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1.
Tissue specific plant lectins were searched in the seeds of 44 tropical trees of Kerala, India. Seeds of only 12 plant species
showed lectin activity. N-acetyl-D-galactosamine was the best inhibitor of lectin activity for the majority of the seeds.
Lectin activity in the seeds of 4 species were not inhibited by any of the mono- or polysaccharides used.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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A haemagglutinating material was isolated and purified from the phosphate buffered saline extract of the seeds of the jack
fruit using an immobilized N-aeetyl-D-galactosamine column. This material was composed of two iso-lectins of molecular masses
11 500 and 15 000. The lectins agglutinated native washed red blood cells of the human A, B and 0 groups and sheep, rabbit
and mouse erythrocytes. The lectins were found to be composed of single polypeptide chains and they contained no covalently
linked sugars. The lower molecular mass material was present in considerably greater quantity than the higher molecular mass
component. On isoelectric focussing on PAG the lectins gave a spread of components with calculated pI between 6.0 and 8.3. 相似文献
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Internal Representations of Temporal Statistics and Feedback Calibrate Motor-Sensory Interval Timing
Humans have been shown to adapt to the temporal statistics of timing tasks so as to optimize the accuracy of their responses, in agreement with the predictions of Bayesian integration. This suggests that they build an internal representation of both the experimentally imposed distribution of time intervals (the prior) and of the error (the loss function). The responses of a Bayesian ideal observer depend crucially on these internal representations, which have only been previously studied for simple distributions. To study the nature of these representations we asked subjects to reproduce time intervals drawn from underlying temporal distributions of varying complexity, from uniform to highly skewed or bimodal while also varying the error mapping that determined the performance feedback. Interval reproduction times were affected by both the distribution and feedback, in good agreement with a performance-optimizing Bayesian observer and actor model. Bayesian model comparison highlighted that subjects were integrating the provided feedback and represented the experimental distribution with a smoothed approximation. A nonparametric reconstruction of the subjective priors from the data shows that they are generally in agreement with the true distributions up to third-order moments, but with systematically heavier tails. In particular, higher-order statistical features (kurtosis, multimodality) seem much harder to acquire. Our findings suggest that humans have only minor constraints on learning lower-order statistical properties of unimodal (including peaked and skewed) distributions of time intervals under the guidance of corrective feedback, and that their behavior is well explained by Bayesian decision theory. 相似文献
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Leaf explants of Solanum khasianum regenerated on MS medium containing 2, 4-D (3 mg/l) and kinetin (1 mg/l). Shoots could be induced from these calli on medium containing BAP (3 mg/l) alone. Rhizogenesis of these shoots occurred when transferred to medium containing 2 mg/l NAA. The yield of solasodine — a pharmaceutically important compound, from 4-month-old callus tissue was remarkable at 2 per cent of dry weight. 相似文献
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The psbQ gene encoding a 16-kDa polypeptide of the oxygen-evolving complex of photosystem II has been isolated from Arabidopsis thaliana and characterized. The gene consists of a 28 nucleotide long leader sequence, two introns and three exons encoding a 223-amino-acid precursor polypeptide. The first 75 amino acids act as a transit peptide for the translocation of the polypeptide into the thylakoid lumen. Expression studies show that the gene is light-inducible and expresses only in green tissues with high steady-state mRNA levels in leaves. Using this gene as a probe, restriction fragment length polymorphism between two ecotypes, Columbia and Estland, has also been detected. 相似文献
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