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1.
Objectives
To investigate the contribution of direct electron transfer mechanisms to electricity production in microbial fuel cells by physically retaining Shewanella oneidensis cells close to or away from the anode electrode.Results
A maximum power output of 114 ± 6 mWm?2 was obtained when cells were retained close to the anode using a dialysis membrane. This was 3.5 times more than when the cells were separated away from the anode. Without the membrane the maximum power output was 129 ± 6 mWm?2. The direct mechanisms of electron transfer contributed significantly to overall electron transfer from S. oneidensis to electrodes, a result that was corroborated by another experiment where S. oneidensis cells were entrapped in alginate gels.Conclusion
S. oneidensis transfers electrons primarily by direct electron transfer as opposed to mediated electron transfer.2.
Objectives
To improve H2 production, the green algae Chlamydomonas reinhardtii cc849 was co-cultured with Azotobacter chroococcum.Results
The maximum H2 production of the co-culture was 350% greater than that of the pure algal cultures under optimal H2 production conditions. The maximum growth and the respiratory rate of the co-cultures were about 320 and 300% of the controls, and the dissolved O2 of co-cultures was decreased 74%. Furthermore, the in vitro maximum hydrogenase activity of the co-culture was 250% greater than that of the control, and the in vivo maximum hydrogenase activity of the co-culture was 1.4-fold greater than that of the control. In addition, the maximum starch content of co-culture was 1400% that of the control.Conclusions
Azotobacter chroococcum improved the H2 production of the co-cultures by decreasing the O2 content and increasing the growth and starch content of the algae and the hydrogenase activity of the co-cultures relative to those of pure algal cultures.3.
Objectives
To investigate the feasibility of coupling carbonyl cyanide m-chlorophenylhydrazone-regulated photohydrogen production by Tetraselmis subcordiformis in a photobioreactor to an alkaline fuel cell (AFC).Results
H2 evolution kinetics in the AFC integrated process was characterized. The duration of H2 evolution was prolonged and its yield was improved about 1.5-fold (to 78 ± 5 ml l?1) compared with that of the process without AFC. Improved H2 yield was possibly caused by removal of H2 feedback inhibition by H2 consumption in situ. Decreases in the H2 production rate correlated with the gradual deactivation of PSII and hydrogenase activities. The H2 yield was closely associated with catabolism of starch and protein.Conclusion
A marine green algal CO2-supplemented culture integrated with in situ H2-consumption by an AFC system was developed as a viable protocol for the H2 production.4.
Tatyana Laurinavichene Kestutis Laurinavichius Evgeny Shastik Anatoly Tsygankov 《Biotechnology letters》2018,40(2):309-314
Objectives
To prove the possibility of efficient starch photofermentation in co-culture of heterotrophic and phototrophic bacteria over prolonged period.Results
Repeated batch photofermentation of starch was demonstrated in co-culture Clostridium butyricum and Rhodobacter sphaeroides under microaerobic conditions. It continued 15 months without addition of new inoculum or pH regulation when using 4–5 g starch l?1 and 0.04 g yeast extract l?1. The complete degradation of starch without volatile fatty acids accumulation was shown in this co-culture. The average H2 yield of 5.2 mol/mol glucose was much higher than that in Clostridium monoculture. The species composition of co-culture was studied by q-PCR assay. The concentration of Clostridium cells in prolonged co-culture was lower than in monoculture and even in a single batch co-culture. This means that Clostridia growth was significantly limited whereas starch hydrolysis still took place.Conclusion
The prolonged repeated batch photofermentation of starch by co-culture C. butyricum and R. sphaeroides provided efficient H2 production without accumulation of organic acids under conditions of Clostridia limitation.5.
Objectives
To improve the quality of diesel fuel via removal of aromatic compounds using Pseudomonas sp.Results
In the present study Pseudomonas sp. was able to remove 94% of fluorene, 59% of phenanthrene, 49% of anthracene, 52% of fluoranthene, 45% of pyrene and 75% carbazole present in diesel oil. Additionally, it also does not affect the aliphatic content of fuel thus maintaining the carbon backbone of the fuel.Conclusions
Pseudomonas sp. is a potential biocatalyst that can be used in the refining industry.6.
