Myocardial angiogenesis: its absence makes the growing heart founder

Angiogenesis is essential for normal and neoplastic tissue growth. In a recent issue of Nature, Komuro and colleagues (Sano et al., 2007) describe how p53 expression in hypertrophying heart muscle impairs HIF-1-mediated neovascularization and contributes to functional decompensation of pressure-overload cardiac hypertrophy.     

Applications of ionic liquids in carbohydrate chemistry: a window of opportunities

Ionic liquids (ILs) are composed only of ions. Of special interest to this review are those where at least one ion (the cation) is organic and whose melting points are below or not far above room temperature. ILs are designated as "green" solvents because they have extremely low vapor pressure, are non-inflammable, and thermally and chemically stable. Therefore, many of them can be, in principle, recycled into the process indefinitely. The objective of the present review is to discuss different aspects of the use of ILs in carbohydrate chemistry, in particular, dissolution and functionalization of simple sugars, cyclodextrins, cellulose, starch, and chitin/chitosan. The molecular structure and synthesis of ILs most frequently employed in carbohydrate chemistry are discussed with an emphasis on imidazolium and pyridinium cations with different counterions. The physicochemical properties of ILs that are relevant to the dissolution and functionalization of carbohydrates, in particular their polarities and hydrogen-bonding abilities, are discussed. Dissolution of simple saccharides and biopolymers in ILs is presented with an emphasis on the mechanism of carbohydrate--IL interactions. Finally, the very interesting novel applications of the solutions obtained are addressed. These include, inter alia, spinning of the dissolved biopolymer into fibers, extrusion into slabs and rods, formation of matrixes for a myriad of substrates, including biomacromolecules, formation of nanocomposites, and functionalization to produce important derivatives. The use of ILs in many branches of science is expanding fast; it is hoped that this review will draw the attention of researchers to the "window of opportunities" that these green solvents open into carbohydrate chemistry.     

Mendelian randomization supports causality between maternal hyperglycemia and epigenetic regulation of leptin gene in newborns

Leptin is an adipokine that acts in the central nervous system and regulates energy balance. Animal models and human observational studies have suggested that leptin surge in the perinatal period has a critical role in programming long-term risk of obesity. In utero exposure to maternal hyperglycemia has been associated with increased risk of obesity later in life. Epigenetic mechanisms are suspected to be involved in fetal programming of long term metabolic diseases. We investigated whether DNA methylation levels near LEP locus mediate the relation between maternal glycemia and neonatal leptin levels using the 2-step epigenetic Mendelian randomization approach. We used data and samples from up to 485 mother-child dyads from Gen3G, a large prospective population-based cohort. First, we built a genetic risk score to capture maternal glycemia based on 10 known glycemic genetic variants (GRS₁₀) and showed it was an adequate instrumental variable (β = 0.046 mmol/L of maternal fasting glucose per additional risk allele; SE = 0.007; P = 7.8 × 10⁻¹¹; N = 467). A higher GRS₁₀ was associated with lower methylation levels at cg12083122 located near LEP (β = −0.072 unit per additional risk allele; SE = 0.04; P = 0.05; N = 166). Direction and effect size of association between the instrumental variable GRS₁₀ and methylation at cg12083122 were consistent with the negative association we observed using measured maternal glycemia. Lower DNA methylation levels at cg12083122 were associated with higher cord blood leptin levels (β = −0.17 log of cord blood leptin per unit; SE = 0.07; P = 0.01; N = 170). Our study supports that maternal glycemia is part of causal pathways influencing offspring leptin epigenetic regulation.     

Evi5 promotes collective cell migration through its Rab-GAP activity

Membrane trafficking has well-defined roles during cell migration. However, its regulation is poorly characterized. In this paper, we describe the first screen for putative Rab-GTPase-activating proteins (GAPs) during collective cell migration of Drosophila melanogaster border cells (BCs), identify the uncharacterized Drosophila protein Evi5 as an essential membrane trafficking regulator, and describe the molecular mechanism by which Evi5 regulates BC migration. Evi5 requires its Rab-GAP activity to fulfill its functions during migration and acts as a GAP protein for Rab11. Both loss and gain of Evi5 function blocked BC migration by disrupting the Rab11-dependent polarization of active guidance receptors. Altogether, our findings deepen our understanding of the molecular machinery regulating endocytosis and subsequently cell signaling during migration.     

