Amino sugar phosphate levels in Giardia change during cyst wall formation

The parasite Giardia intestinalis exists as a trophozoite (vegetative) that infects the human small intestine, and a cyst (infective) that is shed in host faeces. Cyst viability in the environment depends upon a protective cyst wall, which consists of proteins and a unique β(1-3) GalNAc homopolymer. UDP-GalNAc, the precursor for this polysaccharide, is synthesized from glucose by an enzyme pathway that involves amino sugar phosphate intermediates. Using a novel method of microanalysis by capillary electrophoresis, the levels of amino sugar phosphate intermediates in trophozoites before encystment, during a period of active encystment and after the peak of encystment were measured. These levels were used to deduce metabolic control of amino sugar phosphates associated with encystment. Levels of amino sugar phosphate intermediates increased during encystment, and then decreased to nearly non-encysting levels. The most pronounced increase was in glucosamine 6-phosphate, which is the first substrate unique in this pathway, and which is the positive effector for the pathway's putative rate-controlling enzyme, UDP-GlcNAc pyrophosphorylase. Moreover, more UDP-GalNAc than UDP-GlcNAc, its direct precursor, was detected at 24 h. It is postulated that the enhanced UDP-GalNAc is a result of enhanced synthesis of UDP-GlcNAc by the pyrophosphorylase, and its preferential conversion to UDP-GalNAc. These results suggest that kinetics of amino sugar phosphate synthesis in encysting Giardia favours the direction that supports cyst wall synthesis. The enzymes involved in synthesis of UDP-GalNAc and its conversion to cyst wall might be potential targets for therapeutic inhibitors of Giardia infection.

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Studies of intermediary metabolism in radish cotyledons. Turnover of photosynthetic products in 14CO2 pulse-chase experiments

Canadian Journal of Botany ◽

10.1139/b70-177 ◽

1970 ◽

Vol 48 (6) ◽

pp. 1191-1198 ◽

Cited By ~ 6

Author(s):

A. Caballero ◽

E. A. Cossins

Keyword(s):

Amino Acids ◽

Organic Acid ◽

Incubation Medium ◽

Growth And Development ◽

Sugar Phosphate ◽

Carbon 14 ◽

Mature Leaves ◽

Photosynthetic Products ◽

Sugar Phosphates ◽

Kinetics Of

Ability of 11-day-old radish cotyledons to carry out photosynthesis has been examined by supplying 14CO2 to cotyledon disks for periods ranging from 30 s to 20 min. Carbon-14 was rapidly incorporated into malate, citrate, sugar phosphates, and a number of amino acids. The kinetics of 14C incorporation suggest that carbon initially enters components of the organic acid and sugar phosphate fraction, being then rapidly transferred to the amino acids and sugars. In pulse-chase experiments, illuminated cotyledon disks were incubated with 14CO2 for 30 min then transferred to air containing 12CO2 for periods up to 240 min with illumination. During such postpulse incubations, considerable losses of 14C occurred from most of the principal compounds labeled during the chase incubation. As these losses were not entirely accounted for by losses of label to the incubation medium they can largely be attributed to metabolic turnover of these compounds. It is concluded that, in general, the photosynthesis of radish cotyledons is similar to that of mature leaves and of physiological significance as a route for synthesis of several important cellular constituents required for seedling growth and development.

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The Influence of Varying Fluorination Patterns on the Thermodynamics and Kinetics of Benzenesulfonamide Binding to Human Carbonic Anhydrase II

Biomolecules ◽

10.3390/biom10040509 ◽

2020 ◽

Vol 10 (4) ◽

pp. 509 ◽

Cited By ~ 2

Author(s):

Steffen Glöckner ◽

Khang Ngo ◽

Björn Wagner ◽

Andreas Heine ◽

Gerhard Klebe

Keyword(s):

Carbonic Anhydrase ◽

Carbonic Anhydrase Ii ◽

The Novel ◽

Binding Modes ◽

X Ray ◽

Structure Activity ◽

Small Set ◽

Novel Method ◽

Human Carbonic Anhydrase ◽

Kinetics Of

The fluorination of lead-like compounds is a common tool in medicinal chemistry to alter molecular properties in various ways and with different goals. We herein present a detailed study of the binding of fluorinated benzenesulfonamides to human Carbonic Anhydrase II by complementing macromolecular X-ray crystallographic observations with thermodynamic and kinetic data collected with the novel method of kinITC. Our findings comprise so far unknown alternative binding modes in the crystalline state for some of the investigated compounds as well as complex thermodynamic and kinetic structure-activity relationships. They suggest that fluorination of the benzenesulfonamide core is especially advantageous in one position with respect to the kinetic signatures of binding and that a higher degree of fluorination does not necessarily provide for a higher affinity or more favorable kinetic binding profiles. Lastly, we propose a relationship between the kinetics of binding and ligand acidity based on a small set of compounds with similar substitution patterns.

