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A blog discussing Mycology and fungi in general. It tends to focus on current journal entries, but does not shy away from interesting pictures of mushrooms or casual entries.
It is official, the chytrid Fungi have reached all three of the extant amphibian orders.Chytrid fungi are the cause of global decimation in frogs and toads, as well as newts and salamanders. But, until now, the lesser known caecilians had managed to evade their mycelial grasp. That ends now!Goodbye Mr. Bond CaecilianA recent study released in the journal EcoHealth has found the first cases of chytridiomycosis in the legless amphibians. Unfortunately, EcoHealth is not a free journal so all I can link you to for the article is the article front page, provided by Springer. You can read the intro but for the full article you gots to have the monies: Batrachochytrium dendrobatidis Infection and Lethal Chytridiomycosis in Caecilian Amphibians (Gymnophiona). But there is also an piece in PsyOrg discussing the Journal article: Fatal fungus found in third major amphibian group, caecilians. The team of researchers conducted a field swab of over 200 specimens across 20 different species in five countries of Africa and South America and ran what amounted to the worlds largest caecilian PCR survey for the presence of Batrachohytrium dendrobatidis, which is the fungi generally refered to as the chytrid fungus. There results? 58 specimens from Tanzania and Cameroon came back positive for it. That is over 25% of the total sample! Infection is a go!But, wait you say, haven't some frogs shown a certain resistance to infection? Could, perhaps, caecilians face fungal morbidity sans mortality? Nope, the team managed to report the first lethal infections as well. Noting that while the degree of infection in the wild samples were not very high, they were at the same levels observed to cause death in Gaboon caecilians held in captivity.So clearly, fungi have completed the dominance over the entire Amphibian Class. Who goes next? Bats? Bees?Well, whichever group it is, I am sure we humans will have our hands full trying to prevent a complete fungal victory.Awesome Reserachers:Gower, D., Doherty-Bone, T., Loader, S., Wilkinson, M., Kouete, M., Tapley, B., Orton, F., Daniel, O., Wynne, F., Flach, E., Müller, H., Menegon, M., Stephen, I., Browne, R., Fisher, M., Cunningham, A., & Garner, T. (2013). Batrachochytrium dendrobatidis Infection and Lethal Chytridiomycosis in Caecilian Amphibians (Gymnophiona) EcoHealth DOI: 10.1007/s10393-013-0831-9 Photo cred: By Franco Andreone - see authorization (http://calphotos.berkeley.edu) [CC-BY-SA-2.5 (http://creativecommons.org/licenses/by-sa/2.5) or CC-BY-SA-2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia CommonsGif props: Arrested Development returns to Netflix on May 26. 2013... Read more »
Gower, D., Doherty-Bone, T., Loader, S., Wilkinson, M., Kouete, M., Tapley, B., Orton, F., Daniel, O., Wynne, F., Flach, E.... (2013) Batrachochytrium dendrobatidis Infection and Lethal Chytridiomycosis in Caecilian Amphibians (Gymnophiona). EcoHealth. DOI: 10.1007/s10393-013-0831-9
We are upon the hour of a new year, which of course means booze! Now, we all know that there will be a medley of alcohols consumed tonight. I am sure that we are also all fully aware that we owe thanks to yeasts, for making that fermentation process so readily available. But not all yeasts want to help with your intoxication. And in the same way they will spoil your good times, those yeasts are called spoilage yeasts.One of the widest spread spoilage yeasts, Zygosaccharomyces bailii, is so successful because it has the ability to tolerate a wide range of stressful living conditions (like fermented products.) While many products like wine, mayonnaise, and even pickles, are generally described to be shelf stable; Z. bailii is ready to get all up in there and have a good time. One of the sweet skills that lead this yeast to be successful is that it can metabolize both glucose, and acetic acid (which is generally seen as a stressor/killer of yeasts.)Zygosaccharomyces bailii wants to ruin your Snakejuice A new study published in the December 28 issue of PLOS One seeks to explore the relationship of Z. bailii’s utilization of these substrates and how it manages to grow efficiently when both are present. Does it utilize both in the same metabolic pathways? Or do the two get consumed separate and independent of one another?The Fate of Acetic Acid during Glucose Co-Metabolism by the Spoilage Yeast Zygosaccharomyces bailiiIn order to determine whether Z. bailii grew more efficiently in the presence of just one substrate or the other, the team grew strains in isolated substrates as well as mixed substrates of Acetic Acid and glucose. Throughout the growth cycle they measured the biomass and compared amongst the cultures. The results of this demonstrated a number of things. When comparing those growth rates and biomass produced on the isolated substrates to those on the mixed substrate cultures, the team found that a mixed growth medium held a lower growth rate at a pH of 3.0 over either pure substrate. This suggests that with the pH lowered the acetic acid affects efficiency, which is evidence of a need by the cell, to overcome intracellular acidification. This is reinforced by the observation that when grown at a higher pH of 5.0 the decrease isn't evident. A similar difference in growth rate is noticed in the purely acetic acid substrate cultures. However; when grown on a mixed substrate of Glucose and acetic acid, Zygosacharomyces bailii utilizes both the acid and sugar simultaneously. The yeast appears to use each of the substrates individually as both a carbon source and an energy source, showing no effect in the presence of the other. This is significant, because generally speaking the presence of glucose reduces the usage of substandard (energy wise) carbon and energy sources.By using magnetic resonance spectroscopy and measuring 14C at various pathway steps, the researchers were able to determine that even when glucose is present, acetic acid will act as an additional source of acetyl-CoA during the Krebs Cycle, as well as for lipid biosynthesis. Basically that means Z. Bailiitakes a typical environmental stressor and uses it to make extra amounts of the precursors for fueling one of the major energy cycles. And thus, your drink and New Year's Eve Bash are destroyed.Awesome Researchers:Rodrigues, F., Sousa, M., Ludovico, P., Santos, H., Côrte-Real, M., & Leão, C. (2012). The Fate of Acetic Acid during Glucose Co-Metabolism by the Spoilage Yeast Zygosaccharomyces bailii PLoS ONE, 7 (12) DOI: 10.1371/journal.pone.0052402Photo Cred:DTDT (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia CommonsGif - Ron Swanson of Parks and Recreation via GIFSoup... Read more »
Rodrigues, F., Sousa, M., Ludovico, P., Santos, H., Côrte-Real, M., & Leão, C. (2012) The Fate of Acetic Acid during Glucose Co-Metabolism by the Spoilage Yeast Zygosaccharomyces bailii. PLoS ONE, 7(12). DOI: 10.1371/journal.pone.0052402
Cordyceps is widely known as the zombie fungus because it likes to take over the brain functions of it victim. Often causing them to do things they normally wouldn't and leading to their demise.But Cordyceps is not something that humans have to worry about. No, we have our own fungal nasties and one of the worst is Cryptococcus neoformans... I mean it has the word "Crypt" right there in its name! But what does C. neoformans have to do with Cordyceps? Cryptococcus neoformansWell, for starters, it infects the brain. In fact it is the causal agent of the most common fungal disease of the central nervous system. Cryptococcal meningoencephalitis is a very dangerous illness, and is actually a major cause of death in AIDS patients.Our brain does have a good nervous system defense mechanism however; the Blood Brain Barrier. This series of tight junctions along its capillaries separates circulating blood from the nervous systems extracellular fluid. It acts basically as a gateway, restricting the diffusion of foreign particles and larger molecules into the cerebrospinal fluids, while allowing the small needed molecules (Oxygen, Hormones, etc.) through. This generally causes a pretty good barrier... but C. neoformans may have another thing in common with Cordyceps...A study published in PLOS One finds C. neoformans takes control of the Endothelial cells that constitute the Blood Brain Barrier. Not in the grand way that Cordyceps does, but in a much simpler way. It causes the cell to induce fusogenic activity, and fuses into the very barrier meant to