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31.
HANDE GURER-ORHAN HILMI ORHAN SIBEL SUZEN M. ORHAN PÜSKÜLLÜ ERDEM BUYUKBINGOL 《Journal of enzyme inhibition and medicinal chemistry》2013,28(2):241-247
New, except 1d, melatonin analogue benzimidazole derivatives were synthesized and characterized in the present study. The potential role of melatonin as an antioxidant by scavenging and detoxifying ROS raised the possibility that compounds that are analogous to melatonin can also be used for their antioxidant properties. Therefore the antioxidant effects of the newly synthesized compounds were investigated in vitro by means of their inhibitory effect on hydrogen peroxide-induced erythrocyte membrane lipid peroxidation (EMLP) and on various erythrocyte antioxidant enzymes viz. superoxide dismutase (SOD), catalase (CAT) and glucose-6-phosphate dehydrogenase (G6PD). The synthesized benzimidazole derivatives showed remarkable antioxidant activity in vitro in the H2O2-induced EMLP system. Furthermore their effects on various antioxidant enzymes are discussed and evaluated from the perspective of structure- activity relationships. 相似文献
32.
MAGDALENA WITEK PIOTR NOWICKI EWA B. ŚLIWIŃSKA PIOTR SKÓRKA JOSEF SETTELE KARSTEN SCHÖNROGGE MICHAL WOYCIECHOWSKI 《Ecological Entomology》2010,35(5):557-564
1. Phengaris butterflies are obligatory social parasites of Myrmica ants. Early research suggested that there is a different Myrmica host species for each of the five European Phengaris social parasites, but more recent studies have shown that this was an oversimplification. 2. The pattern of host ant specificity within a Phengaris teleius metapopulation from southern Poland is reported. A combination of studying the frequency distribution of Phengaris occurrence and morphometrics on adult butterflies were used to test whether use of different host species is reflected in larval development. 3. Phengaris teleius larvae were found to survive in colonies of four Myrmica species: M. scabrinodis, M. rubra, M. ruginodis, and M. rugulosa. Myrmica scabrinodis was the most abundant species under the host plant but the percentage of infested nests was similar to other host ant species at two sites and lower in comparison to nests of M. rubra and M. ruginodis at the other two sites. Morphometric measurements of adult butterflies reared by wild colonies of M. scabrinodis and M. ruginodis showed that wing size and number of wing spots were slightly greater for adults eclosing from nests of M. ruginodis. 4. Our results suggest that P. teleius in the populations studied is less specialised than previously suggested. The results are consistent with the hypothesis that P. teleius is expected to be the least specific of the European Phengaris species, as it has the largest and best defended fourth‐instar caterpillars and, as a predatory species, it spends less time in the central larval chambers of the host colonies. The fact that individuals reared by M. ruginodis had wider hind wings may suggest that P. teleius had better access to resources in M. ruginodis than in M. scabrinodis colonies. 相似文献
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Waliza Ansar Sumi Mukhopadhyay SK. Hasan Habib Shyamasree Basu Bibhuti Saha Asish Kumar Sen CN. Mandal Chitra Mandal 《Glycoconjugate journal》2009,26(9):1151-1169
Human C-reactive protein (CRP), as a mediator of innate immunity, removed damaged cells by activating the classical complement
pathway. Previous studies have successfully demonstrated that CRPs are differentially induced as glycosylated molecular variants
in certain pathological conditions. Affinity-purified CRPs from two most prevalent diseases in India viz. tuberculosis (TB) and visceral leishmaniasis (VL) have differential glycosylation in their sugar composition and linkages. As anemia is a common manifestation in TB and
VL, we assessed the contributory role of glycosylated CRPs to influence hemolysis via CRP-complement-pathway as compared to
healthy control subjects. Accordingly, the specific binding of glycosylated CRPs with erythrocytes was established by flow-cytometry
and ELISA. Significantly, deglycosylated CRPs showed a 7–8-fold reduced binding with erythrocytes confirming the role of glycosylated
moieties. Scatchard analysis revealed striking differences in the apparent binding constants (104–105 M−1) and number of binding sites (106–107sites/erythrocyte) for CRP on patients’ erythrocytes as compared to normal. Western blotting along with immunoprecipitation
analysis revealed the presence of distinct molecular determinants on TB and VL erythrocytes specific to disease-associated
CRP. Increased fragility, hydrophobicity and decreased rigidity of diseased-erythrocytes upon binding with glycosylated CRP
suggested membrane damage. Finally, the erythrocyte-CRP binding was shown to activate the CRP-complement-cascade causing hemolysis,
even at physiological concentration of CRP (10 μg/ml). Thus, it may be postulated that CRP have a protective role towards
the clearance of damaged-erythrocytes in these two diseases. 相似文献
35.
Human red and green visual pigment genes are X-linked duplicate genes. To
study their evolutionary history, introns 2 and 4 (1,987 and 1,552 bp,
respectively) of human red and green pigment genes were sequenced.
Surprisingly, we found that intron 4 sequences of these two genes are
identical and that the intron 2 sequences differ by only 0.3%. The low
divergences are unexpected because the duplication event producing the two
genes is believed to have occurred before the separation of the human and
Old World monkey (OWM) lineages. Indeed, the divergences in the two introns
are significantly lower than both the synonymous divergence (3.2% +/- 1.1%)
and the nonsynonymous divergence (2.0% +/- 0.5%) in the coding sequences
(exons 1-6). A comparison of partial sequences of exons 4 and 5 of human
and OWM red and green pigment genes supports the hypothesis that the gene
duplication occurred before the human-OWM split. In conclusion, the high
similarities in the two intron sequences might be due to very recent gene
conversion, probably during evolution of the human lineage.
