| 1691683 |
Analysis of the topological changes induced on cells exposed to adhesive or mechanical stimuli |
10.1007/BF02989690. |
Cell Biophys |
Analysis of the topological changes induced on cells exposed to adhesive or mechanical stimuli
Abstract
- Fluorescent probes are widely used to study cell structure and function. However, few reports were devoted to a quantitative analysis of the intracellular distribution of fluorescent markers. In the present work, we describe the topographical changes of surface and cytoskeletal markers on individual cells subjected to adhesive or mechanical interaction. Conjugates were prepared with a cytotoxic T-lymphocyte clone and target cells. Specific antigens, membrane phospholipids, surface glycoconjugates, and polymerized actin were labeled with fluorescent antibodies or biochemical probes. The analysis of fluorescence distributions in conjugates demonstrated a selective reorganization of the plasma membrane with a gathering of some molecular species in the intercellular adhesion area. Furthermore, individual phagocytic cells were sucked into glass micropipets, then stained with fluorescent phallacidin to analyze the effect of mechanical efforts on the cytoskeleton organization. The concentration of polymerized actin was found to be similar in mechanically-induced protrusions and whole cells. It is concluded that adhesive interactions may result in marked cell polarization and formation of membrane zones with a particular biochemical composition. The submembranar cytoskeleton might play a role in this process.
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| 1692292 |
A genetic polymorphism in a functional domain of human pregnancy zone protein: the bait region. Genomic structure of the bait domains of human pregnancy zone protein and alpha 2 macroglobulin. |
10.1016/0014-5793(90)80226-9 |
FEBS Lett. |
A genetic polymorphism in a functional domain of human pregnancy zone protein: the bait region. Genomic structure of the bait domains of human pregnancy zone protein and alpha 2 macroglobulin.
Abstract
- Genomic clones containing the exons coding for the bait domain of human pregnancy zone protein and alpha 2 macroglobulin were isolated and fragments containing the bait exons were sequenced. It is shown that the bait domains of both alpha 2 macroglobulin and pregnancy zone protein are encoded by two exons, with conserved exon/intron boundaries. A genetic polymorphism showing either a Met or a Val residue as the sixth amino acid of the pregnancy zone protein bait domain was detected with the rare Met allele showing a gene frequency of 0.065.
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| 1707161 |
Sequence polymorphism in the human alpha-2-macroglobulin (A2M) gene |
10.1093/nar/19.1.198-a. |
Nucleic Acids Res |
Sequence polymorphism in the human alpha-2-macroglobulin (A2M) gene
Abstract
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| 1709010 |
Cloning and sequencing of human FSH receptor cDNA. |
10.1016/0006-291x(91)91682-3 |
Biochem. Biophys. Res. Commun. |
Cloning and sequencing of human FSH receptor cDNA.
Abstract
- We have isolated and sequenced a cDNA encoding the follicle stimulating hormone (FSH) receptor. The deduced amino acid sequence (678 residues) containing seven putative transmembrane segments which displays sequence similarity to G protein-coupled receptors. The receptor consists of 359 residue extracellular domain which contains four N-linked glycosylation sites. While the protein is 89% identical overall with the previously cloned rat FSH receptor, the most highly conserved regions are the putative transmembrane segments (95% similarity).
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| 1711172 |
Intrathecal somatostatin, somatostatin analogs, substance P analog and dynorphin A cause comparable neurotoxicity in rats |
10.1016/0306-4522(90)90259-7. |
Neuroscience |
Intrathecal somatostatin, somatostatin analogs, substance P analog and dynorphin A cause comparable neurotoxicity in rats
Abstract
- Rats chronically implanted with intrathecal catheters received intrathecal injections (10 microliters followed by 10 microliters saline flush) of either saline (n = 5), somatostatin (100 micrograms, n = 10), the somatostatin analog BIM 23003 (100 micrograms, n = 5), the somatostatin analog SMS 201-995 (100 micrograms, n = 5), the substance P analog D-Pro2, D-Trp7,9 SP (10 micrograms, n = 10), or dynorphin A (1-17) (20 nmol, n = 8). These doses (somatostatin, substance P and dynorphin A) were selected based on previous studies in which they caused significant motor deficits. Effects on thermal cutaneous nociception, behavior, motor function and spinal cord histopathology were evaluated. All peptides caused severe neurotoxicity, evidenced by flaccid hind leg paralysis and lumbar spinal neuronal degeneration, which was accompanied by an inflammatory reaction in meninges and spinal gray matter. Histopathological changes had developed within 24 h after injection of somatostatin, substance P analog and dynorphin A, showing mild to severe neuronal degeneration and mild inflammatory responses in spinal cord and meninges. Significant antinociceptive effects, due to severe neurotoxic effects, were only observed following intrathecal injection of SMS 201-995 and the substance P analog. Potential neurotoxic mechanisms of the different peptides are discussed.
