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F Esch

Publications and source records attributed to F Esch.

At least 37 records · Page 2Linked to original sources
PubMed1990

Isolation of a phospholipase-A2-like protein from human fetal intestine. Lysis of erythroid cells from bovine liver by this protein and porcine phospholipase A2.

Extracts of human fetal intestine contain factors that can stimulate or inhibit thymidine incorporation into fetal bovine erythroid cells. An inhibitory factor was purified to homogeneity by gel-permeation and reversed-phase high performance liquid chromatography. The inhibitory action was due to cell lysis. The first 25 amino acids of the N-terminal segment were identical to the human lung and pancreatic phospholipase A2. The isolated protein released arachidonic acid from 2-arachidonyl phosphatidylcholine. Porcine phospholipase A2 had the same effects as the intestinal protein, including its tissue-specific lysis of fetal bovine liver erythroid cells. No decrease of thymidine incorporation was seen in fetal bovine intestinal cells, 3T3 cells, or K562 cells incubated with the porcine enzyme. No release of hemoglobin or cell lysis was observed with human erythrocytes or fetal bovine erythrocytes. Porcine and bee phospholipases, which have low sequence homology, are nearly equipotent in inhibiting thymidine incorporation, whereas melittin and beta-bungarotoxin were less active than the pancreatic enzyme. These results support the tissue-specific effects observed with other phospholipases A2. The high sensitivity of liver erythroid cells towards some phospholipases A2 suggest that these enzymes may be involved in the elimination of hepatic erythroid cells at the end of gestation.

Amino Acid Sequence↗
PubMed1989

Stage dependent expression of inhibin alpha and beta-B subunits during the cycle of the rat seminiferous epithelium.

In order to elucidate the putative role of inhibin in regulation of spermatogenesis, expression of inhibin subunits was examined at defined stages of the cycle of the rat seminiferous epithelium. Twenty 2-mm segments of seminiferous tubules at stages XIII-I, II-VI, VII-VIII, and IX-XII were dissected using the transillumination technique and subunit specific messenger RNAs (mRNAs) were quantitated by filter hybridization. The alpha and beta-B subunit mRNAs varied significantly in different stages, the highest levels of both alpha and beta-B subunit expression were seen in stages XIII-I and the lowest in stages VII-VIII. The hybridization signals obtained with beta-actin probe were not significantly different between different stages indicating that the differences in the quantities of subunit mRNAs in different stages were not due to different amounts of RNA blotted. beta-A subunit mRNA levels were below the detection limit of the filter hybridization method. These data demonstrate that expression of inhibin alpha and beta-B subunits in the rat testis is stage dependent and suggest a paracrine role for inhibin-related peptides in regulation of spermatogenesis.

Animals↗
PubMed1989

Regulation of testicular inhibin subunit messenger ribonucleic acid levels in vivo: effects of hypophysectomy and selective follicle-stimulating hormone replacement.