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Permeabilization activated reduction in fluorescence: A novel method to measure kinetics of protein interactions with intracellular structures

Cytoskeleton ◽

10.1002/cm.21306 ◽

2016 ◽

Vol 73 (6) ◽

pp. 271-285 ◽

Cited By ~ 3

Author(s):

Pali P. Singh ◽

Jenci L. Hawthorne ◽

Christie A. Davis ◽

Omar A. Quintero

Keyword(s):

Protein Interactions ◽

Novel Method ◽

Kinetics Of

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Kinetic Analysis of the Hydrolysis of Pentose-1-Phosphates Through Apparent Nucleoside Phosphorolysis Equilibrium Shifts

10.26434/chemrxiv.13090244 ◽

2020 ◽

Author(s):

Felix Kaspar ◽

Peter Neubauer ◽

Anke Kurreck

Keyword(s):

Kinetic Analysis ◽

Hydrolysis Kinetics ◽

Equilibrium Thermodynamics ◽

Apparent Increase ◽

Equilibrium Conversion ◽

Sugar Phosphates ◽

Kinetics Of ◽

Hydrolysis Of

<div>Ask what an equilibrium can do for you:</div><div>Hydrolysis of pentose-1-phosphates leads to an apparent increase of the equilibrium conversion in nucleoside phosphorolysis reactions. This information can be leveraged via equilibrium thermodynamics to determine the hydrolysis kinetics of in situ generated sugar phosphates, which are known to be elusive and difficult to quantify.<br></div>

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Bombardment by Reflection - A Novel Method to Prepare High Quality Hydrogenated Amorphous Germanium by Anodic PCVD

MRS Proceedings ◽

10.1557/proc-467-639 ◽

1997 ◽

Vol 467 ◽

Author(s):

Annette Diez ◽

Twlo P. Drüsedau

Keyword(s):

Atomic Hydrogen ◽

Carrier Mobility ◽

Hydrogen Pressure ◽

Amorphous Germanium ◽

Hydrogen Dilution ◽

Novel Method ◽

Hydrogenated Amorphous ◽

Hydrogenated Amorphous Germanium ◽

Kinetics Of

ABSTRACTDeposition of amorphous germanium by anodic PCVD was performed changing the germane/hydrogen dilution ratio from 1/6 to 1/100. Films deposited under high dilution of germane are of a high mechanical density (92.5 % of bulk) and good optoelectronic properties (electrical conductivity at room temperature σ=10−5 (Ω cm)−1, majority carrier mobility-lifetime product at λ=1200 nm ημ=x 10−7 cm2/V). The quality of the films is increased by deposition at increasing pumping speed for hydrogen (lower hydrogen pressure) keeping the other parameters constant. It is suggested that fast atomic hydrogen originating from a backscattering process at the powered electrode bombard the growing film and contribute to the improved quality of the a-Ge:H. Also, the growth kinetics of the films is changed from linear to parabolic dependence on germane flow interchanging deposition from high to low hydrogen pressure. This effect is rationalized in terms of a contribution of energetic atomic hydrogen to the dissociation of germane.

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Kinetics of amino sugar formation from organic residues of different quality

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2012.08.006 ◽

2013 ◽

Vol 57 ◽

pp. 814-821 ◽

Cited By ~ 27

Author(s):

Zhen Bai ◽

Samuel Bodé ◽

Dries Huygens ◽

Xudong Zhang ◽

Pascal Boeckx

Keyword(s):

Amino Sugar ◽

Organic Residues ◽

Kinetics Of

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A comparison of fluorescein diacetate and propidium iodide staining andin vitroexcystation for determiningGiardia intestinaliscyst viability

Parasitology ◽

10.1017/s0031182000059035 ◽

1989 ◽

Vol 99 (3) ◽

pp. 329-331 ◽

Cited By ~ 41

Author(s):

A. L. Smith ◽

H. V. Smith

Keyword(s):

