Hybrid millidecade spectra: A practical format for exchange of long-term ambient sound data.

This Letter proposes a frequency scaling for processing, storing, and sharing high-bandwidth, passive acoustic spectral data that optimizes data volume while maintaining reasonable data resolution. The format is a hybrid that uses 1 Hz resolution up to 455 Hz and millidecade frequency bands above 455 Hz. This hybrid is appropriate for many types of soundscape analysis, including detecting different types of soundscapes and regulatory applications like computing weighted sound exposure levels. Hybrid millidecade files are compressed compared to the 1 Hz equivalent such that one research center could feasibly store data from hundreds of projects for sharing among researchers globally.

Automatic data selection for validation: A method to determine cetacean occurrence in large acoustic data sets.

Passive acoustic monitoring (PAM) can inform wildlife management by providing information on the distribution of cetaceans. This paper presents an automatic data selection for validation (ADSV) method to effectively identify all species acoustically present in large PAM data sets. The ADSV method involves the application of automated detectors, the automated selection of a portion of data for manual review, and the evaluation/optimization of automated detectors. Using an exemplar data set, results from the ADSV method were compared to a more intensive systematic manual review method. The two methods were found to have similar species occurrence results (hourly occurrence matching 73%-100%).

Erratum: Hybrid millidecade spectra: A practical format for exchange of long-term ambient sound data [JASA Express Lett. 1(1), 011203 (2021)].

In the original paper [JASA Express Lett. 1(1), 011203 (2021)], a method for processing, storing, and sharing high-bandwidth, passive acoustic spectral data that optimizes data volume while maintaining reasonable data resolution was proposed. The format was a hybrid that uses 1-Hz resolution up to 455 Hz and millidecade frequency bands above 455 Hz. The choice of 455 Hz was based on a method of computing the edge frequencies of millidecade bands that is not compatible with summing millidecades to decidecades. This has been corrected. The new transition frequency is the first frequency with a millidecade with greater than 1 Hz, 435 Hz.

Near real-time marine mammal monitoring from gliders: Practical challenges, system development, and management implications.

In 2017, an endangered North Atlantic right whale mortality event in the Gulf of St. Lawrence, Canada, triggered the implementation of dynamic mitigation measures that required real-time information on whale distribution. Underwater glider-based acoustic monitoring offers a possible solution for collecting near real-time information but has many practical challenges including self-noise, energy restrictions, and computing capacity, as well as limited glider-to-shore data transfer bandwidth. This paper describes the development of a near real-time baleen whale acoustic monitoring glider system and its evaluation in the Gulf of St. Lawrence in 2018. Development focused on identifying and prioritizing important acoustic events and on sending contextual information to shore for human validation. The system performance was evaluated post-retrieval, then the trial was simulated using optimized parameters. Trial simulation evaluation revealed that the validated detections of right, fin, and blue whales produced by the system were all correct; the proportion of species occurrence missed varied depending on the timeframe considered. Glider-based near real-time monitoring can be an effective and reliable technique to inform dynamic mitigation strategies for species such as the North Atlantic right whale.

Biotherapies of neuromuscular disorders.

This review focuses on the most recent data on biotherapeutic approaches, using DNA, RNA, recombinant proteins, or cells as therapeutic tools or targets for the treatment of neuromuscular diseases. Many of these novel technologies have now reached the clinical stage and have or are about to move to the market. Others, like genome editing are still in an early stage but hold great promise.

Autoantibodies against galectin-2 peptides as biomarkers for the antiphospholipid syndrome.

Autoantibodies against opsonins of dying and dead cells mediate Fcγ receptor-dependent phagocytosis of autologous apoptotic and necrotic cells and hereby tend to elicit inflammation instead of silent clearance. We analysed sera of patients with chronic autoimmune diseases for the occurrence of IgG autoantibodies recognizing galectins. These pluripotent effectors can also bind to apoptotic or necrotic cells. Patients with antiphospholipid syndrome (APS; n = 104) and systemic lupus erythematosus (SLE; n = 62) were examined, healthy donors (n = 31) served as controls. Selected peptides of galectin (Gal)-2 were employed for peptide-based ELISAs. Levels of anti-Gal-2(PEP)-IgG were significantly increased in SLE and APS when compared with controls. In addition, patients with APS showed significantly higher levels of anti-Gal-2(PEP)-IgG compared with patients with SLE. Anti-Gal-2(PEP)-IgG may, therefore, be considered novel biomarkers for APS.

