Presence and seasonal prevalence of Plasmodium spp. in a rare endemic New Zealand passerine (tieke or Saddleback, Philesturnus carunculatus)

The conservation and management of Saddlebacks (Philesturnus carunculatus) and other New Zealand birds, currently relies on the translocation of individuals to predator-free sites. Avian malaria has been identified as one of the diseases to be tested for prior to translocations in New Zealand, with the aim of translocating disease-free individuals. We describe avian malaria lineages and their seasonal prevalence in 2007-2008 in Saddlebacks from Mokoia Island, a source of birds for translocations, and investigate their pathogenicity. Three lineages of avian malaria were found at low prevalence (≤10.6%) and parasitemia (all but one infection were below 1/10,000 erythrocytes), typical of chronic infections. Two lineages clustered with previously identified lineages of Plasmodium relictum and one with a lineage of Plasmodium (Huffia) elongatum. Prevalence of malaria infection was higher in the spring with no significant difference in prevalence between juvenile and adult birds. We found no effect of stress on infections or any indication of pathogenicity.     

Synthesis of basic fibroblast growth factor upon differentiation of rat mammary epithelial to myoepithelial-like cells in culture

Acidic fibroblast growth factor (aFGF) mRNA was detected in a rat mammary fibroblastic cell line, but not in rat mammary epithelial cell lines or myoepithelial-like cell lines. Basic FGF (bFGF) mRNA was detected in both the fibroblasts and the myoepithelial-like cells, but was absent from the epithelial cells. A series of cell lines representing stages in the differentiation pathway of epithelial cells to a myoepithelial-like morphology showed an increase in the amount of bFGF mRNA and activity present and the FGF from the myoepithelial-like rat mammary 29 cells was able to displace [125I]-bFGF specifically bound to rat mammary fibroblasts. FGF activity was also present in an extract of rat mammary gland. Analysis of cell extracts and conditioned medium indicated that FGF activity was cell-associated. The cell-associated bFGF was resistant to degradation by trypsin. Extraction of myoepithelial-like cells with Triton X-100 and 2 M NaCl showed that 50-65% of the cell-associated bFGF was in a detergent-resistant but 2 M NaCl-labile structure. Thus, the synthesis of bFGF is developmentally regulated in rat mammary cell lines, and at least 50% is present in the extracellular matrix.     

Root growth,macro-nutrient uptake dynamics and soil fertility requirements of a high-yielding winter oilseed rape crop

Shoot growth, root growth and macro-nutrient uptake by a high-yielding (5t/ha grain) winter oilseed rape crop have been measured. Maximum rooting density in the top 20cm of soil was 9.4 cm cm⁻³ and roots reached a depth of at least 1.8 m. Maximum nutrient uptakes were 364 kg ha⁻¹ for N, 43 kg ha⁻¹ for P, 308 kg ha⁻¹ for K, 287 kg ha⁻¹ for Ca and 16 kg ha⁻¹ for Mg. A 30-day drought coincided with the flowering period and root and shoot growth, as well as nutrient uptake rates, were reduced. Nutrient concentrations in the soil solution necessary to sustain the nutrient fluxes into the root system by diffusive supply have been calculated. Peak values were in the range 10 μM for P to 87 μM for N, lower than the observed concentrations, and it was concluded that nutrient transport to roots was not a limitation to uptake by this rape crop.     

Cryptic diversity in the genus <Emphasis Type=Italic>Adineta</Emphasis> Hudson &; Gosse, 1886 (Rotifera: Bdelloidea: Adinetidae): a DNA taxonomy approach

Cryptic species are continuously discovered in rotifers using different methods to delineate these units of diversity. DNA taxonomy is the most effective method taxonomists have to untie potential cryptic taxa. Here, we estimate hidden diversity in a genus of bdelloid rotifers, Adineta. We analyse cryptic diversity using a coalescent approach to infer evolutionarily significant units from a phylogenetic tree obtained from cytochrome oxidase I sequences. Cryptic diversity was measured for eight traditional species and from several additional undetermined populations. Taxonomic inflation of up to 36 taxa was found in A. vaga from DNA taxonomy. As observed in other microscopic organisms, cryptic taxa within each traditional species were not geographically isolated, but had significantly narrower ecological niches than expected by chance alone.     

