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1.
Bianca Colonna Maria Bernardini Gioacchino Micheli Francesco Maimone Mauro Nicoletti Mariassunta Casalino 《Plasmid》1988,20(3):221-231
Tn1935, a 23.5-kb transposon mediating resistance to ampicillin, kanamycin, mercury, spectinomycin, and sulfonamide was isolated from pZM3, an IncFIme virulence plasmid from Salmonella wien. Tn1935 possesses the entire sequence of Tn21 and contains two additional DNA segments of 0.95 and 2.7 kb carrying the ampicillin and kanamycin resistance genes, respectively. The latter is part of a composite element since it is flanked by two IS15-like insertion sequences (IS1936) in direct orientation. IS1936 is about 800 bp long and is closely related to IS15 delta, IS26, IS46, IS140, and IS176. Functional analysis of IS1936-mediated cointegrates shows that both insertion sequences are active and able to form cointegrates at the same frequency. Resolution of the cointegrates requires the presence of the host Rec system. The presence of the composite IS1936-element within Tn1935 supports the hypothesis that multidrug resistance transposons evolved by insertion of antibiotic determinants which are themselves transposable. 相似文献
2.
Curtis C. Maier Bianca Marchetti Robert D. LeBoeuf J. Edwin Blalock 《Cellular and molecular neurobiology》1992,12(5):447-454
1. A luteinizing hormone-releasing hormone (LHRH)-like molecule produced by thymocytes is similar to hypothalamic LHRH in both bioactivity and antigenicity. 2. We determined whether this thymic LHRH is identical to or only homologous with hypothalamic LHRH by synthesizing and sequencing the cDNA of rat thymus LHRH. 3. The thymocyte and hypothalamic LHRH cDNAs are identical, indicating, that the amino acid sequences of LHRH produced in the hypothalamus and the immune system are also identical. 4. This is the first report showing conclusively that cell of the immune system transcribe the authentic mRNA for a hypothalamic releasing factor, LHRH. 相似文献
3.
Cyclic AMP inhibition of phosphoinositide turnover in human neutrophils 总被引:10,自引:0,他引:10
V Della Bianca P De Togni M Grzeskowiak L M Vicentini F Di Virgilio 《Biochimica et biophysica acta》1986,886(3):441-447
The effect of increased intracellular levels of cyclic AMP on phosphoinositide metabolism was studied in human neutrophils stimulated with fMet-Leu-Phe. Intracellular cyclic AMP was raised by preincubation either with dibutyryl cyclic AMP and theophylline or with prostaglandin E1. Concentrations of dibutyryl cyclic AMP and theophylline fully inhibitory for the metabolic responses inhibited phosphoinositide breakdown and phosphatidic acid formation to a large extent. The accumulation of the water-soluble inositol phosphates was also measured. In agreement with the data obtained on the phospholipids, inositol phosphate generation was found to be severely, though not completely, reduced. Treatment with dibutyryl cyclic AMP and theophylline also inhibited resynthesis of membrane inositol lipids. Treatment with prostaglandin E1 had a similar, though less, marked effect on inositol lipid turnover, which was parallel with a smaller inhibition of metabolic responses. We therefore suggest that the elevation of intracellular cyclic AMP mainly affects neutrophil responses by inhibiting the phosphoinositide cycle. 相似文献
4.
V Della Bianca M Grzeskowiak P De Togni M Cassatella F Rossi 《Biochimica et biophysica acta》1985,845(2):223-236
Verapamil inhibits in human neutrophils the respiratory burst, the secretion and the change of transmembrane potential induced by formylmethionylleucylphenylalanine, a Ca2+-dependent stimulus, and by phorbol myristate acetate, a Ca2+-independent stimulus. Besides the blocking of Ca2+ channels, many mechanisms are responsible for the inhibition of neutrophil responses. In fact, verapamil (i) increases the intracellular cAMP concentration, potentiates the cAMP response induced by the chemotactic peptide and induces the appearance of a cAMP response also when the stimulant is phorbol myristate acetate; (ii) causes a decrease of Ca2+ association to cell membranes, so depleting the pools of exchangeable Ca2+ and depressing the 'Ca2+ response' in terms of rise in [Ca2+]i monitored with Quin 2 and of rapid mobilization from cell membranes monitored by chlorotetracycline fluorescence change; (iii) inhibits the Ca2+-activated phospholipid-dependent protein kinase C. The data, discussed in relation to the biochemical mechanisms of the stimulus-response coupling, are compatible with the hypothesis of an involvement of the activation of protein kinase C as key step in the sequence of transduction events for the induction of many neutrophil functions. 相似文献
5.
