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111.
Shamsipur M Miran Beigi AA Teymouri M Poursaberi T Mostafavi SM Soleimani P Chitsazian F Tash SA 《Biodegradation》2012,23(2):311-318
Methyl tert-butyl ether (MTBE) is widely used as gasoline oxygenate and octane number enhancer for more complete combustion
in order to reduce the air pollution caused by motor vehicle exhaust. The possible adverse effects of MTBE on human health
are of major public concern. However, information on the metabolism of MTBE in human tissues is scarce. The present study
demonstrates that human cytochrome P450 2A6 is able to metabolize MTBE to tert-butyl alcohol (TBA), a major circulating metabolite
and marker for exposure to MTBE. As CYP2A6 is known to be constitutively expressed in human livers, we infer that it may play
a significant role in metabolism of gasoline ethers in liver tissue. 相似文献
112.
Neda Soltani Ramezan Ali Khavari-Nejad Mojtaba Tabatabaei Yazdi Shadman Shokravi Eduardo Fernández-Valiente 《World journal of microbiology & biotechnology》2006,22(6):571-576
Summary Our objective was to evaluate the physiological response of Fischerella ambigua FS18 to the combined influence of pH (5, 7 and 9) and light intensity (3 and 300 μmol photon m−2 s−1). Growth rates were similar at pH 9 and pH 7. There was no growth at pH 5. Increasing light intensity did not have any considerable
influence on growth rates. Chlorophyll concentration was higher at pH 7 at all light intensities. Chlorophyll concentration
decreased with increasing light intensity from 3 to 300 μmol photon m−2 s−1. Synthesis of the phycobiliproteins (PBP), phycocyanin (PC) and allophycocyanin (APC) had the highest rate in pH 7. Increasing
irradiance decreased the concentrations of all PBPs. The light-saturated photosynthetic rate was clearly higher at high light
intensity. With respect to nitrogenase activity, the highest rate was at pH 9 and 300 μmol photon m−2 s−1. Irradiance did not affect significantly this activity at pH 7. This cyanobacterium seems to be alkalophilic with maximum
nitrogenase activity and photosynthesis at pH 9. It can also adapt its photosynthetic apparatus to the variable factors that
are found in rice fields. 相似文献
113.
Abolghasem Tohidpour Shahin Najar Peerayeh Jalil F. Mehrabadi Hadi Rezaei Yazdi 《Current microbiology》2009,59(3):352-355
In Gram negative bacteria, fluoroquinolone resistance is acquired by target mutations in topoisomerase genes or by reducing
the permeation of drugs due to the increase in expression of endogenous multidrug efflux pumps that expel structurally unrelated
antimicrobial agents. An ongoing challenge is searching for new inhibitory substances in order to block efflux pumps and restore
the antibiotic drugs susceptibility. In this research, we sought to investigate the interplay between ciprofloxacin and an
efflux pump inhibitor (EPI), phenyl alanine arginyl β-naphtylamide (PAβN), to determine the prevalence of efflux pump overexpression
in clinical isolates of Pseudomonas aeruginosa. Ciprofloxacin was tested at different concentrations (256–0.25 μg/ml) with a fixed concentration of PAβN (50 μg/ml). The
isolates susceptibility profiles were analyzed by disc diffusion and agar dilution methods using 10 antibiotic discs and 4
powders. It was found that in the presence of PAβN, resistance to ciprofloxacin was inhibited obviously and MIC values were
decreased. The comparison between subgroups of P. aeruginosa isolates with different resistance profiles indicates that efflux pump overexpression (EPO) is present in 35% of ciprofloxacin
resistant isolates with no cross resistance and in variable frequencies among isolates showing cross resistance to other tested
antibiotics: gentamicin (31%), ceftazidime (29%), and imipenem (18%). Altogether, these results imply that PAβN maybe effective
to restore the fluoroquinolone drugs susceptibility in clinical treatment procedures. Results also show that increased use
of a fluoroquinolone drug such as ciprofloxacin can affect the susceptibility of P. aeruginosa to other different antipseudomonal agents. 相似文献
114.
