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Sunday, September 13, 2009

Pichia as Protein Expression System

Pichia is a methylotrophic yeast which is widely used to express heterologous proteins using recombinant DNA technology.

Pichia pastoris (P.pastoris) is owned and licensed by Research corporation Technologies (RCT).

Pichia pastoris is a methylotrophic yeast, capable of metabolizing methanol as its sole carbon source. The first step in the metabolism of methanol is the oxidation of methanol to formaldehyde using molecular oxygen by the enzyme alcohol oxidase.

In addition to formaldehyde, this reaction generates hydrogen peroxide. To avoid hydrogen peroxide toxicity, methanol metabolism takes place within a specialized cell organelle, called the peroxisome, which sequesters toxic by-products away from the rest of the cell. Alcohol oxidase has a poor affinity for O2, and Pichia pastoris compensates by generating large amounts of the enzyme. The promoter
regulating the production of alcohol oxidase is the one used to drive heterologous protein expression in Pichia.

Alcohol Oxidase Genes
Pichia pastoris has two genes for coding alcohol oxidase AOX1 & AOX2.AOX1 is responsible for majority of the alcohol oxidase production and it is tightly regulated by methanol.

Both AOX1&AOX2 Present - Mut+ (Methanol Utilization Plus)
Only AOX2 Present - Muts (Methanol Utilization Slow)

Advantages of Pichia Expression System
  • High Cell Density
  • Genetic Manipulation is Easy
  • Efficient Protein Processing, Protein Folding & Post-Translational Modifications.
  • Faster, Easier and less expensive to use.
  • 10-100 fold higher heterologous protein expression as compared to sacchromyces cerviseae.

Saturday, July 11, 2009

Hepatitis B

Hepatitis B is a viral disease caused by Hepatitis B Virus (HBV)which attacks liver cells resulting in inflamation. Acute illness leads to jaundice and even to death. Chronic symptoms leads to Cirrhosis and liver cancer. The Virus comes under hepadnae virus group.It is a DNA virus and it has DNA as genome patially double stranded DNA.

Structure of HBV

Source : Google Images

The HBV transmits through blood and body fluids containing blood..
1. Unprotected Sexual Contact
2. Blood Transfusion
3. Re-use of contaminated needles, etc

Hepatitis B can be prevented by Vaccination Recombinant vaccine has been developed for Surface Antigen (HBSAg)- Hepatitis B Surface Antigen.The vaccine released in the name Engerix / Recombivax

Cancer: Tumor and its genes, Causes, Treatment

Tumor is an abnormal mass of cells, which can be of Begnin type or Malignant Type.
Begnin Tumors are Loacalised to particular site while Malignant tumors can metastasize(Can Spread to different parts of the body).
Tumor is classified based on the site it occurs..

, etc

The genes responsible of tumor development are called as Oncogenes.The gene responsible for Breast cancer are BRCA I & II, for Retinoblastoma Rb, There are many factors involved in the Tumor development.

Tumor Cells

Image Souce: Google Images

There are Certain Factors which can pre-dispose to cancer some of them are

1. Tobacco Smoking, use of Gutkas,etc..
2. Increased alcohol Consumption can lead to cancer
3. Exposure to X-rays
4. Cosumtion of more animal fat


It depends on the size, stage and location of the Tumor

1. Chemotherapy : Chemical agents are used
Alkylating agents
Anticancer Antibiotics
Plant Alkaloids

2. Radiation Therapy: Radiation
3. Surgery

or combination of these

75% of the Anticancer drugs are sourced from Plants
Taxol - Taxus burgata
Vincristine and Vinblastin - VInca rosea

Monday, March 16, 2009

Structure, Replication, Symptoms, Transmission, Diagnosis and Treatment of HIV / AIDS

AIDS: Acquired Immuno Deficiency Syndrome

• AIDS is the Deadliest Pandemic in humans and it is caused by a RNA virus called Human Immunodeficiency Virus (HIV).

• AIDS is The Last Stage of  HIV Infection.

• First Identified By Dr.Luc Montagnier & His Collegues.

• It is Estimated That 8-10 Millions Adults & 1 Million Chliderns World Wide Are Infected With HIV Virus.

• AIDS is one of The Sexually Transmitted Disease.

• 73% HIV is Aquired By Sexual Contact.

• The First Aids Case In India Was In 1986 From Chennai, Since Then There Is Been A Rapid Spread Of HIV Infection All Over The Country.

• 80% Of Males & 20% Females Almost 90% With Hiv Were In The Age Group 15-40 Years.

• AIDS  Is Received From The Infected Person. So it is Said to Be Acquired.

• AIDS Is Caused By The Infection of  RNA Virus on Lymphocytes As A Result The Activity Of T-Helper Cells Is Deprsed.

• This Leads To The Supression Of The Immune System Hence The Name Immuno Defiency.

• As The Initial Infection Of Virus Pass The Way For The Development Of Complex Of  Disease . It is Called Syndrome.

AIDS Red Ribbon: Its an AIDS awareness ribbon, it is a symbol of solidarity of people living with HIV / AIDS.

AIDS Awareness Red Ribbon

Every year December 1st is observed as World AIDS day and is dedicated to raise awareness of the AIDS pandemic caused by the spread of HIV Infection.

