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  1. Article ; Online: Long Vibrational Lifetime R-Selenocyanate Probes for Ultrafast Infrared Spectroscopy: Properties and Synthesis.

    Fica-Contreras, Sebastian M / Daniels, Robert / Yassin, Omer / Hoffman, David J / Pan, Junkun / Sotzing, Gregory / Fayer, Michael D

    The journal of physical chemistry. B

    2021  Volume 125, Issue 31, Page(s) 8907–8918

    Abstract: Ultrafast infrared vibrational spectroscopy is widely used for the investigation of dynamics in systems from water to model membranes. Because the experimental observation window is limited to a few times the probe's vibrational lifetime, a frequent ... ...

    Abstract Ultrafast infrared vibrational spectroscopy is widely used for the investigation of dynamics in systems from water to model membranes. Because the experimental observation window is limited to a few times the probe's vibrational lifetime, a frequent obstacle for the measurement of a broad time range is short molecular vibrational lifetimes (typically a few to tens of picoseconds). Five new long-lifetime aromatic selenocyanate vibrational probes have been synthesized and their vibrational properties characterized. These probes are compared to commercial phenyl selenocyanate. The vibrational lifetimes range between ∼400 and 500 ps in complex solvents, which are some of the longest room-temperature vibrational lifetimes reported to date. In contrast to vibrations that are long-lived in simple solvents such as CCl
    MeSH term(s) Cyanates ; Selenium Compounds ; Spectrophotometry, Infrared ; Vibration
    Chemical Substances Cyanates ; Selenium Compounds ; selenocyanic acid (5749-48-4)
    Language English
    Publishing date 2021-08-02
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.1c04939
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: PCSK9-D374Y mediated LDL-R degradation can be functionally inhibited by EGF-A and truncated EGF-A peptides: An in vitro study.

    Valenti, Vincenza / Noto, Davide / Giammanco, Antonina / Fayer, Francesca / Spina, Rossella / Altieri, Grazia I / Ingrassia, Valeria / Scrimali, Chiara / Barbagallo, Carlo M / Brucato, Federica / Misiano, Gabriella / Cefalù, Angelo B / Averna, Maurizio R

    Atherosclerosis

    2019  Volume 292, Page(s) 209–214

    Abstract: Background and aims: Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low density lipoprotein receptor (LDLR) through the LDLR epidermal growth factor-like repeat A (EGF-A) domain and induces receptor internalization and degradation. PCSK9 ...

    Abstract Background and aims: Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low density lipoprotein receptor (LDLR) through the LDLR epidermal growth factor-like repeat A (EGF-A) domain and induces receptor internalization and degradation. PCSK9 has emerged as a novel therapeutic target for hypercholesterolemia. Clinical studies with PCSK9 inhibiting antibodies have demonstrated strong LDL-c lowering effects, but other therapeutic approaches using small molecule inhibitors for targeting PCSK9 functions may offer supplementary therapeutic options. The aim of our study was to evaluate the effect of synthetic EGF-A analogs on mutated (D374Y) PCSK9-D374Y mediated LDLR degradation in vitro.
    Methods: Huh7 human hepatoma cells were transiently transfected to overexpress the gain-of-function D374Y PCSK9 mutation, which has been associated with severe hypercholesterolemia in humans.
    Results: Transient transfection of cells with PCSK9-D374Y expression vector very effectively enhanced degradation of mature LDLR in Huh7. Treatment with both EGF-A and EGF-A truncated peptides inhibited this effect and showed increased LDLR protein in Huh7 cells transfected with PCSK9-D374Y in a clear concentration dependent manner. Huh7 transfected cells treated with increasing concentration of EGF-A analogs also showed an increase internalization of labeled Dil-LDL.
    Conclusions: The result of our study shows that EGF-A analogs are able to effectively hamper the enhanced degradation of LDLR in liver cells expressing PCSK9-D374Y.
    MeSH term(s) Cells, Cultured ; Epidermal Growth Factor/pharmacology ; Humans ; Mutation ; Proprotein Convertase 9/antagonists & inhibitors ; Proprotein Convertase 9/genetics ; Proprotein Convertase 9/physiology ; Receptors, LDL/metabolism
    Chemical Substances LDLR protein, human ; Receptors, LDL ; Epidermal Growth Factor (62229-50-9) ; PCSK9 protein, human (EC 3.4.21.-) ; Proprotein Convertase 9 (EC 3.4.21.-)
    Language English
    Publishing date 2019-09-24
    Publishing country Ireland
    Document type Journal Article
    ZDB-ID 80061-2
    ISSN 1879-1484 ; 0021-9150
    ISSN (online) 1879-1484
    ISSN 0021-9150
    DOI 10.1016/j.atherosclerosis.2019.09.009
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Long Vibrational Lifetime R-Selenocyanate Probes for Ultrafast Infrared Spectroscopy: Properties and Synthesis

