Comparison of the effects of sublethal concentrations of biofoulants, copper pyrithione and zinc pyrithione on a marine mysid - A multigenerational study.

To determine the effect of copper pyrithione (CuPT) and zinc pyrithione (ZnPT), a set of acute (96 h-LC50) and chronic endpoints was studied in the marine mysid, Neomysis awatschensis. Based on the 1/10 NOECs and NOEC values calculated from 96 h-toxicity test, survival and growth, intermolt duration, feeding, and the number of newborn juveniles were measured by evaluating enzymatic activity of detoxification parameter glutathione S-transferase (GST) and cholinergic biomarker acetylcholinesterase (AChE) in the marine mysid exposed to 96 h-NOECs of CuPT and ZnPT for four weeks across three generations. Dose-dependent decreases in survival rate monitored for four weeks were observed with age-specific sensitivity in response to the 96 h-NOECs of both antifoulants. Higher growth retardation was observed with an increase in intermolt duration and inhibition of the feeding rate in CuPT-exposed mysid compared to ZnPT-exposed mysid across generations. The numbers of newborn juveniles significantly decreased at the third generation by exposure to the 96 h-NOECs of both antifoulants. GST activity was significantly inhibited in response to 96 h-NOECs of both antifoulants, whereas AChE activity was only reduced by the 96 h-NOECs of CuPT at the third generation. These results indicate that CuPT has a higher toxicity than ZnPT and even sublethal levels of CuPT and ZnPT would have detrimental effects on the maintenance of the mysid population. Finally, consistent exposure to environmentally relevant concentrations of CuPT and ZnPT can induce intergenerational toxicity in mysid.

Wafer-Scale Epitaxial Growth of an Atomically Thin Single-Crystal Insulator as a Substrate of Two-Dimensional Material Field-Effect Transistors.

As the electron mobility of two-dimensional (2D) materials is dependent on an insulating substrate, the nonuniform surface charge and morphology of silicon dioxide (SiO2) layers degrade the electron mobility of 2D materials. Here, we demonstrate that an atomically thin single-crystal insulating layer of silicon oxynitride (SiON) can be grown epitaxially on a SiC wafer at a wafer scale and find that the electron mobility of graphene field-effect transistors on the SiON layer is 1.5 times higher than that of graphene field-effect transistors on typical SiO2 films. Microscale and nanoscale void defects caused by heterostructure growth were eliminated for the wafer-scale growth of the single-crystal SiON layer. The single-crystal SiON layer can be grown on a SiC wafer with a single thermal process. This simple fabrication process, compatible with commercial semiconductor fabrication processes, makes the layer an excellent replacement for the SiO2/Si wafer.

Exposure to Environmentally Relevant Concentrations of Polystyrene Microplastics Increases Hexavalent Chromium Toxicity in Aquatic Animals.

The prevalence of hexavalent chromium [Cr(VI)] and microplastics (MPs) is ubiquitous and is considered a threat to aquatic biota. MPs can act as a vector for waterborne metals; however, the combined effects of Cr(VI) and MPs on aquatic organisms are largely unknown. In this study, aquatic model animals, such as rotifers (Brachionus calyciflorus and B. plicatilis), water fleas (Daphnia magna), amphipods (Hyalella azteca), polychaetes (Perinereis aibuhitensis), and zebrafish (Danio rerio) were exposed to environmental concentrations (1, 10, and 100 particles L-1) of 1 µm polystyrene MPs alone, Cr(VI) alone, or Cr(VI) combined with MPs. Following exposure, the potential effects were measured by analyzing basic life endpoints (e.g., survival rate and growth). A significant response to MPs alone was not observed in all animals. However, MPs combined with Cr(VI) concentration-dependently increased Cr(VI) toxicity in two rotifer species. The survival rate of water fleas was significantly reduced upon exposure to Cr(VI) + MPs (100 particles L-1) compared with exposure to Cr(VI) alone, and significantly decreased the number of offspring. Although there was no significant effect on the body length of the amphipod, concentration-dependent decreases in their survival rates were observed. In contrast, no significant change was found in the survival rate of polychaetes; however, their burrowing ability was inhibited by Cr(VI) + MPs (100 particles L-1). Further, larval mortality was increased in response to Cr(VI) + MPs (100 particles L-1) in zebrafish. Taken together, the findings suggest that MPs can exacerbate Cr(VI) toxicity, even at environmental levels.

Change in Bone Mineral Density in Stroke Patients with Osteoporosis or Osteopenia.

