American Scientist

In this roundup, Katie Burke summarizes notable recent items about scientific research, selected from news reports compiled in the free electronic newsletter Sigma Xi SmartBrief.

Overcoming Uncertainty

One key point of Heisenberg’s Uncertainty Principle states that measuring properties of a quantum system disturbs it; thus only parts of a system can be studied at any given time. For example, when light is polarized, or the light’s electromagnetic wave is oriented in multiple directions, measuring the vertical-horizontal polarization will damage information about the diagonal-antidiagonal polarization. Researchers have directly measured these properties all at once for the first time. They measured polarized light’s wavefunction, a fundamental property of a quantum system that indicates the state and behavior of a particle. By sneaking quick measurements of the system, they “weakly” measured one polarization before taking a “strong” measurement of the other. Collecting the “weak” information little by little, they accrued the amount necessary to be confident in those measurements. Because this information is binary (horizontal-vertical or diagonal-antidiagonal), this new technique could be applied to quantum computing technology.

Salvail, J. Z., et al. Full characterization of polarization states of light via direct measurement. Nature Photonics (Published online March 3)

Busy, Caffeinated Bees

Flowering plants compete for available pollinators; thus evolution has favored flowers that are attractive to pollinators in scent, taste and looks. Small concentrations of caffeine occur naturally in flower nectar of plants in the genera Coffea and Citrus. A recent study shows that caffeine helps plants gain a competitive edge in pollinator visits. Bees were twice as likely to remember the scent of a flower and revisit it, compared to their revisitation rate without caffeine. The chemical caused this response by interacting with neuronal receptors associated with olfactory learning and memory.

Wright, G. A., et al. Caffeine in floral nectar enhances a pollinator’s memory of reward. Science 339:1202 (March 8)

Please Pass on the Salt

Over the past few decades, the prevalence of autoimmune diseases has increased. Recent work has implicated certain genes’ roles in such diseases, but genetics cannot exclusively explain this increase, indicating that environmental factors are involved. Certain types of immune cell are associated with autoimmune diseases, such as inflammatory bowel disease and multiple sclerosis. One culprit is the T_H17 cell, which develops from unspecialized white blood cells called T cells and can become helpful or harmful. Noticing that people who ate more fast food also had higher levels of T_H17 cells, researchers postulated that this trend could be due to their high-salt diet. Recent studies on mice and on cultured cells indicate that salt indeed is involved with high levels of T_H17. Adding salt to cultures of unspecialized T cells induced 10 times the amount of harmful, inflammatory T_H17 cell maturation. As further support, mice fed high-salt meals developed the mouse-model equivalent of multiple sclerosis sooner and with more severe symptoms than those fed a low-salt diet. In a separate study, researchers studied pathways associated with T_H17 maturation. One of the lynchpin genes in the pathway stimulating T_H17 production, called SGK1, has a receptor for salt. A third study found that adding salt to T-cell cultures incited T_H17 specialization through SGK1. The stage is set for further research to corroborate the link between salt and human autoimmune disease.

Kleinewietfeld, M., et al. Sodium chloride drives autoimmune disease by the induction of pathogenic T_H17 cells. Nature (Published online March 6)

Wu, C., et al. Induction of pathogenic T_H17 cells by inducible salt-sensing kinase SGK1. Nature (Published online March 6)

Yosef, N., et al. Dynamic regulatory network controlling T_H17 cell differentiation. Nature (Published online March 6)

HIV Sting Operation

A bee’s sting injects venom containing a toxin called melittin. A recent study demonstrated melittin’s potential to destroy the HIV virus by breaking up its protective envelope. In laboratory experiments, researchers surrounded the toxin with nanoparticles that kept it from interacting with human cells in culture; however, spaces between the nanoparticles were large enough that melittin could interact with the virus, which is much smaller than human cells. Most anti-HIV drugs prevent the virus’s replication but not initial infection. The authors plan to explore the potential for nanoparticle-delivered melittin’s use in a vaginal gel that could prevent initial infection. This method also has potential for treating those already infected with HIV or with other viruses.

Hood, J. L., A. P. Jallouk, N. Campbell, L. Ratner and S. A. Wickline. Cytolytic nanoparticles attenuate HIV-1 infectivity. Antiviral Therapy 18:95 (February 21)

Bat News

Bats host many high-profile viruses that can infect humans, including severe acute respiratory syndrome and Ebola. A recent study explored the ecological variables that may contribute to bats’ propensity to harbor such zoonotic diseases by comparing them with another order of common reservoir hosts: rodents. The analysis found that although there are more rodent species and thus more zoonotic diseases harbored by rodents in general, bats harbor more zoonotic diseases per species. They found that species with a wide range that overlapped more with other species in the same order (other bats or other rodents, respectively) were more likely to host zoonotic disease. This relationship was stronger in bats than rodents, which could indicate that bats have higher rates of disease transmission between species than rodents do. The authors stress the importance of developing a predictive framework for identifying emerging disease reservoirs.

Luis, A. D., et al. A comparison of bats and rodents as reservoirs of zoonotic viruses: Are bats special? Proceedings of the Royal Society B 280:20122753 (April 7)