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Dias, Ana Carla da Silva Carvalho. "Efeito protetor da fucoidina, um inibidor de P e L-selectina, na resposta inflamatÃria sistÃmica e distÃrbios de motilidade gastrintestinal na pancreatite aguda experimental." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10774.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorIntroduÃÃo e objetivos: Os neutrÃfilos desempenham importante papel na pancreatite aguda grave. InfiltraÃÃo de neutrÃfilos no pÃncreas à um processo complexo, coordenado por molÃculas de adesÃo especÃficas, tais como a P-selectina. Fucoidina à um polissacarÃdeo sulfatado que bloqueia a funÃÃo da L-e P-selectinas. No presente estudo avaliamos se o tratamento com fucoidina poderia impedir a infiltraÃÃo de neutrÃfilos e, assim, reverter a inflamaÃÃo sistÃmica e dismotilidades gastrintestinais associadas à pancreatite aguda grave. MÃtodos: A pancreatite aguda foi induzida em camundongos Swiss pela infusÃo retrÃgrada de Ãcido taurolitocÃlico (3,0%) (TLC-S) no ducto pancreÃtico ou por injeÃÃes intraperitoneais de ceruleÃna (50 Âg/kg/h). Os grupos experimentais receberam fucoidina (25 mg/kg, iv) antes da induÃÃo da pancreatite, e os grupos de controle receberam apenas soluÃÃo salina. ApÃs 24 horas, os nÃveis sÃricos de amilase, lipase, IL-1β, TNF-α, nitrito e de malondialdeÃdo (MDA) pancreÃtico foram medidos. AlÃm disso, a atividade de mieloperoxidase (MPO) (pulmÃo, pÃncreas, estÃmago e jejuno) e avaliaÃÃo histolÃgica (pÃncreas) foram determinadas. O esvaziamento gÃstrico e trÃnsito gastrintestinal foram medidos pelo mÃtodo de centro geomÃtrico. A contratilidade gastrintestinal in vitro foi registrada atravÃs de transdutores de forÃa conectados a sistema computadorizado de aquisiÃÃo de dados. Carbacol (0,01 ÂM - 30 ÂM), KCl 60 mM e estimulaÃÃo elÃctrica (0,5-8,0 Hz; 1ms, 40 V), foram aplicados sobre o fundo gÃstrico e jejuno dos animais 24 horas apÃs a pancreatite induzida por TLC-S. Resultados: Os nÃveis de MDA pancreÃtico, amilase, lipase, nitrito, TNF-α e IL-1β sÃricos, bem como MPO pancreÃtica e pulmonar estavam aumentados tanto no modelo de pancreatite aguda induzida por TLCS quanto no modelo ceruleÃna quando comparado aos grupos controle correspondentes. Fucoidina reduziu significativamente os nÃveis aumentados de amilase, lipase, MPO pancreÃtica e pulmonar, MDA, TNF-α, IL-1β e nitrito em ambos os modelos de pancreatite aguda. As mudanÃas histolÃgicas observadas no pÃncreas em ambos os modelos foram significativamente atenuadas pela fucoidina. O modelo de pancreatite aguda induzida por TLC-S induziu retardo no esvaziamento gÃstrico e trÃnsito gastrointestinal, aumento de MPO no estÃmago e no jejuno, alÃm de hipercontratilidade de jejuno in vitro. Fucoidina reverteu significativamente os distÃrbios gastrintestinais in vivo e in vitro e os nÃveis aumentados de MPO gÃstrica e jejunal induzidos pela injeÃÃo de TLC-S. ConclusÃo: Fucoidina reduziu a gravidade da pancreatite aguda experimental atravÃs da diminuiÃÃo da infiltraÃÃo de neutrÃfilos, inflamaÃÃo sistÃmica e dismotilidades gastrintestinais, sugerindo que a modulaÃÃo das selectinas, pode constituir uma abordagem terapÃutica promissora para pancreatite aguda.
Background & Aims: Neutrophils play a critical role in severe acute pancreatitis. Tissue infiltration of neutrophils in the pancreas is a multistep process, coordinated by specific adhesion molecules, such as P-selectin. Fucoidin is a sulphated fucosylated polysaccharide that binds to and blocks the function of L- and P-selectins, and the present study has evaluated whether fucoidin treatment could prevent neutrophil infiltration, and thereby reverse the systemic inflammation and gastrointestinal dysmotility associated with severe acute pancreatitis. Methods: Acute pancreatitis was induced in Swiss mice either by the retrograde infusion of taurolithocholic acid (3.0%) (TLC-S) into the pancreatic duct or by intraperitoneal injections of cerulein (50 Âg/kg/h). The experimental groups received fucoidan (25 mg/kg, i.v.) before pancreatitis induction whist control groups received only saline. After 24 hours, pancreatic malondialdehyde (MDA), serum amylase, lipase, IL-1β, TNF- and nitrite were measured. In addition, myeloperoxidase (MPO) activity (lung, pancreas, stomach and jejunum) and histological assessment (pancreas) were determined. Gastric emptying and gastrointestinal transit (using the geometric center method) were also measured. Gastrointestinal contractility in vitro was recorded through force transducers coupled to a computerized data acquisition system, carbachol (0,01 ÂM â 30 ÂM), KCl 60mM and electrical field stimulation (0.5-8.0 Hz; 1ms; 40 V), was applied on gastric fundus and jejunum of mice 24 hours after TLC-S induced pancreatitis. Results: Pancreatic MDA, serum amylase, lipase, nitrite, TNF- and IL-1β, pancreatic and lung MPO, were increased in both TLCS- and cerulein acute pancreatitis compared with respective control groups. Fucoidan significantly decreased the augmented levels of amylase, lipase, pancreatic and lung MPO, MDA, TNF-, IL-1β and nitrite in both acute pancreatitis models. Pancreas histological changes observed in both models were significantly attenuated by fucoidan. The acute pancreatitis model induced by TLC-S caused delayed gastric emptying and gastrointestinal transit, incresead gastric and jejunum MPO, and jejunum hypercontractility in vitro. Fucoidan significantly reversed the gastrointestinal disorders in vivo and in vitro and augmented levels of gastric and jejunum MPO induced by TLC-S. Conclusion: Fucoidan reduced the severity of acute pancreatitis in mice by decreasing neutrophil infiltration, systemic inflammation and gastrointestinal dysmotility, suggesting that modulation of selectins may constitute a promising therapeutic approach for acute pancreatitis.
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Fraser, Stuart Tallis. "Lectin - carbohydrate interactions in lympho-haemopoiesis: a study of L-selectin, ligands of L-selectin and CD24 inthe rat." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31236844.
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Fraser, Stuart Tallis. "Lectin - carbohydrate interactions in lympho-haemopoiesis : a study of L-selectin, ligands of L-selectin and CD24 in the rat /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20667450.
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Newman, Andrew. "The regulation of L-selectin activity by proteolysis." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/103855/.
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L-selectin (CD62L) is a type I transmembrane protein expressed by lymphocytes which directs their migration from the bloodstream into lymph nodes and infected tissues. Stimulation of the T cell receptor (TCR) activates the enzyme A Disintegrin and Metalloproteinase 17 (ADAM 17), which cleaves L-selectin at the ectodomain generating a metalloproteinase product (MP product) comprising of a transmembrane region and a 17-amino acid intracellular domain (ICD). ϒ-secretase is a multi-subunit protease that cleaves up to 90 identified type I transmembrane proteins in the intramembrane region following ectodomain proteolysis by metalloproteinases. Presenilin (PS), the catalytic component of γ-secretase is activated during an intramolecular cleavage called endoproteolysis separating the carboxy (C) and amino (N) termini. The catalytically active C-terminal fragment of PS then induces intramembrane proteolysis of substrates. The aim of my thesis was to firstly determine whether the MP product of L-selectin was a substrate for PS. Subsequently, I analysed whether stimulation of the TCR activates PS, inducing intramembrane proteolysis of the MP product releasing the ICD into the intracellular region. My data showed for the first time that in a resting T-cell, L-selectin forms a multi-component complex with both ADAM 17 and PS. TCR-activation induces ADAM 17 dependent proteolysis of L-selectin generating an MP product. Stimulation of the TCR also causes endoproteolysis of PS, where activated PS then cleaves the bound MP product. After PS cleavage, the released ICD was unstable and therefore difficult to detect, however I was able to block its formation using either PS inhibitor treatment or generating I351W mutated L-selectin, which was resistant to intramembrane proteolysis.
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Killock, David James. "Molecular characterisation of L-selectin-dependent adhesion and signalling." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512055.
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Tanousis, Kyriakos Michael. "The role of L-selectin shedding in regulating lymphocyte migration." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368043.
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Smith, Tracy L. "The Effect of Anticoagulants on White Blood Cell L-selectin Levels." Youngstown State University / OhioLINK, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=ysu997725968.
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Nicholson, Martin William Michael. "Molecular analysis of the leukocyte cell-surface adhesion protein L-selectin." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260752.
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Gräfe, Michael. "Die Bedeutung entzündlicher Reaktionen für die Pathogenese der Arteriosklerose." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2001. http://dx.doi.org/10.18452/13763.
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Während die zellulären Mechanismen der Pathogenese der Arteriosklerose intensiv untersucht worden sind, ist über die Mechanismen, die zu einer bevorzugten Lokalisation arteriosklerotischer Läsionen in bestimmten Gefäßarealen führen, weniger bekannt. Zur Untersuchung dieser Mechanismen wurden Endothelzellen aus menschlichen Koronararterien, einem Gefäßbereich, in dem häufig arteriosklerotische Läsionen beobachtete werden, isoliert und kultiviert. Endothelzellen der Mikrozirkulation menschlicher Herzen wurden unter gleichen Bedingungen kultiviert und die Reaktionen beider Zellarten verglichen. Inkubation der Zellen mit den in Bezug auf die Bildung arteriosklerotischer Plaques besonders pathogenen oxidierten LDL induzierte in makrovaskulären koronaren Endothelzellen eine stärkere Zunahme der PAI-1 Aktivität (182%, pWhile the cellular mechanisms of atherosclerosis have been intensively studied, the mechanisms leading to preferential localization of atherosclerotic lesions are less well understood. To further define these mechanisms, endothelial cells from coronary arteries, i.e. vessels with frequent atherosclerotic lesions, were isolated and grown in vitro. In order to compare the reactions of both cell types, endothelial cells derived from microvessels of human hearts were isolated and cultured under identical conditions. Incubation of endothelial cells with oxidized LDL (75 µg/ml protein) induced a significant increase in PAI-1 activity (182 %, p
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Kilian, Karin. "Identification of novel interaction partners for the leukocyte adhesion molecule L-selectin." [S.l. : s.n.], 2002. http://www.diss.fu-berlin.de/2002/295/index.html.
