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71.
Lisa Noelle Cooper J. G.M. Thewissen Sunil Bajpai B. N. Tiwari 《Historical Biology》2013,25(3):279-310
Raoellids are small, raccoon-sized Eocene artiodactyls, closely related to archaic cetaceans (archaeocetes) that have poor representation of postcranial elements in the fossil record. Little is known of the aquatic and terrestrial locomotor affinities of raoellids due to the paucity of their fossil record, leaving a critical gap in our understanding of the earliest portion of the artiodactyl marine invasion. To address this gap, a comparative morphological analysis of the postcranial elements was undertaken based on newly recovered elements of the raoellid Indohyus, archaeocetes and extant artiodactyls. Greater than 200 postcranial elements of Indohyus were described, and some limb element cross-sections were visualised via paleohistological thin sections and CT scans. Results show that during terrestrial locomotion, Indohyus probably had a digitigrade posture and mediolaterally stabilised limbs that functioned mostly in flexion and extension within the parasagittal plane. Quantification of midshaft cross-sectional area for some elements of Indohyus showed an osteosclerotic cortex, a skeletal characteristic associated with aquatic behaviours. Indohyus may represent a critical intermediate in the evolution of the cetacean terrestrial-to-aquatic body plan, as it bears gracile postcranial element proportions similar to a terrestrial artiodactyl but also an incipient form of osteosclerosis compared to pakicetid archaeocetes. 相似文献
72.
Jan Rupp Lisa Pfleiderer Christiane Jugert Sonja Moeller Matthias Klinger Klaus Dalhoff Werner Solbach Steffen Stenger Tamas Laskay Ger van Zandbergen 《PloS one》2009,4(6)
Background
Intracellular pathogens have developed elaborate strategies for silent infection of preferred host cells. Chlamydia pneumoniae is a common pathogen in acute infections of the respiratory tract (e.g. pneumonia) and associated with chronic lung sequelae in adults and children. Within the lung, alveolar macrophages and polymorph nuclear neutrophils (PMN) are the first line of defense against bacteria, but also preferred host phagocytes of chlamydiae.Methodology/Principal Findings
We could show that C. pneumoniae easily infect and hide inside neutrophil granulocytes until these cells become apoptotic and are subsequently taken up by macrophages. C. pneumoniae infection of macrophages via apoptotic PMN results in enhanced replicative activity of chlamydiae when compared to direct infection of macrophages, which results in persistence of the pathogen. Inhibition of the apoptotic recognition of C. pneumoniae infected PMN using PS- masking Annexin A5 significantly lowered the transmission of chlamydial infection to macrophages. Transfer of apoptotic C. pneumoniae infected PMN to macrophages resulted in an increased TGF-ß production, whereas direct infection of macrophages with chlamydiae was characterized by an enhanced TNF-α response.Conclusions/Significance
Taken together, our data suggest that C. pneumoniae uses neutrophil granulocytes to be silently taken up by long-lived macrophages, which allows for efficient propagation and immune protection within the human host. 相似文献73.
Manuel Garber Michael C Zody Harindra M Arachchi Aaron Berlin Sante Gnerre Lisa M Green Niall Lennon Chad Nusbaum 《Genome biology》2009,10(6):R60-6
The most recent release of the finished human genome contains 260 euchromatic gaps (excluding chromosome Y). Recent work has
helped explain a large number of these unresolved regions as 'structural' in nature. Another class of gaps is likely to be
refractory to clone-based approaches, and cannot be approached in ways previously described. We present an approach for closing
these gaps using 454 sequencing. As a proof of principle, we closed all three remaining non-structural gaps in chromosome
15. 相似文献
74.
75.
Farias SE Basselin M Chang L Heidenreich KA Rapoport SI Murphy RC 《Journal of lipid research》2008,49(9):1990-2000
Inflammatory lipid mediators derived from arachidonic acid (AA) and docosahexaenoic acid (DHA) modify the pathophysiology of brain ischemia. The goal of this work was to investigate the formation of eicosanoids and docosanoids generated from AA and DHA, respectively, during no-flow cerebral ischemia. Rats were subjected to head-focused microwave irradiation 5 min following decapitation (complete ischemia) or prior to decapitation (controls). Brain lipids were extracted and analyzed by reverse-phase liquid chromatography-tandem mass spectrometry. After complete ischemia, brain AA, DHA, and docosapentaenoic acid concentrations increased 18-, 5- and 4-fold compared with controls, respectively. Prostaglandin E(2) (PGE(2)) and PGD(2) could not be detected in control microwaved rat brain, suggesting little endogenous PGE(2)/D(2) production in the brain in the absence of experimental manipulation. Concentrations of thromboxane B(2), E(2)/D(2)-isoprostanes, 5-hydroxyeicosatetraenoic acid (5-HETE), 5-oxo-eicosatetraenoic acid, and 12-HETE were significantly elevated in ischemic brains. In addition, DHA products such as mono-, di- and trihydroxy-DHA were detected in control and ischemic brains. Monohydroxy-DHA, identified as 17-hydroxy-DHA and thought to be the immediate precursor of neuroprotectin D(1), was 6.5-fold higher in ischemic than in control brain. The present study demonstrated increased formation of eicosanoids, E(2)/D(2)-IsoPs, and docosanoids following cerebral ischemia. A balance of these lipid mediators may mediate immediate events of ischemic injury and recovery. 相似文献
76.
