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Retinoic acid (RA) is one of the factors crucial for cell growth, differentiation, and embryogenesis; it interacts with the retinoic acid receptor and retinoic acid X receptor to eventually regulate target gene expression in chordates. RA is transformed from retinaldehyde via oxidization by retinaldehyde dehydrogenase (RALDH), which belongs to the family of oxidoreductases. Several chemicals, including disulphiram, diethylaminobenzaldehyde, and SB-210661, can effectively inhibit RALDH activity, potentially causing reproductive and developmental toxicity. The modes of action can be sequentially explained based on the molecular initiating event toward key events, and finally the adverse outcomes. Adverse outcome pathway (AOP) is a conceptual and theoretical framework that describes the sequential chain of casually liked events at different biological levels from molecular events to adverse effects. In the present review, we discussed a recently registered AOP (AOP297; inhibition of retinaldehyde dehydrogenase leads to population decline) to explain and support the weight of evidence for RALDH inhibition-related developmental toxicity using the existing knowledge.

International audience; Previously, we isolated Chlorella sp. HS2 (referred hereupon as HS2) from a local tidal rock pool and demonstrated its halotolerance and high biomass productivity under different salinity conditions. To further understand acclimation responses of this alga under high salinity stress, we performed transcriptome analysis of triplicated culture samples grown in freshwater and marine conditions at both exponential and stationary growth phases. The results indicated that the transcripts involved in photosynthesis, TCA, and Calvin cycles were downregulated, whereas the upregulation of DNA repair mechanisms and an ABCB subfamily of eukaryotic type ABC transporter was observed at high salinity condition. In addition, while key enzymes associated with glycolysis pathway and triacylglycerol (TAG) synthesis were determined to be upregulated from early growth phase, salinity stress seemed to reduce the carbohydrate content of harvested biomass from 45.6 dw% to 14.7 dw% and nearly triple the total lipid content from 26.0 dw% to 62.0 dw%. These results suggest that the reallocation of storage carbon toward lipids played a significant role in conferring the viability of this alga under high salinity stress by remediating high level of cellular stress partially resulted from ROS generated in oxygen‐evolving thylakoids as observed in a direct measure of photosystem activities.

Dinoflagellates are an important group of phytoplanktons, characterized by two dissimilar flagella and distinctive features of both plants and animals. Dinoflagellate-generated harmful algal blooms (HABs) and associated damage frequently occur in coastal areas, which are concomitant with increasing eutrophication and climate change derived from anthropogenic waste and atmospheric carbon dioxide, respectively. The severe damage and harmful effects of dinoflagellate phycotoxins in the fishing industry have been recognized over the past few decades, and the management and monitoring of HABs have attracted much attention, leaving aside the industrial application of their valuable toxins. Specific modes of action of the organisms’ toxins can effectively be utilized for producing beneficial materials, such as Botox and other therapeutic agents. This review aims to explore the potential industrial applications of marine dinoflagellate phycotoxins; furthermore, this review focuses on their modes of action and summarizes the available knowledge on them.

While the screening and development of robust algal crops have mostly focused on determining strains that exhibit the highest possible yields of biomass or desirable biomolecules, these criteria do not necessarily lead to finding algal strains with high tolerance to varying outdoor cultivation conditions. Herein, we report Chlorella sp. HS2 isolated from a tidal rock pool nearby a local coastal waterfall that presumably experienced fluctuations in salinity, pH, and temperature. Compared to two reference strains, Chlorella sp. HS2 exhibited relatively high tolerance to a wide range of salinity (0–5% (w/v) of supplemental NaCl), pH (3.0–10.5), and temperature (14–46 °C) with substantially high biomass accumulation. While the supplementation of either gaseous CO2 or sodium bicarbonate enhanced algal growth, the mixotrophic and heterotrophic cultivations of Chlorella sp. HS2 further indicated its propensity to grow favorably under the presence of organic carbon sources. Subsequent PBR cultivation of Chlorella sp. HS2 under optimal light and/or temperature conditions suggested the highest specific growth rate during mixotrophy, while the analyses of the harvested biomass identified palmitate, oleate, and linoleate as major fatty acid methyl esters, and lutein and s-carotene as predominant carotenoids. Substantially, high growth rates of Chlorella sp. HS2 under a wide range of abiotic conditions and different trophic modes with favorable biochemical composition thus strongly support our algal isolate as a robust and reliable algal crop that can be deployed to achieve high production of commercially important biomolecules and to incorporate simultaneous treatment of wastewater or CO2-replete flue gas into algal cultivation.

