Protein intake regulation in the weanling rat: Effects of additions of lysine,arginine and ammonia on the selection of gluten and energy

The effects of adding lysine, arginine and ammonia to gluten on the self-selection of protein and energy by the weanling rat simultaneously offered a choice of two diets differing only in gluten concentration (15 and 55%) were tested. Previous studies have shown that while lysine (6 g/100 g) additions to gluten decreased the amount of gluten selected by the rat from 40 to 20 g per 100 g of food eaten, selection was not related to the nutritional quality of the gluten. When graded levels of arginine (1.8, 3.6 or 7.2 g/100 g) were added to the gluten with or without lysine (0 or 6 g/100 g) the dietary protein selection was unaffected. The addition of ammonia (1.4 g/100 g as NH₄Cl) to gluten had initially the same effect as lysine (6 g/100 g) but with time protein intake returned to control levels. This effect of ammonia was unaltered by arginine additions. It is concluded that the mechanisms which lead to decreases in gluten selection caused by lysine or ammonia are not similar, and that the effects of lysine on gluten selection are not caused by an increased arginine requirement for urea cycle activity.     

Constituted through Conflict: Images of Community (and Nation) in Bulgarian Rural Ritual

Following the 20th anniversary of Benedict Anderson's Imagined Communities, this article extrapolates how attention to actual notions of community might redirect his important intervention. It suggests that locally and culturally specific ideas about collectivity shape the experience and expectations of national-level projections. To demonstrate this outcome the analysis focuses on Bulgarian mumming—spectacular winter rituals in which threatening masked figures transverse villages to banish evil and bring good fortune. While these rituals clearly reinforce social solidarity, they represent a local notion of community in which conflict, both intra-and interethnic, is elemental and constitutive. This image of community does not demand consensus or homogeneity when imagined on a national scale. Such variations in community notions may help explain the diversity of national experiences increasingly documented by ethnographers.     

Chloroplast and cytoplasmic enzymes 1, 2, 3. Subunit structure of pea leaf aldolases.

The pea leaf chloroplastic and cytoplasmic forms of aldolase are very similar in structure. The subunit molecular weights determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate are approximately 37.000. Both aldolases appear to terminate in the same sequence, SerAlaTyrCOOH, and the amino-terminal sequence H₂NGlySerTyrAla was obtained for each. The previously reported differences in kinetic properties and in isoelectric points of the two pea leaf enzymes probably are the consequence of minor differences in amino acid composition or conformation.     

Overexpression of miRNA 4451 is Associated With a Poor Survival of Patients With Hypopharyngeal Cancer After Surgery With Postoperative Radiotherapy

Hypopharyngeal cancer (HC) is the most common subset of head and neck cancers. These tumors often have an aggressive clinical outcome characterized by local invasion and regional nodal metastasis. Upregulated miRNAs might be useful as biomarkers for prognosis and molecular targets for these tumors. We determined tumor expression of candidate miRNAs using microarray in 8 HC patients and validated in 372 HC patients. We also used paired tumorous and mucosal tissue to verify the miRNA expression. Log-rank test and Cox model were used to evaluate the survival; and Harrell's C-index was used to compare concordance of Cox models. Our results indicated 7 miRNAs aberrantly expressed in HC. Three of these candidate miRNAs (miRNA-4415, miRNA-200a, and miRNA-30b) were selected for further qRT-PCR validation and all of them were frequently found upregulated in HC tumors; with miR-4451 being the most differentially expressed. Moreover, high expression of miR-4451 was positively correlated with advanced tumor stage and increased mortality risk (HR: 1.6, 95% CI: 1.2–2.3; adjusted HR: 1.5, adjusted 95% CI: 1.1–2.1). Finally, significantly higher expression of miR-4451 in tumors compared to in fresh adjacent normal tissues indicates an oncogenic role of miR-4451 in this tumor. Upregulated miR-4451 in HC samples were frequently found and is significantly associated with advanced stage and poor survival of HC, which may indicate an association of this miRNA with the carcinogenesis process in this tumor site; and they could serve as a prognostic biomarker as well as help develop potential new targets for therapy.     

