Morphology analysis of Escherichia coli treated with nonthermal plasma

AIMS

Nonthermal plasma agents (reactive species and charged particles) are generally generated together. Previous studies of nonthermal plasma agents did not investigate the role of a microbial inactivation agent without interference from other agents. Consequently, the exact mechanism underlying their activity remains unclear. The present experiment was conducted to study the mechanism underlying Escherichia coli inactivation by nonthermal plasma.

METHODS AND RESULTS

The mechanism underlying E. coli inactivation by charged particles was studied using pure argon plasma. Results showed that cell wall damage owing to strong electrostatic forces did not occur during direct current (DC) plasma treatment with Ar or N₂ . Next, the inactivation effects of excited N2∗, N2+, ozone, OH radicals, and nitric oxide were investigated using pure nitrogen plasma and air plasma. Morphological changes and cell rupture of E. coli were observed after 5 min of treatment with nonthermal plasma in air, but not with argon and nitrogen plasma treatments.

CONCLUSIONS

Our data demonstrate that reactive oxygen species play an essential role in the inactivation of E. coli.

SIGNIFICANCE AND IMPACT OF THE STUDY

A clear understanding of the mechanisms underlying nonthermal plasma's inactivation of micro-organism is essential for the practical applications of nonthermal plasma techniques.

[A cohort study on association between the first trimester phthalates exposure and fasting blood glucose level in the third trimester]

Objective: To examine the association between the phthalate exposure in the first trimester and fasting blood glucose level or gestational diabetes mellitus (GDM) in the third trimester in pregnant women. Methods: A total of 3 474 pregnant women, receiving their prenatal examination in Ma' anshan Maternal and Child Health-Care Hospital of Anhui province, were selected from May 2013 to September 2014. Questionnaires were used to collect the information about their socio-demographic characteristics, clinical characteristics and GDM diagnostic results in the first, second and third trimesters. Urine samples and fasting venous blood samples were collected. Concentrations of 7 kinds of phthalate metabolites in urine samples were detected by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS), and multiple linear regression model was used for statistical analyses. Logistic regression analysis on the risk of the first trimester phthalate exposure for GDM in the third trimester was conducted. Results: The prevalence of GDM in this study was 12.8%, monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEHHP) exposure levels were positively correlated with the fasting blood glucose level in the third trimester (P<0.05), but mono-(2-ethylhexyl) phthalate (MEHP) and mono-(2-ethyl-5-hydroxylhexyl) phthalate (MEOHP) exposure levels were negatively correlated with the fasting blood glucose level in the third trimester (P<0.05). Stratified analysis showed a positive correlation between MEHHP exposure and the third trimester fasting blood glucose level in both normal group and GDM group. However, MMP, MEP, MBP, MBzP, MEHP and MEOHP exposure levels had influences on the third trimester fasting blood glucose level in normal group but not in GDM group. MMP and MBP exposure might increase the risk of GDM, but MEOHP exposure might reduce the risk of GDM. Conclusion: The phthalate exposure in the first trimester might be associated with the fasting blood glucose level in the third trimester, MMP, MEP, MBP, MBzP and MEHHP concentrations were positively associated with the third trimester blood glucose level, MEHP and MEOHP concentrations were negatively associated with the third trimester blood glucose level. Moreover, the effects of different kinds of phthalates might be different.

[The value of urinary neutrophil gelatinase-associated lipocalin for early diagnosis of contrast-induced nephropathy]

Objective: To explore the value of urinary neutrophil gelatinase-associated lipocalin (NGAL) for early diagnosis of contrast-induced nephropathy (CIN) in patients who underwent percutaneous coronary angiography (CAG) or percutaneous coronary intervention (PCI). Methods: From May 2015 to January 2016, 506 consecutive patients who underwent CAG or PCI in our hospital were enrolled in this prospective study. Patients were divided into CIN group (n=47) and non-CIN group (n=459). Clinical and interventional data were compared between the two groups. Spearman ranking correlation coefficient was used to define the relation between NGAL and CIN, and multivariable logistic regression analysis was performed to identif independent predictors of CIN. Receiver-operator characteristic (ROC) curve was generated, and area under the curve (AUC) was calculated and sensitivity and specificity for CIN diagnosis were analyzed. Results: (1) Basic clinical and interventional data including age, incidence of diabetes, hypertension and chronic heart failure, level of systolic blood pressure, serum creatine before procedure, use of isotonic contrast agent, contrast volume, Mehran score, operation time, treatment number of coronary artery, hydration and medication were all similar between two groups (all P>0.05). (2) Urinary NAGL level at 24 and 48 h after procedure, serum creatinine (Scr) level at 48 h after procedure, and ΔNGAL_{24-0 h} were significantly higher in CIN group than in non-CIN group (all P<0.01), but the differences of urinary NGAL level before procedure, Scr level 24 h after procedure, and ΔNGAL_{48-24 h} were similar between two groups (all P>0.05). (3)The positive correlation was found by Spearman ranking correlation between ΔNGAL_{24-0 h} and CIN (r=0.478, P<0.001). (4) Multivariable logistic regression analysis showed that estimated glomerular filtration rate(OR=1.020, 95%CI 1.005-1.035, P=0.007) and ΔNGAL_{24-0 h} (OR=1.020, 95%CI 1.014-1.027, P<0.001) were the independent predictors of CIN.(5) ROC curve showed that the AUC of NGAL with the cutoff value 4.65 was 0.899(0.854, 0.944)for diagnosis of CIN (sensitivity 93.6%, and specificity 0.944). Conclusion: The rise of urinary NGAL level at 24 and 48 hours after CAG or PCI is suggestive of CIN and could be used as a reliable parameter for the early diagnose of CIN.

