scholarly journals ELECTRICAL CONTROL OF RHIZOID FORMATION IN THE RED ALGA, GRIFFITHSIA BORNETIANA

1934 ◽  
Vol 18 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Victor Schechter
Keyword(s):  
Red Alga ◽  
Ph Change ◽  
Electrical Field ◽  
Galvanic Current ◽  
Electrical Control ◽  
Differentiated Cells ◽  
Cytoplasmic Bodies ◽  
Bright Pink ◽  
Rhizoid Formation

1. Direct galvanic current of 10 to 40 microamperes per square millimeter of cross-section of medium results in anodal determination of rhizoid origin in the differentiated cells of the red alga Griffithsia bornetiana. The current is most effective near the upper end of the range. 2. Within the range used there is an increase in the number of rhizoids produced with increase in current intensity and a decrease in size of rhizoids. 3. Currents of lower intensity require a longer time to produce these effects than comparatively high currents. 4. The orientation of the plants in the electrical field seems to affect the number of rhizoids produced, in that plants with apexes toward the anode produce more rhizoids. 5. Together with anodal rhizoid determination there is migration of chromatophores toward the anodal side of each cell. 6. Displacement of chromatophores (and other cytoplasmic bodies) by the centrifuge does not affect the point of rhizoid origin, but does affect the shoots. 7. Together with anodal determination of rhizoids the algal filaments become graded in color, from bright pink toward the cathode to pale tan toward the anode. 8. Evidence is presented to show that this is not due to a pH change, but to a loss of pigment by chromatophores toward the anode and electrophoresis of the pigment toward the cathode. 9. In conclusion the probability is pointed out that the current acts in morphogenesis by moving particles of different charge.

scholarly journals Analysis of the Mycosporine-Like Amino Acid (MAA) Pattern of the Salt Marsh Red Alga Bostrychia scorpioides

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 321
Author(s):  
Maria Orfanoudaki ◽  
Anja Hartmann ◽  
Julia Mayr ◽  
Félix L. Figueroa ◽  
Julia Vega ◽  
...  
Keyword(s):  
Amino Acids ◽  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Red Alga ◽  
Array Detector ◽  
Diode Array ◽  
Diode Array Detector ◽  
The Past ◽  
Specific Species

This study presents the validation of a high-performance liquid chromatography diode array detector (HPLC-DAD) method for the determination of different mycosporine-like amino acids (MAAs) in the red alga Bostrychia scorpioides. The investigated MAAs, named bostrychines, have only been found in this specific species so far. The developed HPLC-DAD method was successfully applied for the quantification of the major MAAs in Bostrychia scorpioides extracts, collected from four different countries in Europe showing only minor differences between the investigated samples. In the past, several Bostrychia spp. have been reported to include cryptic species, and in some cases such as B. calliptera, B. simpliciuscula, and B. moritziana, the polyphyly was supported by differences in their MAA composition. The uniformity in the MAA composition of the investigated B. scorpioides samples is in agreement with the reported monophyly of this Bostrychia sp.

scholarly journals Pathophysiological In Vitro Profile of Neuronal Differentiated Cells Derived from Niemann-Pick Disease Type C2 Patient-Specific iPSCs Carrying the NPC2 Mutations c.58G>T/c.140G>T

2021 ◽  
Vol 22 (8) ◽  
pp. 4009
Author(s):  
Maik Liedtke ◽  
Christin Völkner ◽  
Alexandra V. Jürs ◽  
Franziska Peter ◽  
Michael Rabenstein ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transmembrane Protein ◽  
Hereditary Disease ◽  
Cholesterol Homeostasis ◽  
Patient Specific ◽  
Differentiated Cells ◽  
Npc1 Gene ◽  
Niemann Pick

