Zombie ant jack o' lantern

In the spirit of Halloween, we’ve asked Dr. David Hughes of Penn State University and  Dr. Harry Evans of  Federal University of Viçosa Brazil to share with us a bit about their manuscript, Hidden Diversity Behind the Zombie-Ant FungusOphiocordyceps unilateralis: Four New Species Described from Carpenter Ants in Minas Gerais, Brazil.   Both were kind enough to oblige and share with us their perspective via email.

The description of ants as zombies is not a pitch to popularity-even at Halloween-  but an orchestrated attempt to identify fungal-infected ants as very different from other ants in the society. Just because something looks, walks and quacks like a duck doesn’t mean it is actually a duck. The sinister thing about parasites which manipulate host behavior is that they can easily go unnoticed. The zombie ant moniker forces us to recall that we are looking at two organisms and the ant is not in the driving seat.

Our study in PLoS ONE, which used micromorphology together with spore function to delimit and describe new species, came about as it was obvious that the diversity of zombie ant fungi must be  higher than previously supposed because ant species diversity is high. We know that ants differ in many important behaviors which of course is due to brain differences. So, if your evolutionary gambit is brain control, then diverse brains will act as diverse selection environments leading to different species. Perhaps the most exciting thing is that we now recognize that these initial descriptions are just the tip of a very large iceberg and that many more zombie-inducing fungi await discovery, especially in tropical forests such as the Brazilian Atlantic rainforest in which we set our study.

In March, our editor wrote an overview of this paper.  To see last year’s Halloween post, click here.

Image by Roel Fleuren and pumpkin carving by Charissa de Bekker.

This post was written by Caroline McCormick, who started at PLoS ONE last year as a Publications Assistant and is now a Publications Manager. She focuses on ethics queries and managing projects related to the editorial process.

This week’s featured image comes from the paper “Lymnaea schirazensis, an Overlooked Snail Distorting Fascioliasis Data: Genotype, Phenotype, Ecology, Worldwide Spread, Susceptibility, Applicability.”
These snails are known to transmit trematodes that cause pathogenic liver parasitosis in humans and animals, and the authors spent 10 years collecting snails in 4 different continents in order study the link between the snails and the fascioliasis associated with them.

The authors determined that while the snails are geographically diverse, they are genetically similar, and they provide both a thorough genetic analysis and a brief history of this pathogen’s trip around the world.

Background

Lymnaeid snails transmit medical and veterinary important trematodiases, mainly fascioliasis. Vector specificity of fasciolid parasites defines disease distribution and characteristics. Different lymnaeid species appear linked to different transmission and epidemiological patterns. Pronounced susceptibility differences to absolute resistance have been described among lymnaeid populations. When assessing disease characteristics in different endemic areas, unexpected results were obtained in studies on lymnaeid susceptibility to Fasciola. We undertook studies to understand this disease transmission heterogeneity.

Methodology/Principal Findings

A ten-year study in Iran, Egypt, Spain, the Dominican Republic, Mexico, Venezuela, Ecuador and Peru, demonstrated that such heterogeneity is not due to susceptibility differences, but to a hitherto overlooked cryptic species, Lymnaea schirazensis, confused with the main vector Galba truncatula and/or other Galba/Fossaria vectors. Nuclear rDNA and mtDNA sequences and phylogenetic reconstruction highlighted an old evolutionary divergence from other Galba/Fossaria species, and a low intraspecific variability suggesting a recent spread from one geographical source. Morphometry, anatomy and egg cluster analyses allowed for phenotypic differentiation. Selfing, egg laying, and habitat characteristics indicated a migration capacity by passive transport. Studies showed that it is not a vector species (n = 8572 field collected, 20 populations): snail finding and penetration by F. hepatica miracidium occur but never lead to cercarial production (n = 338 experimentally infected).

Conclusions/Significance

This species has been distorting fasciolid specificity/susceptibility and fascioliasis geographical distribution data. Hence, a large body of literature on G. truncatula should be revised. Its existence has henceforth to be considered in research. Genetic data on livestock, archeology and history along the 10,000-year post-domestication period explain its wide spread from the Neolithic Fertile Crescent. It is an efficient biomarker for the follow-up of livestock movements, a crucial aspect in fascioliasis emergence. It offers an outstanding laboratory model for genetic studies on susceptibility/resistance in F. hepatica/lymnaeid interaction, a field of applied research with disease control perspectives.

