Ross procedure: is the root replacement technique superior to the sub-coronary implantation technique? Long-term results.

There is controversy over the use of the Ross procedure with regard to the sub-coronary and root replacement technique and its long-term durability. A systematic review of the literature may provide insight into the outcomes of these two surgical subvariants. A systematic review of reports between 1967 and February 2013 on sub-coronary and root replacement Ross procedures was undertaken. Twenty-four articles were included and divided into (i) sub-coronary technique and (ii) root replacement technique. The 10-year survival rate for a mixed-patient population in the sub-coronary procedure was 87.3% with a 95% confidence interval (CI) of 79.7-93.4 and 89.1% (95% CI, 85.3-92.1) in the root replacement technique category. For adults, it was 94 vs 95.3% (CI, 88.9-98.1) and in the paediatric series it was 90 vs 92.7% (CI, 86.9-96.0), respectively. Freedom from reoperation at 10 years was, in the mixed population, 83.3% (95% CI, 69.9-93.4) and 93.3% (95% CI, 89.4-95.9) for sub-coronary versus root replacement technique, respectively. In adults, it was 98 vs 91.2% (95% CI, 82.4-295.8), and in the paediatric series 93.3 vs 92.0% (95% CI, 86.1-96.5) for sub-coronary versus root replacement technique, respectively. The Ross procedure arguably has satisfactory results over 5 and 10 years for both adults and children. The results do not support the advantages of the sub-coronary technique over the root replacement technique. Root replacement was of benefit to patients undergoing reoperations on neoaorta and for long-term survival in mixed series.

Dialogues of root-colonizing biocontrol pseudomonads

Among biocontrol agents that are able to suppress root diseases caused by fungal pathogens, root-colonizing fluorescent pseudomonads have received particular attention because many strains of these bacteria trigger systemic resistance in host plants and produce antifungal compounds and exoenzymes. In general, the expression of these plant-beneficial traits is regulated by autoinduction mechanisms and may occur on roots when the pseudomonads form microcolonies. Three major classes of antibiotic compounds reviewed here in detail (2,4-diacetylphloroglucinol, pyoluteorin and various phenazine compounds) are all produced under cell population density-dependent autoinduction control acting at transcriptional and post-transcriptional levels. This regulation can either be reinforced or attenuated by a variety of chemical signals emanating from the pseudomonads themselves, other microorganisms or root exudates. Signals stimulating biocontrol factor expression via the Gac/Rsm signal transduction pathway in the biocontrol strain Pseudomonas fluorescens CHA0 are synthesized by many different plant-associated bacteria, warranting a more detailed investigation in the future.

Dos cuestiones pendientes de la sintaxis de los pronombres átonos: enclisis como fenómeno asociado a las oraciones matrices y doble clítico en las construcciones perifrásticas = The Remainders of the Syntax of Clitics: Enclisis as a Root Phenomenon, and Clitic Doubling in Periphrastic Constructions

Conferència centrada en dos aspectes concrets de la sintaxi dels pronoms àtons: l' enclisis que es dona en algunes oracions subordinades de les variants iberromàniques modernes de l'oest peninsular i les configuracions de doble cíclic en les construccions perifràstiques

Seasonal changes of whole root system conductance by a drought-tolerant grape root system

