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71.
Becca Asquith Angelina J Mosley Adrian Heaps Yuetsu Tanaka Graham P Taylor Angela R McLean Charles RM Bangham 《Retrovirology》2005,2(1):1-9
Background
Cellular infection with human immunodeficiency virus (HIV) both in vitro and in vivo requires a member of the chemokine receptor family to act as a co-receptor for viral entry. However, it is presently unclear to what extent the interaction of HIV proteins with chemokine receptors generates intracellular signals that are important for productive infection.Results
In this study we have used a recently described family of chemokine inhibitors, termed BSCIs, which specifically block chemokine-induced chemotaxis without affecting chemokine ligands binding to their receptors. The BSCI termed Peptide 3 strongly inhibited CCR5 mediated HIV infection of THP-1 cells (83 ± 7% inhibition assayed by immunofluoresence staining), but had no effect on gp120 binding to CCR5. Peptide 3 did not affect CXCR4-dependent infection of Jurkat T cells.Conclusion
These observations suggest that, in some cases, intracellular signals generated by the chemokine coreceptor may be required for a productive HIV infection. 相似文献72.
W. A. Van Giessen C. Mollema K. D. Elsey 《Entomologia Experimentalis et Applicata》1995,76(3):271-286
SARAH (Software for theAssessment of antibioticResistance toAleyrodidae inHost plants) is a deterministic simulation model of whitefly population growth based on whitefly life-history components determined
on individual plants. The life-history components recorded were oviposition rate, adult survival, pre-adult survival, developmental
period, and sex ratio. The simulation model serves as a tool to combine these components and to obtain a single criterion
for (antibiotic) resistance. The criterion used was the decrease in simulated intrinsic population growth rate, r
s
, relative the r
s
value determined on a susceptible control genotype. This model-based evaluation method was tested using the greenhouse whitefly,Trialeurodes vaporariorum Westwood, on tomato and the sweetpotato whitefly,Bemisia tabaci Gennadius, on tomato, eggplant, collard, and pepper.
To study its consistency over time, the evaluation method was repeated six times forT. vaporariorum on a susceptible and a resistant tomato cultivar. Simulated intrinsic population growth rate was more consistent in indicating
resistance than any of the individual life-history components. Of tenL. hirsutum accessions tested for resistance toT. vaporariorum, three exhibited r
s
values that were significantly lower than those for the susceptible control. In addition, on these tenL. hirsutum accessions, a significant positive correlation was observed between r
s
and sex ratio (# females/# males).
Four host plant species (tomato, collard, eggplant, and pepper) were evaluated for resistance toB. tabaci. All life-history components and r
s
values varied among host species, while a negative r
s
value was observed forB. tabaci on pepper.
A high correlation was found between results from a sensitivity analysis of SARAH and results from a sensitivity analysis
of a validated whitefly population simulation model by Yanoet al. (1989a). Significant correlations were found for the relationships between oviposition rate, adult survival, or pre-adult
survival and r
s
, indicating that none of these life-history components can be omitted from the test procedure. This model-based evaluation
method offers a standardized way to quantify levels of antibiotic resistance to whiteflies and will enhance efficiency in
breeding programs. 相似文献
73.
74.
Aileen?G?RowanEmail author Koichiro?Suemori Hiroshi?Fujiwara Masaki?Yasukawa Yuetsu?Tanaka Graham?P?Taylor Charles?RM?Bangham 《Retrovirology》2014,11(1):116
Background
Immunogenetic evidence indicates that cytotoxic T lymphocytes (CTLs) specific for the weak CTL antigen HBZ limit HTLV-1 proviral load in vivo, whereas there is no clear relationship between the proviral load and the frequency of CTLs specific for the immunodominant antigen Tax. In vivo, circulating HTLV-1-infected cells express HBZ mRNA in contrast, Tax expression is typically low or undetectable. To elucidate the virus-suppressing potential of CTLs targeting HBZ, we compared the ability of HBZ- and Tax-specific CTLs to lyse naturally-infected cells, by co-incubating HBZ- and Tax-specific CTL clones with primary CD4+ T cells from HLA-matched HTLV-1-infected donors. We quantified lysis of infected cells, and tested whether specific virus-induced host cell surface molecules determine the susceptibility of infected cells to CTL-mediated lysis.Results
Primary infected cells upregulated HLA-A*02, ICAM-1, Fas and TRAIL-R1/2 in concert with Tax expression, forming efficient targets for both HTLV-1-specific CTLs and CTLs specific for an unrelated virus. We detected expression of HBZ mRNA (spliced isoform) in both Tax-expressing and non-expressing infected cells, and the HBZ26–34 epitope was processed and presented by cells transfected with an HBZ expression plasmid. However, when coincubated with primary cells, a high-avidity HBZ-specific CTL clone killed significantly fewer infected cells than were killed by a Tax-specific CTL clone. Finally, incubation with Tax- or HBZ-specific CTLs resulted in a significant decrease in the frequency of cells expressing high levels of HLA-A*02.Conclusions
HTLV-1 gene expression in primary CD4+ T cells non-specifically increases susceptibility to CTL lysis. Despite the presence of HBZ spliced-isoform mRNA, HBZ epitope presentation by primary cells is significantly less efficient than that of Tax.75.
76.
77.
