Effect of lactoferrin protein on red blood cells and macrophages: mechanism of parasite-host interaction

BACKGROUND: Lactoferrin is a natural multifunctional protein known to have antitumor, antimicrobial, and anti-inflammatory activity. Apart from its antimicrobial effects, lactoferrin is known to boost the immune response by enhancing antioxidants. Lactoferrin exists in various forms depending on its iron saturation. The present study was done to observe the effect of lactoferrin, isolated from bovine and buffalo colostrum, on red blood cells (RBCs) and macrophages (human monocytic cell line-derived macrophages THP1 cells). METHODS: Lactoferrin obtained from both species and in different iron saturation forms were used in the present study, and treatment of host cells were given with different forms of lactoferrin at different concentrations. These treated host cells were used for various studies, including morphometric analysis, viability by MTT assay, survivin gene expression, production of reactive oxygen species, phagocytic properties, invasion assay, and Toll-like receptor-4, Toll-like receptor-9, and MDR1 expression, to investigate the interaction between lactoferrin and host cells and the possible mechanism of action with regard to parasitic infections. RESULTS: The mechanism of interaction between host cells and lactoferrin have shown various aspects of gene expression and cellular activity depending on the degree of iron saturation of lactoferrin. A significant increase (P<0.05) in production of reactive oxygen species, phagocytic activity, and Toll-like receptor expression was observed in host cells incubated with iron-saturated lactoferrin when compared with an untreated control group. However, there was no significant (P>0.05) change in percentage viability in the different groups of host cells treated, and no downregulation of survivin gene expression was found at 48 hours post-incubation. Upregulation of the Toll-like receptor and downregulation of the P-gp gene confirmed the immunomodulatory potential of lactoferrin protein. CONCLUSION: The present study details the interaction between lactoferrin and parasite host cells, ie, RBCs and macrophages, using various cellular processes and expression studies. The study reveals the possible mechanism of action against various intracellular pathogens such as Toxoplasma, Plasmodium, Leishmania, Trypanosoma, and Mycobacterium. The presence of iron in lactoferrin plays an important role in enhancing the various activities taking place inside these cells. This work provides a lot of information about targeting lactoferrin against many parasitic infections which can rule out the exact pathways for inhibition of diseases caused by intracellular microbes mainly targeting RBCs and macrophages for their survival. Therefore, this initial study can serve as a baseline for further evaluation of the mechanism of action of lactoferrin against parasitic diseases, which is not fully understood to date

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

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DFT investigation on thermochemical analyses of conversion of xylose to linear alkanes in aqueous phase

Xylose is an integral part of hemicellulose fraction of lignocellulosic biomass. Its abundance in the lignocellulose makes it a desirable component for converting into various value-added compounds. In this study, conversion of xylose to four linear alkanes has been discussed by five different schemes including their thermochemistry under the framework of density functional theory. Main products are butane, pentane, octane and tridecane whereas the intermediate products include furfural, tetrahydrofuran, pentane-1,5-diol, etc. The simulations have been performed at B3LYP/6–31 + g(d,p) and M06-2X/6–31 + g(d,p) level of theories in aqueous phase using SMD solvation model. Thermochemical parameters (ΔG, ΔH and Keq) are obtained at a wide range of temperature, i.e. 298–698 K. Single point energy change (ΔE) of all the conversion steps has also been calculated at M05-2X/6–311++g(3df,2p) level of theory in the aqueous phase. It is observed that temperature plays a vital role in the formation of products. At high temperature, only scheme RS 1 (i.e. xylose to butane) can proceed to produce butane. The absolute difference between two functionals, B3LYP and M06-2X, was found to be small (10 kcal/mol) was observed between the two functionals making higher accuracy method more suitable for them. For all other reactions, use of M06-2X can be preferred