The role of root systems in drought tolerance is a subject of very limited information compared with above-ground responses. Adjustments to the ability of roots to supply water relative to shoot transpiration demand is proposed as a major means for woody perennial plants to tolerate drought, and is often expressed as changes in the ratios of leaf to root area (AL:AR). Seasonal root proliferation in a directed manner could increase the water supply function of roots independent of total root area (AR) and represents a mechanism whereby water supply to demand could be increased. To address this issue, seasonal root proliferation, stomatal conductance (gs) and whole root system hydraulic conductance (kr) were investigated for a drought-tolerant grape root system (Vitis berlandieri×V. rupestris cv. 1103P) and a non-drought-tolerant root system (Vitis riparia×V. rupestris cv. 101-14Mgt), upon which had been grafted the same drought-sensitive clone of Vitis vinifera cv. Merlot. Leaf water potentials (ψL) for Merlot grafted onto the 1103P root system (–0.91±0.02 MPa) were +0.15 MPa higher than Merlot on 101-14Mgt (–1.06±0.03 MPa) during spring, but dropped by approximately –0.4 MPa from spring to autumn, and were significantly lower by –0.15 MPa (–1.43±0.02 MPa) than for Merlot on 101-14Mgt (at –1.28±0.02 MPa). Surprisingly, gs of Merlot on the drought-tolerant root system (1103P) was less down-regulated and canopies maintained evaporative fluxes ranging from 35–20 mmol vine−1 s−1 during the diurnal peak from spring to autumn, respectively, three times greater than those measured for Merlot on the drought-sensitive rootstock 101-14Mgt. The drought-tolerant root system grew more roots at depth during the warm summer dry period, and the whole root system conductance (kr) increased from 0.004 to 0.009 kg MPa−1 s−1 during that same time period. The changes in kr could not be explained by xylem anatomy or conductivity changes of individual root segments. Thus, the manner in which drought tolerance was conveyed to the drought-sensitive clone appeared to arise from deep root proliferation during the hottest and driest part of the season, rather than through changes in xylem structure, xylem density or stomatal regulation. This information can be useful to growers on a site-specific basis in selecting rootstocks for grape clonal material (scions) grafted to them.

Radial transport of nutrients: the plant root as a polarized epithelium.

In higher plants, roots acquire water and soil nutrients and transport them upward to their aerial parts. These functions are closely related to their anatomical structure; water and nutrients entering the root first move radially through several concentric layers of the epidermis, cortex, and endodermis before entering the central cylinder. The endodermis is the innermost cortical cell layer that features rings of hydrophobic cell wall material called the Casparian strips, which functionally resemble tight junctions in animal epithelia. Nutrient uptake from the soil can occur through three different routes that can be interconnected in various ways: the apoplastic route (through the cell wall), the symplastic route (through cellular connections), and a coupled trans-cellular route (involving polarized influx and efflux carriers). This Update presents recent advances in the radial transport of nutrients highlighting the coupled trans-cellular pathway and the roles played by the endodermis as a barrier.

Usefulness of double locus sequence typing (DLST) for regional and international epidemiological surveillance of methicilin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial infections worldwide. To differentiate reliably among S. aureus isolates, we recently developed double locus sequence typing (DLST) based on the analysis of partial sequences of clfB and spa genes. In the present study, we evaluated the usefulness of DLST for epidemiological investigations of MRSA by routinely typing 1242 strains isolated in Western Switzerland. Additionally, particular local and international collections were typed by pulsed field gel electrophoresis (PFGE) and DLST to check the compatibility of DLST with the results obtained by PFGE, and for international comparisons. Using DLST, we identified the major MRSA clones of Western Switzerland, and demonstrated the close relationship between local and international clones. The congruence of 88% between the major PFGE and DLST clones indicated that our results obtained by DLST were compatible with earlier results obtained by PFGE. DLST could thus easily be incorporated in a routine surveillance procedure. In addition, the unambiguous definition of DLST types makes this method more suitable than PFGE for long-term epidemiological surveillance. Finally, the comparison of the results obtained by DLST, multilocus sequence typing, PFGE, Staphylococcal cassette chromosome mec typing and the detection of Panton-Valentine leukocidin genes indicated that no typing scheme should be used on its own. It is only the combination of data from different methods that gives the best chance of describing precisely the epidemiology and phylogeny of MRSA.

Injection of partially purified estrogen receptor protein from Xenopus liver nuclei into oocytes activates the silent vitellogenin locus.

Injection of extracts from Xenopus liver nuclei that are enriched 2000 times in estradiol receptor into Xenopus oocytes induces transcription of the silent vitellogenin locus, which is activated in liver by estradiol, but not of the albumin locus, which is active in liver but suppressed by high levels of estradiol. Transcription initiates within the 5'-end region of the gene we have studied and probably continues into the 3' third. The activation seems to be very efficient, but most of the primary transcripts are probably rapidly and inaccurately processed. New proteins are also made and secreted by the oocytes.

