共查询到20条相似文献,搜索用时 31 毫秒
1.
Photodynamic treatment by the cationic TMPyP photosensitizer was undertaken on the multiple antibiotic-resistant bacteria
Acinetobacter baumannii and Escherichia coli. Total eradication of the bacterial cultures was determined immediately after initiation of illumination when these bacteria
were treated with 5, 10, 15, 20-tetra (4-N methylpyridyl)porphine (TMPyP) at a concentration of 29.4 μmol/L and illuminated
by blue, green, or red light. Total eradication of both bacteria was obtained also after treatment of bacterial cultures with
3.7 μmol/L TMPyP and illumination with blue light (400–450 nm). On the other hand, an 8- or 16- to 20-fold higher light intensity,
respectively, was required for total eradication upon illumination with green (480–550 nm) or red light (600–700 nm). A 407-nm
blue light only 7 and 9 joules/cm2, respectively, was needed for total eradication of both bacteria even at a concentration of 3.7 μmol/L TMPyP. X-ray-linked
microanalysis demonstrated loss of potassium and a flood of sodium and chloride into the cells, indicating serious damage
to the cytoplasmic membrane. Transmission electron microscopy (TEM) revealed structural changes and damage to the membrane
of treated E. coli. In A. baumannii-treated cells, mesosomes and black dots that resemble aggregation of polyphosphate polymers could be seen. DNA breakage appeared
only after a long period of illumination, when the bacterial cell was no longer viable. It can be concluded that cytoplasmic
membrane damage and not DNA breakage is the major cause for bacterial death upon photosensitization.
Received: 13 October 2000 / Accepted: 17 November 2000 相似文献
2.
Jaclyn Hosmer Rachel Reed M. Vitória L.B. Bentley Adwoa Nornoo Luciana B. Lopes 《AAPS PharmSciTech》2009,10(2):589-596
We evaluated the ability of microemulsions containing medium-chain glycerides as penetration enhancers to increase the transdermal
delivery of lipophilic (progesterone) and hydrophilic (adenosine) model drugs as well as the effects of an increase in surfactant
blend concentration on drug transdermal delivery. Microemulsions composed of polysorbate 80, medium-chain glycerides, and
propylene glycol (1:1:1, w/w/w) as surfactant blend, myvacet oil as the oily phase, and water were developed. Two microemulsions containing different concentrations
of surfactant blend but similar water/oil ratios were chosen; ME-lo contained a smaller concentration of surfactant than ME-hi
(47:20:33 and 63:14:23 surfactant/oil/water, w/w/w). Although in vitro progesterone and adenosine release from ME-lo and ME-hi was similar, their transdermal delivery was differently affected.
ME-lo significantly increased the flux of progesterone and adenosine delivered across porcine ear skin (4-fold or higher,
p < 0.05) compared to progesterone solution in oil (0.05 ± 0.01 μg/cm2/h) or adenosine in water (no drug was detected in the receptor phase). The transdermal flux of adenosine, but not of progesterone,
was further increased (2-fold) by ME-hi, suggesting that increases in surfactant concentration represent an interesting strategy
to enhance transdermal delivery of hydrophilic, but not of lipophilic, compounds. The relative safety of the microemulsions
was assessed in cultured fibroblasts. The cytotoxicity of ME-lo and ME-hi was significantly smaller than sodium lauryl sulfate
(considered moderate-to-severe irritant) at same concentrations (up to 50 μg/mL), but similar to propylene glycol (regarded
as safe), suggesting the safety of these formulations. 相似文献
3.
