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71.
To achieve higher level expression of Interferon α2b (IFN-α2b) in methylotrophic yeast (Pichia pastoris), a cDNA fragment coding for the mature IFN-α2b was designed and synthesized based on the synonymous codon bias of P. pastoris and optimized G+C content. The synthetic IFN-α2b was inserted into the secreted expression vector pPICZαA, and then integrated
into P. pastoris GS115 genome by electroporation. Multi-copy integrants in the Mut+ recombinant P. pastoris strain were screened by high concentrations of Zeocin. 120 hours culturing allowed expression of the IFN-α2b transformant
up to 810 mg/L as detected by SDS-PAGE and quantitative methods. In addition, Western blot analysis showed that the recombinant
proteins had immunogenicity. The significant antiviral activity of the recombinant IFN-α2b protein was verified by WISH/ VSV
system, which was 3.3×105 IU/mL.
Foundation items: The National ‘973’ Basic Research Program (2002CB111302); The National Natural Science Foundation of China
(30370807) 相似文献
72.
Defining the coast and sentinel ecosystems for coastal observations of global change 总被引:1,自引:0,他引:1
The detection, attribution and prediction of global and large scale regional change are goals for the Global Observing Systems
of the United Nations. Coastal areas are particularly sensitive to global change, but there is a variety of limitations to
universal coverage of observations. The coastal module of the Global Terrestrial Observing System (C-GTOS) considers sentinel
ecosystems to address these goals for the terrestrial, wetland and freshwater ecosystems of the coast. Sentinel ecosystems
for observing systems are a limited number of well understood systems that have substantial datasets and are observed in a
sustained fashion, forming an early warning and core system for broader regional and global change. A necessary step in the
development of C-GTOS is the examination of current definitions of coastal areas by anticipated users and information providers,
and identification of potential coastal networks and sites. We applied the sentinel system framework to the selection of C-GTOS
observation sites from several international programs using various global delineations of coastal areas. Delineations were
based on the most common definitions of the coast adopted by potential C-GTOS users and information providers, and included
mapped areas of various distance from the coastline, coastal areas of low elevation, and a seaward boundary matching the Economic
Exclusive Zone (EEZ). Decreases in the number of sites within each international program occurred with each definition marking
area closer to the coastline. The Ramsar Convention on Wetlands demonstrates the greatest percentage of coastal sites by any
definition. The process of choosing specific sentinel sites for C-GTOS continues from this initial screening, and is the next
step towards the development of an in situ site network supporting the observation of global and large scale change.
An erratum to this article is available at . 相似文献
73.
Genetic diversity in spring bread wheat (T.␣aestivum L.) was studied in a total of 69 accessions. For this purpose, 52 microsatellite (SSR) markers were used and a total of 406
alleles were detected, of which 182 (44.8%) occurred at a frequency of <5% (rare alleles). The number of alleles per locus
ranged from 2 to 14 with an average of 7.81. The largest number of alleles per locus occurred in the B genome (8.65) as␣compared
to the A (8.43) and D (5.93) genomes, respectively. The polymorphism index content (PIC) value varied from 0.24 to 0.89 with
an average of 0.68. The highest PIC for all accessions was found in the B␣genome (0.71) as compared to the A (0.68) and D␣genomes
(0.63). Genetic distance-based method (standard UPGMA clustering) and a model-based method (structure analysis) were used for cluster analysis. The two methods led to analogical results. Analysis of molecular variance (AMOVA)
showed that 80.6% of the total variation could be explained by the variance within the geographical groups. In comparison
to the diversity detected for all accessions (H
e
= 0.68), genetic diversity among European spring bread wheats was H
e
= 0.65. A comparatively higher diversity was observed between wheat varieties from Southern European countries (Austria/Switzerland,
Portugal/Spain) corresponding to those from other regions. 相似文献
74.
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignant disease with poor long-term survival rates. Major reason
for poor disease outcome is the profound intrinsic resistance of PDAC cells to currently available treatment regimens. We
recently found that a great majority of PDAC tumors and tumor cell lines express high basal level of tissue transglutaminase
(TG2), a multifunctional protein implicated in apoptosis, cell attachment, cell survival, and cell motility functions. Based
on these observations, we hypothesized that activation of endogenous TG2 can induce spontaneous apoptosis in PDAC cells. The
results obtained suggested that activation of endogenous TG2 by calcium ionophore A23187 induced rapid and spontaneous apoptosis
in PDAC cells. TG2-induced apoptosis was associated with release of apoptosis-inducing factor (AIF). The release of AIF from
mitochondria led to its translocation to the nucleus and subsequent apoptosis of PDAC cells in caspase-independent manner.
In conclusion, our results provide first evidence that TG2 can induce apoptosis in PDAC cells in an AIF-dependent and caspase-independent
manner. 相似文献
75.
The 2001 UK foot and mouth disease (FMD) epidemic marked a change in global FMD management, focusing less on trade isolation than on biosecurity within countries where FMD is endemic. Post 2001 policy calls for the isolation of disease-free zones in FMD-endemic countries, while increasing the opportunities for trade. The impact of the change on disease risk has yet to be tested. In this paper, we estimate an empirical model of disease risk that tests for the impact of trade volumes before and after 2001, controlling for biosecurity measures. In the pre 2001 regime, we find that poor biosecurity was associated with the probability of reporting an outbreak. In the post 2001 regime, the risks changed, with trade being a much greater source of risk. We discuss the trade-off between trade restrictions and biosecurity measures in the management of FMD disease risks. 相似文献
76.