    Fica-Contreras, Sebastian M. / Daniels, Robert / Yassin, Omer / Hoffman, David J. / Pan, Junkun / Sotzing, Gregory / Fayer, Michael D.

    Journal of physical chemistry. 2021 Aug. 02, v. 125, no. 31

    2021  

    Abstract: Ultrafast infrared vibrational spectroscopy is widely used for the investigation of dynamics in systems from water to model membranes. Because the experimental observation window is limited to a few times the probe’s vibrational lifetime, a frequent ... ...

    Abstract Ultrafast infrared vibrational spectroscopy is widely used for the investigation of dynamics in systems from water to model membranes. Because the experimental observation window is limited to a few times the probe’s vibrational lifetime, a frequent obstacle for the measurement of a broad time range is short molecular vibrational lifetimes (typically a few to tens of picoseconds). Five new long-lifetime aromatic selenocyanate vibrational probes have been synthesized and their vibrational properties characterized. These probes are compared to commercial phenyl selenocyanate. The vibrational lifetimes range between ∼400 and 500 ps in complex solvents, which are some of the longest room-temperature vibrational lifetimes reported to date. In contrast to vibrations that are long-lived in simple solvents such as CCl₄, but become much shorter in complex solvents, the probes discussed here have ∼400 ps lifetimes in complex solvents and even longer in simple solvents. One of them has a remarkable lifetime of 1235 ps in CCl₄. These probes have a range of molecular sizes and geometries that can make them useful for placement into different complex materials due to steric reasons, and some of them have functionalities that enable their synthetic incorporation into larger molecules, such as industrial polymers. We investigated the effect of a range of electron-donating and electron-withdrawing para-substituents on the vibrational properties of the CN stretch. The probes have a solvent-independent linear relationship to the Hammett substituent parameter when evaluated with respect to the CN vibrational frequency and the ipso ¹³C NMR chemical shift.
    Keywords ambient temperature ; infrared spectroscopy ; physical chemistry
    Language English
    Dates of publication 2021-0802
    Size p. 8907-8918.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5207
    DOI 10.1021/acs.jpcb.1c04939
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Ion/Water Network Structural Dynamics in Highly Concentrated Lithium Chloride and Lithium Bromide Solutions Probed with Ultrafast Infrared Spectroscopy.

    Roget, Sean A / Heck, Tristan R / Carter-Fenk, Kimberly A / Fayer, Michael D

    The journal of physical chemistry. B

    2023  Volume 127, Issue 20, Page(s) 4532–4543

    Abstract: The structural dynamics of highly concentrated LiCl and LiBr aqueous solutions were observed from 1-4 to 1-16 water molecules per ion pair using ultrafast polarization-selective pump-probe (PSPP) experiments on the OD stretch of dilute HOD. At these high ...

