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31.
Cervical cancer is the major cause of cancer related deaths in women, especially in developing countries and Human Papilloma Virus infection in conjunction with multiple deregulated signaling pathways leads to cervical carcinogenesis. TGF-β signaling in later stages of cancer is known to induce epithelial to mesenchymal transition promoting tumor growth. Phytochemicals, curcumin and emodin, are effective as chemopreventive and chemotherapeutic compounds against several cancers including cervical cancer. The main objective of this work was to study the effect of curcumin and emodin on TGF-β signaling pathway and its functional relevance to growth, migration and invasion in two cervical cancer cell lines, SiHa and HeLa. Since TGF-β and Wnt/β-catenin signaling pathways are known to cross talk having common downstream targets, we analyzed the effect of TGF-β on β-catenin (an important player in Wnt/β-catenin signaling) and also studied whether curcumin and emodin modulate them. We observed that curcumin and emodin effectively down regulate TGF-β signaling pathway by decreasing the expression of TGF-β Receptor II, P-Smad3 and Smad4, and also counterbalance the tumorigenic effects of TGF-β by inhibiting the TGF-β-induced migration and invasion. Expression of downstream effectors of TGF-β signaling pathway, cyclinD1, p21 and Pin1, was inhibited along with the down regulation of key mesenchymal markers (Snail and Slug) upon curcumin and emodin treatment. Curcumin and emodin were also found to synergistically inhibit cell population and migration in SiHa and HeLa cells. Moreover, we found that TGF-β activates Wnt/β-catenin signaling pathway in HeLa cells, and curcumin and emodin down regulate the pathway by inhibiting β-catenin. Taken together our data provide a mechanistic basis for the use of curcumin and emodin in the treatment of cervical cancer. 相似文献
32.
Katja Pfafferott Pooja Deshpande Elizabeth McKinnon Shahzma Merani Andrew Lucas David Heckerman Simon Mallal Mina John Silvana Gaudieri Michaela Lucas 《PloS one》2015,10(6)
Characterisation of Hepatitis C virus (HCV)-specific CD8+ T-cell responses in the context of multiple HCV exposures is critical to identify broadly protective immune responses necessary for an effective HCV vaccine against the different HCV genotypes. However, host and viral genetic diversity complicates vaccine development. To compensate for the observed variation in circulating autologous viruses and host molecules that restrict antigen presentation (human leucocyte antigens; HLA), this study used a reverse genomics approach that identified sites of viral adaptation to HLA-restricted T-cell immune pressure to predict genotype-specific HCV CD8+ T-cell targets. Peptides representing these putative HCV CD8+ T-cell targets, and their adapted form, were used in individualised IFN-γ ELISpot assays to screen for HCV-specific T-cell responses in 133 HCV-seropositive subjects with high-risk of multiple HCV exposures. The data obtained from this study i) confirmed that genetic studies of viral evolution is an effective approach to detect novel in vivo HCV T-cell targets, ii) showed that HCV-specific T-cell epitopes can be recognised in their adapted form and would not have been detected using wild-type peptides and iii) showed that HCV-specific T-cell (but not antibody) responses against alternate genotypes in chronic HCV-infected subjects are readily found, implying clearance of previous alternate genotype infection. In summary, HCV adaptation to HLA Class I-restricted T-cell responses plays a central role in anti-HCV immunity and multiple HCV genotype exposure is highly prevalent in at-risk exposure populations, which are important considerations for future vaccine design. 相似文献
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Guava (Psidium guajava L.), an important fruit crop of several tropical and sub-tropical countries, is facing several agronomic and horticultural
problems such as susceptibility to many pathogens, particularly guava wilting caused by Fusarium oxysporium psidii, low fruit growth, short shelf life of fruits, high seed content, and stress sensitivity. Conventional breeding techniques
have limited scope in improvement of guava owing to long juvenile period, self incompatibility, and heterozygous nature. Conventional
propagation methods, i.e., cutting, grafting or stool layering, for improvement of guava already exist, but the long juvenile
period has made them time consuming and cumbersome. Several biotechnological approaches such as genetic transformation may
be effective practical solutions for such problems and improvement of guava. The improvement of fruit trees through genetic
transformation requires an efficient regeneration system. During the past 2–3 decades, different approaches have been made
for in vitro propagation of guava. An overview on the in vitro regeneration of guava via organogenesis, somatic embryogenesis,
and synthetic seeds is presented. Organogenesis in several different genotypes through various explant selection from mature
tree and seedling plants has been achieved. Factors affecting somatic embryogenesis in guava have been reviewed. Production
of synthetic seeds using embryogenic propagules, i.e., somatic embryos and non-embryogenic vegetative propagules, i.e., shoot
tips and nodal segments have also been achieved. Development of synthetic seed in guava may be applicable for propagation,
short-term storage, and germplasm exchange, and distribution. An initial attempt for genetic transformation has also been
reported. The purpose of this review is to focus upon the current information on in vitro propagation and biotechnological
advances made in guava. 相似文献
36.
Shashi Kant Singh Manoj K. Rai Pooja Asthana L. Sahoo 《Acta Physiologiae Plantarum》2010,32(3):607-610
Nodal segments obtained from in vitro proliferated shoots of Eclipta alba (L.) Hassk, were encapsulated in calcium alginate beads for large-scale clonal propagation, short-term conservation and germplasm
exchange and distribution. The best gel complexation was achieved using 3% sodium alginate and 100 mM CaCl2·2H2O. Maximum percent response (100%) for conversion of encapsulated nodal segments into plantlets was obtained on 0.7% agar-solidified
full-strength MS medium containing 0.88 μM BAP. Encapsulated nodal segments could be stored at low temperature (4°C) up to
60 days with a survival frequency of 51.2%. The well-developed plantlets regenerated from encapsulated nodal segments were
hardened-off successfully with 90% survival frequency. 相似文献
37.
