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131.
132.
Three iridoid glycosides 6-O-(3'-O-benzoyl)-alpha-l-rhamnopyranosylcatalpol (1a), 6-O-(3'-O-trans-cinnamoyl)-alpha-l-rhamnopyranosylcatalpol (2a) and 6-O-(3'-O-cis-cinnamoyl)-alpha-l-rhamnopyranosylcatalpol (3a) were isolated from aerial parts of Gmelina arborea and structures were elucidated by spectral analysis. Additionally a known iridoid 6-O-(3', 4'-O-dibenzoyl)-alpha-l-rhamnopyranosylcatalpol (4) was also isolated and identified. 相似文献
133.
Manoj K. Rai Pooja Asthana Shashi Kant Singh V.S. Jaiswal U. Jaiswal 《Biotechnology advances》2009,27(6):641-679
Encapsulation technology is an exciting and rapidly growing area of biotechnological research. This has drawn tremendous attention in recent years because of its wide use in conservation and delivery of tissue cultured plants of commercial and economic importance. Production of synthetic seeds by encapsulating somatic embryos, shoot buds or any other meristmatic tissue helps in minimizing the cost of micropropagated plantlets for commercialization and final delivery. In most of fruit crops, seed propagation has not been successful because of heterozygosity of seeds, minute seed size, presence of reduced endosperm, low germination rate, and also some are having seedless varieties. Many species have desiccation-sensitive intermediate or recalcitrant seeds and can be stored for only a few weeks or months. Under these circumstances, increasing interest has been shown recently to use encapsulation technology for propagation and conservation. Many fruit plants are studied worldwide for breeding, genetic engineering, propagation, and pharmaceutical purposes. In this context, synthetic seeds would be more applicable in exchange of elite and axenic plant material between laboratories and extension centers due to small bead size and ease in handling. Due to these advantages, interest in using encapsulation technology has continuously been increasing in several fruit plant species. The purpose of this review is to focus upon current information on development of synthetic seeds in several fruit crops. 相似文献
134.
The aerobic nitrogen fixing xylanolytic bacterium Paenibacillus pabuli strain ATSKP produces loosely attached capsular polysaccharide KP-EPS. On 0.5% birchwood xylan 70 ± 5.02 mg of KP-EPS was
produced per gram dry weight of cells by the fourth day of growth in the absence of combined nitrogen source at 30°C. It was
separated and purified using centrifugation, cold acetone precipitation and dialysis and is a sulfate containing heteropolymer
as revealed by FT-IR spectrometry and elemental analysis. CHN analysis revealed the presence of 37.50% carbon, 5.90% hydrogen
and 8.28% nitrogen in KP-EPS. Absence of phosphorus was confirmed by 31P NMR. ICP-OES analysis showed the presence of various metals in small concentrations. Specific binding with aniline blue
suggested the presence of (1,3)-β-d-glucan. Thermal gravimetric analysis and differential scanning calorimetric analysis confirmed its thermal stability as high
as 200°C. The EPS was not pseudo plastic and the viscosity was less than xanthan. The intrinsic viscosity did not reduce drastically
when dissolved in 0.1 M NaCl. 相似文献
135.
Traditional concealed information paradigms rely on the idea that stimuli that are meaningful to a person (critical items)
will draw attentional resources disproportionately, relative to stimuli that are not (irrelevant items), generating detectable
differences on a suitable dependent variable (behavioral, psychophysiological, or neural). Here, we introduce a behavioral
paradigm that could be used to reveal concealed information by exploiting the link between concealed information and attentional
processes more directly. This novel paradigm is based on the attentional blink phenomenon in which detection of a stimulus
reduces detection accuracy rates of subsequent target stimuli within a 200–500 ms time window. We hypothesized that a well-known
face used as a critical item could capture attentional resources automatically, making it harder to detect the occurrence
of a subsequently presented target face. The results confirmed this hypothesis, and showed that concealed knowledge of a famous
face could be detected in 9 out of 12 individuals by looking for a relative dip in target detection accuracy after the presentation
of a critical item. 相似文献
136.
Jason J. Paxman Natalie A. Borg James Horne Philip E. Thompson Yanni Chin Pooja Sharma Jamie S. Simpson Jerome Wielens Susannah Piek Charlene M. Kahler Harry Sakellaris Mary Pearce Stephen P. Bottomley Jamie Rossjohn Martin J. Scanlon 《The Journal of biological chemistry》2009,284(26):17835-17845
Oxidative protein folding in Gram-negative bacteria results in the formation of disulfide bonds between pairs of cysteine residues. This is a multistep process in which the dithiol-disulfide oxidoreductase enzyme, DsbA, plays a central role. The structure of DsbA comprises an all helical domain of unknown function and a thioredoxin domain, where active site cysteines shuttle between an oxidized, substrate-bound, reduced form and a DsbB-bound form, where DsbB is a membrane protein that reoxidizes DsbA. Most DsbA enzymes interact with a wide variety of reduced substrates and show little specificity. However, a number of DsbA enzymes have now been identified that have narrow substrate repertoires and appear to interact specifically with a smaller number of substrates. The transient nature of the DsbA-substrate complex has hampered our understanding of the factors that govern the interaction of DsbA enzymes with their substrates. Here we report the crystal structure of a complex between Escherichia coli DsbA and a peptide with a sequence derived from a substrate. The binding site identified in the DsbA-peptide complex was distinct from that observed for DsbB in the DsbA-DsbB complex. The structure revealed details of the DsbA-peptide interaction and suggested a mechanism by which DsbA can simultaneously show broad specificity for substrates yet exhibit specificity for DsbB. This mode of binding was supported by solution nuclear magnetic resonance data as well as functional data, which demonstrated that the substrate specificity of DsbA could be modified via changes at the binding interface identified in the structure of the complex. 相似文献
137.
