloroplastic, cell division cycle 5-like protein, 50S ribosomal protein, ribosomal protein, ribosomal protein L6 protein, and SRP54 subunit protein. The quality deviations of all identified peptides were mainly distributed within 10 ppm, and MS2 has an ideal andromeda score, with more than 87.82% peptide scores above 60 points, and the median peptide score of 99.28 points. Therefore, the results of this study provide important information for new gene revelation and gene interaction relationship in hardy kiwifruit of chilling injury. PRACTICAL APPLICATIONS: Inhibition of cold damage in hardy kiwifruit under low temperature is very important work for the development of its storage industry. However, many qualities of fruit will deteriorate after long-term cold storage and those biological activities of the fruits are regulated by proteins. It is, therefore, of great significance to reveal the key proteins caused cold damage in hardy kiwifruit. Moreover, the study results could provide a scientific information for the quality improvement and genetic modification of hardy kiwifruit.

Adenovirus type 3 induces platelet activation in vitro.

In the present study, we aimed to investigate platelet activation induced by adenovirus type 3 (HAdV3) in vitro. Platelet-rich plasma (PRP) or whole blood was incubated with or without HAdV at various concentrations. Platelet aggregation, platelet counting, fibrinogen and expression of platelet membrane antigens (CD41a and CD62P) were determined following incubation with HAdV for different periods of time. The results demonstrated that HAdV at the concentrations of 109-1011 vp/ml enhanced adenosine diphosphate (ADP) or ristocetin-induced platelet aggregation, however did not alter the platelet count. Infection with HAdVs also reduced fibrinogen level. P-selectin and CD41a appeared rapidly on the surface after platelets were incubated with HAdVs in vitro for 30 min. In conclusion, HAdVs may induce activation of platelets and lead to a pre-thrombotic state of peripheral blood. This finding may aid in the development of measures to prevent severe HAdV infection.

Structure-based high-throughput epitope analysis of hexon proteins in B and C species human adenoviruses (HAdVs).

Human adenoviruses (HAdVs) are the etiologic agent of many human infectious diseases. The existence of at least 54 different serotypes of HAdVs has resulted in difficulties in clinical diagnosis. Acute respiratory tract disease (ARD) caused by some serotypes from B and C species is particularly serious. Hexon, the main coat protein of HAdV, contains the major serotype-specific B cell epitopes; however, few studies have addressed epitope mapping in most HAdV serotypes. In this study, we utilized a novel and rapid method for the modeling of homologous proteins based on the phylogenetic tree of protein families and built three-dimensional (3D) models of hexon proteins in B and C species HAdVs. Based on refined hexon structures, we used reverse evolutionary trace (RET) bioinformatics analysis combined with a specially designed hexon epitope screening algorithm to achieve high-throughput epitope mapping of all 13 hexon proteins in B and C species HAdVs. This study has demonstrated that all of the epitopes from the 13 hexon proteins are located in the proteins' tower regions; however, the exact number, location, and size of the epitopes differ among the HAdV serotypes.

Anti-adenovirus activities of shikonin, a component of Chinese herbal medicine in vitro.

Radix Lithosperm eyrthrorhizon is a common prescription compound in traditional Chinese medicine. Shikonin is a major component of Radix Lithospermi and has various biological activities. We have investigated the inhibitory effect of shikonin on the growth of adenovirus type 3 (AdV3) in vitro. The antiviral function of shikonin against AdV3 and its virus inhibition ratio were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method (MTT). The expression of hexon protein in AdV3 was determined by immunofluorescence assay using laser scanning confocal microscopy (LSCM) and Western blot analysis. In addition, the rate of apoptosis in cells infected by AdV3 was determined by flow cytometry. Shikonin (0.0156-1 µM) inhibited growth of AdV3 in a concentration-dependent manner with a virus inhibition rate of 23.8-69.1%. Expression of hexon protein in AdV3 was higher in the virus control group than in the shikonin-treated groups as determined by immunofluorescence assay and Western blotting (p<0.05). The rate of shikonin-treated HeLa cell apoptosis had a statistically significant decrease with increasing concentration of drug (p<0.05). Our data demonstrate that shikonin possesses anti-AdV3 capabilities and that the potential antiviral mechanism might involve inhibiting the degree of apoptosis and hexon protein expression of AdV.