David Lee Nelson

Universidade Federal dos Vales do Jequitinhonha e Mucuri

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María das Graças Cardoso

Universidade Federal de Lavras

Michael M. Cox

University of Wisconsin–Madison

Wilder Douglas Santiago

Universidade Federal de Lavras

Vanúzia Rodrigues Fernandes Ferreira

Universidade Federal de Lavras

Alex Rodrigues Silva Caetano

Universidade Federal de Lavras

Rafaela Magalhães Brandão

Universidade Federal de Lavras

Luís Roberto Batista

Universidade Federal de Lavras

Sandro L. Barbosa

Universidade Federal dos Vales do Jequitinhonha e Mucuri

Vívian Machado Benassi

Universidade Federal dos Vales do Jequitinhonha e Mucuri

Richard Bispo Barbosa

Universidade Federal de Lavras

Cooperative Institutions

Universidade Federal de Lavras

188

Universidade Federal dos Vales do Jequitinhonha e Mucuri

134

Universidade Federal de Minas Gerais

113

National Research Institute of Brewing

University of Wisconsin–Madison

Universidade de São Paulo

National Institutes of Health

Baylor College of Medicine

Universidade Estadual Paulista (Unesp)

Universidade Federal de Viçosa

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Calcium fluxes in isolated acinar cells from rat parotid. Effect of adrenergic and cholinergic stimulation.

Journal of Biological Chemistry (1977)

Bonnie E. Miller David Lee Nelson

Rat parotid acinar cells dispersed by a combination of enzymatic treatments remain sensitive to adrenergic and cholinergic agonists. Previous studies have implicated Ca2+ in both adrenergic and cholinergic responses. This paper describes the effects of adrenergic and cholinergic stimulation upon 45Ca2+ fluxes in isolated parotid acinar cells. Suspensions of dispersed cells took up 45Ca2+ from the medium. The net rate of isotope influx was increased by the adrenergic agonists epinephrine, norepinephrine, isoproterenol, and phenylephrine, and by the cholinergic agonists acetylcholine and carbamylcholine. In 1 mM Ca2+, epinephrine was capable of increasing the 45Ca2+ influx in 40 min to three times that of resting cells. Isoproterenol, a beta-adrenergic agonist, was only half as effective as epinephrine in stimulating maximal calcium uptake although it was equally effective in stimulating maximal amylase release in the same cells. Experiments with the alpha-adrenergic antagonist phentolamine, the beta-adrenergic antagonist propranolol, and the cholinergic antagonist atropine confirmed that alpha- and beta-adrenergic and cholinergic stimulation each had a direct stimulatory effect on 45Ca2+ uptake. N6,O2'-Dibutyryl adenosine 3':5'-monophosphate also caused some stimulation of net calcium uptake. Direct measurement of Ca2+ efflux indicated that the increased calcium uptake in the presence of epinephrine was not the indirect result of a decrease in efflux. The rates of both basal and epinephrine-stimulated calcium uptake increased with increasing calcium concentration in the medium. Epinephrine had little effect on the rate of calcium uptake at 0.15 mM Ca2+. Although the energy poison NaCN had little effect on the basal rate of calcium uptake, the stimulable component of calcium uptake was inhibited by NaCN at all calcium concentrations tested (0.2 to 4.1 mM).

Phentolamine

Phenylephrine

Adrenergic antagonist

10.1016/s0021-9258(17)40299-7

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Citations (56)

The Cause and Cure of Infidelity: Including a Notice of the Author's Unbelief, and the Means of His Rescue

David Lee Nelson

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Composition of the essential oil from the leaves of tree domestic varieties and one wild variety of the guava plant (Psidium guajava L., Myrtaceae)

Revista Brasileira de Farmacognosia (2010)

Rafaela Karin Lima María das Graças Cardoso Milene Aparecida Andrade Evandro A. Nascimento Sérgio Antônio Lemos de Morais

