Rapid resource depletion on coral reefs disrupts competitor recognition processes among butterflyfish species.

Avoiding costly fights can help conserve energy needed to survive rapid environmental change. Competitor recognition processes help resolve contests without escalating to attack, yet we have limited understanding of how they are affected by resource depletion and potential effects on species coexistence. Using a mass coral mortality event as a natural experiment and 3770 field observations of butterflyfish encounters, we test how rapid resource depletion could disrupt recognition processes in butterflyfishes. Following resource loss, heterospecifics approached each other more closely before initiating aggression, fewer contests were resolved by signalling, and the energy invested in attacks was greater. By contrast, behaviour towards conspecifics did not change. As predicted by theory, conspecifics approached one another more closely and were more consistent in attack intensity yet, contrary to expectations, resolution of contests via signalling was more common among heterospecifics. Phylogenetic relatedness or body size did not predict these outcomes. Our results suggest that competitor recognition processes for heterospecifics became less accurate after mass coral mortality, which we hypothesize is due to altered resource overlaps following dietary shifts. Our work implies that competitor recognition is common among heterospecifics, and disruption of this system could lead to suboptimal decision-making, exacerbating sublethal impacts of food scarcity.

Regulatory guidelines and preclinical tools to study the biodistribution of RNA therapeutics.

The success of the messenger RNA-based COVID-19 vaccines of Moderna and Pfizer/BioNTech marks the beginning of a new chapter in modern medicine. However, the rapid rise of mRNA therapeutics has resulted in a regulatory framework that is somewhat lagging. The current guidelines either do not apply, do not mention RNA therapeutics, or do not have widely accepted definitions. This review describes the guidelines for preclinical biodistribution studies of mRNA/siRNA therapeutics and highlights the relevant differences for mRNA vaccines. We also discuss the role of in vivo RNA imaging techniques and other assays to fulfill and/or complement the regulatory requirements. Specifically, quantitative whole-body autoradiography, microautoradiography, mass spectrometry-based assays, hybridization techniques (FISH, bDNA), PCR-based methods, in vivo fluorescence imaging, and in vivo bioluminescence imaging, are discussed. We conclude that this new and rapidly evolving class of medicines demands a multi-layered approach to fully understand its biodistribution and in vivo characteristics.

6th vital sign app: Testing validity and reliability for measuring gait speed.

BACKGROUND: Gait speed tests are useful predictors of different health outcomes in people. These tests can be administered by the convenience of one's smartphone. RESEARCH QUESTION: Is the 6th Vital Sign app valid and reliable for measuring gait speed? METHODS: The study used a prospective test-retest design. Fifteen college subjects were asked to walk at their normal pace for 2 min. Each subject performed two trials. Speed was recorded by the 6th Vital Sign app, Brower timing gates, and by hand-measurement of distance walked divided by the 2 min. Criterion validity was assessed by paired t-tests, Cohen's D effect sizes, and Pearson correlation tests. Inter-trial reliability within each device was assessed with Pearson correlation tests. RESULTS: Speed measured by the app was significantly lower than speed measured by gates (p = 0.004) and by hand-measurement (p = 0.009). The difference between gates and hand-measurement was not significant (p = 0.684). The speed measured by gates and hand-measurement were very highly correlated (r = 0.974), but speed measured by app was only moderately correlated with gates (r = 0.370) and hand-measurement (r = 0.365). The inter-trial reliability was fairly high with correlations r = 0.916, 0.944, and 0.941 when speed was measured by the app, gates, and hand-measurement, respectively. SIGNIFICANCE: The app tended to underestimate speed when compared to gate and hand-measurements. Therefore, we conclude that the 6th Vital Sign app is not valid for use for clinical diagnosis or prognosis.

Immunological and angiogenic markers during metronomic temozolomide and cyclophosphamide in canine cancer patients.

