170 research outputs found
Evaluation de la fertilite femelle des arabusta par le niveau de ploidie et les generations dâhybrides
Les hybrides Arabusta sont caractĂ©risĂ©s par une faible fertilitĂ© exprimĂ©e par des taux de caracolis Ă©levĂ©s et des taux de loges vides importants induisant des productivitĂ©s faibles. Pour une stratĂ©gie plus efficiente des sĂ©lections, il est important de connaĂźtre les niveaux de fertilitĂ© femelle des diffĂ©rents types de cafĂ©iers Arabusta. Ainsi donc, les fertilitĂ©s femelles de quatre gĂ©nĂ©rations (G1, G2, G3, G4) de Coffea X arabusta et dâun rĂ©trocroisement (back-cross) sur le parent arabica (BC) ont-elles Ă©tĂ© observĂ©es ainsi que celles de quatre groupes de cafĂ©iers de niveaux de ploĂŻdie diffĂ©rents (diploĂŻdes, triploĂŻdes, tĂ©traploĂŻdes et pentaploĂŻdes). Ces fertilitĂ©s ont Ă©tĂ© dĂ©terminĂ©es par 4 paramĂštres ou estimateurs de fertilitĂ© : le taux dâĂ©cailles, le taux de caracolis, le taux de loges vides et le taux de remplissage des fruits. Les valeurs moyennes de ces estimateurs obtenues chez les gĂ©nĂ©rations et le back-cross sont respectivement de : 35,16 % ; 59,70 % ; 30,37 % ; 45,34 %. En ce qui concerne les cafĂ©iers de diffĂ©rents niveaux de ploĂŻdie, les valeurs moyennes des 4 estimateurs sont les suivants : taux dâĂ©cailles 31,66 % ; taux de caracolis 51,26 % ; taux de loges vides 20,13 % et taux de remplissage des fruits 55,33 %. Les rĂ©sultats ont montrĂ© que la fertilitĂ© dĂ©pend de deux facteurs : un facteur gĂ©nĂ©tique liĂ© Ă la fertilitĂ© gamĂ©tique (Ă©cailles et caracolis), qui peut sâamĂ©liorer au cours des gĂ©nĂ©rations et un facteur physiologique liĂ© Ă la fertilitĂ© zygotique (loges vides et fructification ou remplissage des fruits), qui est fortement influencĂ© par lâenvironnement gĂ©o-morpho-climatique. Par ailleurs, le rĂ©trocroisement des Arabusta sur le parent arabica nâest pas envisageable dans le contexte cafĂ©icole de CĂŽte dâIvoire. Enfin, cette Ă©tude a permis dâĂ©tablir les normes dâutilisation des diploĂŻdes, des triploĂŻdes et des pentaploĂŻdes. Ces derniers ont un niveau de fertilitĂ© comparable aux tĂ©traploĂŻdes et constituent une voie Ă explorer.Mots clĂ©s : Hybrides interspĂ©cifiques, fertilitĂ© femelle, gĂ©nĂ©ration
The RUNX2 transcription factor cooperates with the YES-associated protein, YAP65, to promote cell transformation
Anti-tumor therapy with macroencapsulated endostatin producer cells
<p>Abstract</p> <p>Background</p> <p>Theracyte is a polytetrafluoroethylene membrane macroencapsulation system designed to induce neovascularization at the tissue interface, protecting the cells from host's immune rejection, thereby circumventing the problem of limited half-life and variation in circulating levels. Endostatin is a potent inhibitor of angiogenesis and tumor growth. Continuous delivery of endostatin improves the efficacy and potency of the antitumoral therapy. The purpose of this study was to determine whether recombinant fibroblasts expressing endostatin encapsulated in Theracyte immunoisolation devices can be used for delivery of this therapeutic protein for treatment of mice bearing B16F10 melanoma and Ehrlich tumors.</p> <p>Results</p> <p>Mice were inoculated subcutaneously with melanoma (B16F10 cells) or Ehrlich tumor cells at the foot pads. Treatment began when tumor thickness had reached 0.5 mm, by subcutaneous implantation of 10<sup>7 </sup>recombinant encapsulated or non-encapsulated endostatin producer cells. Similar melanoma growth inhibition was obtained for mice treated with encapsulated or non-encapsulated endostatin-expressing cells. The treatment of mice bearing melanoma tumor with encapsulated endostatin-expressing cells was decreased by 50.0%, whereas a decrease of 56.7% in tumor thickness was obtained for mice treated with non-encapsulated cells. Treatment of Ehrlich tumor-bearing mice with non-encapsulated endostatin-expressing cells reduced tumor thickness by 52.4%, whereas lower tumor growth inhibition was obtained for mice treated with encapsulated endostatin-expressing cells: 24.2%. Encapsulated endostatin-secreting fibroblasts failed to survive until the end of the treatment. However, endostatin release from the devices to the surrounding tissues was confirmed by immunostaining. Decrease in vascular structures, functional vessels and extension of the vascular area were observed in melanoma microenvironments.</p> <p>Conclusions</p> <p>This study indicates that immunoisolation devices containing endostatin-expressing cells are effective for the inhibition of the growth of melanoma and Ehrlich tumors.</p> <p>Macroencapsulation of engineered cells is therefore a reliable platform for the refinement of innovative therapeutic strategies against tumors.</p
