Effect of atmospheric pressure non-thermal pin to plate plasma on the functional, rheological, thermal, and morphological properties of mango seed kernel starch.

This study aimed to investigate the effect of atmospheric pressure non-thermal pin-to-plate plasma on the functional, rheological, thermal, and morphological properties of mango seed kernel starch. As cold plasma contains highly reactive species and free radicals, it is expected to cause noticeable modifications in the attributes of starch treated. The isolated mango seed kernel starch was subjected to the plasma treatment of input voltages 170 and 230 V for 15 and 30 min of exposure. Water adsorption, swelling, and solubility at lower temperatures. There has been a significant reduction (p < 0.05) in pH values of starch from 7.09 to 6.16 and also the desirable reduction in turbidity values by 42.60%. However, there has been no significant change in the oil and water binding behavior of the starch. The FTIR spectra of MSKS demonstrate the formation of amines which contributes to the better hydrophilic nature of the starch. The structural modification has been adequately confirmed by SEM images. The maximum voltage and time combination, lead to depolymerization of starch which is supported by NMR spectra thus affecting thermal and rheological properties. The application of cold plasma-modified MSKS in food would facilitate stable and smooth textural development.

An analysis of the biopharmaceutical behaviour of proton pump inhibitors with different physicochemical properties.

At present, little information on the biopharmaceutical behaviour of proton pump inhibitors (PPIs) describing their absorption and biodistribution in vivo has been reported because the extreme instability of PPIs in the gastrointestinal environment makes it difficult to analyze such behaviour. In this work, a modified rat in situ intestinal perfusion model was employed to investigate absorption in the gastrointestinal tract and subsequent biodistribution of several PPIs (ilaprazole, esomeprazole and rabeprazole), which have different physicochemical properties. Our data indicated that PPIs exhibited significantly enhanced absorption rates in the whole intestine, including the duodenum, jejunum, ileum and colon, corresponding to the increase in the oil-water partition coefficient (LogP). PPIs and corresponding salt types showed no obvious differences in absorption, implying that solubility changes in the PPI have little effect on its absorption in the gastrointestinal tract. Among these PPIs, ilaprazole presented a more stable intestinal absorption behaviour, as well as more distribution and longer residence time in the stomach by HPLC-MS/MS analysis and radioactivity counts after 14C radiolabelling. These results may be useful information for PPI optimization and oral formulation design.

Influences of Molecular Weights on Physicochemical and Biological Properties of Collagen-Alginate Scaffolds.

For tissue engineering applications, biodegradable scaffolds containing high molecular weights (MW) of collagen and sodium alginate have been developed and characterized. However, the properties of low MW collagen-based scaffolds have not been studied in previous research. This work examined the distinctive properties of low MW collagen-based scaffolds with alginate unmodified and modified by subcritical water. Besides, we developed a facile method to cross-link water-soluble scaffolds using glutaraldehyde in an aqueous ethanol solution. The prepared cross-linked scaffolds showed good structural properties with high porosity (~93%) and high cross-linking degree (50-60%). Compared with collagen (6000 Da)-based scaffolds, collagen (25,000 Da)-based scaffolds exhibited higher stability against collagenase degradation and lower weight loss in phosphate buffer pH 7.4. Collagen (25,000 Da)-based scaffolds with modified alginate tended to improve antioxidant capacity compared with scaffolds containing unmodified alginate. Interestingly, in vitro coagulant activity assay demonstrated that collagen (25,000 Da)-based scaffolds with modified alginate (C25-A63 and C25-A21) significantly reduced the clotting time of human plasma compared with scaffolds consisting of unmodified alginate. Although some further investigations need to be done, collagen (25,000 Da)-based scaffolds with modified alginate should be considered as a potential candidate for tissue engineering applications.

Mixed-monolayer functionalized gold nanoparticles for cancer treatment: Atomistic molecular dynamics simulations study.