The concept of sustainable biodiesel production using microalgae has attracted a lot of attention as an emerging green energy technology. However, low algal biomass and lipid productivity hinder cost-effective biodiesel production. To overcome these problems, this study examined the effect of bacterial volatile compounds (VCs) on the growth and lipid production of microalga Chlorella vulgaris OW-01. The VCs of phycospheric bacteria including Hyphomonas sp., Rhizobium sp., and Sphingomonas sp. efficiently augmented algal biomass in a newly developed VCs experimental apparatus. Moreover, an apparent increase in total lipid content along with a 2.34-fold increase in productivity was observed in Hyphomonas sp. VCs–exposed algal biomass. Fatty acid methyl esters (FAME) composition also demonstrated that the algal biodiesel properties were somewhat modified by exposure to bacterial VCs. A LiOH filter-inducing CO2-removed bacterial VCs (CRBVCs) also enhanced daily growth of microalgae, as compared to the control culture (aeration), indicating that CRBVC included growth-promoting volatiles. Of those factors, volatile indole was identified as a possible algal growth enhancing factor, and it showed a higher growth-promoting effect than dimethyl disulfide and dimethyl trisulfide. Based on these results, it is speculated that the use of bacterial VCs for algal cultivation is a promising future bioprocess for the algal biomass and biodiesel production.

Abnormal melanin synthesis results in several hyperpigmentary disorders such as freckles, melanoderma, age spots, and other related conditions. In this study, we investigated the antimelanogenic effects of an extract from the microalgae Chlamydomonas reinhardtii (CE) and potential mechanisms responsible for its inhibitory effect in B16F10, normal human epidermal melanocyte cells, and human skin-equivalent models. The CE extract showed significant dose-dependent inhibitory effects on α-melanocyte-stimulating, hormone-induced melanin synthesis in cells. Additionally, the CE extract exhibited suppressive effects on the mRNA and protein expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2. The CE extract also inhibited the phosphorylation of protein kinase A and extracellular signal-related kinase, which function as upstream regulators of melanogenesis. Using a three-dimensional, reconstructed pigmented epidermis model, the CE-mediated, anti-pigmentation effects were confirmed by Fontana-Masson staining and melanin content assays. Taken together, CE extract can be used as an anti-pigmentation agent.

Lutein has attracted attention because of its beneficial roles, including alleviating cardiovascular diseases. We compared lutein production of diverse indigenous algal candidates, and selected Parachlorella sp. JD-076 as a lutein producer. The strain was cultivated under different types of photo-bioreactors (PBRs). Maximal growth was obtained from the tubular type with 2.7-fold higher dry cell weight (DCW) than in the cylindrical type. To optimize lutein production, Parachlorella sp. was exposed to various levels of illumination (100–1000 μmol m−2 s−1) and combinations of glucose and CO2 in the tubular-type PBR. High-light intensity efficiently increased DCW and lutein productivity in an intensity-dependent manner, and 5% CO2 resulted in the maximum biomass and lutein productivity compared to that of other conditions, with 2.1 g L−1 day−1 and 25 mg L−1 day−1, respectively. We speculated that the strain Parachlorella sp. JD-076 will provide a cost-effective lutein bioprocess via regulation of illumination and CO2 supply.

