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Biomedical subjects

B Gross

Publications and source records attributed to B Gross.

At least 73 records · Page 4Linked to original sources
PubMed1991

The 5'-untranslated region of p23 mRNA from the Ehrlich ascites tumor is involved in translation control of the growth related protein p23.

The growth-related protein p23 of the Ehrlich ascites tumor (EAT) is preferentially expressed in the exponentially growing tumor; its synthesis is translationally controlled. p23 mRNA is efficiently translated in the wheat germ cell-free lysate. In contrast, p23 mRNA present in poly(A)+RNA isolated from EAT is not translated in cell-free systems of EAT and reticulocytes. Moreover, translation of a p23 transcript is inhibited in the presence of total poly(A)+RNA. This inhibition is abolished by the removal of the 5'-UTR of the p23 transcript. Solution hybridization/RNase protection experiments point to the presence of a nucleotide sequence complementary to the 5'-UTR of p23 mRNA which might be involved in p23 mRNA inhibition.

Animals↗
PubMed1991

Comparison of two cytochromes P-450 from Candida maltosa: primary structures, substrate specificities and effects of their expression in Saccharomyces cerevisiae on the proliferation of the endoplasmic reticulum.

cDNAs were cloned, sequenced and expressed which encode two different cytochrome P-450 forms of the alkane-assimilating yeast Candida maltosa, designated as P-450Cm1 and P-450Cm2. The amino acid sequences deduced were about 55% identical. Expression in Saccharomyces cerevisiae resulted in the formation of intact microsomal P-450 systems catalyzing the hydroxylation of n-hexadecane and lauric acid with significantly different substrate preferences. A massive proliferation of the endoplasmic reticulum was observed in the S. cerevisiae cells which produced P-450. Depending on the P-450 form expressed, distinctly organized stacks of paired membranes appeared and occupied considerable areas of the cytoplasm. As shown by immunoelectron microscopy for P-450Cm1, the protein expressed was highly concentrated within these newly formed membrane structures.

Amino Acid Sequence↗
PubMed1990

Progesterone receptor stimulates transcription of mouse mammary tumour virus in a cell-free system.

In higher eukaryotes, steroid receptors are general modulators of gene activity which bind to DNA hormone response elements (HREs) in the vicinity of regulated promoters. Analysis of mutant and chimaeric receptor proteins in gene transfer experiments has identified the domains responsible for hormone binding, interaction with the HREs and transactivation, but the transactivating function of hormone receptors has proved difficult to reproduce in cell-free assays. Here we describe a crude in vitro system in which transcription from the mouse mammary tumour virus (MMTV) promoter is increased up to 10-fold by native progesterone receptor from rabbit uterus. The stimulatory effect must depend on receptor binding to the MMTV-HRE as it is abolished by deletion or mutation of the HRE and by HRE-oligonucleotide competition. The nuclear factor-I binding site immediately downstream of the HRE, however, does not appear to be essential to progesterone receptor-mediated in vitro stimulation of MMTV transcription. The transactivation activity of the progesterone receptor depends on binding of a functional ligand and so this assay should be useful for dissection of the mechanism of transcription activation by steroid hormones.

Animals↗
PubMed1989

Modification of the Na-dependent action potential in myelinated fibers of rat sciatic nerve exposed to phorbol ester.

Exposure of rat sciatic nerve to the active phorbol 1,2-beta-myristate-13-acetate (b-PMA), but not to the active analogue 4-alpha-phorbol-12,13-didecanoate (a-PDD), is followed by a decrease of the compound action potential amplitude, rate of rise, and conduction velocity, and an increase of the threshold, and of the duration of the refractory period. The effect is concentration-dependent, the Kd being 250 nM. The attenuated Na-dependent action potential is tetrodotoxin (TTX)-sensitive, but after exposure to b-PMA the sensitivity to TTX is decreased from Kd = 45 nM to 400 nM. Action potential depression is larger when Ca is replaced by Mg (but not by Ba), or when Na is replaced by Li. The replacement of K by Cs, or exposure to potassium channel blockers such as 4-aminopyridine (4AP) and tetra-ethyl ammonium (TEA) has no effect. The results indicate that in the myelinated axons of rat sciatic nerve, exposure to b-PMA induces modification of Na channels.

Action Potentials↗
PubMed1989

Molecular cloning and characterization of the primary structure of the alkane hydroxylating cytochrome P-450 from the yeast Candida maltosa.

A cDNA library was established starting from poly(A) RNA of n-alkane-grown Candida maltosa cells and cDNA clones were isolated containing the entire coding sequence for the alkane hydroxylating cytochrome P-450. The deduced protein consists of 521 amino acids, contains two putative transmembrane segments in the N-terminal region and has a characteristic heme-binding sequence in the C-terminal part. Sequence alignments with members of 11 reported cytochrome P-450 families revealed a strong homology to an alkane-inducible cytochrome P-450 from Candida tropicalis.

Amino Acid Sequence↗
PubMed1989

Molecular cloning, sequencing and expression in Escherichia coli of the 25-kDa growth-related protein of Ehrlich ascites tumor and its homology to mammalian stress proteins.