To examine the pretranslational regulation of inhibin subunits in the rat testis by FSH, we studied the effects of hypophysectomy with or without selective FSH replacement on testicular inhibin subunit mRNA levels in immature and adult animals. In the first experiment (Exp I), sexually immature (20-23 days old) intact and hypophysectomized male rats were killed 1, 3, and 7 days after surgery, and the testicular content of inhibin subunit mRNAs was determined by filter hybridization. A second group of immature, intact, or hypophysectomized rats was treated with saline or FSH for 7 days as follows: I) intact, saline; II) hypophysectomized, saline; III) hypophysectomized, FSH [0.05 microgram/100 g BW, sc, twice daily (BID)]; IV) hypophysectomized, FSH (0.50 microgram/100 g BW, sc, BID); V) hypophysectomized, FSH (5.0 micrograms/100 g BW, sc, BID); and VI) hypophysectomized, FSH (50.0 micrograms/100 g BW, sc, BID). In the second experiment (Exp II), adult (60 days old) intact or hypophysectomized animals were treated with saline, FSH, and/or testosterone for 7 days as follows: I) intact, saline; II) hypophysectomized; saline; III) hypophysectomized, 22-mm testosterone implant; IV) hypophysectomized, FSH (50.0 micrograms/100 g BW, sc, BID; and V) hypophysectomized, 22-mm testosterone implant plus FSH (50.0 micrograms/100 g BW, sc, BID. The effects of FSH and testosterone on testicular inhibin subunit mRNA levels were measured by filter hybridization. In Exp I, the level of inhibin alpha-subunit mRNA per testis was significantly lower in hypophysectomized rats than in intact controls at all time points after surgery. Replacement of FSH to hypophysectomized immature rats led to a dose-dependent increase in alpha-subunit mRNA per testis. However, hypophysectomy and FSH replacement had no significant effect on beta-B-subunit mRNA. In adult rats (Exp II), hypophysectomy significantly lowered and FSH replacement increased testicular inhibin alpha-subunit mRNA levels. Replacement of testosterone to adult animals, either alone or in combination with FSH, had no effect on expression of inhibin alpha-subunit mRNA. beta-B mRNA levels in adult testis were not significantly altered by any of the treatments. beta-A-Subunit mRNA levels were below the detection threshold of filter hybridization in both Exp I and II. Collectively, these data demonstrate that FSH regulates alpha- but not beta-B-subunit mRNA in the testis of both immature and adult rats in vivo. Differential regulation of inhibin subunits may provide a mechanism for creation and regulation of functional diversity of inhibin-related peptides in the testis.

Animals↗
PubMed1988

Structure of a novel human granulocyte peptide with anti-ACTH activity.

We report the purification, structure and biological properties of a peptide of novel sequence from human granulocytes that inhibits ACTH stimulated synthesis of corticosterone in rat adrenal cell suspensions. The peptide HP-4 is homologous to a previously described human granulocyte peptide HP-1 that has no anti-ACTH activity.

Adrenal Glands↗
PubMed1988

Coding of two sphingolipid activator proteins (SAP-1 and SAP-2) by same genetic locus.

Several complementary DNAs (cDNAs) coding for sphingolipid activator protein-2 (SAP-2) were isolated from a lambda gt-11 human hepatoma library by means of polyclonal antibodies. The nucleotide sequence of the largest cDNA was colinear with the derived amino acid sequence of SAP-2 and with the nucleotide sequence of the cDNA coding for the 70-kilodalton precursor of SAP-1 (SAP precursor cDNA). The coding sequence for mature SAP-2 was located 3' to that coding for SAP-1 in the SAP precursor cDNA. Both SAP-1 and SAP-2 appeared to be derived by proteolytic processing from a common precursor that is coded by a genetic locus on human chromosome 10. Two other domains similar to SAP-1 and SAP-2 were also identified in SAP precursor protein. Each of the four domains was approximately 80 amino acid residues long, had nearly identical placement of cysteine residues, potential glycosylation sites, and proline residues. Each domain also contained internal amino acid sequences capable of forming amphipathic helices separated by helix breakers to give a cylindrical hydrophobic domain that is probably stabilized by disulfide bridges. Protein immunoblotting experiments indicated that SAP precursor protein (70 kilodaltons) as well as immunoreactive SAP-like proteins of intermediate sizes (65, 50, and 31 kilodaltons) are present in most human tissues.

Amino Acid Sequence↗
PubMed1988

Porcine follistatin gene structure supports two forms of mature follistatin produced by alternative splicing.

Follistatin (FS), a novel gonadal protein which inhibits specifically the secretion of pituitary follicle stimulating hormone (FSH), has recently been isolated from porcine follicular fluid. cDNA cloning of the porcine ovarian FS precursor revealed two populations of cDNAs which differed at the 3'-region of the open reading frames; one population encodes a precursor of 317 amino acids while the other encodes another precursor having the same 317 amino acids, but with an additional 27 amino acids at the carboxy-terminal. Herein, we report the cloning of the porcine FS gene whose DNA structure reveals that the two populations of mRNA are generated by alternative splicing. In addition, restriction endonuclease mapping and DNA sequencing show that the FS gene is approximately 6 Kb long and consists of six exons separated by five introns. The first exon encodes the putative signal sequence, followed by four exons which encode the four domains of FS, three of which are highly homologous to each other. The last exon encodes the extra 27-amino acid carboxy-terminal domain of the 344-residued precursor.

