Effect of Mollusca shell extracts on inhibition of kimchi over-acidification.

Mollusca species shell such as oyster shell (OS) and snail shell (SS), are discarded after taking the meat, and the discarded shell causes the environmental problems. Therefore, recycling shell waste could potentially eliminate the environmental problems. This study aimed to evaluate the potential of OS and SS as natural calcium resources. The minerals, calcium, magnesium, potassium, phosphorus and sodium were analyzed in OS and SS extracts. Among them, the calcium content was the highest: 36.87 (%) and 33.42 (%) in the OS and SS extracts, respectively. Further, the content of ionized bioavailable form of calcium in OS and SS was higher than that of CaCO3 under simulated gastrointestinal digestion conditions. Additionally, OS and SS were added to kimchi, and their inhibitory effect on kimchi acidification was evaluated by assessing pH, titratable acidity and microbial analysis. As the results indicated that the addition of OS and SS had little effect on inhibiting the growth of lactic acid bacteria. However, it was confirmed that calcium neutralizes the organic acids produced during fermentation. Overall, the results of this study provide preliminary information on the re-use of OS and SS extracts as ionized natural calcium supplements and fermentation retardants.

Effect of headspace gas composition in kimchi packaging on the quality characteristics of kimchi.

This study evaluated the effects of gas composition in kimchi packaging on kimchi quality. Completely sealed packaging without gas inflow/outflow during fermentation (S1), packaging allowing gas outflow (S2), and packaging allowing gas inflow and outflow (S3) were used. Microbial composition analysis, volatile compound content analysis, and sensory evaluation were performed to determine the differences in kimchi quality among samples. Metabolites were examined using principal component analysis. Gas composition analysis showed that the ratio of CO2 increased during the storage period in S1, the ratio of nitrogen and CO2 contents was constant in S2, and the ratio of oxygen was significantly higher in S3. No significant differences in the lactic acid bacteria number were observed. However, coliforms were only detected in S3, and yeast and mold proliferated faster in S3 than in S2 or S1. The main compounds detected in S1 and S2 were alcohols, whereas those in S3 were esters such as ß-phenethyl acetate produced by yeast. Sensory evaluation showed that S3 had the lowest odor, taste, and overall scores, whereas S2 had the highest. In conclusion, the gas composition inside the kimchi package greatly affects the quality of kimchi. Our findings provide important data that can be useful in the manufacture of commercial kimchi. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05795-z.

Predictive growth modeling of Yersinia enterocolitica in fresh kimchi cabbage brassica pekinensis as a function of storage temperature.

We developed a predictive growth model of Yersinia enterocolitica for fresh Kimchi cabbages as a function of storage temperature (5-20 °C). The Baranyi equation used for primary modeling at these storage temperatures was suitable as a model for obtaining lag time (LT) and specific growth rate (SGR) (R2 = 0.97-0.98). As the temperature increased, the growth of Y. enterocolitica tended to increase, with SGR values of 0.33, 0.40, 0.60 and 0.68 log colony-forming units/h at 8, 11, and 15 °C, and LT values of 5.63, 3.54, 2.23 and 1.09 h, respectively. The secondary model was determined by the non-linear regression analysis. The suitability of the modeling results for the SGR and LT value was verified by determining the mean square error (<0.01), bias factor (0.919-0.999), and accuracy factor (1.032-1.136). The predicted models can be used to predict the growth of Y. enterocolitica in Kimchi cabbage at various temperatures and as an effective tool for maintaining the safe level of Y. enterocolitica in the production, processing, and distribution of fresh agricultural products.

Fabrication of Gold Nanoparticles and Cinnamaldehyde-Functionalized Paper-Based Films and Their Antimicrobial Activities against White Film-Forming Yeasts.

