X-Message-Number: 24260
Date: Wed, 16 Jun 2004 21:13:57 -0700 (PDT)
From: Doug Skrecky <>
Subject: 139'th update on fly longevity experiments

    This is the 139'th update of my fly longevity experiments. Average
temperature was 22.1 C during this run. Estimated maximal longevity using
the formula (363 - T*11.2) is 115 days.
    This run compares the effects of various sugars. Sugars exert a mild
antibacterial effect via increased osmotic stress. However increasing the
sugar content, and not adding any additional water can also stress the
flies, as well as bacteria.
    At equivalent doses glucose outperformed both fructose, as well as
sucrose, which itself is 50% fructose and 50% glucose. The result with 4
tsp fructose indicates that high doses might be optimal. However since
addition of any supplements may also increase osmotic load, if sugars
become a standard additive to the fly food, the dosage should be
conservative so as to avoid possible dehydration problems. On the other
hand, at low sugar levels osmotic effects may account for some of the
benefit of some supplements.
    I also checked sterols out again, with a little added sugar to help
prevent sterol induced wetting of the fly food. Unfortunately the dosage
of sugar was inadequate to prevent this wetting, and so once again sterols
caused a reduction in survival.

Run #139               Percent Survival on Day
supplement         3  10 17 25 35 41 47 52 63 68 75 80 89 94 99 104
___________________________________________________________________
control one       98  95 81 72 47 37 30 19  9  2  0  -  -  -  -   -
control two      100  87 73 67 57 43 37 33 10 10  0  -  -  -  -   -
fructose 1/4 tsp  94  80 63 69 66 60 46 31 14  9  3  3  0  -  -   -
fructose 1/2 tsp 100  79 79 67 67 58 63 42 13 13  8  8  4  0  -   -
fructose 1 tsp   100  90 86 79 76 69 62 55 35 28 10  7  0  -  -   -
 +sterols 432 mg  97  82 62 50 24  9 12  9  3  3  0  -  -  -  -   -
fructose 2 tsp   100  96 86 86 82 79 71 61 32 18  7  0  -  -  -   -
fructose 4 tsp   100  83 83 83 80 80 77 77 73 63 33 30 10  0  -   -
glucose 1/2 tsp  100  88 81 69 59 53 53 47 47 41 22  3  3  3  3   0
glucose 2 tsp    100  96 85 82 78 78 78 78 63 63 56 41 26  7  7   0
sucrose 1/2 tsp  100  91 64 36 36 36 36 27 27 27  9  9  5  5  5   0
sucrose 2 tsp    100 100 95 90 85 90 80 70 50 35 15 15  0  -  -   -

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=24260