keep it at bay.Cryptococcus neoformans-Derived Microvesicles Enhance the Pathogenesis of Fungal Brain InfectionYou see, while C. neoformans grows and infects, it produces microvesicles which contain components for the fungus's capsule. This capsule is generally considered to be a major determiner of how virulent a strain is because those lacking it are avirulent. These vesicles travel across the cell wall of the fungus carrying the building blocks to bio-synthesize the capsule.This study demonstrates the potential of these microvesicles in helping the pathogen traverse the blood brain barrier.To start, the researchers fused a fluorescence protein into one of the most common proteins in C. neoformans derived microvesicles in order to directly view presence and concentration of their formation.When human endothelial cells, such as those in the blood brain barrier, were exposed to the microvesicles ruffling of the plasma membrane was detected. As time progressed during incubation the fluorescence started increasing in the endothelial cells, suggesting that C. neoformans had invaded and was secreting more microvesicles within the cell.Looking at density gradients to determine the mechanism for these effects the scientist discovered an uptake of lipid raft activity in the presence of the C. neoformans microvesicles. This means that when these microvesicles are around, the cell itself increases the ability for the invader to adhere to and travel across the membrane barrier.In addition to this cell inducing, a secondary test to determine whether cell fusion took place was conducted. By dying multiple cell aliquots in distinct colors and presenting portions of them with microvesicles fusion would be detected by multi-fluorescent cells. And just as predicted, those not exposed did not fuse, while those presented with the invader did.Tests run in vivo with mice demonstrated that by increasing amounts of these microvesicles, along with a C. neoformans infection, there was a significant increase of brain infection by the fungus. Thus the team demonstrated that Cryptococcus neoformans derived microvesicles play a significant role in brain invasion.In this study, a glimpse of how devious pathogenic fungi can be is revealed. While the more dramatic members, such as Cordyceps, garner picture worthy attention. The subterfuge practiced by Cryptococcus is just as deadly a form of mind control. More akin to a vampire glamoring you to inviting it in, than to outright controlling your body like a puppet.A little too "In your face" for Cryptococcus.Awesome Researchers:Huang, S., Wu, C., Chang, Y., Kwon-Chung, K., Brown, R., & Jong, A. (2012). Cryptococcus neoformans-Derived Microvesicles Enhance the Pathogenesis of Fungal Brain Infection PLoS ONE, 7 (11) DOI: 10.1371/journal.pone.0048570 Photo Cred: By Dr. Graham Beards (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons... Read more »
Huang, S., Wu, C., Chang, Y., Kwon-Chung, K., Brown, R., & Jong, A. (2012) Cryptococcus neoformans-Derived Microvesicles Enhance the Pathogenesis of Fungal Brain Infection. PLoS ONE, 7(11). DOI: 10.1371/journal.pone.0048570
When man first began to settle out of the hunter-gatherer phase of our evolution we did so in fertile areas. We would perhaps stop where there was a constant source of water, and fair enough weather to allow us a safe and permanent homestead. But, as the world’s population increased those ideal spots became competitive and not everybody had access to things like constant supplies of water to manage crops with.Enter irrigation: the best agricultural idea since somebody first dropped a seed in a hole.In essence irrigation is simply transporting water from a source to a place where it is needed. Now, this has been going on a long time, evidence suggests the 6th Millennium BCE, and we have developed a whole host of styles. But in the end they all do the same thing; take water from here to there. Developing irrigation techniques allowed us to thrive in places without an immediate source of water, which opened the world up to us. It also led to a massive population boom (see everybody alive today).Long-Term Effects of Irrigation with Waste Water on Soil AM Fungi Diversity and Microbial Activities: The Implications for Agro-Ecosystem ResilienceAnd that is where we run into problems. You see as we grow more populous, we use more water, and leave more waste. So we are left with this transition: More access to water= more crops= more people= more waste= less clean water.But worry not! People are the ones who ingeniously developed irrigation in the first place, and now all we needed were ways to take the waters we contaminated and use them instead of freshwater. And we have. The use of treated wastewater is one of the most used alternatives to freshwater for irrigation in areas of limited natural resources.So, we have found ways to deal with dirty water: to take it and try to make it clean and reuse it. But the question is, at what cost? Now for most people here is where we would turn to crop yield, or potential health effects of eating foods grown with wastewater, but we both know that isn’t what I am concerned with.And a study recently published in PLOS One helps shed light on another impact of irrigating with wastewater: the effect on fungal diversity.This study from Southeast Spain measured the effects of irrigating an experimental orange grove with treated urban wastewater over the course of 43 years. The study included isolating and measuring Arbuscular Mycorrhizal Fungi (AMF) diversity in order to better understand techniques for management, sustainability, and productivity of the soils.They researchers sequenced 145 AMF samples that were grouped into 19 types, all from the Glomeraceae family. They sequenced multiple times to ensure full coverage of fungal diversity in both the wastewater irrigates as well as samples from a control plot of land that has been irrigated with freshwater.And there results demonstrated a significantly greater diversity of fungal species in the freshwater treated soils. With 15 different AMF types compared to only 10 from the Wastewater irrigated soils.The team speculated that the addition of nutrients to the soil could be a cause of lower AMF diversity, an observation backed up by evidence that shifts in community composition in nutrient-rich areas leads to a reduced AMF diversity.In this study they found a significant increase in enzymatic activities of alkaline phosphatase, urease, dehydrogenase, protease and β-glucosidase in the soils treated with wastewater. Previous long term studies measuring irrigation with municipal wastewater concur with this result on the activity of soil enzymes.The enzymes in the soil, and the introduction of readily available organics in the wastewater allows for a significant increase in microorganism populations. That actually has a beneficial effect on the total microbial biomass in treated soils, but the increased microorganisms don’t help with the Mycorrhizal diversity. It leads to the conclusion that while treatment with wastewater does have several benefits, it selects for the AMF’s that are most able to tolerate higher levels of enzyme activity in the soil. Using the results from this study could help us define methods to balance the soil microbiota to ensure the best yield per acre of healthy robust crops. See how I went back to crop yields there? And you thought I didn’t care about that.Awesome Researchers:del Mar Alguacil, M., Torrecillas, E., Torres, P., García-Orenes, F., & Roldán, A. (2012). Long-Term Effects of Irrigation with Waste Water on Soil AM Fungi Diversity and Microbial Activities: The Implications for Agro-Ecosystem Resilience PLoS ONE, 7 (10) DOI: 10.1371/journal.pone.0047680Photo Cred: Wikipedia contributor Paulkondratuk3194 ... Read more »
del Mar Alguacil, M., Torrecillas, E., Torres, P., García-Orenes, F., & Roldán, A. (2012) Long-Term Effects of Irrigation with Waste Water on Soil AM Fungi Diversity and Microbial Activities: The Implications for Agro-Ecosystem Resilience. PLoS ONE, 7(10). DOI: 10.1371/journal.pone.0047680
