scholarly journals Blockade of dorsolateral pontine 5HT1A receptors destabilizes the respiratory rhythm in C57BL6/J wild-type mice

2016 ◽  
Vol 226 ◽  
pp. 110-114 ◽  
Author(s):  
R.R. Dhingra ◽  
M. Dutschmann ◽  
T.E. Dick
Keyword(s):  
Respiratory Rhythm ◽  
Wild Type ◽  
5Ht1a Receptors

Altered responses of MeCP2-deficient mouse brain stem to severe hypoxia

2011 ◽  
Vol 105 (6) ◽  
pp. 3067-3079 ◽  
Author(s):  
Miriam Kron ◽  
Jasper L. Zimmermann ◽  
Mathias Dutschmann ◽  
Frank Funke ◽  
Michael Müller
Keyword(s):  
Brain Stem ◽  
Respiratory Rhythm ◽  
Respiratory Arrest ◽  
Wild Type ◽  
Cardiorespiratory Control ◽  
Breathing Disorders ◽  
Life Threatening ◽  
Deficient Mice

Rett syndrome (RTT) patients suffer from respiratory arrhythmias with frequent apneas causing intermittent hypoxia. In a RTT mouse model (methyl-CpG-binding protein 2-deficient mice; Mecp2−/ y) we recently discovered an enhanced hippocampal susceptibility to hypoxia and hypoxia-induced spreading depression (HSD). In the present study we investigated whether this also applies to infant Mecp2−/ y brain stem, which could become life-threatening due to failure of cardiorespiratory control. HSD most reliably occurred in the nucleus of the solitary tract (NTS) and the spinal trigeminal nucleus (Sp5). HSD susceptibility of the Mecp2−/ y NTS and Sp5 was increased on 8 mM K+-mediated conditioning. 5-HT1A receptor stimulation with 8-hydroxy-2-(di-propylamino)tetralin (8-OH-DPAT) postponed HSD by up to 40%, mediating genotype-independent protection. The deleterious impact of HSD on in vitro respiration became obvious in rhythmically active slices, where HSD propagation into the pre-Bötzinger complex (pre-BötC) immediately arrested the respiratory rhythm. Compared with wild-type, the Mecp2−/ y pre-BötC was invaded less frequently by HSD, but if so, HSD occurred earlier. On reoxygenation, in vitro rhythms reappeared with increased frequency, which was less pronounced in Mecp2−/ y slices. 8-OH-DPAT increased respiratory frequency but failed to postpone HSD in the pre-BötC. Repetitive hypoxia facilitated posthypoxic recovery only if HSD occurred. In 57% of Mecp2−/ y slices, however, HSD spared the pre-BötC. Although this occasionally promoted residual hypoxic respiratory activity (“gasping”), it also prolonged the posthypoxic recovery, and thus the absence of central inspiratory drive, which in vivo would lengthen respiratory arrest. In view of the breathing disorders in RTTs, the increased hypoxia susceptibility of MeCP2-deficient brain stem potentially contributes to life-threatening disturbances of cardiorespiratory control.

Ultrastructure of Melanin Formation in Curvularia sp., Alternaria sp., and Drechslera Sorokiniana

1977 ◽  
Vol 35 ◽  
pp. 398-399
Author(s):  
M. H. Wheeler ◽  
W. J. Tolmsoff ◽  
A. A. Bell
Keyword(s):  
Potassium Phosphate ◽  
Thielaviopsis Basicola ◽  
Wild Type ◽  
Potassium Phosphate Buffer ◽  
Transmission Microscopy ◽  
Electron Transmission ◽  
Melanin Formation ◽  
Before And After ◽  
Alternaria Sp ◽  
Electron Transmission Microscopy