During storage and fermentation of kimchi, white film-forming yeasts (WFY) are generated on the surface of kimchi under various conditions. These yeasts include Candida sake, Pichia kudriavzevii, Kazachstania servazzii, Debaryomyces hansenii, and Hanseniaspora uvarum. Because of the off-odor and texture-softening properties of WFY that degrade the quality of kimchi, a method to prevent WFY is required. In this study, cinnamaldehyde (CIN) and gold nanoparticles (AuNPs) with a large surface area were grafted on a paper surface, which was termed the "Paper_AuNPs_CIN" film. CIN is an antimicrobial agent that is approved for use in food applications. In the as-fabricated Paper_AuNPs_CIN film, antimicrobial CIN molecules were physically adsorbed to the surface of AuNPs and simultaneously chemically synthesized on the paper surface via the imine reaction. The Paper_AuNPs_CIN film exhibited greater antimicrobial activity against the three WFY strains than a Paper_CIN film (which contains only CIN molecules). Since more CIN molecules were adsorbed to the large surface area of the paper-reduced AuNPs, the Paper_AuNPs_CIN film exhibited a higher antimicrobial activity. Using AuNPs and CIN simultaneously to inhibit the growth of WFY is a novel approach that has not yet been reported. The morphology and elemental mapping of the functionalized films were examined via scanning electron microscopy and energy-dispersive spectroscopy, elemental composition was analyzed via inductively coupled plasma optical emission spectroscopy, and chemical bonding and optical properties were investigated via Fourier transform infrared spectroscopy and diffuse reflectance spectroscopy. Additionally, agar-well diffusion assays were used to determine the antimicrobial activity against three representative WFY strains: C. sake, P. kudriavzevii, and K. servazzii.

Astragalin and Isoquercitrin Isolated from Aster scaber Suppress LPS-Induced Neuroinflammatory Responses in Microglia and Mice.

The current study investigated the anti-neuroinflammatory effects and mechanisms of astragalin (Ast) and isoquercitrin (Que) isolated from chamchwi (Aster scaber Thunb.) in the lipopolysaccharide (LPS)-activated microglia and hippocampus of LPS induced mice. LPS induced increased cytotoxicity, nitric oxide (NO) production, antioxidant activity, reactive oxygen species (ROS), inducible nitric oxide synthase (iNOS) expression, the release of pro-inflammatory cytokines, protein kinase B phosphorylation, and mitogen-activated protein kinases (MAPK) phosphorylation in LPS-treated microglial cells. Intraperitoneal injection of LPS also induced neuroinflammatory effects in the murine hippocampus. Ast and Que significantly reduced LPS-induced production of NO, iNOS, and pro-inflammatory cytokines in the microglia and hippocampus of mice. Therefore, anti-inflammatory effects on MAPK signaling pathways mediate microglial cell and hippocampus inflammation. In LPS-activated microglia and hippocampus of LPS-induced mice, Ast or Que inhibited MAPK kinase phosphorylation by extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 signaling proteins. Ast and Que inhibited LPS-induced ROS generation in microglia and increased 1,1-diphenyl-2-picrylhydrazyl radical scavenging. In addition, LPS treatment increased the heme oxygenase-1 level, which was further elevated after Ast or Que treatments. Ast and Que exert anti-neuroinflammatory activity by down-regulation of MAPKs signaling pathways in LPS-activated microglia and hippocampus of mice.

Immunomodulatory Activity of Extracellular Vesicles of Kimchi-Derived Lactic Acid Bacteria (Leuconostoc mesenteroides, Latilactobacillus curvatus, and Lactiplantibacillus plantarum).

Lactic acid bacteria present in Kimchi, such as Leuconostoc mesenteroides (Lm), Latilactobacillus curvatus (Lc), and Lactiplantibacillus plantarum (Lp) produce extracellular vesicles (ECVs) that modulate immune responses. The ECVs of probiotic Kimchi bacteria are abbreviated as LmV, LcV, and LpV. Treatment of macrophages (RAW264.7) with ECVs (LmV, LcV, and LpV) increased the production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin-6 (IL-6). Immunostimulatory effects exerted on the RAW264.7 cells were stronger after treatments with LmV and LcV than with LpV. Treatment of mice with LcV (1 mg/kg, orally) induced splenocyte proliferation and subsequent production of both NO and cytokines (INF-γ, TNF-α, IL-4, and IL-10). Furthermore, pre-treatment of macrophages and microglial cells with ECVs prior to LPS stimulation significantly attenuated the production of NO and pro-inflammatory cytokines (TNF-α, IL-1ß, and IL-6). Therefore, ECVs (LmV, LcV, and LpV) prevent inflammatory responses in the LPS-stimulated microglial cells by blocking the extracellular signal-regulated kinase (Erk) and p38 signaling pathways. These results showed that LmV, LcV, and LpV from Kimchi probiotic bacteria safely exert immunomodulatory effects.

Depression care services and telehealth technology use for homebound elderly in the United States.

