Plastic breath: Quantification of microplastics and polymer additives in airborne particles.

The widespread extensive use of synthetic polymers has led to a substantial environmental crisis caused by plastic pollution, with microplastics detected in various environments and posing risks to both human health and ecosystems. The possibility of plastic fragments to be dispersed in the air as particles and inhaled by humans may cause damage to the respiratory and other body systems. Therefore, there is a particular need to study microplastics as air pollutants. In this study, we tested a combination of analytical pyrolysis, gas chromatography-mass spectrometry, and gas and liquid chromatography-mass spectrometry to identify and quantify both microplastics and their additives in airborne particulate matter and settled dust within a workplace environment: a WEEE treatment plant. Using this combined approach, we were able to accurately quantify ten synthetic polymers and eight classes of polymer additives. The identified additives include phthalates, adipates, citrates, sebacates, trimellitates, benzoates, organophosphates, and newly developed brominated flame retardants.

Studies of Potential Migration of Hazardous Chemicals from Sustainable Food Contact Materials.

In recent years, due to modern techniques for the distribution, transport, and retail sale of food, the production of large amounts of non-biodegradable and bioaccumulative packaging waste has become a major environmental issue. To address this issue, new food packaging materials based on renewable biomass have been studied as eco-friendly, biodegradable, and biocompatible alternatives to synthetic materials. However, although these materials are not petrochemical derivatives, the presence of contaminants cannot be excluded. This work aims to extend the knowledge on bio-based packaging materials, researching the presence of contaminants potentially able to migrate to food at concentrations of concern. In this study, we focus on two classes of contaminants, organophosphate esters (OPEs) and perfluoroalkyl substances (PFASs), carrying out migration tests toward different simulants, according to the current European regulation. PFAS analysis was performed using high-resolution liquid chromatography coupled to ion trap-tandem mass spectrometry (QTrap). OPE analyses were performed both by gas chromatography-mass spectrometry (GC-MS) and high-resolution liquid chromatography coupled to triple quadrupole mass spectrometry (TQMS). Preliminary findings demonstrate the release of toxic OPEs and PFASs from bio-based food packaging, highlighting the need to investigate the presence of potentially harmful chemicals in these materials.

Concentrations and co-occurrence of 101 emerging and legacy organic pollutants in the ultrafine, fine and coarse fractions of airborne particulates associated with treatment of waste from electrical and electronic equipment.

Occupational exposure to airborne particles can increase the development of morbidity, also because of the chemical composition of particulate matter (PM). In workplace, where manual and mechanical disassembly of electric and electronic equipment (EEE) take place, there are evident risks of respiratory exposure to a great number of different toxic organic compounds present in the electrical and plastic materials of which the equipment is made. Airborne particles are numerous, cover a wide range of sizes and are rich in toxic organic compounds. In the present work, a sampling program was conducted and ultrafine, fine and coarse airborne particles were collected in three EEE waste treatment plants. Afterwards, the extraction and analysis of polycyclic aromatic hydrocarbons (PAHs), their nitro and oxygenated derivatives (nitroPAHs, oxyPAHs), organophosphorus compounds (OPEs), Brominated Flame Retardants (BFRs), polychlorinated biphenyls (PCBs), Polybrominated Diphenyl Ethers (PBDEs), and polyfluoralkyl substances (PFASs) was performed. The percentage ratio of the mass of organic compounds and the mass of the ultrafine fraction of PM (PM0.1) was higher than those of the fine and coarse fractions. Even with low concentrations, the co-occurrence of numerous potentially toxic compounds capable of easily reaching other organs passing by the lung vasculature, through the lymph makes the working environment unhealthy.

Occurrence and migration study of chemicals from baking paper and aluminium foil.

The present work focused on the development of an analytical method suitable to study the presence and the release of organophosphate esters (OPEs) and perfluoroalkylated substances (PFASs) from food contact materials (FCMs), from baking paper and aluminium foil. Although these classes of compounds are attracting increasing attention due to their toxicity the knowledge is still insufficient. The extent of their migration from FCMs to food was estimated using different liquid simulants. Ethanol 95 % was used to simulate the contact with fatty food, whilst acetic acid 3 % to mime contact with acidic aqueous-based food and the contact mode involved the use of the ultrasound-assisted technique. Preliminary results showed the higher migration for baking paper samples in contact with aqueous simulant with contaminations in the ranges 78.30-413.21 ng/dm2 and 1.43-13.87 ng/dm2 for OPEs and PFASs respectively. These findings highlighting the need to monitor particularly OPEs in FCMs.

