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排序方式: 共有78条查询结果,搜索用时 15 毫秒
1.
V KW Wong T Li B YK Law E DL Ma N C Yip F Michelangeli C KM Law M M Zhang K YC Lam P L Chan L Liu 《Cell death & disease》2013,4(7):e720
Autophagy is an important cellular process that controls cells in a normal homeostatic state by recycling nutrients to maintain cellular energy levels for cell survival via the turnover of proteins and damaged organelles. However, persistent activation of autophagy can lead to excessive depletion of cellular organelles and essential proteins, leading to caspase-independent autophagic cell death. As such, inducing cell death through this autophagic mechanism could be an alternative approach to the treatment of cancers. Recently, we have identified a novel autophagic inducer, saikosaponin-d (Ssd), from a medicinal plant that induces autophagy in various types of cancer cells through the formation of autophagosomes as measured by GFP-LC3 puncta formation. By computational virtual docking analysis, biochemical assays and advanced live-cell imaging techniques, Ssd was shown to increase cytosolic calcium level via direct inhibition of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase pump, leading to autophagy induction through the activation of the Ca2+/calmodulin-dependent kinase kinase–AMP-activated protein kinase–mammalian target of rapamycin pathway. In addition, Ssd treatment causes the disruption of calcium homeostasis, which induces endoplasmic reticulum stress as well as the unfolded protein responses pathway. Ssd also proved to be a potent cytotoxic agent in apoptosis-defective or apoptosis-resistant mouse embryonic fibroblast cells, which either lack caspases 3, 7 or 8 or had the Bax-Bak double knockout. These results provide a detailed understanding of the mechanism of action of Ssd, as a novel autophagic inducer, which has the potential of being developed into an anti-cancer agent for targeting apoptosis-resistant cancer cells. 相似文献
2.
Identification of positive yield QTL alleles from exotic soybean germplasm in two backcross populations 总被引:1,自引:0,他引:1
KS Kim BW Diers DL Hyten MA Rouf Mian JG Shannon RL Nelson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,125(6):1353-1369
Increasing seed yield is an important breeding goal of soybean [Glycine max (L.) Merr.] improvement efforts. Due to the small number of ancestors and subsequent breeding and selection, the genetic base of current soybean cultivars in North America is narrow. The objective of this study was to map quantitative trait loci (QTL) in two backcross populations developed using soybean plant introductions as donor parents. The first population included 116 BC(2)F(3)-derived lines developed using "Elgin" as the recurrent parent and PI 436684 as the donor parent (E population). The second population included 93 BC(3)F(3)-derived lines developed with "Williams 82" as the recurrent parent and PI 90566-1 as the donor parent (W population). The two populations were evaluated with 1,536 SNP markers and during 2?years for seed yield and other agronomic traits. Genotypic and phenotypic data were analyzed using the programs MapQTL and QTLNetwork to identify major QTL and epistatic QTL. In the E population, two yield QTL were identified by both MapQTL and QTLNetwork, and the PI 436684 alleles were associated with yield increases. In the W population, a QTL allele from PI 90566-1 accounted for 30?% of the yield variation; however, the PI region was also associated with later maturity and shorter plant height. No epistasis for seed yield was identified in either population. No yield QTL was previously reported at the regions where these QTL map indicating that exotic germplasm can be a source of new alleles that can improve soybean yield. 相似文献
3.
The contractile basis of amoeboid movement: V. The control of gelation, solation, and contraction in extracts from dictyostelium discoideum 总被引:7,自引:22,他引:7 下载免费PDF全文
Motile extracts have been prepared from Dictyostelium discoideum by homogenization and differential centrifugation at 4 degrees C in a stabilization solution (60). These extracts gelled on warming to 25 degrees Celsius and contracted in response to micromolar Ca++ or a pH in excess of 7.0. Optimal gelation occurred in a solution containing 2.5 mM ethylene glycol-bis (β-aminoethyl ether)N,N,N',N'-tetraacetate (EGTA), 2.5 mM piperazine-N-N'-bis [2-ethane sulfonic acid] (PIPES), 1 mM MgC1(2), 1 mM ATP, and 20 mM KCI at ph 7.0 (relaxation solution), while micromolar levels of Ca++ inhibited gelation. Conditions that solated the gel elicited contraction of extracts containing myosin. This was true regardless of whether chemical (micromolar Ca++, pH >7.0, cytochalasin B, elevated concentrations of KCI, MgC1(2), and sucrose) or physical (pressure, mechanical stress, and cold) means were used to induce solation. Myosin was definitely required for contraction. During Ca++-or pH-elicited contraction: (a) actin, myosin, and a 95,000-dalton polypeptide were concentrated in the contracted extract; (b) the gelation activity was recovered in the material sqeezed out the contracting extract;(c) electron microscopy demonstrated that the number of free, recognizable F-actin filaments increased; (d) the actomyosin MgATPase activity was stimulated by 4- to 10-fold. In the absense of myosin the Dictyostelium extract did not contract, while gelation proceeded normally. During solation of the gel in the absense of myosin: (a) electron microscopy demonstrated that the number of free, recognizable F- actin filaments increased; (b) solation-dependent contraction of the extract and the Ca++-stimulated MgATPase activity were reconstituted by adding puried Dictyostelium myosin. Actin purified from the Dictyostelium extract did not gel (at 2 mg/ml), while low concentrations of actin (0.7-2 mg/ml) that contained several contaminating components underwent rapid Ca++ regulated gelation. These results indicated : (a) gelation in Dictyostelium extracts involves a specific Ca++-sensitive interaction between actin and several other components; (b) myosin is an absolute requirement for contraction of the extract; (c) actin-myosin interactions capable of producing force for movement are prevented in the gel, while solation of the gel by either physical or chemical means results in the release of F-actin capable of interaction with myosin and subsequent contraction. The effectiveness of physical agents in producting contraction suggests that the regulation of contraction by the gel is structural in nature. 相似文献
4.