Amino Acid Sequence↗
PubMed1988

Purification and characterization of the fructose-inducible HPr-like protein, FPr, and the fructose-specific enzyme III of the phosphoenolpyruvate: sugar phosphotransferase system of Salmonella typhimurium.

The proteins comprising the fructose-specific phosphoenolpyruvate:sugar phosphotransferase system were investigated using a strain of Salmonella typhimurium which lacks the general phosphotransferase system proteins, HPr and Enzyme I, synthesizes the fructose phosphotransferase system proteins, FPr, Enzyme IIfru, Enzyme IIIfru, and fructose-1-phosphate kinase, constitutively, and expresses the Enzyme I-like protein Enzyme I. Enzyme I activity was found in the cytoplasmic fraction, Enzyme IIfru in the membrane fraction, and FPr and Enzyme IIIfru activities were distributed between the two fractions. Extraction of membranes with butanol and urea led to quantitative release of the membrane-associated Enzyme IIIfru and FPr activities, while Enzyme IIfru remained with the membranes. FPr was purified to homogeneity using ion exchange chromatography, gel filtration, and reversed phase high pressure liquid chromatography (HPLC), and its amino acid composition and N-terminal sequence were determined. A complex of FPr and Enzyme IIIfru (Mr 50,000) was also purified to near homogeneity using ion exchange chromatography, gel filtration, and chromatography on hydroxylapatite. When the purified complex was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was visualized as two protein bands with mobilities corresponding to molecular weights of about 40,000 (Enzyme IIIfru) and 9,000 (FPr). Neither the FPr and Enzyme IIIfru activities nor the proteins represented by these two bands separated during the above chromatography steps or using any of several other techniques, including reversed phase HPLC, indicating a very tight association. Active Enzyme IIIfru free of FPr was never isolated or observed. The proteins could be separated in denatured form by gel filtration in the presence of guanidine HCl or urea. Free FPr and the FPr-Enzyme IIIfru complex were characterized, and the properties of free and complexed FPr were compared to those of HPr.

Bacterial Proteins↗
PubMed1988

cDNA clones coding for the structural subunit of a chicken brain nicotinic acetylcholine receptor.

Nicotinic acetylcholine receptors (AChRs) immunoaffinity-purified from brains are composed of only two kinds of subunits rather than the four kinds present in muscle-type AChRs. Here we report the N-terminal protein sequences of the structural subunits of AChRs from rat and chicken brains and the cloning of full-length cDNAs for the chicken brain AChR structural subunit. Previously, the N-terminal amino acid sequence of the ACh-binding subunit of AChR immunoaffinity-purified from rat brain was shown to correspond to the cDNA alpha 4. Thus, cDNA sequences are now known for both of the subunits that form one AChR subtype in vivo.

Amino Acid Sequence↗
PubMed1988

Primary structure of the human follistatin precursor and its genomic organization.

Follistatin is a single-chain gonadal protein that specifically inhibits follicle-stimulating hormone release. By use of the recently characterized porcine follistatin cDNA as a probe to screen a human testis cDNA library and a genomic library, the structure of the complete human follistatin precursor as well as its genomic organization have been determined. Three of eight cDNA clones that were sequenced predicted a precursor with 344 amino acids, whereas the remaining five cDNA clones encoded a 317 amino acid precursor, resulting from alternative splicing of the precursor mRNA. Mature follistatins contain four contiguous domains that are encoded by precisely separated exons; three of the domains are highly similar to each other, as well as to human epidermal growth factor and human pancreatic secretory trypsin inhibitor. The genomic organization of the human follistatin is similar to that of the human epidermal growth factor gene and thus supports the notion of exon shuffling during evolution.

Adult↗
PubMed1988

Isolation and structure of corticostatin peptides from rabbit fetal and adult lung.

