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Fatty acid hydratase for value-added biotransformation:A review

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Chinese Journal of Chemical Engineering 2020年第8期28卷 2051-2063页

作者： Yan Zhang Bekir Engin Eser Peter kristensen Zheng Guo Department of Engineering Faculty of Science and TechnologyAarhus UniversityGustav wieds vej 108000 AarhusDenmark Faculty of Engineering and Science Department of Chemistry and BioscienceAalborg University9220 AalborgDenmark

The synthesis of hydroxy fatty acids(HFAs) from renewable oil feedstock by addition of water onto C_C bonds has attracted great attention in recent years. Given that selective asymmetric hydration of non-activated C_C bonds has been proven difficult to achieve with chemical catalysts, enzymatic catalysis by fatty acid hydratases(FAHs) presents an attractive alternative approach to produce value-added HFAs with high regio-, enantioand stereospecificity, as well as excellent atom economy. Even though FAHs have just been investigated as a potential biocatalyst for a decade, remarkable information about FAHs in different aspects is available;however, a comprehensive review has not been archived. Herein, we summarize the research progresses on biochemical characterization, structural and mechanistic determination, enzyme engineering, as well as biotechnological application of FAHs. The current challenges and opportunities for an efficient utilization of FAHs in organic synthesis and industrial applications are critically discussed.

关键词： Hydroxy fatty acids Fatty acid hydratases Enzyme characterization Catalytic mechanism Enzyme engineering Biotransformation

Using coloured roots to study root interaction and competition in intercropped legumes and non-legumes

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Journal of Plant Ecology 2010年第3期3卷 191-199页

作者： Giacomo Tosti Kristian Thorup-kristensen Department of Agriculture and Environmental Sciences University of PerugiaBorgo XX Giugno 7406121 PerugiaItaly Department of Agriculture and Ecology Faculty of Life SciencesUniversity of CopenhagenHøjbakkegaards Alle 13DK-2630 TaastrupDenmark

Aims Root interactions between neighbour plants represent a fundamental aspect of the competitive dynamics in pure stand and mixed cropping *** comprehension of such phenomena places big methodological challenges,and still needs *** objectives of this work were(i)to test if a species with coloured roots can be used to examine the interaction in a legume-non-legume intercropping system;(ii)to verify the importance of initial root growth on the successive root development ofmixture component plants;(iii)to test if the root interaction in the shallowlayers has consequences for deep root growth and(iv)to compare the effect of intraspecific and interspecific competition on root development and biomass *** A detailed study on root growth and interaction was carried out using rhizotron tubes where two legume species were grown in pure stands or were intercropped with red beet,a variety of Beta vulgaris *** clear red *** the rhizotrons,the three species were grown either without competitors,with two plants of the same species to measure intraspecific competition or with one legume and one red beet plant to study interspecific *** use of mixtures where one component has clearly coloured roots,together with several scalar measurements of root depth and proliferation,allowed the measurement of the root system of each species when grown in the *** findings The use of rhizotron tubes coupled with species with coloured roots represented a valuable method to study the belowground interaction in mixed cropping *** initial root growth was a very important feature for the subsequent dominance of a species and it was not related to seed *** root growth was also important because the root interactions in the shallower soil layers were found to influence the root growth in deeper *** root system of the red beet showed much faster and deeper growth than that of the legumes,and made red beet

关键词： red beet root competition root interaction root proliferation rhizotron

High frame rate multi-resonance imaging refractometry with distributed feedback dye laser sensor

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Light(Science & Applications) 2015年第1期4卷 410-414页

作者： Christoph Vannahme Martin Dufva Anders kristensen Technical University of Denmark Department of Micro-and NanotechnologyDTU NanotechDK-2800 Kgs.LyngbyDenmark

High frame rate and highly sensitive imaging of refractive index changes on a surface is very promising for studying the dynamics of dissolution,mixing and biological processes without the need for ***,a highly sensitive distributed feedback(DFB)dye laser sensor for high frame rate imaging refractometry without moving parts is *** dye lasers are low-cost and highly sensitive refractive index *** unique multi-wavelength DFB laser structure presented here comprises several areas with different grating *** two dimensions of space is enabled by analyzinglaser light from all areasin parallelwith an imaging *** this multi-resonance imaging refractometry method,the spatial position in one direction is identified from the horizontal,i.e.,spectral position of the multiple laser lines which is obtained from the spectrometer charged coupled device(CCD)*** orthogonal spatial position is obtained from the vertical spatial position on the spectrometer CCD array as in established spatially resolved ***,the imaging technique is demonstrated by monitoring the motion of small sucrose molecules upon dissolution of solid sucrose in *** omission of moving parts improves the robustness of the imaging system and allows a very high frame rate of up to 12 Hz.

