Publications by authors named "Jinxia Ma"

20 Publications

  • Page 1 of 1

Formation of filamentous fungal pellets in aerobic granular sludge via reducing temperature and dissolved oxygen: Characteristics of filamentous fungi and denitrification performance.

Bioresour Technol 2021 Jul 26;332:125056. Epub 2021 Mar 26.

School of Civil Engineering, Southeast University, Nanjing 210096, China. Electronic address:

A lab-scale sequencing batch reactor (SBR) using glucose as carbon source was operated for 500 days to investigate the formation of filamentous organisms and their function on stability of AGS system. After 250 days' stable operation under conditions of 25 ± 2 °C and dissolved oxygen (DO) of 4-5 mg/L (stage I), the temperature and DO were reduced to 10 ± 2 °C and DO of 1-2 mg/L until 280 days (stage II), to induce the growth of filamentous microorganisms. After that until 500 days (stage III), overgrowth of filamentous microorganisms with relative abundances of up to 19.46%, formation of black filamentous fungal pellets, and reconstruction of AGS granules were observed in turn. The relation between settling of AGS (SVI 30-72 mL/g) and filamentous microorganisms was revealed. Filamentous pellets were purified and identified as fungal Bradymyces and Knufia, with stronger denitrification performance on nitrite than nitrate. The results indicated that filamentous fungal pellets contributed to good sludge settling performance and promoted the denitrification process in AGS.
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http://dx.doi.org/10.1016/j.biortech.2021.125056DOI Listing
July 2021

Cellulose controlled zinc oxide nanoparticles with adjustable morphology and their photocatalytic performances.

Carbohydr Polym 2021 May 3;259:117752. Epub 2021 Feb 3.

Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, College of Light Industry and Food, Nanjing Forestry University, Nanjing, 210037, China. Electronic address:

The cellulose fibers with different size and aspect ratio was used as the matrix for the controllable preparation of zinc oxide (ZnO) to synthesize ZnO/cellulose composite catalyst with adjustable photocatalytic properties. The ZnO with different morphology of sphere, sheet, and flower, was in-situ synthesized on cellulose fibers by chemical deposition method, the flower-like ZnO supported on cellulose fiber exhibited the best photocatalytic activity. Furthermore, with the decrease of fiber size, the morphology of ZnO changed from most sheet to fully self-assembled flower shape, and the average thickness of nanosheets was increased. Cellulose fibers with smaller size and higher aspect ratio were more likely to form a 3D network structure with rich pores and stable mechanical properties. Significantly, with the decreasing of fiber size, ZnO/NFC has excellent photocatalytic efficiency (100 %). All ZnO/cellulose composites can be recycled more than five times.
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http://dx.doi.org/10.1016/j.carbpol.2021.117752DOI Listing
May 2021

Macro-/nanoporous Al-doped ZnO/cellulose composites based on tunable cellulose fiber sizes for enhancing photocatalytic properties.

Carbohydr Polym 2020 Dec 7;250:116873. Epub 2020 Aug 7.

Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, College of Light Industry and Food, Nanjing Forestry University, Nanjing, 210037, China; Zhejiang Hengda New Material Co. LTD, Longyou, 324401, China. Electronic address:

Porous Al-doped ZnO/cellulose (AZOC) composites were successfully fabricated via a chemical deposition method. The micro-/nano cellulose fibers (MNCF) with tunable sizes were prepared by grinding treatment, and used as substrates for synthesizing ZnO/MNCF and AZOC composites. With the increasing of grinding treatment times, the average fiber diameter of MNCF decreased, that of MNCF-10, MNCF-20 and MNCF-30 were 100 nm, 58 nm and 31 nm, which was observed by scanning electron microscopy (SEM). The fiber sizes of MNCF played an important role in the sizes of ZnO and Al-doped ZnO, also pore structures and photocatalytic properties of ZnO/MNCF and AZOC composites. The sizes of ZnO (or Al-doped ZnO) nanoparticles decreased with the decreasing of MNCF diameter. The AZOC composite with average fiber diameter of 31 nm (under grinding treatment of 30 times) exhibited the highest porosity (94.6 %). The obtained ZnO/MNCF and AZOC composites were further analyzed using X-ray diffraction (XRD), Raman spectrometry, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (DRS). Due to the introduction of Al element dopant, the AZOC showed a much better photocatalytic efficiency (89.9 %) than pure ZnO powders (22.5 %) and ZnO/MNCF composites (53.3 %). Moreover, the AZOC composite can be recycled more than 10 times with negligible photocatalytic efficiency loss.
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http://dx.doi.org/10.1016/j.carbpol.2020.116873DOI Listing
December 2020

Preparation of sugarcane bagasse nanocellulose hydrogel as a colourimetric freshness indicator for intelligent food packaging.

