Isolation and characterization of pentadin, the sweet principle of Pentadiplandra brazzeana Baillon

An aqaeous extract from the pulp of the plant Pentadiplandra brazzeana Baillon (Pentadiplandraceae) yielded a strong sweet-tasting material. This sweet principle was isolated by water extraction, ultrafiltration and gel filtration. The conclusion that this substance must be of a proteinaceous nature was based on amino acid analysis, characteristic UV-absorption spectrum and positive colour reaction with Coomassie brilliant blue. The mol. wt of the subunit of the sweet protein was estimated to be ˜ 12 000 daltons. The sweetness intensity of the whole protein was ˜ 500 times that of sucrose on a weight basis. The taste response in a Rhesus monkey to a 0.1 % solution was comparable to the response to a 0.02 % monellin solution. We propose the name ‘pentadin' for this sweet-tasting protein and present a few comments about the possible origin of such sugar mimic

Self-Consistency Requirement in High-Energy Nuclear Scattering

Practically all serious calculations of exclusive particle production in ultra-relativistic nuclear or hadronic interactions are performed in the framework of Gribov-Regge theory or the eikonalized parton model scheme. It is the purpose of this paper to point out serious inconsistencies in the above-mentioned approaches. We will demonstrate that requiring theoretical self-consistency reduces the freedom in modeling high energy nuclear scattering enormously. We will introduce a fully self-consistent formulation of the multiple-scattering scheme in the framework of a Gribov-Regge type effective theory. In addition, we develop new computational techniques which allow for the first time a satisfactory solution of the problem in the sense that calculation s of observable quantities can be done strictly within a self-consistent formalism.Comment: 7 pages, 6 figure

"It's not about the parents": A Content Analysis of Representations of Sperm Donor Conception in Young Adult Literature

This study aims to examine how donor-conceived youth are portrayed in novels marketed toward adolescents. It categorizes how the developmental needs of donor-conceived youth are uniquely met, as well as the developmental needs of all teens, in these books. This is done through a qualitative content analysis of young adult novels that feature a character that was conceived via sperm donor. In conducing this research, the study hopes to help librarians make collection decisions regarding young adult novels that feature donor-conceived characters, as well as help donor-conceived youth identify books in which they can see themselves in the pages.Master of Science in Library Scienc

Isolation and characterization of pentadin, the sweet principle of Pentadiplandra brazzeana Baillon

An aqaeous extract from the pulp of the plant Pentadiplandra brazzeana Baillon (Pentadiplandraceae) yielded a strong sweet-tasting material. This sweet principle was isolated by water extraction, ultrafiltration and gel filtration. The conclusion that this substance must be of a proteinaceous nature was based on amino acid analysis, characteristic UV-absorption spectrum and positive colour reaction with Coomassie brilliant blue. The mol. wt of the subunit of the sweet protein was estimated to be ˜ 12 000 daltons. The sweetness intensity of the whole protein was ˜ 500 times that of sucrose on a weight basis. The taste response in a Rhesus monkey to a 0.1 % solution was comparable to the response to a 0.02 % monellin solution. We propose the name ‘pentadin' for this sweet-tasting protein and present a few comments about the possible origin of such sugar mimic

Dynamics of the introduced tree Litsea glutinosa (Lauraceae) in Mayotte Island: is it an invasive species?

Litsea glutinosa (Lour.) C.B. Rob., l'avocat marron, est un arbre dioïque d'Australasie qui a été introduit à Mayotte et multiplié à l'époque de la canne à sucre (1841-1880). Disséminée efficacement par les lémuriens (Eulemur fulvus) et par de nombreux oiseaux, cette Lauraceae s'est étendue sur toute la zone humide et est présente dans les dernières forêts « naturelles » fragmentées de l'île. Cet arbre de 10 à 15 mètres de hauteur se concentre actuellement dans les deux-tiers nord plus arrosés (pluviosité > 1 500 mm/an) de Mayotte. Ce travail analyse la dynamique entre 1996 et 2002 des populations de Litsea glutinosa établies dans les reliquats de forêt mésophile et ombrophile et la part de la multiplication végétative dans certaines populations. L. glutinosa prolifère dans les réserves forestières et particulièrement en forêt semi-sèche en fonction de la structure forestière plus ou moins ouverte. Par son tempérament héliophile, cette espèce nécessite une perturbation pour croître et se fixer en forêt. Sa persistance et son caractère envahissant sont dus en partie à sa possibilité de multiplication végétative à l'origine de plus de la moitié des fûts. principalement par drageonnage. Cette espèce constitue un risque d'appauvrissement spécifique dans les zones « naturelles » sans pour autant être considérée par les mahorais comme une peste en raison de sa fréquente utilisation en particulier comme plante fourragère.Litsea glutinosa (Lour.) C.B. Rob, the Indian laurel, is a dioecious tree from Australasia which has been introduced on Mayotte and has proliferated during the era of sugar cane plantations (1841-1880). Efficiently dispersed by the Brown Lemur (Eulemur fulvus) and by numerous birds, this Lauraceae species now spreads into the humid area and it is present in the last remaining « natural » fragmented forests of the island. This tree, ranging from 10 to 15 meters in height, is mostly found on the wetter (rainfall > 1 500 mm/year) northern part of the island. This study analyses the population dynamics of Listea glutinosa between 1996 and 2002 in the remains of the mesophilous and ombrophilous forests, as well as the importance of vegetative reproduction in certain populations. L. glutinosa proliferates in protected forests, particularly in semi-dry forests where it can take advantage of the more open forest structure. Because of its light-demanding temperament, L. glutinosa needs an opening in the forest canopy to settle down and grow. The tree’s invading nature, however, is due partially to its capability to reproduce vegetatively; over half of the stems are produced by vegetative reproduction, mostly root-suckering. This species could lead to a specific loss of biodiversity in « natural » areas, but is not considered as a pest by local inhabitants, because of its frequent utilization, especially as fodder

