The cellular prion protein PrPC is encoded by the Prnp gene. This protein is expressed in the central nervous system (CNS) and serves as a precursor to the misfolded PrPSc isoform in prion diseases. The prototype prion disease is scrapie in sheep, and whereas Prnp exhibits common missense polymorphisms for V136A, R154H and Q171R in ovine populations, genetic variation in mouse Prnp is limited. Recently the CNS glycoprotein Shadoo (Sho) has been shown to resemble PrPC both in a central hydrophobic domain and in activity in a toxicity assay performed in cerebellar neurons. Sho protein levels are reduced in prion infections in rodents. Prompted by these properties of the Sho protein we investigated the extent of natural variation in SPRN.
Principal Findings
Paralleling the case for ovine versus human and murine PRNP, we failed to detect significant coding polymorphisms that alter the mature Sho protein in a sample of neurologically normal humans, or in diverse strains of mice. However, ovine SPRN exhibited 4 missense mutations and expansion/contraction in a series of 5 tandem Ala/Gly-containing repeats R1-R5 encoding Sho''s hydrophobic domain. A Val71Ala polymorphism and polymorphic expansion of wt 67(Ala)3Gly70 to 67(Ala)5Gly72 reached frequencies of 20%, with other alleles including Δ67–70 and a 67(Ala)6Gly73 expansion. Sheep V71, A71, Δ67–70 and 67(Ala)6Gly73 SPRN alleles encoded proteins with similar stability and posttranslational processing in transfected neuroblastoma cells.
Significance
Frequent coding polymorphisms are a hallmark of the sheep PRNP gene and our data indicate a similar situation applies to ovine SPRN. Whether a common selection pressure balances diversity at both loci remains to be established. 相似文献
The immune responses of individuals exposed to Leishmania major were evaluated and compared with those of non-exposed volunteers. Forty-one patients with active lesion(s), 43 healed individuals, 15 vaccinees 1 month or 1 year post vaccination, and 15 non-exposed volunteers were studied. Leishmanin skin test (LST) response, proliferative response of lymphocyte (PRL) to L. major antigen, IFN-gamma and IL-4 production, and percentage of L. major-specific CD4+, CD8+ and CD16+/CD56+ cells in peripheral blood mononuclear cells were assessed. Data showed positive LST (>5 mm) in 92% of patients, 98% of healed, and 80% or 43% of vaccinees 1 month and 1 year post vaccination, respectively. Positive PRL (SI>2.5) was displayed in 90%, 84%, 46% and 7% of patients, healed, vaccinated (post 1 year) and non-exposed donors, respectively. The mean +/-S.E. of IFN-gamma was 924 +/- 149, 1,278 +/- 185, 470 +/- 282 or 258 +/- 82 pg/ml in patients, healed cases and vaccinees after 1 month or 1 year, respectively. Positive IFN-gamma responders (>300 pg/ml) were shown in 72% of patients, 81% of healed cases, 31% or 39% of vaccinees and 0% of non-exposed donors. A reduced percentage of CD4+ T-cells and an increased percentage of NK cells were found in exposed individuals compared to non-exposed donors. The data indicated that exposure to L. major modulates the proportion of CD4+ T cells and increases NK cells percentage. However, the cellular immune responses including induction of LST, and IFN-gamma production are increased in exposed individuals. 相似文献
The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods
were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have
the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales),
Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation
index (Igeo) was used to determine the degree of contamination in the sediments. Igeo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations
in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable
sediment) for some metals were higher than 1. 相似文献
Antibody titers to several heat shock proteins (anti-Hsps) have been reported to be associated with the severity and progression of cardiovascular disease. However, there are little data regarding anti-Hsp27 titers in patients with coronary artery disease (CAD). A total of 400 patients with suspected CAD were recruited. Based on the results of coronary angiography, these patients were classified into CAD+ (n = 300) and CAD− (n = 100) groups defined as patients with ≥50% and <50% stenosis of any major coronary artery, respectively. Eighty-three healthy subjects were also recruited as the control group. Serum anti-Hsp27 IgG titers were measured using an in-house enzyme-linked immunosorbent assay. CAD+ patients had significantly higher anti-Hsp27 titers compared with both CAD− and control groups. Anti-Hsp27 titers were also higher in the CAD− group compared with the control group. With regard to the number of affected vessels in the CAD+ group, patients with three-vessel disease had higher anti-Hsp27 titers compared with both two-vessel disease (2VD) and one-vessel disease (1VD) subgroups. However, there was no significant difference between 1VD and 2VD subgroups. In multiple linear regression analysis, the number of narrowed vessels and smoking were significant independent determinants of serum anti-Hsp27 titers. The present findings indicate that serum anti-Hsp27 titers may be associated with the presence and severity of coronary artery disease. 相似文献
A combination of vacuum liquid chromatography (VLC) and preparative thin layer chromatography (PTLC) of the dichloromethane extract of the aerial parts of the Iranian plant Pimpinella aurea afforded two phenylpropanoids, erythro-1'-(4-methoxyphenyl)-propan-1',2'-diol (1) and erythro-1'-[4-(sec-butyl)-phenyl]-propan-1',2'-diol (2), the latter being a natural product. The structures of these compounds were determined by spectroscopic means. The antioxidant properties of these compounds were assessed by the DPPH assay. The GC-MS analysis of the essential oils of P. aurea provided a chemical profile that was significantly different from the previously published reports. 相似文献
Prangos ferulacea is one of the widely used, nutritional and popular fodders in livestock industry. This species is also considered as an important option in rangeland restoration and management. In this study, the comparative phytotoxic activity of aqueous and hydroalcoholic extracts obtained from different organs (flower, shoot and leaf) of P. ferulacea on proline content, seed germination and seedling growth of Trifolium resupinatum has been investigated. According to the results, the hydroalcoholic extract of P. ferulaceae flower possesses the highest total phenolic and flavonoid content and the uppermost phytotoxic effect on T. resupinatum. The extracts significantly decreased seed germination and seedling growth of T. resupinatum and increased the proline content. Our findings indicate that hydroalcoholic extract induced a stronger oxidative stress in T. resupinatum. Finally, based on the results, aqueous allelochemicals that originated from P. ferulacea played a significant role in the successful propagation and development of T. resupinatum in rehabilitated pastures. According to our results, the phytotoxicity effect of the hydroalcoholic extract was significantly higher than that of the aqueous extract. Since in nature, the allelopathic interaction between plants is closer to the aqueous method, primary evaluations of rangeland restoration using this method is suggested. 相似文献
Detecting a QTL is only the first step in genetic improvement programs. When a QTL with desirable characteristics is found, e.g. in a wild or unimproved population, it may be interesting to introgress the detected QTL into the commercial population. One approach to shorten the time needed for introgression is to combine both QTL identification and introgression, into a single step. This combines the strengths of fine mapping and backcrossing and paves the way for introgression of desirable but unknown QTL into recipient animal and plant lines.
