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951.
Francisco de Castro Sina M. Adl Stefano Allesina Richard D. Bardgett Thomas Bolger Johnathan J. Dalzell Mark Emmerson Thomas Fleming Diego Garlaschelli Jacopo Grilli Silja Emilia Hannula Franciska de Vries Zoë Lindo Aaron G. Maule Maarja
pik Matthias C. Rillig Stavros D. Veresoglou Diana H. Wall Tancredi Caruso 《Ecology and evolution》2021,11(22):16070
Ecologists have long debated the properties that confer stability to complex, species‐rich ecological networks. Species‐level soil food webs are large and structured networks of central importance to ecosystem functioning. Here, we conducted an analysis of the stability properties of an up‐to‐date set of theoretical soil food web models that account both for realistic levels of species richness and the most recent views on the topological structure (who is connected to whom) of these food webs. The stability of the network was best explained by two factors: strong correlations between interaction strengths and the blocked, nonrandom trophic structure of the web. These two factors could stabilize our model food webs even at the high levels of species richness that are typically found in soil, and that would make random systems very unstable. Also, the stability of our soil food webs is well‐approximated by the cascade model. This result suggests that stability could emerge from the hierarchical structure of the functional organization of the web. Our study shows that under the assumption of equilibrium and small perturbations, theoretical soil food webs possess a topological structure that allows them to be complex yet more locally stable than their random counterpart. In particular, results strongly support the general hypothesis that the stability of rich and complex soil food webs is mostly driven by correlations in interaction strength and the organization of the soil food web into functional groups. The implication is that in real‐world food web, any force disrupting the functional structure and distribution pattern of interaction strengths (i.e., energy fluxes) of the soil food webs will destabilize the dynamics of the system, leading to species extinction and major changes in the relative abundances of species. 相似文献
952.
To gain a better understanding of the function of the yeast histone H1, its role in nucleosome positioning was studied. With
this objective in mind, we analyzed a chromatin region of the yeast Chromosome (Chr) IX, in which there are two closely packed
open reading frames (ORFs), POT1 and YIL161w. This locus shows a regular ladder of 13 stochastically positioned nucleosomes, which is unaffected by the absence of the
HHO1 gene. This suggests that histone H1 has no effect on nucleosome positioning in yeast.
Received: 30 December 1998 / Accepted: 6 May 1999 相似文献
953.
Dinesh Jaishankar Cormac Cosgrove Prathyaya Ramesh James Mahon Rohan Shivde Emilia R. Dellacecca Shiayin F. Yang Jeffrey Mosenson Jos A. Guevara-Patio I. Caroline Le Poole 《Cell stress & chaperones》2021,26(5):845
Developing immunosuppressive therapies for autoimmune diseases comes with a caveat that immunosuppression may promote the risk of developing other conditions or diseases. We have previously shown that biolistic delivery of an expression construct encoding inducible HSP70 (HSP70i) with one amino acid modification in the dendritic cell (DC) activating moiety 435–445 (HSP70iQ435A) to mouse skin resulted in significant immunosuppressive activity of autoimmune vitiligo, associated with fewer tissue infiltrating T cells. To prepare HSP70iQ435A as a potential therapeutic for autoimmune vitiligo, in this study we evaluated whether and how biolistic delivery of HSP70iQ435A in mice affects anti-tumor responses. We found that HSP70iQ435A in fact supports anti-tumor responses in melanoma-challenged C57BL/6 mice. Biolistic delivery of the HSP70iQ435A-encoding construct to mice elicited significant anti-HSP70 titers, and anti-HSP70 IgG and IgM antibodies recognize surface-expressed and cytoplasmic HSP70i in human and mouse melanoma cells. A peptide scan revealed that the anti-HSP70 antibodies recognize a specific C-terminal motif within the HSP70i protein. The antibodies elicited surface CD107A expression among mouse NK cells, representative of antibody-mediated cellular cytotoxicity (ADCC), supporting the concept, that HSP70iQ435A-encoding DNA elicits a humoral response to the stress protein expressed selectively on the surface of melanoma cells. Thus, besides limiting autoimmunity and inflammation, HSP70iQ435A elicits humoral responses that limit tumor growth and may be used in conjunction with immune checkpoint inhibitors to not only control tumor but to also limit adverse events following tumor immunotherapy.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12192-021-01229-x. 相似文献
954.
