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11.
S. Aime Mauro Botta S. Geninatti Crich Giovanni B. Giovenzana Roberto Pagliarin Maurizio Piccinini Massimo Sisti Enzo Terreno 《Journal of biological inorganic chemistry》1997,2(4):470-479
A novel heptacoordinating ligand consisting of a thirteen-membered tetraazamacrocycle containing the pyridine ring and bearing
three methylenephosphonate groups (PCTP-[13]) has been synthesized. Its Gd(III) complex displays a remarkably high longitudinal
water proton relaxivity (7.7 mM–1 s–1 at 25 °C, 20 MHz and pH 7.5) which has been accounted for in terms of contributions arising from (1) one water molecule
bound to the metal ion, (2) hydrogen-bonded water molecules in the second coordination sphere, or (3) water molecules diffusing
near the paramagnetic chelate. Variable-temperature 17O-NMR transverse relaxation data indicate that the residence lifetime of the metal-bound water molecule is very short (8.0 ns
at 25 °C) with respect to the Gd(III) complexes currently considered as contrast agents for magnetic resonance imaging. Furthermore,
GdPCTP-[13] interacts with human serum albumin (HSA), likely through electrostatic forces. By comparing water proton relaxivity
data for the GdPCTP-[13]-HSA adduct, measured as a function of temperature and magnetic field strength, with those for the
analogous adduct with GdDOTP (a twelve-membered tetraaza macrocyclic tetramethylenephosphonate complex lacking a metal-bound
water molecule), it has been possible to propose a general picture accounting for the main determinants of the relaxation
enhancement observed when a paramagnetic Gd(III) complex is bound to HSA. Basically, the relaxation enhancement in these systems
arises from (1) water molecules in the hydration shell of the macromolecule and protein exchangeable protons which lie close
to the interaction site of the paramagnetic complex and (2) the metal bound water molecule(s). As far as the latter contribution
is concerned, the interaction with the protein causes an elongation of the residence lifetime of the metal-bound water molecule,
which limits, to some extent, the potential relaxivity enhancement expected upon the binding of the paramagnetic complex to
HSA.
Received: 27 January 1997 / Accepted: 12 May 1997 相似文献
12.
From ligulate flowers of Matricaria chamomilla was isolated a mixture of apigenin 7-O-β-glucoside diacetates, which was shown to be based on (2″, 3″)- and (3″, 4″)-diacetates. 相似文献
13.
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
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Syatkin Sergey P. Neborak Ekaterina V. Khlebnikov Andrei I. Komarova Marina V. Shevkun Natalia A. Kravtsov Eduard G. Blagonravov Mikhail L. Agostinelli Enzo 《Amino acids》2020,52(2):199-211
Amino Acids - The polyamine (PA) metabolism is involved in cell proliferation and differentiation. Increased cellular PA levels are observed in different types of cancers. Products of PA oxidation... 相似文献
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17.
Alice Accorsi Laura Bucci Magda de Eguileor Enzo Ottaviani Davide Malagoli 《Fish & shellfish immunology》2013,34(5):1260-1268
Molluscs are invertebrates of great relevance for economy, environment and public health. The numerous studies on molluscan immunity and physiology registered an impressive variability of circulating hemocytes. This study is focused on the first characterization of the circulating hemocytes of the freshwater gastropod Pomacea canaliculata, a model for several eco-toxicological and parasitological researches.Flow cytometry analysis identified two populations of hemocytes on the basis of differences in size and internal organization. The first population contains small and agranular cells. The second one displays major size and a more articulated internal organization. Light microscopy evidenced two principal morphologies, categorized as Group I (small) and II (large) hemocytes. Group I hemocytes present the characteristics of blast-like cells, with an agranular and basophilic cytoplasm. Group I hemocytes can adhere onto a glass surface but seem unable to phagocytize heat-inactivated Escherichia coli. The majority of Group II hemocytes displays an agranular cytoplasm, while a minority presents numerous granules. Agranular cytoplasm may be basophilic or acidophilic. Granules are positive to neutral red staining and therefore acidic. Independently from their morphology, Group II hemocytes are able to adhere and to engulf heat-inactivated E. coli. Transmission electron microscopy analysis clearly distinguished between agranular and granular hemocytes and highlighted the electron dense content of the granules. After hemolymph collection, time-course analysis indicated that the Group II hemocytes are subjected to an evident dynamism with changes in the percentage of agranular and granular hemocytes. The ability of circulating hemocytes to quickly modify their morphology and stainability suggests that P. canaliculata is endowed with highly dynamic hemocyte populations able to cope with rapid environmental changes as well as fast growing pathogens. 相似文献
18.
