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1.
Amy Yi Hsan Saik Yau Yan Lim Johnson Stanslas Wee Sim Choo 《Biotechnology letters》2017,39(2):297-304
Objectives
To investigate the lipase-catalyzed acylation of quercetin with oleic acid using Candida antarctica lipase B.Results
Three acylated analogues were produced: quercetin 4′-oleate (C33H42O8), quercetin 3′,4′-dioleate (C51H74O9) and quercetin 7,3′,4′-trioleate (C69H106O10). Their identities were confirmed with UPLC–ESI–MS and 1H NMR analyses. The effects of temperature, duration and molar ratio of substrates on the bioconversion yields varied across conditions. The regioselectivity of the acylated quercetin analogues was affected by the molar ratio of substrates. TLC showed the acylated analogues had higher lipophilicity (152% increase) compared to quercetin. Partition coefficient (log P) of quercetin 4′-oleate was higher than those of quercetin and oleic acid. Quercetin 4′-oleate was also stable over 28 days of storage.Conclusions
Quercetin oleate esters with enhanced lipophilicity can be produced via lipase-catalyzed reaction using C. antarctica lipase B to be used in topical applications.2.
Takuya Sugawara Mariko Chinzei Setsuko Numano Chifumi Kitazaki Munehiko Asayama 《Biotechnology letters》2018,40(5):829-836
Objective
A novel filamentous cyanobacterium, a photosynthesizing microorganism, was isolated from a river, and its unique features of flocculation and pentadecane production were characterized.Results
Microscopic observations and a phylogenetic analysis with 16S rDNA revealed that this strain was a Limnothrix species denoted as the SK1-2-1 strain. Auto cell-flocculation was observed when this strain was exposed to a two-step incubation involving a standing cultivation following a shaking preincubation. Flocculation was enhanced by blue light at a wavelength at 470 nm and irradiation for several hours to 1 day. Moreover, the strain exhibiting exponential cell growth may preferentially accumulate alkanes as pentadecane C15H32 alkane, which may be used as jet fuel, at a range of approximately 1% in the dry cell weight of flocculated cells.Conclusion
This is the first study on biofuel production using flocculated cells in which the specific manner of production may be regulated by cultivation conditions.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.
Asrin Rahimi Iraj Amiri Amaneh Mohammadi Roushandeh Zoleikha Golipour Choshali Zohreh Alizadeh Tayebeh Artimani Saeid Afshar Sara Soleimani Asl 《Biotechnology letters》2018,40(3):609-615
Objective
To investigate the effect of H2O2 on the migration and antioxidant defense of mesenchymal stem cells (MSCs) and the neurotrophic effects of H2O2-treated MSCs on spinal cord injury (SCI).Results
Sublethal concentrations of H2O2 decreased cell migration and expression of CXCR4 and CCR2 as well as Nrf2 expression in MSCs. In the second phase, transplantation of treated and untreated MSCs to SCI caused minor changes in locomotor dysfunction. There was a significantly difference between cell-treated and spinal cord injury groups in expression of BDNF (brain-derived neurotrophic factor). Transplantation of H2O2-treated cells caused an increase in BDNF expression compared to non-treated cells.Conclusion
Transplantation of H2O2-treated stem cells may have protective effects against SCI through by increasing neurotrophic factors.5.
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.6.
7.
Objective
Palladised cells of Desulfovibrio desulfuricans and Shewanella oneidensis have been reported as fuel cell electrocatalysts but growth at scale may be unattractive/costly; we have evaluated the potential of using E. coli, using H2/formate for Pd-nanoparticle manufacture.Results
Using ‘bio-Pd’ made under H2 (20 wt%) cyclic voltammograms suggested electrochemical activity of bio-NPs in a native state, attributed to proton adsorption/desorption. Bio-Pd prepared using formate as the electron donor gave smaller, well separated NPs; this material showed no electrochemical properties, and hence little potential for fuel cell use using a simple preparation technique. Bio-Pd on S. oneidensis gave similar results to those obtained using E. coli.Conclusion
Bio-Pd is sufficiently conductive to make an E. coli-derived electrochemically active material on intact, unprocessed bacterial cells if prepared at the expense of H2, showing potential for fuel cell applications using a simple one-step preparation method.8.
Chunqiu He Wen Dong Jing Li Yanpeng Li Chao Huang Yanling Ma 《Biotechnology letters》2017,39(9):1381-1388
Objectives
To improve rhamnolipid production and its potential application in removal of crude oil, the recombinant Pseudomonas aeruginosa strain DAB was constructed to enhance yield of rhamnolipids.Results
Strain DAB had a higher yield of 17.3 g rhamnolipids l?1 in the removal process with crude oil as the sole carbon source than 10 g rhamnolipids l?1 of wild-type strain DN1, where 1% crude oil was degraded more than 95% after 14 days cultivation. These rhamnolipids reduced the surface tension of water from 72.92 to 26.15 mN m?1 with CMC of 90 mg l?1. The predominant rhamnolipid congeners were Rha–C10–C10 and Rha–Rha–C10–C10 detected by MALDI-TOF MS analysis with approx. 70% relative abundance, although a total of 21 rhamnolipid congeners were accumulated.Conclusion
Increasing the copy number of rhlAB genes efficiently enhanced the production of rhamnolipids by the recombinant P. aeruginosa DAB and thus presents a promising application for the bioremediation process.9.