Characterization of organophosphate esters (OPEs) and polyfluoralkyl substances (PFASs) in settled dust in specific workplaces.

An analytical method for detecting flame retardants was slightly modified and optimized for the simultaneous determination of 11 organophosphate esters (OPEs) and 26 polyfluoralkyl substances (PFASs) contained in dust. All the analytes were determined in HPLC/MS-MS, and OPEs were also analyzed in GC/MS, and the results were compared. The study was conducted through the investigation of the Standard Reference Material SRM 2585 of the National Institute of Standard and Technology (NIST). The results were compared with the available reference mass fraction reported in the NIST certificate. The mass fraction obtained for the other OPEs and PFASs was compared to available data in the literature. After verifying the reliability of the results, the method was applied to environmental samples of settled dust, collected in four workplaces, where OPE and PFAS content is expected to be higher than in house dust: a mechanical workshop, an electronic repair center, a disassembly site, and a shredding site of two electronic waste recycling plants. By analyzing both PFASs and OPEs in the same samples, the present work demonstrated that the selected working places were more polluted in OPEs than houses; on the contrary, PFAS content in house dust proved to be more than ten times higher than that in workplaces. Additional research is necessary to confirm these data. Nevertheless, because this preliminary study showed not negligible concentrations of OPEs in some workplaces and of PFASs in houses, their monitoring should be extended to other domestic and selected working sites.

Profile of free and conjugated quercetin content in different Italian wines.

Quercetin and its structural derivatives are natural compounds belonging to the flavonoid class, widely distributed in plants. Beneficial physiological activities have been attributed to them, but some require deeper investigation. In this paper the content of quercetin and five analogues (quercetin-3-glucoside, quercetin-3-rutinoside, quercetin-3-ramnoside, quercetin-3-arabinoglucoside, 4'-O-methylquercetin) were determined by HPLC-ESI-MS/MS in wines made of different varieties of red and white vines. The aim was a comparative study focusing on quercetin and on the contribution of related compounds in twenty wines coming from different part of Italy. Wines produced from Sangiovese and Nero d'Avola, monovarietal grapes, were richest in quercetin compounds and our results were compared to our previous study and to other investigations. The proposed method resulted simple, fast, economical, and suitable for the analysis of quercetin analogues without the need of hydrolysis and falls in the optic of a 360° characterization of active wine compounds, with nutraceutical properties.

Comparison of analytical approaches for identifying airborne microorganisms in a livestock facility.

An intensive study, applied to a site characterized by multiple sources of microorganisms, was aimed at understanding the best approach to study bioaerosol. Culture-based, molecular biological, and chemical methods were applied to Particulate Matter (PM) samples collected in a livestock facility, during spring and autumn seasons, in two different outdoor areas. The first one was close to a place where feed was stored and handled and the second next to an open cowshed. Qualitative analysis of bacteria was performed by sequencing techniques applied to DNA extracted from both isolated culturable bacteria and particulate matter samples. Quantification of microorganisms was achieved through three distinct approaches. Microorganism colonies were counted, after incubation at 28 °C, and expressed as colony-forming units (CFU) per m3. Chemical method consisted in the identification of individual biomarkers, and their conversion to number of microorganisms per m3, using proper conversion factors. Finally, qPCR was applied to DNA extracted from PM samples, and the results were expressed as total amount of bacteria present in the bioaerosol (UG/m3). The presence of airborne sterols was also studied to broaden the knowledge of bioaerosol components in atmosphere. Small seasonal differences and major sampling site differences occurred. Obviously, culture-dependent method identified less and different bacteria, than culture-independent approach. The chemical approach and the culture independent metagenomic method were in good agreement. As expected, CFU/m3 accounted for not more than 0.3% of bacteria calculated as the average of chemical and culture independent metagenomic methods. The complexity of the obtained results shows that the different approaches are complementary to obtain an exhaustive description of bioaresol in terms of concentration, speciation, viability, pathogenicity.