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6.
KS Kim JR Unfried DL Hyten RD Frederick GL Hartman RL Nelson Q Song BW Diers 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,125(6):1339-1352
Soybean rust (SBR), caused by Phakopsora pachyrhizi Sydow, is one of the most economically important and destructive diseases of soybean [Glycine max (L.) Merr.] and the discovery of novel SBR resistance genes is needed because of virulence diversity in the pathogen. The objectives of this research were to map SBR resistance in plant introduction (PI) 561356 and to identify single nucleotide polymorphism (SNP) haplotypes within the region on soybean chromosome 18 where the SBR resistance gene Rpp1 maps. One-hundred F(2:3) lines derived from a cross between PI 561356 and the susceptible experimental line LD02-4485 were genotyped with genetic markers and phenotyped for resistance to P. pachyrhizi isolate ZM01-1. The segregation ratio of reddish brown versus tan lesion type in the population supported that resistance was controlled by a single dominant gene. The gene was mapped to a 1-cM region on soybean chromosome 18 corresponding to the same interval as Rpp1. A haplotype analysis of diverse germplasm across a 213-kb interval that included Rpp1 revealed 21 distinct haplotypes of which 4 were present among 5 SBR resistance sources that have a resistance gene in the Rpp1 region. Four major North American soybean ancestors belong to the same SNP haplotype as PI 561356 and seven belong to the same haplotype as PI 594538A, the Rpp1-b source. There were no North American soybean ancestors belonging to the SNP haplotypes found in PI 200492, the source of Rpp1, or PI 587886 and PI 587880A, additional sources with SBR resistance mapping to the Rpp1 region. 相似文献
7.
’Forrest’ resistance to the soybean cyst nematode is bigenic: saturation mapping of the Rhg1and Rhg4 loci 总被引:1,自引:0,他引:1
K. Meksem P. Pantazopoulos V.N. Njiti L.D. Hyten P. R. Arelli D. A. Lightfoot 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(5):710-717
Field resistance to cyst nematode (SCN) race 3 (Heterodera glycines I.) in soybean [Glycine max (L.) Merr.] cv ’Forrest’ is conditioned by two QTLs: the underlying genes are presumed to include Rhg1 on linkage group G and Rhg4 on linkage group A2. A population of recombinant inbred lines (RILs) and two populations of near-isogenic lines (NILs) derived
from a cross of Forrest×Essex were used to map the loci affecting resistance to SCN. Bulked segregant analysis, with 512 AFLP
primer combinations and microsatellite markers, produced a high-density genetic map for the intervals carrying Rhg1 and Rhg4. The two QTLs involved in resistance to SCN were strongly associated with the AFLP marker EATGMCGA87 (P=0.0001, R2=24.5%) on linkage group G, and the AFLP marker ECCGMAAC405 (P=0.0001, R2 =26.2%) on linkage group A2. Two- way analysis of variance showed epistasic interaction (P=0.0001, R2 =16%) between the two loci controlling SCN resistance in Essex×Forrest recombinant inbred lines. Considering the two loci
as qualitative genes and the resistance as female index FI <5%, jointly the two loci explained over 98% of the resistance.
The locations of the two QTLs were confirmed in the NILs populations. Therefore SCN resistance in Forrest×Essex is bigenic.
High-efficiency marker-assisted selection can be performed using the markers to develop cultivars with stable resistance to
SCN.
Received: 5 November 2000 / Accepted: 23 January 2001 相似文献
8.