关键词： distributed feedback laser label-free imaging laser sensor refractive index sensor

Removal of chromophoric dissolved organic matter under combined photochemical and microbial degradation as a response to different irradiation intensities

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Journal of Environmental Sciences 2022年第8期34卷 76-86页

作者： Theis Kragh Kaj Sand-Jensen Emil kristensen Ole Pedersen Mikkel Madsen-Фterbye Department of Biology University of Southern DenmarkSyddanmark 5230Denmark Freshwater Biological Laboratory Department of BiologyUniversity of CopenhagenCopenhagen 2100Denmark

Throughout the freshwater continuum, Dissolved Organic Carbon(DOC) and the colored fraction, Chromophoric Dissolved Organic Material(CDOM), are continuously being added,removed, and transformed, resulting in changes in the chromophoricity and lability of organic matter over time. We examined, experimentally, the effect of increasing irradiationintensities on the combined photochemical and microbial degradation of CDOM and *** was done by using a simulated mixed water column: aged water from a humic lake was exposed to four irradiation-intensities – representing winter, early and late spring, and summer conditions(0.10, 0.16, 0.36, and 0.58 W/m^(2)) – and compared with dark controls over 37days. We found a linear relationship between CDOM degradation and irradiation-intensities up to 0.36 W/m^(2);the degradation rate saturated at higher intensities, both at specific wavelengths and for broader intervals. After 37 days at high irradiation-intensity, CDOM absorption of irradiation at 340 nm had been reduced by 41%;48% of DOC had been removed and DOC degradation continued to increase. Aromaticity(SUVA254) declined significantly over 37 days at the two lowest but not at the two highest UV-intensities;levels in unexposed control water remained constant. Direct observations of the humic lake showed that CDOM absorption of irradiation(340 nm) declined by 27% from winter to summer. A model based on hydrological CDOM input and CDOM degradation calculated from field measurements of UV-radiation and experimental CDOM degradation with UV-exposure from sunlight accurately predicted the annual course as observed in the lake. With no external CDOM input,92% of the CDOM could be degraded in a year. The results support the notion that combined photochemical and microbial CDOM degradation can be remarkably higher in lakes than previously thought and that humic lakes retain their color due to light absorption by ongoing CDOM input.

关键词： Biodegradation Brownification Carbon cycling CDOM DOC Humic lake Photobleaching UV-bleaching

Feasibility of progressive strength training shortly after hip fracture surgery

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World Journal of Orthopedics 2013年第4期4卷 248-258页

作者： Jan Overgaard Morten T kristensen Department of Rehabilitation Municipality of Lolland Physical Medicine and Rehabilitation Research-Copen-hagen (PMR-C)DK-4930 Maribo Denmark Physical Medicine and Rehabilitation Research-Copenhagen (PMR-C) Departments of Physiotherapy and Orthopaedic Surgery Copenhagen University Hospital HvidovreDK-2650 Hvidovre Denmark

AIM: To investigate the feasibility of a 6-wk progressive strength-training programme commenced shortly after hip fracture surgery in community-dwelling ***: This prospective, single-blinded cohort study evaluated 31 community-dwelling patients from four outpatient geriatric health centres aged 60 years or older, who started a 6-wk programme at a mean of 17.5 ± 5.7 d after hip fracture surgery. The intervention consisted primarily of progressive fractured kneeextension and bilateral leg press strength training(twice weekly), with relative loads commencing at 15 and increasing to 10 repetitions maximum(RM), with three sets in each session. The main measurements included progression in weight loads, hip fracture-related pain during training, maximal isometric knee-extension strength, new mobility score, the timed up and go test, the 6-min walk test and the 10-meter fast speed walk test, assessed before and after the ***: Weight loads in kilograms in the fractured limb knee-extension strength training increased from 3.3 ± 1.5 to 5.7 ± 1.7 and from 6.8 ± 2.4 to 7.7 ± 2.6, respectively, in the first and last 2 wk(P < 0.001). Correspondingly, the weight loads increased from 50.3 ± 1.9 to 90.8 ± 40 kg and from 108.9 ± 47.7 to 121.9 ± 54 kg in the bilateral leg press exercise(P < 0.001). Hip fracture-related pain was reduced, and large improvements were observed in the functional outcome measurements, e.g., the 6-min walk test improved from 200.6 ± 79.5 to 322.8 ± 68.5 m(P < 0.001). The fractured limb knee-extension strength deficit was reduced from 40% to 17%, compared with the non-fractured limb. Ten patients reported knee pain as a minor restricting factor during the last 10 RM knee-extension strength-training sessions, but with no significant influences on performance. CONCLUSION: Progressive strength training, initiated shortly after hip fracture surgery, seems feasible and does not increase hip fracture-related pain. Progressive strength tra

