It is a particular abnormal, pathological condition that affects part or all of an organism. The cell wall of a grampositive bacterium is composed of a heteropolymer of protein and sugar called peptidoglycan. A tissue rich in elastic fibers or other elasticstaining material. Chemical theories it is generally true that acid dyes stain basic elements.
The gram stain is a staining procedure used to not only make bacterial cells more visible under the microscope, but also to differentiate cell types based on the cell wall composition. Several factors control specificity, selectivity and visibility of the end product in any procedure using dyes, fluorochromes, inorganic reagents or histochemical. Modified bismarck brown staining for demonstration of soft tissue mast cells pdf. Theory and practice of histological techniques, 6th edition. Developed from the antigenantibody binding reaction, immunohistochemistry can be considered as a method that visualize distribution and localization of specific antigen or cellular components in separated tissues, or. Staining a stain is any colouring organic compound that combined with another substance imparts a colour to that substance. Five categories of silver stains can be defined by the physicochemical procedures involved. Immunohistochemistry ihc is a method for detecting antigens or haptens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. This was developed in 1884 by a danish bacteriologist, hans christian gram.
Gram stain the previous lab introduced simple staining techniques that enable microbiologists to observe the morphological characteristics of bacteria. Gel staining chemicals, premade gel or gel chemicals, buffers, etc. Jan 08, 2020 the gram staining technique is the most important and widely used microbiological differential staining technique. The second test which was performed following the gram staining was the oxygen tolerance test.
Theories of disease epidemiology online microbiology notes. Christian gram in 1884, and categorizes bacteria according to their gram character gram positive or gram negative. Doc principles of staining mohammad ehtisham academia. This is a brand new edition of the leading reference work on. The differential and cytological staining techniques discussed in this chapter help to differentiate between acid fast and non. Fat stains are effective because the stain is more soluble in fat than in 70% alcohol. Bancrofts theory and practice of histological techniques. Gram staining technique is the widely used differential staining technique in bacteriology. Learn vocabulary, terms, and more with flashcards, games, and other study tools. When viewed with the microscope the bacterial cells, and perhaps their spores, appear light against the dark surrounding background. Stains and dyes are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes. Both aptamerbased 1 fluorescent staining and 2 ihc staining of clinical tissue samples could be automated in the microfluidic system in only 23 hr 4050% faster than conventional approaches. Theories of staining techniques staining bacteria with different dyes via staining techniques, allows in distinguishing the microorganism from its backgrounds.
A brief history of microscopy, theory of operation, key parts of a typical microscope for transmitted light, kohler illumination, the condenser. Haematoxylin is a mordanted dye that can stain many different elements in tissue depending on the mordant used. An introduction to the theory and practice of light microscopy. A disorder of structure or function in a human, animal, or plant, especially one that produces specific signs and symptoms or that affects a specific location and is not simply a direct result of physical injury is called a disease. In this technique the differential stains applied on the. Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Papanicolaou stain pap stain protocol ihc world, llc. Stain uptake is often due to dyetissue or reagenttissue affinities. With coverage of the full range of histological techniques used in medical laboratories and pathology departments, it provides a strong foundation in all aspects of histological technology. Although simple stains are useful, they do not reveal details about the bacteria other than morphology and arrangement. The simple stain can be used as a quick and easy way to determine cell shape, size and arrangements of bacteria. Stains and dyes are frequently used in histology the study of tissue under the microscope and in the medical fields of histopathology, hematology, and cytopathology that focus on the study and diagnoses disease at a microscopic level. Division of radiooncology, deutsches krebsforschungszentrum, 69120 heidelberg, germany. To study and gain expertise on differential and cytological staining techniques.
Tooth staining discoloration due to tetracycline is influenced by dose, length of treatment or exposure, stage of tooth mineralization or calcification and degree of activity of the mineralization process. Theory of staining techniques essay 985 words cram. In our analysis of polarizationsensitive gratings we have employed several coupled wave theories, each with a different set of. The mechanism of staining the case for the physical theories. It is held that adsorption is the principal factor in color retention. Any basic dye such as methylene blue, safranin, or crystal violet can be used to color the bacterial cells. Theories of staining there are numerous theories attempting to explain staining.
Mechanisms and theory new staining techniques continue to be introduced, and older ones continue to be used and. Theories of staining biological staining structural components. They are based on the physical and chemical reactions of the cell to the staining reagents. The first stainings were tried by a van leeuwenhoek apparently in the years 17141719 and by r vieussens about 1684 studying their objects with alcoholic saffron dyes lewis ft, 1942.