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.10.
11.
Cédric Gonneau Sanjay K. Mohanty Lee H. Dietterich Wei-Ting Hwang Jane K. Willenbring Brenda B. Casper 《Plant and Soil》2017,416(1-2):149-163
Background and aims
Elemental uptake in serpentine floras in eastern North America is largely unknown. The objective of this study was to determine major and trace element concentrations in soil and leaves of three native pseudo-metallophyte C4 grasses in situ at five sites with three very different soil types, including three serpentine sites, in eastern USA.Methods
Pseudo-total and extractible concentrations of 15 elements were measured and correlated from the soils and leaves of three species at the five sites.Results
Element concentrations in soils of pseudo-metallophytes varied up to five orders of magnitude. Soils from metalliferous sites exhibited higher concentrations of their characteristic elements than non-metalliferous. In metallicolous populations, elemental concentrations depended on the element. Concentrations of major elements (Ca, Mg, K) in leaves were lower than typical toxicity thresholds, whereas concentrations of Zn were higher.Conclusions
In grasses, species can maintain relatively low metal concentrations in their leaves even when soil concentrations are richer. However, in highly Zn-contaminated soil, we found evidence of a threshold concentration above which Zn uptake increases drastically. Finally, absence of main characteristics of serpentine soil at one site indicated the importance of soil survey and restoration to maintain serpentinophytes communities and avoid soil encroachment.12.
Xiaojie Duan Mingming Zheng Yu Liu Zhengqiang Jiang Shaoqing Yang 《Biotechnology letters》2016,38(12):2127-2135
Objectives
To identify novel cold-active lipases from fungal sources and improve their production by heterologous expression in Pichia pastoris.Results
A novel cold-active lipase gene (ReLipB) from Rhizomucor endophyticus was cloned. ReLipB was expressed at a high level in Pichia pastoris using high cell-density fermentation in a 5-l fermentor with the highest lipase activity of 1395 U/ml. The recombinant lipase (RelipB) was purified and biochemically characterized. ReLipB was most active at pH 7.5 and 25 °C. It was stable from pH 4.5–9.0. It exhibited broad substrate specificity towards p-nitrophenyl (pNP) esters (C2–C16) and triacylglycerols (C2–C12), showing the highest specific activities towards pNP laurate (231 U/mg) and tricaprylin (1840 U/mg), respectively. In addition, the enzyme displayed excellent stability with high concentrations of organic solvents including cyclohexane, n-hexane, n-heptane, isooctane and petroleum ester and surfactants.Conclusions
A novel cold-active lipase from Rhizomucor endophyticus was identified, expressed at a high level and biochemically characterized. The high yield and unique enzymatic properties make this lipase of some potential for industrial applications.13.
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.14.
Weiming Sun Jinxia Yang Yuanzhou Zhang Yuxin Xi Xin Wen Di Yuan Yuehong Wang Can Wei Rui Wang Lingyun Wu Hongzhu Li Changqing Xu 《Cell & Bioscience》2017,7(1):67
Background
A gasotransmitter hydrogen sulfide (H2S) plays an important physiological and pathological role in cardiovascular system. Ischemic post-conditioning (PC) provides cardioprotection in the young hearts but not in the aged hearts. Exogenous H2S restores PC-induced cardioprotection by inhibition of mitochondrial permeability transition pore opening and oxidative stress and increase of autophagy in the aged hearts. However, whether H2S contributes to the recovery of PC-induced cardioprotection via down-regulation of endoplasmic reticulum stress (ERS) in the aged hearts is unclear.Methods
The aged H9C2 cells (the cardiomyocytes line) were induced using H2O2 and were exposed to H/R and PC protocols. Cell viability was observed by CCK-8 kit. Apoptosis was detected by Hoechst 33342 staining and flow cytometry. Related protein expressions were detected through Western blot.Results
In the present study, we found that 30 μM H2O2 induced H9C2 cells senescence but not apoptosis. Supplementation of NaHS protected against H/R-induced apoptosis, the expression of cleaved caspase-3 and cleaved caspase-9 and the release of cytochrome c. The addition of NaHS also counteracted the reduction of cell viability caused by H/R and decreased the expression of GRP 78, CHOP, cleaved caspase-12, ATF 4, ATF 6 and XBP-1 and the phosphorylation of PERK, eIF 2α and IRE 1α. Additionally, NaHS increased Bcl-2 expression. PC alone did not provide cardioprotection in H/R-treated aged cardiomyocytes, which was significantly restored by the supplementation of NaHS. The beneficial role of NaHS was similar to the supply of 4-PBA (an inhibitor of ERS), GSK2656157 (an inhibitor of PERK), STF083010 (an inhibitor of IRE 1α), respectively, during PC.Conclusion
Our results suggest that the recovery of myocardial protection from PC by exogenous H2S is associated with the inhibition of ERS via down-regulating PERK-eIF 2α-ATF 4, IRE 1α-XBP-1 and ATF 6 pathways in the aged cardiomyocytes.15.
