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Control of Ca'2'+ signalling in rat lactotrophsCarew, Mark Andrew January 1995 (has links)
No description available.
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CO₂ Mineralization Using Reactive SpeciesMa, Juan 22 May 2012 (has links)
To address the environmental changes associated with increasing levels of atmospheric CO?, a possibility of mineralizing CO? with the species such as Ca°? and M°? ions that are already present in sea water was studied. A series of experiments conducted at temperatures in the range of 20 to 40°C showed that the activation energy for the formation of nesquehonite (MgCO?°3H?O) is 64.6 kJ/mol. It was found that the activation energy barrier can be readily overcome by simple agitation and heating at slightly elevated temperatures, e.g., 40°C. The kinetics of mineralization and the %M°? ion utilization varies depending on energy dissipation rate, temperature, pH, and NaCl concentration. The maximum M°? ion utilization achieved was 86%. Thermodynamic calculations were carried out to construct the species distribution diagrams, predict the pH of CO? mineralization, and to predict %Mg ion utilization (or extraction) from sea water.
To address the issues concerning the acidification of sea water during CO? mineralization, spent solutions were treated with basic minerals such as limestone and olivine. It was found that in the presence of these minerals the pH rises to the pH of minimum solubility of the buffering mineral. The pH of minimum solubility of limestone is 8.3 and that of olivine is 8.6. Other means of pH neutralization were also discussed. / Master of Science
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Assessment of Cerebellar and Hippocampal Morphology and Biochemical Parameters in the Compound Heterozygous, Tottering/leaner MouseMurawski, Emily M. 2009 December 1900 (has links)
Due to two different mutations in the gene that encodes the a1A subunit of
voltage-activated CaV 2.1 calcium ion channels, the compound heterozygous
tottering/leaner (tg/tgla) mouse exhibits numerous neurological deficits. Human
disorders that arise from mutations in this voltage dependent calcium channel are
familial hemiplegic migraine, episodic ataxia-2, and spinocerebellar ataxia 6. The tg/tgla
mouse exhibits ataxia, movement disorders and memory impairment, suggesting that
both the cerebellum and hippocampus are affected. To gain greater understanding of the
many neurological abnormalities that are exhibited by the 90-120 day old tg/tgla mouse
the following aspects were investigated: 1) the morphology of the cerebellum and
hippocampus, 2) proliferation and death in cells of the hippocampal dentate gyrus and 3)
changes in basic biochemical parameters in granule cells of the cerebellum and
hippocampus.
This study revealed no volume abnormalities within the hippocampus of the
mutant mice, but a decrease in cell density with the pyramidal layer of CA3 and the hilus
of the dentate gyrus. Cell size in the CA3 region was unaffected, but cell size in the hilus of the dentate gyrus did not exhibit the gender difference seen in the wild type
mouse. The cerebellum showed a decrease in volume without any decrease in cerebellar
cellular density. Cell proliferation and differentiation in the subgranular zone of the
hippocampal dentate gyrus remained normal. This region also revealed a decrease in
cell death in the tg/tgla mice.
Basal intracellular calcium levels in granule cells show no difference within the
hippocampus, but an increase in the tg/tgla male cerebellum compared to the wild type
male cerebellum. There was no significant difference in granule cell mitochondrial
membrane potential within the wild type and mutant animals in either the hippocampus
or cerebellum. The rate of reactive oxygen species (ROS) production in granule cells
revealed no variation within the hippocampus or cerebellum. The amount of ROS was
decreased in cerebellar granule cells, but not granule cells of the hippocampus. Inducing
ROS showed no alteration in production or amount of ROS produced in the
hippocampus, but did show a ceiling in the amount of ROS produced, but not rate of
production, in the cerebellum.
