Correction to: Toxigenic diversity of Bacillus cereus isolated from fresh produce and effects of various factors on the growth and the cytotoxicity of B. cereus.

[This corrects the article DOI: 10.1007/s10068-023-01330-0.].

How to walk to reduce footstep noise in multi-story residential buildings.

Loud footsteps from upstairs cause disturbance to downstairs neighbours in multi-story residential buildings. In this experiment, we examined how participants walk when asked to walk quietly and evaluated the efficiency of their quiet walking patterns. Changes in vertical impact loading rates during the early stance phase, walking speed, and lower limb muscle activity when asked to walk quietly were evaluated from twenty-six young participants. Study data show that participants who struck the ground with the rearfoot reduced the impact loading rate by 44.6% with 29.3% slower walking speed than normal walking. Those who struck with the fore- or mid-foot reduced the impact loading by 69.2% with a 23.4% decrease in speed. Quiet walking with the non-rearfoot strike pattern reduced the impact loading by 48.7%, even when asked to walk as fast as normal walking. The results support the non-rearfoot strike pattern as an efficient walking strategy for lowering footstep impact.Practitioner summary: Data of this study show that voluntary gait alteration, such as adopting a non-rearfoot strike pattern, can reduce footstep impact. The study results propose that implementing such changes could be beneficial in addressing floor noise issues of multi-story residential buildings.Abbreviations: RFS: Rearfoot strike; NRFS: non-rearfoot strike; COP: Center of pressure; NW: Normal walking; QWs: Quiet walking at a preferred slower speed; QWn: Quiet walking at the speed of normal walking; EMG: Electromyography; BW: Body weight; iNEMG: integrated normalized EMG.

Toxigenic diversity of Bacillus cereus isolated from fresh produce and effects of various factors on the growth and the cytotoxicity of B. cereus.

This study analyzed the virulence, growth characteristics, and cytotoxicity of Bacillus cereus strains isolated from fresh produce, including romaine lettuce, sesame leaf, tomato, and cucumber grown by different methods. Polymerase chain reaction (PCR) was used to assess the toxigenic potential, and the cytotoxicity of B. cereus was estimated using cell-free supernatant in HEp-2 cells. The study found that hblD was the predominant diarrheal enterotoxin in the 59 isolated B. cereus strains, followed by nheB and hblC. The optimal temperatures for growth ranged from 42 to 44 °C, with the highest growth rates and shortest lag times. Cytotoxicity varied greatly depending on abiotic factors, including NaCl, pH, and medium, and was not always correlated with cell population. The study highlights the importance of establishing control measures to prevent B. cereus intoxication in fresh vegetables. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01330-0.

Prognosis of Patients with Chronic Hepatitis C Genotype 1b Infection Treated Using Daclatasvir/Asunaprevir after Sustained Virologic Response: A 6-Year Multicenter Prospective Observational Study.

Aim and Objectives: Direct-acting antiviral (DAA) therapy can cure chronic hepatitis C (CHC), and daclatasvir (DCV)/asunaprevir (ASV) was the first interferon-free DAA therapy introduced in Korea. Patients who achieve sustained virologic response (SVR) after DAA treatment are expected to have good prognoses. Therefore, in this study, we aimed to investigate the prognosis of these patients. Materials and Methods: This multicenter prospective observational study included patients with CHC who achieved SVR after DCV/ASV treatment. The primary endpoint was hepatocellular carcinoma (HCC) occurrence, which was reviewed annually. Results: We included 302 patients (median follow-up duration: 38 [16.5-60.0] months; median age: 58 [49-67] years) in the study. Cirrhosis was observed in 103 patients (34.1%), and the median Child-Pugh score was 5.0. HCC occurred in 16 patients (5.3%) within six years post-SVR; these patients were older and had higher cirrhosis prevalence, alpha-fetoprotein levels, and fibrosis-4 index scores than did those without HCC development. Cox proportional hazards analysis revealed that age > 71 years (p = 0.005) and cirrhosis (p = 0.035) were significant risk factors for HCC occurrence. Conclusions: Although the prognoses of patients who achieved SVR with DCV/ASV therapy were generally good, the risk for HCC was present, especially in older patients and in those with cirrhosis. Hence, early treatment at younger ages and regular follow-up surveillance after achieving SVR are warranted.