Gram staining is the common, important, and most used differential staining techniques in microbiology, which was introduced by danish bacteriologist hans christian gram in 1884. Differential and cytological staining techniques theory. There are many theories, but none are completely satisfactory. Stains may be used to define biological tissues highlighting. The application of the chemical, solution and adsorption theories to dyeing and staining processes is outlined briefly. The gram staining technique differentiates the mixed culture cells into two terms as grampositive bacteria and gramnegative bacteria. Differential staining is a technique that helps to characterize the microorganisms depending on the difference in the physical and chemical nature of the microorganism. Immunohistochemistry ihc is a wideused biological technique that combines anatomy, physiology, immunology and biochemistry. Simple staining implies the use of only a single stain, which is usually sufficient to reveal the morphological features of most microbial cells, including relative size, shape, and characteristic arrangements for groups of cells. Gram staining method, the most important procedure in microbiology, was developed by danish physician hans christian gram in 1884. For brightfield microscopy, negative staining is typically performed using a black ink fluid such as nigrosin and india ink. This test differentiate the bacteria into gram positive and gram negative bacteria, which helps in the classification and differentiations of microorganisms. Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image.
Supporters of vital theories think that the ascent of sap is under the control of vital activities in the stem. The yellowish discoloration caused due to the use of tetracycline is intrinsic or permanent and can vary from yellow or gray to brown. Oct 15, 2009 some staining techniques such as gram staining, endospore stain and capsule stain are some of the theories of stains used in bacteriology today. Flood slide with crystal or gentian violet 60 seconds. Theory and practice of histological techniques 5th ed. Four theories have been proposed to explain the possible mechanism of this side effect. Theories of staining, effects of fixation, dyes, dye chemistry, tissues, and troubleshooting. Personality theories sigmund freud for jews, especially ones as famous as freud. Abstractthe special stains that utilize silver include various staining procedures that are based on very different principles.
Unlike with other tetracyclines, minocycline causes staining during and after the complete formation and eruption of teeth. Theory and practice of histological techniques, 6th. The text uses clear and consistent subheadings, featuring an attractive color scheme and generously sized font that facilitates the reading of detailed. Theories of staining physical solubility adsorption chemical solventsolvent. The most widely used staining procedure in microbiology is the gram stain, discovered by the danish scientist and physician hans christian joachim gram in 1884. The gram staining technique differentiates the mixed culture cells into two terms as gram. To obtain additional information, various specialized differential staining procedures have been developed. Both the techniques allow the observation of cell morphology, or shape, but differential staining usually provides more information about the characteristics of the cell wall thickness. Two such theories are common but they are not very convincing. Theory and practice of silver staining in histopathology. True to its name, the simple stain is a very simple staining procedure involving single solution of stain. We do this by examining some of the theories relating to change and exploring the different types of change. Also, these staining procedures help in determining properties of an unknown culture. Gram staining is still the cornerstone of bacterial identification and taxonomic division.
Electrophoresis basic principles history of electrophoresis types of electrophoresis gel electrophoresis sample types equipment applications basics and theory of. Make a thin film of the material on a clean glass slide, using a sterile loop or swab for viscous specimens. Most of the staining solutions corresponds normally to the specifications given in h. But only a limited number of positions were available, and there were others ahead of him. Also, helps in studying different internal structures such as vacuoles, cell walls and spores in details seeley and others 1991. The most prominent current theories are as follows. In addition this stain also allows determination of cell morphology, size, and arrangement. Tooth stainingdiscoloration due to tetracycline is influenced by dose, length of treatment or exposure, stage of tooth mineralization or calcification and degree of activity of the mineralization process. Cell wall of gram positive bacteria are 40 times thicker than those of gram negative cells, hence they are thought to help retain the dyeiodine complex. The following points highlight the top three staining methods used for colouring the biological materials. Bancrofts theory and practice of histological techniques 7th edition pdf author kim s suvarna mbbs bsc frcp frcpath file size 51. Not long afterward, he died of the cancer of the mouth and jaw that he had suffered from for the last 20 years of his life. Earlier staining theories developed as if different. Papanicolaou stain also papanicolaous stain and pap stain is a multichromatic staining histological technique developed by george papanikolaou, the father of cytopathology.
Chapter 8 answers the question how do histological stains work. The previous lab introduced simple staining techniques that enable microbiologists to observe the morphological characteristics of bacteria. Gram staining is a differential staining technique that differentiates bacteria into two groups. This is a property by which a large body attracts to itself minute particles from a surrounding medium. Pap staining is used to differentiate cells in smear preparations of various bodily secretions. The staining times for most simple stains are relatively short, usually from 30 seconds to 2 minutes, depending on the affinity of th e d ye. The differential and cytological staining techniques discussed in this chapter help to differentiate between acid fast and non acid fast cells and to visualize the intracellular constituents of the microbial cells including endospores, capsules, metachromatic granules, and flagella. Gram staining differential stains use two or more stains and allow the cells to be categorized into various groups or types. In spite of his defective method, his name lives on jay hardy, cls, sm ascp jay hardy is the founder and. Histochemical and other staining techniques are outlined in sufficient but succinct detail, with notes on expected staining patterns and suggestions for solving common staining problems. These are argentaffin methods, argyrophil methods, impregnation stains, silver oxidationreduction stains, and metallicmetallic interactions autometallography. For 40 years, bancrofts theory and practice of histological techniques have established itself as the standard reference for histotechnologists and laboratory scientists, as well as histopathologists. The specimen, such as a wet bacterial culture spread on a glass slide, is mixed with the negative stain and allowed to dry. Ihc staining is commonly used in many research and clinical applications.