Silver nanoparticle-deposited whey protein isolate amyloid fibrils as catalysts for the reduction of methylene blue

The unique structural characteristics and superior biocompatibility make the protein nanofibers promising immobilization platforms/substrates for catalysts/enzymes. Metal nanoparticles have been employed as the catalysts in industries due to their excellent catalytic activity and stability, whereas their high surface energy leads to nanoparticle aggregation, thereby hampering their catalytic performance. Here, amyloid fibril (AF) derived from whey protein isolate (WPI) was chosen as the support of silver nanoparticles (AgNP) and utilized for the catalytic reduction of methylene blue (MB). The one-dimensional amyloid-based hybrid materials (AgNP/WPI-AF) were first synthesized via chemical or photochemical route. The characterization of AgNP/WPI-AF by UV-vis spectrophotometry and electron microscopy revealed that the sizes of AgNP on WPI-AF's surface ranged from 2 to 30 nm. Next, the catalytic performances of AgNP/WPI-AF prepared by various routes for MB degradation were investigated. Additionally, the kinetic data were analyzed using two different models and the apparent rate constants and thermodynamic parameters were further determined accordingly. Moreover, the reusability of AgNP/WPI-AF was assessed by monitoring the percentage removal of MB over consecutive filtering cycles. Our results indicated that Langmuir-Hinshelwood-type mechanism better described the catalytic MB reduction using AgNP/WPI-AF. This work provides a nice example of application of nanoparticle-amyloid fibril composite materials for catalysis.

Green synthesis of gold nanoparticle/gelatin/protein nanogels with enhanced bioluminescence/biofluorescence

Here we report the green synthesis of gelatin/protein hybrid nanogels containing gold nanoparticles (AuNPs) that collectively exhibit metal-enhanced luminescence/fluorescence (MEL/MEF). The gelatin/protein nanogels, prepared by genipin cross-linking of preformed gelatin/protein polyion complexes (PICs), exhibited sizes ranging between 50 and 200 nm, depending on the weight ratio of gelatin and protein. These nanogels serve as reducing and stabilizing agents for the AuNPs, allowing for nucleation in a gel network that exhibits colloidal stability and MEL/MEF. AuNP/gelatin/HRP and AuNP/gelatin/LTF nanogels presented an ~11-fold enhancement of bioluminescence in an HRP-luminol system and a ~50-fold fluorescence enhancement when compared to free LTF in cell uptake experiments. These hybrid nanogels show promise for optically enhanced diagnosis and other therapeutic applications.

An efficient Photobioreactors/Raceway circulating system combined with alkaline-CO2 capturing medium for microalgal cultivation

High efficiency of microalgal growth and CO₂ fixation in a Photobioreactors (PBRs)/Raceway circulating (PsRC) system combined with alkaline-CO₂ capturing medium and operation was established and investigated. Compared with a pH 6 medium, the average biomass productivity of Chlorella sp. AT1 cultured in a pH 11 medium at 2 L min^-1 circulation rate for 7 days increased by about 2-fold to 0.346 g L^-1 d^-1. The maximum amount of CO₂ fixation and CO₂ utilization efficiency of Chlorella sp. AT1 could be obtained at a PBRs to Raceway ratio of 1:10 in an indoor-simulated PsRC system. A similar result was also shown in an outdoor PsRC system with a 10-ton scale for microalgal cultivation. Under the appropriate circulation rate, the stable growth performance of Chlorella sp. AT1 cultured by long-term semi-continuous operation in the 10-ton outdoor PsRC system was observed, and the total amount of CO₂ fixation was approximately 1.2 kg d^-1 with 50% CO₂ utilization efficiency.

Pilot scale repeated fed-batch fermentation processes of the wine yeast Dekkera bruxellensis for mass production of resveratrol from Polygonum cuspidatum

Resveratrol has long been used as an ingredient in functional foods. Currently, Polygonum cuspidatum extract is the greatest natural source for resveratrol because of high concentrations of glycosidic-linked resveratrol. Thus, developing a cost-effective procedure to hydrolyze glucoside could substantially enhance resveratrol production from P. cuspidatum. This study selected Dekkera bruxellensis from several microorganisms based on its bioconversion and enzyme-specific activities. We demonstrated that the cells could be reused at least nine times while maintaining an average of 180.67U/L β-glucosidase activity. The average resveratrol bioconversion efficiency within five rounds of repeated usage was 108.77±0.88%. This process worked effectively when the volume was increased to 1200L, a volume at which approximately 35mgL^-1h^-1 resveratrol per round was produced. This repeated fed-batch bioconversion process for resveratrol production is comparable to enzyme or cell immobilization strategies in terms of reusing cycles, but without incurring additional costs for immobilization.

