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981.
Arezou Ghahghaei Jafar Valizadeh Shahrzad Nazari Mehdi Ravandeh 《AAPS PharmSciTech》2014,15(3):658-664
This study examined the effect of an aqueous extract of Pulicaria undulata on the 1,4-dithiothreitol (DTT)-induced aggregation of proteins. The effects of the chaperone properties of P. undulata extract on protein aggregation were determined by measuring light scattering absorption, fluorescence, and circular dichroism (CD) spectroscopy. The aqueous extract of P. undulata possesses good chaperone properties but the protection effect was varied in different protein. The extract showed a higher level of protection in high molecular weight proteins than in those of low molecular weight. Using a fluorescence study, the present study provides information on the hydrophobic area of proteins interacting with the P. undulata extract. In fact, by increasing the concentration of the P. undulata extract, the hydrophic area of the protein decreased. CD spectroscopy also revealed that DTT caused changes in both the tertiary and the secondary structure of the proteins, while in the presence of P. undulata extract, there was little change. Our finding suggests the possibility of using P. undulata extract for the inhibition of aggregation and the deposition of protein in disease. 相似文献
982.
Yiping Wang Xiaojian Zhang Qing Liu Chenbing Ai Hongyu Mo Jia Zeng 《Current microbiology》2009,59(1):35-41
The thioredoxin system consists of thioredoxin (Trx), thioredoxin reductase (TrxR) and NADPH, which plays several key roles
in maintaining the redox environment of the cell. In Acidithiobacillus ferrooxidans, thioredoxin system may play important functions in the activity regulation of periplasmic proteins and energy metabolism.
Here, we cloned thioredoxin (trx) and thioredoxin reductase (trxR) genes from Acidithiobacillus ferrooxidans, and expressed the genes in Escherichia coli. His-Trx and His-TrxR were purified to homogeneity with one-step Ni-NTA affinity column chromatography. Site-directed mutagenesis
results confirmed that Cys33, Cys36 of thioredoxin, and Cys142, Cys145 of thioredoxin reductase were active-site residues. 相似文献
983.
Huaiyang?Zhou Jiangtao?LiEmail author Xiaotong?Peng Jun?Meng Fengping?Wang Yuncan?Ai 《Journal of microbiology (Seoul, Korea)》2009,47(3):235-247
Submarine hydrothermal vents are among the least-understood habitats on Earth but have been the intense focus of research
in the past 30 years. An active hydrothermal sulfide chimney collected from the Dudley site in the Main Endeavour vent Field
(MEF) of Juan de Fuca Ridge was investigated using mineralogical and molecular approaches. Mineral analysis indicated that
the chimney was composed mainly of Fe-, Zn-and Cu-rich sulfides. According to phylogenetic analysis, within the Crenarchaeota,
clones of the order Desulfurococcales predominated, comprising nearly 50% of archaeal clones. Euryarchaeota were composed mainly of clones belonging to Thermococcales and deep-sea hydrothermal vent Euryarchaeota (DHVE), each of which accounted for about 20% of all clones. Thermophilic or hyperthermophilic physiologies were common to
the predominant archaeal groups. More than half of bacterial clones belonged to ɛ-Proteobacteria, which confirmed their prevalence in hydrothermal vent environments. Clones of Proteobacteria (γ-, δ-, β-), Cytophaga-Flavobacterium-Bacteroides (CFB) and Deinococcus-Thermus occurred as well. It was remarkable that methanogens
and methanotrophs were not detected in our 16S rRNA gene library. Our results indicated that sulfur-related metabolism, which
included sulfur-reducing activity carried out by thermophilic archaea and sulfur-oxidizing by mesophilic bacteria, was common
and crucial to the vent ecosystem in Dudley hydrothermal site. 相似文献
984.
985.