Development of a selective medium for the enumeration of lactic acid bacteria and bifidobacteria in food products.

This study was conducted to develop a selective medium for enumerating LAB and Bifidobacteria in food samples. Thirteen media were evaluated to determine their suitability for selectively enumerating LAB (17 bacilli and 7 cocci) and Bifidobacteria (12 strains) under aerobic and anaerobic conditions. When BL, BCP, and mMRS were supplemented with propionic acid (5 ml/l) and adjusted to pH 5, the growth of all indicator microorganisms was inhibited; however, these media also inhibited the growth of certain LAB and Bifidobacterial strains. Using propionic acid, the pH levels of BL, BCP, and mMRS were adjusted to pH 5.2, 6.0, and 6.0, respectively. These media inhibited the growth of all indicator microorganisms, whereas they did not inhibit any of the LAB and Bifidobacteria strains under anaerobic conditions. Overall, BLP (pH 5.8) lacking blood showed significantly higher bacterial counts compared with other media in food products. Further analyses indicated that BLP (pH 5.8) was the most suitable medium for enumerating LAB and Bifidobacteria in food. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01202-z.

A double layer agar plate method results in an improvement for enumerating Vibrio vulnificus and Vibrio parahaemolyticus exposed to nutrient deficiency and refrigeration temperature.

This study sought to І)investigate the effect of varying concentrations of salt on the survival of Gram-negative bacteria in artificial seawater (ASW; pH 6) stored at 4 °C, ІІ)examine the culturable populations of Vibrio vulnificus persisting in ASW with or without 1000 U/mg catalase or 0.1% sodium pyruvate (pH 6) under aerobic and oxygen-restricted environments at 4 °C, and ІІІ)determine whether double layer agar plate (DLAP) methods can improve the culturability of V. vulnificus and Vibrio parahaemolyticus in ASW (pH 6) stored at 4 °C. Once incubated in ASW containing 10% salt at 4 °C, Escherichia coli O157:H7, Salmonella Typhimurium, and Shigella flexneri survived at levels over at least 3.42-4.65 log CFU/mL on day 28, but V. vulnificus underwent the inability to produce colonies within 7 days, while maintaining its membrane integrity. A positive correlation between sodium pyruvate and maintenance of platable colony-forming capability was observed in V. vulnificus incubated aerobically. Using tryptic soy agar containing 3% salt (TSAS) overlayed by thiosulfate-citrate-bile salts-sucrose agar (TCBS), a higher platable colony count of Vibrio spp. was recovered from ASW after 25 or 30 days of storage at 4 °C, followed by TSAS, TSAS overlayed by marine agar (MA), MA, and TCBS.

Colonization of Listeria monocytogenes in potting soils as affected by bacterial community composition, storage temperature, and natural amendment.

This study aimed to characterize the bacterial community of commercial potting soils with or without Listeria monocytogenes inoculation at 5-35 °C using 16S metagenomic sequencing and evaluate the effect of natural amendments on the reduction L. monocytogenes in non-sterile potting soils. An increase in the expected operational taxonomic units of each sample with or without L. monocytogenes was proportional to the increasing storage temperatures after 5 days. Biodiversity was distinct among all potting soils for Shannon and inverse Simpson indices, with the highest diversity being observed in a soil sample stored at 35 °C for 5 days with L. monocytogenes. An increase in richness and diversity of soil bacterial community structure positively correlated with less survival of the invading L. monocytogenes. Particularly, garlic extract was demonstrated as a promising soil-amendment substrate, reducing L. monocytogenes by ≥ 4.50 log CFU/g in potting soils stored at 35 °C. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-00925-9.

Proto-oncoprotein Zbtb7c and SIRT1 repression: implications in high-fat diet-induced and age-dependent obesity.

