You are in Guest mode. If you want to post, you'll need to register (we promise it's painless).
Registered users should log in now. (Forgot your password?)

Guest-accessible forum This forum allows unregistered guests access to read. You must register to post in this forum.

Nature_and_Environment.123

Topic HomeTopicsForum HomeForumsHomeSearchSettingsHelpExit

Bacteria - the essential form of life

--------

{Nature_and_Environment.123.1}: Jay Hoffman {resist} Mon, 16 Dec 2019 21:10:03 CST (23 lines)

Bacteria - the essential form of life
by Pablo Pomposiello, Love bacteria and viruses

Most life on Earth is bacterial.

Bacteria do most of the photosynthesis on Earth.

Bacteria produced in the past most of the oxygen in the atmosphere,
allowing the evolution of aerobic organisms, this is, all macroscopic
life forms.

Bacteria do a large part of nitrification, or turning atmospheric
nitrogen into nitrates in the soil, where it can be used by plants.

Bacteria are decomposers in the soil, sediments and water, breaking
down macromolecules into useful smaller molecules that can be used by
other organisms.

90% of cells in the human body are bacterial cells.

Bacteria are probably the most important domain of life as they
heavily influence ecosystem processes.
etc., etc.

--------

{Nature_and_Environment.123.2}: Jay Hoffman {resist} Mon, 16 Dec 2019 21:11:11 CST (85 lines)

“But as long as humans can’t live without carbon, nitrogen, protection
from disease and the ability to fully digest their food, they can’t
live without bacteria,”— Anne Maczulak, famous microbiologist.

Bacteria – a word that often brings out a sense of uneasiness in most
of us are, in fact, one of the earliest forms of life. It can be quite
unnerving to know that there are bacteria all over your skin, hair,
and even inside the body. But only a few species of bacteria are
dangerous. The majority of bacteria are good, and without them, life
on earth wouldn’t be possible.

Bacteria and our Environment

Efficient Recyclers: Bacteria play a critical role in the
decomposition of organic matter in soil and in the oceans. It also
cycles chemical elements such as carbon and nitrogen, which are
essential for humans to survive.

Creator of Amino & Nucleic Acids: Soil bacteria cyanobacteria play a
crucial role in turning atmospheric nitrogen into ammonium or nitrates
that plants can absorb to create amino acids and nucleic acids, the
building blocks of DNA. We just eat the plants and get all the
benefits.

Nutrient Builders: Bacteria constantly helps maintain the cycle of our
nature. The major constituent of soil is bacteria. They play a very
crucial role in building nutrients, i.e. recycling carbon, nitrogen,
sulphur and phosphorus between human beings and the environment.
Without these cycles, there would be no exchange of elements, which
are the backbone of proteins, sugars, and fats.

Water Recyclers: Recently, scientists have found evidence that
bacteria represent many particles that cause clouds to precipitate
into falling snow and rain.

Harvesting Agents: Nitrogen-fixing bacteria like Azotobacter,
Clostridium, etc. fix free nitrogen of the soil and make it available
to the plants, which is a necessity for the survival of the plants.
And this is how bacteria help us in harvesting vegetation.

Pollution fighters: Heavy metals from industry and toxic synthetic
organic chemicals, pose serious environmental and health risks.
Bioremediation uses certain bacteria that digest toxic substances and
convert them into less harmful substances. Also, the traditional
chemical analyses for determining and locating toxic waste are
expensive and inaccurate. Therefore, scientists have designed
biosensors, which are genetically modified bacteria that can locate
pollutants.

Humans and Bacteria

The number of bacterial cells in the body is commonly estimated at 10
times the number of human cells. Yes, bacteria, such as those from the
genera Bifidobacterium and Lactobacillus, account for a large majority
of the 100 trillion creepy crawlies that call your body home.

