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51.
Abstract: Since evidence is now available to support a nonendocrine autonomic function for thyrotropin-releasing hormone (TRH), quantitative measurements of TRH were made in nuclei of the vagal complex and other areas of the caudal medulla oblongata of the rat. Regions containing the dorsal motor nucleus of the vagus (DMN), nucleus tractus solitarius (NTS), hypoglossal nucleus, dorsal column nuclei, descending nucleus V (DNV), nucleus ambiguus (NA), raphe nuclei (MR) dorsomedial and ventromedial reticular formation, and inferior olivary nuclei were isolated from 300-μm-thick frozen sections of medulla by the micropunch technique. Each region was pooled bilaterally, homogenized in 0.1 M HCl, and vacuum-dried. Extracts were assayed for TRH by specific radioimmunoassay (RIA). TRH levels varied 100-fold among medulla nuclei. Highest content (ng/mg protein ± SEM) was found in DMN (14 ± 1.38) and NTS (4.7 ± 0.68), whereas lowest levels occurred in the DNV and MR (0.13, 0.06). Nearly 65% of the total medullary TRH was localized in nuclei associated with vagal complex (DMN, NTS, NA). Characterization of tissue immunoreactivity (TRHi) in these regions suggests the presence of TRH, since (1) medullary tissue extracts competed with 125I-TRH for antibody binding sites with the same affinity as authentic TRH; (2) TRHi in tissue extracts co-migrated with synthetic TRH when subjected to reverse-phase high performance liquid chromatography and Sephadex G-10 chromatography; and (3) rat serum TRH peptidases degraded TRHi and authentic TRH at similar rates. Another group of rats was subjected to unilateral (right side) vagotomy. At 33 weeks post-vagotomy, the vagal preganglionic cell population in the ipsilateral DMN was depleted 50–75%, while the contralateral side was unaffected. Interestingly, the content of TRH in the ipsilateral (right) DMN remained unchanged, whereas TRH in the contralateral DMN increased by 50%. In contrast, TRH was significantly elevated in the NA on the ipsilateral side of the lesion. TRH in both ipsi- and contralateral NTS was unchanged when compared with sham-operated controls. These results indicate that (1) TRH is present in several specific loci of the medulla; (2) very high levels are found in the vagal complex; and (3) vagotomy may alter TRH in the contralateral DMN and ipsilateral NA. 相似文献
52.
Analysis of field established xenogeneic interactions among five Porites species from Sesoko Island, Okinawa, revealed a transitive type of hierarchy as: P. rus > P. cylindrica > P. lobata > P. australiensis> P. lutea. Out of the 111 interspecific encounters studied, in only 5.4% reciprocal interactions were recorded, and in a single case, the opposite directionality of hierarchy was documented. Allogeneic encounters were also observed. A single major effector mechanism, an overgrowth (together with secondary outcomes such as the formation of small points of rejection, bleaching and pink color formation along a narrow peripheral belt of contacting tissues), was the only response in all 10 xenogeneic and 5 allogeneic combinations. In some massive colonies, a long contacting line of up to 50 cm was established. No sign for allelopathy, stand-off or rejection from a distance (i.e., by sweeper tentacles, sweeper polyps) was observed. Results are discussed with the accumulated data on Porites species from different reefs, worldwide, confirming that this genus is commonly lower in the hierarchy of xenogeneic interactions. 相似文献
53.
The Chemscore function was implemented as a scoring function for the protein-ligand docking program GOLD, and its performance compared to the original Goldscore function and two consensus docking protocols, "Goldscore-CS" and "Chemscore-GS," in terms of docking accuracy, prediction of binding affinities, and speed. In the "Goldscore-CS" protocol, dockings produced with the Goldscore function are scored and ranked with the Chemscore function; in the "Chemscore-GS" protocol, dockings produced with the Chemscore function are scored and ranked with the Goldscore function. Comparisons were made for a "clean" set of 224 protein-ligand complexes, and for two subsets of this set, one for which the ligands are "drug-like," the other for which they are "fragment-like." For "drug-like" and "fragment-like" ligands, the docking accuracies obtained with Chemscore and Goldscore functions are similar. For larger ligands, Goldscore gives superior results. Docking with the Chemscore function is up to three times faster than docking with the Goldscore function. Both combined docking protocols give significant improvements in docking accuracy over the use of the Goldscore or Chemscore function alone. "Goldscore-CS" gives success rates of up to 81% (top-ranked GOLD solution within 2.0 A of the experimental binding mode) for the "clean list," but at the cost of long search times. For most virtual screening applications, "Chemscore-GS" seems optimal; search settings that give docking speeds of around 0.25-1.3 min/compound have success rates of about 78% for "drug-like" compounds and 85% for "fragment-like" compounds. In terms of producing binding energy estimates, the Goldscore function appears to perform better than the Chemscore function and the two consensus protocols, particularly for faster search settings. Even at docking speeds of around 1-2 min/compound, the Goldscore function predicts binding energies with a standard deviation of approximately 10.5 kJ/mol. 相似文献
54.
55.
