429,355 research outputs found
A sterospecific colorimetric assay for (s,s)-Adenosylmethionine quantification based on thiopurine methyltransferase-catalyzed thiol methylation
Get PDFS-Adenosyl-L-methionine (AdoMet or SAM) that is biologically synthesized by AdoMet synthetase bears an s-configuration at the sulfur atom. The chiral sulfonium spontaneously racemizes to form a mixture of s-and R-isomers of AdoMet under physiological conditions or normal storage conditions. The chirality of AdoMet greatly affects its activity; the R-isomer is not accepted as a substrate for AdoMet-dependent methyltransferases. We report a stereospecific colorimetric assay for (s,s)-adenosylmethionine quantification based on an enzyme-coupled reaction in which (s,s)-AdoMet reacts with 2-nitro-5-thiobenzoic acid (TNB) to form AdoHcy and 2-nitro-5-methylthiobenzoic acid. The transformation is catalyzed by recombinant human thiopurine S-methyltransferase (TPMT, EC 2.1.1.67), and is associated with a large spectral change at 410 nm. Accumulation of the S-adenosylhomocysteine (AdoHcy) product, a feedback inhibitor of TPMT, slows down the assay. AdoHcy nucleosidase (EC 3.2.2.9) irreversibly cleaves AdoHcy to adenine and s-ribosylhomocysteine, significantly shortening the assay time to less than 10 min. The assay is linear from 5 to at least 60 f.lM (s,s)AdoMet.Honors College, Washington State UniversityCannon, Lisa M. and Butler, Felice N. and Wan, Wei and zhou, Shaohui A sterospecific colorimetric assay for (s,s)-Adenosylmethionine quantification based on thiopurine methyltransferase-catalyzed thiol methylation, Washington State University Honors College thesis, Fall 2002, 23 p
Ocypus Zhou 2017, s. str.
No full textKey to species of the subgenus Ocypus s. str. from China (Improved based on Smetana, 2007) 1. Visible tergites 4 and 5 with yellow tomentose pubescence.....................................................2 - Visible tergites 4 and 5 without yellow tomentose pubescence................................................. 3 2. Dorsal surface of head covered with yellow tomentose pubescence.................. Ocypus (s. str.) weisei Harold, 1877 - Dorsal surface of head not covered with yellow tomentose pubescence........... Ocypus (s. str.) miwai (Bernhauer, 1943) 3. Apical portion of median lobe simple in ventral view, finger like, not gradually narrowed toward apex (Figs. 1-2 F, 2-2 F, 3-2 F)................................................................................................. 4 - Apical portion of median lobe not finger like in ventral view................................................... 6 4. Head narrow and elongate, only slightly wider than long (ratio1.20)................................................................5 5. Aedeagus shaped as in Figs. 3-1 B-C, 3-2 B-D; paramere reaching apex of median lobe................................................................................................... Ocypus (s. str.) pterosemanticus sp. nov. - Aedeagus shaped as in Figs. 2-1 B-C, 2-2 B-D; paramere not reaching apex of median lobe................................................................................................ Ocypus (s. str.) aglaosemanticus sp. nov. 6. Aedeagus with apical portion of median lobe relatively wide, and paramere gradually narrowed towards apex; apical portion of paramere not covering either side of apical portion of median lobe in ventral view (Smetana, 2011, Fig. 8)....................................................................................... Ocypus (s. str.) puetzi Smetana, 2011 - Apical portions of paramere dilated into lancet-shape, or covers left side of apical portion of median lobe................7 7. Legs uniformly rufobrunneous. Apical portion of both median lobe and paramere dilated into lancet-shape (Smetana, 2007, Fig. 3). Aedeagus as in Smetana, 2007, Figs. 3, 4............................... Ocypus (s. str.) umbro Smetana, 2007 - Legs predominantly dark. Apical portions of both median lobe and paramere not dilated into lancet-shape in ventral view...8 8. Sensory peg setae on underside of paramere moderately numerous, mostly situated on apical portion of paramere, only a few situated on lateral margins (Smetana, 2007, Fig. 13). Aedeagus as in Smetana, 2007, Figs. 11-13.............................................................................................. Ocypus (s. str.) zopyrus Smetana, 2007 - Underside of paramere with numerous sensory peg setae, extending along lateral margins of paramere...................9 9. Apical portion of paramere relatively narrow; groups of sensory peg setae on left and right margins rather close to each other (Smetana, 2007, Fig. 17); apical portion of median lobe long, narrow, with subacute apex (Smetana, 2007, Fig. 16). Aedeagus as in Smetana, 2007, Figs. 15-17.......................................... Ocypus (s. str.) thericles Smetana, 2007 - Apical portion of median lobe wide, with subacute apex (Fig. 4-2 F). Paramere relatively wide, with obtuse apex; groups of sensory peg setae on left and right margins distinctly separated from each other (Figs. 4-1 D, 4-2 G). Aedeagus as in Figs. 4-1 B, C, 4-2 B-D.......................................................... Ocypus (s. str.) rhoetus Smetana, 2007Published as part of Zhou, Hong-Zhang, 2017, Taxonomy of the subgenus Ocypus Leach (Coleoptera: Staphylinidae: Staphylinini) and three new species from China, pp. 293-310 in Zootaxa 4312 (2) on page 295, DOI: 10.11646/zootaxa.4312.2.5, http://zenodo.org/record/85286
Stenus (Hypostenus) yiae , Zhao & Zhou 2020, sp. nov.