The growth-related 25-kDa protein (p25) of Ehrlich ascites tumor (EAT) has been characterized by molecular cloning and sequencing of cDNA clones detected by hybridization with oligonucleotide probes synthesized according to the amino acid sequence of a tryptic peptide of p25. Detection of p25 mRNA in EAT of the exponential growth phase and of the stationary phase using cDNA-derived RNA probes demonstrated that the abundance of p25 mRNA is also growth-related. High-level expression of p25 in Escherichia coli has been established by oligonucleotide-directed mutagenesis of cDNA and insertion of the mutated cDNA into a T7-promoter expression vector. Recombinant p25 from the expressed cDNA sequence has been shown to comigrate with EAT p25 in electrophoresis and to react with antibodies against the EAT p25. On the amino acid level, p25 shows about 80% sequence homology to the human stress protein hsp27. Furthermore, p25 has similar isoforms of phosphorylation as demonstrated for small mammalian stress proteins from rat and human. From the results obtained, it is concluded that p25 is a mammalian stress protein, the abundance of which is related to growth characteristics of the Ehrlich ascites tumor.

Amino Acid Sequence↗
PubMed1989

Interleaved 31P NMR with transcutaneous nerve stimulation (TNS): a method of monitoring compliance-independent skeletal muscle metabolic response to exercise.

31P NMR spectroscopy was used to monitor the metabolic response of the tibialis anterior muscle group to transcutaneous nerve stimulation of the peroneal nerve at a rate of 4 Hz for 5 min in human volunteers (n = 8). It is demonstrated that this technique can be used as a method of investigating effort-free and compensation-independent skeletal muscle exercise.

Adult↗
PubMed1989

Comparative antimicrobial activity of the new macrolides against Borrelia burgdorferi.

The in vitro and in vivo activity of the new macrolides azithromycin, clarithromycin and roxythromycin was compared with that of erythromycin against Borrelia burgdorferi. In in vitro tests using ten clinical isolates all macrolides were highly active against Borrelia burgdorferi (MIC90 0.015-0.06 micrograms/ml). Azithromycin was more potent than the other macrolides in experimental animal infection, eradicating the organism in all animals tested at a dosage of 8 mg/kg.

4-Quinolones↗
PubMed1989

Incidence, mortality, and case-fatality rate of stroke in northern Israel.

We studied the incidence and mortality of stroke in northern Israel to determine possible reasons for the differences previously found in mortality from this condition between the sex and ethnic groups in Israel as a whole. We identified 1,149 cases of stroke during 1984. While the age-standardized incidence was higher in men, the case-fatality rate was twice as high in women. After controlling for ethnic origin, we found that incidence was higher only in men of Western origin, while the female rates were higher in women of Asian and North African extraction. The case-fatality rate was substantially higher in women in all ethnic groups. These differences, especially in relation to the case-fatality rate, have important implications for health services in relation to both possible preventive action and to management of the acute disease phase.

Age Factors↗
PubMed1989

Inhibition of expression of SV40 virus large T-antigen by antisense oligodeoxyribonucleotides.

Expression of large T-antigen in COS cells can be inhibited by treatment of cell monolayers with oligodeoxyribonucleotides complementary to large T mRNA, which were covalently linked to poly-L-lysine. Strongest inhibition was observed with conjugates of oligodeoxynucleotides that hybridize to the sequence immediately 3' to the cap structure of the mRNA. Treatment of SV40 virus-infected CV-1 cells with the same conjugates reduces the virus-induced large T-antigen expression by more than 80%.

Animals↗
PubMed1989

The growth-related protein P23 of the Ehrlich ascites tumor: translational control, cloning and primary structure.

p23 is a protein of Ehrlich ascites tumor cells, preferentially synthesized in the exponentially growing tumor. In vitro, serum and actinomycin D rapidly induce p23 synthesis. Using transcription inhibitors and a wheat germ cell-free translation system, evidence is provided that the synthesis of p23 is under translational control. Actinomycin D even results in superinduction of p23. Polymerase chain reaction, cloning and sequencing of p23 cDNA suggest p23 to be identical with a 21 kDa protein of mouse erythroleukemia cells, the synthesis of which was shown to be controlled also at the translational level (Chitpatima, S. T., Makrides, S., Bandyopadhyay, R., and Brawerman, G. (1988) Nucleic Acids Res. 16, 2350).

Amino Acid Sequence↗
PubMed1988

Differential gene activation by glucocorticoids and progestins through the hormone regulatory element of mouse mammary tumor virus.

The hormone regulatory element (HRE) of mouse mammary tumor virus can mediate activation of an adjacent promoter by glucocorticoids and progestins. A detailed comparison of the DNA binding of receptors for both hormones using DNAase I footprinting and methylation protection detects clear differences in their interactions with the HRE region between positions -130 and -100. Binding studies and gene transfer experiments with a variety of mutants covering the entire HRE demonstrate differences in the relevance of the individual sequence motifs for induction by each hormone. The influence of changes in the angular orientation of receptor binding sites is also different for glucocorticoid and progesterone induction. In transfection experiments with mutated HREs, we find a functional cooperation between the receptor binding sites that does not correlate with variations in the in vitro affinity of the receptors for the corresponding DNA fragment.

Animals↗
PubMed1987

Studies on interaction of 5 S RNA with ribosomal proteins.

Proteins of the large ribosomal subunit of rat liver (TP 60) were immobilized by diffusion transfer onto nitrocellulose after two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Incubation of the TP 60 blots with 32P-labeled 5 S RNA under defined ionic conditions (300 mM KCl, 20 mM MgCl2) resulted in specific binding to a limited set of ribosomal proteins consisting of proteins L3, L4, L6, L13/15 and--to a lesser extent--L7 and L19. Under identical conditions, blots with proteins of the small ribosomal subunit (TP 40) did not bind 5 S RNA.

Carrier Proteins↗