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1.
McNulty IB 《Plant physiology》1985,78(1):100-103
The objective of this research was to measure the short term osmotic adjustment of Salicornia europaea L. ssp. rubra (A. Nels) Breitung when suddenly exposed to 100 millimolar NaCl. Plants were grown hydroponically, shocked with 100 millimolar NaCl added to the culture solution, and stem tips analyzed for free inorganic ions and small organic molecules at intervals up to 72 hours. In the first 2 hours, the calculated leaf osmoticum showed a net increase of 158.8 millimolar most of which was free Mg2+ (+135.3 millimolar). Total sugars increased almost 5-fold by the 6th hour, enough to provide sufficient osmoticum for the cytoplasm if only partially confined there. By 24 hours, all measured osmotica had decreased except Na+, Mg2+, Cl−, and proline, with the net increase being 208 millimolar. By 72 hours, there was a net gain of 356 millimolar in osmotica of the stem tips, due to Na+ (+233.3 millimolar), Cl− (+306.7 millimolar), and a small increase in sugar and proline (+3.5 millimolar), with all other osmotica decreasing in concentration. Compatible osmotica did not change sufficiently to account for osmotic balance between vacuole and cytoplasm; consequently, there must have been a reapportionment of osmotica within the cell in the short time duration of this experiment. 相似文献
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In man folates are catabolized and excreted as inactive cleaved degradation products, a mixture of pteridines and p-aminobenzoylglutamate (pABGlu) or its acetamido derivative (apABGlu). The daily rate of excretion represents the inescapable use of the vitamin in metabolic activity and thus has implications for determining the recommended dietary allowance for the vitamin. Furthermore, the rate of catabolism has been suggested to rise during pregnancy and in certain disease states. A method is described for the quantitative extraction and assay of the folate catabolites pABGlu and apABGlu in human urine. Aliquots of 24-h urine collections are acidified and applied to columns of Dowex 50W cation-exchange resin. The catabolites are selectively batch-eluted with increasing concentrations of HCl. The fraction containing pABGlu is diazotized and then applied to a C18 Sep Pak column for further purification and concentration. The fraction containing apABGlu was deacetylated and reapplied to the Dowex column and then treated identically to the pABGlu fraction. The methanolic concentrates of both extracts were evaporated to dryness and reconstituted with water and pABGlu was regenerated by reductive cleavage of the diazotized material with Zn/HCl. The extracts of the two catabolites were separated by reverse-phase HPLC using a Radial Pak C18 column. Recovery of isolated material was monitored by the addition of high specific activity tritiated labels of both compounds added as internal standards to all urine aliquots prior to purification and analysis. 相似文献
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Dr. J. A. McNulty 《Cell and tissue research》1978,195(3):535-545
Summary The pineal organ of the blind, cave-dwelling fish, Typhlichthyes subterraneous, was examined with both light and electron microscopes. Like the eyes, the pineal in this troglobytic species was found to be regressed. Two cell types, photoreceptor and supportive cells, were described in the pineal epithelium. Although ganglion cells were not identified, small, unmyelinated nerve fibers were present. The photoreceptor cells had degenerated outer segments. Accordingly, it was suggested that the pineal in this species is not likely to function in photoreception. However, the presence of well developed Golgi bodies, clear and dense-cored vesicles, variable amounts of rough endoplasmic reticulum and glycogen particles indicated that both cell types are metabolically active and may play a role in secretion. 相似文献
6.
Dr. John A. McNulty 《Cell and tissue research》1980,210(2):249-256
Summary Synaptic ribbons in the pineal organ of the goldfish were examined electron microscopically with particular attention to their topography. These structures were formed of parallel membranes, which were poorly preserved with OsO4 fixation and could be extracted from thin sections with pronase indicating their proteinaceous nature. Synaptic ribbons were closely apposed to the plasma membrane bordering dendrites of ganglion cells, but were also related to processes of both photoreceptor and supportive cells. Their close proximity to invaginations of the plasma membrane and portions of the endoplasmic reticulum suggest that they are involved in the turnover of cytoplasmic membranes. Tubular and spherical organelles of unknown function are also described. 相似文献
7.