Speciation and DNA barcodes: testing the effects of dispersal on the formation of discrete sequence clusters

Large-scale sequencing of short mtDNA fragments for biodiversity inventories ('DNA barcoding') indicates that sequence variation in animal mtDNA is highly structured and partitioned into discrete genetic clusters that correspond broadly to species-level entities. Here we explore how the migration rate, an important demographic parameter that is directly related to population isolation, might affect variation in the strength of mtDNA clustering among taxa. Patterns of mtDNA variation were investigated in two groups of beetles that both contain lineages occupying habitats predicted to select for different dispersal abilities: predacious diving beetles (Dytiscidae) in the genus Bidessus from lotic and lentic habitats across Europe and darkling beetles (Tenebrionidae) in the genus Eutagenia from sand and other soil types in the Aegean Islands. The degree of genetic clustering was determined using the recently developed 'mixed Yule coalescent' (MYC) model that detects the transition from between-species to within-population branching patterns. Lineages from presumed stable habitats, and therefore displaying lower dispersal ability and migration rates, showed greater levels of mtDNA clustering and geographical subdivision than their close relatives inhabiting ephemeral habitats. Simulations of expected patterns of mtDNA variation under island models showed that MYC clusters are only detected when the migration rates are much lower than the value of Nm=1 typically used to define the threshold for neutral genetic divergence. Therefore, discrete mtDNA clusters provide strong evidence for independently evolving populations or species, but their formation is suppressed even under very low levels of dispersal.     

Using exon and intron sequences of the gene Mp20 to resolve basal relationships in Cicindela (Coleoptera:Cicindelidae)

The genus Cicindela (Coleoptera: Cicindelidae) is a species-rich cosmopolitan group of tiger beetles useful for comparing clade diversification worldwide. Knowledge about relationships of major groups is important for this analysis but basal nodes in Cicindela have been difficult to resolve with standard mtDNA markers. Here we developed the Mp20 gene, a single-copy nuclear marker coding for a muscle-associated protein in insects, for phylogenetic analysis of basal groups of Cicindela. Nearly full-length sequences were obtained for 51 cicindelids, including major taxonomic groups from all continents. Sequences of Mp20 were between 1.2 and 1.7 kb and spanning three introns. Phylogenetic signal of exon and intron sequences was compared with that from four gene regions of mtDNA (COI, COIII, Cytb, 16S rRNA; 2.4 kb total). Because introns differed in length, sequence alignment was conducted using various procedures of phenetic and parsimony-based character coding of indels to assess their phylogenetic information content, but major nodes were recovered consistently. Mp20 sequences contributed two thirds of the total support of the combined analysis, with most signal from the introns. We found major clades of Cicindela to be geographically largely coincident with continental regions, confined to Australasia, the Holarctic, the Indian subcontinent, Africa, and South and Central America. Clock estimates using various maximum-likelihood (ML) branch length calculations resulted in roughly similar divergence times whether Mp20 exon, introns, or mtDNA were used, and they were not greatly affected by different procedures for coding and optimizing indel characters. Based on existing clock calibrations in Cicindela, basal splits of continental lineages occurred in the mid-Miocene, placing the radiation of basal groups of Cicindela to a period when their open-vegetation habitats expanded globally.     

The crystal structure at 2A resolution of the Ca2+ -binding protein S100P

S100P is a small calcium-binding protein of the S100 EF-hand-containing family of proteins. Elevated levels of its mRNA are reported to be associated with the progression to hormone independence and metastasis of prostate cancer and to be associated with loss of senescence in human breast epithelial cells in vitro. The first structure of human recombinant S100P in calcium-bound form is now reported at 2.0A resolution by X-ray diffraction. A flexible linker connects the two EF-hand motifs. The protein exists as a homodimer formed by non-covalent interactions between large hydrophobic areas on monomeric S100P. Experiments with an optical biosensor to study binding parameters of the S100P monomer interaction showed that the association rate constant was faster in the presence of calcium than in their absence, whereas the dissociation rate constant was independent of calcium. The K(d) values were 64(+/-24)nM and 2.5(+/-0.8) microM in the presence and in the absence of calcium ions, respectively. Dimerization of S100P is demonstrated in vivo using the yeast two-hybrid system. The effect of mutation of specific amino acids suggests that dimerization in vivo can be affected by amino acids on the dimer interface and in the hydrophobic core.     

Difluoro analogue of UCS15A triggers activation of exogenously expressed c-Src in HCT 116 human colorectal carcinoma cells

UCS 15A, an antibiotic produced by Streptomyces sp., has been reported to specifically disrupt SH3 domain-mediated interactions in eukaryotic cells. Interestingly, in the case of the non-receptor tyrosine kinase Src, UCS15A was effective in suppressing the SH3 domain-mediated intermolecular rather than intramolecular interactions, and thus prevented Src interactions with certain downstream effectors without affecting Src kinase activity. Here the synthesis of a novel difluoro analogue of UCS15A is described. The effects of this compound (8) on Src activity were tested in HCT 116 colorectal carcinoma cells engineered for inducible expression of c-Src. The presence of compound (8) resulted in the increased activity of the induced c-Src implicating that (8) acts as a c-Src activator in vivo. These observations are supported by computer modelling studies which suggest that the aldehyde group of (8) may covalently bind to a lysine residue in the SH2-kinase linker region situated in the proximity of the SH3 domain, which could promote a conformational change resulting in increased Src activity.     

Invertebrate biodiversity in apple orchards: agrichemical sprays as explanatory variables for inter‐orchard community differences

相似文献