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1.
Physical and biochemical aspects of a proposed search for extraterrestrial eukaryotes (SETE) are considered. Such a program should approach the distinction between a primitive eukaryote and an archaebacteria. The emphasis on gene silencing suggests a possible assay suitable for a robotic investigation of eukaryoticity, so as to be able to decide whether the first steps towards eukaryogenesis have been taken in an extraterrestrial planet, or satellite. The experiment would consist of searching for cellular division and the systematic related delay in replication of heterochromatic chromosome segments. It should be noticed that the direct search for a membrane-bounded set of chromosomes does not necessarily determine eukaryotic identity, as there are prokaryotes that have membrane-bounded nucleoids. A closer look at the protein fraction of chromatin (mainly histones) does not help either, as there are some eukaryotes that may lack histones; there are also some bacteria as well as archaebacteria with histone-like proteins in their nucleoids. Comments on the recent suggestion of possible environments for a SETE program are discussed: the deep crust of Mars, and the Jovian satellite Europa, provided the existence of an ocean under its ice-covered surface is confirmed by the current Galileo mission. 相似文献
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Michihiro Ohta Priyanka Jood Masayuki Murata Chul‐Ho Lee Atsushi Yamamoto Haruhiko Obara 《Liver Transplantation》2019,9(23)
This review discusses the longstanding efforts to develop advanced thermoelectrics through a multidisciplinary approach by combining condensed matter physics, nanotechnology, solid‐state chemistry, electrical engineering, mechanical engineering, and metrology. The phonon dynamics of skutterudites, clathrates, tetrahedrites, and layered LaOBiSSe are investigated through inelastic neutron scattering, allowing insights into their low lattice thermal conductivity due to rattling in a cage as well as under planar coordination. The electrical resistivity, Seebeck coefficient, and Hall coefficient of Bi‐nanowires are successfully measured with a home‐made system, demonstrating a size effect in thermoelectric and galvanomagnetic phenomena. For PbTe‐based bulk thermoelectrics, an exceptionally high figure of merit ZT (≈1.8 at 800 K) is achieved through nanostructuring. Moreover, correspondingly high conversion efficiency (≈11% for a temperature difference of 590 K) is demonstrated in nanostructured PbTe‐based modules. Sulfides (tetrahedrite, colusite, and CdI2‐type layered systems) and arsenides (LnFeAsO and BaZn2As2) are developed as environmentally friendly and emerging thermoelectric materials, respectively. The output power and efficiency of modules with novel materials, including nanostructured PbTe, Zn4Sb3, and clathrates, are measured with the highly accurate self‐made system. Future opportunities and challenges for the widespread use of thermoelectric waste heat recovery and energy harvesting are also discussed. 相似文献
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Panina I. S. Chugunov A. O. Efremov R. G. 《Russian Journal of Bioorganic Chemistry》2018,44(6):653-664
Russian Journal of Bioorganic Chemistry - The growing problem of antibiotic resistance in medicine is focusing attention on antimicrobial compounds targeting non-protein molecules, which have more... 相似文献
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A new dual ester-urethane melt condensation methodology for biological monomers-amino acids was developed to synthesize new classes of thermoplastic polymers under eco-friendly and solvent-free polymerization approach. Naturally abundant l-amino acids were converted into dual functional ester-urethane monomers by tailor-made synthetic approach. Direct polycondensation of these amino acid monomers with commercial diols under melt condition produced high molecular weight poly(ester-urethane)s. The occurrence of the dual ester-urethane process and the structure of the new poly(ester-urethane)s were confirmed by (1)H and (13)C NMR. The new dual