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141.
CHROMagar has been reported to be useful for the rapid and accurate identification of Candida species. We tested 135 isolates of Candida species isolated from oropharyngeal candidiasis in HIV patients and found that it was useful in the presumptive identification
of Candida albicans and Candida krusei. Occasional strains of C. tropicalis produced colonies with a greenish tinge making it difficult to differentiate from C. albicans. 相似文献
142.
Watanabe S Kobayashi T Saito M Sato M Nimura-Matsune K Chibazakura T Taketani S Nakamoto H Yoshikawa H 《Biochemical and biophysical research communications》2007,352(1):36-41
In cyanobacterium Synechococcus elongatus PCC 7942, we observed that htpG-overexpression caused remarkable growth inhibition. In addition, subcellular fractionation experiments showed that HtpG was localized in the membrane fraction. To understand its function in cyanobacteria, we carried out yeast two-hybrid screening to identify specific proteins interacting with HtpG, and found out, HemE, uroporphyrinogen decarboxylase. When compared to the wild-type strain, the htpG-null mutant and -overexpressing strains exhibited higher and lower cytosolic HemE activity, based on the coproporphyrin production, respectively. These results strongly suggest that HtpG is involved in the regulation of tetrapyrrole biosynthesis through interacting with HemE protein. 相似文献
143.
Varisa Pongrakhananon Ubonthip Nimmannit Sudjit Luanpitpong Yon Rojanasakul Pithi Chanvorachote 《Apoptosis : an international journal on programmed cell death》2010,15(5):574-585
Anoikis, an apoptosis triggered by loss of cell anchorage, has been shown to be a principal mechanism of inhibition of tumor
metastasis. Recently, anti-apoptotic Bcl-2 and Cav-1 proteins have been demonstrated to be highly associated with tumor metastasis
and apoptosis resistance. Curcumin, a major active component of turmeric, Curcuma longa, has been shown to inhibit neoplastic evolution and tumor progression; however, the underlying mechanisms are unclear. In
this study, we investigated the effect of curcumin on cell anoikis as a possible mechanism of anti-tumorigenic action of curcumin,
and evaluated the potential role of Bcl-2 and Cav-1 in this process. Our results showed that ectopic expression of either
Bcl-2 or Cav-1 induced anoikis resistance of lung carcinoma H460 cells. Curcumin downregulated Bcl-2 protein during anoikis
and sensitized the cells to detachment-induced apoptosis, whereas it had no significant effect on Cav-1 protein expression.
Bcl-2 down-regulation as well as anoikis enhancement by curcumin were inhibited by superoxide anion scavenger, Mn(III)tetrakis(4-benzoic
acid) porphyrin chloride, but were unaffected by other ROS scavengers including catalase and deferoxamine, suggesting that
superoxide anion is a key player in the downregulation of Bcl-2 by curcumin. Furthermore, we provided evidence that curcumin
decreased Bcl-2 level through ubiquitin-proteasomal degradation which sensitized cells to detachment-induced apoptosis. These
findings indicate a novel pathway for curcumin regulation of Bcl-2 and provide a key mechanism of anoikis regulation that
may be exploited for metastatic cancer treatment. 相似文献
144.
145.
To investigate the evolutionary history of mesoderm in the bilaterian lineage, we are studying mesoderm development in the
polychaete annelid, Capitella sp. I, a representative lophotrochozoan. In this study, we focus on the Twist and Snail families as candidate mesodermal
patterning genes and report the isolation and in situ expression patterns of two twist homologs (CapI-twt1 and CapI-twt2) and two snail homologs (CapI-sna1 and CapI-sna2) in Capitella sp. I. CapI-twt1 is expressed in a subset of mesoderm derivatives during larval development, while CapI-twt2 shows more general mesoderm expression at the same stages. Neither twist gene is detected before the completion of gastrulation. The two snail genes have very distinct expression patterns. At cleavage and early gastrula stages, CapI-sna1 is broadly expressed in precursors of all three germ layers and becomes restricted to cells around the closing blastopore
during late gastrulation; CapI-sna2 expression is not detected at these stages. After gastrulation, both snail genes are expressed in the developing central nervous system (CNS) at stages when neural precursor cells are internalized,
and CapI-sna1 is also expressed laterally within the segmental mesoderm. Based on the expression patterns in this study, we suggest a putative
function for Capitella sp. I twist genes in mesoderm differentiation and for snail genes in regulating CNS development and general cell migration during gastrulation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
146.
