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921.
922.
A cadherin-like protein has been identified as a putative receptor for Bacillus thuringiensis (Bt) Cry1Ac toxin in Helicoverpa armigera and plays a key role in Bt insecticidal action. In this study, we produced a fragment from this H. armigera Cry1Ac toxin-binding cadherin that included the predicted toxin-binding region. Binding of Cry1Ac toxin to this cadherin fragment facilitated the formation of a 250-kDa toxin oligomer. The cadherin fragment was evaluated for its effect on Cry1Ac toxin-binding and toxicity by ligand blotting, binding assays, and bioassays. The results of ligand blotting and binding assays revealed that the binding of Cry1Ac to H. armigera midgut epithelial cells was reduced under denaturing or native conditions in vitro. Bioassay results indicated that toxicities from Cry1Ac protoxin or activated toxin were reduced in vivo by the H. armigera cadherin fragment. The addition of the cadherin fragment had no effect on Cry2Ab toxicity. 相似文献
923.
Montalvo-Ortiz BL Castillo-Pichardo L Hernández E Humphries-Bickley T De la Mota-Peynado A Cubano LA Vlaar CP Dharmawardhane S 《The Journal of biological chemistry》2012,287(16):13228-13238
The Rho GTPase Rac regulates actin cytoskeleton reorganization to form cell surface extensions (lamellipodia) required for cell migration/invasion during cancer metastasis. Rac hyperactivation and overexpression are associated with aggressive cancers; thus, interference of the interaction of Rac with its direct upstream activators, guanine nucleotide exchange factors (GEFs), is a viable strategy for inhibiting Rac activity. We synthesized EHop-016, a novel inhibitor of Rac activity, based on the structure of the established Rac/Rac GEF inhibitor NSC23766. Herein, we demonstrate that EHop-016 inhibits Rac activity in the MDA-MB-435 metastatic cancer cells that overexpress Rac and exhibits high endogenous Rac activity. The IC(50) of 1.1 μM for Rac inhibition by EHop-016 is ~100-fold lower than for NSC23766. EHop-016 is specific for Rac1 and Rac3 at concentrations of ≤5 μM. At higher concentrations, EHop-016 inhibits the close homolog Cdc42. In MDA-MB-435 cells that demonstrate high active levels of the Rac GEF Vav2, EHop-016 inhibits the association of Vav2 with a nucleotide-free Rac1(G15A), which has a high affinity for activated GEFs. EHop-016 also inhibits the Rac activity of MDA-MB-231 metastatic breast cancer cells and reduces Rac-directed lamellipodia formation in both cell lines. EHop-016 decreases Rac downstream effects of PAK1 (p21-activated kinase 1) activity and directed migration of metastatic cancer cells. Moreover, at effective concentrations (<5 μM), EHop-016 does not affect the viability of transformed mammary epithelial cells (MCF-10A) and reduces viability of MDA-MB-435 cells by only 20%. Therefore, EHop-016 holds promise as a targeted therapeutic agent for the treatment of metastatic cancers with high Rac activity. 相似文献
924.
Testosterone (T) is generally theorized within a trade-off framework that contrasts parenting and low T with competitive challenges and high T. Paradoxically, baby cues increase T, prompting questions of whether T or its behavioral expression has been mischaracterized. We tested 55 men using a novel interactive infant doll paradigm, and results supported our hypotheses: We showed for the first time that baby cries do decrease T in men, but only when coupled with nurturant responses. In contrast, baby cries uncoupled from nurturant responses increased T. These findings highlight the need to partition infant cues and interactions into nurturant versus competitive-related contexts to more accurately conceptualize T, as per the Steroid/Peptide Theory of Social Bonds. This experiment also supports the utility of this paradigm for studying effects of infant interactions on hormonal responses, which may provide critical insights into ameliorating the darker sides of caregiving (e.g. anger, frustration, violence) and enhancing the positive sides (e.g. intimacy, nurturance, reward). 相似文献
925.