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| 1711844 |
Analysis of the human type I insulin-like growth factor receptor promoter region. |
10.1016/0006-291x(91)90654-p |
Biochem. Biophys. Res. Commun. |
Analysis of the human type I insulin-like growth factor receptor promoter region.
Abstract
- We isolated genomic fragments containing the 5' region of the human type I insulin-like growth factor receptor gene. A unique transcription start site was identified, defining a 1038 bp 5'-untranslated region. No TATA or CCAAT elements were identified in the proximal 480 nucleotides of 5'-flanking region. The region surrounding the transcription start site was similar to a recently described "initiator" sequence. The 5'-flanking and 5'-untranslated regions were highly GC-rich, with numerous potential Sp1 binding sites. A potential AP-2 binding site was identified in the 5'-flanking region and a potential thyroid response element was identified in the 5'-untranslated region. The 5' region of the human gene was very similar to that of the rat gene, with conservation of many of the potential regulatory elements.
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| 1718267 |
Molecular cloning, structural characterization and functional expression of the human substance P receptor |
10.1016/0006-291x(91)91704-g. |
Biochem Biophys Res Commun |
Molecular cloning, structural characterization and functional expression of the human substance P receptor
Abstract
- A cDNA encoding the human substance P receptor (SPR) was isolated and the primary structure of the protein was deduced by nucleotide sequence analysis. This SPR consists of 407 residues and is a member of the G-protein coupled receptor superfamily. Comparison of rat and human SPR sequences demonstrated a 94.5% identity. The receptor was expressed in a COS-7 cell line and displayed a Kd for Tyr-1-SP binding of 0.24 nM. Ligand displacement by naturally occurring tachykinin peptides was SP much greater than neurokinin A greater than neurokinin B. SP stimulation of transfected cells resulted in a rapid and transient inositol 1,4,5-trisphosphate response. RNA blot hybridization and solution hybridization demonstrated that SPR mRNA was about 4.5 Kb in size, and was expressed in IM-9 lymphoblast and U373-MG astrocytoma cells, as well as in spinal cord and lung but not in liver.
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| 1718270 |
Isolation and expression of a guanylate cyclase-coupled heat stable enterotoxin receptor cDNA from a human colonic cell line. |
10.1016/0006-291x(91)91736-v |
Biochem. Biophys. Res. Commun. |
Isolation and expression of a guanylate cyclase-coupled heat stable enterotoxin receptor cDNA from a human colonic cell line.
Abstract
- Heat stable enterotoxins (STs) are low molecular-weight peptides secreted by enterotoxigenic bacteria. One type of these enterotoxins (STa) induces intestinal secretion leading to acute diarrhea by binding to a membrane form of guanylate cyclase. We have isolated a cDNA from a human colonic cell line, T84, encoding for a guanylate cyclase-coupled enterotoxin receptor (STaR). The predicted amino acid sequence of the human STa receptor is 81% identical with the previously cloned enterotoxin receptor (GC-C) from rat intestine. COS-7 cells transiently transfected with the cloned cDNA expressed specific concentration-dependent response to STa as measured by cyclic GMP accumulation and is about 20 times more sensitive to the stimulation by STa than has been shown for GC-C.
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| 1730625 |
An Arg for Gly substitution at position 31 in the insulin receptor, linked to insulin resistance, inhibits receptor processing and transport |
None |
J Biol Chem |
An Arg for Gly substitution at position 31 in the insulin receptor, linked to insulin resistance, inhibits receptor processing and transport
Abstract
- In a patient with Leprechaunism, we have characterized a new mutation in the insulin receptor substituting Arg for Gly at position 31. The proband, the mother, and the maternal grandfather were heterozygous for the mutation. Fibroblasts of the proband show a strongly reduced number of high affinity insulin receptors on the cell surface, whereas fibroblasts of the healthy mother and grandfather show moderately reduced insulin receptor numbers. In the other family members neither the binding defect nor the Arg31 mutation was found. The Arg31-mutant receptor was overexpressed in Chinese hamster ovary cells. In these cells the mutant alpha beta-proreceptor was not proteolytically cleaved and no transport to the cell surface took place. The proreceptor was unable to bind insulin and to undergo autophosphorylation. In addition, the proreceptor was not recognized by monoclonal antibodies directed against conformation-dependent epitopes. These findings suggest that the Gly31 to Arg31 mutant is involved in the insulin receptor dysfunction seen in the Leprechaun patient. The mutation seems to alter the conformation of the receptor in such way that the transport of the proreceptor to the Golgi compartment, where proteolytical processing occurs, is inhibited.
