The clockfront and wavefront model revisited

The currently accepted interpretation of the clock and wavefront model of somitogenesis is that a posteriorly moving molecular gradient sequentially slows the rate of clock oscillations, resulting in a spatial readout of temporal oscillations. However, while molecular components of the clocks and wavefronts have now been identified in the pre-somitic mesoderm (PSM), there is not yet conclusive evidence demonstrating that the observed molecular wavefronts act to slow clock oscillations. Here we present an alternative formulation of the clock and wavefront model in which oscillator coupling, already known to play a key role in oscillator synchronisation, plays a fundamentally important role in the slowing of oscillations along the anterior–posterior (AP) axis. Our model has three parameters which can be determined, in any given species, by the measurement of three quantities: the clock period in the posterior PSM, somite length and the length of the PSM. A travelling wavefront, which slows oscillations along the AP axis, is an emergent feature of the model. Using the model we predict: (a) the distance between moving stripes of gene expression; (b) the number of moving stripes of gene expression and (c) the oscillator period profile along the AP axis. Predictions regarding the stripe data are verified using existing zebrafish data. We simulate a range of experimental perturbations and demonstrate how the model can be used to unambiguously define a reference frame along the AP axis. Comparing data from zebrafish, chick, mouse and snake, we demonstrate that: (a) variation in patterning profiles is accounted for by a single nondimensional parameter; the ratio of coupling strengths; and (b) the period profile along the AP axis is conserved across species. Thus the model is consistent with the idea that, although the genes involved in pattern propagation in the PSM vary, there is a conserved patterning mechanism across species

Effects of Grazing Crop Residues of bt-Corn Hybrids on Performance of Pregnant Beef Cows

To determine the effects of grazing crop residues from bt-corn hybrids on performance of pregnant beef cows, one non bt-corn hybrid (Pioneer 3489) and three bt-corn hybrids (Pioneer 34RO7 and Novartis NX6236 with the Yieldgard event and Novartis N64Z4 with the Knockout event) were planted in duplicate 7.1-acre fields in 1998 and 1999. Thirty Angus x Charolais x Simmental cows in midgestation were allotted amongst two drylots or the eight crop residue fields to strip-graze for 126 days. Cow body condition scores were visually estimated biweekly and alfalfa-grass hay was supplemented to maintain a mean body condition score of 5 on a 9-point scale. Corn stalks and ear shanks from Pioneer 3489 corn had a higher (P\u3c.05) infestation of corn borers than did any of the bt-corn hybrids. Mean yields of harvested grain, dropped ears or grain, or crop residue dry matter (DM) or organic matter (OM) over the two years were not significantly affected by corn hybrid, but values for bt-corn hybrids were not equivalent to the non bt-corn hybrid. At grazing initiation, crop residues from Novartis NX6236 and N64Z4 had higher (P\u3c.05) concentrations of in vitro digestible organic matter (IVOMD) and lower (P\u3c.05) concentrations of acid detergent fiber (ADF) and acid detergent lignin (ADL) than Pioneer 3489 or Pioneer 34RO7. Rates of change in the concentrations of IVOMD, neutral detergent fiber (NDF), ADF, ADL and crude protein (CP) over winter were not significantly affected by corn hybrid, but rates for bt-corn hybrids were not equivalent to non bt-corn hybrids. Forage selected during feeding by fistulated steers did not differ in IVOMD concentrations between winter feeding systems or NDF, ADF, CP or acid detergent insoluble nitrogen (ADIN) concentrations between corn hybrids. Intakes of forage digestible DM, NDF and ADF did not differ between winter feeding systems, but were not equivalent to the non bt-corn hybrid. Mean amounts of hay required to maintain body condition score of cows maintained in a drylot were greater than cows grazing crop residues (3199 vs 825 lb DM/cow), but did not differ between corn hybrids

Altered Anesthetic Sensitivity of Mice Lacking Ndufs4, a Subunit of Mitochondrial Complex I