ester-urethane condensation approach was demonstrated for variety of amino acids: glycine, β-alanine, l-alanine, l-leucine, l-valine, and l-phenylalanine. MALDI-TOF-MS end group analysis confirmed that the amino acid monomers were thermally stable under the melt polymerization condition. The mechanism of melt process and the kinetics of the polycondensation were studied by model reactions and it was found that the amino acid monomer was very special in the sense that their ester and urethane functionality could be selectively reacted by polymerization temperature or catalyst. The new polymers were self-organized as β-sheet in aqueous or organic solvents and their thermal properties such as glass transition temperature and crystallinity could be readily varied using different l-amino acid monomers or diols in the feed. Thus, the current investigation opens up new platform of research activates for making thermally stable and renewable engineering thermoplastics from natural resource amino acids. 相似文献
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Phagotrophic euglenids are one of the most diverse and important forms of heterotrophic flagellates in sediment systems, and are key to understanding the evolution of photosynthetic euglenids and ‘primary osmotrophs’, yet relatively little is known about their biodiversity and phylogenetic relationships. A wealth of light microscopy‐based information is available, but little progress has been made in associating this with molecular sequence data. We established a protocol to obtain light microscopy data and molecular data from single euglenid cells isolated from environmental samples. Individual cells from freshwater and marine benthic samples were isolated and rinsed by micropipetting, documented using high‐resolution photomicroscopy, then subjected to single‐cell nested PCR using taxon‐specific primers in combination with universal eukaryotic primers, generating > 75% or full‐length SSU rDNA sequences. As a proof‐of‐principle eight individuals were characterised and subjected to phylogenetic analyses. Many of these cells were identified as Anisonema or Dinema, and grouped with existing sequences assigned to these taxa, and with a ‘Peranema sp.’ sequence that we could now clearly demonstrate was misidentified or misannotated. Another cell is Heteronema c.f. exaratum, the first ‘skidding heteronemid’ for which sequence data are available. This is not closely related to Heteronema scaphurum, and intriguingly, branches as the sister group to primary osmotrophs. A cell similar to Ploeotia vitrea (the type of this genus), shows no particular phylogenetic affinity to Ploeotia costata, the best studied Ploeotia species. Our experimental protocol provides a useful starting point for future analyses on euglenid biodiversity (including environmental sequence surveys), and their evolution and systematics. 相似文献
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《Endocrine practice》2014,20(5):461-462
Objective: BRAF mutations are the most common genetic alteration found in papillary thyroid carcinoma (PTC). Approximately, 90% correspond to BRAFV600E, although other less common BRAF mutations have been described. The aim of this study was to describe a new mutation on BRAF gene discovered on the previous thyroid cytology of a patient diagnosed with a follicular variant of PTC (FV-PTC).Methods: The mutation was identified by independent cloning of the 2 alleles and direct sequencing in the 相似文献
Pheochromocytoma and Tetralogy of Fallot: a Rare But Potentially Dangerous Combination
Rajeev Kasaliwal; Vijaya Sarathi; Reshma Pandit; Sweta R. Budyal; Amol Bukan; Harshal Kakade; Varsha S. Jagtap; Anurag R. Lila; Tushar Bandgar; Padmavathy S. Menon; Nalini S. ShahHypercalcemia and Acromegaly – Clarifying the connections: A Case Report and Review of the Literature
Pooja Manroa; Subramanian Kannan; Betul Hatipoglu; Angelo LicataA Case of “Late-Onset” Idiopathic Infantile Hypercalcemia Secondary to Mutations in the Cyp24a1 Gene
Peter Wolf; Thomas Müller-Sacherer; Sabina Baumgartner-Parzer; Yvonne Winhofer; Judit Kroo; Alois Gessl, Anton Luger; Michael Krebs8.