Consumptive effects of fish reduce wetland crayfish recruitment and drive species turnover

Predators and dry-disturbances have pronounced effects on invertebrate communities and can deterministically affect compositional turnover between discrete aquatic habitats. We examined the effect of sunfish (Lepomis spp.) predators on two native crayfish, Procambarus alleni and P. fallax, that regionally coexist in an expansive connected wetland in order to test the hypotheses that sunfish predation limits crayfish recruitment (both species) and that it disproportionately affects P. alleni, the species inhabiting temporary wetlands. In replicate vegetated wetlands (18.6 m²), we quantified summertime crayfish recruitment and species composition across an experimental gradient of sunfish density. Separately, we quantified effects of sunfish on crayfish growth, conducted a complimentary predation assay in mesocosms, and compared behavior of the two crayfish. Sunfish reduced P. alleni summertime recruitment by >99% over the full sunfish gradient, and most of the effect was caused by low densities of sunfish (0.22–0.43 m⁻²). P. alleni dominated wetlands with few or no sunfish, but the composition shifted towards P. fallax dominance in wetlands with abundant sunfish. P. fallax survived better than P. alleni over 40 h in smaller mesocosms stocked with warmouth. Sunfish reduced P. fallax recruitment 62% in a second wetland experiment, but growth rates of caged crayfish (both species) were unaffected by sunfish presence, suggesting predatory effects were primarily consumptive. Consistent with life histories of relatively fish-sensitive invertebrates, P. alleni engaged in more risky behaviors in the laboratory. Our results indicate that sunfish predators limit recruitment of both species, but disproportionately remove the more active and competitively dominant P. alleni. Spatially and temporally variable dry-disturbances negatively co-varying with sunfish populations allow for regional coexistence of these two crayfish and may release populations of either species from control by predatory fishes.     

BNip3 regulates mitochondrial function and lipid metabolism in the liver

BNip3 localizes to the outer mitochondrial membrane, where it functions in mitophagy and mitochondrial dynamics. While the BNip3 protein is constitutively expressed in adult liver from fed mice, we have shown that its expression is superinduced by fasting of mice, consistent with a role in responses to nutrient deprivation. Loss of BNip3 resulted in increased lipid synthesis in the liver that was associated with elevated ATP levels, reduced AMP-regulated kinase (AMPK) activity, and increased expression of lipogenic enzymes. Conversely, there was reduced β-oxidation of fatty acids in BNip3 null liver and also defective glucose output under fasting conditions. These metabolic defects in BNip3 null liver were linked to increased mitochondrial mass and increased hepatocellular respiration in the presence of glucose. However, despite elevated mitochondrial mass, an increased proportion of mitochondria exhibited loss of mitochondrial membrane potential, abnormal structure, and reduced oxygen consumption. Elevated reactive oxygen species, inflammation, and features of steatohepatitis were also observed in the livers of BNip3 null mice. These results identify a role for BNip3 in limiting mitochondrial mass and maintaining mitochondrial integrity in the liver that has consequences for lipid metabolism and disease.     

Mobility of mass-reared diapaused and nondiapaused Cydia pomonella (Lepidoptera: Tortricidae): effect of mating status and treatment with gamma radiation

Mass-reared insects may differ in their behavioral traits depending on whether they have undergone diapause. We studied the mobility of mass-reared diapaused and nondiapaused Cydia pomonella (L.) with a focus on understanding the effect of mating status and treatment with gamma radiation as these insects are destined for use in an areawide program that uses the sterile insect technique (SIT). Actograph-measured mobility was assessed one gender at a time for 4 h during which the photoperiod transitioned from day to night. We tested 20-30 individuals per treatment. For experiments on the effect of mating status, we used 24-48-h-old adults (diapause [D]-virgin, D-mated, standard [N]-virgin, and N-mated), which is the typical age class that is released in the SIT program. Diapaused females were significantly more mobile than females reared through standard production, whereas no differences were detected in male mobility because of rearing strategy. Mated females were significantly more mobile than virgin females, whereas no difference in mobility because of mating status was detected for males. Mated females were significantly more mobile than mated males. In contrast, virgin females were significantly less mobile than virgin males. For experiments on the effect of treatment with gamma radiation, adults from all rearing strategies and treatments (D-0Gy, D-100Gy, D-250Gy, N-0Gy, N-100Gy, and N-250Gy), were tested simultaneously. Adult males were tested at two different constant temperatures (25 and 20 degrees C), whereas adult females were tested only at 25 degrees C. For standard-reared adults, we found a significant linear decrease in mobility as the radiation dose increased from 0 to 250 Gy. In contrast, the relationship between mobility and dose of radiation was quadratic for diapaused males and absent for diapaused females.     

