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91.
International Journal of Peptide Research and Therapeutics - The progressive damage of human articular cartilage is associated with loss of integrity of its extracellular matrix components. Their...  相似文献   
92.
Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...  相似文献   
93.

Pathogens carried by ticks pose a threat to both human and animal health across the world. Typically associated with rural landscapes, ticks appear to adapt well to life in urban recreational areas. Although Dermacentor reticulatus is commonly found across Europe, data on the prevalence of pathogens in this tick species, in an urban environment, are very limited. PCR was used to examine 368 D. reticulatus individuals collected in the Zwierzyniecki Forest Nature Reserve in Bia?ystok, Poland. In total, 10.3% of ticks were infected, with Babesia spp. (9.2%), Anaplasma phagocytophilum (0.8%) and Borrelia burgdorferi sensu lato (0.3%). Rickettsia spp., Bartonella spp., and Coxiella burnetii were not detected. Sequence analysis for Babesia-positive samples identified 79.4% of them as Babesia canis, 8.8% as Babesia microti, 5.9% as Babesia spp., 2.9% as Babesia venatorum, and 2.9% as Babesia vogeli. Results obtained in this study indicate that D. reticulatus ticks found within the urban premises of the study area are infected with at least three pathogens and therefore are an important factor in public health risk for tick-borne diseases.

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94.
The dry climate that prevailed during the Triassic period in the eastern part of the Central European Basin was interrupted by several humid episodes of varying durations. One of them was the Carnian Pluvial Episode (CPE), which took place in the late Julian (early Carnian age) and is confined to Camerosporites secatus and Aulisporites astigmosus palynological zones. CPE is marked by a significant change in the qualitative and quantitative composition of spore-pollen assemblages from mostly xerophytic species preserved in the upper part of the Grabfeld Formation (“Lower Gipskeuper”) to hygrophytic forms, which dominate in the Stuttgart Formation (“Schilfsandstein”). Changes in climate towards more humid conditions have been documented palynologically and sedimentologically, and analyzed utilizing quantitative spore-pollen analysis and Principal Component Analysis (PCA) of miospores occurring in core material from Poland. In all the studied boreholes, a shift from dry to wet climate is observed at the boundary between the Grabfeld Formation and the Stuttgart Formation, which matches the data from other European regions.  相似文献   
95.
Cultured fibroblast cells, especially dermal cells, are used for various types of scientific research, particularly within the medical field. Desirable features of the cells include their ease of isolation, rapid cellular growth, and high degree of robustness. Currently, fibroblasts are mainly used to obtain pluripotent cells via a reprogramming process. Dermal fibroblasts, are particularly useful for gene therapies used for promoting wound healing or minimizing skin aging. In recent years, fibroblast transfection efficiencies have significantly improved. In order to introduce molecules (most often DNA or RNA) into cells, viral-based systems (transduction) or non-viral methods (transfection) that include physical/mechanical processes or lipid reagents may be used. In this article, we describe critical points that should be considered when selecting a method for transfecting fibroblasts. The most effective methods used for the transfection of fibroblasts include both viral-based and non-viral nucleofection systems. These methods result in a high level of transgene expression and are superior in terms of transfection efficacy and viability.  相似文献   
96.
This study was planned to evaluate structural damages in adsorbed vaccines affected by freezing using scanning electron microscopy and X-ray analysis of the elements. Randomly selected 42 vials of eight different types of WHO pre-qualified adsorbed freeze-sensitive vaccines from 10 manufacturers were included in the study. Vaccines were kept at 5 °C. Selected numbers of vials from each type were then exposed to ?25 °C for 24 h periods. All samples were evaluated for their structure using scanning electron microscopy, X-ray analysis of the elements and precipitation time. Scanning electron microscopy of vaccines affected by freezing showed either smooth or rough surfaced conglomerates associated with phosphate content of the precipitate. These vaccines precipitated 2–15 times faster compared to non-frozen samples. Non-frozen samples showed uniform flocculent structure either dense or dispersed. X-ray analysis of precipitates in frozen samples confirmed that the precipitate is mainly aluminium clutters. Scanning electron microscopy confirmed that the lattice structure of bonds between adsorbent and the antigen is broken and aluminium forms conglomerates that grow in size and weight. The precipitation time of vaccines affected by freezing is 4.5 times faster on average compared to non-frozen samples. These facts form the basis of the "shake test".  相似文献   
97.
