scholarly journals Regulation by copper of the expression of plastocyanin and cytochrome c552 in Chlamydomonas reinhardi.

1986 ◽  
Vol 6 (2) ◽  
pp. 462-469 ◽  
Author(s):  
S Merchant ◽  
L Bogorad
Keyword(s):  
Molecular Level ◽  
The Other ◽  
Mature Protein ◽  
Cytochrome C552 ◽  
Translatable Mrna ◽  
Electron Carriers ◽  
Different Levels ◽  
Polyadenylated Mrna ◽  
Photosynthetic Electron Transfer

Plastocyanin and cytochrome c552 are interchangeable electron carriers in the photosynthetic electron transfer chains of some cyanobacteria and green algae (P. M. Wood, Eur. J. Biochem. 87:9-19, 1978; G. Sandmann et al., Arch. Microbiol. 134:23-27, 1983). Chlamydomonas reinhardi cells respond to the availability of copper in the medium and accordingly accumulate either plastocyanin (if copper is available) or cytochrome c552 (if copper is not available). The response occurs in both heterotrophically and phototrophically grown cells. We have studied the molecular level at which this response occurs. No immunoreactive polypeptide is detectable under conditions where the mature protein is not spectroscopically detectable. Both plastocyanin and cytochrome c552 appear to be translated (in vitro) from polyadenylated mRNA as precursors of higher molecular weight. RNA was isolated from cells grown either under conditions favorable for the accumulation of plastocyanin (medium with Cu2+) or for the accumulation of cytochrome c552 (without Cu2+ added to the medium). Translatable mRNA for preapoplastocyanin was detected in both RNA preparations, although mature plastocyanin was detected in C. reinhardi cells only when copper was added to the culture. Translatable mRNA for preapocytochrome, on the other hand, was detected only in cells grown under conditions where cytochrome c552 accumulates (i.e., in the absence of copper). We conclude that copper-mediated regulation of plastocyanin and cytochrome c552 accumulation is effected at different levels, the former at the level of stable protein and the latter at the level of stable mRNA.

Regulation by copper of the expression of plastocyanin and cytochrome c552 in Chlamydomonas reinhardi

1986 ◽  
Vol 6 (2) ◽  
pp. 462-469
Author(s):  
S Merchant ◽  
L Bogorad
Keyword(s):  
Molecular Level ◽  
The Other ◽  
Mature Protein ◽  
Cytochrome C552 ◽  
Translatable Mrna ◽  
Electron Carriers ◽  
Different Levels ◽  
Polyadenylated Mrna ◽  
Photosynthetic Electron Transfer

Plastocyanin and cytochrome c552 are interchangeable electron carriers in the photosynthetic electron transfer chains of some cyanobacteria and green algae (P. M. Wood, Eur. J. Biochem. 87:9-19, 1978; G. Sandmann et al., Arch. Microbiol. 134:23-27, 1983). Chlamydomonas reinhardi cells respond to the availability of copper in the medium and accordingly accumulate either plastocyanin (if copper is available) or cytochrome c552 (if copper is not available). The response occurs in both heterotrophically and phototrophically grown cells. We have studied the molecular level at which this response occurs. No immunoreactive polypeptide is detectable under conditions where the mature protein is not spectroscopically detectable. Both plastocyanin and cytochrome c552 appear to be translated (in vitro) from polyadenylated mRNA as precursors of higher molecular weight. RNA was isolated from cells grown either under conditions favorable for the accumulation of plastocyanin (medium with Cu2+) or for the accumulation of cytochrome c552 (without Cu2+ added to the medium). Translatable mRNA for preapoplastocyanin was detected in both RNA preparations, although mature plastocyanin was detected in C. reinhardi cells only when copper was added to the culture. Translatable mRNA for preapocytochrome, on the other hand, was detected only in cells grown under conditions where cytochrome c552 accumulates (i.e., in the absence of copper). We conclude that copper-mediated regulation of plastocyanin and cytochrome c552 accumulation is effected at different levels, the former at the level of stable protein and the latter at the level of stable mRNA.

