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Sunday, May 22, 2011

Chemotaxis

Chemotaxis


Chemotaxis is the phenomenon in which somatic cells, bacteria, and other single-cell or multicellularglucose) by swimming towards the highest concentration of food molecules, or to flee from poisons (for example, phenol). In multicellular organisms, chemotaxis is critical to early development (e.g. movement of spermfertilization) and subsequent phases of development (e.g. migration of neurons or lymphocytes) as well as in normal function. In addition, it has been recognized that mechanisms that allow chemotaxis in animals can be subverted during cancer metastasis. organisms direct their movements according to certain chemicals in their environment. This is important for bacteria to find food (for example, towards the egg during
Chemotaxis is called positive if movement is in the direction of a higher concentration of the chemical in question, and negative if the direction is opposite.

Neutrophils are the body's first line of defense against bacterial infections. After leaving nearby blood vessels, these cells recognize chemicals produced by bacteria in a cut or scratch and migrate "toward the smell". The above neutrophils were placed in a gradient of fMLP (N-formyl-methionine-leucine-phenylalanine), a peptide chain produced by some bacteria. Although migration of cells was detected from the early days of the development of microscopy (Leeuwenhoek), erudite description of chemotaxis was first made by T W. Engelmann (1881) and W.F. Pfeffer (1884) in bacteria and H.S. Jennings (1906) in ciliates. The Nobel Prize laureate I. Metchnikoff also contributed to the study of the field with investigations of the process as an initial step of phagocytosis. The significance of chemotaxis in biology and clinical pathology was widely accepted in the 1930s. The most fundamental definitions belonging to the phenomenon were also drafted by this time. The most important aspects in quality control of chemotaxis assays were described by H. Harris in the 1950s. In the 1960s and 1970s, the revolution of modern cell biology and biochemistry provided a series of novel techniques which became available to investigate the migratory responder cells and subcellular fractions responsible for chemotactic activity. The pioneering works of J. Adler represented a significant turning point in understanding the whole process of intracellular signal transduction of bacteria.
On November 3, 2006, Dr. Dennis Bray of University of Cambridge was awarded the Microsoft Award for his work on chemotaxis on E. coli.


Saturday, May 21, 2011

ENDOSULFAN

 
Endosulfan - to be or not to be banned for us to be or not to be
It is a major insecticide generally used in the farms for removal of pests and insects.  In comparison to other pesticides endosulfan has a higher success rate in doing its job.  It is an off-patent organochlorine insecticide and acaricide that is being phased out globally. Endosulfan became a highly controversial agrichemical due to its acute toxicity, potential for bioaccumulation, and role as an endocrine disruptor.  Because of its threats to human health and the environment, a global ban on the manufacture and use of endosulfan was negotiated under the Stockholm Convention in April 2011. The ban will take effect in mid 2012, with certain uses exempted for 5 additional years. More than 80 countries, including including the European Union, Australia and New Zealand, several West African nations, the United States, Brazil and Canada had already banned it or announced phase outs by the time the Stockholm Convention ban was agreed upon. It is still used extensively in India, China, and few other countries. It is produced by Makhteshim Agan and several manufacturers in India and China. 
It was discovered first in Europe and US and was widely used till the ill effects are accepted.  Although it kills the pests in the farm products successfully the residue has the same effects on the humans as well when consumed.  The chemical can not be destroyed.  It has got the ability to pass through generations.  It can penetrate land, air, and for that matter can cause damage everywhere.  The damages of this chemical are also said to have been found in Antartica as well. 
In the recently held Stockholm convention out of 174 countries 125 countries decided to ban this chemical while 47 countries were in dilemma for this decision and remained silent.  There was only one country that opposed the implementation of ban on this draconian pesticide that can cause damage to the homo sapiens in toto.  Surprisingly and unfortunately it is India.  The reason the Government of India expressed was that it could not find any alternative pesticide to endosulfan.  The farming in India is thousands of years old and is not a profession in India neither it is a business rather it is the culture of we Indians governed by geographical advantages.  The natural agriculture is considered to be the best one in India.  Some of the states like Andhra Pradesh have induced the agriculturists to shift back to natural agriculture instead of modern agriculture.  Neem is the best pesticide in India used by the farmers from time immemorial.  Just adding neem with the fertilizer will give an excellent result.  Total production of endosulfan in India is 8500 tons.  It is a 4000 crore industry.  Perhaps, this is what attracts the government to struggle for getting permission for the usage of this substance for the next five years.  
Thousands of people are affected in India due to the consumption of endosulfan.  Specifically the state of Kerela more particularly in the Kasacode region many are affected by cancer and neurological diseases.  The land absorbs the toxicity and Government of Kerela banned this substance in the state followed by Karnataka.  Many agencies and associations have represented the people and demanded the ban to be implemented in India.
So now a basic question remains wether the elected representatives take decisions in favour of the people or influenced by the industrialists.  However nothing can be compromised for human lives.  Time to think.  Please post ur comments on the blog guys.