Interferons (INF): Definition, Antiviral Properties, Functions, Classification and Clinical Significance

Functions Interferon

(INF: Definition, Antiviral Properties, Classification and Clinical Significance)

Interferons are Glycoproteins with Antiviral Properties

Interferons or INFs are low molecular weight glyco-proteins produced by certain eukaryotic cells in response to viral infections. They are cytokines with indirect or non-specific antiviral activities. Interferons stimulate the production of antiviral proteins in the cells which inhibit the synthesis of viral RNA and proteins. Interferons cannot directly inhibit the viral entry into the host cell. However, they can inhibit the replication of viral gene and the assembly of viral particles and thereby they limit the viral infection.

Interferons also regulate the growth, differentiation and functions of different types of immune cells in animals. Several classes of interferons are recognized in eukaryotes such as INFα, INFβ and INFγ. INFα and INFβ are produced by virus infected fibroblasts. Virus infected leukocytes, antigen stimulated T cells and natural killer cells can produce INFγ.

Interferon Production is Triggered by Viral Infection

The synthesis and release of interferons form a cell is induced by the viral particles. The intact viral particles and even the presence of double stranded viral RNA (dsRNA) in the cell can evoke the production of interferons. Specific interferons are recognized by receptors present on the plasma membrane. Once a cell receives the stimuli, the interferon proteins are synthesized and they are released out of the cell. Since they are secreted to the exterior of the cells, they can bind to its plasma membrane receptors. The secreted interferon molecules then bound to the ganglioside receptors on the plasma membrane of another cell (nearby or located far away from the secretion).

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Biotechnology Lecture Notes

Solid State Fermentation Technology: Examples, Advantages and Disadvantages


Solid State Fermentation (SSF)
(Solid State Fermentation: Technology, Advantages and Disadvantages)

What is Solid State Fermentation (SSF)?

In Solid State Fermentation, also called Solid Substrate Fermentation or SSF, the fermentation substrate or media will be in the solid state. Here the microorganisms are grown on a solid substratum in the absence or near absence of free water. The moisture content of the substratum in SSF is usually maintained below 15%. The solid state fermentation is most commonly carried out for the production of fermented food products such as bread, fermented fish, meat, yogurt, cheese and pickles. The microbial fermentation increases the nutrient content and flavor of food products. It also increases the digestibility of foods. The cultivation of edible mushrooms on a suitable substratum is also a solid state fermentation process.

Pleurotus djamor

Mushroom Cultivation (wikipedia)

Substrates / Media in Solid State Fermentation


The substrates commonly used in SSF are usually very complex, heterogeneous and are insoluble in water. These substrates include cereals grains, wheat bran, lingo-cellulosic materials such as wood shavings, sawdust, molasses etc. In most of the cases, the substrate or the raw materials were undergone through a pre-treatment such as soaking, boiling in water, mechanical pre-treatment or chemical treatment. These pre-treatments increase the bioavailability of nutrients for the microbes to act on them.

Instrumentation and Growth Kinetics in Solid State Fermentation

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Molecular Biology Tutorials

Philadelphia Chromosome and Oncogenic BCR ABL Gene Translocation in CML

Philadelphia Translocation

Philadelphia Chromosome (PH)
(Philadelphia Translocation, PH and Chronic Myeloid Leukemia – CML)

Translocation is a Structural Aberration of Chromosome

Translocation is a type of structural aberration of the chromosome where a segment of chromosome gets translocated to another chromosome. There may be two types of translocation based on the nature of the exchange. They are:

(1). Homologous Translocation

(2). Heterologous Translocation

In homologous translocation, the exchange of chromosomal segments occurs between the homologous chromosomes. In heterologous translocation, the chromosomal segments are exchanged between non-homologous chromosomes. The heterologous translocation in most of the cases will be a reciprocal translocation (exchange of segments between chromosomes).

Translocation causes ‘Position Effect’

The translocation of chromosomes leads to a phenomenon in molecular genetics called the ‘Position Effect’. The position effect is the change in the expression pattern of a gene due to its current position in the chromosome. For example, a normally active gene may be converted to an inactive gene when it is translocated into a new position or vice versa.

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Biostatistics Study Materials

Graphical Representation of Data PPT (Power Point Presentation)

Biometric PPT

Graphical Representation of Data PPT
(Line Diagram, Bar Diagram, Histogram, Frequency Curve, Ogive and Pie Chart)

What is graphical representation? Importance of Graphical Representation, Advantages of Graphical Representation, Disadvantages of Graphical Representation, Things to remember when constructing a Graph, Different types of graphs / charts: Line Diagram, Bar diagram, Simple Vertical Bar Diagram, Subdivided Bar Diagram, Multiple Bar Diagram, Percentage Bar Diagram, Histogram, Frequency Polygon, Frequency Curve, Ogive, Less Than Ogive, Greater Than Ogive, Calculating Median from Ogive, Pie Chart, Relative Frequency and Pie Diagram.

Learn more: Lecture Note in Graphical Representation of Data Part 1, Part 2

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Biostatistics Study Materials

Graphical Representation of Data (Frequency Polygon, Frequency Curve, Ogive and Pie Diagram)

Graphs for Data Representation

Graphical Representation of Data: Part 2
(Data Representation Methods: Frequency Polygon, Frequency Curve, Ogive and Pie Chart)

This post is the continuation of the Previous Post (Graphical Representation of Data Part 1).

(3). Frequency Polygon

Ø  The Frequency Polygon is a curve representing a frequency distribution.

Ø  In frequency polygon, the mid values of each class are first obtained.

Ø  In a graph paper, the frequency of each class is plotted against the mid-value of class (on the X axis).

Ø  Then these points are then joined by a straight line.

Ø  This straight line is extended in both directions to meet on the X axis.

Ø  The first point is joined to the lower limit of the first class and the last point is joined to the upper limit of last class. Thus, the frequency polygon is a closed graph.

Ø  The graph now obtained is called Frequency polygon.

Example: Construct a Frequency Polygon using the following data


data for frequency polygon

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