Gold nanoparticles (AuNPs) are employed as drug carriers due to their inertness, non-toxicity, and ease of synthesis. An experimental search for the optimal AuNP design would require a systematic variation of physico-chemical properties which is time-consuming and expensive. Computational methods provide quicker and cheaper approach to complement experiments and provide useful guidelines. In this paper, we performed atomistic molecular dynamics simulations to study how the size, hydrophobicity, and concentration of the drug affect the structure of functionalized AuNPs in the aqueous environment. We simulated two groups of nano-systems functionalized with a zwitterionic background ligand, and a ligand carrying a drug (Quinolinol or Panobinostat). Results indicate that in the case of a hydrophobic drug (Quinolinol), the hydrophobicity drives the conformation changes of the coating layer. The tendency of the hydrophobic drug to reduce its solvent-accessible surface results in a decrease of the coating thickness and the overall NP size. Although the amount of accessible drug can be increased by increasing its initial concentration, it will compromise the solubility of the system. In the case of a hydrophilic drug (Panobinostat), the ligand in excess has a dominant influence on the final structure of the coating conformations. The percentage of accessible drug is significantly higher than in the hydrophobic systems for any given ratio. It implies that for hydrophilic systems we can generally expect higher biological efficiency. Our results highlight the importance of taking into account physico-chemical properties of drugs and ligands when developing gold-based nanosystems, especially in the case of hydrophobic drugs.

Efficacy of postharvest sodium nitroprusside application to extend storability by regulating physico-chemical quality of pear fruit.

Quality loss in pear fruit during storage reduces its marketability for long run. To increase its storability, the efficacy of postharvest dip treatment donor sodium nitroprusside (SNP) 0.000, 0.001, 0.002 and 0.003 mol L-1 were investigated on pear fruit cv. Patharnakh under storage conditions (low temperature 0-1 °C and relative humidity (90-95%). SNP effectively lowered fruit mass loss, retained colour and higher firmness, suppressed browning and respiration rate and sustained soluble solids content, titratable acidity, total phenol content and ascorbic acid thus conserved the fruit quality for longer period. SNP treatments suppressed the activity of polyphenol oxidase and increased activity of superoxide dismutase enzyme. Additionally, the SNP treated fruit exhibited lesser activities of fruit softening enzymes like pectin methylesterase, polygalacturonase and cellulase. Among all, 0.002 mol L-1 SNP concentration was superior to lengthen storability and sensory quality of pear up to 60 d under cold storage.

Evaluation studies on effects of quercetin with different concentrations on the physicochemical properties and in vitro digestibility of Tartary buckwheat starch.

The effects of polyphenols on the physicochemical properties and in vitro digestibility of Tartary buckwheat starch (TBS) remain scarce. In this study, the rheological, thermal properties, and in vitro digestibility of pregelatinized TBS (pre-TBS) with quercetin complexation at various concentrations were characterized. It was found that quercetin complexation increased the shearing resistance and viscosity of pre-TBS. Both SEM and TGA results revealed a more compact and stable structure of starch-quercetin complex in comparison to pre-TBS. The non-inclusive complex with higher crystallinity was formed through hydrogen bonds, which showed by XRD and FT-IR results. Additionally, complexes exhibited the lower digestion rate and digestion velocity constant, and the resistant starch content of complex (with 10% quercetin addition) was the highest. Therefore, quercetin complexation could improve the thermal and rheological properties, and decrease in vitro digestibility of pre-TBS, which could provide a theoretical basis for functional food development.

Preformulation studies of l-glutathione: physicochemical properties, degradation kinetics, and in vitro cytotoxicity investigations.

Objectives: l-Glutathione (GSH) is an endogenous tripeptide with super antioxidant properties. In this study, preformulation parameters of GSH and its degradation products were fully investigated.Significance: To date, no experimental preformulation data is available for GSH. Therefore, to the author's knowledge, this is the first study to experimentally determine the preformulation parameters of GSH, which can be considered more reliable for further studies.Methods: An HPLC method for GSH was optimized and validated to accurately quantify the GSH amount in solution, used to investigate GSH's solubility and Log P. Differential Scanning Calorimeter and Thermogravimetric Analyzer were used to evaluate the thermal properties of GSH. Polarized microscope and Fourier-transform Infrared Spectroscopy were used to determine GSH's crystal habits and functional groups, respectively. Forced degradation kinetics and the degradation products were investigated and identified by LC-MS, respectively. GSH's cellular cytotoxicity on fibroblasts was investigated by MTT assay.Results: It was determined that GSH has high aqueous solubility (252.7 mg/mL), low Log P (-3.1), a melting endotherm of 195 °C and decomposition at 210°C, negligible moisture content, and a rectangular/cylindrical-shaped crystalline form. Seven degradation products were identified; one of the major degradation products of GSH under different conditions is first order kinetic oxidation into glutathione disulfide. No cytotoxicity was observed when fibroblasts were treated with GSH (0.005-10.000 mg/mL).Conclusions: Precise preformulation parameters of GSH were obtained, and these are imperative for the development and optimization of advanced GSH formulations.