Mellone N. Marchong Christine Yurkowski Clement Ma Clarellen Spencer Sanja Pajovic Brenda L. Gallie 《PLoS genetics》2010,6(4)
CDH11 gene copy number and expression are frequently lost in human retinoblastomas and in retinoblastomas arising in TAg-RB mice. To determine the effect of Cdh11 loss in tumorigenesis, we crossed Cdh11 null mice with TAg-RB mice. Loss of Cdh11 had no gross morphological effect on the developing retina of Cdh11 knockout mice, but led to larger retinal volumes in mice crossed with TAg-RB mice (p = 0.01). Mice null for Cdh11 presented with fewer TAg-positive cells at postnatal day 8 (PND8) (p = 0.01) and had fewer multifocal tumors at PND28 (p = 0.016), compared to mice with normal Cdh11 alleles. However, tumor growth was faster in Cdh11-null mice between PND8 and PND84 (p = 0.003). In tumors of Cdh11-null mice, cell death was decreased 5- to 10-fold (p<0.03 for all markers), while proliferation in vivo remained unaffected (p = 0.121). Activated caspase-3 was significantly decreased and β-catenin expression increased in Cdh11 knockdown experiments in vitro. These data suggest that Cdh11 displays tumor suppressor properties in vivo and in vitro in murine retinoblastoma through promotion of cell death. 相似文献
926.
927.
Brenda E Groen Ellen Smulders Jacques Duysens Wim van Lankveld Vivian Weerdesteyn 《BMC research notes》2010,3(1):111
Background
Osteoporosis is a well-established risk factor for fall-related hip fractures. Training fall arrest strategies, such as martial arts (MA) fall techniques, might be useful to prevent hip fractures in persons with osteoporosis, provided that the training itself is safe. This study was conducted to determine whether MA fall training would be safe for persons with osteoporosis extrapolated from the data of young adults and using stringent safety criteria.Methods
Young adults performed sideways and forward MA falls from a kneeling position on both a judo mat and a mattress as well as from a standing position on a mattress. Hip impact forces and kinematic data were collected. For each condition, the highest hip impact force was compared with two safety criteria based on the femoral fracture load and the use of a hip protector.Results
The highest hip impact force during the various fall conditions ranged between 1426 N and 3132 N. Sideways falls from a kneeling and standing position met the safety criteria if performed on the mattress (max 1426 N and 2012 N, respectively) but not if the falls from a kneeling position were performed on the judo mat (max 2219 N). Forward falls only met the safety criteria if performed from a kneeling position on the mattress (max 2006 N). Hence, forward falls from kneeling position on a judo mat (max 2474 N) and forward falls from standing position on the mattress (max 3132 N) did not meet both safety criteria.Conclusions
Based on the data of young adults and safety criteria, the MA fall training was expected to be safe for persons with osteoporosis if appropriate safety measures are taken: during the training persons with osteoporosis should wear hip protectors that could attenuate the maximum hip impact force by at least 65%, perform the fall exercises on a thick mattress, and avoid forward fall exercises from a standing position. Hence, a modified MA fall training might be useful to reduce hip fracture risk in persons with osteoporosis.928.
Durán A Gryzenhout M Drenth A Slippers B Ahumada R Wingfield BD Wingfield MJ 《Fungal biology》2010,114(9):746-752
Phytophthora pinifolia is the causal agent of the recently discovered needle disease of Pinus radiata in Chile, referred to as “Daño Foliar del Pino” (DFP). The genetic structure of the pathogen population is unknown, which hinders our understanding of its appearance and spread in Chile since 2004. In this study, a population of 88 cultures of P. pinifolia isolated from P. radiata at several localities in Chile was evaluated for genotypic diversity using amplified fragment length polymorphisms (AFLPs). Results of the AFLP analyses showed that the P. pinifolia population in Chile consists of two near identical genotypes but with no genetic differentiation based on geography, year of isolation or the part of the tree from which the isolates were obtained. Mating experiments did not lead to the production of gametangia suggesting that the organism is sterile. The fact that a single clonal genotype dominates the population of P. pinifolia in Chile supports the hypothesis that P. pinifolia was recently introduced into this country and that its impact is due to a new and susceptible host encounter. 相似文献
929.
930.
Carl J. Yeoman Suleyman Yildirim Susan M. Thomas A. Scott Durkin Manolito Torralba Granger Sutton Christian J. Buhay Yan Ding Shannon P. Dugan-Rocha Donna M. Muzny Xiang Qin Richard A. Gibbs Steven R. Leigh Rebecca Stumpf Bryan A. White Sarah K. Highlander Karen E. Nelson Brenda A. Wilson 《PloS one》2010,5(8)