Phylogenetic and phenotypic structure among Banksia communities in south‐western Australia

Aim Phylogenetic and phenotypic patterns among coexisting banksias (Banksia, Proteaceae) in the infertile, fire‐prone landscapes of south‐western Australia were examined for evidence of community structuring. It was expected that closely related species would be spatially clustered (underdispersed) as a consequence of widespread recent speciation, strong edaphic fidelity and low dispersability. We also expected that edaphic filtering would result in phenotypic clustering of traits related to habitat specialization and that competitive exclusion among closely related species with similar regeneration biology and growth form would result in phenotypic overdispersion of these latter traits. Location Southwest Australian Floristic Region (SWAFR). Methods Based on published data for coexistence (richness and frequency) of Banksia species at 40 sites in the three floristic provinces, phylogenetic, soil type and morphological mean pairwise distance and mean nearest taxon distance were calculated for each site and compared with null communities. Patterns of co‐occurrence were examined at the local and subregional (provincial) scales. Results Of the 40 sites assessed, 21–30 displayed phylogenetic clustering of Banksia species (5–11 significantly) such that, overall, co‐occurring taxa were more closely related than expected by chance. Banksias in the Transitional Rainfall and Southeast Coastal Provinces were more likely to display phylogenetic clustering than in the High Rainfall Province. A significant trend for phylogenetic clustering associated with edaphic specialization (27–30 sites) was observed, as well as a significant trend for phenotypic overdispersion associated with growth form (25–28 sites). Results for regeneration biology depended on the metric used. Main conclusions We demonstrate spatial clustering of closely related banksias at the local and provincial scales, consistent with their restricted distribution (recent widespread speciation, patchy habitat availability and limited dispersability) in this geologically old and stable region. The clustering of closely related species may also be a consequence of habitat filtering linked to edaphic fidelity in the SWAFR flora, while overdispersion in growth form suggests that functional divergence favours coexistence in Banksia communities.     

Ruptured fission yeast walls

Distributions of rupture sites of fission yeast cells ruptured by glass beads have been related to a new morphometric analysis. As shown previously (Johnson et al.,Cell Biophysics, 1995), ruptures were not randomly distributed nor was their distribution dictated by geometry, rather, ruptures at the extensile end were related to cell length just as the rate of extension is related to cell length. The extension patterns of early log, mid-log, late log, and stationary phase cells from suspension cultures were found to approximate the linear growth patterns of Kubitschek and Clay (1986). The median length of cells was found to decline through the log phase in an unbalanced manner.     

Plant phosphoglucose isomerase genes lack introns and are expressed in Escherichia coli

Nuclear genes that appear to encode both cytosolic and plastid isozymes of phosphoglucose isomerase (PGI), an essential glycolytic enzyme, have been isolated from three diploid species of the annual wild flower genus Clarkia (Onagraceae). The genes do not contain introns and are expressed to varying degrees in Escherichia coli when cloned in either Charon 35 phage or pUC plasmid vectors. The PGI proteins synthesized in E. coli form dimers, are catalytically active, and their electrophoretic mobilities are similar to those of appropriate Clarkia PGIs. The nucleotide sequence of a gene encoding a plastid isozyme of C. unguiculata is described.     

The effects of disturbance on forest butterflies using two methods of sampling in Trinidad

The butterfly assemblages of pairs of forest habitats, differing in disturbance level, within the Victoria Mayaro reserve of South-East Trinidad, are described using walk-and-count transects and canopy and understorey fruit traps. The concurrent use of these two butterfly censusing techniques, revealed major but conflicting differences in species accumulation rates under different disturbance conditions. The disturbed evergreen habitat had the significantly highest accumulation rate from walk-and-count data but the significantly lowest from fruit trap data. This reflects the specificity of much of the fruit-feeding guild for closed canopy forest. Disturbed habitats were found to lack a distinct canopy fauna. These results are discussed in light of the intermediate disturbance hypothesis. Within a region of forest, butterflies were found to be more characteristic of a disturbance level than of a particular forest type, lending weight to the belief that butterfly faunas can be used as bioindicators of forest disturbance. Several restricted geographic range species were not adversely affected by forest disturbance, at these levels of disturbance. The butterfly censuses in this study suggest that the optimal strategy for safeguarding butterfly species richness under natural forest management regimes would be to maintain a mosaic of habitats that included areas of undisturbed primary forest and a network of other forest patches, that varied in management regime and level of disturbance.     