Structure of HIV

Replication of HIV

Steps in the HIV Replication Cycle

  1. Fusion of the HIV cell to the host cell surface.
  2. HIV RNA, reverse transcriptase, integrase, and other viral proteins enter the host cell.
  3. Viral DNA is formed by reverse transcription.
  4. Viral DNA is transported across the nucleus and integrates into the host DNA.
  5. New viral RNA is used as genomic RNA and to make viral proteins.
  6. New viral RNA and proteins move to cell surface and a new, immature, HIV virus forms.
  7. The virus matures by protease releasing individual HIV proteins. 
Sources of HIV 

• HIV is Transmitted Through Unprotected Sexual Intercourse.

• 5-10% adults Are Infected By Sharing HIV  Infected Needles.

•  HIV  Is Tranmitted By Transfusion Of Infected Blood.

• A Pregant Woman With  HIV  can Pass The Virus To Her Foeteus During Pregnancy Or Child Birth.

• Some Times Woman Pass  HIV  To The Baby By Breast Milk.

Symptoms of AIDS / HIV Infection

Some of the late stage symptoms of HIV infection are:
  • Rapid weight loss
  • Recurring fever or profuse night sweats
  • Extreme and unexplained tiredness
  • Prolonged swelling of the lymph glands in the armpits, groin, or neck
  • Diarrhoea that lasts for more than a week
  • Sores of the mouth, anus, or genitals
  • Pneumonia
  • Red, brown, pink, or purplish blotches on or under the skin or inside the mouth, nose, or eyelids
  • Memory loss, depression, and other neurological disorders.
Transmission of HIV / AIDS

• Sexual Contact Both Homosexual And Hetrosexual.

• Blood Tranfusion.

• Mother To Foetus Through The Plancenta.

• Injection With Unsterile Syringes And Needles.

• Breast Feeding By Infected Mother.

Diagnosis / Detetction of HIV / AIDS

• ELISA : Enzyme Linked Immunosorbent Assay

Western Blotting

• PCR : Polymerase Chain Reaction

Control / Prevention of HIV Transmission

• Syringes, Needles & Other Materials Should Be Sterlised.

• Avoiding Of Sharing Materials.

• Screening Of Blood Before Transfussion.

• Sexual Contact With Sex Workers Should Be Avoided.

• Use Of  Condoms During Sexual Contact

Treatment for HIV/ AIDS

There are 31 antiretroviral drugs (ARVs) approved by the Food and Drug Administration to treat HIV infection. These treatments do not cure people of HIV or AIDS. Rather, they suppress the virus, even to undetectable levels, but they do not completely eliminate HIV from the body.Even after taking antiretroviral drugs an infected person can transmit the virus and must continuously take antiretroviral drugs in order to maintain their health quality.

One of these include Integrase inhibitor these helps in preventing the integration of viral genome into the host DNA.

Thursday, March 5, 2009

Indian Institute of Science Entrance Exam 2009

Indian Institute of Science (IISc) is conducting Entrance Examination for Research Programmes..
Applications can be submitted Online.

For More Details Visit

Friday, February 27, 2009

Clinical Research As a Career

Intellectual Property Rights [IPR] as Career



These are legal rights which are granted for creation of the minds.

If you have created something eg:song,poem or a book or even a new invention in biotechnology which has a commercial application or value,you are entitled to get rights for it.


Intellectual property or creation of mind or intellectual are like property that have commercial value.

They can be bought and sold just like conventional property.

Since IPR can be bought and sold just like property,we use the term “intellectual property”


IPR are needed to reward original effort.

The main concept behind all forms of IP,be it patents or copyright or industrial design etc is that the person who has put in original effort must have rights over his creation and must get rewarded for it.

He must not be cheated.

Thus IPR lead to progress and development by ensuring rights and regulations for people who put in original effort.


The first intellectual property law was passed in VENICE in 1474 which protected the investor’s interest against copying of their creation.

England soon followed the suit to grant intellectual property rights to its inventor for a limited period.

With increase in international trade intellectual property theft was on the rise.

This led the birth of Paris Convention.


Intellectual property can be broadly divided into two categories.

  • Copyright.
  • Industrial property.

International law schools:
  • George Washington University
  • Franklin Pierce Law Centre
  • Columbia University
  • Stanford University
  • New York University
In india:
  • National Law School
  • National University Of Juridical Science
  • Symbiosis Institute 
Online Resources
  • Online courses by WIPO:http://academy.wipo int
  • Basic information about IPR: and 


IPR attorneys are integral part of in-house teams of buiseness organizations formed with the sole aim of identifying and stopping copyright infringements.

IPR attorneys are also being actively employed by a whole range of organizations like Specialty Law Firms,Government and self supported think tanks,Law Enforcing Bodies and Universities.


Most of the law firms especially in developed and emerging economics like the US,India and China has specilaised divisions that cater to litigations concerning of infringement of intellectual properties.

In US there are law firms that specialize in intellectual property law.


These are one of the prolific employes of IPR attorneys.

One of the most obvious agencies is the patent and copyright office of any country.

Other departments that employ IP attorneys are defence,information technology,justice and commerce.


Universities take up projects.

These projects involve various technologies.

Thus various universities have an in-house of IPR lawyers that protect their interests.