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Carlson, Grady E. "Dynamic Biochemical Tissue Analysis of L-selectin Ligands on Colon Cancer Tissues." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1343932605.
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Rzeniewicz, Karolina Anna. "Understanding the biological significance of L-selectin shedding during leukocyte transendothelial migration." Thesis, King's College London (University of London), 2014. https://kclpure.kcl.ac.uk/portal/en/theses/understanding-the-biological-significance-of-lselectin-shedding-during-leukocyte-transendothelial-migration(83c23b64-7833-4488-82d9-9e47732ac690).html.
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Inflammation is a response of the immune and vascular systems to the stimuli perceived as harmful to the host. Inflammation can be acute or chronic, and the recruitment of leukocytes to the affected tissues is a fundamental process during the course of both these events. Leukocytes are recruited in a process known as the multi-step adhesion cascade, which is a highly co-ordinated series of adhesive events mediated by the cell adhesion molecules (CAMs) on both leukocytes and endothelial cells. L-selectin is a CAM involved in the initial stages of the cascade, i.e. tethering and rolling, although there is a mounting body of evidence that points towards its role at later stages of the cascade, such as chemotaxis beyond transendothelial migration (TEM). The work outlined in this thesis explores the possibility that L-selectin actively contributes to TEM in monocytes. There are two important and measurable properties of L-selectin: (i) its rapid proteolysis (or “shedding”) upon cell activation, and (ii) its transition from being monomeric in the plasma membrane to being clustered, following ligand binding, which is a hallmark of downstream signalling. By expressing C-terminally green fluorescent protein (GFP)-tagged L-selectin in THP-1 monocytes, it was possible for the first time to monitor and analyse the spatio-temporal distribution of L-selectin and its shedding during TEM. In addition, co-expressing L-selectin-GFP with L-selectin tagged to red fluorescent protein (RFP) enabled measurement of L-selectin clustering during TEM via the use of fluorescence lifetime imaging microscopy (FLIM) to monitor Forster resonance energy transfer (FRET) between the GFP and RFP-tags. Interestingly, the majority of L-selectin was found to be clustered exclusively in pseudopods protruding beneath the endothelial monolayer, where L-selectin ligands are known to exist. L-selectin clustering was also found to occur following cross-linking of either CD43 or PECAM-1, suggesting inside-out signalling is an important factor in modulating L-selectin function. Moreover, both the extracellular cleavage domain and two cytoplasmic tail serine residues were involved in fundamentally regulating L-selectin clustering. Finally, the sub-cellular distribution of L-selectin clustering correlated tightly with the dynamics of the pseudopods that protruded beneath the endothelial monolayer during TEM. This thesis aims to understand the contribution that L-selectin has during the later stages of the adhesion cascade, and will re-shape the currently held perspective that this cell adhesion molecule’s role is solely restricted to just tethering and rolling.
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Newe, Abigail Lucy. "Unearthing the molecular mechanisms that govern L-selectin-dependent adhesion and migration." Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/unearthing-the-molecular-mechanisms-that-govern-lselectindependent-adhesion-and-migration(8f22370e-34b7-447f-98c2-dd1713036a84).html.
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L-selectin has been well characterised as a cell adhesion molecule, which plays a role in the recruitment of leukocytes to sites of inflammation and is responsible for the recirculation of lymphocytes to secondary lymphoid organs. Recent evidence has shown that L-selectin also acts as a signalling molecule to activate pathways and regulate the inflammatory response. The cytosolic tail of L-selectin plays a crucial role in regulating its activity through its interaction with binding partners, such as calmodulin (CaM) and the ERM protein family. However, little is known about how the interaction between L-selectin and its binding partners is regulated. The aim of this multidisciplinary PhD project is to use biophysical and cell biological methods to address the role of the interaction between L-selectin and its binding partners during leukocyte recruitment. To this end, the interaction between CaM and the L-selectin cytosolic tail was assessed using isothermal titration calorimetry (ITC) and nuclear magnetic resonance (NMR) spectroscopy. Analysis revealed that phosphorylation of serine residues within the cytosolic tail of L-selectin did not affect CaM binding. To enable the observation of the interaction between L-selectin and CaM whilst leukocytes are undergoing transendothelial migration (TEM), the THP-1 monocytic cell line was engineered to stably express L-selectin-GFP and CaM-RFP so their interaction could be monitored at different stages of TEM. The data showed that phosphorylation of serine 364 in the L-selectin tail is important for regulating CaM interaction. Discrepancies were identified between the biophysical and cell biological results, implying the leukocyte plasma membrane may play a vital role in regulating the interaction between L-selectin and CaM. This highlights the importance of studying transmembrane proteins in the correct context.
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Gu, Baijun. "TWO PATHWAYS OF SHEDDING OF L-SELECTIN AND CD23 FROM HUMAN B-LYMPHOCYTES." University of Sydney, 2000. http://hdl.handle.net/2123/821.
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Lymphocytes from patients with B-chronic lymphocytic leukemia (B-CLL) express large numbers of P2X7 receptors for extracellular adenosine triphosphate (ATP). Activation of P2X7 receptors induces multiple downstream effects, of which the best documented is the opening of an ionic channel that is selective for divalent cations. Another effect of ATP is to induce the shedding of L-selectin (CD62L), a molecule which is involved in the adhesive interactions of lymphocytes on endothelial cells. High levels of soluble L-selectin and CD23 are found in the serum of patients with B-CLL, although the mechanisms involved in their production are poorly characterized. Because extracellular ATP causes shedding of L-selectin, we studied the effect of ATP on shedding of CD23, an adhesion molecule expressed on the surface of B-CLL lymphocytes. ATP induced the shedding of CD23 at an initial rate of 12% of that for L-selectin, while the EC50 of ATP (35 uM) and BzATP (10 uM) was identical for shedding of both molecules. Inactivation of the P2X7 receptor by pre-incubation with OxATP, an irreversible inhibitor of P2X7 purinoceptor, abolished ATP-induced shedding of both molecules. Moreover, KN-62, the most potent inhibitor for the P2X7 receptor inhibited ATP-induced shedding of both CD23 and L-selectin with the same IC50 (12 nM). Ro 31-9790, a membrane permeant zinc chelator which inhibits the phorbol-ester stimulated shedding of L-selectin also inhibited shedding of CD23 from B-CLL lymphocytes, but the IC50 was different for the two shed molecules (25 versus 1 ug/ml respectively). Although L-selectin was completely shed by incubation of cells with phorbol-ester no CD23 was lost under these conditions. Also, Ca2+ inhibits ATP-induced CD23 shedding but not L-selectin shedding. Since soluble CD23 and L-selectin are found in the serum of normal subjects and B-CLL patients, the expression of these two adhesion molecules on lymphocytes before and after transendothelial migration was studied in an in vitro model of this process. In normal and B-CLL subjects, 71�b5% of L-selectin from both T and B cells and 90% of CD23 from B cells was lost following transmigration, while the expression of a range of other adhesion molecules such as VLA-4, ICAM-1, LFA-1 and CD44 was unchanged. Lymphocytes incubated with OxATP retained their capacity for transendothelial migration and showed the same loss of L-selectin as control leukaemic lymphocytes. Ro 31-9790, which can protect ATP-induced both L-selectin and CD23 shedding, had no effect on inhibiting L-selectin and CD23 lost during transmigration. These data show the presence of a second pathway for the downregulation of L-selectin and CD23 from the lymphocyte surface. Data in vivo from 'knock-out' mice show that L-selectin is essential for the emigration of lymphocytes through high endothelial venules into lymph nodes. The migration of normal and B-CLL lymphocytes across confluent human umbilical vein endothelial monolayers was studied in an in vitro model of this process. Lymphocytes treated with ATP or BzATP showed 56�b25% or 67�b16% loss of L-selectin on the surface and 36�b24% or 64�b19% decrease of transmigration, respectively, while OxATP, which does not alter the L-selectin level, had no effect on lymphocyte transmigration. Further experiments examined this correlation between L-selectin expression and lymphocyte transendothelial migration in this model system. A quantitative assay for cell surface L-selectin showed that expression of L-selectin was lower on B-CLL lymphocytes (8,880�b5,700 molecules/cell) than on normal lymphocytes (29,500�b7,500 molecules/cell, p less than 0.001). Also the rate of transmigration of B-CLL lymphocytes (1.5�b0.9 migrated cells/HUVEC) was lower than normal peripheral lymphocytes (2.4�b0.9 migrated cells/HUVEC, p=0.04). Incubation of lymphocytes in complete medium for 24 hrs increased the expression of L-selectin on B-CLL lymphocytes by 1.5 to 2 fold while the normal lymphocyte L-selectin remained at the initial level. This upregulation of B-CLL L-selectin correlated with a 2 fold increased rate of transendothelial migration. A correlation was found between L-selectin expression on lymphocytes and their ability for transendothelial migration (r^2=0.6). This study shows that the adhesion molecules L-selectin and CD23 can be lost from lymphocytes by two different physiological pathways. One is by P2X7 receptor activation by extracellular ATP while the second is activated by transendothelial migration of these cells. A second finding is that B-CLL lymphocytes have lower level of L-selectin expression and an impaired ability for transendothelial migration compared with normal peripheral blood lymphocytes. Do these results explain the high serum levels of soluble L-selectin and CD23 observed in B-CLL? Although B-CLL lymphocytes do not recirculate as rapidly as normal peripheral blood lymphocytes, the greatly increased number of leukaemic cells in B-CLL ensures that much more soluble L-selectin and CD23 is generated during the recirculation of these cells through the body.
