Molecular characterization and tissue distribution of a novel member of the S100 family of EF-hand proteins.

We have isolated from a human prostate cDNA library a cDNA encoding a novel member of the S100 family of EF-hand proteins. The encoded 99-amino acid protein, designated S100Z, is capable of interacting with another member of the family, S100P. S100Z cDNA was cloned into a bacterial expression system, and the S100Z protein was purified to homogeneity from bacterial lysates by a combination of hydrophobic column and gel-filtration chromatography. Direct amino acid sequencing of the 20 N-terminal amino acids confirmed that the sequence of the recombinant protein is identical to the sequence deduced from the cDNA. Low-resolution structural data have been obtained using circular dichroism and fluorescence spectroscopies, and equilibrium analytical centrifugation. These results show that S100Z is a dimeric, predominantly alpha-helical protein. Addition of calcium to a solution of S100Z changes the fluorescence intensity of the protein, indicating that S100Z is capable of binding calcium ions. Analysis of the calcium-binding isotherm indicates the existence of two calcium-binding sites with apparent affinities on the order of 5 x 10(6) and 10(2) M(-1). Binding of calcium results in conformational changes and exposure of hydrophobic surfaces on the protein. Using a PCR-based assay, we have detected differences in the expression level of S100Z mRNA in various tissues. The highest levels were found in spleen and leukocytes. S100Z gene expression appears to be deregulated in some tumor tissues, compared to expression in their normal counterparts.     

Production of Diamino propionic acid ammonia lyase by a new strain of Salmonella typhimurium PU011

Background  

Seeds of the legume plant Lathyrus sativus, which is grown in arid and semi arid tropical regions, contain Diamino Propionic acid (DAP). DAP is a neurotoxin, which, when consumed, causes a disease called Lathyrism. Lathryrism may manifest as Neurolathyrism or Osteolathyrism, in which the nervous system, and bone formation respectively, are affected. DAP ammonia lyase is produced by a few microorganisms such as Salmonella typhi, Salmonella typhimurium and Pseudomonas, and is capable of detoxifying DAP.     

Plant mineral nutrition in ancient landscapes: high plant species diversity on infertile soils is linked to functional diversity for nutritional strategies

Ancient landscapes, which have not been glaciated in recent times or disturbed by other major catastrophic events such as volcanic eruptions, are dominated by nutrient-impoverished soils. If these parts of the world have had a relatively stable climate, due to buffering by oceans, their floras tend to be very biodiverse. This review compares the functional ecophysiological plant traits that dominate in old, climatically buffered, infertile landscapes (OCBILS) with those commonly found in young, frequently disturbed, fertile landscapes (YODFELs). We show that, within the OCBILs of Western Australia, non-mycorrhizal species with specialised root clusters predominantly occur on the most phosphate-impoverished soils, where they co-occur with mycorrhizal species without such specialised root clusters. In global comparisons, we show that plants in OCBILs, especially in Western Australia, are characterised by very low leaf phosphorus (P) concentrations, very high N:P ratios, and very high LMA values (LMA = leaf mass per unit leaf area). In addition, we show that species in OCBILs are far more likely to show P-toxicity symptoms when exposed to slightly elevated soil P levels when compared with plants in YODFELs. In addition, some species in OCBILs exhibit a remarkable P-resorption proficiency, with some plants in Western Australia achieving leaf P concentrations in recently shed leaves that are lower than ever reported before. We discuss how this knowledge on functional traits can guide us towards sustainable management of ancient landscapes.     

An Autoradiographic Study of the Developing Parietal Cell Population In Neonatal Pigs

Abstract. Autoradiographic labelling using tritiated thymidine ([³H]TdR) was used to examine the pattern of development of gastric parietal cells in newborn pigs. Specific objectives were to establish sites in the gland where cells with a characteristic parietal cell morphology first appear, the extent of their migration or displacement, and the kinetics of any development and migration that occurs. Five newly-born littermate piglets were given a virtually continuous label of [³H]TdR over 24 hr, sacrificed at 1, 3, 5, 7 and 10 days thereafter, and samples of the gastric mucosa taken. the percentage of labelled parietal cells as a function of position in the oxyntic gland was measured for each pig. A generalized log linear model was fitted to the data using the statistical package GLIM, confirming a significant trend for labelled cells to occupy higher sites in the oxyntic gland as the time since labelling of cells increased. Goodness of fit tests showed that the trend effect was highly unlikely to be due to the variability of cell distribution from animal to animal. the dynamics of the parietal cell population and the strengths of GLIM for analysing cell labelling data are discussed.     