Navigating Scholarly Development Through a CoP: #generational-lenses
CoPs provide opportunity for professional identity exploration. Extant research neglects how multiple identities, including generational memberships, influence development. This study explores professional identity development of scholars within a multigenerational CoP
Unexpected Learning: Development of the CoP and Its Members #generational-shift
Our research explores how multigenerational CoPs may provide graduate students, particularly doctoral students, the space to explore and develop their professional identities and find their scholarly voices
Exploratory spatial data analysis for the identification of risk factors to birth defects
BACKGROUND: Birth defects, which are the major cause of infant mortality and a leading cause of disability, refer to "Any anomaly, functional or structural, that presents in infancy or later in life and is caused by events preceding birth, whether inherited, or acquired (ICBDMS)". However, the risk factors associated with heredity and/or environment are very difficult to filter out accurately. This study selected an area with the highest ratio of neural-tube birth defect (NTBD) occurrences worldwide to identify the scale of environmental risk factors for birth defects using exploratory spatial data analysis methods. METHODS: By birth defect registers based on hospital records and investigation in villages, the number of birth defects cases within a four-year period was acquired and classified by organ system. The neural-tube birth defect ratio was calculated according to the number of births planned for each village in the study area, as the family planning policy is strictly adhered to in China. The Bayesian modeling method was used to estimate the ratio in order to remove the dependence of variance caused by different populations in each village. A recently developed statistical spatial method for detecting hotspots, Getis's [Image: see text] [7], was used to detect the high-risk regions for neural-tube birth defects in the study area. RESULTS: After the Bayesian modeling method was used to calculate the ratio of neural-tube birth defects occurrences, Getis's [Image: see text] statistics method was used in different distance scales. Two typical clustering phenomena were present in the study area. One was related to socioeconomic activities, and the other was related to soil type distributions. CONCLUSION: The fact that there were two typical hotspot clustering phenomena provides evidence that the risk for neural-tube birth defect exists on two different scales (a socioeconomic scale at 6.84 km and a soil type scale at 22.8 km) for the area studied. Although our study has limited spatial exploratory data for the analysis of the neural-tube birth defect occurrence ratio and for finding clues to risk factors, this result provides effective clues for further physical, chemical and even more molecular laboratory testing according to these two spatial scales
Precise Measurements of Branching Fractions for Meson Decays to Two Pseudoscalar Mesons
We measure the branching fractions for seven two-body decays to
pseudo-scalar mesons, by analyzing data collected at
GeV with the BESIII detector at the BEPCII collider. The branching fractions
are determined to be ,
,
,
,
,
,
,
where the first uncertainties are statistical, the second are systematic, and
the third are from external input branching fraction of the normalization mode
. Precision of our measurements is significantly improved
compared with that of the current world average values
Refolding by High Pressure of a Toxin Containing Seven Disulfide Bonds: Bothropstoxin-1 from Bothrops jararacussu
Aggregation is a serious obstacle for recovery of biologically active heterologous proteins from inclusion bodies (IBs) produced by recombinant bacteria. E. coli transformed with a vector containing the cDNA for Bothropstoxin-1 (BthTx-1) expressed the recombinant product as IBs. In order to obtain the native toxin, insoluble and aggregated protein was refolded using high hydrostatic pressure (HHP). IBs were dissolved and refolded (2Â kbar, 16Â h), and the effects of protein concentration, as well as changes in ratio and concentration of oxido-shuffling reagents, guanidine hydrochloride (GdnHCl), and pH in the refolding buffer, were assayed. A 32% yield (7.6Â mg per liter of bacterial culture) in refolding of the native BthTx-1 was obtained using optimal conditions of the refolding buffer (TrisâHCl buffer, pH 7.5, containing 3Â mM of a 2:3 ratio of GSH/GSSG, and 1Â M GdnHCl). Scanning electron microscopy (SEM) showed that that disaggregation of part of IBs particles occurred upon compression and that the morphology of the remaining IBs, spherical particles, was not substantially altered. Dose-dependent cytotoxic activity of high-pressure refolded BthTx-1 was shown in C2C12 muscle cells
