Membrane vesicles nucleate mineralo-organic nanoparticles and induce carbonate apatite precipitation in human body fluids.

Recent studies indicate that membrane vesicles (MVs) secreted by various cells are associated with human diseases, including arthritis, atherosclerosis, cancer, and chronic kidney disease. The possibility that MVs may induce the formation of mineralo-organic nanoparticles (NPs) and ectopic calcification has not been investigated so far. Here, we isolated MVs ranging in size between 20 and 400 nm from human serum and FBS using ultracentrifugation and sucrose gradient centrifugation. The MV preparations consisted of phospholipid-bound vesicles containing the serum proteins albumin, fetuin-A, and apolipoprotein A1; the mineralization-associated enzyme alkaline phosphatase; and the exosome proteins TNFR1 and CD63. Notably, we observed that MVs induced mineral precipitation following inoculation and incubation in cell culture medium. The mineral precipitates consisted of round, mineralo-organic NPs containing carbonate hydroxyapatite, similar to previous descriptions of the so-called nanobacteria. Annexin V-immunogold staining revealed that the calcium-binding lipid phosphatidylserine (PS) was exposed on the external surface of serum MVs. Treatment of MVs with an anti-PS antibody significantly decreased their mineral seeding activity, suggesting that PS may provide nucleating sites for calcium phosphate deposition on the vesicles. These results indicate that MVs may represent nucleating agents that induce the formation of mineral NPs in body fluids. Given that mineralo-organic NPs represent precursors of calcification in vivo, our results suggest that MVs may initiate ectopic calcification in the human body.

Fur-dependent MrkHI regulation of type 3 fimbriae in Klebsiella pneumoniae CG43.

Type 3 fimbriae play a crucial role in Klebsiella pneumoniae biofilm formation, but the mechanism of the regulation of the type 3 fimbrial operon is largely unknown. In K. pneumoniae CG43, three regulatory genes, mrkH, mrkI and mrkJ, are located downstream of the type 3 fimbrial genes mrkABCDF. The production of the major pilin MrkA is abolished by the deletion of mrkH or mrkI but slightly increased by the deletion of mrkJ. Additionally, quantitative RT-PCR and a promoter-reporter assay of mrkHI verified that the transcription of mrkHI was activated by MrkI, suggesting autoactivation of mrkHI transcription. In addition, sequence analysis of the mrkH promoter region revealed a putative ferric uptake regulator (Fur) box. Deletion of fur decreased the transcription of mrkH, mrkI and mrkA. The expression of type 3 fimbriae and bacterial biofilm formation were also reduced by the deletion of fur. Moreover, a recombinant Fur was found to be able to bind both promoters, with higher affinity for P(mrkH) than P(mrkA), implying that Fur controls type 3 fimbriae expression via MrkHI. We also proved that iron availability can influence type 3 fimbriae activity.

Differential sensing of serine and tyrosine with aligned CdS nanowire arrays based on pH-dependent photoluminescence behavior.

The differential sensing of tyrosine and serine is achieved with well-aligned CdS nanowire arrays by exploring the pH-dependent photoluminescence behavior of the nanowire arrays toward exposure to the two amino acid solutions. The contrasting trend in photoluminescence (PL) intensity with respect to variations in analyte concentration observed at pH 11 served as the check point for the present differential sensing. The application format of the nanowire array is better suited for further sensing device assembly than that of nanocrystal suspensions.

The change pattern of SP and NO in the portal vein during the RAIR.

PURPOSE: To investigate the change pattern of substance P (SP) and nitric oxide (NO) in the portal vein during the recto-anal inhibitory reflex (RAIR), and its physiological significance; the influence of external splanchnic nerve (ESN) of rectum and anus to the RAIR. MATERIALS AND METHODS: Seventy-six rats divided into five groups according to the distance of Foley's tube in the rectum and whether or not to cut off ESN supply to the rectum and anal canal, to measure the values of SP and NO in the portal vein during the RAIR. RESULTS: The stimulus in rectum can cause change of SP and NO in portal vein. The greatest increase of SP is at the 6-cm group. The 6-cm group with total ESN supply had significant difference compared with the 4-cm group before and after the ESN supply and control group were cut (P<0.01). After cutting-off ESN, the increase of SP in the portal vein reduced significantly when compared with the normal ESN supply at the 6-cm group (P<0.05). The greatest change of NO is at the 4-cm group with total ESN. There were significant differences among the 4- and 6-cm groups and control group. After cutting off ESN, the increase of NO was lower than with the intact ESN. There were still differences between the 4- and 6-cm groups and control group(P<0.05). CONCLUSION: The stimulations at different points of the rectum cause different SP and NO change in the portal vein. This may be the explanation why the stimulation on the different points on the rectum induces different change pattern of RAIR from the neurotransmitters point. The ESN supplies of the rectum and anal canal have an influence on the change of SP and NO in the portal vein during RAIR.