Microalgae have been widely considered for the production of valuable products, such as lipid-based biofuel, value-added pigments, and anti-photo aging reagents. More recently, microalgae have been considered an alternative host for recombinant protein production because of their economic benefits and ecofriendly characteristics. Additionally, many microalgal strains identified to date are generally recognized as safe (GRAS); therefore, the use of microalgae-based technology is promising. However, basic studies on the genetic engineering of microalgae are rare, despite their importance. Particularly, inducible promoter systems that can be applied for strain engineering or recombinant protein production are rarely studied; hence, a number of challenging issues remain unsolved. Therefore, in this study, we focused on the development of a convenient and compact-inducible promoter system that can be used in microalgae. Based on previous success with plant systems, we employed the alcohol-inducible AlcR-PalcA system, which originates from the filamentous fungus, Aspergillus nidulans. This system comprises only two components, a regulatory protein, AlcR, and an inducible promoter, PalcA. Therefore, construction and transformation of the gene cassettes can be easily performed. Ethanol-dependent gene expression was observed in the transformants with no significant growth retardation or inducer consumption observed in the cells cultivated under optimized conditions. Electronic supplementary material The online version of this article (10.1007/s10811-018-1480-8) contains supplementary material, which is available to authorized users.

This study suggests a new water electrolysis-based microalgae cultivation system, which is capable of both pH control and the continuous supply of carbon source for bicarbonate-based microalgae cultivation. Daily basis running of a water electrolytic cell could effectively lower the pH of an algal culture medium within 6 to 90 min depending on the applied voltage, and at the same time, approximately 100–150 mg L−1 of carbon could be successfully supplemented into the anodic algal culture solution. Interestingly, the resulting algal biomass productivity reached the same final biomass concentration of 1.67 g L−1 regardless of the applied voltage and the concentration of catholyte; moreover, the applied voltage of 3–6 V did not affect the viability or lipid productivity of algal cells. The present study conclusively demonstrated that productive and convenient bicarbonate-based cultivation of microalgae is indeed possible when coupled with the water electrolysis-based electrochemical CO2 absorption process.

Increased lipid accumulation of algal cells as a response to environmental stress factors attracted much attention of researchers to incorporate this stress response into industrial algal cultivation process with the aim of enhancing algal lipid productivity. This study applies high-salinity stress condition to a two-phase process in which microalgal cells are initially grown in freshwater medium until late exponential phase and subsequently subjected to high-salinity condition that induces excessive lipid accumulation. Our initial experiment revealed that the concentrated culture of Chlorella sorokiniana HS1 exhibited the intense fluorescence of Nile red at the NaCl concentration of 60 g/L along with 1 g/L of supplemental bicarbonate after 48 h of induction period without significantly compromising cultural integrity. These conditions were further verified with the algal culture grown for 7 days in a 1 L bottle reactor that reached late exponential phase; a 12% increment in the lipid content of harvested biomass was observed upon inducing high lipid accumulation in the concentrated algal culture at the density of 5.0 g DW/L. Although an increase in the sum of carbohydrate and lipid contents of harvested biomass indicated that the external carbon source supplemented during the induction period increased overall carbon assimilation, a decrease in carbohydrate content suggested the potential reallocation of cellular carbon that promoted lipid droplet formation under high-salinity stress. These results thus emphasize that the two-phase process can be successfully implemented to enhance algal lipid productivity by incorporating high-salinity stress conditions into the pre-concentrated sedimentation ponds of industrial algal production system.

