SoylentNews

Repeated Drying Cycles Can Form Protein-like Polymers

posted by janrinok on Tuesday July 21 2015, @03:57PM   
from the I-thought-the-answer-was-42 dept.

Phoenix666 writes:

Amino acids are just what their name implies: they have an acidic group on one side of the molecule and a nitrogen-containing amino group on the other. It's possible to link these two groups together in a reaction that releases a water molecule. Once linked, they're stable, but the reaction that links them isn't energetically favorable. So, people pondering the origin of life have wondered whether there was a pathway in which the bond could could form spontaneously.

One possible method for getting it to form would be for a solution of amino acids to dry out. As the solution becomes ever more concentrated, a reaction that produces a water molecule could become favorable even if it's expensive in purely energetic terms. But so far, the reaction conditions to get this to work have been rather extreme.

The researchers involved in the new work figured that the amino acids might be alone in these puddles as they dried out. A related chemical, called lactic acid, is thought to have been present on the early Earth. And that can undergo a polymerization reaction that releases water, very similar to that of the amino acids. The difference is that this reaction is more energetically favorable. Simply putting lactic acid on its own through four wet/dry cycles allowed chains of four or more units to form, all connected by what's called an ester bond.

The impressive part is what happens when you mix lactic acid with an amino acid: you start forming mixed chains of molecules. While the amino acid won't normally participate in these reactions, they can break the ester bond, essentially replacing one of the lactic acids. So, a few wet/dry cycles produces a chain that's a mix of lactic acids and amino acids.

The skirt of a geyser would be one place with frequent wet/dry cycles and plenty energy to boot. Did life begin next to Old Faithful?

---

Original Submission

• Re:Experimental Confound (Score: 0) by Anonymous Coward on Tuesday July 21 2015, @07:27PM

  by Anonymous Coward on Tuesday July 21 2015, @07:27PM (#212061)

  Good point. I couldn't find a more recent comparable number using a quick search but it sounds like the problem continues:

  Although the discovery of these "HeLa contaminants" prompted immediate alarm, how aware are cell culturists today of the threat of cell line cross-contamination? To answer this question, we performed a literature search and conducted a survey of 483 mammalian cell culturists to determine how many were using HeLa contaminants without being aware of their true identity and how many were not using available means to ensure correct identity. Survey respondents included scientists, staff, and graduate students in 48 countries. HeLa cells were used by 32% and HeLa contaminants by 9% of survey respondents. Most were also using other cell lines; yet, only about a third of respondents were testing their lines for cell identity. Of all the cell lines used, 35% had been obtained from another laboratory instead of from a repository, thus increasing the risk of false identity. Over 220 publications were found in the PubMed database (1969-2004) in which HeLa contaminants were used as a model for the tissue type of the original cell line. Overall, the results of this study indicate a lack of vigilance in cell acquisition and identity testing. Some researchers are still using HeLa contaminants without apparent awareness of their true identity. The consequences of cell line cross-contamination can be spurious scientific conclusions; its prevention can save time, resources, and scientific reputations.

  Beuhring 2004: http://www.ncbi.nlm.nih.gov/pubmed/15638703 [nih.gov]

  Cell-line misidentification is a continuing problem (see, for example, Nature 457, 935–936; 2009), with an estimated 15% or more of human cell lines not being derived from the claimed source. This means that billions of dollars have been wasted over the past 45 years on producing misleading or false data. Although a few progressive journals and funding bodies demand that cell lines be authenticated, this practice needs to become standard and universal.

  Masters 2012: http://www.ncbi.nlm.nih.gov/pubmed/?term=23235867 [nih.gov]

  Parent