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111.
Jawad Ullah Huayou Chen Ake Vastermark Jinru Jia Bangguo Wu Zhong Ni Yilin Le Hongcheng Wang 《World journal of microbiology & biotechnology》2017,33(9):166
Fusion protein construction often requires peptide linkers for prolonged conformation, extended stability and enzyme activity. In this study a series of fusion between Thermotoga maritima lipase Tm1350 and Bacillus subtillis coat protein CotB, comprising of several peptide linkers, with different length, flexibility and orientations were constructed. Effects of temperature, pH and chemicals were examined, on the activity of displayed enzyme. The fusion protein with longer flexible linkers L9 [(GGGGS)4] and L7 (GGGGS-GGGGS-EAAAK-EAAAK-GGGGS-GGGGS) possess 1.29 and 1.16-fold higher activity than the original, under optimum temperature and pH respectively. Moreover, spore surface displaying Tm1350 with L3 (EAAAK-GGGGS) and L9 ((GGGGS)4) showed extended thermostably, maintaining 1.40 and 1.35-fold higher activity than the original respectively, at 80 °C after 5 h of incubation. The enzyme activity of linkers with different orientation, including L5, L6 and L7 was determined, where L7 maintained 1.05 and 1.27-fold higher activity than L5 and L6. Effect of 0.1% proteinase K, bromelain, 20% ethanol and 30% methanol was investigated. Linkers with appropriate Glycine residues (flexible) showed higher activity than Alanine residues (rigid). The activity of the displayed enzyme can be improved by maintaining orientation and flexibility of peptide linkers, to evaluate high activity and stability in industrial processes. 相似文献
112.
Mohammad Fawad Ansari Faisal Hayat Afreen Inam Fatima Kathrada Robyn L. van Zyl Maureen Coetzee Kamal Ahmad Dongyun Shin Amir Azam 《Bioorganic & medicinal chemistry letters》2017,27(3):460-465
In an endeavor to develop efficacious antiprotozoal agents 4-(7-chloroquinolin-4-yl) piperazin-1-yl)pyrrolidin-2-yl)methanone derivatives (5–14) were synthesized, characterized and biologically evaluated for antiprotozoal activity. The compounds were screened in vitro against the HM1: IMSS strain of Entamoeba histolytica and NF54 chloroquine-sensitive strain of Plasmodium falciparum. Among the synthesized compounds six exhibited promising antiamoebic activity with IC50 values (0.14–1.26 μM) lower than the standard drug metronidazole (IC50 1.80 μM). All nine compounds exhibited antimalarial activity (IC50 range: 1.42–19.62 μM), while maintaining a favorable safety profile to host red blood cells. All the compounds were less effective as an antimalarial and more toxic (IC50 range: 14.67–81.24 μM) than quinine (IC50: 275.6 ± 16.46 μM) against the human kidney epithelial cells. None of the compounds exhibited any inhibitory effect on the viability of Anopheles arabiensis mosquito larvae. 相似文献
113.
Ehsan Ullah Mughal Amina Sadiq Shahzad Murtaza Hummera Rafique Muhammad Naveed Zafar Tauqeer Riaz Bilal Ahmad Khan Abdul Hameed Khalid Mohammed Khan 《Bioorganic & medicinal chemistry》2017,25(1):100-106
The present study describes efficient and facile syntheses of varyingly substituted 3-thioaurones from the corresponding 3-oxoaurones using Lawesson’s reagent and phosphorous pentasulfide. In comparison, the latter methodology was proved more convenient, giving higher yields and required short and simple methodology. The structures of synthetic compounds were unambiguously elucidated by IR, MS and NMR spectroscopy. All synthetic compounds were screened for their inhibitory potential against in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Molecular docking studies were also performed in order to examine their binding interactions with AChE and BChE human proteins. Both studies revealed that some of these compounds were found to be good inhibitors against AChE and BChE. 相似文献
114.
Ante Vujić Rüstem Hayat Ozan Demirözer Ximo Mengual Farzaneh Kazerani 《Zoology in the Middle East.》2017,63(3):250-268
New data and records of the genus Chrysotoxum Meigen, 1803 are reported, arising from taxonomic and faunistic examination of adult specimens collected from 1920 to 2011 from four northeastern provinces of Turkey (Erzurum, Bayburt, Kars, and Artvin), and from the neighboring countries of Armenia, Azerbaijan and Iran. Three new species are described: Chrysotoxum antennalis Vuji?, Nedeljkovi? &; Hayat sp. n., C. clausseni Vuji?, Nedeljkovi? &; Hayat sp. n. and C. persicum Vuji?, Nedeljkovi? &; Hayat sp. n. The first two are known only from northeastern Turkey, and the third also occurs in Armenia, Azerbaijan and Iran. These new species have in common an antenna with the basoflagellomere being shorter than the scape and pedicel together.http://www.zoobank.org/urn:lsid:zoobank.org:pub:4C264678-8E47-4DE0-AC7D-91DABC597BCD 相似文献
115.
A.?Ullah H.?Mushtaq Sh.?Fahad Hakima A.?Shah H.?J.?ChaudharyEmail author 《Microbiology》2017,86(1):119-127
Microbially unexplored medicinal plants can have a genetically diverse microbial population with multi-functional plant growth promoting traits. In this aspect, 75 endophytic bacterial isolates with plant growth promoting traits were isolated from Withania coagulans Dunal and Olea ferruginea Royal. Many of these bacteria were able to solubilize phosphate, produce indole-3-acetic acid, ammonia as well as hydrogen cyanide, synthesize extracellular enzymes and show antagonistic activities against plant pathogenic fungi under in vitro conditions. These isolates were also characterized by morphological and biochemical analysis. Furthermore, four representative isolates with pronounced plant growth promoting activities were identified as Enterobacter cloacae, Enterobacter dissolvens, Enterobacter hormaechei and Cronobacter sakazakii by 16S rDNA sequencing analysis. This work for the first time, reported the isolation of endophytic bacteria, the novel association form selected plants, Withania coagulans and Olea ferruginea. The explored endophytes might have great potential in the field of biocontrol and plant growth promoting for sustainable agricultural practices. 相似文献
116.