  • Kirloskar Brothers Limited.
  • Maha India.
  • Robert Bosch Engineering.
  • General Physics Corporation
  • Harbinger Systems.
  • Heaque Creations.
  • United Health Group.

The category for IPRs most important for researchers is patents.

Knowledge of IPRs is important for researchers in many ways.

Prevents duplication of work.

Helps researchers to focus on commercially relevant research.

Prevents exploitation of workers.

Helps in revenue generation.

Prevents infringements and helps avoid litigation.


No, one Required to have fundamentals cleared.

Whether the work your doing is really original.

Is it infringing upon somebody’s rights or not?

What is the global technology status of the research work your about to start?

Whether what you have achieved in the lab is patentable or not?

You need assistance of lawyers and legal experts.


Knowledge of IPR is important for biotech industries and teaching institutes.

Basic courses of WIPO:-preference in interviews and placements.

Sought by patent attorney firms and consultancy firms.

R and D production.


Networking with R & D people and finding out whether their work is patentable or not.
Identifying technological advances of relevance to your industry vide regular monitoring.

Search patent database.

Guiding your R & D colleagues.

Indentification of new and emerging technologies.


Filing of biotechnology patents requires a sound technical knowledge.

Thus most firms are hiring M.Sc/Phd candidates having biotechnology background.


Patents filed and not commercialized are a tremendous loss of time ,money and effort.

Once rights over the work are created, inventors can freely contact and interact with industry professionals,disclosing details of their work without any fear that their work will be copied.


Demand in abroad.

Hybrid degrees.

It’s a different career.

Some Facts IPR

It’s a broad field.

Most important legal field in United States.

Most demanded specialty of intellectual property law is patent law.

This is because they are few and the demand is more.

Tuesday, February 24, 2009

Plant Growth Regulators In Agriculture

Plant Growth Regulators:

Plant hormones (also known as plant growth regulators (PGRs) and phytohormones) are chemicals that regulate a plant's growth. Plant hormones on the other hand, are not like animal hormones, they are often not transported to other parts of the plant and production is not limited to specific locations. Plants lack tissues or organs specifically for the production of hormones; unlike animals, plants lack glands that produce and secrete hormones to be moved around the body. Plant hormones shape the plant, effecting seed growth, time of flowering, the sex of flowers, its longevity, senescence of leaves and fruits, they affect which tissues grow up and which grow downward, leaf formation and stem growth, fruit development and ripening, and even plant death. Hormones are vital to plant growth and lacking them plants would be mostly a mass of undifferentiated cells.

In plants, many behavioral patterns and functions are controlled by hormones. These are “chemical messengers” influencing many patterns of plant development.
¡ Plant hormones – a natural substance (produced by plant) that acts to control plant activities. Chemical messengers.
¡ Growth Regulators
¡ Plant growth regulators – include plant hormones (natural & synthetic), but also include non-nutrient chemicals not found naturally in plants that when applied to plants, influence their growth and development.
¡ 5 recognized groups of natural plant hormones and growth regulators.
1. Auxins
2. Gibberellins
3. Cytokinins
4. Ethylene
5. Abscisic acid

Cortesy: Amit Bhaskar

Sunday, February 22, 2009

Secondary Metabolite Production In Plants

Secondary Metabolite Production in Plants-Applications

Secondary Metabolite Production

Secondary metabolites are chemical compounds and the chemical compounds produced by plants are collectively called as phytochemicals.

Secondary metabolites are those chemical compounds that do not participate in metabolism of plants. But these compounds are involved in disease resistance (from fungus, bacteria, viral, and pests), for pollination and to compact in extreme conditions of stress. The stress may be biotic or abiotic [Drought, Cold, Temparature, etc.].some of the secondary metabolites are Alkaloids, Steroids, terpenoids, essential oils, flavours, fragrance, colours & pigments.

Application of secondary metabolites
Secondary metabolites are widely used in many industrial products, some of them are
  1. Ø Nuetraceuticals
  2. Ø Textile Industry
  3. Ø Cosmoceuticals
  4. Ø Pharmaceuticals
  5. Ø Perfume Industry, etc.

Terpenoids, Steroids and steroids are used in 25% of the prescribed drugs, and almost all cancer drugs are sourced from plants. Colours and fragrances are used in textile and food industry. Some of the plant species that produce the secondary metabolites of great industrial importance. Like Taxas burgata which produce Taxol is used in cancer treatment, all parts of the plant has the capacity to produce this compound.Coleus forskohli which produces the compound Forskohlin is used in treatment for Glaucoma, only roots are capable of producing the secondary metabolite in this plant. Lithospermum erythrorhizon which produce Shinkonin.

Production of secondary metabolites

The process of invitro culture of cells for the large scale production of secondary metabolite is complex, and involves the following aspects
  1. Ø Developing Mother Culture
  2. Ø Selection of cell lines for high yield of secondary metabolites.
  3. Ø Large scale cultivation of plant cells
  4. Ø Medium composition and effect of nutrients
  5. Ø Elicitor induced production of secondary metabolites
  6. Ø Effect of environmental factors
  7. Ø Biotransformation using plant cell culture
  8. Ø Secondary metabolites and analysis.
Developing Mother Culture

The culture, which is produced, first is called mother culture. Different cultures has been developed like callus, multiple shoots, roots, etc among these which of the culture can be produced easily, will be selected for further culturing.
The callus can be developed from explant or from a mother culture, which is already developed. Different types of callus can be obtained like Nodular Callus, Friable Callus Pigment Callus, Embryonic Callus, etc. among those friable callus (loosely packed callus) is preferred. If friable callus is not producing it can be induced by certain treatments. When the friable callus is put in liquid medium and kept in shaker the cells of the callus will get dissociated. Usually 75ml of the media is taken in 250ml flask, the optimum inoculating density is 5mg / 75ml, the pH of the medium should be 5.6.the flask is kept in a Gyratory Shaker at 120 rpm, which is for the aeration of the medium. The speed varies depending on the plant species.

