Stephen H Loomis

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In this study we compare the ability of various amino acids to protect small unilamellar vesicles against damage during freeze/thaw. Liposomes were composed of 75% palmitoyloleoyl phosphatidylcholine and 25% phosphatidylserine. Damage to liposomes frozen in liquid nitrogen and thawed at 20 degrees C was assessed by resonance energy transfer. Cryoprotection(More)
We have demonstrated that sugars and suger/zinc mixtures can be used to preserve the activity of dried phosphofructokinase (PFK) during long-term storage over CaSO4. After 9 weeks in the presence of either 200 mM sucrose or 200 mM trehalose little loss of PFK activity was noted, with almost 60% of the original prefreeze-dry activity recovered when samples(More)
Sponges can be found in fresh or saltwater habitats. As part of their life cycle, many sponges produce gemmules as a means of surviving environmental challenge. In most sponges, the gemmules contain cells that are initially in a state of metabolic arrest that is controlled by endogenous factors. This state is known as diapause. Following a period of(More)
Freshwater sponges produce gemmules during the fall as an adaptation to survive cold winters. Most gemmules are produced in a state of diapause and must undergo a vernalization period before diapause is broken and they enter the quiescence state. Quiescent gemmules will germinate if placed at room temperature. We examined the mechanism of germination in two(More)
Abstract Low temperatures limit the poleward distribution of many species such that the expansion of geographic range can only be accomplished via evolutionary innovation. We have tested for physiological differences among closely related species to determine whether their poleward latitudinal ranges are limited by tolerance to cold. We measured lower(More)
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