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71.
van Gils MJ Bunnik EM Boeser-Nunnink BD Burger JA Terlouw-Klein M Verwer N Schuitemaker H 《Journal of virology》2011,85(14):6986-6995
Human immunodeficiency virus type 1 (HIV-1) has the ability to adapt to the host environment by escaping from host immune responses. We previously observed that escape from humoral immunity, both at the individual and at a population level, coincided with longer variable loops and an increased number of potential N-linked glycosylation sites (PNGS) in the viral envelope glycoprotein (Env) and, in particular, in variable regions 1 and 2 (V1V2). Here, we provide several lines of evidence for the role of V1V2 in the resistance of HIV-1 to neutralizing antibodies. First, we determined that the increasing neutralization resistance of a reference panel of tier-categorized neutralization-sensitive and -resistant HIV-1 variants coincided with a longer V1V2 loop containing more PNGS. Second, an exchange of the different variable regions of Env from a neutralization-sensitive HIV-1 variant into a neutralization-resistant escape variant from the same individual revealed that the V1V2 loop is a strong determinant for sensitivity to autologous-serum neutralization. Third, exchange of the V1V2 loop of neutralization-sensitive HIV-1 variants from historical seroconverters with the V1V2 loop of neutralization-resistant HIV-1 variants from contemporary seroconverters decreased the neutralization sensitivity to CD4-binding site-directed antibodies. Overall, we demonstrate that an increase in the length of the V1V2 loop and/or the number of PNGS in that same region of the HIV-1 envelope glycoprotein is directly involved in the protection of HIV-1 against HIV-specific neutralizing antibodies, possibly by shielding underlying epitopes in the envelope glycoprotein from antibody recognition. 相似文献
72.
Microsatellites, or short tandem repeats (STR's), are popular tools to discriminate between microbial isolates. Here, we report on the robustness of a microsatellite panel for discrimination of Aspergillus fumigatus isolates. Two major PCR artefacts (stutter peaks and minus-A peaks) can complicate correct interpretation of STR data. We investigated the effect of alterations to the various components of the PCR amplification mixtures on these PCR artefacts and on the reproducibility of this assay. Some extreme conditions led to a loss of signal, but, under all conditions where a signal was obtained, identical typing results were produced. Furthermore, pitfalls with the exchange of results between labs are discussed. These pitfalls are primarily associated with sizing of the obtained PCR fragments. 相似文献
73.
74.
Hanneke van Leur Ciska E. Raaijmakers & Nicole M. van Dam 《Entomologia Experimentalis et Applicata》2008,128(2):312-322
The cabbage root fly, Delia radicum L. (Diptera: Anthomyiidae), has a life cycle with spatially separated components: adults live and oviposit above ground, whereas larvae feed and pupate below ground. Oviposition choice is affected by shoot glucosinolates. However, little is known about below‐ground plant defence against D. radicum. Here, we investigate the effect of glucosinolates on oviposition preference and performance of D. radicum, using two naturally occurring heritable chemotypes of Barbarea vulgaris R. Br. (Brassicaceae) with different glucosinolate profiles: BAR‐type plants (the most common and genetically dominant glucosinolate profile, dominated by glucobarbarin) and NAS‐type plants (the recessive phenotype, dominated by gluconasturtiin). Performance was studied by applying 10 neonate D. radicum larvae per plant and measuring pupal biomass after 18 days. There was no difference in retrieval, but pupae had a higher biomass after development on BAR‐type plants. On average, BAR‐type plants received 1.8 times more eggs than NAS types, but this difference was not statistically significant. In a separate experiment, we compared the physiological response of both chemotypes to D. radicum feeding. Infestation reduced root and shoot biomass, root sugar and amino acid levels, and shoot sugar levels. Except for shoot sugar levels, these responses did not differ between the two chemotypes. Shoot or root glucosinolate profiles did not change on infestation. As glucosinolate profiles were the only consistent difference between the chemotypes, it is likely that this difference caused the reduced biomass of D. radicum pupae on NAS‐type plants. In an experimental garden, plants were heavily infested by root flies, but we found no differences in the percentage of fallen‐over flower stalks between the chemotypes. Overall, we found more pupae in the soil near BAR‐type plants, but this was not statistically significant. The results of the performance experiment suggest that BAR‐type plants may be more suitable hosts than NAS‐type plants. 相似文献
75.