Spectral karyotyping refines cytogenetic diagnostics of constitutional chromosomal abnormalities 总被引:12,自引:0,他引:12
E. Schröck T. Veldman Hesed Padilla-Nash Y. Ning Jack Spurbeck Syed Jalal Lisa G. Shaffer Peter Papenhausen Chahira Kozma Mary C. Phelan Eigil Kjeldsen Stephen A. Schonberg Patricia O’Brien Les Biesecker Stan du Manoir Thomas Ried 《Human genetics》1997,101(3):255-262
Karyotype analysis by chromosome banding is the standard method for identifying numerical and structural chromosomal aberrations
in pre- and postnatal cytogenetics laboratories. However, the chromosomal origins of markers, subtle translocations, or complex
chromosomal rearrangements are often difficult to identify with certainty. We have developed a novel karyotyping technique,
termed spectral karyotyping (SKY), which is based on the simultaneous hybridization of 24 chromosome-specific painting probes
labeled with different fluorochromes or fluorochrome combinations. The measurement of defined emission spectra by means of
interferometer-based spectral imaging allows for the definitive discernment of all human chromosomes in different colors.
Here, we report the comprehensive karyotype analysis of 16 samples from different cytogenetic laboratories by merging conventional
cytogenetic methodology and spectral karyotyping. This approach could become a powerful tool for the cytogeneticists, because
it results in a considerable improvement of karyotype analysis by identifying chromosomal aberrations not previously detected
by G-banding alone. Advantages, limitations, and future directions of spectral karyotyping are discussed.
Received: 4 August 1997 / Accepted: 8 September 1997 相似文献
77.
78.
Background
In the past few years, both automated and manual high-throughput protein expression and purification has become an accessible means to rapidly screen and produce soluble proteins for structural and functional studies. However, many of the commercial vectors encoding different solubility tags require different cloning and purification steps for each vector, considerably slowing down expression screening. We have developed a set of E. coli expression vectors with different solubility tags that allow for parallel cloning from a single PCR product and can be purified using the same protocol. 相似文献79.
Nina Kaludercic Andrea CarpiRoberta Menabò Fabio Di Lisa Nazareno Paolocci 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2011,1813(7):1323-1332
Recent evidence highlights monoamine oxidases (MAO) as another prominent source of oxidative stress. MAO are a class of enzymes located in the outer mitochondrial membrane, deputed to the oxidative breakdown of key neurotransmitters such as norepinephrine, epinephrine and dopamine, and in the process generate H2O2. All these monoamines are endowed with potent modulatory effects on myocardial function. Thus, when the heart is subjected to chronic neuro-hormonal and/or peripheral hemodynamic stress, the abundance of circulating/tissue monoamines can make MAO-derived H2O2 production particularly prominent. This is the case of acute cardiac damage due to ischemia/reperfusion injury or, on a more chronic stand, of the transition from compensated hypertrophy to overt ventricular dilation/pump failure. Here, we will first briefly discuss mitochondrial status and contribution to acute and chronic cardiac disorders. We will illustrate possible mechanisms by which MAO activity affects cardiac biology and function, along with a discussion as to their role as a prominent source of reactive oxygen species. Finally, we will speculate on why MAO inhibition might have a therapeutic value for treating cardiac affections of ischemic and non-ischemic origin. This article is part of a Special Issue entitled: Mitochondria and Cardioprotection. 相似文献
80.
Contrasting patterns of Andean diversification among three diverse clades of Neotropical clearwing butterflies 下载免费PDF全文
Nicolas Chazot Donna Lisa De‐Silva Keith R. Willmott André V. L. Freitas Gerardo Lamas James Mallet Carlos E. Giraldo Sandra Uribe Marianne Elias 《Ecology and evolution》2018,8(8):3965-3982
The Neotropical region is the most biodiverse on Earth, in a large part due to the highly diverse tropical Andean biota. The Andes are a potentially important driver of diversification within the mountains and for neighboring regions. We compared the role of the Andes in diversification among three subtribes of Ithomiini butterflies endemic to the Neotropics, Dircennina, Oleriina, and Godyridina. The diversification patterns of Godyridina have been studied previously. Here, we generate the first time‐calibrated phylogeny for the largest ithomiine subtribe, Dircennina, and we reanalyze a published phylogeny of Oleriina to test different biogeographic scenarios involving the Andes within an identical framework. We found common diversification patterns across the three subtribes, as well as major differences. In Dircennina and Oleriina, our results reveal a congruent pattern of diversification related to the Andes with an Andean origin, which contrasts with the Amazonian origin and multiple Andean colonizations of Godyridina. In each of the three subtribes, a clade diversified in the Northern Andes at a faster rate. Diversification within Amazonia occurred in Oleriina and Godyridina, while virtually no speciation occurred in Dircennina in this region. Dircennina was therefore characterized by higher diversification rates within the Andes compared to non‐Andean regions, while in Oleriina and Godyridina, we found no difference between these regions. Our results and discussion highlight the importance of comparative approaches in biogeographic studies. 相似文献