Carbohydr Polym 2020 Dec 1;249:116831. Epub 2020 Aug 1.

College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning 530004, China. Electronic address:

A sugarcane bagasse nanocellulose-based hydrogel was developed as a colourimetric freshness indicator for monitoring spoilage of chicken breast. Nanocellulose was prepared from sugarcane bagasse cellulose filaments by TEMPO-mediated oxidation, and then used to form a strong self-standing hydrogel matrix through Zn cross-linking. The hydrogel worked as a carrier for pH-responsive dyes (bromothymol blue/methyl red), which changed colour according to the freshness of the chicken sample. CO levels were found to increase with the spoilage of chicken, relative to rising levels of micro-organisms. The indicator hydrogel optical colour changed from green to red on the third day, as the log CFU/g passed the limit of acceptability for human consumption and emission of complicated volatiles. This new design of colourimetric freshness indicator made with a nanocellulose hydrogel has a quick response to chicken spoilage and is expected to facilitate the utilisation of bagasse nanocellulose as a value-added material in intelligent packaging.
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http://dx.doi.org/10.1016/j.carbpol.2020.116831DOI Listing
December 2020

Bio-based antimicrobial packaging from sugarcane bagasse nanocellulose/nisin hybrid films.

Int J Biol Macromol 2020 Oct 11;161:627-635. Epub 2020 Jun 11.

College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning 530004, China; Jiangsu Provincial Key Laboratory of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing, Jiangsu Province 210037, China. Electronic address:

Bio-based nanomaterials with antimicrobial functions hold promise in replacing petroleum-based packaging for food preservation. A nanocellulose-based hybrid film with antimicrobial properties was developed from sugarcane bagasse and nisin. Cellulose nanofibrils (CNFs) were prepared from sugarcane bagasse pulp by mechanical grinding, and mixed with nisin to prepare CNFs/nisin nanohybrid films. The concentration of nisin has a remarkable influence on the mechanical, light transmission, gas barrier, and antimicrobial properties of these films. CNFs/nisin hybrid films with 1920 mg/L nisin exhibit good light transmission, relatively high tensile strength, low oxygen permeability, and low water vapor transmission rates. This hybrid film was used as a liner of low-density polyethylene plastic packaging for ready-to-eat ham; it completely inhibited Listeria monocytogenes during 7 days of storage at 4 °C. Such novel CNFs/nisin nanohybrid films are expected to expand the application of bagasse nanocellulose in active packaging for food preservation.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.06.081DOI Listing
October 2020

Application of droplet digital PCR for the detection of vector copy number in clinical CAR/TCR T cell products.

J Transl Med 2020 05 8;18(1):191. Epub 2020 May 8.

Center for Cellular Engineering, Department of Transfusion Medicine and Cellular Engineering, NIH Clinical Center, Bethesda, MD, USA.

Background: Genetically engineered T cells have become an important therapy for B-cell malignancies. Measuring the efficiency of vector integration into the T cell genome is important for assessing the potency and safety of these cancer immunotherapies.

Methods: A digital droplet polymerase chain reaction (ddPCR) assay was developed and evaluated for assessing the average number of lenti- and retroviral vectors integrated into Chimeric Antigen Receptor (CAR) and T Cell Receptor (TCR)-engineered T cells.

Results: The ddPCR assay consistently measured the concentration of an empty vector in solution and the average number of CAR and TCR vectors integrated into T cell populations. There was a linear relationship between the average vector copy number per cell measured by ddPCR and the proportion of cells transduced as measured by flow cytometry. Similar vector copy number measurements were obtained by different staff using the ddPCR assay, highlighting the assays reproducibility among technicians. Analysis of fresh and cryopreserved CAR T and TCR engineered T cells yielded similar results.