William A. Alexander 《Molecular simulation》2015,41(8):610-612
In a recent study of the Ar–CF4 intermolecular interaction potential [Shen C-C, Chang R-Y. Accurate ab initio calculation of the Ar–CF4 intermolecular potential energy surface. Mol Sim. 2010;36:1111–1122], Shen and Chang (SC) illustrated how the use of bond functions can improve the accuracy and basis-set saturation of electronic structure calculations employing perturbation and coupled-cluster theory. SC then used these ab initio data to derive analytic potential energy functions for use in chemical dynamics simulations. We critically examine these analytic potentials and comment on their usage in such simulations. Our analysis highlights the need for care and global validation when deriving analytic potential energy functions. 相似文献
56.
Sex assessment is key when investigating human remains either from medicolegal contexts or archaeological sites. Sex is usually assessed by examination of the skull and pelvis, but this may not always be possible if skeletal material is fragmented or incomplete. The present study investigated the potential for using carpals to assess sex, utilizing 100 individuals of known-sex from the Christ Church, Spitalfields Collection, curated at the Natural History Museum (London). A series of newly-defined measurements are applied to all eight carpals. Inter and intraobserver error tests show that all measurements are satisfactorily reproduced by the first author and another observer. Paired t-tests to investigate side asymmetry of the carpals reveal that some, but not all, measurements are consistently larger on the right hand side than the left. Independent t-tests confirm that all carpals are sexually dimorphic. Univariate measurements produce accuracy levels that range from 64.6 to 84.7%. Stepwise discriminant function analysis, devised separately for left and right sides, provides reliable methods for assessing sex from single and multiple carpals, with an accuracy range of 71.7 to 88.6%. All functions derived are tested for accuracy on a sample of 20 additional individuals from the Christ Church, Spitalfields Collection. 相似文献
57.
58.
Artis D 《International journal for parasitology》2006,36(6):723-733
Parasitic nematode infections of humans and livestock continue to impose a significant public health and economic burden worldwide. Murine models of intestinal nematode infection have proved to be relevant and tractable systems to define the cellular and molecular basis of how the host immune system regulates resistance and susceptibility to infection. While susceptibility to chronic infection is propagated by T helper cell type 1 cytokine responses (characterised by production of IL-12, IL-18 and interferon-gamma), immunity to intestinal-dwelling adult nematode worms is critically dependent on a type 2 cytokine response (controlled by CD4+T helper type 2 cells that secrete the cytokines IL-4, IL-5, IL-9 and IL-13). However, the immune effector mechanisms elicited by type 2 cytokines in the gut microenvironment that precipitate worm expulsion have remained elusive. This review focuses on new studies that implicate host intestinal epithelial cells as one of the dominant immune effector cells against this group of pathogens. Specifically, three recently identified type 2 cytokine-dependent pathways that could offer insights into the mechanisms of expulsion of parasitic nematodes will be discussed: (i) the intelectins, a new family of galactose-binding lectins implicated in innate immunity, (ii) the resistin-like molecules, a family of small cysteine-rich proteins expressed by multiple cell types, and (iii) cytokine regulation of intestinal epithelial cell turnover. Identifying how the mammalian immune response fights gastrointestinal nematode infections is providing new insights into host protective immunity. Harnessing these discoveries, coupled with identifying what the targets of these responses are within parasitic nematodes, offers promise in the design of a new generation of anti-parasitic drugs and vaccines. 相似文献
59.
《Bioscience, biotechnology, and biochemistry》2013,77(5):886-890
3′-O-Caffeylerigeroside (pyromeconic acid 3-O-β-D-glucoside 3′-O-caffeyl ester) was obtained from the leaves of Erigeron annuus as a new pyromeconic acid derivative, and its structure was elucidated. Together with the γ-pyrone derivative, pyromeconic acid (3-hydroxy-4H-pyran-4-one) and its β-glucoside (erigeroside) were also isolated from the aerial parts of E. annuus. The siderophile activity of pyromeconic acid was also studied. 相似文献
60.
Jianbin Chen Xi Zhang Tiansu Wang Zhendong Li Guijun Guan Yunhan Hong 《DNA research》2012,19(5):423-433
Gene targeting (GT) can introduce subtle alterations into a particular locus and represents a powerful tool for genome editing. Engineered zinc finger nucleases (ZFNs) are effective for generating minor allelic alterations. Efficient detection of such minor alterations remains one of the challenges in ZFN-mediated GT experiments. Here, we report the establishment of procedures allowing for efficient detection, quantification and enrichment of such subtle alterations. In a biallelic model, polyacrylamide gel electrophoresis (PAGE) is capable of detecting rare allelic variations in the form of DNA heteroduplexes at a high efficiency of ∼0.4% compared with ∼6.3% by the traditional T7 endonuclease I-digestion and agarose gel electrophoresis. In a multiple allelic model, PAGE could discriminate different alleles bearing addition or deletion of 1–18 bp as distinct bands that were easily quantifiable by densitometry. Furthermore, PAGE enables enrichment for rare alleles. We show for the first time that direct endogenous GT is possible in medaka by ZFN RNA injection, whereas PAGE allows for detection and cloning of ZFN-targeted alleles in adults arising from ZFN-injected medaka embryos. Therefore, PAGE is effective for detection, quantification and enrichment of multiple fine allelic differences and thus offers a versatile tool for screening targeted subtle gene alterations. 相似文献