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Zarrouk, Marouan. "The role of ezrin/radixin/moesin(ERM) proteins in L-selectin-dependent signalling." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510756.
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Davies, Jessica Ellen. "Exploring the role of L-selectin shedding in regulating neutrophil polarity and chemotaxis." Thesis, King's College London (University of London), 2017. https://kclpure.kcl.ac.uk/portal/en/theses/exploring-the-role-of-lselectin-shedding-in-regulating-neutrophil-polarity-and-chemotaxis(1fb61cde-9323-4f79-a04b-7d312c2c7da8).html.
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Inflammation is a biological response to injury – a fundamental part of which involves the influx of leukocytes to the affected area. Circulating neutrophils are typically the first responders to an inflammatory insult. Orchestrated interactions between neutrophils and the underlying endothelium and occurs in a process termed the “multi-step leukocyte adhesion cascade”. L-selectin, a cell adhesion molecule, expressed on all circulating neutrophils, and facilitates the initial tethering and rolling events. Previously, L-selectin on CD14-positive (“inflammatory”) monocytes was shown to undergo ectodomain “shedding”, exclusively during transendothelial migration (TEM) and not before. The consequence of this was to establish monocyte polarity within the subendothelial space. The primary aim of this project was to determine if L-selectin shedding during TEM was exclusive to monocytes or extended to neutrophils. Perfusion of primary human neutrophils over activated endothelial monolayers revealed that L-selectin shedding was also activated specifically during TEM. Ectopic expression of L-selectin tagged to green fluorescent protein (GFP) in HL-60 cells (a neutrophil-like cell line that does not express endogenous L-selectin) significantly increased their invasive potential across activated endothelial cells under flow. Blocking L-selectin shedding (either pharmacologically in primary neutrophils or genetically in HL60 cells) promoted cell elongation in fully transmigrated cells, which significantly impacted cell polarity and directional persistence in 2D and 3D collagen scaffolds. Additionally, manufacturing bespoke microfluidic flow chamber devices revealed that blocking L-selectin shedding impacted the neutrophil chemotaxis towards classic “end-stage chemoattractants”, such as fMLP. Taken together, L-selectin shedding ensures that fully transmigrated neutrophils can establish front-back polarity so that they can home optimally to their inflamed targets. As fMLP is secreted during sterile injury, the potential therapeutic targeting of L-selectin shedding in the setting of myocardial infarction is discussed.
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Kumari, Shalini [Verfasser]. "Sulfated Multivalent Polymers for inhibition of L-selectin and LOX-1 Receptors / Shalini Kumari." Berlin : Freie Universität Berlin, 2019. http://d-nb.info/1178424499/34.
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Buscher, Konrad-Robert [Verfasser]. "Microvillus positioning of L-selectin and CD44 and its impact on leukocyte adhesion / Konrad-Robert Buscher." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2012. http://d-nb.info/1029847878/34.
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Nasu, Takaaki. "Studies on Function and Mechanism of Cell Adhesion Mediated by Carcinoembryonic Antigen (CEA) or L-selectin." Kyoto University, 2001. http://hdl.handle.net/2433/150790.
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Green, Paula. "Studies of combining specificities of endogenous lectins : mannose-6-phosphate receptor, L-selectin and mannan-binding protein." Thesis, Open University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333975.
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Cellars, Nicholas J. "α2,3 Sialylated Breast and Colon Cancer Cells and Extracellular Vesicles Bind to L-selectin Under Flow Conditions." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1588334308653355.
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Mohammed, Rebar N. "The impact of L-selectin/CD62L on the co-stimulation and migration of CD8+ T cells during virus infection." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/88514/.
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The strategy of the adaptive immune system in eliminating viruses from infected tissues is the activation of CD8+ T cells with specific T cell receptor in the LN draining the site of virus entry and subsequent migration of these cells to the sites of the viral infection. L-selectin, a well characterized LN homing receptor, is variably expressed on virus peptide activated CD8+ T cells, regulated through two separate mechanisms of early ectodomain shedding and late gene silencing. The role of L-selectin in homing of activated CD8+ T cells to sites of virus infection is not studies in detail. Here we show that despite being primed normally in the draining LN, there were a hierarchy in homing ability of adoptively transferred CD8+ T cells expressing mutant L-selectin(which resist shedding and gene silencing upon T cell activation), wildtype Lselectin and deficient in L-selectin (Ko) to the site of virus infection. The Lselectin specific recruitment was confirmed by using antibody blockade strategy and short-term competitive homing experiments. Furthermore, Lselectin dependent homing of virus specific CD8+ T cells rather than hyperfunctional or hyperproliferative T cells conferred anti-viral immunity against two evolutionarily distinct viruses, vaccinia and influenza viruses which infect mucosal and visceral organs, respectively.
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Sousa, Daniel Willian Lustosa de. "ExpressÃo da L-Selectina e do CD44 nas leucemias linfÃides agudas em crianÃas e dolescentes." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=8756.
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IntroduÃÃo â AlteraÃÃes na expressÃo ou funÃÃo das molÃculas de adesÃo (MA) nas cÃlulas leucÃmicas podem contribuir para a evoluÃÃo e no comportamento biolÃgico das leucemias agudas. A expressÃo aumentada nas LLAs parece relacionar-se aos mecanismos de disseminaÃÃo extramedular dos linfoblastos, infiltraÃÃo do SNC e formaÃÃo de massas tumorais. Objetivos â Analisar a expressÃo da L-selectina e do CD44 nas LLAs em crianÃas e adolescentes. Avaliar os fatores prognÃsticos (idade, sexo, leucometria ao diagnÃstico, imunofenÃtipo, classificaÃÃo FAB, EGIL, Ãndice de DNA e resposta ao tratamento de induÃÃo) e as apresentaÃÃes extramedulares das LLAs e correlacionÃ-los com essas MA. Pacientes e MÃtodos â Foram avaliados 76 pacientes com LLA, tratados com o Protocolo GBTLI-LLA. O diagnÃstico foi baseado em critÃrios FAB, imunofenotÃpicos (EGIL) e citogenÃticos. A expressÃo das MA foi avaliada por citometria de fluxo, utilizando tripla marcaÃÃo. O anticorpo monoclonal CD45-PerCP (ImmunotechÂ) foi utlizado como marcador dos linfoblastos. O CD44-PE (Clone HP2/9 - ImmunostepÂ) e o CD62L-FITC (Clone HI62L - ImmunostepÂ) foram utilizados para a marcaÃÃo das MA. Para a anÃlise das amostras e o cÃlculo da intensidade mÃdia de fluorescÃncia foi utilizado o programa Cell Quest. Na anÃlise estatÃstica utilizou-se o software SPSS 16.0. A associaÃÃo entre as variÃveis, os fatores prognÃsticos e resposta foi realizada com os testes de Qui-quadrado, exato de Fisher e Mann-Whitney. Sobrevida global foi determinada por curvas Kaplan-Meier e teste log-rank. AnÃlise multivariada por modelo proporcional de Cox foi utilizada para assegurar a independÃncia dos fatores prognÃsticos. Resultados â A mÃdia de idade foi 6,3Â0,5 anos (5m -17a) e predominou o sexo masculino (65%). Ao diagnÃstico os achados clÃnicos foram: hepatomegalia (63%), esplenomegalia (58%) e linfadenomegalia (44%). A infiltraÃÃo SNC ocorreu em 6,6% dos casos e o alargamento de mediastino em 11,8%. Quanto ao risco, 54% eram baixo risco e 46% alto risco. A classificaÃÃo FAB determinou 83% como L1 e 17% L2. DiagnÃstico de LLA-B foi mais frequente (89,5%) e o da LLA-T em 10,5% dos pacientes. O subtipo EGIL mais prevalente foi B II e B III, 51,5% e 45% respectivamente. O IDNA ≥ 1.16 foi encontrado em 19% dos pacientes e associou-se a bom prognÃstico. Na avaliaÃÃo do D8, 95% dos pacientes apresentaram contagem de blastos <1000/mm3 e leucÃcitos < 5.000/mm3. A taxa de remissÃo de induÃÃo foi de 95% e ocorreram 2,6% de Ãbitos na induÃÃo. Observou-se uma maior expressÃo do CD44 na LLA-T (87,5%/ IMF=150,44Â20,29), porÃm sem significÃncia estatÃstica. LLAs com massa tumoral apresentaram 84% de expressÃo do CD44, quando comparada a 52% das LLAs sem massa tumoral (p=0.01; OR=4,8). ExpressÃo aumentada da L-selectina na LLA-T (87,5%/IMF=272,33Â52,72) foi estatisticamente significante (p=0,004), comparado a LLA-B (54,5%/ IMF= 115,90Â12,75). NÃo houve correlaÃÃo entre os outros fatores prognÃsticos e essas MA. Na anÃlise multivariada as variÃveis de maior impacto para a sobrevida foram: a leucometria ao diagnÃstico, sexo, imunofenÃtipo T e a L-selectina. ConclusÃo â A expressÃo da L-selectina e do CD44 estÃo aumentadas nas LLAs estudadas, principalmente na LLA-T. O CD44 correlacionou-se com LLAs com massas tumorais e parece estar relacionado aos mecanismos de disseminaÃÃo extramedular dos linfoblastosIntroduction â Altered expression or function of adhesion molecules on leukemic blasts may contribute to the evolution of acute leukemia and its biological behavior. The elevated expression of adhesion molecules in ALL might be correlated with the extramedullary dissemination of blast cells, CNS involvement and leukemia tumor burden. Purpose â To analyze the expression of L-selectin and CD44 in ALL in children and adolescents. As well as to evaluate the prognostic factors (age, gender, initial leukocyte count, immunophenotype, FAB and EGIL classification, DNA index and early response to treatment) and the extramedullary presentation of ALL, to finally correlate the prognostic factors with these adhesion molecules. Patients and Methods â From November 2007 to November 2008, 76 patients with newly diagnosed ALL started on Brazilian GBTLI-ALL Protocol. The diagnosis was based on cytological, immunophenotypic, and cytogenetic methods. The mean fluorescence intensity (MFI) and the percentage of the adhesion molecules blasts cells was measured by flow cytometry using triple staining with McAb directly conjugated. CD45-PerCP positive cells were gated for blasts analysis. Anti-CD44-PE (Clone HP2/9 - ImmunostepÂ) and CD62L-FITC (Clone HI62L - ImmunostepÂ) were used to mark the adhesion molecules. The Cell Quest program was used for data acquisition and analysis. Statistical analysis was done by SPSS 16.0 Software. The association of features, prognosis and response to treatment was assessed by Chi-square, Fisher exact and Mann-Whitney tests. Overall survival curves were constructed by the Kaplan-Meier method and the log-rank test. Multivariate Cox regression analysis showed independent prognostic factors. Results â The mean age at diagnosis was 6.3Â0.5 years (range 9mo to 17yr) and 65% of them were boys. Clinical findings were hepatomegaly (63%), splenomegaly (58%), lymphadenopathy (44%). CNS involvement was detected in 6.6% of cases and mediastinal mass appeared in 11.8% of them. Patients were classified into low risk (54%) and high risk (46%). FAB classification identified 83% as L1 and 17% as L2. Immunophenotypically, 89.5% of patients were classified as B-lineage ALL and 10.5% as T-lineage ALL. The most frequent EGIL subtype was B common and pre-B-ALL (51.5% and 45.5%, respectively). DNA index greater than 1.16 was found in 19% of the patients and was associated with favorable prognosis. On the D8 evaluation, 95% of the patients had blast count lower than 1.000/mm3 and leukocyte count lower than 5.000/mm3. The remission induction rate was 95% and there was a rate of 2.6% of death during induction therapy. CD44 had greater expression to the rate of 87.5% in T-cell ALL (MFI=150.44Â20.29) with no statistical correlation. A significant positive correlation was demonstrated between 84% of CD44 expression and Leukemia burden tumor cases (p=0.01; OR=4.8). There was statistical correlation between L-selectin expression (87.5%/MFI=272.33Â52.72) and T-cell ALL (p=0,004). No significant correlation was detected between L-selectin and CD44 expression and other prognostic factors. Multivariate statistical analysis (adjusted for overall survival) indicated that initial leukocyte count, gender, T immunophenotype and L-selectin were independent factors. Conclusion â L-selectin and CD44 expressions were elevated in ALL studied, mainly in T-cell ALL. The research demonstrated that there is an association between CD44 expression and leukemia tumor burden, which might be involved in the dissemination of leukemic cells and the progression of the disease.
