Factors influencing conjugated linoleic acid content of dairy products: challenges and strategies.

Conjugated linoleic acid (CLA), a bioactive fatty acid that provides various physiological benefits, has gained increasing attention in the food industry, and various studies have focused on enhancing its content in dairy products. The factors influencing CLA content in dairy products vary significantly, including lactation stage, breed type, seasonality, feed, management methods of the animals, the manufacturing processes, storage, and ripening periods of the product. Additionally, the incorporation of CLA-producing probiotic bacteria, such as Lactobacillus, Lactococcus, Bifidobacterium, and Propionibacterium, is an emerging study in this field. Studies have revealed that factors affecting the CLA content in milk affect that in dairy products as well. Furthermore, the species and strains of CLA-producing bacteria, fermentation conditions, ripening period, and type of dairy product are also contributing factors. However, production of CLA-enhanced dairy products using CLA-producing bacteria while maintaining their optimal viability and maximizing exposure to free linoleic acid remains limited. The current review emphasized the factors affecting the CLA content and related mechanisms, challenges in the application of CLA-producing probiotic bacteria, and strategies to address these challenges and enhance CLA production in dairy products. Therefore, the development of functional dairy products with enhanced CLA levels is expected to be possible.

Whey fermented by Enterococcus faecalis M157 exhibits antiinflammatory and antibiofilm activities against oral pathogenic bacteria.

The aim of the present study was to investigate the antiinflammatory and antibiofilm effects of whey fermented by Enterococcus faecalis M157 (M157-W) against oral pathogenic bacteria. The M157-W significantly inhibited IL-1ß, IL-6, and nitric oxide induced by the lipopolysaccharide of Porphyromonas gingivalis in RAW 264.7 cells. The M157-W also inhibited the production of IL-1ß and IL-8 in human periodontal ligament cells. Treatment with M157-W suppressed the phosphorylation of mitogen-activated protein kinases as well as the activation of nuclear factor-κB in RAW 264.7 cells stimulated by P. gingivalis lipopolysaccharide. Furthermore, M157-W dose-dependently inhibited Streptococcus mutans biofilm, whereas unfermented whey did not inhibit the biofilm. Treatment with M157-W significantly suppressed gtfB, gtfC, and gtfD gene expression in S. mutans compared with the control (0 µg/mL), indicating that M157-W inhibits S. mutans biofilm formation by reducing the synthesis of extracellular polymeric substances. Collectively, these results suggest that M157-W has antiinflammatory and antibiofilm activities against oral pathogenic bacteria.

Acinetobacter pullicarnis sp. nov. isolated from chicken meat.

A novel bacterial strain, named S23T, was isolated from chicken meat of local market in Korea. Cells were Gram-negative, milky-yellow colored, non-motile and coccobacillus. The strain was obligate aerobic and catalase-positive, oxidase-negative, optimum growth temperature and pH were 25 °C and pH 7.0, respectively. On the basis of 16S rRNA gene sequence analysis, strain S23T belongs to the genus Acinetobacter and is most closely related to Acinetobacter defluvii KCTC 52503 T (97.40%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) value between strain S23T and its closet phylogenetic neighbors was below 76% and 17%, respectively. The G + C content of genomic DNA of strain S23T was 41.53 mol%. The major respiratory quinone was Q-9. The major cellular fatty acids were summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c), C18:1ω9c, and C16:0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanol-amine, and phosphatidylserine. The ANI and dDDH results and results of the genotypic analysis in combination with chemotaxonomic and physiological data demonstrated that strain S23T represented a novel species within the genus Acinetobacter, for which the name Acinetobacter pullicarnis sp. nov. is proposed. The strain type is S23T (= KACC 19921 T = JCM 33150 T).

Chryseobacterium vaccae sp. nov., isolated from raw cow's milk.