Background
Selection schemes aiming at introgressing genetic material from a donor into a recipient line may be performed by backcross-breeding programs combined with selection to preserve the favourable characteristics of the donor population. This stochastic simulation study investigated whether genomic selection can be effective in preserving a major quantitative trait locus (QTL) allele from a donor line during the backcrossing phase.Methods
In a simulation study, two fish populations were generated: a recipient line selected for a production trait and a donor line characterized by an enhanced level of disease resistance. Both traits were polygenic, but one major QTL affecting disease resistance was segregating only within the donor line. Backcrossing was combined with three types of selection (for total merit index) among the crossbred individuals: classical selection, genomic selection using genome-wide dense marker maps, and gene-assisted genomic selection. It was assumed that production could be observed directly on the selection candidates, while disease resistance had to be inferred from tested sibs of the selection candidates.Results
Classical selection was inefficient in preserving the target QTL through the backcrossing phase. In contrast, genomic selection (without specific knowledge of the target QTL) was usually effective in preserving the target QTL, and had higher genetic response to selection, especially for disease resistance. Compared with pure genomic selection, gene-assisted selection had an advantage with respect to disease resistance (28–40% increase in genetic gain) and acted as an extra precaution against loss of the target QTL. However, for total merit index the advantage of gene-assisted genomic selection over genomic selection was lower (4–5% increase in genetic gain).Conclusion
Substantial differences between introgression programs using classical and genomic selection were observed, and the former was generally inferior with respect to both genetic gain and the ability to preserve the target QTL. Combining genomic selection with gene-assisted selection for the target QTL acted as an extra precaution against loss of the target QTL and gave additional genetic gain for disease resistance. However, the effect on total merit index was limited. 相似文献115.
Marjan Khalili Mahani Nobuyuki Inomata Alireza Saboori Baraldin Ebrahim Sayed Tabatabaei Hiroko Ishiyama Ardeshir Ariana Alfred E. Szmidt 《Experimental & applied acarology》2009,48(4):273-289
Allothrombium
pulvinum Ewing is a common natural enemy of aphids and some other arthropods. So far, there are no studies that have addressed genetic
variation of this predatory mite. We investigated genetic variation of A. pulvinum across its whole known range in Iran. A 410 bp portion of the mitochondrial cytochrome c oxidase subunit I gene (coxI) and 797–802 bp portion of the internal transcribed spacer 2 of rDNA (ITS2) were sequenced for 55 individuals from 11 populations, resulting in 12 and 26 haplotypes, respectively. In the coxI region, haplotype and nucleotide diversities varied among populations from 0.00 to 0.90 and from 0.0000 to 0.0110, respectively.
In the ITS2 region they varied from 0.20 to 0.91 and from 0.0006 to 0.0023, respectively. For both gene regions the highest haplotype
and nucleotide diversities were detected in population Mahmoud Abad from northern Iran. Statistically significant population
differentiation (F
ST) was detected in most pair-wise population comparisons. The results of population differentiation for both gene regions were
generally congruent indicating that A. pulvinum from Iran consists of genetically different populations. This suggests that A. pulvinum comprises at least two geographically distinct populations or even more than one species. This study is an initial step towards
understanding genetic variation of A. pulvinum, a taxon for which little molecular information is available. More intensive sampling and analysis of additional DNA regions
are necessary for more detailed classification of this taxon. 相似文献
116.
Binlin Dou Valerie DupontGavin Rickett Neil BlakemanPaul T. Williams Haisheng ChenYulong Ding Mojtaba Ghadiri 《Bioresource technology》2009,100(14):3540-3547
Catalytic steam reforming of glycerol for H2 production has been evaluated experimentally in a continuous flow fixed-bed reactor. The experiments were carried out under atmospheric pressure within a temperature range of 400–700 °C. A commercial Ni-based catalyst and a dolomite sorbent were used for the steam reforming reactions and in situ CO2 removal. The product gases were measured by on-line gas analysers. The results show that H2 productivity is greatly increased with increasing temperature and the formation of methane by-product becomes negligible above 500 °C. The results suggest an optimal temperature of ∼500 °C for the glycerol steam reforming with in situ CO2 removal using calcined dolomite as the sorbent, at which the CO2 breakthrough time is longest and the H2 purity is highest. The shrinking core model and the 1D-diffusion model describe well the CO2 removal under the conditions of this work. 相似文献
117.