Objective
To explore the glycerol utilization pathway in Corynebacterium glutamicum for succinate production under O2 deprivation.Result
Overexpression of a glycerol facilitator, glycerol dehydrogenase and dihydroxyacetone kinase from Escherichia coli K-12 in C. glutamicum led to recombinant strains NC-3G diverting glycerol utilization towards succinate production under O2 deprivation. Under these conditions, strain NC-3G efficiently consumed glycerol and produced succinate without growth. The recombinant C. glutamicum utilizing glycerol as the sole carbon source showed higher intracellular NADH/NAD+ ratio compare with utilizing glucose. The mass conversion of succinate increased from 0.64 to 0.95. Using an anaerobic fed-batch fermentation process, the final strain produced 38.4 g succinate/l with an average yield of 1.02 g/g.Conclusions
The metabolically-engineered strains showed an efficient succinate production using glycerol as sole carbon source under O2 deprivation.7.
Yuan Wang Xue-Yin Zhang Yan-Ling Luo Feng Xu Ya-Shao Chen Yu-Yu Su 《Journal of nanobiotechnology》2017,15(1):76
Background
Stimuli-responsive polymer materials are a new kind of intelligent materials based on the concept of bionics, which exhibits more significant changes in physicochemical properties upon triggered by tiny environment stimuli, hence providing a good carrier platform for antitumor drug delivery.Results
Dual stimuli-responsive Fe3O4 graft poly(acrylic acid)-block-poly(2-methacryloyloxyethyl ferrocenecarboxylate) block copolymers (Fe3O4-g-PAA-b-PMAEFC) were engineered and synthesized through a two-step sequential reversible addition-fragmentation chain transfer polymerization route. The characterization was performed by FTIR, 1H NMR, SEC, XRD and TGA techniques. The self-assembly behavior in aqueous solution upon triggered by pH, magnetic and redox stimuli was investigated via zeta potentials, vibration sample magnetometer, cyclic voltammetry, fluorescent spectrometry, dynamic light scattering, XPS, TEM and SEM measurements. The experimental results indicated that the Fe3O4-g-PAA-b-PMAEFC copolymer materials could spontaneously assemble into hybrid magnetic copolymer micromicelles with core–shell structure, and exhibited superparamagnetism, redox and pH stimuli-responsive features. The hybrid copolymer micromicelles were stable and nontoxic, and could entrap hydrophobic anticancer drug, which was in turn swiftly and effectively delivered from the drug-loaded micromicelles at special microenvironments such as acidic pH and high reactive oxygen species.Conclusion
This class of stimuli-responsive copolymer materials is expected to find wide applications in medical science and biology, etc., especially in drug delivery system.8.
Godwin E. Oyiwona James Ogbonna Chukwudi Uzoma Anyanwu So Ishizaki Zen-ichiro Kimura Satoshi Okabe 《Biotechnology letters》2017,39(2):253-259
Objective
To investigate a syntrophic interaction between Geobacter sulfurreducens and hydrogenotrophic methanogens in sludge-inoculated microbial fuel cell (MFC) systems running on glucose with an improved electron recovery at the anode.Results
The presence of archaea in MFC reduces Coulombic efficiency (CE) due to their electron scavenging capability but, here, we demonstrate that a syntrophic interaction can occur between G. sulfurreducens and hydrogenotrophic methanogens via interspecies H2 transfer with improvement in CE and power density. The addition of the methanogenesis inhibitor, 2-bromoethanesulfonate (BES), resulted in the reduction in power density from 5.29 to 2 W/m3, and then gradually increased to the peak value of 5.5 W/m3 when BES addition was stopped.Conclusion
Reduction of H2 partial pressure by archaea is an efficient approach in improving power output in a glucose-fed MFC system using Geobacter sp. as an inoculum.9.
