238 research outputs found
Hydrogen emissions from Erebus volcano, Antarctica
International audienceThe continuous measurement of molecular hydrogen (H2) emissions from passively degassing volcanoes has recently been made possible using a new generation of low-cost electrochemical sensors. We have used such sensors to measure H2, along with SO2, H2O and CO2, in the gas and aerosol plume emitted from the phonolite lava lake at Erebus volcano, Antarctica. The measurements were made at the crater rim between December 2010 and January 2011. Combined with measurements of the long-term SO2 emission rate for Erebus, they indicate a characteristic H2 flux of 0.03 kg s-1 (2.8 Mg day-1). The observed H2 content in the plume is consistent with previous estimates of redox conditions in the lava lake inferred from mineral compositions and the observed CO2/CO ratio in the gas plume (∼0.9 log units below the quartz-fayalite-magnetite buffer). These measurements suggest that H2 does not combust at the surface of the lake, and that H2 is kinetically inert in the gas/aerosol plume, retaining the signature of the high-temperature chemical equilibrium reached in the lava lake. We also observe a cyclical variation in the H2/SO2 ratio with a period of ∼10 min. These cycles correspond to oscillatory patterns of surface motion of the lava lake that have been interpreted as signs of a pulsatory magma supply at the top of the magmatic conduit
Class III Orthodontic Camouflage: Is the “Ideal” Treatment Always the Best Option? A Documented Case Report
Angle’s Class III is one of the most complex malocclusions to treat. In nongrowing skeletal class III malocclusions, the choice between orthognathic surgery and camouflage treatment remains a challenge to the orthodontist. In class III borderline cases, clinicians are called to find the best compromise between functional and aesthetics outcomes, with the latter which often turns in avoiding worsening of profile characteristics, which makes the treatment of these patients quite challenging. This case report describes a borderline nongrowing patient with skeletal class III malocclusion, upper incisor proclination and spacing, lower crowding, and arch width discrepancy, which has already undergone previous orthodontic treatment. The orthodontic treatment involved the mandibular first premolar extraction, resulting in class I canine relation with good overjet and overbite as well as good arch coordination. The orthodontic camouflage improved the dental relationship with normalization of upper incisor inclination without a relevant retroclination of lower incisors; the skeletal facial pattern of the patient experienced a slight improvement. The tendency to skeletal class III has remained nearly unaffected. Treatment outcomes were stable after 1-year posttreatment follow-up
Modern biotechnological approaches toward sustainable viticulture
Conventional breeding does not allow the introgression of single traits without compromising the genetic background that characterize an elite cultivar. The exploitation of the new molecular techniques known as genome editing and cisgenesis make possible to modify or transfer single genes preserving all the characteristics selected with difficulty by breeders over a long-time span. To date, 27 QTLs have been associated with downy mildew disease resistance (Rpv1-Rpv27) and many of these have been employed in breeding programs for the introgression in genotypes of interest. Just in case of Rpv1 and Rpv3, however, the underlying genes have been identified and characterized. In both cases nucleotide-binding leucine rich repeat (NB-LRR) genes are present, codifying for receptors that act as cytoplasmic pathogen sensors, triggering a signal transduction pathway for cell-death mediated defense at the infection site.
One of the biggest drawbacks of traditional genetic engineered plants is represented by the presence of transgenes (often selection markers), usually perceived as unsafe by consumers. The cisgenic approach aims at circumventing this problem avoiding the presence of exogenous DNA, introducing only the desired trait by using native genes from Vitis species, interfertile with V. vinifera. Adopting this strategy, the already characterized resistance genes RPV3 and/or RPV1 will be introduced in some elite Vitis vinifera varieties, highly appreciated by the wine industry.
The outcomes will reduce the agrochemicals needs and the risks associated with their use, increasing the profitability of the vineyard and consumers\u2019 appreciation.
Flower tissues of Glera, Sangiovese and Pinot Nero have been collected from field and fruit cuttings grown plants and from fruiting cuttings and used as explants for the induction of somatic embryos.
