THE ECOLOGY OF BACTERIOPHAGES
Studies have shown that bacteriophages (viruses that attack bacteria) are numerically the most abundant biological entities on the planet. [Bacteria themselves are the most abundant life form.]
In shotgun sequencing of marine samples, the majority of phage gene sequences are invariably found to be novel (that is, they don’t correspond to any already known gene sequences).
Hence, the bulk of genetic diversity on the planet may well be tied up in viral/phage “dark matter.” (source)
HOW PHAGES WORK
Phages are quite specific. They attack only the strain of bacteria they evolved to inhabit and kill. And they only attack bacteria: other types of organisms lack the receptors required for phage infection.
No currently known bacteria are unaffected by phages. (This isn’t saying a lot, since we now know that most bacteria aren’t able to be studied in lab conditions.)
- [Image 1] Phages first attach to and puncture the bacterial membrane. Phage DNA is injected into the host cell. © Medi-Mation Ltd/Science Source
- [Image 2] The host cell’s DNA transcription is suppressed, and phage-specific proteins are synthesized instead. © Medi-Mation Ltd/Science Source
- [Image 3] New phages are assembled, the host cell membrane is disrupted, and large numbers of new phages are released from the host bacterium, which dies. © Medi-Mation Ltd/Science Source
There are somewhere between 1030 and 1032 phages in the biosphere.
It’s estimated that there are 1023 phage infections of bacteria every second.
In the course of any given 48 hour period, about half the total number of bacteria then living are destroyed by phages. This dynamic occurs in all ecosystems.
Phages have infected bacteria for billions of years, and just as bacteria mutate to resist drugs, they also mutate to render phages ineffective. However, new phages continually evolve against the mutated bacteria.
Maskull Lasserre: Skull Carved from Outdated Computer Books, ‘incarnate’
Maskull Lasserre was born in Alberta, Canada in 1978. He spent much of his childhood in South Africa before returning to Canada. He now works out of studios in both Montreal and Ottawa.human anatomy. twigs into spines.
Lasserre’s drawings and sculptures explore the unexpected potential of the everyday through allegories of value, expectation, and utility. Elements of nostalgia, accident, humor, and the macabre are incorporated into works that induce strangeness in the familiar, and provoke uncertainty in the expected.
Lasserre has exhibited across Canada and in the United States.
Engineered vaginas grown in women for the first time by Catherine de Lange | Image Credit: Cliparea/Shutterstock via Science Alert.
Vaginas grown in a lab from the recipients’ own cells have been successfully transferred to the body for the first time.
The surgery was carried out on four women who were born without vaginal canals because of a rare condition. The women, who were teenagers at the time of the operation, now have fully functioning sexual organs.
"After the operation they were able to function normally. They had normal levels of desire, arousal, satisfaction and orgasm," says Anthony Atala at Wake Forest School of Medicine in North Carolina, who led the research. He published the results only after four to eight years had elapsed following surgery, enough time for him to be sure there were no long-term complications.
The four women had undeveloped vaginas because they all have a severe form of a condition called Mayer-Rokitansky-Küster-Hauser Syndrome (MKRH), which affects about 1 in 5000 women. They also had some abnormal development of the uterus, although they did have a vulva – the external part of the sex organ which includes the labia and the clitoris. They were not able to have penetrative sex or menstruate. One of the women was diagnosed after her menstrual blood had collected in her abdomen.
As well as having physical implications, a diagnosis of MKRH is also a huge psychological burden for women.
Building on techniques the group developed in the 1990s and perfected on rabbits, Atala and his colleagues removed a small part of the vulva from each woman and grew the cells in the lab. After about four weeks they had enough cells to begin to lay them on to a degradable scaffold one layer at a time “like the layers of a cake”, he says.
The challenge was how to get the cells to grow to the right level of maturity in the lab, says Atala. You need to make sure that the cells are mature enough so that when you implant them into the body, they can recruit other cells in the body to form tissue that includes nerves and blood vessels.
Working with surgeons at the Federico Gomez Children’s Hospital of Mexico in Mexico City, Atala’s team used MRI scans to calculate the appropriate shape and size of the scaffolds for each patient. After cells had established themselves on these scaffolds, surgeons created a cavity in the abdomen and inserted the engineered vagina. It was then stitched in place, connected at the top to the uterus.
The women used a stent for six weeks to make sure the structure maintained the right shape.
