Defects in actin-cap formation in Vav-deficient mice implicate an actin requirement for lymphocyte signal transduction

BACKGROUND

Antigen-receptor interactions on lymphocytes result in local clustering of actin, receptors and signaling molecules into an asymmetric membrane structure termed a cap. Although actin polymerization is known to be required, the mechanisms underlying cap formation are unclear. We have studied the events underlying cap formation using mice bearing a null mutation in vav (vav-/-), a gene that encodes a guanine-nucleotide exchange factor for the GTPase Rac.

RESULTS

Lymphocytes from vav-/- mice failed to form T-cell receptor caps following activation and had a defective actin cytoskeleton. The vav-/- T cells were deficient in interleukin-2 (IL-2) production and proliferation, and the peak of Ca2+ mobilization was reduced although of normal duration. Activation of Jun N-terminal kinase or stress-activated kinase (JNK or SAPK) and mitogen-activated protein kinase (MAPK) and the induction of the transcription factor NF-ATc1 and egr-1 genes was normal. Despite the reduced Ca2+ mobilization, translocation of cytoplasmic NF-ATc to the nucleus was normal, reflecting that the lower levels of Ca2+ in vav-/- cells were still sufficient to activate calcineurin. Treatment of lymphocytes with cytochalasin D, which blocks actin polymerization, inhibited cap formation and produced defects in signaling and IL-2 transcriptional induction in response to antigen-receptor signaling that were nearly identical to those seen in vav-/- cells. In transfection studies, either constitutively active Vav or Rac could complement constitutively active calcineurin to activate NF-AT-dependent transcription.

CONCLUSIONS

These results indicate that Vav is required for cap formation in lymphocytes. Furthermore, the correlation between cap formation, IL-2 production and proliferation supports the hypothesis that an actin-dependent pathway is a source of specialized growth regulatory signals.

Spectro-temporal modulation transfer functions and speech intelligibility

Detection thresholds for spectral and temporal modulations are measured using broadband spectra with sinusoidally rippled profiles that drift up or down the log-frequency axis at constant velocities. Spectro-temporal modulation transfer functions (MTFs) are derived as a function of ripple peak density (omega cycles/octave) and drifting velocity (omega Hz). The MTFs exhibit a low-pass function with respect to both dimensions, with 50% bandwidths of about 16 Hz and 2 cycles/octave. The data replicate (as special cases) previously measured purely temporal MTFs (omega = 0) [Viemeister, J. Acoust. Soc. Am. 66, 1364-1380 (1979)] and purely spectral MTFs (omega = 0) [Green, in Auditory Frequency Selectivity (Plenum, Cambridge, 1986), pp. 351-359]. A computational auditory model is presented that exhibits spectro-temporal MTFs consistent with the salient trends in the data. The model is used to demonstrate the potential relevance of these MTFs to the assessment of speech intelligibility in noise and reverberant conditions.

A general mechanism for transcriptional synergy by eukaryotic activators

One of the important regulatory concepts to emerge from studies of eukaryotic gene expression is that RNA polymerase II promoters and their upstream activators are composed of functional modules whose synergistic action regulates the transcriptional activity of a nearby gene. Biochemical analysis of synergy by ZEBRA, a non-acidic activator of the Epstein-Barr virus (EBV) lytic cycle, showed that the synergistic transcriptional effect of promoter sites and activation modules correlates with assembly of the TFIID:TFIIA (DA) complex in DNase I footprinting and gel shift assays. The activator-dependent DA complex differs from a basal DA complex by its ability to bind TFIIB stably in an interaction regulated by TATA-binding protein-associated factors (TAFs). TFIIB enhances the degree of synergism by increasing complex stability. Similar findings were made with the acidic activator GAL4-VP16. Our data suggest a unifying mechanism for gene activation and synergy by acidic and non-acidic activators, and indicate that synergy is manifested at the earliest stage of preinitiation complex assembly.

Racial differences in optic nerve head parameters

Results of previous studies have strongly indicated that the prevalence of elevated intraocular pressure is greater in blacks than in whites and that blacks are more susceptible than whites to glaucomatous damage at any given level of pressure. It has also been suggested that a larger disc area might predispose an eye to glaucomatous damage. We investigated the possibility that clinically quantifiable differences might exist in optic disc parameters between normotensive white and black patients. Disc area, cup-to-disc ratio, and cup volume measured with a video-ophthalmograph (Rodenstock Optic Disc Analyzer) were significantly larger in blacks than in whites, while there was no difference in the disc rim area between the two groups. We derived a mathematical model of the optic disc that relates posterior displacement of the lamina cribrosa to the disc area, distensibility of the disc, and intraocular pressure.

