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81.
Tertiary and quaternary structures of extracytoplasmic proteins containing more than one cysteine residue often require introduction of disulfide bonds. This process takes place in an oxidative environment, such as the periplasm of Gram-negative bacteria, and is catalyzed by Dsb (disulfide bond formation) proteins. Mutations in dsb genes influence the conformation and stability of many extracytoplasmic proteins. Thus, many pathogens become partially or fully attenuated due to improper folding of proteins that act as virulence factors. This review summarizes the current knowledge on Dsb proteins and their effect on the pathogenicity of Gram-negative bacteria. The potential application of Dsb proteins in biotechnology is also discussed. 相似文献
82.
Effects of litter traits,soil biota,and soil chemistry on soil carbon stocks at a common garden with 14 tree species 总被引:1,自引:0,他引:1
Kevin E. Mueller Sarah E. Hobbie Jon Chorover Peter B. Reich Nico Eisenhauer Michael J. Castellano Oliver A. Chadwick Tomasz Dobies Cynthia M. Hale Andrzej M. Jagodziński Izabela Kałucka Barbara Kieliszewska-Rokicka Jerzy Modrzyński Anna Rożen Maciej Skorupski Łukasz Sobczyk Małgorzata Stasińska Lidia K. Trocha January Weiner Anna Wierzbicka Jacek Oleksyn 《Biogeochemistry》2015,123(3):313-327
83.
Influence of native and alien Prunus species and light conditions on performance of the leaf beetle Gonioctena quinquepunctata
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Ewa Mąderek Adrian Łukowski Marian J. Giertych Piotr Karolewski 《Entomologia Experimentalis et Applicata》2015,155(3):193-205
The polyphagous beetle Gonioctena quinquepunctata Fabricius (Coleoptera: Chrysomelidae) is a serious leaf pest of the native European bird cherry, Prunus padus L., and the invasive alien black cherry, Prunus serotina Ehrh. (Rosaceae). In the shade, leaf damage is extensive in both species, whereas in full light, it is extensive in P. padus, but very low in P. serotina. We determined the influence of Prunus species and light conditions on differences in performance of both sexes of this folivore. In a laboratory experiment in which larvae were fed with leaves of a single species grown under particular light conditions, we measured larval, pupal, and adult mass, efficiency of conversion of ingested food (ECI), duration of development, total food eaten, and relative growth rate. In the field, we observed differences in beetle mass on shrubs of the two species growing under various light conditions. From the field observations, we hypothesised that leaves of the invasive P. serotina are not an equally good food source as leaves of P. padus for G. quinquepunctata, and the preference of these beetles for shaded shrubs is most favourable for their growth and development. Under laboratory conditions, we found that the beetle growth rate was not affected significantly by Prunus species or light conditions, despite the significant effect of light condition on the structure and chemical composition of Prunus seedlings. The lower ECI value for larvae feeding on sunlit leaves was compensated for by their higher level of consumption. In the field, adult insect mass was higher on P. padus than on P. serotina, and higher on sunlit shrubs of both species than on shaded ones. Under natural conditions, the mass of adult insects is probably also affected by other factors, such as predators and competition among folivores. 相似文献
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Ławniczak Łukasz Kaczorek Ewa Olszanowski Andrzej 《World journal of microbiology & biotechnology》2011,27(5):1183-1188
Recent biodegradation researches are focused on improving the deterioration efficiency and maintaining the stability of microbial
activity during the process. Immobilizing bacterial cells by using the adhesive method is a simple way to achieve both objectives.
The purpose of this study was to evaluate how the immobilization of bacterial cells by the biofilm forming method influences
the biodegradation efficiency of two different bacterial consortia—low diesel oil degraders (base deterioration efficiency < 40%)
and high phenol degraders (base deterioration efficiency > 90%). The degradation tests were carried out on four different
carriers (expanded clay pellets, polypropylene, polyvinyl chloride rings and paperboard). The obtained results show that biofilms
may considerably increase the efficiency of low degraders. The best diesel oil deterioration (80%) was achieved when paperboard
was used as a carrier. However, the immobilization of high degraders did not significantly influence their base biodegradation
potential. A 6% increase was noted only for the expanded clay pellets. 相似文献
87.
Katarzyna Kapczyńska Piotr Stefanowicz Łukasz Jaremko Mariusz Jaremko Alicja Kluczyk Zbigniew Szewczuk 《Amino acids》2011,40(3):923-932
Protein glycation is often a cause of diabetes-associated complications. The isotopically labeled peptide-derived Amadori
products may serve as standards for quantitative determination of the glycated proteins. In this paper, we discussed various
approaches to the synthesis of Amadori products labeled selectively with stable isotopes 2H, 13C and 18O. 相似文献
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Amphotericin B (AmB)--a polyene macrolide antibiotic--exhibits strong antifungal activity, however, is known to be very toxic to mammalian cells. In order to decrease AmB toxicity, a number of its derivatives have been synthesized. Basing on in vitro and in vivo research, it was evidenced that one of AmB derivatives, namely N-methyl-N-D-fructopyranosylamphotericin B methyl ester (in short MF-AME) retained most of the antifungal activity of the parent antibiotic, however, exhibited dramatically lower animal toxicity. Therefore, MF-AME seems to be a very promising modification product of AmB. However, further development of this derivative as potential new antifungal drug requires the elucidation of its molecular mechanism of reduced toxicity, which was the aim of the present investigations. Our studies were based on examining the binding energies by determining the strength of interaction between MF-AME and membrane sterols (ergosterol-fungi sterol, and cholesterol-mammalian sterol) and DPPC (model membrane phospholipid) using the Langmuir monolayer technique, which serves as a model of cellular membrane. Our results revealed that at low concentration the affinity of MF-AME to ergosterol is considerably stronger as compared to cholesterol, which correlates with the improved selective toxicity of this drug. It is of importance that the presence of phospholipids is essential since--due to very strong interactions between MF-AME and DPPC--the antibiotic used in higher concentration is "immobilized" by DPPC molecules, which reduces the concentration of free antibiotic, thus enabling it to selectively interact with both sterols. 相似文献
90.