Just picture the soft blue light glimmering off some well developed stroma, strong mycelial growth subtly reaching out with its probing filaments. Some sexual reproduction is going down today.Now think of what it is like after that blue light so embodying of the twilight hour stays all the time, or never comes around at all. The light becomes harsh, showing off your conidiation, it is easy to see why stroma can't perform under such... revealing exposure. And while the velvet darkness can seem alluring, a constant darkness causes its own lack of enthusiasm, things may happen but the excitement oft isn't there, so it takes a while longer.Hypocrea jecorina sporting some sweet filamentous growth.Or at least that is what a new study in PLOS One says regarding the sexual development of Hypocrea jecorina under a variety of light exposure growth regimes demonstrates.Blue Light Acts as a Double-Edged Sword in Regulating Sexual Development of Hypocrea jecorina (Trichoderma reesei)Light is important to the sexual development of many fungi. Take Neurospora crassa, it has a complex of photoreceptive proteins (the white-collar complex) that directly initiate and manage sexual reproduction. However; the equivalent complexes found in H. jecorina, the blue-light photoreceptors (BLR1 & BLR2), regulate blue-light-induced mycelial growth and cellulase gene expression and the photoadaption protein ENV1 regulates the mycelial growth and tones down the detection of light change, which helps promote sexual development by inhibiting asexual conidiation. Basically that means BLR 1&2 and ENV1 play mainly regulatory roles and are not necessarily essential for sexual reproduction. To test whether visible light, and thus these photoreceptors, is required by the fungus for a sexually reproductive path, the researchers grew (on malt extract agar plates) H. jecorina under three separate light regimes; 24 hours of light a day, a 12 hour light/12 hours dark day, and a 24 hours of darkness day.The monitoring revealed that even after 30 days, the strains grown under a full 24 hour light day showed no stroma growth. This means all that total illumination inhibited the sexual development of H. jecorina. Those growing with the balanced 12hr Light/ 12hr Dark days? They knew what was going on ;-). They had a solid mycelial growth with well developed stromata being observed in just 7-9 days. However, when we jump back over to the fungi grown under total darkness, we see stromata form, but they do so more slowly. Also the stroma of the 12L/12D strains showed surface growth of perithecia (A flask shaped fruiting body that contains the ascospores), while the perithecia developing in the stroma of the 24D samples were embedded deeper toward the interior.These results demonstrated that different light variation greatly affected the sexual development of H. jecorina. While constant light completely inhibited Stroma formation, total darkness caused a slowdown of their growth as well. The second point explains why it has always been reported that light is required for stroma formation. Basically to induce proper sexual development Hypocrea jecorina there must be light, but it needs to be shut off now and then. Maybe, get a dimmer swith installed and turn on some Marvin Gaye.Awesome researchers:Chia-Ling Chen, Hsiao-Che Kuo, Shu-Yu Tung, Paul Wei-Che Hsu, Chih-Li Wang, Christian Seibel, Monika Schmoll, Ruey-Shyang Chen, & Ting-Fang Wang (2012). Blue Light Acts as a Double-Edged Sword in Regulating Sexual Development of Hypocrea jecorina (Trichoderma reesei) PLOS One DOI: 10.1371/journal.pone.0044969Photo Cred:US Department of Energy Office of Science via Wiki-Commons... Read more »
Chia-Ling Chen, Hsiao-Che Kuo, Shu-Yu Tung, Paul Wei-Che Hsu, Chih-Li Wang, Christian Seibel, Monika Schmoll, Ruey-Shyang Chen, & Ting-Fang Wang. (2012) Blue Light Acts as a Double-Edged Sword in Regulating Sexual Development of Hypocrea jecorina (Trichoderma reesei). PLOS One. DOI: 10.1371/journal.pone.0044969
Around the world we are seeing mass populations of frogs go into population decline. Heck, my very first actual blog post was about how a group of frogs in Southeast United States found a way to survive. But it isn’t alone.When looking at frog populations in the tropics one can find enough data to support the basic fact: Chytridiomycosis appears to be a cool weather disease. For one, lower temperature on a cold blooded frog leads to a potentially weaker immune system. And for another thing, Batrachochytrium dendrobatidis, the fungus responsible for a large portion of these infections, doesn’t grow as well in temperatures over 25C. That means frogs living in higher altitudes are more likely to suffer die-offs than those living in the lowlands. B. dendrobatidis does exist in the lowlands, mind you; it just doesn’t produce the dramatic results. But, as I briefly touched on in my first post, bacteria also help in warding off the pathogen. A study in PLOS One looks to analyze the bacterium growing on the skin of some persistent members of the frog genus Atelopus. Surviving Chytridiomycosis: Differential Anti-Batrachochytrium dendrobatidis Activity in Bacterial Isolates from Thre Lowland Species of AtelopusThere are over thirty species of frog in this genus, with all but four facing sharp decline. One of these remaining species, A. elegans, is standing strong even with B. dendrobatidis being well established in its population. What gives? This little guy should have met his mycelial maker!A. elegans: I should be dead!This study looks at the potential anti-fungal bacteria the species harbors, also comparing it to the microbiota of some closely related frogs that don’t appear to be infected with the pathogenic Chytrid. What they did was cultivate and isolate as many bacterial strains from roughly 80 specimens of three species of Atelopus: A. elegans, A. spurrelli, and A. limosus. This resulted in 148 cultivated strains that were tested for anti-B. dendrobatidis activity. The isolates of bacteria were streaked on plates which had been diffused with B. dendrobatidis to test for zones of inhibition as well as growth rates of the fungus throughout the dish. Along with each isolate a streak of E. coli was included as a control. E. coli is a bacterium which has been determined to have no inhibitive activity on B. dendrobatidis, and as such would act as a visual comparison of the active bacterial subjects.After analyzing the growth plates, roughly 40% of the strains isolated from Atelopus elegans showed anti-fungal action. In both A. spurrelli and A. limosus the percentage of active bacteria was much lower, 19% and 26% respectively. In addition to the quantities of bacterial strains, this same correlation was viewable in quality of inhibition; two of the three most active strains being only found in A. elegans with the third also being found on A. spurrelli.This seems to demonstrate that the only species of frog in the study which has tested positive for the pathogen employs a barrage of heavy hitting cutaneous bacteria to increase its resistance to chytridiomycosis.While it acknowledges that laboratory conditions would differ from host the environment of the host frog’s skin; the research team believes the bacteria isolated in this study, specifically the two members of the Pseudomonas genus (P. tolaassii and P. aeruginosa) that showed strongest inhibitor action, could help combat the fungal pathogen in neotropical habitats as probiotic treatments. Awesome Reasearchers: Sandra V. Flechas, Carolina Sarmiento, Martha E. Cárdenas, Edgar M. Medina, Silvia Restrepo, & Adolfo Amézquita (2012). Surviving Chytridiomycosis: Differential Anti-Batrachochytrium dendrobatidis Activity in Bacterial Isolates from Three Lowland Species of Atelopus PLOS One DOI: 10.1371/journal.pone.0044832Photo Cred: Wiki Commons Contributor Phillip Weigell... Read more »
Sandra V. Flechas, Carolina Sarmiento, Martha E. Cárdenas, Edgar M. Medina, Silvia Restrepo, & Adolfo Amézquita. (2012) Surviving Chytridiomycosis: Differential Anti-Batrachochytrium dendrobatidis Activity in Bacterial Isolates from Three Lowland Species of Atelopus. PLOS One. DOI: 10.1371/journal.pone.0044832