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| 1733929 |
Isolation and characterization of a novel class of plant antimicrobial peptides form Mirabilis jalapa L. seeds |
None |
J Biol Chem |
Isolation and characterization of a novel class of plant antimicrobial peptides form Mirabilis jalapa L. seeds
Abstract
- We have isolated from seeds of Mirabilis jalapa L. two antimicrobial peptides, designated Mj-AMP1 and Mj-AMP2, respectively. These peptides are highly basic and consist of 37 and 36 residues for Mj-AMP1 and Mj-AMP2, respectively. Both peptides contain three disulfide bridges and differ from one another only by 4 amino acids. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the reduced and unreduced peptides suggests that the peptides associate into dimers in their native form. The Mj-AMPs exhibit a broad spectrum of antifungal activity since they are active against all 13 tested plant pathogenic fungi. Concentrations required for 50% inhibition of fungal growth vary from 6 to 300 micrograms/ml for Mj-AMP1 and from 0.5 to 20 micrograms/ml for Mj-AMP2. These peptides were also active on two tested Gram-positive bacteria but were apparently nontoxic for Gram-negative bacteria and cultured human cells. Although the Mj-AMPs show sequence similarity to mu-agatoxins, a class of insecticidal neurotoxic peptides isolated from the venom of spiders, they do not affect pulse transmission in insect nerves.
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| 1737015 |
Correlation of tryptophan fluorescence intensity decay parameters with 1H NMR-determined rotamer conformations: tryptophan2oxytocin |
10.1021/bi00121a002. |
Biochemistry |
Correlation of tryptophan fluorescence intensity decay parameters with 1H NMR-determined rotamer conformations: tryptophan2oxytocin
Abstract
- While the fluorescence decay kinetics of tyrosine model compounds Laws, W. R., Ross, J. B. A., Wyssbrod, H. R., Beechem, J. M., Brand, L., & Sutherland, J. C. (1986) Biochemistry 25, 599-607 and the tyrosine residue in oxytocin Ross, J. B. A., Laws, W. R., Buku, A., Sutherland, J. C., & Wyssbrod, H. R. (1986) Biochemistry 25, 607-612 can be explained in terms of heterogeneity derived from the three ground-state chi 1 rotamers, a similar correlation has yet to be directly observed for a tryptophan residue. In addition, the asymmetric indole ring might also lead to heterogeneity from chi 2 rotations. In this paper, the time-resolved and steady-state fluorescence properties of tryptophan2oxytocin at pH 3 are presented and compared with 1H NMR results. According to the unrestricted analyses of individual fluorescence decay curves taken as a function of emission wavelength and a global analysis of these decay curves for common emission wavelength-independent decay constants, only three exponential terms are required. In addition, the preexponential weighting factors (amplitudes) have the same relative relationship (weights) as the 1H NMR-determined chi 1 rotamer populations of the indole side chain. 15N was used in heteronuclear coupling experiments to confirm the rotamer assignments. Inclusion of a linked function restricting the decay amplitudes to the chi 1 rotamer populations in the individual decay curve analyses and in the global analysis confirms this correlation. According to qualitative nuclear Overhauser data, there are two chi 2 populations. Depending upon the degree of correlation between chi 2 and chi 1, there may be from three to six side-chain conformations for the tryptophan residue. The combined fluorescence and NMR results are consistent with a rotamer model in which either (i) the chi 2 rotations are fast compared to the fluorescence intensity decay of the tryptophan residue, (ii) environmental factors affecting fluorescence intensity decay properties are dominated by chi 1 interactions, or (iii) the chi 2 and chi 1 rotations are highly correlated.