scholarly journals EFFECT OF HEPARIN, ESTROGEN ON EPIDIDYMAL SPERM CAPACITATION AND IN VITRO FERTILIZATION IN IRAQI SHEEP

2020 ◽  
Vol 51 (Special) ◽  
Author(s):  
Ali & Saleh
Keyword(s):  
In Vitro Fertilization ◽  
Breeding Season ◽  
Positive Relationship ◽  
The Other ◽  
Epididymal Sperm ◽  
Vitro Fertilization ◽  
Index Level ◽  
Estrogen Concentration ◽  
Different Levels

This study was designed to study the capacitation of caudal spermatozoa in vitro by different levels of heparin, estrogen for in vitro fertilization (IVF) in the Iraqi local sheep. Results of sperm capcitation (massive motility percentage) by applying three levels of heparin (50, 100, 150) IU in relation to breeding season showed no significant differences during breeding season with the three levels, which were (82.23 ± 0.58), While results by applying the higher level of heparin (150) IU out of breeding season showed significantly (P<0.05) more and active motility Which were (62.07 ± 0.62) than the other levels (56.85 ± 0.61). At the same time applications result of three estrogen levels (20, 40, 60) mg on sperm capcitation showed Positive relationship between concentrations and (massive motility percentage), which showed the highest concentration gave the best results during and out of breeding season (87.20 ± 0.60) and (65.86 ± 0.62) respectively. with significant differences (P<0.05) between the three levels. While the results of the in vitro fertilization (IVF) index which reflected the sperm capcitation were recorded with the highest estrogen concentration during breeding season (22.70 %) compared with the best heparin level (20 %) while she was (10.45 %), (8.70 %) out of breeding season Sequentially, in which the highest estrogen concentration gives a best capacitation and IVF index level compared with the high heparin level over the year.

Copper and nickel pollution: frequency of endophytic fungi in Scots pine shoots and endophyte growth in vitro

1994 ◽  
Vol 72 (1) ◽  
pp. 93-99 ◽  
Author(s):  
H. Ranta ◽  
S. Neuvonen ◽  
S. Kääriäinen ◽  
S. Vesanto
Keyword(s):  
Heavy Metal ◽  
Scots Pine ◽  
Endophytic Fungi ◽  
Linear Growth ◽  
The Other ◽  
Unpolluted Area ◽  
Pine Trees ◽  
Heavily Polluted Area ◽  
Different Levels

The frequency of endophytic microfungi was measured from current-year shoots of Scots pine trees growing in Harjavalta, a heavily polluted area in western Finland. The copper (Cu) and (Ni) concentrations in bark plus phloem and needles of the same trees were measured. The frequency of isolates of endophytic taxa were either negatively (Hormonema sp. 2 and Sterile sp. 1) or positively (Hormonema sp. 1, BL132) correlated with the Cu and Ni concentration of bark plus phloem. Isolates of the most common endophytic taxa and the pathogenic Gremmeniella abietina from Harjavalta were grown in vitro in different levels of Cu (0.6 – 126 μg/mL) and Ni (0.3 – 50 μg/mL) separately and in combination. This experiment included also isolates of G. abietina and Hormonema sp. 1 from the northern (unpolluted) area. The concentrations of Cu and Ni that reduced the linear growth to 50% of control were estimated. The endophyte taxa with positively correlated frequency with increasing concentration of Cu and Ni in the shoots were able to withstand elevated levels of Cu and Ni in vitro. Compared with most of the other fungi, G. abietina isolates were particularly sensitive to addition of Ni. No evidence for intraspecific adaptation of G. abietina and Hormonema sp. 1 to Cu and Ni was found. Key words: endophyte, Gremmeniella, heavy metal, Hormonema, Scots pine.

