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PubMed2002

Bioengineered emulsans from Acinetobacter calcoaceticusRAG-1 transposon mutants.

Transposon mutants of Acinetobacter calcoaceticus strain RAG-1 were studied in an effort to control fatty acid (FA) substitution patterns of emulsan, a bioemulsifier secreted by the organism. The disrupted genes, involved in the biosynthetic pathways of biotin, histidine, cysteine or purines, influenced the level and types of FAs incorporated into emulsan. The structural variants of emulsan generated by the transposon mutants were characterized for yield, FA content, molecular weight, and emulsification behavior when grown on a series of FAs of different chain lengths from C11 to C18. Yields of emulsan from the transposon mutants were found to be lower than the parent strain and depended on the type of FA used to supplement the growth medium. Mutants 13D (His-) and 52D (Cys-) grown on LB plus C16 or C14, respectively, exhibited enhanced emulsifying activity compared to A. calcoaceticus RAG-1. The presence and composition of long chain FAs on the polysaccharide backbone influenced emulsification behavior: particularly a high mole percentage of C16 (48%) and C18 (42%). The results provide important insight into the bioengineering of bioemulsifier-producing microorganisms and provide a path towards highly tailored novel amphipathic structures to utilize as biodegradable in environmental, biomedical, and personal care applications.

Acinetobacter calcoaceticus↗

PubMed2004

Extracellular alpha 6 integrin cleavage by urokinase-type plasminogen activator in human prostate cancer.

During human prostate cancer progression, the integrin alpha6beta1 (laminin receptor) is expressed on the cancer cell surface during invasion and in lymph node metastases. We previously identified a novel structural variant of the alpha6 integrin called alpha6p. This variant was produced on the cell surface and was missing the beta-barrel extracellular domain. Using several different concentrations of amiloride, aminobenzamidine and PAI-1 and the urokinase-type plasminogen activator (uPA) function-blocking antibody (3689), we showed that uPA, acting as a protease, is responsible for production of alpha6p. We also showed that addition of uPA in the culture media of cells that do not produce alpha6p, resulted in a dose-dependent alpha6p production. In contrast, the addition of uPA did not result in the cleavage of other integrins. Using alpha2-antiplasmin and plasmin depleted media, we observed that uPA cleaves the alpha6 integrin directly. Further, 12-o-tetradecanoyl-phorbol-13-acetate (TPA) induced the production of alpha6p, and this induction was abolished by PAI-1 but not alpha2-antiplasmin. Finally, the alpha6p integrin variant was detected in invasive human prostate carcinoma tissue indicating that this is not a tissue culture phenomenon. These data, taken together, suggest that this is a novel function of uPA, that is, to remove the beta-barrel ligand-binding domain of the integrin while preserving its heterodimer association.

Antibodies↗

PubMed2005

[The effect of immobilized fibronectin on karyotypic variability in the skin fibroblast cell subline of indian muntjac].

The numerical and structural karyotypic variability has been investigated in the Indian muntjac skin fibroblast cell subline MT on cultivating cells on the fibronectin-coated surface. In cell subline MT, cultivated on the fibronectin-coated surface for 1 and 2 days, the character of cell distribution for the chromosome number did not change. In 3, 4 and 8 days, the character of cell distribution for the chromosome number changed. These changes involve a significant decrease in frequency of cells with modal numbers of chromosomes, and an increase in frequency of cells with lower chromosome numbers. Many new additional structural variants of the karyotype (SVK) appear. The observed alterations seem to be due to both disturbances of mitotic apparatus and selection of SVK, which are more advantageous to changed culture conditions of the cell population. Detachment of cells from the fibronectin-coated surface, followed by a 1 day cultivation on a hydrophilic surface, commonly used for routine cell cultivation, does not restore the control cell distribution for the chromosome number, but cultivation in these conditions for 5 days restore control distribution. The frequency of chromosomal aberrations on cultivation on the fibronectin-coated surface for 3 and 4 days significantly increases, mainly at the expence of dicentrics (telomeric association). On prolongating the time of cultivation up to 8 days on the fibronectin-coated surface the frequency of chromosomal aberrations approaches the control value. Structural instability of chromosomes at cultivation on the fibronectin-coated surface demonstrates nonspecific reaction of "markerless" cell lines to unfavourable factors of the environment. We discuss possible reasons of differences in the character of karyotypic variability in cell lines of the Indian muntjac skin fibroblasts on cultivating on laminin and fibronectin.