Anjana Jajoo Sonal Mathur Pooja Mehta Miho Yoshoika Suleyman I. Allakhverdiev Yasusi Yamamoto 《Journal of bioenergetics and biomembranes》2010,42(1):47-53
Chloride is an indispensable factor for the functioning of oxygen evolving complex (OEC) and has protective and activating
effects on photosystem II. In this study we have investigated mainly by EPR, the properties of chloride-sufficient, chloride-deficient
and chloride-depleted thylakoid membranes and photosystem II enriched membranes from spinach. The results on the effects of
different chloride depletion methods on the structural and functional aspects of photosystem II showed that chloride-depletion
by treating PS II membranes with high pH is a relatively harsh way causing a significant and irreparable damage to the PS
II donor side. Damage to the acceptor side of PS II was recovered almost fully in chloride-deficient as well as chloride-depleted
PS II membranes. 相似文献
38.
Carlos J. Sanchez Pooja Shivshankar Kim Stol Samuel Trakhtenbroit Paul M. Sullam Karin Sauer Peter W. M. Hermans Carlos J. Orihuela 《PLoS pathogens》2010,6(8)
The Pneumococcal serine-rich repeat protein (PsrP) is a pathogenicity island encoded adhesin that has been positively correlated with the ability of Streptococcus pneumoniae to cause invasive disease. Previous studies have shown that PsrP mediates bacterial attachment to Keratin 10 (K10) on the surface of lung cells through amino acids 273–341 located in the Basic Region (BR) domain. In this study we determined that the BR domain of PsrP also mediates an intra-species interaction that promotes the formation of large bacterial aggregates in the nasopharynx and lungs of infected mice as well as in continuous flow-through models of mature biofilms. Using numerous methods, including complementation of mutants with BR domain deficient constructs, fluorescent microscopy with Cy3-labeled recombinant (r)BR, Far Western blotting of bacterial lysates, co-immunoprecipitation with rBR, and growth of biofilms in the presence of antibodies and competitive peptides, we determined that the BR domain, in particular amino acids 122–166 of PsrP, promoted bacterial aggregation and that antibodies against the BR domain were neutralizing. Using similar methodologies, we also determined that SraP and GspB, the Serine-rich repeat proteins (SRRPs) of Staphylococcus aureus and Streptococcus gordonii, respectively, also promoted bacterial aggregation and that their Non-repeat domains bound to their respective SRRPs. This is the first report to show the presence of biofilm-like structures in the lungs of animals infected with S. pneumoniae and show that SRRPs have dual roles as host and bacterial adhesins. These studies suggest that recombinant Non-repeat domains of SRRPs (i.e. BR for S. pneumoniae) may be useful as vaccine antigens to protect against Gram-positive bacteria that cause infection. 相似文献
39.
Anand C Umranikar C Shintre P Damle A Kale J Joshi J Watve M 《Journal of biosciences》2007,32(4):769-774
Many species of animal-pollinated flowers are known to vary widely in the nectar content of flowers. Some proportion of flowers
in many species is apparently nectarless, and such flowers are believed to be ‘cheaters’. Cheating may explain a part of the
variability in nectar content. If cheating exists as a qualitatively different strategy then we expect bimodality in the distribution
of nectar content of flowers. It has been shown in a multispecies study that gregarious species have a higher proportion of
cheater flowers. We studied the frequency distribution of total nectar sugar in two gregariously flowering species Lantana camara and Utricularia purpurascens, which differed in other floral and ecological characters. At the population level, both the species showed significant bimodality
in the total sugar content of flowers. The obvious sources of heterogeneity in the data did not explain bimodality. In Lantana camara, bimodality was observed within flowers of some of the individual plants sampled. In Utricularia purpurascens the proportion of nectarless flowers was more in high-density patches, suggesting that the gregariousness hypothesis may
work within a species as well. The results support the hypothesis of cheating as a distinct strategy since two distinct types
of flowers were observed in both the species. The effect of density in Utricularia purpurascens also supports the gregariousness hypothesis. 相似文献
40.
We have demonstrated that the expressions of small molecular weight G-protein, H-Ras, and its effector protein, Raf-1, are
increased in the retina in diabetes, and the specific inhibitors of Ras function inhibit glucose-induced apoptosis of retinal
capillary cells. This study is to examine the contributory roles for H-Ras in glucose-induced apoptosis of retinal endothelial
cells by genetic manipulation of functionally active H-Ras levels. Bovine retinal endothelial cells were transfected with
the plasmids of either wild type (WT), constitutively active (V12) or dominant-negative (N17) H-Ras. Glucose-induced increase
in apoptosis, nitric oxide (NO) levels and activation of NF-κB and caspase-3 were determined in these genetically manipulated
cells. Exposure of bovine retinal endothelial cells to 20 mM glucose significantly increased H-Ras activation as determined
by Raf-1 binding assay. Overexpression of V12 in the endothelial cells further increased their glucose-induced apoptosis by
40%, NO levels by about 50%, and activated NF-κB and caspase-3 by about 30–40% compared to the untransfected cells incubated
in 20 mM glucose. In contrast, overexpression of the inactive mutant, N17, inhibited glucose-mediated increases in apoptotic
cell death, NO levels and NF-κB and caspase-3 activation; the values were significantly different (p < 0.02) compared to those obtained from the untransfected cells incubated under similar conditions. Our findings demonstrate
that H-Ras activation is important in the activation of the specific signaling events leading to the accelerated retinal capillary
cell apoptosis in hyperglycemic conditions, suggesting the possible use of H-Ras inhibitors to inhibit the pathogenesis of
diabetic retinopathy. 相似文献