RDP and AQ were supported by the Howard Hughes Medical Institute (HHMI). AQ was a recipient of MICINN postdoctoral mobility program fellowship from the Spanish Ministerio de Ciencia e Innovación. PGM and MMS were supported by National Institutes of Health (NIH) grant GM58881. These studies were also supported in part by the Mitochondrial Research Guild. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Anesthetics are in routine use, yet the mechanisms underlying their function are incompletely understood. Studies in vitro demonstrate that both GABAA and NMDA receptors are modulated by anesthetics, but whole animal models have not supported the role of these receptors as sole effectors of general anesthesia. Findings in C. elegans and in children reveal that defects in mitochondrial complex I can cause hypersensitivity to volatile anesthetics. Here, we tested a knockout (KO) mouse with reduced complex I function due to inactivation of the Ndufs4 gene, which encodes one of the subunits of complex I. We tested these KO mice with two volatile and two non-volatile anesthetics. KO and wild-type (WT) mice were anesthetized with isoflurane, halothane, propofol or ketamine at post-natal (PN) days 23 to 27, and tested for loss of response to tail clamp (isoflurane and halothane) or loss of righting reflex (propofol and ketamine). KO mice were 2.5 - to 3- fold more sensitive to isoflurane and halothane than WT mice. KO mice were 2-fold more sensitive to propofol but resistant to ketamine. These changes in anesthetic sensitivity are the largest recorded in a mammal

IEX-1 directly interferes with RelA/p65 dependent transactivation and regulation of apoptosis

The early response gene IEX-1 plays a complex role in the regulation of apoptosis. Depending on the cellular context and the apoptotic stimulus, IEX-1 is capable to either enhance or suppress apoptosis. To further dissect the molecular mechanisms involved in the modulation of apoptosis by IEX-1, we analysed the molecular crosstalk between IEX-1 and the NF-kappa B pathway. Using GST-pulldown assays, a direct interaction of IEX-1 with the C-terminal region of the subunit RelA/p65 harbouring the transactivation domain of the NF-kappa B transcription factor was shown. This interaction negatively regulates RelA/p65 dependent transactivation as shown by GAL4-and luciferase assay and was confirmed for the endogenous proteins by co-immunoprecipitation experiments. Using deletion constructs, we were able to map the C-terminal region of IEX-1 as the critical determinant of the interaction with RelA/p65. We could further show, that IEX-1 mediated NF-kappa B inhibition accounts for the reduced expression of the anti-apoptotic NF-kappa B target genes Bc1-2, Bcl-xL, cIAP1 and cIAP2, thereby sensitizing cells for apoptotic stimuli. Finally, ChIP-assays revealed that IEX-1 associates with the promoter of these genes. Altogether, our findings suggest a critical role of IEX-1 in the NF-kappa B dependent regulation of apoptotic responses. (C) 2007 Elsevier B.V All rights reserved

FAPRI 2000 U.S. Agricultural Outlook

The Food and Agricultural Policy Research Institute (FAPRI), located at the University of Missouri and Iowa State University, develops long-term projections for world agriculture. The 10-year baseline results from a process that lasts several months. Initially, analysts from universities involved in the FAPRI consortium meet to determine the key assumptions that underlie the baseline. Based on these assumptions, preliminary projections are developed and then subjected to outside review. The last step is to incorporate comments from the reviewers, as well as any other changes, into the final baseline projections. Once the baseline is completed, FAPRI leaders travel to Washington, DC, for a series of briefings to congressional staff, analysts at the U.S. Department of Agriculture(USDA), and commodity groups

FAPRI 2000 World Agricultural Outlook

The Food and Agricultural Policy Research Institute (FAPRI) prepares a preliminary agricultural outlook on world agricultural production, consumption, and trade every fall. This is followed by an outside review, re-evaluation of projections, and completion of the final baseline in January. The FAPRI 2000 World Agricultural Outlook presents these final projections for world agricultural markets. A companion volume, the FAPRI 2000 U.S. Agricultural Outlook, presents the U.S. component of the baseline