Origin of the high-frequency resonances in 1H NMR spectra of muscle tissue: an in vitro slow magic-angle spinning study

High-resolution slow magic-angle spinning (150 Hz) 1H PASS NMR spectroscopy is performed on intact excised rat m. tibialis anterior. Untreated muscles and muscles in vitro incubated in Krebs-Ringers buffer based on deuterium oxide are investigated. In the high-frequency region of the 1H NMR spectra, resonances from H4 (approximately 7.1-7.2 ppm) and H2 (approximately 8.2-8.5 ppm) in histidine are observed. In addition, a resonance appears at 6.7 ppm for the untreated muscles. However, this resonance is absent in muscles following incubation in deuterium oxide. On the basis of its behavior in deuterium oxide combined with supplementary measurements for creatine solutions, the 6.7 ppm resonance is ascribed to the amino protons in creatine. Moreover, the present study demonstrates that the observation of the 6.7 ppm resonance depends on pH, which explains earlier reports stating its occasional appearance. Finally, measurements on solutions of ATP/AMP and histidine indicate that both ATP/AMP and histidine contribute to the resonances at approximately 8.2-8.5 ppm in the 1H NMR spectra of muscle tissue.     

Characteristics of inbred progenies from morphologically unstable Sorghum plants

Progenies from 68 self-pollinated panicles of 10 somatically unstable sorghum-sudangrass hybrid sectors were grown. Data are presented for 25 progenies from three representative unstable plants. Highly uniform progenies were obtained from most panicles. Results indicate chromosome assortment was not always at random. Major distinctions between panicle progenies suggested that: (a) sorghum-like and sudangrass-like genomes functioned as units; (b) gene transfer and association were non-random further indicating that somatic chromosome substitution or somatic translocations, or other gross changes, may have occurred; and (c) other deviating behaviors implied genetic segregation.Results of cooperative work of the Crops Research Division, Agricultural Research Service, U. S. Department of Agriculture, and the Wisconsin Agricultural Experiment Station, Madison, Wisconsin 53706 U.S.A.     

The effect of weed cutting on Luronium natans

• 1. Luronium natans is a rare macrophyte that seems to be disappearing from lakes and rivers throughout its distribution area. In Denmark L. natans is most often found in man‐made canals and ditches, and its presence seems to be favoured by regular physical disturbance. Hence, management by cutting presents a possible method of preserving the few remaining populations of L. natans in Denmark and throughout its distribution area.
• 2. The objective of this study was to elucidate the effect of different weed cutting frequencies on L. natans in order to propose recommendations for management with weed cutting for future conservation of L. natans.
• 3. Three reaches of a river with L. natans were subjected to the following weed cutting frequencies: no cutting, twice per year, and four times per year, and the cover of L. natans and of other plants was monitored from June 2003 to October 2004.
• 4. L. natans developed highest cover when subjected to weed cutting four times per year, but the frequency of flowering was then very low, resulting in a reduction in sexual reproduction, which could lead to a lower genetic diversity and possibly fatal effects in the long term. At a cutting frequency of twice per year L. natans was able to maintain healthy and sexually reproducing populations.
• 5. Future management in canals should consist of weed cutting once or twice per year to prevent a population from being outcompeted by other species and to secure production of flowers and seeds. Alternatively, high frequencies of weed cutting could be performed in order to suppress competitive species, but should then be accompanied by a weed cutting‐free zone where flowering can occur.

Copyright © 2006 John Wiley & Sons, Ltd.     

A method for determination of the degree of gelatinization of starch

Summary An exactly weighed quantity of material to be analysed, corresponding to about 0.4 g starch, is hydrolized with α- and β-amylase as a catalyst. A corresponding quantity of the materil is boiled, cooled and then hydrolized with α- and β-amylase. The amounts of reducing carbohydrates produced, mainly maltose, are determined, and the relation between them is equivalent to the relation between the quantity of total starch and the quantity of gelatinized starch. A blank determination is done to give a correction for the reducing power of the enzymes and the raw material.

