Enhanced production, purification, and characterization of propionicin PLG-1, a bacteriocin produced by Propionibacterium thoenii P127

Propionibacterium thoenii strain P127 produces the bacteriocin propionicin PLG-1. Goals of this study were to increase the sensitivity of the standard well diffusion assay system for bacteriocin activity, to improve production of propionicin PLG-1 under controlled conditions in a fermenter, and to obtain the amino acid sequence and composition of the purified bacteriocin;For the well diffusion assay, a 5-mm deep base layer that contained 2.5% agar, 0.85% NaCl and 0.1% Tween 80 was used. Plates were incubated at 37° C for 2 h before adding bacteriocin samples to the wells. Lactobacillus delbrueckii ATCC 4797 was used as indicator strain, rather than Propionibacterium acidipropionici P5. Large, clear zones of inhibition could be measured after 12 h of incubation. Recovery of bacteriocin from the culture supernatant was improved by adding 0.1% Tween 80 to buffer used for dialysis and resuspension of precipitated protein;Bacteriocin production was compared in six different media under controlled conditions in a fermenter: 12.5% beet molasses; 9% corn steep liquor; combinations of these media at 1:3, 1:1, and 3:1 vol:vol ratios; and the standard growth medium, sodium lactate broth. Cell populations reached 10[superscript]9 cells/ml in all media. Maximum production of propionicin PLG-1 was obtained in 3:1 beet molasses:corn steep liquor, and was 5 times greater than in sodium lactate broth. Measurable activity was detected after 4 days of culture incubation;Fed-batch fermentations were conducted for 21 days in sodium lactate broth with regular feedings of sodium lactate. Average concentrations of viable cells were higher than in batch fermentations: 2.2 x10[superscript]9 cells/ml vs. 3.7 x10[superscript]8 cells/ml. Propionic acid concentrations were in excess of 30 g/l and acetic acid concentrations were over 10 g/l by the end of fed-batch fermentation. Bacteriocin activity ranged between 100 and 184 AU/ml in three fed-batch fermentations; in contrast 8 AU/ml was the highest titer obtained in batch fermentation. After reaching its maximum value at 16-17 days, bacteriocin activity dropped sharply with continued incubation. This suggests production of an inhibitor or of proteolytic activity;Propionicin PLG-1 was purified to homogeneity by precipitation with 75% saturated ammonium sulfate followed by ion exchange column chromatography and reversed-phase high-performance liquid chromatography. According to amino acid composition analysis, propionicin PLG-1 is composed of 99 amino acid residues, of which 42% are hydrophobic (Ala, Ile, Leu, Val, and Pro); calculated molecular weight is 9,328 d. The N-terminal amino acid sequence is: NH[subscript]2-[superscript]1Asn-[superscript]2Val-[superscript]3Asp-[superscript]4Ala(Thr)-[superscript]5 Arg-[superscript]6Thr(Cys)-[superscript]7Ala(Thr)-[superscript]8Arg[superscript]9Thr(Ala)-[superscript]1 0 Pro. No homology of this sequence to sequences of other bacteriocins from lactic acid bacteria was seen in a search of the SWISS-PROT data bank

Addition of Garlic or Onion before Irradiation on Lipid Oxidation, Volatiles and Sensory Characteristics of Cooked Ground Beef

Addition of 0.5% onion was effective in reducing lipid oxidation in irradiated cooked ground beef after 7 d storage. Addition of garlic or onion greatly increased the amounts of sulfur volatiles from cooked ground beef. Irradiation and storage both changed the amounts and compositions of sulfur compounds in both garlic- and onion-added cooked ground beef significantly. Although, addition of garlic and onion produced large amounts of sulfur compounds, the intensity of irradiation odor and irradiation flavor in irradiated cooked ground beef was similar to that of the nonirradiated control. Addition of garlic (0.1%) or onion (0.5%) to ground beef produced garlic/onion aroma and flavor after cooking, and the intensity was stronger with 0.1% garlic than 0.5% onion treatment. Considering the sensory results and the amounts of sulfur compounds produced in cooked ground beef with added garlic or onion, 0.5% of onion or less than 0.1% of garlic is recommended to mask or change irradiation off-odor and off-flavor

Effect of Garlic, Onion, and their Combination on the Quality and Sensory Characteristics of Irradiated Raw Ground Beef

Irradiated raw ground beef had lower a*- and b*-valuesthan nonirradiated ones regardless of garlic or onion treatment at 0 d. Irradiation increased TBARS values of control ground beef, but addition of 0.5% onion or 0.1% garlic + 0.5% onion reduced oxidative changes during storage. Addition of garlic or onion greatly increased the amounts of sulfur compounds, but the increase was greater with garlic. With irradiation, the profiles and amounts of Svolatiles in raw ground beef changed significantly. However,the intensity of irradiation aroma in irradiated raw ground beef with garlic or onion was similar to that of the nonirradiated control. This indicated that some of the sulfur compounds unique to garlic or onion interacted with common sulfur compounds detected in irradiated meat and masked or changed the odor characteristics of irradiated raw ground beef. It was concluded that \u3e 0.5% onion or \u3c 0.01% garlic would be needed to mask or prevent irradiation aromain irradiated raw ground beef