Lower Limit ◽

Propidium Iodide ◽

Giardia Intestinalis ◽

Fluorescein Diacetate ◽

Fluorescent Indicators ◽

Vital Dyes ◽

Propidium Iodide Staining ◽

Cyst Viability

SummaryThe viability of 4 human isolates ofGiardia intestinaliscysts using either the fluorogenic vital dyes fluorescein diacetate (FDA) and propidium iodide (PI) orin vitroexcystation was assessed. Whereas viable cysts, as defined byin vitroexcystation were present in each of the 4 isolates, cysts from only 3 of the 4 isolates took up the vital dyes. FDA consistently over-estimated cyst viability whilst PI under-estimated non-viable cysts when compared within vitroexcystation. Followingin vitroexcystation, both FDA and PI stained a proportion of unexcysted cysts indicating that FDA stained cysts which were incapable of excystation, whereas PI did not stain all cysts which were incapable of excystation. One human cyst isolate, which underwentin vitroexcystation, could not be stained with either FDA or PI. In the absence of currently more specific fluorescent indicators of viability, PI alone could be used to determine the lower limit of nonviability in positive water-related samples, where small numbers of cysts are to be expected.

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A Novel Method Combining FTIR-ATR Spectroscopy and Stable Isotopes to Investigate the Kinetics of Nitrogen Transformations in Soils

Soil Science Society of America Journal ◽

10.2136/sssaj2013.08.0358dgs ◽

2014 ◽

Vol 78 (1) ◽

pp. 54-60 ◽

Cited By ~ 10

Author(s):

Oz Kira ◽

Raphael Linker ◽

Avi Shaviv

Keyword(s):

Stable Isotopes ◽

Nitrogen Transformations ◽

Novel Method ◽

Atr Spectroscopy ◽

Kinetics Of

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Permeabilization activated reduction in fluorescence: A novel method to measure kinetics of protein interactions with intracellular structures

Cytoskeleton ◽

10.1002/cm.21314 ◽

2016 ◽

Vol 73 (6) ◽

pp. Spc1-Spc1

Author(s):

Pali P. Singh ◽

Jenci L. Hawthorne ◽

Christie A. Davis ◽

Omar A. Quintero

Keyword(s):

Protein Interactions ◽

Novel Method ◽

Kinetics Of

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Abstract W P32: CSF Volumetric Analysis Reliably Quantifies Cerebral Edema And Correlates With Clinical Deterioration In Large Hemispheric Infarcts

Stroke ◽

10.1161/str.46.suppl_1.wp32 ◽

2015 ◽

Vol 46 (suppl_1) ◽

Author(s):

Kristy Yuan ◽

Rajat Dhar ◽

Tobias Kulik ◽

Yasheng Chen ◽

Laura Heitsch ◽

...

Keyword(s):

Cerebral Edema ◽

Infarct Volume ◽

Intraclass Correlation ◽

Volumetric Analysis ◽

Midline Shift ◽

Stroke Patients ◽

Novel Method ◽

Kinetics Of ◽

Over Time

Background: Large hemispheric infarcts (LHI) may be complicated by cerebral edema. Midline shift (MLS), a standard radiographic measure, only crudely estimates extent of edema. Volumetric analysis of CSF compartments over time may provide a reliable and accurate means of quantifying severity and kinetics of edema after LHI. Methods: We retrospectively identified stroke patients with NIHSS≥8 and baseline CT within 6 hours who developed cerebral edema (without hemorrhage) on follow-up (FU) CTs. Two raters outlined the sulci and lateral ventricles ipsilateral (IL) and contralateral (CL) to the infarct on baseline and serial FU CTs (both within 48 hours and at peak edema, 2-5 days post-stroke) and quantified CSF and infarct volumes. Changes in compartment volumes from baseline to peak edema CT were correlated with MLS and edema-related neurologic worsening (need for hemicraniectomy, osmotic therapy, or decline in GCS, associated with MLS≥5mm). Results: Ten patients were analyzed (median NIHSS 14, time to early FU CT 30 hours, IQR 15-37 and to peak edema CT 75 hours, IQR 64-95). Inter-rater reliability for volume measures was excellent (intraclass correlation >0.97). CSF volume diminished by 37±20% (49 ml) from baseline to peak edema, over half occurring within 48 hours; net decline in CSF volume correlated with infarct volume (r=-0.63,p=0.05). Greatest reductions in CSF were seen in IL sulci and IL ventricles (Figure, top), but it was % reduction in CL sulci that correlated best with MLS (Fig, bottom), even adjusting for infarct volume (p=0.02). Decline in volumes of IL and CL sulci were greater in the 5 subjects with neurological worsening (89% vs. 56% and 40% vs. 3%, p<0.05), while infarct volume was not. Conclusions: CSF volumetrics is a reliable tool for quantifying cerebral edema after LHI and a novel method of studying edema kinetics. Loss of sulcal volume correlates with MLS and is more strongly associated with edema-related deterioration than infarct volume alone.

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