Nanovibrational Stimulation of <i>Escherichia coli </i>Mitigates Surface Adhesion by Altering Cell Membrane Potential

Mechanical forces shape living matter from the macro- to the microscale as both eukaryotic and prokaryotic cells are force wielders and sensors. However, whereas such forces have been used to control mechanically dependent behaviors in mammalian cells, we lack the same level of understanding in bacteria. Surface adhesion, the initial stages of biofilm formation and surface biofouling, is a mechanically dependent process, which makes it an ideal target for mechano-control. In this study, we employed nanometer surface vibrations to mechanically stimulate bacteria and investigate their effect on adhesion. We discovered that vibrational stimulation at the nanoscale consistently reduces surface adhesion by altering cell membrane potential. Our findings identify a link between bacteria electrophysiology and surface adhesion and provide evidence that the nanometric mechanical "tickling" of bacteria can inhibit surface adhesion.</p

Nanovibrational Stimulation of <i>Escherichia coli </i>Mitigates Surface Adhesion by Altering Cell Membrane Potential

Mechanical forces shape living matter from the macro- to the microscale as both eukaryotic and prokaryotic cells are force wielders and sensors. However, whereas such forces have been used to control mechanically dependent behaviors in mammalian cells, we lack the same level of understanding in bacteria. Surface adhesion, the initial stages of biofilm formation and surface biofouling, is a mechanically dependent process, which makes it an ideal target for mechano-control. In this study, we employed nanometer surface vibrations to mechanically stimulate bacteria and investigate their effect on adhesion. We discovered that vibrational stimulation at the nanoscale consistently reduces surface adhesion by altering cell membrane potential. Our findings identify a link between bacteria electrophysiology and surface adhesion and provide evidence that the nanometric mechanical "tickling" of bacteria can inhibit surface adhesion.</p

Biofilm and swarming emergent behaviours controlled through the aid of biophysical understanding and tools

Bacteria can organise themselves into communities in the forms of biofilms and swarms. Through chemical and physical interactions between cells, these communities exhibit emergent properties that individual cells alone do not have. While bacterial communities have been mainly studied in the context of biochemistry and molecular biology, recent years have seen rapid advancements in the biophysical understanding of emergent phenomena through physical interactions in biofilms and swarms. Moreover, new technologies to control bacterial emergent behaviours by physical means are emerging in synthetic biology. Such technologies are particularly promising for developing engineered living materials (ELM) and devices and controlling contamination and biofouling. In this minireview, we overview recent studies unveiling physical and mechanical cues that trigger and affect swarming and biofilm development. In particular, we focus on cell shape, motion and density as the key parameters for mechanical cell–cell interactions within a community. We then showcase recent studies that use physical stimuli for patterning bacterial communities, altering collective behaviours and preventing biofilm formation. Finally, we discuss the future potential extension of biophysical and bioengineering research on microbial communities through computational modelling and deeper investigation of mechano-electrophysiological coupling

Interleukin 28 polymorphisms and hepatocellular carcinoma development after direct acting antiviral therapy for chronihepatitis c

Background &amp; Aims: Cirrhotic patients with hepatitis C virus (HCV) infection remain at risk of developing hepatocellular carcinoma (HCC) even after the sustained virologic response (SVR). We aimed to evaluate whether the IL28 (rs12979860) single nucleotide polymorphism (SNP) may constitute a predisposing genetic factor and to identify the SVR patients at risk of HCC. Methods: Two hundred patients undergoing DAAs treatment for chronic hepatitis C with advanced fibrosis (F3-F4) were consecutively enrolled. Besides normal routine laboratory testing for HCV, patients’ sera were evaluated also for retinol, retinol-binding protein 4 and the following SNPs: PNPLA3 (rs738409), TM6SF2 (rs58542926), MBOAT7 (rs641738), IL28B (rs12979860), TIMP-1 (rs4898), TIMP-2 (rs8179090), NF-kB promoter (rs28362491). Statistical analyses were conducted using Stata/SE 14.2 statistical software (Stata Corp, College Station, TX). Results: Almost all patients (197/200) obtained SVR24. Seventeen patients had a previous history of treated HCC before DAAs. Six patients developed HCC recurrence and five patients developed de novo HCC after a mean period of 18 months since EOT. All these patients had SVR. A significant association between IL28B – TT genotype and HCC development after DAAs therapy was observed (OR 4.728, CI 95% 1.222 – 18.297, p=0.024). Conclusion: IL28B rs12979860 polymorphism was significantly associated with HCC development after DAAs. Assessment of this SNP may better identify patients at risk of developing HCC after treatment. Further prospective studies are required to confirm these hypotheses

An engineered anti-idiotypic antibody-derived killer peptide (KP) early activates swine inflammatory monocytes, CD3+CD16+ natural killer T cells and CD4+CD8α+ double positive CD8β+ cytotoxic T lymphocytes associated with TNF-α and IFN-γ secretion