In natural populations of Barbarea vulgaris we found two distinctly different glucosinolate profiles. The most common glucosinolate profile is dominated (94%) by the hydroxylated form, (S)-2-hydroxy-2-phenylethyl-glucosinolate (glucobarbarin, BAR-type), whereas in the other type 2-phenylethyl-glucosinolate (gluconasturtiin, NAS-type) was most prominent (82%). NAS-type plants have a 108-fold increase of gluconasturtiin concentration in rosette leaves compared to BAR-type plants. The glucosinolate composition of both chemotypes is consistent throughout all plant organs and after induction with jasmonic acid. Although the glucosinolate profile of the roots has a more diverse composition than other plant organs, it still matches the chemotype. In 12 natural populations that we sampled in Germany, Belgium, France and Switzerland solely BAR-type plants were found. However, eight out of the 15 Dutch populations that were sampled contained 2-22% NAS-type plants. Controlled crosses showed that the chemotype was heritable and determined by a single gene with two alleles. The allele coding for the BAR-type was dominant and the allele for the NAS-type was recessive. The different glucosinolate profiles will yield different hydrolysis products upon damage, and therefore we expect them to differentially affect the multitrophic interactions associated with B. vulgaris in their natural environment. 相似文献
76.
van Berloo Ralph Aalbers Hanneke Werkman Arjen Niks Rients E. 《Molecular breeding : new strategies in plant improvement》2001,8(3):187-195
Near-isogenic lines (NILs) differing with regard to disease QTLs provide valuable material for a more detailed study into the genetic basis of quantitative resistance. Previously obtained information on QTLs that show an effect on leaf rust (Puccinia hordei) in barley was used in a marker-assisted backcross programme. The genome origin in backcross plants was controlled through AFLP marker analysis and graphical genotyping. Plants obtained after the third generation of backcrossing sufficiently resembled the recurrent parent. For one QTL, BC3S1 plants were evaluated in a disease test and genotyped. NILs containing the desired QTL in homozygous condition in a recipient background were finally obtained. A disease test and verification of the marker genotype confirmed the identity of the NILs. Simultaneous with the backcross programme a simulation study on efficiency of marker-assisted backcrossing was performed. 相似文献
77.
Hanneke J. M. Meijer Marco Pavia Joan Madurell-Malapeira David M. Alba 《Historical Biology》2017,29(6):822-832
The European fossil record of eagle owls, genus Bubo Duméril 1806, is thought to extend back into the Miocene, but records of Bubo before the Middle Pleistocene are scarce and mainly constituted by non-diagnostic or fragmentary specimens. Apart from a number of fossil species of Bubo of uncertain validity, i.e. Bubo? florianae Kretzoi 1957, Bubo lignitum Giebel 1860, and Bubo perpastus (Ballman 1976), most fossil Bubo material is unassigned to species or assigned to the extant Bubo bubo (Linnaeus 1758) on the basis of size, especially for Early Pleistocene records. Given the ambiguity about the validity of the earliest records, here we revise the pre-Middle Pleistocene fossil record of Bubo in Europe. Our results indicate that, in Europe, Bubo is first recorded in the Late Pliocene/Early Pleistocene of Italy. By the Early Pleistocene, three taxa can be distinguished: Bubo ibericus sp. nov. from Cal Guardiola (Spain), Bubo sp. nov. indet. from Soave Cava Sud (Italy) and Bubo sp. from various sites across Europe. By the Middle Pleistocene, Eurasian environments experienced a substantial increase in severity and duration of glacial periods which might have led to the replacement of extinct species of Bubo by the recent B. bubo and Bubo scandiacus. 相似文献
78.