Architectural DNA binding by a high-mobility-group/kinesin-like subunit in mammalian SWI/SNF-related complexes

The SWI/SNF complex in yeast and Drosophila is thought to facilitate transcriptional activation of specific genes by antagonizing chromatin-mediated transcriptional repression. The mechanism by which it is targeted to specific genes is poorly understood and may involve direct DNA binding and/or interactions with specific or general transcription factors. We have previously purified a mammalian complex by using antibodies against BRG1, a human homologue of SWI2/SNF2. This complex is likely functionally related to the yeast SWI/SNF complex because all five subunit identified so far (referred to as BAFs, for BRG1-associated factors) are homologues of the yeast SWI/SNF subunits. However, we now describe the cloning of the 57-kDa subunit (BAF57), which is present only in higher eukaryotes but not in yeast. BAF57 is shared by all mammalian complexes and contains a high-mobility-group (HMG) domain adjacent to a kinesin-like region. Both recombinant BAF57 and the whole complex bind four-way junction (4WJ) DNA, which is thought to mimic the topology of DNA as it enters or exits the nucleosome. Surprisingly, complexes with mutations in the HMG domain of BAF57 can still bind 4WJ DNA and mediate ATP-dependent nucleosome disruption. Our work describes the first DNA binding subunit for SWI/SNF-like complexes and suggest that the mechanism by which mammalian and Drosophila SWI/SNF-like complexes interact with chromatin may involve recognition of higher-order chromatin structure by two or more DNA binding domains.

Assembly of the isomerized TFIIA--TFIID--TATA ternary complex is necessary and sufficient for gene activation

The prevailing view of eukaryotic gene activation poses that activators stimulate transcription by recruiting limiting components of the general transcription machinery to a core promoter. In one such model case, activation by the Epstein-Barr virus ZEBRA protein correlated closely with recruitment of the general transcription factors TFIIA and TFIID (the DA complex) as measured by DNase I footprinting and gel mobility shift assays. We now report that simple recruitment is not sufficient for full-level activation. An additional concentration-independent, rate-limiting step is activator-mediated isomerization of the DA complex characterized by an extended TFIID footprint. The isomerized complex supports both binding of TFIIB in gel mobility shift assays and activated transcription in heat-treated nuclear extracts, even after removal of ZEBRA. Surprisingly, the regulatory phenomenon of synergy was manifested only when the concentration of TFIID was limiting. When the DA complex was saturating, transcription was not synergistic, as indicated by the ability of a single activator to induce isomerization effectively and turn on a gene. On the basis of these observations, we propose a new biochemical model for eukaryotic gene activation and synergy.

Combined effect of polystyrene microplastics and dibutyl phthalate on the microalgae Chlorella pyrenoidosa

The combined effect of polystyrene microplastics (mPS) and dibutyl phthalate (DBP), a common plastic additive, on the microalgae Chlorella pyrenoidosa was investigated in the present study. The 96 h-IC₅₀ value of DBP was 2.41 mg L^-1. Polystyrene microplastics exhibited size-dependent inhibitory effect to C. pyrenoidosa, with the 96 h-IC₅₀ at 6.90 and 7.19 mg L^-1 for 0.1 and 0.55 μm mPS respectively, but little toxicity was observed for 5 μm mPS. The interaction parameter ρ based on the response additive response surface (RARS) model varied from -0.309 to 5.845, indicating the interaction pattern varying with exposure concentrations of chemical mixtures. A modified RARS model (taking ρ as a function of exposure concentration) was constructed and could well predict the combined toxicity of mPS and DBP. More than 20% reduction of DBP was observed at 20 mg L^-1 mPS, while 1 mg L^-1 mPS had no significant effect on the bioavailability of DBP at different sampling time points. Volume, morphological complexity and chlorophyll fluorescence intensity of microalgal cells were disturbed by both DBP and mPS. The antagonistic effect of high concentrations of mPS might be partially attributed to the combination of hetero- and homo-aggregation and the reduced bioavailability of DBP. The overall findings of the present study profiled the combined toxic effects of mPS and DBP on marine phytoplankton species which will be helpful for further evaluation of ecological risks of mPS and DBP in marine environment.