We aimed to investigate the correlation between changes in bone mineral density (BMD) of the lumbar spine (LS) and femoral neck (FN) and osteoporosis-related factors in stroke patients with osteoporosis or osteopenia, and we suggest the need for active rehabilitation treatment. This study included 63 osteoporosis and 34 osteopenia patients who underwent a BMD test following primary stroke onset. The osteoporosis group was followed up with a BMD test after 12 months of bisphosphonate treatment, and the osteopenia group was followed up without medication. The correlation between BMD changes and functional factors was analyzed, biochemical markers were measured, and hematology tests were performed. In the osteoporosis group, a significant increase was observed in LS BMD (p < 0.05), and in the osteopenia group, there was a significant decrease in FN BMD (p < 0.05). The group with a functional ambulatory category of 1 or more showed a significant improvement in BMD (p < 0.05). Comparative analysis was performed on various indicators, but no significant correlation was found between any variable. In stroke patients with osteoporosis or osteopenia, early appropriate drug treatment is important to prevent bone loss and reduce the risk of fractures, and comprehensive rehabilitation treatment, such as appropriate education and training to prevent falls, is essential.

A solvent-free headspace GC/MS method for sensitive screening of N-nitrosodimethylamine in drug products.

A solvent-free headspace gas chromatography-mass spectrometry (SF-HS-GC/MS) method was developed and validated for screening N-nitrosodimethylamine (NDMA) in various active pharmaceutical ingredients (APIs) and drug products. Experimental parameters such as incubation temperature, incubation time, and sample volume in solvent-free headspace conditions were optimized. The developed SF-HS-GC/MS method was validated in terms of linearity, limit of quantification (LOQ), precision, and accuracy. The results indicated excellent linearity from 5 to 500 ng g-1 with correlation coefficients higher than 0.9999. The LOQ of this method was 5 ng g-1 and matrix effects ranged from 0.97 to 1.11. The accuracy ranged from 92.77 to 106.54% and the precision RSDs were below 5.94%. No significant matrix effect was observed for any of the drug products. Also, artefactual NDMA formation in ranitidine, nizatidine, and metformin was investigated under HS conditions. Adjusted (mild) SF-HS conditions were suggested for precise quantification of NDMA in positive drug products by GC/MS. The present SF-HS-GC/MS method is a promising tool for the screening and determination of toxic NDMA in APIs and drug products.

Anterior gradient 2 is involved in the post-transcriptional regulation of ß-dystroglycan.

Anterior gradient 2 (AGR2) is a protein disulfide isomerase over-expressed in numerous types of cancer. Although AGR2 plays a role in ER homeostasis, its function(s) in tumorigenesis is still elusive. Here we demonstrate that AGR2 is involved in the regulation of the ß-subunit of dystroglycan (ß-DG), a component of the multi-protein complex linking the extracellular matrix and cytoskeletal network. In breast cancer cells, AGR2 over-expression led to the up-regulation of ß-DG but not that of α-DG, while the transcript levels of these subunits were unchanged. Conversely, the reduced expression of AGR2 caused the down-regulation of ß-DG. Interestingly, induced expression of AGR2 increased the degree of co-localization of AGR2 and ß-DG in the cytoplasm suggesting that AGR2 facilitates the trafficking of ß-DG. In addition, AGR2 over-expression caused the re-arrangement of the actin cytoskeletal network. Presumably over-expressed AGR2 up-regulates ß-DG post-transcriptionally and facilitates its trafficking, which then causes re-arrangement of the cytoskeletal network, which plays a role in the adhesion and invasion of cancer cells.

Synthesis of high quality 2D carbide MXene flakes using a highly purified MAX precursor for ink applications.

The practical application of 2D MXenes in electronic and energy fields has been hindered by the severe variation in the quality of MXene products depending on the parent MAX phases, manufacturing techniques, and preparation parameters. In particular, their synthesis has been impeded by the lack of studies reporting the synthesis of high-quality parent MAX phases. In addition, controllable and uniform deposition of 2D MXenes on various large-scale substrates is urgently required to use them practically. Herein, a method of pelletizing raw materials could synthesize a stoichiometric Ti3AlC2 MAX phase with high yield and processability, and fewer impurities. The Ti3AlC2 could be exfoliated into 1-2-atom-thick 2D Ti3C2T x flakes, and their applicability was confirmed by the deposition and additional alignment of the 2D flakes with tunable thickness and electrical properties. Moreover, a practical MXene ink was fabricated with rheological characterization. MXene ink exhibited much better thickness uniformity while retaining excellent electrical performances (e.g., sheet resistance, electromagnetic interference shielding ability) as those of a film produced by vacuum filtration. The direct functional integration of MXenes on various substrates is expected to initiate new and unexpected MXene-based applications.