Sub Culturing:

Sub culturing can be done when the cells are in the exponential stage, the stage of development can be identified by growth pattern studies. The culturing can be done by batch culture or by continous culture. One of the method is 5ml of inoculum from the suspension [75ml] is transferred 70ml of fresh medium. Like this way 15 or more flasks of culture can be produced. Another method is that, divide the media equally into two parts and add the fresh media to make-up to 75ml and this process is continued.
For identification of the stage and analysis of the product growth pattern studies are very much important. Growth study is done for 25days form the starting. For studying growth different methods (Optical Density, Dry weight, Cell counting) can be used. By this we can know the Packed Cell Volume (PCV) along with that content analysis also can be done so we will get a clear idea that on particular day at a particular stage of growth the cell is producing the secondary metabolite. Moreover the target of the product also can be known,ie. Whether it is produced Intracellular or Extracellular.

Callus Culture
Callus Culture

Selection of cell lines for high yield of secondary metabolites 
The purpose of tissue culture is to produce high amount of secondary metabolite, but in general majority of the callus and suspension cultures produce less quantity of secondary metabolites. The reason for this is mainly due to the lack of fully differentiated cells in the cultures. There are some techniques ultimately useful for the separation of producers and non-producers. The techniques employed for this are cell cloning, Visual and Chemical analysis and selection for resistance.

Cell Cloning:

This is a simple procedure and involves the growth of single cells (taken from suspension culture) in a suitable medium. Each cell population is then screened for secondary metabolite formation. The cells with high ability are selected and maintained by subcloning.

Aggregate Cell Cloning:

A high yielding plant of desired metabolite is selected and its explants are cultured on a solid medium. After establishing callus cultures, high metabolite producing calluses are identified, and they are grown in suspension cultures. Cell aggregates from these cultures are grown on solid medium. The freshly developed cell aggregates are divided into two parts. One half is grown further, while the other half is used for the quantitative analysis of the desired metabolite produced. The cell lines with high yield of secondary metabolites are selected and are used for scale-up in suspension cultures. This is followed large-scale tissue culture in a bioreactor.

Visual or Chemical Analysis:
A direct measurement of some of the secondary metabolites produced by cell lines can be done either by visual or chemical analysis.
Visual identification of cell lines producing coloured secondary metabolites will help in the selection of high-yielding cells. This method is simple but the limitation is that the desired metabolite should be coloured.The chemical analysis can be done in some colonies derived from single cell cultures.Radioimmunoassay is the most commonly used, Microspectrophotometry and fluorescent antibody techniques are also been used.

Selection for Resistance:
Certain cells resistant to toxic compounds may lead to the formation of mutant cells, which can overproduce a primary metabolite, and then a secondary metabolite. Such mutants can be selected and used to produce the desired metabolite in the large quantities.

Large Scale Cultivation of Plant Cells
To achieve industrial production of the desired metabolite, large-scale cultivation of the plant cell is required. Plant cells when cultured exhibit changes in volumes and thus variable shapes and sizes. Further, cultured cells have low growth rate and genetic instability. All these aspects have to be considered for the mass cultivation of cells. the following four different culture systems are widely used:

1. The Free-Cell Suspension Culture
2. Immobilized Cell culture
3. Two Phase System culture
4. Hairy root culture

The Free-Cell Suspension Culture:
Mass cultivation of plant cells is most frequently carried out by cell suspension cultures. Care should be taken to achieve good growth rate of cells and efficient formation of the desired secondary metabolite. Many specially designed bioreactors are in use for free-cell suspension cultures.

Bioreactors for the Production of Secondary metabolites
  • Batch Bioreactors
  • Continuous Bioreactors
  • Multistage Bioreactors
  • Airlift Bioreactors
  • Stirred Tank Bioreactors
Two important aspects should be considered for good success of suspension cultures
  1. Adequate and Continous Oxygen Supply
  2. Minimal generation of hydrodynamic stresses due to aeration and agitation.
Immobilized Cell Cultures

Plant cells can be made immobile or immovable and used in culture systems. The cells are physically immobilized by entrapment. Besides individual cells it is possible to immobilize aggregate cells or even calluses. Homogenous cell suspensions are more suitable for immobilization.