Metronomic chemotherapy stimulates the immune response via depletion of regulatory T cells (Tregs) and suppresses angiogenesis by modulating the secretion of thrombospondin-1 (TSP-1) and vascular endothelial growth factor (VEGF). In this study, blood was collected from 10 healthy dogs and from 30 canine cancer patients before and 2 and 4 weeks after treatment with metronomic temozolomide (6.6 mg m-2 ), cyclophosphamide (12.5 mg m-2 ) or cyclophosphamide and temozolomide. The percentage of circulating CD25+ Foxp3+ CD4+ Tregs and the plasma levels of TSP-1 and VEGF were measured. There was a significant difference in the percentage of Tregs between cancer patients and healthy dogs. A significant decrease in Tregs was noted in patients treated with metronomic cyclophosphamide and the combination. Treatment with temozolomide had no effect on the percentage of Tregs. TSP-1 and VEGF levels were, respectively, significantly lower and higher in cancer patients than in healthy dogs, but they were not influenced by any of the studied metronomic treatment regimens.

Intratumoural interleukin 12 gene therapy stimulates the immune system and decreases angiogenesis in dogs with spontaneous cancer.

Interleukin 12 (IL-12) is a powerful immunostimulatory cytokine with a strong antitumoural activity. In this work, the immunological, anti-angiogenic and clinical effects of three consecutive intratumoural IL-12 electrogene therapy (EGT) treatments were evaluated in nine dogs with spontaneous cancer. In all the dogs, tumour biopsies and blood samples were taken prior, during and after the intratumoural IL-12 EGT (on days 1, 8, 35 and 1, 3, 8, 15, 35, respectively). An initial decrease in immune cells was followed by an increase above baseline 1-3 weeks after treatment initiation. Interestingly, the decrease in peripheral leukocytes 2 days after the first intratumoural IL-12 EGT coincided with erythema and tumour swelling. Transient increases of IL-12 and interferon γ were measured in the serum and the tumour tissue, whereas IL-10 transiently increased only in the serum. The effect of intratumoural IL-12 EGT on the levels of IL-24 and vascular endothelial growth factor in the sera and tumour biopsies differed per dog. Via contrast-enhanced ultrasound (US) (on days 1, 8 and 35), we demonstrated that intratumoural IL-12 EGT resulted in a significant decrease of the relative blood volume and blood flow speed in the tumour compared with baseline. Metastases were present in two dogs. In one of these dogs, IL-12 EGT of the primary tumour caused a transient partial regression of the metastases, but not of the primary tumour. The second dog with metastases did not survive long enough to complete the entire treatment cycle. Despite encouraging immunostimulatory and anti-angiogenic effects after intratumoural IL-12 EGT, no clinically relevant outcomes were observed in this study, as persistent tumour regression could not be obtained. On the other hand, the laboratory and US results hold great promise for combinatorial strategies of intratumoural IL-12 EGT with conventional antitumour (immuno)therapies.

In vitro exploration of a myeloid-derived suppressor cell line as vehicle for cancer gene therapy.

Recent research indicates that cell-mediated gene therapy can be an interesting method to obtain intratumoral expression of therapeutic proteins. This paper explores the possibility of using transfected myeloid-derived suppressor cells (MDSCs), derived from a murine cell line, as cellular vehicles for transporting plasmid DNA (pDNA) encoding interleukin-12 (IL-12) to tumors. Transfecting these cells via electroporation caused massive cell death. This was not due to electroporation-induced cell damage, but was mainly the result of the intracellular presence of plasmids. In contrast, pDNA transfection using Lipofectamine 2000 (LF2000) did not result in a significant loss of viability. Differences in delivery mechanism may explain the distinctive effects on cell viability. Indeed, electroporation is expected to cause a rapid and massive influx of pDNA resulting in cytosolic pDNA levels that most likely surpass the activation threshold of the intracellular DNA sensors leading to cell death. In contrast, a more sustained intracellular release of the pDNA is expected with LF2000. After lipofection with LF2000, 56% of the MDSCs were transfected and transgene expression lasted for at least 24 h. Moreover, biologically relevant amounts of IL-12 were produced by the MDSCs after lipofection with an IL-12 encoding pDNA. In addition, IL-12 transfection caused a significant upregulation of CD80 and considerably reduced the immunosuppressive capacity of the MDSCs. IL-12-transfected MDSCs were still able to migrate to tumor cells, albeit that lipofection of the MDSCs seemed to slightly decrease their migration capacity.

The challenge of West Nile virus in Europe: knowledge gaps and research priorities.

