Expression dynamics of the aplysia abyssovirus.

Two recent studies documented the genome of a novel, extremely large (35.9 kb), nidovirus in RNA sequence databases from the marine neural model Aplysia californica. The goal of the present study was to document the distribution and transcriptional dynamics of this virus, Aplysia abyssovirus 1 (AAbV), in maricultured and wild animals. We confirmed previous findings that AAbV RNA is widespread and reaches extraordinary levels in apparently healthy animals. Transmission electron microscopy identified viral replication factories in ciliated gill epithelial cells but not in neurons where viral RNA is most highly expressed. Viral transcripts do not exhibit evidence of discontinuous RNA synthesis as in coronaviruses but are consistent with production of a single leaderless subgenomic RNA, as in the Gill-associated virus of Penaeus monodon. Splicing patterns in chronically infected adults suggested high levels of defective genomes, possibly explaining the lack of obvious disease signs in high viral load animals.

Thermal stress triggers productive viral infection of a key coral reef symbiont.

Climate change-driven ocean warming is increasing the frequency and severity of bleaching events, in which corals appear whitened after losing their dinoflagellate endosymbionts (family Symbiodiniaceae). Viral infections of Symbiodiniaceae may contribute to some bleaching signs, but little empirical evidence exists to support this hypothesis. We present the first temporal analysis of a lineage of Symbiodiniaceae-infecting positive-sense single-stranded RNA viruses ("dinoRNAVs") in coral colonies, which were exposed to a 5-day heat treatment (+2.1 °C). A total of 124 dinoRNAV major capsid protein gene "aminotypes" (unique amino acid sequences) were detected from five colonies of two closely related Pocillopora-Cladocopium (coral-symbiont) combinations in the experiment; most dinoRNAV aminotypes were shared between the two coral-symbiont combinations (64%) and among multiple colonies (82%). Throughout the experiment, seventeen dinoRNAV aminotypes were found only in heat-treated fragments, and 22 aminotypes were detected at higher relative abundances in heat-treated fragments. DinoRNAVs in fragments of some colonies exhibited higher alpha diversity and dispersion under heat stress. Together, these findings provide the first empirical evidence that exposure to high temperatures triggers some dinoRNAVs to switch from a persistent to a productive infection mode within heat-stressed corals. Over extended time frames, we hypothesize that cumulative dinoRNAV production in the Pocillopora-Cladocopium system could affect colony symbiotic status, for example, by decreasing Symbiodiniaceae densities within corals. This study sets the stage for reef-scale investigations of dinoRNAV dynamics during bleaching events.

Gel-like carbon dots: A high-performance future photocatalyst.

To protect water resources, halt waterborne diseases, and prevent future water crises, photocatalytic degradation of water pollutants arouse worldwide interest. However, considering the low degradation efficiency and risk of secondary pollution displayed by most metal-based photocatalysts, highly efficient and environmentally friendly photocatalysts with appropriate band gap, such as carbon dots (CDs), are in urgent demand. In this study, the photocatalytic activity of gel-like CDs (G-CDs) was studied using diverse water pollution models for photocatalytic degradation. The degradation rate constants demonstrated a remarkably enhanced photocatalytic activity of G-CDs compared with most known CD species and comparability to graphitic carbon nitride (g-C3N4). In addition, the rate constant was further improved by 1.4 times through the embedment of g-C3N4 in G-CDs to obtain CD-C3N4. Significantly, the rate constant was also higher than that of g-C3N4 alone, revealing a synergistic effect. Moreover, the use of diverse radical scavengers suggested that the main contributors to the photocatalytic degradation with G-CDs alone were superoxide radicals (O2-) and holes that were, however, substituted by O2- and hydroxyl radicals (OH) due to the addition of g-C3N4. Furthermore, the photocatalytic stabilities of G-CDs and CD-C3N4 turned out to be excellent after four cycles of dye degradation were performed continuously. Eventually, the nontoxicity and environmental friendliness of G-CDs and CD-C3N4 were displayed with sea urchin cytotoxicity tests. Hence, through various characterizations, photocatalytic degradation and cytotoxicity tests, G-CDs proved to be an environmentally friendly and highly efficient future photocatalyst.

