sugaratoms:

image credit 

This baby, pictured in yellow, is a nucleus. They contain genetic information for every single eukaryotic cell (apart from mitochondrial DNA, and the DNA of chloroplasts).  They are the most conspicuous organelle under the microscope, appearing as a darker, denser area. The nuclear envelope separates the nuclear contents from the cytoplasm. The double membrane (nuclear envelope) is periforated by pores 100nm in diameter. At the lip of each pore, the inner and outer membranes are continous, leaving a space between them of 20-40nm. The inside of the envelope is lined with the nuclear lamina, a netlike array of protein filaments which serve to maintain shape. There is also much evidence for a nuclear matrix within. DNA is present as chromatin or chromosomes in the nucleus, with each species having a characteristic number of chromosomes and genes. A nucleolus is present within the nucleus and is identified as densely stained granules and fibres. The nucleolus synthesises rRBA and studies suggest it also plays a part in is regulation of cellular processes (such as division).

biologylair:

The above images are photomicrographs using fluorescent microscopy from the Nikon Small World Competition Galleries.

decaturjim:

Three dimensional structure of the Ebola virus

The causative agent of viral hemorrhagic fever in humans and a potential biological weapon, Ebola virus is presented here in beautiful, three dimensional form.

The Ebola-encoded structures are shown in maroon, while human cells are shown in grey. This model was based on 20 years of virology data, X-ray analysis, and computation biology techniques.

biologylair:

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

jewbones:

A tooth in the late bell stage of development

defbyte:

This is amazing!

A scanning electron microscope image of spider silk glands making a thread originally from Dennis Kunkel Microscopy.

ucsdhealthsciences:

Staphylococcus aureus, magnified 50 thousand times.

Hormone Plays Surprise Role in Fighting Skin Infections
Boosts immune response when vitamin D levels are low

Antimicrobial peptides (AMPs) are molecules produced in the skin to fend off infection-causing microbes. Vitamin D has been credited with a role in their production and in the body’s overall immune response, but scientists at the University of California, San Diego School of Medicine say a hormone previously associated only with maintaining calcium homeostasis and bone health is also critical, boosting AMP expression when dietary vitamin D levels are inadequate.

The finding, published in the May 23, 2012 online issue of Science Translational Medicine, more fully explains how the immune system functions in different situations and presents a new avenue for treating infections, perhaps as an alternative to current antibiotic therapies.

The immunological benefits of vitamin D are controversial. In cultured cell studies, the fat-soluble vitamin provides strong immunological benefits, but in repeated studies with humans and animal models, results have been inconsistent: People with low levels of dietary vitamin D do not suffer more infections. For reasons unknown, their immune response generally remains strong, undermining the touted immunological strength of vitamin D.

Working with a mouse model and cultured human cells, Gallo and colleagues discovered why: When levels of dietary vitamin D are low (it’s naturally present in very few foods), production of parathyroid hormone (PTH), which normally helps modulate calcium levels in blood, is ramped up. More PTH or a related peptide called PHTrP spurs increased expression of AMPs, such as  cathelicidin, which kill a broad spectrum of harmful bacteria, fungi and viruses.

“No one suspected a role for PTH or the PTH-related peptide in immunity,” said Richard L. Gallo, MD, PhD, professor of medicine and chief of UCSD’s Division of Dermatology and the Dermatology section of the Veterans Affairs San Diego Healthcare System. “This may help resolve some of the controversy surrounding vitamin D. It fills in the blanks.”

More here

iamcontessa:

Microscopic morphology of the saprophytic or mycelial form of Sporothrix schenckii when grown on Sabouraud’s dextrose agar at 25°C. Note clusters of ovoid conidia produced sympodially on short conidiophores arising at right angles from the thin septate hyphae.

bioguru:

Lovely SEM image of pseudostratified ciliated columnar epithelium. This tissue lines the trachea and upper respiratory tract, and is responsible for sweeping debris out of your lungs, up your wind pipe, and into the back of your throat where you’ll either a) cough it out or b) swallow it. People who are smokers are constantly killing off these cells, which is why smokers are so prone to lung infections; they lack the ciliated cells to keep crap out of their lungs.

indiangeek:

Thrombus. Coloured Scanning Electron Micrograph (SEM) of a thrombus (blood clot) inside a coronary artery of the human heart. The artery has been cross-sectioned, showing its wall (brown) and inner lumen (blue). A blood clot (red) is seen, blocking about 30% of the width of the artery. Two coronary arteries supply blood to the heart muscle. A clot in one of these arteries (called coronary thrombosis) is most commonly caused by the build-up of atheroma (fatty deposits) on the artery walls. Impeded blood flow from a clot starves the heart of oxygen and may lead to heart attack.