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Zusammenfassung Bei der Nerz-Fütterung mit Kartoffelmehl ist es für dessen Ausnützbarkeit sehr wichtig, dass die St?rke geliert ist. Die hier beschiebene analytische Methode erm?glicht eine genaue Bestimmung des Geliergrades. Das Prinzip ist, dass nur gelierte St?rke duch die Enzyme α- und β-Amylase hydrolysiert werden kann; der Reaktionsverlauf wird in Tabelle 2 gezeigt. Eine genau abgewogene Menge des zu analysierenden Materials, ungef?hr 0.4 g St?rke entsprechend, wird mit α- und β-Amylase als Katalysator hydrolysiert. Eine entsprechende Menge des Materials wird gekocht, gekühlt und dann mit α- et β-Amylase hydrolysiert. Die Menge der erzeugten reduzierenden Kohlehydrate, haupts?chlich Maltose, wird bestimmt, und das Verh?ltnis zwischen ihnen ist gleich dem Verh?ltnis zwischen der gesamten St?rkemenge und der Menge der gelierten St?rke. Eine Blindbestimmung wird vorgenommen, um eine Korrektur für die Reduzierf?higkeit der Enzyme und des Rohmaterials zu erm?glichen. Die Standard-Abweichungen einer Anzahl Analysen von Material mit bekanntem Geliergrad sind in Tabelle 3 angegeben.

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Résumé Quand la pomme de terre en poudre est utilisée dans l’alimentation des Martres il est très important que l’amidon soit gélatinisé. La méthode analytique ici décrite rend possible la détermination exacte du degré de gélatinisation. Le principe est que seul l’amidon gélatinisé peut être hydrolisé par les enzymes α- et β-amylase, dans le Tableau 2. On hydrolyse avec α- et β-amylase comme catalyseur une quantité de matière à analyser exactement pesée correspondant à environ 0,4 g d’amidon. Une quantité correspondante de matière est bouillie puis refroidie et ensuite hydrolysée avec α- et β-amylase. On détermine les quantités des hydrates de carbone réducteurs produits, principalement le maltose, le rapport de celles-ci est équivalent au rapport entre la quantité totale d’amidon et la quantité d’amidon gélatinité. On fait une détermination à blane pour apporter une correction en raison du pouvoir réducteur des enzymes et du matériel cru. Le Tableau 3 donne les déviations standards d’un certain nombre d’analyses de matière avec un degré connu de gélatinisation.

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Report no. 47 from the Research Institute of Commercial and Industrial Plants, Kolding, Denmark.     

In vitro shoot regeneration ofSolanum tuberosum cultivars: interactions of medium composition and leaf, leaflet, and explant position

Summary Shoot regeneration was investigated on explants from different leaves and leaflets of three potato cultivars Posmo, Folva and Oleva. Explants were excised from glasshouse grown plants and grown for 6 days on callus induction medium with indole-3-acetic acid or 2,4-dichlorophenoxyacetic acid. Explants were then transferred to auxin free shoot regeneration medium with gibberellic acid and 6-benzyladenine or zeatin. By using the optimum combinations and concentrations of plant growth regulators and by excision of explants from particular regions of proximal leaflets from newly unfolded leaves, shoot regeneration frequencies of 97.0% were obtained for cv. Posmo and 32.1% for cv. Folva. Shoot regeneration frequency of cv. Oleva was very low and could not be improved by the different treatments.     

Erwinia species in the lenticels of certified seed potatoes

Twelve-tuber samples were collected from 39 certified seed stocks grown in 4 states and a Canadian province. One-half of each sample was immersed in water and the other half exposed to a CO₂-N atmosphere at 25C to induce soft rot development at the lenticels. Pectolytic bacteria were isolated from 24 seed stocks which represented each producing area. The pathogenicity and biochemical reactions of 20 isolates were those ofErwinia carotovora var.atroseptica, except for one isolate which grew at 37C. Four isolates did not cause black leg but only three reacted biochemically likeE. carotovora var.carotovora. The results confirm reports that theErwinia spp. are tuber borne and that anaerobic conditions stimulate infection of naturally inoculated lenticels.     

Phytophthora erythroseptica in Peru: Its identification and pathogenesis

EightPhytophthora isolates cultured from diseased potato plants and tubers in Peru were identified asPhytophthora erythroseptica Pethyb. var.erythroseptica. This pathogen was not previously reported from South America. The isolates were pathogenic to potato plants but they differed in virulence. Injuring roots prior to inoculation enhanced infection and disease development but all isolates infected noninjured roots. Continuous high soil moisture during incubation favored disease development. Under these conditions, disease developed at soil temperatures from 10 C to 30 C, but most rapidly at 25 C and 30 C. Plants grown 60 days before inoculation developed symptoms earlier and more rapidly than plants grown 15-, 30-, and 45 days. Four concentrations of mycelial-suspension inocula did not alter disease development, but zoospore inoculum induced symptoms and plant death more rapidly than mycelial suspensions at 25 C.