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91.
Sergei Andreev Igor Andreev Elena Nikolaeva Anna Petrukhina Vladimir Zemskov Mariam Vafina 《Letters in Peptide Science》1998,5(2-3):63-66
The V3 loop from HIV-1 envelope glycoprotein gp120 is involved in viral entry and determines the cellular tropism and HIV-1-induced cell–cell fusion. Earlier we have shown that V3 loop peptides representing the sequences of syncytia-inducing HIV strains have high membranotropic activity. These peptides caused the lysis of liposomes of various lipid compositions, could fuse negatively charged liposomes and induced hemolysis of erythrocytes. In contrast, peptides mimicking the sequences of non-syncytia-inducing viruses showed no lytic or fusion activities at the same concentrations. Now we have found that the V3 loop synthetic peptides containing the conserved GPGR region, derived from T-lymphotropic strains (BRU and MN), as opposed to peptides containing the GPGQ region, are able to cause a pronounced membrane permeabilization (dissipation of the pH and the of human peripheral blood lymphocytes, erythrocytes and plasma membrane vesicles at micromolar concentrations with a dose-dependent kinetics. Analysis of the secondary structures of the peptides by circular dichroism revealed conformational changes in V3 loop peptides depending on solvent hydrophobicity: from random coil in water to an -helix/-sheet conformation in trifluoroethanol. Such structural changes of the V3 loop together with the membrane insertion of the gp41 N-terminal fusion peptide may promote the formation of the fusion pore during virus–cell fusion. 相似文献
92.
Our review recognizes 15 species of the integripennis species group of Geocharidius from Nuclear Central America, include three species previously described (Geocharidius
gimlii Erwin, Geocharidius
integripennis (Bates) and Geocharidius
zullinii Vigna Taglianti) and 12 described here as new. They are: Geocharidius
andersoni
sp. n. (type locality: Chiapas, Chiapas Highlands, Cerro Huitepec) and Geocharidius
vignatagliantii
sp. n. (type locality: Chiapas, Motozintla, Sierra Madre de Chiapas, Benito Juárez) from Mexico; Geocharidius
antigua
sp. n. (type locality: Sacatepéquez, 5 km SE of Antigua), Geocharidius
balini
sp. n. (type locality: Suchitepéquez, 4 km S of Volcan Atitlán), Geocharidius
erwini
sp. n. (type locality: Quiché Department, 7 km NE of Los Encuentros), Geocharidius
jalapensis
sp. n. (type locality: Jalapa Department, 4 km E of Mataquescuintla), Geocharidius
longinoi, sp. n. (type locality: El Progreso Department, Cerro Pinalón), and Geocharidius
minimus
sp. n. (type locality: Sacatepéquez Department, 5 km SE of Antigua) from Guatemala; and Geocharidius
celaquensis
sp. n. (type locality: Lempira Department, Celaque National Park), Geocharidius
comayaguanus
sp. n. (type locality: Comayagua Department, 18 km ENE of Comayagua), Geocharidius
disjunctus
sp. n. (type locality: Francisco Morazán, La Tigra National Park), and Geocharidius
lencanus
sp. n. (type locality: Lempira Department, Celaque National Park) from Honduras. For all members of the group, adult structural characters, including male and female genitalia, are described, and a taxonomic key for all members of the integripennis species group is presented based on these characters. Behavioral and biogeographical aspects of speciation in the group are discussed, based on the morphological analysis. In all cases of sympatry, pairs of closely related species show greater differences in sizes than pairs of more remotely related species. Integripennis group species occupy six different montane areas at elevations above 1300m, with no species shared among them. Major faunal barriers in the region limiting present species distributions include the Motagua Fault Zone and a gap between the Guatemalan Cordillera volcanic chain and the Honduran Interior Highlands no higher than 900m in elevation. Highest species diversity is in the Guatematan Cordillera (six species), second highest in the Honduran Interior Highlands area (four species). 相似文献
93.
Prevalence of intron gain over intron loss in the evolution of paralogous gene families 总被引:14,自引:2,他引:14
The mechanisms and evolutionary dynamics of intron insertion and loss in eukaryotic genes remain poorly understood. Reconstruction of parsimonious scenarios of gene structure evolution in paralogous gene families in animals and plants revealed numerous gains and losses of introns. In all analyzed lineages, the number of acquired new introns was substantially greater than the number of lost ancestral introns. This trend held even for lineages in which vertical evolution of genes involved more intron losses than gains, suggesting that gene duplication boosts intron insertion. However, dating gene duplications and the associated intron gains and losses based on the molecular clock assumption showed that very few, if any, introns were gained during the last ~100 million years of animal and plant evolution, in agreement with previous conclusions reached through analysis of orthologous gene sets. These results are generally compatible with the emerging notion of intensive insertion and loss of introns during transitional epochs in contrast to the relative quiet of the intervening evolutionary spans. 相似文献
94.