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Cellular metabolism is a very complex process. The biochemical pathways are fundamental structures of biology. These pathways possess a number of regeneration steps which facilitate energy shuttling on a massive scale. This facilitates the biochemical pathways to sustain the energy currency of the cells. This concept has been mimicked using electronic circuit components and it has been used to increase the efficiency of bio-energy generation. Six of the carbohydrate biochemical pathways have been chosen in which glycolysis is the principle pathway. All the six pathways are interrelated and coordinated in a complex manner. Mimic circuits have been designed for all the six biochemical pathways. The components of the metabolic pathways such as enzymes, cofactors etc., are substituted by appropriate electronic circuit components. Enzymes are related to the gain of transistors by the bond dissociation energies of enzyme-substrate molecules under consideration. Cofactors and coenzymes are represented by switches and capacitors respectively. Resistors are used for proper orientation of the circuits. The energy obtained from the current methods employed for the decomposition of organic matter is used to trigger the mimic circuits. A similar energy shuttle is observed in the mimic circuits and the percentage rise for each cycle of circuit functioning is found to be 78.90. The theoretical calculations have been made using a sample of domestic waste weighing 1.182 kg. The calculations arrived at finally speak of the efficiency of the novel methodology employed. 相似文献
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Christoph Jindra Bettina Huber Saeed Shafti-Keramat Markus Wolschek Boris Ferko Thomas Muster Sabine Brandt Reinhard Kirnbauer 《PloS one》2015,10(9)
Persistent infection with high-risk human papillomavirus (HPV) types, most often HPV16 and HPV18, causes all cervical and most anal cancers, and a subset of vulvar, vaginal, penile and oropharyngeal carcinomas. Two prophylactic virus-like particle (VLPs)-based vaccines, are available that protect against vaccine type-associated persistent infection and associated disease, yet have no therapeutic effect on existing lesions or infections. We have generated recombinant live-attenuated influenza A viruses expressing the HPV16 oncogenes E6 and E7 as experimental immunotherapeutic vaccine candidates. The influenza A virus life cycle lacks DNA intermediates as important safety feature. Different serotypes were generated to ensure efficient prime and boost immunizations. The immune response to vaccination in C57BL/6 mice was characterized by peptide ELISA and IFN-γ ELISpot, demonstrating induction of cell-mediated immunity to HPV16 E6 and E7 oncoproteins. Prophylactic and therapeutic vaccine efficacy was analyzed in the murine HPV16-positive TC-1 tumor challenge model. Subcutaneous (s.c.) prime and boost vaccinations of mice with recombinant influenza A serotypes H1N1 and H3N2, followed by challenge with TC-1 cells resulted in complete protection or significantly reduced tumor growth as compared to control animals. In a therapeutic setting, s.c. vaccination of mice with established TC-1 tumors decelerated tumor growth and significantly prolonged survival. Importantly, intralesional vaccine administration induced complete tumor regression in 25% of animals, and significantly reduced tumor growth in 50% of mice. These results suggest recombinant E6E7 influenza viruses as a promising new approach for the development of a therapeutic vaccine against HPV-induced disease. 相似文献
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Orexin A (OXA) is an excitatory hypothalamic neurotransmitter and ligand for Orexin Receptor-1 (OR1), isolated from a small
group of hypothalamic neurons. OXA orchestrates different brain functions, and at the cognitive level some of the effects
of insufficiency of OXA are well-known, for example in Parkinson’s disease. It is widely assumed that deteriorated cognitive
processes are related to impaired network connectivity. However, little is known about the effects of OXA in network connectivity
and synaptogenesis. Therefore, to obtain insight into this problem we designed experiments with two groups of networks of
dissociated cortical neurons: one group incubated in a plain medium and another chronically treated with OXA. After 1, 2,
3 or 4 weeks in vitro we applied immunocytochemistry for detection of OXA, OR1, and synaptic marker synaptophysin. Shortly
after plating, 91 ± 8% of the neurons cultivated in a plain medium expressed OXA-immunoreactivity, which does normally not
occur in vivo indicating that neurons may change their phenotype under non-natural culture conditions to develop synaptically
coupled networks. The fraction of orexinergic neurons decreased to 33 ± 21% after 4 weeks in vitro. OXA expression was highest
in the first week of network formation, the period of maximum synaptogenesis, and then decreased and stabilized in the weeks
thereafter. Our hypothesis that OXA plays a role in the network development as a synaptogenic factor was supported by higher
levels, earlier onset, and sustained increase of synaptophysin expression in experiments with chronic OXA application to the
culture medium. 相似文献
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脂蛋白(a)[Lp(a)]是一种与低密度脂蛋白类似的脂蛋白,其特殊处在于多含一种具明显多态性的糖蛋白──载脂蛋白(a)[Apo(a)]。Apo(a)与血浆纤溶酶原有很大同源性。Lp(a)由肝合成,其分解可能主要经非特异途径。Apo(a)大小及血浆Lp(a)浓度主要由Apo(a)基因决定。Lp(a)易沉积于血管壁,并可促进平滑肌细胞生长及抑制纤维蛋白溶解,这可能是其促动脉粥样硬化和血栓形成的机理所在。Lp(a)的生理功能尚不清楚。 相似文献
