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101.
Dakin LA Block MH Chen H Code E Dowling JE Feng X Ferguson AD Green I Hird AW Howard T Keeton EK Lamb ML Lyne PD Pollard H Read J Wu AJ Zhang T Zheng X 《Bioorganic & medicinal chemistry letters》2012,22(14):4599-4604
Novel substituted benzylidene-1,3-thiazolidine-2,4-diones (TZDs) have been identified as potent and highly selective inhibitors of the PIM kinases. The synthesis and SAR of these compounds are described, along with X-ray crystallographic, anti-proliferative, and selectivity data. 相似文献
102.
Wu D Sullards MC Oldham CD Gelbaum L Lucrezi J Pullman GS May SW 《The New phytologist》2012,193(2):313-326
? Myo-inositol hexakisphosphate (InsP(6)), abundant in animals and plants, is well known for its anticancer activity. However, many aspects of InsP(6) function in plants remain undefined. We now report the first evidence that InsP(6) can inhibit cellular proliferation in plants under growth conditions where phosphorus is not limited. ? A highly anionic molecule inhibitory to early-stage somatic embryo growth of loblolly pine (LP) was purified chromatographically from late-stage LP female gametophytes (FGs), and then characterized structurally using mass spectrometry (MS) and nuclear magnetic resonance (NMR) analyses. ? Exact mass and mass spectrometry-mass spectrometry (MS-MS) fragmentation identified the bioactive molecule as an inositol hexakisphosphate. It was then identified as the myo-isomer (i.e. InsP(6)) on the basis of (1)H-, (31)P- and (13)C-NMR, (1)H-(1)H correlation spectroscopy (COSY), (1)H-(31)P heteronuclear single quantum correlation (HSQC) and (1)H-(13)C HSQC. Topical application of InsP(6) to early-stage somatic embryos indeed inhibits embryonic growth. ? Recently evidence has begun to emerge that InsP(6) may also play a regulatory role in plant cells. We anticipate that our findings will help to stimulate additional investigations aimed at elucidating the roles of inositol phosphates in cellular growth and development in plants. 相似文献
103.
Respiratory syncytial virus G protein and G protein CX3C motif adversely affect CX3CR1+ T cell responses 总被引:6,自引:0,他引:6
Harcourt J Alvarez R Jones LP Henderson C Anderson LJ Tripp RA 《Journal of immunology (Baltimore, Md. : 1950)》2006,176(3):1600-1608
Interactions between fractalkine (CX3CL1) and its receptor, CX3CR1, mediate leukocyte adhesion, activation, and trafficking. The respiratory syncytial virus (RSV) G protein has a CX3C chemokine motif that can bind CX3CR1 and modify CXCL1-mediated responses. In this study, we show that expression of the RSV G protein or the G protein CX3C motif during infection is associated with reduced CX3CR1+ T cell trafficking to the lung, reduced frequencies of RSV-specific, MHC class I-restricted IFN-gamma-expressing cells, and lower numbers of IL-4- and CX3CL1-expressing cells. In addition, we show that CX3CR1+ cells constitute a major component of the cytotoxic response to RSV infection. These results suggest that G protein and the G protein CX3C motif reduce the antiviral T cell response to RSV infection. 相似文献
104.
We examined fossil chironomids (Diptera: Chironomidae) in the surface sediments of four maar lakes in western Alaska to determine
chironomid distribution patterns with respect to within-lake gradients of water depth, LOI (loss-on-ignition), and bottom-water
temperature. Linear and non-linear regressions were undertaken to test whether the within-lake distributions of fossil chironomids
were uniform. Additionally, water depths where abrupt changes or breakpoints in the assemblages occur were identified using
piecewise regression. Direct gradient analysis was then used to examine variation in the assemblages explained by the environmental
data. For the shallowest lake, chironomid abundances of individual taxa and inferred temperatures varied little within the
lake. For the three deep lakes, seven of the sixteen commonest fossil taxa varied significantly with water depth, although
some lake-specific patterns were evident. Water depth was generally identified as the principal environmental variable in
explaining variation in the assemblages, although sediment organic matter content and bottom-water temperature were also important.
Abrupt changes in assemblages occurred at different water depths in each lake, and at only one lake did the breakpoint occur
within the range of water depths defining the thermocline. Chironomid-inferred temperature trends from the lakes also showed
depth-related patterns: the warmest inferred temperatures were generally from both the shallowest and deepest water depths,
whereas intermediate depths yielded temperature inferences about 0.5 to 1.0°C cooler than the average within-lake value. Nevertheless,
we conclude that these patterns had only a slight impact on temperature reconstructions relative to the prediction error of
the model. A greater understanding of taphonomic processes is needed to determine their influence on environmental reconstructions
based on chironomids.
Handling editor: J. Saros 相似文献
105.
Hayfa Salman Jaroslav Blazek Amparo Lopez-Rubio Elliot P. Gilbert Tracey Hanley Les Copeland 《Carbohydrate polymers》2009,75(3):420-427
Five wheat (Triticum aestivum L.) starches, from the varieties Sunco, Sunsoft, SM1118, and SM1028, with similar amylose content, and a waxy wheat were separated into large (A) and small (B) granules. The unfractionated starches, and isolated A and B granules, were characterized structurally and evaluated for their functional properties. The amylopectin chain length distribution revealed that A granules had a lower proportion of short chains with degree of polymerization (DP) 6-12 and a higher proportion of chains with DP 25-36 than B granules. X-ray diffraction (XRD) patterns showed predominantly A-type crystallinity for all of the starches. No differences in the crystallinity were found between unfractionated, A and B granules. Small-angle X-ray scattering (SAXS) patterns of the starches at 55% hydration showed that the lamellar repeat distance in A granules was larger than that of B granules for all the starches examined. However, the lamellar distances of both A and B granules from the waxy wheat were smaller than those of Sunco, Sunsoft, SM1118 and SM1028 starches. The swelling power of the B granules was greater than that of A granules from all five starches. The kinetics of digestion of A and B granules with α-amylase in vitro were complex, with B granules initially digested to a greater extent than A granules. After 4 h of incubation, A granules showed greater digestibility than B granules, except in the case of waxy starch where unfractionated and fractionated granules had similar in vitro digestibility. Correlations between structural and functional parameters were more significant for the isolated A and B granules than for the unfractionated starches. This study demonstrates that A and B granules differ in structure and functionality, and that some correlations between these properties could be masked in unfractionated starches with bimodal granule size distribution. 相似文献
106.
Jaroslav Blazek Hayfa Salman Amparo Lopez Rubio Elliot Gilbert Tracey Hanley Les Copeland 《Carbohydrate polymers》2009,75(4):705-711
Small-angle X-ray scattering (SAXS) together with several complementary techniques, such as differential scanning calorimetry and X-ray diffraction, have been employed to investigate the structural features that give diverse functional properties to wheat starches (Triticum aestivum L.) within a narrow range of enriched amylose content (36–43%). For these starches, which come from a heterogeneous genetic background, SAXS analysis of duplicate samples enabled structural information to be obtained about their lamellar architecture where differences in lamellar spacing among samples were only several tenths of nanometer. The SAXS analysis of these wheat starches with increased amylose content has shown that amylose accumulates in both crystalline and amorphous parts of the lamella. Using waxy starch as a distinctive comparison with the other samples confirmed a general trend of increasing amylose content being linked with the accumulation of defects within crystalline lamellae. We conclude that amylose content directly influences the architecture of semi-crystalline lamellae, whereas thermodynamic and functional properties are brought about by the interplay of amylose content and amylopectin architecture. 相似文献
107.
Supatra Porasuphatana Guan-Liang Cao Pei Tsai Fatemeh Tavakkoli Theresa Huwar Les Baillie Alan S. Cross Paul Shapiro Gerald M. Rosen 《Current microbiology》2010,61(6):567-573
Interactions between Bacillus anthracis (B. anthracis) and host cells are of particular interest given the implications of anthrax as a biological weapon. Inhaled B. anthracis endospores encounter alveolar macrophages as the first line of defense in the innate immune response. Yet, the consequences of this interaction remain unclear. We have demonstrated that B. anthracis uses arginase, inherent in the endospores, to reduce the ability of macrophages to produce nitric oxide (?NO) from inducible nitric oxide synthase (NOS2) by competing for l-arginine, producing l-ornithine at the expense of ?NO. In the current study, we used genetically engineered B. anthracis endospores to evaluate the contribution of germination and the lethal toxin (LT) in mediating signaling pathways responsible for the induction of NOS2 and ornithine decarboxylase (ODC), which is the rate-limiting enzyme in the conversion of l-ornithine into polyamines. We found that induction of NOS2 and ODC expression in macrophages exposed to B. anthracis occurs through the activation of p38 and ERK1/2 MAP kinases, respectively. Optimal induction of NOS2 was observed following exposure to germination-competent endospores, whereas ODC induction occurred irrespective of the endospores’ germination capabilities and was more prominent in macrophages exposed to endospores lacking LT. Our findings suggest that activation of kinase signaling cascades that determine macrophage defense responses against B. anthracis infection occurs through distinct mechanisms. 相似文献
108.
Joshua Kurek Les C. Cwynar Russ C. Weeber Dean S. Jeffries John P. Smol 《Hydrobiologia》2010,652(1):207-221
Small, shallow lakes and ponds are often the dominant landscape features in many regions, but are comparably less studied
than larger lakes. Shallow lakes are more likely to lack fish populations; however, it is often difficult to ascertain whether
these sites were naturally fishless or lost their fish populations due to anthropogenic or natural stressors. We examined
the distributional abundances of four Chaoborus species by identifying and enumerating their larval mandibles in the surface sediments of 146 randomly selected lakes from
northwestern Ontario, Canada, to determine the key environmental gradients influencing chaoborid distributions. Chaoborus mandibles were encountered at 110 lakes and, in 65% of those lakes, total counts were ≥10. Direct gradient analyses were
then used to show that lakewater total aluminum concentrations (negatively correlated with pH), lakewater sodium concentrations,
lake surface area, and maximum water depth were significant predictors of the distributional abundances of Chaoborus. Generalized linear models indicated that Chaoborus species varied in their responses to significant environmental factors. C. (Sayomyia) was not significantly associated with any environmental variable and the abundances of larger chaoborids may be an important
biotic factor affecting this taxon. Chaoborus americanus, an indicator of fishless lakes, was significantly correlated with all five key variables and demonstrated a clear threshold
of occurrence in relatively small lakes (i.e., <10 ha in surface area). Furthermore, based on the occurrence and abundance
of C. americanus, we estimated that 20% of the lakes we surveyed are currently fishless. These lakes significantly differ in several geomorphic
and water-chemistry measures compared to the other study lakes. 相似文献
109.
A proteomic approach to the identification and characterisation of protein composition in wheat germ 总被引:1,自引:0,他引:1
Mak Y Skylas DJ Willows R Connolly A Cordwell SJ Wrigley CW Sharp PJ Copeland L 《Functional & integrative genomics》2006,6(4):322-337
Proteome analyses were carried out on commercial wheat germ of mature grain from the biscuit-making wheat cultivar, Rosella. Wheat germ protein extracts were fractionated by two-dimensional gel electrophoresis across two different immobilised pH gradients: pH 4.0–7.0 and 6.0–9.0. A total of 612 individual protein spots were excised from the gels and characterised by peptide mass fingerprinting. From these analyses, 347 individual proteins were identified from protein sequence database interrogation, and 301 different types of protein were catalogued according to protein function. The remaining 265 protein spots gave poor or no matches to proteins in the databases and were not identified in this study. Six different classes of enzymes were identified in the germ, many of them having roles in the mobilisation of energy reserves for germination. Abundantly expressed enzyme classes include the oxidoreductases, transferases and hydrolases. A comparison was also made between the major protein classes expressed in the germ and protein classes expressed in the endosperm from previous proteomic work. This study contributes significantly to our knowledge of protein expression and heterogeneity in the germ of wheat grain and forms the basis for future studies in regard to the characterisation of proteins during the initial stages of germination. 相似文献
110.
Les J. Szabo 《Mycoscience》2006,47(3):130-136
Species of macrocyclic, heteroecious grass rusts often have been defined with wide host ranges and variation in spore morphology.
Consequently, some are species complexes and contain genetically distinct forms. Molecular analyses, together with morphological
and biological methods, provide powerful means to dissect these complexes. Puccinia coronata is a complex species that has a broad telial host range including more than 45 genera of grasses and a narrow aecial host
range. Phylogenetic analysis of nuclear ribosomal internal transcribed spacer (ITS) DNA sequences from 15 aecial and telial
collections grouped P. coronata into six distinct clades supporting separation of this complex into four distinct species. Puccinia andropogonis, a common rust of tall prairie grasses in North America, is also a complex species. However, in contrast to P. coronata, P. andropogonis has a narrow telial host range and a broad aecial host range. DNA sequence analysis grouped 15 collections of P. andropogonis into six distinct clades representing at least four distinct species. Speciation of P. coronata appears to have occurred primarily by radiation onto new telial hosts, whereas in P. andropogonis speciation appears to have occurred primarily by radiation onto new aecial hosts. 相似文献