*•*Aids our Digestive System: Bacteria offer multiple
benefits inside the human body. In the digestive system, they help
break down food like plant and fibres that we can’t digest on our own.
Lactobacillus helps break down the sugar.
*•
*•*Maximum Nutrition from food: According to Anne
Maczulak, bacteria in the digestive system supply us with the needed
vitamins like biotin and Vitamin K, and are our primary source for
some of these nutrients. In a nutshell, we get more nutrition from
food because of bacteria.
*•
*•*Keeps the harmful bacteria out: Many bacteria that
live inside the mouth, throat, nose and intestines do not let other
harmful microorganisms live inside or on the human body. The bacteria
in the intestines work with the immune system to protect the body
against various diseases. The bacteria residing inside the stomach
helps maintain the ph and acidity level in the stomach.
*•
*•*Safeguards our skin: The forest of bacteria on our
skin (almost 200 different species on a normal person) controls the
environment of the skin and its resources, keeping other harmful
bacteria from establishing a foothold.
*•
*•*Fortifies our Immune System: Exposure to bacteria
proved to be an important part of the development of our immune
system. Bacteria are known to prime the immune system to fight the
harmful viruses later in life. Children who are sheltered from
bacteria are prone to develop asthma and allergies.
https://www.toppr.com/bytes/humans-and-bacteria/

--------

{Nature_and_Environment.123.3}: Jay Hoffman {resist} Mon, 16 Dec 2019 21:13:17 CST (55 lines)

Bacteria eat iron from rocks for energy - and turn rocks into soil

"Bacteria have not only evolved a metabolism that opens niches to use
iron as an energy."

Some bacteria use iron that is deficient in electrons, reducing it to
a more electron-rich form of the element. Ironically, electron-rich
forms of iron can also supply electrons in the opposite "oxidation"
reaction, in which the bacteria literally "eat" the iron to get
energy.

Iron is the fourth-most abundant element on the planet, and because
free oxygen is scarce underwater and underground, bacteria have
"thought up," or evolved, a different solution: moving electrons to
iron while metabolizing organic matter.

These bacteria "eat organic matter like we do," says Roden. "We pass
electrons from organic matter to oxygen. Some of these bacteria use
iron oxide as their electron acceptor. On the flip side, some other
microbes receive electrons donated by other iron compounds. In both
cases, the electron transfer is essential to their energy cycles."
https://phys.org/news/2016-04-microbes-iron-oxygen.html


Ancient iron deposits shown to be formed by bacteria
The "bacteria evolved a metabolism that opens niches to use iron as an
energy".
https://phys.org/news/2015-06-iron-biological-element.html


Bacteria shown to eat solid rock and turn it in to soil

The iron-oxidizing bacteria revealed in the study occupy a range of
bacterial phyla, "meaning they are as different as zebras and frogs,"
Roden says.

Although the study focused on the dark, stable temperatures found at
the top of bedrock, iron-oxidizing bacteria may also play a role in
weathering higher up in the soil, Napieralski says. "External electron
transfer is a way to cope with the difficulty of eating iron. One big
thing in the paper is demonstrating that the organisms grew and
coupled the oxidation of iron to the generation of ATP, the 'energy
molecule' in all known types of life."

A full understanding of life requires an accounting of energy, Roden
says. "What we have found is that the (bacterial) cells make direct
contact with an otherwise insoluble mineral, and they pull electrons
from the mineral. They are getting energy from eating rock and along
the way supplying nutrients for plants—for life on Earth."

"In my opinion, this type of metabolism has been going on basically
forever, but unknown to us," says Roden. "This discovery opens up a
whole other way of thinking about the oxidative weathering of ferrous
silicate rock.
"https://phys.org/news/2019-12-hard-bacteria-soil.html"

--------

{Nature_and_Environment.123.4}: Jay Hoffman {resist} Tue, 17 Dec 2019 13:16:12 CST (49 lines)

The percentage of the human genome that arose at a series of stages in
evolution.

bacterial - 37%
eucaryotic  28%
animal ---- 16%
vertebrate  13%
primate ---  6%


Bacteria surround us

In many respects, it's easy to see the prominent role that bacteria
play in the world. Bacteria were one of the first life forms to appear
on Earth, about 3.8 billion years ago, and they will most likely
survive long after humans are gone. In the current tree of life, they
occupy one of the three main branches (the other two are Archaea and
Eucarya, with animals belonging to the latter). Although bacteria are
extremely diverse and live nearly everywhere on Earth, from the bottom
of the ocean to the inside of our intestines, they have a few things
in common. They are similar in size (a few micrometers), they are
usually made of either a single cell or a few cells, and their cells
don't have nuclei.