Animals↗

PubMed2025

Reproductive Isolation due to Divergent Ecological Selection Is Accompanied by Vast Genomic Instability in Experimentally Evolved Yeast Populations.

Populations evolving independently in divergent environments accumulate genetic differences and potentially evolve reproductive isolation as a by-product of divergence. The speed and mechanisms underlying this process are difficult to investigate because we rarely get the opportunity to witness them in natural settings, and histories of selection and gene flow between populations are often unknown. Here, we experimentally evolved yeast for 1000 generations of evolution in both divergent and parallel environments. At regular time points during experimental evolution, we made crosses between parallel- and divergent-evolving populations to measure postzygotic reproductive isolation (gamete viability). We used whole genome population sequencing to determine the mutational load, the number and types of structural variation, and other genomic features of the parent, F1 and F2 intraspecific hybrids. We found evidence for large-scale phenotypic and genome-wide differentiation in response to divergent laboratory selection. Divergent-selected populations produced hybrids with reduced gamete viability-a classic signature of postzygotic reproductive isolation in the form of hybrid breakdown. Parallel-selected populations, on the other hand, remained more reproductively compatible (with exceptions). We found that F2 hybrid genomes contained vast genomic instability, that is, new structural variants (especially insertions, deletions and interchromosomal translocations) that were not observed in parent and F1 genomes, which is likely a result of chromosome missegregation and recombination errors in hybrid meiosis. Our results provide phenotypic and genomic evidence that partial reproductive isolation evolved due to adaptation to divergent environments, consistent with predictions of ecological speciation theory.

Reproductive Isolation↗

PubMed1998

High affinity recognition of serotonin transporter antagonists defined by species-scanning mutagenesis. An aromatic residue in transmembrane domain I dictates species-selective recognition of citalopram and mazindol.

Human and Drosophila melanogaster serotonin (5-HT) transporters (SERTs) exhibit similar 5-HT transport kinetics and can be distinguished pharmacologically by many, but not all, biogenic amine transporter antagonists. By using human and Drosophila SERT chimeras, major determinants of potencies of two transporter antagonists, mazindol and citalopram, were tracked to the amino-terminal domains encompassing transmembrane domains I and II. Species-scanning mutagenesis, whereby amino acid substitutions are made switching residues from one species to another, was employed on the eight amino acids that differ between human and Drosophila SERTs in this region, and antagonist potencies were reassessed in 5-HT uptake assays. A single mutation in transmembrane domain I of human SERT, Y95F, shifted both citalopram and mazindol to Drosophila SERT-like potencies. Strikingly, these potency changes were in opposite directions suggesting Tyr95 contributes both positive and negative determinants of antagonist potency. To gain insight into how the Y95F mutant might influence mazindol potency, we determined how structural variants of mazindol responded to the mutation. Our studies demonstrate the importance of the hydroxyl group on the heterocyclic nucleus of mazindol for maintaining species-selective recognition of mazindol and suggest that transmembrane domain I participates in the formation of antagonist-binding sites for amine transporters.

Animals↗

PubMed1999

Sugar printing rheumatic diseases: a potential method for disease differentiation using immunoglobulin G oligosaccharides.

