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E Fodor

Publications and source records attributed to E Fodor.

At least 55 records · Page 3Linked to original sources
PubMed1993

Photochemical cross-linking of influenza A polymerase to its virion RNA promoter defines a polymerase binding site at residues 9 to 12 of the promoter.

A previous study of the 12 nucleotide-long influenza A virion RNA promoter has shown that three nucleotides, residues 9 to 11, were crucial for transcription in vitro, although other nucleotides play a significant but less important role. A model for polymerase-promoter recognition was proposed, according to which there were two sites: a binding site at residues 9 to 11 and a regulatory site at or near the site of initiation at residue 1. By studying the effect of point mutations in the promoter on the binding efficiency of the polymerase using a photochemical cross-linking assay, we now show that residues 9 to 12 are crucial for binding. In addition residues 4 to 8, though not as important, are involved in binding, possibly by stabilizing the polymerase-promoter complex. Both PB1 and PB2 apparently play an important role during virion RNA promoter recognition and binding.

Animals↗
PubMed1993

Effect of nutrients on plasma corticosteroid concentration in cold-stressed rats.

Little is known about the mechanisms as to how nutrients affect plasma corticosteroids in cold-stressed and starved animals. Therefore, cold-stressed rats (maintained at 7 degrees C) were fasted (control) or fed a balanced diet (casein 20 wt%, fat 5 wt%, starch 70 wt% and vitamin-mineral premix 5 wt%) or the following dietary nutrients for 72 h: casein, lard, starch, glycerol, stearic acid, leucine or glutamic acid. The animals were then killed and plasma corticosteroid concentrations (PCC) were determined. PCC were significantly reduced (p < 0.05) in cold-stressed animals fed a balanced diet (16.95 micrograms/100 ml plasma) compared to the fasted cold-stressed controls (FCSC) (24.16 micrograms/100 ml plasma). Additionally, corticosteroid concentrations (micrograms/100 ml plasma) of animals fed the following specific nutrients were also significantly lower than the FCSC values: starch (15.53), lard (12.01), stearic acid (12.74), glycerol (13.32) and leucine (16.03). Casein and glutamic acid did not significantly alter plasma corticosteroid levels relative to the FCSC concentration. It is concluded that certain specific building blocks of nutrient classes, i.e. stearic acid or glycerol, can alter PCC to the same extent as the parent compound (lard), however the individual components of casein, a complex nutrient, i.e. leucine, a ketogenic amino acid, versus glutamic acid, a glycogenic amino acid, may elicit a different PCC effect.

Adrenal Cortex Hormones↗
PubMed1991

A pancreatic exocrine cell factor and AP4 bind overlapping sites in the amylase 2A enhancer.

A factor found in pancreatic exocrine cell lines and pancreatic nuclei binds selectively to the alpha-amylase 2A transcriptional enhancer. Pancreatic exocrine cell extracts protect asymmetrically an unusually large, 35 base pair region from DNase I digestion in vitro, suggesting the involvement of a multimeric DNA binding complex. We show that this region of the enhancer contains a major affinity recognition sequence for the HeLa transcription factor AP4. A 4 base pair mutation in the enhancer sequence shown previously to abolish activity in vivo [Boulet, A. M., Erwin, C. R., & Rutter, W. J. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 3599-3603] abolishes AP4 binding in vitro and weakens but does not eliminate the binding of adjacent enhancer factors. Further, sequences similar to the AP4 binding site are found within a consensus sequence of most pancreatic exocrine genes (Boulet et al., 1986). We have identified three AP4 binding sites in the pancreatic elastase gene: one occurs in the consensus sequence of the enhancer. Thus, protein(s) with the binding selectivity of AP4 may play a role in the expression of the pancreatic exocrine gene family.

Amylases↗
PubMed1991

Investigation of Shiga-like toxin binding to chemically synthesized oligosaccharide sequences.

Shiga-like toxin (SLT)-I and SLT-II/IIc bound to Synsorbs containing synthetic alpha Gal(1-4)beta Gal (P1 disaccharide), alpha Gal(1-4)beta GlcNAc (P1 trisaccharide), or alpha Gal(1-4)beta Gal(1-4)beta Glc (Pk trisaccharide) sequences but not to Synsorbs containing alpha Gal(1-3)beta Gal, alpha Gal(1-3)beta Gal(1-4)beta GlcNAc, or the hydrophobic oligosaccharide linkage arm. SLT-I had a preference for Synsorbs containing trisaccharides, whereas SLT-II/IIc binding was less selective. 125I-labeled SLT-I remained bound to Pk trisaccharide Synsorb in the presence of lactose, galactose, or EDTA but was partially released by acetic acid, guanidine HCl, or a 10% solution of SDS. Vero cells coincubated with Pk trisaccharide Synsorb and SLT I extract were protected from this toxin, whereas Pk trisaccharide Synsorb was much less efficient at neutralizing SLT-II/IIc activity in Vero cell coincubation experiments. The SLT-IIc component was not responsible for the inefficient neutralization. Results suggest that synthetic oligosaccharide sequences related to the P blood group antigens coupled to inert matrices could be useful for rapid diagnosis or possibly therapeutic intervention in enterohemorrhagic Escherichia coli infections.

Animals↗
PubMed1990

[Preventive value of vitamin D in various doses based on a prospective study of healthy infants].

Authors have kept under review two groups of healthy full-term infants born from undisturbed pregnancy, who lived in good social conditions from birth to one year of age. One of the groups was given 500IU/die and the other 1200 IU/die vitamin D. Authors evaluated the effect of the different doses of vitamin D on the prophylaxis of the rickets. 100 infants were reviewed in both groups. The clinical, laboratory and radiological examination revealed symptoms referring to rickets at the half of infants in both groups as early as 3 month of age. In the group of infants having been given low prophylactic dose of vitamin D there was significantly larger number of patients showing clinical evidence for rickets in both ages. Also significant differences were found at the age of one year in the size of the anterior fontanelles and the head circumferences, the developing of dentition and walk and the disturbed rank of eruption of teeth.

