• Safety and Health at Work
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• v.1 no.2
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• pp.183-191
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• 2010

Objectives: The objective of this study is to investigate the distribution patterns and exposure concentrations of bioaerosols in industries suspected to have high levels of bioaerosol exposure. Methods: We selected 11 plants including 3 livestock feed plants (LF industry), 3 metal working fluids handling plants (MWFs industry), and 5 sawmills and measured total airborne bacteria, fungi, endotoxins, as well as dust. Airborne bacteria and fungi were measured with one stage impactor, six stage cascade impactor, and gelatin filters. Endotoxins were measured with polycarbonate filters. Results: The geometric means (GM) of the airborne concentrations of bacteria, fungi, and endotoxins were 1,864, $2,252\;CFU/m^3$, and $31.5\;EU/m^3$, respectively at the sawmills, followed by the LF industry (535, $585\;CFU/m^3$, and $22.0\;EU/m^3$) and MWFs industry (258, $331\;CFU/m^3$, and $8.7\;EU/m^3$). These concentrations by industry type were significantly statistically different (p < 0.01). The ratio of indoor to outdoor concentration was 6.2, 1.9, 3.2, and 3.2 for bacteria, fungi, endotoxins, and dust in the LF industry, 5.0, 0.9, 2.3, and 12.5 in the MWFs industry, and 3.7, 4.1, 3.3, and 9.7 in sawmills. The respiratory fractions of bioaerosols were differentiated by bioaerosol types and industry types: the respiratory fraction of bacteria in the LF industry, MWF industry, and sawmills was 59.4%, 72.0%, and 57.7%, respectively, and that of fungi was 77.3%, 89.5%, and 83.7% in the same order. Conclusion: We found that bioaerosol concentration was the highest in sawmills, followed by LF industry facilities and MWFs industry facilities. The indoor/outdoor ratio of microorganisms was larger than 1 and respiratory fraction of microorganisms was more than 50% of the total microorganism concentrations which might penetrate respiratory tract easily. All these findings suggest that bioaerosol in the surveyed industries should be controlled to prevent worker respiratory diseases.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.4
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• pp.393-401
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• 2013

Objectives: Endotoxins in dust generated in occupational settings is known to contribute to the occurrence of respiratory illness among workers. The relationship between the level of endotoxins in total dust or respirable particulates collected from swine farms and immunological markers related with respiratory allergy was evaluated among swine husbandry workers. Materials and Methods: Peripheral blood samples were collected from ten workers at ten swine farms at Gyeonggi province, Korea. Peripheral mononuclear cells were stimulated with phorbol 12-myristate 13-acetate and ionomycin for 48 hours. The levels of various cytokines produced at culture supernatants were determined using a commercially available ELISA kit. The concentration of particulate matter($PM_{10}$) in the indoor air of the swine farms was evaluated using a PVC membrane filter and mini volume air sampler, and endotoxin levels in the dust were measured by Limulus Amebocyte Lysate Kinetic QCL method. Results: Levels of endotoxins in the total dust were categorized into high(geometric mean: $109.35EU/m^3$) and low concentrations (geometric mean: $0.95EU/m^3$) for five swine farms. Interleukin-4 levels were higher in the high endotoxin group than in the low endotoxin group, while interferon-${\gamma}$ levels were lower in the high endotoxin group than in the low endotoxin group. The ratio (interferon-${\gamma}$ to interleukin-4), indicating immunologic skewedness against allergic reactivities, was lower in the high endotoxin group($1.15{\pm}0.60$) than the low endotoxin group($3.09{\pm}2.38$). In addition, the level of interleukin-13, another cytokine contributing to the occurrence of allergic responses, was significantly higher in the at the high endotoxin group($1.12{\pm}0.37ng/m{\ell}$) than in the low endotoxin group($0.37{\pm}0.04ng/m{\ell}$). Hematologic assessment showed significantly lower cellularity in the number of total leukocytes, neutrophils, and eosinophils in the high endotoxin group than in the low endotoxin group. Conclusions: Even though a sufficient number of swine workers and farms were not investigated, this study generlly suggests that the immunological function of swine farm workers exposed to high levels of endotoxin could be modulated toward allergic reactivities.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.103-104
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• 2002

