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1.
Chemosphere ; 362: 142769, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38969227

ABSTRACT

Recycling and reuse of agricultural plastics is an urgent worldwide issue. In this work, it is shown that low-density polyethylene (PE) typically used in mulch films can be converted into high-capacity P and N adsorbents through a two-step method that uses hydrothermal pretreatment (180 °C, 24 h) followed by pyrolysis at 500 °C with Ca(OH)2 additive. CaPE@HC500 materials prepared with the proposed two-step method were found to have high adsorption capacities for phosphate (263.6 mg/g) and nitrogen (200.7 mg/g) over wide ranges of pH (3-11). Dynamic adsorption of phosphate by CaPE@HC500 material in a packed-bed had a half-time breakthrough of 210 min indicating the feasibility of continuous systems. Material stability, cost, environmental-friendliness, and recyclability of the CaPE@HC500 material were determined to be superior to literature-proposed Ca-containing adsorbents. The two-step method for converting waste agricultural plastic mulch films into adsorbents is robust and highly-applicable to industrial settings.

2.
Elife ; 122023 Jul 06.
Article in English | MEDLINE | ID: mdl-37410519

ABSTRACT

Here, we present the first analysis of the connectome of a small volume of the Octopus vulgaris vertical lobe (VL), a brain structure mediating the acquisition of long-term memory in this behaviorally advanced mollusk. Serial section electron microscopy revealed new types of interneurons, cellular components of extensive modulatory systems, and multiple synaptic motifs. The sensory input to the VL is conveyed via~1.8 × 106 axons that sparsely innervate two parallel and interconnected feedforward networks formed by the two types of amacrine interneurons (AM), simple AMs (SAMs) and complex AMs (CAMs). SAMs make up 89.3% of the~25 × 106VL cells, each receiving a synaptic input from only a single input neuron on its non-bifurcating primary neurite, suggesting that each input neuron is represented in only~12 ± 3.4SAMs. This synaptic site is likely a 'memory site' as it is endowed with LTP. The CAMs, a newly described AM type, comprise 1.6% of the VL cells. Their bifurcating neurites integrate multiple inputs from the input axons and SAMs. While the SAM network appears to feedforward sparse 'memorizable' sensory representations to the VL output layer, the CAMs appear to monitor global activity and feedforward a balancing inhibition for 'sharpening' the stimulus-specific VL output. While sharing morphological and wiring features with circuits supporting associative learning in other animals, the VL has evolved a unique circuit that enables associative learning based on feedforward information flow.


Subject(s)
Connectome , Octopodiformes , Animals , Octopodiformes/physiology , Memory/physiology , Neurons/physiology , Brain/physiology
3.
Viruses ; 15(3)2023 03 14.
Article in English | MEDLINE | ID: mdl-36992456

ABSTRACT

Rhinoviruses (RVs) are major instigators of acute exacerbations of asthma, COPD, and other respiratory diseases. RVs are categorized into three species (RV-A, RV-B, and RV-C), which comprise more than 160 serotypes, making it difficult to develop an effective vaccine. Currently, no effective treatment for RV infection is available. Pulmonary surfactant is an extracellular complex of lipids and proteins that plays a central role in regulating innate immunity in the lung. The minor pulmonary surfactant lipids, palmitoyl-oleoyl-phosphatidylglycerol (POPG) and phosphatidylinositol (PI), are potent regulators of inflammatory processes and exert antiviral activity against respiratory syncytial virus (RSV) and influenza A viruses (IAV). In the current study, we examined the potencies of POPG and PI against rhinovirus A16 (RV-A16) in primary human airway epithelial cells (AECs) differentiated at an air-liquid interface (ALI). After AECs were infected with RV-A16, PI reduced the viral RNA copy number by 70% and downregulated (55-75%) the expression of antiviral (MDA5, IRF7, and IFN-lambda) and CXCL11 chemokine genes. In contrast, POPG only slightly decreased MDA5 (24%) and IRF7 (11%) gene expression but did not inhibit IFN-lambda gene expression or RV-A16 replication in AECs. However, both POPG and PI inhibited (50-80%) IL6 gene expression and protein secretion and CXCL11 protein secretion. PI treatment dramatically attenuated global gene expression changes induced by RV-A16 infection alone in AECs. The observed inhibitory effects were indirect and resulted mainly from the inhibition of virus replication. Cell-type enrichment analysis of viral-regulated genes opposed by PI treatment revealed the PI-inhibited viral induction of goblet cell metaplasia and the virus-induced downregulation of ciliated, club, and ionocyte cell types. Notably, the PI treatment also altered the ability of RV-A16 to regulate the expression of some phosphatidylinositol 4-kinase (PI4K); acyl-CoA-binding, domain-containing (ACBD); and low-density lipoprotein receptor (LDLR) genes that play critical roles in the formation and functioning of replication organelles (ROs) required for RV replication in host cells. These data suggest PI can be used as a potent, non-toxic, antiviral agent for RV infection prophylaxis and treatment.