Cultures able to dechlorinate cis-1,2-dichloroethene (cDCE) were selected with ethene (3–20%, v/v) as the sole source of carbon and energy. One mixed culture (K20) could degrade
cDCE (400 μmol l–1) or vinyl chloride (100 μmol l–1) in the presence of ethene (≤ 80 μmol l–1 and ≤ 210 μmol l–1, respectively). This culture consists of at least five bacterial strains. All five strains were able to degrade cDCE cometabolically in pure culture. The mixed culture K20 was highly tolerant against cDCE (up to 6 mmol l–1 in the liquid phase). Degradation of cDCE (200 μmol l–1) was not affected by the presence of trichloroethene (100 μmol l–1) or tetrachloroethene (100 μmol l–1). Transformation yields (Ty, defined as unit mass of chloroethene degraded per unit mass of ethene consumed) of the mixed culture K20 were relatively
high (0.51 and 0.61 for cDCE and vinyl chloride, respectively). The yield for cDCE with ethene as auxiliary substrate was ninefold higher than any values reported with methane or methane/formate as auxiliary
substrate. The viability of the cells of the mixed culture K20 (0.3 mg of cells ml–1) was unaffected by the transformation of ≤ 200 μmol l–1
cDCE in 300 min.
Received: 9 March 1999 / Accepted: 21 July 1999 相似文献
4.
Ling Ding Xi Li Peng Liu Shiqian Li Jiliang Lv 《Biological trace element research》2010,137(3):364-372
The biological effect of Se and Cu2+ on Escherichia coli (E. coli) growth was studied by using a 3114/3236 TAM Air Isothermal Calorimeter, ampoule method, at 37°C. From the thermogenesis
curves, the thermokinetic equations were established under different conditions. The kinetics showed that a low concentration
of Se (1–10 μg/mL) promoted the growth of E. coli, and a high concentration of Se (>10 μg/mL) inhibited the growth, but the Cu2+ was always inhibiting the growth of E. coli. Moreover, there was an antagonistic or positive synergistic effect of Se and Cu2+ on E. coli in the different culture medium when Se was 1–10 μg/ml and Cu2+ was 1–20 μg/ml. There was a negative synergistic effect of Se and Cu2+ on E. coli when Se was higher than 10 μg/ml and Cu2+ was higher than 20 μg/ml. The antagonistic or synergistic effect between Se and Cu2+ on E. coli was related to the formation of Cu–Se complexes under the different experimental conditions chosen. 相似文献
5.
Federica Villa Lucia Giacomucci Andrea Polo Pamela Principi Lucia Toniolo Marienella Levi Stefano Turri Francesca Cappitelli 《Biotechnology letters》2009,31(9):1407-1413
The potential on N-vanillylnonanamide (NVN) in preventing the attachment of Pseudomonas stutzeri and a Bacillus cereus-group strain was investigated. NVN up to 852 μM was not toxic, nor was it an energy source for either organism. Microbial
attachment assays were carried out on glass and polylysine slides. with NVN being dispersed in or applied to the surfaces
using a polyurethane coating. NVN at 205 μM inhibited Bacillus adhesion on glass slides by 48% and the percentage did not significantly increase at 852 μM. NVN blended into or sprayed
onto the coating at 205 μmol/kg did not prevent adhesion. The compound is therefore not useful as an antifouling product under
the tested coating conditions. 相似文献
6.
Ganka Chaneva Sevdalina Furnadzhieva Kaledona Minkova Jaromir Lukavsky 《Journal of applied phycology》2007,19(5):537-544
The effect of light intensity (50–300 μmol photons m−2 s−1) and temperature (15–50°C) on chlorophyll a, carotenoid and phycobiliprotein content in Arthronema africanum biomass was studied. Maximum growth rate was measured at 300 μmol photons m−2 s−1 and 36°C after 96 h of cultivation. The chlorophyll a content increased along with the increase in light intensity and temperature and reached 2.4% of dry weight at 150 μmol photons
m−2 s−1 and 36°C, but it decreased at higher temperatures. The level of carotenoids did not change significantly under temperature
changes at illumination of 50 and 100 μmol photons m−2 s−1. Carotenoids were about 1% of the dry weight at higher light intensities: 150 and 300 μmol photons m−2 s−1. Arthronema africanum contained C-phycocyanin and allophycocyanin but no phycoerythrin. The total phycobiliprotein content was extremely high,
more than 30% of the dry algal biomass, thus the cyanobacterium could be deemed an alternative producer of C-phycocyanin.