Elisabet Bjanes Reyna Garcia Sillas Rina Matsuda Benjamin Demarco Timothe Fettrelet Alexandra A. DeLaney Opher S. Kornfeld Bettina L. Lee Eric M. Rodríguez Lpez Daniel Grubaugh Meghan A. Wynosky-Dolfi Naomi H. Philip Elise Krespan Dorothy Tovar Leonel Joannas Daniel P. Beiting Jorge Henao-Mejia Brian C. Schaefer Kaiwen W. Chen Petr Broz Igor E. Brodsky 《PLoS pathogens》2021,17(10)
Cell death plays a critical role in inflammatory responses. During pyroptosis, inflammatory caspases cleave Gasdermin D (GSDMD) to release an N-terminal fragment that generates plasma membrane pores that mediate cell lysis and IL-1 cytokine release. Terminal cell lysis and IL-1β release following caspase activation can be uncoupled in certain cell types or in response to particular stimuli, a state termed hyperactivation. However, the factors and mechanisms that regulate terminal cell lysis downstream of GSDMD cleavage remain poorly understood. In the course of studies to define regulation of pyroptosis during Yersinia infection, we identified a line of Card19-deficient mice (Card19lxcn) whose macrophages were protected from cell lysis and showed reduced apoptosis and pyroptosis, yet had wild-type levels of caspase activation, IL-1 secretion, and GSDMD cleavage. Unexpectedly, CARD19, a mitochondrial CARD-containing protein, was not directly responsible for this, as an independently-generated CRISPR/Cas9 Card19 knockout mouse line (Card19Null) showed no defect in macrophage cell lysis. Notably, Card19 is located on chromosome 13, immediately adjacent to Ninj1, which was recently found to regulate cell lysis downstream of GSDMD activation. RNA-seq and western blotting revealed that Card19lxcn BMDMs have significantly reduced NINJ1 expression, and reconstitution of Ninj1 in Card19lxcn immortalized BMDMs restored their ability to undergo cell lysis in response to caspase-dependent cell death stimuli. Card19lxcn mice exhibited increased susceptibility to Yersinia infection, whereas independently-generated Card19Null mice did not, demonstrating that cell lysis itself plays a key role in protection against bacterial infection, and that the increased infection susceptibility of Card19lxcn mice is attributable to loss of NINJ1. Our findings identify genetic targeting of Card19 being responsible for off-target effects on the adjacent gene Ninj1, disrupting the ability of macrophages to undergo plasma membrane rupture downstream of gasdermin cleavage and impacting host survival and bacterial control during Yersinia infection. 相似文献
95.
The point of maximum cell water volume excursion in case of presence of an impermeable solute 总被引:4,自引:0,他引:4
Katkov II 《Cryobiology》2002,44(3):193-203
A relativistic permeability model of cell osmotic response (Cryobiology 40:64-83; 41:366-367) is applied to a two-solute system with one impermeable solute. The use of the normalized water volume (w), and the amount of intracellular permeable solute (x), which is the product of the water volume and intracellular osmolality (y), as the main variables allowed us to obtain a homogeneous differential equation dx(Delta)/dw(Delta)=f(x(Delta)/w(Delta)), where w(Delta)=w-w(f), x(Delta)=x-x(f), and f refers to the final (equilibrium) values. The solution of this equation is an explicit function, w(Delta)=g(x(Delta)), which is given in the text. This approach allows us to obtain an analytical (exact) expression of the water volume at the moment of the maximum excursion (water extremum w(m)). Results are compared with numeration of basic osmotic equations and with approximation given in (Cryobiology 40:64-83). Assumption that, dw/dt approximately 0 gives good approximations of the kinetics of water and permeable CPA after the point of maximum volume excursion (the slow phase of osmotic response). Practical aspects of the relativistic permeability approach are also discussed. 相似文献
96.
97.
98.
Ovsiannikova Natalia L. Lavrushkina Svetlana V. Ivanova Anastasia V. Mazina Ludmila M. Zhironkina Oxana A. Kireev Igor I. 《Biochemistry. Biokhimii?a》2021,86(10):1288-1300
Biochemistry (Moscow) - One of the main factors associated with worse prognosis in oncology is metastasis, which is based on the ability of tumor cells to migrate from the primary source and to... 相似文献
99.
Mark Austin Hanson Lianne B. Cohen Alice Marra Igor Iatsenko Steven A. Wasserman Bruno Lemaitre 《PLoS pathogens》2021,17(8)
The fruit fly Drosophila melanogaster combats microbial infection by producing a battery of effector peptides that are secreted into the haemolymph. Technical difficulties prevented the investigation of these short effector genes until the recent advent of the CRISPR/CAS era. As a consequence, many putative immune effectors remain to be formally described, and exactly how each of these effectors contribute to survival is not well characterized. Here we describe a novel Drosophila antifungal peptide gene that we name Baramicin A. We show that BaraA encodes a precursor protein cleaved into multiple peptides via furin cleavage sites. BaraA is strongly immune-induced in the fat body downstream of the Toll pathway, but also exhibits expression in other tissues. Importantly, we show that flies lacking BaraA are viable but susceptible to the entomopathogenic fungus Beauveria bassiana. Consistent with BaraA being directly antimicrobial, overexpression of BaraA promotes resistance to fungi and the IM10-like peptides produced by BaraA synergistically inhibit growth of fungi in vitro when combined with a membrane-disrupting antifungal. Surprisingly, BaraA mutant males but not females display an erect wing phenotype upon infection. Here, we characterize a new antifungal immune effector downstream of Toll signalling, and show it is a key contributor to the Drosophila antimicrobial response. 相似文献
100.