An in vitro comparison of the ability of three commonly used pediatric cardiopulmonary bypass circuits to filter gaseous microemboli

Perfusion ◽  
2010 ◽  
Vol 25 (4) ◽  
pp. 255-263 ◽  
Author(s):  
Richard W Melchior ◽  
Tami Rosenthal ◽  
Andrew C Glatz
Keyword(s):  
Cardiopulmonary Bypass ◽  
In Vitro Model ◽  
The Other ◽  
Arterial Line ◽  
Independent Variables ◽  
Absolute Flow ◽  
In Vitro Investigation ◽  
Vitro Model ◽  
Different Levels

Background: The purpose of this study was to compare the ability of three commonly used pediatric cardiopulmonary bypass (CPB) circuits to filter gaseous microemboli (GME) in an in vitro model. Methods: Devices were tested at different levels of two specific independent variables: volume of air injected (1, 3, 5ml) and percentage of each oxygenator’s rated flow (50%, 75%, 100%, 125%). The air-handling ability of each CPB circuit was determined by the Emboli Detection and Classification Quantifier (Luna Innovations Inc., Roanoke,VA). Results: At all tested conditions, the FX-05 allowed a higher percentage of GME when compared to either one or both of the other two CPB circuits. When comparing oxygenators at similar absolute flow rates, the KIDS D100/D130 CPB circuit performed worse compared to the other two CPB circuits. C onclusions: The combination of the Baby RX-05 oxygenator and Capiox AF02 arterial line filter provides the highest level of protection from air emboli in an in vitro investigation.

scholarly journals The structure and reactivity of the HoxEFU complex from the cyanobacterium Synechocystis sp. PCC 6803

2020 ◽  
Vol 295 (28) ◽  
pp. 9445-9454
Author(s):  
Jacob H. Artz ◽  
Monika Tokmina-Lukaszewska ◽  
David W. Mulder ◽  
Carolyn E. Lubner ◽  
Kirstin Gutekunst ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Electron Flow ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Cellular Components ◽  
Electron Carriers ◽  
Electron Paramagnetic ◽  
Photosynthetic Electron Transfer

Cyanobacterial Hox is a [NiFe] hydrogenase that consists of the hydrogen (H2)-activating subunits HoxYH, which form a complex with the HoxEFU assembly to mediate reactions with soluble electron carriers like NAD(P)H and ferredoxin (Fdx), thereby coupling photosynthetic electron transfer to energy-transforming catalytic reactions. Researchers studying the HoxEFUYH complex have observed that HoxEFU can be isolated independently of HoxYH, leading to the hypothesis that HoxEFU is a distinct functional subcomplex rather than an artifact of Hox complex isolation. Moreover, outstanding questions about the reactivity of Hox with natural substrates and the site(s) of substrate interactions and coupling of H2, NAD(P)H, and Fdx remain to be resolved. To address these questions, here we analyzed recombinantly produced HoxEFU by electron paramagnetic resonance spectroscopy and kinetic assays with natural substrates. The purified HoxEFU subcomplex catalyzed electron transfer reactions among NAD(P)H, flavodoxin, and several ferredoxins, thus functioning in vitro as a shuttle among different cyanobacterial pools of reducing equivalents. Both Fdx1-dependent reductions of NAD+ and NADP+ were cooperative. HoxEFU also catalyzed the flavodoxin-dependent reduction of NAD(P)+, Fdx2-dependent oxidation of NADH and Fdx4- and Fdx11-dependent reduction of NAD+. MS-based mapping identified an Fdx1-binding site at the junction of HoxE and HoxF, adjacent to iron-sulfur (FeS) clusters in both subunits. Overall, the reactivity of HoxEFU observed here suggests that it functions in managing peripheral electron flow from photosynthetic electron transfer, findings that reveal detailed insights into how ubiquitous cellular components may be used to allocate energy flow into specific bioenergetic products.

scholarly journals Reconstitution of three-phase microtubule polymerisation dynamics

2016 ◽  
Author(s):  
Takashi Moriwaki ◽  
Gohta Goshima
Keyword(s):  
Growth Rate ◽  
Dynamic Instability ◽  
Molecular Level ◽  
The Other ◽  
Mitotic Kinase ◽  
The Core ◽  
Three Phase ◽  
Cytoplasmic Microtubules ◽  
Mitotic Cells