Luke H. Bradley Josh Fuqua April Richardson Jadwiga Turchan-Cholewo Yi Ai Kristen A. Kelps John D. Glass Xiuquan He Zhiming Zhang Richard Grondin O. Meagan Littrell Peter Huettl Francois Pomerleau Don M. Gash Greg A. Gerhardt 《PloS one》2010,5(3)
Background
Neurotrophic factors, such as glial cell line-derived neurotrophic factor (GDNF), have shown great promise for protection and restoration of damaged or dying dopamine neurons in animal models and in some Parkinson''s disease (PD) clinical trials. However, the delivery of neurotrophic factors to the brain is difficult due to their large size and poor bio-distribution. In addition, developing more efficacious trophic factors is hampered by the difficulty of synthesis and structural modification. Small molecules with neurotrophic actions that are easy to synthesize and modify to improve bioavailability are needed.Methods and Findings
Here we present the neurobiological actions of dopamine neuron stimulating peptide-11 (DNSP-11), an 11-mer peptide from the proGDNF domain. In vitro, DNSP-11 supports the survival of fetal mesencephalic neurons, increasing both the number of surviving cells and neuritic outgrowth. In MN9D cells, DNSP-11 protects against dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA)-induced cell death, significantly decreasing TUNEL-positive cells and levels of caspase-3 activity. In vivo, a single injection of DNSP-11 into the normal adult rat substantia nigra is taken up rapidly into neurons and increases resting levels of dopamine and its metabolites for up to 28 days. Of particular note, DNSP-11 significantly improves apomorphine-induced rotational behavior, and increases dopamine and dopamine metabolite tissue levels in the substantia nigra in a rat model of PD. Unlike GDNF, DNSP-11 was found to block staurosporine- and gramicidin-induced cytotoxicity in nutrient-deprived dopaminergic B65 cells, and its neuroprotective effects included preventing the release of cytochrome c from mitochondria.Conclusions
Collectively, these data support that DNSP-11 exhibits potent neurotrophic actions analogous to GDNF, making it a viable candidate for a PD therapeutic. However, it likely signals through pathways that do not directly involve the GFRα1 receptor. 相似文献986.
Itaru Hirai Tadahiro Sasaki Ai Kimoto Yoshimasa Yamamoto Takeshi Azuma Varocha Mahachai Piyathida Hansomburana Comsun Lertkupinit Somchai Luangjaru Phadet Noophan Rattikorn Chanatrirattanapan Vanich Piyanirandr Theeranan Sappajit Karun Suthivarakom Leelaowadee Sangsuk Piyada Wangroongsarb 《Microbes and infection / Institut Pasteur》2010,12(3):227-230
In Thailand, gastric cancer incidence is considerably low despite the high prevalence of Helicobacter pylori infection. We investigated the prevalence of H. pylori infection and the genotypes of cagA by using 179 stool specimens obtained from asymptomatic Thai individuals. In this study, the prevalence of H. pylori infection was 43.6%, and the detection rate of cagA-positive strains was 43.5%. In addition, the proportion of the highly virulent East-Asian type of cagA was 7.2%. These results indicate that the low prevalence of cagA-positive H. pylori strain as well as the low prevalence of East-Asian genotype cagA-positive strains may contribute to the low gastric cancer incidence. 相似文献
987.
Laccases are industrially attractive enzymes and their applications have expanded to the field of bioremediation. The challenge of today's biotechnology in enzymatic studies is to design enzymes that not only have a higher activity but are also more stable and could fit well with the condition requirements. Laccases are known to oxidize non-natural substrates like polycyclic aromatic hydrocarbons (PAHs). We suppose by increasing the hydrophobicity of laccase, it would increase the chance of the enzyme to meet the hydrophobic substrates in a contamination site, therefore increasing the bioremediation efficacy of PAHs from environment. In this attempt, the applications of evolutionary trace (ET), molecular surface accessibility and hydrophobicity analysis on laccase sequences and laccase's crystal structure (1KYA) are described for optimal design of an enzyme with higher hydrophobicity. Our analysis revealed that Q23A, Q45I, N141A, Q237V, N262L, N301V, N331A, Q360L and Q482A could be promising exchanges to be tested in mutagenesis experiments. 相似文献
988.
