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91.
Francesco Loreto Michela Mannozzi Christophe Maris Pamela Nascetti Francesco Ferranti Stefania Pasqualini 《Plant physiology》2001,126(3):993-1000
Isoprene is formed in and emitted by plants and the reason for this apparent carbon waste is still unclear. It has been proposed that isoprene stabilizes cell and particularly chloroplast thylakoid membranes. We tested if membrane stabilization or isoprene reactivity with ozone induces protection against acute ozone exposures. The reduction of visible, physiological, anatomical, and ultrastructural (chloroplast) damage shows that clones of plants sensitive to ozone and unable to emit isoprene become resistant to acute and short exposure to ozone if they are fumigated with exogenous isoprene, and that isoprene-emitting plants that are sensitive to ozone do not suffer damage when exposed to ozone. Isoprene-induced ozone resistance is associated with the maintenance of photochemical efficiency and with a low energy dissipation, as indicated by fluorescence quenching. This suggests that isoprene effectively stabilizes thylakoid membranes. However, when isoprene reacts with ozone within the leaves or in a humid atmosphere, it quenches the ozone concentration to levels that are less or non-toxic for plants. Thus, protection from ozone in plants fumigated with isoprene may be due to a direct ozone quenching rather than to an induced resistance at membrane level. Irrespective of the mechanism, isoprene is one of the most effective antioxidants in plants. 相似文献
92.
Roger Fuoco Patrizia Bogani Gabriele Capodaglio Massimo Del Bubba Ornella Abollino Stefania Giannarelli Maria Michela Spiriti Beatrice Muscatello Saer Doumett Clara Turetta Roberta Zangrando Vincenzo Zelano Marcello Buiatti 《Journal of plant physiology》2013
Recently our findings have shown that the integration of the gene coding for the rat gluco-corticoid receptor (GR receptor) in Nicotiana langsdorffii plants induced morphophysiological effects in transgenic plants through the modification of their hormonal pattern. Phytohormones play a key role in plant responses to many different biotic and abiotic stresses since a modified hormonal profile up-regulates the activation of secondary metabolites involved in the response to stress. In this work transgenic GR plants and isogenic wild type genotypes were exposed to metal stress by treating them with 30 ppm cadmium(II) or 50 ppm chromium(VI). Hormonal patterns along with changes in key response related metabolites were then monitored and compared. Heavy metal up-take was found to be lower in the GR plants. The transgenic plants exhibited higher values of S-abscisic acid (S-ABA) and 3-indole acetic acid (IAA), salicylic acid and total polyphenols, chlorogenic acid and antiradical activity, compared to the untransformed wild type plants. Both Cd and Cr treatments led to an increase in hormone concentrations and secondary metabolites only in wild type plants. Analysis of the results suggests that the stress responses due to changes in the plant's hormonal system may derive from the interaction between the GR receptor and phytosteroids, which are known to play a key role in plant physiology and development. 相似文献
93.
Silvia Ghirotto Francesca Tassi Erica Fumagalli Vincenza Colonna Anna Sandionigi Martina Lari Stefania Vai Emmanuele Petiti Giorgio Corti Ermanno Rizzi Gianluca De Bellis David Caramelli Guido Barbujani 《PloS one》2013,8(2)
The Etruscan culture is documented in Etruria, Central Italy, from the 8th to the 1st century BC. For more than 2,000 years there has been disagreement on the Etruscans’ biological origins, whether local or in Anatolia. Genetic affinities with both Tuscan and Anatolian populations have been reported, but so far all attempts have failed to fit the Etruscans’ and modern populations in the same genealogy. We extracted and typed the hypervariable region of mitochondrial DNA of 14 individuals buried in two Etruscan necropoleis, analyzing them along with other Etruscan and Medieval samples, and 4,910 contemporary individuals from the Mediterranean basin. Comparing ancient (30 Etruscans, 27 Medieval individuals) and modern DNA sequences (370 Tuscans), with the results of millions of computer simulations, we show that the Etruscans can be considered ancestral, with a high degree of confidence, to the current inhabitants of Casentino and Volterra, but not to the general contemporary population of the former Etruscan homeland. By further considering two Anatolian samples (35 and 123 individuals) we could estimate that the genetic links between Tuscany and Anatolia date back to at least 5,000 years ago, strongly suggesting that the Etruscan culture developed locally, and not as an immediate consequence of immigration from the Eastern Mediterranean shores. 相似文献
94.
95.
The purpose of this paper is to review the patterns of contraceptive use in Australia, using data from a nationally representative sample of 5872 women aged 18 to 49. This survey was conducted by the Australian Bureau of Statistics in 2001 as part of the National Health Survey. Results of the analysis indicate that the oral contraceptive pill and condom were the two most frequently used methods. More than 76% of the respondents reported having ever used the pill. Over 23% of women were currently using condoms; of these 80% of the condom users used them for contraception - this included 36% who used condoms for both protection against infection and for contraception - and the remainder used them only for protection. Withdrawal was the third most popular non-surgical method up to age 40. Few women used IUDs, injections or diaphragms. Just over 3% of the respondents were using natural methods with the highest rate reported among those in their 30s. The 'morning-after pill' was reported mostly by women aged 18-24; however, there was no evidence to suggest that it was being used as a primary method of birth control. Contraceptive use declined in older women who turned to sterilization for themselves and/or their partners. Use of the contraceptive pill was somewhat higher among better-educated women, but lower among less-educated women and those from non-English-speaking backgrounds. 相似文献
96.