Adesão ao tratamento da dor crônica e o locus de controle da saúde

Objetivou-se avaliar a adesão dos doentes com dor crônica não oncológica ao tratamento e identificar relações entre a crença de controle da saúde e a adesão. Trinta doentes foram avaliados durante seis meses, em cinco entrevistas. A adesão foi classificada em plena, parcial e não adesão, e foi calculado o Índice de Acerto de Ingestão Medicamentosa (IAIM). A crença de controle da saúde foi avaliada por meio da Escala de Locus de Controle da Saúde. Observaram-se altos índices de adesão parcial e não adesão ao tratamento (40,0% a 56,7%), médias do IAIM entre 57,2% e 69,5%, e que doentes com crenças de maior "internalidade" aderiram menos ao tratamento.

Single loci with major effects in fire ants : the effects of the complementary sex-determining locus and the green beard supergene on gene expression

Etant données la complexité et la redondance des réseaux de gènes influençant de nombreux phénotypes, l'étude des rares cas d'un locus unique ayant des effets importants sur de nombreux phénotypes peut fournir des informations cruciales sur l'évolution des traits complexes. Nous avons séquencé le génome de la fourmi de feu Solenopsis invicta pour étudier comment l'expression des gènes détermine les effets majeurs et étendus de deux loci uniques sur le phénotype. Le premier locus concerne la détermination du sexe par le modèle des allèles complémentaires. Ce locus est connu pour déterminer le sexe chez tous les hyménoptères mais n'a été caractérisé que chez les abeilles. Les hétérozygotes pour ce locus se développent en reines diploïdes (ou ouvrières stériles) alors que les homozygotes se développent en mâles diploïdes incapables de produire du sperme et les hémizygotes en mâles haploïdes fertiles. Nous avons comparé l'expression des gènes entre les reines et les deux types de mâles au stade pupe, ainsi que 1 et 11 jours après l'émergence. Nous avons trouvé un changement prononcé de l'expression des gènes chez les mâles diploïdes, passant de très proche de celle des reines au stade pupe à identique aux mâles haploïdes 11 jours après l'émergence. Cela signifie que les mâles diploïdes sont condamnés à être stériles parce que les effets après émergence du locus de détermination du sexe ne per¬mettent pas d'effacer les effets de la ploïdie sur l'expression des gènes pendant le stade pupe, quand la spermatogénèse prend place. Le second locus aux effets majeurs que nous avons étudié est le supergène dit "green beard", qui consiste en 616 gènes couvrant 55% d'un chromosome (13 Mb) et est caractérisé par une absence de recombinaison entre les deux variants du supergène : "Social B" et "Social b" (SB et Sb). Au travers de l'effet "green beard", par lequel les ouvrières avec le supergène Sb discriminent favorablement les reines qui partagent ce supergène de façon perceptible, le génotype des reines fondatrices au niveau de ce supergène détermine l'organisation de la colonie : soit elle contient une seule reine SB/SB, soit plusieurs reines SB/Sb. Nous avons montré que le chromosome Sb a évolué comme le chromosome Y, accumulant probablement des allèles favorables dans des colonies avec plusieurs reines mais défavorables dans des colonies avec une seule reine (cf. gènes sexuellement antagonistes), ainsi que des transposons et des séquences répéti¬tives. Nous avons également montré que le polymorphisme du supergène cause de grandes différences d'expression chez les ouvrières et particulièrement les reines mais pas chez les mâles. Pour comprendre comment le polymorphisme du supergène chez les reines peut affecter l'organisation de la colonie, nous avons comparé l'expression entre les génotypes SB/SB et SB/Sb chez des reines vierges (1 et 11 jours) et des reines matures. Nous avons montré que les reines SB/SB sur-régulent des gènes impliqués dans la reproduction, expli-quant pourquoi elle grandissent plus rapidement et peuvent fonder des colonies de façon indépendante, tandis que les reines SB/Sb (qui ne peuvent fonder une nouvelle colonie) sur-régulent des gènes de signalement chimique qui affectent l'organisation des colonies par l'effet "green beard". - Given the complexity and redundancy of the gene networks that underlie many pheno- types, the study of rare cases of a single locus having major effects on many phenotypes can give powerful insights into the evolution of complex traits. We sequenced the genome of Solenopsis invicta fire ants to study how gene expression mediates the widespread major effects of two single loci on phenotype. The first is the complementary sex-determining locus, which is known to exist in most Hymenoptera despite being characterized only for honeybees. Heterozygotes at this locus become diploid queens (or sterile workers), homozy¬gotes become aspermic diploid males, and hemizygotes become fertile haploid males. We compared gene expression between queens and both types of males in pupae and 1 and 11 days after eclosion. We found a pronounced shift in gene expression in diploid males, from being nearly identical to queens as pupae to identical to haploid males 11 days after eclosion. This means that diploid males are condemned to sterility because the overriding effects of the sex locus after eclosion cannot undo the ploidy effects on expression during the pupal stage, when spermatogenesis must be completed. The second locus with major ef¬fects that we studied was the so-called "green beard" supergene, which consists of 616 genes encompassing 55% of one chromosome (13 Mb), without recombination between the two variants "Social B" and "Social b" (SB and Sb) supergene. Through the green beard effect, i.e. workers with the Sb supergene discriminating in favor of queens who perceptibly share this supergene, the founding queen's genotype at the supergene determines colony organi¬zation: either headed by a single SB/SB queen or many SB/Sb queens. We show that the Sb chromosome evolved like a Y-chromosome, probably accumulating alleles beneficial in multi-queen colonies but disadvantageous in single-queen colonies (cf. sexually antagonistic genes), as well as transposons and repetitive sequences. We also show that the polymor¬phism of the supergene causes widespread expression differences in workers and especially queens but not in males. To understand how the polymorphism at the supergene in queen can transform colony organization, we compared the expression between SB/SB and SB/Sb virgin queens (1 and 11 days) and mother queens. We show that SB/SB queens up-regulate genes involved in reproduction, explaining why they mature faster and can found colonies independently, while SB/Sb queens (which cannot found colonies) up-regulate chemical signaling genes that can transform colonies through the green beard effect.