Optic nerve head and nerve fiber layer in Alzheimer's disease

We compared (1) the differences in the retinal nerve fiber layer between 26 patients with Alzheimer's disease and 30 age- and race-matched normal controls with use of blue-light high-resolution photography, (2) the differences in disc pallor between 30 patients with Alzheimer's disease and 32 controls with use of a boundary-tracking program and fundus photographs, and (3) the topographic disc variables between 26 patients with Alzheimer's disease and 36 controls with use of an optic nerve head analyzer. A higher proportion of patients with Alzheimer's disease had detectable nerve fiber damage as seen by red-free photography compared with controls. Although the pallor area-to-disc area ratio was not significantly different between patients with Alzheimer's disease and controls, the patients with higher pallor area-to-disc area ratios had higher Alzheimer's Disease Assessment Scale (ADAS) scores and longer durations of disease. Patients had an increased cup-to-disc ratio and cup volume and decreased disc rim area compared with controls. These variables also correlated significantly with ADAS scores and the duration of disease. The correlation among the optic nerve head changes and the ADAS scores in patients with Alzheimer's disease suggests a potential role for optic nerve head analysis in monitoring the progression of Alzheimer's disease and in assessing the effectiveness of any treatments developed.

Healing of chondral and osteochondral defects in a canine model: the role of cultured chondrocytes in regeneration of articular cartilage

In this study a canine model was developed to investigate the nature of early healing responses to both chondral and osteochondral defects and to evaluate the tissue regenerative capacity of cultured autologous chondrocytes in chondral defects. The healing response to surgically created chondral defects was minor, with little cellular infiltration. In contrast, osteochondral defects exhibited a rapid cellular response, resulting ultimately in the formation of fibrous tissue. The lack of significant cellular activity in chondral defects suggests that an evaluation of the capacity of cultured autologous chondrocytes to regenerate articular cartilage is best studied in chondral defects using the canine model. When dedifferentiated cultured articular chondrocytes were implanted into chondral defects, islands of type II collagen staining were demonstrated in the regenerative tissue within 6 weeks. The relatively early expression of cartilage specific markers by the implanted chondrocytes, coupled with the inability of untreated chondral defects to repair or regenerate, demonstrates the utility of the canine model in evaluating novel materials for cartilage repair and regeneration.

Relationship between quality of life and occupational stress among teachers

OBJECTIVES

With major changes in the education system and limited resources supplied by the Government, Chinese teachers have been suffering from greater occupational stress in recent years, which is believed to affect their physical and mental health. The aim of this study was to explore the relationship between quality of life and occupational stress in primary and middle school teachers.

STUDY DESIGN

Originals.

METHODS

A cross-sectional study was conducted using cluster sampling. The study population was composed of 3570 school teachers working in 64 primary and middle schools in Heping District in Shenyang, China. A demographic questionnaire, the 36-item Short-Form Health Survey (SF-36) and the Occupational Stress Inventory Revised Edition were employed to collect demographic variables and assess quality of life and occupational stress. Multivariate stepwise linear regression analyses were performed to study the relationship between quality of life and occupational stress.

RESULTS

The mean scores for both male and female teachers in this study were significantly lower than those for the Chinese general population for all dimensions of quality of life, except mental health and vitality (P<0.05). Male teachers scored significantly higher than female teachers for physical functioning, bodily pain, vitality and physical health (P<0.05). Age, role overload, role insufficiency, vocational strain, psychological strain, physical strain, recreation and rational coping were significantly associated with both the physical and mental component summaries of the SF-36 (P<0.05). Gender, physical environment and self-care appeared to be robust indicators of physical health (P<0.05), while role insufficiency, interpersonal strain and social support were strong indicators of mental health (P<0.05).

CONCLUSIONS

In China, teachers have a lower health status than the general population. The quality of life of female teachers is worse than that of male teachers, and deteriorates with age. Occupational stress and strain induce worsening physical and mental conditions for teachers, while coping resources could promote their health. This study suggests that having adequate coping resources, especially social support, in workplaces may be an important factor for improving teachers' quality of life. Moreover, psychological interventions should be set up for teachers, and psychological counselling should be provided to relieve stress and enhance quality of life.

Ultrasound biomicroscopy in pseudophakic malignant glaucoma

BACKGROUND

Malignant glaucoma (ciliary block glaucoma; aqueous misdirection glaucoma) is an incompletely understood, rare and serious complication of intraocular surgery.

