Studies on the fungal phytotoxin victorin: Structures of three novel amino acids from the acid hydrolyzate

Summary The host-selective phytotoxin victorin, produced by the fungusCochliobolus victoriae, was found to be at least partially peptidic in nature, and did not contain victoxinine. The exact mass of the M-H ion was measured by FABMS as 795.1877. Derivatives of three major acid hydrolysis products were isolated. The structures of the corresponding amino acids were assigned as 2S,3R-3-hydroxyleucine, 5,5-dichloroleucine, and 3-hydroxylysine. A into victorin by the fungus in vivo.     

Antimutagenic unusual amino acids from plants

Five unusual amino acids were identified as antimutagens against spontaneous mutation of Salmonella typhimurium TA100: L-azetidine-2-carboxylic acid (1) from Liliaceae plants, alpha-(methylenecyclopropyl)glycine (2) from Litchi chinensis seeds, and 2-amino-4-methylhex-5-ynoic acid (3), hypoglycin A (4), and (2S,4R)-2-amino-4-hydroxyhept-6-ynoic acid (5) from Euphoria longana seeds. The absolute stereochemistry of 5 was determined by its chiral synthesis from L-allylglycine, proving that 5 is the C-4 epimer of the amino acid previously isolated from dried longan seeds.     

Antimutagenic unusual amino acids from plants

Summary Five unusual amino acids were identified as antimutagens against spontaneous mutation ofSalmonella typhimurium TA100: L-azetidine-2-carboxylic acid (1) from Liliaceae plants, -(methylenecyclopropyl)glycine (2) fromLitchi chinensis seeds, and 2-amino-4-methylhex-5-ynoic acid (3), hypoglycin A (4), and (2S, 4R)-2-amino-4-hydroxyhept-6-ynoic acid (5) fromEuphoria longana seeds. The absolute stereochemistry of5 was determined by its chiral synthesis from L-allylglycine, proving that5 is the C-4 epimer of the amino acid previously isolated from dried longan seeds.This work was partly supported by a Grant-in-Aid form the Ministry of Education, Science, and Culture, Japan, No. 57740283 (to HK).     

A comparison of methods for bootstrapping in the local level model

Bootstrap in time series models is not straightforward to implement, as in this case the observations are not independent. One of the alternatives is to bootstrap the residuals in order to obtain the bootstrap series and thus use these series for inference purposes. This work deals with the problem of assessing the accuracy of hyperparameters in structural models. We study the simplest case, the local level model, where the hyperparameters are given by the variances of the disturbance terms. As their distribution is not known, we employ the bootstrap to approximate the true distribution, using parametric and non‐parametric approaches. Bootstrap standard deviations are computed and their performances compared to the asymptotic and empirical standard errors, calculated using a Monte Carlo simulation. We also build confidence intervals to the hyperparameters, using four bootstrap methods and the results are compared by means of the length, shape and coverage probabilities of the intervals. Copyright © 2002 John Wiley & Sons, Ltd.     

Conformations of amino acids calculated from molecular orbital theory

Zusammenfassung Die Konformation einiger natürlicher Aminosäuren wird auf Grund einer erweiterten Hückel-Molekular-Orbital-Theorie berechnet.

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Recipient of a Public Health Service Research Career Development Award No. AM1159.     

A new inhibitor of decarboxylase of aromatic amino acids

Zusammenfassung N-(DL-Seryl)-N-(2,3,4-trihydroxybenzyl)hydrazin (Ro 4-4602) bewriktin vitro starke Hemmung der Decarboxylase, die durch Pyridoxal-5-phosphat nicht und durch Dialyse nur wenig vermindert werden kann. Nach i.p. Applikation der Substanz kommt es zu starker Verminderung der Decarboxylase-Aktivität und zu mässiger Herabsetzung von 5-Hydroxytryptamin und Noradrenalin in verschiedenen Organen. Monoaminoxydase des Gehirns wirdin vivo durch Ro 4-4602 nicht beeinflusst.     

A comparison of adaptive structural forecasting methods for electricity sales

This paper presents the results of a study to determine whether new forecasting technologies might be of use to electric utilities for sales forecasting up to 3 years into the future. The methods considered included ordinary least squares on dynamic structural models, autocorrelated error models, adaptive variance and adaptive parameter models. Overall, the more adaptive models performed best, but most of the methods proved vastly superior to simple least squares models which do not take dynamics into account.     

A comparison of methods for the inactivation of third component of guinea-pig complement

Riassunto Sono stati esaminati comparativamente tre reagenti per la titolazione di C₃, rispettivamente allestiti con siero di cavia inattivato con zymosan, formalina e «Liquoid». Le differenze esistenti tra essi sono state analizzate e discusse in base alle attuali conoscenze sulla natura del terzo componente complementare.