West Nile virus (WNV) is continuously spreading across Europe, and other continents, i.e. North and South America and many other regions of the world. Despite the overall sporadic nature of outbreaks with cases of West Nile neuroinvasive disease (WNND) in Europe, the spillover events have increased and the virus has been introduced into new areas. The high genetic diversity of the virus, with remarkable phenotypic variation, and its endemic circulation in several countries, require an intensification of the integrated and multidisciplinary research efforts built under the 7th Framework Programme of the European Union (FP7). It is important to better clarify several aspects of WNV circulation in Europe, including its ecology, genomic diversity, pathogenicity, transmissibility, diagnosis and control options, under different environmental and socio-economic scenarios. Identifying WNV endemic as well as infection-free areas is becoming a need for the development of human vaccines and therapeutics and the application of blood and organs safety regulations. This review, produced as a joint initiative among European experts and based on analysis of 118 scientific papers published between 2004 and 2014, provides the state of knowledge on WNV and highlights the existing knowledge and research gaps that need to be addressed with high priority in Europe and neighbouring countries.

Slowly fading super-luminous supernovae that are not pair-instability explosions.

Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10(-6) times that of the core-collapse rate.

Photon pair generation in a silicon micro-ring resonator with reverse bias enhancement.

Photon sources are fundamental components for any quantum photonic technology. The ability to generate high count-rate and low-noise correlated photon pairs via spontaneous parametric down-conversion using bulk crystals has been the cornerstone of modern quantum optics. However, future practical quantum technologies will require a scalable integration approach, and waveguide-based photon sources with high-count rate and low-noise characteristics will be an essential part of chip-based quantum technologies. Here, we demonstrate photon pair generation through spontaneous four-wave mixing in a silicon micro-ring resonator, reporting separately a maximum coincidence-to-accidental (CAR) ratio of 602 ± 37 (for a generation rate of 827kHz), and a maximum photon pair generation rate of 123 MHz ± 11 kHz (with a CAR value of 37). To overcome free-carrier related performance degradations we have investigated reverse biased p-i-n structures, demonstrating an improvement in the pair generation rate by a factor of up to 2 with negligible impact on CAR.

Fast path and polarization manipulation of telecom wavelength single photons in lithium niobate waveguide devices.

We demonstrate fast polarization and path control of photons at 1550 nm in lithium niobate waveguide devices using the electro-optic effect. We show heralded single photon state engineering, quantum interference, fast state preparation of two entangled photons, and feedback control of quantum interference. These results point the way to a single platform that will enable the integration of nonlinear single photon sources and fast reconfigurable circuits for future photonic quantum information science and technology.

Association study in eating disorders: TPH2 associates with anorexia nervosa and self-induced vomiting.

Twin studies suggest that genetic factors play a substantial role in anorexia nervosa (AN) and self-induced vomiting (SV), a key symptom that is shared among different types of eating disorders (EDs). We investigated the association of 25 single nucleotide polymorphisms (SNPs), capturing 71-91% of the common variance in candidate genes, stathmin (STMN1), serotonin receptor 1D (HTR1D), tryptophan hydroxylase 2 (TPH2) and brain-derived neurotrophic factor (BDNF), with AN and EDs characterized by regular SV. The first allele frequencies of all the SNPs were compared between a Dutch case group (182 AN, 149 EDs characterized by SV) and 607 controls. Associations rendering P-values < 0.05 from this initial study were then tested for replication in a meta-analysis with two additional independent ED case-control samples, together providing 887 AN cases, 306 cases with an ED characterized by SV and 1914 controls. A significant effect for the minor C-allele of tryptophan hydroxylase 2 rs1473473 was observed for both AN [odds ratio (OR) = 1.30, 95% CI 1.08-1.57, P < 0.003] and EDs characterized by SV (OR = 1.52, 95% CI 1.28-2.04, P < 0.006). In the combined case group, a dominant effect was observed for rs1473473 (OR = 1.38, 95% CI 1.16-1.64, P < 0.0003). The meta-analysis revealed that the tryptophan hydroxylase 2 polymorphism rs1473473 was associated with a higher risk for AN, EDs characterized by SV and for the combined group.

Influences on the structure of suburban ant (Hymenoptera: Formicidae) communities and the abundance of Tapinoma sessile.

