Botulism disease is caused by a bacterial agent, Clostridium botulinum, that produces an exotoxin. Clostridium botulinum causes bacterial food poisoning or intoxication as it releases exotoxin. Exotoxin acts as a neurotoxin, which disables the normal functioning of the nervous system. Thus, an exotoxin produced by Clostridium botulinum is called botulinum neurotoxin, which blocks the synthesis of the …
Acid-fast staining was originally pioneered by a scientist named Paul Ehrlich in the year 1882. Later, it was modified by Ziehl and Neelson in 1883. Thus, acid-fast staining is also called Ziehl Neelson staining. It is a type of differential staining method used to distinguish between the acid-fast and non-acid fast bacteria. Mycobacterium is an …
Photoreactivation repair is the DNA repair system, which corrects the damage (caused by UV-C and UV-B radiations) with the aid of photolyase enzyme under the exposure of visible light. The first evidence for the photoreactivation was given by the two scientists, namely Hausser and Von Oehmcke, in 1933. Hausser and Von Oehmcke reversed the darkened …
Excision repair is one of the types of DNA repair systems. It is an enzymatic process, which follows a cut, copy and paste mechanism. A cutting mechanism involves removing a damaged part or unusual bases by specific enzymes like glycosylases and helicases. Then, a copying mechanism uses DNA polymerase. DNAP-I uses the template DNA to …
The life cycle of adenovirus has different stages like attachment, internalization, uncoating, replication, biosynthesis, assembly and release of viral progenies. After lysing the host cell, they infect new cells and cause infections either for the short term or long term. Adenovirus mainly causes four kinds of infection like a productive, abortive, latent and oncogenic infection. …
Adenovirus is a type of DNA virus, which appears medium-sized, non-enveloped and double-stranded. Adenovirus named after its isolation from the human adenoid tissue. It was first introduced by a scientist named Rowe, who cultured and isolated adenovirus via plasma tissue culturing. This group of virus can infect human, animals and birds. Adenovirus can cause various …
A complement fixation test is a serological assay used to detect antibody or antigen in the patient’s serum by using a complement. A complement participates in the immunological reaction and particularly binds with the antibody. Without antibodies, a complement may lyse the erythrocytes. A complement fixation test is a very complex process, which requires five …
Spoilage of fish is a process of deterioration in the quality of fish, which changes its appearance, odour and taste. The breakdown of biomolecules like proteins, amino acids and fats in the fish are the factors responsible for fish spoilage. Thus, a fish can be spoiled by either chemical or biological degradation. In chemical degradation, …
Endospore staining is a type of special staining method, which makes use of differential staining procedure to highlight the presence or absence of endospores. For the staining of endospores, the first article was published by Dorner in the year 1922. Later, the Dorner method of staining endospores has been modified by two scientists, Schaeffar and …
Capsule staining is one of the staining methods, which creates contrast in the microscopic image either by staining bacterial cells and background or staining the capsule only. Therefore, capsule staining can be done by two methods, namely positive and negative staining methods. Positive staining method either stain a capsule only or stain both the capsule …