Although scientists have known for many years that animals serve as a
host for bacteria, which live especially in the gut/intestines, in the
mouth, and on the skin, recent research has uncovered just how
numerous these microbes are. Studies have shown that humans have about
10 times more bacterial cells in our bodies than we have human cells.
(However, the total bacteria weigh less than half a pound because
bacterial cells are much smaller than human cells.)

The true number of bacterial species in the world is staggeringly
huge, including bacteria now found circling the Earth in the most
upper layers of our atmosphere and in the rocks deep below the sea
floor.

Recent research has shown that animal development may be better
thought of as an orchestration among the animal, the environment, and
the coevolution of numerous microbial species. One example of this
coevolution may have occurred when mammals evolved endothermy, or the
ability to maintain a constant temperature of approximately 40 °C (100
°F) by metabolic means. This is also the temperature at which mammals'
bacterial partners work at optimum efficiency, providing energy for
the mammals and reducing their food requirement. This finding suggests
that bacteria's preferred temperature may have placed a selection
pressure on the evolution of genes associated with endothermy.
"https://phys.org/news/2013-02-bacterial-world-impacting-previously-
thought.html"

--------

{Nature_and_Environment.123.5}: Jay Hoffman {resist} Tue, 17 Dec 2019 13:19:57 CST (45 lines)

Bacterial signaling

Evidence for a deep-rooted alliance between animals and bacteria also
emerges in both groups' genomes. Researchers estimate that about 37%
of the 23,000 human genes have homologs with bacteria and Archaea,
i.e., they are related to genes found in bacteria and Archaea that
were derived from a common ancestor.

Many of these homologous genes enable signaling between animals and
bacteria, which suggests that they have been able to communicate and
influence each other's development. One example is Hadfield and his
group's discovery that bacterial signaling plays an essential role in
inducing metamorphosis in some marine invertebrate larvae, where the
bacteria produce cues associated with particular environmental
factors. Other studies have found that bacterial signaling influences
normal brain development in mammals, affects reproductive behavior in
both vertebrates and invertebrates, and activates the immune system in
tsetse flies. The olfactory chemicals that attract some animals
(including humans) to their prospective mates are also produced by the
animals' resident bacteria.

Bacterial signaling is not only essential for development, it also
helps animals maintain homeostasis, keeping us healthy and happy. As
research has shown, bacteria in the gut can communicate with the brain
through the central nervous system. Studies have found that mice
without certain bacteria have defects in brain regions that control
anxiety and depression-like behavior. Bacterial signaling also plays
an essential role in guarding an animal's immune system. Disturbing
these bacterial signaling pathways can lead to diseases such as
diabetes, inflammatory bowel disease, and infections. Studies also
suggest that many of the pathogens that cause disease in animals have
"hijacked" these bacterial communication channels that originally
evolved to maintain a balance between the animal and hundreds of
beneficial bacterial species.

Signaling also appears in the larger arena of ecosystems. For example,
bacteria in flower nectar can change the chemical properties of the
nectar, influencing the way pollinators interact with plants. Human
infants who are born vaginally have different gut bacteria than those
delivered by Caesarean section, which may have long-lasting effects.
And bacteria feeding on dead animals can repel animal scavengers—
organisms 10,000 times their size—by producing noxious odors that
signal the scavengers to stay away.
"https://phys.org/news/2013-02-bacterial-world-impacting-previously-
thought.html"

--------

{Nature_and_Environment.123.6}: Jay Hoffman {resist} Tue, 17 Dec 2019 13:24:57 CST (28 lines)

The big picture

Altogether, the recent studies have shown that animals and bacteria
have histories that are deeply intertwined, and depend on each other
for their own health and well-being as well as that of their
environments. Although the researchers focused exclusively on animal-
bacteria interactions, they expect that similar trends of codependency
and symbiosis are universal among and between other groups, such as
Archaea, fungi, plants, and animals. Once considered an exception,
such intermingling is now becoming recognized as the rule. Due to
these symbiotic relationships, the scientists here propose that the
very definitions of an organism, an environment, a population, and a
genome have become blurred and should be reviewed. It may be, for
instance, that animals are better viewed as host-microbe ecosystems
than as individuals.

