Southern right whales show no behavioral response to low noise levels from a nearby unmanned aerial vehicle

Unmanned aerial vehicles (UAVs) are increasingly used for wildlife research and monitoring, but little information exists on their potential effect on marine mammals. We assessed the effects of a UAV on the behavior of southern right whales (Eubalaena australis) in Australia. Focal follows of ten right whale mother-calf pairs were conducted using a theodolite. Control data were recorded for 30 min, and then a DJI Inspire 1 Pro was flown above the whales for 10 min at 5 m altitude. Potential changes to horizontal behavior (swim speed and turning angle) and surfacing pattern (interbreath intervals) were investigated by comparing mother-calf behavior before and during UAV approaches. Changes in respiration rate were used to quantify energetic effects. We also explored acoustic cue perceptibility of the UAV at 5, 10, and 30 m altitude, by measuring the received UAV underwater noise level on whales equipped with acoustic tags (DTAGs). The received noise levels were 86.0 ± 3.9 dB re 1 μPa, while the measured ambient noise was 80.7 ± 7.3 dB re 1 μPa in the same frequency band (100–1,500 Hz). No behavioral response to the UAV was observed. This provides support for UAVs as a noninvasive tool to study baleen whale behavior and ecophysiology.     

Programmable assembly of 2D crystalline protein arrays into covalently stacked 3D bionanomaterials

Rational embellishment of self-assembling two-dimensional (2D) proteins make it possible to build 3D nanomaterials with novel catalytic, optoelectronic and mechanical properties. However, introducing multiple sites of embellishment into 2D protein arrays without affecting the self-assembly is challenging, limiting the ability to program in additional functionality and new 3D configurations. Here we introduce two orthogonal covalent linkages at multiple sites in a 2D crystalline-forming protein without affecting its self-assembly. We first engineered the surface-layer protein SbsB from Geobacillus stearothermophilus pV72/p2 to display isopeptide bond-forming protein conjugation pairs, SpyTag or SnoopTag, at four positions spaced 5.7-10.5 nm apart laterally and 3 nm axially. The C-terminal and two newly-identified locations within SbsB monomer accommodated the short SpyTag or SnoopTag peptide tags without affecting the 2D lattice structure. Introducing tags at distinct locations enabled orthogonal and covalent binding of SpyCatcher- or SnoopCatcher-protein fusions to micron-sized 2D nanosheets. By introducing different types of bifunctional cross-linkers, the dual-functionalized nanosheets were programmed to self-assemble into different 3D stacks, all of which retain their nanoscale order. Thus, our work creates a modular protein platform that is easy to program to create dual-functionalized 2D and lamellar 3D nanomaterials with new catalytic, optoelectronic, and mechanical properties.     

The potential of annexin-labelling for the diagnosis and follow-up of glaucoma

Glaucoma is one of the leading causes of blindness in developed countries and is mainly attributable to the apoptosis of retinal ganglion cells (RGCs). Although several diagnostic tools have been developed to detect and monitor this disease, none has the requisite sensitivity to identify it at a preclinical stage or to perceive small changes in retinal health over short periods. Specifically, irreversible visual changes occur before neuronal damage is discovered. The most widely accepted in vitro assay for apoptotic cells involves the use of fluorescent annexin A5. The radiolabelling of this marker makes it possible to assess, in vivo and non-invasively, various diseases in which the apoptotic process is pivotal, such as myocardial infarction or tumour response to chemotherapy. Recently, a new technique has been developed to visualise directly individual RGCs undergoing apoptosis in the living eye. This DARC (detection of apoptosing retinal cells) technology uses fluorescently labelled annexin A5 to bind apoptosing retinal neurons and confocal scanning laser ophthalmoscopy to detect the marked dying cells. Based on experimental models, DARC has been suggested to offer a direct and quantitative assessment of the retinal condition of patients. A Phase I clinical trial in glaucoma patients is scheduled to start shortly. This technology has the potential to pre-empt the diagnosis of glaucoma prior to visual deterioration, to provide an accurate numeric evaluation highlighting even small retinal changes and to allow the rapid judgement of the efficacy of both current and new therapeutic strategies.     

Tight intramolecular regulation of the human Upf1 helicase by its N- and C-terminal domains

The RNA helicase Upf1 is a multifaceted eukaryotic enzyme involved in DNA replication, telomere metabolism and several mRNA degradation pathways. Upf1 plays a central role in nonsense-mediated mRNA decay (NMD), a surveillance process in which it links premature translation termination to mRNA degradation with its conserved partners Upf2 and Upf3. In human, both the ATP-dependent RNA helicase activity and the phosphorylation of Upf1 are essential for NMD. Upf1 activation occurs when Upf2 binds its N-terminal domain, switching the enzyme to the active form. Here, we uncovered that the C-terminal domain of Upf1, conserved in higher eukaryotes and containing several essential phosphorylation sites, also inhibits the flanking helicase domain. With different biochemical approaches we show that this domain, named SQ, directly interacts with the helicase domain to impede ATP hydrolysis and RNA unwinding. The phosphorylation sites in the distal half of the SQ domain are not directly involved in this inhibition. Therefore, in the absence of multiple binding partners, Upf1 is securely maintained in an inactive state by two intramolecular inhibition mechanisms. This study underlines the tight and intricate regulation pathways required to activate multifunctional RNA helicases like Upf1.     

