In situ H2 production and utilization by natural populations of N2-fixing blue-green algae

1982 ◽  
Vol 60 (12) ◽  
pp. 2542-2546 ◽  
Author(s):  
Hans W. Paerl

Contemporaneous in situ acetylene-reduction, 15N2-fixation, and 3H2-exchange assays reveal parallel patterns of N2 fixation and H2 utilization in natural populations of the blue-green algae Anabaena and Aphanizomenon. As spring and summer blooms progress, increasing ratios of acetylene reduction versus 15N2 fixation closely follow elevated rates of cellular H2 utilization. Both acetylene-reduction and H2-utilization rates were largely attributable to blue-green algae as opposed to associated bacteria and other phytoplankton. It is concluded that elevated H2 utilization reflects increased H2 production via nitrogenase. This can be substantiated by monitoring rising acetylene-reduction versus 15N2-fixation ratios during bloom development. Simultaneous deployment of the above techniques provides evidence for (a) in situ H2 production and (b) seasonal trends in rates of H2 production among natural blue-green algal populations.

2021 ◽  
Vol 9 (5) ◽  
pp. 543-571
Author(s):  
Ritu Chauhan ◽  
◽  
Abhishek Chauhan ◽  
Ashutosh Tripathi ◽  
Anuj Ranjan ◽  
...  

COVID-19 pandemic has taught the world researchers the urgent need for new sources and novel pharmaceuticals not only for existing diseases but also for both seasonal epidemics and future pandemics. Pharmaceutical drug discoveries for the past fifty years depended deeply on the procedure of empirical transmission of a huge number of pure bioactive compounds to provide new leads. The screening of extracts or isolating compounds is a common way to discover novel biologically active molecules. Most of the valuable Blue-Green algal metabolites are concentrated in their biomass. For existence in nature, Blue-Green algae (BGA) secrete and contain various organic substances like proteins, fatty acids, vitamins, pigments, primary and secondary metabolites, and these compounds are explored for potential biological activities such as antibacterial, antifungal, antiviral (including the anti-SARS-CoV-2 virus that causes COVID-19), anticancer, antioxidant, antidiabetic, protease inhibitory activity, anti-inflammatory activity, etc. Due to their diverse application, pharmaceutical companies have shown commercial interest in the Blue-green algal group for the discovery and development of novel molecules to combat deadly diseases for the benefit of society and mankind. The current review paper highlights and discusses the diverse pharmaceutical potential of laboratory-grown cultures of BGA along with comprehensive and current knowledge on bioactive compounds discovered by researchers globally.


1983 ◽  
Vol 15 (6-7) ◽  
pp. 181-190 ◽  
Author(s):  
George P Slater ◽  
Vivian C Blok

A relationship between blue-green algae and off-flavours in water was reported as early as 1883. Continuing research has shown that two metabolites, geosmin and methylisoborneol are major contributors to unpalatable flavours in water and aquatic organisms. Many instances of the co-occurrence of these two compounds and dense blooms of blue-green algae have been recorded. Cultures of Anabaena, Lyngbya, Osciiiatoria, and Sympioca species have been shown to produce geosmin or methylisoborneol while blooms of Aphanizomenon, Anabaena, Microcystis, Oscillatoria, and Gomphosphaeria have been found in water containing geosmin or the odour of this compound. Actinomycetes have also been shown to produce these two compounds. In addition to geosmin and methylisoborneol, there is evidence that several other blue-green algal metabolites contribute to aquatic taste and odour problems. Among them is β-cyclocitral which has a distinctive tobacco flavour. Blue-green algae produce a variety of organic compounds including hydrocarbons, fatty acids, aromatics, ketones, terpenoids, amines and Sulfides which could contribute to the over-all flavour of water and aquatic organisms.


1992 ◽  
Vol 49 (11) ◽  
pp. 2331-2336 ◽  
Author(s):  
D. J. Webb ◽  
B. K. Burnison ◽  
A. M. Trimbee ◽  
E. E. Prepas

Chlorophyll a (Chl a) in water samples from three mesotrophic to eutrophic lakes in north-central Alberta was extracted with one of three solvents (95% ethanol, 90% ethanol, or a 2:3 mixture of dimethyl sulfoxide and 90% acetone (DMSO/acetone)) and analyzed by two techniques (spectrophotometry and high pressure liquid chromatography (HPLC). The dominant phytoplankton were blue-green algae and diatoms. Total Chl a concentrations (i.e. no correction for phaeopigments (Pha)) were not significantly different among solvents (P > 0.5). Total Chl a concentrations from spectrophotometric analyses were significantly higher than those from HPLC analyses (4.2 ± 0.88 and 2.6 ± 0.50 μg∙L−1 respectively, P < 0.05). Pha concentrations derived by spectrophotometry were 64 times higher than those derived by HPLC (1.7 ± 0.52 and 0.025 ± 0.01 μg∙L−1 respectively, P < 0.005). Thus, spectrophotometry appears to dramatically overestimate Pha concentrations and may overestimate total Chl a (i.e. no correction for Pha). Therefore, ethanol and DMSO/acetone are equally suitable for Chl a extraction from natural populations dominated by blue-green algae and/or diatoms, but if information on Pha and/or accessory pigments is required, HPLC analyses are the appropriate route rather than spectrophotometry.


