Everyone has a personal microbial fingerprint. Our blend of bacterial flora is constant over time. Bacterial cells make up most of the material in the colon and 60% of the mass of faeces. Somewhere between 300 and 1000 different species live in the gut, with most estimates at about 500. However, it is probable that 99% of the bacteria come from about 30 or 40 species.

One group of gram-positive, non-sporing bacteria that carry out a lactic acid fermentation of sugars. So called, Lactic Acid Bacteria [LAB], the group includes species of Lactobacillus, Leuconostoc, Pediococcus and Streptococcus .They are vitally important group interacting directly through areas in the gut called Pyers patches to produce components of our immune system

Accompanying image

We host other would be pathogenic bacteria, the numbers of which are controlled by healthy amounts of none pathogenic commensal flora. These commensal organisms do not of course present to the immune system as a pathogenic foreign body [antigen] the amazing thing is although they avoid a full blown immune response they do interact through pyers patches to produce lymphocyte's including very special cross reactive antibodies.

The commensal microorganisms in the human gut are important to our well-being. Their metabolic capacity has been compared to that of the liver—much of it aiding digestion. They are regarded as self by the immune system, our commensal flora manipulate the immune system. This latest piece of information details how genetic material is exchanged between microbes and humans..just to make the point again it shows that we have evolved with our microbes they are precious , they play an essential role in our health as in all higher animals. To replace antibiotic depleted flora is the key to health [probiotic bacteria that are hyped as the answer do not permanently restore gut flora]..This author believes he has the know how to restore gut flora permanently.

All life is one

horizontal gene transfer demonstrates why we shouldnt be creating with genetic engineering what are in effect new life forms ,there are no safeguards inappropriate genes will contaminate other life forms with unknown consequences.

Horizontal gene transfer (HGT), also lateral gene transfer (LGT), is any process in which an organism incorporates genetic material from another organism without being the offspring of that organism. By contrast, vertical transfer occurs when an organism receives genetic material from its ancestor, e.g., its parent or a species from which it has evolved.

Taking the gonococcus-human relationship to a whole new level: implications for the coevolution of microbes and humans.

Shafer WM, Ohneck EA.

Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA. wshafer@emory.edu

Abstract

While horizontal gene transfer occurs frequently among bacterial species, evidence for the transfer of DNA from host to microbe is exceptionally rare. However, the recent report by Anderson and Seifert [mBio 2(1):e00005-11, 2011] provides evidence for such an event with the finding that 11% of Neisseria gonorrhoeae strains harbor a 685-bp sequence that is 98 to 100% identical to the human long interspersed nuclear element L1. While the function of this element in gonococci remains unclear, this finding significantly impacts our consideration of the coevolution of hosts and microbes, particularly that of humans and pathogens.

PMID: 21521723 [PubMed - indexed for MEDLINE]
PMCID: PMC3087451

Opportunity and means: horizontal gene transfer from the human host to a bacterial pathogen.

Anderson MT, Seifert HS.
Source
Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.
Abstract
The acquisition and incorporation of genetic material between nonmating species, or horizontal gene transfer (HGT), has been frequently described for phylogenetically related organisms, but far less evidence exists for HGT between highly divergent organisms. Here we report the identification and characterization of a horizontally transferred fragment of the human long interspersed nuclear element L1 to the genome of the strictly human pathogen Neisseria gonorrhoeae. A 685-bp sequence exhibiting 98 to 100% identity to copies of the human L1 element was identified adjacent to the irg4 gene in some N. gonorrhoeae genomes. The L1 fragment was observed in ~11% of the N. gonorrhoeae population sampled but was not detected in Neisseria meningitidis or commensal Neisseria isolates. In addition, N. gonorrhoeae transcripts containing the L1 sequence were detected by reverse transcription-PCR, indicating that an L1-derived gene product may be produced. The high degree of identity between human and gonococcal L1 sequences, together with the absence of L1 sequences from related Neisseria species, indicates that this HGT event occurred relatively recently in evolutionary history. The identification of L1 sequences in N. gonorrhoeae demonstrates that HGT can occur between a mammalian host and a resident bacterium, which has important implications for the coevolution of both humans and their associated microorganisms.

Copyright © 2011 Anderson and Seifert.

Comment in
MBio. 2011;2(3):e00067-11.
PMID: 21325040 [PubMed - indexed for MEDLINE] PMCID: PMC3042738

Dr. Francis Crick Nobel prize-winner and the co-founder of the shape of the DNA molecule

-- claimed an advanced civilization transported the seeds of life to Earth .He came to that conclusion after realising that there was not enough time to produce the tremendous diversity of life on Earth . Horizontal gene transfer explains that expansion in life forms. We should be using the metaphor the “mosaic of life” not “tree of life”

This news published in the journal Nature [March 2010] backs up my findings on the [ignored] importance of normal gut flora and health ..All the researchers need to do now is throw antibiotics into the equation and perhaps the world will be alerted to the carnage they have caused ..It's interesting that the researchers assume gut flora is altered as a result of infection and not visa versa-- illness [infections] as a result of altered gut flora ..

