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American Journal of Plant Sciences 2023年第4期14卷 472-481页

作者： Nishat Tasnim Debabrata Karmakar Rakibul Hasan Rashadul Islam Saddam Hossain Aftab Ali Shaikh Rezaul Karim Bangladesh Council of Scientific and Industrial Research Dhanmondi (BCSIR) Dhaka Bangladesh Department of Chemistry University of Dhaka Dhaka Bangladesh

In this study, an effective environment for Chlorella vulgaris growth is sought after. As a substitute source of food and feed, increasing the cell density of Chlorella culture is one of the keys to ensuring sustainability. It can be showed from different studies that optimum light intensity and pH could increase cell density. In this study, the effects of light and pH on the growth rate of C. vulgaris were observed in photobioreactor. A specific wavelength (682 nm) was determined by UV-Vis Spectrophotometry to carry out the further analysis. The light intensities were set at 7409, 9261 and 11,113 lux;pH values were set at 7, 8 and 9 respectively. The experimental results depicted the light intensity of 9261 lux as the best due to the higher number of cells (48.56 × 106 cells/mL) obtained using this intensity. In terms of pH, without pH control, cell numbers were found to be highest under the light intensity of 9261 lux. When pH was controlled, it was found that under the optimum light intensity, pH control between 7.0 and 7.5 was the optimum range for the growth of C. vulgaris. Moreover, this method of study may possibly be a promising source of low cost culture for Chlorella vulgaris.

关键词： Chlorella vulgaris Light Intensity pH cell density

Changes in cell density and chlorophyll fluorescence with salinity in two Isochrysis galbana strains （Prymnesiophyceae）

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Changes in cell density and chlorophyll fluorescence with sa...

Consideration of transmembrane water exchange in pharmacokinetic model significantly improves the accuracy of DCE-MRI in estimating cellular density:A pilot study in glioblastoma multiforme

中国海洋湖沼学会藻类学分会第七届会员大会暨第十四次学术...

作者： Liang Ying Feng Lixia Tian Chuanyuan Yin Cuiling The Key Laboratory of Mariculture of Ministry of Education,Ocean University of China,Qingdao,266003,China

＜正＞Changes in the fluorescence parameters,cell density and relative chlorophyll content were investigated in the golden-brown algae Isochrysis galbana 3011 and（?）.galbana 8701,during exposure the cultures to different salinity（1-90 ppt）for different time（12h, 24h and 48h）,in order to indicate whether chlorophyll fluorescence could be used as a potential tool for salinity tolerance screening in microalgae.The results showed that

关键词： chlorophyll fluorescenne cell density Isochrysis galbana salinity

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Magnetic Resonance Letters 2022年第4期2卷 243-254页

作者： Zhenfeng Pang Zejun Wang Bao Wang Kaiyue Guo Cheng Meng Yingchao Liu Xueqian Kong Ruiliang Bai Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital School of MedicineZhejiang UniversityHangzhou310058China Center for Chemistry of High-Performance&Novel Materials Department of ChemistryZhejiang UniversityHangzhou310058China Interdisciplinary Institute of Neuroscience and Technology School of MedicineZhejiang UniversityHangzhou310058China Key Laboratory of Biomedical Engineering of Ministry of Education College of Biomedical Engineering and Instrument ScienceZhejiang UniversityHangzhou310058China Department of Radiology Qilu Hospital of Shandong UniversityJinan250012China Department of Neurosurgery Provincial Hospital Affiliated to Shandong First Medical UniversityJinan250021China Chemistry Instrumentation Center for Zhejiang University Hangzhou310058China MOE Frontier Science Center for Brain Science and Brain-machine Integration School of Brain Science and Brain MedicineZhejiang UniversityHangzhou310058China