Natural genetic variation of root system architecture from Arabidopsis to Brachypodium: towards adaptive value.

Root system architecture is a trait that displays considerable plasticity because of its sensitivity to environmental stimuli. Nevertheless, to a significant degree it is genetically constrained as suggested by surveys of its natural genetic variation. A few regulators of root system architecture have been isolated as quantitative trait loci through the natural variation approach in the dicotyledon model, Arabidopsis. This provides proof of principle that allelic variation for root system architecture traits exists, is genetically tractable, and might be exploited for crop breeding. Beyond Arabidopsis, Brachypodium could serve as both a credible and experimentally accessible model for root system architecture variation in monocotyledons, as suggested by first glimpses of the different root morphologies of Brachypodium accessions. Whether a direct knowledge transfer gained from molecular model system studies will work in practice remains unclear however, because of a lack of comprehensive understanding of root system physiology in the native context. For instance, apart from a few notable exceptions, the adaptive value of genetic variation in root system modulators is unknown. Future studies should thus aim at comprehensive characterization of the role of genetic players in root system architecture variation by taking into account the native environmental conditions, in particular soil characteristics.

Localization in sucrose gradients of the pyrophosphate-dependent proton transport of maize root membranes.

A maize (Zea mays L. cv LG 11) root homogenate was prepared and centrifuged to sediment the mitochondria. The pellet (6 KP) and the supernatant (6 KS) were collected and fractionated on linear sucrose density gradients. Marker enzymes were used to study the distribution of the different cell membranes in the gradients. The distribution of the ATP- and pyrophosphate-dependent proton pumping activities was similar after 3 hours of centrifugation of the 6 KS or the 6 KP fraction. The pumps were clearly separated from the mitochondrial marker cytochrome c oxidase and the plasmalemma marker UDP-glucose-sterolglucosyl-transferase. The pyrophosphate-dependent proton pump might be associated with the tonoplast, as the ATP-dependent pump, despite the lack of a specific marker for this membrane. However, under all the conditions tested, the two pumps overlapped the Golgi markers latent UDPase and glucan synthase I and the ER marker NADH-cytochrome c reductase. It is therefore not possible to exclude the presence of proton pumping activities on the Golgi or the ER of maize root cells. The two pumps (but especially the pyrophosphate-dependent one) were more active (or more abundant) in the tip than in the basal part of maize roots, indicating that these activities might be important in growth processes.