Strain CA7T, a Gram-stain-negative, non-motile, non-spore-forming, aerobic and rod-shaped bacterial strain, was isolated from raw cow's milk collected from a farm affiliated with Chung-Ang University, Anseong, Korea, and characterized by a polyphasic approach. Optimal growth of strain CA7T was observed on tryptic soy agar at 30 °C and pH 7.0 with 0 % NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain CA7T belonged to the genus Chryseobacterium. The most closely related strains (16S rRNA gene sequence similarity indicated in parentheses), based on the phylogenetic analysis, were Chryseobacterium rhizosphaerae KCTC 22548T (98.08 %), Chryseobacterium nakagawai CCUG 60563T (98.61 %), Chryseobacterium jejuense KACC 12501T (97.85 %) and Chryseobacterium aurantiacum KCTC 62135T (97.78 %). Whole genome sequencing indicated that the genome size was 5 125 723 bp and had a DNA G+C content of 37.4 mol%. Average nucleotide identity values for strain CA7T with C. rhizosphaerae, C. nakagawai, C. jejuense, C. aurantiacum, and the type species of the genus Chryseobacterium, C. gleum, were 80.2, 79.8, 79.8, 79.6 and 80.4 %, respectively. The digital DNA-DNA hybridization values of CA7T compared to C. rhizosphaerae, C. nakagawai, C. jejuense, C. aurantiacum and C. gleum were 24.1, 23.9, 23.9, 23.7 and 24.3 %, respectively. The major fatty acids were iso-C15 : 0, summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl), iso-C17 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c). Menaquinone-6 was the only respiratory quinone. The major polar lipid was phosphatidylethanolamine. Based on this polyphasic taxonomic study, strain CA7T represents a novel species of the genus Chryseobacterium for which the name Chryseobacterium vaccae sp. nov. is proposed. The type strain is CA7T (=KACC 21402T=JCM 33749T).

Chryseobacterium mulctrae sp. nov., isolated from raw cow's milk.

A Gram-stain-negative bacterial strain, designated CA10T, was isolated from bovine raw milk sampled in Anseong, Republic of Korea. Cells were yellow-pigmented, aerobic, non-motile bacilli and grew optimally at 30 °C and pH 7.0 on tryptic soy agar without supplementation of NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain CA10T belonged to the genus Chryseobacterium, family Flavobacteriaceae, and was most closely related to Chryseobacterium indoltheticum ATCC 27950T (98.75 % similarity). The average nucleotide identity and digital DNA-DNA hybridization values of strain CA10T were 94.4 and 56.9 %, respectively, relative to Chryseobacterium scophthalmum DSM 16779T, being lower than the cut-off values of 95-96 and 70 %, respectively. The predominant respiratory quinone was menaquinone-6; major polar lipid, phosphatidylethanolamine; major fatty acids, iso-C15 : 0, summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl), summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) and iso-C17 : 0 3-OH. The results of physiological, chemotaxonomic and biochemical analyses suggested that strain CA10T is a novel species of genus Chryseobacterium, for which the name Chryseobacterium mulctrae sp. nov. is proposed. The type strain is CA10T (=KACC 21234T=JCM 33443T).

Chryseobacterium aureum sp. nov., isolated from the Han River, Republic of Korea.

A Gram-stain-negative, yellow-pigmented, non-motile, non-spore-forming, aerobic and rod-shaped bacterial strain, designated 17S1E7T, was isolated from the Han River, Republic of Korea, and characterized by polyphasic taxonomy analyses. Strain 17S1E7T grew optimally on tryptic soy agar at 37 °C and pH 7.0 in the absence of NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain 17S1E7T belonged to the genus Chryseobacterium and was most closely related to Chryseobacterium culicis DSM 23031T (98.54 %). The average nucleotide identity value of strain 17S1E7T was 91.1 % to Chryseobacterium culicis DSM 23031T, which was lower than the cut-off of 95-96 %. The DNA G+C content of strain 17S1E7T was 37.4 mol%. Flexirubin-type pigments were produced. The predominant respiratory quinone was menaquinone 6. The major fatty acids of strain 17S1E7T were iso-C15 : 0, summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl), iso-C17 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). The predominant polar lipid was phosphatidylethanolamine. Based on polyphasic taxonomy data, strain 17S1E7T represents a novel species of the genus Chryseobacterium, for which the name Chryseobacterium aureum sp. nov. is proposed. The type strain is 17S1E7T (=KACC 19920T=JCM 33165T).

Lactobacillus plantarum CAU1055 ameliorates inflammation in lipopolysaccharide-induced RAW264.7 cells and a dextran sulfate sodium-induced colitis animal model.