相似文献
36.
Yvonne A Kwaffo Mabel Sarpong-Duah Kwabena Owusu-Boateng Winfred SK Gbewonyo Jonathan P Adjimani Lydia Mosi 《Experimental biology and medicine (Maywood, N.J.)》2021,246(17):1884
Mycobacterium ulcerans produces a macrolide exotoxin, mycolactone which suppresses immune cells activity, is toxic to most cells and the key virulence factor in the pathogenesis of Buruli ulcer disease. Mycolactone is reported to mediate the production of reactive oxygen species in keratinocytes; cells that play critical role in wound healing. Increased levels of reactive oxygen species have been shown to disrupt the well-ordered process of wound repair; hence, the function of wound-healing cells such as macrophages, keratinocytes, and fibroblast could be impaired in the presence of the reactive oxygen species mediator, mycolactone. To ensure regeneration of tissues in chronic ulcers, with proper and timely healing of the wounds, natural antioxidants that can combat the effects of induced reactive oxygen species in wound-healing cells ought to be investigated. Reactive oxygen species activity was determined in mycolactone-treated RAW 264.7 macrophages and the scavenging ability of the antioxidants (ascorbic acid, gallic acid, and green tea kombucha) against mycolactone-induced reactive oxygen species (superoxide anions) was assessed using fluorescein probe (DCF-DA) and nitroblue tetrazolium dye. Cytotoxicity of the antioxidants, mycolactone, and the protective effect of the antioxidants on the cells upon treatment with mycolactone were determined using the Alamar blue assay. The expression levels of endogenous antioxidant enzyme genes (superoxide dismutase, catalase, and glutathione peroxidase) in response to mycolactone-mediated reactive oxygen species were determined using RT-qPCR. Mycolactone induced the production of reactive oxygen species in RAW 264.7 macrophages, and the resulting superoxide anions were scavenged by some of the antioxidants. The selected endogenous antioxidant enzyme genes in the macrophages were upregulated in the presence of the antioxidants and mycolactone. The exogenously supplied ascorbic acid and green tea kombucha offered moderate protection to the macrophages against the toxicity of mycolactone. We conclude that the results provide insights into alternate and adjunct therapeutic approaches in Buruli ulcer treatment, which could significantly attenuate the toxicity of the pathogenic factor; mycolactone. 相似文献
37.
A.?GraffEmail author D.?Tropel SK.?Raman G.?Machaidze U.?Aebi P.?BurkhardEmail author 《NanoBioTechnology》2005,1(3):293-294
A challenging topic in cancer research is to create drug delivery system that can bring in a specific and noncytotoxic manner
a therapeutic compound. Usually, tumor targeting requires very specific compounds. Currently, peptide analogues like somatostatin,
neurotensin, or bombesin are used to target G-coupled receptors, which are overexpressed on tumor cells. However, many of
those analogues are rapidly degraded in the plasma and are cytotoxic [1–2]. Due to the limited efficiency and high toxicity
of conventional chemotherapy different strategies have been developed for non-cytotoxic cancer treatment and cancer localization
[3–5].
The recent development in bio-nanotechnology offers new avenues for cancer therapy. A lot of studies have been devoted to
nanoparticulate delivery systems (10–100nm) like lipid or polymer particles [6–8]. Due to the nanometer sized of such cargos,
the transportation of therapeutic compounds in the blood stream is increased in terms of time circulation. But their surface
functionalization to improve drug-targeting properties is usually complicated and rather uneffective.
We have recently designed a novel type of functional nanoparticles with regular icosahedral symmetry, mimicking small, rigid
viral capsids (Fig. 1 (A)) and a diameter of about 17 nm (Fig. 1 (C)) which self-assemble from single polypeptide chains (Fig.
1 (B)). 相似文献
38.
Human C-reactive protein (CRP) is a clinically important classical acute phase protein. Although CRP has been reported to
bind with many nucleated cells, the direct binding of CRP to erythrocytes in diseases remains largely unexplored. The main
focus of the present study was to investigate the binding of disease-specific CRP to erythrocytes of same patients. Distinct
molecular variant of disease-specific CRP was affinity purified from sera of malaria patients (CRPMal). This CRP showed strong binding with malaria erythrocytes (RBCMal) as confirmed by flow cytometric analysis (FACS), enzyme-linked immunosorbent assays (ELISA), and radio binding assays. Calcium
and phosphoryl choline (PC) were found to be essential for this interaction. A 2.3-fold increased binding of induced CRP to
RBCMal as compared to normal erythrocytes (RBCN) confirmed disease-specificity. Preincubation of RBCMal with unconjugated CRP showed 3–5 fold inhibition. The association constant of CRP and RBCMal was 4.7 × 106 cpm/μg with the corresponding number of receptors/cell being 4.3 × 105. The effector function of CRPMal has been demonstrated by its potency to activate the complement pathway. An optimal dose of 10 μg/ml of CRP induced three-fold
higher hemolysis of patient erythrocytes as compared to RBCN. These studies provide direct evidence for an important phagocytic functional interaction of this acute-phase protein by
triggering the CRP-complement pathway after the binding of CRPMal with RBCMal. Hemolysis as triggered by this pathway may be one of the causative factors of anemia, a common clinical manifestation of
this disease. 相似文献
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