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 acid-fast and non-acid-fast bacteria. Mycobacterium is an acid-fast bacterium …
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 …
Gynoecium, carpel or pistil primarily comprises three structures, namely stigma, style and ovary. It accounts for the flower’s female reproductive part that carries the female gametes or ovules within an ovary. Towards the gynoecium base, the pedicle or thalamus provides support to the female reproductive part and the other parts as well. An ovary is …
DNA generally exists in three common types (represented as B, A and Z forms). Besides B, A and Z forms, DNA may rarely exist as A, C and E forms. Therefore, DNA possesses six different forms that are either in a left or right-handed fashion, under appropriate physiological conditions. Inspite of the above six forms, DNA …
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, …
Actinomycetes belong to the group of prokaryotic, gram-positive bacteria those are having a filamentous structure. Its filamentous structure resembles the fungal mycelium, which consists of a highly dense and filamentous network. Due to the filamentous structure of actinomycetes, it is also termed as thread or ray bacteria. The cell wall and the internal structure of …