Cell-Wall-Targeting Antibiotics Cause Lag-Phase Bacteria to Form Surface-Mediated Filaments Promoting the Formation of Biofilms and Aggregates.

Antibiotics are known to promote bacterial formation of enhanced biofilms, the mechanism of which is not well understood. Here, using biolayer interferometry, we have shown that bacterial cultures containing antibiotics that target cell walls cause biomass deposition on surfaces over time with a linear profile rather than the Langmuir-like profiles exhibited by bacterial adherence in the absence of antibiotics. We observed about three times the initial rate and 12 times the final biomass deposition on surfaces for cultures containing carbenicillin than without. Unexpectedly, in the presence of antibiotics, the rate of biomass deposition inversely correlated with bacterial densities from different stages of a culture. Detailed studies revealed that carbenicillin caused faster growth of filaments that were seeded on surfaces from young bacteria (from lag phase) than those from high-density fast-growing bacteria, with rates of filament elongation of about 0.58 and 0.13 µm min-1 , respectively. With surfaces that do not support bacterial adherence, few filaments were observed even in solution. These filaments aggregated in solution and formed increased amounts of biofilms on surfaces. These results reveal the lifestyle of antibiotic-induced filamentous bacteria, as well as one way in which the antibiotics promote biofilm formation.

HaloTag display enables quantitative single-particle characterisation and functionalisation of engineered extracellular vesicles.

Extracellular vesicles (EVs) play key roles in diverse biological processes, transport biomolecules between cells and have been engineered for therapeutic applications. A useful EV bioengineering strategy is to express engineered proteins on the EV surface to confer targeting, bioactivity and other properties. Measuring how incorporation varies across a population of EVs is important for characterising such materials and understanding their function, yet it remains challenging to quantitatively characterise the absolute number of engineered proteins incorporated at single-EV resolution. To address these needs, we developed a HaloTag-based characterisation platform in which dyes or other synthetic species can be covalently and stoichiometrically attached to engineered proteins on the EV surface. To evaluate this system, we employed several orthogonal quantification methods, including flow cytometry and fluorescence microscopy, and found that HaloTag-mediated quantification is generally robust across EV analysis methods. We compared HaloTag-labelling to antibody-labelling of EVs using single vesicle flow cytometry, enabling us to measure the substantial degree to which antibody labelling can underestimate proteins present on an EV. Finally, we demonstrate the use of HaloTag to compare between protein designs for EV bioengineering. Overall, the HaloTag system is a useful EV characterisation tool which complements and expands existing methods.

HaloTag display enables quantitative single-particle characterization and functionalization of engineered extracellular vesicles.

Extracellular vesicles (EVs) play key roles in diverse biological processes, transport biomolecules between cells, and have been engineered for therapeutic applications. A useful EV bioengineering strategy is to express engineered proteins on the EV surface to confer targeting, bioactivity, and other properties. Measuring how incorporation varies across a population of EVs is important for characterizing such materials and understanding their function, yet it remains challenging to quantitatively characterize the absolute number of engineered proteins incorporated at single-EV resolution. To address these needs, we developed a HaloTag-based characterization platform in which dyes or other synthetic species can be covalently and stoichiometrically attached to engineered proteins on the EV surface. To evaluate this system, we employed several orthogonal quantification methods, including flow cytometry and fluorescence microscopy, and found that HaloTag-mediated quantification is generally robust across EV analysis methods. We compared HaloTag-labeling to antibody-labeling of EVs using single vesicle flow cytometry, enabling us to quantify the substantial degree to which antibody labeling can underestimate the absolute number of proteins present on an EV. Finally, we demonstrate use of HaloTag to compare between protein designs for EV bioengineering. Overall, the HaloTag system is a useful EV characterization tool which complements and expands existing methods.

The impacts of pretreatment circulating eosinophils and basophils on prognosis of stage â -â ¢ colorectal cancer.

AIM: The effects of circulating eosinophils and basophils on cancer survival are unclear. Here, we aimed to explore the impacts of eosinophils and basophils on prognosis of stage I-III colorectal cancer (CRC) patients. METHODS: From February 2003 to March 2013, 569 stage I-III CRC patients were enrolled in this retrospective study. The associations between pretreatment circulating eosinophils, basophils and CRC overall survival (OS), disease-free survival (DFS) were investigated. Moreover, the prognostic value of combined eosinophils/basophils and neutrophil to lymphocyte ratio (NLR)/platelet to lymphocyte ratio (PLR) was investigated. RESULTS: Kaplan-Meier methods showed the associations of eosinophils < 0.095 × 109 /L and shorter OS (P < 0.0001), eosinophils < 0.055 × 109 /L and shorter DFS (P < 0.0001), basophils < 0.015 × 109 /L and shorter OS (P = 0.001), basophils < 0.015 × 109 /L and shorter DFS (P = 0.005). Cox regression model showed that eosinophils < 0.095 × 109 /L (hazard ratio [HR], 1.723; 95% confidence intervals [CI] = 1.177-2.523) and basophils < 0.015 × 109 /L (HR, 1.714; 95% CI = 1.152-2.548) were independent prognostic factors for OS, and eosinophils < 0.055 × 109 /L (HR, 2.309; 95% CI = 1.587-3.361) and basophils < 0.015 × 109 /L (HR, 1.397; 95% CI = 1.003-1.945) were independent prognostic factors for DFS, respectively. The combined eosinophil-PLR (HR, 2.611; 95% CI = 1.328-5.130) and basophil-PLR (HR, 2.520; 95% CI = 1.240-5.123) were the independent prognostic factors for OS. The combined eosinophil-NLR (HR, 2.770; 95% CI = 1.528-5.019) and eosinophil-PLR (HR, 4.788; 95% CI = 2.458-9.329) were the independent prognostic factors for DFS. CONCLUSION: Pretreatment circulating eosinophils < 0.095 × 109 /L/0.055 × 109 /L and circulating basophils < 0.015 × 109 /L have significant impacts on prognosis of stage I-III CRC patients.

