Bacteria Genomes - LACTOBACILLUS ACIDOPHILUS

L. acidophilus is a member of one of the eight main genera of lactic acid bacteria. Each genus and species have different characteristics but they are generally chained cocci or rod shaped Gram-positive , nonmotile, nonsporulating bacteria that produce lactic acid as a major or sole product of fermentative metabolism and use lactose as their main source of carbon to produce energy. L. acidophilus grows in or without the presence of oxygen, is able to live in highly acidic environments of pH 4-5 or lower and is characterised as a homofermentative ie produces lactic acid as its sole product.

L. acidophilus is probably the best well-known species of Lactobacillus, it is naturally found in the human and animal GI tract, mouth and vagina.

It has been suggested that L. acidophilus is a beneficial or so-called "friendly" bacteria which provides an important function in the body." Friendly" microorganisms are called probiotics, meaning "for life." Researchers are increasingly more convinced that probiotics are an essential link in proper health and well-being and above all help the body to get more nutrition out of the food we eat.

Few microorganisms are found in the stomach because of its high acidity, their numbers increase dramatically the further down the intestinal tract. The greatest numbers and variety are found in the large intestine. When these microbial populations are in balance, optimum health is generally achieved. For instance, probiotics keep harmful pathogenic species in check. Without sufficient numbers of viable, friendly bacteria, our intestinal ecology is thrown off balance, resulting in a wide range of possible health problems and disease conditions. Friendly bacteria attach themselves to the intestinal wall and produce a mildly acidic environment (primarily lactic acid) that curbs the growth of harmful, disease-causing bacterial species. Friendly microflora are also essential in nutrient assimilation, producing many important enzymes and increasing the bioavailability of vitamins, particularly the Bs and K, fatty acids, lactase, and calcium. Among other benefits are the strengthening of the immune system, neutralisation of toxins, normalisation of bowel movements, control of cholesterol, the countering of allergies and skin problems, and the prevention of yeast and fungal infections. In its support of the immune system, probiotics have been used in alleviating chronic fatigue syndrome.

Test tube studies have shown that L. acidophilus can inhibit the growth of candida albicans (candidiasis), the fungus associated with "thrush" in the mouth, esophagus or vagina and varying levels of success have been reported using yogurt and L. acidophillus as a treatment for vaginal candidiasis.

Researchers are also interested in the possibilities that L. acidophilus may be implicated in the relief of athritis symptoms and counter the side effects of chemotherapy and radiotherapy.

With the exception of dental caries, L. acidophilus is non-pathogenic to humans. The bacteria combine with proteins that are found in saliva and food debris, forming plaque which digests sugary and other easily digestible foods and excretes acid. If enough acid is excreted in one area then calcium can be dissolved which in turn can remove some tooth enamel which will enable L. acidophilus to begin the process of tooth decay.

Lactobacillus acidophilus is also important in the fermentation of many foods, from dairy products to fruits and vegetables. Fermentation occurs when bacteria break down sugars and carbohydrates to produce alcohol, carbon dioxide and lactic acid . These by-products are responsible for the unique taste of fermented foods and help preserve and increase palatability.


There are many types of fermented dairy products that use L. acidophilus. The most familiar to Americans are sweet acidophilus milk and yogurt. Sweet acidophilus milk is consumed by individuals who suffer from lactose maldigestion and intolerance, a condition that effects approximately 75% of the worlds population. Maldigestion and intolerance occurs when enzymes (lactase) cannot break down lactose or milk sugar in the intestine. Failure to digest lactose results in discomfort, cramps and diarrhea. L. acidophilus is also used in the preparation of yogurt. L. acidophilus along with other lactic acid bacteria are added to milk to decrease the pH. When milk becomes acidic, proteins in the milk break down and coagulate to form a gel.

References:

http://www.aegis.com/pubs/gmhc/1993/gm071119.htmlhttp://www.elixa.com/nutrient/colonizer.htm
http://www.vitamins-nutrition.org/vitamins-guide/acidophilus-lactobacillus.html
http://www.garynull.com/Documents/Arthritis/Friendly_Bacteria.htm
http://www.lcusd.net/lchs/mewoldsen/dokko.html
http://dwb.unl.edu/Teacher/NSF/C11/C11Links/www.bact.wisc.edu/scienceed/lactobacillusacidophilus.html