OBJECTIVE: To look for oligosaccharide structural variants of IgG that may be unique to specific rheumatic diseases. METHODS: Using normal-phase high-performance liquid chromatography technology, a comparison was made of the oligosaccharide pools released from serum IgG from patients with systemic lupus erythematosus (SLE) (n = 10), ankylosing spondylitis (AS) (n = 10), primary Sjögren's syndrome (n = 6), juvenile chronic arthritis (JCA) (n = 13), psoriatic arthritis (n = 9), rheumatoid arthritis (RA) (n = 5), and healthy control individuals (n = 19). RESULTS: The oligosaccharide pools were resolved into 13 peaks and the relative proportions of the peaks in each disease group was significantly different from that in healthy controls (P < 0.0001-0.05). A characteristic serum IgG oligosaccharide profile, or sugar print, for each of the rheumatic diseases was found. The sugar prints exhibited a range of glycosylation patterns whereby all RA (P < 0.0001) and JCA (P < 0.006) patients had predominantly agalactosyl structures, while SLE (P < 0.03-0.0001) and AS (P < 0.025-0.0001) patients had predominantly digalactosyl structures. CONCLUSION: The data suggest that each disease is associated with a specific mechanism that gives rise to alterations in the normal glycosylation pattern of IgG. Sugar printing of IgG is therefore a potential means for the differentiation of rheumatic diseases and may provide insight into disease pathogenesis.

Adult↗

PubMed2003

Over-the-barrier transition state analogues and crystal structure with Mycobacterium tuberculosis purine nucleoside phosphorylase.

Stable chemical analogues of enzymatic transition states are imperfect mimics since they lack the partial bond character of the transition state. We synthesized structural variants of the Immucillins as transition state analogues for purine nucleoside phosphorylase and characterized them with the enzyme from Mycobacterium tuberculosis (MtPNP). PNPs form transition states with ribooxacarbenium ion character and catalyze nucleophilic displacement reactions by migration of the cationic ribooxacarbenium carbon between the enzymatically immobilized purine and phosphate nucleophiles. As bond-breaking progresses, carbocation character builds on the ribosyl group, the distance between the purine and the carbocation increases, and the distance between carbocation and phosphate anion decreases. Transition state analogues were produced with carbocation character and increased distance between the ribooxacarbenium ion and the purine mimics by incorporating a methylene bridge between these groups. Immucillin-H (ImmH), DADMe-ImmH, and DADMe-ImmG mimic the transition state of MtPNP and are slow-onset, tight-binding inhibitors of MtPNP with equilibrium dissociation constants of 650, 42, and 24 pM. Crystal structures of MtPNP complexes with ImmH and DADMe-ImmH reveal an ion-pair between the inhibitor cation and the nucleophilic phosphoryl anion. The stronger ion-pair (2.7 A) is found with DADMe-ImmH. The position of bound ImmH resembles the substrate side of the transition state barrier, and DADMe-ImmH more closely resembles the product side of the barrier. The ability to probe both substrate and product sides of the transition state barrier provides expanded opportunities to explore transition state analogue design in N-ribosyltransferases. This approach has resulted in the highest affinity transition state analogues known for MtPNP.

Catalytic Domain↗

PubMed1999

Structural aspects of the association of FcepsilonRI with detergent-resistant membranes.

We recently showed that aggregation of the high affinity IgE receptor on mast cells, FcepsilonRI, causes this immunoreceptor to associate rapidly with specialized regions of the plasma membrane, where it is phosphorylated by the tyrosine kinase Lyn. In this study, we further characterize the detergent sensitivity of this association on rat basophilic leukemia-2H3 mast cells, and we compare the capacity of structural variants of FcepsilonRI and other receptors to undergo this association. We show that this interaction is not mediated by the beta subunit of the receptor or the cytoplasmic tail of the gamma subunit, both of which are involved in signaling. Using chimeric receptor constructs, we found that the extracellular segment of the FcepsilonRI alpha subunit was not sufficient to mediate this association, implicating FcepsilonRI alpha and/or gamma transmembrane segments. To determine the specificity of this interaction, we compared the association of several other receptors. Interleukin-1 type I receptors on Chinese hamster ovary cells and alpha4 integrins on rat basophilic leukemia cells showed little or no association with isolated membrane domains, both before and after aggregation on the cells. In contrast, interleukin-2 receptor alpha (Tac) on Chinese hamster ovary cells exhibited aggregation-dependent membrane domain association similar to FcepsilonRI. These results provide insights into the structural basis and selectivity of lipid-mediated interactions between certain transmembrane receptors and detergent-resistant membranes.

