A study of mitochondrial membranes in relation to elementary particles

Elementary particles that commonly have been seen by electron microscopy to be attached by stalks to mitochondrial cristae in negatively stained preparations, were not apparent in similarly stained mitochondria from exponentially growing wild-type Neurospora crassa when these were isolated in sucrose solution containing 1 x 10^-3 M EDTA. However, elementary particles were easily demonstrable in electron micrographs if the mitochondria were isolated without EDTA in the sucrose solution. A biochemical study indicated that both kinds of mitochondrial preparations, isolated in the presence or absence of EDTA, had about the same capacity for oxidative phosphorylation. Observations on rat-liver mitochondria also suggested that the stalked elementary particles were more easily demonstrated if the preparation was made in the absence of EDTA. It was difficult to demonstrate elementary particles in wild-type Neurospora mitochondria isolated with or without EDTA and subsequently prepared for electron microscopy by spreading on the surface of an aqueous solution of potassium phosphotungstate. Elementary particles could be demonstrated in poky Neurospora mitochondria isolated with EDTA if the mitochondria were spread on the surface of an aqueous solution of phosphotungstate. It was concluded that biochemical functions associated with elementary particles are independent of structural configuration as seen by electron microscopy

The Revenues-Expenditures Nexus: Evidence from Local Government Data

This paper examines the intertemporal linkages between local government expenditures and revenues. In the terminology that has become standard in the literature on vector autoregression analysis, the issue is whether revenues Granger-cause expenditures, or expenditures Granger-cause revenues. The main results that emerge from an analysis of fiscal data from 171 municipal governments over the period 1972-1980 are that: 1) one or two years are sufficient to summarize the relevant dynamic interrelationships; 2) there are important intertemporal linkages between expenditures, taxes and grants; and 3) past revenues help predict current expenditures, but past expenditures do not alter the future path of revenues. This last finding is contrary to results that have emerged from previous analyses of federal fiscal data, and hence suggests the need for additional research on the differences in the processes generating local and federal decisions.

Reducing poverty and inequity in Latin America

French version available in IDRC Digital Library: Atténuer la pauvreté et l'iniquité en Amérique latineSpanish version available in IDRC Digital Library: Reducción de la pobreza y desigualdad en América Latin

Atténuer la pauvreté et l'iniquité en Amérique latine

Version anglaise disponible dans la Bibliothèque numérique du CRDI: Reducing poverty and inequity in Latin AmericaVersion espagnole disponible dans la Bibliothèque numérique du CRDI: Reducción de la pobreza y desigualdad en América Latin

Reducción de la pobreza y desigualdad en América Latina

Versión en inglés disponible en la Biblioteca Digital del IDRC: Reducing poverty and inequity in Latin AmericaVersión en francés disponible en la Biblioteca Digital del IDRC: Atténuer la pauvreté et l'iniquité en Amérique latin

Discordant localization of WFA reactivity and brevican/ADAMTS-derived fragment in rodent brain

<p>Abstract</p> <p>Background</p> <p>Proteoglycan (PG) in the extracellular matrix (ECM) of the central nervous system (CNS) may act as a barrier for neurite elongation in a growth tract, and regulate other characteristics collectively defined as structural neural plasticity. Proteolytic cleavage of PGs appears to alter the environment to one favoring plasticity and growth. Brevican belongs to the lectican family of aggregating, chondroitin sulfate (CS)-bearing PGs, and it modulates neurite outgrowth and synaptogenesis. Several ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs) are glutamyl-endopeptidases that proteolytically cleave brevican. The purpose of this study was to localize regions of adult CNS that contain a proteolytic-derived fragment of brevican which bears the ADAMTS-cleaved neoepitope sequence. These regions were compared to areas of <it>Wisteria floribunda </it>agglutin (WFA) reactivity, a common reagent used to detect "perineuronal nets" (PNNs) of intact matrix and a marker which is thought to label regions of relative neural stability.</p> <p>Results</p> <p>WFA reactivity was found primarily as PNNs, whereas brevican and the ADAMTS-cleaved fragment of brevican were more broadly distributed in neuropil, and in particular regions localized to PNNs. One example is hippocampus where the ADAMTS-cleaved brevican fragment is found surrounding pyramidal neurons, in neuropil of stratum oriens/radiatum and the lacunosum moleculare. The fragment was less abundant in the molecular layer of the dentate gyrus. Mostly PNNs of scattered interneurons along the pyramidal layer were identified by WFA. In lateral thalamus, the reticular thalamic nucleus stained abundantly with WFA whereas ventral posterior nuclei were markedly immunopositive for ADAMTS-cleaved brevican. Using Western blotting techniques, no common species were reactive for brevican and WFA.</p> <p>Conclusion</p> <p>In general, a marked discordance was observed in the regional localization between WFA and brevican or the ADAMTS-derived N-terminal fragment of brevican. Functionally, this difference may correspond to regions with varied prevalence for neural stability/plasticity.</p