This study evaluated the early modulation of the phenotype and cytokine secretion in swine immune cells treated with an engineered killer peptide (KP) based on an anti-idiotypic antibody functionally mimicking a yeast killer toxin. The influence of KP on specific immunity was investigated using porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) as ex vivo antigens. Peripheral blood mononuclear cells (PBMC) from healthy pigs were stimulated with KP and with a scramble peptide for 20 min, 1, 4 and 20 h or kept unstimulated. The cells were analyzed using flow cytometry and ELISA. The same time-periods were used for KP pre-incubation/co-incubation to determine the effect on virus-recalled interferon-gamma (IFN-γ) secreting cell (SC) frequencies and single cell IFN-γ productivity using ELISPOT. KP induced an early dose-dependent shift to pro-inflammatory CD172α+CD14+high monocytes and an increase of CD3+CD16+ natural killer (NK) T cells. KP triggered CD8α and CD8β expression on classical CD4−CD8αβ+ cytotoxic T lymphocytes (CTL) and double positive (DP) CD4+CD8α+ Th memory cells (CD4+CD8α+low CD8β+low). A fraction of DP cells also expressed high levels of CD8α. The two identified DP CD4+CD8α+high CD8β+low/+high CTL subsets were associated with tumor necrosis factor alpha (TNF-α) and IFN-γ secretion. KP markedly boosted the reactivity and cross-reactivity of PRRSV type-1- and PCV2b-specific IFN-γ SC. The results indicate the efficacy of KP in stimulating Th1-biased immunomodulation and support studies of KP as an immunomodulator or vaccine adjuvant

Effect of gastro-esophageal reflux symptoms on the risk of Barrett's esophagus: A systematic review and meta-analysis

Background and Aim Gastro-esophageal reflux (GER) is the main predisposing factor for Barrett's esophagus (BE). A more precise estimate of the association of GER symptoms with the risk of BE would be important to prioritize endoscopic screening. We conducted a systematic review and meta-analysis to examine this issue. Methods MEDLINE, EMBASE, and EMBASE Classic were searched to identify cross-sectional studies that reported the prevalence of BE based on presence of GER symptoms. The prevalence of BE was compared according to presence or absence of GER symptoms using an odds ratio (OR), with a 95% confidence interval (CI). Specificity and sensitivity of GER symptoms for predicting BE was calculated. Results Of 10,463 citations evaluated, 19 studies reported the prevalence of BE in 43,017 subjects. The pooled OR among individuals with weekly GER symptoms compared with those without was 1.67 (95% CI 1.30-2.15) for endoscopically suspected BE, and 2.42 (95% CI 1.59-3.68) for histologically confirmed BE. No significant association was found between weekly GER symptoms and the presence of short segment BE (OR 1.30; 95% CI 0.86-1.97), whereas a strong association was present with long segment BE, with an OR of 6.30 (95% CI 2.26-17.61). Conclusions Gastro-esophageal reflux symptoms are associated with an increased odds of BE, with a further increase when weekly symptoms are present. Overall, GER symptoms showed low sensitivity and specificity for predicting BE; however, a strong association was found between weekly GER symptoms and long segment BE, but not short segment BE, suggesting that it may be worth considering screening individuals with weekly GER symptoms to rule out long segment BE

Epigenetic regulation of Delta-Like1 controls Notch1 activation in gastric cancer

The Notch signaling pathway drives proliferation, differentiation, apoptosis, cell fate, and maintenance of stem cells in several tissues. Aberrant activation of Notch signaling has been described in several tumours and in gastric cancer (GC), activated Notch1 has been associated with de-differentiation of lineage-committed stomach cells into stem progenitors and GC progression. However, the specific role of the Notch1 ligand (DLL1) in GC has not yet been elucidated. To assess the role of DLL1 in GC cancer, the expression of Notch1 and its ligands DLL1 and Jagged1, was analyzed in 8 gastric cancer cell lines (KATOIII, SNU601, SNU719, AGS, SNU16, MKN1, MKN45, TMK1). DLL1 expression was absent in KATOIII, SNU601, SNU719 and AGS. The lack of DLL1 expression in these cells was associated with promoter hypermethylation and 5-aza-2’deoxycitidine caused up-regulation of DLL1. The increase in DLL1 expression was associated with activation of Notch1 signalling, with an increase in cleaved Notch1 intracellular domain (NICD) and Hes1, and down-regulation in Hath1. Concordantly, Notch1 signalling was activated with the overexpression of DLL1. Moreover, Notch1 signalling together with DLL1 methylation were evaluated in samples from 52 GC patients and 21 healthy control as well as in INS-GAS mice infected with H. pylori and randomly treated with eradication therapy. In GC patients, we found a correlation between DLL1 and Hes1 expression, while DLL1 methylation and Hath1 expression were associated with the diffuse and mixed type of gastric cancer. Finally, none of the samples from INS-GAS mice infected with H. pylori, a model of intestinal-type gastric tumorigenesis, showed promoter methylation of DLL1. This study shows that Notch1 activity in gastric cancer is controlled by the epigenetic silencing of the ligand DLL1, and that Notch1 inhibition is associated with the diffuse type of gastric cancer