Bacteria and Viruses

Document Sample
Bacteria and Viruses Powered By Docstoc
					Feb 5th
   "What makes us all a little nervous is
    we are aware of the big outbreaks that
    occurred in Quebec," said John.
   A virulent strain of C. difficile is blamed
    for about 2,000 deaths between 2003
    and 2004 in Quebec hospitals.
   Patients with C. difficile at Victoria
    Hospital are treated with antibiotics and
    moved into private rooms. Families can
    still visit the patients, but are asked not
    to see any other patients at the
   Many hospitals are contaminated with
    C. difficile, a spore-forming bacteria
    that can survive for years, John said.
   C. difficile is the most common cause of
    infectious diarrhea in hospitals and long-
    term care homes. It usually occurs in
    patients receiving antibiotics. The
    antibiotics make patients more vulnerable
    by wiping out the normal bacteria in the
    bowel, providing a niche for C. difficile.
   "Most of us are protected if we have the
    normal bowel bacteria that prevent C.
    difficile from attaching to our gut," John
   C. difficile bacterium forming an
Fossils of Largest Snake
Give Hint of Hot Earth
   A batch of super-sized vertebrae were
    discovered in an open-pit coal mine in
    northeast Colombia
    Fossils of Largest Snake Give
    Hint of Hot Earth

   An artist’s rendering of the prehistoric snake
    Titanoboa cerrejonensis, which was 42 feet long and
    lived 60 million years ago.
Fossils of Largest Snake Give
Hint of Hot Earth
   Some 60 million years ago, well after the
    demise of the dinosaurs, a giant relative
    of today’s boa constrictors, weighing
    more than a ton and measuring 42 feet
    long, hunted crocodiles in rain-washed
    tropical forests in Columbia in northern
    South America, according to a new fossil
    Snakes are Ectotherms
   The team examined how warm it had to be
    for a snake species to be that large by
    considering conditions favoring the largest
    living similar tropical snake, the green
    anaconda, said the lead author of the paper
    and a paleontologist at the University of
    Toronto. They concluded that Titanoboa
    could have thrived only if temperatures
    ranged from 86 to 93 degrees.
   But the existence of such a large snake
    may also help clarify how hot the
    tropics became during an era when the
    planet, as a whole, was far warmer
    than it is now, and also how well moist
    tropical ecosystems can tolerate a much
    warmer global climate.
   That last question is important in
    assessments of how global warming
    might affect the tropics. Some scientists
    foresee the Amazon’s drying up, for
    instance, although other work cuts
    against that conclusion.
   tropical conditions today —an annual
    average temperature of 75 to 79
    degrees Fahrenheit.
    Arthur Caplan says
   ―There are two reasons to try to apply
    cloning to people. One is to create
    embryos so that stem cells can be taken
    from them and used to develop
    treatments against disease. The other is
    to make a clone of you or me.‖

   A team in the US created dozens of cloned
    embryos from a 10-year-old male macaque,
    the journal Nature reports
   The American group was able to extract stem
    cells from some of the cloned monkey
    embryos, persuading them to develop into
    mature heart and nerve cells in the
Therapeutic Cloning
   Stem cells from early embryos could
    potentially be used to provide new
    treatments for incurable diseases such
    as Alzheimer's, diabetes and
Who is the real Dolly?
   Dolly the world’s
    first cloned sheep at
    the Roslin Institute
   When?
       1997
   Where?
       Scotland
Nuclear Transfer
involved fusing a
donated cell with
an egg from
which the
nucleus had been
    Dolly the cloned sheep dies
    Last Updated Fri, 14 Feb 2003 22:11:27
    LONDON - Dolly, the world's first
    mammal cloned from an adult, has
    been euthanized, scientists said Friday.
   A veterinary exam confirmed the six-
    year-old sheep had a progressive lung
    disease. Her cells had started to show
    signs of aging faster than a typical
How can we tell if clones
age prematurely?
   Cell structures called
    telomeres gradually
    shorten as cells
    divide and age.
   This can lead to
    genetic errors that
    result in disease.
   In the case of Dolly, her telomeres were
    shorter than scientists would expect for a
    sheep of her birth age. This does not
    necessarily mean that she was ageing
    prematurely, as there is no proven link
    between shortened telomeres and premature
    ageing. And other clones don't show signs of
    telomere shortening.
   We need to study whether diseases that are
    common in old age, such as arthritis, occur in
    a normal way in cloned animals.
How old was Dolly?
   That depends on whether you mean her
    birth age - six years - or her genetic
    age - twelve years.
   Dolly was born in 1997, but all the cells
    in her body originate from genetic
    material extracted from the udder of a
    six-year old sheep.
One week earlier
   Australia's first cloned ewe
    dies mysteriously
    Last Updated Fri, 07 Feb 2003
    11:45:50 CANBERRA - Australia's
    first cloned sheep has died
    unexpectedly. Independent post-
    mortem tests failed to identify the
    cause of death, scientists said
        Can Clones Reproduce?
   The Australian ewe
    bore 3 lambs
   Dolly gave birth to 6
       Here she is with her
        first lamb, Bonnie
   How will these issues affect the
    prospects for cloned organ
    transplants, or the commercial
    farming of cloned animals?
   Cloning technology is being used to
    genetically modify pigs to make their organs
    more compatible with the human immune
    system. But these animals will be bred
    naturally to create many animals to use as
    organ donors.
   Since the health problems of clones don't
    seem to appear in their offspring, cloning
    defects may not be a problem for
   But if cloned animals do die early this may
    complicate plans to clone copies of desirable
    animals, such as "supercows" which produce
    unusually high amounts of milk.
   If the illnesses that clones develop are easily
    screened for and treated, or don't occur until
    after the animal is too old to be productive,
    cloned animals might still be useful.
           Raising the dead
   From New Scientist 04 May 2002.
   Calf cloned using cells from a side of
   A COW has been cloned using cells taken
    from a side of beef, 48 hours after slaughter.
    This might mean ranchers could select their
    breeding stock after they've seen the quality
    of meat it will produce -though the clones
    themselves would not be eaten.
Cloning Endangered Species
   On January 8, 2001,
    scientists at Advanced
    Cell Technology, Inc.,
    announced the birth of
    the first clone of an
    endangered animal, a
    baby bull gaur (a large
    wild ox from India and
    southeast Asia) named
   Noah died of an
    infection unrelated to
    the procedure.
Cloning Extinct Organisms
                August 21, 2002
              reports
                Japanese scientists are
                 planning to use tissue
                 from the legs and
                 testicles of a dead
                 mammoth to clone the
                 extinct creature and
                 display it at an Ice Age
                 wildlife park in Siberia.
Six years ago
   Sect claims to have cloned human
    Last Updated Sat, 28 Dec 2002
   HOLLYWOOD, FLA. - Many in the
    scientific community were left deeply
    skeptical after a Quebec-based religious
    sect, Clonaid, announced Friday it had
    created a human clone.
    TEX. - Scientists in
    Texas have cloned a
    female calico kitten,
    named "Cc:",
    believed to be the
    first pet successfully
   The kitten was born
    on Dec. 22, 2001
   The cat was cloned at Texas A&M
    University as part of the $3.7-million
    (US) "Missyplicity Project," which is
    attempting to clone Missy, a mixed-
    breed dog, for her wealthy owners.
   The researchers anticipate that the
    cloning of pets may be a popular
       The Missyplicity Project
   http://www.missypli
Who Are These Folks?
Korean scientist cloned a dog,
but the rest was fake, panel says
South Korean scientist Hwang Woo-suk