Pleomorphic bacteria-like structures in human blood represent non-living membrane vesicles and protein particles.

Although human blood is believed to be a sterile environment, recent studies suggest that pleomorphic bacteria exist in the blood of healthy humans. These studies have led to the development of "live-blood analysis," a technique used by alternative medicine practitioners to diagnose various human conditions, including allergies, cancer, cardiovascular disease and septicemia. We show here that bacteria-like vesicles and refringent particles form in healthy human blood observed under dark-field microscopy. These structures gradually increase in number during incubation and show morphologies reminiscent of cells undergoing division. Based on lipid analysis and Western blotting, we show that the bacteria-like entities consist of membrane vesicles containing serum and exosome proteins, including albumin, fetuin-A, apolipoprotein-A1, alkaline phosphatase, TNFR1 and CD63. In contrast, the refringent particles represent protein aggregates that contain several blood proteins. 16S rDNA PCR analysis reveals the presence of bacterial DNA in incubated blood samples but also in negative controls, indicating that the amplified sequences represent contaminants. These results suggest that the bacteria-like vesicles and refringent particles observed in human blood represent non-living membrane vesicles and protein aggregates derived from blood. The phenomena observed during live-blood analysis are therefore consistent with time-dependent decay of cells and body fluids during incubation ex vivo.

Layered double hydroxides as an effective additive in polymer gelled electrolyte based dye-sensitized solar cells.

Layered double hydroxides (LDH), a class of anionic clay materials, were developed as an effective additive for polymer gelled electrolytes for use in dye-sensitized solar cells (DSSC). Carbonate and chloride intercalated Zn-Al LDHs, ZnAl-CO3 LDH, and ZnAl-Cl LDH were prepared with coprecipitation methods. The addition of the two LDHs significantly improved, in terms of power conversion efficiency (PCE), over the plain poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) gelled electrolyte and competed favorably with the liquid electrolyte based DSSCs, 8.13% for the liquid electrolyte, 7.48% for the plain PVDF-HFP gelled electrolyte, 8.11% for the ZnAl-CO3 LDH/PVDF-HFP gelled electrolyte, and 8.00% for the ZnAl-Cl LDH/PVDF-HFP gelled electrolyte based DSSCs. The good performance in PCEs achieved by the LDH-loaded DSSCs came mainly from the significant boost in open circuit voltages (Voc), from 0.74 V for both the liquid electrolyte and PVDF-HFP gelled electrolyte based DSSCs to 0.79 V for both the ZnAl-CO3 LDH/PVDF-HFP and ZnAl-Cl LDH/PVDF-HFP gelled electrolyte based DSSCs. The boost in Voc was contributed mainly by the positive shift in redox potential of the redox couple, I(-)/I3(-), as revealed from cyclic voltammetry analyses. As for the long-term stability, PCE retention rates of 96 and 99% after 504 h were achieved by the ZnAl-CO3 LDH/PVDF-HFP and ZnAl-Cl LDH/PVDF-HFP gelled electrolyte based DSSCs, respectively, appreciably better than 92% achieved by the liquid electrolyte based one after 480 h.

[Change of substance P in portal vein during rectoanal inhibitory reflex].

OBJECTIVE: To investigate the change pattern of substance P (SP) in the portal vein during the rectoanal inhibitory reflex (RAIR), and its physiologic significance; the influence of external splanchnic nerve of rectum and anal to the RAIR. METHODS: The rats were divided into seven groups, among them there were six groups, which were first divided into two big groups according to whether the external splanchnic nerve to the rectum and anal were cut off, one is no cut-off external splanchnic nerve group, the other is cut-off external splanchnic nerve group. Each group were further divided, according to the distance of the balloon-sac on Foley's tube in the rectum away from anal verge, into 2, 4, 6 centimeter groups; A control group with Foley's tube put into the rectum, but the balloon-sac on Foley's tube did not pumped up with water. Measure and compare the value and change of SP in the portal vein during the RAIR. RESULTS: The comparison of SP in portal vein, among the 2, 4 centimeter groups with cut-off external splanchnic nerve, all groups with intact external splanchnic nerve supply and control group, had no statistic difference (P>0.05). The comparison between the 6 centimeter group with intact external splanchnic nerve group and the 2, 4 centimeter groups with cut-off external splanchnic nerve, P<0.01, the statistic difference was significant. The comparison between 6 centimeter group of intact and cut-off external splanchnic nerve, P<0.01, the difference was significant. CONCLUSION: The reason for the stimulation on upper rectum dose not induce the RAIR is related with this stimulation result in the release of SP, the exciting mediator to internal sphincter. The external splanchnic nerve supply of rectum and anal canal have influence on the change of SP of the portal vein during RAIR.