371 research outputs found
Localization of the extracellular Ca<sup>2+</sup>/polyvalent cation-sensing protein in rat kidney
No full text We previously identified transcripts encoding a G protein-coupled, extracellular calcium/polyvalent cation-sensing receptor, RaKCaR, in rat kidney (D. Riccardi, J. Park, W.-S. Lee, G. Gamba, E. M. Brown, and S. C. Hebert. Proc. Natl. Acad. Sci. USA 92: 131–135, 1994), which was proposed to provide the mechanism for modulating a variety of renal functions in response to changes in extracellular Ca2+ (E. M. Brown. In: Handbook of Physiology. Bethesda, MD: Am. Physiol. Soc., 1992, sect. 8, vol. 2, chapt. 39, p. 1841–1916; and S. C. Hebert. Kidney Int. 50: 2129–2139, 1996). Here, we examine the cellular and regional distribution of receptor protein by immunofluorescence microscopy using a polyclonal antibody raised against a 22 amino acid region of the NH2 terminus of the receptor. The most intense fluorescence was seen at the basolateral border of cortical thick ascending limb cells. Basolateral staining for the receptor was also detected in medullary thick ascending limbs, in macula densa cells identified by costaining with antibody to brain nitric oxide synthase, NOS-B1, and in distal convoluted tubule cells distinguished by costaining for the apical thiazide-sensitive Na+-Cl−cotransporter. Apical anti-RaKCaR staining was detected at the base of the brush border of proximal tubules with decreasing intensity from S1 to S3 segments. In cortical collecting ducts, anti-RaKCaR staining was detected in some, but not all, type A intercalated cells identified by costaining with anti-H+-ATPase and anti-AE1 Cl−/[Formula: see text]exchanger antibodies. The present study demonstrates that RaKCaR protein is expressed in many different nephron segments and that the polarity of receptor expression varies with cell type along the nephron. These results suggest potential roles for the extracellular Ca2+/polyvalent cation-sensing receptor in responding to both circulating and urinary concentrations of divalent minerals and potentially other polyvalent cations (e.g., aminoglycoside antibiotics) to modulate nephron function. </jats:p
Holopedium atlanticum Rowe, Adamowicz & Hebert, 2007, n. sp.
No full text<i>Holopedium atlanticum</i> n. sp. <p> <b>Synonymy.</b> Individuals from North America previously identified as <i>H. amazonicum</i> should properly be identified as <i>H. atlanticum</i>.</p> <p>Birge (1918): 693, Fig. 1061b</p> <p>Pennak (1953): 364–365, Fig. 227d</p> <p>Brooks (1959): 603, Fig. 27.13</p> <p>Pennak (1978): 365–366, Fig. 254d</p> <p>Pennak (1989): 386–387, Fig. 12d</p> <p>Korovchinsky (1992): 77–78, Figs. 371–373, 375, 377</p> <p> <b>Etymology.</b> <i>atlanticum</i> refers to the distribution of this species in lakes along the eastern Atlantic seaboard of North America.</p> <p> <b>Type locality.</b> Moosehead Lake, Maine (45.633º N, 69.683º W). On Hwy ME-6, in close proximity to the town of Moosehead.</p> <p> <b>Type specimens. Holotype</b>: an ovigerous female in ethanol deposited in the CMN under accession number CMNC 2007-0741 (collection date September 2, 1993).</p> <p> <b>Paratypes</b>: 10 ovigerous females, preserved in ethanol, deposited in the CMN under accession number CMNC 2007-0742 (collection date September 2, 1993).</p> <p> <b>Material examined.</b> Other habitats with <i>H. atlanticum</i> are listed in Appendix A.</p> <p> <b>Morphological description.</b> FEMALE. Representative photomicrographs are shown in Fig. 10. The jelly coat is of the A type, in which the anterior jelly curl arches toward the anterior portion of the jelly coat, and the lateral lobes are undivided (see Montvilo <i>et al.</i> 1987).</p> <p>Adult carapace lengths range from 0.44–1.01 mm (mean 0.73 mm), while carapace heights range from 0.30–1.06 mm (mean 0.74 mm). The H/L ratios range from 0.68–1.37 (mean 1.00). The ventral carapace margin is ordinarily spinulated posteriorly, but smooth anteriorly. Individuals lacking spinulation along the entire ventral valve margin were encountered.</p> <p> Anal spine number ranges from 6–11 (mean 8.35). <i>Holopedium atlanticum</i> lacks a basal spine on each postabdominal claw. Each claw ordinarily has a row of denticles running laterally from the base of the claw to its midpoint, although individuals were observed that lacked claw denticulation.</p> <p> MALE. Males have been found in small numbers in collections from sites in North Carolina in May and June; however, they are typically found in the highest abundance in the autumn (Hegyi 1973). Males of this species were not examined in this study, and thus detailed morphometrics cannot be presented. However, Hegyi (1973) presented a photograph and brief description of a male <i>Holopedium</i> which, based on distributional data, is probably <i>H. atlanticum</i>.</p> <p> <b>Differential diagnosis.