Synthesis of Highly Immunogenic Multiple Antigenic Peptides for Epitopes of Viral Antigen to Use in ELISA 总被引:1,自引:0,他引:1
Paramasivam Saravanan Sameer Shrivastava Satish Kumar 《International journal of peptide research and therapeutics》2009,15(4):313-321
Synthesis of multiple antigenic peptides (MAPs) for predicted antigenic determinants of a viral antigen is described. The
method includes prediction of linear epitopes using predictive computer algorithms, synthesis of peptides for the predicted
regions, testing of peptides to find the most reactive sites, synthesis of MAPs and their testing. The procedure involves
manual synthesis of MAPs by solid phase peptide synthesis with Wang resin as solid support. The MAPs were prepared in eight
copies and used for immunization of rabbits to generate anti-peptide antibodies. Further, the reactivity of MAPs in detecting
the native cognate antigen in the whole virus was confirmed by ELISA. The MAP and anti-peptide antibodies could serve as diagnostic
tools for viral diseases. MAPs have efficiently been used to confirm the presence of linear antigenic and immunogenic epitopes
on viral proteins, for possible use in diagnostic and vaccine. It was suggested that this method could help in epitope mapping
of dreadful human or animal pathogens as it involves production of safe, chemically defined and non-infectious materials for
use as antigen as well as immunogen. 相似文献
138.
Dihedral angles of amino acids are of considerable importance in protein tertiary structure prediction as they define the backbone of a protein and hence almost define the protein's entire conformation. Most ab initio protein structure prediction methods predict the secondary structure of a protein before predicting the tertiary structure because three-dimensional fold consists of repeating units of secondary structures. Hence, both dihedral angles and secondary structures are important in tertiary structure prediction of proteins. Here we describe a database called DASSD (Dihedral Angle and Secondary Structure Database of Short Amino acid Fragments) that contains dihedral angle values and secondary structure details of short amino acid fragments of lengths 1, 3 and 5. Information stored in this database was extracted from a set of 5,227 non-redundant high resolution (less than 2-angstroms) protein structures. In total, DASSD stores details for about 733,000 fragments. This database finds application in the development of ab initio protein structure prediction methods using fragment libraries and fragment assembly techniques. It is also useful in protein secondary structure prediction.
Availability 相似文献
139.
Background
Emotional states linked to arousal and mood are known to affect the efficiency of cognitive performance. However, the extent to which memory processes may be affected by arousal, mood or their interaction is poorly understood.Methodology/Principal Findings
Following a study phase of abstract shapes, we altered the emotional state of participants by means of exposure to music that varied in both mood and arousal dimensions, leading to four different emotional states: (i) positive mood-high arousal; (ii) positive mood-low arousal; (iii) negative mood-high arousal; (iv) negative mood-low arousal. Following the emotional induction, participants performed a memory recognition test. Critically, there was an interaction between mood and arousal on recognition performance. Memory was enhanced in the positive mood-high arousal and in the negative mood-low arousal states, relative to the other emotional conditions.Conclusions/Significance
Neither mood nor arousal alone but their interaction appears most critical to understanding the emotional enhancement of memory. 相似文献140.
Pungaliya PP Bai Y Lipinski K Anand VS Sen S Brown EL Bates B Reinhart PH West AB Hirst WD Braithwaite SP 《PloS one》2010,5(10):e13672
Mutations in LRRK2 (leucine-rich repeat kinase 2) have been identified as major genetic determinants of Parkinson's disease (PD). The most prevalent mutation, G2019S, increases LRRK2's kinase activity, therefore understanding the sites and substrates that LRRK2 phosphorylates is critical to understanding its role in disease aetiology. Since the physiological substrates of this kinase are unknown, we set out to reveal potential targets of LRRK2 G2019S by identifying its favored phosphorylation motif. A non-biased screen of an oriented peptide library elucidated F/Y-x-T-x-R/K as the core dependent substrate sequence. Bioinformatic analysis of the consensus phosphorylation motif identified several novel candidate substrates that potentially function in neuronal pathophysiology. Peptides corresponding to the most PD relevant proteins were efficiently phosphorylated by LRRK2 in vitro. Interestingly, the phosphomotif was also identified within LRRK2 itself. Autophosphorylation was detected by mass spectrometry and biochemical means at the only F-x-T-x-R site (Thr 1410) within LRRK2. The relevance of this site was assessed by measuring effects of mutations on autophosphorylation, kinase activity, GTP binding, GTP hydrolysis, and LRRK2 multimerization. These studies indicate that modification of Thr1410 subtly regulates GTP hydrolysis by LRRK2, but with minimal effects on other parameters measured. Together the identification of LRRK2's phosphorylation consensus motif, and the functional consequences of its phosphorylation, provide insights into downstream LRRK2-signaling pathways. 相似文献