In addition, the scientists predict that the recent findings on
animal-bacteria interactions will likely require biologists to
significantly alter their view of the fundamental nature of the entire
biosphere.

It is hard to summarize a single 'most important conclusion,' other
than the admonition to biologists studying animals, from behavior to
physiology and ecology to molecular biology, that no matter what
process you think you are studying, you must look for and consider a
major role for bacteria.
"https://phys.org/news/2013-02-bacterial-world-impacting-previously-
thought.html"

--------

{Nature_and_Environment.123.7}: Glen Marks {wotan} Tue, 17 Dec 2019 17:01:17 CST (8 lines)

According to this:

- Salmonella is a diverse group of bacterial pathogens that causes
foodborne infections. Infected patients often develop diarrhea,
nausea, vomiting and abdominal pain, though some infections are more
severe and can be life threatening.

"https://www.sciencedaily.com/releases/2019/11/191125103843.htm"

--------

{Nature_and_Environment.123.8}: Glen Marks {wotan} Tue, 17 Dec 2019 17:03:10 CST (4 lines)

Can salmonella bring down a civilization?:

"https://www.irishexaminer.com/breakingnews/world/the-aztec-
civilisation-was-probably-brought-down-by-salmonella-777593.html"

--------

{Nature_and_Environment.123.9}: Jay Hoffman {resist} Tue, 17 Dec 2019 17:23:15 CST (86 lines)

Good bacteria (essential to human life)- example one (gut bacteria)

About 100 trillion bacteria, both good and bad, live inside your
digestive system. Science has begun to look more closely at how this
enormous system of organisms influences—and even improves—health
conditions, from heart disease to arthritis to cancer.

This is a new frontier of medicine, and many are looking at the gut
microbiota as an additional organ system," says Dr. Elizabeth Hohmann
of the infectious diseases division at Harvard-affiliated
Massachusetts General Hospital. "It's most important to the health of
our gastrointestinal system, but may have even more far-reaching
effects on our well-being."

The gut microbiota in action

Within those trillions of gut bacteria are about 1,000 different
species, represented by some 5,000 distinct bacterial strains.
Everyone's gut microbiota is unique, but there are certain
combinations and collections of bacteria that are found in healthy
individuals.

Your gut microbiota plays many roles. It metabolizes nutrients from
food and certain medications, serves as a protective barrier against
intestinal infections, and produces vitamin K, which helps make blood-
clotting proteins.

But the gut microbiota may do much more. Most research has involved
only preliminary animal studies; however, initial findings suggest gut
bacteria may be the key to preventing or treating some diseases.

Here's a summary of the latest findings:

Cancer. A study published online April 13, 2016, by PLOS ONE offered
some evidence that a particular strain of the bacterium Lactobacillus
johnsonii may protect against some cancers. Scientists gave mice a
mutation that is associated with a high incidence of leukemia,
lymphomas, and other cancers. When treated with the bacterium, the
mice developed lymphoma only half as quickly compared with a control
group.

Heart disease. Research in the February 2016 Journal of Applied
Microbiology found the bacterial strain Akkermansia muciniphila could
prevent inflammation that contributes to fatty plaque buildup in
arteries. Scientists believe the effect was due to a protein that
blocks communication between cells in the inner lining of the gut. As
a result, fewer toxins from a poor diet could pass into the
bloodstream, which in turn reduced inflammation.

Immune system. In a study published online Nov. 5, 2015, by Science,
University of Chicago researchers found that introducing a particular
bacterial strain into the digestive tracts of mice with melanoma
prompted their immune systems to attack tumor cells. The gains were
comparable to treatment with anti-cancer drugs called checkpoint
inhibitors.

Says Dr. Hohmann. "Anything that can feed good bacteria and keep them
plentiful is good for overall health. When the gut is happy, you are
happy." Here are some suggestions on how to do that:

Do not overuse antibiotics. Again, overusing antibiotics can deplete
good gut bacteria. "In general, older people are more susceptible to
infections and have more medical problems, so they are more likely to
be prescribed antibiotics," says Dr. Hohmann. "These are important
lifesaving drugs, but they need to be used judiciously."

Don't be so quick to ask for antibiotics to fight viral ailments like
the common cold, she says. Also, if your doctor prescribes one, ask if
you really need it, what is the shortest treatment course, and whether
there are alternative methods.

