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1.
Evolution of the immunodominant domain of the circumsporozoite protein gene from Plasmodium vivax. Implications for vaccines 总被引:5,自引:0,他引:5
V F de la Cruz A A Lal J A Welsh T F McCutchan 《The Journal of biological chemistry》1987,262(14):6464-6467
Recent work directed toward the development of a malarial vaccine has focused on the identification and production of the immunodominant repeating peptide of the circumsporozoite protein of the human malaria parasites as an antigen. An important factor which relates to the usefulness of this antigen in a vaccine is the rate at which the molecule changes in sequence. We have determined the sequence and arrangement of the repeating epitope of the circumsporozoite protein gene from a Plasmodium vivax isolate from La Paz, El Salvador (Sal-I). This is compared with a portion of the previously published sequence of the circumsporozoite protein gene from a P. vivax isolate from Belém, Brazil. The genes appear to be very similar in the repeat region. There are 20 similar repeating units in the El Salvador strain and only 19 units are conserved in the Brazilian strain. Following this there are degenerate repeats in both strains. Even the pattern of silent mutations in the repeat area are similar; however, they are not necessarily in the identical location and appear to have shifted. The data suggest that the repeat region of these genes may be evolving by an accelerated mechanism(s). Such a phenomenon could severely decrease the long-term efficacy of a repeat-based anti-sporozoite vaccine. 相似文献
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5.
Neutron structure factors of in-vivo deuterated amorphous protein C-phycocyanin 总被引:1,自引:1,他引:0 下载免费PDF全文
Neutron powder diffraction measurements of fully deuterated protein C-phycocyanin have been made at three temperatures, 295, 200, and 77 K, using dry and partially hydrated samples. The average coherent structure factors and the corresponding radial distribution functions d(r) are determined. The changes in d(r) functions observed in hydrated samples depend strongly on the level of hydration and most of these changes are due to water-protein interactions. At 0.365 gram D2O per gram of protein, the water crystallized into hexagonal ice at 200 K and below, but at 0.175 gram D2O per gram of protein, no crystallization of water was observed. At the higher hydration a peak appears in the radial distribution function which indicates that the average distance of the water molecule in the first hydration shell from the amino acid residues is 3.5 Å. 相似文献
6.
Two new compounds G and H isolated from the roots of Costus speciosus have been characterized as 8-hydroxytriacontan-25-one and Me tritriacontanoat 相似文献
7.
Summary A series of factoral experiments involving the effects of gravel concentration in the subsoil horizon, the effect of inter-gravel
bulk density, the depth of the surface soil above the gravel horizon and the interaction between soil moisture regime and
gravel concentration, on growth and development of maize roots were conducted in the greenhouse. Increasing sub soil gravel
concentration decreased the total porosity and the available waterholding capacity. Though the root growth of maize seedlings
was adversely affected by gravel concentration above 20 per cent, lower concentration of gravels had a beneficial effect on
roots. The root development and the leaf concentration of N, P and K improved with increasing depth of surface soil above
the gravel horizon. The symptoms of mechanical impedance, such as thickening of root tips and profuse branching behind the
tip were commonly observed on the root axis penetrating the gravelly horizon. re]19750916 相似文献
8.
Rats withdrawn from continuous morphine infusion showed reliable occurrence of withdrawal body shakes. This sign of narcotic withdrawal was inhibited by the neuroleptic drug, (+) butaclamol. (?) Butaclamol was inactive. (+) Butaclamol activity was not antagonized by naloxone (5 mg/kg). The anti-withdrawal mechanism of (+) butaclamol is discussed in terms of effects on dopamine and narcotic receptors.The butyrophenone neuroleptic, haloperidol, has been used successfully to reduce signs of narcotic withdrawal in laboratory animals (1–4) and human addicts (5). Other neuroleptics of the butyrophenone type also show anti-withdrawal action (6, 7). The mechanism of action of these neuroleptics in blocking narcotic withdrawal is not understood. Butaclamol is a new neuroleptic drug that is available in two enantiomers and only (+) butaclamol possesses neuroleptic activity (8–10). Because of its demonstrated stereo-specificity in producing its pharmacological action, we employed this drug to establish specificity of action of neuroleptics in blocking narcotic withdrawal. 相似文献
9.
T K Chatterjee A Chakraborty M Pathak G C Sengupta 《Indian journal of experimental biology》1992,30(10):889-891
Extract of C. asiatica (Linn.) inhibited significantly gastric ulceration induced by cold and restraint stress (CRS) in Charles-Foster rats, Antiulcer activity of plant extract was compared with famotidine (H2-antagonist) and sodium valproate (anti-epileptic). Plant extract, formotidine and sodium valproate showed a dose dependent reduction of gastric ulceration. Plant extract increased brain GABA level which was also dose dependent. Pretreatment with bicuculline methiodide (specific GABAA-antagonist) at the dose level of 0.5 mg/kg im, reversed the antiulcerogenic activity of both plant extract and sodium valproate. Bicuculline as such did not induce gastric ulceration in normal rat. 相似文献
10.
Stage-specific ribosomal RNA expression switches during sporozoite invasion of hepatocytes 总被引:2,自引:0,他引:2
J D Zhu A P Waters A Appiah T F McCutchan A A Lal M R Hollingdale 《The Journal of biological chemistry》1990,265(21):12740-12744