Hypervirulent Klebsiella pneumoniae induced ventilator-associated pneumonia in mechanically ventilated patients in China

The purpose of this study was to investigate the clinical characteristics of hypervirulent K. pneumoniae (hvKP) induced ventilator-associated pneumonia (VAP) and the microbiological characteristics and epidemiology of the hvKP strains. A retrospective study of 49 mechanically ventilated patients with K. pneumoniae induced VAP was conducted at a university hospital in China from January 2014 to December 2014. Clinical characteristics and K. pneumoniae antimicrobial susceptibility and biofilm formation were analyzed. Genes of capsular serotypes K1, K2, K5, K20, K54 and K57 and virulence factors plasmid rmpA(p-rmpA), iroB, iucA, mrkD, entB, iutA, ybtS, kfu and allS were also evaluated. Multilocus sequence typing (MLST) and random amplified polymorphic DNA (RAPD) analyses were used to study the clonal relationship of the K. pneumoniae strains. Strains possessed p-rmpA and iroB and iucA were defined as hvKP. Of 49 patients, 14 patients (28.6 %) were infected by hvKP. Antimicrobial resistant rate was significantly higher in cKP than that in hvKP. One ST29 K54 extended-spectrum-beta-lactamase (ESBL) producing hvKP strain was detected. The prevalence of K1 and K2 in hvKP was 42.9 % and 21.4 %, respectively. The incidences of K1, K2, K20, p-rmpA, iroB, iucA, iutA, Kfu and alls were significantly higher in hvKP than those in cKP. ST23 was dominant among hvKP strains, and all the ST23 strains had identical RAPD pattern. hvKP has become a common pathogen of VAP in mechanically ventilated patients in China. Clinicians should increase awareness of hvKP induced VAP and enhance epidemiologic surveillance.

Precision Measurement of the Helium Flux in Primary Cosmic Rays of Rigidities 1.9 GV to 3 TV with the Alpha Magnetic Spectrometer on the International Space Station

Knowledge of the precise rigidity dependence of the helium flux is important in understanding the origin, acceleration, and propagation of cosmic rays. A precise measurement of the helium flux in primary cosmic rays with rigidity (momentum/charge) from 1.9 GV to 3 TV based on 50 million events is presented and compared to the proton flux. The detailed variation with rigidity of the helium flux spectral index is presented for the first time. The spectral index progressively hardens at rigidities larger than 100 GV. The rigidity dependence of the helium flux spectral index is similar to that of the proton spectral index though the magnitudes are different. Remarkably, the spectral index of the proton to helium flux ratio increases with rigidity up to 45 GV and then becomes constant; the flux ratio above 45 GV is well described by a single power law.

Acute cholecystitis associated with infection of Enterobacteriaceae from gut microbiota

Acute cholecystitis (AC) is one of the most common surgical diseases. Bacterial infection accounts for 50% to 85% of the disease's onset. Since there is a close relationship between the biliary system and the gut, the aims of this study were to characterize and determine the influence of gut microbiota on AC, to detect the pathogenic microorganism in the biliary system, and to explore the relationship between the gut and bile microbiota of patients with AC. A total of 185 713 high-quality sequence reads were generated from the faecal samples of 15 patients and 13 healthy controls by 16S rRNA gene pyrosequencing. Patients' samples were significantly enriched in Akkermansia, Enterobacter and Escherichia/Shigella group. The healthy controls, however, showed significant enrichment of Clostridiales, Coprococcus, Coprobacillaceae, Paraprevotella, Turicibacter and TM7-3 in their faecal samples. Escherichia coli was the main biliary pathogenic microorganism, among others such as Klebsiella spp., Clostridium perfringens, Citrobacter freundii and Enterobacter cloacae in the bile of the patients. Additionally, the amount of bile endotoxin significantly correlated with the number of Enterobacteriaceae, especially E. coli. Our data indicate that Enterobacteriaceae might play essential role in the pathogenesis and/or progress of AC. This was verified in an in vivo model using a pathogenic E. coli isolated from one of the patients in guinea pigs and observed marked gallbladder inflammation and morphologic changes. This study thus provides insight which could be useful for the prevention, diagnosis and treatment of AC and related diseases by controlling the growth of Enterobacteriaceae to alleviate the infection.

Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station

A precise measurement of the proton flux in primary cosmic rays with rigidity (momentum/charge) from 1 GV to 1.8 TV is presented based on 300 million events. Knowledge of the rigidity dependence of the proton flux is important in understanding the origin, acceleration, and propagation of cosmic rays. We present the detailed variation with rigidity of the flux spectral index for the first time. The spectral index progressively hardens at high rigidities.

Precision Measurement of the (e^{+}+e^{-}) Flux in Primary Cosmic Rays from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station

We present a measurement of the cosmic ray (e^{+}+e^{-}) flux in the range 0.5 GeV to 1 TeV based on the analysis of 10.6 million (e^{+}+e^{-}) events collected by AMS. The statistics and the resolution of AMS provide a precision measurement of the flux. The flux is smooth and reveals new and distinct information. Above 30.2 GeV, the flux can be described by a single power law with a spectral index γ=-3.170±0.008(stat+syst)±0.008(energy scale).

Comparative study on gastrointestinal microbiota of eight fish species with different feeding habits

AIMS

To reveal the effects of fish genotype, feeding habits and serum physiological index on the composition of gastrointestinal microbiota, eight fish species with four different feeding habits were investigated.

METHODS AND RESULTS

The V1 to V3 regions of 16S rRNA gene were analysed by high-throughput sequencing (454 platform) to compare the gut microbiota of different fish species. A total of 551 995 high-quality sequences with an average length of 463 bp were obtained from the 48 samples. No significant difference was observed among the detected sequences obtained from fishes with different feeding habits (One-way anova, F = 1·003, P = 0·400), but the number of OTUs among different feeding habits was significantly different (One-way anova, F = 7·564, P < 0·001). Additionally, significant correlations were detected between the fish genotype and microbial composition (partial Mantel test, all P values = 0·001) in the stomach, foregut and hindgut. Moreover, different core intestinal microbiota was also noticed in the eight fish species with different feeding habits.

CONCLUSIONS

Feeding habits and genotype clearly affected the gastrointestinal microbiota of fish. Moreover, the evolutionary process shaped the serum physiological indexes of fish.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided much important information for developing commercial fish feeds.

Investigating the role of angiogenesis in systemic lupus erythematosus

OBJECTIVE

We aimed to elucidate the roles of six pro-angiogenic factors, namely, basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), placental growth factor (PlGF), hepatocyte growth factor (HGF), transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha), in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

A group of 75 patients with SLE and a control group of 40 healthy volunteers were recruited. Angiogenic factors were tested through enzyme-linked immunosorbent assay (ELISA) measurement. The angiogenic activities of the patients with SLE and the healthy controls were assessed and a correlation analysis of these angiogenic factors was conducted.

RESULTS

A much higher level of angiogenic activity was shown in the serum of patients with SLE than that of the healthy controls, yet no statistically significant difference was found in the angiogenic activities of active SLE and inactive SLE. Serum VEGF level in the active SLE group was significantly higher than that in the control group and the inactive SLE group, and serum HGF level was strongly positively correlated with VEGF in all SLE groups; meanwhile, there was also a statistically significant positive correlation between TNF-alpha and VEGF in all SLE groups. There was a statistically significant positive correlation between serum VEGF level and bFGF level in the active SLE group. There was a slightly negative correlation between serum HGF level and TGF-beta level in the SLE group, but this negativity did not reach the significance level. Likewise, positive correlation was also shown in the serum VEGF level and PlGF level, yet not in bFGF with PlGF.

CONCLUSION

Circulating serum angiogenic cytokines may be disease markers of SLE activity. Anti-angiogenic agents such as thalidomide and endogenous angiogenesis inhibitors such as endostatin are potentially effective and promising therapies in the treatment of SLE.

