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991.
Zichen?Zhang Jianghua?Li Long?LiuEmail author Jun?Sun Zhaozhe?Hua Guocheng?Du Jian?Chen 《Biotechnology and Bioprocess Engineering》2011,16(1):107-113
The study aimed to produce 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) via the transglycosylation reaction by α-cyclodextrin glucanotransferase (α- CGTase) from recombinant Escherichia coli with L-ascorbic acid (AA) and β-cyclodextrin (β-CD) as the substrates. Liquid chromatography-tandem mass spectrometry analysis
was conducted for AA-2G identification, and the glucoamylase treatment was carried out to produce AA-2G from AA-2-oilgosaccharides.
The optimal temperature and pH for the enzymatic AA-2G production were 37°C and 5.5, respectively, and the optimal α-CGTase
concentration and substrate mass ratio (AA:β-CD) for AA-2G synthesis were 160 U/mL and 1:1, respectively. At these optimal
process conditions, maximal AA-2G production reached 13 g/L. This is the first report regarding the process optimization of
enzymatic AA-2G production by α-CGTase from recombinant E. coli. The results may be useful for the industrial scale production of AA-2G. 相似文献
992.
Cocoon sericin plays an important role in the reeling of silk and serves as a valuable biomaterial in the field of biomedicine,
skincare, and food industries; however, knowledge about cocoon sericin proteins has been limited. For a comprehensive study
on sericin, cocoons of eight varieties of silkworm of different geographic origin and with varied cocoon color were analyzed
utilizing proteomics and bioinformatics approaches. The electrophoresis pattern demonstrated some common protein bands for
all silkworm varieties and distinctive protein bands for some of those examined in the present study. The Ser2 protein, a
new Ser3 protein, and four other novel sericin proteins were identified in cocoons for the first time. Products of both Ser1
and Ser3 genes appear to be ubiquitous in the cocoon shell of Bombyx mori. In addition, cocoons with especially high-reelability produced by the mutant strain B84 had an unique protein product of
the Ser2 gene, indicating that the protein may play an important role in cocoon reelability. A series of sequence conflicts and post-translational
modifications (PTMs) were also revealed in sericin proteins. Lipid modifications of sericin proteins, which promote waterproofing
of the cocoon shell, were observed. Further, hydroxylation was identified, which provided evidence for intermolecular bonds
among neighboring molecules of sericin as found in collagens. The sericin proteome data obtained from this study illuminated
the molecular complexity of cocoon sericin and contributed to our understanding of the properties of sericin in filature and
biomaterials. 相似文献
993.
994.
995.
We assessed SLC27A1, a candidate gene for milk production traits in Chinese Holstein cattle. DNA was extracted from the blood of 48 top Chinese Holstein Cattle selected according to phenotypic character and mixed into DNA pool for SNP detection. We tested blood samples of these cattle for SNPs in exon 3 and the 3'-flanking region of the SLC27A1 gene by using polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) and DNA sequencing. We found 2 polymorphic sites: 112T>C, a synonymous mutation, in exon 3 (SNP(1)), and 64G>A in the 3'-UTR (SNP(2)). We also determined the genotypes of 330 Chinese Holstein cattle by using PCR-restriction fragment length polymorphism (RFLP). We found 3 genotypes each at SNP(1) (TT, TC, and CC) and SNP(2) (GG, GA, and AA). The association among the different genotypes at these 2 sites and milk production traits was analyzed using a least-squares procedure. The results showed that cows with genotype CC had higher milk yields than those with genotype TC (0.01 < p < 0.05). No significant difference was detected among the 3 SNP(2) genotypes in terms of milk production traits. Our results provide evidence that the C allele have potential effects on milk yield trait. 相似文献
996.
Qian Y Du YH Tang YB Lv XF Liu J Zhou JG Guan YY 《Apoptosis : an international journal on programmed cell death》2011,16(5):468-477
ClC-3 Cl− channel plays an important role in cell volume regulation and cell cycle. In vascular smooth muscle cells, we have found
that ClC-3 was involved in ET-1 induced cell proliferation. The present study was designed to further investigate the role
of ClC-3 Cl− channel in H2O2-induced apoptosis and its underlying mechanisms in rat basilar arterial smooth muscle cell (BASMCs). By using ClC-3 cDNA
and small interference RNA (siRNA) transfection strategy, it was found that overexpression of ClC-3 significantly decreased
the apoptotic rate of H2O2-treated BASMCs and increased the cell viability, whereas silencing of ClC-3 with siRNA produced opposite effects and increased
the apoptotic rate. ClC-3 overexpression decreased cytochrome C release and caspase-3 activation, and increased both the stability
of mitochondrial membrane potential and the ratio of Bcl-2/Bax, whereas silencing of ClC-3 produced opposite effect. Furthermore,
we demonstrated that overexpression of ClC-3 attenuated, whereas silencing of ClC-3 facilitated, the degradation of LaminA,
one of the structural matrix proteins, in BASMCs. Our data suggest that ClC-3 Cl− channel can modulate H2O2-induced apoptosis in BASMCs via the intrinsic, mitochondrial pathway. 相似文献
997.
Severe acute pancreatitis (SAP) is a common disease with a poor prognosis. Heart failure is one cause of SAP patient death.