Successful cultivation of algal biomass in outdoor open systems depends on maintaining the growth of desirable species against algal invaders that diminish biomass production potential by posing competitive pressure on target algal species. This study demonstrates a photobioreactor (PBR)-open raceway pond (ORP) hybrid system that enables the operation of PBR as a continuous source of the inoculum of desirable algal species to sustain the growth of target algal species in small-scale open raceway ponds (sORPs). A 47-day long operation of PBR-ORP hybrid system indicated that hybrid operation allowed sORPs to maintain the predominant growth of Parachlorella sp. JD076, a target microalga, whereas the sORP operated in conventional semi-continuous mode completely lost the desirable algal species. Moreover, the sORP assigned to PBR-ORP hybrid operation exhibited 40% and 62% increased algal biomass and lipid productivities compared to the sORP operated in conventional semi-continuous mode. The hybrid system produced significantly more biomass and lipids than the conventional semi-continuous system with CO2 amendment, and the hybrid system with CO2 amendment was also more productive than the same system with only aeration. These results thus align well with previous studies that suggested the operation of PBR-ORP hybrid system as a promising crop maintenance strategy to improve the growth and yield of target species at industrial algal cultivation.

This work aimed to demonstrate a new strategy for enhancing the production of carotenoids through the regulation of seesaw cross-talk between autophagy and carotenoid biosynthesis pathways in Chlamydomonas reinhardtii. Autophagy-related ATG1 and ATG8 genes were first silenced using artificial microRNA, which in turn reduced the mRNA expression of ATG1 and ATG8 by 84.4% and 74.3%, respectively. While ATG1 kinase controls early step in autophagy induction and ATG8 is an essential factor for the downstream formation of autophagosome membranes, the decreased expression of these genes led to a 2.34-fold increase in the amount of β-carotene content (i.e., 23.75 mg/g DCW). Furthermore, all mutants seemed to exhibit greater biodiesel properties than that of wild-type due to increased accumulation of saturated and monounsaturated fatty acids. These results support the role of autophagy in regulating the production of valuable metabolites, which could contribute to uplifting the economic outlook of nascent algal biorefinery.

The understanding of process parameters and limiting conditions on microalgal biomass and lipid productivities is scarce especially in chemostat cultivation. In this study, the factors limiting growth of axenic Chlorella vulgaris OW-01 in cylindrical photobioreactor under chemostat cultivation were overcome in two phases. Physiological and physicochemical analyses determined inorganic carbon, phosphorous and light intensity as major limiting factors. Their effect on system productivity was ascertained and optimized in the first phase resulting in maximum biomass and lipid productivities of 538 and 128 (mg/L/d), respectively. In the second phase, the effect of dilution rate was evaluated under optimized conditions. The biomass and lipid productivities in this phase reached to 1013 and 270 (mg/L/d), respectively at a dilution rate of 0.75d(-1), yielding >10-fold cumulative increase in productivities. The study demonstrates addressing resource limitations by constant monitoring and optimization of chemostat cultivation to achieve high biomass and lipid productivities in photobioreactors.

Interregional polity interaction in urbanized societies have long been a primary concern for researchers studying state formation and various forms of complexity. The sociopolitical development of Mahan (c. 100 BCE–300 CE) seems to have been intertwined with cooperative exchange networks among peer polities. Mahan elites used beads as means to display social status, to communicate with trading partners (or peers), and to share ideology. The symbolic beading styles display a distinct spatial distribution pattern along with other elite goods, such as mound tombs and ceremonial pottery, which reflect the formation of interaction spheres. Over time, the beads spread from the west coast to the eastern inland, and new regional exchange networks appeared throughout the Mahan area. From this, I propose that the Mahan elites maintained a cooperative networking strategy to promote social stability and legitimize local leadership status as well as reduce conflicts with neighboring polities. Ultimately, interregional polity interaction would have allowed Mahan polities to reduce potential conflicts and enable co-development with surrounding polities without integrated administrative and political systems.

