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931.
932.
Lance B. Price Cindy M. Liu Johan H. Melendez Yelena M. Frankel David Engelthaler Maliha Aziz Jolene Bowers Rogan Rattray Jacques Ravel Chris Kingsley Paul S. Keim Gerald S. Lazarus Jonathan M. Zenilman 《PloS one》2009,4(7)
Background
Bacterial colonization is hypothesized to play a pathogenic role in the non-healing state of chronic wounds. We characterized wound bacteria from a cohort of chronic wound patients using a 16S rRNA gene-based pyrosequencing approach and assessed the impact of diabetes and antibiotics on chronic wound microbiota.Methodology/Principal Findings
We prospectively enrolled 24 patients at a referral wound center in Baltimore, MD; sampled patients'' wounds by curette; cultured samples under aerobic and anaerobic conditions; and pyrosequenced the 16S rRNA V3 hypervariable region. The 16S rRNA gene-based analyses revealed an average of 10 different bacterial families in wounds—approximately 4 times more than estimated by culture-based analyses. Fastidious anaerobic bacteria belonging to the Clostridiales family XI were among the most prevalent bacteria identified exclusively by 16S rRNA gene-based analyses. Community-scale analyses showed that wound microbiota from antibiotic treated patients were significantly different from untreated patients (p = 0.007) and were characterized by increased Pseudomonadaceae abundance. These analyses also revealed that antibiotic use was associated with decreased Streptococcaceae among diabetics and that Streptococcaceae was more abundant among diabetics as compared to non-diabetics.Conclusions/Significance
The 16S rRNA gene-based analyses revealed complex bacterial communities including anaerobic bacteria that may play causative roles in the non-healing state of some chronic wounds. Our data suggest that antimicrobial therapy alters community structure—reducing some bacteria while selecting for others. 相似文献933.
Karine H. Hellemans Jean-Claude Hannaert Bart Denys Knut R. Steffensen Cindy Raemdonck Geert A. Martens Paul P. Van Veldhoven Jan-?ke Gustafsson Daniel Pipeleers 《PloS one》2009,4(9)
Chronically elevated levels of fatty acids-FA can cause beta cell death in vitro. Beta cells vary in their individual susceptibility to FA-toxicity. Rat beta cells were previously shown to better resist FA-toxicity in conditions that increased triglyceride formation or mitochondrial and peroxisomal FA-oxidation, possibly reducing cytoplasmic levels of toxic FA-moieties. We now show that stearoyl-CoA desaturase-SCD is involved in this cytoprotective mechanism through its ability to transfer saturated FA into monounsaturated FA that are incorporated in lipids. In purified beta cells, SCD expression was induced by LXR- and PPARα-agonists, which were found to protect rat, mouse and human beta cells against palmitate toxicity. When their SCD was inhibited or silenced, the agonist-induced protection was also suppressed. A correlation between beta cell-SCD expression and susceptibility to palmitate was also found in beta cell preparations isolated from different rodent models. In mice with LXR-deletion (LXRβ-/- and LXRαβ-/-), beta cells presented a reduced SCD-expression as well as an increased susceptibility to palmitate-toxicity, which could not be counteracted by LXR or PPARα agonists. In Zucker fatty rats and in rats treated with the LXR-agonist TO1317, beta cells show an increased SCD-expression and lower palmitate-toxicity. In the normal rat beta cell population, the subpopulation with lower metabolic responsiveness to glucose exhibits a lower SCD1 expression and a higher susceptibility to palmitate toxicity. These data demonstrate that the beta cell susceptibility to saturated fatty acids can be reduced by stearoyl-coA desaturase, which upon stimulation by LXR and PPARα agonists favors their desaturation and subsequent incorporation in neutral lipids. 相似文献
934.
Jürgen Scherkenbeck Horst‐Peter Antonicek Kathrin Vogelsang Tino Zdobinsky Karin Brücher Denise Rehländer Heru Chen 《Journal of peptide science》2009,15(11):783-789
Neuropeptides control numerous physiological processes in insects. The regulation of water balance is a crucial aspect of homeostasis in terrestrial insects and has been shown to be under endocrine control, primarily by corticotrophin releasing factor (CRF)‐related peptides and kinins. For helicokinin I, a diuretic neuropeptide from the economically important insect pest Heliothis virescens, detailed structure‐activity relationships have been established based on truncated structures, diverse amino acid scans and peptidomimetic analogues. The activities of selected compounds on functional expressed helicokinin receptors are compared with the results of a Malphigian tubule assay. Implications for further peptidomimetic variations are provided. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
935.
A new benthic freshwater diatom, Geissleria gereckei sp. nov., was identified from light and scanning electron micrographs. The most characteristic morphological features are the valve outline (elliptical, but with lateral margins that can range from slightly convex to slightly concave and also straight, and protracted, almost capitate ends), the size and length/width ratio, and the pattern of the striae around the central area. The new species was found to be epilithic, and characteristic of leaf-litter covered stones of very shaded carbonate mountain springs of the Italian Alps with extremely-low discharge (likely to be affected by seasonal desiccation). Very-low-discharge springs host a highly specialized diatom microflora, and are likely to increase in number in the near future due to the reduction of water, which is predicted to be caused by climate change in many regions. 相似文献
936.
