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123.
Julie A. Hawkins Laura White Olascoaga Colin E. Hughes José-Luis R. Contreras Jiménez Pedro Mercado Ruaro 《Plant Systematics and Evolution》1999,216(1-2):49-68
Morphometric, cytogenetic, geographical and ecological evidence for hybridization betweenParkinsonia aculeata andCercidium praecox is presented. Morphometric investigation using the character count procedure and cytogenetic observations confirm hybrid status. All diagnostic morphometric characters were intermediate in the hybrid. Both parents (2n = 28) show regular tetrad formation and pollen fertility greater than 94%. Hybrids have a chromosome number of 2n = 28 or 2n = 30, and display meiotic abnormalities including lagging chromosomes and micronucleus formation; less than 21% of hybrid pollen was fertile. Ecological and geographical information suggests that hybridization is occurring at increasing frequency due to the expanding range ofP. aculeata associated with cultivation as an ornamental, coupled with ecological disturbance and weediness, and the cultivation ofC. praecox and hybrids as fodder, ornamental and shade trees. Hybrid fertility and phenological observations, in conjunction with F-weighted principal component analysis, suggest that the progeny of F1 hybrids are established. The hybrid is formally described asP. ×carterae. 相似文献
124.
Hein I Klinger S Dooms M Flekna G Stessl B Leclercq A Hill C Allerberger F Wagner M 《Applied and environmental microbiology》2011,77(6):2169-2173
Listeria monocytogenes strains (n = 117) were screened for the presence of stress survival islet 1 (SSI-1). SSI-1(+) strains (32.5%) belonged mainly to serotypes 1/2c, 3b, and 3c. All sequence type 121 (ST-121) strains included (n = 7) possessed homologues to Listeria innocua genes lin0464 and lin0465 instead of SSI-1. 相似文献
125.
Julie E. Gleason 《Developmental biology》2010,348(1):58-66
Metazoan stem cells repopulate tissues during adult life by dividing asymmetrically to generate another stem cell and a cell that terminally differentiates. Wnt signaling regulates the division pattern of stem cells in flies and vertebrates. While the short-lived nematode C. elegans has no adult somatic stem cells, the lateral epithelial seam cells divide in a stem cell-like manner in each larval stage, usually generating a posterior daughter that retains the seam cell fate and an anterior daughter that terminally differentiates. We show that while wild-type adult animals have 16 seam cells per side, animals with reduced function of the TCF homolog POP-1 have as many as 67 seam cells, and animals with reduced function of the β-catenins SYS-1 and WRM-1 have as few as three. Analysis of seam cell division patterns showed alterations in their stem cell-like divisions in the L2-L4 stages: reduced Wnt signaling caused both daughters to adopt non-seam fates, while activated Wnt signaling caused both daughters to adopt the seam fate. Therefore, our results indicate that Wnt signaling globally regulates the asymmetric, stem cell-like division of most or all somatic seam cells during C. elegans larval development, and that Wnt pathway regulation of stem cell-like behavior is conserved in nematodes. 相似文献
126.
Sarah J. Hill Allison P. Clark Daniel P. Silver David M. Livingston 《Molecular and cellular biology》2014,34(20):3828-3842
Sporadic basal-like cancers (BLCs) are a common subtype of breast cancer that share multiple biological properties with BRCA1-mutated breast tumors. Despite being BRCA1+/+, sporadic BLCs are widely viewed as phenocopies of BRCA1-mutated breast cancers, because they are hypothesized to manifest a BRCA1 functional defect or breakdown of a pathway(s) in which BRCA1 plays a major role. The role of BRCA1 in the repair of double-strand DNA breaks by homologous recombination (HR) is its best understood function and the function most often implicated in BRCA1 breast cancer suppression. Therefore, it is suspected that sporadic BLCs exhibit a defect in HR. To test this hypothesis, multiple DNA damage repair assays focused on several types of repair were performed on a group of cell lines classified as sporadic BLCs and on controls. The sporadic BLC cell lines failed to exhibit an overt HR defect. Rather, they exhibited defects in the repair of stalled replication forks, another BRCA1 function. These results provide insight into why clinical trials of poly(ADP-ribose) polymerase (PARP) inhibitors, which require an HR defect for efficacy, have been unsuccessful in sporadic BLCs, unlike cisplatin, which elicits DNA damage that requires stalled fork repair and has shown efficacy in sporadic BLCs. 相似文献
127.
De Cotiis DA Woll MP Fox TE Hill RB Levenson R Flanagan JM 《Protein expression and purification》2008,61(2):103-112
We have developed a protocol to produce large quantities of high purity myristoylated and non-myristoylated neuronal calcium sensor 1 (NCS-1) protein. NCS-1 is a member of the neuronal calcium sensor (NCS) family and plays an important role in modulating G-protein signaling and exocytosis pathways in cells. Many of these functions are calcium-dependent and require NCS-1 to be modified with an N-terminal myristoyl moiety. In our system, a C-terminally 6x His-tagged variant of NCS-1 was co-expressed with yeast N-myristoyltransferase (NMT) in ZYP-5052 auto-induction media supplemented with sodium myristate (100-200 microM). With optimized growth conditions and a high capacity metal affinity purification scheme, >50mg of homogenous myristoylated NCS-1 is obtained from 1L of culture in a single step. The properties of the C-terminally tagged NCS-1 variants are indistinguishable from those reported for untagged NCS-1. Using this system, we have also isolated and characterized mutant NCS-1 proteins that have attenuated (NCS-1 E120Q) and abrogated (NCS-1 DeltaEF) ability to bind calcium. The large quantities of NCS-1 proteins isolated from small culture volumes of auto-inducible media will provide the necessary reagents for further biochemical and structural characterization. The affinity tag at the C-terminus of the protein provides a suitable reagent for easily identifying binding partners of the various NCS-1 constructs. Additionally, this method could be used to produce other recombinant proteins of the NCS family, and may be extended to express and isolate myristoylated variants of other proteins. 相似文献
128.