HIV-1 Tat protein directly induces mitochondrial membrane permeabilization and inactivates cytochrome c oxidase.

The Trans-activator protein (Tat) of human immunodeficiency virus (HIV) is a pleiotropic protein involved in different aspects of AIDS pathogenesis. As a number of viral proteins Tat is suspected to disturb mitochondrial function. We prepared pure synthetic full-length Tat by native chemical ligation (NCL), and Tat peptides, to evaluate their direct effects on isolated mitochondria. Submicromolar doses of synthetic Tat cause a rapid dissipation of the mitochondrial transmembrane potential (ΔΨ(m)) as well as cytochrome c release in mitochondria isolated from mouse liver, heart, and brain. Accordingly, Tat decreases substrate oxidation by mitochondria isolated from these tissues, with oxygen uptake being initially restored by adding cytochrome c. The anion-channel inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) protects isolated mitochondria against Tat-induced mitochondrial membrane permeabilization (MMP), whereas ruthenium red, a ryanodine receptor blocker, does not. Pharmacologic inhibitors of the permeability transition pore, Bax/Bak inhibitors, and recombinant Bcl-2 and Bcl-XL proteins do not reduce Tat-induced MMP. We finally observed that Tat inhibits cytochrome c oxidase (COX) activity in disrupted mitochondria isolated from liver, heart, and brain of both mouse and human samples, making it the first described viral protein to be a potential COX inhibitor.

HrpZ harpins from different Pseudomonas syringae pathovars differ in molecular interactions and in induction of anion channel responses in Arabidopsis thaliana suspension cells.

HrpZ, a type three secretion system helper protein from the plant-pathogen Pseudomonas syringae, can be recognized by many plants as a defence elicitor. Responses of Arabidopsis thaliana suspension cells to different HrpZ variants were studied by electrophysiological methods and cell death assay. Purified HrpZ originating from a compatible pathogen P. syringae pv. tomato DC3000 (HrpZ(Pto)) and incompatible P. syringae pv. phaseolicola (HrpZ(Pph)) both promoted Arabidopsis cell death. As an early response, both HrpZ variants induced an increase in time dependent K(+) outward rectifying current. In contrast, the effects of HrpZ proteins on anion currents were different: HrpZ(Pph) had no effect, and HrpZ(Pto) induced an anion current increase. This suggests that the observed responses of the K(+) channels and anion channels resulted from different and separable interactions and that the interaction implied in anion current modulation is host-specific. HrpZ(Pto) and HrpZ(Pph) also had a different sequence preference in phage display screen for peptide-binding. These peptides presumably represent a part of a putative target protein in the host, and HrpZ proteins of different P. syringae pathovars might have different binding specificities to match the allelic variation between plant species. Supporting the idea that the peptide-binding region of HrpZ is important for interactions with host cell components, we found that a mutation in that region changed the anion channel response of Arabidopsis cells.

An early Ca2+ influx is a prerequisite to thaxtomin A-induced cell death in Arabidopsis thaliana cells.

The pathogenicity of various Streptomyces scabies isolates involved in potato scab disease was correlated with the production of thaxtomin A. Since calcium is known as an essential second messenger associated with pathogen-induced plant responses and cell death, it was investigated whether thaxtomin A could induce a Ca2+ influx related to cell death and to other putative plant responses using Arabidopsis thaliana suspension cells, which is a convenient model to study plant-microbe interactions. A. thaliana cells were treated with micromolar concentrations of thaxtomin A. Cell death was quantified and ion flux variations were analysed from electrophysiological measurements with the apoaequorin Ca2+ reporter protein and by external pH measurement. Involvement of anion and calcium channels in signal transduction leading to programmed cell death was determined by using specific inhibitors. These data suggest that this toxin induces a rapid Ca2+ influx and cell death in A. thaliana cell suspensions. Moreover, these data provide strong evidence that the Ca2+ influx induced by thaxtomin A is necessary to achieve this cell death and is a prerequisite to early thaxtomin A-induced responses: anion current increase, alkalization of the external medium, and the expression of PAL1 coding for a key enzyme of the phenylpropanoid pathway.