PCR products of candidate genes, including native promoter and terminator, will be cloned in a suitable vector and transformed into competent E.coli. The gene sequences will be then isolated by PCR and cloned into a binary vector engineered with an inducible excision system. Transient expression assays will be used to evaluate the efficacy of the candidate genes into the different genetic backgrounds of the selected cultivars. The gene construct will be used for the transformation of grapevine embryogenic calli through A. tumefaciens infection. Infected calli will be transferred on selective media for the induction and germination of somatic embryos . Regenerated plantlets will hence be checked for the presence and expression of candidate genes. For the removal of exogenous sequences, chemical or thermal induction of the excision system will be used. Absence of Agrobacterium and backbone sequences will also be checked by PCR on transformants. Resistance and susceptibility to downy mildew will be tested on available material of interest by leaf disc bioassay or whole leaves inoculation of in-vitro and/or acclimatisedacclimatized plantlets
Trans-translation is an appealing target for the development of new antimicrobial compounds
Because of the ever-increasing multidrug resistance in microorganisms, it is crucial that we find and develop new antibiotics, especially molecules with different targets and mechanisms of action than those of the antibiotics in use today. Translation is a fundamental process that uses a large portion of the cell’s energy, and the ribosome is already the target of more than half of the antibiotics in clinical use. However, this process is highly regulated, and its quality control machinery is actively studied as a possible target for new inhibitors. In bacteria, ribosomal stalling is a frequent event that jeopardizes bacterial wellness, and the most severe form occurs when ribosomes stall at the 30-end of mRNA molecules devoid of a stop codon. Trans-translation is the principal and most sophisticated quality control mechanism for solving this problem, which would otherwise result in inefficient or even toxic protein synthesis. It is based on the complex made by tmRNA and SmpB, and because trans-translation is absent in eukaryotes, but necessary for bacterial fitness or survival, it is an exciting and realistic target for new antibiotics. Here, we describe the current and future prospects for developing what we hope will be a novel generation of trans-translation inhibitors
NPBTs FOR SUSTAINABLE VITICULTURE MANAGEMENT TO BIOTIC AND ABIOTIC STRESS
New plant breeding techniques (NPBTs) aim to overcome traditional breeding
limits for plant improvement to biotic and abiotic stresses satisfying the European Policies requirements that promote chemical input reduction and a more
sustainable agriculture.
We decided to apply genome editing (via CRISPR/Cas9) focusing on susceptibility genes to control powdery mildew: we chosen to knock-out two genes
belonging to MLO (Mildew Locus O) family: VvMLO7 and VvMLO6. The same
approach was used to cope with abiotic stresses, in specifc drought, performing a knock-out of four genes, two belonging to GST (Glutathione S-Transferase) and two to PME (Pectin Methyl Esterase) gene families.
In parallel to genome editing, we also applied cisgenesis to move the resistance locus RPV3-1 (Resistance to Plasmopara viticola) into economically important cultivars. This locus is formed by two di\ufb00erent genes that were inserted
individually and in combination to evaluate their e\ufb00ects.
One of the drawbacks linked to classical Agrobacterium tumefaciens mediated transformation is the insertion of unrelated transgene (e.g., antibiotic
resistance). These markers are required for transgenic plants selection, but
undesirable to be retained in commercial plants due to possible toxicity or allergenicity to humans and animals, in addition to their potential hazards for the
environment. To overcome these limits, we exploit an inducible excision system based on a Cre-lox recombinase technology controlled by a heat-shock
inducible promoter that will be activated once the transformation event(s) will
be confrmed. Embryogenic calli of Chardonnay, Glera, Microvine, Pinot Noir,
Sangiovese, were used in stable transformation with A. tumefaciens carrying
the genome editing construct with the MLO-guideRNAs and the cisgenic
construct carrying the two RPV3-1 genes. Embryogenic calli of rootstocks 110
Richter and SO4 were transformed with genome editing construct carrying
GST and PME guideRNAs in two independent transformations. Regenerated
embryos from all the transformation events are now under evaluation
Correction: Rheometry-on-a-chip: measuring the relaxation time of a viscoelastic liquid through particle migration in microchannel flows
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New plant breeding technologies towards a more sustainable viticulture
European grapevine cultivars are highly susceptible to many pathogens that are managed through large pesticide use. Nevertheless, the European policies promote pesticide use reduction and new environmentally friendly methods for a more sustainable agriculture. In this framework, grapevine genetic improvement could benefit from New Plant Breeding Technologies. In order to reduce fungal susceptibility, we will produce knock-out plants from embryogenic calli using CRISPR/Cas9 technology. Studies in barley reported the acquisition of powdery mildew resistance by knocking out susceptibility genes belonging to the MLO (Mildew Locus O) family. In this study,
our approach takes advantage from CRISPR/Cas9 technology to perform a multiple knockout of MLO genes. Among the 17 VvMLOs reported in grapevine we designed constructs to target VvMLO6 and VvMLO7. Golden Gate assembly was used to produce three different constructs (containing two guideRNAs for each gene) to knocking-out the targets singularly or by producing a double mutant. Usually, the genetic engineering techniques, mediated by A. tumefaciens, involve the insertion of exogenous selectable marker genes. These markers are required for selection of transgenic plants, but they are undesirable to be retained in commercial transgenic plants due to possible toxicity or allergenicity to humans and potential environmental hazard. To overcome these limits, we opted for a \u201cclean\u201d editing strategy developing an inducible excision system. This approach is based on a recombinase technology involving the Cre-loxP system from the P1 bacteriophage under a heat-shock inducible promoter to be activated once the editing event(s) will be confirmed. Obtainment of embryogenic calli is one of the main bottlenecks for application of CRISPR/Cas9: for two seasons, we collected inflorescences from Chardonnay, Glera, Microvine, Pinot Noir, Sangiovese cultivars and two rootstocks, 110 Richter and SO4, cultured and maintained