LI-Cadherin is a transmembrane glycoprotein involved in cell adhesion of epithelial cells. Its supposed recognition domain contains the peptide motif AAL and is distinctly hydrophobic. In order to obtain sufficiently soluble model compounds, glycan side chains of T-antigen, (2,6)sialyl T-antigen and sialyl TN-antigen structure were linked to the serine located in the supposed turn sequence of the LI-cadherin recognition domain. A quinic acid-glycine-7-amino-coumarine (Quiglac) chromophore was constructed in order to enhance the solubility of labelled LI-cadherin (glyco)peptides in water. 相似文献
937.
Gunda Schulte auf’m Erley Titus Fondo Ambebe Mosisa Worku Marianne Bänziger Walter J. Horst 《Plant and Soil》2010,330(1-2):313-328
The selection process of nitrogen (N)-efficient cultivars during plant breeding could be simplified by a specification of secondary plant traits that are decisive for N efficiency. It was shown that leaf senescence under N deprivation of sixteen tropical maize cultivars in a short-term nutrient solution experiment was related to leaf senescence and grain yield under N deficiency (N efficiency) in field experiments. In this study we investigated if a quantification of leaf- and plant-N flows by 15N labelling can improve the evaluation of genotypic differences in leaf senescence in short-term experiments. Cultivars differed in leaf-N content prior to senescence; however, this appeared to have no significant impact on the development of leaf senescence. N import into senescing leaves was not related to total plant N uptake, but seems to have been regulated by leaf-inherent factors. Leaf N remaining in the leaf seems to have comprised inefficiently remobilized leaf N, at least during early senescence stages. Photosynthetic rate and chlorophyll contents at early senescence stages depended on additional factors to leaf-N content. Nevertheless, all parameters used to characterize leaf senescence were related to leaf senescence at anthesis in field experiments. However, only photosynthetic rate during late leaf senescence reflected cultivar differences in leaf senescence during reproductive growth and N efficiency in field experiments. 相似文献
938.
Competition for mating opportunities may involve exclusion of intrasexual competitors (direct) or defending resources necessary
to attract mates (indirect). Male swordtails (Xiphophorus helleri) engage in direct competition. Moreover in natural populations they defend a home range. This study aimed to test whether
this home range defence is a form of food resource defence, which may therefore have a female attraction function. Male swordtails
did defend a food resource and showed increased aggression in the presence of both food and females. However, food resource
defence decreased when females were present, suggesting that both food and females are treated as defendable resources. 相似文献
939.
Claassen H Steffen R Hassenpflug J Varoga D Wruck CJ Brandenburg LO Pufe T 《Cell and tissue research》2010,342(2):283-293
Clinical observations have suggested a relationship between osteoarthritis and a changed sex-hormone metabolism, especially in menopausal women. This study analyzes the effect of 17β-estradiol on expression of matrix metalloproteinases-1, -3, -13 (MMP-1, -3, -13) and tissue inhibitors of metalloproteinases-1, -2 (TIMP-1, -2) in articular chondrocytes. An imbalance of matrix metalloproteinases (MMPs) specialized on degradation of articular cartilage matrix over the respective inhibitors of these enzymes (TIMPs) that leads to matrix destruction was postulated in the pathogenesis of osteoarthritis. Primary human articular chondrocytes from patients of both genders were cultured in alginate beads at 5% O(2) to which 10(-11)M-10(-5)M 17β-estradiol had been added and analyzed by means of immunohistochemistry, immunocytochemistry and real-time RT-PCR. Since articular chondrocytes in vivo are adapted to a low oxygen tension, culture was performed at 5% O(2). Immunohistochemical staining in articular cartilage tissue from patients and immunocytochemical staining in articular chondrocytes cultured in alginate beads was positive for type II collagen, estrogen receptor α, MMP-1, and -13. It was negative for type I collagen, MMP-3, TIMP-1 and -2. Using real-time RT-PCR, it was demonstrated that physiological and supraphysiological doses of 17β-estradiol suppress mRNA levels of MMP-3 and -13 significantly in articular chondrocytes of female patients. A significant suppressing effect was also seen in MMP-1 mRNA after a high dose of 10(-5)M 17β-estradiol. Furthermore, high doses of this hormone led to tendentially lower TIMP-1 levels whereas the TIMP-2 mRNA level was not influenced. In male patients, only incubations with high doses (10(-5)M) of 17β-estradiol were followed by a tendency to suppressed MMP-1 and TIMP-1 levels while TIMP-2 mRNA level was decreased significantly. There was no effect on MMP-13 expression of cells from male patients. Taken together, application of 17β-estradiol in physiological doses will improve the imbalance between the amounts of MMPs and TIMPs in articular chondrocytes from female patients. Downregulation of TIMP-2 by 17β-estradiol in male patients would not be articular cartilage protective. 相似文献
940.
Zaïre ebolavirus (ZEBOV) infection rapidly outruns the host's immunity and leads to death within a week. Fatal cases have been associated with an aberrant innate, proinflammatory immune response followed by a suppressed adaptive response leading to the rapid depletion of peripheral NK cells and lymphocytes. A critical role for NK cells has been suggested but not elucidated. In this genetic study, we investigated the association of KIR genotype with disease outcome by comparing genotypes of a Gabonese control population, IgG+ contacts, survivors, and fatalities of ZEBOV infection. We showed that the activating KIR2DS1 and KIR2DS3 genes associate with fatal outcome in Ebola virus infection. In addition, this study brings supplemental evidence in favor of the specificity of the IgG+ contact population. The outcome of fulminating Ebola virus infection could depend in part on the host's inherited KIR gene repertoire. This supports a key role for KIRs in disease susceptibility to infections. 相似文献