The genus Pestalotiopsis is home to some well known plant pathogens. While generally not causing severe disease, they are always willing and ready to take advantage of weakened or injured foliage. One species, Pestalotiopsis microspora, even has a well documented ability of digesting polyurethane.However; catagorizing the species within this genus can be quite daunting, it has a confusing taxonomic history. For instance the spores of Pestalotiopsis looks remarkably like Seiridium abietinum, except that S. abietinum lacks a multi-apendaged end.Top Pestlotiopsis, Bottom SeiridiumNow a new study published in Fungal Diversity, hoping to clear up some of the mess, has conducted a multi-loci genetic analysis on 40 isolates comprised of 28 strains from Pestalotiopsis. A multi-locus backbone tree for Pestalotiopsis, with a polyphasic characterization of 14 new speciesAfter isolating the samples the team studied both morphology and genetic sequence data, focusing on 10 gene regions generally utilized to help resolve cryptic Pestalotiopsis species. Unfortunately most of the regions served limited purpose due to an inability to outline species boundaries, as well as a low success in PCR amplification. However; β-tubulin, tef1, and ITS all demonstrated themselves as strong marker regions. And while they each proved to be a good source to identify differences among species, working with all three gave exceptional mapping capabilities.And what happened when all this data was analysed?... 14 new species:Pestalotiopsis asiatica, P. chinensis, P. chrysea, P. clavata, P. diversiseta, P. ellipsospora, P. inflexa, P. intermedia, P. linearis, P. rosea, P. saprophyta, P. umberspora, P. unicolor and P. verruculosa.But don't let adding new species make you think they are adding to the confusion, in fact this research gives a solid, in their terminology, backbone tree for the 22 known pestalotiopsis species. Using their research will prove invaluable to further studies in this genus.Awesome researchers:Sajeewa S. N. Maharachchikumbura, Liang-Dong Guo, Lei Cai, Ekachai Chukeatirote, Wen Ping Wu, Xiang Sun, Pedro W. Crous, D. Jayarama Bhat, Eric H. C. McKenzie, & Ali H. Bahkali (2012). A multi-locus backbone tree for Pestalotiopsis, with a polyphasic characterization of 14 new species Fungal Diversity DOI: 10.1007/s13225-012-0198-1Video Cred: The New Haven RegisterPhoto Cred: ... Read more »
Sajeewa S. N. Maharachchikumbura, Liang-Dong Guo, Lei Cai, Ekachai Chukeatirote, Wen Ping Wu, Xiang Sun, Pedro W. Crous, D. Jayarama Bhat, Eric H. C. McKenzie, & Ali H. Bahkali. (2012) A multi-locus backbone tree for Pestalotiopsis, with a polyphasic characterization of 14 new species . Fungal Diversity. DOI: 10.1007/s13225-012-0198-1
Ah, the time old conflict of a surgeon and a medical doctor. Do we treat an ailment with drugs or scalpels? If we choose drugs, are we just culling the weak and leaving the strong pathogens? If we choose to operate, are we putting patients through excessive procedures and how do we know we have gotten everything?One of the recent battles in this war was fought over moderate cases of Fusarium keratitis by researchers at the Chang Gung University College of Medicine (CCUCM). Early Keratectomy in the Treatment of Moderate Fusarium Keratitis Keratitis is an inflammation of the cornea. While it has a number of causes ranging from over exposure to light (such as during snow blindness) to herpes virus infection, Fusarium keratitis is dealing fungal infection. Actually, as the name implies it is dealing with fungi from the Fusarium genus. And keratitis caused by these fungi can present quite the treatment ordeal. For starters they are filamentous: which means they grow a nice cottony mycelial blanket in/ on the eye. Unfortunately by the time this is visible you have already moved past the initial stages of the infection. It takes up to a few weeks after the germ tube starts for full infiltration and inflammation to become apparent. Up to that point you just sit there with individual feathery hyphae, poking and prodding their way across your cornea.Progress of Fusarium keratitisWith minor cases the simplest solution is just medical treatment, but as it becomes more advanced surgical intervention is often needed. But what about those moderate cases in the middle? The ones where it may go away with treatment, but then again maybe it won’t. That range of infection is the focus of the CCUCM teams study.The researchers investigated 38 cases of moderate Fusarium keratitis between January 2004 and December 2010. Of those patients 13 got keratectomies within a week of entering the hospital and twenty were only treated medically. Out of the patients, five of them didn’t have follow up records and were thus discarded from the research conclusions. There were no major differences between these two groups in regards to age, sex, or severity of eye infection; however it was noted that the medicated group did average a significantly worse baseline vision than the surgery group.While reviewing all records the group contrasted costs, hospitalization days, disease duration, and perforation progress between the contrasting treatments. Eye photographs were documented weekly and any progress or negative response led to a reculture for Fusarium after a 24 hour break of topical antibiotics.The results seem to be a straight up win for the surgeons. The group receiving keratectomies had a much shorter duration of the disease, with an average of 29 days vs. 54 days; and of those days the surgery group was only in the hospital 11 days, compared to the medical groups average 31 day stay. Of course the longer stay for those receiving medication also caused a severe jump in cost, having a range centering around 20,000 New Taiwan Dollars higher. And addressing the largest physical end comparison, the degree of corneal perforation following the procedures: in this study group 20% of those treated with medicine only developed perforations, while absolutely none of the patients that went through surgery did. The Scalpel jockeys seem to have sliced out a victory here.That being said the research team did acknowledge that this was just a retrospective study and with treatments based on the preferences of the physicians, which allowed for potential biases. Now for the real purpose of this post:Awesome researchers:Hsin-Chiung Lin, Ja-Liang Lin, Dan-Tzu Lin-Tan, Hui-Kang Ma, & Hung-Chi Chen (2012). Early Keratectomy in the Treatment of Moderate Fusarium Keratitis PLOS One DOI: 10.1371/journal.pone.0042126... Read more »
Hsin-Chiung Lin, Ja-Liang Lin, Dan-Tzu Lin-Tan, Hui-Kang Ma, & Hung-Chi Chen. (2012) Early Keratectomy in the Treatment of Moderate Fusarium Keratitis. PLOS One. DOI: 10.1371/journal.pone.0042126
There has been a well documented decline of honey bee colonies across the globe. One of the prime causative agents has been determined to be the fungal genus Nosema. The infections by these fungi are generally passed through a fecal oral pathway (You read that right, fecal-oral). And in order to facilitate their spread the members of this genus often induce increased defecation. I want to point out that this means they give bees diarrhea, I never even knew bees could get diarrhea! The concept never even crossed my mind... Anyways, one member of the Nosema genus, N. ceranae, in fact does not have increased defecation as a symptom; which begs the question, how does it spread? A study by Michael L. Smith of Wageningen University seeks to answer exactly that question.Bee SquirtsHis basic premise is that since Nosema ceranae does not induce pooping, logically it must be spread via another pathway. And with that in mind he focuses this study on the potential spreading of spores through oral transfers of food. The Honey Bee Parasite Nosema ceranae: Transmissible via Food Exchange?To test the hypothesis he set up a series of hoarding cages with varying degrees of separation between infected older bees and non-infected young bees. This way the older bees would feed the younger if able and potentially spread spores of N. ceranae to them. While the test cannot rule out any fecal transmission, (the spores are still present there, the fungus just doesn't give the bees the runs) it does cut down on exposure via that pathway. The three degrees of cage separation were as follows: A single screen between the cages would allow for the transfer of food but not allow intermingling, a dual screen would keep the older bees from even getting a chance to feed the younger ones, and a control of isolated young bees would, well, act as a control for natural exposure.First, to ensure infection, the bees destined to be used as "Older bees" were taken from their hives and marked. They were then coated with a sucrose solution laced with N. ceranae spores. As they cleaned themselves they ingested the spores leading to infection. These bees were then allowed to incubate their new parasite for 12 days before being collected and used in the first of three trials. A second set of trials was conducted with the older bees not being artificially infected but picked to represent a natural spread in colony.The "Younger bees" for the test were taken directly from combs using an aspirator quickly after emergence and isolated until test runs.For the testing the cages were placed next to each other in the aforementioned set ups for 4 days. In all sets the older bees were fed a sucrose solution and in the case where young would not be reachable they too were fed the same type solution. However; in the young bees directly adjacent to the old bee cage, no food was provided on days 2-4. This forced them to receive food via feeding from the older bees. Mortality of the