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When the scientists analyzed the water under a microscope, they quickly deduced what was causing the red liquid. In a newly-published study in Spanish Royal Society of Natural History Journal, they reveal that the culprit is Haematococcus pluvialis, a freshwater green microalgae that's capable of synthesizing a red carotene pigment called astaxanthin.

5 minute video: The evolution of whales has been a mystery. How did a large, big-brained mammal -- air-breathing, warm-blooded, giving birth to live young -- come to live entirely in water, when mammals evolved on land?

Researchers from the World Health Organization's International Agency for Research on Cancer (IARC) looked at more than 1,000 epidemiological studies and found that "excess body fatness" is also linked to the risk of developing gastric, liver, gallbladder, pancreatic, ovarian, thyroid, blood (multiple myeloma) and brain (meningioma) cancers.

In this interrupted case study, students shadow an endocrinologist as she tries to determine what is wrong with Angela Barber. Angela is a middle-aged woman presenting with symptoms suggestive of a thyroid issue. Students are given background information, patient history, and results from thyroid-specific blood tests. The exercise emphasizes the hypothalamic-pituitary-thyroid axis and particularly highlights the role of negative feedback. Students will use results from serum thyrotropin and thyroid hormone level tests, as well as patient symptoms, to come up with a diagnosis. In preparation for the diagnosis, students are asked to compare the endocrine profiles of patients with Graves' disease, Hashimoto's disease, iodine deficiency (primary hypothyroidism), and various tumors. The case was developed for college-level biology majors in a physiology course, but also has been used successfully for pre-nursing students in a non-majors anatomy and physiology course. Thus, this activity would be suitable for majors in physiology or pre-medical students, as well as allied health majors.

This interrupted case study tells the story of Michael, a Harvard law graduate with a stressful job and a seemingly heavy drinking problem. Students are provided with background information, medical history, and lab results in order to guide them towards determining what is wrong with Michael. This study highlights cirrhosis and the effects of alcohol abuse on the liver. Before beginning the case study, students should have a background in the physiological role of the liver and the breakdown of hemoglobin. Students are asked to use the information provided for them in the case study to gather more information about liver cells and their functions, alcohol, and alcoholic liver damage. Ultimately, using multiple blood tests, the Maddrey's discriminant function (DF) score, and results from a magnetic resonance elastography (MRE), they will diagnose Michael with alcoholic cirrhosis. This case was developed for use in a non-majors physiology course, but could easily be used for a majors class.

For Collinge, this led to a worrying conclusion: that the plaques might have been transmitted, alongside the prions, in the injections of growth hormone-the first evidence that Alzheimer's could be transmitted from one person to another. If true, that could have far-reaching implications: the possibility that 'seeds' of the amyloid-β protein involved in Alzheimer's could be transferred during other procedures in which fluid or tissues from one person are introduced into another, such as blood transfusions, organ transplants and other common medical procedures.

Six years ago, Yale University's Stephen Stearns and colleagues took advantage of a long-running study in Framingham, Massachusetts, to assess whether the effects of natural selection could be discerned among the people in the multigenerational study population. Over the last seven decades, public-health researchers have been monitoring the residents of Framingham, noting their vital statistics as well as blood sugar and cholesterol levels to understand the factors that lead to heart disease. As the initial group of research subjects got older, the study started to include their children, and then their grandchildren. The records provide a unique view of the health of a segment of the American population since 1948.

This interrupted case study examines molecular genetic evidence reported in scientific literature to determine the fate of Louis-Charles, son of Louis XVI and Marie-Antoinette of France. Controversy and rumors surrounding the death of Louis-Charles suggested that either he died as a young boy while being held in captivity by the French revolutionaries or he escaped and was replaced by a substitute who died in his place. One individual claiming to be Louis-Charles was Karl Naundorff. Students begin the case by preparing pedigrees for the descendants of Maria Theresa and Francis I, the Holy Roman Emperor, parents of Marie-Antoinette. The pedigrees can be used to introduce the concepts of alleles identical-by-descent and cytoplasmic inheritance patterns. Students then compare mitochondrial DNA sequences and XY chromosome sequences from hair, bone, heart, and blood samples taken from descendants of Marie Theresa, Karl Naundorff and the heart of the boy who died in captivity to determine if the latter was truly Louis-Charles. An optional PowerPoint presentation with clicker questions is available to help guide the classroom activities.

