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41.
From the root bark of Millettia pervilleana, which had shown significant cytotoxic activity, a 3-phenylcoumarin, named pervilleanine, two new pterocarpans, pervilline and pervillinine, and one known, emoroidocarpan, were isolated in addition to rotenone and 3alpha-hydroxyrotenone. The anticancer activity of two previously isolated isoflavanones, pervilleanone and 3'-O-demethylpervilleanone is reported. 相似文献
42.
Klinger FG Scaldaferri ML Di Carlo A Baiocchi M Coletta M Cossu G De Felici M 《The International journal of developmental biology》2003,47(4):303-305
Primordial germ cells are the only stem cells that retain true developmental totipotency after gastrulation, express markers typical of totipotent/pluripotent status and are able both in vivo and in vitro to give rise to pluripotent stem cells as EC and EG cells. We have therefore explored the possibility of the trans-differentiation of mouse PGCs to a myogenic lineage by transplanting them directly or after in vitro culture into a regenerating muscle and by culturing them on monolayers of differentianting muscle cells. The results obtained suggest that mouse PGCs may trans-differentiate into myogenic cells, provided that their somatic environment is preserved. This occurs at an estimated frequency of 0.01%, which is no higher than that reported for stem cells of adult tissues. 相似文献
43.
44.
With the use of the esophageal balloon technique, the workingcapacity of the respiratory muscles was assessed in four normal subjects by measuring the work per breath (W) and respiratory power() during maximal voluntary ventilationwith imposed respiratory frequencies (f) ranging from 20 to 273 cycles/min. Measurements were made in a body plethysmograph to assessthe work wasted as a result of alveolar gas compressibility(Wg'). In line with other types of human voluntary muscleactivity, W decreased with increasing f, whereas exhibited a maximum at f of ~100cycles/min. Up to this f value, Wg' was small relative to W. Withfurther increase in f, the Wg'/W ratio increased progressively,amounting to 8-22% of at f of 200 cycles/min. 相似文献
45.
46.
Summary Microstratigraphic, sedimentological, and taphonomic features of the Ferraz Shell Bed, from the Upper Permian (Kazanian-Tatarian?)
Corumbataí Formation of Rio Claro Region (the Paraná Basin, Brazil), indicate that the bed consists of four distinct microstratigraphic
units. They include, from bottom to top, a lag concentration (Unit 1), a partly reworked storm deposit (Unit 2), a rapidly
deposited sandstone unit with three thin horizons recording episodes of reworking (Unit 3), and a shell-rich horizon generated
by reworking/winnowing that was subsequently buried by storm-induced obrution deposit (Unit 4). The bioclasts of the Ferraz
Shell Bed represent exclusively bivalve mollusks.Pinzonellaillusa andTerraia aequilateralis are the dominant species. Taphonomic analysis indicates that mollusks are heavily time-averaged (except for some parts of
Unit 3). Moreover, different species are time-averaged to a different degree (disharmonious time-averaging). The units differ
statistically from one another in their taxonomic and ecological composition, in their taphonomic pattern, and in the size-frequency
distributions of the two most common species. Other Permian shell beds of the Paraná Basin are simílar to the Ferraz Shell
Bed in their faunal composition (they typically contain similar sets of 5 to 10 bivalve species) and in their taphonomic,
sedimentologic, and microstratigraphic characteristics. However, rare shell beds that include 2–3 species only and are dominated
by articulated shells preserved in life position also occur. Diversity levels in the Permian benthic associations of the Paraná
Basin were very low, with the point diversity of 2–3 species and with the within-habitat and basin-wide (alpha and gamma)
diversities of 10 species, at most. The Paraná Basin benthic communities may have thus been analogous to low-diversity bivalve-dominated
associations of the present-day Baltic Sea. The ‘Ferraz-type’ shell beds of the Paraná Basin represent genetically complex
and highly heterogeneous sources of paleontological data. They are cumulative records of spectra of benthic ecosystems time-averaged
over long periods of time (102–104 years judging from actualistic research). Detailed biostratinomic reconstructions of shell beds can not only offer useful
insights into their depositional histories, but may also allow paleoecologists to optimize their sampling designs, and consequently,
refine paleoecological and paleoenvironmental interpretations. 相似文献
47.
