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51.
Xiaoyu Luo Hugo Mouquet Olivier Schwartz Warner C. Greene 《The Journal of biological chemistry》2021,297(4)
The progressive loss of CD4+ T cells during HIV infection of lymphoid tissues involves both the apoptotic death of activated and productively infected CD4 T cells and the pyroptotic death of large numbers of resting and abortively infected bystander CD4 T cells. HIV spreads both through cellular release of virions and cell-to-cell transmission involving the formation of virological synapses. Cell-to-cell transmission results in high-level transfer of large quantities of virions to the target cell exceeding that achieved with cell-free virions. Broadly neutralizing anti-HIV antibodies (bNAbs) binding to HIV envelope protein capably block cell-free virus spread, and when added at higher concentrations can also interdict cell-to-cell transmission. Exploiting these distinct dose–response differences, we now show that four different bNAbs block the pyroptotic death of bystander cells, but only when added at concentrations sufficient to block cell-to-cell transmission. These findings further support the conclusion that HIV killing of abortively infected bystander CD4 T cells requires cell-to-cell transfer of virions. As bNAbs attract more interest as potential therapeutics, it will be important to consider the higher concentrations of these antibodies required to block the inflammatory death of bystander CD4 T cells. 相似文献
52.
Mara C. Almeida Hugo J. Message Paulo V. Sanches Dirceu Baumgartner Robie A. Bombardelli Gilmar Baumgartner Langeani Francisco 《Journal of fish biology》2019,94(2):320-324
This study investigated the morphology, morphometric and meristic characters of 117 larval Pimelodus britskii showing early development of head, eye, barbel and snout. Body and mouth pigmentation increased throughout development; the mouth was ventrally situated in the yolk-sac stage, becoming subterminal afterwards, and an embryonic fin was visible in all four stages observed. Post-flexion larval P. bristskii are distinguished from larval P. ortmanni by having 47–50 myomeres (v. 36). 相似文献
53.
Meiring HD Kuipers B van Gaans-van den Brink JA Poelen MC Timmermans H Baart G Brugghe H van Schie J Boog CJ de Jong AP van Els CA 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(9):5636-5643
The meningococcal class I outer membrane protein porin A plays an important role in the development of T cell-dependent protective immunity against meningococcal serogroup B infection and is therefore a major component of candidate meningococcal vaccines. T cell epitopes from porin A are poorly characterized because of weak in vitro memory T cell responses against purified Ag and strain variation. We applied a novel strategy to identify relevant naturally processed and MHC class II-presented porin A epitopes, based on stable isotope labeling of Ag. Human immature HLA-DR1-positive dendritic cells were used for optimal uptake and MHC class II processing of (14)N- and (15)N-labeled isoforms of the neisserial porin A serosubtype P1.5-2,10 in bacterial outer membrane vesicles. HLA-DR1 bound peptides, obtained after 48 h of Ag processing, contained typical spectral doublets in mass spectrometry that could easily be assigned to four porin A regions, expressed at diverging densities ( approximately 30-4000 copies/per cell). Epitopes from two of these regions are recognized by HLA-DR1-restricted CD4(+) T cell lines and are conserved among different serosubtypes of meningococcal porin A. This mass tag-assisted approach provides a useful methodology for rapid identification of MHC class II presented bacterial CD4(+) T cell epitopes relevant for vaccine development. 相似文献
54.
The red tide dinoflagellate Karenia brevis (Davis) G. Hansen and Moestrup is noted for causing mass mortalities of marine organisms in the Gulf of Mexico. Most research has focused on culture isolates from the eastern Gulf of Mexico. In this investigation, we examine the effects of light, temperature and salinity on the growth rate of K. brevis from the western Gulf of Mexico. Growth rates of K. brevis were determined under various combinations of irradiance (19, 31, 52, 67, and 123 μmol m−2 s−1), salinity (25, 30, 35, 40 and 45), and temperature (15, 20, 25, and 30 °C). Maximum growth rates varied from 0.17 to 0.36 div day−1 with exponential growth rates increasing with increasing irradiance. Little or no growth was supported at 19 μmol photons m−2 s−1 for any experiment. Maximum growth rates at 15 °C were much lower than at other temperatures. Maximum growth rates of the Texas clone (SP3) fell within the range of Florida clones reported in the literature (0.17–0.36 div day−1 versus 0.2–1.0 div day−1). The Texas clone SP3 had a very similar light saturation point compared to that of a Florida isolate (Wilson's clone) (67 μmol m−2 s−1 versus 65 μmol m−2 s−1), and light compensation (20–30 μmol m−2 s−11). The upper and lower salinity tolerance of the Texas clone was similar than that of some Florida clones (45 versus 46 and 25 versus 22.5, respectively). In our study, the Texas clone had the same temperature tolerance reported for Florida clones (15–30 °C). While individual clones can vary considerably in maximum growth rates, our results indicate only minor differences exist between the Texas and Florida strains of K. brevis in their temperature and salinity tolerance for growth. While the literature notes lower salinity occurrences of K. brevis in nearby Louisiana, our isolate from the southern Texas coast has the higher salinity requirements typical of K. brevis in the eastern Gulf of Mexico. 相似文献
55.
Clark MJ Chen R Lam HY Karczewski KJ Chen R Euskirchen G Butte AJ Snyder M 《Nature biotechnology》2011,29(10):908-914
Whole exome sequencing by high-throughput sequencing of target-enriched genomic DNA (exome-seq) has become common in basic and translational research as a means of interrogating the interpretable part of the human genome at relatively low cost. We present a comparison of three major commercial exome sequencing platforms from Agilent, Illumina and Nimblegen applied to the same human blood sample. Our results suggest that the Nimblegen platform, which is the only one to use high-density overlapping baits, covers fewer genomic regions than the other platforms but requires the least amount of sequencing to sensitively detect small variants. Agilent and Illumina are able to detect a greater total number of variants with additional sequencing. Illumina captures untranslated regions, which are not targeted by the Nimblegen and Agilent platforms. We also compare exome sequencing and whole genome sequencing (WGS) of the same sample, demonstrating that exome sequencing can detect additional small variants missed by WGS. 相似文献
56.