Herein, a two-stage cultivation process was devised to overcome low pigment content of algal biomass grown in heterotrophy. Post-treatment conditions (i.e., light intensity, temperature, pH and salinity) were initially tested for dense heterotrophically-grown Chlorella sp. HS2 cultures in a multi-channel photobioreactor (mcPBR), and the results clearly indicated the influence of each abiotic factor on algal pigment production. Subsequently, the optimal post-treatment conditions (i.e., 455 μmol m−2 s−1, 34.8℃, pH 8.23 and 0.7% (w/v) salinity), in which highest accumulation of algal pigments is expected, were identified using Response Surface Methodology (RSM). Compared to the control cultures grown in mixotrophy for the same duration of entire two-stage process, the results indicated a significantly higher pigment productivity (i.e., 167.5 mg L–1 day−1) in a 5-L fermenter following the post-treatment at optimal conditions. Collectively, these results suggest that the post-treatment of heterotrophic cultures can be successfully deployed to harness the nascent algae-based bioeconomy.

Algal growth limitation in large-scale cultivation mostly results from high level synthesis of photosynthetic pigments, owing to self-shading effects and attenuation of light distribution. To overcome this problem, here we investigated the influence of nitrogen modulation on changes in antenna pigments as well as biomass and lipid production by Chlorella vulgaris under a chemostat continuous cultivation mode. The production of algal antenna pigments, including chlorophylls and carotenoids, was promoted in a total nitrogen (TN) concentration-dependent manner. Maximum algal biomass and lipid production were obtained from 70 mg/L of TN concentration along with a significant increase in light transmittance and reduction in antenna pigments. Furthermore, the composition of polyunsaturated fatty acids remarkably augmented at low TN concentrations. These results suggest that the reduction in algal antenna pigment synthesis via modulation of nitrogen concentration may serve as an effective strategy to enhance algal biomass and lipid production.

Skin photoaging, which is mainly induced by ultraviolet B (UVB) radiation, is prevented by the application of UV-protective agents. The microalga Nannochloropsis oceanica (N. oceanica) has been primarily reported as a potential biofuel; however, in this study, we investigated whether N. oceanica extracts exerted photoprotective effects against UVB-irradiated human dermal fibroblasts (HDFs) and which single component was responsible for the protective effect of the extracts. Two extracts-pigment and nonpigment-were prepared from N. oceanica biomass. WST-1 assay and expression analysis of interleukin genes showed that the pigment extracts were not significantly cytotoxic to HDFs. Further experiments revealed that treatment with the pigment extract upregulated the expression of collagen genes and significantly blocked UVB-induced damage such as decreased cell viability and increased ROS production. Next, to investigate the pigment composition of the extracts, HPLC analysis was conducted and violaxanthin was identified as the major pigment. The UVB photoprotective effect of the pigment extracts was confirmed in violaxanthin-treated HDFs. In addition, violaxanthin significantly attenuated UVB-induced G1 phase arrest, senescence-associated β-galactosidase activation, p16 and p21 upregulation, ERK phosphorylation and the downregulation of ECM molecules in HDFs. Therefore, we concluded that violaxanthin was a potential antiphotoaging agent.

Microbial screening and culture optimization is a laborious, multifaceted and expensive procedure often taking years and millions to identify the ideal strain for specific use. In this study, a high throughput, tablet-sized, low cost photobioreactor, herein referred as “PhotoBiobox”, was fabricated and tested for screening and culture optimization of microalgae suitable for biomass and biodiesel production, and CO2 sequestration. PhotoBiobox is equipped with a LED array and photo gradient filter offering different light intensities. PhotoBiobox was fabricated to screen and cultivate several microbial strains in 96-well plate in wide temperature range and CO2 atmosphere. To test its efficacy, a total of 12 microalgal strains were isolated from Korean freshwaters, identified and screened for high growth and lipid accumulation potential. Among the 12 strains, Parachlorella sp., JD076 showed highest growth rate, remarkable stability and tolerance to different temperature regimes. Optimization experiments using PhotoBiobox revealed that this strain had optimum temperature range and light intensity of 24–25 °C and 400 μmol m−2 s−1, respectively, with high growth rate and lipid content in 5% CO2 condition. The screening and optimization of culture conditions using PhotoBiobox took just 15 days, in total, which could radically reduce both screening costs and time. PhotoBiobox can be used as a screening and optimization reactor in several areas of microbiology and cell biology, while serving as a prototype for furthering research on miniaturization in this field.

