| 1. |
- Alfvén, Hannes
(författare)
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Filamentary structures
- 1986
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 231:4741, s. 907-908
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Björk, Glenn R, et al.
(författare)
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Prevention of translational frameshifting by the modified nucleoside 1-methylguanosine
- 1989
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Ingår i: Science. - 0036-8075 .- 1095-9203. ; 244:4907, s. 986-989
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Tidskriftsartikel (refereegranskat)abstract
- The methylated nucleoside 1-methylguanosine (m1G) is present next to the 3' end of the anticodon (position 37) in all transfer RNAs (tRNAs) that read codons starting with C except in those tRNAs that read CAN codons. All of the three proline tRNA species, which read CCN codons in Salmonella typhimurium, have been sequenced and shown to contain m1G in position 37. A mutant of S. typhimurium that lacks m1G in its tRNA when grown at temperatures above 37 degrees C, has now been isolated. The mutation (trmD3) responsible for this methylation deficiency is in the structural gene (trmD) for the tRNA(m1G37)methyltransferase. Therefore, the three proline tRNAs in the trmD3 mutant have an unmodified guanosine at position 37. Furthermore, the trmD3 mutation also causes at least one of the tRNAPro species to frequently shift frame when C's are present successively in the message. Thus, m1G appears to prevent frameshifting. The data from eubacteria apply to both eukaryotes and archaebacteria.
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| 3. |
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| 4. |
- Stern, J. H., et al.
(författare)
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Divalent Cations Directly Affect the Conductance of Excised Patches of Rod Photoreceptor Membrane.
- 1987
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 236:4809, s. 1674-1678
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Tidskriftsartikel (refereegranskat)abstract
- Phototransduction in rod cells is likely to involve an intracellular messenger system that links the absorption of light by rhodopsin to a change in membrane conductance. The direct effect of guanosine 3',5'-monophosphate (cGMP) on excised patches of rod outer segment membrane strongly supports a role for cGMP as an intracellular messenger in phototransduction. It is reported here that magnesium and calcium directly affect the conductance of excised patches of rod membrane in the absence of cGMP and that magnesium, applied to intact rod cells, blocks a component of the cellular light response. The divalent cation-suppressed conductance in excised patches showed outward rectification and cation-selective permeability resembling those of the light-suppressed conductance measured from the intact rod cell. The divalent cation-suppressed conductance was partly blocked by a concentration of the pharmacological agent L-cis-diltiazem that blocked all of the cGMP-activated conductance. Divalent cations may act, together with cGMP, as an intracellular messenger system that mediates the light response of the rod photoreceptor cell.
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| 5. |
- Wieloch, Tadeusz
(författare)
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Hypoglycemia-induced neuronal damage prevented by an N-methyl-D-aspartate antagonist
- 1985
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 230:4726, s. 681-683
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Tidskriftsartikel (refereegranskat)abstract
- The possibility that neuronal damage due to hypoglycemia is induced by agonists acting on the N-methyl-D-aspartate (NMDA) receptor was investigated in the rat caudate nucleus. Local injections of an NMDA receptor antagonist, 2-amino-7-phosphonoheptanoic acid, were performed before induction of 30 minutes of reversible, insulin-induced, hypoglycemic coma. Neuronal necrosis in these animals after 1 week of recovery was reduced 90 percent compared to that in saline-injected animals. The results suggest that hypoglycemic neuronal damage is induced by NMDA receptor agonists, such as the excitatory amino acids or related compounds.
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