No full text2. Stenus (Hypostenus) yiae Zhao & Zhou, sp. nov. Type Material. Holotype: male, CHINA, Beijing, Chaoyang, Datunxiang (116°24′E, 39°59′N), 21.V. 1996, Hong-zhang Zhou collected [Deposited in Institute of Zoology, Chinese Academy of Sciences (IZ-CAS)]; Paratypes: 1 female, same data as holotype; 1 male, 1 female, CHINA, Beijing (116°28′E, 40°13′N), 1942; 1 male, 2 females, CHINA, Fujian, Shaxian (117°46′E, 26°25′N), 15.VII.1977, Xiao-nan Luo collected; 2 males, 3 females, CHINA, Shanghai (121°29′E, 31°13′N), A. SAVIO collected; 14 ex., CHINA, Shanghai (121°29′E, 31°13′N), O. PIEL collected. [Deposited in Institute of Zoology, Chinese Academy of Sciences (IZ-CAS)] Diagnosis. This new species belongs to the cicindeloides group. It can be easily distinguished from S. (H.) verticalis Benick and S. (H.) primivenatus Zhao & Zhou sp. nov. by the absence of spots on elytra. It is similar to S. (H.) cicindeloides (Schaller), but differs from the latter by having a broad apical part of median lobe and a different spermatheca structure. Detailed description and illustrations of the species are provided by Zhao & Zhou (2008).Published as part of Zhao, Cai-Yun & Zhou, Hong-Zhang, 2020, Validation of Stenus (Hypostenus) primivenatus and Stenus (Hypostenus) yiae (Coleoptera, Staphylinidae, Steninae), pp. 591-592 in Zootaxa 4881 (3) on page 591, DOI: 10.11646/zootaxa.4881.3.11, http://zenodo.org/record/428387
Pseudo-spin-valve with L 10 (111)-oriented FePt fixed layer
No full textRecently we proposed a spin torque oscillator where the fixed layer has its magnetization easy-axis tilted with respect to the film plane to simultaneously achieve zero-field operation and high output power [Y. Zhou, C. L. Zha, S. Bonetti, J. Persson, and J. Åkerman, Appl. Phys. Lett. 92, 262508 (2008)]. Here we take the first step toward the realization of this device and fabricate successfully a pseudo-spin-valve using an L 10 (111)-oriented FePt fixed layer with tilted magnetocrystalline anisotropy. A total magnetoresistance (MR) of 0.86% is experimentally observed for the standard pseudo-spin-valve of the L 10 FePt/Cu/NiFe structure in applied fields up to 1.5 T. While part of the MR may originate from the FePt film alone, the dominating part of MR correlates with switching of the NiFe free layer. © 2009 American Institute of Physics.link_to_subscribed_fulltex
Stenus (Hypostenus) primivenatus Zhao & Zhou 2020, sp. nov.