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Síntese enzimática de peptídeos contendo asparagina e transesterificação de seus ésteres de peptídeos na presença de Ca(II) / Enzymatics synthesis of peptides containing asparagine and transesterification it esters of peptides in the presence of CA (II)Miranda, Maria Teresa Machini de 19 September 1989 (has links)
Visando dar continuidade ao estudo de incorporação de N-acil-asparagina a derivados de aminoácidos e a peptídeos mediante catálise por termolisina, foi estudada a viabilidade de síntese dos peptídeos Z-Asn-Cys(S-Bzl)-OBut e Moz-Asn-Cys(S-Bzl)-Pro-Leu-Gly-NH2. Durante a síntese do pentapeptídeo Moz-Asn-Cys(S-Bzl)-Pro-Leu-Gly-NH2 foi constatada a formação de um subproduto cuja estrutura foi elucidada a partir da comparação ao padrão autêntico Moz-Asn-Leu-Gly-NH2. Para a obtenção deste padrão, sintetizamos o tripeptídeo Moz-Asn-Leu-Gly-OEt a partir de Moz-Asn-OH e H-Leu-Gly-OEt na presença de termolisina. A recristalização deste peptídeo em MeOH/H2 O levou à transformação do mesmo em Moz-Asn-Leu-Gly-OMe, confirmada pelo isolamento e caracterização do produto por espectrometria de massa e ressonância magnética protônica, análise elementar e de aminoácidos e por determinação do tempo de retenção por HPLC. Estudos posteriores demonstraram o envolvimento do íon Ca(II) no processo e nos permitiram sugerir um modelo da ligação deste íon ao peptídeo e da sequência de reação da transesterificação estudada. Também foi investigada a possibilidade de diversos ésteres de peptídeos e de peptidilresinas de Merrifield sofrerem transesterificação quando incubados em metanol na presença de Ca(II). Para tanto, os tripeptídeos Z-Asn-Leu-Gly-OEt, Boc-Asn-Leu-Gly-OEt, Moz-Asn-Leu-Gly-OBzl, Moz-Asn-Leu-Gly-OBu Moz-Gln-Leu-Gly-OEt, Moz-Asn-Ile-Gly-OEt e Moz-Asn-Leu-Ala-OEt foram sintetizados mediante catálise por termolisina. Também foram testados vários outros peptídeos disponíveis no laboratório e Boc-Leu-Gly-Res e Moz-Asn-Leu-Gly-Res. Com exceção dos ésteres terc-butílicos, todos sofreram transesterificação em soluções metanólicas de acetato de cálcio. / The main obJective was the study of thermolysin catalyzed incorporation of N-acyl-asparagine into amino acid and peptide derivatives. Both Z-Asn-Cys(S-Bzl)-OBut and Moz-Asn-Cys(S-Bzl)-Pro-Leu-Gly-NH2 syntheses have been studied. The formation of a by-product occurred during the synthesis of the later pentapeptide. By comparison with an authentic standard this by-product was identified as Moz-Asn-Leu-Gly-NH2. The standard Moz-Asn-Leu-Gly-NH2 was obtained by aminolYSlS of Moz-Asn-Leu-Gly-OEt. This peptide was synthesized by coupling Moz-Asn-OH with H-Leu-Gly-OEt using thermolysin as catalyst. During the recrystallization in MeOH/H2O, the transformation of Moz-Asn-Leu-Gly-OEt to its methyl-ester was obtained. This observation has been confirmed by purification and caracterization of the peptide by: Mass Spectroscopy, Nuclear Magnetic Ressonance, Amino Acid and Elemental Analysis and HPLC. Later studies have shown that the Ca(II) ion participates in the process. A model for the binding of this ion to the peptide and for the transesterification reaction has been suggested. Further studies have been performed with (1) the newly synthesized peptides Z-Asn-Leu-Gly-OEt, Boc-Asn-Leu-Gly-OEt, Moz-Asn-Leu-Gly-OBzl, Moz-Asn-Leu-Gly-OBut, Moz-Gln-Leu-Gly-OEt, Moz- Asn-Ile-Gly-OEt and Moz-Asn-Leu-Ala-OEt; (2) several other peptides available in our laboratory; and (3) Boc-Leu-Gly-Res and Moz-Asn-Leu-Gly-Res. With the exception of t-butyl-esters, all peptides tested have transesterified in methanolic calcium acetate solutions.