Quantitatively Fine-Tuning the Physicochemical and Biological Properties of Peptidic Polymers through Monodisperse PEGylation.

In biomedicine, PEGylation is one of the most successful strategies to modify the physicochemical and biological properties of peptides, proteins, and other biomacromolecules. Because of the polydisperse nature of regular PEGs and limited PEGylation strategies, it is challenging to quantitatively fine-tune and accurately predict the properties of biomacromolecules after PEGylation. However, such fine-tuning and prediction may be crucial for their biomedical applications. Herein, some monodisperse PEGylation strategies, including backbone PEGylation, side-chain PEGylation, and highly branched PEGylation, have been developed. In a comparative fashion, the impact of PEGylation strategies and monodisperse PEG sizes on the physicochemical and biological properties, including lipophilicity, thermosensitivity, biocompatibility, plasma stability, and drug delivery capability, of peptidic polymers has been quantitatively studied. It was found that the physicochemical and biological properties of PEGylated peptidic polymers can be quantitatively fine-tuned and accurately predicted through these monodisperse PEGylation strategies. After the comparative study, a side-chain monodisperse PEGylated peptidic polymer was chosen as fluorine-19 magnetic resonance and fluorescence dual-imaging traceable drug delivery vehicle. Our study may not only promote the transformation of PEGylation from an empirical technology to a quantitative science but also shed light on the rational design of PEGylated biomaterials and pharmaceutics.

Impacts on soil microbial characteristics and their restorability with different soil disinfestation approaches in intensively cropped greenhouse soils.

The different impacts, especially on soil physicochemical and microbial characteristics, among disinfestation methods based on different principles (including physical, chemical, and biological) have not been illustrated well. Here, we used steam sterilization, dazomet fumigation, and reductive soil disinfestation (RSD) methods representative of physical, chemical, and biological soil disinfestation, respectively, to disinfest seriously degraded greenhouse soils before watermelon cultivation in one season. Compared with the control, RSD significantly decreased the soil nitrate content by 85.9% and the electrical conductivity by 52.0% and increased the soil pH to 7.44. Although all three soil disinfestations significantly decreased the abundance of the pathogen Fusarium oxysporum by 83.0-99.2%, their impacts on soil microbial characteristics were variable. Briefly, steam sterilization significantly changed multiple bacterial and fungal properties. Dazomet fumigation impacted mainly fungal properties, such as abundance, diversity, and community structure, but RSD significantly decreased bacterial diversity and altered the bacterial community structure. Although the differences mentioned above got smaller after watermelon cultivation, the plant performances differed dramatically in different soils. The largest plant biomass, fruit ratio, and yield were found in the RSD-treated soil, whereas the lowest fruit ratio and yield were found in the steam-sterilized soil. The soil nitrate content, electrical conductivity, bacterial diversity and community structure, and some specific microbial agents, such as Aspergillus, Cladosporium, and Pseudomonas, were correlated with plant performance. RSD is a promising soil disinfestation strategy to support plant growth in intensively cultivated greenhouse soils with serious problems, such as acidification, salinization, and pathogen accumulation.

Discovery of anti-mucoviscous activity of rifampicin and its potential as a candidate antivirulence agent against hypervirulent Klebsiella pneumoniae.

A recent increase in the incidence of hypervirulent Klebsiella pneumoniae (hvKP) infections, especially those caused by a sublineage of clonal group CG23 (CG23-I), is raising serious health concerns worldwide. The high virulence of hvKP is, at least in part, attributed to the overproduction of capsular polysaccharide (CPS), which is triggered by a positive regulator of capsular polysaccharide synthesis (cps) genes, named rmpA (regulator of mucoid phenotype A). Although extensive research has been conducted on the mechanisms of hvKP virulence, no study has focused on the development of antivirulence therapeutics. This study attempted to identify and validate an antimicrobial agent able to suppress hvKP hypermucoviscosity. A total of 18 commercially available antimicrobial agents, including ß-lactams, quinolones and aminoglycosides, were tested. Rifampicin (RFP) was found to have strong anti-mucoviscous activity against CG23-I hvKP even at subinhibitory concentrations. Polysaccharide extracts from hvKP showed substantially lowered viscosity when cells were grown with RFP. Moreover, microscopic observations demonstrated that RFP treatment results in a drastic reduction in the thickness of the CPS layer around hvKP cells. RFP treatment decreased transcript levels of rmpA and rmpA-regulated cps genes, indicating that RFP suppresses mucoviscosity of hvKP through inhibition of rmpA transcription. These data suggest that RFP may serve as a potential antivirulence agent for refractory hvKP infection.