Merchant ME Roche C Elsey RM Prudhomme J 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2003,136(3):505-513
Treatment of alligator (Alligator mississippiensis) and human serum samples with Escherichia coli resulted in a time- and concentration-dependent inhibition of bacterial proliferation. When inoculated with E. coli, alligator serum exhibited 10-fold lower bacterial survival rates after 1 h than human serum. In addition, the antibacterial spectrum of alligator serum was shown to be much broader than that of human serum, with growth inhibition occurring in 100% of bacterial strains tested (compared to only 35% for human serum). Additional results showed that the antimicrobial activities of alligator serum could be completely inhibited by preincubation with proteases, indicating the proteinaceous nature of the antimicrobial activities. Furthermore, incubation of alligator serum at 56 degrees C for 30 min (classical human serum complement inactivation conditions) obliterated all antimicrobial properties of the alligator serum. The antibacterial activities occurred relatively quickly in vitro, with significant activity occurring within 5 min of inoculation with E. coli and maximal activity at 20 min. Also, the antimicrobial activity exhibited temperature dependence, with a substantial decrease in activity below 15 degrees C. These data suggest that the antimicrobial properties of alligator serum may be due to an active serum complement system. 相似文献
78.
Microsatellite DNA analyses support an east-west phylogeographic split of American alligator populations 总被引:3,自引:0,他引:3
Davis LM Glenn TC Strickland DC Guillette LJ Elsey RM Rhodes WE Dessauer HC Sawyer RH 《The Journal of experimental zoology》2002,294(4):352-372
We examined the population genetic structure of American alligators (Alligator mississippiensis) sampled from 12 localities across the southeastern United States. The primary goal of this study was to determine the extent of population differentiation among alligators from four Florida lakes using eight microsatellite loci and compare the results to additional sites located at varying distances from them. Analyses of population structure revealed little differentiation (F(ST)=0.039; Rho=0.012) among the four Florida lakes, Apopka, Griffin, Orange and Woodruff, which are all located in the St. John&'s River watershed in north-central Florida. Further, there was little differentiation among these samples and samples collected from the Everglades National Park (F(ST)=0.044; Rho=0.009) and south Georgia (F(ST)=0.045; Rho=0.032). Therefore, these six samples were pooled together as a "FL/sGA group." Similarly, samples collected in the western extent of the range, Anahuac National Wildlife Refuge in Texas and Salvador Wildlife Management Area, Marsh Island Wildlife Refuge and Rockefeller Wildlife Refuge in Louisiana, also lacked population structure (F(ST)=0.024; R(ST)=0.040). These four populations were pooled into the "TX/LA group." Comparisons of these two groups with samples taken from the Santee Coastal Reserve in South Carolina and Mobile, Alabama yielded three to four times more differentiation among groups (F(ST)=0.131; Rho=0.187). These and other analyses support the hypothesis of an east-west phylogeographic split in American alligator populations and are consistent with studies of many freshwater fish and aquatic and terrestrial turtles distributed throughout this same geographic region. 相似文献
79.
Kent D. Elsey 《Journal of nematology》1989,21(3):416-418
The development and survival of egg, juvenile (parasitic), preovipositing, and ovipositing stages of the parasitic mermithid Filipjevimermis leipsandra were determined at eight temperatures. Infection of the host, Diabrotica balteata, peaked at 30 C and fell off sharply at warmer or cooler temperatures. No development, oviposition, or infection occurred at < 20 C. Fecundity was highest at 25 C, and 50% of the eggs were laid in the first 4-7 days of oviposition. 相似文献
80.
A molecular and evolutionary study of the beta-globin gene family of the Australian marsupial Sminthopsis crassicaudata 总被引:1,自引:0,他引:1
Cooper SJ; Murphy R; Dolman G; Hussey D; Hope RM 《Molecular biology and evolution》1996,13(7):1012-1022
Beta-globin gene families in eutherians (placental mammals) consist of a
set of four or more developmentally regulated genes which are closely
linked and, in general, arranged in the order 5'-embryonic/fetal genes-
adult genes-3'. This cluster of genes is proposed to have arisen by tandem
duplication of ancestral beta-globin genes, with the first duplication
occurring 200 to 155 MYBP just prior to a period in mammalian evolution
when eutherians and marsupials diverged from a common ancestor. In this
paper we trace the evolutionary history of the beta-globin gene family back
to the origins of these mammals by molecular characterization of the
beta-globin gene family of the Australian marsupial Sminthopsis
crassicaudata. Using Southern and restriction analysis of total genomic DNA
and bacteriophage clones of beta-like globin genes, we provide evidence
that just two functional beta-like globin genes exist in this marsupial,
including one embryonic- expressed gene (S.c-epsilon) and one
adult-expressed gene (S.c-beta), linked in the order 5'-epsilon-beta-3'.
The entire DNA sequence of the adult beta-globin gene is reported and shown
to be orthologous to the adult beta-globin genes of the North American
marsupial Didelphis virginiana and eutherian mammals. These results,
together with results from a phylogenetic analysis of mammalian beta-like
globin genes, confirm the hypothesis that a two-gene cluster, containing an
embryonic- and an adult-expressed beta-like globin gene, existed in the
most recent common ancester of marsupials and eutherians. Northern analysis
of total RNA isolated from embryos and neonatals indicates that a switch
from embryonic to adult gene expression occurs at the time of birth,
coinciding with the transfer of the marsupial from a uterus to a pouch
environment.
相似文献