Replicate harvest simulations were conducted in a large natural population of Panax quinquefolius L.␣(Araliaceae) to determine the selective effects of harvest. We investigated how minimum size requirements and the influence
of size on apparency to human harvesters could result in preferential removal of large plants. To determine which plants were
encountered in the large population, harvesters were tracked using GPS as they searched for every legally harvestable, adult
plant they could find. Plants were assigned stage-specific fitness measures based on their contributions to population growth
rate (λ) under three demographically based harvest regimes: no harvest, harvest and harvest removing seeds. Plant size was
codified into a size-index equal to the product of total leaf area and stem height. Heterogeneity of slopes was tested to
determine if the selection gradients (β) describing the relationship between fitness and size varied among the three harvest
regimes. Harvest differentially reduced the fitness of larger plants in one of four individual harvest simulations. The combined
harvest simulation significantly altered the selection regime for size in the population of juvenile and adult (harvestable)
plants. Seed removal by harvesters intensified fitness declines for larger plants. Because larger plants contribute most to
population growth, the selective effects of harvest could result in a shift in the evolutionary dynamics of this species with
significant conservation implications. 相似文献
147.
Akira C. Saito Toshihiko Ogura Kei Fujiwara Satoshi Murata Shin-ichiro M. Nomura 《PloS one》2014,9(9)
Here, we report a method for introducing large objects of up to a micrometer in diameter into cultured mammalian cells by electrofusion of giant unilamellar vesicles. We prepared GUVs containing various artificial objects using a water-in-oil (w/o) emulsion centrifugation method. GUVs and dispersed HeLa cells were exposed to an alternating current (AC) field to induce a linear cell–GUV alignment, and then a direct current (DC) pulse was applied to facilitate transient electrofusion. With uniformly sized fluorescent beads as size indexes, we successfully and efficiently introduced beads of 1 µm in diameter into living cells along with a plasmid mammalian expression vector. Our electrofusion did not affect cell viability. After the electrofusion, cells proliferated normally until confluence was reached, and the introduced fluorescent beads were inherited during cell division. Analysis by both confocal microscopy and flow cytometry supported these findings. As an alternative approach, we also introduced a designed nanostructure (DNA origami) into live cells. The results we report here represent a milestone for designing artificial symbiosis of functionally active objects (such as micro-machines) in living cells. Moreover, our technique can be used for drug delivery, tissue engineering, and cell manipulation. 相似文献
148.
Adrian Ares Constance A. Harrington Thomas A. Terry Joseph M. Kraft 《Trees - Structure and Function》2008,22(5):603-609
The stable carbon (C) composition of tree rings expressed as δ13C, is a measure of intrinsic water-use efficiency and can indicate the occurrence of past water shortages for tree growth.
We examined δ13C in 3- to 5-year-old rings of Douglas-fir (Pseudotsuga menziesii (Mirb) Franco) trees to elucidate if decreased water supply or uptake was a critical factor in the observed growth reduction
of trees competing with understory herb and shrub vegetation compared to those growing without competition. We hypothesized
that there would be no differences in δ13C of earlywood in trees growing in plots with competing vegetation and those in plots receiving complete vegetation control
during 5 years because earlywood formed early in the growing season when soil water was ample. We also hypothesized that δ13C in latewood which was formed during the later half of the growing season when precipitation was low, would be greater (less
negative) in trees in plots without vegetation control. We then separated early and latewood from rings for three consecutive
years and analyzed their δ13C composition. No significant differences in earlywood δ13C in years 3–5 were observed for trees in the two vegetation control treatments. δ13C of untreated latewood separated from wood cores was greater in 4- and 5-year-old rings of trees growing with competing vegetation
compared to trees growing without vegetation competition (i.e., −25.5 vs. −26.3‰ for year 4, and −26.1 vs. −26.8‰ for year
5). Results suggest that water shortages occurred in Douglas-fir trees on this coastal Washington site in the latewood-forming
portion of the growing season of years 4 and 5 in the no-vegetation control treatment. We also compared δ13C from untreated wood, crude cellulose extracted with the Diglyme–HCl method, and holocellulose extracted with toluene–ethanol
to see if the extraction method would increase the sensitivity of the analysis. δ13C values from the two extraction methods were highly correlated with those from untreated samples (r
2 = 0.97, 0.98, respectively). Therefore, using untreated wood would be as effective as using crude cellulose or holocellulose
to investigate δ13C patterns in young Douglas-fir. 相似文献
149.
Jian-Ping Liu Xiang Zhai Ling-Ling Wang Hong-Ju Li Fang Xie Qi Lin Sheng-Xuan Xia 《Plasmonics (Norwell, Mass.)》2016,11(3):703-711
A graphene-based cylindrical hybrid surface plasmon polariton waveguide, composed of a silicon nanowire core surrounded by a silica layer and then a graphene layer, is investigated using the finite-difference time-domain method. The analytical solutions and the numerical simulation show that an ultra-small mode area and a large propagation length can be achieved with this waveguide. Utilizing the perturbation theory of coupled mode, we demonstrate that the six lowest-order coupling modes originate from the coupling of the three lowest-order single-waveguide modes, and the m?=?1 order yy-coupling mode possesses the maximum coupling length and the minimum crosstalk. This waveguide can be used for photonic integrated circuits in the mid-infrared range. 相似文献
150.