PROLINE BETAINE: A UNIQUE OSMOLYTE IN AN EXTREMELY EURYHALINE OSMOCONFORMER
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چکیده
منابع مشابه
Ionic basis of axonal excitability in an extreme euryhaline osmoconformer, the serpulid worm Mercierella enigmatica (Fauvel).
Despite the extreme fluctuations in blood concentration experienced by this marine osmoconformer, essentially 'conventional' ionic mechanisms are involved in conduction by the giant axons in isosmotic conditions. The resting axonal membrane approximates to an ideal potassium electrode, with a 58-8 mV slope for decade change in [K+]O above 10 mM. The action potential overshoot shows a 55-8 mV de...
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Chlorella autotrophica (Clone 580) grows over the external salinity range of 1 to 400% artificial sea water (ASW), can photosynthesize over the range from 1 to 600% ASW, and survives the complete evaporation of seawater. The alga grown at high salinities shows an increase in cell volume and a small decrease in cell water content. Measurements of ion content were made by neutron activation analy...
متن کاملRegulation of levels of proline as an osmolyte in plants under water stress.
Compatible osmolytes are potent osmoprotectants that play a role in counteracting the effects of osmotic stress. Proline (Pro) is one of the most common compatible osmolytes in water-stressed plants. The accumulation of Pro in dehydrated plants is caused both by activation of the biosynthesis of Pro and by inactivation of the degradation of Pro. In plants, L-Pro is synthesized from L-glutamic a...
متن کاملProline betaine uptake in Sinorhizobium meliloti: Characterization of Prb, an opp-like ABC transporter regulated by both proline betaine and salinity stress.
Sinorhizobium meliloti uses proline betaine (PB) as an osmoprotectant when osmotically stressed and as an energy source in low-osmolarity environments. To fulfill this dual function, two separate PB transporters, BetS and Hut, that contribute to PB uptake at high and low osmolarity, respectively, have been previously identified. Here, we characterized a novel transport system that mediates the ...
متن کاملBetS is a major glycine betaine/proline betaine transporter required for early osmotic adjustment in Sinorhizobium meliloti.
Hybridization to a PCR product derived from conserved betaine choline carnitine transporter (BCCT) sequences led to the identification of a 3.4-kb Sinorhizobium meliloti DNA segment encoding a protein (BetS) that displays significant sequence identities to the choline transporter BetT of Escherichia coli (34%) and to the glycine betaine transporter OpuD of Bacillus subtilis (30%). Although the ...
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ژورنال
عنوان ژورنال: The Biological Bulletin
سال: 1984
ISSN: 0006-3185,1939-8697
DOI: 10.2307/1541294