Correction to: Inhibition of cathepsin B by caspase-3 inhibitors blocks programmed cell death in Arabidopsis.

We thank D Nicholson for initial advice on caspase activity purification and B Turk for advice on recombinant cathepsin B. We thank N Atanasova for cell death assays. The Bioimaging Facility microscopes used in this study were purchased with grants from BBSRC, Wellcome Trust and the University of Manchester Strategic Fund. Special thanks go to D Knight in the Faculty Biomolecular Analysis facility. We thank P Birch and M Kim for improving the manuscript. The project was partially funded by BBSRC Grants 34/P14516, BB/K009478/1 and China National High-Tech Research and Development Programme(863 programme)NO. 2015AA020903.

Inhibition of cathepsin B by caspase-3 inhibitors blocks programmed cell death in Arabidopsis.

Programmed cell death (PCD) is used by plants for development and survival to biotic and abiotic stresses. The role of caspases in PCD is well established in animal cells. Over the past 15 years, the importance of caspase-3-like enzymatic activity for plant PCD completion has been widely documented despite the absence of caspase orthologues. In particular, caspase-3 inhibitors blocked nearly all plant PCD tested. Here, we affinity-purified a plant caspase-3-like activity using a biotin-labelled caspase-3 inhibitor and identified Arabidopsis thaliana cathepsin B3 (AtCathB3) by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Consistent with this, recombinant AtCathB3 was found to have caspase-3-like activity and to be inhibited by caspase-3 inhibitors. AtCathepsin B triple-mutant lines showed reduced caspase-3-like enzymatic activity and reduced labelling with activity-based caspase-3 probes. Importantly, AtCathepsin B triple mutants showed a strong reduction in the PCD induced by ultraviolet (UV), oxidative stress (H2O2, methyl viologen) or endoplasmic reticulum stress. Our observations contribute to explain why caspase-3 inhibitors inhibit plant PCD and provide new tools to further plant PCD research. The fact that cathepsin B does regulate PCD in both animal and plant cells suggests that this protease may be part of an ancestral PCD pathway pre-existing the plant/animal divergence that needs further characterisation.

Booming dune instability.

Sand avalanches flowing down the leeward face of some desert dunes spontaneously produce a loud sound with a characteristic vibrato around a well-defined frequency, a phenomenon called the "song of dunes." Here, we show through theory that a homogenous granular surface flow is linearly unstable towards growing elastic waves when a localized shear band forms at the interface between the avalanche and the static part of the dune. We unravel the nature of the acoustic amplifying mechanism at the origin of this booming instability. The dispersion relation and the shape of the most unstable modes are computed and compared to field measurements.

Evidence of rayleigh-hertz surface waves and shear stiffness anomaly in granular media.

Using the nonlinear dependence of sound propagation speed with pressure, we evidence the anomalous elastic softness of a granular packing in the vicinity of the jamming transition. Under gravity and close to a free surface, the acoustic propagation is only possible through surface modes guided by the stiffness gradient. These Rayleigh-Hertz modes are evidenced in a controlled laboratory experiment. The shape and the dispersion relation of both transverse and sagittal modes are compared to the prediction of nonlinear elasticity including finite size effects. These results allow one to access the elastic properties of the packing under vanishing confining pressure.

Surface elastic waves in granular media under gravity and their relation to booming avalanches.

Due to the nonlinearity of Hertzian contacts, the speed of sound c in granular matter is expected to increase with pressure as P(1/6). A static layer of grains under gravity is thus stratified so that the bulk waves are refracted toward the surface. The reflection at the surface being total, there is a discrete number of modes (both in the sagittal plane and transverse to it) localized close to the free surface. The shape of these modes and the corresponding dispersion relation are investigated in the framework of an elastic description taking into account the main features of granular matter: Nonlinearity between stress and strain and the existence of a yield transition. We show in this context that the surface modes localized at the free surface exhibit a waveguide effect related to the nonlinear Hertz contact. Recent results about the song of dunes are reinterpreted in light of the theoretical results. The predicted propagation speed is compared with measurements performed in the field. Taking into account the finite depth effects, we show that the booming instability threshold can be explained quantitatively by a waveguide cutoff frequency below which no sound can propagate. Therefore, we propose another look at a recent controversy, confirming that the song of dunes can well originate from a coupling between avalanching grains and surface elastic waves once the specificity of surface waves (we baptized Rayleigh-Hertz) is correctly taken into account.

Use of perfluorochemical liquid allows earlier detection of gene expression and use of less vector in normal lung and enhances gene expression in acutely injured lung.

One of the obstacles to successful lung gene transfer is effective delivery of vector to lung, particularly injured or diseased lung. We have previously demonstrated that intratracheal instillation of perfluorochemical (PFC) liquids along with instillation of recombinant adenovirus and adeno-associated virus vectors, or with cationic liposome vectors, increased total lung gene expression and enhanced distribution of gene expression throughout the lung. To further explore the potential benefits of PFC liquid use, we evaluated the effect of PFC liquid instillation on several other aspects of adenovirus-mediated gene expression in lung. Use of PFC liquid resulted in earlier detection of gene expression and allowed the use of less vector to achieve expression comparable to that observed with the use of higher amounts of vector alone. Using PFC liquid also enhanced gene expression in a rodent model of acute lung injury. PFC liquid did cause a transient inflammation when instilled into normal lungs but did not cause any additional inflammation when instilled alone or with adenovirus vector into acutely injured lungs. Thus, PFC liquid may be a useful adjunct for clinical lung gene transfer, particularly for injured or diseased lungs.