Subject(s)
Enterovirus Infections , Picornaviridae Infections , Pulmonary Surfactants , Humans , Pulmonary Surfactants/pharmacology , Rhinovirus/genetics , Epithelial Cells , Epithelium/metabolism , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Enterovirus Infections/drug therapy , Lung/metabolism , Lipids
4.
Nat Commun ; 14(1): 200, 2023 01 13.
Article in English | MEDLINE | ID: mdl-36639371

ABSTRACT

Immune system molecules are expressed by neurons, yet their functions are often unknown. We have identified IL-13 and its receptor IL-13Ra1 as neuronal, synaptic proteins in mouse, rat, and human brains, whose engagement upregulates the phosphorylation of NMDAR and AMPAR subunits and, in turn, increases synaptic activity and CREB-mediated transcription. We demonstrate that increased IL-13 is a hallmark of traumatic brain injury (TBI) in male mice as well as in two distinct cohorts of human patients. We also provide evidence that IL-13 upregulation protects neurons from excitotoxic death. We show IL-13 upregulation occurring in several cohorts of human brain samples and in cerebrospinal fluid (CSF). Thus, IL-13 is a physiological modulator of synaptic physiology of neuronal origin, with implications for the establishment of synaptic plasticity and the survival of neurons under injury conditions. Furthermore, we suggest that the neuroprotection afforded through the upregulation of IL-13 represents an entry point for interventions in the pathophysiology of TBI.


Subject(s)
Brain Injuries, Traumatic , Interleukin-13 , Neuronal Plasticity , Animals , Humans , Male , Mice , Rats , Brain Injuries, Traumatic/genetics , Brain Injuries, Traumatic/metabolism , Interleukin-13/genetics , Interleukin-13/metabolism , Neuronal Plasticity/physiology , Neurons/metabolism , Neuroprotection
5.
Dent Mater J ; 42(2): 228-235, 2023 Mar 30.
Article in English | MEDLINE | ID: mdl-36464292

ABSTRACT

Because nicotine upregulates the growth of most oral bacteria, this in vitro study investigated the antimicrobial effect of chlorhexidine-doped thin film on commercially pure titanium against Fusobacterium nucleatum (F. nucleatum) biofilm supplemented with different concentrations of nicotine (0, 1, and 2 mg/mL). Biofilms were formed on a chlorhexidine-doped thin film on commercially-pure-titanium discs and compared to the control groups. Biofilm viability, total biofilm growth using a spectrophotometer, extracellular polysaccharide content, and pH variations were assessed as dependent variables. Data were submitted to ANOVA and Tukey honest significant difference tests (α=0.05). F. nucleatum biofilm growth was inhibited when exposed to chlorhexidine-doped thin film (p<0.05). Biofilm supplemented with nicotine did not impact the synthesis of EPS on the same type of treatment (p>0.05). The pH values were significantly increased with the increase of nicotine concentration (p<0.05). Chlorhexidine-doped thin film was effective in reducing F. nucleatum biofilm supplemented with nicotine.