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The Mechanotransduction of Hydrostatic Pressure by Mesenchymal Stem CellsSeyedeh Ghazaleh Hosseini (5931062) 17 January 2019 (has links)
<div>Mesenchymal stem cells (MSCs) are responsive to mechanical stimuli that play an essential role in directing their differentiation to the chondrogenic lineage. A better</div><div>understanding of the mechanisms that allow MSCs to respond to mechanical stimuli is important to improving cartilage tissue engineering and regenerative medicine. Hydrostatic pressure (HP) in particular is known to be a primary mechanical force in joints. However, little is known about the underlying mechanisms that facilitate HP</div><div>mechanotransduction. Understanding the signaling pathways in MSCs in transducing HP to a beneficial biologic response and their interrelationship were the focus of this thesis. Studies used porcine marrow-derived MSCs seeded in agarose gel. Calcium ion Ca++ signaling, focal adhesion kinase (FAK) involvement, and sirtuin1 activity were investigated in conjunction with HP application.</div><div><br></div><div><div>Intracellular Ca++ concentration was previously shown to be changed with HP application. In our study a bioreactor was used to apply a single application of HP to the MSC-seeded gel structures and observe Ca++ signaling via live imaging of a fluorescent calcium indicator in cells. However, no fluctuations in Ca++ concentrations were observed with 10 minutes loading of HP. Additionally a problem with the biore actor design was discovered. First the gel was floating around in the bioreactor even without loading. After stabilizing the gel and stopping it from floating, there were still about 16 µm of movement and deformation in the system. The movement and deformation was analyzed for the gel structure and different parts of the bioreactor. </div><div><br></div><div>Furthermore, we investigated the role of FAK in early and late chondrogenesis and also its involvement in HP mechanotransduction. A FAK inhibitor was used on MSCs from day 1 to 21 and showed a dose-dependent suppression of chondrogenesis. However, when low doses of FAK inhibitor added to the MSC culture from day 21 to 42, chondrogenesis was not inhibited. With 4 hour cyclic HP, FAK phosphorylation increased. The beneficial effect of HP was suppressed with overnight addition of the</div></div><div><div>FAK inhibitor to MSC medium, suggesting FAK involvement in HP mechanotransducation by MSCs.</div></div><div><br></div><div>Moreover, sirtuin1 participation in MSC chondrogenesis and mechanotransduction was also explored. The results indicated that overnight sirtuin1 inhibition increased chondrogenic gene expression (Agc, Col2, and Sox9) in MSCs. Additionally, the activity of sirtuin1 was decreased with both 4 hour cyclic hydrostatic pressure and inhibitor application. These two together demonstrated that sirtuin1 inhibition enhances chondrogenesis.</div><div><br></div><div><div>In this research we have investigated the role of Ca++ signaling, FAK involvement, and sirtuin1 activity in the mechanotransduction of HP in MSCs. These understandings about the mechanisms regulating the chondrogenesis with respect to HP could have important implications for cartilage tissue engineering and regenerative studies.</div></div>
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Role of magnesium ions in the excitation of vascular smooth muscle : effects of hypermagnesaemia and hypomagnesaemia on drug-induced contractions of mammalian arteries with special reference to the involvement of changed tissue calcium ion concentration or distribution in the observed responsesAsmawi, Mohd. Zaini January 1982 (has links)
Studies on the perfused rabbit ear artery preparation showed that withdrawal of Mg 2+ from extracellular fluid potentiated the responses to histamine and ATP but not to catecholamines. Similar results were obtained in [2xCa2+] Krebs solution. Increases in [Mg 2+] decreased responses to the three agonists to a similar extent. In subsequent experiments attempts were made to alter the availability of calcium for contraction induced by these agonists either by changing the [Ca 2+] of the Krebs solution or by using Ca 2+ influx inhibitors, ouabain and ryanodine. The effects of these agonists were compared to those observed when Mg2+ was altered. In general, the results obtained in perfused rabbit ear