Targeted Vpr-derived peptides reach mitochondria to induce apoptosis of alphaVbeta3-expressing endothelial cells.

The HIV-1 encoded apoptogenic protein Vpr induces mitochondrial membrane permeabilization (MMP) via interactions with the voltage-dependent anion channel (VDAC) and the adenine nucleotide translocator (ANT). We have designed a peptide, TEAM-VP, composed of two functional domains, one a tumor blood vessel RGD-like 'homing' motif and the other an MMP-inducing sequence derived from Vpr. When added to isolated mitochondria, TEAM-VP interacts with ANT and VDAC, reduces oxygen consumption and overcomes Bcl-2 protection to cause inner and outer MMP. TEAM-VP specifically recognizes cell-surface expressed alpha(V)beta(3) integrins, internalizes, temporarily localizes to lysosomes and progressively co-distributes with the mitochondrial compartment with no sign of lysosomal membrane permeabilization. Finally TEAM-VP reaches mitochondria of angiogenic endothelial cells to induce mitochondrial fission, dissipation of the mitochondrial transmembrane potential (DeltaPsi(m)), cytochrome c release and apoptosis hallmarks. Hence, this chimeric peptide constitutes the first example of a virus-derived mitochondriotoxic compound as a candidate to kill selectively tumor neo-endothelia.

Early physiological responses of Arabidopsis thaliana cells to fusaric acid: toxic and signalling effects.

Fusaric acid (FA) is a toxin produced by Fusarium species. Most studies on FA have reported toxic effects (for example, alteration of cell growth, mitochondrial activity and membrane permeability) at concentrations greater than 10(-5) m. FA participates in fungal pathogenicity by decreasing plant cell viability. However, FA is also produced by nonpathogenic Fusarii, potential biocontrol agents of vascular wilt fusaria. The aim of this study was to determine whether FA, at nontoxic concentrations, could induce plant defence responses. Nontoxic concentrations of FA were determined from cell-growth and O2-uptake measurements on suspensions of Arabidopsis thaliana cells. Ion flux variations were analysed from electrophysiological and pH measurements. H2O2 and cytosolic calcium were quantified by luminescence techniques. FA at nontoxic concentrations (i.e. below 10(-6) m) was able to induce the synthesis of phytoalexin, a classic delayed plant response to pathogen. FA could also induce rapid responses putatively involved in signal transduction, such as the production of reactive oxygen species, and an increase in cytosolic calcium and ion channel current modulations. FA can thus act as an elicitor at nanomolar concentrations.

Variations in the microcystin production of Planktothrix rubescens (cyanobacteria) assessed from a four-year survey of Lac du Bourget (France) and from laboratory experiments.

Between 1999 and 2002, a routine survey of water quality in the Lac du Bourget was performed to study the dynamics and microcystin (MC) production of Planktothrix rubescens. Using liquid chromatography coupled to diode array detection and mass spectrometry, we found that two main variants ([D-Asp3] and [D-Asp3, Dhb7] microcystin-RR) were produced. The proportion of these two variants was not influenced by the depth or season of sampling. Expressed in microcystin-LR equivalents, high microcystin concentrations were recorded from August to December each year, reaching values of up to 6.7 microg L-1. A significant correlation was found between the microcystin cell content and the cell densities of P. rubescens. Cellular quotas of microcystins ranged from 0.1 to 0.3 pg cell-1. Simultaneously, laboratory experiments were performed on a strain of P. rubescens isolated from the lake to assess the potential impact of various P-PO4 (3-) concentrations on intra- and extracellular microcystin production. Unlike natural populations, this strain only produced [D-Asp3] MC-RR. The intracellular microcystin content was similarly correlated to the cell density, but the cellular quota was slightly higher (0.3-0.7 pg cell-1) than in the natural population. Again, as in the natural population, a linear relationship was found between growth rate and microcystin production rate. These findings support the hypothesis that environmental factors, such as phosphate concentrations, have no direct impact on microcystin production by P. rubescens, but act indirectly by affecting growth rate.

