The Hawkmoth Manduca sexta is an emerging model system for a wide range of studies in integrative biology. The flight muscles are particularly interesting in that, unlike most insect flight muscle, but like vertebrate skeletal and cardiac muscles, they are a synchronous muscle where each stimulus generates one muscle twitch. The length tension curve also shows intriguing similarities to mammalian cardiac muscle even though the sarcomere structure is known to be quite different. Another property of the muscle is that the dorsal-most region of the flight muscle is ca. 5 degrees C cooler than the ventral muscle closer to the midline to the body. (Such spatial temperature gradients are also likely to occur in large muscles in mammals but this has not been well investigated). In Manduca flight muscle these spatial gradients lead to a spatial variation in power production spanning from positive to negative values across …

In many biological processes, various substances undergo phase transitions, where they are transformed from one state (solid, liquid, or gas) to another. Wiskott-Aldrich Syndrome Proteins (WASP) function as intracellular …

The nucleic acid RNA plays an important role in protein synthesis in cells. However, noncoding RNAs also exist that are not converted into proteins, but still play important roles in many biological processes. RNA molecules aggregate into complex tertiary structures, producing globular forms stabilized by various interactions. Proteins, ligands, and other RNA molecules recognize tertiary folded RNAs and result in the biochemical pathways that affect all aspects of cellular metabolism. Using small-angle X-ray scattering (SAXS) at the …

Flying insects are among the most successful species on our planet. Flight is very metabolically demanding and many insects have found a clever way to reduce energy costs in their flight muscles by employing a process called “stretch activation, which has been recognized since the 1960s as an interesting and physiologically important phenomenon, but a mechanistic explanation has been elusive. Now, research at the Biophysics Collaborative Access Team x-ray facility at the U.S. Department of Energy’s Advanced Photon Source provides another, important step toward a full explanation of stretch activation, which also plays an important role in mammalian cardiac expansion and contraction.

How stretch activation works in the heart is unknown. As contractions propagate through the heart, the contraction of one piece of muscle tissue stretches adjacent muscle, thereby activating it. The end result is a very strong contraction at the end of systole aiding cardiac ejection. Heart muscle is much less organized structurally than insect muscle and is thus …

It’s not stretching the truth to say that flexibility is an important and desirable human physiological trait. We owe our flexibility to a protein called elastin, and elastin derives its properties from a building-block molecule called …

How does one prove that the protein isolated from a 68-million-year-old dinosaur bone is not a contamination from the intervening millenia or from the lab? This is the task of a research team who say they have isolated peptides of the common structural protein, collagen, from bones of Tyrannosaurus rex and Brachylophosauraus canadensis. Although the team had previously presented multiple lines of evidence supporting the veracity of the find, the fact that the age of the peptides far exceeds any previous predictions of how long a protein could resist degradation has generated controversy. In their current work, the researchers used x-ray diffraction data collected utilizing the BioCAT 18-ID x-ray beamline at the U.S. Department of Energy Office of Science’s Advanced Photon Source at Argonne National Laboratory to generate a model of collagen structure on which to overlay the …

Early and correct diagnosis of Alzheimer’s disease (AD) is important for reasons that go beyond correct diagnosis and treatment of symptoms. These reasons include more time to make critical life decisions, planning for future care, and maximizing the safety of the person with Alzheimer’s disease and their family. New scientific results relevant to the diagnosis and treatment of AD have been obtained by researchers utilizing the U. S. Department of Energy’s Advanced Photon Source (APS) at Argonne National Laboratory and National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory, and published in the journal NeuroImage. This work points to the use of elevated brain iron content, already observed in late-stage AD, as a potential tool for early diagnosis. Since the disease is usually diagnosed only in later stages after cognitive symptoms appear and treatment may not be effective, a method for early detection would be a …

Flying insects are among the most successful species on our planet. Flight is very metabolically demanding and many insects have found a clever way to reduce energy costs in their flight muscles by employing a process called “stretch activation,” whereby nervous stimulation is just enough to maintain a constant low level of calcium and the muscles are “turned on” when they are stretched by antagonistic muscles. Stretch activation has been recognized since the 1960s as an interesting and physiologically important phenomenon, but a mechanistic explanation has been elusive. Now, research at the Biophysics Collaborative Access Team (BioCAT) synchrotron x-ray facility at the U.S. Department of Energy’s Advanced Photon Source (APS) at Argonne provides another, important step toward a full explanation of stretch activation, which also plays an important role in mammalian cardiac expansion and contraction.

How stretch activation works in the heart is unknown. As contractions propagate through the heart, the contraction of one piece of muscle tissue …

On average, one hundred billion cells in the human body divide over the course of a day. Most of the time the body gets it right but sometimes problems in cell replication can lead to abnormalities in chromosomes—-resulting in many types of disorders from cancer to Down syndrome. Now, researchers from the University of Pennsylvania School of Medicine (UPSM) have defined the structure of a key molecule that plays a central role in how DNA is duplicated and then moved correctly and equally into two daughter cells to produce two exact copies of the mother cell. Without this molecule, entire chromosomes could be lost during cell division, so this work is a major advance in understanding the molecules driving human genetic inheritance. Two U.S. Department of Energy x-ray light sources, including the Advanced Photon Source (APS) at Argonne National Laboratory, were important tools for the researchers carrying out this study.

The UPSM researchers report, in the September 16, 2010 issue of Nature, the structure …

Nature uses collagen everywhere in constructing multicellular animals. There are at least 20 types of collagen, but 80-90% of the collagen in the body consists of types I, II, and III. Collagen type I is used to form skin, tendon, vascular, ligature, organs, bone, dentin, and interstitial tissues. Collagen type II makes up 50% of all cartilage protein, and is essential in normal formation of such structures as cartilage, the vitreous humor of the eye (the clear gel that fills the space between the lens and the retina of the eyeball of humans and other vertebrates), bones, and teeth. To create these structures, collagen molecules are positioned in arrays called fibrils, producing what are known as the D-periodic fibrillar collagens. Though previous work has given some idea of what the D-periodic structure looks like, technical …