ATM and the catalytic subunit of DNA-dependent protein kinase activate NF-kappaB through a common MEK/extracellular signal-regulated kinase/p90(rsk) signaling pathway in response to distinct forms of DNA damage 下载免费PDF全文
Panta GR Kaur S Cavin LG Cortés ML Mercurio F Lothstein L Sweatman TW Israel M Arsura M 《Molecular and cellular biology》2004,24(5):1823-1835
We have identified a novel pathway of ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PK) signaling that results in nuclear factor kappaB (NF-kappaB) activation and chemoresistance in response to DNA damage. We show that the anthracycline doxorubicin (DOX) and its congener N-benzyladriamycin (AD 288) selectively activate ATM and DNA-PK, respectively. Both ATM and DNA-PK promote sequential activation of the mitogen-activated protein kinase (MAPK)/p90(rsk) signaling cascade in a p53-independent fashion. In turn, p90(rsk) interacts with the IkappaB kinase 2 (IKK-2) catalytic subunit of IKK, thereby inducing NF-kappaB activity and cell survival. Collectively, our findings suggest that distinct members of the phosphatidylinositol kinase family activate a common prosurvival MAPK/IKK/NF-kappaB pathway that opposes the apoptotic response following DNA damage. 相似文献
48.
Brandolini L Allegretti M Berdini V Cervellera MN Mascagni P Rinaldi M Melillo G Ghezzi P Mengozzi M Bertini R 《European cytokine network》2003,14(1):20-26
Carbocysteine lysine salt monohydrate (SCMC-Lys) is a well-known mucoactive drug whose therapeutic efficacy is commonly related to the ability of SCMC-Lys to replace fucomucins by sialomucins. The aim of this study was to determine if SCMC-Lys could exert an anti-oxidant action by scavenging reactive oxygen intermediates (ROIs). Our results show that SCMC-Lys proved effective as a selective scavenger of hypochlorous acid (HOCl) and hydroxyl radical (OH.), this effect being related to the reactivity of the SCMC tioether group. The scavenger activity of SCMC-Lys was observed in free cellular system as well as in activated human polymorphonuclear neutrophils (PMNs). SCMC-Lys scavenger activity on HOCl was paralleled by a powerful protection from HOCl-mediated inactivation of alpha1-antitripsin (alpha1-AT) inhibitor, the main serum protease inhibitor. Production of interleukin-(IL-)8, a major mediator of PMN recruitment in inflammatory diseases, is known to be mediated by intracellular OH. SCMC-Lys significantly reduced IL-8 production on stimulated human peripheral blood mononuclear cells (PBMCs) in the same range of concentrations affecting OH. activity. It is concluded that SCMC-Lys could exert, in addition to its mucoactive capacity, an anti-oxidant action, thus contributing to the therapeutic efficacy of SCMC-Lys. 相似文献
49.
Alessandro Marcello 《Plant biosystems》2013,147(4):765-772
Abstract From March 1988 to April 1989 a survey was carried out on the phytoplankton of Lake Bidighinzu, a hypertrophic reservoir in Northern Sardinia. The purpose of this work was to assess the general limnological conditions of the reservoir after a diversion of the urban and industrial wastes. The dynamics of chlorophyll a, and the structure and composition of the phytoplankton density and of its biomass in the study period were determined. Moreover the found trends for trasparency, temperature, conductivity, alkalinity, pH, dissolved oxygen, reactive and total phosphorus, nitrate, nitrite, ammonium nitrogen, and reactive silica are reported. The effect of water aeration on the dynamics of the other parameters is discussed. 相似文献
50.
Monteforte R Santillo A Di Giovanni M D'Aniello A Di Maro A Chieffi Baccari G 《Amino acids》2009,37(4):653-664
In this paper, the role of d-aspartate in the rat Harderian gland (HG) was investigated by histochemical, ultrastructural, and biochemical analyses. In
this gland, substantial amounts of endogenous d-Asp were detected, along with aspartate racemases that convert d-Asp to l-Asp and vice versa. We found that the gland was capable of uptaking and accumulating exogenously administered d-Asp. d-Asp acute treatment markedly increased lipid and porphyrin secretion and induced a powerful hyperaemia in inter-acinar interstitial
tissue. Since d-Asp is known to be recognized by NMDA receptors, the expression of such receptors in rat HG led us to the hypothesis that
d-Asp acute treatment induced the activation of the extracellular signal-regulated protein kinase (ERK) and nitric oxide synthase
(NOS) pathways mediated by NMDA. Interestingly, as a result of enhanced oxidative stress due to increased porphyrin secretion,
the revealed activation of the stress-activated protein kinase/c-jun N-terminal kinase (SAPK/JNK) pro-apoptotic pathway was
probably triggered by the gland itself to preserve its cellular integrity. 相似文献