Lactobacillus brevis is a species of lactic acid bacteria. It can be found in many different environments and in fermented foods such as sauerkraut and pickles. It is also one of the most common causes of beer spoilage. Ingestion has been shown to improve human immune function, and it has been patented several times. L. brevis is one of the major Lactobacillus species found in tibicos grains (aka water kefir grains), and has been identified as the species responsible for the production of the polysaccharide (dextran) that forms the grains. Major metabolites of L. brevis include lactic acid and ethanol. Strains of L. brevis and L. hilgardii have been found to produce the biogenic amines tyramine and phenylethylamine. Lactobacillus brevis is a species of lactic acid bacteria, all of which are Gram-positive, non spore forming organisms whose main metabolic pathway involves fermenting hexose sugars to produce lactic acid. The significance of all lactic acid bacteria throughout history up until today is their metabolism which is used for the preservations of foods and beverages. Despite a simple metabolic pathway, lactic acid bacteria play a prominent part in the world’s food supply and production of some beers and wine. Along with other lactic acid-producing bacteria, L. brevis plays an integral role in the fermentation of certain foods such as sauerkraut and pickles and is likewise the most common cause of spoiled beer. In fact, in Germany at one point, more than half of beer spoilage incidents were due to L. brevis alone. L. brevis can be isolated from the food sources in inhabits, one example being kimchi. The importance of L. brevis’ sequenced genome, is that integral proteins and enzymes can be isolated and used in experiment such as observing strains of hop-resistant lactic acid bacteria in beer spoilage or isolating decarboxylase DNA that can be cloned and inserted in other chromosomal DNA to encode novel proteins for that strain. Whole-genome sequencing was conducted at the U.S. Department of Energy for eight other species of Lactic acid bacteria. The method used was shotgun sequencing, where different parts of a genome are sequenced and then the pieces were assembled. The completed sequenced genome of L. brevis shows that this bacteria is circular and has one chromosome with a length of 2.3 Mbp containing 2185 proteins and 82 RNAs. Two plasmids are also sequenced, much smaller in length, and have 11 and 12 proteins. The evolution of Lactobacillales reveals a lot about the heritage of species and the ancestral gene losses, and may suggest where duplications and the addition of new and unique genes occurred. "Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats." One notable difference in L. brevis from the other species in this order, includes the loss of genes that carry out the biosynthesis of arginine and aromatic amino acids. Lactobacillus brevis and the Lactobacilli in general, are Gram-positive, rod-shaped, non spore forming bacteria arranged in singles. This implies a thick cell wall and an inner membrane in its rod shape. Although the sequenced genome of L. brevis is relatively small, the lactic acid bacteria can encode a multitude of different transporters to fulfill the needs of both prototrophic and auxotrophic strains. L. brevis bacteria are aerobe bacteria, they are motile, and probiotic. Fermentation is the one most common pathway in L. brevis and most other lactic acid bacteria. In this metabolic pathway, sugar (hexoses) is converted to lactic acid by the 6-phosphogluconate pathway, producing also CO2 and ethanol. Energy (ATP) is generated along the way by non-oxidative substrate level phoshorylation. The final product of fermentation, lactic acid contributes to production of such foods as cheese, yogurt, fermented milks and others by inhibiting the growth of other organisms and lowering the pH of the products. Along the pathway, many metabolic reactions occur, one of them being the breakdown of milk products for cheese production. L. brevis specifically is used in industrial production to act as a starter culture for several types of beer and sourdough bread. Lactobacillus brevis is mainly found in food. Environmentally, it can be found on dairy farms in raw milk, especially in bovine feces; however it rarely teams up with eukaryotes in a symbiotic way. Mostly it is found in proximity with other lactic acid bacteria, in a variety of foods. Most commonly these bacteria live in the food where they perform their metabolic pathways. Some major users of lactic acid bacteria include wine, salami, cheese, sourdough bread, pickles, yogurt, cocoa, and coffee. L. brevis specifically accommodates production of sour food. One of the most interesting interactions is that with the human intestinal flora. Lactobacillus, when ingested, has probiotic effects as it improves the immune system. Also, currently there are studies and research conducted on L. brevis and other lactic acid bacteria for incorporation into bio fuels and other environmental friendly and efficient materials. L. brevis is not a pathogen