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Gratopp, Alexander. "Messung L-Selektin-abhängiger Adhäsionsprozesse mit Hilfe eines homotypischen Aggregationsassays." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2000. http://dx.doi.org/10.18452/14489.
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Ischemia followed by reperfusion, as happens in myocardial infarction, or the development of acute respiratory distress syndrome, are associated with a exaggerated extravasation of leukocytes into the surrounding tissue , which may cause severe bystander damage. In animal models of these diseases, pharmacological blockage of the leukocyte adhesion molecule, L-selectin (CD62L), has been shown to be partially protective by reduction or inhibition of leukocyte-mediated secondary tissue damage. The aim of this project was the development of an in vitro assay to investigate the relative effectiveness of potential L-selectin antagonists. Ideally, the assay should require low sample volumes and allow for measurements of larger series of reagents. The assay system investigated was based on the homotypic granulocyte aggregation under shear stress, which mimicks the L-selectin-dependent adhesion of leukocytes to previously arrested neutrophils on vascular endothelium. After optimizing numerous variables of the aggregation assay, the requirement of L-selectin for the homotypic granulocyte aggregation induced was demonstrated by inhibition experiments using soluble L-selectin or monoclonal antibodies directed against the lectin domain of L-selectin. Several carbohydrate polymers with L-selectin binding properties, such as the seaweed-derived fucose polymer fucoidin, high-molecular-weight dextran sulfate or heparin, also inhibited neutrophil aggregation in a dose-dependent fashion. However, despite employing a flow cytometry-based read-out technique, the assay remained extremely labor intensive, precluding investigations of extended series. Therefore, the homotypic aggregation experiments with freshly isolated human granulocytes remains a useful tool to further evaluate specific questions of L-selectin dependent adhesion processes, but it is not apt for transfer into routine laboratories.
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Fultz, Caroline Brigitte. "Differential Expression of Homing-Associated Cell Adhesion Molecule, Very Late Antigen-4 and L-Selectin in Hematopoietic Progenitor Cell Trafficking between the Marrow and Blood." Scholar Commons, 1998. http://scholarcommons.usf.edu/etd/4427.
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This study addresses the hypothesis that the following cell adhesion molecules (CAMs): homing-associated cell adhesion molecule (HCAM), very late antigen-4 (VLA-4) and L-selecti I I . . n p ay a ro e m the trafficking of hematopoietic progenitor cells (HPCs) between the bone marrow microenvironment and the peripheral circulation. In order to ascertain differences in CAM expression based on physiologic compartment, the expression of HCAM, VLA-4 or L-selectin per CD34+ myeloid progenitor cell was assessed between paired samples of blood and marrow. CAM expression was flow cytometrically quantitated in paired samples obtained from patients treated with cell than those in circulation. To functionally demonstrate the hematopoietic potential of mobilizing doses of granulocyte-colony stimulating factor (G-CSF) or from normal donors donating for allogeneic transplant. In G-CSF mobilized patients, marrow derived CD34+ myeloid progenitor cells expressed more VLA-4 per cell than those in circulation. In normal donors, marrow derived myeloid progenitor cells expressed more CD34 per CAM expressing (HCAM+, VLA-4+ or L-selectin+) CD34+ myeloid progenitors, colony forming unit (CFU) and long term culture initiating cell (LTCIC) assays of flow cytometrically sorted normal marrow and blood CAM+!-CD34+myeloid progenitors were performed. L-selectin+CD34+ myeloid progenitors formed a greater percentage of BFU-E colonies and a lower percentage of CFU-GM colonies than all other CAM+!- CD34+ myeloid progenitors sorted from norma I bl00d. In normal donors, CAM+!-CD34+ myeloid. progerut.ors sorte d from blood formed significantly more colonies per 10· plated cells than those denv.ed from marrow. L-selectin+CD34+ myeloid progenitors derived . d . .fi antly more L TCIC (per 10· sorted CAM+CD34+myeloid from marrow contame srgni IC x progenitors) than those expressing RCAM or VLA-4. In order to determine whether CD34+ myeloid progenitors utilize VLA-4 to bind to fibronectin (FN), in vitro binding assays were performed Adhesion of normal blood derived VLA-4+ CD34+ myeloid progenitors to FN was blocked by the addition of monoclonal antibodies against the a4 subunit of VLA-4. These data suggest a model ofHPC trafficking, in which HPCs utilize VLA-4 to adhere to components of the bone marrow microenvironment, while HPe modulation of L-selectin affinity plays an important role in HPC homing and a less direct role in hematopoietic reconstitution.
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Thanabalasingam, Usan. "Flussgeschwindigkeiten von Leukozyten über Endothelzellmonolayer." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2004. http://dx.doi.org/10.18452/15093.
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Das Ziel dieser Arbeit war die Untersuchung der Rollgeschwindigkeiten von Leukozyten auf humanen kardialen mikrovaskulären Endothelzellen (HCMEC) und humanen umbilikalen venösen Endothelzellen (HUVEC). Die Endothelzellen wurden aus explantierten humanen Herzen sowie aus menschlichen Nabelschnüren unmittelbar postpartal gewonnen. Unter definierten Bedingungen wurden die in einer Flusskammer gemessenen Geschwindigkeiten von L-Selektin exprimierenden Nalm6-IF4 Zellen auf unstimulierten Endothelzellen mit denen auf stimulierten Endothelzellen verglichen. Die langsamere Geschwindigkeit der Leukozyten auf stimulierten Endothelzellen weist darauf hin, dass L-Selektin Liganden auf humanen kardialen mikrovaskulären Endothelzellen erst nach Stimulation exprimiert werden. Die beobachtete Geschwindigkeitsreduktion der Leukozyten ist jedoch von dem in der Literatur beschriebenen Selektin vermittelten Rollen zu unterscheiden. In den Versuchen mit Tunicamycin wurde gezeigt, dass N-glykosidisch gebundene Zucker kritische Bestandteile der Liganden für ihre Interaktion mit L-Selektin sind. Unter den gleichen Versuchsbedingungen wurde auch der Einfluss E-Selektin vermittelter Interaktionen auf die Geschwindigkeit der HL60 Zellen untersucht. Neben dem typischen Rollen wurde hier ebenfalls eine Selektin abhängige Geschwindigkeitsreduktion gesehen.The aim of the present study was to investigate selectin mediated rolling velocities of leucocytes on human cardiac microvascular endothelial cells (HCMEC) and human umbilical vein endothelial cells (HUVEC). HCMEC were gained from explanted human hearts and HUVEC from umbilical cords immediately postpartum. Flow velocities of L-Selectin expressing Nalm6-IF4 cells on quiesent endothelial cells were compared to those on stimulated endothelial cells. Stimulation of endothelial cells with TNF led to significantly slower velocities of Nalm6-IF4 cells indicating that HCMEC express L-Selectin ligands only after stimulation. The observed reduction of flow velocities differs from rolling of leucocytes described in the literature. Experiments with tunicamycin showed that N-glycosylated carbohydtrate moieties are needed for proper function of L-Selectin ligands. E-Selectin mediated interactions between HL60 cells and endothelial cells were studied under the same conditions. Besides the typical rolling, a selectin mediated reduction of flow velocity was observed.
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Lejtenyi, Duncan. "Natural killer cells and B lymphocytes in L-selectin and CD18 knock out mice : marker-dependent but not lineage-dependent changes in the spleen and bone marrow." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81355.
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Lymphocyte homing to the lymph nodes is a well defined process, dependent on the proper function of the homing receptors LFA-1 (one of the CD18 family of integrins) and L-selectin. However, the mechanism used by lymphocytes to accumulate in the spleen is still not understood. Both B lymphocytes and Natural Killer cells are prominent in the spleen. To investigate whether CD18 integrins or L-selectin play a role in B lymphocyte and NK cell homing to the spleen, mice genetically deficient in either of these molecules were analyzed by flow cytometry. The results of this study demonstrate that neither B lymphocytes nor NK cells require the CD18 family of integrins or L-selectin for entry into the spleen. Results of this study also showed that neither cell lineage required the CD18 integrins or L-selectin for egress from their sites of birth in the bone marrow.