(+)-Scytalone [3,4-dihydro-3,6,8-trihydroxy-l-(2Hj-naphthalenone] and 1,8-di- hydroxynaphthalene (DHN) have been proposed as intermediates of melanin synthesis in the fungi Verticillium dahliae (1, 2, 3, 4) and Thielaviopsis basicola (4, 5). Scytalone is enzymatically dehydrated by V. dahliae to 1,3,8-trihydroxynaphthalene which is then reduced to (-)-vermelone [(-)-3,4- dihydro-3,8-dihydroxy-1(2H)-naphthalenone]. Vermelone is subsequently dehydrated to DHN which is enzymatically polymerized to melanin.Melanin formation in Curvularia sp., Alternaria sp., and Drechslera soro- kiniana was examined by light and electron-transmission microscopy. Wild-type isolates of each fungus were compared with albino mutants before and after treatment with 1 mM scytalone or 0.1 mM DHN in 50 mM potassium phosphate buffer, pH 7.0. Both chemicals were converted to dark pigments in the walls of hyphae and conidia of the albino mutants. The darkened cells were similar in appearance to corresponding cells of the wild types under the light microscope.

Ultrastructure and Morphology of the Neurospora Crassa Cell Wall Mutants, Slime And Slime X, Using Tem and Sem

1976 ◽  
Vol 34 ◽  
pp. 54-55
Author(s):  
Karen S. Howard ◽  
H. D. Braymer ◽  
M. D. Socolofsky ◽  
S. A. Milligan
Keyword(s):  
Cell Wall ◽  
Neurospora Crassa ◽  
Wild Type ◽  
Morphological Comparison ◽  
Small Areas ◽  
Solid Media ◽  
Thin Sectioning ◽  
X Cells ◽  
Mutant Cells ◽  
Isolated Cell

The recently isolated cell wall mutant slime X of Neurospora crassa was prepared for ultrastructural and morphological comparison with the cell wall mutant slime. The purpose of this article is to discuss the methods of preparation for TEM and SEM observations, as well as to make a preliminary comparison of the two mutants.TEM: Cells of the slime mutant were prepared for thin sectioning by the method of Bigger, et al. Slime X cells were prepared in the same manner with the following two exceptions: the cells were embedded in 3% agar prior to fixation and the buffered solutions contained 5% sucrose throughout the procedure.SEM: Two methods were used to prepare mutant and wild type Neurospora for the SEM. First, single colonies of mutant cells and small areas of wild type hyphae were cut from solid media and fixed with OSO4 vapors similar to the procedure used by Harris, et al. with one alteration. The cell-containing agar blocks were dehydrated by immersion in 2,2-dimethoxypropane (DMP).

Freeze-substituted fungal cells of Nectria haematococca: A comparison of the macroconidial walls of the adhesion-competent wild type with an adhesion-reduced mutant

1990 ◽  
Vol 48 (3) ◽  
pp. 688-689
Author(s):  
Thecan Caesar-Ton That ◽  
Lynn Epstein
Keyword(s):  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Wild Type ◽  
Nectria Haematococca ◽  
Fruit Extract ◽  
Dialysis Tubing ◽  
Tube Emergence ◽  
Contrast Microscopy ◽  
In The Wild ◽  
Freeze Damage

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.

Identification of a baculovirus polyhedron formation mutant with a novel phenotype

1996 ◽  
Vol 54 ◽  
pp. 796-797
Author(s):  
James M. Slavicek ◽  
Melissa J. Mercer ◽  
Mary Ellen Kelly
Keyword(s):  
Viral Gene ◽  
Gene Products ◽  
Type Number ◽  
Infection Cycle ◽  
Wild Type ◽  
Protein Matrix ◽  
Insect Midgut ◽  
Viral Particles ◽  
Budded Virus ◽  
Viral Form

Nucleopolyhedroviruses (NPV, family Baculoviridae) produce two morphological forms, a budded virus form and a viral form that is occluded into a paracrystalline protein matrix. This structure is termed a polyhedron and is composed primarily of the protein polyhedrin. Insects are infected by NPVs after ingestion of the polyhedron and release of the occluded virions through dissolution of the polyhedron in the alkaline environment of the insect midgut. Early after infection the budded virus form is produced. It buds through the plasma membrane and then infects other cells. Later in the infection cycle the occluded form of the virus is generated (reviewed by Blissard and Rohrmann, 1990).The processes of polyhedron formation and virion occlusion are likely to involve a number of viral gene products. However, only two genes, the polyhedrin gene and 25K FP gene, have been identified to date that are necessary for the wild type number of polyhedra to be formed and viral particles occluded.

