Comparison of Hydrostatic Filtration Dialysis with Ultracentrifugation Methods for the Identification and Proteomic Profiling of Urinary Extracellular Vesicles.

BACKGROUND: Urinary extracellular vesicles (UEVs) carry rich markers of their parent cells, so they can serve as possible biomarkers of kidney diseases. METHODS: In this study, we isolated urinary extracellular vesicles from five individuals using a simple, clinically applicable method called hydrostatic filtration dialysis (HFD) and compared it to the gold-standard ultracentrifuga-tion (UC) with transmission electron microscopy (TEM). We also employed a proteomic approach using pooled human urine samples from the same five individuals to profile the protein composition of UEVs to evaluate the effectiveness of these two methods. RESULTS: Notably, using TEM, we found that all isolations contained 0 - 400 nm vesicles with the traditionally reported morphology, although the TEM results showed that the UEVs isolated from HFD compared to those from UC are larger and more extensive. We obtained a total of 2,564 UEV proteins in the two methods. We showed a large overlap (2,185 > 85%) between the proteins identified by both isolation methods. The result also showed that the obtained proteins in extracellular vesicles, which are isolated with these methods, are consistent with the results in currently available databases. However, in the associated gene ontologies, the enriched proteins found by the two methods showed some differences. CONCLUSIONS: The HFD method is clinically feasible and allows large-scale protein profiling of UEV biomarkers. The results of this study also provide valuable UEV protein data from the methodological comparison, which might be valuable to other researchers.

Succession of sulfur bacteria during decomposition of cyanobacterial bloom biomass in the shallow Lake Nanhu: An ex situ mesocosm study.

Previous studies of the dynamics of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) have focused on deep stratified lakes. The objective of this study is to present an in-depth investigation of the structure and dynamics of sulfur bacteria (including SRB and SOB) in the water column of shallow freshwater lakes. A cyanobacterial bloom biomass (CBB)-amended mesocosm experiment was conducted in this study, in which water was taken from a shallow eutrophic lake with sulfate levels near 40 mg L-1. Illumina sequencing was used to investigate SRB and SOB species involved in CBB decomposition and the effects of the increases in sulfate input on the water column microbial community structure. The accumulation of dissolved sulfide (∑H2S) produced by SRB during CBB decomposition stimulated the growth of SOB, and ∑H2S was then oxidized back to sulfate by SOB in the water column. Chlorobaculum sequences (the main SOB species in the study) were significantly influenced by increases in sulfate input, with relative abundance increasing approximately four-fold in treatments amended with 40 mg L-1 sulfate (referred to as 40S) when compared to the treatment without additional sulfate addition (referred to as CU). Additionally, an increase in SOB number was observed from day 26-37, concurrent with the decrease in SRB number, indicating the succession of sulfur bacteria. These findings suggest that biological sulfur oxidation and succession of sulfur bacteria occur in the water column during CBB decomposition in shallow freshwater ecosystems, and the increases in sulfate input stimulate microbial sulfur oxidation.

Qualitative and quantitative analysis of chemical constituents of Centipeda minima by HPLC-QTOF-MS & HPLC-DAD.

A high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) method in both positive and negative ion modes was established to investigate the major constituents in the ethanolic extract of Centipeda minima (EBSC). Twelve common components including flavones and their glycosides, phenolic and polyphenolic acids, and sesquiterpene lactone were identified in ten batches of samples based on comparison with the retention time and accurate mass of external standards (mass accuracy within 3ppm) or the fragmentation patterns of tandem MS. Meanwhile, a simple, accurate and reliable HPLC-DAD method was also developed to determine the content of 10 chemical markers simultaneously. Results obtained from method validations including linearity, accuracy and precision showed that this new method is reliable and robust. Isochlorogenic acid A and brevilin A were found to be the most abundant in the ethanol extract of EBSC and could be served as markers for quality control of EBSC.

Localization of PS9 in Rice Ragged Stunt Oryzavirus and Its Role in Virus Transmission by Brown Planthopper.

A cDNA of rice ragged stunt oryzavirus(RRSV) coding for its protein PS9 was prepared and expressed in E.coli as a fusion protein then purified and cleaved by factor-Xa to a 38kD polypeptide. Using the IgG of the antiserum raised against the expressed fusion protein the gold immuno-labelling experiments provided a direct evidence that the 38kD polypeptide is one of the major proteins forming the virus spikes. Virus transmission experiments in brown planthopper fed with PS9 showed the inhibition of transmission of virus by the PS9 protein suggesting that the spike proteins of the virus may be essential for the virus infection.