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排序方式: 共有714条查询结果,搜索用时 21 毫秒
101.
Archana Unnikrishnan Stephanie Matyi Karla Garrett Michelle RanjoBishop David B. Allison Keisuke Ejima Xiwei Chen Stephanie Dickinson Arlan Richardson 《Aging cell》2021,20(11)
Dietary restriction (DR) was reported to either have no effect or reduce the lifespan of the majority of the 41‐recombinant inbred (RI) lines studied by Liao et al. (Aging Cell, 2010, 9, 92). In an appropriately power longevity study (n > 30 mice/group), we measured the lifespan of the four RI lines (115‐RI, 97‐RI, 98‐RI, and 107‐RI) that were reported to have the greatest decrease in lifespan when fed 40% DR. DR increased the median lifespan of female RI‐115, 97‐RI, and 107‐RI mice and male 115‐RI mice. DR had little effect (<4%) on the median lifespan of female and male 98‐RI mice and male 97‐RI mice and reduced the lifespan of male 107‐RI mice over 20%. While our study was unable to replicate the effect of DR on the lifespan of the RI mice (except male 107‐RI mice) reported by Liao et al. (Aging Cell, 2010, 9, 92), we found that the genotype of a mouse had a major impact on the effect of DR on lifespan, with the effect of DR ranging from a 50% increase to a 22% decrease in median lifespan. No correlation was observed between the changes in either body composition or glucose tolerance induced by DR and the changes observed in lifespan of the four RI lines of male and female mice. These four RI lines of mice give the research community a unique resource where investigators for the first time can study the anti‐aging mechanism of DR by comparing mice in which DR increases lifespan to mice where DR has either no effect or reduces lifespan. 相似文献
102.
Maria John Newton Amaldoss Imtiyaz Ahmed Najar Jatinder Kumar Archana Sharma 《Reports of Practical Oncology and Radiotherapy》2021,26(5):712
BackgroundRifaximin is a non-systemic antibiotic used in the treatment of inflammatory bowel disease (IBD). Antibiotics are demonstrating a significant role in the treatment of IBD by altering the dysbiotic colonic microbiota and decreases the immunogenic and inflammatory response in the patient population. Mucoadhesive colon targeted nanoparticles provide the site-specific delivery and extended stay in the colon. Since the bacteria occupy the lumen, spread over the surface of epithelial cells, and adhere to the mucosa, delivering the rifaximin as a nanoparticles with the mucoadhesive polymer enhances the therapeutic efficacy in IBD. The objective was to fabricate and characterize the rifaximin loaded tamarind gum nanoparticles and study the therapeutic efficacy in the TNBS-induced IBD model ratsMaterials and methodsThe experimentation includes fabrication and characterization of drug excipient compatibility by FTIR. The fabricated nanoparticles were characterized for the hydrodynamic size and zeta potential by photon correlation spectroscopy and also analyzed by TEM. Selected best formulation was subjected to the therapeutic efficacy study in TNBS-induced IBD rats, and the macroscopic, microscopic and biochemical parameters were reported.ResultsThe study demonstrated that the formulation TGN1 is best formulation in terms of nanoparticle characterization and hydrodynamic size which showed the hydrodynamic size of 171.4 nm and the zeta potential of −26.44 mV and other parameters such as TEM and drug release studies were also reported.ConclusionsThe therapeutic efficacy study revealed that TGN1 is efficiently reduced the IBD inflammatory conditions as compared to the TNBS control group and reference drug mesalamine group. 相似文献
103.
Gayathri Bathoju Kiranmayee Rao Archana Giri 《Plant Cell, Tissue and Organ Culture》2017,131(3):369-376
Chlorophytum borivilianum belonging to the family Liliaceae, is distributed in the pantropical regions of India and South Africa. The sapogenins (stigmasterol and hecogenin) of C. borivilianum are well known for their appetizing and aphrodisiac properties. The present study involves enhancing the sapogenin content in C. borivilianum by genetic transformations with Agrobacterium rhizogenes strains (MTCC 2364 and 532, PRT Gus). A maximum transformation frequency of 98% was obtained with Agrobacterium rhizogenes MTCC 2364 strain with rhizome explants after a co-cultivation period of 48 h. Two potential rhizoclones (2364a and 2364b) were selected for the production of stigmasterol and hecogenin. The maximum production of stigmasterol (83.952?±?0.01 mg/g) was seen in 2364b rhizoclone, whereas, the highest accumulation of hecogenin (81.52?±?0.02 mg/g) was observed in 2364a rhizoclone. The C. borivilianum hairy root cultures obtained in this study provide a continuous and sustainable production of stigmasterol and hecogenin on a commercial scale. 相似文献
104.
