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In nature, color can be imparted to a feature either by a pigment or a structure that selectively reflects a part of the visible spectrum. The latter is called structural color, and it may be brighter than a pigment. Structural color is often used by animals for signaling, mimicry, and/or mate choice. In plants, mainly fruits, structural color is probably used for mimicry. Silvia Vignolini, Paula Rudall, Alice Rowland, Alison Reed, Edwidge Moyroud, Robert Faden, Jeremy Baumberg, Beverley Glover, and Ullrich Steiner described the anatomical arrangement within the outer layers (epicarp) of a blue fruit found in equatorial Africa that results in a blue color more intense than that of any previously described biological material! Although this fruit (Figure 1) has no nutritional value, by imitating the appearance of a fresh nutritious fruit, it avoids the energy cost of producing pulp yet can be dispersed by birds. And not only can it imitate a food source, it is probably also dispersed by birds who use it to decorate their nests in order to attract mates.
The rocky intertidal zone is an extreme environment with high, variable forces from crashing waves and strong ocean currents. A family of fishes, including the northern clingfish (Gobiesox maeandricus), has evolved an adhesive disc that allows them to adhere to rocks in the intertidal zone and even launch predatory attacks on molluscs that are attached to the rocks (Figure 1). Dylan Wainwright, Thomas Kleinteich, Anja Kleinteich, Stanislav Gorb, and Adam Summers studied the morphology of this fish disc to understand the properties of a reversibly adhesive disc that has a strong tenacity to stick to irregular, slippery, and wet surfaces.
Localizing specific proteins within cells, tissues, and organisms has been a goal of microscopists for generations. In the early 1990s, a breakthrough was made when a molecule originally derived from a jellyfish was introduced as a probe for fluorescence microscopy. This molecule is green fluorescent protein (GFP), and it has become well known for its usefulness in localizing proteins at the level of the light microscope. It is also well known that electron microscopy (EM) offers far superior spatial resolution over light microscopy, but the application of probes to localize specific proteins has required antibodies conjugated with colloidal metals (such as gold). Delivery of antibodies into the cell commonly requires detergents to permeabilize the cell membrane, which compromises the ultrastructural detail. Another breakthrough was recently published on-line by Xiaokun Shu, Varda Lev-Ram, Thomas Deerinck, Yingchuan Qi, Ericka Ramko, Michael Davidson, Yishi Jin, Mark Ellisman, and Roger Tsien: they have developed a method similar to using GFP for light microscopy, but for specifically tagging proteins at the EM level.
It has been known for decades that clathrin- and dynamin-mediated endocytosis is the major pathway for recycling the components of vesicle membranes after strong stimulation and high rates of exocytosis in secretory cells. This pathway occurs over tens of seconds to minutes after fusion of the secretory vesicle membrane with the plasma membrane. It resembles classical receptor-mediated endocytosis, but it has a trigger that is unique to secretion: the sudden appearance of the secretory vesicle membrane on the surface of the cell. However, the spatial localization, the relationship to individual fusion events, the nature of the cargo, and the timing and nature of nucleation events have been unknown. An elegant study by Mary Bittner, Rachel Aikman, and Ronald Holz has addressed these issues.
High-density magnetic memory is typically fabricated from ferromagnetic materials. As the density is increased and the memory elements are more densely packed, the magnetic fields of neighboring elements interfere with each other. If materials without magnetic fields, referred to as antiferromagnetic, could be manipulated to store data, such limitations theoretically could be overcome. In a breakthrough study, Sebastian Loth, Susanne Baumann, Christopher Lutz, Don Eigler, and Andreas Heinrich used a low-temperature scanning tunneling microscope (STM) to assemble a device with just 12 antiferromagnetic atoms that could be manipulated to one of two states, demonstrating the ability to store data. Until now, about one million atoms have been required to store a digital 0 or 1 in the most advanced magnetic storage systems.
About 40,000 to 30,000 years ago, modern humans out-competed Neanderthals, and the Neanderthals became extinct. Some recent theories have speculated that Neanderthals had an inferior diet (predominately meat) that put them at a disadvantage. Evidence for plant foods is rare at sites occupied by Neanderthals, but this could be due to vagaries of preservation and insufficient attention to plant remains. In an ingenious study, Amanda Henry, Alison Brooks, and Dolores Piperno used microscopy to demonstrate that plants and cooked foods are present in dental calculus (the stuff the dental hygienist scrapes off your teeth) on the teeth of Neanderthals.
An important challenge in microscopy is the development of high-resolution light microscopy methods to label and image cell populations in three dimensions. The ability to achieve this deep into intact specimens is limited by light scattering. Modern technologies, such as two-photon excitation fluorescence microscopy, allow examination of structures at distances of hundreds of micrometers below the surface but are insufficient to image and reconstruct large cell populations that are millimeters in scale and deeper below the surface. Whereas light scattering can be reduced by optical clearing, most of these reagents exhibit limitations such as the quenching of fluorescence. Recently, a clearing agent that spectacularly alleviates these major limitations was developed by Hiroshi Hama, Hiroshi Kurokawa, Hiroyuki Kawano, Ryoko Ando, Tomomi Shimogori, Hisayori Noda, Kiyoko Fukami, Asako Sakaue-Sawano, and Atsushi Miyawaki. They developed a clearing reagent called Scale that renders mouse brains and embryos transparent while completely preserving fluorescent signals from labeled cells!
Of the winged insects, adults have one or two pairs of wings. During the past 250 million years of insect evolution, there have been no exceptions to this. In a fascinating study, Benjamin Prud'homme, Caroline Minervino, Mélanie Hocine, Jessica Cande, Aïcha Aouane, Héloïse Dufour, Victoria Kassner, and Nicolas Gompel may have found something resembling an exception.
Since transmission electron microscopy (TEM) was developed about 80 years ago, numerous strategies have been attempted to visualize living cells at high resolution. The harsh environment within the TEM (mostly the vacuum and damage from a fixed beam of electrons) presents challenges. Some approaches have been to fabricate chambers within the TEM that provide a more “friendly” environment for living cells (that is, less stringent vacuum), but they have limitations. Impressive images have been generated with various cryogenic techniques, but frozen cells are not alive or in their native state in the traditional sense. Nihar Mohanty, Monica Fahrenholtz, Ashvin Nagaraja, Daniel Boyle, and Vikas Berry have developed an ingenious solution to the problem by “wrapping” cells with modified graphene.
Perhaps you've never wondered what sounds permeated the nighttime in a Jurassic forest, but there is now a partial answer. With the good fortune to obtain a well-preserved fossil specimen, Jun-Jie Gu, Fernando Montealegre-Z, Daniel Robert, Michael Engel, Ge-Xia Qiao, and Dong Ren were able to reconstruct the sounds that would have been made by a katydid of that geologic time.