Eat more fermented foods. Bacteria are living organisms that need to
eat. "A healthy, varied, balanced, high-fiber diet with complex
carbohydrates is good for the bacteria living in your gut and
encourages a diverse ecosystem," says Dr. Hohmann.

Other helpful dietary choices include naturally fermented foods
containing probiotics (live bacteria), such as sauerkraut, pickles,
miso, certain types of yogurt, and kefir (a yogurt-based drink).

People with depressed immune function from late-stage cancer or
chemotherapy should not take probiotics. Also, not all probiotic
preparations are the same, so discuss the options with your doctor
before you take one.
"https://www.health.harvard.edu/staying-healthy/can-gut-bacteria-
improve-your-health"

--------

{Nature_and_Environment.123.10}: Jay Hoffman {resist} Tue, 17 Dec 2019 17:44:40 CST (2 lines)

Organic Apples Have Way More Beneficial Bacteria Than Conventional Ones
https://www.livescience.com/66035-organic-apples-microbiome.html

--------

{Nature_and_Environment.123.11}: Jay Hoffman {resist} Tue, 17 Dec 2019 17:46:28 CST (65 lines)

New Weapons Against Cancer: Millions of Bacteria Programmed to Kill

Our immune cells can sometimes recognize and destroy cancer cells
without assistance. But tumors may hide from the immune system by
taking advantage of a gene called CD47.

Normally, the gene makes a protein that studs the surface of red blood
cells, a kind of sign that reads, “Don’t Eat Me.” Immune cells see it,
and pass by healthy red blood cells.

But as red blood cells age, they lose CD47 proteins. Eventually the
immune cells no longer give them a free pass, gobbling up old cells to
make way for new ones.

Mutations in cancer cells can cause them to switch on the CD47 gene.
The immune system sees these cells, too, as harmless, allowing them to
grow into dangerous tumors.

In recent years, scientists have been developing antibodies that can
attach to CD47 proteins on cancer cells, masking the “Don’t Eat Me”
sign. Then the body’s immune cells learn to recognize the cancer cells
as dangerous and attack.

But standard antibodies are big molecules that can’t burrow into a
large tumor. And since they have to be injected into the bloodstream,
these antibodies end up everywhere in the body, causing side effects.
Nicholas Arpaia, an immunologist at Columbia University in New York,
and Tal Danino, a synthetic biologist, wondered if they could use
bacteria to turn the immune system against cancer cells — but from
within tumors, rather than from outside.

Ordinary bacteria will colonize tumors in the body, using them as a
refuge from the immune system. In 2016, Dr. Danino helped construct
bacteria that can make drugs to fight tumors after entering them.

Bacteria cannot make normal antibodies for CD47. But recently, Dr.
Dougan and his colleagues developed a tiny version of the molecule
called a nanobody.

Not only are nanobodies small enough for bacteria to produce, they’re
also much more potent than conventional antibodies.

The researchers inserted the nanobody gene into the bacteria, turning
them into nanobody factories. Then the team injected five million of
the altered microbes into mouse tumors.

The bacteria were also programmed to commit mass suicide. After they
established themselves and multiplied, 90 percent of the bacteria
ripped themselves apart, spilling out nanobodies. The nanobodies
attached to CD47 proteins on the cancer cells, robbing them of their
camouflage.

In addition, fragments of the dead bacteria leaked out of the tumor.
These bits of debris drew the attention of immune cells, which
attacked the uncloaked cancer cells.

Inside the besieged tumor, the surviving bacteria started multiplying
again. When the population grew large enough, the majority committed
suicide once more — delivering another pulse of nanobodies and
fragments.

The double-whammy may eliminate the tumors into which the bacteria
were injected.
"https://www.nytimes.com/2019/07/03/science/cancer-bacteria-immune-
system.html"

--------

{Nature_and_Environment.123.12}: Jay Hoffman {resist} Tue, 17 Dec 2019 18:27:38 CST (20 lines)

How the nervous system doesn't merely detect presence of Salmonella,
it actively defends body against it by boosting the number of
protective gut bacteria (called SFB segmented filamentous bacteria)

Experiments showed that in the presence of Salmonella, gut neurons
fire back by releasing a neurochemical called CGRP, which slows down M
cell differentiation, thereby reducing the number of entry points that
Salmonella can use. Additionally, the experiments show, gut neurons
launch another form of defense. By releasing CGRP, they boost the
presence of SFB bacteria—microorganisms that, among performing other
beneficial functions, also guard against Salmonella invasion.