Na Du Shumin Liu Min Niu Yong Duan Shuangmeng Zhang Jing Yao Jian Mao Ran Chen Yan Du 《Annals of clinical microbiology and antimicrobials》2017,16(1):58
Background
In recent years, New Delhi metallo-beta-lactamases 1 (bla NDM-1) has been reported with increasing frequency and become prevalent. The present study was undertaken to investigate the epidemiological dissemination of the bla NDM-1 gene in Enterobacter cloacae isolates at a teaching hospital in Yunnan, China.Methods
Antimicrobial susceptibility testing was performed using VITEK 2 system and E test gradient strips. The presence of integrons and insertion sequence common region 1 were examined by PCR and sequencing. Clonal relatedness was assessed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Conjugation experiments and Southern blot hybridization were performed to determine the transferability of plasmids.Results
Ten E. cloacae isolates and their Escherichia coli transconjugants were exhibited similar resistant patterns to carbapenems, cephalosporins and penicillins. 8 (80%) of E. cloacae isolates carried class 1 integron and 1 (12.5%) carried class 2 integron. Integron variable regions harbored the genes which encoded resistance to aminoglycosides (aadA1, aadA2, aadA5, aadB, aac(6′)-Ib-cr), sulfamethoxazole/trimethoprim (dfrA17, dfrA12, dfrA15) and Streptozotocin (sat2). Six E. cloacae isolates belonged to ST74 and exhibited highly similar PFGE patterns. Each isolate shared an identical plasmid with ~33.3 kb size that carried the bla NDM-1 gene, except T3 strain, of which the bla NDM-1 gene was located on a ~50 kb plasmid.Conclusions
Our findings suggested that plasmid was able to contribute to the dissemination of bla NDM-1. Hence, more attention should be devoted to monitor the dissemination of the bla NDM-1 gene due to its horizontal transfer via plasmid. In addition, nosocomial surveillance system should actively monitor the potential endemic clone of ST74 to prevent their further spread.10.
Korey J. Brownstein Mahmoud Gargouri William R. Folk David R. Gang 《Metabolomics : Official journal of the Metabolomic Society》2017,13(11):133
Introduction
Botanicals containing iridoid and phenylethanoid/phenylpropanoid glycosides are used worldwide for the treatment of inflammatory musculoskeletal conditions that are primary causes of human years lived with disability, such as arthritis and lower back pain.Objectives
We report the analysis of candidate anti-inflammatory metabolites of several endemic Scrophularia species and Verbascum thapsus used medicinally by peoples of North America.Methods
Leaves, stems, and roots were analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and partial least squares-discriminant analysis (PLS-DA) was performed in MetaboAnalyst 3.0 after processing the datasets in Progenesis QI.Results
Comparison of the datasets revealed significant and differential accumulation of iridoid and phenylethanoid/phenylpropanoid glycosides in the tissues of the endemic Scrophularia species and Verbascum thapsus.Conclusions
Our investigation identified several species of pharmacological interest as good sources for harpagoside and other important anti-inflammatory metabolites.11.
Xueman Huang Shirong Liu Yeming You Yuanguang Wen Hui Wang Jingxin Wang 《Plant and Soil》2017,414(1-2):199-212
Background and aims
Microbial communities and their associated enzyme activities affect the quantity and chemical quality of carbon in soil. We aimed to evaluate the biochemical mechanisms underlying how N2-fixing species influences soil organic carbon chemical composition through soil microbial functional groups and enzyme activities.Methods
We examined the effects of N2-fixing species mixed with Eucalyptus on soil carbon storage, and the chemical composition of an 8-year-old pure Eucalyptus urophylla plantation (PP) and a mixed E.urophylla and Acacia mangium plantation (MP).Results
The soil carbon stock and recalcitrant carbon chemical component significantly increased in surface soil in MP. The total PLFAs and bacterial PLFAs increased by 29.1% and 27.0% in cool-dry season, while in the warm-wet season, the total PLFAs and bacterial PLFAs increased by 13.1% and 27.3%, respectively. However, the fungal PLFAs decreased significantly in warm-wet season in MP. The total activity of the cellulose-degrading enzyme β-glucosidase was significantly greater with mixed N2-fixing species in both dry-cool and wet-warm season. The increase in the Alk-C/O-Alk-C ratio and SOC was strongly associated with both C-acquisition activity and bacterial community.Conclusions
Our findings highlight the importance of N2-fixing species in regulating both soil microbial communities and their functioning in association with soil extracellular enzyme activities, which contribute to the increased soil carbon storage and recalcitrant carbon composition in Eucalyptus plantations.12.