Quantum Critical Scaling in the Disordered Itinerant Ferromagnet UCo_{1-x}Fe_{x}Ge

The Belitz-Kirkpatrick-Vojta (BKV) theory shows in excellent agreement with experiment that ferromagnetic quantum phase transitions (QPTs) in clean metals are generally first order due to the coupling of the magnetization to electronic soft modes, in contrast to the classical analogue that is an archetypical second-order phase transition. For disordered metals the BKV theory predicts that the second-order nature of the QPT is restored because the electronic soft modes change their nature from ballistic to diffusive. Our low-temperature magnetization study identifies the ferromagnetic QPT in the disordered metal UCo_{1-x}Fe_{x}Ge as the first clear example that exhibits the associated critical exponents predicted by the BKV theory.

[Previous medical or surgical abortions and subsequent risk of preterm birth: a birth cohort study]

Objective: To understand the association between medical abortion (MA) or surgical abortion (SA) and the risk of preterm birth (PTB) in subsequent pregnancy. Methods: The prospective cohort study was conducted in Ma'anshan, Anhui province. The information about demographic characteristics and previous MA or SA of 3 474 pregnant women were collected before 14 gestational weeks. Logistic regression analysis was conducted to compare the rates of preterm birth based on the history of previous MA or SA, and 3 256 live births were included in the analysis. Results: The PTB rate and spontaneous preterm birth (sPTB) rate were 4.12% (n=134) and 2.49% (n=81) respectively. Previous MA was associated with an increased risk of total PTB (RR=2.00, 95%CI: 1.04-3.85 for one MA and RR=3.58, 95%CI: 1.04-12.30 for two or more MAs) and sPTB (RR=2.51, 95% CI: 1.23-5.15). The risk of PTB in women with one SA (RR=0.67, 95%CI: 0.42-1.01) or more SA (RR=0.97, 95%CI: 0.51-1.85) did not differ significantly compared with the women with no history of SA. Conclusion: This study suggests that medical abortion could increase the risk of PTB or sPTB.

Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

[Intrahepatic cholestasis of pregnancy and fetal outcomes: a prospective birth cohort study]

OBJECTIVE

To evaluate the relations between the second and third trimesters intrahepatic cholestasis of pregnancy (ICP) and the fetal outcomes, in order to provide medical advice for early detection and intervention on ICP.

METHODS

A prospective cohort study was conducted in Ma' anshan, Anhui, China (Ma'anshan Birth Cohort, MABC). Pregnant women within 14 weeks of gestation were consecutively recruited when standards were met. Anthropometrics were collected in early pregnancy. Maternal serum total bile acid level (TBA) was collected in the second and third trimesters, and women were viewed as cases if the results were accorded with clinical diagnosis. Logistic regressions were conducted to examine the associations of the second and third trimester ICP, and fetal outcomes.

RESULTS

A total of 2 978 pregnant women were included in this study. The rate of ICP was 6.5% (n=196), and the rates of the second and third trimesters were 1.4% (n=43) and 5.1% (n=153) respectively. After controlling for potential confounders, we found that ICP from both the second and third trimesters could increase the risks of preterm birth, low birth weight (LBW), fetal distress and meconium-stained amniotic fluid.OR values (95% CI) were 6.42 (2.59-15.93) and 3.73 (2.07-6.72) for preterm birth while 6.52 (2.19-19.45) and 4.90 (2.43-9.90) for LBW, 2.91 (1.27-6.67) and 1.88 (1.11-3.19) for fetal distress and 2.34 (1.19-4.61) and 1.66 (1.11-2.48) for meconium-stained amniotic fluids, respectively. The risk of adverse fetal outcomes caused by the second trimester ICP appeared significantly higher than the third trimester ICP.