Verma A Sharma S Ganguly NK Majumdar S Guptasarma P Luthra-Guptasarma M 《The international journal of biochemistry & cell biology》2008,40(4):663-676
The N-terminal 'unstructured' region of the human prion protein [PrP((90-231))] is believed to play a role in its aggregation because mutations in this region are associated with seeding-independent deposition disorders like Gerstmann-Straussler-Scheinker disease (GSS). One way of examining the effects of such mutations is to search combinatorially derived libraries for sequence variants showing a propensity to aggregate and/or the ability to interact with prion molecules folded into a beta-sheet-based conformation (i.e., beta-PrP or PrP(Sc)). We created a library of 1.8x10(7) variants randomized between positions 101 and 112, displayed it on filamentous bacteriophage, and 'spiked' it with a approximately 25% population of phages-bearing wild-type prion (wt-PrP). Screening was performed through four rounds of biopanning and amplification against immobilized beta-PrP, and yielded three beta-PrP-binding populations: wt-PrP (26% representation) and two non-wt-PrP variants ( approximately 10% and approximately 64% representation, respectively). The remarkable enrichment of one non-wt-PrP variant (MutPrP) incorporating residues KPSKPKTNMKHM in place of KGVLTWFSPLWQ, despite its initial representation at a 5 million-fold lower level than wt-PrP, caused us to produce it and discover: (i) that it readily aggregates into thioflavin-T-binding amyloids between pH 6.0 and 9.0, (ii) that it adopts a soluble beta-sheet based monomeric structure at pH 10.0, (iii) that it is less thermally stable and more compact than wt-PrP, and (iv) that it displays significantly greater resistance to proteolysis than wt-PrP. Our results suggest that sequence variations in the 101-112 region can indeed predispose the prion for aggregation. 相似文献
105.
Patel SD Habeski WM Min H Zhang J Roof R Snyder B Bora G Campbell B Li C Hidayetoglu D Johnson DS Chaudhry A Charlton ME Kablaoui NM 《Bioorganic & medicinal chemistry letters》2008,18(20):5689-5693
The discovery of the CNS-penetrant and selective alpha(2C) adrenergic receptor antagonist N-{2-[4-(2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl)-[1,4]diazepan-1-yl]-ethyl}-2-phenoxy-nicotinamide, 13 is described. Structure-activity studies demonstrate the structural requirements for binding affinity, functional activity, and selectivity over other alpha(2)-AR subtypes. 相似文献
106.
Archana Jha 《Biophysical journal》2009,96(10):4075-4084
We studied single-channel currents from neuromuscular acetylcholine receptor-channels with mutations in the pore-lining, M2 helix of the ɛ-subunit. Three parameters were quantified: 1), the diliganded gating equilibrium constant (E2), which reflects the energy difference between C(losed) and O(pen) conformations; 2), the correlation between the opening rate constant and E2 on a log-log scale (Φ), which illuminates the energy character of the residue (C- versus O-like) within the C↔O isomerization process; and 3), the open-channel current amplitude (i0), which reports whether a mutation alters the energetics of ion permeation. The largest E2 changes were observed in the cytoplasmic half of ɛM2 (5′, 9′, 12′, 13′, and 16′), with smaller changes apparent for residues ≥17′. Φ was ∼0.54 for most ɛM2 residues, but was ∼0.32 at the positions that had largest E2 changes. An arginine substitution reduced i0 significantly at six positions, with the magnitude of the reduction increasing, 16′→2′. The measurements suggest that the 9′, 12′, and 13′ residues experience large and late free-energy changes in the channel-opening process. We speculate that in the gating isomerization the pore-facing residues >6′ and <16′ experience multiple energy perturbations associated with changes in protein structure and, perhaps, hydration. 相似文献
107.