A highest total of phycobiliproteins was reached at light intensity of 150 μmol photons m−2 s−1 and temperature of 36°C, C-phycocyanin and allophycocyanin amounting, respectively, to 23% and 12% of the dry algal biomass.
Extremely low (<15°C) and high temperatures (>47°C) decreased phycobiliprotein content regardless of light intensity. 相似文献
7.
The toxicity of cadmium to barley plants as affected by complex formation with humic acid 总被引:3,自引:0,他引:3
An ‘alternating solution’ culture method was used to study the effects of chloride ions and humic acid (HA) on the uptake
of cadmium by barley plants. The plants were transferred periodically between a nutrient solution and a test solution containing
one of four levels of HA (0, 190, 569 or 1710 μg cm−3) and one of five levels of Cd (0, 0.5, 1.0, 2.5 or 5.0 μg cm−3) in either a 0.006M NaNO3 or 0.006M NaCl medium. Harvest and analysis of shoots and roots was after nineteen days. The distribution of Cd in the test solutions
between Cd2+, CdCl+ and HA-Cd was determined in a separate experiment by dialysis equilibrium.
In the nitrate test solutions Cd uptake was clearly controlled by Cd2+ concentration and was therefore reduced by HA complex formation. In the absence of HA, chloride suppressed Cd uptake indicating
that Cd2+ was the preferred species. However complex formation with Cl− enhanced uptake when HA was present because of an increase in the concentration of inorganic Cd species relative to the nitrate
system.
The ratio root-Cd/shoot-Cd remained at about 10 across a wide range of shoot-Cd concentrations, from about 3 μg g−1 (sub-toxic) up to 85 μg g−1 (80% yield reduction). The ability of the barley plants to accumulate ‘non-toxic’ Cd in their roots was thus very limited.
Humic acid also had no effect on Cd translocation within the plant and the root/shoot weight ratio did not vary with any treatment.
At shoot-Cd concentrations in excess of 50 μg g−1, K, Ca, Cu and Zn uptake was reduced, probably the result of root damage rather than a specific ion antagonism. The highest
concentration of HA also lowered Fe and Zn uptake and there was a toxic effect with increasing HA concentration at Cd=0. However
the lowest HA level, comparable with concentrations found in mineral soil solutions, only reduced yield (in the absence of
Cd) by <5% while lowering Cd uptake across the range of Cd concentrations by 66%–25%. 相似文献
8.
Wen-Ru Li Xiao-Bao Xie Qing-Shan Shi Hai-Yan Zeng You-Sheng OU-Yang Yi-Ben Chen 《Applied microbiology and biotechnology》2010,85(4):1115-1122
The antibacterial activity and acting mechanism of silver nanoparticles (SNPs) on Escherichia coli ATCC 8739 were investigated in this study by analyzing the growth, permeability, and morphology of the bacterial cells following
treatment with SNPs. The experimental results indicated 10 μg/ml SNPs could completely inhibit the growth of 107 cfu/ml E. coli cells in liquid Mueller–Hinton medium. Meanwhile, SNPs resulted in the leakage of reducing sugars and proteins and induced
the respiratory chain dehydrogenases into inactive state, suggesting that SNPs were able to destroy the permeability of the
bacterial membranes. When the cells of E. coli were exposed to 50 μg/ml SNPs, many pits and gaps were observed in bacterial cells by transmission electron microscopy and
scanning electron microscopy, and the cell membrane was fragmentary, indicating the bacterial cells were damaged severely.
After being exposed to 10 μg/ml SNPs, the membrane vesicles were dissolved and dispersed, and their membrane components became
disorganized and scattered from their original ordered and close arrangement based on TEM observation. In conclusion, the
combined results suggested that SNPs may damage the structure of bacterial cell membrane and depress the activity of some
membranous enzymes, which cause E. coli bacteria to die eventually. 相似文献
9.