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Jan Krumsiek Karsten Suhre Anne M. Evans Matthew W. Mitchell Robert P. Mohney Michael V. Milburn Brigitte W?gele Werner R?misch-Margl Thomas Illig Jerzy Adamski Christian Gieger Fabian J. Theis Gabi Kastenmüller 《PLoS genetics》2012,8(10)
Recent genome-wide association studies (GWAS) with metabolomics data linked genetic variation in the human genome to differences in individual metabolite levels. A strong relevance of this metabolic individuality for biomedical and pharmaceutical research has been reported. However, a considerable amount of the molecules currently quantified by modern metabolomics techniques are chemically unidentified. The identification of these “unknown metabolites” is still a demanding and intricate task, limiting their usability as functional markers of metabolic processes. As a consequence, previous GWAS largely ignored unknown metabolites as metabolic traits for the analysis. Here we present a systems-level approach that combines genome-wide association analysis and Gaussian graphical modeling with metabolomics to predict the identity of the unknown metabolites. We apply our method to original data of 517 metabolic traits, of which 225 are unknowns, and genotyping information on 655,658 genetic variants, measured in 1,768 human blood samples. We report previously undescribed genotype–metabotype associations for six distinct gene loci (SLC22A2, COMT, CYP3A5, CYP2C18, GBA3, UGT3A1) and one locus not related to any known gene (rs12413935). Overlaying the inferred genetic associations, metabolic networks, and knowledge-based pathway information, we derive testable hypotheses on the biochemical identities of 106 unknown metabolites. As a proof of principle, we experimentally confirm nine concrete predictions. We demonstrate the benefit of our method for the functional interpretation of previous metabolomics biomarker studies on liver detoxification, hypertension, and insulin resistance. Our approach is generic in nature and can be directly transferred to metabolomics data from different experimental platforms. 相似文献
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Maureen Fuary 《The Australian journal of anthropology》1997,8(1):247-258
This paper considers the significance of the novel Drums of Mer (1941) in contemporary Torres Strait Islanders' lives. Its use as narrative by many Islanders today constitutes one means by which men especially have come to know themselves, white others, and their past. In particular, I explore the ways in which this story appeals to and is appealed to by Yam Island people. Contrary to literary deconstructions of Idriess's representations of Aboriginal and Torres Strait Islander people, my paper argues that in seriously attending to Torres Strait readings of Drums of Mer we can see that for contemporary Islander readers, it is not themselves who are other but rather the white protagonists. I employ Said's (1994) notion of ‘cultural overlap’ and de Certeau's (1988) understandings of reading and writing as ‘everyday practices’ to frame my analysis of the differing impacts of the historical novel, Drums of Mer, and the Reports of the Cambridge Anthropological Expedition to Torres Straits. It is through story telling that Yam Island selves are placed in the past and the present, and in Idriess's memorable story a similar effect is achieved. In his novel approach, the past becomes his-story, a romanticised refraction of the Reports. Unlike the Reports, this novel is a sensual rendering of a Torres Strait past, and at this level it operates as a mnemonic device for Yam Island people, triggering memories and the imagination through the senses. This Torres Strait Islander detour by way of a past via a story, can be understood as a means by which Yam Island people continue to actively produce powerful images of themselves, for both themselves and for others. 相似文献
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Ana Márquez Roser Solans José Hernández-Rodríguez Maria C. Cid Santos Casta?eda Marc Ramentol Luis Rodriguez-Rodriguez Javier Narváez Ricardo Blanco Norberto Ortego-Centeno Spanish GCA Consortium ?yvind Palm Andreas P. Diamantopoulos Niko Braun Frank Moosig Torsten Witte Lorenzo Beretta Claudio Lunardi Marco A. Cimmino Augusto Vaglio Carlo Salvarani Miguel A. González-Gay Javier Martín 《PloS one》2014,9(11)
Introduction
Increased expression of IL-33 and its receptor ST2, encoded by the IL1RL1 gene, has been detected in the inflamed arteries of giant cell arteritis (GCA) patients. The aim of the present study was to investigate for the first time the potential influence of the IL33 and IL1RL1 loci on GCA predisposition.Methods
A total of 1,363 biopsy-proven GCA patients and 3,908 healthy controls from four European cohorts (Spain, Italy, Germany and Norway) were combined in a meta-analysis. Six genetic variants: rs3939286, rs7025417 and rs7044343, within the IL33 gene, and rs2058660, rs2310173 and rs13015714, within the IL1RL1 gene, previously associated with immune-related diseases, were genotyped using predesigned TaqMan assays.Results
A consistent association between the rs7025417 polymorphism and GCA was evident in the overall meta-analysis, under both allele (PMH = 0.041, OR = 0.88, CI 95% 0.78–0.99) and recessive (PMH = 3.40E-03, OR = 0.53, CI 95% 0.35–0.80) models. No statistically significant differences between allele or genotype frequencies for the other IL33 and IL1RL1 genetic variants were detected in this pooled analysis.Conclusions
Our results clearly evidenced the implication of the IL33 rs7025417 polymorphism in the genetic network underlying GCA. 相似文献17.