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Supported in part by Contract DA-49-007-MD-696 with the Office of the Surgeon General, Department of the Army.     

Photochemical synthesis of amino acids from paraformaldehyde catalysed by inorganic agents

Riassunto Viene confermato che la sintesi fotochimica degli aminoacidi da paraformaldeide catalizzata da composti inorganici avviene sia in presenza sia in assenza di una sorgente inorganica di azoto fissato (aria). Inoltre viene dimostrato che i tipi di aminoacidi prodotti come la velocità di formazione dipendono dal catalizzatore usato.

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Supported in part by the Air Force Cambridge Research Laboratories, under Grant AF EOAR No. 63–116, through the European Office of Aerospace Research, United States Air Force.     

Polypeptides and Leuches' anhydrides from carbamic acid derivatives of C-activated amino acids

Zusammenfassung Durch katalytische Hydrierung von C-aktivierten Carbobenzoxyaminosäurederivaten, z. B. von gemischten Anhydriden und aktivierten Estern, werden via die Carbaminsäurederivate die entsprechenden Leuchsschen Anhydride und Polypeptide erhalten.

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This work was supported by grants from the National Institutes of Health, U.S. Public Health Service (G.M. 06579 and G.M. 08795).     

A forecasting comparison of classical and Bayesian methods for modelling logistic diffusion

A Bayesian procedure for forecasting S‐shaped growth is introduced and compared to classical methods of estimation and prediction using three variants of the logistic functional form and annual times series of the diffusion of music compact discs in twelve countries. The Bayesian procedure was found not only to improve forecast accuracy, using the medians of the predictive densities as point forecasts, but also to produce intervals with a width and asymmetry more in accord with the outcomes than intervals from the classical alternative. While the analysis in this paper focuses on logistic growth, the problem is set up so that the methods are transportable to other characterizations of the growth process. Copyright © 2001 John Wiley & Sons, Ltd.     

Concerning the free amino acids in amphibian development

Zusammenfassung Wir untersuchten Keime verschiedener Altersstadien vonTriton palmatus undTriton alpestris mit Hilfe der Papierchromatographie auf das Vorkommen von freien Aminosäuren und Polypeptiden. Im Gegensatz zu andern Autoren fanden wir solche in allen Stadien in nachweisbaren Konzentrationen. Ihre Zahl und Menge ändern sich im Lauf der Entwicklung.Asparaginsäure und Glutaminsäure kommen in jeder Altersstufe vor. Bei jungen Larven (Harrison 31–32) konnten wir neben andern Ninhydrin-positiven Substanzen auch Serin nachweisen. Bei ältern Larven (Harrison 40–44) treten Threonin, Alanin, Valin und Leuzin neu in Erscheinung. BeiTriton alpestris fanden wir in allen untersuchten Stadien einen Polypeptidkomplex, welcher in beiden verwendeten Lösungsmitteln eine hohe Wanderungsgeschwindigkeit aufwies. Er besteht aus: Asparaginsäure, Glutaminsäure, Serin, Glyzin, Thyrosin, Alanin und einer noch nicht identifizierten Aminosäure.Mit der Neurulation scheint eine Abnahme von Zahl und Menge der freien Aminosäuren und der Polypeptide verbunden zu sein. Furchung und Larvenentwicklung sind jedoch durch eine Zunahme gekennzeichnet.     

The asymmetry of the nucleotide bases and amino acids

Summary Due to the electric polarisation induced by the carbon and nitrogen atoms, the molecules of the nucleotide bases present a stereo-asymmetry. The DNA right-handed double helix is determined by the asymmetry of the nucleotide bases and it is concordant with the right-handed -helix of the polypeptide molecules formed by L-amino acids.     

Concerning the free amino acids in the hydroid tubularia

Résumé La composition de l'amine acide libre dans les deux espèces deTubularia a été examinée au moyen de la chromatographie. Les tissus d'hydranthe deT. crocea avaient 21 amines acides libres dont 18 ont été identifiées dans les hydrocauli et dans les hydranthes régénérés deT. crocea, 19 dans les hydranthes deT. spectabilis et 14 dans les hydrocauli deT. spectabilis. La différence principale entre les hydranthes et les hydrocauli réside dans la distribution de certaines taches non-identifiées qui apparurent dans les chromatogrammes developpés avec la ninhydrine et les réactifs pour les groupes des imidazoles, guanidines, ou sulfhydriles.

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Part of a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Florida State University. Aided by a National Science Foundation Predoctoral Fellowship and a National Science Foundation Grant to Dr. C. B.Metz, Contribution number 122 from the Oceanographic Institute, Florida State University.