X-Message-Number: 8497
Date: Tue, 26 Aug 1997 22:26:03 -0700 (PDT)
From: Doug Skrecky <>
Subject: 15'th update on fly longevity experiments
This is the fifteenth update on my fly experiments. On day 43 all
flies were dead in the 4'th run. About all that was interesting here was
the relative performance of the control, paprika and purple yam bottles.
However I am not inclined to regard these results as being significant,
since the flies for these 3 bottles were derived from several different
old breeding bottles. To be "fair" the control bottle must come form the
same breeding bottles as the supplements it is used to compare with. From
now on I will be using several control bottles.
Fourth Run Survival
Supplement DAY 10 DAY 24 DAY 34 DAY 43
Control 100% 56% 0% all 0%
bactine 75 0 0
bactine 4X 50 0 0
garlic 20 0 0
garlic 4X 0 0 0
KCL 100 0 0
KCL 4X 71 0 0
mint listerine 0 0 0
mint listerine 4X 0 0 0
paprika 88 38 0
paprika 4X 50 0 0
pectin 40 0 0
plax 60 0 0
plax 4X 0 0 0
purple yam 86 48 5
purple yam 4X 52 5 0
salt 47 13 0
salt 4X 38 0 0
sterisol 0 0 0
sterisol 4X 0 0 0
viadent 0 0 0
viadent 4X 0 0 0
water reduced 50% 90 30 10
The results of the fifth run were characterized by exceptionally high
mortality rates, in comparison with runs from earlier this year. I
attribute this difference to the fact that a heat wave hit my native
Vancouver, BC and the average temperature the flies were exposed to, rose
first above 80 degrees and then on some days to above 90 degrees. A short
exerpt from my fly longevity database reveals the strong link between
temperature and average life span of drosophilia melanogaster.
Temperature Life Span
52 F 152 days
64 130
68 81
70 86
77 62
81 42
86 25
86 20
Given the above data I should have finished my first census of run #5
a little quicker, while most of the flies were still alive. However even
at this late date some useful data emerges, as well as a lesson I will
not soon forget.
The lesson is that several control bottles must be used to derive
useful data, when temperatures are high. I use several breeding bottles
(BBs) to provide enough flies for each run. There will always be some
variations in the average age of the flies in each bottle, depending on
how much breeding has occurred. These new BBs were "seeded" with parent
flies 29 days before run #5 was started. If no offspring were produced
all flies inside a breeding bottle will be over 29 days old. If a small
amount of breeding occurs the average age will be a little lower, while
if a lot of breeding occurs the average age will be much lower. While a
difference of (for example) 5 days in average age between BBs will not
have much impact if the life span of the flies is several months at cool
temperatures, it can have a large impact when high temperature reduces
this life span to just a few weeks, as has occurred with run #5. (I have
always recorded which BBs are used, but had not included this in my
updates as it did not seem to make any difference earlier. I also record
the order in which I supply the supplement bottles from a BB.
Surprisingly this order does not make any difference; even in the present
run.)
Fortunately I created 3 control bottles this time so some usable data
emerges. Unfortunately I had to use 4 BBs when breeding bottle #3 (BB#3)
ran out of flies before I could create a control from this breeding
bottle. Thus the data from the supplement bottles using flies from the
BB#3 are of relatively little value. However the total number of flies
provided by BB#3 and BB#1 are similar, so control#1 might be used as a
"reasonable" substitute. However even if control#2 is used, which
problably contains more younger flies, since more flies were bred in BB#2
than in BB#1 or BB#3, it can be seen that the lower dosage of the
"nontoxic" bactericide/sugars handily outperformed both control#1 and
control#2.
The much higher survival in control#4, I attribute to the huge number
of flies that were in BB#4. I did not use all of these. The existance of
control#4 is a very valuable check on any misguided enthusiam on my part
regarding carnosine. As I mentioned in the 14'th update carnosine is not
absorbed intact, but instead is broken down to B-alanine and l-histidine,
both of which have proven to be ineffective life-extenders in published
experiments. If anyone knows of a source of the stable carnosine
precursor acetylcarnosine please let me know. I would give some pretty
fair odds that this would significantly increase fly life span.
Of the supplements that did well in run#3, that were retested this
time, anise was a disappointment, paba was so-so, while malt and
activated charcoal again beat the averages. I could not be sure of the
number of dead flies in the high dose activated carbon bottle, but will
verify the total number of flies after they are all dead and I can open
the bottle without fear of losing some flies.
Although medium 4-24 contains some sucrose already, I suspect that a
little more of either this or other sugars reduces pathogen growth and
increases life span somewhat. The amino acids were a disappoinment as a
group, though proline looks to be worth retesting. Proline has been found
to increase the life span of the mutant Long Evans Cinnamon rat, which
suffers from excessive copper accumulation and is considered an animal
model of Wilson's disease. (Pharmacology Biochemistry and Behaviour
52(3): 509-515 1995
Fifth Run
Breed Day 16
Bottle# Supplement Alive Dead Survival
BB#1 control#1 2 18 10%
1 l-alanine 2 13 13
1 l-alanine 4X 0 14 0
1 anise 1 9 10
1 anise 4X 0 9 0
1 l-glutamine 2 13 13
1 l-glutamine 4X 0 22 0
1 malt 5 15 25
1 malt 4X 2 20 9
1 paba 2 11 15
1 paba 4X 0 9 0
1 total 16 + 153=169 10% (average)
2 control#2 5 18 22
2 l-cysteine 3 14 18
2 l-cysteine 4X 0 15 0
2 l-glycine 2 19 10
2 l-glycine 4X 0 15 0
2 l-isoleucine 3 25 11
2 l-isoleucine 4X 1 30 3
2 l-leucine 2 16 11
2 dl-phenylalanine 2 22 8
2 dl-phenylalanine 4X 3 15 17
2 l-proline 4 11 27
2 l-proline 4X 5 14 26
2 l-threonine 4 14 22
2 l-threonine 4X 0 21 0
2 l-valine 3 20 13
2 l-valine 4X 3 15 17
2 total 40 + 286=326 12% (average)
3 activated charcoal 4 11 27
3 activated charcoal 4X 4 6? 40?
3 glucose 6 19 24
3 glucose 4X 5 18 28
3 l-leucine 4X 1 17 6
3 sorbitol 6 18 25
3 sorbitol 4X 3 13 19
3 sucrose 6 13 32
3 sucrose 4X 3 17 15
3 total 38 + 132=170 22% (average)
4 control#4 17 9 65
4 l-carnosine 9 14 39
4 l-carnosine 2X 18 15 55
4 l-carnosine 4X 10 20 33
4 l-carnosine 8X 6 33 15
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