young bees during this time was no different than the rest of treatment times.After the exposure was complete the bees were then allowed to incubate for 10 days before being dissected to detect infection. For the dissection each bee had its midgut extracted and opened under a microscope. Then spore presence was observed by looking at 25 field views for each sample. Due to the high colonization of infected bees only bees counted with >100's of spores were counted as infected. And the infection rates showed very strong correlation with the single screen exposure. In fact, while there was not much notable difference between the dual screen and the control group, the single screen bees showed a 13 times higher rate of infected young bees.The researcher does take special time to note that while precautions to prevent defecation spread were taken, and that no feces were observed on the separation screen, there is still potential that the fecal-oral pathway could still potentially be a factor in spread. But despite that the study gives the first experimental support to the hypothesis that N. ceranae is spread through oral-oral exchange.Awesome researcher:Michael L. Smith (2012). The Honey Bee Parasite Nosema ceranae: Transmissible via Food Exchange? PLoS One DOI: 10.1371/journal.pone.0043319Photo/Gif cred:Wiki Commons Contributer Athen_Ananda... Read more »
Michael L. Smith. (2012) The Honey Bee Parasite Nosema ceranae: Transmissible via Food Exchange?. PLoS One. DOI: 10.1371/journal.pone.0043319
So I have talked several times about the wonders of Mycorrhizal relationships, but did you know that not all fungi growing on roots fit into this group? It’s true, and these colonizers, known as endophytes, run the full gambit of beneficial to pathogenic for their host. What is a plant to do? Well, a new study out in PLOS One suggests the best course of action is to hope for a true mycorrhizal symbiosis to help keep their neighbors in check.Mycorriza Reduces Adverse Effects of Dark Septate Endophytes (DSE) on Growth of ConifersThe team of Vanessa Reininger and Thomas Sieber looked at the effects of colonization by Phialocephala fortinii and Acephala applanata, a couple of ascomycetes that like to room together under the acronym PAC, with and without the presence of a common mycorrhizal fungi named Laccaria bicolor.Laccaria bicolorThe PAC combination is routinely isolated from root tips throughout the Northern Hemisphere. It is in fact the most common complex and thus the main component of the Dark Septate Endophytes, a group of fungi identifiably by their… you guessed it, darkly pigmented septates. While these colonizers can sometimes be beneficial to the host plant they can sometimes be pathogenic and harmful instead.There have been several studies on endophytes interacting with plants, and several on mycorrhizal relationships, but this study seeks to complete the circle and find out the interplay these two groups have with each other. Since both are clear hosts of L. bicolor and PAC in nature, the scientists chose to study these interactions on the Douglas fir and Norway spruce.To do this the research team incubated L. bicolor into growth tubes for five and a half weeks, and then planted sterile seeds into said tubes. After allowing the plants to grow for another three and a half weeks they inoculated their roots with one of four PAC strains. Each combination, as well as a completely fungus-free control, was then grown at both 19°c and 25°c. The trees were grown for five months after inoculation under these conditions and root segments were excised for analyses. Each sample was measured for plant biomass, root vs. shoot growth ration, and fungal biomass.One major factor across all data points was the growth temperature. On all plants this significantly altered both plant growth and colonization rates of both mycorrhiza and endophytes. But this study was meant to focus on the relationship of mycorrhiza and endophyte so I will too.PAC strains were able to more densely colonize on Douglas fir then they were on Norway spruce as well as at the lower 19°c temperature. Mycorrhized plants significantly decreased the growth of PAC in both plants. It is noted by the researchers however that we have to take into account that L. bicolor was allowed to colonize before the inoculation of PAC.The biomass of trees was also increased in the presence of mycorrhyzation compared to PAC. The fungal-free controls performed or outperformed both of these though.Lastly the plants colonized solely by PAC invested more into root growth than both the controls and those with a mycorrhizal relationship. This means mycorrhizal symbiosis allowed the plant to focus on shoot production instead of fighting for nutrients with its fungus.The researchers demonstrated that mycorrhization by Laccaria bicolorhandily kept the team of Phialocephala fortinii and Acephala applanata from getting out of control; letting both the Douglas fir and Norway spruce get on with its day to day routine. Since all of these fungi live in close relation to each other in the wild the team speculated that this same mechanism is in play.Awesome researchers: Vanessa Reininger, & Thomas N. Sieber (2012). Mycorrhiza Reduces Adverse Effects of Dark Septate Endophytes (DSE) on Growth of Conifers PLoS One DOI: 10.1371/journal.pone.0042865Photo cred:US Department of Energy via Wikimedia... Read more »
Vanessa Reininger, & Thomas N. Sieber. (2012) Mycorrhiza Reduces Adverse Effects of Dark Septate Endophytes (DSE) on Growth of Conifers. PLoS One. DOI: 10.1371/journal.pone.0042865
Killing a fungus doesn't mean you are free from its infectious grasp. You see many pathogenic fungi (and bacteria) grow in what is referred to as a biofilm, and killing the fungus doesn't make the biofilm magically disappear. If you think for a second that is obvious; killing a person wouldn't make the body go away, if it did the boys from Pulp Fiction would never have called in The Wolf.Anyway, the biofilm is the complex of organisms living together in a self created extracellular matrix. That matrix does a number of things; it supplies a structure for the colony, holds some of the nutrients from the surrounding environment, and it offers protection from things like host responses and microbial forces. Obviously killing the pathogen itself is the number one goal, but without actual removal of the infector, the host is still open to inflammation and secondary infection. Biofilms of pathogens are involved in well over half of infections contracted by once in a hospital. The problem is that conventional cleaning and disinfecting procedures biofilms often remain. It is for this reason that a new study has attempted to see the potential effectiveness of Plasma Torches on biofilms... Ok, technically Low-Temperature Atmospheric Pressure Plasma, but come on this is a torch: Biofilm blasting Plasma Torch, driven with 5 slm Ar and 0.05 slm O2, impinging a polymer surface.Plasma treatment has been shown to be effective in killing pathogens and has been extensively studied in sterilizing and cleaning biomedical materials. But what about its potential for combining these aspects into killing and removal of biofilms in one awesomely torch-tastic moment?A new study by researchers out of Germany seeks to answer this question. The team basically grew Candida albicans biofilms on a flat surface and blasted the hell out of it with an Argon plasma jet, and then also with a combination jet of Argon and Oxygen. They then used microscopic imaging to detect whether or not there was any biofilm remaining.Atmospheric Pressure Plasma: A High-Performance Tool for the Efficient Removal of BiofilmsC. albicans is a good model for this study because it is one of the most prevalent biofilm creating pathogens. It is known to colonize pretty much everything from dental materials to prostheses and is responsible for some majorly life threatening infections. And it is also a fungus, so I get to talk about this study. The team grew C. albicans on a Polystyrene wafer that was pre-treated to enable a uniform colony growth on its surface. They did this by growing the fungus in a broth and then transferring a sample onto the wafer. The samples were incubated for 7 days, with a medium change every twenty-four hours, and then wafers were washed with a saline solution to remove any left overs.And now for the plasma treatment. Since previous studies suggested that a small distance allowed for the greatest plasma etching, the scientists held a constant distance of 7mm between the nozzle and sample. They then proceeded to subject the C. albicans, along with its biofilm matrix, to 60, 120, 180 and 