P De Togni V Della Bianca P Bellavite M Grzeskowiak F Rossi 《Biochimica et biophysica acta》1983,755(3):506-513
Studies were carried out on the mechanism responsible for the enhancement of the respiratory and secretory responses to N-formylmethionylleucylphenylalanine (fMet-Leu-Phe) exhibited by human neutrophils suspended in Na+-free, high-K+ buffered solution. The results demonstrate that: (a) the variation of Na+ concentration in the suspending solution induces in human neutrophils a marked modification of the recognition apparatus for the chemotactic peptide fMet-Leu-Phe, the lack of or low concentration of this ion increasing the number of the receptors and their specific affinity for the ligand; (b) the greater respiratory burst and secretion induced by fMet-Leu-Phe in human neutrophils suspended in Na+-free, high-K+ medium are due to the increased formation of receptor-ligand complexes at the cell membrane; (c) the greater respiratory response is partially due also to a higher efficiency of these receptor-ligand complexes. The molecular mechanism by which Na+ exerts a regulative role on the properties of the recognition apparatus for the chemotactic peptide and its possible significance are discussed. 相似文献
6.
W. Bianca 《International journal of biometeorology》1968,12(2):153-157
In cattle the water content of the skin was determined (1) in the normal animals; (2) after a 3-day period of water deprivation (dehydration); (3) one hour after the water deprived animals had resumed drinking (rehydration)and (4) one hour after the beginning of infusion of water into the rumen of normal animals (overhydration). Dehydration reduced the water content of the skin from 70.6 to 65.8% on average. Rehydration led to a partial restoration of the water content of the skin. Overhydration did not have a measurable effect on the water content of the skin. A rough estimation of the total amount of water lost during dehydration from the total skin of each animal indicated that on average the calves lost 315 ml,the oxen 1,336 ml of water from their skins.
Zusammenfassung Beim Rind wurde der Wassergehalt der Haut bestimmt (1)in normalem Zustand der Tiere; (2) nach einer dreitägigen Wasserenthaltung der Tiere (Dehydration); (3) eine Stunde nachdem die dehydrierten Tiere wieder zu trinken begannen(Rehydration) und (4) eine Stunde nach begonnener Infusion von Wasser in den Pansen von normalen Tieren (Überhydration). Dehydration verursachte einen mittleren Abfall des Wassergehaltes der Haut von 70.6 auf 65.8%. Rehydration führte zu einer teilweisen Wiederherstellung des normalen Wassergehaltes der Haut, während Überhydration ohne messbaren Einfluss blieb. Der berechnete Wasserverlust von der gesamten Haut als Folge der Dehydration war 315 ml bei den Kälbern und 1.336 ml bei den Ochsen.
Resume On a déterminé la teneur en eau de la peau des bovidés sous quatre conditions: (1) chez des bêtes à l'état normal; (2) par déshydratation (après 3 jours sans abreuvage); (3) une heure après que les bêtes déshydratées aient reçu à boire (réhydratation); (4) une heure après le début d'une infusion d'eau dans la panse de bêtes à l'état normal (surhydratation). L'état de déshydratation a provoqué une baisse moyenne du taux de l'eau cutanée de 70,6% à 65,8%. La réhydratation a eu pour conséquence la reconstitution partielle de la teneur en eau de la peau alors que la surhydratation ne semble pas avoir eu d'effets. La perte en eau calculée par suite de déshydratation fut de 315 ml pour les veaux, de 1,336 ml pour les boeufs.相似文献
7.