Contemporary patterns of genetic diversity of cedrela fissilis offer insight into the shaping of seasonal forests in eastern South America 下载免费PDF全文
57.
Almada R Cabrera N Casaretto JA Peña-Cortés H Ruiz-Lara S González Villanueva E 《Plant cell reports》2011,30(10):1959-1968
Grapevine sexual reproduction involves a seasonal separation between inflorescence primordia (flowering induction) and flower
development. We hypothesized that a repression mechanism implicating epigenetic changes could play a role in the seasonal
separation of these two developmental processes in grapevine. Therefore, the expression of five grapevine genes with homology
to the Arabidopsis epigenetic repressor genes FERTILIZATION INDEPENDENT ENDOSPERM (FIE), EMBRYONIC FLOWER 2 (EMF2), CURLY LEAF (CLF), MULTICOPY SUPPRESSOR OF IRA 1 (MSI1) and SWINGER (SWN) was analyzed during the development of buds and vegetative and reproductive organs. During bud development, the putative
grapevine epigenetic repressor genes VvCLF, VvEMF2, VvMSI1, VvSWN and VvFIE are mainly expressed in latent buds at the flowering induction period, but also detected during bud burst and inflorescence/flower
development. The overlapping expression patterns of grapevine PcG-like genes in buds suggest that chromatin remodeling mechanisms could be operating during grapevine bud development for controlling
processes such as seasonal flowering, dormancy and bud burst. Furthermore, the expression of grapevine PcG-like genes was also detected in fruits and vegetative organs, suggesting that epigenetic changes could be at the basis of
the regulation of various proliferation–differentiation cell transitions that occur during grapevine development. 相似文献
58.
Epple R Urbina HD Russo R Liu H Mason D Bursulaya B Tumanut C Li J Harris JL 《Bioorganic & medicinal chemistry letters》2007,17(5):1254-1259
A 6-oxa-1-aza-bicyclo[3.2.1]octan-7-one system inhibits the proteolytic activity of several cysteine proteases belonging to the papain family. In vitro mechanistic studies and in silico calculations suggest that the minimal pi-overlap between the bridgehead nitrogen and the carbonyl leads to a considerable weakening of the urethane system, making it susceptible to nucleophilic attack from the active site thiol group. The resulting covalent adduct is slowly hydrolyzed, releasing the hydroxypiperidine product of the inhibitor. Synthesis and testing of a set of analogs led to variable protease subtype selectivities ranging from micromolar to nanomolar potencies. 相似文献
59.
Ready-to-use DNA extracted with a CTAB method adapted for herbarium specimens and mucilaginous plant tissue 总被引:2,自引:0,他引:2
J. Hugo Cota-Sánchez Kirsten Remarchuk Kumary Ubayasena 《Plant Molecular Biology Reporter》2006,24(2):161-167
This report summarizes major changes in previously published protocols for DNA extraction to improve the quality of DNA extracted
from plants. Here, we highlight the critical modifications in the original protocols. The efficiency of these changes results
in high-quality DNA ready to use in a variety of phytogenetically distant plant families, in particular species with mucopolysaccharides.
The DNA obtained can be used without further purification in various molecular biology assays, including direct sequencing
and AFLP and RAPD (random-amplified polymorphic DNA) analyses. The effectiveness of this method is proven by the amplification
and sequencing of PCR products of up to 1 kb with DNA extracted from herbarium tissue ≥60 years old. This versatility is not
usually found in DNA extraction protocols. In addition, this method is quick, adaptable to standard laboratories, and most
important, safer and more cost-effective. 相似文献
60.
The effects of l-DOPA on root growth, lignification and enzyme activity in soybean seedlings 总被引:1,自引:0,他引:1
Anderson Ricardo Soares Rita de Cássia Siqueira-Soares Victor Hugo Salvador Maria de Lourdes Lucio Ferrarese Osvaldo Ferrarese-Filho 《Acta Physiologiae Plantarum》2012,34(5):1811-1817
In the present study, we investigated the effects of l-DOPA (l-3,4-dihydroxyphenylalanine), an allelochemical exuded from the velvetbean (Mucuna pruriens L DC. var. utilis), on the growth and cell viability of soybean (Glycine max L. Merrill) roots. We analyzed the effects of l-DOPA on phenylalanine ammonia lyase (PAL), cinnamyl-alcohol dehydrogenase (CAD) and cell wall-bound peroxidase (POD) activities as well as its effects on phenylalanine, tyrosine and lignin contents in the roots. 3-day-old seedlings were cultivated in half-strength Hoagland nutrient solution (pH 6.0), with or without 0.5?mM l-DOPA, in a growth chamber at 25?°C for 6, 12, 18 or 24?h with a day/night regime of 1:1, and a photon flux density of 280???mol?m?2 s?1. In general, the length, fresh weight and dry weight of the roots decreased followed by a significant loss of cell viability. Phenylalanine, tyrosine and lignin contents as well as PAL, CAD and cell wall-bound POD activities increased after l-DOPA treatment. These results reinforce the susceptibility of soybean to l-DOPA, which increases the enzyme activity in the phenylpropanoid pathway and, therefore, provides precursors for the polymerization of lignin. In brief, these findings suggest that the inhibition of soybean root growth induced by exogenously applied l-DOPA may be due to excessive production of lignin in the cell wall. 相似文献