. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 10 60 20 30 40 Hours at 21° C Figure 4. Interruption of heat dissipation during germination ofEunapiusfragilis gemmules by perfu- sion with nitrogen-saturated medium (nominally oxygen free). The period of oxygen deprivation is indi- cated on the figure observation implies that adenylate status is probably not compromised by the diapause period prior to reinitiation of differentiation. Otherwise, one would expect to see a substantial rise in ATP levels during the early stages of germination. Discussion Energy flows in gemmule
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 10 60 20 30 40 Hours at 21° C Figure 4. Interruption of heat dissipation during germination ofEunapiusfragilis gemmules by perfu- sion with nitrogen-saturated medium (nominally oxygen free). The period of oxygen deprivation is indi- cated on the figure observation implies that adenylate status is probably not compromised by the diapause period prior to reinitiation of differentiation. Otherwise, one would expect to see a substantial rise in ATP levels during the early stages of germination. Discussion Energy flows in gemmules of the freshwater sponge Eunapius fragilis differ between the states of diapause 01 E. Hours at Room Temperature Figure 5. Chemical measurements of ATP, ADP. and AMP ex- tracted from gemmules ofEunapiusfragilis at various points dunng germination. Values are expressed as means ±1 SE(n = 3). and post-diapause (germination). Diapausing gemmules exhibit an energy flow only 50% that of post-diapause gemmules at the beginning of germination, and this rate of heat flow is only 11% of that seen in post-diapausing gemmules at the point of cell emergence from the collag- enous capsules. Thus, diapause is characterized by a sub- stantial metabolic and developmental suppression. Nev- ertheless, there is still energy metabolism in this state of obligate (constitutive) dormancy when measured at 2\°C. Presumably, the energy flow during diapause would be depressed further by the low temperatures nat- urally experienced during the overwintering state. Gas- Table I A TP ADP ratios and adenylate energy charge in gemmules of Eunapius fragilis during germination Time at room temperature (h) ATP:ADP ratio" Energy charge" 0 ± ± 6 ± + 18 ± + 30 + ± 42 17. 55 ±* + 54 ± + a Values represent means ± 1 SE (n = 3). * Significantly different from hour 0 value (P = ), b
Size: 1832px × 1365px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