Target Molecular Size and Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis Analysis of the ATP-and Pyrophosphate-Dependent Proton Pumps from Maize Root Tonoplast.

Tonoplast-enriched membranes were prepared from maize (Zea mays L. cv LG 11) primary roots, using sucrose nonlinear gradients. The functional molecular size of the tonoplast ATP-and PPi-dependent proton pumps were analyzed by radiation inactivation. Glucose-6-phosphate dehydrogenase (G6PDH) was added as an internal standard. Frozen samples (-196 degrees C) of the membranes were irradiated with (60)Co for different periods of time. After thawing the samples, the activities of G6PDH, ATPase, and PPase were tested. By applying target theory, the functional sizes of the ATPase and PPase in situ were found to be around 540 and 160 kilodaltons, respectively. The two activities were solubilized and separated by gel filtration chromatography. The different polypeptides copurifying with the two pumps were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two bands (around 59 and 65 kilodaltons) were associated with the ATPase activity, whereas a double band (around 40 kilodaltons) was recovered with the PPase activity.

Differential proteoglycan expression in two spinal cord regions after dorsal root injury.

Dorsal root injury leads to reactive gliosis in the spinal cord dorsal root entry zone and dorsal column, two regions that undergo Wallerian degeneration, but have distinct growth-inhibitory properties. This disparity could in part be due to differences in the number of degenerating sensory fibers, differences in glial cell activation, and/or to differential expression of growth-inhibitory molecules such as chondroitin sulfate proteoglycans. Laser capture microdissection of these two spinal cord white matter regions, followed by quantitative analysis of mRNA expression by real-time PCR, revealed that glial marker transcripts were differentially expressed post-injury and that the chondroitin sulfate proteoglycans Brevican and Versican V1 and V2 were preferentially up-regulated in the dorsal root entry zone, but not the dorsal column. These results indicate that reactive gliosis differs between these two regions and that Brevican and Versican are potential key molecules participating in the highly inhibitory properties of the dorsal root entry zone.

Direct and indirect root defences of milkweed (Asclepias syriaca): trophic cascades, trade-offs and novel methods for studying subterranean herbivory

P>1. Entomopathogenic nematodes can function as indirect defence for plants that are attacked by root herbivores. By releasing volatile organic compounds (VOCs), plants signal the presence of host insects and thereby attract nematodes.2. Nonetheless, how roots deploy indirect defences, how indirect defences relate to direct defences, and the ecological consequences of root defence allocation for herbivores and plant biomass are essentially unknown.3. We investigate a natural below-ground tritrophic system, involving common milkweed, a specialist root-boring beetle and entomopathogenic nematodes, and asked whether there is a negative genetic correlation between direct defences (root cardenolides) and indirect defences (emission of volatiles in the roots and nematode attraction), and between constitutive and inducible defences.4. Volatiles of roots were analysed using two distinct sampling methods. First, we collected emissions from living Asclepias syriaca roots by dynamic headspace sampling. This method showed that attacked A. syriaca plants emit five times higher levels of volatiles than control plants. Secondly, we used a solid phase micro-extraction (SPME) method to sample the full pool of volatiles in roots for genetic correlations of volatile biosynthesis.5. Field experiments showed that entomopathogenic nematodes prevent the loss of biomass to root herbivory. Additionally, suppression of root herbivores was mediated directly by cardenolides and indirectly by the attraction of nematodes. Genetic families of plants with high cardenolides benefited less from nematodes compared to low-cardenolide families, suggesting that direct and indirect defences may be redundant. Although constitutive and induced root defences traded off within each strategy (for both direct and indirect defence, cardenolides and VOCs, respectively), we found no trade-off between the two strategies.6. Synthesis. Constitutive expression and inducibility of defences may trade off because of resource limitation or because they are redundant. Direct and indirect defences do not trade off, likely because they may not share a limiting resource and because independently they may promote defence across the patchiness of herbivore attack and nematode presence in the field. Indeed, some redundancy in strategies may be necessary to increase effective defence, but for each strategy, an economy of deployment reduces overall costs.