Evolution of spore release mechanisms in the saprolegniaceae (Oomycetes): evidence from a phylogenetic analysis of internal transcribed spacer sequences

Classical studies on spore release within the Saprolegniaceae (Oomycetes) led to the proposition that different mechanisms of sporangial emptying represent steps in an evolutionary transition series. We have reevaluated this idea in a phylogenetic framework using internal transcribed spacer sequences of four genera. These data were compared with the response to osmotic stress exhibited by each taxon. Saprolegnia emerges as the most basal genus, sister to Achlya, Thraustotheca, and Dictyuchus. Achlya and Thraustotheca are most closely related, while Dictyuchus appears to have evolved along a separate evolutionary lineage. The resulting phylogenetic framework is consistent with the idea that the mechanism of sporangial emptying exhibited by Saprolegnia represents the plesiomorphic condition from which the other mechanisms were derived independently. These alternative mechanisms of spore release may have resulted from a small number of mutations that inhibited axonemal development and altered the temporal and spatial expression of lytic enzymes that degrade the sporangial wall. Copyright 1998 Academic Press.     

Components of soft tissue deformations in subjects with untreated angle's Class III malocclusions: thin-plate spline analysis

While the dynamics of maxillo-mandibular allometry associated with treatment modalities available for the management of Class III malocclusions currently are under investigation, developmental aberration of the soft tissues in untreated Class III malocclusions requires specification. In this study, lateral cephalographs of 124 prepubertal European-American children (71 with untreated Class III malocclusion; 53 with Class I occlusion) were traced, and 12 soft-tissue landmarks digitized. Resultant geometries were scaled to an equivalent size and mean Class III and Class I configurations compared. Procrustes analysis established statistical difference (P < 0.001) between the mean configurations. Comparing the overall untreated Class III and Class I configurations, thin-plate spline (TPS) analysis indicated that both affine and non-affine transformations contribute towards the deformation (total spline) of the averaged Class III soft tissue configuration. For non-affine transformations, partial warp 8 had the highest magnitude, indicating large-scale deformations visualized as a combination of columellar retrusion and lower labial protrusion. In addition, partial warp 5 also had a high magnitude, demonstrating upper labial vertical compression with antero-inferior elongation of the lower labio-mental soft tissue complex. Thus, children with Class III malocclusions demonstrate antero-posterior and vertical deformations of the maxillary soft tissue complex in combination with antero-inferior mandibular soft tissue elongation. This pattern of deformations may represent gene-environment interactions, resulting in Class III malocclusions with characteristic phenotypes, that are amenable to orthodontic and dentofacial orthopedic manipulations.     

Fatty acid composition of the postmortem prefrontal cortex of adolescent male and female suicide victims

Prior epidemiological, prospective intervention, and peripheral and central fatty acid composition studies suggest that omega-3 fatty acid deficiency may be associated with the pathoaetiology of depression and suicide. In the present study, we determined the fatty acid composition of the postmortem prefrontal cortex (PFC) of adolescent male and female suicide victims and age-matched controls. Fatty acid composition (wt% total fatty acids) and concentrations (μmol/g) were determined in the postmortem PFC (Brodmann area 10) of male and female adolescent (aged 13–20 years) suicide victims (n=20) and age-matched controls (n=20) by gas chromatography. None of the major polyunsaturated fatty acids including the principle brain omega-3 fatty acid, docosahexaenoic acid (DHA), monounsaturated fatty acids, or saturated fatty acids differed significantly between adolescent suicide victims and controls before or after segregation by gender. The arachidonic acid (AA, 20:4n-6): DHA ratio and adrenic acid (22:4n-6) composition were negatively correlated with age at death in controls but not in suicides, and males exhibited a greater AA:DHA ratio irrespective of cause-of-death. These results demonstrate that adolescent male and female suicide victims do not exhibit DHA deficits in the postmortem PFC relative to age-matched controls, and suggest that suicide victims do not exhibit the normal age-related decrease in adrenic acid composition and the AA:DHA ratio.     

Indolizine‐Based Donors as Organic Sensitizer Components for Dye‐Sensitized Solar Cells

Strong electron‐donating functionality is desirable for many organic donor‐π‐bridge‐acceptor (D‐π‐A) dyes. Strategies for increasing the electron‐donating strength of common nitrogen‐based donors include planarization of nitrogen substituents and the use of low resonance‐stabilized energy aromatic ring‐substituted nitrogen atoms. Organic donor motifs based on the planar nitrogen containing heterocycle indolizine are synthesized and incorporated into dye‐sensitized solar cell (DSC) sensitizers. Resonance active substitutions at several positions on indolizine in conjugation with the D‐π‐A π‐system are examined computationally and experimentally. The indolizine‐based donors are observed to contribute electron density with strengths greater than triarylamines and diarylamines, as evidenced by UV/Vis, IR absorptions, and oxidation potential measurements. Fluorescence lifetime studies in solution and on TiO₂ yield insights in understanding the performance of indolizine‐based dyes in DSC devices.     