Inflammation may help you fight off invading microbes, but it can also kill you, leading to insufficient blood flow and even organ failure. A new study shows that some cancer drugs may be able to quell the excessive inflammation that occurs in conditions such as sepsis, which is responsible for more than 250,000 deaths in the United States each year.

Blood vessel growth-or angiogenesis-is critical for developing fetuses and to heal wounds. But it is also an essential element of how cancerous tumors grow and spread. Here, see a step-by-step explanation of how the process works and how anti-angiogenesis therapies might stop tumors before they become deadly.

Stem Cell Overview Article with embedded Video 7:53 Discusses gene expression/differentiation 2 minute segments -Pluripotent stem cells in early embryo CDX2 OCT3/4, Inner cell mass start- 1:50 - Characteristics of Stem Cells: differentiation, abilities of stem cells,  1:55- 3:17 - Stem Cells in the Adult Body: red blood cell hematopoetic stem cells, differentiation, small intestine crypts,  3:20-5:35 - Embryonic Stem Cells in Culture: ES pluripotent cells ES cells, treat to neural lineages, culture conditions, study differentiate into lineages 5:40- 7:53

In a north London hospital, scientists are growing noses, ears and blood vessels in the laboratory in a bold attempt to make body parts using stem cells.

Chinese scientists say they've genetically modified human embryos for the very first time. The team attempted to modify the gene responsible for beta-thalassaemia, a potentially fatal blood disorder, using a gene-editing technique known as CRISPR/Cas9. Gene editing is a recently developed type of genetic engineering in which DNA is inserted, replaced, or removed. Here, experts weigh-in with ethical questions and considerations.

"The Inner Life of a Cell, an 3 animation created in NewTek LightWave 3D and Adobe After Effects for Harvard biology students. The animation illustrates unseen molecular mechanisms and the ones they trigger, specifically how white blood cells sense and respond to their surroundings and external stimuli."

In 1674, Antonie van Leeuwenhoek looked at a drop of lake water through his homemade microscope and discovered an invisible world that no one knew existed. His work inspired countless microbiology researchers, including HHMI investigator Bonnie Bassler, one of the narrators of this animated feature. Leeuwenhoek was a haberdasher and city official in Delft, The Netherlands. He started making simple microscopes and using them to observe the world around him. He was the first to discover bacteria, protists, sperm cells, blood cells, rotifers, and much more. 

The activity of some of our genes varies with the seasons throughout the year. The discovery comes from an analysis of blood samples from more than 16,000 people in both hemispheres. The most striking pattern was that 147 genes involved in the immune system made it more reactive or "pro-inflammatory" during winter or rainy seasons, probably to battle the onslaught of cold and flu viruses

Everyone hates mosquitos. Besides the annoying buzzing and biting, mosquito-borne diseases like malaria kill over a million people each year (plus horses, dogs and cats). And over the past 100 million years, they've gotten good at their job -- sucking up to three times their weight in blood, totally undetected. So shouldn't we just get rid of them? Rose Eveleth shares why scientists aren't sure.

Existing mouse models of lethal Ebola virus infection do not reproduce hallmark symptoms of Ebola hemorrhagic fever, neither delayed blood coagulation and disseminated intravascular coagulation, nor death from shock, thus restricting pathogenesis studies to non-human primates. Here we show that mice from the Collaborative Cross exhibit distinct disease phenotypes following mouse-adapted Ebola virus infection. Phenotypes range from complete resistance to lethal disease to severe hemorrhagic fever characterized by prolonged coagulation times and 100% mortality. Inflammatory signaling was associated with vascular permeability and endothelial activation, and resistance to lethal infection arose by induction of lymphocyte differentiation and cellular adhesion, likely mediated by the susceptibility allele Tek. These data indicate that genetic background determines susceptibility to Ebola hemorrhagic fever.

Components of the immune system called antibodies are found in the liquid portion of blood and help protect the body from harm. Antibodies can also be used outside the body in a laboratory-based assay to help diagnose disease caused by malfunctions of the immune system or by infections.

Neutrophils are our body's first line of defense against bacterial infections. After leaving nearby blood vessels, these cells recognize chemicals produced by bacteria in a cut or scratch and migrate "toward the smell". The above neutrophils were placed in a gradient of fMLP (n formyl methionine- leucine- phenylalanine), a peptide chain produced by some bacteria. The cells charge out like a "posse" after the bad guys.