Consistent exposure to microplastics induces age-specific physiological and biochemical changes in a marine mysid.

In this study, a marine mysid, Neomysis awatschensis, was exposed to 1 × 103-5 × 105 particles mL-1 of polystyrene microbeads (1 and 10 µm). Exposure to microplastics (MPs) resulted in ingestion and egestion in feces. MPs exposure during the early stage resulted in mortality and oxidative stress, while more mature stages were increasingly tolerant to MPs. Feeding rates were inhibited by MPs, and age-specific oxidative stress was observed. Growth parameters were significantly affected by MPs with lower 20-hydroxyecdysone (20E) concentrations and longer intermolt durations. The number of hatched juveniles from females that were exposed to MPs was significantly lower than the control treatment, but no significant differences were observed between survival rates of newly hatched juveniles in the different treatments. Our results suggest that the detrimental effects of prolonged exposure to MPs could be age- and size-specific and harmful for the maintenance of mysid populations.

Fabrication of Bioabsorbable Polylactic-Co-Glycolic Acid/Polycaprolactone Nanofiber Coated Stent and Investigation of Biodegradability in Porcine Animal Model.

Stent-mediated therapy is minimally invasive and fairly effective for the specific tissue and organs with tubal structures such as the esophagus, intestine, and blood vessels. Cerebral arteries are one of the most critical tubal structures to maintain the physiological function and the life of the human. Since the retrieval of the implanted vascular stent is difficult and risky, the one-step stent therapy is imperative. However, the placement of a current pipe-typed stent can also limit the nutritional supply to the vascular wall. Also, the non-degradable polymeric layer is possibly sensitized to the recipient as a foreign body after prolonged period after implantation. Herein, we developed PLGA/PCL nanofiber-coated stent for blocking the flow towards the aneurysm cavity as well as allowing nutritional support to the vessel with the biodegradability. The PLGA/PCL nanofiber-coated stent (NCS) was fabricated via electrospinning composite nanofibers onto a self-expandable mater metal stent. The as-fabricated NCS was physicochemically characterized using FT-IR, FE-SEM, and UTM, and experimented in vivo as implanted in porcine models and radiologically and histologically analyzed. The NCS demonstrated improved physicochemical properties for intracranial aneurysmal treatment including enhanced mechanical properties. The bioabsorbability of NCS was confirmed in the animal model.

A proteomic analysis of differentiating dopamine neurons derived from human embryonic stem cells.

Human embryonic stem cells (hESC) are being exploited for potential use in cell transplantation due to their capacity for self-renewal and pluripotency. Dopamine (DA) neurons derived from hESC represent a promising source of cell replacement therapy for Parkinson's disease (PD). While gene expression on the transcriptome level has been extensively studied, limited information is available for the proteome-level changes associated with DA neuron differentiation. Here we analyzed the proteome of differentiating DA neurons to search for the potential biomarkers to assess the efficiency of differentiation. Although the proteome profile of DA neurons did not exhibit significant changes, a number of cytoskeletal proteins including nuclear lamin, tropomyosin 1, and myosin light chain 1 were specifically up-regulated during differentiation. Expression analysis of the respective genes was also consistent with the proteome results. In addition, these differentially expressed proteins form protein interaction network with several PD-related proteins suggesting that they may play roles in PD pathogenesis as well as the maturation of DA neurons.

Effects of sublethal concentrations of the antifouling biocide Sea-Nine on biochemical parameters of the marine polychaete Perinereis aibuhitensis.

Sea-Nine™ 211 is an emerging biocide that has an adverse impact on aquatic environments. In this study, the marine polychaete Perinereis aibuhitensis was exposed to Sea-Nine (0.1, 1, and 10 µg L-1), and acute toxicity and biochemical responses such as changes in the intracellular contents of malondialdehyde (MDA) and glutathione (GSH) and enzymatic activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and acetylcholinesterase (AChE) were evaluated over a period of 14 d. Determined median lethal doses, LC50 were 268 µg L-1, 142 µg L-1, and 55 µg L-1 at 24 h, 96 h, and 14 d, respectively. The MDA content increased significantly in a dose- and time-dependent manner, indicative of lipid peroxidation-related oxidative damage. Significantly higher intracellular GSH levels and antioxidant defense-related enzyme (CAT, SOD, GPx, GR, and GST) activities were observed after exposure to 10 µg L-1 Sea-Nine. In contrast, Sea-Nine treatment significantly reduced AChE activity at the highest concentration of Sea-Nine used (10 µg L-1). Taken together, these results indicate that sublethal concentrations of Sea-Nine are toxic to marine polychaetes through potential lipid peroxidation, induction of oxidative stress, and modulation of the cholinergic system. Our results can contribute to biomonitoring of aquatic environments and ecotoxicological research through the measurements of polychaete cellular defenses against waterborne biocides.

