Toxins are produced by pathogenic bacteria. Endotoxins are considered heat liable proteins that are specifically produced or secreted by certain species of gram bacteria. Exotoxins are lipopolysaccharide complex type of protein that is liberated after the death of bacteria. Both of these toxins vary from each other in chemical nature and other aspects as well. Endotoxins are consist of lipids and secreted by some specific species of bacteria. Exotoxins, on the other side, are consist of proteins.
Endotoxins vs Exotoxins
The main difference between endotoxins and exotoxins is that endotoxins are a type of toxin released by gram bacteria, and it is present in the out sheath area of the cell wall. It is also called lipopolysaccharides. On the contrary, exotoxins are released with organism development. This type of toxin is contagious and may cause damage to various parts of the body. They are more toxic as compared to endotoxins. Even a single molecule can affect a large number of host cells.
Endotoxins are secreted or released from the outer area of the cell wall of bacteria after its death. These toxins are comprised of lipoglycan complex and are also called lipopolysaccharides. Endotoxins are moderately toxic and are not very active. Hence a large volume or amount of toxin is required to cause disease.
Exotoxins are the toxins that are produced or developed inside pathogenic bacteria as an integral part of their metabolism and growth. These are majorly produced by gram-negative bacteria and gram-positive bacteria. Exotoxins are highly toxic as a single molecule of toxin can act or affect a large number of host cells and cause harm to various parts or organs of the body.
Comparison Table Between Endotoxins and Exotoxins
| Parameters of Comparison | Endotoxins | Exotoxins |
| What is it? | Endotoxins are released by an integral part of the cell wall of the bacteria and are mostly produced by gram-negative bacteria | Exotoxins are developed or produced inside pathogenic bacteria as an integral part of their metabolism and growth |
| Toxicity | These toxins are moderately toxic | These toxins are highly toxic |
| Neutralization | Endotoxins cannot be neutralized by antibodies | Exotoxins can be neutralized by antibodies |
| Detection | These types of toxins can be detected by limulus lysate assay | These toxins can be detected or located by many tests like precipitation, neutralization, etc. |
| Disease Caused | Disease caused by endotoxins is sepsis by gram-negative rods, meningococcemia, etc.. | Diseases caused by exotoxins are diphtheria, botulism, tetanus, etc. |
What is Endotoxins?
Endotoxins are released by an integral part of the cell wall of the bacteria and are mostly produced by gram-negative bacteria. These toxins are also called lipopolysaccharides. Endotoxins are mostly composed of three components including, O negative antigen, Lipid A, and core oligosaccharide.
Endotoxins are moderately toxic and not very active on their substrate. Its molecular weight is nearly 50-1000KDa. Catalase, lgG/IgA proteases, and catalyse are the enzymes present in these toxins. These toxins are secreted after the death of the bacteria. Endotoxins have low potency, and hence a large amount of toxin is required to affect a part or cause disease.
What is Exotoxins?
Exotoxins are developed or produced inside pathogenic bacteria as an integral part of their metabolism and growth. These toxins are produced by gram-negative bacteria and gram-positive bacteria. The molecular weight of these toxins is 10KDa. Exotoxins are composed of basically two subunits, A and B. Subunit A is nearly to have catalytic activity, while on the other side, subunit B is required for binding with the correct or appropriate cell receptors.
Nuclease, hyaluronidase, certain protease, collagenase, phospholipase A, neuraminidase are the enzymes present in exotoxins. These toxins are highly toxic. A single molecule can affect or act on a large number of host cells. These can be neutralized effectively by antibodies.
Main Differences Between Endotoxins and Exotoxins
Conclusion
Microbes play a vital role and are found everywhere in the living organism. Toxins are categorized into two types, endotoxins and exotoxins. These toxins are produced by some specific bacteria, and they lead to various diseases and infections. Enzymes and toxins are important in the pathogenicity of the pathogenic bacteria and may damage cells and can also trigger or damage the immune response.
References
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