Characterization of potassium-solubilizing fungi, Mortierella spp., isolated from a poplar plantation rhizosphere soil.

Potassium-solubilizing microorganisms are capable of secreting acidic chemicals that dissolve and release potassium from soil minerals, thus facilitating potassium uptake by plants. In this study, three potassium-dissolving filamentous fungi were isolated from the rhizosphere soil of a poplar plantation in Jiangsu Province, China. Phylogenetic analyses based on ITS, 18 S, and 28 S showed that these three isolates were most similar to Mortierella. These strains also possessed spherical or ellipsoidal spores, produced sporangia at the hyphal tip, and formed petal-like colonies on PDA media resembling those of Mortierella species. These findings, along with further phenotypic observations, suggest that these isolates were Mortierella species. In addition, the potassium-dissolution experiment showed that strain 2K4 had a relatively high potassium-solubilizing capacity among these isolated fungi. By investigating the influences of different nutrient conditions (carbon source, nitrogen source, and inorganic salt) and initial pH values on the potassium-dissolving ability, the optimal potassium-solubilization conditions of the isolate were determined. When potassium feldspar powder was used as an insoluble potassium source, isolate 2K4 exhibited a significantly better polysaccharide aggregation ability on the formed mycelium-potassium feldspar complex. The composition and content of organic acids secreted by strain 2K4 were further detected, and the potassium-dissolution mechanism of the Mortierella species and its growth promotion effect were discussed, using maize as an example.

Discovery and bioinspired total syntheses of unprecedented sesquiterpenoid dimers unveiled bifurcating [4 + 2] cycloaddition and target differentiation of enantiomers.

[4 + 2] cycloaddition has led to diverse polycyclic chiral architectures, serving as novel sources for organic synthesis and biological exploration. Here, an unprecedented class of cadinane sesquiterpene [4 + 2] dimers, henryinins A-E (1-5), with a unique 6/6/6/6/6-fused pentacyclic system, were isolated from Schisandra henryi. The divergent total syntheses of compounds 1-5 and their enantiomers (6-10) were concisely accomplished in eight linear steps using a protection-free approach. Mechanistic studies illustrated the origin of selectivity in the key [4 + 2] cycloaddition as well as the inhibition of reaction pathway bifurcation via desymmetrization. The chemical proteomics results showed that a pair of enantiomers shared common targets (PRDX5 C100 and BLMH C73) and had unique targets (USP45 C588 for 4 and COG7 C419 for 9). This work provides experimental evidence for the discovery of unprecedented cadinane dimers from selective Diels-Alder reaction and a powerful strategy to explore the biological properties of natural products.

Reductive Catalytic Difluorocarbene Transfer via Palladium Catalysis.

A palladium-catalyzed reductive difluorocarbene transfer reaction that tames difluorocarbene to couple with two electrophiles has been developed, representing a new mode of difluorocarbene transfer reaction. The approach uses low-cost and bulk industrial chemical chlorodifluoromethane (ClCF2 H) as the difluorocarbene precursor. It produces a variety of difluoromethylated (hetero)arenes from widely available aryl halides/triflates and proton sources, featuring high functional group tolerance and synthetic convenience without preparing organometallic reagents. Experimental mechanistic studies reveal that an unexpected Pd0/II catalytic cycle is involved in this reductive reaction, wherein the oxidative addition of palladium(0) difluorocarbene ([Pd0 (Ln )]=CF2 ) with aryl electrophile to generate the key intermediate aryldifluoromethylpalladium [ArCF2 Pd(Ln )X], followed by reaction with hydroquinone, is responsible for the reductive difluorocarbene transfer.

Heat-Killed Bifidobacterium longum BBMN68 in Pasteurized Yogurt Alleviates Mugwort Pollen-Induced Allergic Airway Responses through Gut Microbiota Modulation in a Murine Model.

