Lenzimycins A and B, metabolites with antibacterial properties from Brevibacillus sp. associated with the dung beetle Onthophagus lenzii

Symbiotic microorganisms associated with insects can produce a wide array of metabolic products, which provide an opportunity for the discovery of useful natural products. Selective isolation of bacterial strains associated with the dung beetle, Onthophagus lenzii, identified two strains, of which the antibiotic-producing Brevibacillus sp. PTH23 inhibited the growth of Bacillus sp. CCARM 9248, which is most closely related to the well-known entomopathogen, Bacillus thuringiensis. A comprehensive chemical investigation based on antibiotic activity discovered two new antibiotics, named lenzimycins A and B (1-2), which inhibited growth of Bacillus sp. CCARM 9248. The 1H and 13C NMR, MS, MS/MS, and IR analyses elucidated the structures of 1 and 2, which comprised a novel combination of fatty acid (12-methyltetradecanoic acid), glycerol, sulfate, and N-methyl ethanolamine. Furthermore, the acid hydrolysis of 1 revealed the absolute configuration of 12-methyltetradecanoic acid as 12S by comparing its optical rotation value with authentic (R)- and (S)-12-methyltetradecanoic acid. In addition to inhibition of Bacillus sp. CCARM 9248, lenzimycins A and B were found to inhibit the growth of some human pathogenic bacteria, including Enterococcus faecium and certain strains of Enterococcus faecalis. Furthermore, the present study elucidated that lenzimycins A and B activated a reporter system designed to detect the bacterial cell envelope stress, thereby indicating an activity against the integrity of the bacterial cell wall

Quantitative Risk Evaluation by Building Type Based on Probability and Cost of Accidents

The construction industry has the highest frequency of injuries and fatal accidents compared to other industries. Therefore, an accurate evaluation of the level of risk is necessary to effectively manage accidents in the construction industry. Although risk assessments are used in the construction industry to identify and reduce risk, they are carried out qualitatively by the subjective opinion of safety managers. Therefore, this study proposed a quantitative risk assessment based on the risk levels of 17 building facilities. Moreover, this study classified the building facilities into groups of similar risk levels. This study involved five steps. The results of the study indicated that in terms of both accident probability and financial losses, the facility type with the highest risk ranking was “Residential buildings” (5.92). The risk assessment method proposed in this study can contribute toward reducing accidents by identifying the exact risk level for each facility type. Moreover, clients and contractors can utilize this study and its findings as a basis for different safety management approaches depending on the risk group level

Quantitative Analysis of the Accident Prevention Costs in Korean Construction Projects

It is essential to objectively evaluate accident prevention costs (APCs) to respond to high-accident rates in the construction industry. However, currently, no quantitative APC analysis model considers the properties of the Korean construction industry. Therefore, in this study, the APC quantification structure was derived to comprehensively evaluate the properties of Korean construction projects, such as occupational safety and health management funds, safety management expenses, and others. Subsequently, the current status of APC in Korea was analyzed based on case studies on 38 projects for which questionnaires were collected. As a result of the study, the average ratio of the APC to total construction cost of the target project was calculated to be 1.95%. In addition, an average difference exists between groups according to client types and facility types in the target project. This study developed an APC quantification model considering Korea’s safety-related laws and insurance systems. It is expected that the results of this study can be used as objective data for evaluation according to the target project type

Quantitative Analysis of the Accident Prevention Costs in Korean Construction Projects

It is essential to objectively evaluate accident prevention costs (APCs) to respond to high-accident rates in the construction industry. However, currently, no quantitative APC analysis model considers the properties of the Korean construction industry. Therefore, in this study, the APC quantification structure was derived to comprehensively evaluate the properties of Korean construction projects, such as occupational safety and health management funds, safety management expenses, and others. Subsequently, the current status of APC in Korea was analyzed based on case studies on 38 projects for which questionnaires were collected. As a result of the study, the average ratio of the APC to total construction cost of the target project was calculated to be 1.95%. In addition, an average difference exists between groups according to client types and facility types in the target project. This study developed an APC quantification model considering Korea’s safety-related laws and insurance systems. It is expected that the results of this study can be used as objective data for evaluation according to the target project type