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Höhn, Thomas. "Effekte von Hyperoxie und Stickstoffmonoxid beim Neugeborenen." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2002. http://dx.doi.org/10.18452/13827.
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In der vorliegenden Arbeit sind Untersuchungen vorgestellt, die sich mit Wirkungen und Interaktionen von zwei ubiquitär im menschlichen Körper vorkommenden Gasen befassen, i.e. Sauerstoff und Stickstoffmonoxid. Im Falle beider Substanzen ermöglicht die geringe Größe der Moleküle eine freie Diffusion über Membranen hinweg, eine Eigenschaft, die für die Funktion der Signaltransduktion geradezu prädestiniert. Aus den vorgelegten Untersuchungen lassen sich die folgenden Folgerungen ableiten: * Stickstoffmonoxid wirkt in-vitro selektiv bakteriostatisch auf Bakterien, die üblicherweise Früh- und Neugeborene besiedeln. Dabei hängt die Selektivität von den jeweiligen bakteriellen Verteidigungsmechanismen ab, die bakteriostatische Wirkung liegt in einem Konzentrationsbereich, der außerhalb desjenigen liegt, der derzeit klinisch angewendet wird. * Hyperoxie führt im Ganztiermodell der unreifen Ratte zu einer zerebralen Hochregulation von iNOS und damit zur Synthese von NO. Soweit dies anhand der Synthese von Peroxynitrit als definitivem Schädigungsmechanismus beurteilbar ist, wird trotz entsprechender iNOS-Expression wenig bis gar kein Peroxynitrit gebildet. Da das Zusammentreffen von NO und Sauerstoff sonst regelhaft zur Entstehung von Peroxynitrit führt, müssen im Gehirn der unreifen Ratte ausreichende antioxidative Schutzmechanismen präsent sein, die diese Reaktion verhindern. * Im in-vitro-Modell der Gasäquilibrierung von Nabelschnur-PMN zeigte sich unter Hyperoxie das ausgeprägteste Aktivierungsmuster aller verglichenen Sauerstoffkonzentrationen. Dies stand im Gegensatz zur Exposition adulter Zellen, hier fand sich eine größere Hyperoxietoleranz bei gleichzeitig stärkster Aktivierung unter Hypoxiebedingungen. Welche Bedeutung diesen Ergebnissen im klinischen Umgang mit Neugeborenen zukommt muß derzeit noch offen bleiben. Allerdings häufen sich Hinweise aus experimentellen Studien, die darauf hindeuten, daß ein restriktiver Umgang mit hohen Sauerstoffkonzentrationen auch im klinischen Umfeld gerechtfertigt sein könnte.The present investigations deal with the effects and interactions of gases, which are ubiquitous in the human body i.e. oxygen and nitric oxide. Both substances are small enough to freely diffuse across biological membranes. This ability predestines both molecules for the function of signal transduction. The results of our investigations lead to conclusions as follows: * Nitric oxide has selective bacteriostatic effects in-vitro on some bacterial strains typically isolated from preterm and term newborn infants. Selectivity depends on the presence of bacterial defense mechanisms. The bacteriostatic effect takes place at concentrations above those currently used in clinical practice. * Hyperoxia leads to upregulation of iNOS and subsequent NO production in an animal model of the immature rat. Despite this upregulation of iNOS synthesis there is no increased production of peroxynitrite which is known to cause cellular and DNA damage. Since the combination of NO and high concentrations of oxygen lead to peroxynitrite formation on a regular basis, effective antioxidant mechanisms appear to prevent peroxynitrite formation in the brain of the immature rat. * The most pronounced activation of cord blood polymorphonuclear cells (PMN) during conditions of hyperoxia, normoxia, and hypoxia was found for exposure towards high oxygen concentrations in an in-vitro model of gas equilibration. As opposed to that, hypoxia was the most potent trigger for adult PMN. It remains to be determined which clinical implications must be derived from these results. However, increasing experimental evidence indicates that exposure towards high oxygen concentrations should be restricted also in clinical practice and not only in preterm infants, but also in term newborns.
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Adhikari, Shishir Raj. "STATISTICAL PHYSICS OF CELL ADHESION COMPLEXES AND MACHINE LEARNING." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1562167640484477.
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Delaere, Ian. "The chemistry of Vivia sativa L. selection." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phd332.pdf.
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Bibliography: leaves 151-166. This thesis describes the development of two novel and complementary analytical approaches for assaying cyanoalanine non-protein amino acids. These assays are used to determine the distribution of these compounds both within and between plants and to identify accessions of common vetch which contain low levels of the cyanoalanine non-protein amino acids in germplasm collections. These analytical tools are used to correlate toxicity observed in animal feeding experiments with the cyanoalanine content. This thesis covers also the first report of the use of diffuse reflectance using dispersive infrared spectrometry for the "in situ" quantification of specific organic components from plant tissue as well as the first use of micellar electrokinetic chromatography for the quantitative analysis of 9-fluorenylmethyl chloroformate (FMOC) derivatised and non-derivatised components of extracts from plant material.
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Watt, Jon. "Prey selection by coastal otters (Lutra lutra L.)." Thesis, University of Aberdeen, 1991. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=128373.
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The thesis investigated the proximate factors affecting selection among different prey types by coastal otters. From a broad description of coastal otter diet, and its relationship to prey availability, the work progressed to a detailed study of the predatory behaviour of individuals and age classes, and thence to the formulation and testing of specific hypotheses regarding prey choice. Spraint analysis showed that the diet of otters in Loch Spelve consisted principally of small, demersal inshore fishes and shore crabs. It was demonstrated that while the frequency of occurrence of most fish species in spraints seemed to reflect availability, the occurrence of shore crabs did not. Direct observations of foraging otters showed that there were large differences in prey selection and foraging behaviour between age classes of otter. In particular shore crabs were consumed almost exclusively by juvenile otters and rarely appeared in the diets of adults. Foraging efficiency was shown to improve gradually with age and experience, and as it did so the proportion of shore crab in the diet decreased. It was surmised that shore crabs were not a preferred prey, but were relatively easy for juvenile otters to locate and capture. It was hypothesised that the apparent preferences of otters for certain prey types, such as for fish over shore crabs, were based on the relative energetic profitabilities of those prey types. A detailed examination of the costs and benefits, in terms of time and energy respectively, to otters of feeding on the main prey species supported this hypothesis. Shore crabs were markedly unprofitable, requiring considerable time expenditure for relatively little energy return. An apparent preference for rocklings and eelpout over butterfish was also consistent with the relative profitabilities of these species.
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Arias, Iliana Corría. "Selection of new eggplant (Solanum melongena, L.) lines." Doctoral thesis, Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 2011. http://dx.doi.org/10.18452/16377.
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In den letzten Jahren ist das Interesse der Europäer am Verbrauch „Exotischer Gemüsearten“ gewachsen wie z.B. für asiatische Auberginengenotypen, die sich in der Farbe, im Geschmack und der Form von den standardmäßigen dunklen violetten Auberginenfrüchten unterscheiden. Diese Entwicklung kann die Einführung und die Kommerzialisierung neuer asiatischer Auberginensorten in Westeuropa beeinflussen und dadurch die Vielfalt des Angebots mit diesem Gemüse in den gemäßigten Regionen erhöhen. Aus diesem Grund bestand das Ziel dieser Arbeit darin, einige asiatische Genotypen (hauptsächlich vietnamesischen Ursprung) hinsichtlich ihres Wachstums und Ertrags zu untersuchen und diese mit typischen „europäischen“ Sorten bei einer Kultivierung im Gewächshaus zu vergleichen. Außerdem sollte geprüft werden, ob die genetische Variabilität von Samenherkünften verwendet werden könnte, um Klone zu selektieren, die den Wachstumsbedingungen in den Gewächshäusern unter den Klimabedingungen in Deutschland angepasst sind. In den in vitro Experimenten ist die Reaktion von 5 Auberginengenotypen auf die Mikrovermehrung und auf die in vitro Verfahren ausgewertet worden. Zusätzlich wurden die Einflüsse von Wachstumsregulatoren, NAA und 2.4D, auf die Kallus- und Organbildung und indirekte Pflanzenregeneration in vitro untersucht, um Aussagen hinsichtlich der Nutzbarkeit von biotechnologischen Züchtungsmethoden, zu erhalten. Das in vitro Klonen wurde mit dem Ziel durchgeführt, Klone von ausgewählten 5 asiatischen Auberginengenotypen zu erhalten, um Aussagen zu ihrer vegetativen und generativen Entwicklung sowie dem Ertrag zu erhalten, und mit typischen „europäischen“ Sorten unter Gewächshausbedingungen zu vergleichen. Alle Genotypen wurden einer der hydroponischen Substratkultur im Gewächshaus kultiviert. Die Entwicklung der Genotypen in organischen und mineralischen Substrat wurde verglichen. Das organische Substrat hat zum besseren Wachstum aller Auberginengenotypen geführt. Die aus der in vitro Vermehrung erhaltenen Klone der asiatischen Auberginengenotypen entwickelten sich zu normalen Pflanzen, die einen typischen Habitus erreichten und teilweise einen Ertrag hatten, der mit dem der Kontrolle vergleichbar war. Die besten asiatischen Auberginenklone hatten ähnliche Ergebnisse wie die der Kontrolle sowohl im Stadium des Blühbeginns, als auch im Ertrag. Ein wichtiges Merkmal für die Auswahl einiger asiatischer Klone war ihre Fähigkeit frühzeitig zu blühen, vergleichbar mit den „europäischen“ Sorten. Die asiatischen Genotypen waren charakterisiert durch schmalere und leichtere Früchte mit einem guten Geschmack, weniger Samen und einer guten Konsistenz des Fruchtfleisches im Vergleich mit den „europäischen“ Sorten. Ausgehend von den Ergebnissen die in den Untersuchungen erzielt wurden, scheint es möglich, neue stabile Genotypen zu erhalten, die geeignet sind für eine Kultivierung in der „Substratkultur“ im Gewächshäusern und die ein Potenzial für den Erwerbsanbau unter europäischen Bedingungen haben. Für eine Optimierung der Wachstumsbedingungen, insbesondere das Formierungssystem, sind weitere Forschungsarbeiten erforderlich zumal diese Genotypen sehr starkwüchsig sind. Des Weiteren sollte der optimale Erntezeitpunkt und die Fruchtqualität untersucht werden.Recently, there has been a growing interest of the Europeans in the consumption of „exotic vegetables“ like those of Asian eggplant genotypes different in colour, taste and shape from the traditional dark violet eggplant fruits. This may influence the introduction and commercialisation of Asian eggplant types in Western Europe, which will contribute to increase the biodiversity of this crop in temperate regions. Therefore, this work aimed at screening 4 Asian eggplant genotypes (mainly of Vietnamese origin) concerning their growth and yield in greenhouses in comparison to „European“ breeds. Moreover, it should be tested whether the genetic variability of seed progenies could be used to select plants adapted to the growing conditions in greenhouses under the climatic peculiarities in Germany. In in-vitro experiments the response of 5 selected eggplant genotypes to micropropagation and in-vitro manipulation has been evaluated. Further on the influence of plant growth regulators, e.g. NAA and 2,4 D, on the callus and organ formation, and indirect plant regeneration in-vitro were studied in preparation of use of biotechnological breeding methods later on. The in-vitro cloning was carried out with the aim to produce clones of 5 Asian eggplant genotypes to evaluate their vegetative and generative development, as well as the yield, in comparison with typical „European“ varieties under greenhouse conditions. All genotypes were cultivated in „substrate culture“ with drip irrigation. The influence of organic and mineral substrates on the growth and development of the eggplant genotypes was compared. The organic substrate favoured better growth of all eggplant genotypes. The in-vitro derived clones of Asian eggplant genotypes developed to normal plants that reached full maturity and some of them had a yield comparable with that of the controls, the typical „European“ varieties. The best Asian eggplant clones gave similar results as the controls in the beginning of flowering and the yield. The early flowering feature characteristic of some clones of Asian origin comparable to that of the typical „European“ varieties is very important for selection. Asian genotypes were characterized by smaller and lighter fruits having good taste, less seeds and good consistency in comparison with the „European“ varieties used as control. Derived from the results obtained in this research, it seems possible to obtain new stable genotypes for „substrate culture“ system in greenhouse with a potential for commercial production under European conditions. The optimization of growing conditions especially the pruning system needs further research for these very vigorously growing plant types. Further on studies regarding optimal harvesting time and fruit quality shall be done.