SKS Splitting Beneath Mount St. Helens: Constraints on Subslab Mantle Entrainment

Observations of seismic anisotropy can provide direct constraints on the character of mantleflow in subduction zones, critical for our broader understanding of subduction dynamics. Here wepresent over 750 new SKS splitting measurements in the vicinity of Mount St. Helens in the Cascadiasubduction zone using a combination of stations from the iMUSH broadband array and Cascades VolcanoObservatory network. This provides the highest density of splitting measurements yet available inCascadia, acting as a focused“telescope”for seismic anisotropy in the subduction zone. We retrieve spatiallyconsistent splitting parameters (mean fast directionΦ: 74°, mean delay time∂t: 1.0 s) with the azimuthaloccurrence of nulls in agreement with the fast direction of splitting. When averaged across the array, a90° periodicity in splitting parameters as a function of back azimuth is revealed, which has not beenrecovered previously with single‐station observations. The periodicity is characterized by a sawtooth patterninΦwith a clearly defined 45° trend. We present new equations that reproduce this behavior based uponknown systematic errors when calculating shear wave splitting from data with realistic seismic noise.The corrected results suggest a single layer of anisotropy with an ENE‐WSW fast axis parallel to the motionof the subducting Juan de Fuca plate; in agreement with predictions for entrained subslab mantleflow. Thesplitting pattern is consistent with that seen throughout Cascadia, suggesting that entrainment of theunderlying asthenosphere with the subducting slab is coherent and widespread.The broadband seismic component of the iMUSH project was supported by National Science Foundation grants EAR‐1144568, EAR‐1144351, EAR‐1460291, and EAR‐1444275. CME acknowledges support from the Australian Research Council (DE190100062). We thank the 2017 IRIS undergraduate summer intern program for providing support to A. W. to work with E. A. W. at the University of Washington. The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to waveforms, related metadata, and/or derived products used in this study. IRIS Data Services are funded through the Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the National Science Foundation under Cooperative Agreement EAR‐1261681

Application of Paleoclimatology to Coral Reef Monitoring and Management

The skeletons of reef-building corals are valuable archives of climatic and environmental information. Paleoclimatic data chiefly have been generated in areas most sensitive to global or regional climatic variability. However, these records also provide valuable information on anthropogenic influences – guidance of value to resource managers. NOAA’s Coral Reef Watch targets observations of current and past coral reef health in or near marine protected areas through satellites, in situ sensor platforms, and paleoclimatic analyses. Paleoclimatic data provide retrospective monitoring through multi-century environmental reconstructions that improve our understanding of past stress to coral reefs. Two sites in the Florida Keys National Marine Sanctuary were the first to benefit from Coral Reef Watch Program paleoenvironmental analyses. Coral cores yielded direct measurements of δ18O, δ13C, Sr/Ca, and coral skeletal growth (extension, density, and calcification) and reconstructions of reef temperatures. Temperature reconstructions were compared with instrumental data from nearby stations and global data sets, while skeletal growth was used to infer responses to changing climatic and environmental conditions. Differences between paleoclimatic data and gridded datasets demonstrated that paleodata provide more accurate estimates of reef temperatures as they sample subsurface temperatures where the corals live. Because of relatively high thermal variability, at least 12 samples per year are needed at these sites. Further work will extend these records back in time, to new locations, and expand on the data reconstructed from the skeletal archives

Efficacy of N-acetyl cysteine in traumatic brain injury

In this study, using two different injury models in two different species, we found that early post-injury treatment with NAcetyl Cysteine (NAC) reversed the behavioral deficits associated with the TBI. These data suggest generalization of a protocol similar to our recent clinical trial with NAC in blast-induced mTBI in a battlefield setting [1], to mild concussion from blunt trauma. This study used both weight drop in mice and fluid percussion injury in rats. These were chosen to simulate either mild or moderate traumatic brain injury (TBI). For mice, we used novel object recognition and the Y maze. For rats, we used the Morris water maze. NAC was administered beginning 30-60 minutes after injury. Behavioral deficits due to injury in both species were significantly reversed by NAC treatment. We thus conclude NAC produces significant behavioral recovery after injury. Future preclinical studies are needed to define the mechanism of action, perhaps leading to more effective therapies in man