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991.
Letizia Mattii Francesco Bianchi Iana Da Prato Amelio Dolfi Nunzia Bernardini 《In vitro cellular & developmental biology. Animal》2001,37(4):251-258
Summary The present study was performed in four renal cell lines to evaluate their capability to: (1) produce and express transforming
growth factor α (TGFα), its respective receptor, the epidermal growth factor receptor (EGFr) and the small G protein, RhoA,
and (2) exhibit morphogenetic properties when grown on Matri-cell substrates. The cell lines were derived from normal (Madin-Darby
canine kidney cells), embryonic (SK-NEP-1 and 293 cells), and cancerous (human renal adenocarcinoma cells) kidneys. TGFα messenger
ribonucleic acid evaluated by a nonradioactive in situ hybridization technique, was found to be expressed in all the cell
lines. Large amounts of TGFα peptide were observed in all four cell lines, while EGFr was highly expressed only in cancerous
ACHN and embryonic-tumor SK-NEP-1 cells. RhoA peptide was found in appreciable amounts in SK-NEP-1 and 293 cells (compared
to the other two cell lines). The morphogenetic properties of the four cell lines were assessed, by culturing them on Matri-cell
dishes: SK-NEP-1 cells alone were found to grow in three-dimensional structures forming clusters and worm-like cellular aggregates.
This feature was displayed by SK-NEP-1 cells but not by the other three cell lines, and may be connected with the contemporary
presence of RhoA, EGFr, and TGFα found in significant amounts only in the SK-NEP-1 cell line. 相似文献
992.
Nenad Bukvic Mattia Gentile Francesco Susca Margherita Fanelli Gabriella Serio Lucia Buonadonna Antonio Capurso Ginevra Guanti 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2001,498(1-2)
In the present study we analysed the possible effect of age, sex and smoking on the mean values of micronucleus (MN) and sister chromatid exchange (SCE) frequencies on peripheral blood obtained from 38 subjects ranging in age from 16 to 63 years and 16 centenarians. The mean number of binucleated cells with micronuclei varied in function of age and sex (as demonstrated by the analysis of covariance (F=13.13; P<0.001), particularly evident was the increment observed in women with increasing age (interaction age/sex: F=5.53; P<0.05). Smoking habits had no effects on MN frequency (F=0.36; P>0.05). Sex (F=4.18; P<0.05) and smoking habits (F=14.64; P<0.001) influenced significantly SCE per cell frequencies, but age had no effects on them (F=2.45; P>0.05).The age-associated increase of sex chromosome loss was studied using fluorescence in situ hybridisation (FISH) on interphase nuclei.The loss of Y signals was observed in 10% of interphase cells from the centenarians males, that is six times more often than in the younger control men (1.6%). The frequency of X signal loss (1.7%) in young women was similar to that observed in male controls of the same age but the incidence of the X chromosome aneuploidy in centenarian females was appreciably higher (22%) than that found for the Y chromosome in males. These results were correlated with the data on MN formation and a positive correlation between the percentage of aneuploid cells (FISH) and MN values was observed (r=0.50; P<0.05). 相似文献
993.
Maria Cantarella Francesco Alfani Laura Cantarella Alberto Gallifuoco Alida Saporosi 《Journal of Molecular Catalysis .B, Enzymatic》2001,11(4-6):867-875
The enzymatic hydrolysis of wheat straw was carried out in bi-phasic media prepared with acetate esters and Na-acetate buffer. The volume percentage of the organic chemicals was 75%. The biomass was pretreated in a steam explosion plant at 217°C and for 3 min. A cellulase complex from commercial source was utilised and the experiments were run at 45°C and at constant enzyme to biomass weight ratio (0.06). Biomass loadings ranged from 6.25 to 100 g per litre of reactor. The amount of glucose formed per litre of reactor and hour and the glucose yield (grams of product per gram of biomass) were close to the values attained in pure buffer. The glucose concentration in the aqueous phase was in bi-phasic media much higher than in pure buffer and reached the value of 146 g lH2O−1 during 72 h of saccharification. The results were poorly dependent on the physical–chemical properties of the solvents. Nevertheless, butyl acetate could be slightly preferred to propyl and i-amyl acetate. The use of bi-phasic media did not require stirring rate higher than in pure buffer. The presence of acetate ester traces did not alter markedly the production of ethanol in the fermentation stage, but determined the extension of the lag phase. 相似文献
994.
