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51.
Identification of staphylococcal epsilon hemolysin 总被引:2,自引:0,他引:2
52.
Debbie C. Crans Samantha Schoeberl Ernestas Gaidamauskas Bharat Baruah Deborah A. Roess 《Journal of biological inorganic chemistry》2011,16(6):961-972
The interactions of metabolites of the antidiabetic vanadium-containing drug bis(maltolato)oxovanadium(IV) (BMOV) with lipid
interface model systems were investigated and the results were used to describe a potentially novel mechanism by which these
compounds initiate membrane-receptor-mediated signal transduction. Specifically, spectroscopic studies probed the BMOV oxidation
and hydrolysis product interaction with interfaces created from cetyltrimethylammonium bromide (CTAB) which mimics the positively
charged head group on phosphatidylcholine. 1H and 51V NMR spectroscopies were used to determine the location of the dioxobis(maltolato)oxovanadate(V) and the maltol ligand in
micelles and reverse micelles by measuring changes in the chemical shift, signal linewidth, and species distribution. Both
micelles and reverse micelles interacted similarly with the complex and the ligand, suggesting that interaction is strong
as anticipated by Coulombic attraction between the positively charged lipid head group and the negatively charged complex
and deprotonated ligand. The nature of the model system was confirmed using dynamic light scattering studies and conductivity
measurements. Interactions of the complex/ligand above and below the critical micelle concentration of micelle formation were
different, with much stronger interactions when CTAB was in the form of a micelle. Both the complex and the ligand penetrated
the lipid interface and were located near the charged head group. These studies demonstrate that a lipid-like interface affects
the stability of the complex and raise the possibility that ligand exchange at the interface may be important for the mode
of action for these systems. Combined, these studies support recently reported in vivo observations of BMOV penetration into
3T3-L1 adipocyte membranes and increased translocation of a glucose transporter to the plasma membrane. 相似文献
53.
Foraging behavior is influenced by spatial and temporal habitat heterogeniety. Here we report on within-day foraging and perceived risk of predation by the striped mouse (Rhabdomys pumilio) in a grassland savannah with wooded “islands” using giving-up densities (GUD, amount of food left behind in depletable food patches). Higher GUDs correspond to higher forging costs. GUDs were measured six times per day at 2-h intervals from paired stations along fern–grass habitat boundaries at 3 and 6 m distances from 10 wooded islands. R. pumilio's GUDs varied significantly over the course of the day with highest GUDs during the afternoon hours of 1–3 pm, and lowest between 7 and 9 am in the morning. The same pattern was consistent for both habitats (fern and grass) and distances from the wooded islands. GUDs decreased with distance from the woody islands in both fern and grass habitats and were significantly lower in the fern habitat. This activity pattern suggests that R. pumilio responds to a spectrum of spatially and temporally varying risks from a variety of predators including aerial predators that increase risk as they make use of mid-day thermals. 相似文献
54.
Nur Fariza Abd. RahmanMahiran Basri Mohd Basyaruddin Abdul RahmanRaja Noor Zaliha Raja Abdul Rahman Abu Bakar Salleh 《Bioresource technology》2011,102(3):2168-2176
Engkabang fat esters were produced via alcoholysis reaction between Engkabang fat and oleyl alcohol, catalyzed by Lipozyme RM IM. The reaction was carried out in a 500 ml Stirred tank reactor using heptane and hexane as solvents. Response surface methodology (RSM) based on a four-factor-five-level Central composite design (CCD) was applied to evaluate the effects of synthesis parameters, namely temperature, substrate molar ratio (oleyl alcohol: Engkabang fat), enzyme amount and impeller speed. The optimum yields of 96.2% and 91.4% were obtained for heptane and hexane at the optimum temperature of 53.9 °C, impeller speeds of 309.5 and 309.0 rpm, enzyme amounts of 4.82 and 5.65 g and substrate molar ratios of 2.94 and 3.39:1, respectively. The actual yields obtained compared well with the predicted values of 100.0% and 91.5%, respectively. Meanwhile, the properties of the esters show that they are suitable to be used as ingredient for cosmetic applications. 相似文献
55.
Md Robiul Karim Farzana Islam Rume Abu Nasar Md Aminoor Rahman Zhenjie Zhang Junqiang Li Longxian Zhang 《The Journal of eukaryotic microbiology》2020,67(4):427-435
To determine the occurrence and genotypes of Enterocytozoon bieneusi in captive mammals at Bangladesh National Zoo and to assess their zoonotic significance, 200 fecal samples from 32 mammalian species were examined using a nested PCR and sequencing of internal transcribed spacer (ITS) gene. Enterocytozoon bieneusi was detected in 16.5% (33/200) of the samples. Seven different ITS genotypes were identified, including two known genotypes (D and J) and five new ones (BAN4 to BAN8). Genotype D was the most common genotype being observed in 19 isolates. In phylogenetic analysis, four genotypes (D, BAN4, BAN5, and BAN6), detected in 30 isolates (90.9%), belonged to Group 1 having zoonotic potential. The sequence of genotype J found in a Malayan pangolin was clustered in so‐called ruminant‐specific Group 2. The other two genotypes BAN7 and BAN8 were clustered in primate‐specific Group 5. To our knowledge, this is the first report of molecular characterization of E. bieneusi in Bangladesh, particularly in captive‐bred wildlife in this country. The potentially zoonotic genotypes of E. bieneusi are maintained in zoo mammals that may transmit among these animals and to the humans through environmental contamination or contact. 相似文献
56.
57.
Wali Ahmidin Wubulikasimu Atikan yanhua Gao Omar Adil Arken Amina Yili Abulimiti Aisa Haji Akber 《International journal of peptide research and therapeutics》2020,26(4):1803-1818
International Journal of Peptide Research and Therapeutics - The purpose of this study was to separate and purify antioxidant peptides from the scorpion (Buthus martensii Karsch) protein... 相似文献
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60.
Mohammad Badrul Anam Shah Adil Ishtiyaq Ahmad Mikiko Kudo Arif Istiaq Athary Abdulhaleem M. Felemban Naofumi Ito Kunimasa Ohta 《Development, growth & differentiation》2020,62(2):97-107
Specialized microenvironment, or neurogenic niche, in embryonic and postnatal mouse brain plays critical roles during neurogenesis throughout adulthood. The subventricular zone (SVZ) and the dentate gyrus (DG) of hippocampus in the mouse brain are two major neurogenic niches where neurogenesis is directed by numerous regulatory factors. Now, we report Akhirin (AKH), a stem cell maintenance factor in mouse spinal cord, plays a pivotal regulatory role in the SVZ and in the DG. AKH showed specific distribution during development in embryonic and postnatal neurogenic niches. Loss of AKH led to abnormal development of the ventricular zone and the DG along with reduction of cellular proliferation in both regions. In AKH knockout mice (AKH−/−), quiescent neural stem cells (NSCs) increased, while proliferative NSCs or neural progenitor cells decreased at both neurogenic niches. In vitro NSC culture assay showed increased number of neurospheres and reduced neurogenesis in AKH−/−. These results indicate that AKH, at the neurogenic niche, exerts dynamic regulatory role on NSC self-renewal, proliferation and differentiation during SVZ and hippocampal neurogenesis. 相似文献