Evaluation of Accident Risk Level Based on Construction Cost, Size and Facility Type

Compared with other industries such as manufacturing, the construction industry has a higher danger of fatalities. In Korea, the risk level in the construction industry is managed using the fatality rate per 10,000 construction workers. However, this statistic is lacking in determining the exact risk level because it does not consider the exact number of workers and fails to reflect the specific characteristics of the construction industry. In this study, the fatality rate is deduced by considering the facility type and the project size based on total cost. From the results obtained, considering the facility type, “Assembly” is seen to be the most dangerous facility type. Considering the project size based on total cost, “Less than 0.008 billion dollars” is the most dangerous construction scale. Considering both the facility type and the project size based on total cost, it was confirmed that the overall fatality rate could exceed the fatality rate respective to each facility type and project size. Using the proposed method, it is possible to determine the quantitative risk level considering specific characteristics of the construction industry

New Peptides from The Marine-Derived Fungi Aspergillus allahabadii and Aspergillus ochraceopetaliformis

Four new peptides were isolated from the culture broths of the marine-derived fungi Aspergillus allahabadii and A. ochraceopetaliformis. Based on the results of chemical and spectroscopic analyses, two compounds (1 and 2) from A. allahabadii were determined to be cyclopentapeptides, while those from A. ochraceopetaliformis were a structurally-related cyclodepsihexapeptide (3) and its linear analog (4). In addition to the presence of a D-amino acid residue, the almost reversed sequence of peptides in 3 and 4, relative to those of the 1 and 2, is notable. These new compounds exhibited moderate inhibition against the enzyme sortase A as well as a weak inhibition against isocitrate lyase (2)

Antibacterial Activity of Chromomycins from a Marine-Derived Streptomyces microflavus

A marine-derived actinomycete (Streptomyces sp. MBTI36) exhibiting antibacterial activities was investigated in the present study. The strain was identified using genetic techniques. The 16S rDNA sequence of the isolate indicated that it was most closely related to Streptomyces microflavus. Furthermore, a new chromomycin A9 (1), along with chromomycin Ap (2), chromomycin A2 (3), and chromomycin A3 (4), were isolated from the ethyl acetate extract. Their structures were determined using extensive spectroscopic methods including 1D and 2D NMR, and HRMS, as well as comparisons with previously reported data. Compounds 1–4 showed potent antibacterial activities against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA). During a passage experiment, minimum inhibitory concentration (MIC) values for compounds 1–4 showed no more than a 4-fold increase from the starting MIC value, indicating that no resistance was detected over the 21 passages

Inhibitory Effects of Nitrogenous Metabolites from a Marine-Derived <i>Streptomyces bacillaris</i> on Isocitrate Lyase of <i>Candida albicans</i>

Two nitrogenous metabolites, bacillimide (1) and bacillapyrrole (2), were isolated from the culture broth of the marine-derived actinomycete Streptomyces bacillaris. Based on the results of combined spectroscopic and chemical analyses, the structure of bacillimide (1) was determined to be a new cyclopenta[c]pyrrole-1,3-dione bearing a methylsulfide group, while the previously reported bacillapyrrole (2) was fully characterized for the first time as a pyrrole-carboxamide bearing an alkyl sulfoxide side chain. Bacillimide (1) and bacillapyrrole (2) exerted moderate (IC50 = 44.24 μM) and weak (IC50 = 190.45 μM) inhibitory effects on Candida albicans isocitrate lyase, respectively. Based on the growth phenotype using icl-deletion mutants and icl expression analyses, we determined that bacillimide (1) inhibits the transcriptional level of icl in C. albicans under C2-carbon-utilizing conditions