Implications of land‐use change to Short Rotation Forestry in Great Britain for soil and biomass carbon

Land‐use change can have significant impacts on soil and aboveground carbon (C) stocks and there is a clear need to identify sustainable land uses which maximize C mitigation potential. Land‐use transitions from agricultural to bioenergy crops are increasingly common in Europe with one option being Short Rotation Forestry (SRF). Research on the impact on C stocks of the establishment of SRF is limited, but given the potential for this bioenergy crop in temperate climates, there is an evident knowledge gap. Here, we examine changes in soil C stock following the establishment of SRF using combined short (30 cm depth) and deep (1 m depth) soil cores at 11 sites representing 29 transitions from agriculture to SRF. We compare the effects of tree species including 9 coniferous, 16 broadleaved and 4 Eucalyptus transitions. SRF aboveground and root biomass were also estimated in 15 of the transitions using tree mensuration data allowing assessments of changes in total ecosystem C stock. Planting coniferous SRF, compared to broadleaved and Eucalyptus SRF, resulted in greater accumulation of litter and overall increased soil C stock relative to agricultural controls. Though broadleaved SRF had no overall effect on soil C stock, it showed the most variable response suggesting species‐specific effects and interactions with soil types. While Eucalyptus transitions induced a reduction in soil C stocks, this was not significant unless considered on a soil mass basis. Given the relatively young age and limited number of Eucalyptus plantations, it is not possible to say whether this reduction will persist in older stands. Combining estimates of C stocks from different ecosystem components (e.g., soil, aboveground biomass) reinforced the accumulation of C under coniferous SRF, and indicates generally positive effects of SRF on whole‐ecosystem C. These results fill an important knowledge gap and provide data for modelling of future scenarios of LUC.     

Soil Methane Sink Capacity Response to a Long-Term Wildfire Chronosequence in Northern Sweden

Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO₂ into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH₄). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH₄ oxidation in boreal forests. We measured soil CH₄ oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH₄ oxidation rates. We suggest that this increase in net CH₄ oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH₄ oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH₄ sink could be diminished.     

A multiplex biomarker approach for the diagnosis of transitional cell carcinoma from canine urine

Transitional cell carcinoma (TCC), the most common cancer of the urinary bladder in dogs, is usually diagnosed at an advanced disease stage with limited response to chemotherapy. Commercial screening tests lack specificity and current diagnostic procedures are invasive. A proof of concept pilot project for analyzing the canine urinary proteome as a noninvasive diagnostic tool for TCC identification was conducted. Urine was collected from 12 dogs in three cohorts (healthy, urinary tract infection, TCC) and analyzed using liquid chromatography tandem mass spectrometry. The presence of four proteins (macrophage capping protein, peroxiredoxin 5, heterogeneous nuclear ribonucleoproteins A2/B, and apolipoprotein A1) was confirmed via immunoblot. Of the total 379 proteins identified, 96 were unique to the TCC group. A statistical model, designed to evaluate the accuracy of this multiplex biomarker approach for diagnosis of TCC, predicted the presence of disease with 90% accuracy.     

Treatment of Helicobacter pylori infection 2010

It is accepted that the success of Helicobacter pylori eradication treatment using standard triple therapy is declining. Resistance, particularly to clarithromycin, has been shown in numerous countries to be rising to a level where the use of standard triple therapy in its current form may no longer be justified. The two major factors influencing resistance are prior exposure to the antibiotic and compliance with therapy. Regimes based on bismuth and levofloxacin, which had previously been mainly second-line options, are now emerging as superior first-line options. Trials of sequential and concomitant therapies are also showing the usefulness of these treatments in different populations. Options for third and subsequent line therapies include furazolidone and rifabutin-based regimes. Susceptibility testing should be performed to maintain accurate data on resistance levels, and has also clinical utility in difficult to eradicate cases. None of these, however, will be successful unless compliance is improved upon. If compliance is assured and eradication confirmation pursued, it has been repeatedly illustrated that near full eradication is achievable.     

Regulation and execution of molecular disassembly and catabolism during senescence

Senescence is a highly orchestrated developmental stage in the life cycle of plants. The onset of senescence is tightly controlled by signaling cascades that initiate changes in gene expression and the synthesis of new proteins. This complement of new proteins includes hydrolytic enzymes capable of executing catabolism of macromolecules, which in turn sets in motion disassembly of membrane molecular matrices, leading to loss of cell function and, ultimately, complete breakdown of cellular ultrastructure. A distinguishing feature of senescence that sets it apart from other types of programmed cell death is the recovery of carbon and nitrogen from the dying tissue and their translocation to growing parts of the plant such as developing seeds. For this to be accomplished, the initiation of senescence and its execution have to be meticulously regulated. For example, the initiation of membrane disassembly has to be intricately linked with the recruitment of nutrients because their ensuing translocation out of the senescing tissue requires functional membranes. Molecular mechanisms underlying this linkage and its integration with the catabolism of macromolecules in senescing tissues are addressed.