A 34-amino acid peptide and three other structurally related peptides were isolated from rabbit fetal and adult lung. These cationic arginine- and cysteine-rich peptides inhibit corticotropin (ACTH)-stimulated rat adrenal cell corticosterone production. The peptide was called corticostatin (CSI). CSI was purified by reverse-phase HPLC and was shown to be homogenous from its amino acid analysis. Its sequence was determined on a gas-phase sequenator. The structure of CSI is Gly-Ile-Cys-Ala-Cys-Arg-Arg-Arg-Phe-Cys-Pro-Asn-Ser-Glu-Arg-Phe-Ser-Gly- Tyr-Cys - Arg-Val-Asn-Gly-Ala-Arg-Tyr-Val-Arg-Cys-Cys-Ser-Arg-Arg. CSI was found to markedly inhibit ACTH-stimulated corticosterone production by rat adrenal cells in vitro but did not affect basal levels. CSI did not affect the stimulation of aldosterone synthesis by angiotensin II in rat zona glomerulosa cells but it did suppress ACTH-stimulated aldosterone synthesis in whole adrenal cells, demonstrating that CSI is a specific inhibitor of ACTH-stimulated corticosteroid synthesis. The minimum effective concentration of CSI inhibiting ACTH-stimulated (33 pM) corticosterone production was 5 nM (20 ng/ml), the ED50 (50% effective dose) was 25 nM and steroidogenesis was completely inhibited at concentrations greater than 500 nM (2 micrograms/ml).

Adrenal Glands↗
PubMed1987

The major erythrotropin of bovine Cohn fraction V has the N-terminal sequence of insulin-like growth factor II with isoleucine at position 35.

The major erythrotropin-like factor of bovine Cohn Fraction V has been isolated from commercial albumin preparations by reversed-phase HPLC. The N-terminal sequence of the major fraction with erythrotropin-like activity is practically identical to the sequence of bovine insulin-like growth factor II. Within the first 45 amino acids, the only difference was the presence of an isoleucine instead of a serine at amino acid 35. This substitution may affect the immunoreactivity of this peptide using antibodies against bovine or human insulin-like growth factor II.

Amino Acid Sequence↗
PubMed1987

Follistatin specifically inhibits pituitary follicle stimulating hormone release in vitro.

Two forms of purified follistatin, a single-chain polypeptide of mol wt 35,000 (35 Kd) protein, and a related molecule of mol wt 32,000 (32 Kd), which differs from the 35 Kd form in glycosylation or carboxyl terminal truncation, specifically inhibit the release of immunoreactive FSH by primary cultures of rat pituitary cells. Both forms of follistatin and inhibin-A give similar dose-response curves, with identical slopes and maximal effects, suggesting that they may all act through the same mechanism on the pituitary cells. The median effective dose (ED50) of each of the follistatins is 6.2-7.3 ng/ml (1.8 x 10(-10) M), which corresponds to approximately 1/3 of the potency of inhibin. The effect of 35 Kd or 32 Kd follistatin is highly specific for suppressing the release of immunoreactive FSH since there is no demonstrable concomitant effect on the secretion of other pituitary hormones. The effect of follistatins, like that of inhibins, is different from that of the hypothalamic hypophysiotropic factors, requiring greater than or equal to 18 h of incubation in a pituitary monolayer culture system to demonstrate. Coincubation of inhibin and follistatin shows an additive effect in the suppression of FSH release. Pituitary cells exposed to follistatin have significantly less depletion of intracellular FSH (0.01) than those treated with inhibin, indicating that follistatin may act primarily on the suppression of FSH release rather than on both release and synthesis of FSH, as is the case with inhibin.

Animals↗
PubMed1987

A new prosomatostatin-derived peptide reveals a pattern for prohormone cleavage at monobasic sites.

Cleavage of the peptide bonds of preprosomatostatin at basic residues near the carboxyl terminus yields somatostatin-14, somatostatin-28, and somatostatin-28 (1-12). However, little is known about the molecular forms derived from the amino terminal portion of the precursor, even though this part of the prohormone is highly conserved through evolution. By using an antibody against the amino terminus of prosomatostatin, a decapeptide with the structure Ala-Pro-Ser-Asp-Pro-Arg-Leu-Arg-Gln-Phe, corresponding to preprosomatostatin (25-34), was isolated from the endocrine portion of the rat stomach, the gastric antrum. The antral decapeptide may represent a bioactive product generated from prosomatostatin after a monobasic cleavage similar to that involved in the formation of somatostatin-28. In fact, a monobasic cleavage requires two basic residues and a domain containing nonpolar amino acids such as alanine or leucine, or both.