Heng‐Chang Wang Ai‐Ping Meng Hai‐Jia Chu Xin‐Wei Li Jian‐Qiang Li 《Nordic Journal of Botany》2010,28(3):371-375
Using scanning electron microscopy, we studied the floral ontogeny of Sinojackia xylocarpa. There are 6–7 (–8) sepals. Sepal initiation is staggered; adaxial sepals arise later than abaxial and lateral ones. There are (5–) 6–7 (–8) petals, initiated simultaneously. Petals alternate with the sepals, and occasionally there are two petals instead of one between two sepals. The (10–) 12–14 (–16) stamens are initiated centripetally in two sets (whorls). These floral organ numbers deviate from those of the otherwise mostly pentamerous family Styracaceae. The ovary consists of three (rarely four) locules. In each of the locules, two rows of ovules are differentiated basipetally. Placentation is axile with (5–) 6 (–7) ovules in each locule. Ovules are unitegmic and are ascending with the micropyle directed downwards. Intra‐ovarian trichomes are present as in other representatives of Styracaceae and seem to be an apomorphic character of the family as they are absent in the closely related Symplocaceae and Diapensiaceae. Various levels of organ union occur in anthetic S. xylocarpa. The calyx is synsepalous and the ovary syncarpous. Possibly, the basal connation of petals and stamens is postgenital (and not congenital), but this needs further study. The outward curvature of the young anthers of the inner stamen whorl superficially simulates an obdiplostemonous androecium. However, the sequence of stamen initiation shows a diplostemonous pattern. 相似文献
989.
Ai Hua Chen Jing Li Yang Yu Da Niu Chuan Ping Yang Gui Feng Liu Chang Yeon Yu Cheng Hao Li 《Plant Cell, Tissue and Organ Culture》2010,102(3):357-364
We developed a new protocol for highly efficient somatic embryogenesis and plantlet conversion of Schisandra chinensis. Friable embryogenic callus was induced from cotyledonary leaves and hypocotyls of germinated zygotic embryos on Murashige
and Skoog (MS) agar medium containing 2,4-dichlorophenoxyacetic acid (2,4-D). Preculture of zygotic embryos on 2,4-D-containing
medium increased embryogenic callus induction efficiency. The highest embryogenic callus induction frequency of 56.7% was
obtained from shoot apical meristem-containing hypocotyl explants from 1-week-old germinated embryos on MS medium containing
4.0 mg l−1 2,4-D. Embryogenic callus proliferation, somatic embryo (SE) formation, and subsequent plantlet conversion occurred under
optimal culture conditions. The effects of MS medium strength, sucrose, gibberellic acid (GA3), and 6-benzyladenine (BA) on SE formation and plantlet conversion were evaluated. Low MS medium strength (1/4 to 1/2) was
necessary for SE formation, and the optimal sucrose concentration was 2.0%. Supplementing medium with GA3 negatively impacted SE formation and subsequent development. BA significantly increased the number of SEs and the plantlet
conversion capacity. One-third-strength MS medium with 1.0% sucrose and 0.5 mg l−1 BA produced the highest number of SEs (309 embryos from 9 mg embryogenic callus) and the highest frequency of plantlet conversion
from germinated SEs (52.6%). When transplanted to soil, 90% of the regenerated plants developed into normal plants. 相似文献
990.
Bristles along the wing margins (wm-bristles) of the silkworm moth, Bombyx mori, were studied morphologically and electrophysiologically. The male moth has ca. 50 wm-bristles on each forewing and hindwing. Scanning electron microscopy revealed that these wm-bristles are typical mechanosensilla. Leuco-methylene blue staining demonstrated that each wm-bristle has a single receptor neuron, which is also characteristic of the mechanosensillum. The receptor neuron responded to vibrating air currents but did not respond to a constant air current. The wm-bristles showed clear directional sensitivity to vibrating air currents. The wm-bristles were classified into two types, type I and type II, by their response patterns to sinusoidal movements of the bristle. The neuron in type I discharged bursting spikes immediately following stimulation onset and also discharged a single spike for each sinusoidal cycle for frequencies less than ca. 60 Hz. The neuron in type II only responded to vibrations over 40 Hz and, specifically at 75 Hz, discharged a single spike for each sinusoidal cycle throughout the stimulation period. These results suggest that the two types of wm-bristles are highly tuned in different ways to detect vibrations due to the wing beat. The roles of the wm-bristles in the wing beat are discussed. 相似文献