</b> Although <i>H. atlanticum</i> is morphologically indistinguishable from <i>H. amazonicum</i>, these two species have allopatric distributions reducing the likelihood of genetic exchange (Fig. 4 c,e). <i>Holopedium atlanticum</i> is distinguished from <i>H. acidophilum</i> by the larger size and greater number of anal spines of the latter species. It differs from members of the <i>H. gibberum</i> complex by the absence of a basal spine on either postabdominal claw. <i>Holopedium atlanticum</i> can be biochemically distinguished from <i>H. acidophilum</i> at the <i>Pgm</i> locus, as <i>H. atlanticum</i> produces an enzyme which migrates slower than that of the latter species. COI mtDNA sequence divergence between <i>H. atlanticum</i> and <i>H. amazonicum</i> averages 12.3%, while the divergence between <i>H. atlanticum</i> and <i>H. acidophilum</i> averages 10.6%. Based on current evidence, individuals showing less than 4.8% divergence from a representative COI mtDNA sequence (GenBank AF 245353) belong to <i>H. atlanticum</i>.</p> <p> <b>Distribution.</b> <i>H. atlanticum</i> was found along the Atlantic coast of North America from New Brunswick and Maine south to Florida, (Fig. 4 c). Populations of <i>Holopedium</i> reported by other workers from the southeastern United States are likely also <i>H. atlanticum</i>. Its range overlaps that of <i>H. glacialis</i> in the northeastern USA and southern New Brunswick, where these species occur sympatrically without hybridization. The extent of range overlap with <i>H. glacialis</i> is unresolved by this study, but several workers have identified <i>H. atlanticum</i> (formerly <i>H. amazonicum</i>) as far north as New Brunswick and <i>H. glacialis</i> (formerly <i>H. gibberum</i>) as far south as Tennessee and possibly South Carolina (Coker 1938, Bunting 1970, Hebert & Finston 1997).</p> <p> <b>Breeding system.</b> Males were not detected in populations collected throughout the summer in this study. In a life history study spanning two years, males were most abundant in early spring and late autumn (Hegyi 1973). In some southern localities, populations persist throughout the winter. Due to the existence of males, this species likely reproduces by cyclic parthenogenesis, but there is very little allozyme variation, suggesting that either this species engages in sexual reproduction infrequently or that variation has been trimmed due to a population bottleneck.</p> <p> A note regarding <i>H. groenlandicum</i> and <i>H. ramasarmii</i></p> <p> While individuals from Greenland were not included in the present study, the recently described species <i>H. groenlandicum</i> (Korovchinsky 2005) can purportedly be distinguished from <i>H. gibberum</i> by its “dorsally low shell and jelly envelope, shorter row of valve marginal spinules which are subdivided in groups, and comparatively longer postabdominal claws.” However, shell shape is a highly variable feature, which may be environmentally influenced (Røen 1962) and can depend upon the locality and presence/absence of fish (CLR pers. obs). The body lengths (0.74 to 1.09mm, mean 1.45mm), carapace heights (0.80 to 1.57mm, mean 1.19mm), and H:L ratios (0.641 to 1.000, mean 0.814) found by Korovchinsky (2005) in the Greenland populations fall within the ranges of values found in <i>H. gibberum</i> and <i>H. glacialis</i> populations in the present study (the preceding ranges and means that were not published in Korovchinsky [2005] were provided to CLR by that author). Jelly coat shape may be influenced by preservation (CLR, pers. obs), and therefore this trait may not be a good feature for diagnosing species. Moreover, the degree of carapace margin spinulation is also a highly variable trait within species (present study), although the discontinuous nature of the spinulation in the Greenland populations is noteworthy. Finally, the length of the postabdominal claws reported by Korovchinsky (2005, his Figure 1) is within the range of claw lengths observed for the <i>H. gibberum</i> s.s. populations studied here. Furthermore, the fact that we detected closely related lineages of <i>H. gibberum</i> s.s. in both northern Europe and North America suggests that similar lineages may be found in intervening arctic areas.</p> <p> Individuals from India were also not included in the present study. Consideration of the differences between either of the species in the <i>H. gibberum</i> complex and <i>H. ramasarmii</i> (Rao <i>et al.</i> 1998) is not currently possible due to the poor description of the latter species, lacking in detail. Korovchinsky (2004) labeled this species <i>incertae sedis</i>.</p> <p> We suggest that genetic evidence is required to determine if <i>H. groenlandicum</i> and <i>H. ramasarmii</i> are distinct species or if they are synonymous with described taxa.</p>Published as part of <i>Rowe, Chad L., Adamowicz, Sarah J. & Hebert, Paul D. N., 2007, Three new cryptic species of the freshwater zooplankton genus Holopedium (Crustacea: Branchiopoda: Ctenopoda), revealed by genetic methods, pp. 1-49 in Zootaxa 1656</i> on pages 34-36, DOI: <a href="http://zenodo.org/record/179852">10.5281/zenodo.179852</a>
