Biofluorescent Night Dive - Dahab/Red Sea (Egypt), Masbat Bay/Mashraba, "Roman Rock". You can see feather stars and hermit crab on fire coral, porcupine fish, pufferfish, scorpion fish, cuttlefish, anemones, among others.
The vasculature in a mouse retina. Two-photon confocal microscopy photo of the vasculature in the retina of an 8 day old baby mouse, visualized to distinguish vessels at different layers (red, top layer; blue, bottom layer). By F. Milde and M. L. Iruela-Arispe, (UCLA). After birth, the vascular bed expands rapidly and it shows all the sprouting, branching, fusion, remodeling, etc,. necessary to form new blood vessels. Go to the link for more great pictures of networks of tubes.
RANDOM INTERESTING LINK
And since it’s the end of the world, I thought I’d feature a few revolting or downright scary science news and facts, to match the mood of a zombie apocalypse.
How Maggots Heal Wounds. We associate maggots with death, putrefaction, and sliminess. They are perhaps the ultimate creepy crawlies. But for centuries they have been used to help heal and close wounds, because they can eat the dead tissue, and promote healing. They are still used nowadays in controlled medical facilities to help heal difficult to treat wounds: in 2004, the U.S. Food and Drug Administration approved maggot therapy as a prescription treatment, for cases that are antibiotic resistant. But how do maggots help wound healing? New research shows that the slime of fly larvae contribute to wound healing because it is an immune-suppressant, it suppresses the inflammatory response. A team of Dutch surgeons treated blood samples with maggot secretions and they measured complement proteins, which mediate our body's inflammatory response. They found that the treated normal blood samples reduced the levels of complement proteins by up to 99%. They found degraded complement proteins, indicating the maggot slime had broken down or digested the complement proteins. They also found that treating the blood of patients with severe wounds, who already had a full-blown inflammatory response, reduced in half complement protein levels. Interestingly, the secretions were effective even after boiling and after being stored for a month. Once the compounds responsible for inhibiting the complement proteins can be isolated to be used as drugs, there will be no need to subject patients to the presence of the maggots on their wounds.
Neurons out of urine. Have you ever considered the fact that everyday you are pissing out some potential neurons? Every time we urinate, we shed cells. Not neurons, to be sure, but ordinary epithelial cells. And team of stem cell biologists lead by Duanqing Pei from the Guangzhou Institutes of Biomedicine and Health, part of the Chinese Academy of Sciences has found a way to “transform” the shed cells into neural progenitor cells. Dr. Pei’s group had previously figured out how to reprogram kidney epithelial cells from urine into induced pluripotent stem cells (iPS), which can basically be transformed into any type of cell in the body. But their previous work utilized a retroviral vector to insert genes that induced pluripotency into the epithelial cells, and the problem with this technique is that genes introduced by retroviruses integrate into the genome of the cells and thus induce instability, which can lead to the formation of tumors. In this new study, they introduced the pluripotency genes into the cells by using a different vector that does not integrate into the genome. pluripotency genes into cells — a common technique in cell reprogramming. This alters the genetic make-up of cells and can make them less predictable, so in this study, Pei and his colleagues introduced the genes using vectors, which did not integrate in the cellular genome. When these cells are cultured in a growth medium used for neurons, they got reprogrammed into fully functional neurons. When these were implanted in the brains of baby rats, they did not form tumors and 4 weeks later, they were traced and identified as normal looking neurons. These neurons can be used to study disorders such as autism or other neurogenetic disorders. Many of these disorders manifest in childhood and collecting urine from children is a lot easier than drawing blood or obtaining samples through other more invasive means.
ENDLESS FORMS MORE SCARY
The spider that makes a spider sculpture. A spider from the Amazon forest in Peru makes spider decoys on its web. The sculptures are much larger than the actual spider, and are made out of insect parts and debris. It does look like a spider, and the scientists who discovered the spider presume it is a defense mechanism against predators. The spider could be a new species of the genus Cyclosa, but a final species determination has not been done yet because it will require collecting more specimens. Cyclosa spiders are known for making "sculptures" out of debris on their webs but never in the form of a spider. The tiny spider actually rushed in to shake the web when the scientist approached, and at first he thought the sculpture was actually a live spider, until he noticed the little puppet-master doing the shaking. After finding this spider, he went around looking for more and found 25 more spider-sculpting spiders in a 1 mile radius area. I think this is fantastic.