关键词： Hip fracture Resistance training Feasibility Repetition maximum Pain

Net absorption and liver metabolism of amino acids and heat production of portaldrained viscera and liver in multiparous sows during transition and lactation

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Journal of Animal Science and Biotechnology 2020年第2期11卷 424-439页

作者： Liang Hu Niels Bastian kristensen Lianqiang Che De Wu Peter Kappel Theil Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education Institute of Animal NutritionSichuan Agricultural UniversityNo.211Huimin RoadWenjiang DistrictChengduSichuan 611130People’s Republic of China Department of Animal Science Faculty of Science and TechnologyAarhus UniversityDK-8830 TjeleDenmark Present address:SEGES Danish Pig Research Centre DK-1609 CopenhagenDenmark

Background:Determination of nutrient requirements in the late gestating and lactating sows is essential to optimize sow *** objectives of the present study were to quantify amino acid(AA)fluxes and heat production across portal-drained viscera(PDV)and liver in multiparous sows during transition and ***:Eight second parity sows were fitted with indwelling catheters in the femoral artery and in the mesenteric,portal and hepatic *** hourly sets of blood samples were taken starting 0.5 h before feeding at−10,−3,+3,and+17 d in milk(DIM).Blood gases,plasma metabolites and apparent total tract digestibility(ATTD)of nutrients were ***:Feed intake,the ATTD of DM,energy,nitrogen,fat and crude fiber changed with DIM(P<0.001).Except for Glu,O2,and urea,all net portal fluxes were positive,and all were affected by DIM(P<0.05)and by sampling time(P<0.01).Compared with pre partum levels,net portal uptake of AA was 3-63%lower at+3 DIM but 40-100%higher at+17 *** portal fluxes of AA peaked at 1.5 to 2.5 h after feeding except for Glu,and they were positively correlated with changes in sow feed intake across *** net portal recovery was low for Met(49%),Thr(54%),and His(54%)and high for the remaining essential AA(63-69%)and none of them differed across *** hepatic uptake(*** oxidation)of Lys,Thr,Ile,Leu and Phe peaked at 0.5 to 2.5 h after feeding,whereas uptake of Trp,Val,and His was constant,while that of Met was close to ***:The net portal recovery was substantially lower for Met,Thr,and His than the remaining essential *** AA oxidation peaks 0.5 to 2.5 h after *** heat production in PDV and liver was approximately two-fold higher at peak lactation compared to other *** study suggests that lysine was the limiting AA in peak lactation but not in early lactation.

关键词： Gestation Heat production Lactation Net hepatic flux Net portal flux Sow

From preference to landscape sustainability:a bibliometric review of landscape preference research from 1968 to 2019

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Ecosystem Health and Sustainability 2021年第1期7卷 271-288页

作者： Gaoyuan Yang Zhaowu Yu Jinguang Zhang Lone Søderkvist kristensen Department of Geosciences and Natural Resource Management Faculty of ScienceUniversity of CopenhagenCopenhagenDenmark Department of Environmental Science and Engineering Fudan UniversityShanghaiChina College of Landscape Architecture Nanjing Forestry UniversityNanjingChina

Landscape preference(LP)studies highlight one of the most important issues of human-environment relationship,and their related publications have increased rapidly over the last two ***,there is no systematic review with a holistic understanding of this *** we applied a bibliometric approach to examine the evolution of LP research and identify its status and future *** obtained 7,637 LP research publications from Web of Science core collection from 1968 to 2019 and analyzed the characteristics of publication outputs as well as performances in various countries and ***,content keywords analysis was conducted to discover the drivers,focus,motivation,and trends of LP *** found that 1)publications,subject categories,and active journals increased rapidly since the 2000s;2)the USA,England,and Australia are the leading countries in LP research,while China is starting to have some influence;3)LP research is most closely linked to ecological and environmental studies,being developed by objective drivers,i.e.,interactions with landscape change,and subjective motivations;and 4)LP research is advancing the landscape sustainability science,integrating natural and social science together through ecosystem *** comprehensively reviewing the evolution and prospect of LP research,we provide insights for further research in this field.