artery supported the hypothesis that changes in extracellular [Mg2+] affect the availability of calcium for contraction but were not consistent with the suggestion that Mg2+ alters Ca2+ influx. In a second type of preparation tension responses of superfused rings of ear artery were studied. Responses to changes in extracellular [Ca2+] and[ Mg2+] were found to differ slightly from those obtained in the perfused artery. A simultaneously perfused and superfused arterial preparation showed that responses to changes in [ Mg2+] and[Ca2+] were different if the agonist was administered to the adventitial surface of the vessel rather than via the intimal surface. The effects of alterations in extracellular [Mg 2+] were studied in mesenteric arteries from weight matched normotensive and spontaneously hypertensive rats (SHR). No differences in response to NA or ATP when extracellular [Mg 2+ ] was either increased or reduced were observed in the SHR compared to the normotensive animal. However, a difference in calcium dependence was demonstrated between the two types of vessels to NA. In contrast to mesenteric arteries, experiments on aortae from normotensive rats and SHR showed no differences in the calcium dependence of NA responses between normotensive and SHR vessels, whereas, [4xMg2+ ] Krebs solution reduced the responses of normotensive aorta to NA more than SHR. These results in the rat were not consistent with the hypothesis that alteration in [Mg 2+] can be explained in terms of altered calcium availability. Attempts to increase intracellular cyclic AMP with theophylline showed that the response to ED50 NA in both mesenteric arteries and aortae from normotensive were reduced more than SHR. It is concluded that the effect of changes in extracellular [Mg2+] on the reactivity of vascular muscle varies depending on the type of vessel and species of animal from which the vessel is taken. In addition when all the experimental results are considered, it is not possible to explain all the actions of altered [ Mg2+ ] simply in terms of changed calcium availability.
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AtNOGC1 protein bioelectrode for the determination of stress signalling molecules - Nitric Oxide (NO), Carbon Monoxide (CO) and Calcium ion (Ca2+)Tshivhidzo, Tsumbedzo Tertius January 2018 (has links)
Magister Scientiae - MSc (Biotechnology) / It has been estimated that the world population will reach about 10 billion by the year 2050 and in order to accommodate the increased demand of food, the world agricultural production needs to rise by 70 % in the year 2030. However, the realisation of the goal in food production is hindered by limited arable land caused by urbanisation, salinisation, desertification and environmental degradation. Furthermore, abiotic and biotic stresses affect plant growth and development, which lead to major crop losses. The long term goal of this study is to improve food security by producing genetically engineered agricultural crops that will be tolerant to diverse stresses. This research aims at developing stress tolerant crops through the determination of important signalling molecules and second messengers, such as nitric oxide (NO), carbon monoxide (CO) and calcium ion (Ca2+), which can bind to plant proteins such as AtNOGC1 in order to induce stress tolerance in plants.
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Síntese enzimática de peptídeos contendo asparagina e transesterificação de seus ésteres de peptídeos na presença de Ca(II) / Enzymatics synthesis of peptides containing asparagine and transesterification it esters of peptides in the presence of CA (II)Maria Teresa Machini de Miranda 19 September 1989 (has links)
Visando dar continuidade ao estudo de incorporação de N-acil-asparagina a derivados de aminoácidos e a peptídeos mediante catálise por termolisina, foi estudada a viabilidade de síntese dos peptídeos Z-Asn-Cys(S-Bzl)-OBut e Moz-Asn-Cys(S-Bzl)-Pro-Leu-Gly-NH2. Durante a síntese do pentapeptídeo Moz-Asn-Cys(S-Bzl)-Pro-Leu-Gly-NH2 foi constatada a formação de um subproduto cuja estrutura foi elucidada a partir da comparação ao padrão autêntico Moz-Asn-Leu-Gly-NH2. Para a obtenção deste padrão, sintetizamos o tripeptídeo Moz-Asn-Leu-Gly-OEt a partir de Moz-Asn-OH e H-Leu-Gly-OEt na presença de termolisina. A recristalização deste peptídeo em MeOH/H2 O levou à transformação do mesmo em