Three-dimensional tracking of the ciliate Tetrahymena reveals the mechanism of ciliary stroke-driven helical swimming

Helical swimming in free-space is a common behavior among microorganisms, such as ciliates that are covered with thousands hair-like motile cilia, and is thought to be essential for cells to orient directly to an external stimulus. However, a direct quantification of their three-dimensional (3D) helical trajectories has not been reported, in part due to difficulty in tracking 3D swimming behavior of ciliates, especially Tetrahymena with a small, transparent cell body. Here, we conducted 3D tracking of fluorescent microbeads within a cell to directly visualize the helical swimming exhibited by Tetrahymena. Our technique showed that Tetrahymena swims along a right-handed helical path with right-handed rolling of its cell body. Using the Tetrahymena cell permeabilized with detergent treatment, we also observed that influx of Ca2+ into cilia changed the 3D-trajectory patterns of Tetrahymena swimming, indicating that the beating pattern of cilia is the determining factor in its swimming behavior.

Janus Hydrogel Microbeads for Glucose Sensing with pH Calibration

We present fluorescent Janus hydrogel microbeads for continuous glucose sensing with pH calibration. The Janus hydrogel microbeads, that consist of fluorescent glucose and pH sensors, were fabricated with a UV-assisted centrifugal microfluidic device. The microbead can calibrate the pH values of its surroundings and enables accurate measurements of glucose within various pH conditions. As a proof of concept, we succeeded in obtaining the accurate value of glucose concentration in a body-fluid-like sample solution. We believe that our fluorescent microbeads, with pH calibration capability, could be applied to fully implantable sensors for continuous glucose monitoring.

Characterization of microplastics and anthropogenic fibers in surface waters of the North Saskatchewan River, Alberta, Canada

Microplastics are globally ubiquitous contaminants, but quantitative data on their presence in freshwater environments are sparse. This study investigates the occurrence, composition, and spatial trends of microplastic contamination in the North Saskatchewan River flowing through Edmonton, Alberta, the fifth largest city in Canada. Surface water samples were collected from seven sites throughout the city, upstream and downstream of the city, and near potential point sources (i.e., a wastewater treatment plant). Samples were spiked with fluorescent microbeads as internal standards and extracted by wet peroxide oxidation and density floatation. Microplastics were found in all samples, ranging in concentration from 4.6 to 88.3 particles·m−3 (mean = 26.2 ± 18.4 particles·m−3). Fibers were the dominant morphology recovered, and most were of anthropogenic origin and chemically identified as dyed cotton or polyester by Raman microspectroscopy. The majority of fragments were identified as polyethylene or polypropylene. No upstream to downstream differences were found in concentration, size distribution, or morphological composition suggesting nonpoint sources of microplastics to the river. This study represents one of the first investigations into the occurrence of microplastics in the freshwater environment in western Canada and will provide a baseline for future studies.

Plant-derived angiogenin fusion protein’s cytoprotective effect on trabecular meshwork damage induced by Benzalkonium chloride in mice

Background Benzalkonium chloride (BAK), commonly used in glaucoma treatment, is an eye drop preservative with dose-dependent toxicity. Previous studies have observed the multi-functional benefits of angiogenin (ANG) against glaucoma. In our study, we evaluated ANG’s cytoprotective effect on the trabecular meshwork (TM) damage induced by BAK. Additionally, we developed a plant-derived ANG fusion protein and evaluated its effect on TM structure and function. Methods We synthesized plant-derived ANG (ANG-FcK) by fuzing immunoglobulin G’s Fc region and KDEL to conventional recombinant human ANG (Rh-ANG) purified from transgenic tobacco plants. We established a mouse model using BAK to look for degenerative changes in the TM, and to evaluate the protective effects of ANG-FcK and Rh-ANG. Intraocular pressure (IOP) was measured for 4 weeks and ultrastructural changes, deposition of fluorescent microbeads, type I and IV collagen, fibronectin, laminin and α-SMA expression were analyzed after the mice were euthanized. Results TM structural and functional degeneration were induced by 0.1% BAK instillation in mice. ANG co-treatment preserved TM outflow function, which we measured using IOP and a microbead tracer. ANG prevented phenotypic and ultrastructure changes, and that protective effect might be related to the anti-fibrosis mechanism. We observed a similar cytoprotective effect in the BAK-induced degenerative TM mouse model, suggesting that plant-derived ANG-FcK could be a promising glaucoma treatment.

The Platelet-Derived Microparticles Related to the Clinical Phenotype Heterogeneity of Hemophlia a

Keywords: Hemophlia A, Phenotype; Heterogeneity; Flowcytometry ; Mircoparticle Background: The clinical phenotype for hemophlia A are typically recognized sub-clinical, mild, moderate and severe according to the residue FVIII level of the plasma. For recent years, there are evidences indicate that the residue FVIII level is not the only factor relate to the clinical phenotype of patients with severe hemophlia A. Platelets are an important role in hemostasis and platelet-derived microparticles (PMPs) are known to mediate a prothrombotic state in patients, we hypothesized that PMPs contributes to the clinical phenotype heterogeneity of hemophilia A patients. Methods: Thirty-one patients with severe hemophlia A (FVIII:C<1%, age 18-33 yrs, median 23.5 yrs) treated on demand were enrolled in this study, including 10 patients with mild type(FVIII:C<1%, but annualized bleed rates<6) and 21 patients with severe type (FVIII:C<1% and annualized bleed rates≥24). Seventeen healthy male donors were selected as normal controls. We also compared the baseline PMPs counts from eleven patients on demand treatment to that when they had three months prophylactic treatment. Venous blood was anticoagulated with sodium citrate (1:9). Plasma was isolated (1550g for 20 min at RT) and then cell free supernatant was ultracentrifuged (18,000g for 20 min at 20°C). The supernatant plasma samples were measured for baseline PMPs counts, with phycoerythrin (PE)-conjugated monoclonal antibodies CD41, CD42b, CD61, CD62P, and CD63 specific for PMPs derived from platelets respectively. Analyzed by flow cytometry, Forward scatter was set in scale using fluorescent microspheres of 1.0μm and standard fluorescent microbeads (0-1.0μm) in diameter were used to set the microparticle gate. Statistics were performed using independent-samples T test Results: There was a trend toward higher the mean level of PMPs counts in mild type patients compared to severe type (mean ± SD: 2.06±1.33 vs 0.95±0.64, p = 0.02), the PMPs counts of normal individuals was significantly higher than severe type(mean ± SD: 1.06±1.20 v s0.95±0.64, p = 0.02), significantly lower than mild type (mean ± SD: 1.06±1.20 vs 2.06±1.33, p = 0.02). The PMPs counts decreased after 3 months low dose (10 iu/kg, 2-3/w) prophylacticlly treatment (mean ± SD: 6.50±0.51 vs 0.45±0.50, p = 0.00). Conclusion/Discussion: Platelet-derived Microparticles (PMPs) are generated in response to platelet activation, our observations demonstrate that the PMPs counts differs in patients of severe hemophlia A, the mean lever of PMPs in mild clinical phenotype patients was higher than the severe type, prophylacticlly treated patients has a lower PMPs lever, PMPs is likely to play a role in clincal phenotype heterogeneity of sever hemophilia A. Disclosures No relevant conflicts of interest to declare.