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Ushan, Wardah. "Portfolio selection using Random Matrix theory and L-Moments." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/16921.
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Includes bibliographical referencesMarkowitz's (1952) seminal work on Modern Portfolio Theory (MPT) describes a methodology to construct an optimal portfolio of risky stocks. The constructed portfolio is based on a trade-off between risk and reward, and will depend on the risk- return preferences of the investor. Implementation of MPT requires estimation of the expected returns and variances of each of the stocks, and the associated covariances between them. Historically, the sample mean vector and variance-covariance matrix have been used for this purpose. However, estimation errors result in the optimised portfolios performing poorly out-of-sample. This dissertation considers two approaches to obtaining a more robust estimate of the variance-covariance matrix. The first is Random Matrix Theory (RMT), which compares the eigenvalues of an empirical correlation matrix to those generated from a correlation matrix of purely random returns. Eigenvalues of the random correlation matrix follow the Marcenko-Pastur density, and lie within an upper and lower bound. This range is referred to as the "noise band". Eigenvalues of the empirical correlation matrix falling within the "noise band" are considered to provide no useful information. Thus, RMT proposes that they be filtered out to obtain a cleaned, robust estimate of the correlation and covariance matrices. The second approach uses L-moments, rather than conventional sample moments, to estimate the covariance and correlation matrices. L-moment estimates are more robust to outliers than conventional sample moments, in particular, when sample sizes are small. We use L-moments in conjunction with Random Matrix Theory to construct the minimum variance portfolio. In particular, we consider four strategies corresponding to the four different estimates of the covariance matrix: the L-moments estimate and sample moments estimate, each with and without the incorporation of RMT. We then analyse the performance of each of these strategies in terms of their risk-return characteristics, their performance and their diversification.
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Dias, Ana Carla da Silva Carvalho. "Efeito protetor da fucoidina, um inibidor de P e L-selectina, na resposta inflamatória sistêmica e distúrbios de motilidade gastrintestinal na pancreatite aguda experimental." reponame:Repositório Institucional da UFC, 2013. http://www.repositorio.ufc.br/handle/riufc/15730.
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DIAS, Ana Carla da Silva Carvalho. Efeito protetor da fucoidina, um inibidor de P e L-selectina, na resposta inflamatória sistêmica e distúrbios de motilidade gastrintestinal na pancreatite aguda experimental. 2013. 124 f. Tese (Doutorado em Farmacologia) – Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, 2013.Submitted by denise santos (denise.santos@ufc.br) on 2016-03-22T16:22:37Z No. of bitstreams: 1 2013_tese_acscdias.pdf: 6391660 bytes, checksum: 62b1f07c8aab044de5338353f4857e96 (MD5)
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Background & Aims: Neutrophils play a critical role in severe acute pancreatitis. Tissue infiltration of neutrophils in the pancreas is a multistep process, coordinated by specific adhesion molecules, such as P-selectin. Fucoidin is a sulphated fucosylated polysaccharide that binds to and blocks the function of L- and P-selectins, and the present study has evaluated whether fucoidin treatment could prevent neutrophil infiltration, and thereby reverse the systemic inflammation and gastrointestinal dysmotility associated with severe acute pancreatitis. Methods: Acute pancreatitis was induced in Swiss mice either by the retrograde infusion of taurolithocholic acid (3.0%) (TLC-S) into the pancreatic duct or by intraperitoneal injections of cerulein (50 µg/kg/h). The experimental groups received fucoidan (25 mg/kg, i.v.) before pancreatitis induction whist control groups received only saline. After 24 hours, pancreatic malondialdehyde (MDA), serum amylase, lipase, IL-1β, TNF- and nitrite were measured. In addition, myeloperoxidase (MPO) activity (lung, pancreas, stomach and jejunum) and histological assessment (pancreas) were determined. Gastric emptying and gastrointestinal transit (using the geometric center method) were also measured. Gastrointestinal contractility in vitro was recorded through force transducers coupled to a computerized data acquisition system, carbachol (0,01 µM – 30 µM), KCl 60mM and electrical field stimulation (0.5-8.0 Hz; 1ms; 40 V), was applied on gastric fundus and jejunum of mice 24 hours after TLC-S induced pancreatitis. Results: Pancreatic MDA, serum amylase, lipase, nitrite, TNF- and IL-1β, pancreatic and lung MPO, were increased in both TLCS- and cerulein acute pancreatitis compared with respective control groups. Fucoidan significantly decreased the augmented levels of amylase, lipase, pancreatic and lung MPO, MDA, TNF-, IL-1β and nitrite in both acute pancreatitis models. Pancreas histological changes observed in both models were significantly attenuated by fucoidan. The acute pancreatitis model induced by TLC-S caused delayed gastric emptying and gastrointestinal transit, incresead gastric and jejunum MPO, and jejunum hypercontractility in vitro. Fucoidan significantly reversed the gastrointestinal disorders in vivo and in vitro and augmented levels of gastric and jejunum MPO induced by TLC-S. Conclusion: Fucoidan reduced the severity of acute pancreatitis in mice by decreasing neutrophil infiltration, systemic inflammation and gastrointestinal dysmotility, suggesting that modulation of selectins may constitute a promising therapeutic approach for acute pancreatitis.
Introdução e objetivos: Os neutrófilos desempenham importante papel na pancreatite aguda grave. Infiltração de neutrófilos no pâncreas é um processo complexo, coordenado por moléculas de adesão específicas, tais como a P-selectina. Fucoidina é um polissacarídeo sulfatado que bloqueia a função da L-e P-selectinas. No presente estudo avaliamos se o tratamento com fucoidina poderia impedir a infiltração de neutrófilos e, assim, reverter a inflamação sistêmica e dismotilidades gastrintestinais associadas à pancreatite aguda grave. Métodos: A pancreatite aguda foi induzida em camundongos Swiss pela infusão retrógrada de ácido taurolitocólico (3,0%) (TLC-S) no ducto pancreático ou por injeções intraperitoneais de ceruleína (50 µg/kg/h). Os grupos experimentais receberam fucoidina (25 mg/kg, iv) antes da indução da pancreatite, e os grupos de controle receberam apenas solução salina. Após 24 horas, os níveis séricos de amilase, lipase, IL-1β, TNF-α, nitrito e de malondialdeído (MDA) pancreático foram medidos. Além disso, a atividade de mieloperoxidase (MPO) (pulmão, pâncreas, estômago e jejuno) e avaliação histológica (pâncreas) foram determinadas. O esvaziamento gástrico e trânsito gastrintestinal foram medidos pelo método de centro geométrico. A contratilidade gastrintestinal in vitro foi registrada através de transdutores de força conectados a sistema computadorizado de aquisição de dados. Carbacol (0,01 µM - 30 µM), KCl 60 mM e estimulação eléctrica (0,5-8,0 Hz; 1ms, 40 V), foram aplicados sobre o fundo gástrico e jejuno dos animais 24 horas após a pancreatite induzida por TLC-S. Resultados: Os níveis de MDA pancreático, amilase, lipase, nitrito, TNF-α e IL-1β séricos, bem como MPO pancreática e pulmonar estavam aumentados tanto no modelo de pancreatite aguda induzida por TLCS quanto no modelo ceruleína quando comparado aos grupos controle correspondentes. Fucoidina reduziu significativamente os níveis aumentados de amilase, lipase, MPO pancreática e pulmonar, MDA, TNF-α, IL-1β e nitrito em ambos os modelos de pancreatite aguda. As mudanças histológicas observadas no pâncreas em ambos os modelos foram significativamente atenuadas pela fucoidina. O modelo de pancreatite aguda induzida por TLC-S induziu retardo no esvaziamento gástrico e trânsito gastrointestinal, aumento de MPO no estômago e no jejuno, além de hipercontratilidade de jejuno in vitro. Fucoidina reverteu significativamente os distúrbios gastrintestinais in vivo e in vitro e os níveis aumentados de MPO gástrica e jejunal induzidos pela injeção de TLC-S. Conclusão: Fucoidina reduziu a gravidade da pancreatite aguda experimental através da diminuição da infiltração de neutrófilos, inflamação sistêmica e dismotilidades gastrintestinais, sugerindo que a modulação das selectinas, pode constituir uma abordagem terapêutica promissora para pancreatite aguda.