This study aimed to screen lactic acid bacteria (LAB) for their anti-inflammatory activity by using RAW264.7 cells and dextran sulfate sodium (DSS)-induced colitis. In all, 192 LAB strains were isolated from healthy human feces, of which 8 strains showed excellent nitric oxide (NO) inhibitory activity. Peptidoglycan extracts of these 8 LAB strains were subjected to NO assay, Western blot, and ELISA. Among the 8 tested strains, extracts of 4 strains significantly inhibited the production of NO, related enzyme activities such as inducible nitric oxide synthase and cyclooxygenase 2, and key cytokines such as tumor necrosis factor-α and IL-6 in RAW264.7 cells. The 4 strains belonged to Lactobacillus (CAU1054, CAU1055, CAU1064, and CAU1301). Oral administration of the 4 strains inhibited DSS-induced body weight loss, colon shortening, and colon damage in ICR mice. The colon tissue of the mice treated with Lactobacillus plantarum strain CAU1055 had significantly reduced levels of inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor-α, and IL-6. We found that strain CAU1055 could be used as a candidate probiotic strain for the prevention and treatment of inflammatory bowel disease. Further studies are warranted to confirm the mechanisms of interaction between peptidoglycan of L. plantarum strain CAU1055 and upstream cellular signaling mediators.

Identification of duck liver-expressed antimicrobial peptide 2 and characterization of its bactericidal activity.

OBJECTIVE: This study was conducted to identify duck liver-expressed antimicrobial peptide 2 (LEAP-2) and demonstrate its antimicrobial activity against various pathogens. METHODS: Tissue samples were collected from 6 to 8-week-old Pekin ducks (Anas platyrhynchos domesticus), total RNA was extracted, and cDNA was synthesized. To confirm the duck LEAP-2 transcript expression levels, quantitative real-time polymerase chain reaction was conducted. Two kinds of peptides (a linear peptide and a disulfide-type peptide) were synthesized to compare the antimicrobial activity. Then, antimicrobial activity assay and fluorescence microscopic analysis were conducted to demonstrate duck LEAP-2 bactericidal activity. RESULTS: The duck LEAP-2 peptide sequence showed high identity with those of other avian species (>85%), as well as more than 55% of identity with mammalian sequences. LEAP-2 mRNA was highly expressed in the liver with duodenum next, and then followed by lung, spleen, bursa and jejunum and was the lowest in the muscle. Both of LEAP-2 peptides efficiently killed bacteria, although the disulfide-type LEAP-2 showed more powerful bactericidal activity. Also, gram-positive bacteria was more susceptible to duck LEAP-2 than gram-negative bacteria. Using microscopy, we confirmed that LEAP-2 peptides could kill bacteria by disrupting the bacterial cell envelope. CONCLUSION: Duck LEAP-2 showed its antimicrobial activity against both gram-positive and gram-negative bacteria. Disulfide bonds were important for the powerful killing effect by disrupting the bacterial cell envelope. Therefore, duck LEAP-2 can be used for effective antibiotics alternatives.

Health risk assessment of volatile organic compounds exposure near Daegu dyeing industrial complex in South Korea.

BACKGROUND: Studying human health in areas with industrial contamination is a serious and complex issue. In recent years, attention has increasingly focused on the health implications of large industrial complexes. A variety of potential toxic chemicals have been produced during manufacturing processes and activities in industrial complexes in South Korea. A large number of dyeing industries gathered together in Daegu dyeing industrial complex. The residents near the industrial complex could be often exposed to volatile organic compounds. This study aimed to evaluate VOCs levels in the ambient air of DDIC, to assess the impact on human health risks, and to find more convincing evidences to prove these VOCs emitted from DDIC. METHODS: According to deterministic risk assessment, inhalation was the most important route. Residential indoor, outdoor and personal exposure air VOCs were measured by passive samplers in exposed area and controlled area in different seasons. Satisfaction with ambient environments and self-reported diseases were also obtained by questionnaire survey. The VOCs concentrations in exposed area and controlled area was compared by t-test. The relationships among every VOC were tested by correlation. The values of hazard quotient (HQ) and life cancer risk were estimated. RESULTS: The concentrations of measured VOCs were presented, moreover, the variety of concentrations according the distances from the residential settings to the industrial complex site in exposed area. The residential indoor, outdoor, and personal exposure concentrations of toluene, DMF and chloroform in exposed area were significantly higher than the corresponding concentrations in controlled area both in summer and autumn. Toluene, DMF, chloroform and MEK had significantly positive correlations with each other in indoor and outdoor, and even in personal exposure. The HQ for DMF exceeded 1, and the life cancer risk of chloroform was greater than 10- 4 in exposed area. The prevalence of respiratory diseases, anaphylactic diseases and cardiovascular diseases in exposed area were significantly higher than in controlled area. CONCLUSIONS: This study showed that adverse cancer and non-cancer health effects may occur by VOCs emitted from DDIC, and some risk managements are needed. Moreover, this study provides a convenient preliminarily method for pollutants source characteristics.