Amino Acid Sequence↗
PubMed1987

Sequence analysis, cellular localization, and expression of a neuroretina adhesion and cell survival molecule.

A cDNA for purpurin, a secreted 20,000 dalton neural retina cell adhesion and survival protein, has been sequenced and expressed in mammalian cells. Purpurin mRNA is found in both embryonic and adult retina, but not the brain, heart, or liver. The protein is highly concentrated in the neural retina between the pigmented epithelium and the outer segments of the photoreceptor cells; it is synthesized by photoreceptor cells. The predicted purpurin sequence contains 196 residues, has approximately 50% sequence homology with serum retinol binding protein, and is a member of the alpha-2 mu-globulin superfamily. Purpurin binds retinol and may play a major role in retinol transport across the interphotoreceptor cell matrix.

Amino Acid Sequence↗
PubMed1987

Neuronal nicotinic acetylcholine receptor beta-subunit is coded for by the cDNA clone alpha 4.

Acetylcholine receptors (AChRs) with high affinity for nicotine but no affinity for alpha-bungarotoxin, which have been purified from rat and chicken brains by immuno-affinity chromatography, consist of two types of subunits, alpha and beta. The beta-subunits form the ACh binding sites. Putative nicotinic AChR subunit cDNAs alpha 3 and alpha 4 have been identified by screening cDNA libraries prepared from rat PC12 cells and rat brain with cDNA probes encoding the mouse muscle AChR alpha-subunit. Here we determine the amino-terminal amino acid sequence of the rat brain AChR beta-subunit by protein microsequencing to be the same as amino acid residues 27-43 of the protein which could be coded by alpha 4. Further, we present evidence consistent with a subunit stoichiometry of alpha 3 beta 2 for this neuronal nicotinic AChR.

Amino Acid Sequence↗
PubMed1987

Amino-terminal sequence of a large form of basic fibroblast growth factor isolated from human benign prostatic hyperplastic tissue.

Homogenization of human benign prostatic hyperplastic tissue in high ionic strength alkaline buffer containing protease inhibitors resulted in the isolation of a 17,400 molecular weight growth factor. When tissue was homogenized in ammonium sulfate at pH 4.5 without protease inhibitors a smaller, 16,600 dalton, growth factor was isolated. Both growth factors reacted with antisera against synthetic peptides whose sequences corresponded to the amino-terminal (1-12), Internal (33-43) and carboxyl-terminal (135-145) portions of basic fibroblast growth factor (bFGF). This suggested that the smaller growth factor was not a truncated form of (1-146) bFGF and that the larger growth factor may contain additional sequences. Amino-terminal sequencing showed the larger growth factor to have the sequence: Ala-Ala-Gly-Ser-Ile-Thr-Thr-Leu-Pro-Ala-Leu-Pro-Glu-Asp-Gly-Gly-Ser-Gly- Ala-Phe-Pro-. These results show that the larger growth factor is an 8 amino acid extended from of (1-146) bFGF and it is likely that the smaller growth factor is a proteolytic cleavage product of the larger growth factor produced during the extraction procedure.

Amino Acid Sequence↗
PubMed1987

Immunohistochemical detection of inhibin in the gonad.

Antiserum to inhibin was produced in rabbits by immunization with a synthetic [Tyr30]alpha-chain(1-30)NH2 fragment of porcine inhibin coupled to bovine serum albumin, and the elicited antiserum was used in conjunction with the avidin-biotin immunoperoxidase procedure to localize inhibin-reactive cells in various rat tissue preparations. In the testes, only the Sertoli cells revealed immunoreactivity with the antiserum. Intense staining was also observed in ovarian follicular granulosa cells but not in the theca layer outside the basement membrane. In addition, the luteal cells in the corpus luteum were also stained by the antiserum. The positive staining in the gonadal tissues could be blocked completely by pre-adsorbing the serum with either the synthetic peptide or native inhibin. Immunostaining was not detected in brain, pituitary, thymus, stomach, pancreas, kidney and adrenal section, thus confirming that inhibin is a polypeptide originating only from specific cells of the gonad.

Animals↗