Age Determination by Skeleton↗
PubMed1990

Pan: a transcriptional regulator that binds chymotrypsin, insulin, and AP-4 enhancer motifs.

Two cDNAs were cloned that encode proteins (Pan-1 and Pan-2, with predicted molecular masses of 67.4 and 67.7 kD, respectively) that bind to a conserved transcriptional regulatory element present in pancreatic exocrine genes. The cDNAs are virtually identical in the region that encodes the amino-terminal 525 amino acids; they differ only by a 3-nucleotide insertion that results in the addition of a single amino acid. The cDNAs, however, code for related, but divergent, carboxy-terminal regions. Expression of the cloned cDNAs in HeLa cells activates expression of a cotransfected chimeric gene containing multimers of the pancreatic conserved element linked to a minimal promoter. Pan-1 and Pan-2 bind to the consensus sequence CAC/GCTGT/C, the CACCTGTC motif, which is present in transcriptional control elements of several genes. Both Pan-1 and Pan-2 bind to related motifs present in the rat insulin enhancer as well as a DNA segment containing the SV40 AP-4 element. The Pan-1 and Pan-2 cDNAs display extensive sequence identity with partial cDNA clones encoding E12 and E47, which bind to the immunoglobulin kappa E2 cis-active element, and may be derived from the same gene. These factors belong to a set of genetically distinct molecules, including AP-4 and MLTF, that bind to the CACCTGTC motif or related sequences. The Pan/E12,E47 proteins also show structural similarity with the Drosophila daughterless protein, MyoD, Myogenin, and Myf-5.

Amino Acid Sequence↗
PubMed1988

Capturing nuclear sequence-specific DNA-binding proteins by using simian virus 40-derived minichromosomes.

We have used recombinant simian virus 40 (SV40) minichromosomes to retrieve sequence-specific DNA-binding proteins derived from the cell nucleus of COS-7 cells. We showed that the transcription factors AP-1 and Sp1 are stably bound to the SV40 DNA late in viral infection. Under similar conditions, minichromosomes carrying the rat insulin (rINS1) enhancer, which is under negative regulation in COS-7 cells, bound two proteins which mapped to distinct regions of the rINS1 enhancer. The SV40 P element competed for one of these proteins which bound to the region from -198 to -230. This factor may be related to AP-1. The other factor selectively bound a regulatory element in the region from -92 to -124 of the insulin enhancer. These proteins may play a role in regulating the rINS1 enhancer function.

Animals↗
PubMed1984

Cell-specific expression of heat shock proteins in chicken reticulocytes and lymphocytes.

We have found that chicken reticulocytes respond to elevated temperatures by the induction of only one heat shock protein, HSP70, whereas lymphocytes induce the synthesis of all four heat shock proteins (89,000 mol wt, HSP89; 70,000 mol wt, HSP70; 23,000 mol wt, HSP23; and 22,000 mol wt, HSP22). The synthesis of HSP70 in lymphocytes was rapidly induced by small increases in temperature (2 degrees-3 degrees C) and blocked by preincubation with actinomycin D. Proteins normally translated at control temperatures in reticulocytes or lymphocytes were not efficiently translated after incubation at elevated temperatures. The preferential translation of mRNAs that encode the heat shock proteins paralleled a block in the translation of other cellular proteins. This effect was most prominently observed in reticulocytes where heat shock almost completely repressed alpha- and beta-globin synthesis. HSP70 is one of the major nonglobin proteins in chicken reticulocytes, present in the non-heat-shocked cell at approximately 3 X 10(6) molecules per cell. We compared HSP70 from normal and heat-shocked reticulocytes by two-dimensional gel electrophoresis and by digestion with Staphylococcus aureus V8 protease and found no detectable differences to suggest that the P70 in the normal cell is different from the heat shock-induced protein, HSP70. P70 separated by isoelectric focusing gel electrophoresis into two major protein spots, an acidic P70A (apparent pl = 5.95) and a basic P70B (apparent pl = 6.2). We observed a tissue-specific expression of P70A and P70B in lymphocytes and reticulocytes. In lymphocytes, P70A is the major 70,000-mol-wt protein synthesized at normal temperatures whereas only P70B is synthesized at normal temperatures in reticulocytes. Following incubation at elevated temperatures, the synthesis of both HSP70A and HSP70B was rapidly induced in lymphocytes, but synthesis of only HSP70B was induced in reticulocytes.

Anemia↗
PubMed1982

The effect of pure Fusarium toxins (T-2, F-2, DAS) on the microflora of the gut and on plasma glucocorticoid levels in rat and swine.

The gut microflora and adrenal cortex hormone levels were monitored in HUNGAHYB piglets of 10-12 kg and in Wistar rats of 100-150 g body weight fed with different pure Fusarium toxins. The feeding of either T-2, T-2 + F-2 and DAS toxins at the 5 microgram/g feed level for one week resulted in the substantial increase of aerobic bacteria count of the intestine. Increase of the DAS dose to a twofold level failed to elicit dose-response and no further increases in bacterial counts were observed. Following the uptake of toxin containing feed, the plasma cortisol and corticosterone levels showed a 2-3 fold rise. Intramuscular administration of toxin T-2 also increased the activity of the adrenal cortex and gut microflora counts also increased. It is suggested that the observed changes in the gut microflora may contribute to the appearance of clinical symptoms developing after feeding of toxins as well as to the triggering and maintaining of the stress.

17-Hydroxycorticosteroids↗