Conclusions: ddPCR is a robust tool for accurate quantitation of average vector copy number in CAR and TCR engineered T cells. The assay is also applicable to other types of genetically engineered cells including Natural Killer cells and hematopoietic stem cells.
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http://dx.doi.org/10.1186/s12967-020-02358-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7206671PMC
May 2020

The development of colitis in Il10 mice is dependent on IL-22.

Mucosal Immunol 2020 05 13;13(3):493-506. Epub 2020 Jan 13.

Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.

Mice deficient in the IL-10 pathway are the most widely used models of intestinal immunopathology. IL-17A is strongly implicated in gut disease in mice and humans, but conflicting evidence has drawn IL-17's role in the gut into question. IL-22 regulates antimicrobial and repair activities of intestinal epithelial cells (IECs) and is closely associated with IL-17A responses but it's role in chronic disease is uncertain. We report that IL-22, like IL-17A, is aberrantly expressed in colitic Il10 mice. While IL-22Th17 cells were elevated in the colon, IL-22-producing ILC3s were highly enriched in the small intestines of Il10 mice. Remarkably, Il10Il22 mice did not develop colitis despite retaining high levels of Th17 cells and remaining colonized with colitogenic Helicobacter spp. Accordant with IL-22-induced IEC proliferation, the epithelia hyperplasia observed in Il10 animals was reversed in Il10Il22 mice. Also, the high levels of antimicrobial IL-22-target genes, including Reg3g, were normalized in Il10Il22 mice. Consistent with a heightened antimicrobial environment, Il10 mice had reduced diversity of the fecal microbiome that was reestablished in Il10Il22 animals. These data suggest that spontaneous colitis in Il10 mice is driven by IL-22 and implicates an underappreciated IL-10/IL-22 axis in regulating intestinal homeostasis.
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http://dx.doi.org/10.1038/s41385-019-0252-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7566780PMC
May 2020

[Clinical and genetic analysis of a patient with Hb Ottawa in conjunction with β -thalassemia].

Zhonghua Yi Xue Yi Chuan Xue Za Zhi 2019 Nov;36(11):1130-1132

Shantou Central Hospital, Shantou, Guangdong 515041, China.

Objective: To analyze the hematological characteristics of a patient with Hb Ottawa in conjunction with β -thalassemia.

Methods: Peripheral blood samples from the proband and her parents were collected and subjected to red blood cell analysis and hemoglobin electrophoresis. Genotypes of α - and β -globin genes were also analyzed.

Results: The proband and her mother were both heterozygotes for Hb Ottawa and β -thalassemia variant IVS II-654, and presented with typical β -thalassemia trait featuring hypochromic microcytic anemia. An abnormal hemoglobin band was detected upon electrophoresis.

Conclusion: Co-existence of Hb Ottawa and β -thalassemia may not aggravate the phenotype.
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http://dx.doi.org/10.3760/cma.j.issn.1003-9406.2019.11.019DOI Listing
November 2019

Costunolide induces mitochondria-mediated apoptosis in human gastric adenocarcinoma BGC-823 cells.

BMC Complement Altern Med 2019 Jun 26;19(1):151. Epub 2019 Jun 26.

Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu, China.

Background: Costunolide, a sesquiterpene lactone extracted from Radix Aucklandiae, has the activity against multiple cancers. However, the effect of costunolide on gastric cancer (GC) have remained to be ambiguous. In this study, we investigated the underlying mechanisms of apoptosis induced by costunolide in human gastric adenocarcinoma BGC-823 cells in vitro and in vivo.

Methods: The viability of BGC-823 cells was detected by MTT assay. The apoptosis and mitochondrial membrane potential (ΔΨm) of BGC-823 cells induced by costunolide were analyzed by flow cytometry. The inhibiton of costunolide on human gastric adenocarcinoma was estimated in xenografts in nude mice. Apoptosis related proteins and genes were detected by Western blot and Q-PCR.

