Science is the poetry of Nature.







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Posts tagged "biology"

brains-and-bodies:

From Natural Selection

"While these organised structures might look like the work of an artist, they’re actually just the remnants left behind where a sand bubbler crab’s been snacking. 

During low tide they exit their burrows (as seen in the top pic) to scour the sand for tiny bits of organic debris in a radial motion. While eating, the crabs ball the excess sand on their heads, then discard it when it gets too big for them to see over, leaving behind a remarkable-looking reminder which helps them keep from searching for food in the same sand twice.

Each time High Tide returns, the small structures crumble and are washed away, all while leaving behind more food particles to fuel the tiny crab’s next accidentally artistic pursuits.”

Source: http://tinyurl.com/7vpzwj8
Video of the Sand bubbler crab in action:http://vimeo.com/6449515

(via azureamaryllis)

sciencenote:

By Dr. Sonja Pyott
Department of Biology and Marine Biology
University of North Carolina, Wilmington
Wilmington, NC, USA
Specimen: Cochlea and Hair Cells
Technique: Confocal

This confocal microscopy image of the organ of Corti is just stunning. Judges at the Olympus Bioscapes Digital Imaging Competition thought so too, and awarded Dr. Sonja Pyott 4th prize in the contest. For an even larger, more hi-res version, go here. Winners receive Olympus microscopes and other prizes! Guess who the 1st place winner is? Yeah, its the Brainbow mouse, which I discussed in a previous post.

The image above is of the normal mammalian organ of Corti, which is the epithelium which contains the sensory cells of the ear. Those cells are hair cells, which are stained green here with (I’m guessing) fluorescent phalloidin, which tags actin in the hair cells. The inner hair cells are in the lower left, and the three rows of outer hair cells are to the upper right. Nuclei of the inner hair cells are blue, which I’m guessing is DAPI. The spindly red things are the neurons, which are synapsing on the inner hair cells’ surface. The spiky things shooting out of the top of the inner hair cells are the stereocilia (which are made of actin, so green) which project into the fluid filled space above the organ of Corti. When sound waves are picked up by the ear canal and focused into the cochlea, the basilar membrane vibrates, causing the stereocilia to bend, which depolarizes the hair cells.

sciencenote:

Dr. David Maitland

Feltwell, Norfolk, United Kingdom
Specimen: Cocoa nut palm (Cocos comosa) stem with xylem vessel “eyes” in vascular bundle “faces.”
Technique: Differential interference contrast

wildcat2030:

Evolution’s Random Paths Lead to One Place
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A massive statistical study suggests that the final evolutionary outcome — fitness — is predictable.
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In his fourth-floor lab at Harvard University, Michael Desai has created hundreds of identical worlds in order to watch evolution at work. Each of his meticulously controlled environments is home to a separate strain of baker’s yeast. Every 12 hours, Desai’s robot assistants pluck out the fastest-growing yeast in each world — selecting the fittest to live on — and discard the rest. Desai then monitors the strains as they evolve over the course of 500 generations. His experiment, which other scientists say is unprecedented in scale, seeks to gain insight into a question that has long bedeviled biologists: If we could start the world over again, would life evolve the same way? Many biologists argue that it would not, that chance mutations early in the evolutionary journey of a species will profoundly influence its fate. “If you replay the tape of life, you might have one initial mutation that takes you in a totally different direction,” Desai said, paraphrasing an idea first put forth by the biologist Stephen Jay Gould in the 1980s. Desai’s yeast cells call this belief into question. According to results published in Science in June, all of Desai’s yeast varieties arrived at roughly the same evolutionary endpoint (as measured by their ability to grow under specific lab conditions) regardless of which precise genetic path each strain took. It’s as if 100 New York City taxis agreed to take separate highways in a race to the Pacific Ocean, and 50 hours later they all converged at the Santa Monica pier. The findings also suggest a disconnect between evolution at the genetic level and at the level of the whole organism. Genetic mutations occur mostly at random, yet the sum of these aimless changes somehow creates a predictable pattern. The distinction could prove valuable, as much genetics research has focused on the impact of mutations in individual genes. For example, researchers often ask how a single mutation might affect a microbe’s tolerance for toxins, or a human’s risk for a disease. But if Desai’s findings hold true in other organisms, they could suggest that it’s equally important to examine how large numbers of individual genetic changes work in concert over time. “There’s a kind of tension in evolutionary biology between thinking about individual genes and the potential for evolution to change the whole organism,” said Michael Travisano, a biologist at the University of Minnesota. “All of biology has been focused on the importance of individual genes for the last 30 years, but the big take-home message of this study is that’s not necessarily important.” (via Yeast Study Suggests Genetics Are Random but Evolution Is Not | Simons Foundation)

corporisfabrica:

Coronal and ventral x-rays of the hammerhead shark, Sphyrna mokarran.

The distinguishing feature of this animal is, of course, the highly unusual skull shape. You may once have wondered what exactly this seemingly clumsy structure contributes to this fearsome predator, and biologists still do. However, a number of theories exist to explain this unique adaptation; here are some of the best:

  1. All the better to see you with: mounting the eyes at either end of the broad skull allows excellent vision in all areas of the vertical plane. Hammerhead sharks, as hunters of bottom-dwelling animals, can use this superior angle of vision to better locate prey. 
  2. Another pair of fins. The head has evolved into the shape of an effective hydrofoil. It is thought that this may provide greater stability to the shark when making sharp turns and hunting.
  3. Heartbeat sensor. Like many sharks, the hammerhead possesses specialised electrosensory organs called the ampullae of Lorenzini. With these, it can detect the magnetic activity of the Earth and find its heading by means of biological compass. Much more impressively, the hammerhead can detect the minuscule electrical activity emitted by the muscle contractions of its prey, allowing location even when hidden from sight. Almost like a skull-mounted metal detector, the shark may sweep the seabed. All it takes is a heartbeat to give the game away. 