Orchid biogeography and factors associated with rarity in a biodiversity hotspot,the Southwest Australian Floristic Region

Aim The causes of orchid diversification and intrinsic rarity are poorly resolved. The Orchidaceae of the Southwest Australian Floristic Region use a diversity of pollination strategies and sites of mycorrhizal infection, and occupy a diversity of habitats. We combined a biogeographic analysis with analysis of factors associated with rarity to establish: (1) the landscape features correlated with taxon turnover and speciation, and (2) the possible role in taxon rarity of geographic region, pollination strategy, edaphic habitat and site of mycorrhizal infection. Location Southwest Australian Floristic Region. Methods The distributions of 407 orchid taxa (species and subspecies) were mapped at the quarter‐degree scale using 13,267 collections in the Western Australian Herbarium. This database was used to map taxon richness, for a biogeographic analysis and to quantify rarity of taxa. Using herbarium records, rarity was expressed as mean abundance, mean distribution and incidence of rarity based on abundance and distribution for each genus. We tested for differences in rarity of species between pollination strategies, edaphic habitats and sites of mycorrhizal infection. Results Taxon richness was highest in the High Rainfall Province. Biogeographic provincial boundaries for orchids were aligned with rainfall, while district boundaries tended to follow geological formations. When rarity was defined as either low abundance or small distribution, the greatest number of rare taxa occurred in areas of high taxon richness and naturally fragmented edaphic environments. For both abundance and distributional extent, sexual deception had a significantly higher incidence of rarity than food‐rewarding taxa. There was no significant difference in rarity with site of mycorrhizal infection. Main conclusions While large‐scale edaphic and climatic variation are correlated with orchid taxon turnover and speciation in a similar fashion to the flora in general, the processes responsible for patterns of diversity may differ. Fragmented edaphic environments appear to be associated with a higher incidence of rare species due to limited dispersal/colonization opportunities or radiations of taxa in allopatry. The high incidence of rarity in sexually deceptive taxa could be due to either low fruit set or the risk of specializing on a single pollinator species.     

Commentary: On the Transformation of the Moral Economy of Care

The documentation amassed in these provisionalassessments of the changing terms andconditions of psychiatric work amounts to areconfiguring of the moral economy of care –those root value-laden assumptions about whatconstitutes proper conduct in a service ortreatment context. Such a transformationappears to have been in the works for sometime, but the acuity with which it afflicts theconsciousness of present-day actors suggeststhat a threshold has been crossed. The loss of``slippage' in everyday clinical work, limitedrecourse of those who would resist the trend,deep ``persuasive' impact on non-believers ofbeing forced to ``go through the motions,' allargue that the ethos of psychiatric work hasbeen thoroughly infiltrated by efficiency, withcosts yet to be reckoned. Anthropology mayhave been slow to take cognizance of suchtrends, but its improvisational methods andflexible tools should be of use in mapping suchcosts, direct and indirect, and anycountervailing benefits.     

Actin-binding Verprolin Is a Polarity Development Protein Required for the Morphogenesis and Function of the Yeast Actin Cytoskeleton

Yeast verprolin, encoded by VRP1, is implicated in cell growth, cytoskeletal organization, endocytosis and mitochondrial protein distribution and function. We show that verprolin is also required for bipolar bud-site selection. Previously we reported that additional actin suppresses the temperature-dependent growth defect caused by a mutation in VRP1. Here we show that additional actin suppresses all known defects caused by vrp1-1 and conclude that the defects relate to an abnormal cytoskeleton. Using the two-hybrid system, we show that verprolin binds actin. An actin-binding domain maps to the LKKAET hexapeptide located in the first 70 amino acids. A similar hexapeptide in other acting-binding proteins was previously shown to be necessary for actin-binding activity. The entire 70– amino acid motif is conserved in novel higher eukaryotic proteins that we predict to be actin-binding, and also in the actin-binding proteins, WASP and N-WASP. Verprolin-GFP in live cells has a cell cycle-dependent distribution similar to the actin cortical cytoskeleton. In fixed cells hemagglutinin-tagged Vrp1p often co-localizes with actin in cortical patches. However, disassembly of the actin cytoskeleton using Latrunculin-A does not alter verprolin's location, indicating that verprolin establishes and maintains its location independent of the actin cytoskeleton. Verprolin is a new member of the actin-binding protein family that serves as a polarity development protein, perhaps by anchoring actin. We speculate that the effects of verprolin upon the actin cytoskeleton might influence mitochondrial protein sorting/function via mRNA distribution.