Ultrathin Graphene Intercalation in PEDOT:PSS/Colorless Polyimide-Based Transparent Electrodes for Enhancement of Optoelectronic Performance and Operational Stability of Organic Devices.

A novel flexible transparent electrode (TE) having a trilayer-stacked geometry and high optoelectronic performance and operational stability was fabricated by the spin coating method. The trilayer was composed of an ultrathin graphene (Gr) film sandwiched between a transparent and colorless polyimide (TCPI) layer and a methanesulfonic acid (MSA)-treated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer containing dimethylsulfoxide and Zonyl fluorosurfactant (designated as MSA-PDZ film). The introduction of solution-processable TCPI enabled the direct formation of high-quality graphene on organic surfaces with a clean interface. Stable doping of graphene with the MSA-PDZ film enabled tuning of the inherent work function and optoelectronic properties of the PEDOT:PSS films, leading to a high figure of merit of ∼70 in the as-fabricated TEs. Particularly, from multivariate and repetitive harsh environmental tests ( T = -50 to 90 °C, over 90 RH%), the TCPI/Gr heterostructure exhibited excellent tolerance to mechanical and thermal stresses and gas barrier properties that protected the MSA-PDZ film from exposure to moisture. Owing to the synergetic effect from the TCPI/Gr/MSA-PDZ anode structure, the TCPI/Gr/MSA-PDZ-based polymer light-emitting diodes showed highly improved current and power efficiencies with maxima as high as 20.84 cd/A and 22.92 lm/W, respectively (comparable to those of indium tin oxide based PLEDs), in addition to much enhanced mechanical flexibility.

Electrically Robust Single-Crystalline WTe2 Nanobelts for Nanoscale Electrical Interconnects.

As the elements of integrated circuits are downsized to the nanoscale, the current Cu-based interconnects are facing limitations due to increased resistivity and decreased current-carrying capacity because of scaling. Here, the bottom-up synthesis of single-crystalline WTe2 nanobelts and low- and high-field electrical characterization of nanoscale interconnect test structures in various ambient conditions are reported. Unlike exfoliated flakes obtained by the top-down approach, the bottom-up growth mode of WTe2 nanobelts allows systemic characterization of the electrical properties of WTe2 single crystals as a function of channel dimensions. Using a 1D heat transport model and a power law, it is determined that the breakdown of WTe2 devices under vacuum and with AlO x capping layer follows an ideal pattern for Joule heating, far from edge scattering. High-field electrical measurements and self-heating modeling demonstrate that the WTe2 nanobelts have a breakdown current density approaching ≈100 MA cm-2, remarkably higher than those of conventional metals and other transition-metal chalcogenides, and sustain the highest electrical power per channel length (≈16.4 W cm-1) among the interconnect candidates. The results suggest superior robustness of WTe2 against high-bias sweep and its possible applicability in future nanoelectronics.

Protective effects of α-lipoic acid on cultured human nasal fibroblasts exposed to urban particulate matter.

BACKGROUND: Exposure to urban particulate matter (UPM) has been studied as a cause of various health problems. Although the association between UPM and the respiratory tract has been well studied, further research is required to characterize the effects of UPM on the upper respiratory tract. We investigated the effects of UPM-induced reactive oxygen species (ROS) production on cultured human nasal fibroblasts, as well as the protective effects of α-lipoic acid (ALA) on ROS production and the underlying signaling pathways involved in ROS inhibition. METHODS: Human turbinate tissue specimens were collected from 6 patients. The effects of UPM on the viability of cultured nasal fibroblasts were determined. A fluorescent malondialdehyde assay was used to measure ROS levels. Real-time reverse transcription polymerase chain reaction was used to measure the messenger RNA levels of genes encoding Nrf2, the antioxidant response elements (AREs) (HO-1, NQO1), and the proinflammatory cytokines (interleukin-6 and interleukin-8) before and after ALA treatment. Western blotting analyses were used to measure nuclear and cytosolic Nrf2 and AREs. RESULTS: UPM reduced cell viability and increased ROS expression in nasal fibroblasts. ALA treatment decreased ROS production in UPM-exposed fibroblasts via the Nrf2, HO-1, and NQO-1 pathways. Also, ALA treatment abrogated increases in the interleukin-6 and -8 levels induced by UPM in nasal fibroblasts. CONCLUSION: UPM exposure resulted in increased ROS production in nasal fibroblasts. ALA treatment inhibited this increase via the Nrf2 pathway, suggesting that ALA may have a protective effect against rhinitis caused by ROS expression induced by exposure to UPM.