Electron and positron fluxes in primary cosmic rays measured with the alpha magnetic spectrometer on the international space station

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30  GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

High statistics measurement of the positron fraction in primary cosmic rays of 0.5-500 GeV with the alpha magnetic spectrometer on the international space station

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200  GeV the positron fraction no longer exhibits an increase with energy.

Low-temperature storage and cryopreservation of grapefruit (Citrus paradisi Macfad.) seeds

BACKGROUND

Grapefruit is an economically important fruit worldwide, but our knowledge of its seed biology is rather poor.

OBJECTIVE

The present study aimed to develop techniques for banking and cryopreservation of grapefruit seeds.

MATERIALS AND METHODS

Grapefruit seeds with the exotesta removed were used. Seeds were desiccated to three moisture levels between 5-9 % and stored at 15 degree C, 4 degree C and -20 degree C for up to 24, months to investigate seed lifespan in conventional seed bank. Meanwhile seeds desiccated by silica gel or saturated salt solution and embryonic axes by flash drying were employed to develop cryopreservation protocols.

RESULTS

It was confirmed that grapefruit seeds have some intermediate properties, being able to withstand removal of type II water up to 7 % MC, but sensitive to -20 degree C storage. For cryopreservation, the excised embryonic axes had a wider moisture window between 5 % and 15%, with a maximum past-thaw emergence of 95 %, while seeds survived only with a maximum past-thaw emergence of 50 % or 70 % from a much narrow moisture window.

CONCLUSION

In contrast to previous reports on another type II seed, coffee, we found that citrus seeds desiccated by silica gel had better post-thaw viability than those subjected to equilibrium desiccation with saturated salt solutions. Further investigation is required to elucidate the mechanisms that contribute to variable cryopreservation tolerance.

Prediction and extraction of microRNA2target interactions associated with leukemia

MicroRNAs are small, non-coding RNAs that regulate gene expression by suppressing mRNA translation or inducing mRNA degradation, and have been implicated in a growing number of diseases. To understand microRNAs' function, it is vital to identify microRNA2target interactions. This work explores the prediction and extraction of leukemia-associated microRNA2target interactions, based on text mining. We extracted 371 interactions of microRNA2targets that, from prior knowledge, could be related to leukemia. By measuring similarities between unknown and known targets, the study could also predict some interactions of microRNA2targets. To analyze the prioritized data, the proposed approach identified some microRNA2target interactions, 17 of which were validated by other evidences. The remaining unconfirmed interactions provide a resource for leukemia researchers. Experimental results show the work has promise for predicting and extracting interactions of microRNA2targets related to leukemia.

ChIP-seq analysis of histone H3K9 trimethylation in peripheral blood mononuclear cells of membranous nephropathy patients

Membranous nephropathy (MN), characterized by the presence of diffuse thickening of the glomerular basement membrane and subepithelial in situ immune complex disposition, is the most common cause of idiopathic nephrotic syndrome in adults, with an incidence of 5-10 per million per year. A number of studies have confirmed the relevance of several experimental insights to the pathogenesis of human MN, but the specific biomarkers of MN have not been fully elucidated. As a result, our knowledge of the alterations in histone methylation in MN is unclear. We used chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) to analyze the variations in a methylated histone (H3K9me3) in peripheral blood mononuclear cells from 10 MN patients and 10 healthy subjects. There were 108 genes with significantly different expression in the MN patients compared with the normal controls. In MN patients, significantly increased activity was seen in 75 H3K9me3 genes, and decreased activity was seen in 33, compared with healthy subjects. Five positive genes, DiGeorge syndrome critical region gene 6 (DGCR6), sorting nexin 16 (SNX16), contactin 4 (CNTN4), baculoviral IAP repeat containing 3 (BIRC3), and baculoviral IAP repeat containing 2 (BIRC2), were selected and quantified. There were alterations of H3K9me3 in MN patients. These may be candidates to help explain pathogenesis in MN patients. Such novel findings show that H3K9me3 may be a potential biomarker or promising target for epigenetic-based MN therapies.