Zbtb7c is a proto-oncoprotein that controls the cell cycle and glucose, glutamate, and lipid metabolism. Zbtb7c expression is increased in the liver and white adipose tissues of aging or high-fat diet-fed mice. Knockout or knockdown of Zbtb7c gene expression inhibits the adipocyte differentiation of 3T3-L1 cells and decreases adipose tissue mass in aging mice. We found that Zbtb7c was a potent transcriptional repressor of SIRT1 and that SIRT1 was derepressed in various tissues of Zbtb7c-KO mice. Mechanistically, Zbtb7c interacted with p53 and bound to the proximal promoter p53RE1 and p53RE2 to repress the SIRT1 gene, in which p53RE2 was particularly critical. Zbtb7c induced p53 to interact with the corepressor mSin3A-HADC1 complex at p53RE. By repressing the SIRT1 gene, Zbtb7c increased the acetylation of Pgc-1α and Pparγ, which resulted in repression or activation of Pgc-1α or Pparγ target genes involved in lipid metabolism. Our study provides a molecular target that can overexpress SIRT1 protein in the liver, pancreas, and adipose tissues, which can be beneficial in the treatment of diabetes, obesity, longevity, etc.

Development of enhanced selective media for detection of Vibrio parahaemolyticus in oysters.

This study was undertaken to develop enhanced selective media for detection of Vibrio parahaemolyticus in oysters. Primarily, tryptic soy agar (TSA) was supplemented with 4.5-5% NaCl, 0.1-0.5% oxgall, and/or 1-2% sodium citrate, and adjusted to pH 8-9. A total of 21 Vibrio spp., 24 indicators, and 26 food-borne isolates were streaked on the modified media, followed by 24 h of incubation at 37 °C. While all the indicators and isolates failed to grow on TSA containing 5% NaCl, 0.5% oxgall, and 2% sodium citrate (TSAOSS1; pH 9), V. parahaemolyticus was culturable on this selective medium. Particularly, the ability of TSAOSS1 to quantify V. parahaemolyticus in oysters was superior to thiosulphate citrate bile salts sucrose (TCBS) agar. V. parahaemolyticus distinctly produced its white-yellowish, round, and edge-pointed colony on TSAOSS1. TSAOSS1 with high selectivity potentials over TCBS may be a promising alternative for detection of V. parahaemolyticus in seafoods or natural reservoirs. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s10068-021-00877-0).

Optimization of resuscitation-promoting broths for the revival of Vibrio parahaemolyticus from a viable but nonculturable state.

This study was conducted to examine the effect of formulated resuscitation-promoting broths on the revival of viable but nonculturable Vibrio parahaemolyticus induced by cold and starvation stresses. Vibrio parahaemolyticus was incubated in artificial sea water at 4 °C for more than 8 months until this bacterium became undetectable, while retaining its intact cell count of more than 105 CFU/field over time. On day 250, V. parahaemolyticus was collected and enriched in tryptic soy broth supplemented with 3% NaCl, 10,000 U/mg catalase, 2% sodium pyruvate, 20 mM MgSO4, 5 mM EDTA, and a cell-free supernatant taken from V. parahaemolyticus ATCC 17802 in the stationary phase (pH 8). V. parahaemolyticus returned partially to a culturable state with a maximal cell density of 7.91 log CFU/mL in this formulated medium following 7 days of enrichment at 25 °C. In contrast, no V. parahaemolyticus was resuscitated when enriched in alkaline peptone water and tryptic soy broth.

Characteristics of viable-but-nonculturable Vibrio parahaemolyticus induced by nutrient-deficiency at cold temperature.

Vibrio parahaemolyticus has been consistently found to be involved in the food-borne disease outbreaks every year. Particularly, V. parahaemolyticus can be induced into a viable but nonculturable (VBNC) state under cold-starvation conditions. In this physiological state, V. parahaemolyticus losses its colony-forming ability and shows reduced metabolic activities. The subsequent failure of its detection may threaten public health-hygiene practices. Until now, evident information on physiological properties of VBNC V. parahaemolyticus and its underlying mechanism remains unclear and unorganized. Therefore, this review summarized survival behavior, persistence, and entry of pathogenic microorganisms into a VBNC state in response to various environmental conditions and discussed distinctive characteristics of VBNC cells. To survive under unfavorable environments, VBNC V. parahaemolyticus shows marked modifications in cell membrane composition, fatty acid synthesis, morphology, metabolism, gene expression, and capability of adhesion and virulence. These physiological modifications might be closely associated with an imbalance in maintaining essential biological processes within VBNC cells, thereby causing a decrease in cell membrane fluidity. To develop an efficient surveillance method and to prevent the recovery of VBNC cells in food, the induction of a VBNC state needs to be profoundly understood.

Evaluation of the microbial contamination of fresh produces and their cultivation environments from farms in Korea.

