Phosphorus and proton magnetic resonance spectroscopic studies on the relationship between transparency and glucose metabolism in the rabbit lens

Williams, Wanda F.; Austin, Cary D.; Farnsworth, Patricia N.; Groth-Vasselli, Barbara; Willis, James; Schleich, Thomas

doi:10.1016/0014-4835(88)90027-9

Cited by 14 publications

(5 citation statements)

References 21 publications

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“…Furthermore, since nonexponential relaxation behavior was not observed, the influence of cross-relaxation as a contributing relaxation mechanism appears to be insignificant. In addition, the increase in 7, values with B0 field for PME and GPC and the field-independent ATP 7, values (Williams et al, 1988) are consistent with fast exchange (on the Tx time scale) between mobile and more slowly tumbling metabolites. The fast-exchange assumption was also employed by Moonen et al (1986) in the analysis of kidney phosphorus metabolite 7, relaxation data.…”

Section: Discussionsupporting

confidence: 60%

“…Phosphorus metabolites bound to solidlike protein domains would be NMR "invisible" in spectra obtained by use of the usual high-resolution NMR instrumentation and spectral acquisition conditions. For example, in liver ATP has been reported not to be 100% observable by 3IP NMR (Murphy et al, 1988) whereas ADP is usually NMR "invisible" in many tissues (lies et al, 1985) including lens under many conditions (Greiner et al, 1981(Greiner et al, , 1982Willis & Schleich, 1986;Williams et al, 1988). Line width calculations for a phosphomonoester assuming intramolecular and intermolecular DD and CSA relaxation mechanism contributions indicate that a t0 value of l µ$ would result in a line width of ca.…”

Section: Discussionmentioning

confidence: 99%

“…An understanding of the glycolytic pathway regulatory process requires, in part, knowledge of the availability, utilization, and generation of phosphorus metabolites in lenticular metbolic processes (Farnsworth et al, 1989). Standard biochemical assays (Harding & Crabbe, 1984;Cheng & Chylack, 1985) and noninvasive 31P nuclear magnetic resonance (NMR)1 spectroscopic techniques (Greiner et al, 1981(Greiner et al, , 1982(Greiner et al, , 1985; Willis & Schleich, 1986; Williams et al, 1988) have been employed to assess the identity and concentration of lens phosphorus metabolites. These studies indicate that there is a metabolic million; ,, longitudinal (spin-lattice) relaxation time; T2, transverse relaxation time; NOE, nuclear Overhauser enhancement; rf, radiofrequency; HSVD, Hankel singular value decomposition; PME, phosphomonoester; P[, inorganic phosphate; PCr, phosphocreatine; GPC, L-aglycerophosphocholine; NTP, nucleotide triphosphate; NDP, nucleotide diphosphate; ATP, adenosine triphosphate; ADP, adenosine diphosphate; DN, dinucleotide; UDPG, uridinediphosphoglucose; G-3-P, L-a-glycerol phosphate; 2,3-BPG, 2,3-bisphosphoglycerate; BSA, bovine serum albumin.…”

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confidence: 99%

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Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates

Gh¹,

Schleich²,

Cf³

et al. 1990

Biochemistry

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The rotational diffusion behavior of phosphorus metabolites present in calf lens cortical and nuclear homogenates was investigated by the NMR technique of 31P off-resonance rotating frame spin-lattice relaxation as a means of assessing the occurrence and extent of phosphorus metabolite-lens protein interactions. 31P NMR spectra of calf lens homogenates were obtained at 10 and 18 degrees C (below and above the cold cataract phase transition temperature, respectively) at 7.05 T. Effective rotational correlation times (tau 0,eff) for the major phosphorus metabolites present in cortical and nuclear bovine calf lens homogenates were derived from nonlinear least-squares analysis of R vs omega e (spectral intensity ratio vs precessional frequency about the effective field) data with the assumption of isotropic reorientational motion. Intramolecular dipole-dipole (1H-31P, 31P-31P), chemical shift anisotropy (CSA), and solvent (water) translational intermolecular dipole-dipole (1H-31P) relaxation contributions were assumed in the analyses. In those cases where the limiting value of the spectral intensity ratio failed to reach unity at large offset frequency, a modified formalism incorporating chemical exchange mediated saturation transfer between two sites was used. Values of tau 0,eff for phosphorus metabolites present in the cortex varied from a low of ca. 2 ns [L-alpha-glycero-phosphocholine (GPC)] to a high of 12 ns (alpha-ATP) at 10 degrees C, whereas at 18 degrees C the range was from ca. 1 to 9 ns. For the nucleus the tau 0,eff values ranged from ca. 3 ns (GPC) to 41 ns (Pi) at 10 degrees C; at 18 degrees C the corresponding values ranged from 4 to 39 ns. For PME (phosphomonoester; in lens the predominant metabolite is L-alpha-glycerol phosphate) at 18 degrees C evidence was obtained for binding and subsequent exchange with solid like protein domains. The diversity in tau 0,eff values for lenticular phosphorus metabolites is suggestive of differential binding to more slowly tumbling macromolecular species, most likely lens crystallin proteins. Corresponding measurement of tau 0,eff values for the mobile protein fraction present in calf lens cortical and nuclear homogenates at 10 and 18 degrees C, by 13C off-resonance rotating frame spin-lattice relaxation, provided average macromolecular correlation times that were assumed to represent the bound metabolite state. A fast-exchange model (on the T1 time scale), between free and bound forms, was employed in the analysis of the metabolite R vs omega e curves to yield the

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Section: Discussionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates

Gh¹,

Schleich²,

Cf³

et al. 1990

Biochemistry

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“…In mature lens fiber cells, ATP, GSH, myo-inositol, NADPH, and polyols are needed to preserve protein solubility and SRO and to protect against light scattering and opacity. Several publications summarize the importance of lens metabolism to the maintenance of protein solubility, stability, structure, symmetric microcirculation, and resist oxidative and osmotic stress (87,93,(249)(250)(251)(252)(253)(254)(255)(256)(257).…”

Section: Metabolic Adaption and Lens Transparencymentioning

confidence: 99%

Insights into the biochemical and biophysical mechanisms mediating the longevity of the transparent optics of the eye lens

Quinlan

Clark

2022

Journal of Biological Chemistry

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“…These observations negate the hypothesis proposed by Greiner et al [1985] that depressed ATP levels result in a cascading sequence of events which include the alteration of meta bolic rates, intracellular water structure changes, edema, alterations in cell ultra structure and, ultimately, opacification. Our work [Williams et al, 1988;Groth-Vasselli et al, 1988] demonstrates that ultrastruc tural changes and cataract formation need not to be accompanied by alterations in organophosphate content, and that HMPS ac tivity is a sensitive marker of prior and/or current lenticular stress. We propose as a working hypothesis that alterations in HMPS activity ultimately reflect, at the macromolecular level, a change in organization which is responsible for opacification.…”

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confidence: 99%

Studies on the Molecular Organization of the Lens

Farnsworth

Schleich²,

Groth-Vasselli³

et al. 1988

Ophthalmic Res

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Based on recent findings from our laboratories, we propose the working hypothesis that the macromolecular organization of the outer cortex is dependent upon a functional link which occurs between actin, γ-crystallin and metabolism. This hypothesis is rooted in the following observations: (1) actin polymerization is energy-dependent; (2) exogenously added γ-crystallin modifies the rate, extent and pattern of actin polymerization in vitro; (3) the metabolite L-α-glycerol phosphate appears to bind to γ-crystallin, and (4) glycolytic enzymes occur in an organized array on actin filaments.

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Phosphorus and proton magnetic resonance spectroscopic studies on the relationship between transparency and glucose metabolism in the rabbit lens

Cited by 14 publications

References 21 publications

Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates

Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates

Insights into the biochemical and biophysical mechanisms mediating the longevity of the transparent optics of the eye lens

Studies on the Molecular Organization of the Lens

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