Animals↗

PubMed1997

Enlarged acetabular labra in the Pima Indians.

OBJECTIVE: To report the descriptive epidemiology of acetabular labral enlargement and analyze associations of other variables with this variant. METHODS: Pelvis radiographs from 761 Pima Indians aged > or = 45 years enrolled in a population based study were read by Kellgren-Lawrence global and individual radiographic features grading scales for osteoarthritis (OA) at separate settings. In total, 722 radiographs remained eligible for this study after excluding 12 unreadable radiographs and 27 cases of radiographic hip OA (Kellgren-Lawrence grade > or = 2). Enlarged acetabular labra were recorded during readings of individual radiographic features. RESULTS: Enlarged acetabular labra were present in 16% of study participants without OA and were significantly associated with female sex, but not with the variables age, body mass index, clinical hip joint involvement, diabetes, or serum insulin concentrations. CONCLUSION: Acetabular labral enlargement is common in the Pima Indians, and although not in excess of other reported acetabular margin anomalies, it differs in appearance and is not associated with age. Recognition of this structural variant is important because it can mimic fractures or osteophytes.

Acetabulum↗

PubMed2002

Gonadotropin-releasing hormone (GnRH): from fish to mammalian brains.

This work deals with a family of neuropeptides, gonadotropin-releasing hormone (GnRH), that play a key role in the development and maintenance of reproductive function in vertebrates. 2. Until now, a total of 16 GnRH structural variants have been isolated and characterized from vertebrate and protochordate nervous tissue. All vertebrate species already investigated have at least two GnRH forms coexisting in the central nervous system. However, it is now well accepted that three forms of GnRH in early and late evolved bony fishes are present. 3. In these cases, cGnRH-II is expressed by midbrain neurons, a species-specific GnRH is present mainly in the preoptic area and the hypothalamus, and sGnRH is localized in the terminal nerve ganglion (TNG). In this context it is possible to think that three GnRH forms and three GnRH receptor (GnRH-R) subtypes are expressed in the central nervous system of a given species. 4. Then it is possible to propose three different GnRH lineages expressed by distinct brain areas in vertebrates: (1) the conserved cGnRH-II or mesencephalic lineage; or (2) the hypothalamic or "releasing" lineage whose primary structure has diverged by point mutations (mGnRH and its orthologous forms: hrGnRH, wfGnRH, cfGnRH, sbGnRH, and pjGnRH); and (3) the telencephalic sGnRH form. Also different GnRH nomenclatures are discussed.

Animals↗

PubMed2025

Spinocerebellar Ataxia 27 A with Episodic Ataxia: Case Series of Fibroblast Growth Factor 14 (FGF14) Microdeletions.

Spinocerebellar ataxia 27 A (SCA27A) is a form of progressive cerebellar ataxia due to pathogenic variants in the Fibroblast Growth Factor 14 (FGF14) gene. The objective of this paper is to characterise the clinical spectrum of SCA27A microdeletions (> 50 bp, <2Mbp), and report two novel cases. Literature searches of PubMed, OMIM and ClinVar were carried out. We identified SCA27A microdeletions in 32 cases across 11 families. The phenotypic presentation is: 75% (24/32) nystagmus, 46% (15/32) ataxia, 21% (7/32) episodic ataxia, 21% (7/32) tremor, 15% (5/32) dysarthria, 34% (11/32) learning disability, 28% (8/32) neuropsychiatric disease. The presentation is variable within and between families. Episodic symptoms, nystagmus, learning disability and neuropsychiatric symptoms occur at an earlier age. Patient 1 represents the first case with a 58 kb FGF14 deletion who presented with a paroxysmal movement disorder. Patient 2 carries a 545 kb deletion and developed episodic ataxia and trigeminal neuralgia, a novel feature not previously described in this cohort. We report two cases of heterozygous FGF14 microdeletions: Patient 1 (58 kb) and Patient 2 (545 kb), expanding the phenotypic spectrum of FGF14 structural variants to 32 cases across 11 families. We review potential mechanism from pre-clinical studies relating FGF14 haploinsufficiency to cerebellar, cognitive, neuropsychiatric symptoms, as well as trigeminal neuralgia. We propose the hypothesis that the episodic symptoms in SCA27A align with the molecular pathology of a channelopathy and propose management strategies based on this insight.

