Neutron crystallography reveals mechanisms used by Pseudomonas aeruginosa for host-cell binding

The opportunistic pathogen Pseudomonas aeruginosa, a major cause of nosocomial infections, uses carbohydrate-binding proteins (lectins) as part of its binding to host cells. The fucose-binding lectin, LecB, displays a unique carbohydrate-binding site that incorporates two closely located calcium ions bridging between the ligand and protein, providing specificity and unusually high affinity. Here, we investigate the mechanisms involved in binding based on neutron crystallography studies of a fully deuterated LecB/fucose/calcium complex. The neutron structure, which includes the positions of all the hydrogen atoms, reveals that the high affinity of binding may be related to the occurrence of a low-barrier hydrogen bond induced by the proximity of the two calcium ions, the presence of coordination rings between the sugar, calcium and LecB, and the dynamic behaviour of bridging water molecules at room temperature. These key structural details may assist in the design of anti-adhesive compounds to combat multi-resistance bacterial infections.

THE MEMBRANE DISTILLATION ABILITY TO REMOVE CALCIUM ION FROM DAIRY WASTEWATER

In this research the membranes distillation were used to remove calcium ions from heavy sewers at dairy plants in Iraq. This method is easy to operate, easy to manage and has many economic benefits. A chemical treatment was carried out on it using alum as a coagulant, different tests achieved samples before and after passing MD, according to APHA, AWWA, WEF. The results showed that obtained in water treatment trust that has been manufactured and edited according to the characteristics of the water waste the interests of the dairy capacity of this method to remove the calcium ion to a certain extent it is when the concentration reaches the inside of this ion to 1428.57 mg per liter, where to start the composition of hydroxides of calcium responsible for pain. The optimal working temperature ranges from 20-22 ° C and the flow is around 0.66 kg.m-2.h-1, here was the result of a layer of plaster that led to clogged membrane and folding and was stopped for washing and cleaning.

Microstructure and Thermal Property of Designed Alginate-Based Polymeric Composite Foam Materials Containing Biomimetic Decellularized Elastic Cartilage Microscaffolds

This study presents a designed alginate-based polymeric composite foam material containing decellularized elastic cartilage microscaffolds from porcine elastic cartilage by using supercritical fluid and papain treatment for medical scaffold biomaterials. The microstructure and thermal property of the designed alginate-based polymeric composite foam materials with various controlled ratios of alginate molecules and decellularized elastic cartilage microscaffolds were studied and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential thermal gravimetric analysis (TGA/DTG). The microstructure and thermal property of the composite foam materials were affected by the introduction of decellularized elastic cartilage microscaffolds. The designed alginate-based polymeric composite foam materials containing decellularized elastic cartilage microscaffolds were ionically cross-linked with calcium ions by soaking the polymeric composite foam materials in a solution of calcium chloride. Additional calcium ions further improved the microstructure and thermal stability of the resulting ionic cross-linked alginate-based polymeric composite foam materials. Furthermore, the effect of crosslinking functionality on microstructures and thermal properties of the resulting polymeric composite foam materials were studied to build up useful information for 3D substrates for cultivating and growing cartilage cells and/or cartilage tissue engineering.

Coagulation performance evaluation of alginate as a natural coagulant for the treatment of turbid water

Alginates are quite abundant in nature as they occur both as a structural component in marine brown algae (Phaeophyceae) comprising up to 40% of dry matter and as capsular polysaccharides in soil bacteria. Alginic acid is the only polysaccharide, which naturally contains carboxyl groups in each constituent residue, and possesses various abilities for functional materials. Experiments were carried out for the water of turbidity 300 NTU. Alginate as such doesn't act as a coagulant instead it should be converted to calcium alginate by adding calcium ions. Calcium chloride was used for imparting calcium ions necessary for the reaction. The dosage of calcium was fixed as 50 mg/L, 75 mg/L, 100 mg/L, 150 mg/L, 200 mg/L, and alginate doses between 2 to 10 mg/L. Calcium dosage below 50 mg/L was not sufficient enough for the formation of egg-box structure which is responsible for the coagulation and flocculation process. For the mechanism of charge neutralization to take place effectively, calcium should be added first followed by alginate. pH and conductivity of the sample remain constant before and after the treatment. The dosage of alginate required for the treatment is less so the cost of treatment also will be very less, thus alginate can replace the usage of chemical coagulants like alum.