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991.
The protein moiety of the Braun's E. coli outer membrane lipoprotein (Lpp-56) is an attractive object of biophysical investigation in several aspects. It is a homotrimeric, parallel coiled coil, a class of coiled coils whose stability and folding have been studied only occasionally. Lpp-56 possesses unique structural properties and exhibits extremely low rates of folding and unfolding. It is natural to ask how the specificity of the structure determines the extraordinary physical chemical properties of this protein. Recently, a seemingly controversial data on the stability and unfolding rate of Lpp-56 have been published (Dragan et al., Biochemistry 2004;43: 14891-14900; Bjelic et al., Biochemistry 2006;45:8931-8939). The unfolding rate constant measured using GdmCl as the denaturing agent, though extremely low, was substantially higher than that obtained on the basis of thermal unfolding. If this large difference arises from the effect of screening of electrostatic interactions induced by GdmCl, electrostatic interactions would appear to be an important factor determining the unusual properties of Lpp-56. We present here a computational analysis of the electrostatic properties of Lpp-56 combining molecular dynamics simulations and continuum pK calculations. The pH-dependence of the unfolding free energy is predicted in good agreement with the experimental data: the change in DeltaG between pH 3 and pH 7 is approximately 60 kJ mol(-1). The results suggest that the difference in the stability of the protein observed using different experimental methods is mainly because of the effect of the reduction of electrostatic interactions when the salt (GdmCl) concentration increases. We also find that the occupancy of the interhelical salt bridges is unusually high. We hypothesize that electrostatic interactions, and the interhelical salt bridges in particular, are an important factor determining the low unfolding rate of Lpp-56. 相似文献
992.
Muhvić-Dimanovski V 《Collegium antropologicum》2004,28(Z1):139-146
It is a well-known fact that languages react differently when foreign words denoting new concepts have to be integrated into the native system. The procedure mostly depends on the degree of purism present in a linguistic community: some languages are rather open to foreign influences and do not demonstrate any special hostility towards new words which are easily accepted and adapted to the phonological and morphological systems of the receiving language. Languages, which have a strong puristic tradition, usually channel their borrowings into the loan translation field using internal word formation resources as a means of creating neologisms. Regardless of whether they are built of native elements or appear as loans, neologisms are necessarily the result of linguistic changes. 相似文献
993.
Sanja Mijatović Alessia Bramanti Ferdinando Nicoletti Paolo Fagone Goran N. Kaluđerović Danijela Maksimović-Ivanić 《Biotechnology advances》2018,36(6):1622-1632
Differentiation of cancer cells entails the reversion of phenotype from malignant to the original. The conversion to cell type characteristic for another tissue is named transdifferentiation. Differentiation/transdifferentiation of malignant cells in high grade tumor mass could serve as a nonaggressive approach that potentially limits tumor progression and augments chemosensitivity. While this therapeutic strategy is already being used for treatment of hematological cancers, its feasibility for solid malignancies is still debated. We will presently discuss the natural compounds that show these properties, with focus on anthraquinones from Aloe vera, Senna, Rheum sp. and hop derived prenylflavonoids. 相似文献
994.
Tuna (Thunnus spp.) has been characterized by long distance migrations, highly predatory behavior and longevity, all of which in turn, enable infections with a wide spectrum of different parasitic groups, reflecting in a remarkable diversity of tuna parasite communities. Since 2003, we have been monitoring parasite communities of Atlantic bluefin tuna (Thunnus thynnus) that are caught from the wild and transferred into cages during spring-summer months, as well as assemblages in fish that exit rearing cycle during the winter harvest period after 1.5 years. Interestingly in reared tuna, parasitic populations exhibit a significant decreasing trend at the end of the rearing cycle, rarely observed in other intensive productions that represent a suitable environment for the emergence, establishment and transmission of pathogens. In order to assess epizootiological behavior of tuna parasites assemblages at the beginning (B group) and at the end (A group) of 1.5 year rearing cycle, we examined data on parasite prevalence and abundance over 4 years. The aim was to evaluate parasite diversity indices and emerging differences between newly caught and harvested fish, as well as community compositions and their nestedness in respect to the event in the rearing cycle (capture or harvest time). In order to be able to predict classification of tuna in two categories (newly caught or heavily infected and harvested or less infected fish), based on empirical didymozoids abundances and year of sampling, we built a decision tree model. Results suggest that specificities of parasite assemblages and their dynamics in tuna before and after farming have no similar precedents in aquaculture. A trend of parasitic pauperization repeating in each rearing cycle over four-years time, in once diverse and species rich parasite communities is observed, however, structures of both B and A group rearing assemblages remain nested, with the same species being core parasites (Didymosulcus katsuwonicola and Koellikerioides intestinalis). The B group exhibited significantly higher total parasite richness and mean parasites abundance, as well as the heteroxenous species richness and abundance in comparison to A group, where monoxenous species were not recorded at all. Eleven parasite species out of 26 taxa were selected as important in discriminating between B and A groups' parasites assemblages, while significantly the most abundant in B group were D. katsuwonicola, Platocystis alalongae, K. intestinalis, Koellikerioides internogastricus, Didymocystis abdominalis and Anisakis sp. It is hard to postulate the combination of factors affecting these parasite populations, but environmental, anthropogenic or host intrinsic influence has to be taken into account for further investigation. 相似文献
995.
