YouTube is such a great teaching tool, and lgines has used it to share a very useful video series on how to use a microscope.
Part 1:
Part 2:
Part 3:
Recently I’ve been using YouTube to give class feedback on assignments as well as to post my thoughts about various areas of education and educational technology. How do you use YouTube in your teaching?
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It’s been another busy year at MicrobiologyBytes, with more than 300 posts this year, and over half a million page views, so here’s a whistle-stop tour of just some of the topics we’ve looked at during the last year:
January
February
March
April
May
June
July
August
October
November
December
So what’s going to happen in 2009? Watch the video, and keep reading MicrobiologyBytes!
The Final Inch is a collaborative effort between Google.org and Vermilion Films to document the final stages of the historic global effort to eradicate polio. The story told is as much about the messengers as the message. You’ll meet Munzareen Fatima, one of the thousands of community workers across India working to persuade reluctant families to vaccinate their children, and Dr. Ashfaq Bhat, who travels into the backwaters of India’s Ganges Basin by boat and foot to detect emerging cases of polio. Martha Mason and Mikail Davenport describe the paralyzing challenges of childhood polio, reminding us that polio was once endemic in the United States and Europe:
The Final Inch will air in the USA on HBO in 2009.
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The 14th October 2008 was the first ever Open Access Day. Open Access is a fundamental component of a new system for exchanging scholarly research results which aims to:
Still not convinced? Maybe this will help:
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As this year’s flu season gets underway in the northern hemisphere, new research finds that when it comes to flu vaccination, more appears to be better. Two new studies published in the open access journal PLoS Medicine show that increasing the number of people vaccinated against influenza can decrease the burden of the disease, and not just in the individuals receiving the vaccine.
Targeted vaccination programs, in which flu vaccine is recommended for particular groups at high risk of spreading or experiencing complications of influenza, are commonly implemented. In contrast, the Canadian province of Ontario initiated a universal immunization program in 2000, in which flu vaccination is promoted and provided free of charge to everyone over the age of 6 months. The first study evaluated the effect of this universal immunization program on influenza-associated health outcomes. The researchers analyzed national and provincial data from 1997 to 2004, to compare changes in Ontario’s flu outcomes before and after introduction of universal vaccination with outcomes in other provinces, which continued targeted vaccination programs. They found that, compared with other Canadian provinces, Ontario’s universal vaccination program was associated with reductions in influenza outcomes including flu-related deaths, hospitalizations, and visits to emergency departments and doctors’ offices. The results did suggest, however, that increasing immunization rates may not be as effective in reducing mortality and health care use in older people, particularly those over 75 years of age, compared to younger people. However, even with enhanced access to free flu vaccines in Ontario, only an estimated average of 38% of the overall household population reported receiving them, suggesting that protection of older people by higher immunization rates of younger contacts who might expose them to influenza may still be of benefit.
The second study further investigated the concept of herd immunity, by which immunization of some individuals protects the overall population by reducing exposure of those who are not immunized. Using a mathematical model to simulate spread of influenza in nursing homes, researchers found that increasing the number of health care staff who are vaccinated can protect additional patients from influenza. They calculated that increasing the proportion of vaccinated health care workers from zero to 100% in a 30-bed nursing home department would reduce patient infections by about 60%, and that vaccinating seven health care workers would on average prevent one patient from getting influenza. They also found that no level of health care worker vaccination guarantees complete herd immunity, suggesting that even at high levels of immunization, increasing the number of nursing home staff who are vaccinated against flu each year will further reduce risk to patients. The authors also note that random variation, which occasionally leads to large outbreaks, limits the ability of small vaccination trials to assess the actual relationship between health-care worker vaccination and patient risk of influenza.
Montage of high-speed video clips showing sporangiophore discharge in the fungus Pilobolus kleinii. The videos were obtained at camera frame rates of up to 250,000 fps. Each discharge is completed in less than 0.25 milliseconds; an eye blink takes 100 milliseconds, or 400 times longer! The music is Verdi’s Anvil Chorus. Credit: Yafetto et al
Microscopic coprophilous (dung-loving) fungi help make our planet habitable by degrading the billions of tons of faeces produced by herbivores. But the fungi have a problem: survival depends upon the consumption of their spores by herbivores and few animals will graze on grass next to their own dung. Evolution has overcome this obstacle by producing an array of mechanisms of spore discharge whose elegance transforms a cow pie into a circus of microscopic catapults, trampolines, and squirt guns. A new paper examines the operation of squirt guns that fire spores over distances of more than 2 metres. The researchers used high speed cameras running at up to 250,000 frames per second to capture these blisteringly fast movements. Spores are launched at maximum speeds of 25 meters per second impressive for a microscopic cell corresponding to accelerations of 180,000 g. In terms of acceleration, these are the fastest flights in nature. The paper is significant for a number of reasons. This is the first study utilizing ultra-high-speed video cameras to capture the events of spore discharge in ascomycete and zygomycete fungi. Previous investigators relied upon models to predict ballistic parameters and produced erroneous estimates of velocities and accelerations. These estimates were then used to suggest that pressures within the spore guns were very high. Fungal cells generate pressure by osmosis and the authors used a combination of spectroscopic methods to identify the chemical compounds responsible for driving water influx into the guns. These experiments showed that the discharge mechanisms in fungi are powered by the same levels of pressure that are characteristic of the cells that make up the feeding colonies of fungi. Therefore, the long flights enjoyed by spores result not from unusually high pressure, but from the way in which explosive pressure loss is linked to the propulsion of the spores. There are similarities between the escape of the spores and the expulsion of ink droplets through nozzles on inkjet printers. Another important aspect of the new work is the way that it has allowed the researchers to test different models for the effect of viscous drag on microscopic particles and identify limitations in previous approaches to modeling. This information is very important for future biophysical studies on spore and pollen movement, which have implications for the fields of plant disease control, terrestrial ecology, indoor air quality, atmospheric sciences, veterinary medicine, and biomimetics.
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The Fastest Flights in Nature: High-Speed Spore Discharge Mechanisms among Fungi. 2008 PLoS ONE 3(9): e3237
Background: A variety of spore discharge processes have evolved among the fungi. Those with the longest ranges are powered by hydrostatic pressure and include “squirt guns” that are most common in the Ascomycota and Zygomycota. In these fungi, fluid-filled stalks that support single spores or spore-filled sporangia, or cells called asci that contain multiple spores, are pressurized by osmosis. Because spores are discharged at such high speeds, most of the information on launch processes from previous studies has been inferred from mathematical models and is subject to a number of errors.
Methodology/Principal Findings: In this study, we have used ultra-high-speed video cameras running at maximum frame rates of 250,000 fps to analyze the entire launch process in four species of fungi that grow on the dung of herbivores. For the first time we have direct measurements of launch speeds and empirical estimates of acceleration in these fungi. Launch speeds ranged from 2 to 25 meters per second and corresponding accelerations of 20,000 to 180,000 g propelled spores over distances of up to 2.5 meters. In addition, quantitative spectroscopic methods were used to identify the organic and inorganic osmolytes responsible for generating the turgor pressures that drive spore discharge.
Conclusions/Significance: The new video data allowed us to test different models for the effect of viscous drag and identify errors in the previous approaches to modeling spore motion. The spectroscopic data show that high speed spore discharge mechanisms in fungi are powered by the same levels of turgor pressure that are characteristic of fungal hyphae and do not require any special mechanisms of osmolyte accumulation.
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Bioremediation is a process which uses microorganisms or their enzymes to return the natural environment altered by contaminants to its original condition.
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Internet for Microbiology
Small Things Considered
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Virology