Biodegradation of long chain n-alkanes and crude oil with fast rate and high concentration are desirable for bioremediation, especially in heavily oil-polluted areas, and enhanced oil recovery. We discovered Rhodococcus sp. Moj-3449 with such unique abilities by screening microorganisms for the growth on n-hexadecane at 30 mg/mL. The new strain grew very fast on 120 mg/mL of n-hexadecane giving a cell density of 14.7 g cdw/L after only 2 days’ incubation. During the growth with this strain, the oil–water phases were rapidly emulsified, giving rise to tolerance to high alkane concentration (250 mg/mL) and fast growth rate of 0.10–0.20 h?1 for alkane concentration of 1–180 mg/mL. The degraded concentration of n-hexadecane increased linearly with the initial alkane concentration (1–250 mg/mL). Incubation on n-hexadecane at 250 mg/mL for 7 days gave a cell density of 13.5 g cdw/L and degraded 124 mg/mL of n-hexadecane. The strain grew also fast on n-dodecane (C12), n-tetradecane (C14), and n-octadecane (C18), with degradation preference of C14 (=C16) > C12 > C18. Different from many alkane-degrading strains, Rhodococcus sp. Moj-3449 was found to have subterminal oxidation pathway. Rhodococcus sp. Moj-3449 degraded also crude oil fast at 60–250 mg/mL, with a wide range of n-alkanes (C10–C35) as substrates in which C14–C19 are preferred. The degradation ability increased with initial oil concentration from 60 to 150 mg/mL and slightly decreased afterwards. Incubation on 150 mg/mL of crude oil for 7 days degraded 37% of n-alkanes. The outstanding ability of rapidly degrading long chain n-alkanes and crude oil at high concentration makes Rhodococcus sp. Moj-3449 potentially useful for bioremediation and microbial enhanced oil recovery. 相似文献
118.
Sepideh Torabi Matthias Wissuwa Manzar Heidari Mohammad‐Reza Naghavi Kambiz Gilany Mohammad‐Reza Hajirezaei Mansoor Omidi Bahman Yazdi‐Samadi Abdelbagi M. Ismail Ghasem Hosseini Salekdeh Dr. 《Proteomics》2009,9(1):159-170
Mineral deficiency limits crop production in most soils and in Asia alone, about 50% of rice lands are phosphorous deficient. In an attempt to determine the mechanism of rice adaptation to phosphorous deficiency, changes in proteome patterns associated with phosphorous deficiency have been investigated. We analyzed the parental line Nipponbare in comparison to its near isogenic line (NIL6‐4) carrying a major phosphorous uptake QTL (Pup1) on chromosome 12. Using 2‐DE, the proteome pattern of roots grown under 1 and 100 μM phosphorous were compared. Out of 669 proteins reproducibly detected on root 2‐DE gels, 32 proteins showed significant changes in the two genotypes. Of them, 17 proteins showed different responses in two genotypes under stress condition. MS resulted in identification of 26 proteins involved in major phosphorous deficiency adaptation pathways including reactive oxygen scavenging, citric acid cycle, signal transduction, and plant defense responses as well as proteins with unknown function. Our results highlighted a coordinated response in NIL in response to phosphorous deficiency which may confer higher adaptation to nutrient deficiency. 相似文献
119.
Mosa Tavassoli Amir Ahmadi Abbas Imani Emad Ahmadiara Shahram Javadi Mojtaba Hadian 《The Korean journal of parasitology》2010,48(2):145-149
Medically important arthropods, including fleas, play an important role in causing clinical disorders and disease in man and domestic animals. This study was conducted to determine the seasonal flea infestations for domestic dogs from different geographic regions of Iran. A total of 407 fleas, belonging to 5 different species, were recovered from 83 domestic dogs from 3 regions. There was a distinctive pattern of species distribution and infestations with the highest infestation rates observed in a temperate climate and higher rainfall. Additionally, fleas were observed over all seasons, except February and March, with the highest infestation rate observed in August (24.7%) and the lowest rate in January (1.7%). They also parasitize dogs with a different spectrum of species. The cat flea, Ctenocephalides felis (67.5%), exhibited the highest prevalence among all flea species found on dogs. Thus, climatic conditions and seasonal patterns impact on flea infestation and must be considered in developing control programs. 相似文献
120.
New ammonoid species of the genus Araxoceras (A. abarquense sp. nov. and A. iranense sp. nov.) are described from the Early Dzhulfian (Early Wuchiapingian) beds of the Hambast Formation of Central Iran (Abade).
The data on the distribution of Paraceltites (Paraceltites sp.) and Vedioceras (V. umbonovarum Ruzhencev), for the first time discovered in the Dzhulfian beds of Abade, and of Eoaraxoceras are provided. The correlation of the Late Permian assemblages of ammonoids of Iran and Transcaucasia is amended. 相似文献