[Association between serotonin transporter promoter gene polymorphism and clinicopathological factors and effect of the polymorphism on the prognosis of colorectal cancer patients].

OBJECTIVE: To examine the association between the genotype (LL, LS and SS) of serotonin transporter promoter gene polymorphism(5-HTTLPR) and clinicopathological factors, and to investigate the effect of 5-HTTLPR on the prognosis of colorectal cancer patients. METHODS: Data of peripheral blood samples of 161 colorectal cancer patients at the Second Affiliated Hospital of Guangzhou Medical University from October 2009 to January 2014 were collected retrospectively. The genotyping of 5-HTTLPR was determined by PCR and agarose gel electrophoresis. Coincidence Chi-square test was used to examine the 5-HTTLPR genotype with Hardy-Weinberg law. Chi-square test and Cox multifactor model were used to analyze the association of 5-HTTLPR genotype with clinicopathology and prognosis. All the patients were informed and agreed to participate in the study. This study was approved by the Hospital Ethics Committee (2015056). RESULTS: Of 161 colorectal cancer patients, 89 were male and 72 were female; the median age was 64 (25-85) years; 86 (53.5%) cases were colon cancer and 75 (46.5%) were rectal cancer. Genotype was LL in 12 cases, LS in 59 cases and SS in 90 cases, which complied with the law of Hardy-Weinberg genetic balance (χ²=0.288, P=0.592). Univariate analysis showed that 5-HTTLPR gene polymorphism was only associated with lymph node metastasis [lymph node metastasis rate: LL and LS genotype 21.1% (15/71);SS genotype 40.0% (36/90), χ²= 6.532, P=0.011]. The 3-year and 5-year overall survival rates of whole patients were 71% and 63% respectively. Multivariate analysis revealed that the SS genotype was an independent risk factor affecting the overall survival of colorectal cancer patients(HR=1.933, 95%CI:1.090-3.428, P=0.024). CONCLUSION: Among genotypes of 5-HTTLPR gene, colorectal cancer patients with SS genotype have higher risk of lymph node metastasis and poorer prognosis.

The impact of chemotherapy-associated hemoglobin on prognosis of colorectal cancer patients receiving adjuvant chemotherapy.

BACKGROUND AND OBJECTIVE: The association of chemotherapy-associated hemoglobin and survival of colorectal cancer (CRC) receiving adjuvant chemotherapy is uncertain. We sought to explore the prognostic value of chemotherapy-associated hemoglobin in CRC receiving adjuvant chemotherapy and the best cut point affecting prognosis. METHODS: Three hundred and twenty stage II and III CRC patients receiving adjuvant FOLFOX chemotherapy from March 2003 to March 2012 were enrolled. The associations between chemotherapy-associated hemoglobin (the absolute levels of post-chemotherapy) or chemotherapy-associated hemoglobin change (change between the pre- and post-chemotherapy hemoglobins) and disease free survival (DFS) or overall survival (OS) of CRC, and the best cut point were investigated. RESULTS: Log rank test showed the best cut points for chemotherapy-associated hemoglobin and chemotherapy-associated hemoglobin change were respectively 90 g/L, 30 g/L. Cox regression model showed chemotherapy-associated hemoglobin < 90 g/L was the independent prognostic factor for DFS (HR, 2.221; 95% CI = 1.157-4.262), OS (HR, 2.058; 95% CI = 1.009-4.197), respectively, but no association of chemotherapy-associated hemoglobin change ⩾ 30g/L and DFS (HR, 2.063; 95% CI = 0.929-4.583), OS (HR, 1.386; 95% CI = 0.553-3.471) was found. CONCLUSIONS: Chemotherapy-associated hemoglobin < 90 g/L has a significant prognostic value in CRC receiving adjuvant chemotherapy, which is a significant biomarker in the individualized management and may suggest the simple indication for the treatment of anemia in adjuvant chemotherapy in CRC.