Deformation of Needle Tips During Facial Soft Tissue Filler Injections: An Electron-Microscopic Study.

BACKGROUND: Injectable soft tissue fillers are used on a global scale for a variety of aesthetic indications. Despite their widespread use, there is a dearth of information regarding needle deformation following injection procedures. Repeated injections with the same needle could lead to progressive needle tip deformation, potentially resulting in decreased precision and increased patient discomfort. OBJECTIVES: The objective of this study was to quantify the magnitude of needle tip deformation utilizing scanning electron microscopy (SEM) image analysis. METHODS: An observational study was performed evaluating 4 differently sized needles following soft tissue filler injections for 5 different aesthetic indications (zygomatic arch, infraorbital, midcheek, nasolabial sulcus, and perioral) in patients aged 36 to 64 years. Following treatment, each needle was visualized and imaged through SEM, and the percentage of deformation in relation to the total amount of needle tip surface was calculated. RESULTS: The factor most influencing needle tip damage was revealed to be the number of injection passes, ie, dermal transitions. Per injection procedure, an increase in needle tip damage of 4.7% occurred. Touching the bone deformed the needle tip by 9.6% and an increase in needle size resulted in 0.13% more damage. CONCLUSIONS: To the authors' knowledge, this is the first SEM investigation to provide objective evidence for the deformation of needle tips after repeated facial soft tissue filler injections. These data may help improve patient safety and comfort during these minimally invasive procedures.

The Role of Hydrates, Competing Chemical Constituents, and Surface Composition on ClNO2 Formation.

Atomic chlorine (Cl•) affects air quality and atmospheric oxidizing capacity. Nitryl chloride (ClNO2) - a common Cl• source-forms when chloride-containing aerosols react with dinitrogen pentoxide (N2O5). A recent study showed that saline lakebed (playa) dust is an inland source of particulate chloride (Cl-) that generates high ClNO2. However, the underlying physiochemical factors responsible for observed yields are poorly understood. To elucidate these controlling factors, we utilized single particle and bulk techniques to determine the chemical composition and mineralogy of playa sediment and dust samples from the southwest United States. Single particle analysis shows trace highly hygroscopic magnesium and calcium Cl-containing minerals are present and likely facilitate ClNO2 formation at low humidity. Single particle and mineralogical analysis detected playa sediment organic matter that hinders N2O5 uptake as well as 10 Å-clay minerals (e.g., Illite) that compete with water and chloride for N2O5. Finally, we show that the composition of the aerosol surface, rather than the bulk, is critical in ClNO2 formation. These findings underscore the importance of mixing state, competing reactions, and surface chemistry on N2O5 uptake and ClNO2 yield for playa dusts and, likely, other aerosol systems. Therefore, consideration of particle surface composition is necessary to improve ClNO2 and air quality modeling.

Direct conjugation of distinct carbon dots as Lego-like building blocks for the assembly of versatile drug nanocarriers.

As a promising drug nanocarrier, carbon dots (CDs) have exhibited many excellent properties. However, some properties such as bone targeting and crossing the blood-brain barrier (BBB) only apply to a certain CD preparation with limited drug loading capacity. Therefore, it is significant to conjugate distinct CDs to centralize many unique properties on the novel drug nanocarrier. Considering that CDs have abundant and tunable surface functionalities, in this study, a direct conjugation was initiated between two distinct CD models, black CDs (B-CDs) and gel-like CDs (G-CDs) via an amidation reaction. As a result of conjugation at a mass ratio of 5:3 (B-CDs to G-CDs) and a two-step purification process, the conjugate, black-gel CDs (B-G CDs) (5:3) inherited functionalities from both CDs and obtained an enhanced thermostability, aqueous stability, red-shifted photoluminescence (PL) emission, and a figure-eight shape with a width and length of 3 and 6 nm, respectively. In addition, the necessity of high surface primary amine (NH2) content in the CD conjugation was highlighted by replacing G-CDs with other CDs with lower surface NH2 content. Meanwhile, the carboxyl groups (COOH) on G-CDs were not enough to trigger self-conjugation between G-CDs. Moreover, the drug loading capacity was enhanced by 54.5% from B-CDs to B-G CDs (5:3). Furthermore, when the mass ratio of B-CDs to G-CDs was decreased from 5:30, 5:100 to 5:300, the obtained nanostructures revealed a great potential of CDs as Lego-like building blocks. Also, bioimaging of zebrafish demonstrated that various B-G CDs exhibited properties of both bone targeting and crossing the BBB, which are specific properties of B-CDs and G-CDs, respectively.