Results: Costunolide inhibited the viability of BGC-823 cells in a time and concentration dependent manner. Costunolide induced the apoptosis and lowered the ΔΨm of BGC-823 cells significantly. Costunolide increased the expression of Bax, cleaved caspase 9, cleaved caspase 7, cleaved caspase 3 and cleaved poly ADP ribose polymerase (PARP) proteins and decreased the expression of Bcl-2, pro-caspase 9, pro-caspase 7, pro-caspase 3 and PARP proteins. Costunolide upregulated the expression of puma, Bak1 and Bax mRNA and downregulated the expression of Bcl-2 mRNA. In addition, we demonstrated that costunolide inhibited the growth and induced apoptosis of BGC-823 cells xenografted in athymic nude mice. Costunolide increased the expression of cleaved caspase 9, cleaved caspase 3 and Bax proteins and decreased the expression of Bcl-2 protein in xenografted tumor. Costunolide upregulated the expression of puma and Bax mRNA and decreased the expression of Bcl-2 mRNA in xenografted tumor.

Conclusions: Collectively, our results suggested that costunolide induced mitochondria-mediated apoptosis in human gastric adenocarcinoma BGC-823 cells and could be the candidate drug against GC in clinical practice.
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http://dx.doi.org/10.1186/s12906-019-2569-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6595696PMC
June 2019

Nano-Cellulose/MOF Derived Carbon Doped CuO/Fe₃O₄ Nanocomposite as High Efficient Catalyst for Organic Pollutant Remedy.

Nanomaterials (Basel) 2019 Feb 16;9(2). Epub 2019 Feb 16.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

Metal⁻organic framework (MOF)-based derivatives are attracting increased interest in various research fields. In this study, nano-cellulose MOF-derived carbon-doped CuO/Fe₃O₄ nanocomposites were successfully synthesized via direct calcination of magnetic Cu-BTC MOF (HKUST-1)/Fe₃O₄/cellulose microfibril (CMF) composites in air. The morphology, structure, and porous properties of carbon-doped CuO/Fe₃O₄ nanocomposites were characterized using SEM, TEM, powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The results show that the as-prepared nanocomposite catalyst is composed of Fe₃O₄, CuO, and carbon. Compared to the CuO/Fe₃O₄ catalyst from HKUST-1/Fe₃O₄ composite and CuO from HKUST-1, this carbon-doped CuO/Fe₃O₄ nanocomposite catalyst shows better catalytic efficiency in reduction reactions of 4-nitrophenol (4-NP), methylene blue (MB), and methyl orange (MO) in the presence of NaBH₄. The enhanced catalytic performance of carbon-doped CuO/Fe₃O₄ is attributed to effects of carbon preventing the aggregation of CuO/Fe₃O₄ and providing high surface-to-volume ratio and chemical stability. Moreover, this nanocomposite catalyst is readily recoverable using an external magnet due to its superparamagnetic behavior. The recyclability/reuse of carbon-doped CuO/Fe₃O₄ was also investigated.
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http://dx.doi.org/10.3390/nano9020277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6410010PMC
February 2019

A Facile Approach for the Preparation of Nano-size Zinc Oxide in Water/Glycerol with Extremely Concentrated Zinc Sources.

Nanoscale Res Lett 2018 Jul 9;13(1):202. Epub 2018 Jul 9.

Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China.

A facile process to prepare zinc oxide (ZnO) nanoparticles from an aqueous zinc chloride (ZnCl) solution and an aqueous hydroxide solution under a glycerol stabilizer at room temperature was developed. ZnCl aqueous solutions as concentrated as 65-80 wt% were used as the concentrated zinc source. The concentration of ZnCl solutions and the molar ratio of glycerol to Zn had obvious effects on the sizes and shapes of the ZnO nanoparticles. The shape of ZnO nanoparticles changed from rods approximately 50-120 nm long and 30-70 nm in diameter to globular with diameters of approximately 20 nm with the increasing of the concentration of the ZnCl solution and the mole ratio of glycerol to Zn. Glycerol, as a stabilizer, played an important role in the formation of ZnO nanostructures at room temperature, even for a highly concentrated zinc source.
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http://dx.doi.org/10.1186/s11671-018-2616-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6037639PMC
July 2018

Recent Developments of Graphene Oxide-Based Membranes: A Review.

Membranes (Basel) 2017 Sep 12;7(3). Epub 2017 Sep 12.