Subject(s)
Anti-Infective Agents , Chlorhexidine , Chlorhexidine/pharmacology , Titanium/pharmacology , Titanium/chemistry , Nicotine/pharmacology , Anti-Infective Agents/pharmacology , Biofilms , Fusobacterium nucleatum
6.
J Environ Qual ; 52(3): 434-447, 2023.
Article in English | MEDLINE | ID: mdl-34894404

ABSTRACT

Understanding indicators of soil health is crucial for developing agricultural systems that are sustainable and climate resilient. Labile soil carbon (C), microbial properties, and nutrient status are all incorporated into the Haney Soil Health Tool with the goal of summarizing several indicators into one index. Monthly soil samples from an integrated crop-livestock system in Central Texas were collected from 2017 to 2019. Fields represented a range of management practices, including cover crops, no-till, rotational grazing, and a native prairie remnant. Soil samples were analyzed for total C, water-soluble C, macro- and micronutrient content and bioavailability, and phospholipid fatty acids (PLFAs). Microbial activity was determined via a 24-h CO2 incubation. Soil health score, C, and PLFAs were well correlated with each other. The greatest total PLFA (219.5 nmol g-1 soil) and organic C (54.3 g kg-1 soil) were found in the native prairie, and the lowest were found in the unfertilized continuous-corn system (60.5 nmol PLFAs g-1 soil and 24.0 g organic C kg-1 soil). Of all agroecosystems, the perennial grazing system (soil health score, 24.7) was most similar to the native prairie (soil health score, 27.4), having high soil C and a large microbial community. Of the row cropping systems, the no-till system approached the perennial systems better than the conventional till and unfertilized conventional till (soil health score, 11.1 vs. 8.0 and 5.3, respectively). This study highlights the value of perennial grass grazing in agroecosystems and appropriate best management practices. Expanding this analysis to other sites may provide additional insight.


Subject(s)
Microbiota , Soil , Animals , Livestock , Agriculture , Crops, Agricultural , Carbon
7.
Braz. j. oral sci ; 22: e231137, Jan.-Dec. 2023. ilus
Article in English | LILACS, BBO - Dentistry | ID: biblio-1523140

ABSTRACT

The purpose of this in vitro study was to analyze the influence of nicotine on the extracellular polysaccharides in Fusobacterium nucleatum biofilm. Methods: F. nucleatum (ATCC 10953) biofilms supplemented with different concentrations of nicotine (0, 0.5, 1, 2, 4, and 8 mg/mL) were grown in two different BHI broth conditions [no sucrose and 1% sucrose]. Extracellular polysaccharides assay, pH measurements, and a spectrophotometric assay were performed. Data were submitted for ANOVA and Tukey honestly significant difference analyses (HSD) tests (α =.05). Results: Extracellular polysaccharides synthesis was influenced by an interaction between nicotine concentrations and growth medium solution containing sucrose (P<.05). The pH values declined in the sucrose-exposed biofilm were greater than in the group exposed only to nicotine (P<.05). The biofilm exposed to sucrose and nicotine had a higher total biofilm growth (P<.05) than the nicotine-treated biofilm without sucrose. Conclusions: Regardless of sucrose exposure, biofilms exposed to different nicotine concentrations influenced the amount of extracellular polysaccharides


Subject(s)
Humans , Polysaccharides, Bacterial/chemical synthesis , Fusobacterium nucleatum/growth & development , Biofilms/growth & development , Nicotine/pharmacology , Periodontal Diseases/microbiology , Spectrophotometry , Sucrose/administration & dosage , Culture Media , Dental Caries/microbiology , Nicotine/administration & dosage
8.
Preprint in English | bioRxiv | ID: ppbiorxiv-504912

ABSTRACT

Exhaled human breath contains a rich mixture of volatile organic compounds (VOCs) whose concentration can vary in response to disease or other stressors. Using simulated odorant-binding proteins (OBPs) and machine learning methods, we designed a multiplex of short VOC- and carbon-binding peptide probes that detect the characteristic "VOC fingerprint". Specifically, we target VOCs associated with COVID-19 in a compact, molecular sensor array that directly transduces vapor composition into multi-channel electrical signals. Rapidly synthesizable, chimeric VOC- and solid-binding peptides were derived from selected OBPs using multi-sequence alignment with protein database structures. Selective peptide binding to targeted VOCs and sensor surfaces was validated using surface plasmon resonance spectroscopy and quartz crystal microbalance. VOC sensing was demonstrated by peptide-sensitized, exposed-channel carbon nanotube transistors. The data-to-device pipeline enables the development of novel devices for non-invasive monitoring, diagnostics of diseases, and environmental exposures assessment.