in vitro up to embryo development and then used to perform Agrobacterium tumefaciens GV3101 mediated transformation
A Full Computerized Workflow for Planning Surgically Assisted Rapid Palatal Expansion and Orthognathic Surgery in a Skeletal Class III Patient
: In the present case report, we present and discuss the digital workflow involved in the orthodontic/orthognathic combined treatment of a skeletal malocclusion correction in a 17-year-old male patient affected by a skeletal class III, facial asymmetry, sagittal and transversal deficiency of the medium third of the skull, dental crowding, and bilateral cross-bite. The first stage of the treatment involved surgically assisted rapid palatal expansion and occlusal decompensation, using fixed self-ligating appliance. An orthodontic software package (i.e., Dolphin 3D Surgery module) was used to perform virtual treatment objective evaluation by integrating data from cone beam computer tomography acquisition, intraoral scan, and extraoral photographs. The software allowed a comprehensive evaluation of skeletal, dento-alveolar, and soft-tissue disharmonies, qualitative and quantitative simulation of surgical procedure according to skeletal and aesthetic objectives, and, consequently, the treatment of the malocclusion. Using a specific function of the software, the surgical splint was designed according to the pre-programmed skeletal movements, and subsequently, the physical splint was generated with a three-dimensional (3D) printing technology. Once a proper occlusal decompensation was reached, a Le Fort I osteotomy of the maxilla and a bilateral sagittal surgical osteotomy of the mandible were executed to restore proper skeletal relations. The whole treatment time was 8 months. The orthodontic/orthognathic combined treatment allowed to correct the skeletal and the dental imbalance, as well as the improvement of facial aesthetics. Accordingly, the treatment objectives planned in the virtual environment were achieved. Virtual planning offers new possibilities for visualizing the relationship between dental arches and surrounding bone and soft structures in a single virtual 3D model, allowing the specialists to simulate different surgical and orthodontic procedures to achieve the best possible result for the patient and providing an accurate and predictable outcome in the treatment of challenging malocclusions
A New Methodology for the Digital Planning of Micro-Implant-Supported Maxillary Skeletal Expansion
Introduction: Miniscrew-assisted rapid palatal expansion (MARPE) appliances utilize the skeletal anchorage to expand the maxilla. One type of MARPE device is the Maxillary Skeletal Expander (MSE), which presents four micro-implants with bicortical engagement of the palatal vault and nasal floor. MSE positioning is traditionally planned using dental stone models and 2D headfilms. This approach presents some critical issues, such as the inability to identify the MSE position relative to skeletal structures, and the potential risk of damaging anatomical structures. Methods: A novel methodology has been developed to plan MSE position using the digital model of dental arches and cone-beam computed tomography (CBCT). A virtual model of MSE appliance with the four micro-implants was created. After virtual planning, a positioning guide is virtually designed, 3D printed, and utilized to model and weld the MSE supporting arms to the molar bands. The expansion device is then cemented in the patient oral cavity and micro-implants inserted. A clinical case of a 12.9-year-old female patient presenting a Class III malocclusion with transverse and sagittal maxillary deficiency is reported. Results: The midpalatal suture was opened with a split of 3.06 mm and 2.8 mm at the anterior and posterior nasal spine, respectively. After facemask therapy, the sagittal skeletal relationship was improved, as shown by the increase in ANB, A-Na perpendicular and Wits cephalometric parameters, and the mandibular plane rotated 1.6\ub0 clockwise. Conclusion: The proposed digital methodology represents an advancement in the planning of MSE positioning, compared to the traditional approach. By evaluating the bone morphol-ogy of the palate and midface on patient CBCT, the placement of MSE is improved regarding the biomechanics of maxillary expansion and the bone thickness at micro-implants insertion sites. In the present case report, the digital planning was associated with a positive outcome of maxillary expansion and protraction in safety conditions
Age-Related Impairment in Insulin Release The Essential Role of beta(2)-Adrenergic Receptor
In this study, we investigated the significance of β(2)-adrenergic receptor (β(2)AR) in age-related impaired insulin secretion and glucose homeostasis. We characterized the metabolic phenotype of β(2)AR-null C57Bl/6N mice (β(2)AR(-/-)) by performing in vivo and ex vivo experiments. In vitro assays in cultured INS-1E β-cells were carried out in order to clarify the mechanism by which β(2)AR deficiency affects glucose metabolism. Adult β(2)AR(-/-) mice featured glucose intolerance, and pancreatic islets isolated from these animals displayed impaired glucose-induced insulin release, accompanied by reduced expression of peroxisome proliferator-activated receptor (PPAR)γ, pancreatic duodenal homeobox-1 (PDX-1), and GLUT2. Adenovirus-mediated gene transfer of human β(2)AR rescued these defects. Consistent effects were evoked in vitro both upon β(2)AR knockdown and pharmacologic treatment. Interestingly, with aging, wild-type (β(2)AR(+/+)) littermates developed impaired insulin secretion and glucose tolerance. Moreover, islets from 20-month-old β(2)AR(+/+) mice exhibited reduced density of β(2)AR compared with those from younger animals, paralleled by decreased levels of PPARγ, PDX-1, and GLUT2. Overexpression of β(2)AR in aged mice rescued glucose intolerance and insulin release both in vivo and ex vivo, restoring PPARγ/PDX-1/GLUT2 levels. Our data indicate that reduced β(2)AR expression contributes to the age-related decline of glucose tolerance in mice
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