Effect of NaCl on physicochemical properties of xanthan gum - Water chestnut starch complexes.

Pasting and functional properties of water chestnut starch (WCS) alone and mixture of WCS and xanthan gum (XG) were determined by addition of NaCl (0.5, 1, and 2%) at fixed water chestnut starch (5%) and xanthan gum (0.3%) concentration. Results indicated that presence of NaCl had a significant impact on functional and pasting properties of both WCS alone and WCS - XG mixture. Pasting temperature of WCS and WCS - XG mixture increased linearly with increasing salt content, whereas a reverse trend was observed in peak viscosity and sets back in case of WCS alone. It was found that addition of NaCl decreased the swelling power of WCS alone, while it increased in case of WCS - XG mixture. The water absorption of WCS - XG improved drastically by the addition of NaCl while a rapid decline in syneresis was observed with WCS - XG mixture. The transparency of both WCS and WCS - XG mixture were found to be increased after the addition of NaCl.

Drug delivery of rifampicin by natural micelles based on inulin: Physicochemical properties, antibacterial activity and human macrophages uptake.

This work aims at designing a drug delivery system for rifampicin (RIF) to be used for the therapy of infections from mycobacterium tuberculosis or other lung-colonizing bacteria. We are proposing, in particular, the delivery of RIF by micelles based on inulin functionalized with vitamin E (INVITE). We previously demonstrated that INVITE micelles are formed from the self-assembling sustained by the interaction, within the hydrophobic core, of aromatic groups belonging to vitamin E. It points on the effectiveness of these biocompatible systems in incorporating aromatic-group-bearing hydrophobic drug such as RIF. The succinilated derivative of INVITE, namely INVITESA, was further studied. Other than a full physicochemical characterization, the obtained micelles containing RIF were tested for their antibacterial activity against Gram- or Gram+bacteria including mycobacterium smegmatis. Furthermore, uptake studies on human alveolar macrophages and MTT studies were performed.

The optimization of prebiotic sucrose-free mango nectar by response surface methodology: The effect of stevia and inulin on physicochemical and rheological properties.

The reduction of sugar consumption is one of the major challenges for nutritionists and food industry. Therefore, it is significant to replace sucrose with other types of sweeteners, especially, natural ones. The aim of the present study is to produce low-calorie, sucrose-free mango nectar and to optimize the formulation by employing response surface methodology. The two independent variables were stevia, as a low-calorie sugar replacer (0, 1.5, and 3% w/w) and inulin as a prebiotic texturizer (0, 3, and 6% w/w) in order to compensate sugar elimination defect on viscosity and °Brix. The fitted models indicated a high coefficient of determination. The results revealed that stevia and inulin are as the independent variables which had significant effects on °Brix, viscosity, and sensory scores (p < 0.05). Also, pH was affected by stevia concentration. The rheological behavior of the sucrose-free mango nectar was non-Newtonian, shear thinning as Herschel-Bulkley model which was not different from the reported behavior for normal mango nectar-containing sucrose. The optimization of the variables, based on the response surface three-dimensional plots, demonstrated that utilizing 6% w/w inulin and 3% w/w stevia produced the optimum mango nectar with the desirability of 0.85 without undesirable changes in the physicochemical and organoleptic properties. The optimum sample was produced in triplicate to validate the optimum model as well.

Antiproliferative Effect of Urera baccifera Leaves Against Ovarian Carcinoma Cell Line (OVCAR-3)

Abstract Natural products, especially phytochemicals, have been extensively studies and have exhibited important antiproliferative effects. The American native species Urera baccifera (L.) Gaudich. ex Wedd. (Urticaceae) is widely distributed in Brazil, where it is known as urtiga-vermelha or urtigão. The leaves are popularly used as anti-inflammatory, antirheumatic and in the treatment of gastric disorders. However, the antiproliferative potential of this plant against human tumor cells remain to be elucidated. In this study, we evaluated the antiproliferative effects of U. baccifera leaves extracts and fractions against a panel of human tumor cell lines in vitro besides a chemical evaluation of the most active sample by mass spectrometry (ESI-IT-MSn). The hydroalcoholic extract was inactive while dichloromethane extract showed moderate cytostatic activity against ovarian carcinoma cell line (OVCAR-3, GI50 = 1.5 μg/mL). More, the ethyl acetate and n-butanol fractions did not show important activity against tumour cell while the dichloromethane and hexane fractions showed moderate cytostatic activity against ovarian tumor cell line (OVCAR-3, GI50 = 12.7 and 9.4 μg/mL, respectively). Finally, the chemical profile evaluated by mass spectrometry (ESI-IT-MSn) allowed the detection of flavonoids in the HEU and hydroxylated fatty acid in DEU that can explain partially the biological effects observed. This is the first report of the antiproliferative effects of U. baccifera, and DEU has shown potential as a promising source of bioactive compounds.