Reproductive system morphology of Lightiella magdalenina (Crustacea,Cephalocarida): functional and adaptive implications

The reproductive systems of adults and larvae of Lightiella magdalenina were examined. Lightiella magdalenina, similar to the best-known cephalocarida species Hutchinsoniella macracantha, is a simultaneous hermaphrodite. Although the morphology of their reproductive system is similar, L. magdalenina differs from H. macracantha in exhibiting reduced fecundity: it lays one egg, not two, per reproductive event. This is due to asynchronous development of the oocytes inside the paired female reproductive structures, which determines the maturation of a single egg at a time. The reduced fecundity of L. magdalenina could be offset by the precocious release of oocytes from the germarium, which begins the vitellogenetic process during the last larval stages. Due to this process, after their last moult, reproductive adults can have a large number of advanced vitellogenic oocytes, reducing the time required for their maturation. A possible adaptive relationship between the halved fecundity with pre- and post-hatching parental care is discussed.     

Inorganic phosphate enhances sensitivity of human osteosarcoma U2OS cells to doxorubicin via a p53‐dependent pathway

Osteosarcoma is the most common malignant primary bone tumor in children and adolescents. The clinical outcome for osteosarcoma remains discouraging despite aggressive surgery and intensive radiotherapy and chemotherapy regimens. Thus, novel therapeutic approaches are needed. Previously, we have shown that inorganic phosphate (Pi) inhibits proliferation and aggressiveness of human osteosarcoma U2OS cells identifying adenylate cyclase, beta3 integrin, Rap1, ERK1/2 as proteins whose expression and function are relevantly affected in response to Pi. In this study, we investigated whether Pi could affect chemosensitivity of osteosarcoma cells and the underlying molecular mechanisms. Here, we report that Pi inhibits proliferation of p53‐wild type U2OS cells (and not of p53‐null Saos and p53‐mutant MG63 cells) by slowing‐down cell cycle progression, without apoptosis occurrence. Interestingly, we found that Pi strongly enhances doxorubicin‐induced cytotoxicity in U2OS, and not in Saos and MG63 cells, by apoptosis induction, as revealed by a marked increase of sub‐G1 population, Bcl‐2 downregulation, caspase‐3 activation, and PARP cleavage. Remarkably, Pi/doxorubicin combination‐induced cytotoxicity was accompanied by an increase of p53 protein levels and of p53 target genes mdm2, p21 and Bax, and was significantly reduced by the p53 inhibitor pifithrine‐alpha. Moreover, the doxorubicin‐induced cytotoxicity was associated with ERK1/2 pathway inhibition in response to Pi. Altogether, our data enforce the evidence of Pi as a novel signaling molecule capable of inhibiting ERK pathway and inducing sensitization to doxorubicin of osteosarcoma cells by p53‐dependent apoptosis, implying that targeting Pi levels might represent a rational strategy for improving osteosarcoma therapy. J. Cell. Physiol. 228: 198–206, 2013. © 2012 Wiley Periodicals, Inc.     

Rotavirus Viroplasm Proteins Interact with the Cellular SUMOylation System: Implications for Viroplasm-Like Structure Formation

Posttranslational modification by SUMO provides functional flexibility to target proteins. Viruses interact extensively with the cellular SUMO modification system in order to improve their replication, and there are numerous examples of viral proteins that are SUMOylated. However, thus far the relevance of SUMOylation for rotavirus replication remains unexplored. In this study, we report that SUMOylation positively regulates rotavirus replication and viral protein production. We show that SUMO can be covalently conjugated to the viroplasm proteins VP1, VP2, NSP2, VP6, and NSP5. In addition, VP1, VP2, and NSP2 can also interact with SUMO in a noncovalent manner. We observed that an NSP5 SUMOylation mutant protein retains most of its activities, such as its interaction with VP1 and NSP2, the formation of viroplasm-like structures after the coexpression with NSP2, and the ability to complement in trans the lack of NSP5 in infected cells. However, this mutant is characterized by a high degree of phosphorylation and is impaired in the formation of viroplasm-like structures when coexpressed with VP2. These results reveal for the first time a positive role for SUMO modification in rotavirus replication, describe the SUMOylation of several viroplasm resident rotavirus proteins, and demonstrate a requirement for NSP5 SUMOylation in the production of viroplasm-like structures.