This study demonstrates that ecologically engineered bacterial consortium could enhance microalgal biomass and lipid productivities through carbon exchange. Phycosphere bacterial diversity analysis in xenic Chlorella vulgaris (XCV) confirmed the presence of growth enhancing and inhibiting microorganisms. Co-cultivation of axenic C. vulgaris (ACV) with four different growth enhancing bacteria revealed a symbiotic relationship with each bacterium. An artificial microalgal-bacterial consortium (AMBC) constituting these four bacteria and ACV showed that the bacterial consortium exerted a statistically significant (P

Outdoor algal cultivation is frequently limited by bacterial contaminants. The aim of this study was to develop a biological control technique for removing bacterial contaminants using a small-size ciliate. During the cultivation of Chlorella sp. HS2 in a designed raceway pond, the bacterial population was significantly reduced by the ciliate strain. 18S rDNA analysis identified the ciliate as Colpoda sp. HSP-001. To verify selective bacterial grazing by the ciliate, an isolated phycospheric bacterium Microbacterium sp. was co-cultivated with Chlorella sp. HS2 while varying the ciliate cell concentrations. Colpoda sp. efficiently eliminated bacterial cells, whereas no algal grazing was observed by fluorescence microscopy. Based on the results, the utilization of Colpoda sp. HSP-001 in an outdoor algal cultivation system is a cost-effective strategy for controlling bacterial contamination without degrading the algal biomass.

Microalgal interactions with bacteria are ubiquitous, and are crucial for algal survival. Nevertheless, the detailed mechanisms underpinning the bacterial interactions and their beneficial consequences are unclear. In the current study, we studied the interactions of the model microalga Chlorella vulgaris with a model prokaryote Escherichia coli. We employed a complete set of E. coli K-12 ORF archive (ASKA) library overexpressing a complete set of E. coli K-12 open reading frames to identify the target bacterial genes whose products enhance C. vulgaris growth. During three successive screening rounds, 32 genes were selected whose overexpression resulted in >1.4-fold increase in algal chlorophyll a content. Four genes ribA, ribD, ribE and ssuE that exerted a growth-promoting effect on C. vulgaris were finally identified. These genes were involved in the bacterial riboflavin biosynthesis pathway, which was validated by determining the riboflavin content in the four selected E. coli clones and confirmed by the analysis of the growth-promoting effect of synthetic riboflavin on C. vulgaris. Collectively, these observations revealed a new bacterial determinant involved in microalgae growth promotion. The genome-wide high-throughput screening system provided insight into the long-term adaptation of C. vulgaris to bacterial interactions.

Children are particularly vulnerable to adverse health effects associated with heavy metal exposure. The goal of this study was to investigate the relationship between proximity to an industry complex and blood lead and urinary cadmium levels for children aged 7-13 who lived in Ulsan where a big petrochemical complex is located. We conducted a questionnaire survey to collect data including sociodemographics, daily habits, residential environment, etc. We also analyzed blood lead and urinary cadmium levels using Atomic Absorption Spectrometry (AAS). Data were analyzed using regression analysis. All statistical analyses were conducted with SAS software version 9.2. We calculated distance by using a Geographic Information System (ArcGIS version 10.0). The geometric mean blood lead level was 1.55 μg/dL (boys: 1.59 μg/dL, girls: 1.51 μg/dL), and the geometric mean urinary cadmium level was 0.51 μg/g creatinine (boys: 0.45 μg/g creatinine, girls: 0.58 μg/g creatinine). In the results of regression analyses, we found that urinary cadmium levels significantly decreased as distance between residence and industrial complex increased after adjusting for age, gender, income, passive smoking and the length of residence. This result was opposite to that for lead levels. Our observations support the hypothesis that urinary cadmium levels in children are related to their proximity to an industrial complex.