and there are no cases where it has caused or contributed to disease in humans. In fact, it is the other way around. This bacteria is probiotic, and improves the human immune system. L. brevis is hop-resistant, a compound that causes beer spoilage. This strain of bacteria is easy to study and research because its optimal growth conditions are known; fastest growth is at 30 degrees Celsius and at a pH of 4-6. Only a few strains of L. brevis are not resistant to hop compounds. Another source reveals that when DNA PCR analysis was conducted on Lactobacillus brevis strains found in breweries, a primer was isolated that can lead to distinguishing spoilage and non-spoilage strains of the lactic acid bacteria. This primer fragment was named hitA, and it can encode proteins that are responsible for a non-ATP binding membrane transporter which has been seen in both prokaryotic and eukaryotic species. In a hop bitter environment, the membrane is disintegrated due to a sensitive pH gradient, and H+ is exchanged for divalent cations, Mn2+ being an example. The experiment concluded that the hitA gene could be responsible for making products that are hop bitter resistant due to the introduction of metal ions which in essence destroys the intact proton gradient. 1. "Proteomic approach for characterization of hop-inducible proteins in Lactobacillus brevis" In order for lactic acid bacteria to cause beer spoilage during growth in beer, they must have a resistance to hops. A bacterial hop compound is also known as an ionophore which by definition is a small molecule whose main purpose is to transport ions through the lipid bilayer of a cell’s membrane. In the experiment, two strains of Lactobacillus brevis (TMW1.465 and variant TMW1.465A) were observed and the acid stress response and hop adaptation caused many detectable changes in the cells’ properties. To more clearly identify the cause of the changes in metabolism, membrane physiology, and cell wall composition, the scientists set up an experiment to identify related vital proteins despite the disadvantage of an incomplete genome sequence. Conclusively, hop resistance in the variant strain implied altered mechanisms that accounted for intracellular acidification, and changes in mechanisms that dealt with energy generation, genetic information, and enzyme functionality. Enzymes that are hop-regulated were also defined as being manganese or divalent cation dependent. Thus the ability to control the manganese level leads to the ability to tweak the metabolisms of applicable cells. One change found in metabolism in response to an environmental stress condition, was the shift into an energy-saving mode. Lastly this experiment demonstrated that bacteria in a hop stress environment were correlated with the depletion of proton motive force and with a limitation of the divalent cation, which as mentioned above is needed for hop-regulated enzymes. 2. "Cloning, sequencing and expression of a novel glutamate decarboxylase gene from a newly isolated lactic acid bacterium" A new strain of Lactobacillus brevis containing 84.292 mg/L/h of GABA (?-aminobutyric acid) was isolated from a Korean fermented food, Kimchi. Lactobacillus brevis OPK-3 was found to have a core fragment of glutamate decarboxylase (GAD) DNA and this fragment was then isolated, cloned, and amplified (by method of PCR) to end up with a full-length piece of core GAD DNA and enough data for a nucleotide sequence analysis. The scientists found the open reading frame (ORF) of the DNA contained 1401 bases and had the ability to encode 467 amino acids for protein assembly. The molecular weight was found to be 53.4 kDa. When compared to the amino acid sequence of other Lactic Acid Bacteria GAD DNA, Lactobacillus plantarum GAD, Lactococcus lactis GAD, and Listeria monocytogenes, the LbGAD ORF was 83%, 71%, and 60% identical, respectively. Further in the experiment, the LbGAD gene was introduced into an Escherichia coli strain (UT481), and when the transformed E. coli was tested, a 53.4 kDa protein was apparent, and the bacteria also had heightened GAD activity. 3. "Characterization of microflora in homemade semi-hard white Zlatar cheese" In this experiment, researchers observed changes in lactic acid bacteria and in the chemical composition of Zlatar cheese, over the course of 60 days during which it was ripening. This cheese was produced from only nonpasteurized cow’s milk without any bacterial aid. The results were very interesting; it was found that the while the number of lactobacilli was slowly increasing over the 60 days, the percentage of cocci first decreased, and then began increasing again at the 30 day mark, eventually catching up with lactobacilli. Also, it was found that out of all bacteria, 57 isolates showed antimicrobial activity and were decreasing with cheese age, until no more was detected in samples of 60 day old cheese. In doing replication - PCR analysis, Lactobacillus brevis was found to be one of the main species of bacteria present in addition to Lactobacillus paracasei, Lactococcus lactis, and Enterococcuus faecium. http://microbewiki.kenyon.edu/index.php/Lactobacillus_brevis