9.
J Hazard Mater ; 436: 129109, 2022 Aug 15.
Article in English | MEDLINE | ID: mdl-35594674

ABSTRACT

In coal-combustion energy production, presence of water vapor in flue gas causes catalyst deactivation and leads to the release of large quantities of volatile organic compounds (VOCs). In this study, design of a low-temperature, hydrophobic catalyst for flue gas purification was achieved by modifying support material with inorganic siloxane. Introduction of 5% water vapor into simulated flue gas at 300 °C reduced oxidation efficiency for o-xylene removal by 26% with unmodified MnOx/γ-Al2O3 catalyst, whereas with modified catalyst MnOx-Si0.9/γ-Al2O3 oxidation efficiency was reduced by only 5%. MnOx-Si0.9/γ-Al2O3 exhibited stable catalytic efficiency for o-xylene gas oxidation containing water vapor for over 200 min. Water-resistance of the catalyst was effective for removal of multi-coal combustion pollutants (Hg0 and NO) and moreover, hydrophobicity of the catalyst led to a reduction in surface sulfate deposition, thereby lowering toxicity of SO2 from simulated flue gas. DRIFTS analysis showed that the hydrophobic catalyst surface not only reduces water adsorption, but also promotes water volatilization. Based on molecular adsorption energies, catalyst support modification with siloxane inhibits water adsorption and promotes organic adsorption and thus provides a new strategy for preparing water-resistant catalysts for flue gas purification.

10.
Environ Sci Pollut Res Int ; 28(39): 55725-55735, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34138434

ABSTRACT

In this work, hydrothermal leaching was applied to simulated soils (clay minerals vermiculite, montmorillonite, and kaolinite) and actual soils (Terunuma, Japan) to generate organic acids with the objective to develop an additive-free screening method for determination of Sr in soil. Stable strontium (SrCl2) was adsorbed onto soils for the study, and ten organic acids (citric, L(+)-tartaric, succinic, oxalic, pyruvic, formic, glycolic, lactic, acetic, and propionic) were evaluated for leaching Sr from simulated soils under hydrothermal conditions (120 °C to 200 °C) at concentrations up to 0.3 M. For strontium-adsorbed vermiculite (Sr-V), 0.1 M citric acid was found to be effective for leaching Sr at 150 °C and 1 h treatment time. Based on these results, the formation of organic acids from organic matter in Terunuma soil was studied. Hydrothermal treatment of Terunuma soil produced a maximum amount of organic acids at 200 °C and 0.5 h reaction time. To confirm the possibility for leaching of Sr from Terunuma soil, strontium-adsorbed Terunuma soil (Sr-S) was studied. For Sr-S, hydrothermal treatment at 200 °C for 0.5 h reaction time allowed 40% of the Sr to be leached at room temperature, thus demonstrating an additive-free method for screening of Sr in soil. The additive-free hydrothermal leaching method avoids calcination of solids in the first step of chemical analysis and has application to both routine monitoring of metals in soils and to emergency situations.


Subject(s)
Soil , Strontium , Japan , Research
11.
Nutr Res ; 86: 60-67, 2021 02.
Article in English | MEDLINE | ID: mdl-33551256

ABSTRACT

The dramatic increase of people affected by obesity worldwide seems to be influenced by external factors independent of eating habits, physical exercise, or genetic characteristics. There may be a number of such factors, but one hypothesis is that there is person-to-person transmission, causing an epidemic effect, as occurs with infectious diseases. In animal models, experimental infection with human adenovirus-36 (Adv36) causes obesity. Humans cannot be experimentally infected, but a number of studies found a correlation of positive serology for Adv36 with overweight/obesity in humans. In vitro studies have shown that Adv36 accelerates the differentiation and proliferation of preadipocytes into adipocytes and increases their lipid concentration. Another viral mechanism involved is the activation of a noninsulin-dependent process that increases glucose uptake, mainly in adipose tissue and muscle. The increased glucose, coupled with increased lipogenesis due to increased fatty acid synthase and the action of peroxisome proliferator-activated receptor gamma (PPAR-gamma) in stimulating adipocyte differentiation from adult stem cells enhances fat accumulation within the adipocytes. In studies conducted to date, the Adv36 E4 open reading frame 1 gene (E4orf1), which activates the glucose transporter protein isoform 4 (GLUT4) and glucose transporter protein isoform 1 (GLUT1) glucose transporters, appears to play a major role in the virus adipogenesis. The aim of this study was to review the pathophysiology of obesity and the role of Adv36.