Humans↗

PubMed2025

A vision of how low-coverage sequence data should contribute to genetic evaluation in the future.

Low-coverage sequencing refers to sequencing DNA of individuals to a low depth of coverage (e.g., 0.5X) and imputing that sequence to a genomic sequence based on reference haplotypes from individuals sequenced to a high depth of coverage (e.g., ≥10X). It has been proposed as an alternative to genotyping by Single-nucleotide polymorphisms (SNP) arrays. At least one commercial product based on it is available for agricultural species. Concerns limiting adoption in its current form are: 1) the cost of storing the huge volume of data it generates and 2) whether that additional data will result in improved accuracy of genetic evaluation. This work envisions future implementation of low-coverage sequencing to reduce storage costs and enhance genetic evaluations by leveraging the additional information in the full sequence of the pangenome to account for more genetic variation. We propose addressing the storage issue by representing genomic sequence of an individual in a pair of haplotype arrays with each element pointing to an enumerated haplotype of the sequence within one of approximately 50,000 defined genome segments. Assuming 60 million genomic variants, the infrastructure required to translate the identifier of any enumerated haplotype into its genomic sequence would require less than 10 gigabytes of binary storage. Each haplotype array element would require 2 bytes, so the marginal binary storage required to represent the genomic sequence of an individual would be about 200 kilobytes (KB), similar to the genotypes from a SNP array with 200,000 markers. This assumes no pedigree and no ambiguity of the imputation, though the latter is unrealistic. Strategies to minimize, and when necessary, to manage and efficiently represent ambiguity are proposed. The genomic sequence of an individual could be stored in about 1 KB (binary) if both parents have unambiguous sequences stored as described above. The proposed system for representing the pangenome includes algorithms for read mapping and imputation intended to leverage all known genetic variation in the target population. It is also designed to use sequencing reads generated for imputing the genomic sequence of new individuals to identify unrecognized mutations, crossovers, and structural variants, thus continuously improving the genome representation, especially if widespread use of low-coverage sequencing in livestock industries is realized. This could make improved genetic merit and management of livestock feasible without computational burden.

Animals↗

PubMedDate not supplied

Kinetic characterization of acetylator genotype-dependent and -independent N-acetyltransferase isozymes in homozygous rapid and slow acetylator inbred hamster liver cytosol.

Acetyl-coenzyme A (AcCoA)-dependent arylamine N-acetyltransferase (NAT) activity (EC 2.3.1.5) was examined in liver cytosol derived from homozygous rapid acetylator (Bio. 87.20) and homozygous slow acetylator (Bio. 82.73/H) Syrian inbred hamsters. Expression of NAT activity toward p-aminobenzoic acid (PABA), 2-aminofluorene (AF), and 4-aminobiphenyl (ABP) was acetylator genotype-dependent, whereas N-acetyltransferase activity toward isoniazid was acetylator genotype-independent. Two isozymes of NAT activity were partially purified by anion exchange fast protein liquid chromatography from the hepatic cytosol of both homozygous rapid and homozygous slow acetylator hamsters. The first eluting NAT isozyme exhibited a polymorphic expression toward AF, ABP, and PABA although the second eluting NAT isozyme exhibited a monomorphic expression across acetylator genotypes toward the same substrates. Determination of Michaelis-Menten kinetic constants in hepatic cytosol of homozygous rapid and slow acetylator hamsters suggests that PABA, AF, and ABP NAT activities were acetylator genotype-dependent because of catalysis by polymorphic NAT isozyme that is both an apparent Km and Vmax variant, whereas, the acetylator genotype-independent expression of isoniazid NAT activity appeared to result from catalysis via a common monomorphic NAT isozyme in both acetylator genotypes. Additional kinetic studies on the partially purified NAT isozymes of homozygous rapid and slow acetylator hamster liver confirmed that the polymorphic NAT isozyme exhibited a substantially higher apparent maximum velocity in homozygous rapid acetylators than slow acetylators toward PABA, AF, and ABP as well as acetylator genotype-related differences in the apparent Km toward each of these substrates. In contrast, the monomorphic NAT isozyme of both acetylator genotypes showed apparent Vmax levels of NAT activity that did not vary with acetylator genotype. Furthermore, the monomorphic NAT isozyme did not show acetylator genotype-related variations in apparent Km toward the arylamine carcinogens AF and ABP, although differences were noted for PABA and AcCoA. These results suggest that the acetylator genotype-dependent expression of AcCoA-dependent NAT activity in hamster hepatic cytosol toward arylamines is primarily accountable by structural variants (allozymes) of polymorphic NAT under the genetic regulation of the acetylator gene locus. The acetylator genotype-independent expression of isoniazid NAT activity is attributable to a common monomorphic NAT isozyme in both acetylator genotypes.

