The South Hesse Oak Project (SHOP): Species- and site-specific efficiency of the photosynthetic apparatus of Mediterranean and Central European Oaks

In three experimental sites in Southern Hesse, differing in management procedures, one- to three-year-old saplings of Quercus robur, Q.pubescens, and Q.ilex were planted to study their performance under Central European climate conditions. Toward the end of the growth period (mid–late September 2011), during a very dry period, we measured JIP transients of photosystem II chlorophyll fluorescence induction curves to evaluate the effects of abiotic site factors on the photosynthetic apparatus by comparing them to data from well-watered saplings measured before the onset of senescence processes. In all three sites, Q. robur saplings in September showed the strongest deviation from the measurements in August, followed by Q. pubescens. Q. ilex, in general, was nearly unaffected by September climate conditions or performed better than plants measured in August. Differences in the behavior between species and sites could be explained by the species’ different drought susceptibility and by differential induction of early leaf senescence (in Q. robur and Q. pubescens). We conclude that measurement of the JIP transient is a feasible method in forestry to compare adverse microclimatic site effects and genetically fixed reactions of the photosynthetic apparatus in the field.     

Occurrence of species of the genus Pityophthorus Eichhoff (Coleoptera,Curculionidae, Scolytinae) in?the?province of Quebec,Canada

Twig beetles in the genus Pityophthorus Eichhoff, 1864 include more than 300 species worldwide, with maximum diversity in tropical and subtropical regions. To date, approximately 50 species of Pityophthorus have been recorded in Canada, and these species are associated mainly with coniferous trees. Since 1981, no comprehensive study on this difficult taxonomic group has been conducted in Quebec, Canada, most likely due to their limited significance as forest pests. Based on data gathered from five years of field sampling in conifer seed orchards and compiled from various entomological collections, the distribution of Pityophthorus species in Quebec is presented. Approximately 291 new localities were recorded for the Pityophthorus species. Five species-group taxa, namely Pityophthorus puberulus (LeConte, 1868), Pityophthorus pulchellus pulchellus Eichhoff, 1869, Pityophthorus pulicarius (Zimmermann, 1868), Pityophthorus nitidus Swaine, 1917,and Pityophthorus cariniceps LeConte&Horn, 1876 were the most widespread. In contrast, Pityophthorus consimilis LeConte, 1878, Pityophthorus intextus Swaine, 1917, Pityophthorus dentifrons Blackman, 1922, Pityophthorus ramiperda Swaine, 1917, and Pityophthorus concavus Blackman, 1928 display a notably limited distribution. In addition, the first distribution records of Pityophthorus intextus and Pityophthorus biovalis Blackman, 1922 are furnished, and the subspecies Pityophthorus murrayanae murrayanae Blackman, 1922is reported from Quebec for the second time. Moreover, distribution maps are provided for all Pityophthorus species recorded in the province of Quebec.     

Strong genetic differentiation due to multiple founder events during a recent range expansion of an introduced wall lizard population

Biological invasions represent ideal systems for the study of evolutionary processes associated with colonization events. It has been hypothesized that the genetic diversity is generally decreasing from the centre of the range to the margins due to multiple founder events. Invasive populations offer the opportunity to test this hypothesis at a fine spatial and temporal scale. We analysed the genetic structure of a large expanding non-native population of the Common Wall Lizard (Podarcis muralis) in Passau (Germany) using thirteen microsatellite loci. We analyzed the genetic structure and levels of admixture across a transect reflecting the expansion process and tested for a loss of genetic diversity and an increase of genetic differentiation from the centre to the invasion front. Our results demonstrate that significant genetic population structure can emerge rapidly at a small spatial scale. We found a trend for an increase in genetic differentiation and a decrease in genetic diversity from the invasion centre to the expanding range margin, suggesting that genetic drift is the major factor causing this pattern. The correlation between genetic diversity and average genetic differentiation was significant among sites. We hypothesize that the territoriality of P. muralis generates sufficient rates of noncontiguous and stratified dispersal from longer established sites to maintain significant genetic diversity at the invasion front. Simultaneously, territoriality might restrict the colonization success of migrants at established sites, so that in combination with founder events a strong differentiation arises.     