Tobacco smoke, recognized as a major etiological factor for cancers of the upper aerodigestive tract, represents an abundant source of reactive oxygen species (ROS), which are believed to play a significant role in mutagenesis and carcinogenesis. An additional source of ROS in tissues exposed to tobacco smoke may be metabolic oxidation of polycyclic aromatic hydrocarbons (PAH). To investigate the relationships between oxidative DNA lesions and aromatic DNA adducts, six modified DNA bases 5-hydroxyuracil, 5-hydroxycytosine, 7,8-dihydro-8-oxoguanine, 7,8-dihydro-8-oxoadenine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine and 4,6-diamino-5-formamidopyrimidine and the total level of PAH-related DNA adducts were measured in cancerous and the surrounding normal larynx tissues (68 subjects), using gas chromatography/isotope-dilution mass spectroscopy with selected ion monitoring and the 32 P-postlabeling-HPLC assay, respectively. The levels of oxidative DNA lesions in cancerous and adjacent tissue were comparable; the differences between the two types of tissue were significant only for 5-hydroxypyrimidines (slightly higher levels were observed in the adjacent tissue). Comparable levels of DNA lesions in cancerous and the surrounding normal tissues observed in the larynx tumors support a field cancerization theory. The surrounding tissues may still be recognized as normal by histological criteria. However, molecular alterations resulting from the chronic tobacco smoke exposure, which equally affects larynx epithelia, may lead to multiple premalignant lesions. Thus, a demonstration of similar levels of DNA damage in cancerous and the adjacent tissue could explain a frequent formation of secondary tumors in the larynx and the frequent recurrence in this type of cancer. A weak, but distinct effect of tumor grading and metastatic status was observed in both kinds of tissue in the case of 5-hydroxyuracil, 5-hydroxycytosine, 7,8-dihydro-8-oxoguanine, 7,8-dihydro-8-oxoadenine. This effect was displayed as a gradual shift in the data distribution toward high values from G1 through G2-G3 and from non-metastatic to metastatic tumors. Since the levels of oxidative DNA base modifications tended to increase with the tumor aggressiveness, we postulate that the oxidative DNA lesions increase genetic instability and thus contribute to tumor progression in laryngeal cancer. No associations between aromatic adduct levels and oxidative DNA lesions were present, suggesting that the metabolism of PAH does not contribute significantly to the oxidative stress in larynx tissues, remaining the tobacco smoke ROS as a major source of oxidative DNA damage in the exposed tissue.  相似文献   
98.
A proteinase produced by the human gastrointestinal isolate Lactobacillus rhamnosus strain OXY was identified and characterized. The prtR2 gene coding for proteinase activity was detected in the examined strain. The PCR primers used were constructed on the basis of the sequence of the prtR2 proteinase gene from Lactobacillus rhamnosus GG. The enzyme was purified by fast protein liquid chromatography (FPLC) using CM-Sepharose Fast Flow and Sephacryl S-300 columns. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that the enzyme had a relatively low molecular mass of 60 kD. Protease activity was observed at a pH range from 6.5 to 7.5 with optimum k cat/K m values at pH 7.0 and 40°C. Maximum proteolytic activity (59 U mL?1) was achieved after 48 hr of cultivation. The activity of the enzyme was inhibited only by irreversible inhibitors specific for serine proteinases (PMSF and 3,4-dichloro-isocumarine), suggesting that the enzyme was a serine proteinase. Proteinase activity was increased by Ca2+ and Mg2+, and inhibited by Cu2+, Zn2+, Cd2+, and Fe2+.  相似文献   
99.
Tetrachloro-o-benzoquinone (TCoBQ) and tetrachloro-p-benzoquinone (TCpBQ) were studied as inhibitors of jack bean urease in 20 mM phosphate buffer, pH 7.0, 1 mM EDTA, 25°C. The mechanisms of inhibition were evaluated by analysis of the progress curves obtained with two procedures: the reaction initiated by addition of the enzyme and the reaction initiated by addition of the substrate after preincubation of the enzyme with the inhibitor. The obtained results were characteristic of slow-binding inhibition. The effects of different inhibitor concentrations on the initial and steady-state velocities obeyed the relationships of two-step enzyme-inhibitor interaction, qualified as mechanism B. It was found that TCoBQ and TCpBQ are strong urease inhibitors. TCpBQ is more effective than TCoBQ with the overall inhibition constant of Ki* = 4.5 × 10? 7 mM. The respective inhibition constant of TCoBQ was equal to: Ki* = 2.4 × 10? 6 mM. The protective experiment proved that the urease active site is involved in the tetrachlorobenzoquinone inhibition process. High effectiveness of thiol protectors against inhibition by TCoBQ and TCpBQ indicates the strategic role of the active site sulfhydryl group in the blocking process. The stability of the complexes: urease-TCoBQ and urease-TCpBQ was tested in two ways: by dilution or addition of dithiothreitol. No recovery of urease activity bound in the urease-inhibitor complexes proves that the complexes are stable and strong.  相似文献   
100.
The objective of this study was to analyse the genetic variability and phylogenetic analysis of six strains of rabbit haemorrhagic disease virus (RHDV), including four Czech strains (CAMPV-351, CAMPV-561, CAMPV-562, CAMPV-558) and two French strains (Fr-1, Fr-2), on the basis of a fragment of the VP60 capsid structural protein-coding gene N-terminal region. The results of our own studies were compared to 26 RHDV strains obtained from GenBank. The analysis of the genetic variability of six RHDV strains indicated that the CAMPV-561 strain is the most genetically variable. Less variable were the Fr-1 and Fr-2 strains, while the least variable was CAMPV-351. In turn, the genetic distance among the six analysed strains and 26 strains obtained from GenBank was the greatest for CAMPV-351 and Whn/China [11.3 % according to the observed divergence (OD) method and 12.2 % according to the maximum likelihood (ML) method], while it was the lowest for CAMPV-351 and FRG (0.8 % in both the OD and ML methods). In turn, the scale of the genetic distances among the six analysed strains and five RHDVa strains (99-05, NY-01, Whn/China, Triptis, Iowa2000) ranged from 9.3–10.3 % in the OD method to 10.3–13.7 % in the ML method. The image of phylogenetic dependencies generated for the strains analysed and those obtained from GenBank revealed their distribution to be in five genetic groups (G1–G5), whereas the analysed strains were included in genetic groups 2 and 3.  相似文献   
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