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| 1744108 |
Bombinin-like peptides with antimicrobial activity from skin secretions of the Asian toad, Bombina orientalis |
None |
J Biol Chem |
Bombinin-like peptides with antimicrobial activity from skin secretions of the Asian toad, Bombina orientalis
Abstract
- The structures and hemolytic and bactericidal activities of three bombinin-like peptides, or BLP-1-3, from the skin of Bombina orientalis are described. The peptides were isolated from the skin of B. orientalis and sequenced by tandem mass spectrometry and are amphipathic, cationic peptides of 25-27 amino acids in length. The sequence of the most abundant member (BLP-1) is: Gly-Ile-Gly-Ala-Ser-Ile-Leu-Ser-Ala-Gly-Lys-Ser-Ala-Leu-Lys-Gly-Leu- Ala-Lys-Gly-Leu-Ala-Glu-His-Phe-Ala-Asn-NH2. All three peptides were found to share considerable, but not complete, homology with bombinin, an antimicrobial, hemolytic peptide first isolated by Michl and Csordas (Csordas, A., and Michl, A. (1970) Monatsh. Chem. 101, 182-189) from the skin of Bombina variegata. The BLPs have been assayed for antibiotic and hemolytic activity and found to be more potent than magainin 2 (a related antimicrobial peptide from Xenopus laevis) in their ability to kill bacteria. However, no significant hemolytic activity was found for these peptides which suggests a selectivity for prokaryotic over eukaryotic membranes. The molecular basis for antibacterial activity is presumed to be due to their predicted amphipathic alpha-helical structures which is supported by circular dichroism measurements that found significant helical content (63-69% alpha-helix) in 40% trifluoroethanol. Last, a cDNA library was constructed from the skin of B. orientalis and screened with an oligonucleotide probe complementary to the COOH terminus of BLP-1. Several clones were isolated and sequenced that encode BLP-1 and BLP-3, as well as an additional peptide (BLP-4) that differs by two amino acid substitutions from BLP-3.
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| 1744118 |
The cyclophilin multigene family of peptidyl-prolyl isomerases. Characterization of three separate human isoforms. |
10.1016/s0021-9258(18)54484-7 |
J. Biol. Chem. |
The cyclophilin multigene family of peptidyl-prolyl isomerases. Characterization of three separate human isoforms.
Abstract
- Cyclophilin (CyP), a major cytosolic protein possessing peptidyl-prolyl cis-trans isomerase activity, has been implicated as the specific receptor of the immunosuppressive drug cyclosporin A (CsA). To identify other potential CsA receptors related to CyP, two human cDNA libraries were screened under low stringency conditions using human CyP cDNA (encoding hCyP1) as a probe. Two cDNAs were identified which encode distinct proteins related to human hCyP1. These two novel proteins, designated hCyP2 and hCyP3, share 65 and 76% amino acid sequence homology with hCyP1, respectively. Both hCyP2 and hCyP3 contain NH2-terminal hydrophobic extensions of 32 and 42 amino acids, respectively. Protein-specific antibodies revealed the predominant association of hCyP2 and hCyP3 with membranes and subcellular organelles, which suggests that the amino-terminal leader sequences of the two CyP isoforms may act as signal peptides. In contrast to the
Results with hCyP1, Southern blot analysis indicated that both hCyP2 and hCyP3 gene sequences are represented infrequently in the human genome. Northern and Western blot analysis showed that the distribution of mRNA and proteins of the three hCyPs in differing tissues and cell types was similar. Each hCyP protein was expressed in Escherichia coli, purified, and shown to be an active peptidyl-prolyl isomerase. Substrate specificity was examined with 11 synthetic peptides (Suc-Xaa-Yaa-Pro-Phe-4-nitroanilide), and inhibition of the peptidyl-prolyl isomerase activities associated with hCyP1, hCyP2, and hCyP3 was studied with CsA, MeAla6-CsA and MeBm2t1-CsA. From both equilibrium considerations and the
Results of kinetic characterizations it is proposed that of these three CyP proteins, hCyP1 is the most likely intracellular target for CsA.
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| 1761415 |
Structures of aureobasidins B to R |
10.7164/antibiotics.44.1187. |
J Antibiot (Tokyo) |
Structures of aureobasidins B to R
Abstract
- Structures of 17 minor forms of aureobasidins (Abs), Abs B-R, were elucidated by mass fragmentation and amino acid analysis. The fragmentation patterns by FAB-MS spectroscopy of Abs A-E seemed to follow predictable rules, so we used the rules to elucidate the 13 other Abs. All Abs consisted of eight amino acids and one hydroxy acid.
|
| 1761416 |
NMR studies of aureobasidins A and E |
10.7164/antibiotics.44.1199. |
J Antibiot (Tokyo) |
NMR studies of aureobasidins A and E
Abstract
- The 1H and 13C NMR spectra of aureobasidins A and E were analyzed by a variety of 2D NMR techniques. Two isomers of aureobasidin A existed as an equilibrium mixture in deuteriochloroform. The isomerism was associated with cis-trans rotation of the amide bond between N-methylphenylalanine and proline. Almost all of the aureobasidin E was found in deuteriochloroform as one conformer; the amide bond between beta-hydroxy-N-methylphenylalanine and proline was in the cis-conformation. Experiments with the NOE made identification of the conformation of the amide bonds of aureobasidins A and E possible.
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