Gamal M. K. Mehaisen Ayman M. Saeed Ahmed Gad Ahmed O. Abass Mahmoud Arafa Ashraf El-Sayed 《PloS one》2015,10(10)
Embryo cryopreservation remains an important technique to enhance the reconstitution and distribution of animal populations with high genetic merit. One of the major detrimental factors to this technique is the damage caused by oxidative stress. Melatonin is widely known as an antioxidant with multi-faceted ways to counteract the oxidative stress. In this paper, we investigated the role of melatonin in protecting rabbit embryos during preimplantation development from the potential harmful effects of oxidative stress induced by in vitro culture or vitrification. Rabbit embryos at morula stages were cultured for 2 hr with 0 or 10−3 M melatonin (C or M groups). Embryos of each group were either transferred to fresh culture media (CF and MF groups) or vitrified/devitrified (CV and MV groups), then cultured in vitro for 48 hr until the blastocyst stage. The culture media were used to measure the activity of antioxidant enzymes: glutathione-s-transferase (GST) and superoxide dismutase (SOD), as well as the levels of two oxidative substrates: lipid peroxidation (LPO) and nitric oxide (NO). The blastocysts from each group were used to measure the expression of developmental-related genes (GJA1, POU5F1 and Nanog) and oxidative-stress-response-related genes (NFE2L2, SOD1 and GPX1). The data showed that melatonin promoted significantly (P<0.05) the blastocyst rate by 17% and 12% in MF and MV groups compared to their controls (CF and CV groups). The GST and SOD activity significantly increased by the treatment of melatonin in fresh or vitrified embryos, while the levels of LPO and NO decreased (P<0.05). Additionally, melatonin considerably stimulated the relative expression of GJA1, NFE2L2 and SOD1 genes in MF and MV embryos compared to CF group. Furthermore, melatonin significantly ameliorated the reduction of POU5F1 and GPX1 expression induced by vitrification. The results obtained from the current investigation provide new and clear molecular aspects regarding the mechanisms by which melatonin promotes development of both fresh and vitrified rabbit embryos. 相似文献
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Hafiz Muhammad Ahmad Xiukang Wang Munazza Ijaz Mahmood-Ur-Rahman Sadaf Oranab Muhammad Amjad Ali Sajid Fiaz 《Current issues in molecular biology》2022,44(8):3695
Phytohormones play an essential role in plant growth and development in response to environmental stresses. However, plant hormones require a complex signaling network combined with other signaling pathways to perform their proper functions. Thus, multiple phytohormonal signaling pathways are a prerequisite for understanding plant defense mechanism against stressful conditions. MicroRNAs (miRNAs) are master regulators of eukaryotic gene expression and are also influenced by a wide range of plant development events by suppressing their target genes. In recent decades, the mechanisms of phytohormone biosynthesis, signaling, pathways of miRNA biosynthesis and regulation were profoundly characterized. Recent findings have shown that miRNAs and plant hormones are integrated with the regulation of environmental stress. miRNAs target several components of phytohormone pathways, and plant hormones also regulate the expression of miRNAs or their target genes inversely. In this article, recent developments related to molecular linkages between miRNAs and phytohormones were reviewed, focusing on drought stress. 相似文献