Emilia Mellado Charles A. Specht Phillips W. Robbins David W. Holden 《FEMS microbiology letters》1996,143(1):69-76
Abstract A chitin synthase-like gene ( chsD ) was isolated from an Aspergillus fumigatus genomic DNA library. Comparisons with the predicted amino acid sequence from chsD reveals low but significant similarity to chitin synthases, to other N acetylglucosaminyltransferases (NodC from Rhizopus spp., HasA from Streptococcus spp. and DG42 from vertebrates. A chsD− mutant strain constructed by gene disruption has a 20% reduction in total mycelial chitin content; however, no differences between the wild-type strain and the chsD− strain were found with respect to morphology, chitin synthase activity or virulence in a neutropenic murine model of aspergillosis. The results show that the chsD product has an important but inessential role in the synthesis of chitin in A. fumigatus . 相似文献
955.
Inmaculada Llamas Ana del Moral Victoria Béjar Mara Dolores Girón Rafael Salto Emilia Quesada 《FEMS microbiology letters》1997,156(2):251-257
The moderately halophilic bacterium Halomonas eurihalina strain F2-7, able to produce an exopolysaccharide, was found to contain two plasmids named pVE1 and pVE2, of 8.1 and 5.8 kb respectively. We found no evidence for the involvement of these plasmids in the expression of the mucoid phenotype. Restriction maps of both plasmids were constructed. Southern hybridization revealed similarities between them but excluded the existence of sequences homologous to other plasmids isolated from the Halomonas species. Neither pVE1 nor pVE2 displayed any homology with other plasmids isolated from moderate halophiles. The occurrence of similar plasmids in other strains of Halomonas eurihalina, isolated from hypersaline soils, has been detected. These small plasmids may be useful for the development of cloning vectors for moderately halophilic bacteria. 相似文献
956.
To study spatiotemporal regulation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK1/2) signaling cascade in living cells, a HeLa cell line in which MAPK kinase of ERK kinase (MEK) 2 (MAPK kinase) was knocked down by RNA interference and replaced with the green fluorescent protein (GFP)-tagged MEK2 was generated. In these cells, MEK2-GFP was stably expressed at a level similar to that of the endogenous MEK2 in the parental cells. Upon activation of the EGF receptor (EGFR), a pool of MEK2-GFP was found initially translocated to the plasma membrane and then accumulated in a subset of early and late endosomes. However, activated MEK was detected only at the plasma membrane and not in endosomes. Surprisingly, MEK2-GFP endosomes did not contain active EGFR, suggesting that endosomal MEK2-GFP was separated from the upstream signaling complexes. Knockdown of clathrin by small interfering RNA (siRNA) abolished MEK2 recruitment to endosomes but resulted in increased activation of ERK without affecting the activity of MEK2-GFP. The accumulation of MEK2-GFP in endosomes was also blocked by siRNA depletion of RAF kinases and by the MEK1/2 inhibitor, UO126. We propose that the recruitment of MEK2 to endosomes can be a part of the negative feedback regulation of the EGFR-MAPK signaling pathway by endocytosis. 相似文献
957.