A photographic series covering 5, 15 and 25 years of sessile structural species dwelling on Mediterranean coralligenous outcrops is  this week’s featured image.

This brilliant figure contains frames with sponge and anthozoan species used in the paper, Low Dynamics, High Longevity and Persistence of Sessile Structural Species Dwelling on Mediterranean Coralligenous Outcrops.

In the Abstract the authors write:

Background:

There is still limited understanding of the processes underlying benthic species dynamics in marine coastal habitats, which are of disproportionate importance in terms of productivity and biodiversity. The life-history traits of long-lived benthic species in these habitats are particularly poorly documented. In this study, we assessed decadal patterns of population dynamics for ten sponge and anthozoan species that play key structural roles in coralligenous outcrops (~25 m depth) in two areas of the NW Mediterranean Sea.

Methodology/Principle Findings:

This study was based on examination of a unique long-term photographic series, which allowed analysis of population dynamics over extensive spatial and time spans for the very first time. Specifically, 671 individuals were censused annually over periods of 25-, 15-, and 5-years. This long-term study quantitatively revealed a common life-history pattern among the ten studied species, despite the fact they present different growth forms. Low mortality rates (3.4% yr⁻¹ for all species combined) and infrequent recruitment events (mean value of 3.1±0.5 SE recruits yr⁻¹) provided only a very small fraction of the new colonies required to maintain population sizes.

Conclusions:

Overall, annual mortality and recruitment rates did not differ significantly among years; however, some species displayed important mortality events and recruitment pulses, indicating variability among species. Based on the growth rates of these 10 species, we projected their longevity and, obtained a mean estimated age of 25–200 years. Finally, the low to moderate turnover rates (mean value 0.80% yr⁻¹) observed among the coralligenous species were in agreement with their low dynamics and persistence. These results offer solid baseline data and reveal that these habitats are among the most vulnerable to the current increases of anthropogenic disturbances.

This post was written by Raquel Iglesias, a publications assistant at PLoS ONE .  Raquel has been assisting authors, reviewers and academic editors since April of last year.  She also helps ensure our clinical trial submissions move through the review process smoothly.

Researchers find a possible cure for the common cold and more – in this week’s media digest.

Human Pathogen Shown to Cause Disease in the Threatened Eklhorn Coral Acropora palmata was covered by The NewsHour, The New York Times, NPR, and CNN.

CNET, Hindustan Times, and Okezone covered Automatic Prediction of Facial Trait Judgments: Appearance vs. Structural Models.

The paper, Predator Cat Odors Activate Sexual Arousal Pathways in Brains of Toxoplasma gondii Infected Rats, received coverage from The New York Times, Scientific American, TIME’s Healthland, and The Loom.

Broad-Spectrum Antiviral Therapeutics received media coverage from Voice of America, LA Times, and Forbes.

Large Recovery of Fish Biomass in a No-Take Marine Reserve was covered by National Geographic (nice slideshow too), The Christian Science Monitor, Nature News, and KGTV San Diego. The image above, is taken from Figure 4 of this manuscript.

80 Beats covered the article, Artificial Skin – Culturing of Different Skin Cell Lines for Generating an Artificial Skin Substitute on Cross-Weaved Spider Silk Fibres. So did Treehugger.

The article entitled, Scientists Want More Children received media coverage from The Wall Street Journal, TIME’s Ecocentric, Science Career Blog, and Inside Higher Ed.

Elevated Non-Esterified Fatty Acid Concentrations during Bovine Oocyte Maturation Compromise Early Embryo Physiology was covered by Reuters, The Guardian, and The Press Association.

In the abstract, the authors write:

Background

Understanding the mechanisms underlying biological phenomena, such as evolutionarily conservative trait inheritance, is predicated on knowledge of the natural relationships among organisms. However, despite their enormous ecological significance, many of the ubiquitous soil inhabiting and plant symbiotic arbuscular mycorrhizal fungi (AMF, phylum Glomeromycota) are incorrectly classified.

