China 
Africa 
Explore chapters and articles related to this topic
Direct Measurement of Microbial Growth
Published in Maria Csuros, Csaba Csuros, Klara Ver, Microbiological Examination of Water and Wastewater, 2018
Maria Csuros, Csaba Csuros, Klara Ver
Gram stain is a general test for characterization of bacteria and for examination of culture purity. The Gram differentiation is based upon the application of a series of four chemical reagents: primary dye, mordant, decolorizer, and counterstain. Primary dye—The purpose of the primary dye, crystal violet, is to impart a purple or blue color to all organisms regardless of their designated Gram reaction.Mordant—The crystal violet treatment followed by the application of Gram’s iodine, which acts as a mordant by enhancing the union between the crystal violet dye and its substrate by forming a complex.Decolorizer—The decolorizing solution of acetone-alcohol extracts the complex from certain cells more readily than from others.Counterstain—A safranin counterstain is applied in order to see those organisms previously decolorized by the removal of the complex.
Methods for Evaluating Articular Cartilage Quality
Published in Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi, Articular Cartilage, 2017
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi
Dyes commonly used for staining cartilage glycosaminoglycans take advantage of the negative charge of molecules, and these include Safranin O, toluidine blue, and Alcian blue (Figure 5.17). Safranin O is a red to orange stain, often used with Fast Green (a neutral dye) as a counterstain. Articular cartilage should first be protonated in an acidic solution before dye binding occurs. Toluidine blue is a metachromatic dye that changes from blue to pink-purple when the sulfated groups of a glycosaminoglycan molecule bring several dye molecules close together. This color change is only visible under aqueous conditions, and dried toluidine blue complexes will appear blue. Toluidine blue has been used in cartilage histology with aqueous mounts to distinguish sulfated glycosaminoglycans from other anionic species.
Microbiological drinking water parameters
Published in Frank R. Spellman, The Drinking Water Handbook, 2017
The Gram staining procedure was developed in the 1880s by Hans Christian Gram, a Danish bacteriologist. Gram discovered that microbes could be distinguished from surrounding tissue and observed that some bacterial cells exhibit an unusual resistance to decolorization. He used this observation as the basis for a differential staining technique. Gram differentiation is based on the application of a series of four chemical reagents: primary stain, mordant, decolorizer, and counterstain. The purpose of the primary stain, crystal violet, is to impart a blue or purple color to all organisms regardless of their Gram reaction. This is followed by the application of Gram’s iodine, which acts as a mordant (fixer) that enhances the union between the crystal violet stain and its substrate by forming a complex. The decolorizing solution of 95% ethanol extracts the complex from certain cells more readily than others. In the final step, a counterstain (safranin) is applied to reveal organisms previously decolorized by removal of the complex. Those organisms retaining the complex are Gram positive (blue or purple), whereas those losing the complex are Gram negative (red or pink).
Curcumin-loaded nanofilm generating avascular niche to stabilize in vivo ectopic chondrogenesis of BMSC
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Renzhong Cai, Yu Zhang, Jun Li, Xu Wu
PGA is a commonly used biomaterial for cartilage TE. Here, after being mixed with PLA, the unwoven PGA fibers (Figure 1a) were compressed to form a cylindrical scaffold with a porous structure (Figure 1b). The third passage BMSCs (Figure 1c) (50 million/mL concentration) were evenly seeded onto the PGA scaffold (Figure 1d), where the cell suspension quickly permeated the PGA sponge to form a BMSC-PGA construct (Figure 1d). It was noted that after 4 weeks of chondrogenic culture, the BMSC-PGA construct had developed to form a smooth ivory-white, cartilage-like tissue (Figure 1e). Histological evaluations that were conducted using the safranin-O and immunohistochemical collagen II staining procedures indicated that the above cartilage-like tissue displayed general cartilage lacunae and cartilage-specific ECM, along with rich glycosaminoglycan (GAG) and type II collagen depositions (Figure 1f-h). After analyzing the above results, it was concluded that the BEC tissue was successfully engineered in vitro using the chondrogenic cultivation of the BMSC-PGA construct.
Preparation of hybrid meniscal constructs using hydrogels and acellular matrices
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Gizem Zihna, Bengisu Topuz, Gülçin Günal, Halil Murat Aydin
Hematoxylin & Eosin (H&E) and DAPI staining were used to confirm the removal of cell nuclei and the integrity of ECM. Posterior regions of meniscus tissues were fixed in 10% (v/v) formalin and subsequently dehydrated by graded series of ethanol and xylene. Then, tissues were embedded in paraffin blocks and sectioned at 5-micron thickness via microtome. The cross-sections were stained with H&E and DAPI. Moreover, Masson’s trichrome staining was performed to observe collagen fibers in native and decellularized tissues. Proteoglycans were visualized with Safranin-O/Fast Green staining. All staining was imaged with a light microscope (Leica, Germany).
Adsorption of Safranin-O dye by copper oxide nanoparticles synthesized from Punica granatum leaf extract
Published in Environmental Technology, 2022
Taynara Basso Vidovix, Heloise Beatriz Quesada, Rosângela Bergamasco, Marcelo Fernandes Vieira, Angélica Marquetotti Salcedo Vieira
Safranin-O (SO) is a dye used in pharmaceutical and biochemical industries in the histology and cytology sectors. It is commonly used for staining gram-negative bacteria and for detecting cartilage, mucin, and mast cell granules [3]. Moreover, it is applied less frequently in food products such as flavouring and colouring of candies and cookies, as well as in the process of colouring and treatment of tannins, cotton, fibres, wool, silk, leather, and paper [4]. In addition to the impact caused by its colour, SO may provoke adverse effects to human health such as eye irritation and burning, dermatitis, and respiratory allergies [5].