Arts integration in rural Minnesota: A collaborative arts integration framework

In this article, we demonstrate that arts integration holds unique promise and benefits for helping rural teachers to provide more equitable arts opportunities for their students. These benefits include: professional network development in the service of both curricular development for arts integration and connecting teachers who often work in isolation; additional funding to allow for collaborative planning; and introduction to arts experiences and cultural resources for use in arts-integrated unit planning and implementation. We describe the Perpich Arts Integration Project—an innovative, state-funded program centered on a Collaborative Arts Integration Framework in three rural regions of Minnesota. Then, through data collected via a three-year longitudinal program documentation and evaluation, we describe several themes that we have identified about the implementation of arts integration in rural schools. Finally, we will describe a series of considerations and implications for rural schools seeking to implement such a program in the future.     

Studies of oxidative phosphorylation in Saccharomyces cerevisiae and Saccharomyces carlsbergensis

Mitochondria isolated from cultures of Saccharomyces cerevisiae and Saccharomyces carlsbergensis, which were harvested late in the stationary phase of growth at a time when full development of the electron transport and associated phosphorylation systems had occurred, carried out oxidative phosphorylation with P:O ratios of approximately 3 and 2 when pyruvate-malate and succinate, respectively, were used as substrates.     

Isopycnic-zonal centrifugation of plasma membrane,sarcoplasmic reticular fragments,lysosomes, and cytoplasmic proteins from phasic skeletal muscle

Homogenates of the posterior latissimus dorsi muscle, a phasic muscle, were fractionated by a one-step zonal centrifugation technique into four major organelle populations and cytoplasmic constituents. These were: (1) Plasma membrane fragments with a modal equilibrium density of 1.10 and containing 5′-nucleotidase, alkaline phosphodiesterase, $\text{p-}\text{nitrophenylphosphatase}$ and acid phosphatase (β-glycerophosphate was used as the substrate). (2) Sarcoplasmic reticular fragments which could be further subdivided into calcium transport vesicles, with a modal equilibrium density of 1.16, that exhibited calcium uptake; K⁺-ATPase; leucyl-β-naphthylamidase; acid phosphodiesterase; acid phosphatase (using cytidine monophosphate as the substrate); and sarcoplasmic reticular lysosomes, with a modal equilibrium density of 1.18, possessing dipeptidyl-aminopeptidase II, cathepsin D, α-glucosidase, $\text{N-}\text{acetyl}\text{-β-}\text{glucosaminidase}$, and NADH oxidase activity. (3) Mitochondria with a modal equilibrium density of 1.21. (4) Catalase-containing vesicles with a modal equilibrium density of 1.22; and cytoplasmic constituents (modal density of 1.25) with phosphorylase, pyruvate kinase, myosin-ATPase, aldolase, and protein and RNA content. The purity of these organelles was equal to or better than previous efforts, with a 30-fold purification achieved for 5′-nucleotidase and alkaline phosphodiesterase. These results lend support to the hypothesis that the sarcoplasmic reticulum of phasic muscle, in addition to its specialized role in excitation-contraction coupling, represents a multifunctional membrane system, and that, similar to the smooth endoplasmic reticulum of other cells, it includes some membrane-bound lysosomal enzymes and NADH oxidase.     

Effect of Gossypol on Some Oxidative Respiratory Enzymes

Gossypol was examined in relation to its effect on certain enzymes and enzyme complexes associated with the tricarboxylic acid cycle and the electron transport system. Succinic dehydrogenase and cytochrome oxidase activity from sweet potato was completely inhibited by gossypol at 7.5 x 10(-3)m and 2.0 x 10(-3)m, respectively. Succinoxidase activity of the same preparations was fully inhibited at a lower concentration, 2.5 x 10(-4)m. This concentration did not affect either succinic dehydrogenase or cytochrome oxidase, the primary and terminal enzymes of the succinoxidase complex. The nature of the intermediate step or steps inhibited at this concentration is not yet known. Gossypol was further shown to inhibit phosphorylation at concentrations having no appreciable effect on oxidation. Inhibition in general was not reduced by increased substrate concentrations in the enzyme systems examined, with the exception of cytochrome c for cytochrome oxidase. Bovine serum albumin was partially effective in reducing gossypol inhibition, provided that it was present before enzyme exposure to gossypol.