Ability of an alkali-tolerant mutant strain of the microalga Chlorella sp. AT1 to capture carbon dioxide for increasing carbon dioxide utilization efficiency

An alkali-tolerant Chlorella sp. AT1 mutant strain was screened by NTG mutagenesis. The strain grew well in pH 6-11 media, and the optimal pH for growth was 10. The CO₂ utilization efficiencies of Chlorella sp. AT1 cultured with intermittent 10% CO₂ aeration for 10, 20 and 30min at 3-h intervals were approximately 80, 42 and 30%, respectively. In alkaline medium (pH=11) with intermittent 10% CO₂ aeration for 30min at 3-, 6- and 12-h intervals, the medium pH gradually changed to 10, and the biomass productivities of Chlorella sp. AT1 were 0.987, 0.848 and 0.710gL^-1d^-1, respectively. When Chlorella sp. AT1 was aerated with 10% CO₂ intermittently for 30min at 3-h intervals in semi-continuous cultivation for 21days, the biomass concentration and biomass productivity were 4.35gL^-1 and 0.726gL^-1d^-1, respectively. Our results show that CO₂ utilization efficiency can be markedly increased by intermittent CO₂ aeration and alkaline media as a CO₂-capturing strategy for alkali-tolerant microalga cultivation.

[A preliminary study of the treatment of chronic tinnitus in menopausal women]

Objective:To explore the hormone treatment outcome of the menopause related tinnitus.Method:From April 2016 to October 2016, Fifty-nine patients who were diagnosed with menopausal syndrome in the menopause clinics of Beijing Shijitan Hospital were enrolled in our study, and questionnaire-based investigation about tinnitus and menopause was performed. According to the patients' intention, they were divided into treatment group and control group. Age, BMI, menopausal KMI scores, severity of tinnitus were statistically analyzed. After 3 months follow up, the different therapeutic effects of tinnitus between two groups were analyzed. Result:There was no significant difference between two groups in age, BMI, menopausal KMI scores and severity of tinnitus. The tinnitus in untreated patients after 3 months follow up showed no improvement, while 5 cases had been cured in treatment group. Conclusion:Menopause related tinnitus was an independent type of tinnitus. Menopausal hormone therapy can be applied for treatment after excluding other tinnitus risk factors.

Characterization of an extracellular β-glucosidase from Dekkera bruxellensis for resveratrol production

Polygonum cuspidatum is a widely grown crop with a rich source of polydatin (also called piceid) for resveratrol production. Resveratrol is produced from piceid via enzymatic cleavage of the sugar moiety of piceid. In this study, Dekkera bruxellensis mutants were selected based on their high p-nitrophenyl-β-d-glucopyranoside and piceid conversion activities. The enzyme responsible for piceid conversion was a heterodimeric protein complex that was predominantly secreted to the extracellular medium and consisted of two subunits at an equal ratio with molecular masses of 30.5 kDa and 48.3 kDa. The two subunits were identified as SCW4p and glucan-β-glucosidase precursor in D. bruxellensis. Both proteins were individually expressed in Saccharomyces cerevisiae exg1Δ mutants, which lack extracellular β-glucosidase activity, to confirm each protein’s enzymatic activities. Only the glucan-β-glucosidase precursor was shown to be a secretory protein with piceid deglycosylation activity. Our pilot experiments of piceid bioconversion demonstrate the possible industrial applications for this glucan-β-glucosidase precursor in the future.

Simultaneous microalgal biomass production and CO2 fixation by cultivating Chlorella sp. GD with aquaculture wastewater and boiler flue gas

A microalgal strain, Chlorella sp. GD, cultivated in aquaculture wastewater (AW) aerated with boiler flue gas, was investigated. When AW from a grouper fish farm was supplemented with additional nutrients, the microalgal biomass productivity after 7days of culture was 0.794gL^-1d^-1. CO₂ fixation efficiencies of the microalgal strains aerated with 0.05, 0.1, 0.2, and 0.3vvm of boiler flue gas (containing approximately 8% CO₂) were 53, 51, 38, and 30%, respectively. When the microalgal strain was cultured with boiler flue gas in nutrient-added AW, biomass productivity increased to 0.892gL^-1d^-1. In semi-continuous cultures, average biomass productivities of the microalgal strain in 2-day, 3-day, and 4-day replacement cultures were 1.296, 0.985, and 0.944gL^-1d^-1, respectively. These results demonstrate the potential of using Chlorella sp. GD cultivations in AW aerated with boiler flue gas for reusing water resources, reducing CO₂ emission, and producing microalgal biomass.