Protection against hepatitis E virus infection by naturally acquired and vaccine-induced immunity

Immunity acquired from infection or vaccination protects humans from symptomatic hepatitis E. However, whether the risk of hepatitis E virus (HEV) infection is reduced by the immunity remains unknown. To understand this issue, a cohort with 12 409 participants randomized to receive the hepatitis E vaccine Hecolin(®) or placebo were serologically followed up for 2 years after vaccination. About half (47%) of participants were initially seropositive. A total of 139 infection episodes, evidenced by four-fold or greater rise of anti-HEV level or positive seroconversion, occurred in participants who received three doses of treatment. Risk of infection was highest among the baseline seronegative placebo group participants (2.04%). Pre-existing immunity and vaccine-induced immunity lower the risk significantly, to 0.52% and 0.30%, respectively. In conclusion, both vaccine-induced and naturally acquired immunity can effectively protect against HEV infection.

Protein serine/threonine phosphotase-1 is essential in governing normal development of vertebrate eye

Protein serine/threonine phosphatase-1 (PP-1) is one of the key enzymes responsible for dephosphorylation in vertebrates. Protein dephosphorylation via PP-1 is implicated in many different biological processes including gene expression, cell cycle control, transformation, neuronal transmission, apoptosis, autophage and senescence. However, whether PP-1 directly controls animal development remains to be investigated. Here, we present direct evidence to show that PP-1 plays an essential role in regulating eye development of vertebrates. Using goldfish as a model system, we have shown the following novel results. First, inhibition of PP-1 activity leads to death of a majority of the treated embryos, and the survived embryos displayed severe phenotype in the eye. Second, knockdown of each catalytic subunit of PP-1 with morpholino oligomers leads to partial (PP-lα knockdown) or complete (PP-lβ or PP-lγ knockdown) death of the injected embryos. The survived embryos from PP-1α knockdown displayed clear retardation in lens differentiation. Finally, overexpression of each subunit of PP-1 also causes death of majority of the injected embryos and leads to abnormal development of goldfish eye. Mechanistically, Pax-6 is one of the major downstream targets mediating the effects of PP-1 function since the eye phenotype in Pax-6 knockdown fish is similar to that derived from overexpression of PP-1. Together, our results for the first time provide direct evidence that protein phosphatase-1 plays a key role in governing normal eye formation during goldfish development.

Synergy between Kaposi's sarcoma-associated herpesvirus (KSHV) vIL-6 and HIV-1 Nef protein in promotion of angiogenesis and oncogenesis: role of the AKT signaling pathway

Kaposi's sarcoma-associated herpesvirus (KSHV) is the cause of Kaposi's sarcoma (KS), which is the most common AIDS-associated malignancy. KS is characterized by neovascularization and spindle cell proliferation. The interaction between HIV-1 and KSHV has a central role in promoting the aggressive manifestations of KS in AIDS patients; however, the pathogenesis underlying AIDS-related KS (AIDS-KS) remains unknown. Herein, we examined the potential of HIV-1 negative factor (Nef) to impact KSHV viral interleukin-6 (vIL-6)-induced angiogenesis and tumorigenesis. In vitro experiments showed that exogenous Nef penetrated vIL-6-expressing endothelial cells. Both internalized and ectopic expression of Nef in endothelial cells and fibroblasts synergized with vIL-6 to promote vascular tube formation and cell proliferation. Using a chicken chorioallantoic membrane (CAM) model, we demonstrated that Nef synergistically promotes vIL-6-induced angiogenesis and tumorigenesis. Animal experiments further showed that Nef facilitates vIL-6-induced angiogenesis and tumor formation in athymic nu/nu mice. Mechanistic studies indicated that Nef synergizes with vIL-6 to enhance angiogenesis and tumorigenesis by activating the AKT pathway in the CAM model, as well as nude mice. LY294002, a specific inhibitor of phosphatidylinositol-3-kinase (PI3K), significantly impaired the ability of Nef to promote vIL-6-induced tumorigenesis in an allograft model of nude mice. Our data provide first-line evidence that Nef may contribute to the pathogenesis underlying AIDS-KS in synergy with vIL-6. These novel findings also suggest that targeting the PI3K/AKT signal may be a potentially effective therapeutic approach in AIDS-KS patients.