Urbanization can alter the organization of ant communities and affect populations of urban pest ants. In this study, we sampled ant communities in urban and suburban yards to understand the habitat factors that shape these communities and influence the abundance of a common pest species, Tapinoma sessile (Say). We used pitfall traps to sample ant communities and a combination of pitfall traps and baiting to collect T. sessile at 24 sites in Knoxville, TN. In total, we collected 46 ant species. Ant species richness ranged from seven to 24 species per yard. Ant species richness tended to be lowest near houses, whereas T. sessile abundance was highest near houses. The best predictors of ant species richness in yards were canopy cover and presence of leaf litter: ant species richness peaked at mid-levels of canopy cover and was negatively correlated with the presence of leaf litter. Tapinoma sessile abundance increased with presence of logs, boards, or landscaping timbers and leaf litter in yards. Our results indicate that ant communities and the abundance of particular pest species in these urban and suburban landscapes are shaped by many of the same factors that structure ant communities in less anthropogenically disturbed environments.

Population-level traits that affect, and do not affect, invasion success.

What allows some species to successfully colonize a novel environment while others fail? Numerous studies in invasion biology have sought to answer this question, but those studies have tended to focus on traits of species or individuals (e.g. body size, seed size, seed number), and these traits have largely been found to be weak predictors of invasion success. However, characteristics of colonizing populations (e.g. genetic diversity, density, age structure) might also be important for successful establishment, as the authors of a study published in this issue of Molecular Ecology show (Crawford & Whitney 2010). By experimentally manipulating the density and genetic diversity of colonizing populations of Arabidopsis thaliana, the authors found that genetic diversity, but not population density, increased colonization success. Importantly, the effects of genetic diversity on colonization success were both additive and non-additive, suggesting that traits associated with particular genotypes and complimentarity among genotypes contribute to colonization success. This research highlights the importance of considering within-species variation and characteristics of entire populations in predicting colonization success.

Cutaneous short-interfering RNA therapy.

Since the 1990s, RNA interference (RNAi) has become a major subject of interest, not only as a tool for biological research, but also, more importantly, as a therapeutic approach for gene-related diseases. The use of short-interfering RNAs (siRNAs) for the sequence-specific knockdown of disease-causing genes has led to numerous preclinical and even a few clinical studies. Applications for cutaneous delivery of therapeutic siRNA are now emerging owing to a strong demand for effective treatments of various cutaneous disorders. Although successful studies have been performed using several different delivery techniques, most of these techniques encounter limitations for translation to the clinic with regards to patient compliance. This review describes the principal findings and applications in cutaneous RNAi therapy and focuses on the promises and pitfalls of the delivery systems.

Ultradeformable cationic liposomes for delivery of small interfering RNA (siRNA) into human primary melanocytes.

The aim of this work was to develop a system that can deliver siRNA into cells present in the human epidermis. More specifically, we wanted to block the expression of a specific Myosin Va exon F containing isoform that is physiologically involved in melanosome transport in human melanocytes. Therefore, we prepared and investigated the capacity of ultradeformable cationic liposomes (UCLs) to deliver siRNA in hard-to-transfect human primary melanocytes. UCLs were formulated from different w:w ratios (6:1, 8:1 and 10:1) of the cationic lipid 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) and the edge activator sodium cholate. Subsequently, UCL/siRNA complexes were prepared and their particle size, surface charge, deformability, cytotoxicity, transfection efficiency and long-term stability were tested. The best results were obtained with UCLs composed of a DOTAP/NaChol ratio of 6:1 (w:w) which are promising for future in vivo experiments.

Post-pegylated lipoplexes are promising vehicles for gene delivery in RPE cells.

The retinal pigment epithelium (RPE) is a potential tissue for gene therapy. We recently demonstrated that pegylation of lipoplexes prevents their aggregation in the vitreous of the eye. However, pegylation of lipoplexes may affect their gene transfer capacity. Therefore we studied the effect of pegylation of lipoplexes on the transfection of RPE cells. "Pre-pegylated" lipoplexes were prepared by mixing pDNA with pegylated liposomes, while "post-pegylated" lipoplexes were obtained by pegylation of (non-pegylated) cationic liposome/DNA complexes with PEG-ceramides. Pre-pegylation of lipoplexes severely inhibited their transfection efficacy. The poor transfection was attributed to an inefficient and slower internalization of pre-pegylated lipoplexes by RPE cells, compared to non-pegylated lipoplexes. In addition, pre-pegylated lipoplexes also remained entrapped in the endosomes of the RPE cells. In contrast, post-pegylation of the lipoplexes with PEG-ceramides strongly improved their transfection efficiency. As PEG-ceramides are believed to leave the lipoplexes upon contact with the cell membranes, this "de-pegylation" results in non-pegylated lipoplexes which successfully escape from the endosomes. In conclusion, post-pegylation of lipoplexes with PEG-ceramides appears to be an attractive strategy to deliver therapeutic DNA to RPE cells as (a) it prevents the lipoplexes from aggregation in vitreous and (b) de-pegylation upon contact with RPE membranes results in successful DNA delivery.