Toxic Organic Contaminants in Airborne Particles: Levels, Potential Sources and Risk Assessment.

In the last years, many studies have focused on risk assessment of exposure of workers to airborne particulate matter (PM). Several studies indicate a strong correlation between PM and adverse health outcomes, as a function of particle size. In the last years, the study of atmospheric particulate matter has focused more on particles less than 10 µm or 2.5 µm in diameter; however, recent studies identify in particles less than 0.1 µm the main responsibility for negative cardiovascular effects. The present paper deals with the determination of 66 organic compounds belonging to six different classes of persistent organic pollutants (POPs) in the ultrafine, fine and coarse fractions of PM (PM < 0.1 µm; 0.1 < PM < 2.5 µm and 2.5 < PM < 10 µm) collected in three outdoor workplaces and in an urban outdoor area. Data obtained were analyzed with principal component analysis (PCA), in order to underline possible correlation between sites and classes of pollutants and characteristic emission sources. Emission source studies are, in fact, a valuable tool for both identifying the type of emission source and estimating the strength of each contamination source, as useful indicator of environment healthiness. Moreover, both carcinogenic and non-carcinogenic risks were determined in order to estimate human health risk associated to study sites. Risk analysis was carried out evaluating the contribution of pollutant distribution in PM size fractions for all the sites. The results highlighted significant differences between the sites and specific sources of pollutants related to work activities were identified. In all the sites and for all the size fractions of PM both carcinogenic and non-carcinogenic risk values were below acceptable and safe levels of risks recommended by the regulatory agencies.

Characterization of seven sterols in five different types of cattle feedstuffs.

This paper provides a method for the quantification of sterols in different types of calf feedstuffs based on soy, sunflower, hay, calf feed and a mixture of all of them. The free fraction and the total sterolic fraction, after saponification and acidic hydrolysis of the samples, are extracted by solvent and the sterols are identified/quantified by reversed phase HPLC coupled to tandem mass spectrometry by atmospheric pressure chemical ionization. After the recovery evaluation, the method is validated in terms of linearity (coefficient of determination R2), repeatability (coefficient of variation RSD), limit of detection and quantification. In most of the cases, the most representative phytosterol is ß-sitosterol, followed by campesterol or stigmasterol and by other minor sterols such as fucosterol, and Δ-5-avenasterol. In addition, also cholesterol and ergosterol, if present, are evaluated in all the samples. As far as we know, very little information is available on the investigated feeds, which are commonly used on farms. The results of this survey were compared to other studies, if present in literature, showing good agreement. The proposed method resulted to be simple, fast and suitable for application to other sterols, feedstuffs and derived foods. The knowledge of the sterolic content and composition is getting more and more important, both in terms of comprehension of the vegetal biochemistry and as basis for sterolomic studies.

Occurrence of Halogenated Pollutants in Domestic and Occupational Indoor Dust.

The occurrence of halogenated organic pollutants in indoor dust can be high due to the presence of textile, electronic devices, furniture, and building materials treated with these chemicals. In this explorative study, we focused on emerging organic pollutants, such as novel brominated flame retardants (nBFRs) and some perfluoroalkyl substances, together with legacy polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (BDEs) in settled dust collected in houses and workplaces such as one office and two electrotechnical and mechanical workshops. The total contribution of the investigated pollutants was lower in house and in office dusts except for few nBFRs (such as bis (2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate at a concentration of 464.5 ng/g in a house and hexachlorocyclopentadienyldibromocyclooctane at 40.4 ng/g in the office), whereas in electrotechnical and mechanical workshops a high incidence of PCBs, BDEs, and nBFRs occurred (for example, BDE 209 at a concentration of 2368.0 ng/g and tetrabromobisphenol A at 32,320.1 ng/g in electrotechnical and mechanical workshops). Estimated daily intakes were also calculated, showing that domestic and occupational environments can lead to a similar contribution in terms of human exposure. The higher exposure contribution was associated to nBFRs, whose EDIs were in the range of 3968.2-555,694.2 pg/kg bw/day. To provide a complete view about the indoor contamination, in this investigation, we also included polycyclic aromatic hydrocarbons (PAHs) and their oxygenated and nitrated derivatives. Definitely, dust collection represents a simple, fast, and cost-effective sampling and dust contamination level can be a useful indicator of environment healthiness. Besides, the presented method can be a smart tool to provide a time and money saving technique to characterize 99 pollutants thanks to a single sample treatment.