High variability in the MHC class II DA beta chain of the brushtail possum (<Emphasis Type="Italic">Trichosurus vulpecula</Emphasis>) 总被引:1,自引:0,他引:1
The diversity of class II major histocompatibility complex (MHC) loci was investigated in the brushtail possum, an important
marsupial pest species in New Zealand. Immunocontraception, a form of fertility control that generates an autoimmune response,
is being developed as a population control method for the possum. Because the immune response is partly under genetic control,
an understanding of immunogenetics in possum will be crucial to the development of immunocontraceptive vaccines. MHC molecules
are critical in the vertebrate immune response. Class II MHC molecules bind and present exogenously derived peptides to T
lymphocytes and may be important in the presentation of immunocontraceptives. We used polymerase chain reaction primers designed
to amplify the peptide binding region of possum class II MHC genes to isolate sequences from 49 animals. We have previously
described 19 novel alleles from the DAB locus in the possum (Holland et al., Immunogenetics 60:449–460, 2008). Here, we report on another 11 novel alleles isolated from possum DAB, making this the most diverse marsupial locus described so far. This high level of diversity indicates that DAB is an important MHC locus in the possum and will need to be taken into account in the design of immunocontraceptive vaccines. 相似文献
77.
Exposure of cells to ultraviolet radiation (UVR) is one of the best studied and most used model system for the examination
of the biological effects of DNA damage, its repair and tolerance. The major product after UVR treatment is cyclobutane pyrimidine
dimer (TT, TC, CC). Pyrimidine dimers are repaired by a direct reversal called photoreactivation or by excision of damage
in a process of nucleotide excision repair. Several methods have been developed for the detection and quantification of pyrimidine
dimers in DNA. The technique of Small and Greimann, in which DNA is incubated with the pyrimidine dimer-specific endonuclease,
was used for the analysis of mutant strains with impaired excision repair system of the unicellular green alga Chlamydomonas reinhardtii. Another method is based on the binding of specific monoclonal antibodies to pyrimidine dimers. The aim of our work was to
compare these two techniques with the use of mutant strains of C. reinhardtii — uvsX1 and uvsX2 which are assumed to be deficient in DNA damage recognition. One of their traits was sensitivity to UVR which could be caused
by breakdown of the excision repair pathway. The results suggest that the immuno-approach is suitable for the detection of
DNA damage induced by UVR.
Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia. 相似文献
78.
The aqueous substrate and product toxicity thresholds in the microbial biotransformation of (-)-trans-carveol to the fragrance/flavor compound (R)-(-)-carvone by Rhodococcus erythropolis were determined. Above aqueous phase concentrations of approx. 500 mg carveol/l and 200-600 mg carvone/l, the biotransformation activity of the biocatalyst was inhibited. This biotransformation was undertaken in a single aqueous phase 3 l [corrected] reactor in which a total of 5 ml carveol (mixture of isomers) was added before the biotransformation rate decreased significantly. The carvone volumetric productivity was 31 mg/lh. Although the growth of the organism post-exposure was not affected, dramatic morphological changes in response to the accumulation of the inhibitory substrate and product were observed. 相似文献
79.
Planarians are highly regenerative organisms with the ability to remake all their cell types, including the germ cells. The
germ cells have been suggested to arise from totipotent neoblasts through epigenetic mechanisms. Nanos is a zinc-finger protein
with a widely conserved role in the maintenance of germ cell identity. In this work, we describe the expression of a planarian
nanos-like gene Smednos in two kinds of precursor cells namely, primordial germ cells and eye precursor cells, during both development and regeneration
of the planarian Schmidtea mediterranea. In sexual planarians, Smednos is expressed in presumptive male primordial germ cells of embryos from stage 8 of embryogenesis and throughout development
of the male gonads and in the female primordial germ cells of the ovary. Thus, upon hatching, juvenile planarians do possess
primordial germ cells. In the asexual strain, Smednos is expressed in presumptive male and female primordial germ cells. During regeneration, Smednos expression is maintained in the primordial germ cells, and new clusters of Smednos-positive cells appear in the regenerated tissue. Remarkably, during the final stages of development (stage 8 of embryogenesis)
and during regeneration of the planarian eye, Smednos is expressed in cells surrounding the differentiating eye cells, possibly corresponding to eye precursor cells. Our results
suggest that similar genetic mechanisms might be used to control the differentiation of precursor cells during development
and regeneration in planarians.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
80.
We studied the life-history of the Sierra Madre sparrow (Xenospiza baileyi) in a subalpine grassland-agriculture mosaic south of Mexico City. From March to early September 1999 we captured and color-banded
53 adults with mist-nets and mapped the breeding territories of 21 males. We again mapped territories in the same spot in
April and May 2000. The number of breeding territories was found to be the same in the two consecutive years and interannual
survivorship was found to be relatively high. Breeding territories were restricted to the bunchgrass-covered areas. We used
the density of territories and the amount of remaining habitat to estimate a total population size of 5,380–6,150 adults for
this species. Using this and other recent data, we recommend raising the Sierra Madre sparrow to the status of critically
endangered using BirdLife International criteria. 相似文献