Socrates J. Tzartos Heleni V. Loutrari Fen Tang Anna Kokla Susan L. Walgrave Robert P. Milius† Bianca M. Conti-Tronconi 《Journal of neurochemistry》1990,54(1):51-61
Most anti-nicotinic acetylcholine receptor (AChR) antibodies in myasthenia gravis are directed against an immunodominant epitope or epitopes [main immunogenic region (MIR)] on the AChR alpha-subunit. Thirty-two synthetic peptides, corresponding to the complete Torpedo alpha-subunit sequence and to a segment of human muscle alpha-subunit, were used to map the epitopes for 11 monoclonal antibodies (mAbs) directed against the Torpedo and/or the human MIR and for a panel of anti-AChR mAbs directed against epitopes on the alpha-subunit other than the MIR. A main constituent loop of the MIR was localized within residues alpha 67-76. Residues 70 and 75, which are different in the Torpedo and human alpha-subunits, seem to be crucial in determining the binding profile for several mAbs whose binding to the peptides correlated very well with their binding pattern to native Torpedo and human AChRs. This strongly supports the identification of the peptide loop alpha 67-76 as the actual location of the MIR on the intact AChR molecule. Residues 75 and 76 were necessary for binding of some mAbs and irrelevant for others, in agreement with earlier suggestions that the MIR comprises overlapping epitopes. Structural predictions for the sequence segment alpha 67-76 indicate that this segment has a relatively high segmental mobility and a very strong turning potential centered around residues 68-71. The most stable structure predicted for this segment, in both the Torpedo and human alpha-subunits, is a hairpin loop, whose apex is a type I beta-turn and whose arms are beta-strands. This loop is highly hydrophilic, and its apex is negatively charged. All these structural properties have been proposed as characteristic of antibody binding sites. We also localized the epitopes for mAbs against non-MIR regions. Among these, the epitope for a monoclonal antibody (mAb 13) that noncompetitively inhibits channel function was localized within residues alpha 331-351. 相似文献
8.
Characterization of a Small Family (CAIII) of Microsatellite-Containing Sequences with X-Y Homology 总被引:4,自引:0,他引:4
Patrizia Malaspina Bianca Maria Ciminelli Luigi Viggiano Carla Jodice Fulvio Cruciani Piero Santolamazza Daniele Sellitto Rosaria Scozzari Luciano Terrenato Mariano Rocchi Andrea Novelletto 《Journal of molecular evolution》1997,44(6):652-659
Four X-linked loci showing homology with a previously described Y-linked polymorphic locus (DYS413) were identified and characterized.
By fluorescent in situ hybridization (FISH), somatic cell hybrids, and YAC screening, the X-linked members of this small family
of sequences (CAIII) all map in Xp22, while the Y members map in Yq11. These loci contribute to the overall similarity of
the two genomic regions. All of the CAIII loci contain an internal microsatellite of the (CA)n type. The microsatellites display extensive length polymorphism in two of the X-linked members as well as in the Y members.
In addition, common sequence variants are found in the portions flanking the microsatellites in two of the X-linked members.
Our results indicate that, during the evolution of this family, length variation on the Y chromosome was accumulated at a
rate not slower than that on the X chromosome. Finally, these sequences represent a model system with which to analyze human
populations for similar X- and Y-linked polymorphisms.
Received: 29 July 1996 / Accepted: 15 January 1997 相似文献
9.
Concetta Compagno Aldo Tura Bianca Maria Ranzi Enzo Martegani 《Applied microbiology and biotechnology》1992,36(4):535-537
Summary One of the methods commonly used for manufacturing fructose 1,6-diphosphate is based on the enzymatic phosphorylation of glucose with inorganic phosphate using permeabilized brewer's yeast cells. Our results demonstrate that a substantial improvement in the yield of bioconversion can be achieved using fed-batch-grown Saccharomyces cerevisiae cells. Under an appropriate glucose and phosphate to cell ratio the efficiency of bioconversion reaches 70% of the theoretical value.
Offprint requests to: C. Compagno 相似文献
10.