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11.
S Amati E Petrini G Gazzanelli F Osculati M Caucci 《Bollettino della Società italiana di biologia sperimentale》1979,55(4):378-382
In the present study some aspects of Sertoli cells of testicular-biopsy specimens of children from 0 to 8 years old are examined. We can distinguish two main morphological situations. In the first one, Sertoli cells with monomorphic aspect can be seen; in the second can be shown Sertoli cells with various aspects. In this polimorphic situation we can distinguish three Sertoli cell types differing in cellular shape, cytoplasme electron-density and amount of RER and Golgi complex. 相似文献
12.
Giancarlo Lunazzi Claudio Tiribelli Bruno Gazzin Gianluigi Sottocasa 《生物化学与生物物理学报:生物膜》1982,685(2):117-122
Bilitranslocase, a plasma membrane protein involved in bilirubin and other organic anion uptake by the liver, exhibits a high molecular weight (170 000) when isolated in the presence of deoxycholate. This value is decreased to approx. 100 000 if deoxycholate is not included in the isolation medium. Both preparations can be resolved into two kinds of subunit, α and β, of 37 000 and 35 500, respectively, by reduction with 2-mercaptoethanol and addition of sodium dodecyl sulfate. Under these conditions the two subunits are still capable of high-affinity sulfobromophthalein binding and, despite the presence of the detergent, may be isolated by preparative polyacrylamide gel electrophoresis still associated with the dye. It may be suggested that the physiological subunit composition of bilitranslocase is α2-β. 相似文献
13.
M Magnani G Serafini A Antonelli M Malatesta G Gazzanelli 《The Journal of biological chemistry》1991,266(31):21018-21024
Conjugate ubiquitin was previously found in the nucleus, cytoplasm, and membranes of eukaryotic cells while the enzymes of the ubiquitin-conjugating system appear to be cytoplasmic. We have prepared the mitochondrial fraction from rabbit brain by discontinuous density gradient ultracentrifugation and by Western blotting, using a specific antibody against conjugate ubiquitin, showing that it contains ubiquitin conjugates in a very wide molecular weight range. Electron microscopy and measurement of specific enzyme markers show that this fraction not only contains mitochondria but also some endoplasmic reticulum vesicles. Immunostaining with anti-ubiquitin IgG followed by immunodecoration with colloidal gold particles provides evidence for the presence of conjugate ubiquitin both in mitochondria and in the endoplasmic reticulum. Furthermore, this "mitochondrial fraction" shows a pronounced ATP-dependent ability to conjugate 125I-ubiquitin into a number of endogenous proteins as evidenced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. Addition of E1, E2, and E3, the enzymes of the ubiquitin conjugating system purified from rabbit reticulocytes, does not further increase this ubiquitination nor incorporate 125I-ubiquitin into additional protein bands. The same mitochondrial fraction is not able to carry out any ATP-dependent degradation of 125I-albumin; however, it contains an isopeptidase activity able to release the covalently incorporated 125I-ubiquitin and is also able to conjugate 125I-ubiquitin to exogenous proteins as oxidized RNase. By affinity chromatography on ubiquitin-agarose of fraction II of a crude Triton X-100 extract of the mitochondrial fraction, several proteins corresponding in Mr to the E1 and E2s enzymes were obtained. These proteins were also able to form specific ubiquitin-thiol ester bounds on sodium dodecyl sulfate-polyacrylamide gels and to support 125I-ubiquitin conjugation to oxidized RNase. Detergent fractionation of the mitochondrial fraction provided evidence for a possible localization of the ubiquitin conjugating activity in the mitochondrial external membrane and endoplasmic reticulum. The presence of an active ubiquitin protein conjugating system in mitochondria and endoplasmic reticulum may be related to the turnover of organelle proteins as well as to specific cell functions such as import of proteins into mitochondria and ubiquitination of externally oriented membrane-bound proteins. 相似文献
14.
Arnold Demain Giancarlo Lancini 《Journal of industrial microbiology & biotechnology》1991,7(2):155-156
Society for Industrial Microbiology 相似文献
15.
Bruno Samorì Giorgio Lenaz Maurizio Battino Giancarlo Marconi Ida Domini 《The Journal of membrane biology》1992,128(3):193-203
Summary A general approach is developed to interpret linear dichroism (LD) spectra of ubiquinones (Q
n) in host bilayers. Information is reported in terms of guest-host mutual orientation and localization. The overall orientational anisotropy of guest ubiquinone molecules is described by a basic set of limiting orientation/localization modes. Assignments of the UV transitions of the ubiquinone chromophore were obtained by the liquid crystal-linear dichroism technique and molecular orbital (CNDO/S) calculations. The LD spectra of Q
n in the bilayers provided by the lyotropic nematic mesophase exhibited by water solutions of potassium laurate and decanol were interpreted on the basis of the above assignments. The resulting experimental evidence showed a multisite distribution in the host bilayer for the aromatic heads of all the investigated Q
n derivatives except Q0. The orientational distribution suggested by the LD spectra fits the solubilization model recently proposed by G. Lenaz [J. Membrane Biol. (1988) 104:193–209] for ubiquinone in lipid membranes. Within this model Q
n molecules are located in the midplane and their headgroups oscillate transversally across the membrane. Q
0 instead has a single site location, close to the polar bilayer interface. Experimental evidence that the headgroup carbonyls tend to grasp the polar interface of the host bilayer was also obtained. Orientation and location distributions of Q
n guest molecules are therefore likely to result from the tendency of their aromatic heads to grasp the polar heads of the host bilayer and from the concurrent tendency of their chains to settle into the hydrocarbon host interior.abbreviations AA
average absorption
- OD, OD
optical densities for plane polarized radiations parallel () and perpendicular () to the sample optical axis
- OD
OD — OD
- EPR
electron paramagnetic resonance
- LC-LD
liquid crystal-linear dichroism
- LD
linear dichroism
-
LD
r
reduced linear dichroism.