Binding of phenolic model compounds with noble metal doped graphene sheets

Presence of large number of oxygenates in raw bio-oil restrict its application as transportation fuel. Therefore, there is a strong necessity of finding a viable catalyst for upgrading raw bio-oil to transportation fuel level. In this study, palladium- and platinum- doped graphene sheets are examined theoretically for possible interactions of oxygenates such as guaiacol, phenol, anisole, vanillin, and salicylaldehyde on to metal doped graphene catalyst surfaces to understand preliminary adsorption mechanisms. For this purpose, B3PW91 functional of density functional theory (DFT) has been utilized. Adsorption kinetics, for instance, adsorption free energy, adsorption enthalpy, and equilibrium rate constant at a fixed pressure of 1 atm but over a wide range of temperature (400–800 K) are reported. Briefly results indicate that binding of both metals at vacant site of graphene sheet is found to be high energy releasing process and excellently agree with their contemporary literature results. The interaction of hydroxyl group of salicylaldehyde with Pd-doped graphene (PdGr) surface is most favourable configuration, whereas, Pt-doped graphene (PtGr) surface exhibited superior adsorption stability through phenyl ring. Binding of guaiacol, phenol, and anisole are energetically most favourable by phenyl ring interaction over each surface. Vanillin interacts strongly by oxygen atom of formyl group over PtGr surface. Further the values of adsorption kinetic parameters are very high for all model species; however, temperature increment deteriorates them. Finally, for each adsorption configuration of all model species over both catalyst surfaces, ln(Keq) vs. 1/T relation is proposed

Elucidation of novel mechanisms to produce value-added chemicals from vapour phase conversion of ferulic acid

Ferulic acid is one of high molecular weight phenolic compounds of raw bio-oil produced from thermochemical conversion of lignocellulosic biomass. Due to its unique chemical fragmentation, it can be converted into various specialty chemicals such as methyl-2-phenylacetate, cinnamic acid, methyl-benzoate, methyl- and ethyl-cinnamate and others. In this numerical study, ferulic acid is converted into aforementioned specialty chemicals with analyses of their potential energy surfaces, activation energies, and thermodynamic feasibilities by density functional theory using B3LYP functional. The selection of B3LYP functional is also demonstrated by comparing single point energy of a couple of reaction pathways with those obtained by M05-2X functional. In the thermochemical analyses, all reaction schemes are subjected at a wide range of temperature conditions varying from 598 to 898 K. The productions of phenol and cinnamic acid required overall activation energy of only 5 kcal/mol due to the same rate-determining step. Further conversion of phenol into the end product methyl-benzoate is not advantageous because of high-energy demands and positive values of reaction free energy and reaction enthalpy at each temperature. According to thermochemical analysis, the production of methyl-2-phenylacetate is highly spontaneous even at the lower temperature; however, at elevated temperature conditions, its spontaneity decreases and exothermicity improves further

Computational Screening of Doped Graphene Electrodes for Alkaline CO2 Reduction

The electrocatalytic CO2 reduction reaction (CO2RR) is considered as one of the most promising approaches to synthesizing carbonaceous fuels and chemicals without utilizing fossil resources. However, current technologies are still in the early phase focusing primarily on identifying optimal electrode materials and reaction conditions. Doped graphene-based materials are among the best CO2RR electrocatalysts and in the present work we have performed a computational screening study to identify suitable graphene catalysts for CO2RR to CO under alkaline conditions. Several types of modified-graphene frameworks doped with metallic and non-metallic elements were considered. After establishing thermodynamically stable electrodes, the electrochemical CO2RR to CO is studied in the alkaline media. Both concerted proton-coupled electron transfer (PCET) and decoupled proton and electron transfer (ETPT) mechanisms were considered by developing and using a generalization of the computational hydrogen electrode approach. It is established that the CO2 electrosorption and associated charge transfer along the ETPT pathway are of utmost importance and significantly impact the electrochemical thermodynamics of CO2RR. Our study suggests an exceptional performance of metal-doped nitrogen-coordinated graphene electrodes, especially 3N-coordinated graphene electrodes