No full text<i>1.</i> <i>Stenus (Hypostenus) primivenatus</i> Zhao & Zhou, sp. nov. <p> <b>Type Material.</b> <b>Holotype:</b> male, CHINA, Hainan, Jianfengling (180°52′E, 18°48′N), 20.VII. 2004, 650 m, Jie Wu and Yong-jie Chen collected. [Deposited in Institute of Zoology, Chinese Academy of Sciences (IZ-CAS)]</p> <p> <b>Diagnosis.</b> This new species belongs to the <i>cicindeloides</i> group. It can be easily distinguished from <i>S. (H.) cicindeloides</i> (Schaller) and <i>S. (H.) yiae</i> Zhao & Zhou <b>sp. nov.</b> by spots on elytra. It is similar to <i>S. (H.) verticalis</i> Benick, but can be distinguished from the narrow apical part of median lobe and small body. Although the median hooks of <i>S. (H.) primivenatus</i> Zhao & Zhou <b>sp. nov.</b> is not distinct sclerotized like other species of the <i>cicindeloides</i> group, the median hooks are still connected by slightly sclerotized part. Maybe this new species is primitive in this species group. Detailed description and illustrations of the species are provided by Zhao & Zhou (2008).</p>Published as part of <i>Zhao, Cai-Yun & Zhou, Hong-Zhang, 2020, Validation of Stenus (Hypostenus) primivenatus and Stenus (Hypostenus) yiae (Coleoptera, Staphylinidae, Steninae), pp. 591-592 in Zootaxa 4881 (3)</i> on page 591, DOI: 10.11646/zootaxa.4881.3.11, <a href="http://zenodo.org/record/4283876">http://zenodo.org/record/4283876</a>
Paederus Li & Zhou, 2009, s. str
No full textSubgenus Paederus s. str. Fabricius, 1775 Paederus Fabricius, 1775: 268 (as a genus); Scheerpeltz, 1957: 461 (as nominotypical subgenus); Coiffait, 1982: 32 (character, key); Frank, 1988: 141 (catalog); Smetana, 2004: 613 (catalog). Type species: Paederus riparius (Linnaeus, 1758) (by subsequent designation; Latreille, 1810: 427). Synonyms: Geopaederus Gistel, 1848: x (type species: Geopaederus riparius (Linnaeus, 1758), by original designation); Blackwelder, 1952: 169 (as objective synonym of Paederus s. str.). Neopaederus Blackwelder, 1939: 97 (type species: Paederus morio Mannerheim, 1830, by original designation); Blackwelder, 1952: 260 (as synonym of Paederus s. str.). Paederillus Casey, 1905: 62 (type species: Paederus littorarius Gravenhorst, 1806, by subsequent designation); Bernhauer & Schubert, 1912: 203 (as synonym of Paederus s. str.); Blackwelder, 1952: 285 Paederognathus Wendeler, 1928: 37 (type species: Paederus turrialbanus Wendeler, 1927; by original designation); Blackwelder, 1939: 120; 1952: 286 (as objective synonym of Paederus s. str.). Diagnosis. This subgenus can be easily distinguished from the other subgenera of Paederus by the brownish yellow mandibles and tibiae, antennae usually with basal three segments brownish yellow and the rest brown, elytra with parallel margins, about 1 / 5 longer than broad (Scheerpeltz 1957; Coiffait 1982; Boháč 1985). The aedeagus is broad and thick, the internal armature relatively complex, with teeth strongly sclerotized and slightly curved (Scheerpeltz 1957; Coiffait 1982). Compared to the subgenus Harpopaederus Scheerpeltz, 1957, in Paederus s.str. the dorsal plate of the median lobe is different: the median surface (rather than the edges) is depressed (in dorsal view), the apex of the plate is with a short and thin carina, whereas Harpopaederus lacks the depression and has the apex of the dorsal plate with a long carina. The same characters of the male genitalia can serve to separate Paederus s. str. from the subgenus Eopaederus Scheerpeltz, 1957.Published as part of Li, Xiao-Yan & Zhou, Hong-Zhang, 2009, A review of Chinese species of the subgenus Paederus s. str. (Coleoptera: Staphylinidae: Paederinae) with description of a new species, pp. 46-64 in Zootaxa 2083 on pages 47-48, DOI: 10.5281/zenodo.18737
Angiotensin II induces soluble fms-Like tyrosine kinase-1 release via calcineurin signaling pathway in pregnancy
Get PDFMaternal endothelial dysfunction in preeclampsia is associated with increased soluble fms-like tyrosine kinase-1 (sFlt-1), a circulating antagonist of vascular endothelial growth factor and placental growth factor. Angiotensin II (Ang II) is a potent vasoconstrictor that increases concomitant with sFlt-1 during pregnancy. Therefore, we speculated that Ang II may promote the expression of sFlt-1 in pregnancy. Here we report that infusion of Ang II significantly increases circulating levels of sFlt-1 in pregnant mice, thereby demonstrating that Ang II is a regulator of sFlt-1 secretion in vivo. Furthermore, Ang II stimulated sFlt-1 production in a dose- and time-dependent manner from human villous explants and cultured trophoblasts but not from endothelial cells, suggesting that trophoblasts are the primary source of sFlt-1 during pregnancy. As expected, Ang II-induced sFlt-1 secretion resulted in the inhibition of endothelial cell migration and in vitro tube formation. In vitro and in vivo studies with losartan, small interfering RNA specific for calcineurin and FK506 demonstrated that Ang II-mediated sFlt-1 release was via Ang II type 1 receptor activation and calcineurin signaling, respectively. These findings reveal a previously unrecognized regulatory role for Ang II on sFlt-1 expression in murine and human pregnancy and suggest that elevated sFlt-1 levels in preeclampsia may be caused by a dysregulation of the local renin/angiotensin system
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