Environmental and Body Concentrations of Heavy Metals at Sites Near and Distant from Industrial Complexes in Ulsan, Korea.

BACKGROUND: Industrial pollution may affect the heavy metal body burden of people living near industrial complexes. We determined the average concentrations of atmospheric heavy metals in areas close to and distant from industrial complexes in Korea, and the body concentrations of these heavy metals in residents living near and distant from these facilities. METHODS: The atmospheric data of heavy metals (lead and cadmium) were from the Regional Air Monitoring Network in Ulsan. We recruited 1,148 participants, 872 who lived near an industrial complex ("exposed" group) and 276 who lived distant from industrial complexes ("non-exposed" group), and measured their concentrations of blood lead, urinary cadmium, and urinary total mercury. RESULTS: The results showed that atmospheric and human concentrations of heavy metals were higher in areas near industrial complexes. In addition, residents living near industrial complexes had higher individual and combined concentrations (cadmium + lead + mercury) of heavy metals. CONCLUSION: We conclude that residents living near industrial complexes are exposed to high concentrations of heavy metals, and should be carefully monitored.

Effects of self-carbon dioxide-generation material for active packaging on pH, water-holding capacity, meat color, lipid oxidation and microbial growth in beef during cold storage.

BACKGROUND: Active packaging refers to the mixing of additive agents into packaging materials with the purpose of maintaining or extending food product quality and shelf life. The aim of this study was to develop an easy and cheap active packaging for beef. Beef loin samples were divided into three packaging groups (C, ziplock bag packaging; T1, vacuum packaging; T2, active packaging) and stored at 4 °C for 21 days. RESULTS: The water-holding capacity was significantly (P < 0.05) higher in C and T2 than in T1 for up to 7 days of storage. The TBARS value was significantly (P < 0.05) lower in T1 and T2 after 7 days of storage. The counts of some microorganism were significantly (P < 0.05) lower in T1 and T2 after 7 days of storage; the total bacterial count and Escherichia coli count were lowest in T2 at the end of storage. CONCLUSION: These results indicate that active packaging using self-CO2 -generation materials can extend the shelf life similarly to that observed with vacuum packaging, and that the active packaging method can improve the quality characteristics of beef during cold storage. © 2017 Society of Chemical Industry.

Changes in human gut microbiota influenced by probiotic fermented milk ingestion.

We investigated the effect of consuming probiotic fermented milk (PFM) on the microbial community structure in the human intestinal tract by using high-throughput barcoded pyrosequencing. Six healthy adults ingested 2 servings of PFM daily for 3 wk, and their fecal microbiota were analyzed before and after 3 wk of PFM ingestion period and for another 3 wk following the termination of PFM ingestion (the noningestion period). Fecal microbial communities were characterized by sequencing of the V1-V3 hypervariable regions of the 16S rRNA gene. All subjects showed a similar pattern of microbiota at the phylum level, where the relative abundance of Bacteriodetes species increased during the PFM ingestion period and decreased during the noningestion period. The increase in Bacteroidetes was found to be due to an increase in members of the families Bacteroidaceae or Prevotellaceae. In contrast to PFM-induced adaptation at the phylum level, the taxonomic composition at the genus level showed a considerable alteration in fecal microbiota induced by PFM ingestion. As revealed by analysis of operational taxonomic units (OTU), the numbers of shared OTU were low among the 3 different treatments (before, during, and after PFM ingestion), but the abundance of the shared OTU was relatively high, indicating that the majority (>77.8%) of total microbiota was maintained by shared OTU during PFM ingestion and after its termination. Our results suggest that PFM consumption could alter microbial community structure in the gastrointestinal tract of adult humans while maintaining the stability of microbiota.

[The Construction of the Faculty of Hamheung Medical College in North Korea, 1946-48: An Unrest Coexistence of Political Ideology and Medical Expertise].