Standard DNA-RNA hybridization studies, using nucleic acids isolated from mammalian tissues, are frequently hindered by relatively low levels of radioactivity in pulse-labeled RNA and in an inability to reliably estimate the amount of DNA present in the hybrid. In the method described here nuclear RNA is labeled in vitro with 125I to 400 000- 800 000 cpm/mug and DNA is obtained from a rat glial tumor line grown in culture and labeled to specific activities of 42 000-79 000 cpm/mug. DNA-RNA hybridization is conducted in an all solution system at RNA:DNA ratios of 3.5:1 to 18:1. Assay background is controlled by pretreatment of the hybrid and free RNA at the conclusion of the annealing study with RNase, then isolation of the hybrid together with a small fraction of free RNA oligonucleotides on hydroxyapatite. The partially purified hybrids are then trapped on Millipore filters. Assay background id 0.004% of total counts present in the annealing reaction. Comparison of the annealing reactions of pulse-labeled liver nuclear RNA and in vitro 125I-labeled nuclear RNA in saturation, kinetic, and competitive hybridization studies shows them to be essentially the same. Nuclear RNA labeled by either tritium or iodine shows a 10-20-fold greater concentration of the annealing sequences over that found in the microsomal RNA. Minor differences are noted between the nuclear RNAs in the initial rates of reaction and in the magnitude of the decrease in percent hybridization at low levels of unlabeled competitor RNA. This may be due to preferential labeling in pulse-labeled RNA of molecules which are present in lower concentrations or are transcribed from more frequently repeated DNA sequences than the average population of annealing RNA molecules. The technique has application in systems where the amount of tissue for RNA extraction is small or where the system does not permit the obtaining of pulse-labeled RNA, as in experimental rodent skin carcinogenesis or in dealing with RNA from the tissues of large mammals or humans. 相似文献
8.
Shannon McNulty Mike Flint Stuart T. Nichol Christina F. Spiropoulou 《Journal of virology》2013,87(2):912-922
Hantavirus pulmonary syndrome (HPS) is a severe respiratory disease characterized by pulmonary edema, with fatality rates of 35 to 45%. Disease occurs following infection with pathogenic New World hantaviruses, such as Andes virus (ANDV), which targets lung microvascular endothelial cells. During replication, the virus scavenges 5′-m7G caps from cellular mRNA to ensure efficient translation of viral proteins by the host cell cap-dependent translation machinery. In cells, the mammalian target of rapamycin (mTOR) regulates the activity of host cap-dependent translation by integrating amino acid, energy, and oxygen availability signals. Since there is no approved pharmacological treatment for HPS, we investigated whether inhibitors of the mTOR pathway could reduce hantavirus infection. Here, we demonstrate that treatment with the FDA-approved rapamycin analogue temsirolimus (CCI-779) blocks ANDV protein expression and virion release but not entry into primary human microvascular endothelial cells. This effect was specific to viral proteins, as temsirolimus treatment did not block host protein synthesis. We confirmed that temsirolimus targeted host mTOR complex 1 (mTORC1) and not a viral protein, as knockdown of mTORC1 and mTORC1 activators but not mTOR complex 2 components reduced ANDV replication. Additionally, primary fibroblasts from a patient with tuberous sclerosis exhibited increased mTORC1 activity and increased ANDV protein expression, which were blocked following temsirolimus treatment. Finally, we show that ANDV glycoprotein Gn colocalized with mTOR and lysosomes in infected cells. Together, these data demonstrate that mTORC1 signaling regulates ANDV replication and suggest that the hantavirus Gn protein may modulate mTOR and lysosomal signaling during infection, thus bypassing the cellular regulation of translation. 相似文献
9.
Siddique A. Abbasi Ravi V. Shah Steven E. McNulty Adrian F. Hernandez Marc J. Semigran Gregory D. Lewis Michael Jerosch-Herold Raymond J. Kim Margaret M. Redfield Raymond Y. Kwong 《PloS one》2016,11(11)
Given the emerging recognition of left atrial structure and function as an important marker of disease in heart failure with preserved ejection fraction (HF-pEF), we investigated the association between left atrial volume and function with markers of disease severity and cardiac structure in HF-pEF. We studied 100 patients enrolled in the PhosphdiesteRasE-5 Inhibition to Improve CLinical Status and EXercise Capacity in Diastolic Heart Failure (RELAX) trial who underwent cardiac magnetic resonance (CMR), cardiopulmonary exercise testing, and blood collection before randomization. Maximal left atrial volume index (LAVi; N = 100), left atrial emptying fraction (LAEF; N = 99; including passive and active components (LAEFP, LAEFA; N = 80, 79, respectively) were quantified by CMR. After adjustment for multiple testing, maximal LAVi was only associated with age (ρ = 0.39), transmitral filling patterns (medial E/e’ ρ = 0.43), and N-terminal pro-BNP (NT-proBNP; ρ = 0.65; all p<0.05). Lower LAEF was associated with older age, higher transmitral E/A ratio and higher NT-proBNP. Peak VO2 and VE/VCO2 slope were not associated with left atrial structure or function. After adjustment for age, sex, transmitral E/A ratio, CMR LV mass, LV ejection fraction, and creatinine clearance, NT-proBNP remained associated with maximal LAVi (β = 0.028, p = 0.0007) and total LAEF (β = -0.033, p = 0.001). Passive and active LAEF were most strongly associated with age and NT-proBNP, but not gas exchange or other markers of ventricular structure or filling properties. Left atrial volume and emptying function are associated most strongly with NT-proBNP and diastolic filling properties, but not significantly with gas exchange, in HFpEF. Further research to explore the relevance of left atrial structure and function in HF-pEF is warranted. 相似文献
10.
Goda N Ryan HE Khadivi B McNulty W Rickert RC Johnson RS 《Molecular and cellular biology》2003,23(1):359-369