排序方式: 共有57条查询结果,搜索用时 15 毫秒
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Roman Pantůček Pavel Švec Joseph J. Dajcs Ivana Machová Jitka Černohlávková Ondrej Šedo Tereza Gelbíčová Ivana Mašlaňová Jiří Doškař Zbyněk Zdráhal Vladislava Růžičková Ivo Sedláček 《Systematic and applied microbiology》2013
Thirteen coagulase-negative, oxidase-negative, and novobiocin-susceptible staphylococci were isolated from human clinical specimens. The isolates were differentiated from known staphylococcal species on the basis of 16S rRNA, hsp60, rpoB, dnaJ, tuf, and gap gene sequencing, automated ribotyping, (GTG)5-PCR fingerprinting, and MALDI-TOF MS analysis. Phylogenetic analysis based on the 16S rRNA gene sequence indicated phylogenetic relatedness of the analyzed strains to Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus devriesei, and Staphylococcus lugdunensis. DNA–DNA hybridization experiments between representative strains CCM 8418T, CCM 8421T, and the closest phylogenetic neighbors confirmed that the isolates represent novel Staphylococcus species, for which the name Staphylococcus petrasii sp. nov. is proposed. Genotypic and phenotypic analyses unambiguously split the strains into two closely related subclusters. Based on the results, two novel subspecies S. petrasii subsp. petrasii subsp. nov. and S. petrasii subsp. croceilyticus subsp. nov. are proposed, with type strains CCM 8418T (=CCUG 62727T) and CCM 8421T (=CCUG 62728T), respectively. 相似文献
33.
Vlasta Korunová Zdenka Škodová Jiří Dědina Zdeněk Valenta Jiří Pařizek Zbyněk Píša Miroslav Stýblo 《Biological trace element research》1993,37(2-3):91-99
The serum selenium levels in 367 healthy adult (25–64 yr) Central Bohemia residents, 176 men and 191 women, were determined
using atomic absorption spectrometry. An extremely wide range of values was found in the whole population sample (<20–296
μg/L) as well as in each sex or age category studied. The mean selenium concentration and 95% confidence interval calculated
after logarithmic transformation of the data were 74 μg/L (71–77) for the whole population sample, 72 μg/L (67–76) for men,
and 76 μg/L (72–81) for women. About 10% of the residents exhibited serum selenium level below 45 μg/L. There was no significant
correlation between serum selenium and sex, age, or smoking status of participants. However, the lowest average level was
found in the group of heavy smoking women: 66 μg/L. The selenium status of the Central Bohemia population seems to be below
European average. Groups of residents having a very low nutritional selenium intake may be expected to occur in this population.
Dedicated to the memory of Jiří Pařízek, former head of environmental physiology research group of the Institute of Nuclear
Biology and Radiochemistry. 相似文献
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Background
To date, the Lower Cretaceous Jehol Group of western Liaoning, China has yielded five monotypic genera of anurans, including Liaobatrachus grabaui, Callobatrachus sanyanensis, Mesophryne beipiaoensis, Dalianbatrachus mengi, and Yizhoubatrachus macilentus. However, the validity and distinctness of these taxa have been questioned.Methodology/Principal Finding
We provide a comprehensive analysis of the Jehol frogs that includes a re-examination of the published taxa as well as an examination of a number of new specimens that have been collected over the past 10 years. The results show that the five previously named taxa can be referred to three species of one genus–Liaobatrachus grabaui, L. beipiaoensis comb. nov. and L. macilentus comb. nov.. The diagnosis of Liaobatrachus is revised, and a new diagnosis is provided for each species of this genus. We also establish Liaobatrachus zhaoi sp. nov., on the basis of a dozen well-preserved specimens from a new locality. This taxon is distinguished by a unique combination of characteristics, including relatively long hind limbs, a rounded rather than triangular acetabulum, and a gradually-tapering cultriform process of the parasphenoid. In addition, an unnamed frog from a higher horizon, which has narrow sacral diapophyses and particularly long legs, is different from Liaobatrachus and represents another form of anuran in the Jehol Biota.Conclusion/Significance
Comparisons with other Mesozoic and extant anurans and the primary phylogenetic analysis both suggest that Liaobatrachus is a member of the anuran crown-group and forms a polytomy with leiopelmatids (Ascaphus and Leiopelma) and the remaining crown-group anurans (Lalagobatrachia). 相似文献36.
The transition from the vegetative to reproductive stage followed by inflorescence is a critical step in plant life; therefore, studies of the genes that influence flowering time have always been of great interest to scientists. Flowering is a process controlled by many genes interacting mutually in a genetic network, and several hypothesis and models of flowering have been suggested so far. Plants in temperate climatic conditions must respond mainly to changes in the day length (photoperiod) and unfavourable winter temperatures. To avoid flowering before winter, some plants exploit a specific mechanism called vernalization. This review summarises current achievements in the study of genes controlling flowering in the dicot model species thale cress (Arabidopsis thaliana), as well as in monocot model species rice (Oryza sativa) and temperate cereals such as barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.). The control of flowering in crops is an attractive target for modern plant breeding efforts aiming to prepare locally well-adapted cultivars. The recent progress in genomics revealed the importance of minor-effect genes (QTLs) and natural allelic variation of genes for fine-tuning flowering and better cultivar adaptation. We briefly describe the up-to-date technologies and approaches that scientists may employ and we also indicate how these modern biotechnological tools and “-omics” can expand our knowledge of flowering in agronomically important crops. 相似文献
37.
