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.

External Factors Influencing Light-Induced Hydrogen Evolution by the Blue-Green Alga, Nostoc muscorum

1979 ◽  
Vol 34 (9-10) ◽  
pp. 820-825 ◽  
Author(s):  
Anneliese Ernst ◽  
Wolfgang Kerfin ◽  
Hartmut Spiller ◽  
Peter Böger
Keyword(s):  
Hydrogen Evolution ◽  
Green Alga ◽  
Growth Conditions ◽  
External Factors ◽  
Molar Ratio ◽  
Nostoc Muscorum ◽  
Hydrogenase Activity ◽  
Blue Green Alga ◽  
Intact Cells ◽  
Temperature Ageing

Abstract This study was conducted to determine some physiological conditions which influence light-in­duced hydrogen evolution by intact cells of the blue-green alga Nostoc muscorum. This activity was found to be dependent on the age of the culture, cultivation temperature, ageing of the cells, and on gassing the cultures with nitrogen or air. Nitrogenase is particularly active after cultivation at 22 °C but not at 32 °C although growth is about the same. The molar ratio of acetylene reduction to hydrogen evolution -both gas exchanges obviously catalyzed by nitrogenase - is also dependent on age and temperature of the culture. A hydrogen-consuming (“up­ take”) hydrogenase activity is present and affected by prolonged microaerobic, but not by aerobic growth conditions, and stimulated by light. External factors during growth apparently influence differently the activities of nitrogenase and uptake hydrogenase. Consequently -besides the electron donor supply -net light-induced hydro­ gen evolution by intact cells is dependent on these two variable activities.

Aminotransferase-Aktivität in der Blaualge Anacystis nidulans / Activity of Aminotransferases in the Blue Green Alga Anacystis nidulans

1976 ◽  
Vol 31 (7-8) ◽  
pp. 433-435 ◽  
Author(s):  
Günter Döhler
Keyword(s):  
Green Alga ◽  
Alanine Aminotransferase ◽  
Control Experiment ◽  
Inhibitory Effect ◽  
Anacystis Nidulans ◽  
Blue Green Alga ◽  
Aminotransferase Activity ◽  
14C Labelling ◽  
Isonicotinyl Hydrazide ◽  
Alanine Aminotransferase Activity

Abstract The blue-green alga Anacystis nidulans (strain L 1402-1) was grown at + 37 °C in air (0.03 vol.% CO2 and in air enriched with 3.0 vol.% CO2. The effects of several inhibitors on the activity of aminotransferases, 14CO2 fixation and radioactive photosynthetic products of Anacystis were studied. No serine-pyruvate aminotransferase activity could be found in 10-2 м isonicotinyl hydrazide (INH) ; under the influence of this inhibitor aspartate and alanine aminotransferase were decreased about 49% respectively 17.6%. Serine-pyruvate and alanine aminotransferase activity decreased to more than 50% in 10-3 м glyoxalbisulfite. The obtained inhibitory effect of 10-4 м HPMS on serine-piruvate aminotransferase (35%) was stronger than on the other aminotransferases. DCMU (5 × 10-6 м) inhibition on alanine aminotransferase activity was 83.7%. Under the influence of 10-3 м glyoxalbisulfite no 14C-labelled amino acids could be detected after 5 min photosynthesis; 14C-labelling of phosphoenolpyruvate, malate, phosphoglycolate and glycolic acid increased. Isonicotinyl hydrazide (10-2 м) caused in comparison to the control experiment a lower radioactivity in aspartate, glutamate and phosphoenolpyruvate. The results are discussed with reference to the operation of the glycolate pathway and a carboxylation reaction of phosphoenolpyruvate in the blue-green alga Anacystis nidulans.

Stickstoff-Ausscheidung durch N 2-fixierende Blaualgen, III / Nitrogen Excretion by Nitrogen Fixing Blue-green Algae, III

1975 ◽  
Vol 30 (3-4) ◽  
pp. 223-226 ◽  
Author(s):  
P. Pohl ◽  
G. Rath
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
Growth Conditions ◽  
Nitrogen Excretion ◽  
Blue Green Alga ◽  
Nitrogen Fixing ◽  
Blue Green Algae ◽  
Combined Nitrogen ◽  
Nitrogen Levels ◽  
Filamentous Green Algae

Abstract The total combined nitrogen (850 //mol N/1) excreted by the nitrogen fixing blue-green alga, A nabaena cylin drica, during growth in an artificial nutrient medium, was subsequently utilized to a different degree by various green algae. Two species of filamentous green algae, Chlorhormidium spec, (strain I) and Chlorhorm idium spec, (strain II), proved to be most suitable: When grown in the above nitrogen-enriched medium after removal of A nabaena cylindrica, they lowered the nitrogen level in the medium from 850 to 460 - 600//mol N/1 within 29 days. When another nitrogen fixing blue-green alga, Anabaena solitaria, was grown under unsterile conditions in mixtures of freshwater and seawater with trace elements (Fe, Mn, and Mo) added, nitrogen levels of 1000 - 1060 //mol N/1 were obtained. These levels were subsequently lowered to 530 - 570 //mol N/1 by the two species of Chlorhorm idium . Under appropriate growth conditions, the combined nitrogen excreted by Anabaena solitaria can possibly be utilized as a nitrogen source for green algae