Lactobacillus acidophilus is one species in the genus Lactobacillus. It is sometimes used commercially together with Streptococcus salivarius and Lactobacillus delbrueckii ssp. bulgaricus in the production of acidophilus-type yogurt. Lactobacillus acidophilus gets its name from lacto- meaning milk, -bacillus meaning rod-like in shape, and acidophilus meaning acid-loving. This bacterium thrives in more acidic environments than most related microorganisms (pH 4-5 or lower) and grows best at 30°C (86 °F). L. acidophilus occurs naturally in the human and animal gastrointestinal tract, mouth, and vagina. L. acidophilus ferments lactose into lactic acid, like many (but not all) lactic acid bacteria. Certain related species (known as heterofermentive) also produce ethanol, carbon dioxide, and acetic acid this way. L. acidophilus itself (a homofermentative microorganism) produces only lactic acid. Like many bacteria, L. acidophilus can be killed by excess heat, moisture, or direct sunlight. Some strains of L. acidophilus may be considered a probiotic or "friendly" bacteria. Probiotic bacteria literally means "for life", meaning a probiotic bacteria aids human life. These types of healthy bacteria inhabit the intestines and vagina and protect against some unhealthy organisms. The breakdown of nutrients by L. acidophilus produces lactic acid, hydrogen peroxide, and other byproducts that make the environment hostile for undesired organisms. L. acidophilus also tends to consume the nutrients many other microorganisms depend on, thus outcompeting possibly harmful bacteria in the digestive tract. During digestion, L. acidophilus also assists in the production of niacin, folic acid, and pyridoxine. L. acidophilus can assist in bile deconjugation, separating amino acids from bile acids, which can then be recycled by the body. Some research has indicated L. acidophilus may provide additional health benefits, including improved gastrointestinal function, a boosted immune system, and a decrease in the frequency of vaginal yeast infections. Some people report L. acidophilus provides relief from indigestion and diarrhea.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, which occurs when enzymes (lactase) cannot break down lactose or milk sugar in the intestine. Failure to digest lactose results in discomfort, cramps and diarrhea. A University of Nebraska study found that feed supplemented with L. acidophilus and fed to cattle resulted in a 61% reduction of Escherichia coli 0157:H7. Research has indicated L. acidophilus may be helpful reducing serum cholesterol levels. L. acidophilus is part of the normal vaginal flora. The acid produced by L. acidophilus in the vagina helps to control the growth of the fungus Candida albicans, helping to prevent vaginal yeast infections. The same beneficial effect has been observed in cases of oral or gastrointestinal Candidiasis infections. Certain spermicides and contraceptive creams can kill L. acidophilus in the vagina, clearing the path to possible yeast infections. Antibiotics taken orally will also kill beneficial bacteria, including L. acidophilus. After a therapy that includes antibiotics, patients are occasionally instructed to take an L. acidophilus treatment in order to recolonize the gastrointestinal tract. To that effect, L. acidophilus is often sold in health stores in pill or powder form as a nutritional supplement. A part of the claims in favor of such treatment refer to attaining a better digestion thanks to a recovered normal intestinal flora, the ensuing reduction of constipation, while others indicate a link between L. acidophilus and a possible decrease in the incidence of certain diseases, including yeast infections in the upper digestive tract (especially those caused by Candida albicans), other gastrointestinal disorders, and a weakened immune system. However, despite popular belief, most researchers agree that the present knowledge on the nutritional benefits of taking L. acidophilus supplements is inconsistent and inconclusive, and that further study is needed before substantiating many of these claims. Lactobacilli are bacteria that normally live in the human small intestine and vagina. Lactobacillus acidophilus is generally considered to be beneficial because it produces vitamin K, lactase, and anti-microbial substances such as acidolin, acidolphilin, lactocidin, and bacteriocin. Multiple human trials report benefits of Lactobacillus acidophilus for bacterial vaginosis. Other medicinal uses of Lactobacillus acidophilus are not sufficiently studied to form clear conclusions. The term "probiotic" is used to describe organisms that are used medicinally, including bacteria such as Lactobacillus acidophilus and yeast such as Saccharomyces boulardii . Although generally believed to be safe with few side effects, Lactobacillus acidophilus taken by mouth should be avoided in people with intestinal damage, a weakened immune system, or with overgrowth of intestinal