   Only last summer his government gave him the
    Orwellian title of "Supreme Scientist".
   They promised funding of up to $15m after he
    claimed to have extracted human stem cells from
    embryos he had cloned.
   But in the spring of 2006, Seoul National University
    confirmed what many of the world's stem cell
    scientists had feared - that Dr Hwang's human
    cloning claims were fake.
          Magic and Stem
          A South Korean firm RNL
           Bio said it had
           successfully cloned two
           puppies from a beagle
           using stem cells from the
           dog's fat tissue.
Should we clone humans?
Who would we clone?
Cloning Isn’t That Easy
               Dolly was only
                cloned after 276
First Cloned Horse Created in
Italy    Washington Post Staff Writer Thursday, August 7, 2003;

   The clone with her
    mother, whose skin
    cell was used to
    make the cloned
    embryo. The two
    are twin sisters.
   Scientists Could
    Copy Prizewinners
Cloning Yields Human-Rabbit
       Hybrid Embryo
   Washington Post Staff Writer
    Thursday, August 14, 2003; Page A04
   Scientists in China have, for the first
    time, used cloning techniques to create
    hybrid embryos that contain a mix of
    DNA from both humans and rabbits
Cloning Yields Human-Rabbit
       Hybrid Embryo
   More than 100 of the hybrids, made by
    fusing human skin cells with rabbit
    eggs, were allowed to develop in
    laboratory dishes for several days
    before the scientists destroyed them to
    retrieve so-called embryonic stem cells
    from their interiors
Cloning Yields Human-Rabbit
       Hybrid Embryo
   The vast majority of the DNA in the embryos
    is human, with a small percentage of genetic
    material -- called mitochondrial DNA --
    contributed by the rabbit egg.
   No one knows if such an embryo could
    develop into a viable fetus, though some
    experiments with other species suggest it
    would not.

   Wednesday, January 21, 2004
   BLACKSBURG, Va. (AP) - Scientists looking for a
    surefire way to stop mad cow disease are trying to
    clone cattle that are genetically engineered to resist
    the deadly brain-wasting illness.
   The Biotechnology Industry Organization, a
    Washington trade group, says at least three research
    teams are trying to produce clones. One of those, a
    team in Korea, announced last month the birth of
    four "mad-cow-proof" calves.
BBC - Sunday, 17 October, 2004
   The United Nations should ignore a call
    by George Bush to ban all forms of
    human cloning, say UK scientists.
   The US president told the UN last month
    member countries should support a Costa
    Rican proposal to ban both reproductive and
    therapeutic cloning.
    Is cloning "unnatural“?
   Not at all - some organisms in nature
    only reproduce using cloning - not only
    bacteria and yeasts, but also larger
    organisms like some snails and shrimp
   A shrimp called Artemia
    perthenogenetica - has survived for at
    least 30 million years.
    Is cloning "unnatural“?
   In nature sexual reproduction is the
    only way to improve the genetic stock
    of a species, most asexual species tend
    to die off
   Many more species, including the aphid,
    reproduce by cloning most of the time,
    only reproducing sexually every few
Sea cucumbers clone themselves:
biologists Last Updated Thu, 11 Sep 2003 10:36:22
   Now researchers
    have determined
    that three new
    groups of
    echinoderms – sea
    cucumbers, sand
    dollars and sea
    urchins – can
    spontaneously clone
Advantages of Cloning
   They suggest larval cloning may offer
    three potential ecological advantages:
       help increase fertility under ideal conditions
       Increase chances of settlement after the
        larval stage
       recycling of larval tissue

Fanshawe’s Own

Shared By: