72 research outputs found
Market Valuations in the New Economy: An Investigation of What Has Changed
We find mixed support for the hypothesis that a “New Economy” subperiod occurred in the late 1990s in which the relation between equity value and traditional financial variables differs from previous periods. We examine a regression model of equity value on financial variables over 25 years for a broad firm sample and for firm subsamples thought to be emblematic of the New Economy. We find the regression model\u27s explanatory power declined in the New Economy subperiod for all firm subsamples. However, for all subsamples, the regression model\u27s structure during the New Economy subperiod is not unusual compared to other subperiods
Nuclear cGMP-Dependent Kinase Regulates Gene Expression via Activity-Dependent Recruitment of a Conserved Histone Deacetylase Complex
Elevation of the second messenger cGMP by nitric oxide (NO) activates the cGMP-dependent protein kinase PKG, which is key in regulating cardiovascular, intestinal, and neuronal functions in mammals. The NO-cGMP-PKG signaling pathway is also a major therapeutic target for cardiovascular and male reproductive diseases. Despite widespread effects of PKG activation, few molecular targets of PKG are known. We study how EGL-4, the Caenorhabditis elegans PKG ortholog, modulates foraging behavior and egg-laying and seeks the downstream effectors of EGL-4 activity. Using a combination of unbiased forward genetic screen and proteomic analysis, we have identified a conserved SAEG-1/SAEG-2/HDA-2 histone deacetylase complex that is specifically recruited by activated nuclear EGL-4. Gene expression profiling by microarrays revealed >40 genes that are sensitive to EGL-4 activity in a SAEG-1–dependent manner. We present evidence that EGL-4 controls egg laying via one of these genes, Y45F10C.2, which encodes a novel protein that is expressed exclusively in the uterine epithelium. Our results indicate that, in addition to cytoplasmic functions, active EGL-4/PKG acts in the nucleus via a conserved Class I histone deacetylase complex to regulate gene expression pertinent to behavioral and physiological responses to cGMP. We also identify transcriptional targets of EGL-4 that carry out discrete components of the physiological response
Getting a Head Start: Diet, Sub-Adult Growth, and Associative Learning in a Seed-Eating Passerine
Developmental stress, and individual variation in response to it, can have important fitness consequences. Here we investigated the consequences of variable dietary protein on the duration of growth and associative learning abilities of zebra finches, Taeniopygia guttata, which are obligate graminivores. The high-protein conditions that zebra finches would experience in nature when half-ripe seed is available were mimicked by the use of egg protein to supplement mature seed, which is low in protein content. Growth rates and relative body proportions of males reared either on a low-protein diet (mature seed only) or a high-protein diet (seed plus egg) were determined from body size traits (mass, head width, and tarsus) measured at three developmental stages. Birds reared on the high-protein diet were larger in all size traits at all ages, but growth rates of size traits showed no treatment effects. Relative head size of birds reared on the two diets differed from age day 95 onward, with high-diet birds having larger heads in proportion to both tarsus length and body mass. High-diet birds mastered an associative learning task in fewer bouts than those reared on the low-protein diet. In both diet treatments, amount of sub-adult head growth varied directly, and sub-adult mass change varied inversely, with performance on the learning task. Results indicate that small differences in head growth during the sub-adult period can be associated with substantial differences in adult cognitive performance. Contrary to a previous report, we found no evidence for growth compensation among birds on the low-protein diet. These results have implications for the study of vertebrate cognition, developmental stress, and growth compensation
Endocrine regulation of predator-induced phenotypic plasticity
Elucidating the developmental and genetic control of phenotypic plasticity remains a central agenda in evolutionary ecology. Here, we investigate the physiological regulation of phenotypic plasticity induced by another organism, specifically predator-induced phenotypic plasticity in the model ecological and evolutionary organism Daphnia pulex. Our research centres on using molecular tools to test among alternative mechanisms of developmental control tied to hormone titres, receptors and their timing in the life cycle. First, we synthesize detail about predator-induced defenses and the physiological regulation of arthropod somatic growth and morphology, leading to a clear prediction that morphological defences are regulated by juvenile hormone and life-history plasticity by ecdysone and juvenile hormone. We then show how a small network of genes can differentiate phenotype expression between the two primary developmental control pathways in arthropods: juvenoid and ecdysteroid hormone signalling. Then, by applying an experimental gradient of predation risk, we show dose-dependent gene expression linking predator-induced plasticity to the juvenoid hormone pathway. Our data support three conclusions: (1) the juvenoid signalling pathway regulates predator-induced phenotypic plasticity; (2) the hormone titre (ligand), rather than receptor, regulates predator-induced developmental plasticity; (3) evolution has favoured the harnessing of a major, highly conserved endocrine pathway in arthropod development to regulate the response to cues about changing environments (risk) from another organism (predator)
Hv-CBF2A overexpression in barley accelerates COR gene transcript accumulation and acquisition of freezing tolerance during cold acclimation
Abstract C-Repeat Binding Factors (CBFs) are DNAbinding
transcriptional activators of gene pathways imparting
freezing tolerance. Poaceae contain three CBF subfamilies,
two of which, HvCBF3/CBFIII and HvCBF4/CBFIV,
are unique to this taxon. To gain mechanistic insight into
HvCBF4/CBFIV CBFs we overexpressed Hv-CBF2A in
spring barley (Hordeum vulgare) cultivar ‘Golden Promise’.
The Hv-CBF2A overexpressing lines exhibited stunted
growth, poor yield, and greater freezing tolerance compared
to non-transformed ‘Golden Promise’. Differences in
freezing tolerance were apparent only upon cold acclimation.
During cold acclimation freezing tolerance of the
Hv-CBF2A overexpressing lines increased more rapidly
than that of ‘Golden Promise’ and paralleled the freezing
tolerance of the winter hardy barley ‘Dicktoo’. Transcript
levels of candidate CBF target genes, COR14B and DHN5
were increased in the overexpressor lines at warm temperatures,
and at cold temperatures they accumulated to much
higher levels in the Hv-CBF2A overexpressors than in
‘Golden Promise’. Hv-CBF2A overexpression also
increased transcript levels of other CBF genes at FROST
RESISTANCE-H2-H2 (FR-H2) possessing CRT/DRE sites
in their upstream regions, the most notable of which was
CBF12. CBF12 transcript levels exhibited a relatively constant
incremental increase above levels in ‘Golden Promise’
both at warm and cold. These data indicate that Hv-CBF2A
activates target genes at warm temperatures and that transcript
accumulation for some of these targets is greatly
enhanced by cold temperatures
Filarial Parasites Develop Faster and Reproduce Earlier in Response to Host Immune Effectors That Determine Filarial Life Expectancy
During larval development, filarial nematodes adjust their lifelong reproductive strategy to the presence of anti-parasitic immune cells that determine host resistance and experimental vaccine efficacy
Apollo Missions
While Apollo 11 may be the most famous, each of the Apollo Missions contributed significantly to space exploration. The missions prior to Apollo 11 paved the way for a successful landing and subsequent missions collected valuable scientific data to advance our understanding of our closest neighbor. This exhibit shares the stories of the manned Apollo Missions, 7-17 and demonstrates the incredible wealth of science conducted on and near the lunar surface. Here you will find details on the unique objectives and outcomes of each mission and learn how our understanding of the Moon has changed as a result.https://thekeep.eiu.edu/lib_exhibits_space2019_photos/1014/thumbnail.jp
Apollo Missions
While Apollo 11 may be the most famous, each of the Apollo Missions contributed significantly to space exploration. The missions prior to Apollo 11 paved the way for a successful landing and subsequent missions collected valuable scientific data to advance our understanding of our closest neighbor. This exhibit shares the stories of the manned Apollo Missions, 7-17 and demonstrates the incredible wealth of science conducted on and near the lunar surface. Here you will find details on the unique objectives and outcomes of each mission and learn how our understanding of the Moon has changed as a result.https://thekeep.eiu.edu/lib_exhibits_space2019_photos/1016/thumbnail.jp
Apollo
Likely the most famous space mission of all time, Apollo 11 landed the first humans on another celestial body. Millions of people around the world watched the crew of Armstrong, Aldrin, and Collins as they undertook the most daunting journey the world has known. On July 20, 1969 the world witnessed the fulfillment of President Kennedy’s promise to land an American on the Moon before the end of the decade. With strong federal backing, NASA rose to the occasion. In addition to mission details, the exhibit displays some of the most historic images from the Apollo 11 mission.https://thekeep.eiu.edu/lib_exhibits_space2019_photos/1001/thumbnail.jp
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