Determining a patient's prognosis after severe traumatic brain injury remains difficult and complex. The purpose of the present study was following up patients with severe traumatic brain injury by correlating their clinical outcome and sequential computer tomography (CT) findings. We investigated 51 patients who survived the first year following an accident. All patients underwent successive CT examinations within a maximum period of 2 years. The patients' outcomes depended on the underlying brain damage and are presented by the Glasgow Outcome Scale. Based on the investigated data we concluded that the worst outcomes were experienced by patients with initial massive cerebral edema, extensive subdural hematoma and intraventricular hemorrhage, followed by stroke as subacute CT finding and cerebral atrophy as chronic finding visible at follow-up CT scans. The majority of lesions identified by CT scan were found in the frontal lobes, basal ganglia, and temporal lobes. We suggest that CT examination still represents a simple and useful tool in attempting to predict the clinical outcome in patients with severe traumatic brain injury. 相似文献
996.
Cultivated and wild Allium species were investigated in order to compare the antioxidant capacity of their leaves and bulbs. Leaf and bulb anti-oxidative
enzymes and scavenger activities, along with quantities of non-enzymic antioxidants, malonyl-dialdehyde and OH radicals were
determined. Results obtained suggest that leaves possess higher anti-oxidant and scavenging activities than bulbs in the majority
of cultivated and wild Allium species examined. Cultivation of some wild species such as A. flavum L., A. schoenoprasum L. and A. ursinum L. could be conducted in the future in order to produce Allium species with high antioxidant capacity in leaves and bulbs. 相似文献
997.
Coruasić A Barisić D Plavec A Planinić P Skrgatić L Vujić G Herman M 《Collegium antropologicum》2007,31(Z2):147-154
With correct staging a large number of patients with cervical cancer FIGO stages IA2 and IB can be spared of unnecessary radiation therapy by laparoscopic assisted vaginal radical hysterectomy (LAVRH) as an option of radical surgical treatment in such patients. The development of laparovaginal surgery, indication and contraindication were presented. Also, the surgical technique was described in detail. Fifty-two patients were followed up in 2003 after LAVRH or open surgery, performed in our single center. Only 5 (14%) patients died from cervical cancer within 3 years following the treatment. They were all clinical stage IB treated with open surgery. There were 4 (11%) complications following treatment and they were all in patients with clinical stage IB, also treated with open surgery. There was no complication in LAVRH treated patients. The results and complications of the sole Croatian center performing LAVRH or open surgery in patients with cervical cancer FIGO stages IA and IB were similar to those in centers across the world. 相似文献
998.
999.
Seol B Gomercić MD Naglić T Gomercić T Galov A Gomercić H 《Journal of wildlife diseases》2006,42(3):709-711
Bacteriologic examination of an abscess found between blubber and musculature of a striped dolphin (Stenella coeruleoalba) found dead on 30 March 2002 in the Adriatic Sea, Croatia, was performed and an aerotolerant, nontoxogenic Clostridium tertium was isolated in pure culture. National Collections of Industrial Food and Marine Bacteria (NCIMB Ltd., Aberdeen, Scotland, UK) confirmed the results. Sequencing results showed it to be C. tertium with 100% similarity. The strain was named Clostridium tertium strain Zagreb, acceded to the culture collection and assigned the accession number NCIMB 13970. This is the first record of C. tertium in marine mammals. 相似文献
1000.
Dušan Ušjak Miroslav Dinić Katarina Novović Branka Ivković Nenad Filipović Magdalena Stevanović Marina T. Milenković 《化学与生物多样性》2021,18(1):e2000786
An increasing lack of available therapeutic options against Acinetobacter baumannii urged researchers to seek alternative ways to fight this extremely resistant nosocomial pathogen. Targeting its virulence appears to be a promising strategy, as it offers considerably reduced selection of resistant mutants. In this study, we tested antibiofilm potential of four synthetic chalcone derivatives against A. baumannii. Compound that showed the greatest activity was selected for further evaluation of its antivirulence properties. Real-time PCR was used to evaluate mRNA expression of biofilm-associated virulence factor genes (ompA, bap, abaI) in treated A. baumannii strains. Also, we examined virulence properties related to the expression of these genes, such as fibronectin- and collagen-mediated adhesion, surface motility, and quorum-sensing activity. The results revealed that the expression of all tested genes is downregulated together with the reduction of adhesion and motility. The conclusion is that 2′-hydroxy-2-methoxychalcone exhibits antivirulence activity against A. baumannii by inhibiting the expression of ompA and bap genes, which is reflected in reduced biofilm formation, adhesion, and surface motility. 相似文献