13.
Aims
Despite extensive studies on effects of elevated CO2 concentration ([CO2]e) on plant growth, few studies have investigated the responses of native grassland plant species to [CO2]e in terms of nutrient acquisition.Methods
The effects of [CO2]e (769 ± 23 ppm) on Artemisia frigida and Stipa krylovii, two dominant species in Inner Mongolia steppe were investigated by growing them for 7 weeks in Open-Top Chambers (OTC).Results
Exposure to [CO2]e enhanced shoot and root growth of A. frigida and S. krylovii. Elevated [CO2] increased photosynthetic rates (Pn) by 34 % in A. frigida but decreased Pn by 52 % in S. krylovii. Moreover, root-secreted acid phosphatase activity in A. frigida was stimulated by [CO2]e, while exudation of malate from roots of S. krylovii was suppressed by [CO2]e. Exposure to [CO2]e led to a decrease in P concentration in shoots and roots of A. frigida and S. krylovii, but total amount of P accumulated in shoots and roots of both species was increased by [CO2]e.Conclusions
The two dominant species in temperate steppes differed in their responses to [CO2]e, such that A. frigida was more adapted to [CO2]e than S. krylovii under low availability of soil P.14.
15.
Young-Saeng Kim Il-Sup Kim Joseph S. Boyd Arnaud Taton James W. Golden Ho-Sung Yoon 《Biotechnology letters》2017,39(10):1499-1507
Objectives
To improve the oxidative stress tolerance, biomass yield, and ascorbate/dehydroascorbate (AsA/DHA) ratio of Synechococcus elongatus PCC 7942 in the presence of H2O2, by heterologous expression of the dehydroascorbate reductase (DHAR) gene from Brassica juncea (BrDHAR).Results
Under H2O2 stress, overexpression of BrDHAR in the transgenic strain (BrD) of S. elongatus greatly increased the AsA/DHA ratio. As part of the AsA recycling system, the oxidative stress response induced by reactive oxygen species was enhanced, and intracellular H2O2 level decreased. In addition, under H2O2 stress conditions, the BrD strain displayed increased growth rate and biomass, as well as higher chlorophyll content and deeper pigmentation than did wild-type and control strains.Conclusion
By maintaining the AsA pool and redox homeostasis, the heterologous expression of BrDHAR increased S. elongatus tolerance to H2O2 stress, improving the biomass yield under these conditions. The results suggest that the BrD strain of S. elongatus, with its ability to attenuate the deleterious effects of ROS caused by environmental stressors, could be a promising platform for the generation of biofuels and other valuable bioproducts.16.
Background
Stress urinary incontinence (SUI) is a relatively common disorder that significantly affects the quality of life. Many conservative and surgical treatment methods have been recommended for SUI, but they have major limitations.Aims
To assess the use of the CO2 fractional laser in the treatment of SUI.Methods
This clinical trial included 55 patients with confirmed SUI. Patients underwent fractional CO2 laser treatment 3 times at 30-day intervals. Data on age, smoking history, sexual activity, menopause, and history of hormone replacement therapy (HRT) were collected. Response to treatment was assessed by SUI severity and the level of sexual satisfaction was assessed using the visual analog scale (VAS). Patients were evaluated at 3 different time points: before treatment, and 45 days and 6 months after the last laser treatment.Results
The mean patient age was 44.4±11.4 years (range: 28 to 68 years). Smoking history was positive in 6 patients (9.1%); 19 (54.3%) were menopausal on HRT. The SUI severity score at baseline (before treatment) was 8.56±0.62 and decreased to 2.28 6 months after treatment (p<0.0001). The sexual satisfaction score was 3±0.94 at baseline and increased to 7.87±0.93 6 months after treatment (day 180) (p<0.0001, slope = + 2.2)Conclusion
Our findings are in line with a previous study that showed the value of transvaginal CO2 fractional laser treatment for alleviation of SUI symptoms and its potential as an alternative treatment. We also observed improved sexual satisfaction in SUI patients.17.