Magnetic Resonance Imaging Distortion and Targeting Errors from Strong Rare Earth Metal Magnetic Dental Implant Requiring Revision.

Recently, the use of magnetic dental implants has been re-popularized with the introduction of strong rare earth metal, for example, neodymium, magnets. Unrecognized magnetic dental implants can cause critical magnetic resonance image distortions. We report a case involving surgical failure caused by a magnetic dental implant. A 62-year-old man underwent deep brain stimulation for medically insufficiently controlled Parkinson"s disease. Stereotactic magnetic resonance imaging performed for the first deep brain stimulation showed that the overdenture was removed. However, a dental implant remained and contained a neodymium magnet, which was unrecognized at the time of imaging; the magnet caused localized non-linear distortions that were the largest around the dental magnets. In the magnetic field, the subthalamic area was distorted by a 4.6 mm right shift and counter clockwise rotation. However, distortions were visually subtle in the operation field and small for distant stereotactic markers, with approximately 1-2 mm distortions. The surgeon considered the distortion to be normal asymmetry or variation. Stereotactic marker distortion was calculated to be in the acceptable range in the surgical planning software. Targeting errors, approximately 5 mm on the right side and 2 mm on the left side, occurred postoperatively. Both leads were revised after the removal of dental magnets. Dental magnets may cause surgical failures and should be checked and removed before stereotactic surgery. Our findings should be considered when reviewing surgical precautions and making distortion-detection algorithm improvements.

Complete mitochondrial genome of the marine mysid Siriella sp. (Crustacea, Mysida, Mysidae).

The complete mitochondrial genome of the marine mysid, Siriella sp. was obtained by conventional polymerase chain reaction (PCR) method. Total length of Siriella sp. mitochondrial genome was 14,706 bp, with the base composition of 27% A, 21% C, 22% G, and 30% T with a high AT bias of 57%. The mitogenome of Siriella sp. contained 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and a putative control region. Maximum likelihood method-based phylogenetic reconstruction suggested the evolutionary relationship to other mysids within the order Mysida. Since Mysida contains numerous species across a wide range of water habitats, this information will provide an essential molecular reference to elucidate biogeography, phylogenetic distance, and evolutionary diversity in mysids. This is the first mitogenome information in the genus Siriella.

Long-term exposure to waterborne nonylphenol alters reproductive physiological parameters in economically important marine fish.

Low concentrations of nonylphenol (NP) in aquatic environment can induce drastic effects on the endocrine system in animals. In this study, we examined the modulatory effects of NP on reproductive and physiological parameters in juveniles of the red seabream and black rockfish following waterborne NP exposure (0, 1, 10, and 50 µg L-1) for 60 days. In red seabream exposed to 50 µg L-1 NP, plasma levels of 17ß-estradiol (E2) and 11-ketotestosterone (11-KT) were significantly lower at 30 and 60 days, while E2 levels were slightly higher in 10 µg L-1-exposed individuals at day 30. Similarly, significantly lower levels of E2 and 11-KT were observed in 10 and 50 µg L-1-exposed black rockfish at 60 days, whereas the E2 level was higher in 1 µg L-1-exposed individuals at day 30. After exposure to NP, plasma and mRNA levels of vitellogenin (VTG) were significantly higher in both species at 30 and 60 days, similar to the inducible effects from synthetic estrogen. Plasma cortisol levels were significantly elevated by relatively higher concentrations of NP (10 and 50 µg L-1) at 30 and 60 days. Finally, 60 days of exposure of 50 µg L-1 NP significantly decreased the gonadosomatic index (GSI) and increased the hepatosomatic index (HSI) in both species. The results obtained from this study provide an evidence of the endocrine disrupting potential of waterborne NP on early stages of economically important marine fish. The NP-triggered endocrine modulation can induce effects on the development of reproductive and metabolic organs in fish species.