    Abstract The structural dynamics of highly concentrated LiCl and LiBr aqueous solutions were observed from 1-4 to 1-16 water molecules per ion pair using ultrafast polarization-selective pump-probe (PSPP) experiments on the OD stretch of dilute HOD. At these high salt concentrations, an extended ion/water network exists with complex structural dynamics. Population decays from PSPP experiments highlight two distinct water components. From the frequency-dependent amplitudes of the decays, the spectra of hydroxyls bound to halides and to water oxygens are obtained, which are not observable in the FT-IR spectra. PSPP experiments also measure frequency-dependent water orientational relaxation. At short times, wobbling dynamics within a restricted angular cone occurs. At high concentrations, the cone angles are dependent on frequency (hydrogen bond strength), but at higher water concentrations (>10 waters per ion pair), there is no frequency dependence. The average cone angle increases as the ion concentration decreases. The slow time constant for complete HOD orientational relaxation is independent of concentration but slower in LiCl than in LiBr. Comparison to structural MD simulations of LiCl from the literature indicates that the loss of the cone angle wavelength dependence and the increase in the cone angles as the concentration decreases occur as the prevalence of large ion/water clusters gives way to contact ion pairs.
    Language English
    Publishing date 2023-05-12
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.2c08792
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Directional Stepping Model for Yeast Dynein: Longitudinal- and Side-Step Distributions.

    Fayer, Itay / Granek, Rony

    Biophysical journal

    2019  Volume 117, Issue 10, Page(s) 1892–1899

    Abstract: Motor proteins are biological machines that convert chemical energy stored in ATP to mechanical work. Kinesin and dynein are microtubule (MT)-associated motor proteins that, among other functions, facilitate intracellular transport. Here, we focus on ... ...

    Abstract Motor proteins are biological machines that convert chemical energy stored in ATP to mechanical work. Kinesin and dynein are microtubule (MT)-associated motor proteins that, among other functions, facilitate intracellular transport. Here, we focus on dynein motility. We deduce the directional step distribution of yeast dynein motor protein on the MT surface by combing intrinsic features of the dynein and MTs. These include the probability distribution of the separation vector between the two microtubule-binding domains, the angular probability distribution of a single microtubule-binding domain translation, the existence of an MT seam defect, MT-binding sites, and theoretical extension that accounts for a load force on the motor. Our predictions are in excellent accord with the measured longitudinal step size distributions at various load forces. Moreover, we predict the side-step distribution and its dependence on longitudinal load forces, which shows a few surprising features. First, the distribution is broad. Second, in the absence of load, we find a small right-handed bias. Third, the side-step bias is susceptible to the longitudinal load force; it vanishes at a load equal to the motor stalling force and changes to a left-hand bias above that value. Fourth, our results are sensitive to the ability of the motor to explore the seam several times during its walk. Although available measurements of side-way distribution are limited, our findings are amenable to experimental check and, moreover, suggest a diversity of results depending on whether the MT seam is viable to motor sampling.
    MeSH term(s) Adenosine Triphosphate/metabolism ; Binding Sites ; Biomechanical Phenomena ; Dyneins/chemistry ; Dyneins/metabolism ; Models, Biological ; Probability ; Protein Binding ; Protein Domains ; Saccharomyces cerevisiae/metabolism ; Temperature
    Chemical Substances Adenosine Triphosphate (8L70Q75FXE) ; Dyneins (EC 3.6.4.2)
    Language English
    Publishing date 2019-10-10
    Publishing country United States
    Document type Journal Article
    ZDB-ID 218078-9
    ISSN 1542-0086 ; 0006-3495
    ISSN (online) 1542-0086
    ISSN 0006-3495
    DOI 10.1016/j.bpj.2019.09.043
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Dynamics of Water Molecules and Ions in Concentrated Lithium Chloride Solutions Probed with Ultrafast 2D IR Spectroscopy.

    Yuan, Rongfeng / Fayer, Michael D

    The journal of physical chemistry. B

    2019  Volume 123, Issue 35, Page(s) 7628–7639

    Abstract: Water and ion dynamics in concentrated LiCl solutions were studied using ultrafast 2D IR spectroscopy with the methyl thiocyanate (MeSCN) CN stretch as the vibrational probe. The IR absorption spectrum of MeSCN has two peaks, one peak for water ... ...

