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1.
Milk fat globule size is determined by the size of its precursors—intracellular lipid droplets—and is tightly associated with its composition. We examined the relationship between phospholipid composition of mammary epithelial cells and the size of both intracellular and secreted milk fat globules. Primary culture of mammary epithelial cells was cultured in medium without free fatty acids (control) or with 0.1 mM free capric, palmitic or oleic acid for 24 h. The amount and composition of the cellular lipids and the size of the lipid droplets were determined in the cells and medium. Mitochondrial quantity and expression levels of genes associated with mitochondrial biogenesis and polar lipid composition were determined. Cells cultured with oleic and palmitic acids contained similar quantities of triglycerides, 3.1- and 3.8-fold higher than in controls, respectively (P < 0.0001). When cultured with oleic acid, 22% of the cells contained large lipid droplets (>3 μm) and phosphatidylethanolamine concentration was higher by 23 and 63% compared with that in the control and palmitic acid treatments, respectively (P < 0.0001). In the presence of palmitic acid, only 4% of the cells contained large lipid droplets and the membrane phosphatidylcholine concentration was 22% and 16% higher than that in the control and oleic acid treatments, respectively (P < 0.0001). In the oleic acid treatment, approximately 40% of the lipid droplets were larger than 5 μm whereas in that of the palmitic acid treatment, only 16% of the droplets were in this size range. Triglyceride secretion in the oleic acid treatment was 2- and 12-fold higher compared with that in the palmitic acid and control treatments, respectively. Results imply that membrane composition of bovine mammary epithelial cells plays a role in controlling intracellular and secreted lipid droplets size, and that this process is not associated with cellular triglyceride content. 相似文献
2.
External ATP enhanced stomatal opening of Commelina communis L. differently from EDTA. ATP was more effective in opening stomata than EDTA, when both were applied in amounts yielding equivalent free Ca2+ concentration. The stimulation by ATP depended upon its de-phosphorylation and was not due to the P1 released. Hence an energetical contribution of external ATP appears possible. Increase in CO2 concentration increased the stimulation of stomatal opening by ATP and diminished the internal ATP level, ATP/(ADP+AMP) ratio and respiration rate. 相似文献
3.
Alexander E. Gad Carmi Lubitz-Omero Nurit Rosenberg Arie Altman 《Plant cell reports》1988,7(5):341-343
Negatively charged large unilamellar vesicles (LUV) were incubated with tobacco (Nicotiana tabacum var. xanthi) cell suspensions and with the cell-free medium of the cell suspensions. The extent of cell-LUV interaction was determined by the leakage of the LUV contents. Cells enhanced the leakage of LUV contents and this effect increased with cell age. Addition of polylysine to the reaction mixture increased even further the leakage of the LUV contents. The cell-free medium of the cell suspension also affected the integrity of the LUV. Cell-free medium, by itself, promoted leakage of LUV contents and caused a reduction in the leakage exerted by polylysine. Centrifugation (8000g) of the cell-free medium decreased its effect, heat treatment (122°C) did not alter its effect and sonication enhanced it. The effects of the cell-free medium are attributed to the presence of cell wall debris of disintegrated cells. 相似文献
4.
Nurit Eyal Nurit Firon Sylvia Wilder Edwin H. Kolodny Mia Horowitz 《Human genetics》1991,87(3):328-332
Summary Single-stranded cDNA was prepared from RNA obtained from a patient with type 1 Gaucher disease. The cDNA was amplified in vitro and analyzed by sequencing. Three base-pair changes were identified which included a G to C transversion at nucleotide 3119 of the active gene (Asp140His), an A to C transversion at nucleotide 3170 (Lys157Gln) and a G to A change at nucleotide 5309 (Glu326Lys). To study the mode of inheritance of the three different base-pair changes, genomic DNA was prepared from blood or skin fibroblasts of several family members. Genomic glucocerebrosidase DNA sequences were amplified and subjected to hybridization with allele-specific oligonucleotides (ASOs). The hybridization profiles demonstrated that two of the basepair changes originated from the mother and were transmitted to her two affected sons and to a grandchild, while the third base-pair change, originating from the father, was transmitted to his two affected sons, a carrier daughter and a second grandchild. Tests of other patients with Gaucher disease failed to disclose the presence of the three base-changes. This is a unique family with three base-pair changes tightly linked to Gaucher disease. 相似文献
5.
The tiny seeds of parasitic weeds of the genusOrobanche can be identified by using RAPD markers. A simple procedure for DNA extraction from single seeds, 10 μg each, followed by
RAPD-PCR and using specific DNA markers, leads to species identification. Seeds of five different species could be identified
using this method. 相似文献
6.
Vered Yesodi Shamay Izhar David Gidoni Yona Tabib Nurit Firon 《Molecular genetics and genomics : MGG》1995,248(5):540-546
In petunia, a mitochondrial (mt) locus,S-Pcf, has been found to be strongly associated with cytoplasmic male sterility (CMS). TheS-Pcf locus consists of three open reading frames (ORF) that are co-transcribed. The first ORF,Pcf, contains parts of theatp9 andcoxII genes and an unidentified reading frame,urf-s. The second and third ORFs contain NADH dehydrogenase subunit 3 (nad3) and ribosomal protein S12 (rps12) sequences, respectively. Thenad3 andrps12 sequences included in theS-Pcf locus are identical to the corresponding sequences on the mt genome of fertile petunia. In both CMS and fertile petunia, only a single copy ofnad3 andrps12 has been detected on the physical map of the main mt genome. The origin of theurf-s sequence and the molecular events leading to the formation of the chimericS-Pcf locus are not known. This paper presents evidence indicating that two different mt sequences, related tourf-s and found in fertile petunia lines (orf-h and Rf-1), might have been involved in the molecular evolution of theS-Pcf locus. Southern analysis of mtDNA derived from both fertile and sterile petunia plants suggests that one of theseurf-s related sequences (showing 100% homology tourf-s and termedorf-h) is located on a sublimon. An additional, low-homologyurf-s related sequence (Rf-1) is shown to be located on the main mt genome 5′ to thenad3 gene. It is, thus, suggested that the sequence of events leading to the generation of theS-Pcf locus might have involved introduction of theorf-h sequence, via homologous recombination, into the main mt genome 5′ tonad3 at the region where the Rf-1 sequence is located. 相似文献
7.