300s of Argon plasma jet. They used a control that was exposed to the gas without full on plasma ignition. They repeated this with the aforementioned mix of Argon with a hint of Oxygen.At 300s the Argon plasma did its initial job, killing C. albicans, but it didn't quite have the up-and-at-em to completely remove the biofilm entirely. However, as you can see in the below picture, adding some good 'ol Oxygen to the Plasma made for a clean wafer. The major caveat is that a plasma jet treatment is localized; I mean it can only hit the pathogen directly in front of it.So, while more testing is always a good thing, this study demonstrates the potential use of Non-thermal plasma in efficiently removing C. albicans biofilms from surfaces. This could open up new possible sterilization and bio-decontamination techniques. Plus maybe it is the first step down the road to get a Plasma globe into every laboratory like on old sci-fi shows.Awesome Researchers:Katja Fricke, Ina Koban, Helena Tresp, Lukasz Jablonowski, Karston Schroder, Axel Kramer, Klaus-Dieter Weltman, Thomas von Woedtke, & Thomas Kocher (2012). Atmospheric Pressure Plasma: A High-Performance Tool for the Efficient Removal of Biofilms PLoS One DOI: 10.1371/journal.pone.0042539Additional Photo Cred(Plasma ball):Blaise Frazier aka PiccoloNamek via WikiCommons... Read more »
Katja Fricke, Ina Koban, Helena Tresp, Lukasz Jablonowski, Karston Schroder, Axel Kramer, Klaus-Dieter Weltman, Thomas von Woedtke, & Thomas Kocher. (2012) Atmospheric Pressure Plasma: A High-Performance Tool for the Efficient Removal of Biofilms. PLoS One. DOI: 10.1371/journal.pone.0042539
I think it is safe to say everyone loves orchids. And if by some chance you don't then you are dead to me, go read something else.Now for all of you wonderful people that matter, which is of course everyone because nobody could belong to that other group, orchids are some an extremely diverse family of flowers. They grow all around the world and make up to about 10 percent of all seed plants. There are over 20,000 species which includes not only your typically prized Orchid flower but also things like vanilla. And guess what. Without fungi they wouldn't exist.Dactylorhiza incarnataYou see, orchids are one of those many, many plants that rely on a mycorrhizal relationship with fungi to get nutrients. In fact some studies suggest that the distribution and specificity fungi are in part responsible for the rarity of some orchids. Recent research on the mycorrhizal relationships of Caladenia demonstrate that this in combination with other environmental goings on had a great impact on plant rarity.A study recently out in PLoS One takes a look at this special relationship in five species from the Dactylorhiza genus. Variation in Mycorrhizal Associations with Tulasnelloid Fungi among Populations of Five Dactylorhiza SpeciesThe teams findings set to determine what species of fungi, as well as whether that specificity affected the rarity of species at least in this genus. And they found that the sampled Dactylorhiza species were not that stingy with whom they hooked up with.On the five flower species they found 10 different isolatable fungal species with an average of 3 per plant (some had 2 others had 5 or six). The isolated fungi all came from the genus Tulasnella, which is a common symbiont of terrestrial orchids including several different genera. Most of the isolated Tulasnella species were found on more than one orchid of this study, and some of them were widespread amongst the specimens. What this shows is that in contrast to the studies suggesting specificity amongst mycorrhizal symbionts, at least in Dactylorhiza a wide host of fungi could be utilized to get the job done. And while this study tackled whether or not mycorrhizal specificity was a major factor in Dactylorhiza, future tests focusing on other environmental conditions could help see if it triggered a constricted association. According to the researchers, more studies could also help determine what the purpose of multiple fungal infections is. Do they work in different ways to help acquire nutrients for the plant, or are they maybe competitors within the root system?Awesome researchers:Hans Jacquemyn, Agnieszka Deja, Koen De hert, Bruno Cachapa Bailarote, & Bart Lievens (2012). Variation in Mycorrhizal Associations with Tulasnelloid Fungi among Populations of Five Dactylorhiza Species PLoS One DOI: 10.1371/journal.pone.0042212Photo Cred:Roepers at nl.wikipedia... Read more »
Hans Jacquemyn, Agnieszka Deja, Koen De hert, Bruno Cachapa Bailarote, & Bart Lievens. (2012) Variation in Mycorrhizal Associations with Tulasnelloid Fungi among Populations of Five Dactylorhiza Species. PLoS One. DOI: 10.1371/journal.pone.0042212
Your skin is a vast and complex habitat. There are all kinds of bacteria and fungi competing for every inch of real estate. But like all homesteads, resources are limited. Bacteria lower surface area pH rendering it inhospitable for others, and secrete chemical compounds to kill invaders. Fungi have found ways to more efficiently mine the "land" for minerals such as iron, as well as producing antibiotics that are specifically active against skin bacteria.One of the families of fungi capable of infecting skin (Dermatophytes) is Arthrodermataceae, A family that includes the genera Microsporum and Trichophyton. These two fungi groups colonize keratinized areas and together are the most common cause of superficial fungal skin infections.MicrosporumTrichophyton A study in the July 30, 2012 edition of PLoS One takes a look at some of the closely related genes, gene clusters, that allow the species from Microsporum and Trichophyton to take such good advantage of the terrain that is your skin.Two Different Secondary Metabolism Gene Clusters Occupied the Same Ancestral Locus in Fungal Dermatophytes of the ArthrodermataceaeIn essence gene clusters are several genes that are physically linked or clustered together that share a common effect, such as production of antibiotics, or metabolically important compounds. Gene clusters can allow for quicker adaptation to new sources of sustenance as well as large scale genome remodeling. Due to the closely knit nature of gene clusters they also open the possibility of acquiring new functions by gain and loss of entire gene pathways through horizontal transfer.Arthrodermataceae have a lot of gene clusters that many think are involved in host specificity and pathogenicity, especially when compared to other dermatophytes. Focusing on variable loci nestled inside a stable portion of the genome of Microsporum canis, Microsporum gypseum, and Trichophyton spp.; the researchers discovered three distinct conformation forms.This variable locus(VL) has a difference of both length and functions across the three species. M. canis VL (VLA) consists of 539 base pairs that lack any protein sequencing sequences, M. gypseum (VLB) only has 35.89 bp but codes 12 different proteins, and Trichophyton spp.'s VL (VLC) is 26.78 bp long coding for 10 proteins.When looking at the evolutionary past of the gene region it becomes apparent that the studied clusters have a very different history than the areas surrounding them. Those flanking regions have a largely vertical inheritance while the VL genes have been shaped by several different processes, including gene duplications and gene transfers.The VL's of M. gypseum and Trichophyton spp. contain genes to produce compounds that appear to target glycine, which is the largest amino acid in human skin. This means the VL may be involved in skin colonization and thus infection. The effects of this area along with the evidence of gene duplications and losses led the team conclude that the common ancestor of these dermatophytes shared either a polymorphic version of VLB and VLC or both of them separately.If the first scenario is correct, the common ancestor originally contained a version of the VL that alternated between the VLB and VLC form. During the evolution following that point the entire area was deleted from M. canis and the alleles were separated into the stable forms in M. gypseum and Trichophyton spp.If the secondary version is true than at different times the main lineages came into their current genomic distributions by separate deletions in and of the VL.It would take additional genome sequencing of closely related species in Arthrodermataceae, to determine the more likely of these two scenarios.In the end, the mere existence of variable loci, like those in this study, could help explain how closely related species could show a dramatic difference in ability to establish an epidermal foothold.Awesome Researchers:Han Zhang, Antonis Rokas, & Jason C. Slot (2012). Two Different Secondary Metabolism Gene Clusters Occupied the Same Ancestral Locus in Fungal Dermatophytes of the Arthrodermataceae PLoS One DOI: 10.1371/journal.pone.0041903Photo creds: Robert J. Galindo & the CDC via Wikimedia... Read more »