The compositions of the essential oils from the leaves of three domestic varieties of the guava tree Psidium guajava L. (Paluma, Século XXI and Pedro Sato) and of one wild variety were compared. Essential oils were extracted by steam distillation, the components were identified by gas chromatography coupled to mass spectrometry GC-MS, and the apparent concentrations were determined by gas chromatography with a flame ionization detector. The results demonstrated that the three essential oils contained many common substances with a prevalence of 1,8-cineole, whereas the essential oil of the Paluma variety contained 1,8-cineole (42.68%) as the major constituent, as well as α-terpineol (38.68%). The principal components of the essential oil of the Século XXI variety were 1,8-cineole (18.83%), trans-caryophyllene (12.08%), and selin-11-en-4-αol (20.98%), while those of the Pedro Sato variety and of the wild plant were 1,8-cineole (17.68%) and (12.83%), caryophyllene oxide (9.34%) and (9.09%), and selin-11-en-4-α-ol (21.46%) and (22.19%), respectively.

Psidium

Myrtaceae

Flame ionization detector

Steam distillation

Eucalyptol

10.1590/s0102-695x2010000100009

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Citations (23)

Report of the Fifth International Workshop on Human X Chromosome Mapping 1994 (Part 1 of 4)

Cytogenetic and Genome Research (1994)

H.F. Willard F.P.M. Cremers Jean‐Louis Mandel Anthony P. Monaco David Lee Nelson

10.1159/000133870

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Citations (46)

Development and characterization of pectin films containing nanoemulsions of the essential oil from Thymus vulgaris for preserving salami

Food Chemistry (2025)

Cássia Duarte Oliveira María das Graças Cardoso Luciano de Souza Sílvia Vieira Geraldo de Sousa Cândido

Pectin

Thymus vulgaris

Characterization

10.1016/j.foodchem.2025.142786

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Citations (1)

Biochemical studies of the excitable membrane of Paramecium tetraurelia. II. Phospholipids of ciliary and other membranes

Biochimica et Biophysica Acta (BBA) - Biomembranes (1979)

Douglas Andrews David Lee Nelson

10.1016/0005-2736(79)90205-0

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Citations (52)

On the role of higher alcohols in the characterization of cachaça

Research Society and Development (2020)

Amazile Biagioni Maia Lorena Simão Marinho David Lee Nelson

There is a growing interest in chemical markers for the identification and certification of cachaça as a cane spirit produced in Brazil. It is known that the higher alcohols that are usually analyzed (propyl alcohol, Isobutyl alcohol and isoamyl alcohol) occur in all alcoholic beverages (fermented and distilled), but the relative proportions can vary markedly according to the peculiarities of the raw material and the production process. In this work, the contents of higher alcohols in 300 samples of alembic cachaça were compared, 220 from the state of Minas Gerais and 80 from other states, as well as three samples of industrial cachaça and 14 samples of whiskeys of various brands. The typical range of total higher alcohols in cachaça was 180-360 mg/100 mL ethanol. Cachaça containing higher alcohol concentrations greater than 360 mg/100 mL ethanol do not comply with Brazilian legislation. However, cachaças with higher alcohols concentrations below 180 mg/100 mL ethanol, as was found in one of the industrial cachaças, signify adulteration, for example, by mixing with fuel alcohol. The C4/C5 ratio varied less than the C3/C5 ratio, being consistently within the range of 0.20-0.50. In the whiskeys analyzed, the concentrations of higher alcohols were in the range of 160 and 270 mg/100 mL. Therefore, this parameter would not assist in differentiating between cachaça and whiskey. But the C4/C5 ratio was consistently different, being always greater than 0.50 for the whiskeys. Thus, the routine analysis of higher alcohols provides useful information both for tracking possible fraud and for assessments related to the identity or origin of cachaça.