Perfluorochemical liquid enhances adeno-associated virus-mediated transgene expression in lungs.

Use of adeno-associated virus (AAV) vectors for lung gene therapy is limited, in part, by low levels of AAV-mediated transgene expression in lungs. Generally, less than 1% of total airway and alveolar epithelial cells express transgene activity following vector administration. A means of improving AAV vector delivery could potentially enhance AAV-mediated gene expression in lungs. We have previously demonstrated that use of perfluorochemical (PFC) liquids improved overall levels of adenovirus vector-mediated gene expression as well as distribution of expression in lungs of spontaneously breathing rodents. To evaluate whether use of PFC liquids might similarly enhance AAV-mediated expression, spontaneously breathing rodents received intratracheal instillation of the AAV vectors CWRAP and ARAP4 (2-5 x 10(8) FFU/animal) with or without 10 cc/kg body wt PFC liquid (FC-75, ACROS). Animals were sacrificed 4 weeks later and lungs assessed for overall and in situ alkaline phosphatase (AP) expression. Animals receiving vector alone exhibited scattered sparse in situ activity, predominantly in alveolar epithelium. In contrast, animals receiving vector with FC-75 exhibited increased and more widespread AP expression as well as up to a 26-fold increase in AP activity. These results demonstrate that use of the PFC liquid FC-75 improves overall and in situ AAV-mediated gene expression in rodent lungs.

Compensating for sight loss with a guide dog.

Although medical advances occur daily, ophthalmic nurses face vision decrease or loss in their patients. Orientation and mobility training are offered by state agencies, helping the person find ways to adjust to living with sight loss. Whereas a white cane is the preferred mobility method of choice for some persons, more persons are discovering the advantages of a guide dog. This article will help ophthalmic nurses understand how a guide dog is produced and the uses of a guide dog. This knowledge is an option to increase mobility in newly blind patients.

RNA editing of a Drosophila sodium channel gene.

Extensive analysis of cDNAs from the para locus in D. melanogaster reveals posttranscriptional modifications indicative of adenosine-to-inosine RNA editing. Most of these edits occur in highly conserved regions of the Na+ channel, and they occur in distant relatives of D. melanogaster as well. Sequence comparison between species has identified putative cis-acting elements important for each RNA editing site. Double-stranded RNA secondary structures with striking similarity to known RNA editing sites were generated based on these data. In addition, the RNA editing sites appear to be developmentally regulated. We have cloned a potential RNA editase, DRED, with a high degree of homology to the mammalian RED1,2 genes. The DRED locus itself is highly regulated by transcription from alternative promoters and alternative splicings.

Control of in vitro somatic embryogenesis of the spindle tree (Euonymus europaeus L.) by the sugar type and the osmotic potential of the culture medium.

In vitro somatic embryogenesis was achieved from zygotic embryo explants of a woody angiosperm species, the spindle tree, cultivated on various culture media differing in their sugar type and concentration, or in the applied osmotic potential. The highest frequency of somatic embryogenesis was obtained with a 350 mM sucrose, or a 89 mM glucose concentration in the culture medium. Experiments with culture media differing only in osmotic potential indicated that a minimal threshold osmotic potential is required to stimulate the emergence of somatic embryos. Elevated concentrations of glucose have an inhibitory effect, independent of their osmotic effect, while elevated concentrations of sucrose mainly act osmotically, stimulating the emergence of numerous somatic embryos.

Somatic embryogenesis and plant regeneration in a woody species: the European Spindle Tree (Euonymus europaeus L.).

Somatic embryogenesis and subsequent plant regeneration of Euonymus europaeus L (European Spindle Tree) were obtained from square pieces of mature zygotic embryos with an intervening callus phase. Callus and somatic embryos were induced using a Murashige and Skoog's semi-solid basal medium supplemented with several combinations of auxins and cytokinins. The greatest number of somatic embryos was obtained with a continuous exposure to 22.8 µM indoleacetic acid and 0.046 µM kinetin. The frequency of somatic embryogenesis from zygotic embryos depends on the cold conservation time of seeds. The embryos frequently germinated on the same medium. Further development of somatic embryos into plantlets was achieved on a medium devoid of growth regulators.

Studies on surface properties of asbestos. II. Role of dimensional characteristics and surface properties of mineral fibers in the induction of pleural tumors.

In animal experiments, the probability that pleural tumors will develop after mineral fiber implantation is dependent upon the fiber's size. This was originally analyzed in relation to the number of injected fibers with specific dimensional characteristics and, more recently, in relation to average aspect ratio (average length/diameter ratio). New experimental data on various mineral fibers suggest that the carcinogenic potency of a solid particle depends on two parameters: the nature of the mineral and therefore the nature of active surface sites, and the aspect ratio of the particle. These two parameters can intervene in a mechanism of model reaction involving the basic properties of lateral faces of fibers.

Studies on surface properties of asbestos. I. Active sites on surface of chrysotile and amphiboles.

The study of the acid-base properties of asbestos reveals a striking analogy between amphiboles and chrysotile. The high sites' density with basic character, evidenced by use of various probe molecules, is very similar for the two asbestos types (chrysotile and crocidolite) and on the same order as the density encountered in some catalysts. Discussion of the surface structure reveals that it is the noncrypting lateral surfaces which possess an electron donor character while the surfaces of the extremities of the fibers with crypting character possess a null or very weakly positive charge.