Photo credit to Dan Anderson.

(via afro-dominicano)

currentsinbiology:

Vaginal microbe yields novel antibiotic (Nature News)

Bacteria living on human bodies contain genes that are likely to code for a vast number of drug-like molecules — including a new antibiotic made by bacteria that live in the vagina, researchers report in this week’s issue of Cell1.

The drug, lactocillin, hints at the untapped medical potential of this microbial landscape.

“They have shown that there is a huge diverse potential of the microbiome for producing antimicrobial molecules,” says Marc Ouellette, a microbiologist at the University of Laval’s Hospital Centre (CHUL) in Quebec, Canada, who was not involved in the research.

Donia, M. S. et al. Cell 158, 14021414 (2014)

The antibiotic lactocillin was isolated from a Lactobacillus bacterium (shown here). BSIP SA / Alamy

(via afro-dominicano)

compoundchem:

With autumn on the horizon, this graphic looks at the chemicals behind the myriad colours of autumn leaves; bigger version & download here: http://wp.me/p4aPLT-sn

brains-and-bodies:

From Daily Anatomy

"This is where the sperms get produced: Cross section of a human testis tubule filled with sperm." (assuming they mean the seminiferous tubules?

Scanning electron micrograph, magnification x363.
By Richard Kessel

(via afro-dominicano)

In his 2014 book, Life at the Speed of Light: From the Double Helix to the Dawn of Digital Life, top synthetic biologist J. Craig Venter offers powerful words supporting a future shaped by ubiquitous synthetic biology in our lives:
“I can imagine designing simple animal forms that provide novel sources of nutrients and pharmaceuticals, customizing human stem cells to regenerate a damaged, old, or sick body. There will also be new ways to enhance the human body as well, such as boosting intelligence, adapting it to new environments such as radiation levels encountered in space, rejuvenating worn-out muscles, and so on”

fuckyeahfluiddynamics:

Sneezing can be a major factor in the spread of some illnesses. Not only does sneezing spew out a cloud of tiny pathogen-bearing droplets, but it also releases a warm, moist jet of air. Flows like this that combine both liquid and gas phases are called multiphase flows, and they can be a challenge to study because of the interactions between the phases. For example, the buoyancy of the air jet helps keep smaller droplets aloft, allowing them to travel further or even get picked up and spread by environmental systems. Researchers hope that studying the fluid dynamics and mathematics of these turbulent multiphase clouds will help predict and control the spread of pathogens. (Video credit: Science Friday)

medicalschool:

Early Heart Tube (Dorsal View)

Angiogenesis throughout the embryo allows for the development of angioblastic cords in the cardiogenic mesoderm of the embryo.

rhamphotheca:

Elephants Have 2000 Genes for Smell - Most Ever Found

We’ve long known that African elephants have a great sense of smell—but a new study shows that the large mammals have truly superior schnozzes.

by Christine Dell’Amore

Compared with 13 other mammal species studied, African elephants have the most genes related to smell: 2,000.

That’s the most ever discovered in an animal—more than twice the number of olfactory genes in domestic dogs and five times more than in humans, who have about 400, according to research published July 22 in the journal Genome ResearchThe previous record-holder was rats, which have about 1,200 genes dedicated to smell.

Why so many? “We don’t know the real reason,” study leader Yoshihito Niimura, a molecular evolutionist at the University of Tokyo, said by email. But it’s likely related to the importance of smell to the poorly sighted African elephant in interpreting and navigating its environment…

(read more: National Geographic)

photograph by João Nuno Gonçalves

(via simhasanam-deactivated20140822)

I meet many people offended by evolution, who passionately prefer to be the personal handicraft of God than to arise by blind physical and chemical forces over aeons from slime…What they wish to be true, they believe is true.

Only 9 percent of Americans accept the central finding of modern biology that human beings (and all other species) have slowly evolved by natural processes from a succession of more ancient beings with no divine intervention needed along the way.

Carl Sagan (via whats-out-there)

(via afro-dominicano)

Colonies of Growing Bacteria Make Psychedelic Art

Images: 1) P. vortex exposed to a chemotherapy substance 2) P. vortex 3) Vortex Blue (P. vortex) 4) A close look at P. dendritiformis 5) Bacterial Dragon (Paenibacillus dendritiformis)

Israeli physicist Eshel Ben-Jacob uses bacteria as an art medium, shaping colonies in petri dishes into bold patterns

(via afro-dominicano)

skeptv:

The Million Women Study: Understanding Women’s Health

The most comprehensive study of women’s health in modern history has yielded some surprising results. Professor Dame Beral presents these findings and advises on healthcare and lifestyle.

The Million Women Study, a national study of women’s health in collaboration with Cancer Research UK and the National Health Service, aims to answer many outstanding questions about the factors affecting women’s health.

The transcript and downloadable versions of the lecture are available from the Gresham College Website: http://www.gresham.ac.uk/lectures-and-events/the-million-women-study

Duration: 56:50

via Gresham College.