Methods
The method consisting in combining QTL mapping and gene introgression has been extended from inbred to outbred populations in which QTL allele frequencies vary both in recipient and donor lines in different scenarios and for which polygenic effects are included in order to model background genes. The effectiveness of the combined QTL detection and introgression procedure was evaluated by simulation through four backcross generations.
Results
The allele substitution effect is underestimated when the favourable QTL allele is not fixed in the donor line. This underestimation is proportional to the frequency differences of the favourable QTL allele between the lines. In most scenarios, the estimates of the QTL location are unbiased and accurate. The retained donor chromosome segment and linkage drag are similar to expected values from other published studies.
Conclusions
In general, our results show that it is possible to combine QTL detection and introgression even in outbred species. Separating QTL mapping and introgression processes is often thought to be longer and more costly. However, using a combined process saves at least one generation. With respect to the linkage drag and obligatory drag, the results of the combined detection and introgression scheme are very similar to those of traditional introgression schemes. 相似文献
In recent years, the application of arbuscular mycorrhizal fungi (AMF) has been considered to be an important strategy for improving crop yield and quality. In the present study, a factorial experiment based on a complete randomized design with two factors was performed to investigate the effect of AMF and water stress on the essential oil (EO) composition, antioxidant activity, and physiological and morphological characteristics of rose-scented geranium (Pelargonium graveolens L.). The factors included AMF inoculation (Rhizophagus intraradices, Funneliformis mosseae, and a mixture of both species) and irrigation levels [well-watered (WW), moderate drought stress (MDS), and severe drought stress (SDS)]. The main EO constituents were citronellol (31–37%) and geraniol (9–14%) in all treatments. Under water-stress conditions, some constituents increased, such as geraniol and geranyl formate, whereas others decreased, such as linalool, menthone and rose oxide. Overall, the highest amount of citronellol (37.3%) and geraniol (14.8%) was obtained in the plants inoculated with F. mosseae and R. intraradices under WW and MDS conditions, respectively. Antioxidant activity, total flavonoids, and phenolics were increased because of AMF inoculation, whereas a different trend was observed for the phenolic and flavonoid contents under water-stress conditions. Furthermore, water deficit elevated the amount of soluble carbohydrates as well as the proline content, whereas the amount of proline was lower in inoculated plants than in non-inoculated ones. All the growth parameters were improved in the AMF-inoculated plants compared to non-inoculated ones under different irrigation regimes. Drought conditions decreased the photosynthetic pigments and efficiency, whereas AMF plants ameliorated the adverse effect of drought conditions. In general, mycorrhizal inoculation resulted in an improvement in the growth parameters as well as the phytochemical and physiological characteristics of rose-scented geranium.
After determination of sorption isotherms of grape seeds using gravimetric method, five models with temperature effect were used to fit water sorption isotherms of grape seeds to investigate temperature effect on sorption isotherms and its thermodynamic characteristics. Halsey model had minimum mean relative percentage error (Me) and all other models used were good in fitting experimental data (with Me of less than 10 %). Differential parameters such as net isosteric heat, isosteric heat, differential entropy and integral function such as equilibrium heat, net equilibrium heat, integral entropy and surface potential have been calculated. The net isosteric heat, isosteric heat and differential entropy decreased with moisture content. The net equilibrium enthalpy, equilibrium enthalpy and integral entropy decreased with moisture content. The surface potential at four temperatures (35, 45, 55 and 65 °C) was estimated, and low temperature effect was reported. 相似文献
Due to their important biomedical applications, functional human embryonic stem cell-derived hepatocyte-like cells (hESC-HLCs) are an attractive topic in the field of stem cell differentiation. Here, we have initially differentiated hESCs into functional hepatic endoderm (HE) and continued the differentiation by replating them onto galactosylated collagen (GC) and collagen matrices. The differentiation of hESC-HE cells into HLCs on GC substrate showed significant up-regulation of hepatic-specific genes such as ALB, HNF4α, CYP3A4, G6P, and ASGR1. There was more albumin secretion and urea synthesis, as well as more cytochrome p450 activity, in differentiated HLCs on GC compared to the collagen-coated substrate. These results suggested that GC substrate has the potential to be used for in vitro maturation of hESC-HLCs. 相似文献