Tsuneo Kaneshiro Jack W. Newton Edward Selke Morey E. Slodki 《Current microbiology》1980,3(5):279-281
Dinitrogen (15N2) fixation of four free-livingRhizobium strains ranged from 0.8 to 2.3 μmol/mg biomass N. Parallel-grown cultures liberated 4–8 μmol hydrogen and reduced 12–23 μmol
acetylene, giving a mean ratio of reduced acetylene-to-fixed15N2 of 12. This ratio contrasts with lower values others have observed for asymbiotic diazotrophs. 相似文献
10.
Camille L. Hyde Gregory C. Phillips 《In vitro cellular & developmental biology. Plant》1996,32(2):72-80
Summary Chile pepper (Capsicum annuum L.) plants were regenerated from cotyledon explantsin vitro in four major stages: bud induction, bud enlargement, shoot elongation, and root development. Bud induction medium contained
0.5 mg/L (2.9μM) indole-3-acetic acid and 2 mg/L (8.9 μM) N6-benzyladenine. Bud enlargement occurred, and an occasional shoot appeared when medium with 2 mg/L (6μM) gibberellic acid, 2 mg/L (8.9 μM) N6-benzyladenine, and 5 mg/L (29.4 μM) silver nitrate was used. Most shoots elongated after placement on a third medium without plant growth regulators or on fresh
plates of bud enlargement medium. Incubations were for 2, 2, and 4 weeks, respectively, at 28.5°C and continuous light. Treatment
with silver nitrate was necessary for multiple shoot production and elongation to occur in the third culture stage and was
most effective when present in the second-stage medium but not in the bud induction medium. Sixteen to 26% of the shoots rooted
in medium with 1 mg/L (5.4 μM) 1-naphthaleneacetic acid after 1 month. Additional shoots transferred to a second rooting medium with 0.1 or 1.0 mg/L (0.54
or 5.4 μM) 1-naphthaleneacetic acid developed roots, increasing the overall rooting efficiency to 70–72%. Most rooted shoots grew well
and produced viable seeds when grown in the greenhouse. Other cytokinins tested for plant regeneration were zeatin and thidiazuron.
Zeatin induced few shoots and fewer well-developed plants. Thidiazuron induced multiple shoots 4 months after culture began,
but many were small and did not elongate further. Phytagar tissue culture grade proved superior to other agars tested, increasing
bud induction frequency from 0-33% to 80–93% and eliminating explant hyperhydricity. 相似文献
11.
Efficacy of silver thiosulfate (STS) in reducing ethylene-induced culture abnormalities during minimal growth conservation
of microplants was studied in seven potato (Solanum tuberosum L.) genotypes. Different concentrations of STS (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 μg ml–1) were tested in minimal growth medium based on MS medium supplemented with 20 g l–1 mannitol and 40 g l–1 sucrose. STS improved the microplant growth and reduced the culture abnormalities during prolonged maintenance of potato
shoot cultures in vitro. The beneficial effect of STS was most prominent for number of green leaves per microplant and leaf
senescence. After 16 months of storage, desirable microplant growth was observed in cultures conserved in medium containing
6.0–9.0 μg ml–1 STS. The profile of the peroxidase isozymes of conserved cultures did not show any apparent genetic variation due to the
presence of STS in the conservation medium.
Received: 2 September 1998 / Revision received: 20 November 1998 / Accepted: 12 December 1998 相似文献
12.
Chlorophyll-a (chl-a) and carotenoid pigments of the zooxanthellate octocoral Sinularia flexibilis were analyzed using high performance liquid chromatography following exposure to three light intensities for over 30 days.