Yasmin J. Cardoza Archana Vasanthakumar Alonso Suazo & Kenneth F. Raffa 《Entomologia Experimentalis et Applicata》2009,131(2):138-147
In a recent study, we reported a previously undescribed behavior in which a bark beetle exuded oral secretions containing bacteria that have antifungal properties, and hence defend their galleries against pervasive antagonistic Hyphomycete fungi. Actinobacteria, a group known for their antibiotic properties, were the most effective against fungi that invade the spruce beetle galleries. In the present study, we describe the isolation and identification of microorganisms from oral secretions of three bark beetles (Coleoptera: Curculionidae: Scolytinae): the spruce beetle, Dendroctonus rufipennis Kirby, the mountain pine beetle, Dendroctonus ponderosae Hopkins, and the pine engraver, Ips pini Say. Bacteria isolated from these three species span the major bacterial classes α-, β-, and γ-Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, except for D. ponderosae , which yielded no α-proteobacteria or Bacteroidetes isolates. Spruce beetles and pine engraver beetles had similar numbers of α-proteobacteria isolates, but pine engravers yielded twice as many Bacteroidetes isolates as spruce beetles. In contrast, mountain pine beetles yielded more isolates in the β- and γ-proteobacteria than spruce beetles and pine engravers. The highest percentage of Actinobacteria was obtained from spruce beetles, followed by pine engravers and mountain pine beetles. All of the fungal isolates obtained from the three beetle species were Ascomycetes. The greatest fungal diversity was obtained in spruce beetles, which had nine species, followed by pine engravers with five, and mountain pine beetles with one. 相似文献
108.
109.
Vandana Singh Archana Srivastava Ashutosh Tiwari 《International journal of biological macromolecules》2009,45(3):293-297
A water-soluble seed gum was isolated from seed endosperm of Cassia javahikai. The acid-catalyzed fragmentation, methylation, selective enzymatic degradation and periodate oxidation suggested a heteropolymeric structure for the polysaccharide. The polysaccharide was shown to have a linear chain of β(1 → 4) linked d-mannopyranosyls units with side chains of α(1 → 6) d-galactopyranosyl units. Grafting of polyacrylamide onto the gum was performed using K2S2O8/ascorbic acid redox system in presence of Ag+ as catalyst at 35 ± 2 °C. The viscosity of the gum solution increased on grafting and the grafted gum was observed to resist biodegradation for more than 256 h. Thermogravimetric analysis revealed that grafted gum was more thermally stable than native gum. 相似文献
110.
Translocation of cell-penetrating peptides and delivery of their cargoes in triticale microspores 总被引:1,自引:0,他引:1
Microspore culture is contributing significantly in the field of plant breeding for crop improvement in general and cereals,
in particular. In the present study, we investigated the uptake of fluorescently labeled cell-penetrating peptides (CPP; Tat,
Tat2, M-Tat, peptide vascular endothelial-cadherin, transportan) in the freshly isolated triticale microspores (mid-late uninucleate
stage). We demonstrated that Tat (RKKRRQRRR) and Tat2 (RKKRRQRRRRKKRRQRRR) are able to efficiently transduce GUS enzyme (272 kDa) in its functional form in 5 and 14% of the microspores,
respectively, in a noncovalent manner. Pep-1, a synthetic CPP, was able to transduce GUS enzyme in its active form in 31%
of the microspores. The effect of various endocytic and macropinocytic inhibitors on Tat2-mediated GUS enzyme delivery was studied and revealed a preferred micropinocytosis entry. DNase I protection assay and confocal
laser microscopy was carried out to recommend a ratio of 4:1 Tat2-linear plasmid DNA (pActGUS) in complex preparation for microspore transfection. We further show that Tat2 can successfully deliver GUS gene in near to 2% triticale microspores. The negative control mutated Tat (M-Tat: AKKRRQRRR) failed to transducer the GUS
protein and transfect the GUS gene in microspore nucleus. The ability of CPPs to deliver macromolecules (protein as well as linear plasmid DNA) noncovalently
has been demonstrated in triticale isolated microspores. It further confirms potential applications of CPPs in developing
simple, time saving, cost effective plant genetic engineering technologies. 相似文献