bacteria. http://www.mayoclinic.com/health/lactobacillus/NS_patient-acidophilus There are an estimated several trillion friendly bacteria comprising over 400 species in the average human gastrointestinal tract. By body weight, each of us carries around nearly four pounds of intestinal microflora. While Lactobacillus Acidophilus is probably the most well known of these, others you should know about include Bifidobacterium bifidum and B. longum. When the intestines are healthy, there are more friendly bacteria than nfriendly, or pathogenic ones; you might think of this arrangement as a kind of microbial ecology in which species have their allotted role and population density in the intestinal environment. Lactobacillus Acidophilus is the predominant friendly bacteria in the upper intestinal tract. Lactobacillus is the general (genus) name of the bacteria, Acidophilus is the particular strain. It helps reduce the levels of harmful bacteria and yeasts in the small intestine and also produces lactase, an enzyme which is important in the digestion of milk. L. Acidophilus is also involved in the production of B vitamins (niacin, folic acid, and pyridoxine) during the digestive process. Not only can Acidophilus and other probiotics tune up your intestinal function, counteract antibiotic damage, and stimulate the immune system to function better when you?re relatively well, but when you?re ill, they can also contribute significantly to relief of health problems ranging from indigestion and diarrhea to colon and liver cancer. Acidophilus, used in milk in grocery stores and also sold in concentrated form as a health-food product, consists of billions of live, beneficial bacteria, taken to change the flora of the digestive system and help crowd out harmful organisms. Most physicians do not take acidophilus very seriously, but regard it as a health food and do not mention it to their patients; you will probably not hear about it from your doctor. But some physicians do recommend it for their AIDS patients, and recently we have been hearing of a number of persons who are convinced that it has helped them in controlling diarrhea and/or candida (thrush) in the digestive tract. "We (AIDS.ORG) don't know of any scientific studies which would prove or disprove these uses; but acidophilus is readily available, inexpensive, easy to use, and evidently helpful to some. It appears to be entirely harmless, but patients should check with their physicians to make sure there are no reasons to avoid trying it." The characteristics required of lactobacilli as probioties are the following: Beneficial function Easy cultivation Nonpathogenicity Adhesion and Population stability. Several studies have assessed the potential of lactobacilli in the prevention or treatment of certain genitourinary tract infections such as bacterial vaginosis, vaginitis, or urinary tract infections. The main goal of therapy with biotherapeutic agents should be to prevent overgrowth of a pathogen until such a time that the normal microbiota can be reestablished. The possibility of using lactobacilli is promising, especially in pregnant women and in the case of patients with recurrent genitourinary tract infections produced by strains with resistance to several antibiotics. In addition, probiotic therapy is considered as "natural" and without side effects in contrast with conventional pharmaceutical treatments, but there is a limited array of tested biotherapeutic agents and a lack of pharmacokinetic data. The authors have tested the therapeutic efficacy of a multibacterial combination consisting of Lactobacillus acidophilus and Bifidobacterium bifidum in elderly patients with bowel disorders. Bacteriological and histopathologic investigation showed this combination to yield excellent biologic results with restoration of duodenal bacterial flora and subsidence of clinical symptoms. The function of the muciparous glands was restored and the duodenal mucosa was normalized. http://www.diet-and-health.net/Supplements/Acidophilus.html
Originally classified in the 1930s as Group D Streptococci, Enterococci were officially given genus status in 1984 after hybridization studies showed a more distant relationship to Streptococci. Enterococci are gram-positive, spherical bacteria that colonize in groups or chains. They are naturally found as part of the digestive tract flora in many organisms, including humans. They are robust microbes able to tolerate relatively high salt and acid concentrations. They also seem to be able to withstand low levels of detergents, explaining why inadequate cleaning procedures can promote Enterococcus infections. What is now recognized as pathogenic Enterococcus was studied as early as the late 1900s. Currently, Enterococcus infections account for 12% of all nosocomial infections, second only to E. coli. An Enterococcus infection can cause complicated abdominal infections, skin and skin structure infections, urinary tract infections and infections of the blood stream. These infections can be difficult to treat, particularly in cases where the strain involved has developed resistance