Pattern Formation in the Blue-Green Alga Anabaena

1973 ◽  
Vol 13 (3) ◽  
pp. 637-649
Author(s):  
MICHAEL WILCOX ◽  
G. J. MITCHISON ◽  
R. J. SMITH
Keyword(s):  
Pattern Formation ◽  
Green Alga ◽  
Developmental Stages ◽  
Blue Green Alga ◽  
Inhibitory Substance ◽  
Vegetative Cells ◽  
Stage Of Development ◽  
Competitive Mechanism

We present further evidence for an interactive mechanism in the formation of the spaced pattern of heterocysts in Anabaena. The evidence comes from experiments which are an extension of those described earlier, in which filaments of the alga are broken near to a proheterocyst. We argue that a proheterocyst depends upon neighbouring vegetative cells for the removal of an inhibitory substance: when the proheterocyst is deprived of these supporting vegetative cells it will be forced to regress. We showed earlier that such regressions do occur in early proheterocysts when a filament is broken on one side only. We now find that advanced pro-heterocysts can be made to regress when double breakages are performed to leave small fragments containing the proheterocysts. The probability of a proheterocyst regressing is correlated with its stage of development and with the size of the fragment: the smaller the fragment, the more advanced is the stage at which regression will occur. To formulate this we have defined developmental stages in terms of ultrastructure and compiled the results of a diversity of breakage operations with the cells at these specified stages. Certain compounds affect the spacing of the heterocyst pattern, causing it to become wider or narrower. These compounds have the predicted effect upon regression frequencies, up-holding our assumption that regressions express an underlying competitive mechanism.

scholarly journals Potential of Sorghum bicolor L. (Moench) and the Effect of Enhancements in Remediation of Petroleum-Vitiated Soils of an Automobile Repair Workshop in Urbanite Kampala

2019 ◽  
Author(s):  
Timothy Omara ◽  
Raymond Kalukusu ◽  
Eddie Adupa ◽  
Tom Owori ◽  
David Mawanda Kizza ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Contaminated Soils ◽  
Normal Growth ◽  
Growth Conditions ◽  
Cow Dung ◽  
Npk Fertilizer ◽  
Sorghum Bicolor L ◽  
Petroleum Oil

The potential of Sorghum bicolor L. (Moench) (Epuripur 1995) to phytoremediate petroleum oil-adulterated soils from an automobile repair workshop and the effect of enhancement factors: NPK fertilizer, cow dung and sewage sludge in in situ phytoremediation of the soil by the plant were assessed in this study. 50kg of petroleum oil-contaminated soil was collected from the workshop and divided into five equal portions. Four portions were potted with four sorghum plants with three subjected to equal amounts of enhancements (5%w/w) under normal growth conditions for 72 days. Representative soil samples were collected from spots at depths of 0–10 cm and 10–20 cm from the potted soils and subjected to Soxhlet oil extraction after 72 days. Experimental results revealed that S. bicolor survived in the petroleum oil-contaminated soils. Amendment of the petroleum oil-vitiated soils with cow dung, sewage sludge and NPK fertilizer augmented the remediation capacity of Epuripur 1995 by 12.5%, 6.3% and 9.1%. Addition of cow dung to crude oil contaminated soils could make such soils fully reestablished for agricultural activities. Further research aimed at determination of the phytoremediation potential of cereals such as corn, barley, rye, millet should be done.

Studies on the Fluorometric Determination of the Toxins of the Blue-green Alga Aphanizomenon Flos-Aquae

1981 ◽  
pp. 415-425
Author(s):  
Miyoshi Ikawa ◽  
Karin Wegener ◽  
Thomas L. Foxall ◽  
John J. Sasner ◽  
Philip W. Carter ◽  
...  
Keyword(s):  
Green Alga ◽  
Blue Green Alga ◽  
Fluorometric Determination

scholarly journals Investigation and Rapid Discrimination of Food-Related Bacteria under Stress Treatments Using IR Microspectroscopy

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1850
Author(s):  
Daniel Klein ◽  
René Breuch ◽  
Jessica Reinmüller ◽  
Carsten Engelhard ◽  
Peter Kaul
Keyword(s):  
Stress Responses ◽  
Rapid Determination ◽  
Protein Secondary Structure ◽  
Normal Growth ◽  
Growth Conditions ◽  
Stress Conditions ◽  
Regular Treatment ◽  
Ir Microspectroscopy ◽  
Rapid Discrimination

Because the robust and rapid determination of spoilage microorganisms is becoming increasingly important in industry, the use of IR microspectroscopy, and the establishment of robust and versatile chemometric models for data processing and classification, is gaining importance. To further improve the chemometric models, bacterial stress responses were induced, to study the effect on the IR spectra and to improve the chemometric model. Thus, in this work, nine important food-relevant microorganisms were subjected to eight stress conditions, besides the regular culturing as a reference. Spectral changes compared to normal growth conditions without stressors were found in the spectral regions of 900–1500 cm−1 and 1500–1700 cm−1. These differences might stem from changes in the protein secondary structure, exopolymer production, and concentration of nucleic acids, lipids, and polysaccharides. As a result, a model for the discrimination of the studied microorganisms at the genus, species and strain level was established, with an accuracy of 96.6%. This was achieved despite the inclusion of various stress conditions and times after incubation of the bacteria. In addition, a model was developed for each individual microorganism, to separate each stress condition or regular treatment with 100% accuracy.

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