    Abstract Water and ion dynamics in concentrated LiCl solutions were studied using ultrafast 2D IR spectroscopy with the methyl thiocyanate (MeSCN) CN stretch as the vibrational probe. The IR absorption spectrum of MeSCN has two peaks, one peak for water associated with the nitrogen lone pair of MeSCN (W) and the other peak corresponding to Li
    Language English
    Publishing date 2019-08-22
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.9b06038
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Comparison of nonabsorbable markers Poly R-478 and [14C]PEG-4,000 for use in developmental absorption studies.

    Stahl, G E / Fayer, J C / Ling, S C / Watkins, J B

    Journal of pediatric gastroenterology and nutrition

    1991  Volume 12, Issue 4, Page(s) 485–493

    Abstract: To determine the utility of Poly R-478, a stable, polymeric dye (MW, 40,000), as a nonabsorbable ... of Poly R-478 from biological samples is simple and rapid compared to other nonradioactive nonabsorbable ... markers. In 40-day-old rats simultaneously given Poly R-478 and [14C]PEG, total recoveries were similar ...

    Abstract To determine the utility of Poly R-478, a stable, polymeric dye (MW, 40,000), as a nonabsorbable marker for studies in the developing small intestine, it was validated by comparison to carbon 14-labeled polyethylene glycol, MW 4,000 [( 14C]PEG-4,000) in rats from 14 to 40 days of age. The recovery and quantification of Poly R-478 from biological samples is simple and rapid compared to other nonradioactive nonabsorbable markers. In 40-day-old rats simultaneously given Poly R-478 and [14C]PEG, total recoveries were similar, the percentages of the Poly R-478 dose and the [14C]PEG dose recovered per segment were identical, and taurocholate absorption rates calculated using each marker were comparable. Recovery of Poly R-478 from flushed intestinal segments, determined by a one-step extraction, was equivalent to that of [14C]PEG in 40-day-old rats (96.5 +/- 3.7% versus 102.7 +/- 10.1%; NS) but was superior to that of [14C]PEG in 21-day-old rats (98.0 +/- 6.2% versus 63.4 +/- 5.5%; p less than 0.001) and 14-day-old rats (97.8 +/- 6.7% versus 56.7 +/- 12.6%; p less than 0.001). Within each age group, the distribution of Poly R-478 within the intestine was similar to that of [14C]PEG. In addition, total taurocholate absorption in the presence of Poly R-478 was comparable to that in the presence of [14C]PEG. Complete recovery of Poly R-478 from a suspension of liver particles and from mixtures with two commercial infant formulas was demonstrated in vitro, suggesting that Poly R-478 may be used when foods are present in the intestine.(ABSTRACT TRUNCATED AT 250 WORDS)
    MeSH term(s) Analysis of Variance ; Animals ; Anthraquinones ; Carbon Radioisotopes ; Coloring Agents ; Food ; Intestinal Absorption/physiology ; Intestines/growth & development ; Male ; Polyethylene Glycols ; Polymers ; Rats ; Rats, Inbred Strains ; Regression Analysis ; Taurocholic Acid/metabolism
    Chemical Substances Anthraquinones ; Carbon Radioisotopes ; Coloring Agents ; Polymers ; Polyethylene Glycols (3WJQ0SDW1A) ; Taurocholic Acid (5E090O0G3Z) ; poly R-478 (68816-54-6)
    Language English
    Publishing date 1991-05
    Publishing country United States
    Document type Comparative Study ; Journal Article
    ZDB-ID 603201-1
    ISSN 1536-4801 ; 0277-2116
    ISSN (online) 1536-4801
    ISSN 0277-2116
    DOI 10.1097/00005176-199105000-00013
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Introduction of Lihua Xiao, recipient of the Henry Baldwin Ward Medal for 2012.

    Fayer, Ronald

    The Journal of parasitology

    2012  Volume 98, Issue 6, Page(s) 1071–1072

    MeSH term(s) Awards and Prizes ; History, 20th Century ; History, 21st Century ; Parasitology/history ; Societies, Scientific ; United States
    Language English
    Publishing date 2012-12
    Publishing country United States
    Document type Biography ; Historical Article ; Journal Article
    ZDB-ID 300870-8
    ISSN 1937-2345 ; 0022-3395
    ISSN (online) 1937-2345
    ISSN 0022-3395
    DOI 10.1645/12-56.1
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Taxonomy and molecular epidemiology of Cryptosporidium and Giardia - a 50 year perspective (1971-2021).