to several antibiotics. Infection can be life threatening in such instances, especially if the patient is already immunodeficient. There are two species of Enterococci which cause the symptoms described above, E. faecalis, which accounts for the majority of infections (79%), and E. faecium. In a study conducted between 1995 and 1997, data were collected from over 15,000 Enterococcus isolates. Of those, less than 2% of E. faecalis were found to be resistant to ampicillin and vancomycin, whereas 83% of the E. faecium isolates were resistant to ampicillin and 52% were resistant to vancomycin. E. faecium is known to have a resistance to several types of antibiotics including quinolones and aminoglycosides. Resistance to penicillin was first observed in E. faecium in 1983, and in 1988 the first cases of resistance to the "antibiotic of last resort", vancomycin, were detected in Europe. Vancomycin-resistant strains of E. faecium were reported in the US in 1989. Resistance to several antibiotics and tolerance for adverse conditions makes E. faecium a major concern for the medical community, which has dubbed this microbe a "supergerm". http://www.jgi.doe.gov/News/Efacium_overvw.htm Description and significance E. faecium is a human pathogen that causes nosocomial bacteremia, surgical wound infection, endocarditis, and urinary tract infections. Nosocomial infections are those acquired in medical setting during treatment of a prior complaint. The normal habitat includes the gastrointestinal tract of a multitude of animals but it can also be found in the oral cavity and vaginal tract. The microbe can survive for long periods of time in soil, sewage, and inside hospitals on a variety of surfaces. It can grow in temperatures ranging from 10 to 45 degrees Celsius, in basic or acidic environments, and in environments which are isotonic or hypertonic. E. faecium is a Gram-positive, spherical cell that can occur in pairs or chains. The colonies formed are 1-2 mm in length and appear wet. The cells are non-motile. E. faecium can be highly drug resistant and acquires its drug resistance by plasmids and conjugative transposons as well as chromosomal genes that encode resistance. Some strains have become resistant to vancomycin, penicillin, gentamicin, tetracycline, erythromycin and teicoplanin. Spread of the disease occurs between patients in hospitals due to transfer of the pathogen by hands or medical instruments. Also antibiotic use can decrease the number of other intestinal bacteria that are susceptible to the antibiotic and decrease competition for the drug resistant E. faecium. E. faecium was known as Streptococcus faecium until its name changed in 1984 due to a re-categorization. Genome structure The Joint Genome Institute in collaboration with Dr. Barbara Murray sequenced the genome of E. faecium in one day. It has an estimated size of 2.8 Mbp. The genome project is still under construction and has not been fully analyzed. E. faecalis is a close relative of E. faecium and its genome has been sequenced and analyzed. The sequencing of a vacomycin resistant E. faecalis strain, Enterococcus facalis V583, revealed 1 circular chromosome and 3 plasmids. The chromosome consists of 3218031 base pairs and each plasmid, pTEF1, pTEF2, pTEF3, consists of 66320, 57660, and 17963 base pairs respectively. Two of the plasmids are pheromone-sensing conjugative plasmids. Also found was a mobile conjugative transposon that encodes vacomycin resistance. Over a quarter of E. feacalis’ 3337 open reading frames are mobile and/or exogenously acquired DNA. These mobile and/or exogenously acquired DNA include seven integrated phage regions, 38 insertion elements, conjugative and composite transposons, a patheogenicity island, and integrated plasma genes. Its ability to acquire outside DNA contributes to E. faecalis’ multiple drug resistance. The genes encoding vacomycin resistance in E. faecalis’ are similar to E. faecalis’ vanB vancomycin-resistance conjugative transposon Tn1549 and were probably transferred as a cassette by lateral gene transfer. Cell structure and metabolism Cell Structure E. faecium is a gram-positive bacterium. Gram-positive cells have a thick peptidogycan layer along with teichoic and lipoteichoic acids. It has circular DNA as well as several plasmids. It is capable of conjugation through the release of sex pheromones and secretes aggregation substances and also forms bioflims. The cell has pili and flagella. Metabolism E. faecium lacks the Krebs’s cycle and respiratory chain and therefore it gains energy through fermentation. It is a facultative anaerobe which means it can make ATP by aerobic respiration if oxygen is present but will utilize fermentation if no oxygen is present. Ecology E. faecium can acquire drug resistance through three types of conjugation: pheromone-responsive plasmids, broad host-range plasmids, and conjugative transposons. Pheromone response plasmid occurs when the cell secretes a sex pheromone for a specific plasmid. When a donor cell comes into contact with the pheromone, transcription of the relevant