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Tousignant, Denise. "Selection response to global change of Brassica juncea (L.) czern." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69693.
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The potential for an adaptive response to global climatic change was evaluated for an annual C$ sb3$ weed, Brassica juncea, by performing a selection on fecundity for eight generations. During the selection, atmospheric carbon dioxide and temperature were gradually increased from current levels (370 $ rm mu L cdot L sp{-1}$ CO$ sb2$, 20$ sp circ$C) to conditions predicted during the next century by climate models (650 $ rm mu L cdot L sp{-1}$ CO$ sb2$, 23.6$ sp circ$C) including heat stress events at 32$ sp circ$C/26$ sp circ$C day/night), At the end of the selection, a reciprocal transplant experiment was conducted to identify genetic differences between control selection lines of plants and those selected under increasing CO$ sb2$ and temperature. I observed a genetic adaptation of early vegetative growth elevated CO$ sb2$ and temperature, which resulted in to 63% more biomass and 11% higher photosynthetic rates. Reproductive biomass, however, was decreased during the selection, mainly due to temperature stress, which disrupted flower development and induced strong maternal effects, counteracting the selection on fecundity.
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Swanson, Meredith. "Cornus Mas L. Cultivar Selection Based on Hardiness and Propagation." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/31530.
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Cornus mas (Cornelian cherry) is a deciduous shrub/small tree native to southeastern Europe and western Asia. It is unique among the Cornaceae (dogwood) family in that the fruit is used for human consumption and is highly nutritious and contains high amounts of antioxidants and anthocyanins. While this plant has many desirable fruiting and ornamental characteristics, it has seen limited use in North America. Several of these desirable characteristics are low disease and pest incidence, fruit qualities, and early yet long-lasting flowers. With limited use in North America, hardiness speculations are based on only a few individual plants. In this document, artificial freeze tests were conducted to better understand hardiness of the species and how vulnerable plants are when coming out of dormancy in the spring. Propagation methods (micropropagation, in vitro and ex vitro rooting of plantlets, and grafting) were also evaluated to determine the optimal method of growing cultivars.
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Mascaro, Maite. "Crab foraging behaviour : prey size and species selection in Carcinus maenas (L.) and Cancer pagurus L." Thesis, Bangor University, 1998. https://research.bangor.ac.uk/portal/en/theses/crab-foraging-behaviour--prey-size-and-species-selection-in-carcinus-maenas-l-and-cancer-pagurus-l(402c594d-fe2f-42be-a39e-349cf07afff2).html.
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This thesis examines the foraging behaviour of Carcinus maenas and Cancerpagurus when presented with bivalves of contrasting morphology: Mytilus edulis, Ostrea edulis, Crassostrea gigas and Cerastoderma edule. Because foraging may be influenced by the relative abundance and morphological characteristics of both predator and prey, these aspects are also considered. Chelal size and strength of these crabs and prey shell shape largely determined handling techniques. When offered a size range of these bivalves individually, crabs attacked all encountered prey but rejected those that remained unbroken after several opening attempts, thus, emphasising the passive nature of their size-selective feeding. When offered paired combinations of mussels, oysters and cockles, larger crabs selected species in the ranked order of their profitability. Species-related preferences exhibited by crabs feeding on prey at or near the optimal size suggest that foraging decisions are partly based on evaluations of overall prey shape and volume, and that shell width constitutes an important feature which crabs recognise and associate with prey value. Variations in crab strength relative to size accounted for most intra-specific differences in foraging behaviour. Juvenile C maenas are limited in their choice of prey size, and are thus less species-selective. Adult C maenas are not so constrained, and exhibit a higher degree of species-selectivity. C. pagurus possesses powerful monomorphic chelae that operate at higher mechanical advantage than the cbelae of C maenas, and readily crushed larger mussels relative to their size. Differences in prey size selection between crab species varied with the species of prey offered, suggesting that certain shell features of these bivalves constitute effective barriers to even the powerful chelae of C pagurus. These results are relevant in the context of aquaculture, since predatory impact on commercially reared bivalves might be reduced by combining different prey species that offer predators alternative or preferred sources of food.
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Masawe, Peter A. L. "Aspects of breeding and selecting improved cashew genotypes (Anacardium occidentale L.)." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386973.
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Dodd, Jane. "Topographic learning and memory in habitat selection by Lipophrys pholis L." Thesis, Bangor University, 1998. https://research.bangor.ac.uk/portal/en/theses/topographic-learning-and-memory-in-habitat-selection-by-lipophrys-pholis-l(65cf5889-e075-4b3b-a268-06e3484ce380).html.
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Experiments were carried out to test the ability of L. pholis to learn and remember the position of a food reward in a hierarchical maze during daily trials. This task was completed in 9 days in the presence of LegoTM landmarks. Learning did not take place in the presence of a white screen clue or in the absence of any obvious visual clues after 15 days. An attempt was made to identify the effect of a change in conditions on L. pholis who had already learned to successfully navigate the hierarchical maze, and to identify the clues utilised in learning, by altering the intra and extramaze clues. Geomagnetic, olfactory / gustatory and current direction clues were eliminated as the source of spatial information, as was the use of a cognitive map (Tolman 1948, O'Keefe & Nadel 1978). Rather, evidence suggested that the fish were learning a specific route through the hierarchical maze using the LegoTM towers as beacons, and as a prompt as to which direction to turn at important stages in the journey. This memory was retained for a period of at least 30 days. A hierarchy of clue use was suggested by the fact that the subjects used the direction of entry to the experimental arena, or the direction by which the experimenter left the arena just prior to a daily test, as a directional clue to the position of the reward box in the absence of Lego towers. These experiments suggested that in the wild L. pholis uses the position of local landmarks, such as rocks and clumps of algae, to direct movements towards feeding patches. A study of behaviour of L. pholis placed in a novel artificial habitat was also carried out. L. pholis moved along the edges of the objects placed in the arena, followed regularly used paths between refuges, and explored the arena from a series of "base" refuges. In the more active individuals, each refuge was investigated until the subject took up residence in a preferred refuge. This adopted shelter was often centrally placed and commanded a good view of a large area of the arena. Activity was concentrated in the more complex half of the arena and experienced fish directed their movement towards this area 24 hours after 6 hours exploration of the novel habitat. There was also evidence to suggest that certain individuals learned the position of a specific preferred refuge after the 6 hour exploratory period. Finally, the ability of L. pholis to remember the position of a refuge was tested in an artificial habitat under the influence of different clues. L. pholis learned the position of the refuge in the presence of an A4 sized black screen clue only. They responded to this clue by moving towards it and pressing themselves up against it while LegoTM towers and a white screen clue did not provoke such a response. L. pholis continued to respond to the black screen in this way even when it was moved to another location further from the refuge. After 12 days L. pholis learned to use the black screen as an indirect clue and navigate to the refuge directly without first touching it. These results suggested that when placed in a novel habitat the immediate reaction of L. pholis is to move quickly towards the first dark area they see. Later, they systematically explore all available shelters and choose a preferred one according to complexity of the surrounding habitat. With experience, they can use the position of objects around them to navigate quickly and efficiently to their preferred refuge or the nearest suitable refuge depending on the severity of the threat.
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Brugaletta, Luca. "Randomized configuration for Algorithm Selector SUNNY." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17573/.
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In questa tesi abbiamo analizzato i comportamenti dell'algoritmo Sunny andando a modificare il metodo di scelta delle feature, principalmente passando da un approccio sequenziale ad uno casuale.
Abbiamo implementato e confrontato 3 tecniche oltre a quella di partenza:
-randk: sfrutta un approccio puramente casuale per il calcolo delle n feature e della k.
-simann: sfrutta la tecnica di ottimizzazione di simulated annealing per calcolare le n feature e il valore di k.
-simann-mod: come simann, ma utilizza parametri diversi per il calcolo.
All'interno di questa tesi troviamo i risultati dell'esperimento e i vantaggi che si possono avere nell'utilizzo di una tecnica che non visita tutte le possibili soluzioni, ma solamente un numero ridotto di esse.
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Parry, Bryn Malcolm. "Fluctuating asymmetry and sexual selection in the freshwater crustacean Asellus aquaticus [L.]." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367197.
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Scegura, Amy. "Marker Assisted Backcross Selection for Virus Resistance in Pea (Pisum Sativum L.)." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28401.
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Viruses are destructive plant pathogens, which cause significant yield loss and reduced grain quality. Pea Seed-borne Mosaic Virus (PSbMV) is an economically important viral disease in pea (Pisum sativum L.) and recently detected in the Northern Great Plains (NGP) in 2012. PSbMV is aphid-transmitted from plant to plant and can be seed-borne. It causes malformed leaves, discolored or split seed, and reduced size and number of seeds. Host resistance to PSbMV-P4 is conferred by a recessive gene, sbm-1. Marker assisted backcross breeding using the 4Egenomic primers previously developed assisted in transferring the single resistance allele located on LG VI from ?Lifter? into locally adapted breeding lines. After two backcrosses and allowing plants to self-pollinate to the B2F2, individuals were inoculated with PSbMV-P4 isolate to validate resistance. The BC2F3 populations were tested in a field evaluation trial for disease resistance against the PSbMV-P4 strain in the NGP and for agronomic adaptation.
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Thornton, Nadia. "L-alanosine : selective treatment in relapsed childhood acute lymphoblastic leukaemia." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440588.
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Beattie, Aaron D. "Application of marker-assisted selection to breeding of common bean, Phaseolus vulgaris L." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33207.pdf.