In this study, bicarbonate was proposed as an alternative carbon source to overcome exceedingly low CO2 fixation efficiency of conventional microalgae cultivation system. 5gL-1 of sodium bicarbonate was found to well support the growth of Dunaliella salina, showing 2.84-fold higher specific growth rate than a bicarbonate-free control. This bicarbonate-fed cultivation also could yield biomass productivity similar to that of CO2-based system as long as pH was controlled. While the supplied CO2, because of its being a gas, was mostly lost and only 3.59% of it was used for biomass synthesis, bicarbonate was effectively incorporated into the biomass with 91.40% of carbon utilization efficiency. This study showed that the bicarbonate-based microalgae cultivation is indeed possible, and can even become a truly environment-friendly and workable approach, provided that a CO2 mineralization technology is concomitantly established.

Ultraviolet (UV) light exposure causes skin photoaging, which is known to be preventable and controllable by application of UV-protective agents. In this study, we demonstrated, for the first time, that the extract of microalgae Arthrospira platensis has a reverse effect on UV-induced photodamage such as loss of cell viability, cellular senescence, DNA damage, and collagen destruction in dermal fibroblasts. Forty-eight extracts were prepared from the cell biomass by controlling culture light conditions, extract solvents, and disruption methods. Then, we analyzed their cytotoxicities using WST-1 assay and separated low and high cytotoxic extracts with normal human dermal fibroblasts (nHDFs). Using the low cytotoxic extracts, we performed UVB protection assay and selected the most effective extract demonstrating protective effect against UVB-induced nHDF damage. Flow cytometric analysis and senescence-associated (SA) β-galactosidase assay showed that pretreatment with the extract reversed UVB-induced G2/M phase cell cycle arrest and senescence in nHDFs. Furthermore, UVB-induced DNA damage in nHDFs, such as cyclobutane pyrimidine dimer formation, was significantly suppressed by the extract. Further, quantitative real-time PCR experiments revealed that the extract significantly inhibited UVB-induced upregulation of matrix metalloproteinase 1 (MMP1) and MMP3 expression in nHDFs. Therefore, we concluded that the microalgae extract can be a potential anti-photoaging agent.

Objectives: We investigated the effects of air pollution on allergic diseases (allergic rhinitis, asthma, atopic dermatitis) in metropolitan cities in Korea, adjusting for meteorological factors. Methods: Data on daily hospital visits and hospital admissions for 2003-2010 was obtained from the National Health Insurance Cooperation. Meteorological data was obtained from the Korea Meteorological Administration. We then calculated daily mean temperature, daily mean humidity, daily mean air pressure at sea level, and diurnal temperature range. We used data on air pollution provided by the National Institute of Environmental Research. Maximum daily eight-hour average ozone concentrations and the daily mean PM10 were used. We estimated excess risk and 95% confidence interval for the increasing interquatile range (IQR) of each air pollutant using Generalized Additive Models (GAM) that appropriate for time series analysis. Results: In this study, we observed an association between ozone and hospital visits for allergic rhinitis, asthma, and atopic dermatitis in all metropolitan cities, adjusting for temperature, humidity, air pressure at sea level, diurnal temperature range, and day of the week. Ozone was associated with hospital visits for allergic rhinitis, asthma, and atopic dermatitis across all metropolitan cities. However PM10 was associated with allergic-related diseases in only select cities. Also, ozone and PM10 were associated with hospital admission for asthma in all cities except Gwangju. Hospitalization for the other diseases failed to show consistent association with air pollutants. Conclusion: In the findings of this study, there was a significant association between air pollutants and allergicrelated diseases. More detailed research subdivided age group or conducting meta-analyses combining data of all cities is required.