- MO
molecular orbital
- N
nematic
- NMR
nuclear magnetic resonance
-
S
jj
order parameters of the directions j of the transition moments of the guest chromophore
-
S
ii
order parameters of the orientational axes i of the guest molecule with respect to the magnetic field
-
S
ii
order parameters of the axes i of the guest molecules with respect to the bilayer axis a
-
S
a
order parameters of the host bilayer axis a with respect to the orienting magnetic field
-
j,i
deflection angles between the directions j and the axes i
-
O
i
optical factors of the i axis see Eq. (A4)]
- Qn
ubiquinone whose isoprenoid chain contains n isoprenoid units
Dr. A. Rossi is gratefully acknowledged for the t.e.m. reduction of the spectra. Ubiquinone homologs were kind gifts from Eisai Co., Tokyo, Japan. This work was supported by M.U.R.S.T., and C.N.R. Target Project on Biotechnology and Bioinstrumentation, Rome, Italy. 相似文献
16.
Giuseppe Bellucci Giancarlo Berti Maria Ferretti Franco Marioni Franca Re 《Biochemical and biophysical research communications》1981,102(3):838-844
The hydrolysis of (±)--3-bromo-1,2-epoxycyclohexane in the presence of rabbit liver microsomes was investigated, and found to yield, beside -3-bromocyclohexane--1,-2-diol, 2,3-epoxycyclohexanol. It was demonstrated that the latter compound was the only product of the enzymatic reaction, whereas the diol resulted from a non enzymatic hydration in the reaction medium. These data provide the first direct proof for a general base catalysis in the enzymatic epoxide hydration, previously hypothesized on the basis of several lines of indirect evidence, and disprove alternative mechanisms involving protonation of the oxirane oxygen. 相似文献
17.
18.
19.
Robert P. Wagensommer Giancarlo Bistocchi Andrea Arcangeli Andrea Rubini Claudia Perini Roberto Venanzoni 《Plant biosystems》2013,147(6):1329-1337
AbstractA Red List of all 108 Pezizomycotina (Ascomycota) species recorded in Umbria Region (central Italy) is provided. According to the IUCN categories and criteria, 60.18% of the assessed species are classified as threatened, whereas 12.96% are Near Threatened (NT), 1.86% are Least Concerned (LC) and a noteworthy amount of 25% are Data Deficient (DD). As a consequence of the downlisting applied to the majority of the assessed taxa, according to the guidelines for application of IUCN red list criteria at Regional level, only 1.54% of the threatened species is Critically Endangered (CR), while 46.15% are Endangered (EN) and 52.31% are Vulnerable (VU). Given that the present work represents the first complete regional red list of Pezizomycotina in Italy, and that a national, as well as a European red list do not exist to date, it could be considered as a case study for other Italian Regions as well as for other European countries, aiming at the compilation of a national and European red list of this fungal group mostly overlooked in conservation strategies. 相似文献
20.
Francesco Migliavacca Giancarlo Pennati Elena Di Martino Gabriele Dubini Riccardo Pietrabissa 《Computer methods in biomechanics and biomedical engineering》2013,16(3):243-248
The modified Blalock-Taussig shunt is a surgical procedure used as a palliation to treat complex congenital heart defects. It consists of an interposing prosthetic tube between the innominate/subclavian artery and the right pulmonary artery. Previous experience indicates that the pressure drop across the shunt is affected by the pulmonary pressure at the distal anastomosis combined with the distensibility of the anastomosis. In this study, a computational fluid-structure interaction approach is presented to investigate the haemodynamic behaviour. Steady-state fluid dynamics and structural analyses were carried out using commercial codes based on the finite element method (FIDAP and ABAQUS) coupled by means of a purposely-developed procedure to transfer boundary conditions. Both prosthetic tube and artery walls were characterised by non-linear material properties. Three different pulmonary pressures (2, 5 and 15 mmHg) and two volume flow rates (0.4 and 0.8 l/min) were investigated. Results indicate that the effects of distensibility at the distal anastomosis on the shunt pressure drop are relevant only when the distal anastomosis on the shunt pressure drop are relevant only when the distal anastomosis is not fully distended, which occurs when the pulmonary pressure is lower than 5 mmHg. 相似文献