Megapiranha. Piranhas are fairly small fish, even though the black piranha (Serrasalmus rhombeus), the largest living species, can measure >30 cm in length and weigh around 1 kilogram. Scientists measured the bite force of the black piranha and the fish came on top of any other vertebrate ever tested. The fish can clamp down with a force ~30 times greater than its own weight. Enter the black piranha’s extinct relative, Megapiranha paranensis, which lived 10 million years ago and measured >1 meter in length and weighed ~70 kg, as much as a man. Believe it or not, scientists have fun calculating the bite force of extinct monsters, and although T. rex presumably had a bite force 3 times greater than Megapiranha. But since T. resx is 100 times heavier than the extinct monster fish, Megapiranha wins the competition on a kilogram-by-kilogram basis. The extrapolated bite force of Megapiranha is calculated at close to 500 Kg. In addition, the teeth of the extinct piranha are serrated and had robust circular roots, making them strong enough to slice through the carapace of the extinct turtles or armor-plated catfish that lived in the same ancient ecosystem.
BRAIN AND MIND
The psychology of believing in the apocalypse. Why are some people attracted to doomsday prophecies such as this latest misreading of the Mayan calendar? And why are some people so willing to believe such end of the world scenarios? Psychologists and neuroscientists weigh in. We were primed by evolution to respond to any hint of alarm with fear, because of our fast-acting amygdala, says neuroscientist Shmuel Lissek (University of Minnesota). In addition, experiments show that when we can predict an unpleasant experience, such as an electric shock, we relax. Uncertainty is more stressful. From a psychological point of view, it is well known that people whose beliefs are strongest are also most motivated to spread their beliefs (that’s how religious beliefs spread, in my opinion). Steven Schlozman, a Harvard child psychiatrist who also wrote zombie apocalypse novels (interesting combination!) says in his clinical experience people romanticize end-of-time scenarios in which a few survive and go back to living more “naturally” because it sounds simpler than today’s world in which people are primed to panic because of terrorism, war and other conflicts, and climate change. I have actually never met anyone personally who believes in any conspiracy theory or end of the world scenario, have you?
Stress, depression and dopamine neurons. Two recent Nature articles show that dopamine neurons in a small area of the midbrain, called the ventral tegmental area (VTA), are responsible for the symptoms of stress, at least in mice. The fascinating aspect is that depending on the type of stress that was used to induce depression in mice, activating or silencing the dopamine neurons had opposite effects on depression. First, some interesting asides. Yes, mice do get depressed. The animals are less motivated to fight or escape if picked up by the tail, and they no longer bother to sip their favorite sugary beverage: they seem to no longer be able to experience pleasure. They also are not interested in exploring new spaces, which all normal mice do. Second, the neuroscientists used optogenetics to silence or activate specific neurons with bursts of light, which is a fantastic new technology that allows the precise manipulation of certain neurons. One team of scientists showed that silencing the VTA dopamine neurons made normal mice act depressed instantly, and making these neurons fire in short bursts after the mice had been depressed for weeks, following conditions of extended, mild stress, immediately reverse the symptoms and the mice stared acting normal. Another team o scientists showed the opposite effect: when they made the VTA neurons fire in phase, resilient animals showed depression-like symptoms and when they silence those same neurons, the susceptible animals became resilient. The difference is in this case, the susceptible mice had been made depressed by “social defeat”, constantly exposing them to dominant, aggressive animals. Thus, depression that was caused by different types of stress may have completely opposite neurological parameters. On one hand, the experiments reinforce the role of the dopamine system in depression, but on the other hand, they suggest the reason why it is so difficult to treat depression, and why some drugs work for some patients and not others, and in some even worsen the symptoms.
NASA posts video debunking the Mayan calendar “end of the world” nonsense, a day ahead of December 22, 2012. The Mayan calendar is actually fascinating stuff!