Many probiotic bacteria have been proven to prevent allergic airway responses through immunomodulation. This study was conducted to evaluate the effects of heat-killed Bifidobacterium longum BBMN68 (BBMN68) in pasteurized yogurt on the alleviation of mugwort pollen (MP)-induced allergic inflammation. BALB/c mice aged 5-6 weeks were randomly assigned and fed pasteurized yogurt containing heat-killed BBMN68 for 27 days, followed by allergic sensitization and challenge with MP extract. The allergic mice that received pasteurized yogurt containing heat-killed BBMN68 had improved immune status, including a lower serum IgE level, decreased serum interleukin (IL)-4, IL-5, and IL-13 concentrations, and alleviated airway inflammation manifested by increased macrophage and decreased eosinophil and neutrophil counts in BALF, as well as airway remodeling and suppressed peribronchial cellular infiltration. Moreover, oral administration of pasteurized yogurt containing heat-killed BBMN68 significantly modulated gut microbiota composition by influencing the proportion of beneficial genera associated with inflammation and immunity, such as Lactobacillus, Candidatus_Saccharimonas, Odoribacter, and Parabacteroides, which also negatively correlated with serum IgE and Th2 cytokine levels. These results demonstrated that pasteurized yogurt containing heat-killed BBMN68 had mitigative effects on allergic airway inflammation, likely through maintaining the systemic Th1/Th2 immune balance by altering the structure and function of the gut microbiota.

Influence of Temperature during Freeze-Drying Process on the Viability of Bifidobacterium longum BB68S.

Maintaining optimum temperature during freeze-drying is crucial to ensuring the viability of strains. In this study, we evaluated the effect of pre-freezing, sublimation and desorption temperatures on the viability of Bifidobacterium longum BB68S (BB68S). Moreover, we examined the water content, water activity, enzyme activities, and scanning electron microscope of BB68S to explore mechanisms underpinning the effect of temperature on viability. Our analyses revealed the highest survival rates of BB68S collected after pre-freezing and sublimation drying at -40 °C (94.9 ± 2.2%) and -10 °C (65.4 ± 3.8%), respectively. Additionally, response surface methodology demonstrated that the optimum conditions for freeze-drying of BB68S were pre-freezing temperature at -45.52 °C and sublimation temperature at -6.58 °C, and the verification test showed that survival rates of BB68S could reach 69.2 ± 3.8%. Most of the vitality loss occurred during the sublimation drying phase. Further studies showed that different sublimation temperatures affected water content and activity, ß-galactosidase, lactate dehydrogenase, Na+-K+-ATP and Ca2+-Mg2+-ATP activities. In conclusion, the temperature during freeze-drying, especially sublimation temperature, is a key factor affecting the survival rate of BB68S, and the vitality loss during freeze-drying process might be due to compromised cell membrane integrity and permeability.

Phosphorus-Solubilizing Capacity of Mortierella Species Isolated from Rhizosphere Soil of a Poplar Plantation.

Phosphorus is one of the main nutrients necessary for plant growth and development. Phosphorus-dissolving microorganisms may convert insoluble phosphorus in soil into available phosphorus that plants can easily absorb and utilize. In this study, four phosphorus-solubilizing fungi (L3, L4, L5, and L12) were isolated from the rhizosphere soil of a poplar plantation in Dongtai, Jiangsu Province, China. Phylogenetic analysis based on the internal transcribed spacer (ITS) and large subunit (LSU) of the ribosomal DNA sequences showed that the ITS and 28S sequences of isolates were the most similar to those of Mortierella. Morphological observation showed that most colonies grew in concentric circles and produced spores under different culture conditions. These results and further microscopic observations showed that these isolated fungi belonged to the genus Mortierella. Pikovskaya (PKO) medium, in which tricalcium phosphate was the sole phosphorus source, was used to screen strain L4 with the best phosphorus-solubilizing effect for further study. When the carbon source was glucose, the nitrogen source was ammonium chloride, the pH was 5, and the available phosphorus content was the highest. By exploring the possible mechanism of phosphorus release by phosphorus-solubilizing fungi, it was found that strain L4 produces several organic acids, such as oxalic acid, lactic acid, acetic acid, succinic acid, tartaric acid, malic acid, and citric acid. At 24 h, the alkaline phosphatase and acid phosphatase activities reached 154.72 mol/(L·h) and 120.99 mol/(L·h), respectively.

The plasmid-encoded lactose operon plays a vital role in the acid production rate of Lacticaseibacillus casei during milk beverage fermentation.