Arabidopsis 4-COUMAROYL-COA LIGASE 8 contributes to the biosynthesis of the benzenoid ring of coenzyme Q in peroxisomes

2019 ◽  
Vol 476 (22) ◽  
pp. 3521-3532
Author(s):  
Eric Soubeyrand ◽  
Megan Kelly ◽  
Shea A. Keene ◽  
Ann C. Bernert ◽  
Scott Latimer ◽  
...  
Keyword(s):  
Oxidative Metabolism ◽  
Time Course ◽  
Reverse Genetics ◽  
De Novo ◽  
Coenzyme Q ◽  
Control Level ◽  
Wild Type ◽  
Fluorescent Reporters ◽  
Coa Ligase ◽  
Peroxisomal Targeting

Plants have evolved the ability to derive the benzenoid moiety of the respiratory cofactor and antioxidant, ubiquinone (coenzyme Q), either from the β-oxidative metabolism of p-coumarate or from the peroxidative cleavage of kaempferol. Here, isotopic feeding assays, gene co-expression analysis and reverse genetics identified Arabidopsis 4-COUMARATE-COA LIGASE 8 (4-CL8; At5g38120) as a contributor to the β-oxidation of p-coumarate for ubiquinone biosynthesis. The enzyme is part of the same clade (V) of acyl-activating enzymes than At4g19010, a p-coumarate CoA ligase known to play a central role in the conversion of p-coumarate into 4-hydroxybenzoate. A 4-cl8 T-DNA knockout displayed a 20% decrease in ubiquinone content compared with wild-type plants, while 4-CL8 overexpression boosted ubiquinone content up to 150% of the control level. Similarly, the isotopic enrichment of ubiquinone's ring was decreased by 28% in the 4-cl8 knockout as compared with wild-type controls when Phe-[Ring-13C6] was fed to the plants. This metabolic blockage could be bypassed via the exogenous supply of 4-hydroxybenzoate, the product of p-coumarate β-oxidation. Arabidopsis 4-CL8 displays a canonical peroxisomal targeting sequence type 1, and confocal microscopy experiments using fused fluorescent reporters demonstrated that this enzyme is imported into peroxisomes. Time course feeding assays using Phe-[Ring-13C6] in a series of Arabidopsis single and double knockouts blocked in the β-oxidative metabolism of p-coumarate (4-cl8; at4g19010; at4g19010 × 4-cl8), flavonol biosynthesis (flavanone-3-hydroxylase), or both (at4g19010 × flavanone-3-hydroxylase) indicated that continuous high light treatments (500 µE m−2 s−1; 24 h) markedly stimulated the de novo biosynthesis of ubiquinone independently of kaempferol catabolism.

Transferrin-induced endocytosis in stably transfected HeLa cells expressing wild-type and C282Y-mutant HFE measured by patch-clamp capacitance techniques

2001 ◽  
Vol 120 (5) ◽  
pp. A564-A565
Author(s):  
L SCHWAKE ◽  
A HENKEL ◽  
H RIEDEL ◽  
B HADASCHIK ◽  
T SCHLENKER ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Hela Cells ◽  
Wild Type

Different effects of chronic helicobactor pylori infection on parietal and ECL cells between wild type and gastrin-deficient mice

2001 ◽  
Vol 120 (5) ◽  
pp. A728-A728
Author(s):  
D CHEN ◽  
L FRIISHANSEN ◽  
X WANG ◽  
C ZHAO ◽  
H WALDUM ◽  
...  
Keyword(s):  
Wild Type ◽  
Ecl Cells ◽  
Helicobactor Pylori ◽  
Deficient Mice

267: Effects of Steroidal and Non-Steroidal Antiandrogens on Wild-Type and Mutant Androgen Receptors

2007 ◽  
Vol 177 (4S) ◽  
pp. 89-90
Author(s):  
Masayasu Urushibara ◽  
Yukio Kageyama ◽  
Junichiro Ishioka ◽  
Yotsuo Higashi ◽  
Shuntaro Hara ◽  
...  
Keyword(s):  
Androgen Receptors ◽  
Wild Type
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