Moz-Asn-Leu-Gly-OMe, confirmada pelo isolamento e caracterização do produto por espectrometria de massa e ressonância magnética protônica, análise elementar e de aminoácidos e por determinação do tempo de retenção por HPLC. Estudos posteriores demonstraram o envolvimento do íon Ca(II) no processo e nos permitiram sugerir um modelo da ligação deste íon ao peptídeo e da sequência de reação da transesterificação estudada. Também foi investigada a possibilidade de diversos ésteres de peptídeos e de peptidilresinas de Merrifield sofrerem transesterificação quando incubados em metanol na presença de Ca(II). Para tanto, os tripeptídeos Z-Asn-Leu-Gly-OEt, Boc-Asn-Leu-Gly-OEt, Moz-Asn-Leu-Gly-OBzl, Moz-Asn-Leu-Gly-OBu Moz-Gln-Leu-Gly-OEt, Moz-Asn-Ile-Gly-OEt e Moz-Asn-Leu-Ala-OEt foram sintetizados mediante catálise por termolisina. Também foram testados vários outros peptídeos disponíveis no laboratório e Boc-Leu-Gly-Res e Moz-Asn-Leu-Gly-Res. Com exceção dos ésteres terc-butílicos, todos sofreram transesterificação em soluções metanólicas de acetato de cálcio. / The main obJective was the study of thermolysin catalyzed incorporation of N-acyl-asparagine into amino acid and peptide derivatives. Both Z-Asn-Cys(S-Bzl)-OBut and Moz-Asn-Cys(S-Bzl)-Pro-Leu-Gly-NH2 syntheses have been studied. The formation of a by-product occurred during the synthesis of the later pentapeptide. By comparison with an authentic standard this by-product was identified as Moz-Asn-Leu-Gly-NH2. The standard Moz-Asn-Leu-Gly-NH2 was obtained by aminolYSlS of Moz-Asn-Leu-Gly-OEt. This peptide was synthesized by coupling Moz-Asn-OH with H-Leu-Gly-OEt using thermolysin as catalyst. During the recrystallization in MeOH/H2O, the transformation of Moz-Asn-Leu-Gly-OEt to its methyl-ester was obtained. This observation has been confirmed by purification and caracterization of the peptide by: Mass Spectroscopy, Nuclear Magnetic Ressonance, Amino Acid and Elemental Analysis and HPLC. Later studies have shown that the Ca(II) ion participates in the process. A model for the binding of this ion to the peptide and for the transesterification reaction has been suggested. Further studies have been performed with (1) the newly synthesized peptides Z-Asn-Leu-Gly-OEt, Boc-Asn-Leu-Gly-OEt, Moz-Asn-Leu-Gly-OBzl, Moz-Asn-Leu-Gly-OBut, Moz-Gln-Leu-Gly-OEt, Moz- Asn-Ile-Gly-OEt and Moz-Asn-Leu-Ala-OEt; (2) several other peptides available in our laboratory; and (3) Boc-Leu-Gly-Res and Moz-Asn-Leu-Gly-Res. With the exception of t-butyl-esters, all peptides tested have transesterified in methanolic calcium acetate solutions.
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The Mechanotransduction of Hydrostatic Pressure by Mesenchymal Stem CellsHosseini, Seyedeh Ghazaleh 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Mesenchymal stem cells (MSCs) are responsive to mechanical stimuli that play an
essential role in directing their differentiation to the chondrogenic lineage. A better
understanding of the mechanisms that allow MSCs to respond to mechanical stimuli
is important to improving cartilage tissue engineering and regenerative medicine.
Hydrostatic pressure (HP) in particular is known to be a primary mechanical force in
joints. However, little is known about the underlying mechanisms that facilitate HP
mechanotransduction. Understanding the signaling pathways in MSCs in transducing
HP to a beneficial biologic response and their interrelationship were the focus of this
thesis. Studies used porcine marrow-derived MSCs seeded in agarose gel. Calcium ion Ca++ signaling, focal adhesion kinase (FAK) involvement, and sirtuin1 activity
were investigated in conjunction with HP application.
Intracellular Ca++ concentration was previously shown to be changed with HP
application. In our study a bioreactor was used to apply a single application of HP to the MSC-seeded gel structures and observe Ca++ signaling via live imaging of a fluorescent calcium indicator in cells. However, no fluctuations in Ca++ concentrations
were observed with 10 minutes loading of HP. Additionally a problem with the biore
actor design was discovered. First the gel was floating around in the bioreactor even
without loading. After stabilizing the gel and stopping it from floating, there were
still about 16 µm of movement and deformation in the system. The movement and
deformation was analyzed for the gel structure and different parts of the bioreactor.
