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21.
Roberto MacChiarelli Luca Bondioli Laura Censi Margarita Kristoff Hernaez Loretana Salvadei Alessandra Sperduti 《American journal of physical anthropology》1994,95(1):77-83
Little attention has been devoted to assessing the reproducibility of (paleo)pathological observations. Harris lines (HL) are among the markers most used to determine chronology of stresses suffered during growth. Nevertheless, their scoring entails remarkable methodological difficulty. Bone sections (S) and radiographs (R) of 29 adult tibiae of archeological provenance (medieval) were scored for HL by five observers. At regular intervals of time, each observer gave two independent counts on both series. Results show a) a substantial interobserver disagreement of HL estimates for both sectional and radiographic records, and b) a high level of intraobserver error. © 1994 Wiley-Liss, Inc. 相似文献
22.
Guerrini Franca; Lombini Alessandra; Bizarri Mariachiara; Pupillo Paolo 《Journal of experimental botany》1994,45(9):1227-1233
Cell suspension cultures of Beta vulgaris L., treated with calciumchelators or untreated, were used to characterize pyndine nucleotide-dependentdiaphorases of microsomes. The microsomal activity of NADH-dependentduroquinone reductase from cultures treated with 10 mM Na2EGTAfor 24 h increased by a factor of 1.8 with respect to controlmicrosomes, and was mainly associated with particles of d=1.17gml1. NADPH-duroquinone reductase and NADH-ferricyanidereductase activities showed smaller increases. Bacterial protein-lipopolysaccharidecomplexes (prLPS) also promoted the increase of microsomal diaphorases;CaEGTA was Ineffective. EGTA effects on enzymes of supernatantand mitochondria were negligible, although Na2EGTA treatmentinduced cell aggregation and strong acidification of the medium. When microsomes from control cultures were solubilized with1% LPC and fractionated in high-efficiency gel permeation columns(FPLC) the diaphorase activities were found associated to threemajor proteins: (i) NADH-specific quinone reductase (NADH-QR)of 340 kDa; (ii) pyndine nucleotide-nonspecific quinone reductase(NAD(P)H-QR) of 85 kDa also having ferricyanide reductase activity;(iii) NADH-specific ferricyanide reductase (NADH-FCR) of 38kDa. The microsomes from EGTA-treated cells also showed a highlyactive NADH-QR having a larger molecular mass (440 kDa) thanin control cells. NAD(P)H-QR also showed increased activity.We conclude that external Ca2+ chelation induces changes indehydrogenase components in microsomes. Furthermore, prLPS probablyexert part of their effect on plants through Ca2+ chelation. Key words: Beta vulgaris, cell cultures, calcium chelators, diaphorase, NAD(P)H-dehydrogenase, lipopolysaccharide, EGTA, quinone reductase 相似文献
23.
Cecilia Del Casino Yi-Qin Li Alessandra Moscatelli Monica Scali Antonio Tiezzi Mauro Cresti 《Biology of the cell / under the auspices of the European Cell Biology Organization》1993,79(2):125-132
Summary— The distribution of microtubules was investigated in Nicotiana tabacum pollen tubes at different stages of tube growth by immunofluorescence microscopy. Using specific antibodies, the presence of microtubules consisting of different tubulin isoforms was tested. α-, β- and tyrosinated α-tubulin were present within the tube, whereas the acetylated form was lacking. The presence of tubulin subunits in pollen tube extracts was also investigated by immunoblotting analyses. The use of a confocal laser scanning microscope integrated with computer-assisted imaging, allowed a detailed visualization of the microtubule distribution and organization. Cytoplasmic microtubules organized as short bundles with various orientations were detected at the apex of long tubes. 相似文献
24.
Xin-Min Li† Jin Qi Augusto V. Juorio Alan A. Boulton 《Journal of neurochemistry》1993,61(4):1573-1576
Abstract: Gliosis is commonly observed in the CNS following tissue damage, and it also occurs in aging and in many neurodegen-erative diseases. Glial fibrillary acidic protein (GFAP) accumulation is a prominent feature of astrocytic gliosis. An inhibition or delay in GFAP synthesis could mitigate scar formation and thus reduce the formation of a physical barrier. The consequence of this would be to allow neurons and oligodendrocytes to reestablish a functional environment. (—)-Deprenyl, a specific monoamine oxidase (MAO) B inhibitor, has been used as an effective antipar-kinsonian drug, and it has been reported to possess neuroprotective and neurorescue properties. Using northern and slot blots to detect GFAP mRNA in C6 glioma cells, we have demonstrated that (—)-deprenyl decreases the abundance of GFAP mRNA in a time- and dose-dependent manner. The effect seems to be specific to MA0 B inhibitors because (+)-deprenyl and clorgyline exhibit no effect. This study indicates therefore that (-)-deprenyl may be useful for regulating astrogliosis following CNS injury as well as in some neurodegenerative diseases. 相似文献
25.