Polychlorinated Biphenyl Profile in Polyhydroxy-alkanoates Synthetized from Urban Organic Wastes.

The microbial synthesis of polyhydroxyalkanoates (PHA) from organic wastes is a valuable process to valorize available renewable resources, such as food wastes and biological sludge. Bioplastics find many applications in various sectors, from medical field to food industry. However, persistent organic pollutants could be transferred from wastes to the final product. The present paper demonstrates that the use of municipal wastes in PHA production is safe for the environment and human health and provides a polychlorinated biphenyl (PCB) profile in both commercial and waste-based PHA samples. PCB analysis in several PHA samples showed very low concentrations of the target analytes. Commercial PHA samples showed a similar PCB level with respect to PHA samples from municipal waste/sludge and higher than PHA samples from fruit waste. For all analyzed PCBs, detected concentrations were consistently lower than the ones reported in regulatory framework or guidelines.

Optimization and validation of a LC-HRMS method for aflatoxins determination in urine samples.

Mycotoxins' exposure by inhalation and/or dermal contact can occur in different branches of industry especially where heavily dusty settings are present and the handling of dusty commodities is performed. This study aims to explore the possible contribution of the occupational exposure to aflatoxins by analysing urine samples for the presence of aflatoxins B1 and M1 and aflatoxin B1-N7-guanine adduct. The study was conducted in 2017 on two groups of volunteers, the workers group, composed by personnel employed in an Italian feed plant (n = 32), and a control group (n = 29), composed by the administrative employees of the same feed plant; a total of 120 urine samples were collected and analysed. A screening method and a quantitative method with high-resolution mass spectrometry determination were developed and fully validated. Limits of detections were 0.8 and 1.5 pg/mLurine for aflatoxin B1 and M1, respectively. No quantitative determination was possible for the adduct aflatoxin B1-N7-guanine. Aflatoxin B1 and its adduct were not detected in the analysed samples, and aflatoxin M1, instead, was found in 14 samples (12%) within the range 1.9-10.5 pg/mLurine. Only one sample showed a value above the limit of quantification (10.5 pg/mLurine). The absence of a statistical difference between the mean values for workers and the control group which were compared suggests that in this specific setting, no professional exposure occurs. Furthermore, considering the very low level of aflatoxin M1 in the collected urine samples, the contribution from the diet to the overall exposure is to be considered negligible.

Real time detection of amphetamine in oral fluids by MicroNIR/Chemometrics.

In this work, a novel coupled approach MicroNIR/Chemometrics based on a miniaturized and portable spectrometer is proposed for the on site detection of amphetamines (AMP) in non pretreated oral fluids. In particular, the coupling of MicroNIR with chemometrics was investigated with the aim of developing a fast and accurate approach able to perform the on-site prediction of AMP abuse. A predictive model to be used in real cases was developed by collecting specimens from volunteers and spiked samples with increasing amounts of AMP were prepared to optimize calibration. Partial Least Square-Discriminant Analysis (PLS-DA) and Partial Least Square regression (PLS) were involved to detect and quantify AMP. Results demonstrated that MicroNIR/Chemometric platform is statistically able to identify AMP abuse in simulated oral fluid samples containing, with the accuracy and sensitivity of the actual proposed official reference methods. The method was checked against false positive and true positive response and results proved to be those required for confirmatory analyses. This method would permit to simplify AMP abuse monitoring for roadside drug testing or workplace surveillance and may be of help at first aid points.

Modeling Solid State Stability for Speciation: A Ten-Year Long Study.