Netosis and Inflammasomes in Large Vessel Occlusion Thrombi.

The inflammatory response appears to play a critical role in clotting in which neutrophil extracellular traps (NETs) are the major drivers of thrombosis in acute ischemic stroke (AIS). The inflammasome is an innate immune complex involved in the activation of interleukin (IL)-18 and IL-1ß through caspase-1, but whether the inflammasome plays a role in NETosis in AIS remains poorly understood. Here we assessed the levels of inflammasome signaling proteins in NETs and their association with clinical and procedural outcomes of mechanical thrombectomy for AIS. Electron microscopy and immunofluorescence indicate the presence of NETs in thrombi of patients with AIS. Moreover, the inflammasome signaling proteins caspase-1 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) were also present in clots associated with the marker of NETosis citrullinated histone 3H (CitH3). Analysis of protein levels by a simple plex assay show that caspase-1, ASC and interleukin (IL)-1ß were significantly elevated in clots when compared to plasma of AIS patients and healthy controls, while IL-18 levels were lower. Moreover, multivariate analyses show that IL-1ß levels in clots contribute to the number of passes to achieve complete recanalization, and that ASC, caspase-1 and IL-18 are significant contributors to time to recanalization. Thus, inflammasome proteins are elevated in NETs present in thrombi of patients with AIS that contribute to poor outcomes following stroke.

Photoluminescent Carbon Dots: A Mixture of Heterogeneous Fractions.

Photoluminescent carbon dots (CDs) fractions have been isolated from a gel-like material (GM), which was synthesized using a convenient one-step solvothermal route. In terms of purification, size exclusion chromatography (SEC) and dialysis were compared with acetone wash, which revealed the advantage of acetone wash. The pre-purified GM with acetone wash (A-GM) was further isolated by the reversed-phase preparative thin layer chromatography (TLC) with acetonitrile-water mixture (7 : 3; va /vw ) as the developing solvent. As a result, there were four photoluminescent bands on the TLC plate, which indicated the presence of four photoluminescent fractions. Detailed characterization measurements such as UV/Vis absorption, fluorescence emission, attenuated total reflection Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential, dynamic light scattering, atomic force microscopy, and TEM measurements were performed on all fractions to analyze their heterogeneous optical, structural, electrical, and morphological properties. Considering the comprehensive analysis, all isolated fractions were CDs. In addition, excitation wavelength-independent CDs were obtained with a mean size of 2.5 nm and high quantum yield (55 %). Furthermore, the study demonstrates that the excitation wavelength-dependent photoluminescence of GM could result from the mixture of different surface states of each CD fraction rather than multiple surface states of uniform CDs nanoparticles.

Carbon dots: promising biomaterials for bone-specific imaging and drug delivery.

Bone-related diseases and dysfunctions are heavy burdens on our increasingly aged society. One important strategy to relieve this problem is through early detection and treatment of bone-related diseases. Towards this goal, there has been constant interest in developing novel bone-specific materials for imaging and drug delivery. Currently, however, materials that have high affinity and specificity towards bone are very limited. Carbon dots (C-dots) synthesized from carbon nanopowder bind to calcified bones in vivo with high affinity and specificity. In this study we show that bone binding is highly unique to a specific type of C-dot, and that this binding is non-toxic. Significantly, C-dots derived from other raw materials did not show any bone binding properties. These differences are attributed to the differences in surface chemistry of C-dot preparations, highlighting the heterogeneous nature of C-dots. Importantly, bone-binding by carbon nanopowder derived C-dots is not significantly altered by chemical functionalization of their surface. These unique properties indicate the potential applications of carbon nanopowder-derived C-dots as highly bone-specific bioimaging agents and drug carriers.