    Ryan, Una M / Feng, Yaoyu / Fayer, Ronald / Xiao, Lihua

    International journal for parasitology

    2021  Volume 51, Issue 13-14, Page(s) 1099–1119

    Abstract: The protozoan parasites Cryptosporidium and Giardia are significant causes of diarrhoea worldwide and are responsible for numerous waterborne and foodborne outbreaks of diseases. Over the last 50 years, the development of improved detection and typing ... ...

    Abstract The protozoan parasites Cryptosporidium and Giardia are significant causes of diarrhoea worldwide and are responsible for numerous waterborne and foodborne outbreaks of diseases. Over the last 50 years, the development of improved detection and typing tools has facilitated the expanding range of named species. Currently at least 44 Cryptosporidium spp. and >120 genotypes, and nine Giardia spp., are recognised. Many of these Cryptosporidium genotypes will likely be described as species in the future. The phylogenetic placement of Cryptosporidium at the genus level is still unclear and further research is required to better understand its evolutionary origins. Zoonotic transmission has long been known to play an important role in the epidemiology of cryptosporidiosis and giardiasis, and the development and application of next generation sequencing tools is providing evidence for this. Comparative whole genome sequencing is also providing key information on the genetic mechanisms for host specificity and human infectivity, and will enable One Health management of these zoonotic parasites in the future.
    MeSH term(s) Cryptosporidiosis/epidemiology ; Cryptosporidiosis/parasitology ; Cryptosporidium/genetics ; Feces/parasitology ; Genotype ; Giardia/genetics ; Giardiasis/epidemiology ; Giardiasis/parasitology ; Humans ; Molecular Epidemiology ; Phylogeny
    Language English
    Publishing date 2021-10-26
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 120518-3
    ISSN 1879-0135 ; 0020-7519
    ISSN (online) 1879-0135
    ISSN 0020-7519
    DOI 10.1016/j.ijpara.2021.08.007
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Taxonomy and species delimitation in Cryptosporidium.

    Fayer, Ronald

    Experimental parasitology

    2010  Volume 124, Issue 1, Page(s) 90–97

    Abstract: Amphibians, reptiles, birds and mammals serve as hosts for 19 species of Cryptosporidium. All 19 species have been confirmed by morphological, biological, and molecular data. Fish serve as hosts for three additional species, all of which lack supporting ... ...

    Abstract Amphibians, reptiles, birds and mammals serve as hosts for 19 species of Cryptosporidium. All 19 species have been confirmed by morphological, biological, and molecular data. Fish serve as hosts for three additional species, all of which lack supporting molecular data. In addition to the named species, gene sequence data from more than 40 isolates from various vertebrate hosts are reported in the scientific literature or are listed in GenBank. These isolates lack taxonomic status and are referred to as genotypes based on the host of origin. Undoubtedly, some will eventually be recognized as species. For them to receive taxonomic status sufficient morphological, biological, and molecular data are required and names must comply with the rules of the International Code for Zoological Nomenclature (ICZN). Because the ICZN rules may be interpreted differently by persons proposing names, original names might be improperly assigned, original literature might be overlooked, or new scientific methods might be applicable to determining taxonomic status, the names of species and higher taxa are not immutable. The rapidly evolving taxonomic status of Cryptosporidium sp. reflects these considerations.
    MeSH term(s) Amphibians/parasitology ; Animals ; Bird Diseases/parasitology ; Birds ; Cryptosporidiosis/parasitology ; Cryptosporidiosis/veterinary ; Cryptosporidium/classification ; Cryptosporidium/genetics ; Fish Diseases/parasitology ; Fishes ; Humans ; Mammals/parasitology ; Reptiles/parasitology
    Language English
    Publishing date 2010-01
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 391089-1
    ISSN 1090-2449 ; 0014-4894
    ISSN (online) 1090-2449
    ISSN 0014-4894
    DOI 10.1016/j.exppara.2009.03.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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