Jonathan M. Wagner Sum Chan Timothy J. Evans Sara Kahng Jennifer Kim Mark A. Arbing David Eisenberg Konstantin V. Korotkov 《BMC structural biology》2016,16(1):5
Background
The ESX-1 type VII secretion system is an important determinant of virulence in pathogenic mycobacteria, including Mycobacterium tuberculosis. This complicated molecular machine secretes folded proteins through the mycobacterial cell envelope to subvert the host immune response. Despite its important role in disease very little is known about the molecular architecture of the ESX-1 secretion system.Results
This study characterizes the structures of the soluble domains of two conserved core ESX-1 components – EccB1 and EccD1. The periplasmic domain of EccB1 consists of 4 repeat domains and a central domain, which together form a quasi 2-fold symmetrical structure. The repeat domains of EccB1 are structurally similar to a known peptidoglycan binding protein suggesting a role in anchoring the ESX-1 system within the periplasmic space. The cytoplasmic domain of EccD1has a ubiquitin-like fold and forms a dimer with a negatively charged groove.Conclusions
These structures represent a major step towards resolving the molecular architecture of the entire ESX-1 assembly and may contribute to ESX-1 targeted tuberculosis intervention strategies.16.
17.
18.
Chenchen Zhang Jingyu Lu Duo Yang Xia Chen Yujun Huang Ruixia Gu 《Biotechnology letters》2018,40(4):729-735
Objective
To investigate the aerotolerance of Lactobacillus rhamnosus hsryfm 1301 and its influencing factors.Results
The growth rate of L. rhamnosus hsryfm 1301 weakened noticeably when the concentration of supplemented H2O2 reached 1 mM, and only 2% of all L. rhamnosus hsryfm 1301 cells survived in MRS broth supplemented with 2 mM H2O2 for 1 h. After pretreatment with 0.5 mM H2O2, the surviving cells of L. rhamnosus hsryfm 1301 in the presence of 5 mM H2O2 for 1 h increased from 3.7 to 7.8 log CFU. Acid stress, osmotic stress, and heat stress at 46 °C also enhanced its aerotolerance, while heat stress at 50 °C reduced the tolerance of L. rhamnosus hsryfm 1301 to oxidative stress. Moreover, treatment with 0.5 mM H2O2 increased the heat stress tolerance of L. rhamnosus hsryfm 1301 by approximately 150-fold.Conclusions
Lactobacillus rhamnosus hsryfm 1301 possesses a stress-inducible defense system against oxidative stress, and the cross-adaptation to different stresses is a promising target to increase the stress tolerance of L. rhamnosus hsryfm 1301 during probiotic food and starter culture production.19.
Introduction
Root-mediated changes in soil organic matter (SOM) decomposition, termed rhizosphere priming effects (RPE), play crucial roles in the global carbon (C) cycle, but their mechanisms and field relevance remain ambiguous. We hypothesize that nitrogen (N) shortages may intensify SOM decomposition in the rhizosphere because of increase of fine roots and rhizodeposition.Methods
RPE and their dependence on N-fertilization were studied using a C3-to-C4 vegetation change. N-fertilized and unfertilized soil cores, with and without maize, were incubated in the field for 50 days. Soil CO2 efflux was measured, partitioned for SOM- and root-derived CO2, and RPE was calculated. Plant biomass, microbial biomass C (MBC) and N (MBN), and enzyme activities (β-1,4-glucosidase; N-acetylglucosaminidase; L-leucine aminopeptidase) were analyzed.Results
Roots enhanced SOM mineralization by 35 % and 126 % with and without N, respectively. This was accompanied by higher specific root-derived CO2 in unfertilized soils. MBC, MBN and enzyme activities increased in planted soils, indicating microbial activation, causing positive RPE. N-fertilization had minor effects on MBC and MBN, but it reduced β-1,4-glucosidase and L-leucine aminopeptidase activities under maize through lower root-exudation. In contrast, N-acetylglucosaminidase activity increased with N-fertilization in planted and unplanted soils.Conclusions
This study showed the field relevance of RPE and confirmed that, despite higher root biomass, N availability reduces RPE by lowering root and microbial activity.20.