METHODS

A woman with pseudophakic malignant glaucoma underwent successful neodymium: YAG (Nd:YAG) laser photodisruption of the anterior hyaloid face with resolution of the glaucoma. High-resolution ultrasound biomicroscopy was used to image the anterior segment and anterior chamber angle before and after laser surgery.

RESULTS

Ultrasound biomicroscopy provided cross-sectional images of the iris, posterior chamber intraocular lens (IOL), and ciliary body and their relative positions before and after resolution of the malignant glaucoma. Anterior rotation of the ciliary body and anterior chamber shallowing normalized after rupture of the anterior hyaloid face.

CONCLUSION

High-resolution ultrasound biomicroscopy provided images consistent with accepted concepts of the pathophysiology of this disease and offers great promise for the future elucidation of the anatomic mechanisms underlying various forms of glaucoma.

Combined effect of polystyrene plastics and triphenyltin chloride on the green algae Chlorella pyrenoidosa

The combined effect of polystyrene (PS) particles and triphenyltin chloride (TPTCl) to the green algae Chlorella pyrenoidosa was studied. The 96 h IC₅₀ of TPTCl to the green algae C. pyrenoidosa was 30.64 μg/L. The toxicity of PS particles to C. pyrenoidosa was size-dependent, with the 96 h IC₅₀ at 9.10 mg/L for 0.55 μm PS but no toxicity observed for 5.0 μm PS. The exposure to 0.55 μm PS led to damage on structure of algal cells, which could in turn cause inhibition on photosynthesis and population growth of the green algae. TPTCl concentrations in test medium were lowered by 15-19% at presence of 0.55 μm PS particles, indicating a reduced bioavailability of TPTCl. In spite of this reduced bioavailability, the presence of PS increased the toxicity of TPTCl, which might be attributed to facilitated uptake of TPTCl by the green algae after the damage of cell structure. The overall results of the present study provided important information on the effect of PS on the bioavailability and toxicity of TPTCl to phytoplankton species.

Age-related decline of disc rim area in visually normal subjects

Optic disc parameters and axial lengths were measured in 81 visually normal young and elderly white adults (young [n = 41]: 27.2 +/- 5.7 years versus elderly [n = 40]: 68.8 +/- 8.4 years) using Rodenstock Optic Disc Analyzer and A-scan sonography. Axial lengths correlated positively with optic disc parameters (Spearman correlation analysis: rim area: P = 0.042, disc area: P = 0.052, and cup volume: P = 0.010). Older subjects had a shorter axial length (23.09 +/- 1.02 mm) and smaller disc rim area (1.171 +/- 0.338 mm2) than younger subjects (23.60 +/- 1.15 mm and 1.325 +/- 0.314 mm2; Mann-Whitney U test: P = 0.011 and P = 0.013, respectively). While both axial length and disc rim area declined with age (0.011 mm and 0.003 mm2 per year; Spearman correlation analysis: P = 0.032 and P = 0.020, respectively), the cup-to-disc and rim area-to-disc area ratios appeared to remain relatively constant throughout adult life. The age-related decline of disc rim area is consistent with histologic evidence of age-related decline of ganglion cell axons. The rim area-to-disc area ratio seems less affected by age, and is thus a better parameter to isolate age-related change from disease-related change of optic nerve in a longitudinal follow-up of diseases involving the optic nerve head.

The ZEBRA activation domain: modular organization and mechanism of action

An RNA polymerase II activator often contains several regions that contribute to its potency, an organization ostensibly analogous to the modular architecture of promoters and enhancers. The regulatory significance of this parallel organization has not been systematically explored. We considered this problem by examining the activation domain of the Epstein-Barr virus transactivator ZEBRA. We performed our experiments in vitro so that the activator concentrations, stabilities, and affinities for DNA could be monitored. ZEBRA and various amino-terminal deletion derivatives, expressed in and purified from Escherichia coli, were assayed in a HeLa cell nuclear extract for the ability to activate model reporter templates bearing one, three, five, and seven upstream ZEBRA binding sites. Our data show that ZEBRA contains four modules that contribute to its potency in vitro. The modules operate interchangeably with promoter sites to determine the transcriptional response such that the loss of modules can be compensated for by increasing promoter sites. Potassium permanganate footprinting was used to show that transcriptional stimulation is a consequence of the activator's ability to promote preinitiation complex assembly. Kinetic measurements of transcription complex assembly in a reconstituted system indicate that ZEBRA promotes formation of a subcomplex requiring the TFIIA and TFIID fractions, where TFIIA acts as an antirepressor. We propose a model in which the concentration of DNA-bound activation modules in the vicinity of the gene initiates synergistic transcription complex assembly.