Julie M. Grossman Brendan E. O’Neill Siu Mui Tsai Biqing Liang Eduardo Neves Johannes Lehmann Janice E. Thies 《Microbial ecology》2010,60(1):192-205
We compared the microbial community composition in soils from the Brazilian Amazon with two contrasting histories; anthrosols
and their adjacent non-anthrosol soils of the same mineralogy. The anthrosols, also known as the Amazonian Dark Earths or
terra preta, were managed by the indigenous pre-Colombian Indians between 500 and 8,700 years before present and are characterized
by unusually high cation exchange capacity, phosphorus (P), and calcium (Ca) contents, and soil carbon pools that contain
a high proportion of incompletely combusted biomass as biochar or black carbon (BC). We sampled paired anthrosol and unmodified
soils from four locations in the Manaus, Brazil, region that differed in their current land use and soil type. Community DNA
was extracted from sampled soils and characterized by use of denaturing gradient gel electrophoresis (DGGE) and terminal restriction
fragment length polymorphism. DNA bands of interest from Bacteria and Archaea DGGE gels were cloned and sequenced. In cluster
analyses of the DNA fingerprints, microbial communities from the anthrosols grouped together regardless of current land use
or soil type and were distinct from those in their respective, paired adjacent soils. For the Archaea, the anthrosol communities
diverged from the adjacent soils by over 90%. A greater overall richness was observed for Bacteria sequences as compared with
those of the Archaea. Most of the sequences obtained were novel and matched those in databases at less than 98% similarity.
Several sequences obtained only from the anthrosols grouped at 93% similarity with the Verrucomicrobia, a genus commonly found in rice paddies in the tropics. Sequences closely related to Proteobacteria and Cyanobacteria sp. were recovered only from adjacent soil samples. Sequences related to Pseudomonas, Acidobacteria, and Flexibacter sp. were recovered from both anthrosols and adjacent soils. The strong similarities among the microbial communities present
in the anthrosols for both the Bacteria and Archaea suggests that the microbial community composition in these soils is controlled
more strongly by their historical soil management than by soil type or current land use. The anthrosols had consistently higher
concentrations of incompletely combusted organic black carbon material (BC), higher soil pH, and higher concentrations of
P and Ca compared to their respective adjacent soils. Such characteristics may help to explain the longevity and distinctiveness
of the anthrosols in the Amazonian landscape and guide us in recreating soils with sustained high fertility in otherwise nutrient-poor
soils in modern times. 相似文献
129.
Biswas S Nyman JS Alvarez J Chakrabarti A Ayres A Sterling J Edwards J Rana T Johnson R Perrien DS Lonning S Shyr Y Matrisian LM Mundy GR 《PloS one》2011,6(11):e27090
Breast cancer often metastasizes to bone causing osteolytic bone resorption which releases active TGFβ. Because TGFβ favors progression of breast cancer metastasis to bone, we hypothesized that treatment using anti-TGFβ antibody may reduce tumor burden and rescue tumor-associated bone loss in metastatic breast cancer. In this study we have tested the efficacy of an anti-TGFβ antibody 1D11 preventing breast cancer bone metastasis. We have used two preclinical breast cancer bone metastasis models, in which either human breast cancer cells or murine mammary tumor cells were injected in host mice via left cardiac ventricle. Using several in vivo, in vitro and ex vivo assays, we have demonstrated that anti-TGFβ antibody treatment have significantly reduced tumor burden in the bone along with a statistically significant threefold reduction in osteolytic lesion number and tenfold reduction in osteolytic lesion area. A decrease in osteoclast numbers (p?=?0.027) in vivo and osteoclastogenesis ex vivo were also observed. Most importantly, in tumor-bearing mice, anti-TGFβ treatment resulted in a twofold increase in bone volume (p<0.01). In addition, treatment with anti-TGFβ antibody increased the mineral-to-collagen ratio in vivo, a reflection of improved tissue level properties. Moreover, anti-TGFβ antibody directly increased mineralized matrix formation in calverial osteoblast (p?=?0.005), suggesting a direct beneficial role of anti-TGFβ antibody treatment on osteoblasts. Data presented here demonstrate that anti-TGFβ treatment may offer a novel therapeutic option for tumor-induced bone disease and has the dual potential for simultaneously decreasing tumor burden and rescue bone loss in breast cancer to bone metastases. This approach of intervention has the potential to reduce skeletal related events (SREs) in breast cancer survivors. 相似文献
130.
Amalia Karahalios Julie A. Simpson Laura Baglietto Robert J. MacInnis Allison M. Hodge Graham G. Giles Dallas R. English 《PloS one》2014,9(7)