Two large-insert soybean genomic libraries constructed in a binary vector: applications in chromosome walking and genome wide physical mapping 总被引:7,自引:0,他引:7
K. Meksem K. Zobrist E. Ruben D. Hyten T. Quanzhou H-B. Zhang D. A. Lightfoot 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(5-6):747-755
Large DNA insert libraries in binary T-DNA vectors can assist in the isolation of the gene(s) underlying a quantitative trait
locus (QTL). Binary vectors facilitate the transfer of large-insert DNA fragments containing a QTL from E. coli to Agrobacterium sp. and then to plants. We constructed two soybean large-insert libraries from cv. Forrest in the pCLD04541 (V41) binary
vector after partial digestion of genomic high-molecular-weight DNA with BamHI or HindIII. The libraries contain 76,800 clones with an average insert size of 125 kb, and therefore represent 9.5-fold haploid
genome equivalents. Colony hybridization using a chloroplast-specific probe infers that the libraries contain less than 0.5%
clones of chloroplast DNA origin. These two libraries have provided clones for physical mapping of the soybean genome and
for isolation of a number of disease resistance genes. One microsatellite marker was identified from the clone that hybridized
to the Bng122 RFLP probe. The sequence-tagged site was used for genetic mapping and marker-assisted selection for genes underlying
resistance to the soybean cyst nematode and sudden death syndrome.
Received: 7 May 1999 / Accepted: 18 February 2000 相似文献
9.
Mapping soybean aphid resistance genes in PI 567598B 总被引:1,自引:0,他引:1
Carmille Bales Guorong Zhang Menghan Liu Clarice Mensah Cuihua Gu Qijian Song David Hyten Perry Cregan Dechun Wang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(8):2081-2091
The soybean aphid (Aphis glycines Matsumura) has been a major pest of soybean [Glycine max (L.) Merr.] in North America since it was first reported in 2000. Our previous study revealed that the strong aphid resistance of plant introduction (PI) 567598B was controlled by two recessive genes. The objective of this study was to locate these two genes on the soybean genetic linkage map using molecular markers. A mapping population of 282 F4:5 lines derived from IA2070 × E06902 was evaluated for aphid resistance in a field trial in 2009 and a greenhouse trial in 2010. Two quantitative trait loci (QTLs) were identified using the composite and multiple interval mapping methods, and were mapped on chromosomes 7 (linkage group M) and 16 (linkage group J), respectively. E06902, a parent derived from PI 567598B, conferred resistance at both loci. In the 2010 greenhouse trial, each of the two QTLs explained over 30 % of the phenotypic variation. Significant epistatic interaction was also found between these two QTLs. However, in the 2009 field trial, only the QTL on chromosome 16 was found and it explained 56.1 % of the phenotypic variation. These two QTLs and their interaction were confirmed with another population consisting of 94 F2:5 lines in the 2008 and 2009 greenhouse trials. For both trials in the alternative population, these two loci explained about 50 and 80.4 % of the total phenotypic variation, respectively. Our study shows that soybean aphid isolate used in the 2009 field trial defeated the QTL found on chromosome 7. Presence of the QTL on chromosome 16 conferred soybean aphid resistance in all trials. The markers linked to the aphid-resistant QTLs in PI 567598B or its derived lines can be used in marker-assisted breeding for aphid resistance. 相似文献
10.
High rate of DNA loss in the Drosophila melanogaster and Drosophila virilis species groups 总被引:3,自引:3,他引:3
We recently proposed that patterns of evolution of non-LTR
retrotransposable elements can be used to study patterns of spontaneous
mutation. Transposition of non-LTR retrotransposable elements commonly
results in creation of 5' truncated, "dead-on-arrival" copies. These
inactive copies are effectively pseudogenes and, according to the neutral
theory, their molecular evolution ought to reflect rates and patterns of
spontaneous mutation. Maximum parsimony can be used to separate the
evolution of active lineages of a non-LTR element from the fate of the
"dead-on-arrival" insertions and to directly assess the relative
frequencies of different types of spontaneous mutations. We applied this
approach using a non-LTR element, Helena, in the Drosophila virilis group
and have demonstrated a surprisingly high incidence of large deletions and
the virtual absence of insertions. Based on these results, we suggested
that Drosophila in general may exhibit a high rate of spontaneous large
deletions and have hypothesized that such a high rate of DNA loss may help
to explain the puzzling dearth of bona fide pseudogenes in Drosophila. We
also speculated that variation in the rate of spontaneous deletion may
contribute to the divergence of genome size in different taxa by affecting
the amount of superfluous "junk" DNA such as, for example, pseudogenes or
long introns. In this paper, we extend our analysis to the D. melanogaster
subgroup, which last shared a common ancestor with the D. virilis group
approximately 40 MYA. In a different region of the same transposable
element, Helena, we demonstrate that inactive copies accumulate deletions
in species of the D. melanogaster subgroup at a rate very similar to that
of the D. virilis group. These results strongly suggest that the high rate
of DNA loss is a general feature of Drosophila and not a peculiar property
of a particular stretch of DNA in a particular species group.
相似文献