Cultivation of Chlorella sp. GD using piggery wastewater for biomass and lipid production

The development of a culture system for Chlorella sp. GD to efficiently produce biomass and oil for biodiesel production was investigated. Chlorella sp. GD was cultivated with 0%, 25%, 50%, 75% and 100% piggery wastewater (diluted by medium) at 300 μmol m(-2) s(-1), a 2% CO2 aeration rate of 0.2 vvm and 26±1°C; after a 10-day culture in batch cultures, the maximum specific growth rate and biomass productivity of the microalga obtained in 100% piggery wastewater were 0.839 d(-1) and 0.681 g L(-1) d(-1), respectively. The highest lipid content and lipid productivity were 29.3% and 0.155 g L(-1) d(-1) at 25% wastewater, respectively. In semi-continuous cultures, the biomass and lipid productivities with 25-75% wastewater ratios were greater than 0.852 and 0.128 g L(-1) d(-1), respectively. These results show that Chlorella sp. GD grows efficiently in piggery wastewater, and that a stable growth performance was achieved for long-term microalgal cultivation in a semi-continuous culture.

Inhibitory effect of olive oil on fibrosis induced by carbon tetrachloride in rat liver

BACKGROUND & AIMS

In this study, the inhibitory effect of olive oil on liver fibrosis induced by carbon tetrachloride (CCl(4)) has been investigated in rats.

METHODS

Rats were divided randomly into four groups: control, CCl(4), and two olive oil groups. Except for rats in the control group, all rats were orally administered CCl(4) twice a week for 8 weeks. Rats in the olive oil groups were treated daily with olive oil (2 or 10 ml/kg) through gastrogavage for the entire experimental period.

RESULTS

RT-PCR analysis showed that CCl(4) increased the hepatic mRNA expressions of lipopolysaccharide binding protein, CD14, Toll-like receptor-4, NADPH oxidase, nuclear factor-kappa beta, collagen (alpha1) (I), collagen (alpha1) (III), and transforming growth factor beta1. The expression of these mRNAs could be decreased by olive oil treatment. In addition, Western blot analysis also supported these results. CCl(4)-induced liver damage, as characterized by the increase in hepatic malondialdehyde and hydroxyproline levels. Olive oil treatment decreased the hepatic malondialdehyde and hydroxyproline levels. Histological evaluations showed that olive oil could attenuate the liver fibrosis, necrosis, and expression of smooth muscle alpha-actin that are induced by CCl(4).

CONCLUSION

It is speculated that the phenolic compounds in olive oil significantly reduced CCl(4)-induced hepatic fibrosis in rats.

Maleimide and maleic anhydride derivatives from the mycelia of Antrodia cinnamomea and their nitric oxide inhibitory activities in macrophages

On cultivation of the fungus Antrodia cinnamomea (BCRC 36799) on a medium, the mycelium was extracted and evaluated for nitric oxide (NO) inhibitory activity. Bioactivity-directed fractionation led to the isolation of two new maleimide derivatives, antrocinnamomins A (1) and B (2), and two new maleic anhydride derivatives, antrocinnamomins C (3) and D (4), along with three known compounds, 3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]furan-2,5-dione (5), 3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]-1H-pyrrole-2,5-dione (6), and 3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]-1H-pyrrol-1-ol-2,5-dione (7). Structural elucidation of compounds 1-4 was carried out by spectroscopic data. Compound 1 displayed significant inhibitory effect on nitric oxide (NO) production.

Diagnostic accuracy of a stereotaxically guided vacuum-assisted large-core breast biopsy program in Canada

OBJECTIVE

To assess the accuracy rate associated with 11-gauge vacuum assisted large-core breast biopsy (VALCBB) at our institution.

METHODS

673 consecutive VALCBBs performed between September 1997 and March 2000 were evaluated. For most of the benign VALCBB specimens, accuracy was determined by the stability of the lesions on follow-up mammography. When possible, histological results of specimens obtained from VALCBB and of specimens obtained from surgical excision were compared. Modified accuracy rates were calculated.

RESULTS

Of the 673 biopsies, 499 (74%) were benign; for the 315 benign lesions for which complete follow-up information was available, a greater than 99% modified accuracy rate was obtained. The modified accuracy rate for the 174 nonbenign lesions was 95%. Thus, VALCBB yielded an overall modified accuracy for both benign and nonbenign lesions of 97.9%.

CONCLUSION

VALCBB provides accurate histological results for biopsy of suspicious lesions of the breast.

Vacuum-assisted large-core breast biopsy: complications and their incidence

OBJECTIVE

To assess both the rate and types of complications associated with vacuum-assisted large-core breast biopsy (VALCBB) at our institution.

METHODS

Three hundred and four VALCBBs performed in 297 patients between Sept. 18, 1997, and Mar. 30, 1999, were evaluated. Complications associated with VALCBB were assessed at the time of the procedure and in the post-procedure period. Adverse outcomes included pain, bleeding or bruising, and hematoma. Complications were also classified in terms of minor, significant, and major severity.

RESULTS

VALCBB yielded non-minor (i.e., significant and major) complication rates of 3.9% during the procedure and 3.6% in the post-procedure period, with only 2 complications (vasovagal-induced seizure and migraine) that required treatment.

CONCLUSION

With proper technique and patient preparation, VALCBB is a very safe procedure with a low complication rate.