Surface immobilized plant cell (SIPC) technique efficiently retains the cells and allow them to grow at a higher rate. When the cells are immobilized there is a better cell-cell contact, and the cells are protected from high shear and stresses. All these helps in the maximal production of secondary metabolite.
The common methods used for entrapment are

Entrapment of cells in gels: The cells / protoplast can be immobilized in several gels.Eg: Alginate,agarose,carrageenin.The gels may be either used individually or in combination.The techniques involved for immobilization of plant cells are comparable to those used for the immobilization of microorganism or other cells 

Entrapment of cells in nets or foams: Polyurethane or nets with various pore sizes are used.The actively growing plant cells in suspension can be immobilized on these foams.The cells divide within the compartments of foam and foam aggregates.
Entrapment of cells in hollow-fibre membranes: Tubular hollow fibres composed of cellulose acetate silicone polycarbonate and organized into parallel bundles are used for immobilization of cells.It is possible to entrap cells between the fibres

Bioreactors for use of immobilized cells

Fluidized bed or fixed bed bioreactors are employed to use immobilized cells for large scale cultivation. In fluidized bed bioreactors, the immobilized cells are agitated by a flow of air or by pumping the medium. In contrast, in the fixed bed bioreactor, the immobilized cells re kept stationary (not agitated) and perfused at a slow rate with an aerated culture medium. The list of plant species which immobilized cells employed for the production of secondary metabolites

Two Phase System Culture
Plant cells can be cultivated in an aqueous two phase system for production of secondary metabolites. In this technique cells are kept apart from the product by separation in the bioreactor. This is advantageous since the product can be removed continuously. Certain polymers are used for the separation of the phases.Various products have been used for phase separation. Hooker and Lee cultured tobacco cells in aqueous two phase compraising of Dextran & PEG for the production of phenolic compounds.Silicon fluid has been used for the phase separation of Eschscholtzia californica cell cultures.This fluid enhanced benzophenan-thridine alkaloids three fold compared to single phase culture.

Hairy Root Culture
Hairy root cultures are for the production of root-associated metabolites. In general, these cultures have high growth rate and genetic stability.
For the production of hairy root cultures, the explant material is inoculated with pathogenic bacterium, Agrobacterium rhizogenes. The organism contains root-inducing (Ri) plasmid that causes genetic transformation of plant tissues, which finally results in the hairy root cultures. Hairy roots produced by plant tissues have metabolite features similar to that of normal tissues.

Elicitor-induced production of secondary metabolites
The production of secondary metabolites in plant cultures is generally low and does not meet the commercial demands. the synthesis of majority of secondary metabolites involves multistep reactions and many enzymes. It is possible to stimulate any step to increase product formation.
Elicitors are the compounds of biological orgin, which stimulate the production of secondary metabolites, and the phenomenon of such stimulations are called as elicitation.
Elicitors produced within the plant cells are called as endogenous elicitors (Eg: Pectin, pectic acid and other polysaccharides) when the elicitors are produced by microorganisms they are called as exogenous elicitors (Eg: Chitins, Glucans). All the elicitors of biological orgin are biotic elicitors. Physical (Cold, Heat, UV light, etc.) and chemical agents (ethylene, fungicides, antibiotics) can also increase product formation such elicitors are called as abiotic elicitors.

Factors affecting Secondary Metabolite production

There are various factors affecting Secondary metabolite production, some of the major factors includes
  1. Light
  2. Incubation Temperature
  3. pH of the medium
  4. Aeration of the culture, etc
All these factors will have determinal effect on the production of secondary metabolite.

Biotransformation using plant cell cultures

The conversion of one chemical into another (ie, a substrate into a final product) by using biological systems (ie, cell suspensions) as biocatalysts is regarded as Biotransformation or bioconversion the biocatalyst may be free or immobilized, and the process of Biotransformation involve one or more enzymes.
The biotechnological application of plant cell cultures in Biotransformation reactions involves the conversion of some less important substances to valuable medicinal or commercially important products. In Biotransformation, it is necessary to select such cell lines that possess the enzymes for catalyzing the desired reactions. Eg: hydroxylation, reduction, and glycosylation.

Male Sterility in Plants

Male Sterility

Plant that do not produce viable, functional pollen grains.

Male Sterility: An inability to produce or to release functional pollen as a result of failure of formation or development of functional stamens, microspores or gametes

Types of Sterility

Three types of sterility:
  • “Pollen sterility” in which male sterile individuals differ from normal only in the absence or extreme scarcity of functional pollen grains (the most common and the only one that has played a major role in plant breeding).
  •  “Structural or staminal male sterility” in which male flowers or stamen are malformed and non functional or completely absent
  • “Functional male sterility” in which perfectly good and viable pollen is trapped in indehiscent anther and thus prevented from functioning

Classification of Male Sterility

Based on its inheritance or origin:

1. Cytoplasmic male sterility (CMS) = sterile cytoplasm (S)

Male sterility comes about as a result of the combined action of nuclear genes and genic or structural changes in the cytoplasmic organellar genome

maternally inherited

2. Nuclear male sterility (NMS) = Genic, genetic, mendelian

Male sterility is governed solely by one or more nuclear genes

Nuclear inherited

3. Non genetic, chemically induced male sterility
Application of specific chemical (gametocides or chemical hybridizing agents)