The scaffold was made of a collagen matrix and degraded spontaneously over the months following surgery. In that time, the implanted cells matured into the normal tissue of the vaginal wall, including the right layers of muscle and epithelial cells (see video). The vagina was fully developed after six months, and the women were able to menstruate and have sex.
Better than a skin graft
Atala hopes that in the future, the technique could be used to treat not only women who have congenital vaginal defects but also those who have suffered damage through trauma – for instance, because of a car accident or cancer.
Currently it is possible to surgically create vaginas using grafts from either intestinal or skin tissue, but these can lead to severe complications. Skin cell grafts do not provide lubrication which causes pain during sex, and can thicken to the point where the vagina closes. Intestinal cells secrete mucus constantly, which is unhygienic and causes an unpleasant odour. Using the women’s own cells from the vulva gets around these issues.
Knowing that the engineered tissue originates from the recipient’s own body can be reassuring for them, says Sylvie Miot at the University of Basel, Switzerland, whose team has also successfully engineered new nostrils for patients who had to have skin cancers removed from their nose. Their findings are being published in the same issue of the Lancet.
Both studies involved small numbers of patients, but they provide the first strong evidence that nerve and blood vessels can reconnect to large patches of bioengineered tissues directly inside the body.
The findings also show that lab-engineered organs can grow to maturity healthily inside the body, says Martin Birchall at University College London. The women were aged between 13 and 18 years old when the surgery took place so their bodies were still developing. Birchall, who pioneered the first transplant of a human windpipe using the recipient’s stem cells, calls the results “very meaningful”.
One of the recipients, who wished to remain anonymous, said the treatment opened up new possibilities. “I truly feel fortunate, because I’ll have a normal life – completely normal,” she says. “It’s important to let other girls that have the same problem know that it does not end knowing that you have the disease, because there is a treatment.”
Two of the four women have a functional uterus, so the big question is whether they will be able to have children. “They haven’t tried,” says Atala, “but they can ovulate, so there is no reason to suspect that they cannot.”
Journal references: The Lancet, DOI: 10.1016/S0140-6736(14)60542-0 and 10.1016/S01460544-4
deep venous thrombosis (DVT) is the formation of a blood clot (thrombus) in a deep vein, predominantly in the legs. Non-specific signs may include pain, swelling, redness, warmness, and engorged superficial veins.
Images: Venograms of DVT
Here are some scientific facts about blood loss for all you
psychopathswriters out there.
yeah, for writting..
I need this guide for patient’s who think the little bit of blood they wiped means an emergency and I should immediately call for a rapid response right away!
Hmm I thought at 40%, blood volume is too low and any replacement of volume thereafter will not reverse the effects and organ failure is occurring. Did I learn wrong?
New Tool Pinpoints Genetic Sources Of Disease
Scientists have shown a connection between the “map” of genes in the genome and the “map” of reversible chemical changes to DNA, the epigenome. Their finding could help disease trackers find patterns in those overlays that could offer clues to the causes of and possible treatments for complex genetic conditions.
Robotic recreation of the Kangaroo form put together by Festo to demonstrate energy-efficient movement (this was initially announced on April the 1st, but turns out to be real) - video embedded below:
With the BionicKangaroo, Festo has technologically reproduced the unique way a kangaroo moves. Like its natural model, it can recover the energy when jumping, store it and efficiently use it for the next jump.
On the artificial kangaroo, Festo intelligently combines pneumatic and electrical drive technology to produce a highly dynamic system. The stable jump kinematics plus the precise control technology ensure stability when jumping and landing. The consistent lightweight construction facilitates the unique jumping behaviour. The system is controlled by gestures.
Taxidermy sheep cabinet for Salvador Dalí furniture collectionA stuffed lamb with a table on its back and a drawer in its side is the latest addition to a collection of furniture based on the paintings of Surrealist artist Salvador Dalí. The Xai side tables have been created from taxidermy lambs by attaching a circular wooden surface onto their backs and inserting a drawer that opens from one side of their abdomens. Hooves have been replaced with decorative rococo bronze feet. Their designer Oscar Tusquets Blanca referenced an image of a lamb with a telephone balanced on its spine and sliding storage in its stomach from Dalí’s 1942 painting Interpretation Project for a Stable-Library. Twenty-one lambs were chosen from a Parisian slaughterhouse and sent to taxidermist Maison Deyrolle, where Dalí was a frequent customer during his lifetime. The limited-edition set includes 20 white lambs priced at €36,500 (£30,350) each and a unique black piece costs €72,000 (£59,900).