Niemann-Pick type C2 (NP-C2) disease is a rare hereditary disease caused by mutations in the NPC2 gene. NPC2 is a small, soluble protein consisting of 151 amino acids, primarily expressed in late endosomes and lysosomes (LE/LY). Together with NPC1, a transmembrane protein found in these organelles, NPC2 accomplishes the exclusion of cholesterol; thus, both proteins are essential to maintain cellular cholesterol homeostasis. Consequently, mutations in the NPC2 or NPC1 gene result in pathophysiological accumulation of cholesterol and sphingolipids in LE/LY. The vast majority of Niemann-Pick type C disease patients, 95%, suffer from a mutation of NPC1, and only 5% display a mutation of NPC2. The biochemical phenotype of NP-C1 and NP-C2 appears to be indistinguishable, and both diseases share several commonalities in the clinical manifestation. Studies of the pathological mechanisms underlying NP-C2 are mostly based on NP-C2 animal models and NP-C2 patient-derived fibroblasts. Recently, we established induced pluripotent stem cells (iPSCs), derived from a donor carrying the NPC2 mutations c.58G>T/c.140G>T. Here, we present a profile of pathophysiological in vitro features, shared by NP-C1 and NP-C2, of neural differentiated cells obtained from the patient specific iPSCs. Profiling comprised a determination of the NPC2 protein level, detection of cholesterol accumulation by filipin staining, analysis of oxidative stress, and determination of autophagy. As expected, the NPC2-deficient cells displayed a significantly reduced amount of NPC2 protein, and, accordingly, we observed a significantly increased amount of cholesterol. Most notably, NPC2-deficient cells displayed only a slight increase of reactive oxygen species (ROS), suggesting that they do not suffer from oxidative stress and express catalase at a high level. As a site note, comparable NPC1-deficient cells suffer from a lack of catalase and display an increased level of ROS. In summary, this cell line provides a valuable tool to gain deeper understanding, not only of the pathogenic mechanism of NP-C2, but also of NP-C1.

III. An experimental determination of the velocity of sound

1872 ◽  
Vol 20 (130-138) ◽  
pp. 34-35
Keyword(s):  
Experimental Determination ◽  
Cape Town ◽  
The Other ◽  
Velocity Of Sound ◽  
Successful Operation ◽  
Single Wire ◽  
Galvanic Current ◽  
Royal Observatory ◽  
Port Elizabeth

A galvanic current passes from the batteries at the Royal Observatory, Cape Town, at 1 o’clock, and discharges a gun at the Castle, and through relays drops a time-ball at Port Elizabeth. It appeared to the author that a valuable determination of the velocity of sound might be obtained by measuring upon the chronograph of the Observatory the interval between the time of the sound reaching some point near the gun and that of its arrival at the Observatory. As there is only a single wire between the Observatory and Cape Town, some little difficulty was experienced in making the necessary arrangements, without any interference with the 1 o’clock current to Port Elizabeth; but this difficulty was overcome by a plan which the author describes, and which was brought into successful operation on Feb. 27, 1871. The experiments could not have been carried out, on account of the encroachment they would have made on the time of the Observatory staff, had it not been for the assistance of J. Den, Esq., the acting manager of the Cape Telegraph Company, to whom the author is indebted for the preparation of a good earth-connexion near the gun, for permission to Mr. Kirby, a gentleman attached to the telegraph office, to assist in the experiments, and for a general superintendence of the arrangements at Cape Town. The observed times of hearing the sound were recorded on the chronograph by two observers, situated one (Mr. Kirby) at a distance of 641 feet from the gun, the other (Mr. Mann) at the Observatory, at a distance of 15,449 feet from the gun. The former distance was sufficient to allow the connexion of the main wire to be broken at the telegraph office after the gun had been fired, but before the sound reached the first observer.

scholarly journals Conductimetric Biosensor for the Detection of Uric Acid by Immobilization Uricase on Nata de Coco Membrane—Pt Electrode

2011 ◽  
Vol 6 ◽  
pp. ACI.S7346 ◽  
Author(s):  
Ani Mulyasuryani ◽  
Arie Srihardiastutie
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Candida Utilis ◽  
Medical Laboratory ◽  
Membrane Thickness ◽  
Serum Samples ◽  
Ph Change ◽  
Pt Electrode ◽  
Enzyme Biosensor

A conductimetric enzyme biosensor for uric acid detection has been developed. The uricase, as enzyme, is isolated from Candida utilis and immobilized on a nata de coco membrane-Pt electrode. The biosensor demonstrates a linear response to urate over the concentration range 1-6 ppm and has good selectivity properties. The response is affected by the membrane thickness and pH change in the range 7.5-9.5. The response time is three minutes in aqueous solutions and in human serum samples. Application of the biosensor to the determination of uric acid in human serum gave results that compared favourably with those obtained by medical laboratory. The operational stability of the biosensor was not less than three days and the relative error is smaller than 10%.