Stamen (anther and filament) and pollen grains are affected

It is divided into:

a. Autoplasmic

CMS has arisen within a species as a result of spontaneous

mutational changes in the cytoplasm, most likely in the

mitochondrial genome

b. Alloplasmic

CMS has arisen from intergeneric, interpecific or occasionally

intraspecific crosses and where the male sterility can be

interpreted as being due to incompatibility or poor co-operation

between nuclear genome of one species and the organellar

genome another

CMS can be a result of interspecific protoplast fusion

Cytoplasmic Male Sterility


1. Intergeneric crosses

2. Interspecific crosses

3. Intraspecific crosses

4. Mutagens (EMS, EtBr)

5. Antibiotic (streptomycin and Mitomycin)

6. Spontaneus

CMS Mechanism of Action

1. Abnormal behavior of the tapetum in the anther

2. Genetic determinant of CMS reside in mitochondria

3. Nuclear gene control the expression of CMS

CMS Limitations 

1. Pleiotropic negative effect of the CMS on agronomic quality performance of plants in the CMS cytoplasm

2. Enhanced disease susceptibility

3. Complex and environmentally unstable maintenance of male sterility and/or male fertility restoration

4. Inability to produce commercial quantities of hybrid seed economically because of poor floral characteristic of cross pollination

Utilization of CMS

1. It provides a possible mechanism of pollination control in plants to permit the easy production of commercial quantities of hybrid seeds

2. It consists of a male sterile line (the A-line), an isogenic maintainer line (The B line), and if necessary also restore line (the R-line)

3. A lines are developed by back-crossing selected B-lines to a CMS A-line for 4 – 6 times to generate a new A-line

4. B and R-lines are developed by similar back cross procedures using a CMS R-line as female in the original cross and a new line as the recurrent parent in 4 – 6 backcrosses

Nuclear Male Sterility [NMS]

1. Originated through spontaneous mutation or mutation by ionizing radiation and chemical mutagens such as ethyl methane sulphonate (EMS) and ethyl imine (EI) or by genetic engineering, protoplast fusion, T-DNA transposon tagging and affecting the synthesis of flavonoids

2. can probably be found in all diploid species

3. Usually controlled by mutations in genes in the single recessive genes affect stamen and pollen development, but it can be regulated also by dominant genes

Methods of Inducing Male Sterility

1. Through Chemical Agents

2. Through Recombinant DNA (rDNA) Technology

Chemical Agents Used

1. Plant hormones/hormones antagonists

a. auxins and auxin antagonists (NAA, IBA, 2,4-D, TIBA, MH)

b. Gibberellins and antagonist (GA3, GA4+7, CCC: 2-chloroethyl-trimethyl ammonium chloride)

c. Abscisic acid

2. Other substances

a. LY195259

b. TD1123

Recombinant Methods

Targetting the expression of a gene encoding a cytotoxin by placing it under the control of an ather specific promoter (Promoter of TA29 gene)

Expression of gene encoding ribonuclease (chemical synthesized RNAse-T1 from Aspergillus oryzae and natural gene barnase from Bacillus amyloliquefaciens)

RNAse production leads to precocious degeneration of tapetum cells, the arrest of microspore development and male sterility. It is a dominant nuclear encoded or genetic male sterile (GMS), although the majority of endogenous GMS is recessive

Fertility Restoration

Restorer gene (RF) must be devised that can suppress the action of the male sterility gene (Barstar)
a specific inhibitor of barnase

Also derived from B. amyloliquefacien Served to protect the bacterium from its own RNAse activity by forming a diffusion-dependent, extreemely one to one complex which is devoid of residual RNase activity

The use of similar promoter to ensure that it would be activated in tapetal cells at the same time and to maximize the chance that barstar molecule would accumulate in amounts at least equal to barnase

Inhibiting the male sterility gene by antisense. But in the cases where the male sterility gene is itself antisense, designing a restorer counterpart is more problematic

Strategies to Propagate Male-Sterile Plant

1. Selection by herbicide application

2. Inducible sterility

3. Inducible fertility

4. Two-component system

Tuesday, February 10, 2009

Tuberculosis : "Mammalian Tubercle Bacilli"

Tuberculosis is a chronic infection caused by the bacteria Mycobacterium tuberculosis (and occasionally other variants of Mycobacterium). It usually involves the lungs, but other organs of the body can also be involved
Only about 10 percent of those infected with TB develop the disease. The first symptoms of an active case of TB may be so commonplace that they are often dismissed as the effects of a cold or flu. The individual may get tired easily, feel slightly feverish or cough frequently. It usually goes away by itself, but about in about half the cases, it will return.
BCG VAccine is given through out many parts of the world.

Monday, February 9, 2009

Polymerase Chain Reaction: Copying DNA is Copyright Protected???

Polymerase Chain Reaction is used for the amplification of DNA of an organism.Amplification means copying. Is the copying of DNA is copyright protected.. ..
More info on Polymerase Chain Reaction is available on these sites...
Polymerase Chain Reaction
Polymerase chain reaction (PCR) enables researchers to produce millions of copies of a specific DNA sequence in approximately two hours. This automated process bypasses the need to use bacteria for amplifying DNA.
In nature, most organisms copy their DNA in the same way. The PCR mimics this process, only it does it in a test tube. When any cell divides, enzymes called polymerases make a copy of all the DNA in each chromosome. The first step in this process is to "unzip" the two DNA chains of the double helix. As the two strands separate, DNA polymerase makes a copy using each strand as a template.

The four nucleotide bases, the building blocks of every piece of DNA, are represented by the letters A, C, G, and T, which stand for their chemical names: adenine, cytosine, guanine, and thymine. The A on one strand always pairs with the T on the other, whereas C always pairs with G. The two strands are said to be complementary to each other.