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Khan, Mohd Golam Quader. "Marker-assisted selection in enhancing genetically male Nile tilapia (Oreochromis niloticus L.) production." Thesis, University of Stirling, 2011. http://hdl.handle.net/1893/2980.
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All-male fry are preferred to prevent uncontrolled reproduction before harvest in intensive Nile tilapia (Oreochromis niloticus) aquaculture. Males also grow faster than females. An alternative approach to direct hormonal masculinisation of tilapia fry is to produce fry that are genetically male. However, sex determination system in tilapia is fairly complex. Recent developments have resulted in a linkage map and genetic markers that can be used to analyse the sex determination system. To analyse the genetic sex determination mechanism and to develop marker-assisted selection in the Stirling Nile tilapia population, a fully inbred line of clonal females (XX) was verified using test crosses and DNA markers (mostly microsatellites) to use as a standard reference line in sex determination studies. A series of crosses were performed involving this line of females and a range of males. Three groups of crosses were selected (each group consisted of three families) from progeny sex ratio distributions, and designated as type ‘A’ (normal XY males x clonal XX females), type ‘B’ (putative YY males x clonal XX females) and type ‘C’ (unknown groups of males x clonal XX females), for sex linkage study. For type ‘A’, inheritance of DNA markers and phenotypic sex was investigated using screened markers from tilapia linkage group 1 (LG1) to confirm the LG1-associated pattern of inheritance of phenotypic sex and the structure of LG1. Screened markers from LG1, LG3 and LG23 were used to investigate the association of markers with sex in families of type ‘B’ and ‘C’. In addition, a genome-wide scan of markers from the other 21 LGs was performed to investigate any association between markers and sex, in only families of cross type ‘B’. LG1 associated pattern of inheritance of phenotypic sex was confirmed by genotype and QTL analyses in families of cross type ‘A’. Analyses of genotypes in families of type ‘B’ and ‘C’ showed strong association with LG1 markers but no association with LG3 and LG23 markers. Genome wide scan of markers from all other LGs did not show any significant association between any markers and the sex. The allelic inheritance of two tightly linked LG1 markers (UNH995 and UNH104) in families of type ‘B’ and ‘C’ identified polymorphism in the sex determining locus: one of the alleles was associated mostly with male offspring whereas another allele was associated with both progeny (mostly males in type ‘B’ families, and approximately equal numbers in type ‘C’ families). This knowledge was used to identify and separate supermales (‘YY’ males) that should sire higher proportions of male progeny, reared to become sexually mature for use as broodstock. Two of them were crossed with XX females (one clonal and one outbred) to observe the phenotypic expression of the strongest male-associated allele in progeny sex. The observations of 98% male (99 males out of 101 progeny) and 100% male (N=75) from these two crosses respectively, suggest that a marker-assisted selection (MAS) programme for genetically male Nile tilapia production could be practical. This study also suggests that the departures from the sex ratios predicted using a “simple” XX/XY model (i.e., YY x XX should give all-male progeny) were strongly associated with the XX/XY system, due to multiple alleles, rather than being associated with loci in other LGs (e.g., LG3, LG23). This study also tentatively names the allele(s) giving intermediate sex ratios as “ambivalent” and emphasizes that the presence and actions of such allele(s) at the same sex-determining locus could explain departures from predicted sex ratios observed in some earlier studies in Nile tilapia.
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Karanja, N. K. "Selecting Rhizobium phaseoli strains for use with beans (Phaseolus vugaris L.) in Kenya." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383603.
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Bruno, Elisabetta. "Habitat selection and feeding ecology of red (Cervus elaphus L.) and roe (Capreolus capreolus L.) deer in the Central Apennines, Italy." Thesis, University of Aberdeen, 1996. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU083115.
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This study investigated the ecology of red and roe deer in a protected area of Central Apennines in Italy in 1992 and 1993, with particular reference to the habitat selection in relation to food resources and the botanical composition of the diet of the two deer species and their inter-relationships. In addition, deer population densities were estimated and their impact on woody vegetation was assessed. Habitat selection by red and roe deer in relation to food resources of habitats was investigated by pellet group counts. Red deer used a wider range of habitats, preferring Deciduous Wood in winter and Rocky and Steep Meadow in summer and autumn, while roe deer selected woods with thick undergrowth and conifers, with no marked seasonal variation. Both deer species avoided Beech Woods, which provided the least undergrowth and cover. Red deer showed a higher use than roe deer of all habitats except of Mixed Wood where it was similar. The patterns of habitat selection shown by the two deer species seemed to reflect their ecological requirements, although seasonal interspecific competition was suggested for the use of some habitats. The diet of red and roe deer was investigated by microhistological analysis of faeces. An anatomical key of food plants was created to identify food categories. Red deer ate mainly Monocotyledonous Herbs, especially in winter, as well as Deciduous Trees (in autumn) and Conifers (in spring). Dicotyledonous Herbs and Shrubs were the least frequent food category, eaten mainly in summer and autumn. Roe deer diet was composed relatively equally by all the food categories, with little seasonal variation. However, Deciduous Trees and Conifers, combined, were the most consumed foods. Within the tree food categories, roe deer showed a preference for Conifers, whereas the selection for them by red deer probably depended on the seasonal availability of Deciduous Trees.
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Silva, Patrick Fernandes da. "Avaliação do efeito imunomodulador da lectina extraída de Brassica oleracea sobre neutrófilos." Universidade Federal de Viçosa, 2017. http://www.locus.ufv.br/handle/123456789/11605.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Neutrófilos são as primeiras células do sistema imune a migrarem para o tecido inflamado e exercem a importante função de fagocitose e eliminação imediata de patógenos invasores. A ativação de neutrófilos é um processo de múltiplos passos e de alta complexidade. A busca por agentes biológicos capazes de modular o processo de ativação, migração, fagocitose e produção de espécies reativas de oxigênio (ROS) é importante pois aumentam a gama de opções para utilização na pesquisa. Nesse trabalho utilizamos a lectina extraída de Brassica oleracea (BOL) a fim de avaliar a sua capacidade na modulação da resposta de neutrófilos. Para os ensaios nós purificamos neutrófilos de camundongo tanto do sangue periférico quanto da cavidade peritoneal buscando avaliar sua capacidade migratória, o índice de CD62L na superfície e o índice fagocítico de neutrófilos pré-incubados com BOL. A lectina apresentou diversos efeitos de acordo com a dose utilizada, sendo possível observar o efeito de indução de migração para cavidade peritoneal de camundongos quando utilizada em doses intermediárias (1 μg/mL e 2,5 μg/mL) tanto quanto o efeito de redução de migração quando observada em doses altas (5 μg/mL e 10 μg/mL). O índice de fagocitose também foi avaliado e houve alteração de acordo também com a dose utilizada. As doses mais altas apresentaram efeito de redução na taxa de fagocitose (5 μg/mL e 10 μg/mL) enquanto as outras doses não apresentavam diferença estatística. Com esse trabalho conseguimos observar os efeitos imunomodulatórios sobre neutrófilos de uma lectina ainda muito pouco estudada e que demonstrou ter efeitos sobre a fisiologia de neutrófilos de acordo com a dose escolhida, alterando sua capacidade de migração e fagocitose.
Neutrophils are the first cells of the immune system to migrate into inflamed tissue and they develop the important function of phagocytosis and immediate elimination of invading pathogens. Neutrophil activation is a multi-step and highly complex process. Research on biological agents able to modulate the activation, migration, phagocytosis and production of reactive oxygen species (ROS) are important because they increase the range of options for use in the research. In this work we used the lectin extracted from Brassica oleracea (BOL) aiming to evaluate its ability to modulate the neutrophil response. For the tests, we purified mouse neutrophils from the peripheral blood and the peritoneal cavity with the objective to evaluate their migratory capacity, the surface CD62L index and the phagocytic index of neutrophils pre-incubated with BOL. The lectin presented several effects according to the dose used, being possible to observe the effect of induction of migration to peritoneal cavity when it was used in intermediate doses (1 μg/mL and 2.5 μg/mL) as well as the effect of reduction of migration as observed at high doses (5 μg/ mL and 10 μg/mL). The phagocytosis index was also evaluated and there was also an alteration according to the dose used. Higher doses showed a smaller phagocytosis rate (5 μg/mL and 10 μg/mL), unlike the other doses. In this work we were able to observe the immunomodulatory effects on neutrophils of a lectin that has not yet been studied and has shown to have effects on neutrophil physiology according to the chosen dose, altering its migration capacity and phagocytosis.
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Bateson, Janice Mary. "In vitro selection and characterization of lead resistant somaclonal variants from Daucus carota L." Thesis, University of Plymouth, 1990. http://hdl.handle.net/10026.1/2437.
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Lead was shown to inhibit both callus initiation and callus growth in cultures of Daucus carota L. subsp. sativus (Hoff. Thell.) cv. Nantes ''Tiptop'' and ''Nanthya''. Taproot explants of Daucus carota were stressed with lead. The callus cell lines which initiated under this stress were shown to exhibit resistance to the effects of lead ions. The growth of the selected and nonselected cell lines on non-lead containing media was comparable and the resistance possessed by the selected cell lines did not result in reduced growth rates in the presence of lead. The resistance characteristic was shown to be stable and to be successfully transmitted over mitotic and meiotic barriers. Plants were regenerated from the selected cell lines and ion uptake studies were conducted on isolated cortical tissue from mature taproots. The uptake of lead into the cortical cell tissue from the selected lines was shown to be reduced and a greater proportion of the lead that did enter the tissue was present in the Apparent Free Space and did not enter the cells. The regenerated plants were self-pollenated to produce an F1 generation. F1 plantlets were grown in hydroponic culture containing various concentrations of lead. The selected plants were seen to be resistant to the lead stress. The sites of lead accumulation in these roots were determined using x-ray microanalysis in a scanning electron microscope with a cryo-stage. The lead was found to be associated with the epidermal layer and cell walls. The mechanism of the lead resistance is discussed along with the implications of selection for somaclonal variants from initiating callus cultures.
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Sloan, S. "Assessment, modification and consequences of shell selection in the hermit crab, Pagurus bernhardus (L.)." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390860.
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