Lacticaseibacillus casei is used extensively in the fermented milk-beverage industry as a starter culture. Acid production capacity during fermentation is the main criterion for evaluating starters although it is strain-dependent. In this study, the acid production rates of 114 L. casei strains were determined and then classified into high acid (HC), medium acid (MC), and low acid (LC) groups. Comparative genomics analysis found that the lac operon genes encoding the phosphoenolpyruvate-lactose phosphotransferase system (PTSLac) were located on plasmids in the HC strains; however, it is notable that the corresponding operons were located on the chromosome in LC strains. Real-time PCR analysis showed that the copy numbers of lac operon genes in HC strains were between 3.1 and 9.3. To investigate the relationship between copy number and acid production rate, the lac operon cluster of the HC group was constitutively expressed in LC strains. The resulting copy numbers of lac operon genes were between 15.8 and 18.1; phospho-ß-galactosidase activity increased by 1.68-1.99-fold; and the acid production rates increased by 1.24-1.40-fold, which enhanced the utilization rate of lactose from 17.5 to 42.6% in the recombinant strains. The markedly increased expression of lac operon genes increased lactose catabolism and thereby increased the acid production rate of L. casei.

Two novel lactic acid bacteria, Limosilactobacillus fermentum MN-LF23 and Lactobacillus gasseri MN-LG80, inhibited Helicobacter pylori infection in C57BL/6 mice.

Helicobacter pylori (H. pylori) is one of the most prevalent pathogens globally, and long-term infection causes various gastrointestinal diseases such as gastritis and even cancer. In the present study, we screened dozens of lactic acid bacteria for the efficacy to inhibit H. pylori growth in vitro, and tested the therapeutic effects of candidate strains in vivo. The results showed that Limosilactobacillus fermentum MN-LF23 (LF23) and Lactobacillus gasseri MN-LG80 (LG80) significantly reduced the abundance of Helicobacter by 90% and 83% in the infected mice, respectively, and decreased the levels of serum urease and H. pylori-specific IgG. Both bacterial strains tended to ameliorate H. pylori infection-induced gastric mucosa damage and lymphocyte infiltration, and reduced levels of serum inflammatory cytokines such as TNF-α, IL-1ß, and IL-6. In addition, their culture supernatants also showed a therapeutic effect, as efficient as the bacterial cells. Furthermore, both strains significantly regulated gastric microbiota profile, and their supernatants restored the diversity of gastric microbiota. LF23 increased the abundance of Lactobacillus murinus and reduced the abundance of Desulfovibrio, whereas LG80 increased the abundance of Lactobacillus reuteri and reduced the abundance of Bilophila. Both LF23 and LG80 enriched beneficial commensals such as Faecalibaculum rodentium, and reduced detrimental bacteria such as H. pylori and Lachnoclostridium. In conclusion, we identified two novel lactic acid bacteria L. fermentum MN-LF23 and L. gasseri MN-LG80 that can remarkably inhibit H. pylori infection.

Difluoromethylation of Unactivated Alkenes Using Freon-22 through Tertiary Amine-Borane-Triggered Halogen Atom Transfer.

The application of abundant and inexpensive fluorine feedstock sources to synthesize fluorinated compounds is an appealing yet underexplored strategy. Here, we report a photocatalytic radical hydrodifluoromethylation of unactivated alkenes with an inexpensive industrial chemical, chlorodifluoromethane (ClCF2H, Freon-22). This protocol is realized by merging tertiary amine-ligated boryl radical-induced halogen atom transfer (XAT) with organophotoredox catalysis under blue light irradiation. A broad scope of readily accessible alkenes featuring a variety of functional groups and drug and natural product moieties could be selectively difluoromethylated with good efficiency in a metal-free manner. Combined experimental and computational studies suggest that the key XAT process of ClCF2H is both thermodynamically and kinetically favored over the hydrogen atom transfer pathway owing to the formation of a strong boron-chlorine (B-Cl) bond and the low-lying antibonding orbital of the carbon-chlorine (C-Cl) bond.

Sofosbuvir-velpatasvir-voxilaprevir in adolescents 12 to 17 years old with HCV infection.

