Phytohaemagglutinin

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Phytohaemagglutinin

Phytohaemagglutinin (PHA, or phytohemagglutinin) is a lectin

Lectin

Lectins are sugar-binding proteins which are highly specific for their sugar moieties. They typically play a role in biological recognition phenomena involving cells and proteins....
found in plants, especially bean

Bean

Bean is a common name for large plant seeds of several genus of the Family Fabaceae used for human food or animal feed.The whole young pods of bean plants, if picked before the pods ripen and dry, can be tender enough to eat whole, whether cooked or raw....
s. PHA actually consists of two closely related proteins, called Leucoagglutinin (PHA-L) and PHA-E. The letters E and L point to the fact that these proteins agglutinate Erythrocytes and Leukocytes, respectively. It is found in the highest concentrations in uncooked red kidney beans and white kidney beans (also known as cannellini), and it is also found in lower quantities in many other types of green beans and other common beans (Phaseolus vulgaris), as well as broad beans (Vicia faba) such as fava beans.

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Phytohaemagglutinin (PHA, or phytohemagglutinin) is a lectin

Lectin

Bean

Toxin

A toxin is a poisonous substance produced by living cells or organisms. For a toxic substance not produced by living organisms, "toxicant" is the more appropriate term, and "toxics" is an acceptable plural....
.

The lectin has a number of effects on cell metabolism: it induces mitosis

Mitosis

Mitosis is the process in which a eukaryotic cell separates the chromosomes in its cell nucleus, into two identical sets in two daughter nuclei....
, and affects the cell membrane in regard to transport and permeability

Semipermeable membrane

A semipermeable membrane, also termed a selectively-permeable membrane, a partially-permeable membrane or a differentially-permeable membrane, is a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion." The rate of passage depends on the press...
to proteins. It agglutinates

Agglutination (biology)

Agglutination is the clumping of particles. The word agglutination comes from the Latin language agglutinare, meaning "to glue to."This occurs in biology in three main examples:...
most mammalian red blood cell

Red blood cell

Red blood cells are the most common type of blood cell and the vertebrate body's principal means of delivering oxygen to the body tissues via the blood....
types.

As a toxin it can cause poisoning in monogastric

Monogastric

A monogastric organism has a simple single chambered stomach, and is the alternate gastric complex to a four-chambered complex stomach known as a ruminant. Examples of monogastric animals include humans, pigs, dogs, and cats....
animals, such as humans, through the consumption of raw or improperly prepared kidney beans. Measured in haemagglutinating units (hau) a raw red kidney bean can contain up to 70,000 hau. This can be reduced around 200-fold by correct cooking (boiling for at least ten minutes). Cooking at 80 Celsius can raise the available hau up to fivefold. The bean also contains a-amylase inhibitor.

Poisoning can be induced from as few as five raw beans and symptoms occur within three hours, beginning with nausea then vomiting which can be severe and sustained (profuse), then diarrhea. Recovery occurs within four or five hours of onset, usually without the need for any medical intervention.

Medically it is used as a mitogen

Mitogen

A mitogen is a chemical substance, usually some form of a protein, that encourages a cell to commence cell division, triggering mitosis.Mitogens trigger signal transduction pathways in which mitogen-activated protein kinase is involved, leading to mitosis....
to trigger cell division in T-lymphocytes, and to activate latent HIV

HIV

Human immunodeficiency virus is a lentivirus that can lead to AIDS , a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections....
-1 from human peripheral lymphocyte

Lymphocyte

A lymphocyte is a type of white blood cell in the vertebrate immune system.By their appearance under the light microscope, there are two broad categories of lymphocytes, namely the large granular lymphocytes and the small lymphocytes....
s. PHA-L is used by neuroscientists

Neuroscience

Neuroscience is a field devoted to the scientific study of the nervous system. The Society for Neuroscience was founded in 1969, but the study of the brain started a long time ago....
to trace the path of efferent

Efferent

Efferent is an anatomical term with the following meanings:*Conveying away from a center, for example the Efferent arterioles conveying blood away from the Bowman's capsule in the Kidney....
axon

Axon

An axon or nerve fiber is a long, slender projectionof a nerve cell, or neuron, that conducts action potentialaway from the neuron's cell body or soma....
s of neuron

Neuron

Neurons are responsive cell in the nervous system that process and transmit information by electrochemical Signal . They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves....
s. This usage is called the anterograde labeling method.

Phytohaemagglutinin

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