Objectives: Despite the increasing evidence for the effectiveness of telehealth technology in screening and treating depression in older adults, they have been slowly adopted by Home Health Care (HHC) agencies. Therefore, this study was conducted to determine how HHC agencies perceive and use telehealth technology for depression care among homebound older adult patients. Methods: Five-hundred-and-sixteen staff from the National Association for Homecare & Hospice (NAHC) member home health care agencies completed the online survey. Questions were asked of HHC staff regarding performance expectancy, effort expectancy, social influences, facilitating conditions, telehealth use and intention to use/continue to use telehealth. Results: The majority had a neutral or positive perception towards telehealth. However, participants from agencies that have yet to use telehealth (mean: 3.25, SD: 1.56) reported a less intention to use the technology for depression care versus those from agencies that did (mean: 4.64, SD: 1.37). This may be partially explained by the finding that only 32% perceived themselves as having the knowledge and 25% as having resources to use telehealth. Additionally, facilitating conditions and social influences were significant predictors of intention to use/continue to use telehealth for depression care (p-values < .01). Conclusion: Overall, staff had a neutral or positive perception towards telehealth. Factors such as fewer years of experience in using telehealth and a small annual budget may explain a negative perception towards telehealth. Therefore, further education and resources are needed to support telehealth use. Future studies may consider comparing telehealth programs and identifying supporting policies.

An Interprofessional Education Simulation Workshop: Health Professions Learning Palliative Care Communication.

BACKGROUND: Patients with life-limiting illnesses need health professionals who can communicate with each other, as well as with patients and family members. Nursing faculty teach these skills in a variety of formats and, increasingly, via simulation experiences. METHOD: This pilot study aimed to compare a group of interprofessional health professions students' (N = 73) self-reported level of confidence in communication, explore behavior change and professional identity, and identify areas for future interprofessional education. Students participated in a simulated team meeting with a standardized family member of an older adult patient hospitalized with an acute aspiration pneumonia and a chronic, progressive illness. RESULTS: Postworkshop, students rated themselves as significantly more confident in interprofessional and palliative care communication (p ⩽ .001) than preworkshop, identified important areas of behavior change and professional identity, and provided faculty with ideas for future simulation workshops. CONCLUSION: Additional research is needed regarding longitudinal curricular efforts and direct patient care outcomes. [J Nurs Educ. 2018;57(8):493-497.].

Illuminating structural proteins in viral "dark matter" with metaproteomics.

Viruses are ecologically important, yet environmental virology is limited by dominance of unannotated genomic sequences representing taxonomic and functional "viral dark matter." Although recent analytical advances are rapidly improving taxonomic annotations, identifying functional dark matter remains problematic. Here, we apply paired metaproteomics and dsDNA-targeted metagenomics to identify 1,875 virion-associated proteins from the ocean. Over one-half of these proteins were newly functionally annotated and represent abundant and widespread viral metagenome-derived protein clusters (PCs). One primarily unannotated PC dominated the dataset, but structural modeling and genomic context identified this PC as a previously unidentified capsid protein from multiple uncultivated tailed virus families. Furthermore, four of the five most abundant PCs in the metaproteome represent capsid proteins containing the HK97-like protein fold previously found in many viruses that infect all three domains of life. The dominance of these proteins within our dataset, as well as their global distribution throughout the world's oceans and seas, supports prior hypotheses that this HK97-like protein fold is the most abundant biological structure on Earth. Together, these culture-independent analyses improve virion-associated protein annotations, facilitate the investigation of proteins within natural viral communities, and offer a high-throughput means of illuminating functional viral dark matter.

Methane dynamics regulated by microbial community response to permafrost thaw.

Permafrost contains about 50% of the global soil carbon. It is thought that the thawing of permafrost can lead to a loss of soil carbon in the form of methane and carbon dioxide emissions. The magnitude of the resulting positive climate feedback of such greenhouse gas emissions is still unknown and may to a large extent depend on the poorly understood role of microbial community composition in regulating the metabolic processes that drive such ecosystem-scale greenhouse gas fluxes. Here we show that changes in vegetation and increasing methane emissions with permafrost thaw are associated with a switch from hydrogenotrophic to partly acetoclastic methanogenesis, resulting in a large shift in the δ(13)C signature (10-15‰) of emitted methane. We used a natural landscape gradient of permafrost thaw in northern Sweden as a model to investigate the role of microbial communities in regulating methane cycling, and to test whether a knowledge of community dynamics could improve predictions of carbon emissions under loss of permafrost. Abundance of the methanogen Candidatus 'Methanoflorens stordalenmirensis' is a key predictor of the shifts in methane isotopes, which in turn predicts the proportions of carbon emitted as methane and as carbon dioxide, an important factor for simulating the climate feedback associated with permafrost thaw in global models. By showing that the abundance of key microbial lineages can be used to predict atmospherically relevant patterns in methane isotopes and the proportion of carbon metabolized to methane during permafrost thaw, we establish a basis for scaling changing microbial communities to ecosystem isotope dynamics. Our findings indicate that microbial ecology may be important in ecosystem-scale responses to global change.