关键词： Landscape preference scientific literature bibliometric analysis trends and prospects landscape sustainability

A Cambrian micro-lobopodian and the evolution of arthropod locomotion and reproduction

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Chinese Science Bulletin 2007年第24期52卷 3385-3392页

作者： Andreas Maas Georg Mayer Reinhardt M. kristensen Dieter Waloszek Section for Biosystematic Documentation University of Ulm Helmholtzstrasse 20 D-89081 Ulm Germany Department of Anatomy and Cell Biology University of Melbourne Victoria Australia 3010 Zoological Museum University of Copenhagen 15 Universitetsparken DK-2100 Copenhagen Denmark

The evolutionary success of arthropods, the most abundant and diverse animal group, is mainly based on their segmented body and jointed appendages, features that had evolved most likely already before the Cambrian. The first arthropod-like animals, the lobopodians from the Early Cambrian, were unsclerotized and worm-like, and they had unjointed tubular legs. Here we describe the first three-dimensionally preserved Cambrian lobopodian. The material presented of Orstenotubulus evamuellerae gen. et sp. nov. is the smallest and youngest of a lobopodian known. O. evamuellerae shows strikingly detailed similarities to Recent tardigrades and/or onychophorans in its cellular-structured cuticle and the telescopic spines. It also shows similarities to other, longer known lobopodians, but which are ten times as large as the new form. These similarities include the finely annulated body and legs, which is characteristic also for Recent onychophorans, and paired humps continuing into spines situated dorsally to the leg insertions, a feature lacking in the extant forms. The morphology of O. evamuellerae not only elucidates our knowledge about lobopodians, but also aids in a clearer picture of the early evolution of arthropods. An example is the single ventral gonopore between a limb pair of O. evamuellerae, which indicates that a single gonopore, as developed in onychophorans, tardigrades, pentastomids, myriapods and insects, might represent the plesiomorphic state for Arthropoda, while the paired state in chelicerates and crustaceans was convergently achieved. Concerning life habits, the lateral orientation of the limbs and their anchoring spines of the new lobopodian imply that early arthropods were crawlers rather than walkers.

关键词：寒武纪节足动物门进化发展史生殖系统移动力

Size-asymmetric root competition in deep,nutrient-poor soil

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Journal of Plant Ecology 2019年第1期12卷 78-88页

作者： Camilla Ruø Rasmussen Anne Nygaard Weisbach Kristian Thorup-kristensen Jacob Weiner Department of Plant and Environmental Sciences University of CopenhagenHøjbakkegaard Allé13Taastrup DK-2630Denmark Department of Plant and Environmental Sciences University of CopenhagenThorvaldsensvej 40Frederiksberg DK-1871Denmark

Aims There is much evidence that plant competition below ground is size symmetric,*** competing plants share contested resources in proportion to their *** researchers have hypothesized that a patchy distribution of soil nutrients could result in size-asymmetric root *** tested this *** In a greenhouse experiment,Triticum aestivum(wheat)individ-uals of different initial sizes were grown alone or with below-ground competition from one neighbour,in 1 m tall,narrow containers in a nitrogen-poor field soil with(i)no added nitro-gen,(ii)nitrogen fertilizer mixed into the upper 50 cm,and(iii)the same amount of fertilizer mixed into a 20-30 cm deep *** measured total leaf length throughout the experiment,and above-ground biomass and nitrogen concentration at *** also measured root depth and frequency over time in a subset of *** Findings Competing plants were half the size of non-competing plants,meaning that root competition was very *** competition was size-asym-metric to some degree in all soil *** larger than the target plant showed a greater per-unit-size effect on target growth than neighbours smaller than the *** variation increased over time for competing individuals,but decreased for non-competing *** to expectations,the presence of a high-nutrient patch reduced the strength and size asymmetry of competition *** asym-metry in poor,deep soils may result from directionality in resource interception as roots compete for limited nutrients by growing deeper into soil layers that have not yet been *** competition can be size asymmetric,but not to the same degree as competition for light.

关键词： below-ground competition resource pre-emption size inequality size advantage Triticum aestivum