Cyclooxygenase (COX), an important enzyme involved in mediating the inflammation, catalyzes the rate-limiting step in the formation of prostaglandins from arachidonic acid. There are two isoforms of COX, designated as COX-1 and COX-2. While COX-1 is constitutively expressed in most tissues, COX-2 can be induced transiently by proinflammatory cytokines, endotoxins, growth factors, oncogenes, UV and mitogens.(omitted)

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.3
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• pp.292-298
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• 2020

Objectives: The aim of this research is to establish Similar Exposure Groups (SEGs) for chemical and biological risk factors that occur in farm work involving 24 tasks among 15 crops. Methods: To categorize SEGs, work type, work environment, and similar tasks for each crop were considered. After confirming the chemical risk factors (pesticides, inorganic dust-total dust and PM₁₀, ammonia, and hydrogen sulfide) and biological factors (organic dust-total dust and PM₁₀, and endotoxins) that occur in the crops and tasks, similar crops and tasks were selected as SEGs. Results: Among chemical risk factors, pesticides was selected for the SEGs, which was categorized by open field, greenhouse, fruit, and specialty crops. For inorganic dust, open field (plowing harrowing, seedling, planting, harvest, and sorting and packing) and specialty crops (plowing harrowing, seedling, planting, and harvest) were selected as SEGs. For ammonia and hydrogen sulfide, livestock (preparation of farm, management of nursery bed, feeding, shipment and manure treatment) were selected as SEGs. For biological risk factors such as organic dust (total dust, PM₁₀) and endotoxins, open field (manure application), greenhouse (plowing harrowing, planting, manure application, and harvest), fruit (manure application), specialty crops (manure application, making furrows, mixing mushroom media, harvest, and sorting and packing), and livestock (preparation of farm, maintaining poultry litter, feeding, shipment and manure treatment) were selected as SEGs. Conclusions: To establish similar exposure groups in agriculture, it is important that the characteristics of each hazard factor are categorized by identifying risk factors occurring by tasks.

• Safety and Health at Work
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• v.14 no.4
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• pp.347-357
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• 2023

Introduction: The COVID-19 pandemic turned biological hazards in the working environment into a global concern. This systematized review of published reviews aimed to provide a comprehensive overview of the specific jobs and categories of workers exposed to biological hazards with the related prevention. Methods: We extracted reviews published in English and French in PubMed, Embase, and Web of Science. Two authors, working independently, subsequently screened the potentially relevant titles and abstracts recovered (step 1) and then examined relevant full texts (step 2). Disagreements were resolved by consensus. We built tables summarizing populations of exposed workers, types of hazards, types of outcomes (types of health issues, means of prevention), and routes of transmission. Results: Of 1426 studies initially identified, 79 studies by authors from every continent were selected, mostly published after 2010 (n = 63, 79.7%). About half of the reviews dealt with infectious hazards alone (n = 38, 48.1%). The industrial sectors identified involved healthcare alone (n = 16), laboratories (n = 10), agriculture (including the animal, vegetable, and grain sectors, n = 32), waste (n = 10), in addition of 11 studies without specific sectors. The results also highlighted a range of hazards (infectious and noninfectious agents, endotoxins, bioaerosols, organic dust, and emerging agents). Conclusion: This systematized overview allowed to list the populations of workers exposed to biological hazards and underlined how prevention measures in the healthcare and laboratory sectors were usually well defined and controlled, although this was not the case in the agriculture and waste sectors. Further studies are necessary to quantify these risks and implement prevention measures that can be applied in every country.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.326-330
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• 1996