Julien Pottier Zbyněk Malenovsky Achilleas Psomas Lucie Homolová Michael E. Schaepman Philippe Choler Wilfried Thuiller Antoine Guisan Niklaus E. Zimmermann 《Biology letters》2014,10(7)
Remote sensing using airborne imaging spectroscopy (AIS) is known to retrieve fundamental optical properties of ecosystems. However, the value of these properties for predicting plant species distribution remains unclear. Here, we assess whether such data can add value to topographic variables for predicting plant distributions in French and Swiss alpine grasslands. We fitted statistical models with high spectral and spatial resolution reflectance data and tested four optical indices sensitive to leaf chlorophyll content, leaf water content and leaf area index. We found moderate added-value of AIS data for predicting alpine plant species distribution. Contrary to expectations, differences between species distribution models (SDMs) were not linked to their local abundance or phylogenetic/functional similarity. Moreover, spectral signatures of species were found to be partly site-specific. We discuss current limits of AIS-based SDMs, highlighting issues of scale and informational content of AIS data. 相似文献
38.
To the intranucleolar translocation of AgNORs in leukemic early granulocytic and plasmacytic precursors 总被引:2,自引:2,他引:0
Smetana K Klamová H Pluskalová M Stöckbauer P Hrkal Z 《Histochemistry and cell biology》2006,125(1-2):165-170
Early leukemic granulocytic and plasmacytic precursors were studied in vitro and in vivo to provide an information on the
intranucleolar distribution of AgNORs (silver stained nucleolus organizer regions). In most of these cells AgNORs appeared
as clusters of silver stained particles distributed in the whole nucleolar body. On the other hand, in some leukemic early
granulocytic precursors, i.e., in myeloblasts and promyelocytes enlarged AgNORs were translocated in the nucleolar peripheral
part. In addition, the number of translocated AgNORs at the nucleolar periphery was significantly smaller. Such translocation
of a reduced number of AgNORs was easily produced by experimental aging, i.e., starving of cultured leukemic early granulocytic precursors (HL-60 and K562 cells) in vitro and seems to be reversible. Similar translocation of a reduced number of AgNORs was also produced by aging of leukemic plasmacytic precursors. Thus,
the translocation of the reduced number of AgNORs to the nucleolar periphery in some blastic leukemic hematopoietic cells
might be an useful marker of their aging at the single cell level. However, more studies in this direction are required in
the future. 相似文献
39.
High level expression and purification of antimicrobial human cathelicidin LL-37 in Escherichia coli
Ján Krahulec Marcela Hyršová Stanislav Pepeliaev Jana Jílková Zbyněk Černý Jana Machálková 《Applied microbiology and biotechnology》2010,88(1):167-175
The human antimicrobial peptide LL-37 is a cationic peptide with antimicrobial activity against both Gram-positive and Gram-negative
microorganisms. This work describes the development of an expression system based on Escherichia coli capable of high production of the recombinant LL-37. The fusion protein Trx-LL-37 was expressed under control of T7 promoter.
The expression of T7 polymerase in the E. coli strain constructed in this work was controlled by regulation mechanisms of the arabinose promoter. The expression plasmid
was stabilized by the presence of parB locus which ensured higher homology of the culture during cultivation without antibiotic selection pressure. This system
was capable of producing up to 1 g of fusion protein per 1 l of culture. The subsequent semipreparative HPLC allowed us to
isolate 40 mg of pure LL-37. LL-37 showed high antimicrobial activity against both Gram-negative and Gram-positive microorganisms.
Its activity against Candida albicans was practically nonexistent. Minimal Inhibition Concentration (MIC) determined for E. coli was 1.65 μM; for Staphylococcus aureus 2.31 μM, and for Enterococcus faecalis 5.54 μM. The effects of cathelicidin on E. coli included the ability to permeabilize both cell membranes, as could be observed by the increase of β-galactosidase activity
in extracellular space in time. Physiological changes were studied by scanning electron microscopy; Gram-positive microorganisms
did not show any visible changes in cell shapes while the changes observed on E. coli cells were evident. The results of this work show that the herein designed expression system is capable of producing adequate
quantities of active human antimicrobial peptide LL-37. 相似文献
40.
Kunes M Svoboda Z Kvĕtina J Herout V Herink J Bajgar J 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2005,149(2):433-435
7-Methoxytacrine (7-MEOTA) is an acetylcholine-esterase inhibitor that is potentially useful in the therapy of some neurodegenerative disorders. L-carnitine (CRT) is a naturally occuring compound that is known to increase penetration of some compounds through biological barriers. Aim of this study was how CRT influenced transintestinal absorption transport 7-MEOTA in rat using single-pass intestinal in situ perfusion method. The rate of absorption of 7-MEOTA during luminal perfusion with single 7-MEOTA was compared with rate of absorption during simultaneous perfusion with 7-MEOTA and CRT and with absorption rate after the premedication with CRT for period of three days before beginning of perfusion. The methodical system was the perfusion of mesenterial bed (from arteria mesenterica superior to vena portae) and intestinal luminal perfusion (from duodenum to ileum). The lower transintestinal absorption in the course of simultaneously administration of CRT than just in case of perfusion with single 7-MEOTA has been found. On the contrary a significantly higher absorption of 7-MEOTA has been noted in group of rats premedicated with CRT for three consecutive days. The interpretation suggested that molecules of CRT incorporated into the metabolism of intestinal cells facilitated transport of 7-MEOTA (as a representative substance which is at least partly transferred by carrier mechanism). In case of simultaneous luminal perfusion with CRT and 7-MEOTA competitive over-saturation of carrier systems is probably. 相似文献