Intermedin (IMD) is a potent endogenous cardio-protective substance. Administration of exogenous IMD showed beneficial effects
in cardiovascular diseases. The aim of this study was to investigate the myocardial damage in SAP and to determine the therapeutic
potential of IMD for SAP. Using an SAP rat model, we examined endogenous IMD expression following SAP induction, and determined
the effect of IMD on myocardial function, histological morphology, apoptosis-related gene expression, and prognosis. Our results
indicated that the cardiac function and histological structure were significantly disrupted in SAP rats. Infusion of exogenous
IMD significantly preserved cardiac function and ameliorated myocardial damage. Terminal deoxynucleotidyl transferase-mediated
dUTP nick end labeling (TUNEL) revealed that myocardial apoptosis was extensively present in SAP rats, and IMD infusion led
to increased expression of the prosurvival factor Bcl-2, but decreased pro-apoptotic factors Bax and caspase-3. In addition,
IMD infusion also reversed the change of IMD receptor systems in SAP rat heart tissue. Furthermore, we found that IMD infusion
greatly decreased mortality of SAP rats. In conclusion, administration of SAP produced therapeutic effects in SAP through
modulating apoptotic and pro-survival gene expression, inhibiting myocardial apoptosis, preserving cardiac function, and a
useful therapeutic agent for SAP, and provides us an insight for a clinical trial of IMD for treating human severe acute pancreatitis. 相似文献
998.
For alpine plant species, patterns of resource allocation to functional floral traits for pollinator attraction can be highly significant in adaptation to low pollinator abundance and consequent pollen limitation. Increased pollination can be achieved either through a larger floral display or production of more pollen rewards. In this study, variation in resource allocation to different components for pollinator attraction was studied along an altitudinal gradient in Trollius ranunculoides, an obligate self‐incompatible out‐crosser of the Qinghai–Tibet Plateau. We compared resource allocation to conspicuous yellow sepals (which mainly provide visual attraction) and degenerate petals (which provide the major nectar reward) between populations at four altitudes. Furthermore, we investigated the contribution of sepals and petals to pollinator attraction and female reproductive success in an experiment with sepal or petal removal at sites at different altitudes. At the level of single flowers, resource allocation increased to sepals but decreased to petals with increasing altitude. Consistent with these results, sepals contributed much more to visitation rate and seed set than petals, as confirmed in the sepal or petal removal experiment. Sepals and petals contributed to female reproductive success by ensuring visitation rate rather than visitation duration. To alleviate increasing pollen limitation with increasing altitude, resource allocation patterns of T. ranunculoides altered to favour development of sepals rather than petals. This strategy may improve pollination and reproductive success through visual attraction (sepal) rather than nectar reward (petal) over a gradient of decreasing pollinator abundance. 相似文献
999.
Li Z Zhou M Zhang Z Ren L Du L Zhang B Xu H Xin Z 《Functional & integrative genomics》2011,11(1):63-70
Fusarium head blight (scab), primarily caused by Fusarium graminearum, is a devastating disease of wheat (Triticum aestivum L.) worldwide. Wheat sharp eyespot, mainly caused by Rhizoctonia cerealis, is one of the major diseases of wheat in China. The defensin RsAFP2, a small cyteine-rich antifungal protein from radish
(Raphanus sativus), was shown to inhibit growth in vitro of agronomically important fungal pathogens, such as F. graminearum and R. cerealis. The RsAFP2 gene was transformed into Chinese wheat variety Yangmai 12 via biolistic bombardment to assess the effectiveness of the defensin
in protecting wheat from the fungal pathogens in multiple locations and years. The genomic PCR and Southern blot analyses
indicated that RsAFP2 was integrated into the genomes of the transgenic wheat lines and heritable. RT-PCR and Western blot proved that the RsAFP2 was expressed in these transgenic wheat lines. Disease tests showed that four RsAFP2 transgenic lines (RA1–RA4) displayed enhanced resistance to F. graminearum compared to the untransformed Yangmai 12 and the null-segregated plants. Assays on Q-RT-PCR and disease severity showed that
the express level of RsAFP2 was associated with the enhanced resistance degree. Two of these transgenic lines (RA1 and RA2) also exhibited enhanced resistance
to R. cerealis. These results indicated that the expression of RsAFP2 conferred increased resistance to F. graminearum and R. cerealis in transgenic wheat. 相似文献
1000.
Prlainović NZ Knežević-Jugović ZD Mijin DZ Bezbradica DI 《Bioprocess and biosystems engineering》2011,34(7):803-810
The objective of this paper was the investigation of a suitable Sepabeads? support and method for immobilization of lipase from Candida rugosa. Three different supports were used, two with amino groups, (Sepabeads? EC-EA and Sepabeads? EC-HA), differing in spacer length (two and six carbons, respectively) and one with epoxy group (Sepabeads? EC-EP). Lipase immobilization was carried out by two conventional methods (via epoxy groups and via glutaraldehyde), and
with periodate method for modification of lipase. The results of activity assays showed that lipase retained 94.8% or 87.6%
of activity after immobilization via epoxy groups or with periodate method, respectively, while glutaraldehyde method was
inferior with only 12.7% of retention. The immobilization of lipase, previously modified by periodate oxidation, via amino
groups has proven to be more efficient than direct immobilization of lipase via epoxy groups. In such a way immobilized enzyme
exhibited higher activity at high reaction temperatures and higher thermal stability. 相似文献