Speciation studies are based on fundamental models that relate the properties of biomimetic coordination compounds to the stability of the complexes. In addition to the classic approach based on solution studies, solid state properties have been recently proposed as supporting tools to understand the bioavailability of the involved metal. A ten-year long systematic study of several different complexes of imidazole substituted ligands with transition metal ions led our group to the definition of a model based on experimental evidences. This model revealed to be a useful tool to predict the stability of such coordination complexes and is based on the induced behavior under thermal stress. Several different solid state complexes were characterized by Thermally Induced Evolved Gas Analysis by Mass Spectrometry (TI-EGA-MS). This hyphenated technique provides fundamental information to determine the solid state properties and to create a model that relates stability to coordination. In this research, the model resulting from our ten-year long systematic study of complexes of transition metal ions with imidazole substituted ligands is described. In view of a systematic addition of information, new complexes of Cu(II), Zn(II), or Cd(II) with 2-propyl-4,5-imidazoledicarboxylic acid were precipitated, characterized, and studied by means of Thermally Induced Evolved Gas Analysis performed by mass spectrometry (TI-EGA-MS). The hyphenated approach was applied to enrich the information related to thermally induced steps, to confirm the supposed decomposition mechanism, and to determine the thermal stability of the studied complexes. Results, again, allowed supporting the theory that only two main characteristic and common thermally induced decomposition behaviors join the imidazole substituted complexes studied by our group. These two behaviors could be considered as typical trends and the model allowed to predict coordination behavior and to provide speciation information.

Biomonitoring Data for Assessing Aflatoxins and Ochratoxin A Exposure by Italian Feedstuffs Workers.

Mycotoxins exposure by inhalation and/or dermal contact is possible in different branches of industry especially where heavily dusty settings are present and the handling of dusty commodities is performed. This study aims to explore the validity of the biomonitoring as a tool to investigate the intake of mycotoxins in a population of workers operating in an Italian feed plant. Serum samples were collected for the determination of aflatoxins B1 (AFB1), AFB1-Lysine adduct and ochratoxin A (OTA). A method based on liquid-liquid extraction coupled with high resolution mass spectrometry determination was developed and fully validated. For AFB1, a high number of non-detected samples (90%) was found and no statistical difference was observed comparing workers and control group. None of the analyzed samples showed the presence of AFB1-Lysine adduct. For OTA, the 100% of the analyzed samples was positive with a 33% of the samples showing a concentration higher than the limit of quantification (LOQ), but no statistical difference was highlighted between the average levels of exposed and control groups. In conclusion, the presence of AFB1 and OTA in serum cannot be attributable to occupational exposure.

A Rapid and Accurate Method for the Determination of Methylxanthines in Different Nervous System Stimulant Beverages.

Background: Caffeine, theophylline, and theobromine are methylxanthines commonly found in coffee, tea, cola, and cocoa. Other sources may be soft drinks or energy drinks. All of them are stimulants of the nervous system and can be used for the treatment of some diseases. The three xanthines produce addiction with typical abstinence symptoms. Among young people, the consumption of energy beverages is increasing, and the growing market causes concern about the caffeine intake. To evaluate intake of methylxanthines, their accurate determination can be helpful. Methods: A simple method for their determination without sample pretreatment was applied to beverages, including coffee, tea, cola, and energy drinks. The separation was achieved by LC with UV detection. The method was validated in terms of linearity, LOD and LOQ, accuracy, and reproducibility. Results: The drinks were directly injected after a filtration, and no matrix effect was demonstrated. The procedure proved to be simple, time saving, accurate, and reproducible and may be recommended for reliable assays in routine work. The investigated samples showed a range of caffeine concentration from 100 to 3050 mg/L. Possible intake of methylxanthines from miscellaneous types of drinks was assessed considering the European Food Safety Authority Opinion on the safety of caffeine consumption. Our results were in good agreement with other authors. Conclusions: A fast and accurate method for the simultaneous determination of three xanthynes in beverages was validated. The selected strategy has proved to be fit-for-purpose by applying it to different nervous system stimulant drinks. Highlights: A simple and time saving procedure was proposed for the separation, detection, and quantitation of three methylxantynes in nervous system stimulant drinks. No sample preparation was needed, and speculation could be made about the possible intake of them from beverages.

Evaluation of Bioaerosol Bacterial Components of a Wastewater Treatment Plant Through an Integrate Approach and In Vivo Assessment.