97.
Gametogenesis of intergroup hybrids of hemiclonal frogs 总被引:1,自引:0,他引:1
Ragghianti M Bucci S Marracci S Casola C Mancino G Hotz H Guex GD Plötner J Uzzell T 《Genetical research》2007,89(1):39-45
European water frog hybrids Rana esculenta (R. ridibundaxR. lessonae) reproduce hemiclonally, by hybridogenesis: in the germ line they exclude the genome of one parental species and produce haploid gametes with an unrecombined genome of the other parental species. In the widespread L-E population system, both sexes of hybrids (E) coexist with R. lessonae (L). They exclude the lessonae genome and produce ridibunda gametes. In the R-E system, hybrid males coexist with R. ridibunda (R); they exclude either their ridibunda or their lessonae genome and produce sperm with a lessonae or with a ridibunda genome or a mixture of both kinds of sperm. We examined 13 male offspring, 12 of which were from crosses between L-E system and R-E system frogs. All were somatically hybrid. With one exception, they excluded the lessonae genome in the germ line and subsequently endoreduplicated the ridibunda genome. Spermatogonial metaphases contained a haploid or a diploid number of ridibunda chromosomes, identified through in situ hybridization to a satellite DNA marker, and by spermatocyte I metaphases containing a haploid number of ridibunda bivalents. The exception, an F1 hybrid between L-E system R. lessonae and R-E system R. ridibunda, was not hybridogenetic, showed no genome exclusion, and evidenced a disturbed gametogenesis resulting from the combination of two heterospecific genomes. None of the hybridogenetic hybrids showed any cell lines excluding the ridibunda genome, the pattern most frequent in hybrids of the R-E system, unique to that system, and essential for its persistence. A particular combination of R-E system lessonae and R-E system ridibunda genomes seems necessary to induce the R-E system type of hemiclonal gametogenesis. 相似文献
98.
Ranguelova K Girotto S Gerfen GJ Yu S Suarez J Metlitsky L Magliozzo RS 《The Journal of biological chemistry》2007,282(9):6255-6264
Catalase-peroxidase (KatG) from Mycobacterium tuberculosis, a Class I peroxidase, exhibits high catalase activity and peroxidase activity with various substrates and is responsible for activation of the commonly used antitubercular drug, isoniazid (INH). KatG readily forms amino acid-based radicals during turnover with alkyl peroxides, and this work focuses on extending the identification and characterization of radicals forming on the millisecond to second time scale. Rapid freeze-quench electron paramagnetic resonance spectroscopy (RFQ-EPR) reveals a change in the structure of the initially formed radical in the presence of INH. Heme pocket binding of the drug and knowledge that KatG[Y229F] lacks this signal provides evidence for radical formation on residue Tyr(229). High field RFQ-EPR spectroscopy confirmed a tryptophanyl radical signal, and new analyses of X-band RFQ-EPR spectra also established its presence. High field EPR spectroscopy also confirmed that the majority radical species is a tyrosyl radical. Site-directed mutagenesis, along with simulations of EPR spectra based on x-ray structural data for particular tyrosine and tryptophan residues, enabled assignments based on predicted hyperfine coupling parameters. KatG mutants W107F, Y229F, and the double mutant W107F/Y229F showed alteration in type and yield of radical species. Results are consistent with formation of a tyrosyl radical reasonably assigned to residue Tyr(229) within the first few milliseconds of turnover. This is followed by a mixture of tyrosyl and tryptophanyl radical species and finally to only a tyrosyl radical on residue Tyr(353), which lies more distant from the heme. The radical processing of enzyme lacking the Trp(107)-Tyr(229)-Met(255) adduct (found as a unique structural feature of catalase-peroxidases) is suggested to be a reasonable assignment of the phenomena. 相似文献
99.
Zerjal T Pandya A Thangaraj K Ling EY Kearley J Bertoneri S Paracchini S Singh L Tyler-Smith C 《Human genetics》2007,121(1):137-144
The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at
birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed
male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86
from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male
substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance
of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper
castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger
effective population sizes, or less strict isolation, or both.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.
Tatiana Zerjal and Arpita Pandya contributed equally to this work. 相似文献
100.
Gloria Taliani Martina Spaziante Elisa Biliotti Marina Borro Donatella Palazzo Stefania Grieco Cristiana Franchi Giancarlo Iaiani Caterina Furlan Valentina Gallinaro Maurizio Simmaco 《PloS one》2013,8(8)