In vitro brown and “brite”/“beige” adipogenesis: Human cellular models and molecular aspects

Brown adipose tissue (BAT) has long been thought to be absent or very scarce in human adults so that its contribution to energy expenditure was not considered as relevant. The recent discovery of thermogenic BAT in human adults opened the field for innovative strategies to combat overweight/obesity and associated diseases. This energy-dissipating function of BAT is responsible for adaptive thermogenesis in response to cold stimulation. In this context, adipocytes can be converted, within white adipose tissue (WAT), into multilocular adipocytes expressing UCP1, a mitochondrial protein that plays a key role in heat production by uncoupling the activity of the respiratory chain from ATP synthesis. These adipocytes have been named “brite” or “beige” adipocytes. Whereas BAT has been studied for a long time in murine models both in vivo and in vitro, there is now a strong demand for human cellular models to validate and/or identify critical factors involved in the induction of a thermogenic program within adipocytes. In this review we will discuss the different human cellular models described in the literature and what is known regarding the regulation of their differentiation and/or activation process. In addition, the role of microRNAs as novel regulators of brown/“brite” adipocyte differentiation and conversion will be depicted. Finally, investigation of both the conversion and the metabolism of white-to-brown converted adipocytes is required for the development of therapeutic strategies targeting overweight/obesity and associated diseases. This article is part of a Special Issue entitled Brown and White Fat: From Signaling to Disease.     

Prediction of Severe Disease in Children with Diarrhea in a Resource-Limited Setting

Objective

To investigate the accuracy of three clinical scales for predicting severe disease (severe dehydration or death) in children with diarrhea in a resource-limited setting.

Methods

Participants included 178 children admitted to three Rwandan hospitals with diarrhea. A local physician or nurse assessed each child on arrival using the World Health Organization (WHO) severe dehydration scale and the Centers for Disease Control (CDC) scale. Children were weighed on arrival and daily until they achieved a stable weight, with a 10% increase between admission weight and stable weight considered severe dehydration. The Clinical Dehydration Scale was then constructed post-hoc using the data collected for the other two scales. Receiver Operator Characteristic (ROC) curves were constructed for each scale compared to the composite outcome of severe dehydration or death.

Results

The WHO severe dehydration scale, CDC scale, and Clinical Dehydration Scale had areas under the ROC curves (AUCs) of 0.72 (95% CI 0.60, 0.85), 0.73 (95% CI 0.62, 0.84), and 0.80 (95% CI 0.71, 0.89), respectively, in the full cohort. Only the Clinical Dehydration Scale was a significant predictor of severe disease when used in infants, with an AUC of 0.77 (95% CI 0.61, 0.93), and when used by nurses, with an AUC of 0.78 (95% CI 0.63, 0.93).

Conclusions

While all three scales were moderate predictors of severe disease in children with diarrhea, scale accuracy varied based on provider training and age of the child. Future research should focus on developing or validating clinical tools that can be used accurately by nurses and other less-skilled providers to assess all children with diarrhea in resource-limited settings.     

Two New Kremastochrysopsis species,K. austriaca sp. nov. and K. americana sp. nov. (Chrysophyceae)1

Melting summer snow in the Austrian Alps exhibited a yellowish bloom that was mainly comprised of an unidentified unicellular chrysophyte. Molecular data (18S rRNA and rbcL genes) showed a close relationship to published sequences from an American pond alga formerly identified as Kremastochrysis sp. The genera Kremastochrysis and Kremastochrysopsis are morphologically distinguished by the number of flagella observed with the light microscope, and therefore we assigned the Austrian snow alga and an American pond alga to the genus Kremastochrysopsis. Transmission and scanning electron microscopy revealed that swimming cells had two flagella oriented in opposite directions, typical for the Hibberdiales. Molecular phylogenetic analyses showed that both new species were closely related to Hibberdia. Kremastochrysopsis ocellata, the type species and only known species, has two chloroplasts per cell and the zoospores have red eyespots. Our two organisms had only a single chloroplast and no zoospore eyespot, but their gene sequences differed substantially. Therefore, we described two new species, Kremastochrysopsis austriaca sp. nov and Kremstochrysopsis americana sp. nov. When grown in culture, both taxa showed a characteristic hyponeustonic growth (hanging below the water surface), whereas older immotile cells grew at the bottom of the culture vessel. Ecologically, Kremastochrysopsis austriaca sp. nov., which caused snow discolorations, had no close phylogenetic relationships to other psychrophilic chrysophytes, for example, Chromulina chionophilia, Hydrurus sp., and Ochromonas-like flagellates.     