Wastewater carries different pathogenic and non-pathogenic microorganisms that can be dispersed in the surrounding environment. Workers who frequent sewage treatment plants can therefore be exposed to aerosols that contain a high concentration of potentially dangerous biological agents, or they can come into direct contact with contaminated material. This can lead to allergies, infections and occupational health-associated diseases. A characterization of biological risk assessment of bioaerosol exposure is necessary. The aim of this study was to evaluate the application of an interdisciplinary method that combines chemical and biological approaches for the analysis of a bioaerosol derived from a wastewater treatment plant (WWTP) situated in Italy. Sampled filters were analyzed by HPLC-MS/MS spectroscopy that searched for different chemical biomarkers of airborne microorganisms. The analytical quantification was compared to the biological cultural method that revealed an underrated microbial concentration. Furthermore, next generation sequencing analysis was used also to identify the uncultivable species that were not detected by the culture dependent-method. Moreover, the simple animal model Caenorhabditis elegans was used to evaluate the pathogenicity of two isolates-Acinetobacter iwoffii and Micrococcus luteus-that showed multidrug-resistance. This work represents a starting point for the development of a multidisciplinary approach for the validation of bioaerosol exposure on WWTP workplaces.

Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry Analysis of Fosetyl-Aluminum in Airborne Particulate Matter.

Fosetyl-aluminum is a synthetic fungicide administered to plants especially to prevent diseases caused by the members of the Peronosporales and several Phytophthora species. Herein, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze residues of fosetyl-A1 in air particulate matter. This study was performed in perspective of an exposure assessment of this substance of health concern in environments where high levels of fosetly-Al, relatively to airborne particulate matter, can be found after spraying it. The cleanup procedure of the analyte, from sampled filters of atmospheric particulate matter, was optimized using a Strata X solid-phase extraction cartridge, after accelerated extraction by using water. The chromatographic separation was achieved using a polymeric column based on hydrophilic interaction in step elution with water/acetonitrile, whereas the mass spectrometric detection was performed in negative electrospray ionization. The proposed method resulted to be a simple, fast, and suitable method for confirmation purposes.

Muramic and dipicolinic acids in atmospheric particulate matter as biomarkers of bacteria and bacterial spores.

Airborne bacteria are components of the atmospheric aerosol particles and can be responsible of allergic disease, regardless of their viability. In this paper, we report a method for the determination of total (viable and nonviable) bacterial content in airborne particles, using muramic and dipicolinic acids as biomarkers of bacteria and bacterial spores, respectively. The analytical procedure was optimized with bacteria and spores of Bacillus subtilis. After extraction and purification, the two biomarkers were analyzed by HPLC-ESI-MS/MS and their percentage was evaluated to be used as conversion factor. The present method for the determination of the total bacterial content was then applied to environmental samples, after a proper collection in an urban site. Thanks to the use of a low pressure impactor, capable of fractionating particles into the range of 0.03-10 µm, it was also possible to study the bacterial content in ultrafine, fine, and coarse particulate matter. The results from this study showed that muramic and dipicolinic acids can be determined together in one chromatographic run in reversed phase ion pair chromatography. Bacteria were more abundant than bacterial spores in the urban atmosphere, both showing a higher concentration in the coarse fraction of particles, although bacteria and bacterial spore amounts per unit mass of ultrafine particles were higher than in fine and coarse particles.

ER stress induced by the OCH1 mutation triggers changes in lipid homeostasis in Kluyveromyces lactis.

In Kluyveromyces lactis yeast, OCH1 encodes for the α-1,6-mannosyltrasferase that adds the initial α-1,6-mannose to the outer-chains of N-glycoproteins. Kloch1-1 mutant cells showed altered calcium homeostasis and endoplasmic reticulum (ER) stress. Since ER plays a major role in lipid biosynthesis and lipid droplet (LD) formation, herein the impact of Och1p depletion on lipid homeostasis was investigated. Transcriptional profiles of genes involved in biosynthesis of fatty acids, their amount and composition changed in mutant cells. An increased amount of ergosterol was determined in these cells. Enhanced transcription of genes involved in both synthesis and mobilization of LDs was also found in Kloch1-1 cells, accompanied by a reduced amount of LDs. We provide evidence that ER alterations, determined by protein misfolding as a result of reduced N-glycosylation, induced altered lipid homeostasis in Kloch1-1 cells. Chemical chaperone 4-phenyl butyrate (4-PBA) slightly alleviated the LD phenotype in cells depleted of Och1p. Remarkably, complete suppression of ER stress, via increased expression of plasma membrane calcium channel subunit Mid1, fully restored lipid homeostasis in mutant cells. To further reinforce this finding, low numbers of LDs were observed in wild type cells when ER stress was triggered by DTT treatment.