From the coral fragments located at different light intensities, a total carotenoid of >41 μg g−1 dry weight, including peridinin, xanthophylls (likely diadinoxanthin + diatoxanthin), and chl-a as the most abundant pigments, with minor contents of astaxantin and β-carotene were detected. The whole content of chl-a weighed 5 μg g−1 dry weight in all coral colonies. Chl-a and carotenoids contributed 11.2% and 88.2%, respectively, to all pigments detected, and together accounted for 99.4% of
the total pigments present. The highest contents of carotenoids and chl-a was observed in the coral grafts placed in an irradiance of 100 μmol quanta m−2 s−1; they showed lower ratios of total carotenoids: chl-a compared to those exposed to 400 μmol quanta m−2 s−1 after >30 days of incubation. The ratios of peridinin and xanthophylls with respect to chl-a from the colonies at 400 μmol quanta m−2 s−1 were approximately double those observed at irradiances of 100 and 200 μmol quanta m−2 s−1. Partial quantification of pigments in this study showed that the carotenoids of S. flexibilis showed a decrease at irradiances above 100 μmol quanta m−2 s−1, with the exception of an increase in β-carotene at 200 μmol quanta m−2 s−1. 相似文献
13.
Raghu G Balaji V Venkateswaran G Rodrigue A Maruthi Mohan P 《Applied microbiology and biotechnology》2008,81(3):571-578
Removal of radioactive cobalt at trace levels (≈nM) in the presence of large excess (106-fold) of corrosion product ions of complexed Fe, Cr, and Ni in spent chemical decontamination formulations (simulated effluent)
of nuclear reactors is currently done by using synthetic organic ion exchangers. A large volume of solid waste is generated
due to the nonspecific nature of ion sorption. Our earlier work using various fungi and bacteria, with the aim of nuclear
waste volume reduction, realized up to 30% of Co removal with specific capacities calculated up to 1 μg/g in 6–24 h. In the
present study using engineered Escherichia coli expressing NiCoT genes from Rhodopseudomonas palustris CGA009 (RP) and Novosphingobium aromaticivorans F-199 (NA), we report a significant increase in the specific capacity for Co removal (12 μg/g) in 1-h exposure to simulated effluent.
About 85% of Co removal was achieved in a two-cycle treatment with the cloned bacteria. Expression of NiCoT genes in the E. coli knockout mutant of NiCoT efflux gene (rcnA) was more efficient as compared to expression in wild-type E. coli MC4100, JM109 and BL21 (DE3) hosts. The viability of the E. coli strains in the formulation as well as at different doses of gamma rays exposure and the effect of gamma dose on their cobalt
removal capacity are determined. The potential application scheme of the above process of bioremediation of cobalt from nuclear
power reactor chemical decontamination effluents is discussed. 相似文献
14.
Summary
In vitro propagation of Quassia amara L. (Simaroubaceae) was attempted using mature and juvenile explants. Attempts to establish in vitro culture using leaf and internode explants from a plant more than 15yr old were unsuccessful due to severe phenolic exudation.
Plant regeneration through direct and indirect somatic embryogenesis was established from cotyledon explants. Murashige and
Skoog (MS) medium with 8.9 μM N6-benzyladenine (BA) and 11.7 μM silver nitrate induced the highest number (mean of 32.4 embryos per cotyledon) of somatic embryos. Direct somatic embryogenesis
as well as callus formation was observed on medium with BA (8.9–13.3 μM). Semi-mature pale green cotyledons were superior for the induction of somatic embryos. Embryos developed from the adaxial
side as well as from the point of excision of the embryonic axis. More embryos were developed on the proximal end compared
to mid and distal regions of the cotyledons. Subculture of callus (developed along with the somatic embryos on medium with
BA alone) onto medium containing 8.9 μM BA and 11.7 μM silver nitrate produced a mean of 17.1 somatic embryos. Primary somatic embryos cultured on MS medium with 8.9 μM BA and 11.7μM silver nitrate produced a mean of 9.4 secondary somatic embryos. Most of the embryos developed up to early cotyledonary stage.