Discovery of a novel methanogen prevalent in thawing permafrost.

Thawing permafrost promotes microbial degradation of cryo-sequestered and new carbon leading to the biogenic production of methane, creating a positive feedback to climate change. Here we determine microbial community composition along a permafrost thaw gradient in northern Sweden. Partially thawed sites were frequently dominated by a single archaeal phylotype, Candidatus 'Methanoflorens stordalenmirensis' gen. nov. sp. nov., belonging to the uncultivated lineage 'Rice Cluster II' (Candidatus 'Methanoflorentaceae' fam. nov.). Metagenomic sequencing led to the recovery of its near-complete genome, revealing the genes necessary for hydrogenotrophic methanogenesis. These genes are highly expressed and methane carbon isotope data are consistent with hydrogenotrophic production of methane in the partially thawed site. In addition to permafrost wetlands, 'Methanoflorentaceae' are widespread in high methane-flux habitats suggesting that this lineage is both prevalent and a major contributor to global methane production. In thawing permafrost, Candidatus 'M. stordalenmirensis' appears to be a key mediator of methane-based positive feedback to climate warming.

Bilateral nasoseptal flaps for endoscopic endonasal transsphenoidal approach.

A nasoseptal flap is used to reconstruct defects in the skull base when cerebrospinal fluid (CSF) leaks after the endoscopic endonasal transsphenoidal approach (EETSA). We evaluated the usefulness of elevating bilateral nasoseptal flaps with the EETSA. Sixty-seven patients (71 procedures, including 4 revisions) underwent the EETSA with bilateral nasoseptal flap elevation. We retrospectively reviewed patients' medical records, including demographic data, surgical procedures, outcomes, and complications. The entire sellar floor was exposed after elevating bilateral nasoseptal flaps. We reconstructed the defect using a right nasoseptal flap in 14 cases with intraoperative CSF leakage. The denuded sphenoidal sinus was covered with a left nasoseptal flap in 13 cases with excessive loss of sphenoidal sinus mucosa. Unused flaps (57 right flaps and 58 left flaps) were repositioned in the original sites. No postoperative CSF leak occurred. All sphenoidal sinuses covered with the left nasoseptal flap healed well without excessive crust. Two patients experienced immediate postoperative bleeding. Septal perforation occurred in 1 patient who underwent a revision operation. Bilateral nasoseptal flap elevation provided good exposure of the sellar floor with the EETSA. The nasoseptal flap could be used to reconstruct the defect after the EETSA and to cover the denuded sphenoidal sinus. The unused flaps could be repositioned in their original sites to minimize the septal defect and could be reused in revision surgery. We suggest that elevating bilateral nasoseptal flaps is a useful surgical technique in a variety of settings with the EETSA.

A case of rapidly progressing leiomyosarcoma combined with squamous cell carcinoma in the esophagus.

Esophageal leiomyosarcoma is a rare tumor that accounts for less than 1% of all malignant esophageal tumors. Esophageal leiomyosarcoma combined with squamous cell carcinoma is even rarer than solitary leiomyosarcoma. We experienced a case of leiomyosarcoma combined with squamous cell carcinoma that progressed very rapidly.

A periplasmic arsenite-binding protein involved in regulating arsenite oxidation.

Arsenic (As) is the most common toxic element in the environment, ranking first on the Superfund List of Hazardous Substances. Microbial redox transformations are the principal drivers of As chemical speciation, which in turn dictates As mobility and toxicity. Consequently, in order to manage or remediate environmental As, land managers need to understand how and why microorganisms react to As. Studies have demonstrated a two-component signal transduction system comprised of AioS (sensor kinase) and AioR (response regulator) is involved in regulating microbial AsIII oxidation, with the AsIII oxidase structural genes aioB and aioA being upregulated by AsIII. However, it is not known whether AsIII is first detected directly by AioS or by an intermediate. Herein we demonstrate the essential role of a periplasmic AsIII-binding protein encoded by aioX, which is upregulated by AsIII. An ΔaioX mutant is defective for upregulation of the aioBA genes and consequently AsIII oxidation. Purified AioX expressed without its TAT-type signal peptide behaves as a monomer (MW 32 kDa), and Western blots show AioX to be exclusively associated with the cytoplasmic membrane. AioX binds AsIII with a K(D) of 2.4 µM AsIII; however, mutating a conserved Cys108 to either alanine or serine resulted in lack of AsIII binding, lack of aioBA induction, and correlated with a negative AsIII oxidation phenotype. The discovery and characterization of AioX illustrates a novel AsIII sensing mechanism that appears to be used in a range of bacteria and also provides one of the first examples of a bacterial signal anchor protein.