Effect of plant architecture and hail nets on temperature of codling moth habitats in apple orchards

Plant architecture of apple trees in commercial orchards was rapidly changed from traditional tall trees to dwarf trees to optimize yield and fruit quality. Additionally, hail nets are widely used to prevent yield loss by hail. These changes are expected to considerably influence the orchard microclimate and thus the developmental rates of pest insects in apple. However, these relationships have not yet been fully elucidated. The present study was conducted over the seasonal cycle to investigate the influence of plant architecture and hail nets on the habitat temperatures of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), in apple, Malus domestica Borkh. (Rosaceae). Within the canopies, leaf area index (LAI) and global site factor (GSF) were quantified using hemispherical photography. Temperature was analysed for the main habitats of the different codling moth stages, i.e., air within the canopy, bark of tree stems, and apple fruit. In dwarf trees, LAI was lower, leading to a higher GSF than in tall trees. Hail nets did not influence LAI and GSF. Results for dwarf trees compare as follows with those for tall trees: Average air temperatures within the canopy were 0.7 °C higher during daytime, whereas 0.4 °C lower at night. Mean surface temperatures of bark were 0.9 °C higher on sunny and 0.4 °C on overcast days. Mean surface temperatures of apple fruits were 1.8–2.7 °C higher on sunny days, but 0.6 °C cooler on overcast days. The effect of hail nets was confined to a reduction of the air temperature within the canopy by approximately 0.2–0.8 °C. Bark and apple surface temperatures were not significantly affected. Based on the temperature differences in the habitats considered, the calculated development of the codling moth in dwarf trees was on average 3 days faster than in tall trees. The calculations imply a negligible effect of hail nets on codling moth development.     

Ambient temperature affects mechanosensory host location in a parasitic wasp

Certain parasitic wasps (Ichneumonidae, Pimplinae) use self-produced vibrations transmitted on plant substrate to locate their immobile concealed hosts (i.e. lepidopteran pupae). This mechanosensory mechanism, called the vibrational sounding, depends both on physical cues of the environment and physical activity of the parasitoid and is postulated to depend on ambient temperature. We analysed the influences of temperature on vibrational sounding by choice experiments using plant-stem models with hidden host mimics in the temperate species Pimpla turionellae. The results show a significant effect of temperature on host-location activity and on the success of this process. Outside an optimum range, the performance of the wasps decreased both at low and high temperatures. Below 10°C and beyond 24°C, the wasps displayed (1) substantial reduction in responsiveness, i.e. proportion of females showing ovipositor insertions, (2) reduction of quantitative activity with ovipositor insertions in the individuals, and (3) reduced precision of mechanosensory host location. Nevertheless, female wasps were able to locate their host over a surprisingly broad range of ambient temperatures which indicates that the wasps are able to compensate for temperature effects on vibrational sounding.     

Actomyosin tube formation in polar body cytokinesis requires Anillin in C. elegans

Polar body extrusion (PBE) is the specialized asymmetric division by which oocytes accomplish reduction in ploidy and retention of cytoplasm. During maternal gametogenesis, as in male meiosis and mitosis, cytokinesis is accomplished by a ring rich in active Rho, myosin, and formin-nucleated F-actin [1-7]. However, unlike mitosis, wherein the contractile ring encircles the cell equator, the polar body ring assembles as a discoid cortical washer. Here we show that in Caenorhabditis elegans, the meiotic contractile ring transforms during closure from a disc above the spindle to a cylinder around the spindle midzone. The meiotic midbody tube comprises stacked cytoskeletal rings. This topological transition suggests a novel mechanism for constriction of an initially discoid cytokinetic ring. Analysis of mouse PBE indicates that midbody tube formation is a conserved process. Depletion of the scaffold protein anillin (ANI-1) from C. elegans results in large and unstable polar bodies that often fuse with the oocyte. Anillin is dispensable for contractile ring assembly, initiation, and closure but is required for the meiotic contractile ring to transform from a disc into a tube. We propose that cytoskeletal bundling by anillin promotes formation of the midbody tube, which ensures the fidelity of PBE.