G. Ledyard Stebbins, Jr. and the evolutionary synthesis (1924-1950)

This is an historical paper examining the scientific background of George Ledyard Stebbins, Jr. (b. 1906), one of the foremost botanists of this century and one of the architects of the evolutionary synthesis, the intellectual event that brought together genetics and selection theory in the interval between 1920 and 1950. It considers his scientific influence and research, beginning with his Harvard education in 1924 and ending in 1950 with the publication of his book Variation and Evolution in Plants. The paper also more broadly assesses the contributions of other botanists to the evolutionary synthesis, including discussion of the work of Edgar Anderson (1897-1967) and others. It also traces the larger historical patterns of American botany, which saw a shift from East Coast botany as exemplified by Harvard botany, to West Coast botany, as exemplified by California botany.     

Vegetation,environmental characteristics and ideas on the maintenance of alvars on the Bruce Peninsula,Canada

Abstract. Despite international recognition that alvar habitats are important reservoirs of biodiversity, they remain little studied in North America. In this paper, the results are reported on an investigation of alvars in the central portion of their known distribution on this continent. 210 plots were distributed among seven sites and were quantitatively sampled for vascular plants, lichens, bryophytes and a suite of environmental variables. Detrended and Canonical Correspondence Analyses and other methods were used to investigate differences among alvars, within alvars and between alvars and adjacent forested habitats. The plant communities and environmental conditions were highly similar among sites in the study region, yet very different from surrounding habitats. There were abrupt changes in vegetation and environmental conditions from alvar to forest, without the presence of transition zones in the vegetation or environmental gradients as the forest was approached. The environmental factors associated with the change from alvar to forest and with variation within alvar habitat were examined. Some alvars in the study were found to contain stunted, slow-growing trees reaching ages of 524 yr. These same sites appear to have remained unburned for several centuries, while other sites likely burned 90 yr ago. The plant communities were very similar between the alvars that lacked a major, biomass-removing disturbance in centuries and alvars that had experienced catastrophic fire relatively recently. Maintenance of the plant communities and open nature of alvars appears site-specific rather than habitat specific.     

Phytogeographical and community similarities of alpine tundras of Changbaishan Summit,China, and Indian Peaks,USA

Abstract. We compared the diversity, phytogeography, and plant communities in two mid-latitude alpine tundras with comparable aerial and elevational extents: Changbaishan Summit in eastern Asia and Indian Peaks in western North America. Despite wide separation, the two areas shared 72 species. In all, 43% of the species on Changbaishan Summit are also distributed in the alpine zones of western North America, while 22% of the species on Indian Peaks are also distributed in the alpine zones of eastern Asia. Almost all the shared species also occur in the Beringian region. Phytogeographical profiles of species and genera showed that 69% of species and over 90% of genera in both alpine tundras belong to the three phytogeographical categories: cosmopolitan, circumpolar, and Asian-North American. We attributed the current floristic relationship between these widely separated areas to the periodic past land connection between the two continents during the Tertiary and Pleistocene. Indian Peaks has a closer floristic relationship with the Arctic tundra than does Changbaishan Summit. Indian Peaks also has 45% higher species richness and lower vegetation cover than Changbaishan Summit. Plant communities from the two areas were completely separated in the two-way indicator species analysis and non-metric multidimensional scaling on floristic data at both species and generic levels, whereas ordination of communities by soil data produced a greater overlap. The plant communities on Changbaishan Summit in general have lower alpha diversity, higher beta diversity (lower between-community floristic similarity), and more rare species than does Indian Peaks. Mosaic diversity does not differ in the two alpine tundras, although the analysis suggests that Changbaishan Summit communities are more widely spaced on gradients than the Indian Peaks communities.     

Records of the gadoid fish <Emphasis Type="Italic">Arctogadus glacialis</Emphasis> (Peters, 1874) in the European Arctic

The Arctogadus glacialis is endemic to the Arctic Ocean and its apparently disjunct circumpolar distribution range from the Siberian coast through the Chukchi Sea and the Canadian Arctic to the shelf off NE Greenland. Records of A. glacialis are scarce in the European Arctic and here we present all available and reliable records of the species in the area. Altogether, 296 specimens of A. glacialis are reported from 53 positions in the European Arctic during the period 1976–2008. The specimens were registered off Iceland and the Jan Mayen Island, northwest and northeast of Svalbard, northeast in the Barents Sea, and south and east off Franz Josef Land. The additional records show that A. glacialis display a circumpolar and more continuous distribution than described before. In the European Arctic, A. glacialis has been caught at 155–741 m depth with the highest abundance at 300–400 m. We therefore suggest that A. glacialis is more associated to the continental shelves surrounding the Arctic Ocean than previously thought. The length–weight relation of A. glacialis is similar across the European Arctic.