Switch or funnel: how RND-type transport systems control periplasmic metal homeostasis.

Bacteria have evolved several transport mechanisms to maintain metal homeostasis and to detoxify the cell. One mechanism involves an RND (resistance-nodulation-cell division protein family)-driven tripartite protein complex to extrude a variety of toxic substrates to the extracellular milieu. These efflux systems are comprised of a central RND proton-substrate antiporter, a membrane fusion protein, and an outer membrane factor. The mechanism of substrate binding and subsequent efflux has yet to be elucidated. However, the resolution of recent protein crystal structures and genetic analyses of the components of the heavy-metal efflux family of RND proteins have allowed the developments of proposals for a substrate transport pathway. Here two models of substrate extrusion through RND protein complexes of the heavy-metal efflux protein family are described. The funnel model involves the shuttling of periplasmic substrate from the membrane fusion protein to the RND transporter and further on through the outer membrane factor to the extracellular space. Conversely, the switch model requires substrate binding to the membrane fusion protein, inducing a conformational change and creating an open-access state of the tripartite protein complex. The extrusion of periplasmic substrate bypasses the membrane fusion protein, enters the RND-transporter directly via its substrate-binding site, and is ultimately eliminated through the outer membrane channel. Evidence for and against the two models is described, and we propose that current data favor the switch model.

Differing ability to transport nonmetal substrates by two RND-type metal exporters.

The metal-exporting systems CusCFBA of Escherichia coli and GesABC of Salmonella are resistance-nodulation-division (RND)-type multiprotein systems responsible for detoxification during metal stress. In this study, the substrate range was determined for each metal transport system and possible amino acid residues important in substrate specificity were identified. The Ges system, previously identified as a gold-efflux system, conferred resistance to the greatest number and variety of organic chemicals including chloramphenicol, not recognized previously as a substrate. Phylogenetic analysis showed that GesB is most closely related to a class of RND transporters including MexF that have been shown to be responsible for exporting fluoroquinolones, chloramphenicol, and biocides. However, many of the closest homologs of GesABC appear to play a role in metal resistance judging from the genetic context. In contrast, CusCFBA belongs to a distinct family of RND-type monovalent metal-exporter systems containing a number of essential metal-binding methionines, resulting in a much narrower substrate range.

The metal efflux island of Legionella pneumophila is not required for survival in macrophages and amoebas.

Legionella pneumophila is an intracellular pathogen causing pneumonia-like disease in humans. A 43-kb putative heavy metal efflux gene island was found on the L. pneumophila genome. Large Legionella deletion strains of the metal efflux genes were tested in human THP-1-derived macrophages and amoebal Acanthamoeba castellanii cells and were able to survive and replicate similar to the wild type, suggesting that they do not play a significant role within the intracellular environment. Examination of the sequence of this genomic island revealed that some genes were not accurately annotated and there were no known metal-responsive regulators encoded in this region. Therefore, functional roles of these metal resistance genes were tested by conducting metal resistance assays. Individual genes were cloned in an expression vector and expressed in an appropriate metal-sensitive Escherichia coli background with varying concentrations of the tested metal. Of the 11 efflux systems, a role was determined only for one. A Cu(I)-translocating P(IB)-type ATPase was shown to be encoded by lpg1024. This gene, termed copA, complemented a copper-sensitive (Delta copA) E. coli strain in trans and was able to confer copper resistance.

Reverse thermal gelation of PAF-PLX-PAF block copolymer aqueous solution.

The aqueous solution of poly(L-Ala-co-L-Phe)-poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol)-poly(L-Ala-co-L-Phe) block copolymers (PAF-PLX-PAF) in a concentration range of 6.0-10.0 wt % underwent sol-to-gel transition as the temperature increased from 10 to 50 degrees C. Circular dichroism spectra, hydrophobic dye solubilization, dynamic light scattering, and transmission electron microscopy image of the polymer suggest that the polymers form micelles in water, where the hydrophilic (PLX) blocks form a shell and the hydrophobic (PAF) blocks form a core of the micelle. Circular dichroism, FTIR, and (13)C NMR spectra suggest that sol-to-gel transition accompanies partial strengthening of the beta-sheet structure of PAF and a decrease in molecular motion of the PLX. The sol-to-gel transition temperature could be controlled by varying the molecular weight of PAF and PLX blocks, the ratio of Ala to Phe, and the corresponding secondary structure of the polypeptide.