Furthermore, we investigated the role of FAK in early and late chondrogenesis
and also its involvement in HP mechanotransduction. A FAK inhibitor was used on
MSCs from day 1 to 21 and showed a dose-dependent suppression of chondrogenesis.
However, when low doses of FAK inhibitor added to the MSC culture from day 21 to
42, chondrogenesis was not inhibited. With 4 hour cyclic HP, FAK phosphorylation
increased. The beneficial effect of HP was suppressed with overnight addition of the
FAK inhibitor to MSC medium, suggesting FAK involvement in HP mechanotransd
ucation by MSCs.
Moreover, sirtuin1 participation in MSC chondrogenesis and mechanotransduc
tion was also explored. The results indicated that overnight sirtuin1 inhibition in
creased chondrogenic gene expression (Agc, Col2, and Sox9) in MSCs. Additionally,
the activity of sirtuin1 was decreased with both 4 hour cyclic hydrostatic pressure
and inhibitor application. These two together demonstrated that sirtuin1 inhibition
enhances chondrogenesis.
In this research we have investigated the role of Ca++ signaling, FAK involvement,
and sirtuin1 activity in the mechanotransduction of HP in MSCs. These understand
ings about the mechanisms regulating the chondrogenesis with respect to HP could
have important implications for cartilage tissue engineering and regenerative studies.
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Role of magnesium ions in the excitation of vascular smooth muscle. Effects of hypermagnesaemia and hypomagnesaemia on drug-induced contractions of mammalian arteries with special reference to the involvement of changed tissue calcium ion concentration or distribution in the observed responses.Asmawi, Mohd. Z. January 1982 (has links)
Studies on the perfused rabbit ear artery preparation showed that
withdrawal of Mg 2+ from extracellular fluid potentiated the responses
to histamine and ATP but not to catecholamines. Similar results were
obtained in [2xCa2+] Krebs solution. Increases in [Mg 2+] decreased
responses to the three agonists to a similar extent. In subsequent
experiments attempts were made to alter the availability of calcium for
contraction induced by these agonists either by changing the [Ca 2+]
of the Krebs solution or by using Ca 2+ influx inhibitors, ouabain and
ryanodine. The effects of these agonists were compared to those
observed when Mg2+ was altered. In general, the results obtained
in perfused rabbit ear artery supported the hypothesis that changes in
extracellular [Mg2+] affect the availability of calcium for contraction
but were not consistent with the suggestion that Mg2+ alters Ca2+ influx.
In a second type of preparation tension responses of superfused
rings of ear artery were studied. Responses to changes in extracellular
[Ca2+] and[ Mg2+] were found to differ slightly from those
obtained in the perfused artery. A simultaneously perfused and
superfused arterial preparation showed that responses to changes in
[ Mg2+] and[Ca2+] were different if the agonist was administered to
the adventitial surface of the vessel rather than via the intimal
surface.
The effects of alterations in extracellular [Mg 2+] were studied in mesenteric arteries from weight matched normotensive and spontaneously
hypertensive rats (SHR). No differences in response to NA or
ATP when extracellular [Mg 2+ ] was either increased or reduced were
observed in the SHR compared to the normotensive animal. However,
a difference in calcium dependence was demonstrated between the two
types of vessels to NA. In contrast to mesenteric arteries, experiments
on aortae from normotensive rats and SHR showed no differences
in the calcium dependence of NA responses between normotensive and
SHR vessels, whereas,
[4xMg2+ ] Krebs solution reduced the responses
of normotensive aorta to NA more than SHR. These results in the
rat were not consistent with the hypothesis that alteration in [Mg 2+]
can be explained in terms of altered calcium availability. Attempts
to increase intracellular cyclic AMP with theophylline showed that
the response to ED50 NA in both mesenteric arteries and aortae from
normotensive were reduced more than SHR.
It is concluded that the effect of changes in extracellular [Mg2+]
on the reactivity of vascular muscle varies depending on the type of
vessel and species of animal from which the vessel is taken. In
addition when all the experimental results are considered, it is not
possible to explain all the actions of altered [ Mg2+ ] simply in
terms of changed calcium availability.
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