Reduced concentration of BA (2.2 or 4.4 μM) improved maturation and conversion of embryos to plantlets. Ninety percent of the embryos converted to plantlets. The optimized
protocol facilitated recovery of 30 plantlets per cotyledon explant within 80d. Plantlets transferred to small cups were subsequently
transferred to field conditions with a survival rate of 90%. 相似文献
15.
Mohammad K. Khalesi H. H. Beeftink R. H. Wijffels 《Marine biotechnology (New York, N.Y.)》2009,11(4):488-494
The branching zooxanthellate soft coral Sinularia flexibillis releases antimicrobial and toxic compounds with potential pharmaceutical importance. As photosynthesis by the symbiotic algae
is vital to the host, the light-dependency of the coral, including its specific growth rate (μ day−1) and the physiological response to a range of light intensities (10–1,000 μmol quanta m−2 s−1) was studied for 12 weeks. Although a range of irradiances from 100 to 400 μmol quanta m−2 s−1 was favorable for S. flexibilis, based on chlorophyll content, a light intensity around 100 μmol quanta m−2 s−1 was found to be optimal. The contents of both zooxanthellae and chlorophyll a were highest at 100 μmol quanta m−2 s−1. The specific budding rate showed almost the same pattern as the specific growth rate. The concentration of the terpene flexibilide,
produced by this species, increased at high light intensities (200–600 μmol quanta m−2 s−1). 相似文献
16.
Present study aims at estimation and validation of net primary productivity (NPP) using production efficiency model (PEM),
and its possible relationship with tree diversity. The PEM estimates NPP, based on light use efficiency (LUE) and intercepted
photosynthetically active radiation (IPAR). Weighted average LUE varied between 0.02 gC/μmol/m2 of PAR (Mixed forest (miscellaneous)) to 0.08 gC/μmol/m2 of PAR (Acacia forest), in growing phase (GP), and 0.0008 gC/μmol/m2 of PAR (Boswellia mixed forest) to 0.023 gC/μmol/m2 of PAR (Acacia forest) during the senescent phase (SP). The average weighted LUE for tropical dry and Moist deciduous forest (MDF) in GP
were 0.05 gC/μmol/m2 of PAR and 0.03 gC/μmol/m2 of PAR, respectively. The average IPAR for different forest types was 2079.58 μmol/m2/s during GP and 1510.58 μmol/m2/s during SP. The PEM based NPP varied between 0.58–275.78 gC/m2/year during GP and 0.43–74.34 gC/m2/year during SP. The PEM based NPP and conventional (ground based) NPP were related with R
2 of 0.55. The tree diversity and NPP relationship was observed with R
2 of 0.55 at the level of both plot and forest types. 相似文献
17.
Vinod Kumar A Ramakrishna G A Ravishankar 《In vitro cellular & developmental biology. Plant》2007,43(6):602-607
The effect of cobalt chloride, salicylic acid, and silver nitrate for embryogenesis was studied in in vitro cultures of Coffea canephora. Murashige and Skoog (in Physiol. Plant. 15:473–497, 1962) medium containing 20 and 40 μM either of cobalt chloride, silver
nitrate, or salicylic acid supplemented with 1.1 μM N
6 benzyladenine and 2.85 μM indole-3-acetic acid was used for the study. At 20 and 40 μM silver nitrate treatment, 35–48% explants
responded for embryogenesis, and 38 ± 7 and 153 ± 27 embryos were produced from each callus mass, respectively, whereas only
5% control explants responded on medium devoid of silver nitrate, cobalt chloride, or salicylic acid. Secondary embryogenesis
was observed in 70–90% of the explants, and around 100–150 embryos were produced from each explant cultured on a medium containing
silver nitrate, and only a 3% response was noticed in control embryo explants. Yellow friable embryogenic calluses were obtained
from the cut edges of most of the tissues grown in a medium supplemented with cobalt chloride. The results clearly demonstrated
that, among the tested ethylene inhibitors, silver nitrate is very effective in reprogramming the cellular machinery toward
embryogenesis. 相似文献
18.