This paper aims to reveal how Hamheung Medical College in North Korea kept up its faculty with the trend of a new political system. The time period consists of three series of evaluations that occurred between the start of a reformation action in 1946 and the establishment of the regime in 1948. At the time, it was difficult to secure college faculty in the medical field, because of a serious shortage of medical personnel. Moreover, the problem in the recruitment of faculty at the medical college grew bigger since the members were required to have a high level of political consciousness. Then how did Hamheung Medical College accomplish this ideal securing of faculty that possessed political ideology and medical expertise? For the first time, a faculty evaluation at the local level was carried out and got rid of a few pro-Japanese or reactionary factions but maintained most of the faculty. Although academic background and research career of the faculty were considered, securing of the manpower in terms of number was crucial for the reconstruction of a professional school level. At the second time, as the central education bureau's intervention tightened the censorship, most of the faculty were evaluated as unqualified. Indeed, it was difficult to satisfy the standard of professionalism which emphasized a high level of academic career and political thought that included affiliation of Workers' Party of North Korea. The Medical College could not find faculty that could replace those professors and therefore, most of them maintained their faculty positions. Since then, the faculty who received excellent evaluations led the school at the very front. At the third time, the Medical College itself led the evaluations and implemented more relaxed standards of political ideology and medical expertise. Faculty who were cooperative to the reformation actions that North Korea carried forward or had working experience at the hospital and health service received a high level of recognition. Accordingly, the Medical College expanded itself by securing many professors, but also embodied a large gap of academic and ideological levels between them. Hence, the political ideology and medical expertise, which were set forth as the requirements for faculty, were constructed in the space of political ideal and social reality. Despite the high criteria the North Korean Government made, Hamheung Medical College's faculty fell below the average in terms of ideological and academic standards. As a way to compensate this, professors who greatly satisfied the both virtues were placed as leaders and, for supporting them, professors who taught the general education curriculum were recruited largely. And also, it appointed a large number of medical doctors who accumulated experiences in the field as new professors. Nevertheless, the Medical College struggled to raise the quality of medical education and was unable to prevent a part of its faculty from leaving to South Korea in the time of the Korean War. Thus, the political and academic virtues of the faculty at that time were not just simply about the professor individuals but were interrelated with the medical education and health care system in North Korea.

Bifidobacterium faecale sp. nov., isolated from human faeces.

A novel strain, designated strain CU3-7(T), was isolated from faeces of a two-week-old baby. The isolate was Gram-staining-positive, anaerobic and rod-shaped. Results from 16S rRNA gene sequence analysis revealed that strain CU3-7(T) was phylogenetically affiliated with members of the genus Bifidobacterium. Strain CU3-7(T) showed the highest level of sequence similarity with Bifidobacterium adolescentis KCTC 3216(T) (98.4 %), followed by Bifidobacterium ruminantium KCTC 3425(T) (97.9 %). Analysis of hsp60 sequences showed that strain CU3-7(T) was closely related to B. adolescentis KCTC 3216(T) (94.0 %) and B. ruminantium KCTC 3425(T) (92.5 %). The DNA-DNA hybridization values with the closely related strains were all below the cut-off value for species delineation, 17.0 % with B. ruminantium KCTC 3425(T) and 14.9 % with B. adolescentis KCTC 3216(T). Fructose-6-phosphate phosphoketolase activity was detected. The predominant cellular fatty acids were C16 : 0 (27.7 %), C18 : 1ω9c (27.4 %) and C18 : 1ω9c dimethylacetate (15.5 %). The DNA G+C content was 58.6 mol%. On the basis of polyphasic taxonomy, strain CU3-7(T) should be classified as the type strain of a novel species within the genus Bifidobacterium, for which the name Bifidobacterium faecale sp. nov. is proposed ( = KACC 17904(T) = JCM 19861(T)).

Polycyclic aromatic hydrocarbons exposure in residents living near a cement factory with kilns.