portion of the plasmid is turned on and it also secretes a sticky substance. The sticky or aggregation substance facilitates the transfer of the plasmid to the recipient cell by helping them to stick together. Transfer of other plasmids can also occur between different genera of bacteria including staphylococci, and streptococci. The consequence of the ability of E. faecium to acquire broad host-range plasmids is that drug resistance can be widely and more easily spread. Conjugative transposons can also transfer antibiotic resistance between genera as well as between gram-positive and gram-negative bacteria because they do not need to cooperate with host machinery in order to insert themselves into a plasmid or chromosome of the bacterium. E. faecium can interact with other bacteria to spread drug resistance through conjugation. Pathology E. faecium is considered a super-bug. It can colonize many organs of the body including the gastrointestinal tract and the skin, and can also survive for long periods on inanimate objects. This along with its multi-drug resistant characteristics makes it a particularly nasty pathogen. Contributing to the virulence of E. faecium is the enterococcal surface protein (Esp). This protein allows the bacteria to aggregate and form bioflims. Strains with the Esp gene are normally found in clinical isolates and not found in strains that colonize the gut. Bioflim formation allows colonization of tubing used in hospitals and can lead to infections of the blood as well as urinary tract infections. Esp gene expression increased under increased temperature as well as a change to anaerobic condition. The regulation of the Esp gene in this way allows E. faecium to change its response when it enters a host. Additional virulence factors include aggregation substance (AS), cytosolin, and gelantinase. AS allows the microbe to bind to target cells and it facilitates the transfer of genetic material between cells. Cytosolin is a protein found in the cytosol and lyses erythrocytes. GeIE can hydrolyze peptides. The presence of virulence factors differ among strains and usually are specific for the host the strain colonizes. Application to Biotechnology E. faecium produces antibacterial peptides called bacteriocins. This microbe can be used in fermenting foods such as cheese and vegetables. It is introduced to the starting cultures to inhibit growth of unwanted microbes. E. faecium can also be used as a probiotic to out-compete deleterious bacteria in the gastrointestinal tract. Current Research A study showed that the metabolism of E. faecium can cause eukaryotic cell DNA damage through its metabolism. Through the autoxidation of membrane bound demethylmenaquinone E. faecium produces superoxide, hydrogen peroxide, and hydroxyl radicals. These oxidants can produce chromosomal instability that can cause polyps and colon cancer. Hydrogen peroxide derived from E. faecium was shown to damage luminal cells in the colon of rats, demonstrating E. faecium’s potential carcinogenic property. As vacomycin resistance increases in E. faecium, health care providers must find novel strategies for treating patients affected by the microbe. Often doctors must venture into uncharted territories to save a patient. In one example a premature infant in a neonatal unit was diagnosed with a vacomycin resistant strain that had infected her central nervous system through a ventriculoperitoneal (VP) shunt. Through laboratory testing it was found that the germ was susceptible to linezolid. As published data of treatment of central nervous system infections with linezolid in infants was unavailable the hospital dosed the infant using the resources at hand. As E. faecium continues to acquire drug resistance novel strategies are needed to combat it. The use of antibiotics in animal feed has caused an increase in resistance to antibiotics. The van A gene began presenting itself outside of hospitals as a result of selective pressure due to antibiotic use. The van A gene was spread through conjugation. Studies have shown that the use of virginiamycin in stock animals produced drug resistant enterococci. http://microbewiki.kenyon.edu/index.php/Enterococcus_faecium
Bifidobacteria are anaerobic, gram-positive, irregular or branched rod-shaped bacteria that are commonly found in the intestines of humans and most animals and insects. They were first isolated and described over one hundred years ago from human feces and were quickly associated with a healthy GI tract due to their numerical dominance in breast fed infants compared to bottle fed infants (Tissier, 1899; 1906). While they were first grouped in the genus Bacillus, the genus Bifidobacterium was proposed in the 1920’s (Orla-Jensen, 1924). However, there was not a taxonomic consensus for this new genus and for much of the 20th century, they were classified in the genus Lactobacillus, due to their rod-like shapes and obligate fermentative characteristics. However, the accumulation of studies detailing DNA hybridizations, GC content and unique metabolic capabilities resulted in the