Definitions for quellung reaction
quel·lung re·ac·tion

Princeton's WordNetRate this definition:0.0 / 0 votes

1. quellung, quellung reactionnoun

   the swelling of the capsule surrounding a microorganism after reaction with an antibody; the basis of certain tests for identifying microorganisms

   "pneumococcus quellung"

WikipediaRate this definition:0.0 / 0 votes

1. Quellung reaction

   The quellung reaction, also called the Neufeld reaction, is a biochemical reaction in which antibodies bind to the bacterial capsule of Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis, Bacillus anthracis, Haemophilus influenzae, Escherichia coli, and Salmonella. The antibody reaction allows these species to be visualized under a microscope. If the reaction is positive, the capsule becomes opaque and appears to enlarge. Quellung is the German word for "swelling" and describes the microscopic appearance of pneumococcal or other bacterial capsules after their polysaccharide antigen has combined with a specific antibody. The antibody usually comes from a bit of serum taken from an immunized laboratory animal. As a result of this combination, and precipitation of the large, complex molecule formed, the capsule appears to swell, because of increased surface tension, and its outlines become clearly demarcated. The pneumococcal quellung reaction was first described in 1902 by the scientist Fred Neufeld, and applied only to Streptococcus pneumoniae, both as microscopic capsular swelling and macroscopic agglutination (clumping visible with the naked eye). It was initially an intellectual curiosity more than anything else, and could distinguish only the three pneumococcal serotypes known at that time. However, it acquired an important practical use with the advent of serum therapy to treat certain types of pneumococcal pneumonia in the 1920s because selection of the proper antiserum to treat an individual patient required correct identification of the infecting pneumococcal serotype, and the quellung reaction was the only method available to do this. Dr. Albert Sabin made modifications to Neufeld's technique so that it could be done more rapidly, and other scientists expanded the technique to identify 29 additional serotypes.Application of Neufeld’s discoveries to other important areas of research came when Fred Griffith showed that pneumococci could transfer information to transform one serotype into another. Oswald Avery, Colin MacLeod, and Maclyn McCarty later showed that the transforming factor was deoxyribonucleic acid, or DNA.Serum therapy for infectious diseases was displaced by antibiotics in the 1940s, but identification of specific serotypes remained important as the understanding of the epidemiology of pneumococcal infections still required their identification to determine where different serotypes spread, as well as the variable invasiveness of different serotypes. Understanding the prevalence of various serotypes was also critical to the development of pneumococcal vaccines to prevent invasive infections. The quellung reaction has been used to identify the 93 known capsular serotypes of Streptococcus pneumoniae in diagnostic settings, but in recent years it has been challenged by the latex agglutination method, and further by molecular typing techniques such as the polymerase chain reaction, which detect DNA and therefore target genetic differences between serotypes. Currently, there are 100 known capsular serotypes.

ChatGPTRate this definition:0.0 / 0 votes

1. quellung reaction

   The Quellung reaction, also known as Neufeld reaction, is a biochemical reaction in which certain bacteria or other cells swell up or agglutinate when treated with a specific antiserum. This reaction is commonly used in microbiology to identify certain types of bacteria, particularly Streptococcus pneumoniae. The antiserum used in the reaction contains antibodies that bind to specific antigens on the bacterial cell wall, causing it to swell and become more visible under a microscope.

WikidataRate this definition:5.0 / 1 vote

1. Quellung reaction

   The Quellung reaction is a biochemical reaction in which antibodies bind to the bacterial capsule of Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis, Haemophilus influenzae, and Salmonella. The antibody reaction allows these species to be visualized under a microscope. If the reaction is positive, the capsule becomes opaque and appears to enlarge. Quellung is the German word for "swelling" and describes the microscopic appearance of pneumococcal or other bacterial capsules after their polysaccharide antigen has combined with a specific antibody. The antibody usually comes from a bit of serum taken from an immunized laboratory animal. As a result of this combination, and precipitation of the large, complex molecule formed, the capsule appears to swell, because of increased surface tension, and its outlines become clearly demarcated. The pneumococcal Quellung reaction was first described in 1902 by the scientist Fred Neufeld, both as microscopic capsular swelling and macroscopic agglutination. It has been used to identify the 90 known capsular serotypes of Streptococcus pneumoniae in a diagnostic setting, but in recent years has been challenged by molecular typing techniques which target genetic differences.

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Numerology

1. Chaldean Numerology

   The numerical value of quellung reaction in Chaldean Numerology is: 6

2. Pythagorean Numerology

   The numerical value of quellung reaction in Pythagorean Numerology is: 5

References

1. ^ Princeton's WordNet
   http://wordnetweb.princeton.edu/perl/webwn?s=quellung reaction
2. ^ Wikipedia
   https://en.wikipedia.org/wiki/Quellung_Reaction
3. ^ ChatGPT
   https://chat.openai.com
4. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=quellung reaction