Transmembrane water exchange(TWE)including transcytolemmal water exchange and transvascular water exchange is involved in many in vivo measurements and makes different contributions to the measuring results.In this study,we focus on the potential influence of TWE on the cell density parameter,intracellular water mole fraction pi,derived by dynamic contrast enhanced-magnetic resonance imaging(DCE-MRI)which has been reported as a technique to characterize perfusion and vascularization of tissues,but its accuracy in measuring cell density(or interstitial space)has been questioned.Sixteen patients with glioblastoma multiforme(GBM)were enrolled since GBM shows strong intratumor heterogeneity in both cell density and TWE.All the subjects were collected with DCE-MRI and apparent diffusion coefficient(ADC)map.The latter was considered as a valid surrogate of cell density.Extended Tofts(eTofts)model considering TWE as infinitely large variables and shutter-speed model(SSM)considering TWE as finite ones were used to fit DCE-MRI data.Monte Carlo(MC)and finite difference(FD)methods were used to simulate the influence of TWE on DCE-MRI-derived pi and ADC,respectively.The eTofts model shows a significant overestimation of pi in comparison with SSM in GBM(Pcellular water exchange rate constant(kio).Significant negative correlations between ADC and SSM-derived pi were found in both voxel-wise analyses(t-test P0.05)and a weaker inter-subject negative correlation(r=-0.56,P=0.02)were found between ADC and eTofts-derived pi.Further experimental and FD results revealed that kio made a limited contribution to ADC values in the physiological kio range in GBM,supporting ADC as a valid biomarker of cell density.These results suggest that the DCE-MRI pharmacokinetic shutter-speed model could significantly improve

关键词： DCE-MRI cell density Transcytolemmal water exchange Finite difference simulation Glioblastoma multiforme

Measuring the size and growth of single cells

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Biophysics Reports 2022年第3期8卷 150-157页

作者： An Gong Mingwei Min Guangzhou Laboratory Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences

The size and growth of a cell can be described by three related physical parameters: volume, density and mass. All the three are coupled to numerous biochemical reactions and biophysical properties of a cell. It is therefore not surprising that cell size and growth pattern are tightly regulated across all kingdoms of life. Indeed, deregulation of cell size and growth has been found to be associated with diseases.Yet, how cells regulate their size and how cell size connects to cell function remain poorly understood,partly due to the difficulties to precisely measure the size and growth of single cells. In this review, we summarize methods of measuring cell volume, density, and mass, and discuss how the new technologies may advance our understanding of cell size control.

关键词： cell volume cell mass cell size cell density

Influence and mechanism of N-(3-oxooxtanoyl)-L-homoserine lactone(C_8-oxo-HSL) on biofilm behaviors at early stage

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Journal of Environmental Sciences 2012年第12期24卷 2035-2040页

作者： Siqing Xia Lijie Zhou Zhiqiang Zhang Jixiang Li State Key Laboratory of Pollution Control and Resource Reuse Tongji UniversityShanghai 200092China Sustainable Technology Research Center Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China

N-acyl-homoserines quenching, enzymatic quenching of bacterial quorum sensing, has recently applied to mitigate biofilm in membrane bioreactor. However, the effect of AHLs on the behavior of biofilm formation is still sparse. In this study, Pseudomonas aeruginosa biofilm was formed on ultra-filtration membrane under a series of N-（3-0xooxtanoyl）-L-homoserine lactone （C8-0xo-HSL） concentrations. Diffusing Cs-oxo-HSL increased the growth rate of cells on biofilm where the concentration of Cs-oxo-HSL was over 10-7 g/L. The C8-0xo-HSL gradient had no observable influence on cell density and extracellular polymeric substances of biofilm with over 10-7 g/L Cs-oxo-HSL. Surprisingly, 10-11-10-8 g/L of Cs-Oxo-HSL had no effect on cell growth in liquid culture. The cell analysis demonstrated that the quorum sensing system might enhance the growth of neighboring cells in contact with surfaces into biofilm and may influence the structure and organization of biofilm.

关键词： quorum sensing C8-oxo-HSL biofilm formation ultra-filtration membrane cell density extracellular polymericsubstances

A survey of corneal changes caused by daily wear silicone hydrogel contact lenses

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Journal of Innovative Optical Health Sciences 2015年第6期8卷 92-100页

作者： Beata Kettesy Julianna Vardai Andras Berta Laszlo Modis Jr. Adam Kemeny-Beke Department of Ophthalmology University of Debrecen Nagyerdei krt.98. H-4032 DebrecenHungary