Chlorhexidine-encapsulated mesoporous silica-modified dentin adhesive.

OBJECTIVES: This work aims to explore the feasibility of chlorhexidine-encapsulated mesoporous silica (CHX@pMSN) as a modifier of a commercial dental adhesive via the evaluation of physicochemical properties and antibacterial capabilities of adhesive-dentin interface. METHODS: Therapeutic adhesives were developed in the present study by incorporating CHX@pMSN into a commercial adhesive at four mass fractions (0, 1, 5 and 10 wt.%). The antibacterial capability on Streptococcus mutans (S. mutans) biofilm, conversion degree, adhesive morphology, microtensile bond strength (MTBS) and nanoleakage expression were evaluated comprehensively. RESULTS: MTT and CLSM evaluation showed that CHX@pMSN-doped adhesive inhibits S. mutans biofilm growth, while CHX is released from the modified adhesive continuously. The incorporation of CHX@pMSN did not affect immediate bond strength at the concentration of 1% and 5% (P > 0.05). Moreover, these bonds were mainly preserved in 5% CHX@pMSN group after one month of collagenase ageing. Meanwhile, CHX@pMSN-doped adhesive groups exhibited similar nanoleakage distribution compared with the control. CONCLUSION: This study showed that the 5% CHX@pMSN-modified adhesive achieved balance amongst unaffected immediate bonding strength, well-preserved bonds against collagenase ageing and effective inhibition of S. mutans biofilm growth. CLINICAL SIGNIFICANCE: CHX@pMSN-modified dentin adhesive can potentially extend the service life of adhesive restoration in clinic.

Assessment of Douro and Ave River (Portugal) lower basin water quality focusing on physicochemical and trace element spatiotemporal changes.

Water quality of Douro and Ave lower basin was evaluated regarding physicochemical parameters (pH, conductivity, dissolved oxygen and temperature), nutrient compounds (nitrates, nitrites, ammonium and orthophosphates), chlorophyll a and occurrence of trace elements (Li, Be, Al, Ti, V, Cr, Co, Ni, Cu, Zn, Se, Mo, Ag, Cd, Sb, Ba, Tl, Pb, Th and U). To study spatiotemporal variations and possible anthropogenic sources, estuarine samples were collected at nine sampling sites in Douro and five in Ave distributed along the estuaries at four sampling campaigns (spring, summer, fall and winter). According to the water quality standards for aquatic life and recreation, Douro and Ave river water quality was found out of safe limits regarding several parameters. Nitrate levels were systematically high (> 50 mg L-1 in a significant number of samples) and mean levels of trace elements were higher than the established values of Canadian Environmental Quality Guidelines for aquatic life protection for Al, Cu, Se, Ag, Cd and Pb in Douro and Ave, and also Zn in Ave. Significant spatial differences were found in Ave river estuary for trace elements with a clear trend for higher values from upstream to downstream found. Seasonal differences were also observed particularly in Douro river estuary with higher levels in spring for most elements.

The enhanced biomass and lipid accumulation in Coccomyxa subellipsoidea with an integrated treatment strategy initiated by brewery effluent and phytohormones.

Brewery effluent (BE) as an appreciable and sustainable resource presented new possibilities in low-cost algal biomass production, whereas the relatively low essential macronutrients hindered extensive applications as growth medium for microalgae cultivation. The objective of this study was to investigate the feasibility of an integrated treatment strategy initiated by BE coupling phytohormones in augmenting biomass and lipid accumulation in Coccomyxa subellipsoidea. Results revealed that BE coupling synthetic 1-naphthaleneacetic acid (NAA) accomplished the favorable lipid productivity of 481.76 mg/L/days, representing 6.80- to 9.71-fold more than that of single BE as well as standard Basal media. BE coupling NAA feeding also heightened the proportions of C16-C18 fatty acids (over 96%) and mono-unsaturated C18:1 (approximate 45%) which were prone to high-quality biofuels-making. Such profound lipids accumulation might be attributable to that BE coupling NAA treatment drove most of metabolic flux (i.e. acetyl-CoA) derived from TCA cycle and glycolysis flowing into lipid accumulation pathway. Concurrently, the complete removal of total nitrogen and total phosphorus by C. subellipsoidea with assistance of NAA were easily complied with the permissible dischargeable limits for BE. These present results strongly demonstrated that BE coupling NAA was a potential feeding strategy in boosting algal lipid productivity and further provided great possibilities in linking affordable algal biomass production with high-efficient biological contaminants removal.