The N-terminus of HIV-1 Tat protein is essential for Tat-TAR RNA interaction.

The human HIV transactivator protein Tat is essential for efficient viral transcription that occurs by a complex mechanism involving interaction of Tat with the TAR RNA element. This interaction appears to require the mediation of a cellular protein, cyclin T1. However, the possibility that Tat and TAR associate in a binary Tat-TAR complex has been little investigated. Using a chemically synthesized active Tat protein, the kinetic and equilibrium parameters of its interaction with TAR were determined by surface plasmon resonance technology. Independently of partner and method of immobilization onto the sensor chip, the association (k(a) = 5-9 x 10(5) M(-1) s(-1)) and dissociation rate constants (k(d) = 1.7-4.3 x 10(-3) s(-1)) yielded similar equilibrium dissociation constants (K(d) = 2-8 nM). A truncated peptide encompassing residues 30-86 of Tat did not bind to TAR at all. We conclude that Tat can form a high-affinity complex with TAR in the absence of cyclin T1 and that the N-terminal domain of Tat is essential for this interaction, suggesting a conformational link between this domain and the basic domain of Tat. These results are important in our quest for developing therapeutic compounds that impair viral replication.

Active immunization against murine TNFalpha peptides in mice: generation of endogenous antibodies cross-reacting with the native cytokine and in vivo protection.

New lines of treatment targeting cytokines have been successfully developed recently and are now widely used in therapy. They are based on passive administration of cytokine inhibitors either soluble receptors or mAbs and the major example is TNFalpha in rheumatoid arthritis (RA). Since a few years, our group has developed a novel alternative approach targeting cytokines by using active immunization against biologically inactive but immunogenic cytokine derivatives. In the present work, we present a new aspect of this research, based on immunization against specific cytokine peptides chosen by molecular modelling. We could elicit a significant humoral response against four TNFalpha peptides by active immunization, and show that the Abs generated cross-reacted with the native cytokine with good titers as determined by ELISA. Interestingly, during coimmunization experiments with couples of peptides, one showed a clear immunodominant effect over the other. Overall, we could not show the neutralization of TNFalpha biological activity in vitro by the immunized sera, but it seems that it is not a prerequisite to observe clinical efficacy. Indeed, using the LPS/galactosamine-induced shock, we could demonstrate that one of the four peptides tested conferred a clinical protection. These results validate the feasibility and efficacy of active immunization against cytokine peptides, and confirm that active immunization against cytokines could represent in the future an alternative to passive immunization in many diseases.

Synthesis of enantiopure 4-hydroxypipecolate and 4-hydroxylysine derivatives from a common 4,6-dioxopiperidinecarboxylate precursor.

tert-Butyl 2-substituted 4,6-dioxo-1-piperidinecarboxylates 4 have been prepared in good yield starting from Boc-Asp-O(t)Bu and other beta-amino acids. By analogy with chiral tetramic acids, their reduction by NaBH(4) in CH(2)Cl(2)/AcOH afforded the corresponding cis-4-hydroxy delta-lactams in good yield and stereoselectivity (68-98% de). In the absence of the A(1,3) strain (reduction of 6-substituted 2,4-dioxo-1-piperidines 7), the cis-4-hydroxy isomer was still obtained as the major product but the de values were consistently lower. 4-Hydroxy-6-oxo-1,2-piperidinedicarboxylate 2a, readily accessible from Boc-Asp-O(t)Bu (three steps, 63% overall yield), has proven to be an excellent building block for the synthesis of cis- and trans-4-hydroxypipecolates 17 and 24 (52 and 36% overall yield, respectively) and for the synthesis of a protected 4-hydroxylysine derivative 29 (41% overall yield).

Characterization of zebrafish Cx43.4 connexin and its channels.