resurrection of the Bifidobacterium genus, which was included in the eight edition of Bergey’s manual in 1974. They are characterized by a unique hexose metabolism that occurs via a phosphoketolase pathway often termed the ‘bifid shunt’. Fructose-6-phosphate phosphoketolase (F6PPK) is a key enzyme of the ‘bifid shunt’ and its presence is the most common diagnostic test for this genus, as it is not present in other gram-positive intestinal bacteria. The genus is comprised of 31 characterized species, 11 of which have been detected in human feces (Tannock, 1999). B. longum is often the dominant species detected in humans and is the only species to regularly harbor plasmids. It is a leading member of the probiotic bacteria due to numerous studies that have provided a growing body of evidence for its role in a myriad of potential health benefits. These include diarrhea prevention in antibiotic treated patients (Black et al., 1991); cholesterol reduction (Dambekodi and Gilliland, 1998); alleviation of lactose intolerance symptoms (Jiang et al., 1996); immune stimulation (Takahashi et al., 1998); and cancer prevention (Reddy and Rivenson, 1993). This myriad of potential health benefits attributed to the B. longum species clearly illustrates that this species possesses many very interesting characteristics. The potential cancer prevention ability is very interesting and studies have suggested this may be due to the protection from different carcinogens, including methyl quinolines (Reddy and Rivenson, 1993), heterocyclic amines (Sreekumar and Hosono, 1998), nitrosamines (Grill et al., 1995), and azomethane (Singh et al., 1997). It is anticipated that identification and functional analysis of the genetic determinants involved in these activities will strengthen the evidence for the involvement of B. longum in these significant health benefits. Selection of suitable strains for probiotic purposes is very difficult as inherent characteristics of strains of B. longum that are necessary for its survival and competition in the human large intestine are currently very poorly understood (O’Sullivan, 2001). The use of the sequenced genome in microarray analysis should reveal the pertinent traits that are important for these bacteria to attain dominance in these complex ecosystems. http://genome.jgi-psf.org/draft_microbes/biflo/biflo.home.html Bifidobacterium longum keeps the human digestive system running smoothly One of the most important residents in the human gastrointestinal tract, B. longum keeps the digestive system running smoothly, blocks the growth of harmful bacteria, and boosts the immune system. The organism ferments sugars into lactic acid and has many health benefits for humans and is often the dominant bacterium found in humans. It is a Gram-positive, anaerobic, branched rod-shaped bacterium. Researchers have identified a number of proteins that are specialised to help B. longum interact with the human host and persist against harmful bacteria and future reseach will now closely look at which genes allow B. longum to live in different environments such as dairy products, vegetables and the human gastrointestinal tract. Bifidobacterium longum is among the first to colonise the sterile digestive tract of newborns and predominates in breast-fed infants. Formula-fed infants have a different microflora, and this may be related to the higher risk of diarrhea and allergies in these babies. Recognising the many benefits to good health, lactic acid bacteria are included in dairy foods and taken as supplements in powder, liquid extracts, or tablets and this has also resulted in people supplementing their diets with these microbes, which are also called probiotics (meaning 'in favour of life'). Live cultures in yogurt have been used as a remedy for hundreds of years to support immune function and doctors recommend bacterial supplements to patients who take antibiotics, suffer from bacterial, viral or fungal infections or have various digestive problems. Other potential uses of B. longum are being investigated in separate studies. Japanese researchers showed that the microbe might be useful as a gene delivery vector for cancer therapy. They injected the bacterium into the tail veins of rats and demonstrated that B. longum is accumulated in the tumor. Comparative studies of lactic acid bacteria may lead to better understanding the microbes' roles in food fermentation and human health. http://www.ebi.ac.uk/2can/genomes/bacteria/Bifidobacterium_longum.html