In this study, a total of 195 samples including fresh produce and farming environments was used to perform the microbial risk assessment. Levels of total aerobic bacteria ranged from 2.77 to 5.99, 6.28 to 7.81, and 1.31 to 2.74 log10 CFU/g, whereas levels of coliforms were ≤ 2.48, ≤ 3.35, and ≤ 0.85 log10 CFU/g, levels of Escherichia coli were ≤ 1.04, ≤ 0.12, and ≤ 1.69 log10 CFU/g in fresh produce, soil, and irrigation water, respectively. When the presence of pathogenic bacteria was detected, only Bacillus cereus and Staphylococcus aureus were isolated from 14 (7.2%) and 7 (3.6%) samples out of 195 samples, respectively. From the results, it was difficult to find a strong correlation between microbial contamination of fresh produce and their farming environments. However, continuous monitoring of agricultural products and related environments should be undertaken in order to ensure the microbial safety of fresh produce.

Sphingobium tyrosinilyticum sp. nov., a tyrosine hydrolyzing bacterium isolated from Korean radish garden.

A yellow-pigmented novel bacterial strain, MAH-12T, was isolated from a soil sample of Korean radish garden and was characterized using a polyphasic approach. Cells were Gram-staining negative, non-motile and rod-shaped. The strain was aerobic, catalase positive, optimum growth temperature and pH were 28-30 °C and 6.0, respectively. The novel strain is able to hydrolyze L-tyrosine, starch, esculin and 4-nitrophenyl-ß-D-galactopyranoside. On the basis of 16S rRNA gene sequence analysis, strain MAH-12T belongs to the genus Sphingobium and is most closely related to several Sphingobium type strains (97.2-97.8%). In DNA-DNA hybridization tests, the DNA relatedness between strain MAH-12T and its closest phylogenetic neighbors was below 45.0%. The DNA G + C content was 64.0 mol% and the predominant respiratory quinone was ubiquinone-10. The major cellular fatty acids were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) and C16:0. The DNA-DNA hybridization results and results of the genotypic analysis in combination with chemotaxonomic and physiological data demonstrated that strain MAH-12T represented a novel species within the genus Sphingobium, for which the name Sphingobium tyrosinilyticum is proposed. The type strain is MAH-12T (= KACC 19297T = CGMCC 1.16225T). The NCBI GenBank accession number for the 16S rRNA gene sequence of strain MAH-12T is KY964278 and the digital protologue database taxon number of strain MAH-12T is TA00463.

Review: Comparison of the effectiveness of decontaminating strategies for fresh fruits and vegetables and related limitations.

Given that it should be aware of the nutritional benefits, resulting from the consumption of fresh fruits and vegetables consumed raw and/or minimally processed, comparing the efficacy of different individual sanitizing methods against the major food-borne pathogens localized in fresh commodities is of much importance; these products are easily vulnerable to the microbial contamination. In this review, the current propensity of alternative sanitizing methods was introduced, as well as principal elements for deteriorating the cleaning effects were also discussed. Chlorine-based-sanitizers exhibited the microbial reduction of <1.12 log10 CFU/g on fruits and vegetables. Most of aqueous disinfectants showed ≤3.01 log10-redcutions against a variety of microorganisms inoculated on fresh commodities. Similarly, several physical technologies such as hydrostatic pressure and ultraviolet light were effective for reducing surviving bacterial cells could recover and grow rapidly during the whole processing, posing a potential risk of causing food-borne outbreaks associated with the fresh products. The invasion and subsequent localization of the organisms into the inner parts of products, interactions between the microbial cell and food-contacting surfaces, as well as development of biofilms could restrict the antimicrobial activity of the currently used approaches.

Effect of the precutting process on sanitizing treatments for reducing pathogens in vegetables.

The effectiveness of sanitizing treatments was investigated on reducing pathogens inoculated in whole or cut fresh vegetables, including Brussels sprouts, carrots, cherry tomatoes, paprika, and lettuce. These products were inoculated with Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes and then treated with chlorine and alcohol sanitizers, followed by the subsequent washing procedure in sterile distilled water at 25°C for 5min. Alcohol sanitizer was the most effective in inhibiting E. coli O157:H7, S. Typhimurium, and L. monocytogenes on cut Brussels sprouts, showing bacterial reductions of 4.16, 3.60, and 3.26 log CFU/g, respectively. Interestingly, the effects of sanitizing treatments were significantly lower for fresh cut produce than those for whole products (p<0.05), indicating that the effectiveness of sanitizers would be different, depending on fresh produce and the pre-cut process. Therefore, further information should be obtained to develop an effective sanitizing treatment for fresh produce.