Collaborative Action of Brca1 and CtIP in Elimination of Covalent Modifications from Double-Strand Breaks to Facilitate Subsequent Break Repair
Topoisomerase inhibitors such as camptothecin and etoposide are used as anti-cancer drugs and induce double-strand breaks (DSBs) in genomic DNA in cycling cells. These DSBs are often covalently bound with polypeptides at the 3âČ and 5âČ ends. Such modifications must be eliminated before DSB repair can take place, but it remains elusive which nucleases are involved in this process. Previous studies show that CtIP plays a critical role in the generation of 3âČ single-strand overhang at âcleanâ DSBs, thus initiating homologous recombination (HR)âdependent DSB repair. To analyze the function of CtIP in detail, we conditionally disrupted the CtIP gene in the chicken DT40 cell line. We found that CtIP is essential for cellular proliferation as well as for the formation of 3âČ single-strand overhang, similar to what is observed in DT40 cells deficient in the Mre11/Rad50/Nbs1 complex. We also generated DT40 cell line harboring CtIP with an alanine substitution at residue Ser332, which is required for interaction with BRCA1. Although the resulting CtIPS332A/â/â cells exhibited accumulation of RPA and Rad51 upon DNA damage, and were proficient in HR, they showed a marked hypersensitivity to camptothecin and etoposide in comparison with CtIP+/â/â cells. Finally, CtIPS332A/â/âBRCA1â/â and CtIP+/â/âBRCA1â/â showed similar sensitivities to these reagents. Taken together, our data indicate that, in addition to its function in HR, CtIP plays a role in cellular tolerance to topoisomerase inhibitors. We propose that the BRCA1-CtIP complex plays a role in the nuclease-mediated elimination of oligonucleotides covalently bound to polypeptides from DSBs, thereby facilitating subsequent DSB repair
Ovotoxic Effects of Galactose Involve Attenuation of Follicle-Stimulating Hormone Bioactivity and Up-Regulation of Granulosa Cell p53 Expression
Clinical evidence suggests an association between galactosaemia and premature ovarian insufficiency (POI); however, the mechanism still remains unresolved. Experimental galactose toxicity in rats produces an array of ovarian dysfunction including ovarian development with deficient follicular reserve and follicular resistance to gonadotrophins that characterize the basic tenets of human POI. The present investigation explores if galactose toxicity in rats attenuates the bioactivity of gonadotrophins or interferes with their receptor competency, and accelerates the rate of follicular atresia. Pregnant rats were fed isocaloric food-pellets supplemented with or without 35% D-galactose from day-3 of gestation and continuing through weaning of the litters. The 35-day old female litters were autopsied. Serum galactose-binding capacity, galactosyltransferase (GalTase) activity, and bioactivity of FSH and LH together with their receptor competency were assessed. Ovarian follicular atresia was evaluated in situ by TUNEL. The in vitro effects of galactose were studied in isolated whole follicles in respect of generation of reactive oxygen species (ROS) and expression of caspase 3, and in isolated granulosa cells in respect of mitochondrial membrane potential, expression of p53, and apoptosis. The rats prenatally exposed to galactose exhibited significantly decreased serum GalTase activity and greater degree of galactose-incorporation capacity of sera proteins. LH biopotency and LH-FSH receptor competency were comparable between the control and study population, but the latter group showed significantly attenuated FSH bioactivity and increased rate of follicular atresia. In culture, galactose increased follicular generation of ROS and expression of caspase 3. In isolated granulosa cells, galactose disrupted mitochondrial membrane potential, stimulated p53 expression, and induced apoptosis in vitro; however co-treatment with either FSH or estradiol significantly prevented galactose-induced granulosa cell p53 expression. We conclude that the ovotoxic effects of galactose involves attenuation of FSH bioactivity that renders the ovary resistant to gonadotrophins leading to increased granulosa cell expression of p53 and follicular atresia
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