Cytoplasmic microtubules (MTs) undergo growth, shrinkage, and pausing. However, how MT polymerisation cycles are produced and spatiotemporally regulated at a molecular level is unclear, as the entire cycle has not been recapitulated in vitro with defined components. In this study, we reconstituted dynamic MT plus end behaviour involving all three phases, by mixing tubulin with five Drosophila proteins, EB1, XMAP215Msps, Sentin, kinesin-13Klp10A, and CLASPMast/Orbit. When singly mixed with tubulin, CLASPMast/Orbit strongly inhibited MT catastrophe and reduced the growth rate. However, in the presence of the other four factors, CLASPMast/Orbit acted as an inducer of pausing. The mitotic kinase Plk1Polo modulated the activity of CLASPMast/Orbit and kinesin-13Klp10A, and increased the dynamic instability of MTs, reminiscent of mitotic cells. These results suggest that five conserved proteins constitute the core factors for creating dynamic MTs in cells, and that Plk1-dependent phosphorylation is a crucial event for switching from the interphase to mitotic mode.

scholarly journals Five factors can reconstitute all three phases of microtubule polymerization dynamics

2016 ◽  
Vol 215 (3) ◽  
pp. 357-368 ◽  
Author(s):  
Takashi Moriwaki ◽  
Gohta Goshima
Keyword(s):  
Dynamic Instability ◽  
Molecular Level ◽  
The Other ◽  
Mitotic Kinase ◽  
The Core ◽  
Microtubule Polymerization ◽  
Five Factors ◽  
Cytoplasmic Microtubules ◽  
Three Phases

Cytoplasmic microtubules (MTs) undergo growth, shrinkage, and pausing. However, how MT polymerization cycles are produced and spatiotemporally regulated at a molecular level is unclear, as the entire cycle has not been recapitulated in vitro with defined components. In this study, we reconstituted dynamic MT plus end behavior involving all three phases by mixing tubulin with five Drosophila melanogaster proteins (EB1, XMAP215Msps, Sentin, kinesin-13Klp10A, and CLASPMast/Orbit). When singly mixed with tubulin, CLASPMast/Orbit strongly inhibited MT catastrophe and reduced the growth rate. However, in the presence of the other four factors, CLASPMast/Orbit acted as an inducer of pausing. The mitotic kinase Plk1Polo modulated the activity of CLASPMast/Orbit and kinesin-13Klp10A and increased the dynamic instability of MTs, reminiscent of mitotic cells. These results suggest that five conserved proteins constitute the core factors for creating dynamic MTs in cells and that Plk1-dependent phosphorylation is a crucial event for switching from the interphase to mitotic mode.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

ALDOSTERONE STIMULATION IN VITRO

1965 ◽  
Vol 50 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Jürg Müller
Keyword(s):  
Ammonium Chloride ◽  
Human Urine ◽  
Incubation Medium ◽  
The Other ◽  
Ammonium Ions ◽  
Response Curves ◽  
Urine Extract ◽  
Similar Dose ◽  
Aldosterone Production

ABSTRACT An extract of human urine, which was previously shown to stimulate aldosterone production by rat adrenal sections, was further purified. Evidence was obtained that its aldosterone-stimulating effect was due to the presence of ammonium ions. Addition of ammonium chloride and of urine extract to the incubation medium caused identical increases in aldosterone production in vitro. In addition to ammonium ions, rubidium and caesium ions also stimulated aldosterone production up to 250% that of control values without a significant effect on corticosterone production. Similar dose-response curves were obtained when increasing concentrations of potassium, ammonium, rubidium and caesium ions were tested. Aldosterone production was maximal at concentrations of 7 mval/1 and was significantly lower at higher concentrations. When ammonium chloride and ACTH were simultaneously added to the incubation medium, the production of aldosterone and of corticosterone was lower than with ACTH alone. On the other hand, the stimulating activity on aldosterone and corticosterone production by »TPN« (NADP) and glucose-6-phosphate was enhanced by the simultaneous addition of ammonium chloride.

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