The effect of polystyrene plastics on the toxicity of triphenyltin to the marine diatom Skeletonema costatum-influence of plastic particle size

The effect of polystyrene (PS) particles on the toxicity of triphenyltin (TPT) to the marine diatom Skeletonema costatum was investigated. The 0.1-μm PS particles attached to the cell walls of S. costatum but did not cause adverse effects on the growth of the diatom. The adsorption of TPT to PS particles was negligible in seawater systems, but the presence of 0.1-μm PS significantly reduced the bioavailable concentrations of TPT in f/2-Si medium, indicating a potential three-way interaction between TPT, PS particles, and components of f/2-Si medium. The adsorption of TPT to PS of smaller size (i.e., 0.1 μm) was stronger than that of PS of larger size (i.e., 5 μm), which was probably attributed to larger surface areas of smaller PS particles. The presence of PS could reduce the toxicity of TPT. IC₅₀ values of TPT increased from 0.56 to 0.85 and 0.71 μg/L at the presence of 20 mg/L 0.1-μm PS and 5-μm PS, respectively. The overall results of this study profiled the combined toxic effects of PS and TPT on marine phytoplankton species and highlighted the difference in adsorption of organic pollutants by microplastics in different ambient mediums.

Factors associated with occupational strain among Chinese teachers: a cross-sectional study

OBJECTIVES

With the reform of the education system in China, teachers are suffering from more occupational strain, which is believed to impair their working state indirectly and affect their health. This study assessed occupational strain and explored the related factors among Chinese teachers.

STUDY DESIGN

Cross-sectional with cluster sampling.

METHODS

The study population was composed of 3570 school teachers working in 64 primary and middle schools in Heping District in Shenyang, China. Data were collected using a self-administered questionnaire (the Chinese version of the Occupational Stress Inventory scale). Multivariate linear regression analyses were performed to study the factors related to occupational strain.

RESULTS

The average score on the Personal Strain Questionnaire (PSQ) for the whole study population was 106.5 (107.5 in men and 106.3 in women). Teachers with chronic disease, a greater number of days of sick leave, recent experience of a stressful life event and divorced/separated/widowed status tended to suffer greater strain than their peers. Regression analyses showed that the PSQ score was significantly associated with role overload, role boundary, responsibility and physical environment, and inversely associated with recreation and rational coping. The most crucial predictors of occupational strain were chronic disease, days of sick leave, recent experience of a stressful life event and marital status. Being a class teacher was the strongest indicator of interpersonal strain. Self-care was associated with vocational strain and psychological strain, and inversely associated with physical strain.

CONCLUSIONS

Most teachers in this study experienced a high degree of occupational strain. Chronic disease, days of sick leave, recent experience of a stressful life event and divorced/separated/widowed status played prominent roles in occupational strain. In addition, role overload, role boundary, responsibility and physical environment induce occupational strain, while recreation and rational coping have a positive effect on occupational strain. Interventions such as proper management of chronic diseases and establishment of a balanced work-family life are crucial to reduce occupational strain. Recreation and training in coping abilities are needed to enhance positive working environments and attenuate the occupational strain imposed on teachers.

Comparing regions of the Epstein-Barr virus ZEBRA protein which function as transcriptional activating sequences in Saccharomyces cerevisiae and in B cells

The ZEBRA protein activates expression of Epstein-Barr virus early-lytic-cycle genes in human B lymphocytes. Here it is shown that ZEBRA also behaves as a sequence-specific transcriptional activator in Saccharomyces cerevisiae. Deletional mutagenesis defined three regions of ZEBRA that participate in activation in S. cerevisiae. These regions are designated YI (amino acids [aa] 1 to 25), YII (aa 51 to 102), and YIII (aa 228 to 245). Two of the three regions of the native ZEBRA protein act together to mediate activation when assayed on ZEBRA binding sites. However, when fused to the DNA binding domain of GAL4 and assayed on GAL4 binding sites, regions YII and YIII were each sufficient to confer activation in S. cerevisiae. Regions of ZEBRA which affected activation in S. cerevisiae were also required in human B lymphocytes. The amino-terminal region of ZEBRA (aa 1 to 98) was required for activation both in S. cerevisiae and in human B cells; deletion of the carboxy-terminal 18 aa also significantly reduced activation in both cell types. Thus, the behavior of ZEBRA in human B cells and S. cerevisiae suggests that the protein contains universal activation motifs that interact with conserved components of the transcription machinery. However, certain deletion mutants of ZEBRA containing mutations in the N-terminal region exhibited discordant behaviors in S. cerevisiae and in B cells. For example, deletion of ZEBRA aa 26 to 51 impaired activation to a great extent in B cells but had little or no effect in S. cerevisiae. The discordant mutants may reflect interactions with a variable domain of a conserved component or unique interactions with specialized components of the basal transcription apparatus in different cells.