School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.

Membrane-based separation technology has attracted great interest in many separation fields due to its advantages of easy-operation, energy-efficiency, easy scale-up, and environmental friendliness. The development of novel membrane materials and membrane structures is an urgent demand to promote membrane-based separation technology. Graphene oxide (GO), as an emerging star nano-building material, has showed great potential in the membrane-based separation field. In this review paper, the latest research progress in GO-based membranes focused on adjusting membrane structure and enhancing their mechanical strength as well as structural stability in aqueous environment is highlighted and discussed in detail. First, we briefly reviewed the preparation and characterization of GO. Then, the preparation method, characterization, and type of GO-based membrane are summarized. Finally, the advancements of GO-based membrane in adjusting membrane structure and enhancing their mechanical strength, as well as structural stability in aqueous environment, are particularly discussed. This review hopefully provides a new avenue for the innovative developments of GO-based membrane in various membrane applications.
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http://dx.doi.org/10.3390/membranes7030052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618137PMC
September 2017

Preparation of Zinc Oxide-Starch Nanocomposite and Its Application on Coating.

Nanoscale Res Lett 2016 Dec 14;11(1):200. Epub 2016 Apr 14.

Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, 159 Longpan Road, Nanjing, 210037, China.

A new production method of zinc oxide (ZnO)-starch nanocomposite was invented in this study. Starch was dissolved in zinc chloride (ZnCl2) solution (65 wt%) at 80 °C. Then, ZnO-starch nanocomposite was achieved when the pH of the solution was adjusted to 8.4 by NaOH solution (15 wt%). ZnO nanoparticles were also obtained when the generated ZnO-starch nanocomposite was calcined at 575 °C. The properties of ZnO-starch nanocomposite and ZnO nanoparticle were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the sizes of ZnO-starch composite and ZnO particle were 40-60 nm. UV blocking effect was observed from both ZnO-starch nanocomposite and ZnO nanoparticle. The ZnO-starch nanocomposite was used to directly coat the surface of plain paper with a laboratory paper coater. The surface strength and smoothness of paper were improved by the coating of ZnO-starch nanocomposite. The antibacterial property was also identified from the coated paper.
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http://dx.doi.org/10.1186/s11671-016-1404-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4830787PMC
December 2016

Preparation and Characterization of Self-Reinforced Antibacterial and Oil-Resistant Paper Using a NaOH/Urea/ZnO Solution.

PLoS One 2015 14;10(10):e0140603. Epub 2015 Oct 14.

Department of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing, Jiangsu, China.

This paper describes self-reinforced antibacterial and oil-resistant properties that were successfully prepared by surface selective dissolution of filter paper in a NaOH/Urea/ZnO (weight ratio of 8:12:0.25) aqueous solution. The effect of the processing time on the mechanical properties of this paper was evaluated at -12°C. The paper morphologies were characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The oil-resistance and antibacterial properties of the produced paper were also investigated. Excellent mechanical properties were observed for an optimized handling time. The tensile and burst strengths of the modified paper were in excess of 100% of the original. Meanwhile, the treated paper was completely oil-resistant within 24 h and demonstrated good antibacterial properties when exposed to Staphylococcus aureus. The traces of residual zinc oxide were found to be safe for food.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0140603PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4605556PMC
June 2016

Flow Cytometry Based Detection and Isolation of Plasmodium falciparum Liver Stages In Vitro.

PLoS One 2015 12;10(6):e0129623. Epub 2015 Jun 12.

W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, United States of America.

Malaria, the disease caused by Plasmodium parasites, remains a major global health burden. The liver stage of Plasmodium falciparum infection is a leading target for immunological and pharmacological interventions. Therefore, novel approaches providing specific detection and isolation of live P. falciparum exoerythrocytic forms (EEFs) are warranted. Utilizing a recently generated parasite strain expressing green fluorescent protein (GFP) we established a method which, allows for detection and isolation of developing live P. falciparum liver stages by flow cytometry. Using this technique we compared the susceptibility of five immortalized human hepatocyte cell lines and primary hepatocyte cultures from three donors to infection by P. falciparum sporozoites. Here, we show that EEFs can be detected and isolated from in vitro infected cultures of the HC-04 cell line and primary human hepatocytes. We confirmed the presence of developing parasites in sorted live human hepatocytes and characterized their morphology by fluorescence microscopy. Finally, we validated the practical applications of our approach by re-examining the importance of host ligand CD81 for hepatocyte infection by P. falciparum sporozoites in vitro and assessment of the inhibitory activity of anti-sporozoite antibodies. This methodology provides us with the tools to study both, the basic biology of the P. falciparum liver stage and the effects of host-derived factors on the development of P. falciparum EEFs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0129623PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4466555PMC
March 2016