Hendrik Wunderlich Roque Augusto Castro Alvaro Holger Wenschuh Karsten Schnatbaum 《Journal of peptide science》2023,29(11):e3496
Peptide purification by high-performance liquid chromatography (HPLC) is associated with high solvent consumption, relatively large effort and lack of efficient parallelization. As an alternative, many catch-and-release (c&r) purification methods have been developed over the last decades to enable the efficient parallel purification of peptides originating from solid-phase peptide synthesis (SPPS). However, with one exception, none of the c&r systems has been widely established in industry and academia until today. Herein, we present an entirely new chromatography-free purification concept for peptides synthesized on a solid support, termed reactive capping purification (RCP). The RCP method relies on the capping of truncation peptides arising from incomplete coupling of amino acids during SPPS with a reactive tag. The reactive tag contains a masked functionality that, upon liberation during cleavage from the resin, enables straightforward purification of the peptide by incubation with a resin-bound reactive moiety. In this work, two different reactive tags based on masked thiols were developed. Capping with these reactive tags during SPPS led to effective modification of truncated sequences and subsequent removal of the latter by chemoselective reaction with a maleimide-functionalized solid support. By introducing a suitable protecting group strategy, the thiol-based RCP method described here could also be successfully applied to a thiol-containing peptide. Finally, the purification of a 15-meric peptide by the RCP method was demonstrated. The developed method has low solvent consumption, has the potential for efficient parallelization, uses readily available reagents, and is experimentally simple to perform. 相似文献
26.
Othman Al Musaimi Sophie V. Morse Lucia Lombardi Simona Serban Alessandra Basso Daryl R. Williams 《Journal of peptide science》2023,29(2):e3448
Successful manual synthesis of the TD2.2 peptide acting as a blood–brain barrier shuttle was achieved. TD2.2 was successfully synthesised by sequential condensation of four protected peptide fragments on solid-phase settings, after several unsuccessful attempts using the stepwise approach. These fragments were chosen to minimise the number of demanding amino acids (in terms of coupling, Fmoc removal) in each fragment that are expected to hamper the overall synthetic process. Thus, the hydrophobic amino acids as well as Arg(Pbf) were strategically spread over multiple fragments rather than having them congested in one fragment. This study shows how a peptide that shows big challenges in the synthesis using the common stepwise elongation methodology can be synthesised with an acceptable purity. It also emphasises that choosing the right fragment with certain amino acid constituents is key for a successful synthesis. It is worth highlighting that lower amounts of reagents were required to synthesise the final peptide with an identical purity to that obtained by the automatic synthesiser. 相似文献
27.
Bruno Moises de Matos Marco Augusto Stimamiglio Alejandro Correa Anny Waloski Robert 《World journal of stem cells》2023,15(5):453-465
Extracellular vesicles (EVs) are nanometric particles that enclose cell-derived bioactive molecules in a lipid bilayer and serve as intercellular communication tools. Accordingly, in various biological contexts, EVs are reported to engage in immune modulation, senescence, and cell proliferation and differentiation. Therefore, EVs could be key elements for potential off-the-shelf cell-free therapy. Little has been studied regarding EVs derived from human pluripotent stem cells (hPSC-EVs), even though hPSCs offer good opportunities for induction of tissue regeneration and unlimited proliferative ability. In this review article, we provide an overview of studies using hPSC-EVs, focusing on identifying the conditions in which the cells are cultivated for the isolation of EVs, how they are characterized, and applications already demonstrated. The topics reported in this article highlight the incipient status of the studies in the field and the significance of hPSC-EVs’ prospective applications as PSC-derived cell-free therapy products. 相似文献
28.
João Ricardo Sato Claudinei Eduardo Biazoli Ana Paula Arantes Bueno Arthur Caye Pedro Mario Pan Marcos Santoro Jessica Honorato-Mauer Giovanni Abrahão Salum Marcelo Queiroz Hoexter Rodrigo Affonseca Bressan Andrea Parolin Jackowski Euripedes Constantino Miguel Sintia Belangero Luis Augusto Rohde 《Genes, Brain & Behavior》2023,22(2):e12838
29.
Augusto C. Franco Angela Haag-Kerwer Britta Herzog Thorsten E. E. Grams Erika Ball Eduardo A. de Mattos Fabio R. Scarano Suzanne Barreto Maria A. Garcia Andre Mantovani Ulrich Lüttge 《Trees - Structure and Function》1996,10(6):359-365
Sandy plains are characteristic of the coastal region of Brazil. We investigated the diel patterns of changes in organic acid levels, leaf conductance and chlorophylla fluorescence for sun-exposed and shaded plants ofClusia hilariana, one of the dominant woody species in the sandy coastal plains of northern Rio de Janeiro state. Both exposed and shaded plants showed a typical CAM pattern with considerable diel oscillations in organic acid levels. The degradation of both malic and citric acids during the midday stomatal closure period could lead to potential CO2 fixation rates of 28 mol m-2 s-1 in exposed leaves. Moreover, exposed leaves exhibited large increases in total non-photochemical quenching (qN) accompanied by a substantial decrease in effective quantum yield during the course of the day. However, these potential high rates of CO2 fixation and the increases inqn of exposed plants were not enough to maintain the primary electron acceptor of photosystem II (qA) in a low reduction state, similar to that of shaded plants. As a result, there was a moderate increase in the reduction state of qA throughout the day. Most of the decline in photochemical efficiency of exposed leaves ofC. hilariana was reversible, as evidenced by the high levels of pre-dawn potential quantum yields (Fv/Fm) and their rapid recovery after sunset. However, the depletion of the organic acid pool in the afternoon resulted in an accentuated subsequent drop in Fv/Fm, suggesting that prolonged periods of water stress accompanied by high irradiance levels may expose plants ofC. hilariana in unprotected habitats to the danger of photoinhibition. 相似文献
30.
The bifurcations of a periodically forced predator-prey model (the chemostat model), with a prey feeding on a limiting nutrient,
are numerically detected with a continuation technique. Eight bifurcation diagrams are produced (one for each parameter in
the model) and shown to be topologically equivalent. These diagrams are also equivalent to those of the most commonly used
predator-prey model (the Rosenzweig-McArthur model). Thus, all basic modes of behavior of the two main predator-prey models
can be explained by means of a single bifurcation diagram. 相似文献