Methodology/Principal Findings

Here, we focused on a frequently used model AMF registered as culture BEG47. This fungus is a descendent of the ex-type culture-lineage of Glomus epigaeum, which in 1983 was synonymised with Glomus versiforme. It has since then been used as ‘G. versiforme BEG47’. We show by morphological comparisons, based on type material, collected 1860–61, of G. versiforme and on type material and living ex-type cultures of G. epigaeum, that these two AMF species cannot be conspecific, and by molecular phylogenetics that BEG47 is a member of the genus Diversispora.

Conclusions

This study highlights that experimental works published during the last >25 years on an AMF named ‘G. versiforme’ or ‘BEG47’ refer to D. epigaea, a species that is actually evolutionarily separated by hundreds of millions of years from all members of the genera in the Glomerales and thus from most other commonly used AMF ‘laboratory strains’. Detailed redescriptions substantiate the renaming of G. epigaeum (BEG47) as D. epigaea, positioning it systematically in the order Diversisporales, thus enabling an evolutionary understanding of genetical, physiological, and ecological traits, relative to those of other AMF. Diversispora epigaea is widely cultured as a laboratory strain of AMF, whereas G. versiforme appears not to have been cultured nor found in the field since its original description.

All of PLoS ONE’s sporific papers are open access and free for you to read, rate and reuse.

Citation: Schüßler A, Krüger M, Walker C (2011) Revealing Natural Relationships among Arbuscular Mycorrhizal Fungi: Culture Line BEG47 Represents Diversispora epigaea, Not Glomus versiforme. PLoS ONE 6(8): e23333. doi:10.1371/journal.pone.0023333

This week’s featured image comes from the manuscript, Tradeoff between Stability and Maneuverability during Whole-Body Movements by Drs. Alaa Ahmed and Helen Huang at the University of Colorado Boulder.

In the paper, the authors tested if a person’s maneuverability comes at the expense of his or her stability.  Standing on a balancing board, the subjects were asked to lean forward and use their center of pressure (CoP) to move a cursor toward a target on a computer monitor. The image above (Figure 1) illustrates the set-up and protocol of this experiment.

From the abstract:

Background

Understanding how stability and/or maneuverability affects motor control strategies can provide insight on moving about safely in an unpredictable world. Stability in human movement has been well-studied while maneuverability has not. Further, a tradeoff between stability and maneuverability during movement seems apparent, yet has not been quantified. We proposed that greater maneuverability, the ability to rapidly and purposefully change movement direction and speed, is beneficial in uncertain environments. We also hypothesized that gaining maneuverability comes at the expense of stability and perhaps also corresponds with decreased muscle coactivation.

Materials and Methods

We used a goal-directed forward lean movement task that integrated both stability and maneuverability. Subjects (n = 11) used their center of pressure to control a cursor on a computer monitor to reach a target. We added task uncertainty by shifting the target anterior-posterior position mid-movement. We used a balance board with a narrow beam that reduced the base of support in the medio-lateral direction and defined stability as the probability that subjects could keep the balance board level during the task.

Results

During the uncertainty condition, subjects were able to change direction of their anterior-posterior center of pressure more rapidly, indicating that subjects were more maneuverable. Furthermore, medio-lateral center of pressure excursions also approached the edges of the beam and reduced stability margins, implying that subjects were less stable (i.e. less able to keep the board level). On the narrow beam board, subjects increased muscle coactivation of lateral muscle pairs and had greater muscle activity in the left leg. However, there were no statistically significant differences in muscle activity amplitudes or coactivation with uncertainty.

Conclusions/Significance

These results demonstrate that there is a tradeoff between stability and maneuverability during a goal-directed whole-body movement. Tasks with added uncertainty could help individuals learn to be more maneuverable yet sufficiently stable.

Citation: Huang HJ, Ahmed AA (2011) Tradeoff between Stability and Maneuverability during Whole-Body Movements. PLoS ONE 6(7): e21815. doi:10.1371/journal.pone.0021815

This week’s featured image comes from a paper by Frank DiMaio et al. entitled, Modeling Symmetric Macromolecular Structures in Rosetta3.

Most homomeric protein assemblies are symmetric and the authors of this paper use Rosetta 3 to implement “a general framework for modeling arbitrary symmetric systems.”  The figure above illustrates a variety of symmetry groups found in the Protein Data Bank.

