Table 1.

Molar percentages and relative specific radioactivities of organic LMM in water extracts of radiolabeled orb webs from Argiope fed [U-14C]glucose or a solution containing L-[35S]methionine and L-[35S]cysteine

Argiope aurantiaArgiope trifasciata
35S-labeled webs14C-labeled webs14C-labeled webs
Readily synthesized LMM
    Alanine0.01±0.010NA0.05±0.0270.57±0.12288.2 (51.4-151)i
    Glycine0.53±0.306NA2.3±0.4937.8 (27.1-52.9)d2.7±0.9740.2 (23.4-69.0)h,i
    GABamide57.6±2.51NA53.9±1.8919.6 (14.0-27.5)c,d11.0±2.5810.2 (5.97-17.6)e,f,g
Moderately synthesized LMM
    N-AcetylputrescineNDNAND24.9±3.173.53 (2.06-6.05)c,d,e
        Putrescine moiety2.70 (1.57-4.63)c,d
        Acetyl moiety5.05 (2.94-8.67)d,e,f
    Taurine1.5±0.4566.91 (58.0-77.2)b0.95±0.2071.7±0.21
    N-Acetyltaurine12.6±0.6652.9 (47.8-58.5)a15.2±1.2212.9 (9.19-18.0)c5.6±0.5414.1 (8.24-24.2)f,g,h
        Taurine moiety2.24 (1.60-3.14)b1.15 (0.67-1.97)b,c
        Acetyl moiety23.1 (16.5-32.3)c,d27.0 (15.7-46.3)g,h,i
    Isethionic acid8.3±1.0747.1 (42.5-52.1)a7.6±1.212.08 (1.49-2.91)b26.7±1.490.69 (0.40-1.18)b
Poorly synthesized LMM
    Choline15.7±2.00NA17.2±0.960.19 (0.14-0.27)a23.3±0.620.16 (0.09-0.27)a
    Glycine betaine3.8±0.35NA2.8±0.233.5±0.77
  • See text for explanation of different categories of LMM (Readily, Moderately, and Poorly synthesized).

    Web collections: A aurantia, N=4 for both 35S- and 14C-labeled webs; for A. trifasciata, N=3 web collections.

    Molar percentages (Mole%, mean ± s.e.m.) in this table were calculated based on the 11 organic LMM constituting 100% of the LMM. Elsewhere, molar percentages were calculated based on the 11 organic LMM plus H2PO4- constituting 100% of the LMM.

    RSR, relative specific radioactivity (mean and 95% confidence interval). *For 35S-labeled web extracts, specific radioactivities were normalized within each web collection by expressing the specific activity of each LMM as a percentage of the sum of the specific activities of NAT+Ise (c.p.m./mole S). For 14C-labeled web extracts, normalized specific activities were similarly expressed as a percentage of the sum of the specific activities of Cho+GAB+Gly+NAT+Tau moiety of NAT+acetyl moiety of NAT+Ise (i.e. the constitutents for which we have specific activity data in both Argiope species) (c.p.m./mole C). Thus, the mean specific activities reported from the 14C-labeled webs are directly comparable between the two species.

    Within the webs of a single species labeled with a single radioisotope, specific radioactivities differed significantly (P<0.05) from each other if they show no superscript letters in common. See `Statistical Analyses' in Materials and methods for more details.

    NA, not applicable; ND, none detected by 1H-NMR.

  • 1 N=2 (taurine was not adequately resolved in the other two web collections).