BACKGROUND AND AIMS: Sofosbuvir-velpatasvir-voxilaprevir is a pangenotypic regimen for chronic HCV infection. In the USA and Europe, sofosbuvir-velpatasvir-voxilaprevir once daily for 12 weeks is indicated for adults who previously received an HCV NS5A inhibitor. In Europe, sofosbuvir-velpatasvir-voxilaprevir is also indicated in the absence of prior HCV direct-acting antiviral (DAA) therapy as an 8-week or 12-week regimen. In an open-label study, we evaluated the safety, efficacy, and pharmacokinetics of sofosbuvir-velpatasvir-voxilaprevir in adolescents 12 to 17 years with chronic HCV of any genotype. METHODS: In this Phase 2, multicenter study, sofosbuvir-velpatasvir-voxilaprevir 400/100/100 mg daily was administered to adolescents for 8 weeks if DAA-naïve or for 12 weeks for cirrhosis or prior DAA failure. The key efficacy endpoint was sustained virologic response 12 weeks after therapy (SVR12). Intensive pharmacokinetic sampling was done in 14 patients at week 2 or 4, and samples for population pharmacokinetics were collected in all patients. RESULTS: All patients (n = 21) were naïve to HCV DAAs, and none had cirrhosis. HCV genotype 3a infection was most common, occurring in 43% of patients. Overall, 100% of patients (21 of 21) reached SVR12. The most common adverse events were abdominal pain and headache (24% each) and nausea (19%); no adverse events led to discontinuation. The only serious adverse event, hypotension, was considered related to study drug and resolved the same day without interruption of treatment. Sofosbuvir-velpatasvir-voxilaprevir exposures were similar to those observed in adults. CONCLUSIONS: The pangenotypic regimen of sofosbuvir-velpatasvir-voxilaprevir is highly efficacious and well-tolerated in treating chronic HCV infection in adolescents.

Probiotic Bifidobacterium longum BB68S Improves Cognitive Functions in Healthy Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial.

Probiotics could improve cognitive functions in patients with neurological disorders such as Alzheimer's disease, but the effects on cognitive function in healthy older adults without cognitive impairment need further study. The purpose of this study was to investigate the effect of Bifidobacterium longum BB68S (BB68S) on cognitive functions among healthy older adults without cognitive impairment. A randomized, double-blind, placebo-controlled trial was conducted with 60 healthy older adults without cognitive impairment who were divided into probiotic or placebo groups and required to consume either a sachet of probiotic (BB68S, 5 × 1010 CFU/sachet) or placebo once daily for 8 weeks. The Montreal Cognitive Assessment (MoCA) was used as an inclusion screening tool to screen elderly participants with healthy cognitive function in our study, and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to assess cognitive function in subjects before and after intervention as an assessment tool. BB68S significantly improved subjects' cognitive functions (total RBANS score increased by 18.89 points after intervention, p < 0.0001), especially immediate memory, visuospatial/constructional, attention, and delayed memory domains. BB68S intervention increased the relative abundances of beneficial bacteria Lachnospira, Bifidobacterium, Dorea, and Cellulosilyticum, while decreasing those of bacteria related to cognition impairment, such as Collinsella, Parabacteroides, Tyzzerella, Bilophila, unclassified_c_Negativicutes, Epulopiscium, Porphyromonas, and Granulicatella. In conclusion, BB68S could improve cognitive functions in healthy elderly adults without cognitive impairment, along with having beneficial regulatory effects on their gut microbiota. This study supports probiotics as a strategy to promote healthy aging and advances cognitive aging research.

The Adhesion of Lactobacillus salivarius REN to a Human Intestinal Epithelial Cell Line Requires S-layer Proteins.