PURPOSE: This study was performed to investigate polycyclic aromatic hydrocarbons (PAHs) exposure in the area around a cement factory with kilns using waste, including refuse plastic fuel. METHODS: Atmospheric total suspended particulates (TSPs) for each of an exposed area and a non-exposed area were collected. Similarly, urine samples were collected from 330 subjects in the exposed area and 126 subjects in the non-exposed area. Gas chromatography with mass spectrometry was used to analyze PAHs in the collected TSP samples and the PAH metabolites, urinary 2-naphthol (2-NAP) and 1-hydroxypyrene (1-OHP), of the residents. The concentrations of urinary 2-NAP and 1-OHP were adjusted by creatinine concentrations. RESULTS: The atmospheric concentrations of PAHs, including naphthalene and pyrene, were higher in the exposed area than those in the non-exposed area. The geometric means (GMs) of the urinary 2-NAP concentrations in the exposed and non-exposed groups without work experience were 4.06 and 1.55 µg/g creatinine, respectively. The GMs of the urinary 1-OHP concentrations were 0.26 and 0.14 µg/g creatinine, respectively. The results showed that the concentrations of PAH metabolites were significantly higher in the exposed group than those in the non-exposed group (p < 0.001). Multiple linear regression analysis with the log-transformed urinary 2-NAP and 1-OHP concentrations and other variables indicated a strong correlation of residence in the exposed area and smoking with an increase in the urinary 2-NAP and 1-OHP concentrations. CONCLUSIONS: In addition to the known risk factors, this study indicated that living near a cement factory with kilns is also a risk factor for PAH exposure.

[Becoming medical doctors in colonial Korea: focusing on the faculty of medical colleges in early north Korea].

This paper traces how Koreans of north area became medical doctors in colonial Korea. Most of the past research have focused only on the well-known medical doctors, or even when they discussed a great number of doctors, many research tended to only pay attention to the explicit final results of those doctors. This research, on the other hand, includes ordinary medical doctors as well as the renowed ones, and adjusts the focus to the lifetime period of their growth and activities. As a result, the misunderstanding and obscurity about the Korean medical doctors of north area during this period have been cleared. The new characteristics of the Korean medical doctors of this period have been found, along with their embodiment of historical significance. At the time, Koreans had to get through a number of qualifications in order to become doctors. First is the unique background of origin in which the family held interest in the modern education and was capable of supporting it financially. Second is the long-term status of education that the education from elementary to high school was completed without interruption. Third is the academic qualification that among various institutions of higher education, medical science was chosen as a major. Fourth is the condition of career in which as the career as a doctor had consistently continued. Thus, in oder to become a modern medical doctor, Koreans had to properly complete these multiple steps of process. The group of Korean medical doctors in north area, which was formed after getting through these series of process, possessed a number of characteristics. Firstly, as the upper-middle classes constituted the majority of medical doctors in Korea, the societal status of doctors rose and the foundation for the career as a doctor to be persisted as the family occupation settled. Secondly, the research career and academic degree became the principal method to escape from the discrimination and hierarchy existed between doctors. A PhD degree, especially, was the significant mark for clearly displaying the abilities and outcomes of the doctors. Lastly, the research career, education experience, clinical training and such that the Korean doctors of the period had built up were weak at the time, however, they were important sources for the future medical science development. Indeed, after Liberation, the rapid settlement and growth of Korea's medical science field were largely beholden to thus. Therefore, the growth of the Koreans as doctors did not cease in colonial Korea, but instead continued onto the history of future generations. In spite of the fact that the Korean doctors's growth and activities were greatly limited under the forceful policy of colonial domination of the era, the efforts the Korean doctors had put were not in vain. Likewise, if we do not fix our attention at the dominating policy and system, but rather put together the actors' correspondence and struggles of the period, then the Korean doctors will be a part of the living history. Hereby, the clue to the paradox between the suppression of medical science in colonial Korea and its leap after Liberation can be untied.

In Vitro and In Silico Characterization of N-Formylated Two-Peptide Bacteriocin from Enterococcus faecalis CAUM157 with Anti-Listeria Activity.

Enterococcus faecalis CAUM157 (KACC 81148BP), a Gram-positive bacteria isolated from raw cow's milk, was studied for its bacteriocin production. The antimicrobial activity of CAUM157 was attributed to a two-peptide class IIb bacteriocin with potent activity against food-borne pathogen Listeria monocytogenes and periodontal disease-causing pathogens (Prevotella intermedia KCTC 15693 T and Fusobacterium nucleatum KCTC 2488 T). M157 bacteriocins exhibit high temperature and pH stability and resist hydrolytic enzyme degradation and detergent denaturation, potentially due to their structural conformation. Based on amino acid sequence, M157A and M157B were predicted to be 5.176 kDa and 5.182 kDa in size, respectively. However, purified bacteriocins and chemically synthesized N-formylated M157 peptides both showed 5.204 kDa (M157A) and 5.209 kDa (M157B) molecular mass, confirming the formylation of the N-terminal methionine of both peptides produced by strain CAUM157. Furthermore, the strain demonstrated favorable growth and fermentation with minimal bacteriocin production when cultured in whey-based media, whereas a 1.0% tryptone or soytone supplementation resulted in higher bacteriocin production. Although Ent. faecalis CAUM157 innately harbors genes for virulence factors and antimicrobial resistance (e.g., tetracycline and erythromycin), its bacteriocin production is valuable in circumventing the need for live microorganisms, particularly in food applications for pathogen control.