Comparison of Complex DNA Mixtures with Generic Oligonucleotide Microchips

Abstract

The reproducibility of melting curves for repeated hybridizations of target DNA with generic oligonucleotide microchips is shown experimentally to depend on the character of matching between fragments of target DNA and immobilized oligonucleotides. The reproducibility of melting curves is higher for the perfect match duplexes and decreases as the number of mismatched pairs within duplexes increases. This effect was applied to the comparative analysis of complex DNA mixtures. We developed a scheme in which we can identify and discriminate between the probe oligonucleotides responsible for the distinctions between target DNA mixtures. A scheme is illustrated by comparing DNA mixtures corresponding to VD-J genes connected with populations of mRNAs CDR3 TCR Vb (T-cell receptor beta complementarity determining region 3) from the thymus and pancreas of NOD mice. Our results demonstrate that generic microchips can be applied efficiently to the analysis of DNA mixtures.     

Metabolic products of soluble epoxide hydrolase are essential for monocyte chemotaxis to MCP-1 in vitro and in vivo

Monocyte chemoattractant protein-1 (MCP-1)-induced monocyte chemotaxis is a major event in inflammatory disease. Our prior studies have demonstrated that MCP-1-dependent chemotaxis requires release of arachidonic acid (AA) by activated cytosolic phospholipase A₂ (cPLA₂). Here we investigated the involvement of AA metabolites in chemotaxis. Neither cyclooxygenase nor lipoxygenase pathways were required, whereas pharmacologic inhibitors of both the cytochrome-P450 (CYP) and the soluble epoxide hydrolase (sEH) pathways blocked monocyte chemotaxis to MCP-1. To verify specificity, we demonstrated that the CYP and sEH products epoxyeiscosatrienoic acids (EETs) and dihydroxyeicosatrienoic acids (DHETs), respectively, restored chemotaxis in the presence of the inhibitors, indicating that sEH-derived products are essential for MCP-1-driven chemotaxis. Importantly, DHETs also rescued chemotaxis in cPLA₂-deficient monocytes and monocytes with blocked Erk1/2 activity, because Erk controls cPLA₂ activation. The in vitro findings regarding the involvement of CYP/sEH pathways were further validated in vivo using two complementary approaches measuring MCP-1-dependent chemotaxis in mice. These observations reveal the importance of sEH in MCP-1-regulated monocyte chemotaxis and may explain the observed therapeutic value of sEH inhibitors in treatment of inflammatory diseases, cardiovascular diseases, pain, and even carcinogenesis. Their effectiveness, often attributed to increasing EET levels, is probably influenced by the impairment of DHET formation and inhibition of chemotaxis.     

Fibulin-3, -4, and -5 Are Highly Susceptible to Proteolysis,Interact with Cells and Heparin,and Form Multimers

Extracellular short fibulins, fibulin-3, -4, and -5, are components of the elastic fiber/microfibril system and are implicated in the formation and homeostasis of elastic tissues. In this study, we report new structural and functional properties of the short fibulins. Full-length human short fibulins were recombinantly expressed in human embryonic kidney cells and purified by immobilized metal ion affinity chromatography. All three fibulins showed various levels of degradation after the purification procedure. N-terminal sequencing revealed that all three fibulins are highly susceptible to proteolysis within the N-terminal linker region of the first calcium-binding epidermal growth factor domain. Proteolytic susceptibility of the linker correlated with its length. Exposure of these fibulins to matrix metalloproteinase (MMP)-1, -2, -3, -7, -9, and -12 resulted in similar proteolytic fragments with MMP-7 and -12 being the most potent proteases. Fibulin-3 proteolysis was almost completely inhibited in cell culture by the addition of 25 μm doxycycline (a broad spectrum MMP inhibitor). Reducible fibulin-4 dimerization and multimerization were consistently observed by SDS-PAGE, Western blotting, and mass spectrometry. Atomic force microscopy identified monomers, dimers, and multimers in purified fibulin-4 preparations with sizes of ∼10–15, ∼20–25, and ∼30–50 nm, respectively. All short fibulins strongly adhered to human fibroblasts and smooth muscle cells. Although only fibulin-5 has an RGD integrin binding site, all short fibulins adhere at a similar level to the respective cells. Solid phase binding assays detected strong calcium-dependent binding of the short fibulins to immobilized heparin, suggesting that these fibulins may bind cell surface-located heparan sulfate.