Aberrant spermatogenesis and sex determination in Bourletiellidae (Hexapoda, Collembola), and their evolutionary significance 总被引:1,自引:0,他引:1
R. Dallai Pietro Paolo Fanciulli Antonio Carapelli Francesco Frati 《Zoomorphology》2001,120(4):237-245
Light and electron microscopic evidence is provided to describe a new example of a postzygotic sex-determination system in
two collembolan species, Bourletiella arvalis and B. hortensis. In B. arvalis, where chromosome number could be assessed, both sexes are homogametic (n=6) and all zygotes have an identical chromosome
composition (2n=12). However, male embryos develop after the loss of two sex chromosomes, making the male genotype 2n=10 (4AAX10X20). On the other hand, female embryos develop if the zygote retains all chromosomes and the female genetic system is, therefore,
4AAX1X1X2X2 (2n=12). As an apparent consequence of the lack of two chromosomes in the male germ cells, spermatogenesis is aberrant. At
the first meiotic division, in fact, the two resulting secondary spermatocytes receive a different number of chromosomes:
six and four. The cells which receive six chromosomes (one haploid set of four autosomes and two sex chromosomes) proceed
through the meiotic process and the two spermatids generated produce two spermatozoa by a normal spermiogenesis. The cells
receiving only four chromosomes do not undergo the second meiotic division and soon degenerate. The degenerating cells can
be considered a morphological marker for this process, as they are easily recognizable at the electron microscope from the
functional secondary spermatocytes by the appearance of the nucleus (totally condensed), the reduction of the cytoplasm (limited
to a thin layer surrounding the nucleus), and the lack of most cytoplasmic organelles (with the exception of a couple of centrioles).
Electron microscopic evidence has been collected for both species, allowing to extend the same process to B. hortensis, even if chromosomes could not be counted in this species. Therefore, as a result of the spermatocyte elimination, the efficiency
of spermatogenesis is reduced to 50%. This process is identical to that observed in other collembolan species of the suborder
Symphypleona, and it is suggested that it represents a synapomorphic feature uniting the families Dicyrtomidae, Sminthuridae
and Bourletiellidae (Sminthuriformia). It is also suggested that the process is related with the finding of a distorted sex
ratio in natural populations and, possibly, with the evolution of parthenogenesis. This hypothesis is supported by the fact
that chromosome pairing and genetic recombination occurs only during female meiosis, while chromosomes do not pair during
male meiosis.
Accepted: 27 December 2000 相似文献
995.
996.
997.
The present study showed that sphingosine 1-phosphate (SPP) induced rapid stimulation of phospholipase D (PLD) in skeletal muscle C2C12 cells. The effect was receptor-mediated since it was fully inhibited by pertussis toxin. All known SPP-specific receptors, Edg-1, Edg-3 and AGR16/H218, resulted to be expressed in C2C12 myoblasts, although at a different extent. SPP-induced PLD activation did not involve membrane translocation of PLD1 or PLD2 and appeared to be fully dependent on protein kinase C (PKC) catalytic activity. SPP increased membrane association of PKCalpha, PKCdelta and PKClambda, however, only PKCalpha and PKCdelta played a role in PLD activation since low concentrations of GF109203X and rottlerin, a selective inhibitor of PKCdelta, prevented PLD stimulation. 相似文献
998.
Francesca Orso Fiorella Balzac Marco Marino Antonio Lembo Saverio Francesco Retta Daniela Taverna 《Biochemical and biophysical research communications》2013
miR-21 is overexpressed in tumors and it displays oncogenic activity. Here, we show that expression of miR-21 in primary tumors anticorrelates with KRIT1/CCM1, an interacting partner of the Ras-like GTPase Rap1, involved in Cerebral Cavernous Malformations (CCM). We present evidences that miR-21 silences KRIT1 by targeting its mRNA 3′UTR and that this interaction is involved in tumor growth control. In fact, miR-21 over-expression or KRIT1 knock-down promote anchorage independent tumor cell growth compared to controls, whereas the opposite is observed when anti-miR-21 or KRIT1 overexpression are employed. Our findings suggest that miR-21 promotes tumor cell growth, at least in part, by down-modulating the potential tumor suppressor KRIT1. 相似文献
999.
Mario Stampanoni Bassi Tommaso Nuzzo Luana Gilio Mattia Miroballo Alessia Casamassa Fabio Buttari Paolo Bellantonio Roberta Fantozzi Giovanni Galifi Roberto Furlan Annamaria Finardi Arianna De Rosa Anna Di Maio Francesco Errico Diego Centonze Alessandro Usiello 《Journal of neurochemistry》2021,159(5):857-866
1000.