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591.
Athayde Tonhasca Jr. John C. Palumbo David N. Byrne 《Entomologia Experimentalis et Applicata》1994,72(3):265-272
We measured the effect of insecticide applications on the distribution patterns of the sweet potato whitefly,Bemisia tabaci (Gennadius), in fields of cantaloupe,Cucumis melo L., in Yuma, Arizona. Whitefly infestations were measured by counts of adults, eggs, first to mid/fourth instars, and late-fourth
instars (‘red-eyed’) nymphs. Adults were sampled from the entire leaf, and immature stages were counted in a 1-cm2 area of a leaf. The indicesb (Power Law), β (Patchiness regression) and I
d
(Morisita) indicated that all life stages were aggregated, but results for the three indices were not similar for determining
the relative aggregation levels between treatments. In general, indices β andI
d
indicated higher aggregation in insecticide-treated fields, whereasb had mixed results. The Morisita index was sensitive to a few unusually high means among a series of low densities in the
treatment plots, what could be attributed to refuges due to failure in the insecticide applications. Despite the usefulness
of the Power Law and the Patchiness regression for describing the relationship between spatial or temporal variability and
mean densities, we suggest thatI
d
is more appropriate for expression of spatial distribution because it is based on a precise definition of aggregation. 相似文献
592.
593.
M. Palumbo C. Antonello I. Viano M. Santiano O. Gia S. Gastaldi S.Marciani Magno 《Chemico-biological interactions》1983,44(3):207-218
Two anthracenedione derivatives [1 - (ω - diethylaminopropylamido) - 4 - hydroxy - 9,10 - anthracenedione hydrochloride (I) and 1 - (ω - diethylamino-propylamido) - 2 - methoxy - 4 - hydroxy - 9,10 - anthracenedione hydrochloride (II)], having an electron-rich planar chromophore and an amino-substituted side chain, have been synthesized. Their binding ability to DNA was investigated by means of spectroscopic, equilibrium dialysis and fluorescence measurements. Their inhibition efficiency on nucleic acid synthesis was also evaluated both in mouse and human cells. Our results indicate that, in comparison with adriamycin, compound I shows a slightly weaker complexation ability to DNA, while compound II interacts with DNA at a substantially lower level. These data match quite well with the biological response on the inhibition of DNA and RNA synthesis exhibited by the above mentioned compounds; in fact compound I is slightly less efficient than adriamycin and about ten times more efficient than compound II. The close relationship between the results of physicochemical and biological studies is discussed. 相似文献
594.
595.
596.
Staphylococcus aureus 196E added to a beef sausage containing starter culture and 0.5 to 2.0% glucose and incubated at 35 degrees C was unable to grow when plated on tryptic soy agar (TSA) containing 7.5% NaCl. The injury, presumed to be due to the lactic acid produced during fermentation, was more pronounced at the lower concentrations of glucose (and lower acid levels). In the absence of glucose and/or starter culture, no injury was observed. When sausages containing S. aureus injured by fermentation at 35 degrees C were incubated at 5 degrees C, the counts on TSA (measures both injured and uninjured cells) and TSA containing 7.5% NaCl (measures uninjured cells only) remained constant; however, upon reincubation of the cold-stored sausage at 35 degrees C, the staphylococcus counts on TSA and TSA containing 7.5% NaCl and were similar to the counts of S. aureus present in fermenting sausages that had never been subjected to 5 degrees C. The demonstration of acid injury indicated that the injury phenomenon must be considered when determining numbers of viable S. aureus in fermented sausages. 相似文献
597.
Chiara Chiabrando Fausto Avanzini Claudia Rivalta Fabio Colombo Roberto Fanelli Gaetana Palumbo Maria Carla Roncaglioni 《Trials》2002,3(1):5-7
Background
Antioxidant supplementation with vitamin E had no effect in the prevention of cardiovascular diseases (CVD) in three recent large, randomized clinical trials. In order to reassess critically the role of vitamin E in CVD prevention, it is important to establish whether these results are related to a lack of antioxidant action. 相似文献598.
599.
Domenica Musumeci Margherita Valente Domenica Capasso Rosanna Palumbo Matthias Grlach Michaela Schmidtke Roland Zell Giovanni N. Roviello Roberto Sapio Carlo Pedone Enrico M. Bucci 《Journal of peptide science》2006,12(3):161-170
Targeting regulatory RNA regions to interfere with the biosynthesis of a protein is an intriguing alternative to targeting a protein itself. Regulatory regions are often unique in sequence and/or structure and, thus, ideally suited for specific recognition with a low risk of undesired side effects. Targeting regulatory RNA elements, however, is complicated by their complex three-dimensional structure, which poses kinetic and thermodynamic constraints to the recognition by a complementary oligonucleotide. Oligonucleotide mimics, which shift the thermodynamic equilibrium towards complex formation and yield stable complexes with a target RNA, can overcome this problem. Peptide nucleic acids (PNA) represent such a promising class of molecules. PNA are very stable, non-ionic compounds and they are not sensitive to enzymatic degradation. Yet, PNA form specific base pairs with a target sequence. We have designed, synthesised and characterised PNA able to enter infected cells and to bind specifically to a control region of the genomic RNA of coxsackievirus B3 (CVB3), which is an important human pathogen. The results obtained by studying the interaction of such PNA with their RNA target, the entrance into the cell and the viral inhibition are herein presented. 相似文献
600.
M. Palumbo A. Cosani M. Terbojevich E. Peggion 《International journal of biological macromolecules》1981,3(2):91-96
Poly(d-phenylglycine) and poly(d-cyclohexylglycine) containing phenyl and cyclohexyl rings bound to the α-carbon of the polypeptide chain, have been synthesized. Circular dichroism measurements show that both polymers undergo a conformational transition from the random-coil form to an ordered form, upon addition of water, ethanol or trifluoroethanol to sulphuric acid solutions. Solid state measurements indicate that the ordered structures of poly(d-phenylglycine) and poly(d-cyclohexylglycine) are of the β-type. While for the former the antiparallel arrangement is predominant, for the latter there seems to be a greater tendency towards the parallel form. The ordered form of poly(d-cyclohexylglycine) is slightly more stable than the corresponding form of poly(d-phenylglycine) in all the above solvent systems. This can be interpreted in terms of stronger non covalent bond formation in the former polypeptide. Our results have been compared with literature on poly(l-phenylalanine) and poly(l-cyclohexylalanine). 相似文献