Effects of varying concentrations of sodium chloride and acidic conditions on the behavior of Vibrio parahaemolyticus and Vibrio vulnificus cold-starved in artificial sea water microcosms.

There has been limited information available on the behavior of Vibrio parahaemolyticus and Vibrio vulnificus as a function of higher levels of NaCl in combination with acidic pH. In the present study, bacterial suspensions were transferred into artificial seawater (pH 4-7) microcosms containing 0.75% NaCl and supplemented with 5, 10, and 30% NaCl, respectively. Each of V. parahaemolyticus and V. vulnificus was inoculated in these microcosms and fermented seafood, and then stored at 4 °C until the microbial populations reached below the detectable levels on agar plates (thiosulphate-citrate-bile salts-sucrose agar and tryptic soy agar amended with 3% NaCl). Consequently, V. parahaemolyticus ATCC 27969, V. parahaemolyticus ATCC 33844, and V. vulnificus ATCC 33815 rapidly reached the viable-but-nonculturable (VBNC) state with increasing levels (≤30%) of NaCl at 4 °C. Within seven days, these pathogens in seafood appeared to enter the VBNC state at 4 °C, as shown by the fluorescence microscopic assay.

Evaluation of the microbiological quality of jacopevers and plaices in Korea, 2015-2016.

In Southeast Asian countries, including Korea, China, and Japan, the considerable amounts of raw fish have been annually consumed in the manner of live fish fillets without minimally thermal processing, increasing the risks of causing food-borne diseases. This study investigated the occurrence of total aerobic bacteria (TAB), coliform, Vibrio parahaemolyticus, Salmonella enterica serovar spp., Listeria monocytogenes, and Staphylococcus aureus in jacopevers and plaices. Total 200 live fishes were collected from randomly selected restaurants located in Anseong-si, and then they were microbiologically monitored. TAB ranged from 3.09 to 3.21 Log10 CFU/g in jacopever and plaice. Coliform in the levels of 1.54 Log10 CFU/g were detected in samples. Out of 100 jacopevers, a single jacopever (1%) exhibited the prevalence of S. aureus in the edible part, though none of pathogenic bacteria were detected. These results will be useful for understanding the microbial prevalence in the domestic living jacopevers and plaices.

CXXC5 is a transcriptional activator of Flk-1 and mediates bone morphogenic protein-induced endothelial cell differentiation and vessel formation.

CXXC5 is a member of a small subset of proteins containing CXXC-type zinc-finger domain. Here, we show that CXXC5 is a transcription factor activating Flk-1, a receptor for vascular endothelial growth factor. CXXC5 and Flk-1 were accumulated in nucli and membrane of mouse embryonic stem cells (mESCs), respectively, during their endothelial differentiation. CXXC5 overexpression induced Flk-1 transcription in both endothelium-differentiated mESCs and human umbilical vein endothelial cells (HUVECs). In vitro DNA binding assay showed direct interaction of CXXC5 on the Flk-1 promoter region, and mutation on its DNA-binding motif abolished transcriptional activity. We showed that bone morphorgenetic protein 4 (BMP4) induced CXXC5 transcription in the cells, and inhibitors of BMP signaling suppressed the CXXC5 induction and the consequent Flk-1 induction by BMP4 treatment. CXXC5 knockdown resulted in suppression of BMP4-induced stress fiber formation (56.8 ± 1.3% decrease, P<0.05) and migration (54.6 ± 1.9% decrease, P<0.05) in HUVECs. The in vivo roles of CXXC5 in BMP-signaling-specific vascular development and angiogenesis were shown by specific defect of caudal vein plex vessel formation (57.9 ± 11.8% decrease, P<0.05) in cxxc5 morpholino-injected zebrafish embryos and by suppression of BMP4-induced angiogenesis in subcutaneously injected Matrigel plugs in CXXC5(-/-) mice. Overall, CXXC5 is a transcriptional activator for Flk-1, mediating BMP signaling for differentiation and migration of endothelial cell and vessel formation.