Han Zhang, Antonis Rokas, & Jason C. Slot. (2012) Two Different Secondary Metabolism Gene Clusters Occupied the Same Ancestral Locus in Fungal Dermatophytes of the Arthrodermataceae. PLoS One. DOI: 10.1371/journal.pone.0041903
Humans are not alone when it comes to farming. We are not even alone when it comes to growing fungi. There is a long history of fungal agriculture in social insects. Ant and termites often even go so far as to have what could basically be considered proper gardens of fungal blooms; getting them into the right growth medium, tending to their needs, even defending them from invaders. It is all quite industrial, but that is the kind of thing we come to expect from ants.Now a Japanese study is demonstrating that at least one less industrialized, even non-social, beetle has tapped into the joys of harvesting fungi.Fungal Farming in a Non-Social BeetleThis study focuses on a species of lizard beetle, Doubledaya bucculenta, that lives in Japan and lays eggs in dead bamboo. Collecting specimens of D. bucculenta at Kawaminami, Miyazaki Prefecture, Japan The team found that there was a white coating in internode cavities that were used to contain larvae, as well as on the larvae themselves.D. bucculenta, its host bamboo, and W. anomalusAnalyzation of this growth consistently showed the saccharomycete yeast Wickerhamommyces anomalus present in the shoots used by D. bucculenta. Looking at bamboo not used for the incubation of young this same fungus was absent. When you find a fungus repeatedly, and only, growing in the presence of developing larvae, you might want to wonder if something is up.By gathering and dissecting both adult males and females of D. bucculenta an interesting structure was catalogued. The females all displayed a yellowish exoskeletal pocket on the eight abdominal segment, right next to the ovipositor, and guess what they found there. Correct! They found small yeast particles that when isolated and sequenced turned up with the identical DNA of W. anomalus that had already been collected.So, is this yeast a parasite, perhaps feeding off the larvae of the beetle or the insides of the bamboo? Or, could it be that the beetle was engaging in some low level farming, putting a crop into its young's room for later. W. anomalus is known to be saprophytic so it could potentially be using the beetle as a transport to get on the inside of freshly dead bamboo, but that would hardly be cause for the storage pocket on the female beetle. If however, the beetle were harvesting the fungus and seeding the bamboo chamber with it when she deposited her egg, how would that affect the larva?To test this, the researchers grew some beetle larvae under a variety of scenarios. When inoculated with W. anomalus the larvae grew normally into adulthood, however when grown on sterile media or in autoclaved bamboo they stopped growing at the second instar. Furthermore after this if W. anomalus was added the larvae returned to its normal growth and development.So, it appears that D. bucculenta does indeed harvest and transplant W. anomalus into the incubation chamber of its young. This interesting mutualistic relationship has led the beetle to becoming obligately dependent on the very fungus it developed a structure to harvest.In the end finding this fungal farming tactic in a non-social insect could help shed light on how some of the higher levels of mutualistic cultivation developed. And in the end, the researchers think this could shed light even on how agriculture developed as a whole.Awesome researchers:Wataru Toki, Masahiko Tanashi, Katsumi Togashi, & Takema Fukatsu (2012). Fungal Farming in a Non-Social Beetle PLoS One DOI: 10.1371/journal.pone.0041893... Read more »
Cryptococcus neoformans is a well know fungal pathogen that can cause severe infections of the pulmonary and nervous systems. Infections of people with well functioning immune systems are rare but in those with compromised systems such as those with HIV, this opportunistic yeast is responsible for encephalitis and fungal meningitis.Cryptococcus neoformansOf course it needs its daily recommended allowance of vitamins and minerals. A Study conducted by scientists from Konkuk University and Chung-Ang University in Republic of Korea seeks to specifically check out the effect iron regulation has on C. neoformans day to day life.Influence of Iron Regulation on the Metabolome of Cryptoccocus neoformans.You see, iron is important for a whole host of processes. It is used in the tricarboxylic acid cycle, amino acid creation, respiration, as well as making lipids and sterols. The thing is, too much iron is bad, if level get to high it leads to the creation of oxygen radicals. Oxegyn radicals are bad mamma jammas; they cause things like DNA breakage and protein denaturing. Yup, iron is important, but you need to keep it in check or all kinds of things are going wrong.It has been established that Cir1 is an important regulatory protein for iron transport and homeostasis. The same study showed Cir1 to be important to melanin formation and synthesis of spore capsules, things very important to the virulence of C. neoformans. With all of the metabolic pathways influenced by deletion of this protein and its importance on the regulation of iron, the team of researchers chose see the metabolic effects the deletion of Cir1 would have in order to get a large picture on its function in C. neoformans.To study this they utilized Gas chromatography mass spectrometry and chemometric multivariate statistics to analyze the metabolomic profiles of a wild type and a Cir1 mutant strain lacking the regulatory protein. They attempted to find the pathway(s) most affect by a lack of Cir1 and how it affects the metabolome of C. neoformans. The strains were grown on a range of media, with varying amounts of available iron.Because of the similarity and complexity between the Cir1 mutant and the wild type, the researchers used principle component analysis on the 972 peaks shown in the data sets, comparing the variation in 18 discriminative metabolites that showed significant difference.When compared between the high and low iron mediums the chosen metabolites of the Cir1 strain showed little changes despite a significantly increased level of iron present in the Cir1 mutant cells. That led the team to conclude that iron availability was only responsible for minor differences in C. neoformans. However, when looking at the regulation of genes in the wild type things were a little different. 483 genes were down-regulated and 250 were up-regulated in low iron vs high iron growth medium. Most of those differently expressed genes had to do with iron transport and homeostasis, as well as DNA repair and metabolism.The study also showed dramatic influence of Cir1 on metabolism and production of those molecules involved.One of the most interesting differences in the mutant was a large increase in glucose production. An increase in glucose implies that deleting the Cir1 had affects on the major carbon assimilation processes because glucose is metabolized in glycolysis and important in the TCA cycle and respiration. The TCA cycle and respiration are also influenced by iron so there is potentially connection there.Combining those observations allows for the suggestion that an increase in intracellular iron and glucose are evidence of lowered iron requiring processes like glycolysis and respiration.Another increase was shown in ergostol and its derivatives. Ergostol is the major constituent in fungal cell walls and is the target of some antifungal drugs. This increase of production is evidence of why Cir1 mutants have been demonstrated to be more resistant to anti-fungal treatment. A change in the production of ergostol and its derivative molecule means a remodeling of membrane biosynthesis.The basis of many secondary messengers, inositol was also increased significantly in the Cir1 mutant. This suggested up-regulation of inositol metabolism in Cir1 deletion was further seen by an increase in virulence important genes that are derived from it.All of this together revealed that deletion of one of the major iron regulating genes in C. neoformans also impacts several of the iron required pathways. Taking out the Cir1 protein led to a change in respiration, glycolysis, as well as synthesis of membranes and messenger pathways.When studying the effects of a protein, gene, or any other molecule on a system, this study demonstrates that one must remember, life is complex as all get out. While not everything is truly intertwined, the impact one thing has another is often multifaceted and unpredictable.Awesome Researchers:Jung Nam Choi, Jeongmi Kim, Won Hee Jung, & Choong Hwan Lee (2012). Influence of Iron Regulation on the Metabolome of Cryptococcus neoformans PLoS One DOI: 10.1371/journal.pone.0041654Photo cred:Centers for Disease Control and Prevention's Public Health Image Library identification number #3771... Read more »