Biofertilizer: Eco-Friendly

One of the major concerns in today's world is the pollution and contamination of soil. The use of chemical fertilizers and pesticides has caused tremendous harm to the environment. An answer to this is the biofertilizer, an environmentally friendly fertilizer now used in most countries. Biofertilizers are organisms that enrich the nutrient quality of soil. The main sources of biofertilizers are bacteria, fungi, and cynobacteria (blue-green algae). The most striking relationship that these have with plants is symbiosis, in which the partners derive benefits from each other.

Image Source: Google Images

The setup is made to treat liquid as well as solid wastes.Rejuvenation of Soil & healthy Plant & soil relationship. Conversion of Bio-waste into organic bio-fertilizers.Unique microbial and vermiculture conversion technology.7,000 MT of bio-fertilizers to be produced per annum.Pioneering work to develop an unique process.

Gene Therapy : A New Approach

Each of us carries about half a dozen defective genes. We remain blissfully unaware of this fact unless we, or one of our close relatives, are amongst the many millions who suffer from a genetic disease. About one in ten people has, or will develop at some later stage, an inherited genetic disorder, and approximately
One of the most amazing genetic applications in medicine is gene therapy. Also known as somatic gene therapy and therapeutic gene therapy, this procedure involves inserting (or sometimes deleting) portions of the genes in diseased patients so that they can be cured and live healthier lives

Ethical Issues on GM Crops

Although "biotechnology" and "genetic modification" commonly are used interchangeably, GM is a special set of technologies that alter the genetic makeup of organisms such as animals, plants, or bacteria. Biotechnology, a more general term, refers to using organisms or their components, such as enzymes, to make products that include wine, cheese, beer, and yogurt.

Combining genes from different organisms is
Humans were modifying crops long before the advent of genetics and "modern" biotechnology. Once humans began to practice settled agriculture some 8000 years ago, they selected which plants to plant, grow, and harvest-first choosing from the wild and then from cultivated crops.

Saturday, February 7, 2009

Stem Cells: As regenerative Medicine

Sources of Stem Cells
Research on stem cells is advancing knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. This promising area of science is also leading scientists to investigate the possibility of cell-based therapies to treat disease, which is often referred to as regenerative or reparative medicine.
Stem cells are one of the most fascinating areas of biology today. But like many expanding fields of scientific inquiry, research on stem cells raises s
Stem Cells

Image source: Google Images

Nanotechology: Introduction, Types & Nanoparticles

Nanotechnology Introduction

The term "nanotechnology" has evolved over the years via terminology drift to mean "anything smaller than microtechnology," such as nano powders, and other things that are nanoscale in size, but not referring to mechanisms that have been purposefully built from nanoscale components

Image source: google images

Nanotechnology Basics
Coined as "nano-technology" in a 1974 paper by Norio Taniguchi at the University of Tokyo, and encompassing a multitude of rapidly emerging technologies, based upon the scaling down of existing technologies to the next level of precision and miniaturization. Taniguchi approached nanotechnology from the 'top-down' standpoint, from the viewpoint of a precision engineer.

Types: Nanoparticles

Extensive libraries of nanoparticles, composed of an assortment of different sizes, shapes, and materials, and with various chemical and surface properties, have already been constructed. The field of nanotechnology is under constant and rapid growth and new additions continue to suppliment these libraries. The classes of nanoparticles listed below are a

Friday, February 6, 2009

Transgenic Sweet Potatoes

Transgenic sweet potato plants carrying the delta-endotoxin gene from Bacillus thuringiensis var. tenebrionis.

Image from Google images


Sweet potato is a major crop that feeds millions of people in the developing world. It is especially popular among farmers with limited resources, and produces more biomass and nutrients per hectare than any other food crop in the world. New biotechnological approaches may enable scientists to rapidly develop superior, disease and pest resistant cultivars.

Sweet potato (Ipomoea batatas L.) is adaptable to a broad range of agro­ecological conditions and fits in low­input agriculture. It is highly productive even under adverse farming conditions. Sweet potato is grown in more than 100 countries as a valuable source of food, animal feed and industrial raw material. It is a staple crop in many South­East Asian and African countries.


Golden Rice -

In Golden Rice two genes have been inserted into the rice genome by genetic engineering, to account for the turned-off genes. This intervention leads in turn to the production and accumulation of β-carotene in the grains. The intensity of the golden colour is an indicator of the concentration of β-carotene in the endosperm.

Image from Google images
Fowler, Plant Biotechnology

Transgenic Plants for Crop Improvement

Transgenic crops are now grown commercially on several million hectares, principally in North America. To date, the predominant crops are maize (corn), soybean, cotton, and potatoes. In addition, there have been field trials of transgenics from at least 52 species including all the major field crops, vegetables, and several herbaceous and woody species. This review summarizes recent data relating to such trials, particularly in......

Source:Journal of Experimental Botany

Plant Hormones and Growth Regulators

Plant hormones and growth regulators are chemicals that affect flowering; aging; root growth; distortion and killing of leaves, stems, and other parts; prevention or promotion of stem elongation; color enhancement of fruit; prevention of leafing and/or leaf fall; and many other conditions. Very small concentrations of these substances produce major growth changes.

image source: google images

Palnt Grorth Regulators are responsible for the growth and development of the plants..