4-Aminobenzoic Acid↗

PubMed1984

Structure-activity relations of LHRH in birds.

Structural requirements in LHRH for gonadotropin-releasing activity were investigated by comparing the activity of the natural vertebrate LHRH structural variants and synthetic analogues. Substitution of Arg8 results in a loss of activity of LHRH in mammals, whilst a number of amino acid substitutions for Arg8 retain high gonadotropin-releasing activity in the chicken. Thus Arg8 of LHRH comprises an integral part of the binding site of LHRH and/or contributes towards the conformation of the binding site for the mammalian receptor while this does not pertain in the bird. The possibility that relative conformational stabilization of LHRH is important for biological activity in mammals but not birds, was supported by the demonstration that a gamma-lactam conformationally constrained analogue of LHRH was more active than LHRH in the mammalian system but equipotent in the bird. The chicken LHRH receptor is also relatively undiscriminating with regard to amino acid substitutions in positions 5 and 7. A series of LHRH analogues with pure antagonist activity in rats exhibited a spectrum of activities, from pure agonist to mixed activity and pure antagonist, in the chicken. These differences in LHRH structural requirements of the mammalian and avian receptor are reflected by a difference in molecular size of the chicken receptor (67,000) and mammalian receptor (60,000). Nevertheless, like the mammalian pituitary, the chicken pituitary does exhibit "desensitization" on prolonged exposure to LHRH.

Amino Acid Sequence↗

PubMed2001

Variability of 5-HT2C receptor cys23ser polymorphism among European populations and vulnerability to affective disorder.

Substantial evidence supports a role for dysfunction of brain serotonergic (5-HT) systems in the pathogenesis of major affective disorder, both unipolar (recurrent major depression) and bipolar.(1) Modification of serotonergic neurotransmission is pivotally implicated in the mechanism of action of antidepressant drugs(2) and also in the action of mood stabilizing agents, particularly lithium carbonate.(3) Accordingly, genes that code for the multiple subtypes of serotonin receptors that have been cloned and are expressed in brain,(4) are strong candidates for a role in the genetic etiology of affective illness. We examined a structural variant of the serotonin 2C (5-HT2C) receptor gene (HTR2C) that gives rise to a cysteine to serine substitution in the N terminal extracellular domain of the receptor protein (cys23ser),(5) in 513 patients with recurrent major depression (MDD-R), 649 patients with bipolar (BP) affective disorder and 901 normal controls. The subjects were drawn from nine European countries participating in the European Collaborative Project on Affective Disorders. There was significant variation in the frequency of the HT2CR ser23 allele among the 10 population groups included in the sample (from 24.6% in Greek control subjects to 9.2% in Scots, chi(2) = 20.9, df 9, P = 0.01). Logistic regression analysis demonstrated that over and above this inter-population variability, there was a significant excess of HT2CR ser23 allele carriers in patients compared to normal controls that was demonstrable for both the MDD (chi(2) = 7.34, df 1, P = 0.006) and BP (chi(2) = 5.45, df 1, P = 0.02) patients. These findings support a possible role for genetically based structural variation in 5-HT2C receptors in the pathogenesis of major affective disorder.