Jung Nam Choi, Jeongmi Kim, Won Hee Jung, & Choong Hwan Lee. (2012) Influence of Iron Regulation on the Metabolome of Cryptococcus neoformans. PLoS One. DOI: 10.1371/journal.pone.0041654
Chances are it is inside you right now, waiting. The moment you let your guard down Candida albicans will be there to spring into action. This versatile fungus can grow both as a yeast and pseudohyphally and it knows how healthy you are.White and Opaque versions of Candida albicansCandida albicans normally colonizes our bodies without symptoms; but when your immune system becomes compromised it takes quick advantage and moves on the offensive, generally causing minor infections but capable of much deadlier ones.But how does it know what is up? A study published in mBio looks to answer that very question.Variation in Candida albicans EFG1 Expression Enables Host-Dependent Changes in Colonizing Fungal PopulationsGrowing C. albicans in mice with healthy and immunodeficient mice, the team hoped to compare growth patterns and phenotypic variants, concentrating largely on transcription factor Efg1p activity.Efg1p is an important physiological regulator for C. albicans and earlier studies have demonstrated that it influences the harmful potential that the fungal cell has.In this study the scientists show that it also regulates colonization dynamics, having different expression and activity in individual cells throughout. Their study also demonstrates how the host environment changes the C. albicans population composition, thus changing the colonizer's physiology. To test the growth rates of C. albicans with different levels of Efg1p the researchers basically fed healthy and immunosensitive mice with strains of C. albicans that had both low and high expression of the transcription factor. Then they counted fecal pellets for colonization patterns.As it turns out those mice with strong immune systems showed a higher growth of cells with a high expression of Efg1p and those with a compromised immune system showed larger growth of those with low activity. The scientists propose that in a general, there is a heterogeneous population growth. With that expression as the C. albicans comes into contact with an immune system it can adjust its physiology to be most productive despite the varying levels of immune system health.What this could mean is that as the host's immune system becomes less affective the larger population of low Efg1p active cells will show a spike in growth, thus setting up the colony for engaging in pathogenic actions.So, in the end, measuring the ratio of high and low active Efg1p cells in a system could help to us determine host immune status as well as develop new methods for detecting and fighting Candida caused infections before they become severe or deadly. This study gives us a small insight to how we can keep an eye on one fungus that is just waiting for us to falter.Citation:Jessica V. Pierce, & Carol A. Kumamoto (2012). Variation in Candida albicans EFG1 Expression Enables Host-Dependent Changes in Colonizing Fungal Populations mBio DOI: 10.1128/mBio.00117-12Photo: Rebecca E. Zordan, Mathew G. Miller, David J. Galgoczy, Brian B. Tuch, Alexander D. Johnson via http://en.wikipedia.org/wiki/File:Whiteopaquecandida.jpg... Read more »
Jessica V. Pierce, & Carol A. Kumamoto. (2012) Variation in Candida albicans EFG1 Expression Enables Host-Dependent Changes in Colonizing Fungal Populations . mBio. DOI: 10.1128/mBio.00117-12
One thing that we can all agree on about fossil fuels is that they are non-renewable. Because of that simple fact it is obvious we have to find new and efficient ways to continue meeting our fuel needs. One of the methods growing (pun intended) in popularity is the production of bioethanol via the fermentation of plant carbohydrates.S. cerevisiaeThe yeast, Saccharomyces cerevisiae is very good at fermenting the ethanol from hexose sugars. That and its high tolerance to the ethanol it produces have led it to become one of the most utilized characters in Industrial scale bioethanol production. But it could be better.You see, there is another sugar that exists in abundance in cellulosic biomasses. That sugar, xylose, is in fact so abundant that it is second only to glucose quantity. But S. cerevisiae just can't handle xylose. This is where we turn to another yeast, Pichia stipitis. P. Stipitis excels and turning xylose into ethanol, however it has its own short comings. This apparent upstart fails miserably when it comes to ethanol tolerance, a detrimental flaw that renders it nonviable as a large scale producer. If only there was some way to bring these two together...Enter the duo of Wei Zhang and Anli Geng from the school of life and chemical technology of Ngee Ann Polytechnic, in Singapore. These two have contrived of a way to instill the xylose eating skills of P. stipitis into the hearty bioethanol standard bearer S. cerevisiae through genomic shuffling.Improved ethanol production by a xylose-fermenting recombinant yeast strain constructed through a modified genome shuffling methodThe team looked at traditional way used in teasing S. cerevisiae into fermenting xylose, generally metabolic engineering, and thought there had to be a better way. Metabolic engineering requires the expression of multiple genes through mutagenesis and then post-evolutionary engineering. The process has to be done throughout the complex genomic pathways, and as such takes a lot of work and a lot of time. Genomic shuffling on the other hand enables the team to make changes throughout the entire genome at the same time.Now, before you ask, "Well, then why don't we always use whole genome engineering?" know that it has its downsides. Genomic shuffling depends very heavily on protoplast fusion methods, which have stability and efficiency problems. This team's goal is to modify the method and quickly produce a strain of S. cerevisiae combined with the P. stipitis genome through direct genome isolation and transformation.They started off by extracting the whole genome of P. stipitis, and inserting it into S. cerevisiae by electroporation. They then grew the amalgam strain in conditions that S. cerevisiae would not tolerate and obtained eight hybrid strains, which they evaluatated for ethanol production in a xylose containing broth. They picked the crem de le crem strain, F1-8, for a second round of genome reshuffling.In this second go round; F1-8 had an extracted genome of S. cerevisiae transferred into it. The new strain was then screened on YNBXE selective plates and three positive colonies were obtained, with the strain ScF2 being the most competent ethanol producer. To see how this technique worked compared to traditional protoplast fusion methods normally used they also constructed hybrid strains of F1-8 an S. cerevisiae via that technique, they all died on the YNBXE.Then the team compared xylose fermentation of F1-8 and ScF2 with their parent strains. ScF2 showed an improved ethanol production over both F1-8 and P. stipitis. This causes the scientists to believe that their modified genomic shuffling method could help efficiently create yeast strains with enhanced ability for turning xylose into ethanol, as it did in the ScF2 strain.While ScF2 showed a medley of skill, including the fermentation of both glucose and xylose as well tolerance to sugars and ethanol, the researchers speculate that utilizing the new method in conjunction with rational metabolic engineering and directed evolution could lead to more improvement of the strain.Wei Zhang, & Anli Geng (2012). Improved ethanol production by a xylose-fermenting recombinant yeast strain constructed through a modified genome shuffling method Biotechnology for Biofuels DOI: 10.1186/1754-6834-5-46Photo Credit: WikiMedia contributor Masur... Read more »
Wei Zhang, & Anli Geng. (2012) Improved ethanol production by a xylose-fermenting recombinant yeast strain constructed through a modified genome shuffling method. Biotechnology for Biofuels. DOI: 10.1186/1754-6834-5-46
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