Constant exposure to environmental concentrations of the antifouling biocide Sea-Nine retards growth and reduces acetylcholinesterase activity in a marine mysid.

Sea-Nine (4,5-dichloro-2-n-octyl-4-isothiazoline3-one; DCOIT) antifoulant has been widely used owing to its broad spectrum of biocide activity against major fouling organisms. In this study, several physiological parameters of a marine mysid were analyzed upon exposure to sublethal environmental concentrations (1 and 100 ng L-1) of Sea-Nine in two exposure conditions, intermittent (weekly; once per week) and constant (daily; once per 24 h) exposure, for 4 weeks. In both experimental conditions, growth retardation, acetylcholinesterase (AChE) activity, glutathione S-transferase (GST) activity, and number of newborn juveniles as second generation, together with their survival were measured. Morphometric parameters of total body, antennal scale, exopod, endopod, and telson were significantly retarded by 22%, 14%, 13%, and 24%, respectively, by daily exposure to 100 ng L-1 Sea-Nine for 4 weeks. Significant inhibition of AChE activity was observed at week 4 in the 100 ng L-1 daily Sea-Nine-exposed groups, whereas no significant GST activity was measured at the same experimental conditions. Inhibition of AChE activity would be associated with impairment of cholinergic system and may adversely modulate growth parameters of the mysid. The number of newly hatched juveniles from females that were exposed daily to 100 ng L-1 Sea-Nine was significantly lower than that of the control. Although no significant differences were observed between survival percentages of newborn juveniles for 30 days, mortality (NOEC and LC50) increased in the surviving offspring from the 100 ng L-1-exposed 1st generation of mysids. These findings suggested that constant exposure to Sea-Nine has detrimental effects on the growth parameters of marine mysids with inhibition of AChE activity.

Dual-specificity phosphatase 18 modulates the SUMOylation and aggregation of Ataxin-1.

We previously reported that SUMOylation promotes the aggregation of ataxin-1 and JNK is involved in the process. Here we show that dual-specificity phosphatase 18 (DUSP18), a member of protein tyrosine phosphatases, exerts the opposite effects on ataxin-1. DUSP18 associated with ataxin-1 and suppressed JNK activated by ataxin-1. Interestingly DUSP18, but not the other DUSPs interacting with ataxin-1, caused the mobility shift of ataxin-1. De-phosphorylation by DUSP18 was initially suspected as a cause for such an effect; however, the phosphorylation of ataxin-1 was unchanged. Instead DUSP18 inhibited SUMOylation and reduced ataxin-1 aggregation. The catalytic mutant of DUSP18 failed to reduce the SUMOylation and aggregation of ataxin-1 indicating that the phosphatase activity is indispensable for the effects. Moreover, DUSP18 disrupted the co-localization of ataxin-1 with the PML component Sp100. These results together implicate that JNK and DUSP18 reciprocally modulate the SUMOylation, which plays a regulatory role in the aggregation of ataxin-1.

Exposure to sublethal concentrations of tributyltin reduced survival, growth, and 20-hydroxyecdysone levels in a marine mysid.

Tributyltin (TBT) is as an antifouling organotin compound used in boat paints. Although organotin-based antifouling agents have been banned on a global scale, the mode of action of TBT has been studied in numerous aquatic species because of its toxicity, persistence, bioaccumulation potential, and endocrine-disrupting characteristics. In this study, we conducted 96-h acute toxicity tests wherein we exposed juvenile and adult marine mysids to waterborne TBT. Over 4 weeks of exposure, mortality was dose-dependently increased in juveniles and adult mysids. To test sublethal effects of TBT on juvenile development, newborn juvenile mysids were exposed to 1, 5, or 10 ng L-1 TBT for 4 weeks. Subsequently, we measured morphological growth parameters and quantified the hormone ecdysterone (20-hydroxyecdysone: 20E), which controls molting in mysids. The lengths of the whole body, antennal scale, exopod, endopod, and telson were significantly smaller in the 5 and/or 10 ng L-1 TBT-exposed juvenile mysids than in control and DMSO-exposed groups. Levels of 20E were significantly lower at 5 and 10 ng L-1 TBT exposures. Additionally, the number of newly hatched juveniles was significantly lower from females previously exposed to 10 ng L-1 TBT. Our results indicate sublethal concentrations of TBT have inhibitory effects on the survival, growth, and production of juveniles. The lower 20E levels could be strongly associated with TBT-triggered inhibition.