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991.
992.
Stano Pekár Radek Michalko Stanislav Korenko Ondřej Šedo Eva Líznarová Lenka Sentenská Zbyněk Zdráhal 《Zoology (Jena, Germany)》2013,116(1):27-35
Several hypotheses have been put forward to explain the evolution of prey specificity (stenophagy). Yet little light has so far been shed on the process of evolution of stenophagy in carnivorous predators. We performed a detailed analysis of a variety of trophic adaptations in one species. Our aim was to determine whether a specific form of stenophagy, myrmecophagy, has evolved from euryphagy via parallel changes in several traits from pre-existing characters. For that purpose, we studied the trophic niche and morphological, behavioural, venomic and physiological adaptations in a euryphagous spider, Selamia reticulata. It is a species that is branching off earlier in phylogeny than stenophagous ant-eating spiders of the genus Zodarion (both Zodariidae). The natural diet was wide and included ants. Laboratory feeding trials revealed versatile prey capture strategies that are effective on ants and other prey types. The performance of spiders on two different diets – ants only and mixed insects – failed to reveal differences in most fitness components (survival and developmental rate). However, the weight increase was significantly higher in spiders on the mixed diet. As a result, females on a mixed diet had higher fecundity and oviposited earlier. No differences were found in incubation period, hatching success or spiderling size. S. reticulata possesses a more diverse venom composition than Zodarion. Its venom is more effective for the immobilisation of beetle larvae than of ants. Comparative analysis of morphological traits related to myrmecophagy in the family Zodariidae revealed that their apomorphic states appeared gradually along the phylogeny to derived prey-specialised genera. Our results suggest that myrmecophagy has evolved gradually from the ancestral euryphagous strategy by integrating a series of trophic traits. 相似文献
993.
B. Stibůrková E. Pospíšilová S. Kmoch I. Šebesta 《Nucleosides, nucleotides & nucleic acids》2013,32(9-11):1301-1304
Excretion fraction of uric acid (EFUA), is one of the most important hallmarks for diagnosis of familial juvenile hyperuricemic nephropathy (FJHN) and hereditary renal hypouricemia. EFUA was measured in 20 patients with FJHN. However, low excretion fraction (<6%) was found also in healthy FJHN family members and healthy controls (ref. ranges EFUA: men 6–12%, women 6–20%). Similar finding of low EFUA was reported recently. Distribution of EFUA was further studied in 2,416 healthy controls, which were selected from 6,000 samples and divided according to age. In conclusion, finding of low EFUA in family members is a risk factor for renal damage and indication for purine metabolic investigations with subsequent molecular biology analysis. As EFUA could be found also in healthy controls—it should be interpreted with care and other features of FJHN (such as hyperuricemia, progressive renal disease in family) should be taken to account. 相似文献
994.
We present an improved method for microphotometric measurement of enzyme activity in muscle fibres by determining maximum
reaction rates using computer-assisted image analysis. The method was used to determine absolute and relative activities of
succinate dehydrogenase (SDH) in 4801 whole-fibre cross-sections of rabbit tibialis anterior muscles stimulated at low frequency
(10 Hz) for different time periods of up to 50 days. Measurements were performed on cross-sections of composite blocks from
stimulated and contralateral control muscles. The validity of the method was checked by determining SDH activity in homogenates
of the same muscles using a standard photometric assay. Both methods yielded similar results for the time-dependent increases
of SDH activity in response to chronic low-frequency stimulation. Significant increases in catalytic activity were detected
by the two methods only in muscles stimulated for longer than 8 days. According to homogenate measurements, overall SDH activity
was 7.4-fold elevated in 50-day-stimulated total muscles. Depending on whether or not measurements were corrected for the
so-called nothing-dehydrogenase activity, the average increase in microphotometrically determined SDH activity amounted to
approximately 8-fold or 10-fold, respectively. Microphotometry revealed pronounced scattering of SDH activities within the
fibre populations of both normal and stimulated muscles. The heterogeneity of the fibre population with regard to SDH activity
increased in long-term stimulated muscles ranging between 5-fold and 15-fold elevations.
Accepted: 2 September 1996 相似文献
995.
Brain Cell Biology - This paper describes the early stages of impregnation by the Golgi method. Sections of aldehyde-fixed and potassium dichromate-treated cerebral cortex were mounted on glass... 相似文献
996.
Kim Vriens Tanne L. Cools Peta J. Harvey David J. Craik Pieter Spincemaille David Cassiman Annabel Braem Jozef Vleugels Peter H. Nibbering Jan Wouter Drijfhout Barbara De Coninck Bruno P. A. Cammue Karin Thevissen 《PloS one》2015,10(8)
Plant defensins are small, cysteine-rich peptides with antifungal activity against a broad range of yeast and fungi. In this study we investigated the antibiofilm activity of a plant defensin from coral bells (Heuchera sanguinea), i.e. HsAFP1. To this end, HsAFP1 was heterologously produced using Pichia pastoris as a host. The recombinant peptide rHsAFP1 showed a similar antifungal activity against the plant pathogen Fusarium culmorum as native HsAFP1 purified from seeds. NMR analysis revealed that rHsAFP1 consists of an α-helix and a triple-stranded antiparallel β-sheet stabilised by four intramolecular disulfide bonds. We found that rHsAFP1 can inhibit growth of the human pathogen Candida albicans as well as prevent C. albicans biofilm formation with a BIC50 (i.e. the minimum rHsAFP1 concentration required to inhibit biofilm formation by 50% as compared to control treatment) of 11.00 ± 1.70 μM. As such, this is the first report of a plant defensin exhibiting inhibitory activity against fungal biofilms. We further analysed the potential of rHsAFP1 to increase the activity of the conventional antimycotics caspofungin and amphotericin B towards C. albicans. Synergistic effects were observed between rHsAFP1 and these compounds against both planktonic C. albicans cells and biofilms. Most notably, concentrations of rHsAFP1 as low as 0.53 μM resulted in a synergistic activity with caspofungin against pre-grown C. albicans biofilms. rHsAFP1 was found non-toxic towards human HepG2 cells up to 40 μM, thereby supporting the lack of a general cytotoxic activity as previously reported for HsAFP1. A structure-function study with 24-mer synthetic peptides spanning the entire HsAFP1 sequence revealed the importance of the γ-core and its adjacent regions for HsAFP1 antibiofilm activity. These findings point towards broad applications of rHsAFP1 and its derivatives in the field of antifungal and antibiofilm drug development. 相似文献
997.