To illustrate whether a hemolysin in $\delta$-endotoxins of Bacillus thuringiensis strain 73E10-2 and subsp. israelensis had immunological identity, a cyt gene of the strain 73E10-2 which encodes a hemolysin was cloned to B. subtilis (transformant 2753). The transformant 2753 containing cyt gene produced the hemolysin which lysed sheep erythrocytes after treatment of proteinase K. The hemolysin was proved also to be toxic against mosquito larvae (Aedes aegypti). The molecular weight of the hemolysin produced from the transformant 2753 was determined to be about 25 kDa by SDS-PAGE and immunoblot. The hemolysin in $\delta$-endotoxin of subsp. israelensis and subsp. kyushensis did not react on immunoblot using polyclonal anti-$\delta$-endotoxin of the strain 73E10-2, but 70-140 kDa mosquitocidal toxins in $\delta$-endotoxin of subsp. kyushuensis reacted.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.359-363
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• 1999

To prevent appearance of resistant mosquitoes against $\delta$-endotoxin of bacillus thuringiensis subsp. israelensis (Bti) in field, a mosquitocidal Bacillus thuringiensis strain 21-2(Bt21-2) producing a new type of $\delta$-endotoxin was isolated. The strain Bt 21-2 belongs to H serotype 43, B. thuringiensis subsp. guiyangiensis (Btg). The $\delta$-endotoxins from the strain Bt 21-2 and the strain Bti were a cuboid shape morphologically, but the $\delta$-endotoxin of the strain Bt 21-2 was composed of 150, 90 and 70kDa proteins on SDS-PAGE, and the antigenicity of $\delta$-endotoxin of the strain Bt 21-2 was different from that of the strain Bti on immunoblot. The $\delta$-endotoxin gene of the strain Bt 21-2 was not amplified with specific primers of $\delta$-endotoxin gene (cry4A and cry4B) of the strain Bti on PCR.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.44-46
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• 2002

This study was conducted to identify the proper analytical conditions regarding optical density for endotoxin analysis in the workplace using metalworking fludis. Our study found the "onset method" was more accurate than "time to Vmax" Reproducibility and accuracy analyzed by "onset method" was more greater than those by "time to Vmax""0.03"of optical density was the most appropriate analytical condition among onset method. Through this analytical condition, 0.998 of linearity was obtained and recovery rate ranged from 88％ to 105％ at endotoxin concentration below 5 EU/$m\ell$. No significant difference of endotoxins between "0.03"and "0.05" of optical density was observed from this study. Furthermore, correlation coefficients between them were statistically significant(p＜0.01). This study concluded that 0.03”or "0.05" of optical density is used to analyze endotoxin. Of these optical density value, value with higher linearity should be used to analyze endotoxin in environmental samples.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.1-7
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• 2000

Early studies of the molecular biology of Bacillus thuringeinsis suggested that genetic manipulation of this species could create combinations of genes more useful than those known to occur in natural isolates. Breakthroughs that made these manipulations possible include the cloning of many genes encoding endotoxins, the development of transformation vectors, and various PCR techniques. This paper reviews several genetic factors such as promoters, a 5'mRNA stabilizing sequence, 3'transcription termination sequences, and helper proteins that have been used to enhance crystal protein synthesis, and shows how these genetic elements can be manipulated with new molecular tools to develop more efficacious strains of B. thuringiensis.

• Analytical Science and Technology
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• v.15 no.5
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• pp.459-465
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• 2002

This study was performed to identify the proper analytical conditions of endotoxins regarding optical density in the workplace where metalworking fluids are used. This study found that "onset time method" was more accurate than "time to $V_{max}$ method". Reproducibility and accuracy analyzed by "onset time method" was greatly higher than the "time to $V_{max}$". The optical density of "0.03" was the most appropriate analytical condition among "onset time method". In this analytical condition, linearity of 0.998 was obtained and recovery rate ranged from 88% to 105% at the endotoxin concentrations below 5 EU/mL. No significant difference of endotoxins was observed between the optical densities of "0.03" and "0.05". However, correlation coefficients were different with statistical significance (p<0.01). This study confirmed that either the optical densities "0.03" or "0.05" should be used to analyze endotoxin. Of these optical density values, OD with correlation coefficient higher than 0.98 should be used to analyze endotoxin in environmental samples.