Posts tagged developmental biology
Oh Yeah, Developmental Biology!
A transmission electron micrograph image of numerous HIV virions.
HIV is the virus that can lead to acquired immune deficiency syndrome, or AIDS. CDC estimates that about 56,000 people in the United States contracted HIV in 2006.
There are two types of HIV, HIV-1 and HIV-2. In the United States, unless otherwise noted, the term “HIV” primarily refers to HIV-1.
Both types of HIV damage a person’s body by destroying specific blood cells, called CD4+ T cells, which are crucial to helping the body fight diseases.
- CDC PHIL
Image provided by Maureen Metcalfe &Tom Hodge via the CDC PHIL
This whole blog is really good I suggest you all follow them
(Source: biologylair)
Skin cells turned into healthy heart muscle cells
Scientist say they have managed to turn patients’ own skin cells into healthy heart muscle in the lab.
Ultimately they hope this stem cell therapy could be used to treat heart failure patients.
As the transplanted cells are from the individual patient this could avoid the problem of tissue rejection, they told the European Heart Journal.
Saltwater Crocodile embryos. Image 1 15 days after fertilisation. Image 2 just prior to hatching.
The saltwater crocodile (Crocodylus porosus) is the largest of allcrocodilians, and the largest reptile in the world, with unconfirmed reports of individuals up to an impressive eight to ten metres in length, although a maximum of five to six metres is more usual(2) (3) (5). The species has a relatively large head, with a pair of ridges that run from the eye along the centre of the snout. Adults are generally dark in colour, with lighter tan or grey areas, and dark bands and stripes on the lower flanks. The underside is creamy yellow to white, becoming greyer along the tail. The juvenile is usually pale tan, with black stripes and spots on the body and tail, which gradually fade with age, although never disappear entirely. Female saltwater crocodiles grow to a smaller size than males, normally reaching a maximum length of 2.5 to 3 metres (3).
With its long, powerful tail, webbed hind feet, and long, powerful jaws, the saltwater crocodile is a superbly adapted aquatic predator. As in all crocodilians, the eyes, ears and nostrils are located on top of the head, allowing the crocodile to remain almost totally submerged when lying in water, helping to conceal it from potential prey, while a special valve at the back of the throat allows the mouth to be opened underwater without water entering the throat (2) (6). The saltwater crocodile is considered to be more aquatic than most crocodilians, and is less heavily armoured along the back and neck (3).
'Gay cure' psychiatrist apologises for flawed study
A leading psychiatrist whose controversial study backed therapies to make gay people straight has admitted it was flawed and apologised to homosexuals for implying that they could be “cured”.
In 2003, Robert Spitzer, while at the New York State Psychiatric Institute,published a paper in Archives of Sexual Behavior concluding that “reparative” therapy – which can include aversive conditioning and spiritual intervention – could change sexual orientation. He reached this conclusion after interviews with 200 self-selected individuals who claimed to have become heterosexual after the therapy.
In a letter published in the same journal this week, Spitzer speaks of the “fatal flaw” in his study: the impossibility of telling whether his interviewees had genuinely changed sexual orientation.
“I believe I owe the gay community an apology for my study making unproven claims of the efficacy of reparative therapy,” he writes.
Journal reference:Archives of Sexual Behavior, DOI: 10.1007/s10508-012-9966-y
Effect of apoptosis during paw development in the mouse.
In mice, humans, and other mammals, as well as in land birds, the embryonic region that develops into feet or hands initially has a solid, plate-like structure.
Apoptosis eliminates the cells in the interdigital regions, forming the digits. The cells undergoing apoptosis are stained to appear bright yellow.
Apoptosis of cells begins at the margin of each inter-digital region (left), & is no longer visible when the inter-digital tissue has been eliminated (right) (fluorescence LMs)
Abnormal apoptosis can lead to syndactyly.
Drug-smuggling nanoparticles target tumours
Drug-smuggling nanoparticles could be the latest recruits in the fight againstcancer. The first results from early-stage trials show that cancer drugs couriered by nanoparticles may reduce the size of tumours in humans.
Researchers from BIND Biosciences in Boston filled nanoparticles with the cancer drug docetaxel and injected them into the blood of 17 people who had cancers that are normally resistant to the drug. Forty-two days later, two of the volunteers’ tumours had shrunk in size significantly, and the rest of the volunteers’ tumours had not grown.
When injected into the body, docetaxel doesn’t discriminate between healthy and cancerous cells. However, the nanoparticles only released their payload when they reacted with molecules on the tumour’s surface, so up to 80 per cent less of the drug needed to be injected to get the same amount into the tumour.
As a result, physicians should be able to up the concentration of the drug without worrying about toxic side effects, says Jeffrey Hrkach, senior vice-president at BIND. He says larger clinical trials are in the pipeline.
Journal reference: Science Translational Medicine, DOI: 10.1126/scitranslmed.3003651
So at the California ScienCenter last week they had this.
Life-extending drug without the negative side effects
It was a bittersweet discovery: a drug that extends life but at the cost of causing diabetes. Now the drug’s dual nature has been teased apart, raising the prospect of a new life-prolonging drug without the harmful side effects.
Rapamycin is regularly given to prevent transplant rejection and treat cancer. Previous studies have also shown that it extends the life of animals, but simultaneously causes glucose intolerance – a side effect reported in humans, too.
David Sabatini of the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, and colleagues, gave the drug to strains of mice that had genes for certain proteins silenced. They found that rapamycin acts on two important nutrient-sensing proteins called MTORC1 and MTORC2. Its effect on the gene for MTORC1 prolongs life, while its action on MTORC2 causes diabetes.
Sabatini’s team is now developing variants of rapamycin that act only on the gene for MTORC1. “If we could just target MTORC1, we could preserve longevity effects and get rid of the unwanted side effects,” he says.
Human cerebral cortex development from pluripotent stem cells to functional excitatory synapses | Nature Neuroscience
Efforts to study the development and function of the human cerebral cortex in health and disease have been limited by the availability of model systems. Extrapolating from our understanding of rodent cortical development, we have developed a robust, multistep process for human cortical development from pluripotent stem cells: directed differentiation of human embryonic stem (ES) and induced pluripotent stem (iPS) cells to cortical stem and progenitor cells, followed by an extended period of cortical neurogenesis, neuronal terminal differentiation to acquire mature electrophysiological properties, and functional excitatory synaptic network formation. We found that induction of cortical neuroepithelial stem cells from human ES cells and human iPS cells was dependent on retinoid signaling. Furthermore, human ES cell and iPS cell differentiation to cerebral cortex recapitulated in vivo development to generate all classes of cortical projection neurons in a fixed temporal order. This system enables functional studies of human cerebral cortex development and the generation of individual-specific cortical networks ex vivo for disease modeling and therapeutic purposes.
(via fuckyeahneuroscience)
The Cell’s Muscles and Bones
Cell movement begins with lamellipodia. A thin sheet of actin filaments (light purple) that stretches out to the cell’s periphery, lamellipodia generate pushing forces that drive the cell forward. Microtubules (cyan) can barely penetrate this actin network, but they direct cell motility in other ways, such as controlling cell adhesion and acting as the cell’s internal compass.
Image: A human HaCat keratinocyte responds to epidermal growth factor by rapidly forming a lamellipod around most of its perimeter. The cell was fixed and processed within minutes after EGF addition. F-actin is stained with fluorescently labeled phalloidin (light purple), and microtubules are labeled with an antibody (cyan). DNA dye stains the nucleus dark purple.