From the abstract:

Symmetric protein assemblies play important roles in many biochemical processes. However, the large size of such systems is challenging for traditional structure modeling methods. This paper describes the implementation of a general framework for modeling arbitrary symmetric systems in Rosetta3. We describe the various types of symmetries relevant to the study of protein structure that may be modeled using Rosetta’s symmetric framework. We then describe how this symmetric framework is efficiently implemented within Rosetta, which restricts the conformational search space by sampling only symmetric degrees of freedom, and explicitly simulates only a subset of the interacting monomers. Finally, we describe structure prediction and design applications that utilize the Rosetta3 symmetric modeling capabilities, and provide a guide to running simulations on symmetric systems.

To celebrate publication of their recent research, “Mitotic Spindle Proteomics in Chinese Hamster Ovary Cells,” Dr. Ahna Skop, whose second passion is food, baked a batch of fudgy chocolate cupcakes topped with mocha ganache and decorated them with isolated mitotic spindles inspired by those in Figure 2 of the article. Here is Dr. Skop’s summary of the research:

Segregation of genetic material is indispensible for the propagation of all species. Each cell relies on a dynamic microtubule-based machine called the mitotic spindle to facilitate the cell division process. Failures in mitosis can lead to birth defects, various leukemias, and tissue-specific tumors, suggesting that knowledge of the molecular make-up of the mitotic spindle is central to our understanding of a variety of human diseases. To identify new proteins that comprise the mitotic spindle, we subjected isolated mitotic spindles to Multi-dimensional Protein Identification Technology (MudPIT) analysis and tandem mass spectrometry. We identified 1155 proteins, which represent the largest number of spindle-associated proteins identified to date. Our initial protein profile of mitosis has implications for cancer research, as major spindle components have been identified as targets for cancer therapeutics.

Seen below Figure 2, the cupcakes provide a beautiful, and delicious, depiction of isolated mitotic spindles, especially similar to those stained green in Figure 2 (A). If you would like to bake mitotic spindle cupcakes at home, the recipe can be found on Dr. Skop’s blog. Yum!

The paper, Propagation of Respiratory Aerosols by the Vuvuzela, investigates whether this instrument could aide in the spread of airborne disease. Figure 1 of the manuscript (shown above) is an illustration of the setup of the vuvuzela and shouting experiments.

From the abstract:

Vuvuzelas, the plastic blowing horns used by sports fans, recently achieved international recognition during the FIFA World Cup soccer tournament in South Africa. We hypothesised that vuvuzelas might facilitate the generation and dissemination of respiratory aerosols. To investigate the quantity and size of aerosols emitted when the instrument is played, eight healthy volunteers were asked to blow a vuvuzela. For each individual the concentration of particles in expelled air was measured using a six channel laser particle counter and the duration of blowing and velocity of air leaving the vuvuzela were recorded. To allow comparison with other activities undertaken at sports events each individual was also asked to shout and the measurements were repeated while using a paper cone to confine the exhaled air. Triplicate measurements were taken for each individual. The mean peak particle counts were 658×10³ per litre for the vuvuzela and 3.7×10³ per litre for shouting, representing a mean log₁₀ difference of 2.20 (95% CI: 2.03,2.36; p<0.001). The majority (>97%) of particles captured from either the vuvuzela or shouting were between 0.5 and 5 microns in diameter. Mean peak airflows recorded for the vuvuzela and shouting were 6.1 and 1.8 litres per second respectively. We conclude that plastic blowing horns (vuvuzelas) have the capacity to propel extremely large numbers of aerosols into the atmosphere of a size able to penetrate the lower lung. Some respiratory pathogens are spread via contaminated aerosols emitted by infected persons. Further investigation is required to assess the potential of the vuvuzela to contribute to the transmission of aerosol borne diseases. We recommend, as a precautionary measure, that people with respiratory infections should be advised not to blow their vuvuzela in enclosed spaces and where there is a risk of infecting others.

To mark this occasion, we’ve asked Dr. Brian Oliver and Dr. Stephen Liggett, authors of the 20,000^th manuscript, b2-Agonist Induced cAMP Is Decreased in Asthmatic Airway Smooth Muscle Due to Increased PDE4D to tell us a bit about their article, their background, and their research via email.

To begin, give us a summary of your research?

Dr. Brian Oliver

BO: In our research, we have been examining how the drugs, which relax bronchial air passages of people with asthma, work.  These therapies bind to, and activate the ß2 receptor. This receptor induces the formation of cAMP, which initiates muscle relaxation.  In turn cAMP is regulated by an enzyme phosphodiesterase 4 (PDE4D).  We have discovered that airway smooth muscle cells from people with asthma have increased phosphodiesterase 4.  As phosphodiesterase 4 degrades cAMP, our research has important implications for the treatment of asthma.