Isoamyl alcohol

10.33448/rsd-v9i10.9135

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Citations (1)

Regulation of ciliary motility by membrane potential in Paramecium: A role for cyclic AMP

Cell Motility and the Cytoskeleton (1986)

Nancy M. Bonini Michael C. Gustin David Lee Nelson

Abstract The membrane potential of Paramecium controls the frequency and direction of the ciliary beat, thus determining the cell's swimming behavior. Stimuli that hyperpolarize the membrane potential increase the ciliary beat frequency and therefore increase forward swimming speed. We have observed that (1) drugs that elevate intracellular cyclic AMP increased swimming speed 2–3‐fold, (2) hyperpolarizing the membrane potential by manipulation of extracellular cations (e.g., K + ) induced both a transient increase in, and a higher sustained level of cyclic AMP compared to the control, and (3) the swimming speed of detergent‐permeabilized cells in MgATP was stimulated 2‐fold by the addition of cyclic AMP. Our results suggest that the membrane potential can regulate intracellular cAMP in Paramecium and that control of swimming speed by membrane potential may in part be mediated by cAMP.

10.1002/cm.970060303

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Citations (114)

Overexpression of the human NFM subunit in transgenic mice modifies the level of endogenous NFL and the phosphorylation state of NFH subunits.

The Journal of Cell Biology (1995)

Pang-Hsien Tu Gregory A. Elder Robert A. Lazzarini David Lee Nelson John Q. Trojanowski

Neurofilaments (NFs), the major intermediate filaments of central nervous system (CNS) and peripheral nervous system (PNS) neurons, are heteropolymers formed from the high (NFH), middle (NFM), and low (NFL) molecular weight NF subunits. To gain insights into how the expression of NF subunit proteins is regulated in vivo, two transgenes harboring coding sequences for human NFM (hNFM) with or without the hNFM multiphosphorylation repeat domain were introduced into mice. Expression of both hNFM constructs was driven by the hNFM promoter and resulted in increased levels of hNFM subunits concomitant with an elevation in the levels of mouse NFL (mNFL) proteins in the CNS of both lines of transgenic mice. The increased levels of mNFL appear specific to NFM because previous studies of transgenic mice overexpressing either NFL or NFH did not result in increased expression of either of the other two NF subunits. Further, levels of the most heavily phosphorylated isoforms of mouse NFH (mNFH) were reduced in the brains of these transgenic mice, and electron microscopic studies showed a higher packing density of NFs in large-diameter CNS axons of transgenic versus wild-type mice. Thus, reduced phosphorylation of the mNFH carboxy terminal domain may be a compensatory response of CNS neurons to the increase in NFs, and reduced negative charges on mNFH sidearms may allow axons to accommodate more NFs by increasing their packing density. Taken together, these studies imply that NFM may play a dominant role in the in vivo regulation of the levels of NFL protein, the stoichiometry of NF subunits, and the phosphorylation state of NFH. NFM and NFH proteins may assume similar functions in regulation of NF packing density in vivo.

Neurofilament

10.1083/jcb.129.6.1629

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Citations (88)

Biochemical studies of the excitable membrane of Paramecium tetraurelia. VII. Sterols and other neutral lipids of cells and cilia.

Journal of Lipid Research (1983)

Todd M. Hennessey David Andrews David Lee Nelson

The neutral lipid content of cells and cilia of Paramecium tetraurelia was determined as a function of growth stage and of growth medium composition. The major sterol(s) of deciliated cells and of cilia were the sterol provided in the growth medium (e.g., stigmasterol) and its 7-dehydro derivative. Body sterol esters and triglycerides accumulated during exponential cell growth and became depleted during stationary phase. Isolated cilia contained neither sterol esters nor triglycerides. The ratio of phospholipid to free sterol in cilia was constant (approximately 5:1) throughout exponential growth in axenic or bacterized medium, but the relative proportions of free sterol and 7-dehydrosterol varied with growth phase and with growth medium composition. Cholesterol did not support the growth of Paramecium, but was taken up rapidly into cells and cilia as the free sterol and its 7-dehydro derivative. The fatty acids of sterol esters and of triglycerides were similar to those of membrane phospholipids.

Stigmasterol

Growth medium

10.1016/s0022-2275(20)37962-1

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Citations (33)