Complete genome sequence of bacteriocin-producing Ligilactobacillus salivarius B4311 isolated from fecal samples of broiler chicken with anti-listeria activity.

Ligilactobacillus is a genus of Gram-positive lactobacilli commonly found in the intestinal tracts of vertebrates. It has been granted a Qualified Presumption of Safety (QPS) status from the European Food Safety Authority (EFSA). One specific strain, Ligilactobacillus salivarius B4311, was isolated from fecal samples of broiler chickens from a farm associated with Chung-Ang University (Anseong, Korea). This strain was observed to have inhibitory effects against Listeria monocytogenes. In this paper, we present the complete genome sequence of Lig. salivarius B4311. The whole genome of strain B4311 comprises 2,071,255 bp assembled into 3 contigs representing a chromosome, repA-type megaplasmid, and small plasmid. The genome contains 1,963 protein-coding sequences, 22 rRNA genes, and 78 tRNA genes, with a guanine + cytosine (GC) content of 33.1%. The megaplasmid of strain B4311 was found to contain the bacteriocin gene cluster for salivaricin P, a two-peptide bacteriocin belonging to class IIb.

Efficacy and safety of galacto-oligosaccharide in the treatment of functional constipation: randomized clinical trial.

The efficacy and safety of galacto-oligosaccharides (GOS) in treating functional constipation were evaluated in a four-week randomized, double-blind clinical trial on 63 patients who met Rome IV criteria (34 GOS, 29 placebo group). The number of bowel movements per day and changes in the shape of bowel movements in the treatment group significantly improved compared to those in the control group after four weeks. The Patient Assessment Constipation Quality of Life questionnaire showed that satisfaction with constipation significantly increased in the treatment group. The levels of Bifidobacterium sp. and Lactobacillus sp. significantly increased after four weeks of GOS treatment compared to those measured at baseline. No significant adverse drug reactions were identified in any indicator except for pulse rate. Thus, the prebiotic GOS can be safely used in foods and pharmaceuticals to alleviate symptoms of functional constipation by improving the intestinal flora.

Species Profiles and Antimicrobial Resistance of Non-aureus Staphylococci Isolated from Healthy Broilers, Farm Environments, and Farm Workers.

Non-aureus staphylococci (NAS), particularly antimicrobial-resistant NAS, have a substantial impact on human and animal health. In the current study, we investigated (1) the species profiles of NAS isolates collected from healthy broilers, farm environments, and farm workers in Korea, (2) the occurrence of antimicrobial-resistant NAS isolates, especially methicillin resistance, and (3) the genetic factors involved in the methicillin and fluoroquinolone resistance. In total, 216 NAS isolates of 16 different species were collected from healthy broilers (n=178), broiler farm environments (n=18), and farm workers (n=20) of 20 different broiler farms. The two most dominant broiler-associated NAS species were Staphylococcus agnetis (23.6%) and Staphylococcus xylosus (22.9%). Six NAS isolates were mecA-positive carrying staphylococcal cassette chromosome mec (SCCmec) II (n=1), SCCmec IV (n=1), SCCmec V (n=2), or non-typeable SCCmec element (n=2). While two mecA-positive Staphylococcus epidermidis isolates from farm workers had SCCmec II and IV, a mecA-positive S. epidermidis isolate from broiler and a Staphylococcus haemolyticus isolate farm environment carried SCCmec V. The occurrence of multidrug resistance was observed in 48.1% (104/216 isolates) of NAS isolates with high resistance rates to ß-lactams (>40%) and fusidic acid (59.7%). Fluoroquinolone resistance was confirmed in 59 NAS isolates (27.3%), and diverse mutations in the quinolone resistance determining regions of gyrA, gyrB, parC, and parE were identified. These findings suggest that NAS in broiler farms may have a potential role in the acquisition, amplification, and transmission of antimicrobial resistance.