Elena De Falco Gaia Scafetta Chiara Napoletano Rosa Puca Enzo Maria Vingolo Giuseppe Ragona Olga Iorio Giacomo Frati 《Cell and tissue banking》2013,14(2):277-287
Good manufacturing practices guidelines require safer and standardized cell substrates especially for those cell therapy products to treat ocular diseases where fibroblasts are used as feeder layers. However, if these are unavailable for stem cells culturing, murine fibroblasts are regularly used, raising critical issues as accidentally transplanting xenogenous graft and adversely affecting stem cell clinical trials. Moreover, human fibroblasts play a significant role in testing novel ophthalmologic drugs. Accordingly, we developed a standardized laboratory and surgical approach to isolate normal and undamaged Tenon’s fibroblasts to implement the setting up of banks for both stem cells-based ocular cell therapy and in vitro drug testing. A 2–3 cm2 undamaged Tenon’s biopsy was surgically obtained from 28 patients without mutually correlated ocular diseases. Nineteen dermal biopsies were used as control. Fibroblasts were isolated with or without collagenase, cultured in autologous, fetal bovine or AB serum, tested for viability by trypan blue, vimentin expression and standardized until passage 6. Successful Tenon’s fibroblasts isolation was age dependent (P = 0.001) but not sex, pathology or surgery related. A significant rate of successful cultures were obtained when biopsies were not digested by collagenase (P = 0.013). Moreover, cultures in autologous or fetal bovine serum had comparable proliferative properties (P = 0.77; P = 0.82). Through our surgical and laboratory standardized procedure, we elucidated for the first time key points of this human primary culture system, the role of the autologous serum, comparing Tenon’s and dermal fibroblasts. Our protocol may be clinically useful to reduce the risk above mentioned and may be potentially more effective for ophthalmological clinical purposes. 相似文献
19.
Uedson Pereira Jacobina Marcelo Ricardo Vicari Pablo Ariel Martinez Marcelo de Bello Cioffi Luiz Antonio Carlos Bertollo Wagner Franco Molina 《Helgoland Marine Research》2013,67(3):499-506
Fish of the genus Selene, known as lookdowns or moonfish, are one of the most morphologically derived groups of the family Carangidae, whose phylogenetic relationships are still largely unknown. In this study, we discuss karyoevolutionary aspects of three representatives of this genus from the Western Atlantic: Selene brownii (2n = 48; FN = 48), Selene setapinnis (2n = 46; FN = 48), and Selene vomer (2n = 48; FN = 50). Their body patterns were also investigated and compared to one another and in relation to two other species of different genera. Two mechanisms of karyotypic evolution seem to have acted in the diversification of this genus, namely pericentric inversions and centric fusions. Mapping of rDNA sequences showed that chromosome pairs bearing 5S rDNA sites are similar, whereas those bearing 18 rDNA sites are morphologically distinct while apparently also exhibiting interspecies synteny. Although the nucleolar organizer-bearing chromosomes are extremely efficient cytotaxonomic markers among Selene species, others cytogenetic patterns of these species are relatively conserved. Hybridization with telomeric probes (TTAGGG)n did not exhibit interstitial telomeric sites (ITS), especially in S. setapinnis, where, along with a reduction in diploid number, a large metacentric pair derived from centric fusion is present. Data obtained by geometric morphometrics enable a clear morphological distinction among the three species, as well as in relation to two other species of the genus Caranx and Oligoplites. Data obtained suggest that morphologic evolution in Selene species was primarily dissociated from visible changes that occurred at the chromosomal level. 相似文献
20.
Aleksandar Zocevic Fabien Vorimore Nadia Vicari Julien Gasparini Lisa Jacquin Konrad Sachse Simone Magnino Karine Laroucau 《PloS one》2013,8(3)
Recent evidence of the occurrence of atypical Chlamydiaceae strains in pigeons, different from the established Chlamydiaceae, requires the development of a specific and rapid detection tool to investigate their prevalence and significance. Here is described a new real-time PCR assay that allows specific detection of atypical Chlamydiaceae from pigeons. The assay has been used to assess the dissemination of these strains in field samples collected from Parisian pigeon populations in 2009. The results suggest a limited dissemination compared to the usually higher prevalence of Chlamydia psittaci that is the main species associated with avian chlamydiosis. 相似文献