Subject(s)
Adenovirus Infections, Human/physiopathology , Adenovirus Infections, Human/virology , Adenoviruses, Human/physiology , Obesity/physiopathology , Obesity/virology , Adenovirus Infections, Human/complications , Adenovirus Infections, Human/etiology , Adipocytes/physiology , Adipogenesis , Adipose Tissue/metabolism , Animals , Glucose/metabolism , Glucose Transporter Type 1/metabolism , Glucose Transporter Type 4/metabolism , Humans , Lipid Metabolism , PPAR gamma/metabolism
12.
Sci Total Environ ; 764: 142805, 2021 Apr 10.
Article in English | MEDLINE | ID: mdl-33082048

ABSTRACT

Volatile organic compounds (VOCs) emitted from coal-fired flue gas of thermal power plants have reached unprecedented levels due to lack of understanding of reaction mechanisms under industrial settings. Herein, inhibition mechanisms for catalytic oxidation of o-xylene in simulated coal-fired flue gas are elucidated with in-situ and ex-situ spectroscopic techniques considering the presence of impurity components (NO, NH3, SO2, H2O). MnCe oxide catalysts prepared at Mn: Ce mass ratios of 6:4 are demonstrated to promote 87% o-xylene oxidation at 250 °C under gas hourly space velocities of 60,000 h-1. Reaction intermediates on the catalyst surface are revealed to be o-benzoquinones, benzoates, and formate and they were stably formed under O2/N2 atmospheres. When either NO or NH3 was introduced into the simulated flue gas, the formed species shifted toward formate in minutes, which indicated that changes in catalyst surface chemistry are directly related to impurity components. Presence of NH3 in the simulated flue gas inhibited o-xylene oxidation by reducing Mn and lowering Brønsted acidity of the catalyst. Impurity components associated with pollutant removal processes (Hg0 oxidation and selective catalytic reduction of NO) lowered o-xylene removal efficiency. Presence of o-xylene in the flue gas had little effect on the efficiency of pollutant removal processes. Layered catalytic beds located downstream from Hg0/NO pollutant removal processes are proposed to lower VOC emissions from coal-fired flue gases of thermal power plants in industrial settings.

13.
Appl Radiat Isot ; 168: 109465, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33218917

ABSTRACT

Hydrothermal pretreatment of soils (Andosols) from Ibaraki prefecture (Japan) was used to improve methods for monitoring radioactive Sr and U. Calcined samples were pretreated with subcritical or supercritical water (SCW) followed by extraction with 0.5 M HNO3 solutions. With SCW pretreatment, recoveries of Sr and U were 70% and 40%, respectively. Experimental recoveries obtained can be described by a linear relationship in water density. The proposed method is robust and can lower environmental burden of routine analytical protocols.


Subject(s)
Soil Pollutants, Radioactive/analysis , Water Pollutants, Radioactive/analysis , Radiation Monitoring/methods , Strontium Radioisotopes/analysis , Uranium/analysis
14.
Elife ; 92020 12 28.
Article in English | MEDLINE | ID: mdl-33370234

ABSTRACT

Fibroblasts play an essential role in organogenesis and the integrity of tissue architecture and function. Growth in most solid tumors is dependent upon remodeling 'stroma', composed of cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM), which plays a critical role in tumor initiation, progression, metastasis, and therapeutic resistance. Recent studies have clearly established that the potent immunosuppressive activity of stroma is a major mechanism by which stroma can promote tumor progression and confer resistance to immune-based therapies. Herein, we review recent advances in identifying the stroma-dependent mechanisms that regulate cancer-associated inflammation and antitumor immunity, in particular, the interactions between fibroblasts and immune cells. We also review the potential mechanisms by which stroma can confer resistance to immune-based therapies for solid tumors and current advancements in stroma-targeted therapies.