"Our findings illustrate an important cross talk between the nervous
system and the immune system," said study first author Nicole Lai,
research fellow in immunology in the Chiu lab. "It is clearly a
bidirectional highway with both systems sending messages and
influencing each other to regulate protective responses during
infection."
"https://medicalxpress.com/news/2019-12-nervous-doesnt-presence-
salmonella-defends.html"

--------

{Nature_and_Environment.123.13}: Jay Hoffman {resist} Tue, 17 Dec 2019 19:20:21 CST (76 lines)

The ratio of bacteria cells in humans is closer to 3 to 2 than 10 to 1

It's often said that the bacteria and other microbes in our body
outnumber our own cells by about ten to one. That's a myth that should
be forgotten, say researchers in Israel and Canada. The ratio between
resident microbes and human cells is more likely to be one-to-one,
they calculate.

A 'reference man' (one who is 70 kilograms, 20–30 years old and 1.7
metres tall) contains on average about 30 trillion human cells and 39
trillion bacteria, say Ron Milo and Ron Sender at the Weizmann
Institute of Science in Rehovot, Israel, and Shai Fuchs at the
Hospital for Sick Children in Toronto, Canada.

Those numbers are approximate — another person might have half as many
or twice as many bacteria, for example — but far from the 10:1 ratio
commonly assumed.

The 10:1 myth persisted from a 1972 estimate by microbiologist Thomas
Luckey, which was “elegantly performed, yet was probably never meant
to be widely quoted decades later”, say the paper’s authors. A
particular overestimate in Luckey’s work relates to the proportion of
bacteria in our guts, but most bacteria reside only in the colon
(which has a volume of 0.4 litres).

Putting together these kinds of calculations, the researchers produce
a ratio for microbial to human cells for the average man of 1.3:1,
with a wide uncertainty.

"https://www.nature.com/news/scientists-bust-myth-that-our-bodies-
have-more-bacteria-than-human-cells-1.19136"


More than half your body is not human

Human cells make up only 43% of the body's total cell count. The rest
are microscopic colonists.
Understanding this hidden half of ourselves - our microbiome - is
rapidly transforming understanding of diseases from allergy to
Parkinson's.

The field is even asking questions of what it means to be "human" and
is leading to new innovative treatments as a result.

"They are essential to your health," says Prof Ruth Ley, the director
of the department of microbiome science at the Max Planck Institute,
"your body isn't just you".

No matter how well you wash, nearly every nook and cranny of your body
is covered in microscopic creatures.

This includes bacteria, viruses, fungi and archaea (organisms
originally misclassified as bacteria). The greatest concentration of
this microscopic life is in the dark murky depths of our oxygen-
deprived bowels.

Originally it was thought our cells were outnumbered 10 to one.
"That's been refined much closer to one-to-one, so the current
estimate is you're about 43% human if you're counting up all the
cells," he says.

But genetically we're even more outgunned.

The human genome - the full set of genetic instructions for a human
being - is made up of 20,000 instructions called genes.

But add all the genes in our microbiome together and the figure comes
out between two and 20 million microbial genes.

Prof Sarkis Mazmanian, a microbiologist from Caltech, argues: "We
don't have just one genome, the genes of our microbiome present
essentially a second genome which augment the activity of our own.

"What makes us human is, in my opinion, the combination of our own
DNA, plus the DNA of our gut microbes."
"https://www.bbc.com/news/health-43674270"

--------

Forum
Topic HomeTopicsForum HomeForumsHomeSearchSettingsHelpExit
Guest-accessible forum This forum allows unregistered guests access to read. You must register to post in this forum.

You are in Guest mode. If you want to post, you'll need to register (we promise it's painless).
Registered users should log in now. (Forgot your password?)

The New Café  Home | Your Hotlist and Directory | Independent Partner Forums |
FAQ | User Guidelines | Privacy Policy