Dynamics of the major histocompatibility complex class I processing and presentation pathway in the course of malaria parasite development in human hepatocytes: implications for vaccine development.

PLoS One 2013 25;8(9):e75321. Epub 2013 Sep 25.

W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America.

Control of parasite replication exerted by MHC class I restricted CD8+ T-cells in the liver is critical for vaccination-induced protection against malaria. While many intracellular pathogens subvert the MHC class I presentation machinery, its functionality in the course of malaria replication in hepatocytes has not been characterized. Using experimental systems based on specific identification, isolation and analysis of human hepatocytes infected with P. berghei ANKA GFP or P. falciparum 3D7 GFP sporozoites we demonstrated that molecular components of the MHC class I pathway exhibit largely unaltered expression in malaria-infected hepatocytes until very late stages of parasite development. Furthermore, infected cells showed no obvious defects in their capacity to upregulate expression of different molecular components of the MHC class I machinery in response to pro-inflammatory lymphokines or trigger direct activation of allo-specific or peptide-specific human CD8+ T-cells. We further demonstrate that ectopic expression of circumsporozoite protein does not alter expression of critical genes of the MHC class I pathway and its response to pro-inflammatory cytokines. In addition, we identified supra-cellular structures, which arose at late stages of parasite replication, possessed the characteristic morphology of merosomes and exhibited nearly complete loss of surface MHC class I expression. These data have multiple implications for our understanding of natural T-cell immunity against malaria and may promote development of novel, efficient anti-malaria vaccines overcoming immune escape of the parasite in the liver.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0075321PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3783408PMC
July 2014

Syntaxin 11 marks a distinct intracellular compartment recruited to the immunological synapse of NK cells to colocalize with cytotoxic granules.

J Cell Mol Med 2012 Jan;16(1):129-41

Department of Oncology, The Johns Hopkins University School of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA.

The syntaxin 11 (STX11) gene is mutated in a proportion of patients with familial haemophagocytic lymphohistiocytosis (FHL) and exocytosis of cytotoxic granules is impaired in STX11-deficient NK cells. However, the subcellular localization, regulation of expression and molecular function of STX11 in NK cells and other cytotoxic lymphocytes remain unknown. Here we demonstrate that STX11 expression is strictly controlled by several mechanisms in a cell-type-specific manner and that the enzymatic activity of the proteasome is required for STX11 expression in NK cells. In resting NKL cells, STX11 was localized in the cation-dependent mannose-6-phosphate receptor (CD-M6PR)-containing compartment, which was clearly distinct from cytotoxic granules or Rab27a-expressing vesicles. These subcellular structures appeared to fuse at the contact area with NK-sensitive target cells as demonstrated by partial colocalization of STX11 with perforin and Rab27a. Although STX11-deficent allo-specific cytotoxic T-lymphocytes efficiently lysed target cells and released cytotoxic granules, they exhibited a significantly lower extent of spontaneous association of perforin with Rab27a as compared with STX11-expressing T cells. Thus, our results suggest that STX11 promotes the fusion of Rab27a-expressing vesicles with cytotoxic granules and reveal an additional level of complexity in the spatial/temporal segregation of subcellular structures participating in the process of granule-mediated cytotoxicity.
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http://dx.doi.org/10.1111/j.1582-4934.2011.01280.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823099PMC
January 2012

Single-molecule and FRET fluorescence correlation spectroscopy analyses of phage DNA packaging: colocalization of packaged phage T4 DNA ends within the capsid.

J Mol Biol 2010 Feb 4;395(5):1102-13. Epub 2009 Dec 4.

Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA.