Calcium and salinity sensing by the thick ascending limb: A journey from mammals to fish and back again
No full textCalcium and salinity sensing by the thick ascending limb: A journey from mammals to fish and back again. The roles of the CaSR in endocrine, epithelial, CNS, and other cells have been reviewed previously17-20,27-33. This brief review focuses on the roles of the CaSR in the thick ascending limb of Henle (TAL), and is written in honor of my mentor and long-term friend and colleague, Thomas E. Andreoli, on the occasion of his retirement. My early studies of TAL function with Tom Andreoli were the inspiration for this work
Australian Sphingidae – DNA Barcodes Challenge Current Species Boundaries and Distributions
No full text© 2014 Rougerie et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article.NHM Repositor
A data mining formalization to improve hypergraph transversal computation
No full text@article{RI-HEBERT-2007, author = {Hébert, C. and Bretto, A. and Crémilleux, B.}, title = {A data mining formalization to improve hypergraph transversal computation}, journal = {Fundamenta Informaticae}, year = {2007}, volume = {80}, number = {4}, pages = {415-433}, note = {IOS Press} }International audienc
Partially active channels produced by PKA site mutation of the cloned renal K<sup>+</sup> channel, ROMK2 (kir1.2)
No full text The activity of the cloned renal K+ channel (ROMK2) is dependent on a balance between phosphorylation and dephosphorylation. There are only three protein kinase A (PKA) sites on ROMK2, with the phosphorylated residues being serine-25 (S25), serine-200 (S200), and serine-294 (S294) (Z.-C. Xu, Y. Yang, and S. C. Hebert. J. Biol. Chem. 271: 9313–9319, 1996). We previously mutated these sites from serine to alanine to study the contribution of each site to overall channel function. Here we have studied each of these single PKA site mutants using the single-channel configuration of the patch-clamp technique. Both COOH-terminal mutations at sites S200A and S294A showed a decreased open channel probability ( P o), whereas the NH2-terminal mutation at site S25A showed no change in P o compared with wild-type ROMK2. The decrease in P o for the S200A and S294A mutants was caused by the additional presence of a long closed state. In contrast, the occurrence of the S25A channel was ∼66% less, suggesting fewer active channels at the membrane. The S200A and S294A channels had different kinetics compared with wild-type ROMK2 channels, showing an increased occurrence of sublevels. Similar kinetics were observed when wild-type ROMK2 was excised and exposed to dephosphorylating conditions, indicating that these effects are specifically a property of the partially phosphorylated channel and not due to an unrelated effect of the mutation. </jats:p
Mission: Vol. 10, No. 1
No full textMission: Vol. 10, No. 1. The articles in this issue include: Christian Faith and Politics by Gerald C. Tiffin, The Faith to Die--Again by Dianne Shewmaker, Those Anti- Non-Sunday School Churches by Larry Branum, Mary and Martha a poem by Brin Renr, The Church and the Rhodesian Crisis by Chester Woodhall, Ode to Phillip Roseberry a poem by Keith Wagner, Confronting the Vacuum of Meaning a sermon by David Reagan, Tradition, Responsibility, and the Restoration Principle by Steven Spidell, Books reviews by Hebert A. Marlow, Jr., Looking Out, and Cross Currents
Impact: Collected Essays on the Threat of Economic Inequality
No full textOn April 17, 2015, the Impact Center for Public Interest Law at New York Law School hosted a symposium entitled Tackling Economic Inequality to bring together policymakers, advocates, academics, and community members to explore some of the causes and solutions to this growing problem. The essays collected in this volume, written by leading social justice advocates, are published to stimulate continued conversation on this critically important issue.
Contributors:
THE CHALLENGE OF ECONOMIC INEQUALITY | Richard R. Buery, Jr., Honorable Fern Fisher
HOUSING AND COMMUNITY | Steven W. Bender, Elise C. Boddie , Andrew Scherer
CRIMINAL JUSTI CE REFORM | Michael Pinard, SpearIt, Erika L. Wood, Reginald T. Shuford, Ronald F. Day
POLITICAL PARTICIPATION | J. Gerald Hebert
REPRODU CTIVE RIGHTS AND WOMEN’S EQUALITY | Janet Crepps , Kelly Baden
PROTECTING FAMILIES | Kele M. Stewart
LESSONS FROM NEW YOR K CITY | Ellen Yaroshefsky, Anna Shwedel, Melanie Hartzog, Patti Banghart, Jennifer Jones Austin, Steven Bank
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