

Tag: Salmonella

Data update: How dyestuffs make stuff die



Wainwright tells us:







Most of it is in German, which I will ignore.


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Here’s Table 1.




Let’s leave it as a table.









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Table 1:






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Gallery: Cockroach feeding contraptions

Cockroaches are disgusting. The presence of roaches indicates squalid and germ-ridden conditions. However… do the roaches themselves contribute to the pestilence? Or are they merely a symptom? Or perhaps they are actually beneficial, as they might be able to destroy the germs in their digestive tract.

This is the sort of question that scientists needed to answer. Dr. Stanley Wedberg (1913-2003) of the University of Connecticut created an optimal system for such studies. The cockroach would be immobilized on a block of paraffin in what looks like a comfortable reclining position. This was suited for controlling its food intake to contain known amounts of bacteria, and monitoring its excretions to see how much bacteria remained.

Published in 1947, his system was based on one demonstrated a year earlier by Hubert Frings, a postdoc at Edgewood Arsenal in Maryland. What?

Yes, Edgewood Arsenal, now part of the Aberdeen Proving Grounds, was basically the US Army’s chemical plant, and included a Medical Research Laboratory, which in turn included a division of entomology and insect physiology for some reason. Hubert Frings’s mentor was the head of entomology, Dr. Leigh Chadwick.

Anyway, Frings (who was later quoted in Sports Illustrated on the subject of how to keep birds away from rocket sleds) was using fixed feeding rigs to get insects to ingest chemicals, to measure toxicity. In the paper that demonstrated the cockroach apparatus, his aims were even less sinister, basically looking at which salt solutions cockroaches prefer to drink, and figuring out how high of a concentration is necessary for roaches to prefer sucrose to water.

Wedberg improved the mechanism by putting the roach on its back, which reduced regurgitation and made it more comfortable (yes, both papers use the word “comfort” with regard to how the roach feels). And just as significantly, he decided to use a different roach species, one that was bigger (meaning food and excreta could be measured more accurately), more docile, and had a broad, flat body type well suited for attaching to a block of paraffin.

Wedberg’s choice of Blaberus cranifer as the experimental model cockroach did not catch on, but his technique did, and therefore many subsequent papers just referred to Wedberg and Clarke (1947) or Wedberg, Brandt and Helmboldt (1949) instead of including their own pictures of their own roach restraint systems. But several scientists did seek to show the reader what their apparatus looked like.

Here are a few such pictures. There are probably a lot more in the hardcore entomology journals (J Med Entomol, J Econ Entomol) whose archives I can’t access.

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From Frings H (1946), Gustatory thresholds for sucrose and electrolytes for the cockroach, Periplaneta americana (Linn.). J Exp Zool 102:23-50.


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From Wedberg SE, Clarke NA (1947), A simple method for controlled experimentation on the passage of microorganisms through the digestive tract of insects. J Bacteriol 54:447-450.


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From Mackerras IM, Pope P (1948), Experimental Salmonella infections in Australian cockroaches. Austral J Exp Biol Med Sci 26:465-470.


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From Wedberg SE, Brandt CD, Helmboldt CF (1949), The passage of microorganisms through the digestive tract of Blaberus cranifer mounted under controlled conditions. J Bacteriol 58(5):573-578.


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From Leibovitz A (1951), The cockroach, Periplaneta americana, as a vector of pathogenic organisms. I. The acid-fast organisms. Bulletin of the Pan-American Sanitary Bureau 30:30-41.


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From Julseth RM, Felix JK, Burkholder WE, Diebel RH (1969), Experimental transmission of Enterobacteriaceae by insects. I. Fate of Salmonella fed to the hide beetle Dermestes maculatus and a novel method for mounting insects. Appl Env Microbiol 17(5):710-713. [Well, they look like roaches. Small roaches.]


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From Klowden MJ, Greenberg B (1976), Salmonella in the American cockroach: Evaluation of vector potential through dosed feeding experiments. J Hyg, Camb 77(1):105-111.


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Pubmedwhack: Coproagglutinins

You may be familiar with the concept of a “Googlewhack”, which in common parlance is a word or phrase that returns exactly one result when typed into Google. Wikipedia claims it must be two words, without quotation marks, and a single word or a phrase in quotation marks is not a “Googlewhack” but is a “Googlewhackblatt” or some other hair-splitting neologism. But the word was invented and given that definition a decade ago, and I think the original definition is no longer practical.

So a Pubmedwhack would be a phrase that, when typed into Pubmed, the indispensible bioscience citation database, gives exactly one result. Like “vampyric” (1), or “great blue heron embryos” (2).

One example from immunology is “coproagglutinins”. Search for that and all you get is a 1951 paper (3) (subscription required) from the U.S. Army’s 406th Medical General Laboratory, which was headquartered in Tokyo.


In this study they were trying to diagnose which type of organism was causing bloody diarrhea, by looking for antibodies in the diarrhea itself. Anti-Shigella antibodies suggest that it’s a Shigella infection. Anti-Corynebacterium antibodies suggest diphtheria. And so on. “Copro-” is, of course, the prefix referring to feces, as in “coprolite” (4). The word “coproantibodies” is found in a few dozen titles and abstracts, including 20 or so from the 21st century. So it’s not a ridiculous technique. But this is the only paper to combine the new (as of 1951) concept of antibodies measured in feces, with the old (as of a few years later) word “agglutinins”.

To detect antibodies at this time, we had moved beyond complement fixation and amboceptors and whatnot. People doing serological tests could mix serum, or in this case fecal extracts, with a sample of Shigella paradysenteriae. If the extract contained antibodies specific for that bacteria, they would bind each other and form aggregates, making the solution cloudy.

That’s agglutination. You do it to detect agglutinins, which are the kind of antibody that agglutinates. Although agglutinins, like amboceptors, are best described as simply “antibodies”.

Now we have various other techniques for detecting antibodies. So to call them “agglutinins” just because you’re using agglutination to detect them adds confusion.

The word “agglutinins” is still used in the 21st century, to describe the antibodies of certain autoimmune diseases, as in this Blood editorial (5). We all make some antibodies against our own red blood cells. With too many anti-RBC antibodies, this can lead to the RBCs aggregating and being destroyed by complement. Especially in cold weather and in the extremities, hence the name “cold agglutinins”.

Science is not aware of any cold coproagglutinins.

Another way to tell Salmonella from Shigella (click for source)

Another way to tell Salmonella from Shigella (click for source)

1. Almond BR (2007). Monstrous infants and vampyric mothers in Bram Stoker’s “Dracula”. Int J Psychoanal 88:219-235.

2. Hart LE (1991). Dioxin contamination and growth and development in great blue heron embryos. J Toxicol Environ Health 32:331-344.

3. Barksdale WL, Ghoda A, Okabe K (1951). Coproagglutinins in ulcerative colitis. J Inf Dis 89:47-51.

4. Steve (2010). Coprolites: A few words on prehistoric turds., accessed November 1, 2013.

5. Stone MJ (2008). Heating up cold agglutinins. Blood 116:3119-3120.