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Biomedical subjects

N Gardner

Publications and source records attributed to N Gardner.

At least 19 recordsLinked to original sources
PubMed2005

Production of Propionibacterium shermanii biomass and vitamin B12 on spent media.

AIMS: The propionibacteria are commercially important due to their use in the cheese industry, and there is a growing interest for their probiotic effects. Stimulatory effects of lactic acid bacteria (LAB) on propionic acid bacteria have been observed. This study was designed to examine the possibility of using spent media previously used to grow LAB for the production of biomass and metabolites of Propionibacterium freudenreichii subsp. shermanii. METHODS AND RESULTS: Seventeen MRS and vegetable juice media were prefermented by various LAB and evaluated for their ability to subsequently support the growth of Propionibacterium, using automated spectrophotometry (AS). Growth of Propionibacterium in spent media was strongly affected by the LAB strain used to produce the spent medium. The native MRS medium (not prefermented) yielded the highest optical density values followed by prefermented media by Lactobacillus acidophilus, Bifidobacterium longum and Lactococcus lactis. Prefermented cabbage juice enabled good growth of Propionibacterium. For the production of organic acids and vitamin B12, cells of Propionibacterium were concentrated and immobilized in alginate beads in the aim of accelerating the bioconversions. More propionic acid was obtained in spent media than in native MRS. The concentration of vitamin B12 was higher in media fermented with free cells than those with immobilized cultures; with the free cells, its concentration varied from 900 to 1800 ng ml(-1) of media. CONCLUSIONS: It was demonstrated that spent media could be recycled for the production of Propionibacterium and metabolites, depending on the LAB strain that was previously grown. Media remediation is needed to improve the production of vitamin B12, especially with immobilized cells. SIGNIFICANCE AND IMPACT OF THE STUDY: This study presents an option for recycling of spent media generated by producers of LAB or producers of fermented vegetables. The propionic fermentation may result in three commercial products: biomass, vitamin B12 or organic acids, which may be used as starters, supplements or food preservatives. It is an attractive process from economical and environmental standpoints.

Alginates↗
PubMed2002

Driving safety in Parkinson's disease.

In this study, 39 patients with PD and 25 control subjects without neurologic disease completed testing in a driving simulator. PD patients had more total collisions on the driving simulator than control subjects (t = -3.7, p < 0.01). In PD patients, collisions were associated with Hoehn and Yahr stage (chi(2) = 12.4, p = 0.006) and correlated with Unified Parkinson's Disease Rating Scale score (r = 0.5, p < 0.01).

Accidents, Traffic↗
PubMed2001

Family ties.

Explore the source record for details and available documents.

Arkansas↗
PubMed2001

My mama told me.

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Evidence-Based Medicine↗
PubMed2000

NADH dehydrogenase in Neurospora crassa contains myristic acid covalently linked to the ND5 subunit peptide.

The mitochondrial, proton-pumping NADH:ubiquinone oxidoreductase consists of at least 35 subunits whose synthesis is divided between the cytosol and mitochondria; this complex I catalyzes the first steps of mitochondrial electron transfer and proton translocation. Radiolabel from [(3)H]myristic acid was incorporated by Neurospora crassa into the mitochondrial-encoded, approximately 70 kDa ND5 subunit of NADH dehydrogenase, as shown by immunoprecipitation. This myristate apparently was linked to the peptide through an amide linkage at an invariant lysine residue (Lys546), based upon analyses of proteolysis products. The myristoylated lysine residue occurs in the predicted transmembrane helix 17 (residues 539-563) of ND5. A consensus amino acid sequence around this conserved residue exists in homologous subunits of NADH dehydrogenase. Cytochrome c oxidase subunit 1, in all prokaryotes and eukaryotes, contains this same consensus sequence surrounding the lysine which is myristoylated in N. crassa.

Consensus Sequence↗
PubMed2000

Doctors' complaints help forge insurance regulation. Payment due.

Arkansas doctors are banning to help draft a regulation that would require health maintenance organizations and insurance carriers to process health care claims within 45 calendar days after receipt of a claim. The proposed regulation would be administered by the Arkansas Department of Insurance. If additional information from a claimant is needed to process a claim, a carrier must notify a provider within 10 days of receipt of the claim. Once that information is received by the carrier, it has an additional 45 days to pay.

Arkansas↗
PubMed1999

Regulation of human D1 dopamine receptor function and gene expression in SK-N-MC neuroblastoma cells.

SK-N-MC human neuroblastoma cells express functional D1, but not D5, dopaminergic receptors. Stimulating cells with dopamine or the D1-selective agonist, SKF R-38393, rapidly (t(1/2) = 1 h) resulted in > 95% attenuation of dopamine-mediated accumulation of cyclic AMP, without any change in D1 dopamine receptor levels. Prolonged (> 4 h) exposure of cells to dopamine attenuated D1 receptor levels to 45-50% of control (t(1/2) = 8 h) and was accompanied by a loss of high-affinity binding sites. At the molecular level, the expression of D1 receptor messenger RNA was bimodal: an initial increase (by approximately 60%) of receptor messenger RNA within 2 h of treatment of cells with dopamine was followed by a decline to 50% below control messenger RNA levels. Low concentrations (1-10 nM) of dopamine also potentiated D1 messenger RNA levels (up to 48%), resulting in a twofold increase in receptor levels. Transfection studies with the cloned human D1 promoter construct, pGL-D1P, indicated that the up-regulation of D1 messenger RNA was due to activation of promoter by dopamine. The dopamine-mediated up-regulation of both D1 receptor messenger RNA and promoter was prevented by the D1-selective antagonist, SCH 23390. The results suggest that dopamine regulates D1 receptor gene and protein expression in a bimodal manner, partly through activation of the receptor promoter. Moreover, the effects of dopamine are independent of the second messenger, cyclic AMP.

1-Methyl-3-isobutylxanthine↗
PubMed1999

Disruption of the gene for Hsp30, an alpha-crystallin-related heat shock protein of Neurospora crassa, causes defects in import of proteins into mitochondria.

The gene for Hsp30, the only known alpha-crystallin-related heat shock protein of Neurospora crassa, was disrupted by repeat-induced point mutagenesis, leading to loss of cell survival at high temperature. Hsp30, which is not synthesized at 30 degrees C, associates reversibly with the mitochondria at high temperature (45 degrees C). In this study, we found that import of selected proteins into internal compartments of mitochondria, following their synthesis in the cytosol, was severely impaired at high temperature in a strain mutant in Hsp30. After 70 min of cell incubation at 45 degrees C, most matrix, inner membrane, and intermembrane-space proteins tested were reduced in import by about 50-70% in the mutant, as compared to wild-type cells. In contrast, assembly of selected proteins into the outer mitochondrial membrane was not reduced, except for one component of the preprotein translocase complex of the mitochondrial outer membrane. Three proteins of this complex co-immunoprecipitated with Hsp30 of wild-type cells incubated at 45 degrees C. We propose that Hsp30 interacts with the preprotein translocase of the mitochondrial outer membrane and that it chaperones the activity of one or more components of this translocase complex at high temperature.

Adenosine Triphosphatases↗