Cuong Quang Le Mercy Oyugi Ebenezer Joseph Toan Nguyen Md Hasmat Ullah Joshua Aubert Thien Phan Joseph Tran Kayunta Johnson-Winters 《Biochemistry and Biophysics Reports》2017
F420H2:NADP+ Oxidoreductase (Fno) catalyzes the reversible reduction of NADP+ to NADPH by transferring a hydride from the reduced F420 cofactor. Here, we have employed binding studies, steady-state and pre steady-state kinetic methods upon wtFno and isoleucine 135 (I135) Fno variants in order to study the effects of side chain length on the donor-acceptor distance between NADP+ and the F420 precursor, FO. The conserved I135 residue of Fno was converted to a valine, alanine and glycine, thereby shortening the side chain length. The steady-state kinetic analysis of wtFno and the variants showed classic Michaelis-Menten kinetics with varying FO concentrations. The data revealed a decreased kcat as side chain length decreased, with varying FO concentrations. The steady-state plots revealed non-Michaelis-Menten kinetic behavior when NADPH was varied. The double reciprocal plot of the varying NADPH concentrations displays a downward concave shape, while the NADPH binding curves gave Hill coefficients of less than 1. These data suggest that negative cooperativity occurs between the two identical monomers. The pre steady-state Abs420 versus time trace revealed biphasic kinetics, with a fast phase (hydride transfer) and a slow phase. The fast phase displayed an increased rate constant as side chain length decreased. The rate constant for the second phase, remained ~2 s?1 for each variant. Our data suggest that I135 plays a key role in sustaining the donor-acceptor distance between the two cofactors, thereby regulating the rate at which the hydride is transferred from FOH2 to NADP+. Therefore, Fno is a dynamic enzyme that regulates NADPH production. 相似文献
117.
Q. Fariduddin S. Khanam S. A. Hasan B. Ali S. Hayat A. Ahmad 《Acta Physiologiae Plantarum》2009,31(5):889-897
To investigate the effect of exogenously applied 28-homobrassinolide (HBL) on drought-stressed plants, photosynthesis and
antioxidant systems were examined in Indian mustard (Brassica juncea L.). Seedlings of Indian mustard were subjected to drought stress for 7 days at the 8–14 (DS1)/15–21 (DS2) days’ stage of
growth and then returned to normal conditions of growth. These seedlings were sprayed with HBL (0.01 μM) at the 30-day stage
and were sampled at 60 days to assess the changes in growth, photosynthesis and antioxidant enzymes. Plants exposed to stress
at either of the stages of growth exhibited a significant decrease in growth and photosynthesis. The exposure of plants to
stress at an earlier stage (DS1) was more inhibitory than that at a later stage (DS2). However, the follow-up treatment with
HBL significantly improved the values of these parameters and also overcame the inhibitory effect of water stress. The activity
of antioxidant enzymes [catalase (E.C. 1.11.1.6), peroxidase (E.C. 1.11.1.7) and superoxide dismutase (E.C. 1.15.1.1)] and
proline content in leaves exhibited an increase in response to both the treatment factors, where their interaction had an
additive effect. It was, therefore, concluded that the elevated antioxidant system, at least in part, was responsible for
amelioration of the drought stress. 相似文献
118.
The influence of sodium and potassium dynamics on excitability,seizures, and the stability of persistent states: I. Single neuron dynamics 总被引:1,自引:1,他引:0
John R. CressmanJr. Ghanim Ullah Jokubas Ziburkus Steven J. Schiff Ernest Barreto 《Journal of computational neuroscience》2009,26(2):159-170
In these companion papers, we study how the interrelated dynamics of sodium and potassium affect the excitability of neurons,
the occurrence of seizures, and the stability of persistent states of activity. In this first paper, we construct a mathematical
model consisting of a single conductance-based neuron together with intra- and extracellular ion concentration dynamics. We
formulate a reduction of this model that permits a detailed bifurcation analysis, and show that the reduced model is a reasonable
approximation of the full model. We find that competition between intrinsic neuronal currents, sodium-potassium pumps, glia,
and diffusion can produce very slow and large-amplitude oscillations in ion concentrations similar to what is seen physiologically
in seizures. Using the reduced model, we identify the dynamical mechanisms that give rise to these phenomena. These models
reveal several experimentally testable predictions. Our work emphasizes the critical role of ion concentration homeostasis
in the proper functioning of neurons, and points to important fundamental processes that may underlie pathological states
such as epilepsy.
相似文献
John R. Cressman Jr.Email: |
119.
A survey for natural entomopathogenic fungi of two spotted spider mite (Tetranychus urticae) adults was made in Erzurum, Turkey, during the period 2006. Tetranychus urticae (65.8%) infected with a strain of the fungus Cladosporium cladosporioides were found. Thirteen isolates of C.
cladosporioides were assessed against T. urticae, in a single dose (8 × 106 conidia ml −1), laboratory bioassay on bean leaflets. The total mortality percentage caused by C. cladosporioides isolates varied from 50.95 to 74.76% and LT50 values ranged from 2.34 to 3.90 days. The results revealed that isolates of C. cladosporioides were effective against two spotted spider mite. This is the first record of natural infection of T. urticae by C.
cladosporioides. 相似文献
120.