Manuela?Gorgel Jakob?Jensen?Ulstrup Andreas?B?ggild Nykola?C?Jones S?ren?V?Hoffmann Poul?Nissen Thomas?Boesen
Background
Type IV pili are widely expressed among Gram-negative bacteria, where they are involved in biofilm formation, serve in the transfer of DNA, motility and in the bacterial attachment to various surfaces. Type IV pili in Shewanella oneidensis are also supposed to play an important role in extracellular electron transfer by the attachment to sediments containing electron acceptors and potentially forming conductive nanowires.Results
The potential nanowire type IV pilin PilBac1 from S. oneidensis was characterized by a combination of complementary structural methods and the atomic structure was determined at a resolution of 1.67 Å by X-ray crystallography. PilBac1 consists of one long N-terminal α-helix packed against four antiparallel β-strands, thus revealing the core fold of type IV pilins. In the crystal, PilBac1 forms a parallel dimer with a sodium ion bound to one of the monomers. Interestingly, our PilBac1 crystal structure reveals two unusual features compared to other type IVa pilins: an unusual position of the disulfide bridge and a straight α-helical section, which usually exhibits a pronounced kink. This straight helix leads to a distinct packing in a filament model of PilBac1 based on an EM model of a Neisseria pilus.Conclusions
In this study we have described the first structure of a pilin from Shewanella oneidensis. The structure possesses features of the common type IV pilin core, but also exhibits significant variations in the α-helical part and the D-region.18.
Simone Vassiliadis Kim M. Plummer Kevin S. Powell Simone J. Rochfort 《Metabolomics : Official journal of the Metabolomic Society》2018,14(10):133
Introduction
The aphid Rhopalosiphum padi L. is a vector of Barley yellow dwarf virus (BYDV) in wheat and other economically important cereal crops. Increased atmospheric CO2 has been shown to alter plant growth and metabolism, enhancing BYDV disease in wheat. However, the biochemical influences on aphid metabolism are not known.Objectives
This work aims to determine whether altered host-plant quality, influenced by virus infection and elevated CO2, impacts aphid weight and metabolism.Methods
Untargeted 1H NMR metabolomics coupled with multivariate statistics were employed to profile the metabolism of R. padi reared on virus-infected and non-infected (sham-inoculated) wheat grown under ambient CO2 (aCO2, 400 µmol mol?1) and future, predicted elevated CO2 (eCO2, 650 µmol mol?1) concentrations. Un-colonised wheat was also profiled to observe changes to host-plant quality (i.e., amino acids and sugars).Results
The direct impacts of virus or eCO2 were compared. Virus presence increased aphid weight under aCO2 but decreased weight under eCO2; whilst eCO2 increased non-viruliferous (sham) aphid weight but decreased viruliferous aphid weight. Discriminatory metabolites due to eCO2 were succinate and sucrose (in sham wheat), glucose, choline and betaine (in infected wheat), and threonine, lactate, alanine, GABA, glutamine, glutamate and asparagine (in aphids), irrespective of virus presence. Discriminatory metabolites due to virus presence were alanine, GABA, succinate and betaine (in wheat) and threonine and lactate (in aphids), irrespective of CO2 treatment.Conclusion
This study confirms that virus and eCO2 alter host-plant quality, and these differences are reflected by aphid weight and metabolism.19.
Nicholas J. Bond Albert Koulman Julian L. Griffin Zoe Hall 《Metabolomics : Official journal of the Metabolomic Society》2017,13(11):128
Introduction
Mass spectrometry imaging (MSI) experiments result in complex multi-dimensional datasets, which require specialist data analysis tools.Objectives
We have developed massPix—an R package for analysing and interpreting data from MSI of lipids in tissue.Methods
massPix produces single ion images, performs multivariate statistics and provides putative lipid annotations based on accurate mass matching against generated lipid libraries.Results
Classification of tissue regions with high spectral similarly can be carried out by principal components analysis (PCA) or k-means clustering.Conclusion
massPix is an open-source tool for the analysis and statistical interpretation of MSI data, and is particularly useful for lipidomics applications.20.