[Remediation Effects of Different Composite Materials on Cadmium-Contaminated Farmland Soil].

A pot experiment was conducted to study the application effects of three composite materials, namely SC (lime:organic compound fertilizer=2:3), LS (ferrous sulfate:lime=1:1) and LB (ferrous sulfate:biochar in combinations of 1:1, 1:2, 1:3, 1:4 and 1:5), on soil Cd bioavailability, Cd cumulative distribution in different wheat organs, and wheat yield. The results indicated that:① Addition of composite materials all significantly decreased the soil available Cd content by 50.2%-81.8% (SC), 29.4%-48.1% (LS), and 18.7%-42.2% (LB). Composite materials significantly increased soil pH by 1.37-2.28 (SC), 0.41-0.86 (LS), and 0.14-0.17 (LB) units. ② The Cd cumulative distribution in different wheat organs were in the order of root > leaf > stem > glume > grain. The translocation abilities of Cd in different organs were in the order of root > glume > stem and leaf. ③ Compared with the control, 0.67% SC addition and 0.67% LS addition significantly increased the wheat yields by 56.4% and 51.2%; LB addition significantly increased wheat yield by 39.6% to 51.2%. ④ The correlation analysis showed that soil pH was significantly negatively correlated with soil available Cd and Cd contents in different wheat organs. There were significant positive correlations between soil available Cd and Cd contents in different wheat organs, and the correlation coefficients were 0.711 (grain), 0.817 (glume), 0.593 (stem), 0.630 (leaf) and 0.622 (root). Meanwhile, there is also a significant positive correlation between Cd content in different wheat organs. ⑤ Comprehensively, the addition of 0.93% SC increased soil pH by a maximum of 2.28 units, and the soil available cadmium content was decreased by a maximum of 81.8%. Therefore, adding 0.93% SC was the most suitable treatment for repairing and controlling the Cd pollution in farmland soil.

Versatile on-stage microfluidic system for long term cell culture, micromanipulation and time lapse assays.

We report here a versatile on-stage microfluidic cell culture and assay system which is compatible with different microscopes and sensors, can simultaneously perform steps of long term cell culture, high throughput time lapse cell assays/imaging, and cell micromanipulations. With the system, we cultured a variety of cells for different periods of time and monitored their cell morphology, migration and division. We also performed a series non-invasive real time in situ time lapse assays and micromanipulations on different cells. They include: the first time lapse imaging and measurements on the instantaneous variations of morphology, biomechanical properties and the intracellular protein of human red blood cells in responding to pH fluctuation, drug action and electromagnetic radiation; the first continuous time lapse Raman micro-spectroscopy on a CHO cell in different phases of its entire life cycles; the micro-transfection of GFP into B16 cells and the follow up observation of the cell's morphology and expressed GFP fluorescence varying with incubation time and cell generations. The performance of these experiments not only demonstrated the capability of the system, but also proposed a variety of novel methods for obtaining time- and spatially-resolved information about the cellular and molecular heterogeneity and transformation during development or stimulations.

Restoring the youth of aged red blood cells and extending their lifespan in circulation by remodelling membrane sialic acid.

Membrane sialic acid (SA) plays an important role in the survival of red blood cells (RBCs), the age-related reduction in SA content negatively impacts both the structure and function of these cells. We have therefore suggested that remodelling the SA in the membrane of aged cells would help recover cellular functions characteristic of young RBCs. We developed an effective method for the re-sialylation of aged RBCs by which the cells were incubated with SA in the presence of cytidine triphosphate (CTP) and α-2,3-sialytransferase. We found that RBCs could be re-sialylated if they had available SA-binding groups and after the re-sialylation, aged RBCs could restore their membrane SA to the level in young RBCs. Once the membrane SA was restored, the aged RBCs showed recovery of their biophysical and biochemical properties to similar levels as in young RBCs. Their life span in circulation was also extended to twofold. Our findings indicate that remodelling membrane SA not only helps restore the youth of aged RBCs, but also helps recover injured RBCs.

How cell number and cellular properties of blood-banked red blood cells of different cell ages decline during storage.

AIMS: Numerous studies have suggested that transfusion of red blood cells (RBCs) stored over a long period of time may induce harmful effects due to storage-induced lesions. However, the underlying mechanisms responsible for this damage have not been identified. Furthermore, it is unclear why and how up to 30% of long-stored RBCs disappear from the circulation within 24 hours after transfusion. The aim of this study was to determine how the cell number of RBCs of different ages changes during storage and how these cells undergo cumulative structural and functional changes with storage time. METHODS AND RESULTS: We used Percoll centrifugation to fractionate the RBCs in blood bank stored RBC units into different aged sub-populations and then measured the number of intact cells in each sub-population as well the cells' biomechanical and biochemical parameters as functions of the storage period. We found that the RBC units stored for ≤ 14 days could be separated into four fractions: the top or young cell fraction, two middle fractions, and the lower or old fraction. However, after 14 days of storage, the cell number and cellular properties declined rapidly whereby the units stored for 21 days only exhibited the three lower fractions and not the young fraction. The cell number within a unit stored for 21 days decreased by 23% compared to a fresh unit and the cells that were lost had hemolyzed into harmful membrane fragments, microparticles, and free hemoglobin. All remaining cells exhibited cellular properties similar to those of senescent cells. CONCLUSION: In RBC units stored for greater than 14 days, there were fewer intact cells with no healthy cells present, as well as harmful membrane fragments, microparticles, and free hemoglobin. Therefore, transfusion of these stored units would not likely help patients and may induce a series of clinical problems.

The effect of the gene carrier material polyethyleneimine on the structure and function of human red blood cells in vitro.

Human red blood cells (RBCs) have high abundance in blood tissue, usually 40-50% v/v. For the in vivo administered biomedical materials in contact with blood tissue, the RBCs are the major (in most cases, undesired) targets encountered. The interaction of the biomaterials with the RBCs will unavoidably occur, affecting the structure and function of the RBCs and then the whole organism. For the clinical applications of biomaterials, this effect should be clearly elucidated since it may cause acute or chronic harm to the organism. Moreover, the RBC-based experimental results could be extended to other tissue cells to a great extent. In this study, the effect of the branched polyethyleneimines (BPEIs) as a gene carrier on the structure and function of human RBCs was studied by using different molecular weights of the BPEIs. Specifically, the RBC aggregation and lysis induced by the BPEIs were first studied; then, the structural and conformational change of hemoglobin in the presence of the BPEIs was examined by using UV-vis, fluorescence, and circular dichroism spectroscopy. Furthermore, the oxygen-carrying function of the RBCs in the presence of the BPEIs was evaluated by measuring the 2,3-diphosphoglycerate (2,3-DPG) level and oxygen-dissociation curves. The results showed that the BPEIs with certain molecular weights at certain concentrations could cause RBC aggregation and lysis, alter the structure and conformation of hemoglobin, and impair the oxygen-delivery function of the RBCs. These data provide valuable information for the molecular design and clinical applications of the BPEIs and other biomedical materials.