Pattern formation in the Blue-Green Alga, Anabaena

1973 ◽  
Vol 12 (3) ◽  
pp. 707-723 ◽  
Author(s):  
MICHAEL WILCOX ◽  
G. J. MITCHISON ◽  
R. J. SMITH
Keyword(s):  
Pattern Formation ◽  
Green Alga ◽  
Normal Growth ◽  
Growth Conditions ◽  
Inhibitory Effect ◽  
Blue Green Alga ◽  
Interactive Model ◽  
Differentiated Cells ◽  
Sequence Of Events

Filaments of Anabaena have a spaced pattern of differentiated cells called heterocysts, which is maintained as a filament grows by the regular determination of new heterocysts. By following the growth of every cell in a filament, we have identified proheterocysts (prospective heterocysts) at their earliest appearance, and described the sequence of events in the formation of the pattern. The determination of proheterocysts obeys 2 rules: (1) that there are inhibitory zones around pre-existing heterocysts, and (2) that only the smaller daughter of a division can become a heterocyst (all divisions are asymmetrical). There are, however, certain conditions in which these rules are over-ridden, where a pattern consisting of groups of consecutive proheterocysts is seen which resolves into a normal discrete pattern. This process is highly suggestive of interaction between developing cells. We have tested this hypothesis in normal growth conditions by breaking filaments near to early proheterocysts, on the assumption that this will cause a build-up of inhibitory effect of the cell upon itself. It is found that these cells regress, losing their differentiated character and dividing. We therefore propose an interactive model for pattern formation in Anabaena.

FTIR-determination of sterols from the red alga Asparagopsis armata: Comparative studies with HPLC

Talanta ◽  
2006 ◽  
Vol 68 (4) ◽  
pp. 1230-1235 ◽  
Author(s):  
N ELHATTAB ◽  
Y DAGHBOUCHE ◽  
M HATTAB ◽  
L PIOVETTI ◽  
S GARRIGUES ◽  
...  
Keyword(s):  
Comparative Studies ◽  
Red Alga ◽  
Asparagopsis Armata

Tropical Marine Algae. VIII. The Structural Determination of Novel Sesquiterpenoid Metabolites From the Red Alga .Laurencia majuscula

1992 ◽  
Vol 45 (10) ◽  
pp. 1611 ◽  
Author(s):  
R Denys ◽  
JC Coll ◽  
BF Bowden
Keyword(s):  
Natural Products ◽  
Great Barrier Reef ◽  
Marine Algae ◽  
Structural Type ◽  
Red Alga ◽  
Structural Determination ◽  
Barrier Reef ◽  
Natural Products Chemistry ◽  
Laurencia Majuscula

An investigation of the natural products chemistry of the red alga Laurencia mujuscula from the Great Barrier Reef yielded three novel metabolites, (1), (2) and (3a), possessing a new sesquiterpenoid structural type. Known metabolites (6)-(11) were also isolated and the reassignment of n.m.r. spectral values for (11) is reported.

Determination of ionized calcium in serum that has been exposed to air.

1976 ◽  
Vol 22 (7) ◽  
pp. 1009-1011 ◽  
Author(s):  
D R Wybenga ◽  
F A Ibbott ◽  
D C Cannon
Keyword(s):  
Total Protein ◽  
Protein Concentration ◽  
Calcium Concentration ◽  
Electrode System ◽  
Ionized Calcium ◽  
Ph Change ◽  
Air Samples ◽  
Ph Values ◽  
Flow Through

Abstract We examined changes in ionized calcium concentration in serum after its exposure to air. Samples with total protein concentrations ranging from 50 to 90 g/liter were equilibrated with CO2 in nitrogen (5/95, by vol) or CO2 alone, to produce pH values of 7.0 to 8.0. Ionized calcium was then measured with an Orion flow-through electrode system. Curves relating pH and ionized calcium concentration had statistically identical slopes regardless of protein concentration. A factor was derived, based on pH change, for correcting values for ionized calcium in serum exposed to air, and its validity was confirmed by comparing corrected values for samples allowed to stand at ambient temperature (23 degrees C) without anaerobic precautions with values initially obtained on anaerobic aliquots of the same samples.

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