Vered Yesodi Shamay Izhar David Gidoni Yona Tabib Nurit Firon 《Molecular & general genetics : MGG》1995,248(5):540-546
In petunia, a mitochondrial (mt) locus,S-Pcf, has been found to be strongly associated with cytoplasmic male sterility (CMS). TheS-Pcf locus consists of three open reading frames (ORF) that are co-transcribed. The first ORF,Pcf, contains parts of theatp9 andcoxII genes and an unidentified reading frame,urf-s. The second and third ORFs contain NADH dehydrogenase subunit 3 (nad3) and ribosomal protein S12 (rps12) sequences, respectively. Thenad3 andrps12 sequences included in theS-Pcf locus are identical to the corresponding sequences on the mt genome of fertile petunia. In both CMS and fertile petunia,
only a single copy ofnad3 andrps12 has been detected on the physical map of the main mt genome. The origin of theurf-s sequence and the molecular events leading to the formation of the chimericS-Pcf locus are not known. This paper presents evidence indicating that two different mt sequences, related tourf-s and found in fertile petunia lines (orf-h and Rf-1), might have been involved in the molecular evolution of theS-Pcf locus. Southern analysis of mtDNA derived from both fertile and sterile petunia plants suggests that one of theseurf-s related sequences (showing 100% homology tourf-s and termedorf-h) is located on a sublimon. An additional, low-homologyurf-s related sequence (Rf-1) is shown to be located on the main mt genome 5′ to thenad3 gene. It is, thus, suggested that the sequence of events leading to the generation of theS-Pcf locus might have involved introduction of theorf-h sequence, via homologous recombination, into the main mt genome 5′ tonad3 at the region where the Rf-1 sequence is located.
Contribution [No. 1581-E (1995 series)] from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
50 250 相似文献
8.
Nurit Nardi Galya Avidan Dvorah Daily Rina Zilkha-Falb Ari Barzilai 《Journal of neurochemistry》1997,68(2):750-759
Abstract: We analyzed biochemically and temporally the molecular events that occur in the programmed cell death of mouse cerebellar granule neurons deprived of high potassium levels. An hour after switching the neurons to a low extracellular K+ concentration ([K+]o), a significant part of the genomic DNA was already cleaved to high-molecular-weight fragments. This phenomenon was intensified with the progression of the death process. Addition of cycloheximide to the neurons 4 h after high [K+]o deprivation resulted in no cell loss and complete recovery of the damaged DNA. DNA margination and nuclear fragmentation as assessed by 4,6-diaminodiphenyl-2-phenylindole staining were observable in a few cells beginning ~4 h after the removal of high [K+]o and developed to nuclear condensation 4 h later. Six hours after high [K+]o deprivation, the DNA was fragmented into oligonucleosome-sized fragments. Within 6 h after removal of the extracellular K+, 50% of the neurons were committed to die and lost their ability to be rescued by readministration of 25 mM [K+]o. Similar to high [K+]o deprivation, inhibition of RNA or protein synthesis failed to halt neuronal degeneration of a similar percentage of cells 6 h after the onset of the death process. Mitochondrial function steadily decreased after [K+]o removal. An ~40% decrease in RNA and protein synthesis was detected by 6 h of [K+]o removal during the period of cell death commitment; rates continued to decline gradually thereafter. The temporal characteristics of the DNA damage and recovery, DNA cleavage to oligonucleosome-sized fragments, and the reduction in mitochondrial activity—events that occurred within the critical time—may indicate that these processes have an important part in the mechanism that committed the neurons to die. 相似文献
9.
Marlene Belfort Nava Kass Ariella Oppenheim Nurit Katzir Amos B. Oppenheim 《Molecular & general genetics : MGG》1977,155(3):347-349
Summary Analysis of phage infection of the host mutant ER437 by SDS polyacrylamide gel electrophoresis and autoradiography has revealed altered expression of repressor and integration function (Int). We show that in this host Int as well as repressor synthesis is not dependent upon the cIII gene product in the usual manner, nor is their synthesis turned off in the normal way. 相似文献
10.
Inhibition of pancreatic lipase by mixed micelles of diethyl p-nitrophenyl phosphate and bile salts 总被引:1,自引:0,他引:1
M Rouard H Sari S Nurit B Entressangles P Desnuelle 《Biochimica et biophysica acta》1978,530(2):227-235
Solubility and Sephadex filtration assays have shown that dissolved diethyl p-nitrophenyl phosphate can be included into bile salt micelles with a partition coefficient of 32 : 1. This inclusion is probably a prerequisite for the organophosphate to inhibit lipase. The essential role played by colipase confirms that the primary step in the inhibition is an interaction of lipase with bile salt containing micelles. Therefore, it appears that the requirements of lipase towards specific substrates and inhibitors are very similar. The inhibition rate strongly depends on the total bile salt concentration and on the micellar concentration of the organophosphate. This effect may be explained, at least qualitatively, by a competition between simple and mixed micelles for the binding of colipase and lipase. 相似文献