Linear DNAs of any sequence can be packaged into empty viral procapsids by the phage T4 terminase with high efficiency in vitro. Packaging substrates of 5 kbp and 50 kbp, terminated by energy transfer dye pairs, were constructed from plasmid and lambda phage DNAs. Nuclease and fluorescence correlation spectroscopy (FCS) assays showed that approximately 20% of the substrate DNA was packaged and that the DNA dye ends of the packaged DNA were protected from nuclease digestion. Upon packaging, both 5-kbp and 50-kbp DNAs produced comparable fluorescence resonance energy transfer (FRET) between Cy5 and Cy5.5 double-dye terminated DNAs. Single-molecule FRET (sm-FRET) and photobleaching analysis shows that FRET is intramolecular rather than intermolecular upon packaging of most procapsids and demonstrates that single-molecule detection allows mechanistic analysis of packaging in vitro. FRET-FCS and sm-FRET measurements are comparable and show that both the 5-kbp and the 50-kbp packaged DNA ends are held within 8-9 nm of each other, within the dimensions of the long axis of the procapsid portal. The calculated distribution of FRET distances is relatively narrow for both FRET-FCS and sm-FRET, suggesting that the two packaged DNA ends are held at the same fixed distance relative to each other in most capsids. Because one DNA end is known to be positioned for ejection through the portal, it can be inferred that both DNAs ends are held in proximity to the portal entrance and ejection channel. The analysis suggests that a DNA loop, rather than a DNA end, is translocated by the packaging motor to fill the procapsid.
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http://dx.doi.org/10.1016/j.jmb.2009.11.067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813382PMC
February 2010

Portal control of viral prohead expansion and DNA packaging.

Virology 2009 Aug 21;391(1):44-50. Epub 2009 Jun 21.

Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.

Bacteriophage T4 terminase packages DNA in vitro into empty small or large proheads (esps or elps). In vivo maturation of esps yields the more stable and voluminous elps required to contain the 170 kb T4 genome. Functional proheads can be assembled containing portal-GFP fusion proteins. In the absence of terminase activity these accumulated in esps in vivo, whereas wild-type portals were found in elps. By nuclease protection assay dsDNAs of lengths 0.1, 0.2, 0.5, 5, 11, 20, 40 or 170 kb were efficiently packaged into wild-type elps in vitro, but less so into esps and gp20-GFP elps; particularly with DNAs shorter than 11 kb. However, 0.1 kb substrates were equally efficiently packaged into all types of proheads as judged by fluorescence correlation spectroscopy. These data suggest the portal controls the expansion of the major capsid protein lattice during prohead maturation, and that this expansion is necessary for DNA protection but not for packaging.
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http://dx.doi.org/10.1016/j.virol.2009.05.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2739799PMC
August 2009

Zm401, a short-open reading-frame mRNA or noncoding RNA, is essential for tapetum and microspore development and can regulate the floret formation in maize.

J Cell Biochem 2008 Sep;105(1):136-46

State key Laboratories of Agrobiotechnology, China Agricultural University, Beijing 100094, China.

In flowering plants, pollen formation depends on the differentiation and interaction of two cell types in the anther: the reproductive cells, called microsporocytes, and somatic cells that form the tapetum. Previously, we cloned a pollen specific gene, zm401, from a cDNA library generated from the mature pollen of Zea mays. Expression of partial cDNA of zm401 in maize and ectopic expression of zm401 in tobacco suggested it may play a role in anther development. Here we present the expression and functional characterization of this pollen specific gene in maize. Zm401 is expressed primarily in the anthers (tapetal cells as well as microspores) in a developmentally regulated manner. That is, it is expressed from floret forming stage, increasing in concentration up to mature pollen. Knockdown of zm401 significantly affected the expression of ZmMADS2, MZm3-3, and ZmC5, critical genes for pollen development; led to aberrant development of the microspore and tapetum, and finally male-sterility. Zm401 possesses highly conserved sequences and evolutionary conserved stable RNA secondary structure in monocotyledon. These data show that zm401 could be one of the key growth regulators in anther development, and functions as a short-open reading-frame mRNA (sORF mRNA) and/or noncoding RNA (ncRNA).
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http://dx.doi.org/10.1002/jcb.21807DOI Listing
September 2008