Design and Duration: Randomized, double-blind, placebo-controlled trial for eight weeks, preceded by a 4-week run-in period and followed by a 4-week washout period to assess symptoms post-treatment. Participants: 75 volunteers, ages 18-73 years (average 44.3 years) who fit the Rome II criteria for irritable bowel syndrome (IBS)--diagnosis based on the presence for 12 weeks (not necessarily consecutive) during the past year of abdominal discomfort or pain and two out of three of the following symptoms: relieved with defecation, onset associated with a change in frequency of stool, and onset associated with a change in stool appearance. Symptoms that cumulatively support the diagnosis of IBS are [less than or equal to]3 bowel, movements per week; >3 bowel movements per day; hard or lumpy stools; loose or watery stools; straining during defecation; urgency; incomplete evacuation of bowels; mucus in stools; and a sensation of abdominal fullness, bloating or swelling. Subclassification of IBS determined that 28% were diarrhea predominant, 26% constipation dominant, and 45% alternated between constipation and diarrhea. Twenty-five percent were smokers, and 88% drank alcohol. Inflammatory bowel disease (IBD) and other organic gastrointestinal diseases were ruled out, as were "significant systemic diseases." Excluded from the study were pregnant women; people with lactose intolerance or immunodeficiency; and previous abdominal surgery, except for hernia repair and appendectomy. Study Medication and Dosage: Volunteers were randomized to receive 1 X [10.sup.10] cfu (colony forming units) of Lactobacillus salivarius subspecies salivarius UCC4331 or Bifidobacterium infantis 35624 in a malted milk drink or placebo q.d. Probiotic species were originally isolated from the ileocolic region of an adult human; were nonpathogenic; were resistant to intestinal acid and bile; and demonstrated the ability to adhere to epithelial cells, to transiently colonize the human gastrointestinal tract, and to be metabolically active. Outcome Measures: IBS symptoms were assessed based on volunteer diary cards, which were collected at weekly appointments. Three categories of symptoms were evaluated--abdominal pain or discomfort, bloating or distension, and bowel movement difficulty or urgency--using a 7-point ordinal scale (Likert scale*) and a 10-point visual analog scale (VAS). Changes in quality of life were determined at baseline and at the end of the treatment washout periods by a questionnaire that asked about dysphoria, interference with activity, body image, health worry, food avoidance, social reaction, sexual function, and relationship impact. Hematology (CBC, blood chemistry) and quantitative immunoglobulins were tested at the initial evaluation and the conclusion of the study. Stool and peripheral blood samples were collected at the time of randomization and after treatment and analyzed for fecal flora analysis and interleukin 10 (IL-10) and IL-12p40 cytokine levels, respectively. Key Findings: The composite Likert score was significantly lower for those treated with B. infantis 35624 compared to placebo (p<0.05) p="0.05)." p="0.003)." p="0.001)," href="http://findarticles.com/p/articles/mi_m0FDL/is_3_12/ai_n17211120/pg_3?tag=content;col1">http://findarticles.com/p/articles/mi_m0FDL/is_3_12/ai_n17211120/pg_3?tag=content;col1 Bifidobacterium is among the friendly microorganisms that have been shown to alleviate symptoms of inflammatory bowel disease. Antibiotics disrupt the balance of natural intestinal flora. The use of probiotics such as Lactobacillus, Streptococcus, and Bifidobacterium restores the population of beneficial bacteria. At birth a baby's gastrointestinal tract is sterile. The baby gets its first taste of bacteria while moving through the birthing canal and through breast milk. Lactobacilli and Bifidobacteria maintain a healthy balance of intestinal flora by producing organic compounds. These organic compounds include lactic acid, hydrogen peroxide, and acetic acid that increase the acidity of the intestine and curb the reproduction of many harmful bacteria. Dietary supplementation of Bifidobacterium bifidum encourages resistance to intestinal infections. It has resulted in synthesis of B-complex vitamins and absorption of calcium. Bifidobacterium bifidum also helps improve symptoms of diarrhea and constipation. Bifidobacterium infantis is found in the intestines of infants and adults. It is also present in the vaginal tract. This probiotic bacterium is a specific inhabitant of the large intestine where it can be found in high concentration among infants. This species of Bifidobacterium is predominant in the feces of breast-fed infants. Like other Bifidobacteria species, this organism can produce acids that may retard the colonization of certain foreign or harmful bacteria in the colon. Research suggests that the presence of Bifidobacterium infantis in the colon helps reduce the incidence of infantile diarrhea. Common synonyms for this species are Bifidobacterium lactentis, Bifidobacterium liberorum, and Actinomyces parabifidus. Try Växa's Homeopathic Medicinal ReFlora+ that contains a special complex of 10 different beneficial bacteria and other nutrients, to help the body restore healthy bacterial flora. The ingredients in this homeopathic formula have been shown to: Help destroy putrefactive bacteria (the "bad" bacteria) within the lower tract Help remove toxins from the lower tract and disable possibly carcinogenic bacteria Help normalize intestinal pH Help repair damage to the digestive tract http://www.vaxa.com/bifidobacterium.cfm
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