What is a hormone?
As plants grow their genotype is expressed in the phenotype which is modified by the environmental conditions that they experience. Somehow the rates of growth and differentiation of cells in different parts of the plant are coordinated in response to these inputs.

Suggested Books for this Topic:

Bhan (1998), Tissue Culture Mittal Publications, New Delhi

Gupta P.K, Elements of Biotechnology, Rastogi & Co.

Dr. U. Satynarayana, Biotechnology

Media Preparation Plant Tissue Culture

Media Preparation - Media making can be time consuming. Nowadays the plant tissue culture media most commonly used are available in the market as dry powders. The simplest method of preparing media is to dissolve these powders containing inorganic and organic nutrients in some quantity of distilled water. After the contents have been thoroughly mixed in water,


*above image is from Google Images

Suggested Books for this Topic:

Bhan (1998), Tissue Culture Mittal Publications, New Delhi
Gupta P.K, Elements of Biotechnology, Rastogi & Co.
Dr. U. Satynarayana, Biotechnology

Plant Tissue Cultre Media

Plant tissue culture is the aseptic (free from microorganism) culture of any plant part in vitro. Micro-propagation is the rapid vegetative propagation of plants via tissue culture techniques. Micro-propagation permits the manipulation of physical and chemical conditions in the production of large numbers of high quality plant material within a short period of time.

Human Genome Project

Completed in 2003, the Human Genome Project (HGP) was a 13-year project coordinated by the U.S. Department of Energy and the National Institutes of Health. During the early years of the HGP, The Project Goals and Ethical, Legal and Social Issues,etc ....

Tuesday, February 3, 2009

Cytoplasmic Male Sterility in Plants

Male Sterility

Plants with male sterility don’t produce functional / viable pollen grains.
Male Sterility is of two types:
Cytoplasmic Male sterility
Genic Male sterility

Advantages of Male Sterility & Its Importance in Plant Biotechnology

In palnt breeding to obtain hybrids cross pollination need to be done among selected parental lines High level of self pollination any occur especially in bisexual plants. This hampers hybrid seed production to overcome this problem and ensure crosses between the selected female and selected male, several types of pollination control need to be used.

Mannual emasculation
Self Incompatibility
male Gametocides
Use of genetically Engineered Systems for Male Sterility

Male sterility in plants may be nuclear or Cytoplasmic. Cytoplasmic male sterilityis invariably due to defective functioning of to the tapetum of the anthers. The main function of tapetum is to supply nutrients to developing pollen grains. So far 40 plant species are reported to have Cytoplasmic male sterility.
In maize there are specific nuclear genes which are called as fertility restoring genes (Rf). Rf genes restore polar fertility after crossing. In such case when male sterile plants with CMS is crossed with maize with Rf genes produce male fertile plants. Hence the defect from Mitochondrial function can be corrected by product encoded by nuclear genome of restorer maize.
Cytoplasmic male sterility is due to presence of additional DNA sequence in mitochondria designated as T-urf13, that codes for 13000 molecular weight polypeptide.
Restorer nuclear genome suppresses the synthesis of this polypeptide.CMS has become a major focus in Agriculture Biotechnology
In plant breeding two parental types are crossed to produce high yielding varities. Hybrid vigour or heterosis expressed only in F1 generation. Yield reduces rapidly with subsequent generations. Hence to cross two parental types the anthers of Female plant i.e., Seed producing plant is either removed or emasculated. This process is a labour intensive process and it is impractical. to perform on large scale.
Hence CMS lines play a role as they are genetically emasculated. These CMS lines are not capable of producing viable pollen, emasculation is not necessary to produce hybrid seeds. During hybrid seed production 3 lines of plants are maintained.

A – Line (Hybrid Seed Producing Parent) with CMS (defective mitochondrial genes) and recessive restorer genes in the nucleus.
B – Line: These are called as maintainers. This maintainers have normal(N) cytoplasmic genes but recessive restorer genes.
C- Line: Restorer Plant. They have normal cytoplasm and dominant nuclear restorer genes.
When A line is Crossed with B line

Both Cytoplasmic and nuclear Normal Cytoplasm but Nuclear
Male sterility.No viable pollen male sterility because of normal cytoplasm viable pollen
(Female) are produced

Hybrid Plant
(Maintainer Plants)
No viable Pollen

Cytoplasmic Male Sterility [CMS]

Cytoplasmic Male Sterility is noticed in more than 150 species. Cytoplasmic Male Sterility is invariably due to defects in mitochondrial genome and it is exclusively maternally inherited. Female fertility is not affected by Cytoplasmic male sterility. Palnts with Cytoplasmic male sterility do produce seeds if viable pollen is provided.
To increase crop productivity, in recent years there has been the development of hybrid cultivar in a wide range of crops crosses between genetically distinct parental lines or populations give rise to progeny that exhibit heterosis or hybrid vigor. Hybrids in general are more resistant to disease and insects, less suceptible to environmental stress and yield more seed.
Inorder to do cross pollination CMS is most beneficial factor as it is not needed to emasculate the flower which is practically very difficult to perform in minute flowers.
The CMS is mainly due to defective functioning of tapetum of the anther. The main function of pollen is to supply nutrients to developing pollen grains. In nature CMS orginates because of intergenc crosses, Interspecific crosses,