No abstract

Aim The purpose of this study was to reconstruct early nineteenth-century vegetation and fire regimes to examine the role of fire, topography, and substrate interactions in shaping landscape and regional vegetation patterns. LocationOur study area was the Current River watershed of the Ozark Highlands in south-central Missouri, USA. MethodsWe combined analysis of early nineteenth-century Public Land Survey (PLS) notes and dendrochronology-based fire histories to reconstruct vegetation and disturbance regimes of pine-oak (Pinus-Quercus) woodlands.Three methods were used to display and analyse PLS data within a Geographic Information System (GIS): (1) simple point distributions for each tree species; (2) section line descriptions of each tree species and other coded features (e.g. 'prairie'); and (3) spatial interpolation of the point-tree data.Vegetation patterns were then related to geological parent material, topography, and mean fire-return intervals from 23 sites using correlation and Canonical Correspondence Analysis (CCA). ResultsThe most striking patterns in the early 1800 s were extensive stands of shortleaf pine (Pinus echinata Mill.) and oak-dominated 'barrens' (savanna) in the frequently burned areas south-west of the Current River, and more mesophytic, fire-sensitive species (red oaks (Quercus rubra L., Q. coccinea Muenchh.), maples (Acer rubrum L., Acer saccharum Marsh), eastern red cedar (Juniperus virginiana L.) in a fire shadow north-east of the river. Several kilometre-wide ecotones of pine-mixed hardwood encompassed the major pineries and barrens.Fire-return intervals and relative dominance of several tree species were strongly correlated at both fine (3-64 km 2 ) and coarse (> 100 km 2 ) spatial scales. At fine scales, relative dominance of shortleaf pine increased with increasing fire frequency during 1701-1820. Relative dominance of black oak (Q. velutina Lam.), and to a lesser extent post oak (Q. stellata Wang.), decreased with increasing fire frequency. Shortleaf pine and these xerophytic oak species occurred on similar bedrock types but were strongly differentiated by fire regimes. Main conclusions Fires exerted strong constraints on vegetation composition and patterns.Historical patterns of Native American occupancy in the region are consistent with the reconstructed vegetation and fire histories and suggest that anthropogenic fire regimes played an overriding role in the development of Ozark vegetation in the 1800s.

No abstract

No abstract

No abstract

A stable complex between pentaammineruthenium(III) and histidine-33 in horse heart ferricytochrome c is formed in the reaction between aquopentaammineruthenium(II) and the protein at pH 7. HPLC of the tryptic hydrolysate of the modified protein was employed to identify the pentaammineruthenium binding site. Spectroscopic measurements show that the integrity of the native structure in the vicinity of the heme c group is maintained in the ruthenium-modified protein. Matthews has shown (2-5) that Ru(NH3)5H202+ is a good reagent for modification of histidine residues in proteins, and we have found that the reaction of Ru(NH3)5H202' with horse heart cytochrome c, followed by oxidation, produces several stable Ru(NH3)53+-ferricytochrome c derivatives. Characterization of one of these derivatives, Ru(NH3)5(His-33)3+-ferricytochrome c, is reported here. Five distinct peaks (A-E) from four separate Ru(NH3)5Cl2+/ Zn (amalgam) preparations were pooled and purified as follows: Peak A (ca. 32 mg ofcytochrome c) was rechromatographed on a column (2.3 x 32 cm) ofCM52 with 85 mM sodium phosphate buffer (pH 7.0); peak B (ca. 42 mg) was rechromatographed on CM52 with 85 mM sodium phosphate buffer (column bed, 2.3 X 26 cm); peak C (ca. 48 mg) also was eluted from a CM52 column (2.3 x 19 cm) with 85 mM sodium phosphate buffer; peaks D (ca. 24 mg) and E (ca. 43 mg) were rechromatographed on CM52 with 100 mM sodium phosphate buffer (pH 7.0). Column beds were 2.3 x 19 cm (peak D) and 2.3 X 17 cm (peak E). In all cases, a flow rate of 30 ml/hr was maintained and 5-ml fractions were collected. The absorbance ofevery other fraction was read at 410 nm. MATERIALS AND METHODSThe fractions corresponding to each ofthe major species that eluted upon rechromatography were pooled (A'-E'). All experiments reported here are for E' (concentrated solutions that were to be used within a few days were kept at 4°C; other samples were shell-frozen in liquid nitrogen and stored at -100C) or its analogue in the Rutgers' preparation. E' was analyzed for Ru by flame atomic absorption. The Ru/heme c ratio was found to be 1:1 (± 10%).Protein Modification (at Rutgers). A 20-ml solution of Ru(NH3)5H202+ (-0 7052The publication costs ofthis article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.

No abstract

grams of shredded coconut. The mixture was extracted with 3 X 150 ml. of water. The extract was dried by azeotropic distillation with pyridine and acetylated as described above. Gas