Amino Acid Substitution↗

PubMed1997

Structure-activity relationships of selective estrogen receptor modulators: modifications to the 2-arylbenzothiophene core of raloxifene.

The 2-arylbenzothiophene raloxifene, 1, is a selective estrogen receptor modulator which is currently under clinical evaluation for the prevention and treatment of postmenopausal osteoporosis. A series of raloxifene analogs which contain modifications to the 2-arylbenzothiophene core have been prepared and evaluated for the ability to bind to the estrogen receptor and inhibit MCF-7 breast cancer cell proliferation in vitro. Their ability to function as tissue-selective estrogen agonists in vivo has been assayed in a short-term, ovariectomized (OVX) rat model with end points of serum cholesterol lowering, uterine weight gain, and uterine eosinophil peroxidase activity. These studies have demonstrated that (1) the 6-hydroxy and, to a lesser extent, the 4'-hydroxy substituents of raloxifene are important for receptor binding and in vitro activity, (2) small, highly electronegative 4'-substituents such as hydroxy, fluoro, and chloro are preferred both in vitro and in vivo, (3) increased steric bulk at the 4'-position leads to increased uterine stimulation in vivo, and (4) additional substitution of the 2-aryl moiety is tolerated while additional substitution at the 4-, 5-, or 7-position of the benzothiophene results in reduced biological activity. In addition, compounds in which the 2-aryl group is replaced by alkyl, cycloalkyl, and naphthyl substituents maintain a profile of in vitro and in vivo biological activity qualitatively similar to that of raloxifene. Several novel structural variants including 2-cyclohexyl, 2-naphthyl, and 6-carbomethoxy analogs also demonstrated efficacy in preventing bone loss in a chronic OVX rat model of postmenopausal osteopenia, at doses of 0.1-10 mg/kg.

Adenocarcinoma↗

PubMed1993

RP-HPLC peptide mapping methods for the analysis of recombinant human pro-urokinase.

Among the techniques available for the detection of protein structure variants such as single point mutations, RP-HPLC peptide mapping plays a key role owing to the high reproducibility of peptide retention times, determined as identity indexes. Because of the possible co-elution of some proteolytic fragments, an improvement of the array of information given by the technique can be achieved by setting up a series of experiments under hydrolytic conditions with different enzymes, followed by appropriate RP-HPLC gradient elutions. Such an experimental approach appears to be particularly useful in the examination of proteins with a high molecular weight, where the resulting RP-HPLC maps are complex. Therefore different RP-HPLC peptide mapping methods have been studied for recombinant human pro-urokinase (r-h-proUK), a thrombolytic agent of apparent molecular weight of 46 kD. The RP-HPLC maps indicate that the methods developed are not only suitable for the qualitative control of the amino acid sequence and arrangement of disulphide bonds but also represent the first demonstration of the identity of the primary structure of the recombinant and of the native species, within the limits of the technique.

Amino Acid Sequence↗

PubMed1987

The sorangicins, novel and powerful inhibitors of eubacterial RNA polymerase isolated from myxobacteria.

A new antibiotic, sorangicin, was isolated from the culture supernatant of the myxobacterium, Sorangium (Polyangium) cellulosum strain So cel2. It is a macrocyclic lactone carbonic acid and is produced in two structural variants, sorangicins A and B. In addition small quantities of the respective glycosides, sorangiosids A and B, may be found. The antibiotic acts mainly against Gram-positive bacteria, including myocobacteria, with MIC values between 0.01 and 0.1 microgram/ml, but at higher concentrations (MIC 3 approximately 30 micrograms/ml) Gram-negatives are also inhibited. Yeasts and molds are completely resistant. The new antibiotic is a specific inhibitor of eubacterial RNA polymerase which it blocks, however, only if added before RNA polymerization has started.

Aminoglycosides↗