Ozone oxidation of 2,4,6-TCP in the presence of halide ions: Kinetics, degradation pathways and toxicity evaluation

2,4,6-Trichlorophenol (2,4,6-TCP) is extensively consumed in industrial production and may cause environmental damages. The effect of halide ions on the decomposition of 2,4,6-TCP has often been overlooked. In this study, the bromide ion was found to have a stronger negative impact on 2,4,6-TCP degradation than chloride ion in the O₃ system, and led to the formation of adsorbable organic halogens (AOX). Kinetic modeling demonstrated that the concentration of various radicals was largely depended on the solution pH, and stronger basicity not only contributed to the mineralization of 2,4,6-TCP, but also inhibited the formation of halogenated by-products. Combining the intermediate identification and quantum chemical calculation, the degradation pathways of 2,4,6-TCP during ozone oxidation process were proposed. The toxicity test and ECOSAR simulation demonstrated that the acute toxicity of some 2,4,6-TCP degradation intermediates was relatively higher than their parent compound. With high concentrations of halide ions, the ozone-treated solution showed greater toxicity than the originator 2,4,6-TCP solution. These results illustrate that the ozone treatment of the halide-containing wastewater may cause potential ecological hazards and its application needs to be more cautious.

Effect of nano zinc oxide on the acute and reproductive toxicity of cadmium and lead to the marine copepod Tigriopus japonicus

Given the absorbability of nZnO and its inevitable coexistence with trace metals such as Cd and Pb in coastal environment, nZnO can adsorb these pollutants thereby affecting their distribution in different media of marine ecosystem. The marine copepod Tigriopus japonicus was applied in the present study to investigate the combined effect of nZnO and Cd or Pb on mortality and reproduction in marine organisms. For acute exposure, presence of 1.0 mg/L nZnO increased the toxicity of both Cd and Pb, as their LC₅₀ decreased from 5.9 and 75.4 mg/L to 3.95 and 48.0 mg/L, respectively. For 21 d chronic exposure, the reproduction of the copepod was influenced by Cd and Pb at environmental relevant concentrations, and the interaction between nZnO and Cd or Pb appeared to be antagonistic. The waterborne Cd and Pb concentration was affected by nZnO for neither acute nor chronic exposure, indicating no adsorption of these two metals to nZnO at relative low concentration. The overall findings of this study suggested the binary exposure to nZnO/Cd or nZnO/Pb might have potential different toxic mechanisms between acute and chronic exposure.

Toxic effect of triphenyltin in the presence of nano zinc oxide to marine copepod Tigriopus japonicus

Marine organisms are naturally exposed to different environmental pollutants including organic pollutants and nanoparticles. The interactive effects between nanoparticles and other chemicals on aquatic organisms have raised concerns regarding the potential of nanomaterials as the vector for other chemicals. In the present study, the effect of nano zinc oxide (nZnO) on the bioavailability of triphenyltin chloride (TPTCl) was studied, and their combined acute and reproductive toxicity to the marine copepod Tigriopus japonicus were evaluated. At experimental concentration ranges of nZnO in this study, the percentage of dissolution of Zn²⁺ was relative stable (from 62% to 66%), and nZnO did not affect the bioavailability of TPTCl to the copepods. The acute toxicity of binary mixtures of nZnO/TPT was equivalent to that of the mixture of Zn²⁺/TPT. In agreement with the decrease in TPTCl's LC₅₀ values at the presence of nZnO, their interacting effect was synergistic based on response addition response surface model, and the interacting parameter was modelled to be -1.43. In addition to acute toxicity test, reproductive toxicity tests revealed that exposure to nZnO and TPTCl didn't affect the successful mating rate and the number of nauplii in the 1st brood, but they extended the time for the eggs to hatch from 2.53 days to 3.94 and 3.64 days, respectively. The exposure to nZnO/TPTCl mixture delayed the time to hatch to 5.78 days.