1986 ◽  
Vol 123 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Ruud Weijermars ◽  
Carla W. Mulder-Blanken ◽  
Jaap Wiegers

AbstractIn situ observations of fossil and living specimens of the calcicolous mosses Bryum pseudotriquetrum, Cratoneuron commutatum and Catoscopium nigritum revealed very fast calcite depositional rates. Rhythmic layering in the fossil mosses corresponding with the seasonal climatic cycle suggests that the moss curtain occupied by these three mosses maintains the deposition of spongeous travertine layers at a mean rate of 4 cm a−1. A mean depositional rate of 4.2 cm a−1 may be calculated from measurements of the loss of bicarbonate from the springwater after it percolated through the moss curtain. These rates suggest that the 8 m high travertine terrace of Checa with a surface area of 800 m2 did not exist two millennia ago.Mosses could be put to man's use for creating natural overgrowths on artificial surfaces, an idea based on an allusion by Wallner. He observed that the thread-forming, blue-green algae Vaucheria builds travertine deposits at an annual rate of 0.7–1.4 cm. We observed that the mosses Cratoneuron commutatum and Bryum pseudotriquetrum may form spongeous travertine layers at respective maximum rates of 11 and 14 cm a−1. This would reduce the time required to build natural overgrowths on artificial objects to a practical period of months.


1981 ◽  
Vol 38 (9) ◽  
pp. 1040-1044 ◽  
Author(s):  
T. P. Murphy ◽  
B. G. Brownlee

Within 24 h of an increase in lake [Formula: see text] concentration, [Formula: see text] uptake by Aphanizomenon flos-aquae and Microcystis aeruginosa increases much beyond the capacity predicted by Michaelis–Menten kinetic studies. In hypertrophic lakes this response enables these blue-green algae to optimize ammonia uptake during large oscillations of [Formula: see text] concentration, to aid them in competing with other algae, and to conserve [Formula: see text] within the ecosystem. Nitrogen limitation in the hypertrophic prairie lakes is a rare event.Key words: ammonia uptake, prairie lakes, nitrogen limitation, nitrogen cycle


2020 ◽  
Vol 26 (1) ◽  
Author(s):  
Ganesh S. Shinde

Blue-green algae make a valuable contribution to the nitrogenous soil fertility by fixing atmospheric nitrogen and are of great agricultural importance as biofertilizer. Four commercial grade pesticides, Carbamate, Furadan and Sevin and Organophosphate, Rogor and Organochlorine, Endotaf were used to study their effect on the survivability and qualitative occurrence of blue-green algae by taking survival on the control plate as 100%. Stock solutions of these pesticides were prepared freshly for experiments in the sterilized BG-11 media and added to the culture media to obtain the desired concentrations of 100, 250, 500 and 1000 ppm. After 30 days of incubation, the blue-green algal forms appeared in the culture flask were identified using standard monographs. The pragmatic results indicated that, soil blue-green algae show variable resistance to pesticide treatments. The survival percentage of the tested blue-green algae was reduced upto 50 percent at 500 ppm of carbamate pesticides, Furadan and Sevin. While with Rogor only 10.52% and Endotaf 5.26% survivability was noticed at 500 ppm dose level. Furthermore, the organochlorine pesticide Endotaf was more toxic than the organophosphate, Rogor and the carbamates, Sevin and Furadan in sequence to the blue-green algae. It was cocluded that higher doses of pesticide application in the crop fields i.e. more than 100 ppm of Furadan, Sevin and Rogor and even at 100 ppm of Endotaf, qualitative and quantitative occurrence of heterocystous and non- heterocystous blue-green algae was decreased considerably. This suggests that, indiscriminate use of these pesticides may cause adverse effects on the nitrogen fixing blue-green algae of various crop fields, which has a direct influence on total productivity. In general, the sensitiveness of different blue-green algae to pesticide application was found to be more in sheathless heterocystous and unicellular forms than the heterocystous ensheathed and non- heterocystous ensheathed forms.


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