Anne Wibaux Priyaleela Thota Jozef Mastej Daniel L. Prince Neal Carty Peter Johnson 《PloS one》2015,10(11)
Background
Covering insertion sites with chlorhexidine impregnated dressings has been proven to be clinically effective in reducing catheter related blood stream infections (CR-BSI). Two chlorhexidine gluconate (CHG)-impregnated dressings are commercially available, a polyurethane foam disk and a film dressing containing a chlorhexidine gluconate-impregnated gel pad. While both have demonstrated efficacy in clinical settings, the major drawback of high cost and impaired IV insertion site visibility limits their usage. A new, simple film dressing containing CHG within its adhesive layer is now available. The objective of this study was to test the in vitro antimicrobial efficacy of the new dressing in comparison to the CHG-impregnated gel dressing.Methods
Quantitative aliquots of suspensions (concentration of 1.0x106 to 5.0x106 cfu/sample) of clinically relevant challenge organisms (Staphylococcus species, gram-negative bacilli, Candida albicans) were incubated in contact with the new CHG-containing film dressing, a placebo version of the same (negative control) and the commercially available CHG-impregnated gel dressing (positive control). Serial dilutions of the surviving organisms were quantified using the pour plate after 1, 3, 5, and 7 days of incubation in order to calculate an antimicrobial log10 reduction for each organism/dressing combination at each point in time.Results
The new CHG-containing film dressing delivered greater than 5.0 log10 reduction throughout the 7 days on all aerobic gram-negative bacilli and Staphylococcus species tested. As of day 1 the CHG-containing film dressing provided greater than 5.0 log10 reduction on Candida albicans. There were no statistically significant differences in the log10 reduction between the two dressings tested.Conclusion
The new CHG-containing film dressing was found to be as effective as the chlorhexidine gluconate-impregnated gel dressing on clinically relevant microbes. 相似文献998.
Antonio Montresor David Addiss Marco Albonico Said Mohammed Ali Steven K. Ault Albis-Francesco Gabrielli Amadou Garba Elkhan Gasimov Theresa Gyorkos Mohamed Ahmed Jamsheed Bruno Levecke Pamela Mbabazi Denise Mupfasoni Lorenzo Savioli Jozef Vercruysse Aya Yajima 《PLoS neglected tropical diseases》2015,9(10)
999.
Adipokine zinc‐α2‐glycoprotein regulated by growth hormone and linked to insulin sensitivity 下载免费PDF全文
1000.
Klaus Stark Rainer H Straub Jozef Rovensky Stanislava Bla?i?ková Gabriele Eiselt Martin Schmidt 《Arthritis research & therapy》2015,17(1)
IntroductionRheumatoid arthritis (RA) is characterized by decreased androgen levels, which was the first hormonal abnormality described. Several studies indicated that steroidogenesis is directed towards endogenous glucocorticoids at the expense of androgens. The decisive step governing androgen synthesis is the 17,20-lyase activity of the CYP17A1 gene-encoded enzyme cytochrome P450 17A1. Here, we focused on the role in RA of the critical cofactor for 17,20-lyase activity, cytochrome b5, encoded by the CYB5A gene.MethodsData sets of two genome wide RA association studies (GWAS) were screened for single nucleotide polymorphisms (SNP) in the CYB5A gene. Candidate SNPs in CYB5A were studied in a case–control study population of Slovakia. Expression analyses were done in synovial fibroblasts from RA patients by quantitative real-time polymerase chain reaction, and cytochrome b5–expression was detected by immunohistochemistry. Real-life androgen production after steroid conversion was measured using radiolabeled substrates.ResultsThe study identified the RA-associated intronic SNP rs1790834 in the CYB5A gene in one GWAS and confirmed the same SNP in our study. The minor allele reduced RA risk selectively in women (P = 4.1*10−3; OR = 0.63, 95% CI [0.46-0.86]). The protective effect was confined to rheumatoid factor-positive (OR = 0.53, [0.37-0.75]) and anti-cyclic citrullinated peptide-positive (OR = 0.58, [0.41-0.83]) cases, respectively. The protective allele doubles CYB5A mRNA-expression resulting in 2-3fold activation of steroid 17,20-lyase activity, and protective allele was accompanied by a higher density of cytochrome b5-positive cells in synovial tissue.ConclusionsCYB5A is the first RA susceptibility gene involved in androgen synthesis. Our functional analysis of SNP rs1790834 indicates that it contributes to the sex bias observed in RA. 相似文献