T. P. Pirog T. A. Shevchuk Yu. A. Klimenko 《Applied Biochemistry and Microbiology》2010,46(6):599-606
Activity of key enzymes of n-alkane metabolism was determined in cells of Rhodococcus erythropolis EK-1, a surfactant producer grown on n-hexadecane. Potassium cations were found to inhibit alkane hydroxylase and NADP+-dependent aldehyde dehydrogenase, while sodium cations were found to activate these enzymes. Decreased potassium concentration
(to 1 mM), increased sodium concentration (to 35 mM), and addition of 36 μmol/l Fe(II), required for alkane hydroxylase activity,
resulted in increased activity of the enzymes of n-hexadecane metabolism and in a fourfold increase of surfactant synthesis. A 1.5–1.7-fold increase in surfactant concentration
after addition of 0.2% fumarate (gluconeogenesis precursor) and 0.1% citrate (lipid synthesis regulator) to the medium with
n-hexadecane results from enhanced synthesis of trehalose mycolates, as evidenced by a 3–5-fold increase in phosphoenolpyruvate
synthetase and trehalose phosphate synthase, respectively. 相似文献
19.
Xixia Liu Hong Wang Yan Liang Jinyi Yang Hongbin Zhang Hongtao Lei Yudong Shen Yuanming Sun 《Molecular biotechnology》2010,45(1):56-64
The production and characterization of an anti-clenbuterol single-chain Fv antibody (CBLscFv)–bacterial alkaline phosphatase
(AP) fusion protein are described. The CBLscFv and the phoA gene of Escherichia coli strain K12 chromosomal DNA were cloned by PCR and sequentially inserted into the expression vector pBV220 to express the
CBLscFv–AP fusion protein in E. coli strain BL21(DE3)pLysS. SDS–PAGE and western blot analyses revealed that the fusion protein showed a molecular weight of 73 kDa
and bound with the antibacterial AP monoclonal antibody. Determination of enzymatic activity indicated that k
cat and K
m values of the fusion protein were 113.60 s−1 and 29.82 μM, respectively. Competitive direct enzyme-linked immunosorbent assay based on the obtained fusion protein indicated
that the average concentration required for 50% inhibition of binding (IC50) and the limit of detection for CBL were 4.74 ± 0.003 (n = 3) and 0.54 ± 0.004 (n = 3) μg/l, respectively, and the linear response range extended from 1.13 to 69.68 μg/l. Cross-reactivity studies showed
that the fusion protein did not cross-react with CBL analogs. The present findings indicate that the production of the CBLscFv–AP
fusion protein in E. coli strain BL21(DE3)pLysS is feasible and suggest that it could be further used to develop a one-step ELISA for the specific
detection of CBL. 相似文献
20.
In this work, an over-expressed cyclobutane pyrimidine dimer (CPD) photolyase of Synechococcus sp. PCC 7942 was used to investigate UV-C (ultraviolet irradiation of C-region) influence on photoreactivation. In vivo photoreactivation experiments indicated that the survival rate decreased from 100 to 2.6% when the UV-C flux was increased
from 1.1 to 68.5 μW/cm2. It seemed that the photolyase was easily inactivated at UV-C intensities ≥25.5 μW/cm2. Spectrometric analysis indicated that tertiary structure of the photolyase changed evidently when the UV-C fluxes were ≥25.5
μW/cm2, while the secondary structure was almost unchanged even at 170 μW/cm2. Band shift assay indicated that catalytic activity of the photolyase was impaired at fluxes ≥25.5 μW/cm2, but no significant influence on DNA-binding activity was observed. These results suggest that photoreactivation is efficient
at UV-C fluxes ≤25.5 μW/cm2, but would be impaired by intense UV-C irradiation due to structure changes of the photolyase.
Published in Russian in Biokhimiya, 2007, Vol. 72, No. 5, pp. 668–673. 相似文献