Challenges in non-viral ocular gene transfer.

Nowadays, there is no effective treatment for many retinal disorders. Knowledge of the genetic basis of many severe ocular diseases may allow for alternative treatments by gene therapy. Non-viral gene complexes, such as lipo- and poly-plexes, can be delivered to the posterior segment, most often the target tissue, by intravitreal or subretinal injection. Since subretinal injections are very invasive, intravitreal injection is a promising alternative route to deliver gene complexes into the eye. However, the drawback of this technique is the relative long distance the complexes have to travel through the vitreous gel before they reach the retina. This mini-review reports on how non-viral gene complexes behave in vitreous. It especially focuses on how the coating of lipoplexes with poly(ethylene glycol) influences their behaviour in vitreous and the transfection of retinal pigment epithelium.

Role of magnesium in the failure of rhDNase therapy in patients with cystic fibrosis.

BACKGROUND: In the management of cystic fibrosis (CF), rhDNase-I inhalation is widely used to facilitate the removal of the highly viscous and elastic mucus (often called sputum) from the lungs. However, an important group of CF patients does not benefit from rhDNase-I treatment. A study was undertaken to elucidate the reason for the failure of rhDNase-I in these patients and to evaluate strategies to overcome this. METHODS: The biochemical properties, physical properties, and degradation by rhDNase-I of sputum obtained from clinical responders and non-responders to rhDNase-I were compared, and the ability of magnesium to reactivate rhDNase-I in DNA solutions and in sputum was investigated. The effect of oral magnesium supplements on magnesium levels in the sputum of patients with CF was also examined. RESULTS: Sputum from clinical responders was extensively degraded in vitro on incubation with rhDNase-I, while sputum from clinical non-responders was not degraded: the median decrease in sputum elasticity in the two groups was 32% and 5%, respectively. Sputum from clinical responders contained significantly higher concentrations of magnesium than sputum from non-responders (2.0 mM v 1.3 mM; p = 0.020). Sputum that could not be degraded by rhDNase-I became degradable after preincubation with magnesium. The effect of magnesium on rhDNase-I activity was mediated through actin. Oral intake of magnesium enhanced the magnesium concentration in the sputum of CF patients. CONCLUSION: Increasing the magnesium concentration in sputum by, for example, oral magnesium supplements may be a promising new strategy to overcome the failure of rhDNase-I in patients with CF.

Delivery of phosphodiester oligonucleotides: can DOTAP/DOPE liposomes do the trick?

Delivering phosphodiester ONs (PO-ONs) remains an attractive but challenging goal in antisense therapy. Both in the literature and in our experiments, most cationic liposomes fail in generating an antisense effect with PO-ONs, while they succeed with chemically modified ONs such as phosphothioate ONs (PS-ONs). This work aims to explain the biological activity of PO- and PS-ONs delivered by DOTAP/DOPE liposomes based on a detailed understanding of their cell biological behavior by means of fluorescence correlation spectroscopy and confocal laser scanning microscopy. We conclude that DOTAP/DOPE liposomes are not suited to deliver PO-ONs due to the release of naked PO-ONs in the cytosol at the time of the endosomal escape of the liposomes and the subsequent rapid degradation of the naked PO-ONs. Carriers that would not release the PO-ONs upon endosomal escape but would continue to carry the PO-ONs until they arrive at the target mRNA could therefore be better suited to delivering PO-ONs. In the case of PS-ONs, the ONs are not degraded upon release at the time of the endosomal escape of the liposomes, creating a pool of intact, biologically active PS-ONs and thus making DOTAP/DOPE liposomes mainly suitable for delivering nuclease resistant ONs. However, the cells seemed to display an export pathway for removing intact PS-ONs from the cells, limiting the presence of naked PS-ONs in the nucleus to approximately 8 h following the delivery.