Connexins (Cx) form intercellular junctional channels which are responsible for metabolic and electrical coupling. We report here on the biochemical and immunohistochemical characterization of zebrafish connexin zfCx43.4, an orthologue of mammalian and avian Cx45, and the electrophysiological properties of junctional channels formed by this protein. The investigations were performed on transfected COS-7 cells or HeLa cells. Using site-directed antibodies, zfCx43.4 cDNA (GenBank accession no. X96712) was demonstrated to code for a protein with a M(r) of 45 000. In transfected cells, zfCx43.4 was localized in cell-cell contact areas as expected for a gap junction protein. zfCx43.4 channels were shown to transfer Lucifer Yellow. The multichannel currents were sensitive to the transjunctional voltage (V(j)). Their properties were consistent with a two-state model and yielded the following Boltzmann parameters for negative/positive V(j): V(j,0) = -38.4/41.9 mV; g(j,min) = 0.19/0.18; z = 2.6/2.3. These parameters deviate somewhat from those of zfCx43.4 channels expressed in Xenopus oocytes and from those of Cx45, an orthologue of zfCx43.4, expressed in mammalian cells or Xenopus oocytes. Conceivably, the subtle differences may reflect differences in experimental methods and/or in the expression system. The single channel currents yielded two prominent levels attributable to a main conductance state (gamma(j,main) = 33.2 +/- 1.5 pS) and a residual conductance state (gamma(j,residual) = 11.9 +/- 0.6 pS).

Toxicological comparison of diverse Cylindrospermopsis raciborskii strains: evidence of liver damage caused by a French C raciborskii strain.

The freshwater cyanobacterium Cylindrospermopsis raciborskii is known to produce toxic effects in several countries. Acute and chronic exposures to C. raciborskii in Australia have been linked to liver damage (hepatotoxicity) with concomitant effects on the kidneys, adrenal glands, small intestine, lungs, thymus, and heart. The alkaloid cylindrospermopsin, which produces these toxic effects, is thought to be a potent inhibitor of protein synthesis. C. raciborskii strains producing cylindrospermopsin or analogue alkaloids have also been reported in Florida, USA, and Thailand. Brazilian isolates of C. raciborskii are also toxic but act by a different mechanism, causing acute death in mice with neurotoxic symptoms similar to those induced by the saxitoxins. In this article we compare the toxicity in the mouse of a C. raciborskii French strain with C. raciborskii strains from various other sources (Australia, Brazil, Mexico, and Hungary). We tested the toxicity of cell extracts by a mouse bioassay. Acute, fatal neurotoxicity was produced by the Brazilian strain, which was confirmed by liquid chromatography with fluorescence detection of the cell extracts, which revealed the presence of saxitoxin, neosaxitoxin, and decarbamoylsaxitoxin, along with two unidentified compounds. Acute hepatotoxicity with severe liver, kidney, and thymus damage was observed with the Australian cylindrospermopsin-producing strain. The Mexican and Hungarian strains were not found to be toxic to mice in our experimental conditions. No animals died after exposure to the extracts of the French C. raciborskii strain. Histological examination of the liver revealed moderate, multifocal necrosis characterized by small areas of hepatocellular necrosis, combined with disorganization of the parenchyma and congestion of the inner sinusoid. These symptoms and lesions resembled those induced by cylindrospermopsin, but the chemical analysis performed by liquid chromatography coupled with either a diode array detector or a mass spectrometer demonstrated that this toxin was not present in our culture extract.

Immunity under the skin: potential application for topical delivery of vaccines.

With the technological advances in biomedical sciences and the better understanding of how the immune system works, new immunisation strategies and vaccine delivery options, such sprays, patches, and edible formulations have been developed. This has opened up the possibility of administering vaccines without the use of needles and syringes. Already topical immunisation is a reality and it has the potential to make vaccine delivery more equitable, safer, and efficient. Furthermore, it would increase the rate of vaccine compliance and greatly facilitate the successful implementation of worldwide mass vaccination campaigns against infectious diseases. This review gives a brief account of the latest developments of application of candidate vaccine antigens onto bare skin and describes some of our recent observations using peptide and glycoconjugate vaccines as immunogens.