Department of Environmental Health, College of Health Science, Korea University, Seoul, KoreaABSTRACTObjectives: The goal of this study was to investigate the relationships between proximity to an industrialcomplex and blood lead levels and urinary cadmium levels.Methods: We conducted a questionnaire survey and analyzed blood lead and urinary cadmium levels usingAtomic Absorption Spectrometry (AAs). Data was analyzed using logistic regression analysis. All statisticalanalyses were conducted with SAS software version 9.2. The distance between the residence and an industrialcomplex was calculated through a Geographical Information System (GIS). Results: A total of 967 residents living near a large petrochemical complex in Ulsan participated. The geometricmean levels of blood lead and urinary cadmium were 1.70 µg/dl (male: 1.77 µg/dl, female: 1.67 µg/dl), and 0.72µg/g creatinine (male: 0.49 µg/g cr. female: 0.89 µg/g cr.), respectively. Blood lead and urinary cadmium levelsboth increased with age and were higher among smokers compared to never smokers. Both significantly showeda decreasing trend with rising income. Results from multiple logistic regression analysis showed that urinarycadmium levels for subjects aged less than 20 years old were negatively associated with distance from theindustrial area to the residence. The results, however, indicated that the blood lead levels were positivelyassociated with the distance. Conclusions: The results of this study support that proximity to an industrial complex is related to urinarycadmium values for children. A positive finding with blood lead can be explained by the ambiguity of leadexposure sources in the general environment.Keywords: blood lead levels, urinary cadmium levels, industrial complex

The identification of novel reagents that exert a biological ultraviolet (UV)-protective effect in skin cells represents an important strategy for preventing UV-induced skin aging. To this end, we investigated the potential protective effects of Ettlia sp. YC001 extracts against UV-induced cellular damage in normal human dermal fibroblasts (NHDFs). We generated four different extracts from Ettlia sp. YC001, and found that they exhibit low cytotoxicity in NHDFs. The ethyl acetate extract of Ettlia sp. YC001 markedly decreased UVB-induced cytotoxicity. Additionally, the ethyl acetate extract significantly inhibited the production of hydrogen peroxide-induced reactive oxygen species. Moreover, it inhibited UVB-induced thymine dimers, as confirmed by luciferase assay and thymine dimer dot-blot assay. Thus, the study findings suggest Ettlia sp. YC001 extract as a novel photoprotective reagent on UVB-induced cell dysfunctions in NHDFs.

BACKGROUND There are suggestive evidence that association between particulate matter and mortality. Although there are previous studies conducted on associations between PM10 concentrations and mor...

Background Valid exposure assessment is important in analyzing the relationship between exposure and health outcomes. Land-use regression(LUR) is an emerging method to predict air pollution in smal...

Many studies have reported that the temperature effect on mortality has decreased over time. However, most of those studies did not consider lag times longer than 10 days, which is frequently used to explore its effect net out compensatory effect (harvesting) and lag effects. We sought to examine the temporal variation of the temperature effect on mortality, considering both a lag effect and mortality displacement. Time-series analysis was conducted with lag of temperature up to 21 days on all-cause, cardiovascular, cerebrovascular, and respiratory deaths. We applied a series of time-windows, 8 years long, with which we compared the oldest to more recent intervals and took consecutive annual variation, excluding an interannual harvesting effect. At the 99th percentile (29°C), relative to the 90th percentile (25°C), we found a decreasing trend of heat effect on concurrent days whereas the risk of cardiovascular deaths increased over time. Cumulative risks of deaths increased recently except for respiratory disease. At the 10th percentile (-1°C) relative to the 25th percentile (4°C), cumulative cold effects on cardiovascular and respiratory mortality have emerged recently. Our study showed differences in the temporal variation in the temperature effect on mortality at concurrent day and in cumulative term. It is suggested that the time-varying nature of the temperature-mortality relationship depends not only on suggested factors, such as improvements in technology and infrastructure, and human physiological acclimatization, but also mortality displacement and lagged effects. Further studies on its complex nature are needed to provide relevant evidence for public health policy making.