Subject(s)
Cancer-Associated Fibroblasts/immunology , Immunotherapy , Tumor Escape/immunology , Tumor Microenvironment/immunology , Animals , Humans
15.
J Appl Physiol (1985) ; 129(3): 522-532, 2020 09 01.
Article in English | MEDLINE | ID: mdl-32730176

ABSTRACT

Efforts to better understand cardiorespiratory health are relevant for the future development of optimized physical activity programs. We aimed to explore the impact of the signal quality on the expected associations between the ability of the aerobic system in supplying energy as fast as possible during moderate exercise transitions with its maximum capacity to supply energy during maximal exertion. It was hypothesized that a slower aerobic system response during moderate exercise transitions is associated with a lower maximal aerobic power; however, this relationship relies on the quality of the oxygen uptake data set. Forty-three apparently healthy participants performed a moderate constant work rate (CWR) followed by a pseudorandom binary sequence (PRBS) exercise protocol on a cycle ergometer. Participants also performed a maximum incremental cardiopulmonary exercise testing (CPET). The maximal aerobic power was evaluated by the peak oxygen uptake during the CPET, and the aerobic fitness was estimated from different approaches for oxygen uptake dynamics analysis during the CWR and PRBS protocols at different levels of signal-to-noise ratio. The product moment correlation coefficient was used to evaluate the correlation level between variables. Aerobic fitness was correlated with maximum aerobic power, but this correlation increased as a function of the signal-to-noise ratio. Aerobic fitness is related to maximal aerobic power; however, this association appeared to be highly dependent on the data quality and analysis for aerobic fitness evaluation. Our results show that simpler moderate exercise protocols might be as good as maximal exertion exercise protocols to obtain indexes related to cardiorespiratory health.NEW & NOTEWORTHY Optimized methods for cardiorespiratory health evaluation are of great interest for public health. Moderate exercise protocols might be as good as maximum exertion exercise protocols to evaluate cardiorespiratory health. Pseudorandom or constant workload moderate exercise can be used to evaluate cardiorespiratory health.


Subject(s)
Exercise , Oxygen Consumption , Exercise Test , Humans , Physical Fitness , Signal-To-Noise Ratio
16.
Sci Total Environ ; 719: 137534, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-32135324

ABSTRACT

Transfer hydrogenation is highly effective for dechlorinating priority organic pollutants in wastewater. Lindane could be completely dechlorinated at room temperature and atmospheric pressure via transfer hydrogenation, in which Pd (3.1 wt%) supported on chitosan-derived porous carbon (3.1Pd@A600) and formic acid (FA) were used as catalyst and hydrogen source, respectively. Favorable catalytic activity of 3.1Pd@A600 is attributed to pyridinic N of the support that allowed Pd nanoparticles to be well-dispersed in the solid and to pyridinic N-Pd interactions that enhanced FA decomposition over that observed for commercial carbon supported Pd catalyst (5Pd@AC). In the reaction system containing 3.1Pd@A600 and FA, 99.7% lindane conversion and 100% dechlorination efficiency could be achieved at 25 °C and atmospheric pressure within 60 min. Benzene and cyclohexane were identified as end-products of lindane dechlorination. The transfer hydrogenation strategy developed in this study has wide application to chlorinated organic pollutants contained in actual waste streams.