Human gut microbes hold 'second genome'

extract

"Gut flora is crucial for our health. We're basically living in symbiosis with these microbes.

"The bacteria help digest food, provide vitamins, protect us from invading pathogens. If there's a disturbance, people get all sorts of diseases such as Crohn's disease, Ulcerative colitis, and a link has also been made to obesity."
“"The article is extremely timely given the escalating interest in the influence of the gut microbiota in many aspects of health ranging from Irritable Bowel Disease, sepsis and obesity to autism,"

http://news.bbc.co.uk/1/hi/sci/tech/8547454.stm

September 2008 ..Breakthrough.... we now know “How Friendly Bacteria Avoids Immune Attack To Live Happily In The Gut”..

The implications are immence… For a long time scientists have been puzzled by the fact that the immune system in the gut is capable of fighting toxic bacterial infection while staying, at the same time, tolerant to its resident "friendly" bacteria. But an article now published in the journal Cell Host & Microbe1 is starting to open the door to this mystery by revealing how a recently discovered gene pims is activated by the gut immune response against friendly bacteria to rapidly suppress it, effectively creating tolerance to the gut microbiota.

http://www.medicalnewstoday.com/releases/120029.php

The incidences of autism itself like that of other conditions, learning disabilities, attention deficit hyperactivity disorder (ADHD), asthma, diabetes,
arthritis, chronic fatigue syndrome, inflammatory bowel disease and other autoimmune and neurological disorders, has risen dramatically in the
U.S. and other technologically advanced countries.

Prof Mark Woolhouse, Chair of Infectious Disease Epidemiology at Edinburgh University says humans risk being overrun by
diseases from the animal world, according to researchers who have documented 38 illnesses that have made that
jump over the past 25 years.

Each year for the last 25 years, one or two new pathogens and multiple variations of existing threats have infected
humans for the first time. Without speculating about earlier infection rates, Woolhouse told reporters it appears
impossible the human species could endured such a rapid pace of new infections over thousands of years "Humans have always been
attacked by novel pathogens. This process has been going on for millennia. But it does seem to be happening very fast in these modern
times,

Prof Woolhouse argues that both many of those diseases and other afflictions will not persist in humans or that there is something peculiar today allowing so many of them to take root in humans.

Autoimmune disorders in the parents of autistic children are much more frequent than in parents of non-autistic children. Many thousands display
symptoms of a yeast infection. The western world is also experiencing an explosive growth of Lyme disease and there is a correlation.

THE BENEFITS OF THE NORMAL FLORA

Gut Psychology Overlap

Scientists have found evidence of what many of us already suspected: our brains and our guts "talk" to each other. In fact they are so intimately connected that some believe the gut and the brain should be viewed as part of one system.

The nature of the interactions between an animal host and its normal flora has been inferred from the study of germ-free animals (animals which lack any bacterial flora) compared to conventional animals (animals which have a typical normal flora). Following are the primary beneficial effects of the normal flora that are derived from these studies.

Read article ’’Gut Bacteria Play Key Role in Immune System at Autism is an infectious disease page

1. The normal flora synthesize and excrete vitamins in excess of their own needs, which can be absorbed as nutrients by the host. For example, enteric bacteria secrete Vitamin K and Vitamin B12, and lactic acid bacteria produce certain B-vitamins. Germ-free animals may be deficient in Vitamin K to the extent that it is necessary to supplement their diets.

2. The normal flora prevent colonization by pathogens by competing for attachment sites or for essential nutrients. This is thought to be their most important beneficial effect, which has been demonstrated in the oral cavity, the intestine, the skin, and the vaginal epithelium. In some experiments, 10 Salmonella bacteria can infect germ-free animals, while the infectious dose for conventional animals is near 10,000,000 cells.

3. The normal flora may antagonize [block] other bacteria through the production of substances, which inhibit or kill none-indigenous species. The intestinal bacteria produce a variety of substances ranging from relatively none-specific fatty acids and peroxides to highly specific bacteriocins, which inhibit or kill other bacteria.

4. The normal flora stimulate the development of certain tissues, i.e., the caecum and certain lymphatic tissues (Peyer's patches) in the GI tract. The caecum of germ-free animals is enlarged, thin-walled, and fluid-filled, compared to that organ in conventional animals. Also, based on the ability to undergo immunologic stimulation, the intestinal lymphatic tissues of germ-free animals are poorly developed compared to conventional animals.

5. The normal flora stimulate the production of cross-reactive antibodies. Since the normal flora behaves as [none-pathogenic] antigens in an animal, they induce an immunologic response, in particular, an antibody-mediated immune (AMI) response. Low levels of antibodies produced against components of the normal flora are known to cross react with certain related pathogens, and thereby prevent infection or invasion. Antibodies produced against antigenic components of the normal flora are sometimes referred to as "natural" antibodies, and such antibodies are lacking in germ-free animals.