Don’t let the sun go down on me

Total Solar eclipse 1999 in France.

Image via Wikipedia

An article from the weird side of science, via the ever amusing NCBI ROFL blog.  Some intrepid scientists wondered what happens to microorganisms during a total solar eclipse. Researchers at the Institute of Medical Sciences, Mangalore, India waited until a total solar eclipsed occurred in their vicinity. On 15 January, 2010, their patience was rewarded with an eclipse that lasted for several hours, with a period of totality of around 10 minutes.

The experiment was simple: they took nutrient agar slants of Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Candida albicans, and exposed them to sunlight (very dim) during the eclipse, and to normal sunlight. Following exposure, cultures were streaked onto blood agar to isolate single colonies. These colonies were then assayed for antimicrobial sensitivity to a panel of 6 antibiotics using the Kirby-Bauer assay.

Here is the data for E. coli:
Antibiotics Normal sunlight (mm) Solar eclipse phase (mm)
Aztreonam (30 μg) 24 22
Amikacin (30 μg) 24 22
Piperacillin (100 μg) 24 21
Ceftazidime (30 μg) 25 25
Ciprofloxacin (5 μg) 40 37

Well, as you can see, there’s not much difference.  I didn’t notice any standard error notations in the table, and the methods doesn’t give an indication of replicates in the study. The researchers indicate that there were “morphological” changes in the appearance of organism by microscopy, but do not include any photographs in the report.

An experiment was performed with the yeast, Candida albicans, which they call a comet assay to analyze the integrity of DNA using a method I am not familiar with. With this assay, they were unable to detect any significant changes in the yeast DNA, and end their results with this comforting statement:

which indicates that there may be no major impact of solar eclipse on human beings.

Good to know there, because in May 2012 (2012!!!!!) there will be a partial eclipse over most of the southern half of North America. I was planning on being in Europe then, just in case.

BONUS: Click through to the Pubmed article linked above. Find something, anything that might lead you to have a problem with the study.


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on April 12, 2011, in Bogus!, Bonus!. Bookmark the permalink. 8 Comments.

  1. Besides the obvious point that there are “no major inpact of solar eclipses on human beings” (every 12 hours day turns into night when the earth eclipses the sun, if that were somehow harmful I think after several million years of that human wouldn’t be in good shape). The conclusion its stated “we could infer that exposure to solar eclipse does help in the favor of microbes and man.” Where does that come from? I thought their results showed no notable difference? Also “Further study is needed in this area to use solar eclipse therapeutically to enhance the immune system and targeting the destruction of genesis of malignant cells thus, to alleviate the suffering of mankind.” I don’t know specically what all that means, but “using eclipses to enhance the immune system” sounds like pseudoscience to me. They also used normal light as their control. What does that mean specifically? In normal conditions, weather clouds could pass by block light, and create the same condtions as an eclipse.

    • While I was reading this article, I kept on thinking that we all go through an eclipse every single day; it’s called “night.”

  2. The study seems like a complete joke due to the vague details or complete lack of details given by the study. The study also notes that fungal species showed a definite change in their morphology but does not give any quantitative results in order to make any sort of conclusion. The study does not record how much sunlight the slants were exposed to in order to provide an analysis.

    • The study is a bit short on details, but I will give the authors the benefit of the doubt for sunlight exposure. The article does indicate how long the slants were exposed to eclipse conditions, and I would assume that the sunlight slants were exposed for a comparable time.

  3. What evidence do they have for this “definite change” in morphology?
    I can understand if there was a constant absence of sunlight over a long period, and how that would affect the results. The sun was fully covered for only ten minutes. . .maybe the researches should do an experiement during the night when the organisms are not exposed to light at all? I feel that results would be more dramatic then.

  4. This study I think was thought of with good intentions but really I don’t think that they were going to find any substantial evidence of changes in microorganisms for this short amount of time. The study I feel like was set up all wrong and even though it would be cool or interesting to find that there are changes during an eclipse we basically can say that there is an eclipse every night when the sun goes down. There is less sun light when it is evening time then when there is an eclipse because there is still some amount of light shining from behind the moon. It also doesn’t seem like they were very careful about how they went to set up the experiment. They didn’t include specifics about how the agar plates were kept and from my understanding they were just left outside to be “exposed” to the eclipse which isn’t a very controlled environment if you ask me.

  5. I would have to agree with stephanie on this topic, this experiment could have had a ton of good intentions, but rather just flopped in the making. First off, the arguement was somewhat interesting, but they needed to go futher indepth of the subject because as Aaron mentioned earlier, we go through an eclipse every single day of our lives, at least here in PA, which is known as night. As I was reading through the report, the entire thing just lacked details. Details are the major factor of an experiment/lab report. There needs to be serious background information prior and during the test to come to a result. Along the lines of this topic, the conclusion said absolutely nothing except nothing happend. The conclusion is there is further what exactly happend and trying to explain why it happened. The writer’s thoughts on the matter could even be mentioned there, which was completely missing in this report. This writier needed to go further with their information, the surface was skimmed but the whole idea of a lab report is to further research an experiement and the outcomes reported. I don’t even think I could hand this in, I need lots more details for my reports.

  6. Lauren Stierstorfer

    I agree with some of the other people who have posted on this blog. There didn’t seem to be a lot of background research presented, or even a great deal of details on the actual experient. In the methods section, all it said was that nutrient agar slants were exposed to light. I feel that they should have taken into consideration, different temperatures and environmental conditions that could affect microorganisms. I don’t feel that this was a very thorough study, however it could just be that this article was written as a brief summary and some details were left out.

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