Antimicrobial Effect of 7-O-Butylnaringenin, a Novel Flavonoid, and Various Natural Flavonoids against Helicobacter pylori Strains

Abstract: The antimicrobial effect of a novel flavonoid (7-O-butylnaringenin) on Helicobacter pylori 26695, 51, and SS1 strains and its inhibitory effect on the urease activity of the strains were evaluated and compared with those of several natural flavonoids. First, various flavonoids were screened for antimicrobial activities using the paper disc diffusion method. Hesperetin and naringenin showed the strongest antimicrobial effects among the natural flavonoids tested, and thus hesperetin and naringenin were selected for comparison with 7-O-butylnaringenin. The antimicrobial effect of 7-O-butylnaringenin was greater than that of the hesperetin and naringenin. H. pylori 51 was more sensitive to 7-O-butylnaringenin (2 log reduction of colony forming units, p \u3c 0.05) than the other two strains at 200 μM. 7-O-Butylnaringenin also showed the highest inhibitory effect against urease activity of H. pylori. Morphological changes of H. pylori 26695 treated with these flavonoids indicated that both hesperetin and 7-O-butylnaringenin at 200 μM damaged the cell membranes

Anti-fibrotic effect of bovine colostrum in carbon tetrachloride-induced hepatic fibrosis

Purpose To investigate the preventive effect of colostrum on hepatic fibrosis induced by carbon tetrachloride (CCl4) in mice. Methods Seven-week-old male Balb/C mice were treated with CCl4 with or without a diet of bovine colostrum (BC) for 2 weeks. Hepatic fibrosis was determined using Sirius red staining, α-smooth muscle actin (α-SMA) immunohistochemistry, immunoblot analysis, and quantitative polymerase chain reaction (PCR) for profibrogenic and proinflammatory genes. Hepatocellular injury was assessed through the measurement of serum alanine aminotransferase (ALT) levels. Results Compared to the CCl4 group, the BC4 group had a 55% reduction in fibrosis as demonstrated by Sirius red staining. The BC+CCl4 group also had a significant reduction in α-SMA expression according to immunohistochemistry and immunoblot. On quantitative PCR, the BC+CCl4 group showed significant 8.42-, 21.11-, 0.57-, and 2.90-fold reductions in the expression of Acta2, Col1α1, Tgfβ1, and Tnf-α, respectively, compared to the CCl4 group. The serum ALT level was significantly reduced in the BC+CCl4 group compared to the CCl4 group. Conclusion The present study demonstrated that BC ameliorated CCl4-induced hepatic fibrosis by inhibiting fibrogenesis-related gene expression and also decreased CCl4-induced hepatocyte injury. Therefore, BC might be therapeutically efficacious in preventing hepatic fibrosis in various liver diseases

Improved accuracy of intraocular lens power calculation by preoperative management of dry eye disease

Background To evaluate the effects of pretreatment for dry eye disease (DED) on the accuracy of intraocular lens (IOL) power calculation. Methods Patients who underwent uneventful cataract surgery were included in the study. IOL power was determined using the SRK/T and Barrett Universal II (Barrett) formulas. The patients were divided into non-pretreatment and pretreatment groups, and those in the pretreatment group were treated with topical 0.5% loteprednol etabonate and 0.05% cyclosporin A for 2 weeks prior to cataract surgery. Ocular biometry was performed in all groups within 2 days before surgery. The mean prediction error, mean absolute error (MAE), and proportions of refractive surprise were compared between the non-pretreatment and pretreatment groups at 1 month postoperatively. Refractive surprise was defined as MAE ≥ 0.75D. Results In a total of 105 patients, 52 (52 eyes) were in the non-pretreatment group and 53 (53 eyes) in the pretreatment group. The MAE was 0.42 ± 0.33, 0.38 ± 0.34 (SRK/T, Barrett) and 0.23 ± 0.19, 0.24 ± 0.19 in the non-pretreatment and pretreatment groups, respectively (p < 0.001/=0.008). The number of refractive surprises was also significantly lower in the pretreatment group. [non-pretreatment/pretreatment: 9/2 (SRK/T); 8/1 (Barrett); p = 0.024/0.016]. Pretreatment of DED was related to a reduction in postoperative refractive surprise. [SRK/T/Barrett: OR = 0.18/0.17 (95% CI: 0.05–0.71/0.05–0.60), p = 0.014/0.006]. Conclusions The accuracy of IOL power prediction can be increased by actively treating DED prior to cataract surgery.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF-2020R1C1C1007372)

Successful Treatment of Malignant Superior Vena Cava Syndrome Using a Stent-Graft

We report successful outcomes after endovascular placement of a stent graft in a 74- and a 77-year-old men, both of whom had malignant superior vena cava syndrome caused by squamous cell carcinoma. In each patient, successful palliation of the malignant superior vena cava syndrome was achieved by placement of a stent graft. No procedure-related complications were observed. The patients were asymptomatic until their deaths, seven and 14 months after stent graft placement, respectively