Manganese oxide particles as cytoprotective, oxygen generating agents.

Cell culture and cellular transplant therapies are adversely affected by oxidative species and radicals. Herein, we present the production of bioactive manganese oxide nanoparticles for the purpose of radical scavenging and cytoprotection. Manganese comprises the core active structure of somatic enzymes that perform the same function, in vivo. Formulated nanoparticles were characterized structurally and surveyed for maximal activity (superoxide scavenging, hydrogen peroxide scavenging with resultant oxygen generation) and minimal cytotoxicity (48-h direct exposure to titrated manganese oxide concentrations). Cytoprotective capacity was tested using cell exposure to hydrogen peroxide in the presence or absence of the nanoparticles. Several ideal compounds were manufactured and utilized that showed complete disproportionation of superoxide produced by the xanthine/xanthine oxidase reaction. Further, the nanoparticles showed catalase-like activity by completely converting hydrogen peroxide into the corresponding concentration of oxygen. Finally, the particles protected cells (murine ß-cell insulinoma) against insult from hydrogen peroxide exposure. Based on these observed properties, these particles could be utilized to combat oxidative stress and inflammatory response in a variety of cell therapy applications. STATEMENT OF SIGNIFICANCE: Maintaining viability once cells have been removed from their physiological niche, e.g. culture and transplant, demands proper control of critical variables such as oxygenation and removal of harmful substances e.g. reactive oxygen species. Limited catalysts can transform reactive oxygen species into molecular oxygen and, thereby, have the potential to maintain cell viability and function. Among these are manganese oxide particles which are the subject of this study.

Gel-like Carbon Dots: Characterization and their Potential Applications.

Highly photoluminescent gel-like carbon dots (G-CDs) were successfully synthesized for the first time by a rapid one-step solvothermal synthesis approach with citric acid and 1,2-ethylenediamine as the precursors. Their gel-like nature was revealed by the Tyndall and coagulation effects, which were elucidated by a negative ζ potential value. The influences of temperature on the properties and sizes of these G-CDs were analyzed, and the best method for a maximum quantum yield was identified. The resulting products emitted blue photoluminescence under UV light (λ=365 nm) and a gradient of color under regular light. In addition, the UV/Vis absorption and fluorescence emission spectra of the G-CDs indicated that those synthesized at 160 °C exhibited the highest fluorescence quantum yield (33 %). Atomic force microscopy and transmission electron microscopy measurements were performed, and a higher temperature of formation resulted in smaller G-CDs. Furthermore, band shifts in the UV/Vis and fluorescence spectra and sequential changes in the quantum yield values and ζ potentials in addition to elemental compositional changes as determined by X-ray photoelectron spectroscopy were monitored throughout the formation process of the G-CDs. As to applications, G-CDs were prepared as an invisible ink for printers, which exhibited the applicability of G-CDs in daily life and military activities.

SHELL GROWTH IN THE SCALLOP ARGOPECTEN IRRADIANS. I. ISOTOPE INCORPORATION WITH REFERENCE TO DIURNAL GROWTH.

1. Incorporation of calcium and carbonate into shell has been studied in the scallop Argopecten irradians using 45Ca and 14C-bicarbonate. 2. The incorporation of 45Ca and 14C-carbonate into shell was linear with time after a lag period of 1 to 2 hours. The shell-forming mantle tissue attained a steady state with respect to 45Ca in the sea water medium within 2 hours. 3. The molar ratio of 45Ca to 14C-carbonate deposited in shell was not significantly different from unity during 5 hours. 4. The rate of incorporation of 14C-carbonate into shell was highest at the ventral edge and extremely low in the central and hinge areas. 5. The rate of incorporation at the ventral shell edge did not change with increase in shell size. 6. The rate of incorporation of carbonate was low at night when growth ridges form and increased 3-fold at midday when growth ridges are not being formed. 7. The protein content of the shell ridges was 32.9 ± 3.9% and the protein content of the shell including ridges was 16.0 ± 2.1%.