The examination of the effects of second generation lotra filcon B silicone hydrogel(SiH)lenses on the cornea when worn for three years of daily wear.Material and Methods:55 healthy patients were divided into two groups:current hydrogel contact lens wearers refitted with lotrafilcon B lenses(Group 1;28 patients)and neophyte contact lens wearers(Group 2;27 patients).Each patient's subjective eye comfort was measured with a self-administered questionnaire.The corneas were analyzed using contact specular microscope to measure corneal thickness and the endothelium before the SiH lenses werefitted after four weeks,one month,six months,one year,two years,and three years of lens wear.Results:Subjective complaints of patients in Group 1 were reduced;however patients in Group 2 experienced discomfort during the first two to four weeks of use.In Group 1,objective examinations identified a decrease in endothelial cell density.In Group 2,the endothelial cell density increased slightly in the first two years but decreased after three years.The results indicate that lotra filcon B slows down the deleterious effects of contact lenses.The coe±cient of variation significantly decreased after six months in Group 1(0.47 vs 0.44;p?0:049),whereas,in Group 2,the hexagonal cells improved significantly after one month(27.78 vs 28.25;p=0.025).Conclusion:Based on the subjects involved and the period of time under examination,it can be concluded that high-Dk SiH lenses support the physiological metabolism and functions of the cornea by improving oxygen provision.

关键词： Contact lens corneal endothelium silicone hydrogels specular microscopy cell density

Optimizing a nitrogen-supplemented, condensed corn soluble medium for growth of the Polyhydroxyalkanoate producer Pseudomonas putida KT217

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International Journal of Agricultural and Biological Engineering 2012年第4期5卷 62-67页

作者： Jeremy Javers William Gibbons Chinnadurai Karunanithy ICM Inc.ColwichKansasKSUSA Biology and Microbiology Department South Dakota State UniversityBrookings SD57007 USA Food Engineering Food and NutritionUniversity of Wisconsin-StoutMenomonie WI 54751 USA

Pseudomonas putida KT217 produces medium-chain-length polyhydroxyalkanoate(mcl-PHA)that is of commercial interest as a biodegradable plastic.To reduce PHA production costs,a less expensive medium to grow P.putida KT217 to a high cell dry weight(CDW)was developed.P.putida KT217 was grown in aerated shake flasks on a condensed corn solubles(CCS)based medium that provided several organic acids and carbohydrates that were utilized for growth.The medium was prepared by adding various amounts of fresh CCS(100-600 g/L,or 34.9-209.4 g/L dry basis)to water and then centrifuging and filtering.The CCS permeate media contained dry matter levels of 28.8-164.9 g/L.The CCS permeate medium containing 108.4 g/L solids produced approximately 6 g CDW/L,at a growth rate of 1.03 per hour,and maximum cell population of 4×109 CFU/mL.Because CCS is low in nitrogen,ammonium hydroxide was added at a level of 1.73 g/L,and this significantly increased the CDW(>20 g/L)produced in an aerated bioreactor.Therefore,a nitrogen supplemented CCS medium could provide a cheap source of nutrients for production of P.putida KT217 and PHA.

关键词： cell density cell dry weight(CDW) biodegradable plastic biocreator pH nitrogen supplement growth rate

Effects of Various Light-Emitting Diode(LED)Wavelengths on the Growth of Scenedesmus Obliquus Fachb-12 and Accumulation of Astaxanthin

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Phyton-International Journal of Experimental Botany 2019年第3期88卷 335-348页

作者： Huabing Xu Xiaojuan Liu Zhiping Mei Jinchun Lin Stephan Aaron Hong Du Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center College of SciencesShantou UniversityShantou515063China ONCE Inc.1525523rd Ave N Plymouth MN 55447USA

Given the central role of light in the algal photosynthesis,respiration,cell division,growth and the accumulation of value products,the effects of light-emitting diodes(LEDs)light wavelengths(blue,white,red and green)were studied in Scenedesmus obliquus.Biomass,residual nutrient amount,soluble protein,astaxanthin and reactive oxygen species,superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)activity were analyzed to determine the effects of different monochromatic light wavelengths via biochemical methods.The results showed that blue light wavelength is the optimal light wavelength for phosphorus removal efficiency and the accumulation of biomass and astaxanthin in S.obliquus.Meanwhile,high reactive oxygen species content under the blue light might induce the accumulation of astaxanthin.The high activity of SOD,CAT and POD might participate in clearing the reactive oxygen species to facilitate the growth of microalgae.Furthermore,we found mixed blue/green lights treatment is the most appropriate mixture for the nitrogen removal.Under the blue light treatment,high light intensity and 18L:6D light cycle is the best condition for biomass and astaxanthin accumulation.Optimal nitrogen/phosphorus removal efficiency was observed under a 24L:0D light cycle.These results might provide a foundational data for the optimizing the productivity of high-value metabolites and treatment of wastewater.

关键词： Light-emitting diodes wavelength cell density nutrient removal efficiency astaxanthin