Laura Alcazar-Fuoli Juan L. Rodríguez-Tudela Emilia Mellado 《Current fungal infection reports》2008,2(1):36-42
The incidence of fungal infections has increased over the past decade. In addition to classical pathogens, such as Aspergillus spp, new fungal species are increasingly reported. Despite the availability of new antifungals, mortality of invasive fungal
infections remains very high. The host immune status is the main factor for survival. However, most of these pathogens have
high minimum inhibitory concentrations (MICs) to antifungals, and therefore, the influence of these high MICs in the outcome
of the patients have begun to be addressed. Several strains of Aspergillus fumigatus showing resistance to itraconazole have been isolated, and the molecular-resistance mechanisms have been characterized. In
addition, attempts to correlate high MICs with patient outcome have been performed. Although correlation is far from perfect,
a clear trend between high MICs and poor outcome has been established. Resistance of fungi to antifungals is a health problem
requiring support from research agencies. 相似文献
958.
Integrin-induced epidermal growth factor (EGF) receptor activation requires c-Src and p130Cas and leads to phosphorylation of specific EGF receptor tyrosines. 总被引:21,自引:0,他引:21
Laura Moro Laura Dolce Sara Cabodi Elena Bergatto Elisabetta Boeri Erba Monica Smeriglio Emilia Turco Saverio Francesco Retta Maria Gabriella Giuffrida Mascia Venturino Jasminka Godovac-Zimmermann Amedeo Conti Erik Schaefer Laura Beguinot Carlo Tacchetti Paolo Gaggini Lorenzo Silengo Guido Tarone Paola Defilippi 《The Journal of biological chemistry》2002,277(11):9405-9414
Integrin-mediated cell adhesion cooperates with growth factor receptors in the control of cell proliferation, cell survival, and cell migration. One mechanism to explain these synergistic effects is the ability of integrins to induce phosphorylation of growth factor receptors, for instance the epidermal growth factor (EGF) receptor. Here we define some aspects of the molecular mechanisms regulating integrin-dependent EGF receptor phosphorylation. We show that in the early phases of cell adhesion integrins associate with EGF receptors on the cell membrane in a macromolecular complex including the adaptor protein p130Cas and the c-Src kinase, the latter being required for adhesion-dependent assembly of the macromolecular complex. We also show that the integrin cytoplasmic tail, c-Src kinase, and the p130Cas adaptor protein are required for phosphorylation of EGF receptor in response to integrin-mediated adhesion. We show that integrins induce phosphorylation of EGF receptor on tyrosine residues 845, 1068, 1086, and 1173, but not on residue 1148, a major site of phosphorylation in response to EGF. In addition we find that integrin-mediated adhesion increases the amount of EGF receptor expressed on the cell surface. Therefore these data indicate that integrin-mediated adhesion induces assembly of a macromolecular complex containing c-Src and p130Cas and leads to phosphorylation of specific EGF receptor tyrosine residues. 相似文献
959.
Long-term implications of industrial pollution stress on lipids composition in Scots pine (Pinus sylvestris L.) roots 总被引:1,自引:0,他引:1
The influence of pollution stress (SO2, Cu2+, Pb2+, Zn2+ and fluoride) on composition changes in cellular membranes of roots of three European of Scots pine (Pinus sylvestris L.) populations were examined. Plant material growing in three experimental areas: Kórnik relatively free of air pollution
(control), Luboń: SO2 and HF and Głogów: SO2 and heavy metals. Analysis of total phospholipids and their composition indicates that the phosphatidylcholine (PC) and phosphatidylethanolamine
(PE) were present in lower concentration in the root tissues from both polluted sites (Luboń and Głogów). The difference in
PC:PE ratio between control and both polluted sites was greater in root of Scots pine population from Russia than in the population
from Slovakia. Under pollution conditions the content of lipid soluble antioxidant α-tocopherol was lower about 220 %, in
comparison to the control. The action of pollution stress also lead to lowering of unsaturated:saturated ratio of total fatty
acid, and lower content of polyunsaturated fatty acids, linoleic acid (18:2) and eicosatrienoic acid (20:3). We concluded
that the long-term pollution stress markedly inhibited lipid biosynthesis in root tissue of Scots pine and it is probably
contribute to the reduction of productivity of forests. These results also suggest that lipid composition can be used as an
indicator of changes in tissue roots of Scots pine caused by air and/or soil long-term pollution. 相似文献