Effects of lipid formulations on clove extract spray dried powders: comparison of physicochemical properties, storage stability and in vitro intestinal permeation.

Clove is an aromatic plant spice with potent antioxidant and anti-inflammatory activity. Eugenol is the main compound which contributes to such medicinal and nutritional benefits. To date, the formulation of unstable, volatile and poorly water-soluble compounds remains a challenging task. Lipid formulations can be used to improve physicochemical and biopharmaceutical properties of poorly soluble compounds. The aim of this study is to investigate the effects of lipids, such as Gelucire and Compritol on physicochemical properties; stability and in vitro intestinal permeation of spray dried powdered formulations loaded with clove's bioactive compounds. Results showed that eugenol retention in spray-dried powders could be correlated with antioxidant activity and with mass recovery after spray drying. Adding Gelucire but not Compritol to clove extract formulations, improved solubility of spray dried powders. Stability test in high humidity environment (63.5% RH) suggested that formulations including both Gelucire and Compritol were significantly more stable compared to the formulation without any lipid at the two tested temperatures (25 °C and 40 °C). This suggests that lipid additions to clove (Syzygium aromaticum) extract formulations provide protective effects for the spray dried powders in high-humidity environments. In addition, results from in vitro intestinal permeation studies suggested that eugenol uptake, was not being hindered by transporters nor was the absorption being affected by lipid formulations.

Effects of simultaneously elevated temperature and CO2 levels on Nicotiana benthamiana and its infection by different positive-sense RNA viruses are cumulative and virus type-specific.

We have studied how simultaneously elevated temperature and CO2 levels [climate change-related conditions (CCC) of 30°C, 970 parts-per-million (ppm) of CO2 vs. standard conditions (SC) of 25°C, ~ 405ppm CO2] affect physiochemical properties of Nicotiana benthamiana leaves, and also its infection by several positive-sense RNA viruses. In previous works we had studied effects of elevated temperature, CO2 levels separately. Under CCC, leaves of healthy plants almost doubled their area relative to SC but contained less protein/unit-of-area, similarly to what we had found under conditions of elevated CO2 alone. CCC also affected the sizes/numbers of different foliar cell types differently. Under CCC, infection outcomes in titers and symptoms were virus type-specific, broadly similar to those observed under elevated temperature alone. Under either condition, infections did not significantly alter the protein content of leaf discs. Therefore, effects of elevated temperature and CO2 combined on properties of the pathosystems studied were overall cumulative.

Influences of temperature and salinity on physicochemical properties and toxicity of zinc oxide nanoparticles to the marine diatom Thalassiosira pseudonana.

Climate change is predicted to result in rising average temperature of seawater with more extreme thermal events, and frequent rainfalls in some coastal regions. It is imperative to understand how naturally mediated changes in temperature and salinity can modulate toxicity of chemical contaminants to marine life. Thus, this study investigated combined effects of temperature and salinity on toxicity of zinc oxide nanoparticles (ZnO-NPs) to the marine diatom Thalassiosira pseudonana. Because ZnO-NPs formed larger aggregations and released less zinc ions (Zn2+) at greater temperature and salinity, toxicity of ZnO-NPs to T. pseudonana was less at 25 °C than at 10 °C and less at 32 than 12 PSU. However, toxicity of ZnO-NPs was significantly greater at 30 °C, since T. pseudonana was near its upper thermal limit. Three test compounds, ZnO, ZnO-NPs and ZnSO4, displayed different toxic potencies and resulted in different profiles of expression of genes in T. pseudonana. This indicated that ZnO-NPs caused toxicity via different pathways compared to ZnSO4. Mechanisms of toxic action of the three compounds were also dependent on temperature and salinity. These results provide insights into molecular mechanisms underlying the responses of the diatom to ZnO-NPs and Zn2+ under various regimes of temperature and salinity.