Laetitia Chauve Francesca Hodge Sharlene Murdoch Fatemeh Masoudzadeh Harry-Jack Mann Andrea F. Lopez-Clavijo Hanneke Okkenhaug Greg West Bebiana C. Sousa Anne Segonds-Pichon Cheryl Li Steven W. Wingett Hermine Kienberger Karin Kleigrewe Mario de Bono Michael J. O. Wakelam Olivia Casanueva 《PLoS biology》2021,19(11)
To survive elevated temperatures, ectotherms adjust the fluidity of membranes by fine-tuning lipid desaturation levels in a process previously described to be cell autonomous. We have discovered that, in Caenorhabditis elegans, neuronal heat shock factor 1 (HSF-1), the conserved master regulator of the heat shock response (HSR), causes extensive fat remodeling in peripheral tissues. These changes include a decrease in fat desaturase and acid lipase expression in the intestine and a global shift in the saturation levels of plasma membrane’s phospholipids. The observed remodeling of plasma membrane is in line with ectothermic adaptive responses and gives worms a cumulative advantage to warm temperatures. We have determined that at least 6 TAX-2/TAX-4 cyclic guanosine monophosphate (cGMP) gated channel expressing sensory neurons, and transforming growth factor ß (TGF-β)/bone morphogenetic protein (BMP) are required for signaling across tissues to modulate fat desaturation. We also find neuronal hsf-1 is not only sufficient but also partially necessary to control the fat remodeling response and for survival at warm temperatures. This is the first study to show that a thermostat-based mechanism can cell nonautonomously coordinate membrane saturation and composition across tissues in a multicellular animal.In response to heat, ectotherms exhibit an adaptive response characterized by changes in membrane fluidity. This study in the nematode Caenorhabditis elegans shows that neuronal HSF-1 is critical for this remodeling, suggesting a neuronal thermostat-based mechanism that can non-cell-autonomously coordinate the animal’s response to heat. 相似文献
79.
80.
Hanneke Joosten Sipke T. Visser Marlise E. van Eersel Ron T. Gansevoort Henk J. G. Bilo Joris P. Slaets Gerbrand J. Izaks 《PloS one》2014,9(12)
We aimed to evaluate the association between statin use and cognitive function. Cognitive function was measured with the Ruff Figural Fluency Test (RFFT; worst score, 0; best score, 175 points) and the Visual Association Test (VAT; low performance, 0–10; high performance, 11–12 points) in an observational study that included 4,095 community-dwelling participants aged 35–82 years. Data on statin use were obtained from a computerized pharmacy database. Analysis were done for the total cohort and subsamples matched on cardiovascular risk (N = 1232) or propensity score for statin use (N = 3609). We found that a total of 904 participants (10%) used a statin. Statin users were older than non-users: mean age (SD) 61 (10) vs. 52 (11) years (p<0.001). The median duration of statin use was 3.8 (interquartile range, 1.6–4.5) years. Unadjusted, statin users had worse cognitive performance than non-users. The mean RFFT score (SD) in statin users and non-users was 58 (23) and 72 (26) points, respectively (p<0.001). VAT performance was high in 261 (29%) statin users and 1351 (43%) non-users (p<0.001). However, multiple regression analysis did not show a significant association of RFFT score with statin use (B, −0.82; 95%CI, −2.77 to 1.14; p = 0.41) nor with statin solubility, statin dose or duration of statin use. Statin users with high doses or long-term use had similar cognitive performance as non-users. This was found in persons with low as well as high cardiovascular risk, and in younger as well as older subjects. Also, the mean RFFT score per quintile of propensity score for statin use was comparable for statin users and non-users. Similar results were found for the VAT score as outcome measure. In conclusion, statin use was not associated with cognitive function. This was independent of statin dose or duration of statin use. 相似文献