CONCLUSION

ICP from the second and third trimesters significantly increased the risk of adverse fetal outcomes, suggesting that clinicians should put more attention to the second trimester ICP. Both early detection and intervention were of great importance in reducing the adverse fetal outcomes.

Toxicity study of ochratoxin A using HEK293 and HepG2 cell lines based on microRNA profiling

Ochratoxin A (OTA) induced DNA damage, cytotoxicity, and apoptosis in mammalian cell lines. Micro RNAs (miRNAs) are involved in physiological and developmental processes and contribute to cancer development and progression. In our study, high-throughput miRNA profiling and Kyoto Encyclopedia of Genes and Genomes analysis were applied to comparatively study the toxicity of OTA in HEK293 cells and HepG2 cells treated with 25 μM OTA for 24 h. In these two cells, the same changing miRNAs were mostly related to signal transduction pathways, whereas the different changing miRNAs were mostly related to human cancer pathways. DGCR8, Dicer1, and Drosha were significantly suppressed in HEK293 cells, indicating an impairment of miRNA biogenesis. The damage seemed more extensive in HEK293 cells. Cell models and in vivo models were also compared. Many miRNAs in vitro were markedly different from those in vivo; however, OTA toxicity was observed both in vitro and in vivo. The classification of deregulated pathways is similar. The biogenesis of miRNA was impaired in both lines. In conclusion, deregulated miRNAs in vitro are mostly related to human cancer and signal transduction pathways. The deregulated pathways in vivo are similar to those in vitro.

MiR-204 regulates HMGA2 expression and inhibits cell proliferation in human thyroid cancer

BACKGROUND

Analysis using publicly available algorithms has found that high mobility group AT-hook 2 (HMGA2), a key transcriptional regulatory factor, is a potential target of microRNA-204 (miR-204). Some studies have shown that both miR-204 and HMGA2 are associated with cancer development.

OBJECTIVE

We examined the possible relationship between miR-204 and HMGA2 in the development of thyroid cancer.

METHODS

We assessed miR-204 expression in thyroid cancer specimens and cell lines using real-time polymerase chain reaction (PCR). Luciferase reporter assay was used to confirm the target associations. The effect of miR-204 on cell proliferation was confirmed with tetrazolium and colony formation assays. Gene and protein expression were examined using real-time PCR and western blotting, respectively.

RESULTS

MiR-204 was downregulated in the thyroid cancer specimens and cell lines, and targeted the 3^\prime untranslated region of HMGA2 directly. MiR-204 overexpression decreased cyclin D1 and Ki67 expression and increased P21 expression, which subsequently inhibited thyroid cancer cell proliferation.

CONCLUSIONS

Our findings suggest that miR-204 plays a protective role by inhibiting thyroid cancer cell proliferation, and may identify new targets for anti-cancer treatment.

Bax/Bak activation in the absence of Bid, Bim, Puma, and p53

How BH3-only proteins activate Bax/Bak, the two gateway proteins of the mitochondria-dependent apoptotic pathway, remains incompletely understood. Although all pro-apoptotic BH3-only proteins are known to bind/neutralize the anti-apoptotic Bcl-2 proteins, the three most potent ones, Bid (tBid), Bim, and Puma, possess an additional activity of directly activating Bax/Bak in vitro. This latter activity has been proposed to be responsible for triggering Bax/Bak activation following apoptotic stimulation. To test this hypothesis, we generated Bid^−/−Bim^−/−Puma^−/− (TKO), TKO/Bax^−/−/Bak^−/− (PentaKO), and PentaKO/Mcl-1^−/− (HexaKO) HCT116 cells through gene editing. Surprisingly, although the TKO cells were resistant to several apoptotic stimuli, robust apoptosis was induced upon the simultaneous inactivation of Bcl-xL and Mcl-1, two anti-apoptotic Bcl-2 proteins known to suppress Bax/Bak activation and activity. Importantly, such apoptotic activity was completely abolished in the PentaKO cells. In addition, ABT-737, a BH3 mimetic that inhibits Bcl-xL/Bcl-w/Bcl-2, induced Bax activation in HexaKO cells reconstituted with endogenous level of GFP-Bax. Further, by generating TKO/p53^−/− (QKO) cells, we demonstrated that p53, a tumor suppressor postulated to directly activate Bax, is not required for Bid/Bim/Puma-independent Bax/Bak activation. Together, these results strongly suggest that the direct activation activities of Bid (tBid), Bim, Puma, and p53 are not essential for activating Bax/Bak once the anti-apoptotic Bcl-2 proteins are neutralized.