Les mammifères frugivores arboricoles nocturnes d'une forêt guyanaise : inter-relations plantes-animaux

The relationships between a community of nine nocturnal frugivorous mammal species and the plants on which they feed were studied during 14 consecutive months in a secondary forest near Cayenne, French Guiana. Two major trophic groups can be defined : 1. - The seed eaters, which open unripe fruits to eat their seeds. All are rodents : Coendou prehensilis (average adult weight 4 000 g), Echimys armatus (400 g) and Oryzomys concolor (35 g). 2. - The pulp eaters, which specialize in ripe fruits. They eat the pulp and swallow most of the seeds which are disseminated with their feces. Five of them are marsupials : Didelphis marsupialis (1 000 g), Philander opossum (400 g), Caluromys philander (300 g), Marmosa cinerea (80 g) and Marmosa murina (45 g). The sixth species is a Procyonid Carnivore : Potos flavus (3 000 g). These differing types of feeding strategies are discussed in relation to the morphology of the teeth and digestive tract of the species. Species with a similar diet and comparable body size generally live in different forest layers. The population density and biomass of these nocturnal frugivorous mammals were estimated on the basis of direct counts along forest trails at night, trapping results and radio-tracking. Out of the 127 plant species listed, 26 play a major role as a food source for the mammals studied. The trunk diameter (DBH) of the 13 most common species was measured, and the distribution of these trees mapped in the 8.5 ha study area. These 13 tree species account for approximately half of the total basal area, which is considered here as an index of standing crop biomass. The same 13 species account for 25 % of the total number of individual trees. Fruit production was measured during 13 months by weighing all fallen fruits along 1 200 m of trails. Fruit production and consumption of the same species were also estimated by the use of fruit collectors located under fruiting trees. Special attention was given to the phenological cycles of trees. Three types of fruiting cycles could thus be related to three different foraging strategies of the sympatric frugivorous mammals : 1. - Species with a low fruit production spread over an extended time period. Only a few fruit ripen at the same time, but fruiting takes place almost all year long. Such trees are early - or late - pionneer species ; their fruits have tiny seeds which are mainly eaten by small vertebrates which scatter them more or less homogeneously. 2. - Species with synchronous, but irregular cycles of fruit production. Such trees have rather large seeds which are very attractive to seed-eating rodents. These animals even destroy part of the fruit crop before ripening. The massive, irregular, and unpredictable fruiting cycles of these species may reduce seed predation by rodents . The few trees belonging to this category which do not bear fruit synchronously with their conspecifics may have their crop totally destroyed by rodents. 3. - Species with synchronous and regular cycles of fruit production. Such trees have rather large seeds, which are ingested by large frugivorous vertebrates and spread through their feces. Chemical or physical deterrents are generally present in such fruits before ripening. The tree species belonging to this category have successive and partly overlapping periods of fruit production. In this way, food is made available for pulp-eaters during most of the year. This pattern of fructification is presumably the end-result of a long lasting mutual interaction between plants and seed-scattering vertebrales. Frugivorous mammals apparently need two different kinds of fruit in their diet, sorne rich in sugar and others rich in fat. Trees producing these two categories of fruit produce their crop successively, so that the necess ary nutrients are made available throughout the year. A definite decrease in fruit production takes place in our study are ajust before the beginning of the dry season. The marsupial pulp-eaters have adapted to this temporary food shortage by storing fat during the season of plenty. However, their production of young is strongly affected by this seasonal food shortage, as shawn by an increased mortality rate of pouch young

A Unified Treatment of High Energy Interactions

It is well known that high energy interactions as different as electron-positron annihilation, deep inelastic lepton-nucleon scattering, proton-proton interactions, and nucleus-nucleus collisions have many features in common. Based upon this observation, we construct a model for all these interactions, which relies on the fundamental hypothesis that the behavior of high energy interactions is universal.Comment: 4 pages, LaTeX created with LyX, 8 figures, more figures at http://www-subatech.in2p3.fr/~theo/nexus/example