SL: We found that airway smooth muscle cells derived from asthmatics are “hard-wired” to have a defect in signaling by the beta-2 adrenergic receptor. This defect is an enhanced phosphodiesterase activity, essentially leading to rapid metabolism of intracellular cAMP, rendering the asthmatic smooth muscle cell with a depressed response to beta-agonists. Beta-agonists are the major drugs used to relax airway smooth muscle and open airways in asthma. The hard-wiring part is quite intriguing. It has been generally thought that inflammation in asthma leads to signaling defects, at both the relaxation side (such as with beta-2 adrenergic receptors) and the exaggerated bronchoconstrictive receptors such as the M3 muscarinic receptor. However, these cells were kept in cell culture media and passaged multiple times, and obviously removed from the inflammatory environment in the asthmatic patients. So, this is either a genetic or epigenetic effect.

When did you become interested in studying asthma?

BO: Before starting my PhD, I realized that asthma is a disease which effects a large proportion of the population (at least 10%), and is also a disease in which there is a need to develop better therapeutics.  I was fortunate to be employed at the National Heart and Lung Institute,UK where I examined basic science mechanisms underpinning asthma, and I realized that this is where my future career would be.  I then travelled to Australia to undertake my PhD with Professor Judith Black who is one of the leading experts in airway smooth muscle biology, and as they say I have never looked back.

SL: I was a post doc at the HHMI with Robert Lefkowitz during the cloning and initial characterization of the adrenergic receptors, and my lab studies basic structure/function relationships. But I have always been drawn to the translational aspect of understanding how G-protein coupled receptor signaling is so aberrant in asthma. And, I have persistent asthma myself, so there is a personal interest in further understanding these issues. Actually, I am wondering if this has been a driving force for longer than I might realize. I got irritated that we knew so little about human rhinoviruses (a major cause of asthma exacerbations), so we just sequenced every known common cold strain to get a handle on that. And we have made dozens of transgenic mice aimed at understanding smooth muscle signaling, all pointing towards asthma. So as it was with this study, we went against some old dogma and just pushed on. Studying human cells derived from affected and unaffected individuals is hard, but it must be done if we are to crack this nut.

Your manuscript has several figures in it. Which one do you think is the most important for people to pay attention too?

BO: Figure one represents the initial finding which led to this study, however this for me is not the most important figure.  Figure two is.  In figure two we measured phosphodiesterase activity in asthmatic airway smooth muscle cells, and found increased activity in the asthmatic cells.  To investigate which phosphodiesterase was increased we used a series of phamalogical inhibitors and were able to demonstrate that PDE4 activity was specifically increased in the asthmatic cells.

During the course of your research for this paper, did you find anything unexpected?

BO: Our initial finding was that ß2 agonist induced cAMP was lower in the asthmatic cells.  There are several reasons described in the literature as to why this could occur.  However increased PDE4 activity was not one of these.

SL: The hard-wiring aspect, and where the defect was. I figured that it would be upstream of adenylyl cyclase.

What’s next? Where would you like to go from here?

Dr. Stephen B Liggett

BO: In asthma, virus infection precipitates exacerbations (bronchial contraction) in which ß2 agonist don’t work as well as they do at other times.  As we have now shown that PDE4 activity is increased in asthma we want to investigate the role of PDE4 in virus-induced exacerbations.

SL: Now that we have this identified, we would like to devise a “workaround” strategy, that will allow for effective bronchial dilatation by beta-agonists (or another receptor), so as to provide more effective treatments.

What made you decide to submit to PLoS ONE?

BO: There are several factors to consider when submitting a paper to a journal.  Amongst the most important are: journal prestige, length of review process, and the accessibility of the paper post publication.  PLoS ONE is a good journal by all measures, and based upon our previous experience we knew that we would receive a quick and fair review.  Also, being open access allows anyone with internet access to see our paper and, as such, allows us as scientists to share our findings with the world.

SL: The general readership is a big plus. As we all know so well, these pathways and proteins are in many cell types and we wanted investigators from many fields to be aware of what we found, so that there can be more “collective thinking.”