17.
Article in English | WPRIM (Western Pacific) | ID: wpr-881313
18.
Article in English | MEDLINE | ID: mdl-31440475

ABSTRACT

Clearance of intracellular pathogens, such as Leishmania (L.) major, depends on an immune response with well-regulated cytokine signaling. Here we describe a pathogen-mediated mechanism of evading CXCL10, a chemokine with diverse antimicrobial functions, including T cell recruitment. Infection with L. major in a human monocyte cell line induced robust CXCL10 transcription without increasing extracellular CXCL10 protein concentrations. We found that this transcriptionally independent suppression of CXCL10 is mediated by the virulence factor and protease, glycoprotein-63 (gp63). Specifically, GP63 cleaves CXCL10 after amino acid A81 at the base of a C-terminal alpha-helix. Cytokine cleavage by GP63 demonstrated specificity, as GP63 cleaved CXCL10 and its homologs, which all bind the CXCR3 receptor, but not distantly related chemokines, such as CXCL8 and CCL22. Further characterization demonstrated that CXCL10 cleavage activity by GP63 was produced by both extracellular promastigotes and intracellular amastigotes. Crucially, CXCL10 cleavage impaired T cell chemotaxis in vitro, indicating that cleaved CXCL10 cannot signal through CXCR3. Ultimately, we propose CXCL10 suppression is a convergent mechanism of immune evasion, as Salmonella enterica and Chlamydia trachomatis also suppress CXCL10. This commonality suggests that counteracting CXCL10 suppression may provide a generalizable therapeutic strategy against intracellular pathogens. Importance: Leishmaniasis, an infectious disease that annually affects over one million people, is caused by intracellular parasites that have evolved to evade the host's attempts to eliminate the parasite. Cutaneous leishmaniasis results in disfiguring skin lesions if the host immune system does not appropriately respond to infection. A family of molecules called chemokines coordinate recruitment of the immune cells required to eliminate infection. Here, we demonstrate a novel mechanism that Leishmania (L.) spp. employ to suppress host chemokines: a Leishmania-encoded protease cleaves chemokines known to recruit T cells that fight off infection. We observe that other common human intracellular pathogens, including Chlamydia trachomatis and Salmonella enterica, reduce levels of the same chemokines, suggesting a strong selective pressure to avoid this component of the immune response. Our study provides new insights into how intracellular pathogens interact with the host immune response to enhance pathogen survival.


Subject(s)
Chemokine CXCL10/antagonists & inhibitors , Immune Evasion , Immunologic Factors/antagonists & inhibitors , Leishmania major/growth & development , Leishmania major/immunology , Monocytes/immunology , Monocytes/parasitology , Cell Line , Chlamydia trachomatis/growth & development , Chlamydia trachomatis/immunology , Humans , Immunosuppression Therapy , Metalloendopeptidases/metabolism , Protein Biosynthesis , Proteolysis , Salmonella enterica/growth & development , Salmonella enterica/immunology , T-Lymphocytes/immunology , Transcription, Genetic
19.
Methods Cell Biol ; 152: 41-67, 2019.
Article in English | MEDLINE | ID: mdl-31326026

ABSTRACT

The Automated Tape-Collecting Ultramicrotome (ATUM) is a tape-reeling device that is placed in a water-filled diamond knife boat to collect serial sections as they are cut by a conventional ultramicrotome. The ATUM can collect thousands of sections of many different shapes and sizes, which are subsequently imaged by a scanning electron microscope. This method has been used for large-scale connectomics projects of mouse brain, and is well suited for other smaller-scale studies of tissues, cells, and organisms. Here, we describe basic procedures for preparing a block for ATUM sectioning, handling of the ATUM, tape preparation, post-treatment of sections, and considerations for mapping, imaging, and aligning the serial sections.


Subject(s)
Microscopy, Electron, Scanning/methods , Microtomy/methods , Animals , Brain/physiology , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Mice
20.
Biomicrofluidics ; 13(1): 014105, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30867876

ABSTRACT

The primary cilium plays an important role in mechanosensation in mammalian cells. To understand mechanosensation in the primary cilium, we combined a microfluidic device with super-resolution microscopy to study the primary cilium phenotypes. The microfluidic system enabled the precise control of the flow shear within a well-confined cell-culture environment. In addition, in situ cilia fixation was possible by switching from the culture medium to the fixation buffer instantaneously, which preserved the real-time cilium phenotype under the flow shear. After fixation, multiple cilium-specific proteins were immunostained to quantify the cilia bending behavior. We found that >50% of the primary cilia of mouse inner medullary collecting duct cells were highly aligned with the direction of flow under 11 Pa shear stress. Finally, we used super-resolution microscopy to observe the redistribution of two major cilium-specific proteins under flow shear, acetylated alpha-tubulin, and intraflagellar transport protein 88. To the best of our knowledge, this is the first platform to combine a microfluidic device with super-resolution microscopy to enable flow stimulation and in situ fixation for the observation of ciliary protein. This system can potentially be applied to the future development of a stimulation-enabled organ-on-a-chip to observe the intercellular signaling of primary cilia or for the analysis of disease mechanisms associated with ciliary mutations at the organ level.

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