Lactobacillus salivarius REN, a novel probiotic isolated from Chinese centenarians, can adhere to intestinal epithelial cells and subsequently colonize the host. We show here that the surface-layer protein choline-binding protein A (CbpA) of L. salivarius REN was involved in adherence to the human colorectal adenocarcinoma cell line HT-29. Adhesion of a cbpA deletion mutant was significantly reduced compared with that of wild-type, suggesting that CbpA acts as an adhesin that mediates the interaction between the bacterium and its host. To identify the molecular mechanism of adhesion, we determined the crystal structure of a truncated form of CbpA that is likely involved in binding to its cell-surface receptor. The crystal structure identified CbpA as a peptidase of the M23 family whose members harbor a zinc-dependent catalytic site. Therefore, we propose that CbpA acts as a multifunctional surface protein that cleaves the host extracellular matrix and participates in adherence. Moreover, we identified enolase as the CbpA receptor on the surface of HT-29 cells. The present study reveals a new class of surface-layer proteins as well as the molecular mechanism that may contribute to the ability of L. salivarius REN to colonize the human gut.

Association between vitamin D and development of otitis media: A PRISMA-compliant meta-analysis and systematic review.

BACKGROUND: Nutrients related to serum vitamin D level were previously shown to be significantly associated with the risk of many chronic diseases. This study aimed to assess potential relationships between serum vitamin D level and otitis media (OM) risk. METHODS: PubMed, EMBASE, and Cochrane Library databases were searched till Aug 18, 2015 for studies of quantitative OM risk estimates in relation to serum vitamin D level. The odds ratio and weighted mean difference, with 95% confidence intervals (CIs), were used to measure the relationship between serum vitamin D level and OM risk. RESULTS: Of the 89 articles identified by database search, 5 studies reported data of 16,689 individuals were included in our meta-analysis. We noted participants with OM was associated with lower level of plasma vitamin D when compared with patients without OM (weighted mean difference -5.67; 95% CI -8.08 to -3.26, P < 0.001). Furthermore, as compared with control group, serum vitamin D level was not associated with the risk of OM (odds ratio 0.80, 95% CI 0.47-1.38, P = 0.425). Subgroup analyses suggested that participants with acute OM might associate with lower serum vitamin D level. CONCLUSIONS: Plasma vitamin D level might play an important role on the progression of acute OM, whereas no significant impact in patients with chronic OM.

Clinical efficacy and compliance of sublingual immunotherapy with Dermatophagoides farinae drops in patients with atopic dermatitis.

BACKGROUND: The oral route for administration of allergen immunotherapy has been explored since the 1900s. We attempted to evaluate the efficacy and safety of sublingual immunotherapy (SLIT) with Dermatophagoides farinae drops in patients with atopic dermatitis (AD) and investigate related factors influencing the patients' compliance. METHODS: A total of 107 patients with AD were randomized to receive either D. farinae drops plus pharmacotherapy (treatment group, n = 58) or only pharmacotherapy (control group, n = 49). Patients' compliance, the total effective rate, daily drug scores, visual analogue scale (VAS) scores, and IgG4 level were compared respectively between two groups at different time points. RESULTS: Twenty-three cases have withdrawn from the study. The total effective rate in the treatment group (77.78%) was significantly higher than the control group (53.85%) (P < 0.05). The treatment group was significantly reduced in daily drug scores and VAS scores compared with the control group at 12 months follow-up. Meanwhile, at the end of therapy, a significant difference was found in the change in average daily drug scores (difference from 1 month) between two groups (P < 0.01); The treatment group evidently had a higher level of serum-specific IgG4 than the control group at 6 and 12 month of treatment (P < 0.05). CONCLUSION: Dermatophagoides farinae drops are a safe and effective SLIT for patients with AD, which was proven to reduce the need for medicine. In addition, SLIT could induce a tolerogenic IgG4 response to mite allergen correlated with favorable clinical efficacy. Standardization of specific immunotherapy is essential to ensure therapeutic efficacy and compliance.

Parimary culture of schwann cell / 대한이비인후과학회지

No abstract available.

A study on catecholamine concentrations in the perilymph and the CSF of normal guinea pig / 대한이비인후과학회지

No abstract available.

A case of traumatic cerebrospinal fluid otorhinorrhea with congenital cholesteatoma / 대한이비인후과학회지

No abstract available.

A clinical study on the prognostic factors of tympanoplasty usingpostoperative tympanogram in chronic otitis media / 대한이비인후과학회지

No abstract available.

Ultrastructural study of the respiratory mucous membrane of rabbit exposed to antracite coal briquette gas / 대한이비인후과학회지

No abstract available.