Effect of light intensity on the ultrastructure of the filamentous cyanobacterium, Anabaena variabilis

Author(s):  
C. S. Bricker ◽  
S. R. Barnum ◽  
B. Huang ◽  
J. G. Jaworskl

Cyanobacteria are Gram negative prokaryotes that are capable of oxygenic photosynthesis. Although there are many similarities between eukaryotes and cyanobacteria in electron transfer and phosphorylation during photosynthesis, there are two features of the photosynthetic apparatus in cyanobacteria which distinguishes them from plants. Cyanobacteria contain phycobiliproteins organized in phycobilisomes on the surface of photosynthetic membrane. Another difference is in the organization of the photosynthetic membranes. Instead of stacked thylakolds within a chloroplast envelope membrane, as seen In eukaryotes, IntracytopIasmlc membranes generally are arranged in three to six concentric layers. Environmental factors such as temperature, nutrition and light fluency can significantly affect the physiology and morphology of cells. The effect of light Intensity shifts on the ultrastructure of Internal membrane in Anabaena variabilis grown under controlled environmental conditions was examined. Since a major constituent of cyanobacterial thylakolds are lipids, the fatty acid content also was measured and correlated with uItrastructural changes. The regulation of fatty acid synthesis in cyanobacteria ultimately can be studied if the fatty acid content can be manipulated.

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Jean Claude Nzayisenga ◽  
Xavier Farge ◽  
Sophia Leticia Groll ◽  
Anita Sellstedt

Abstract Background Cultivation of microalgae in wastewater could significantly contribute to wastewater treatment, biodiesel production, and thus the transition to renewable energy. However, more information on effects of environmental factors, including light intensity, on their growth and composition (particularly fatty acid contents) is required. Therefore, we investigated the biomass and fatty acid production of four microalgal species, isolated in the Northern hemisphere and grown at three light intensities (50, 150 and 300 μE m−2 s−1). Results Increases in light intensities resulted in higher biomass of all four species and, importantly, raised fatty acid contents of both Desmodesmus sp. and Scenedesmus obliquus. Fourier-transform IR spectrometry analysis showed that the increases in fatty acid content were associated with reductions in protein, but not carbohydrate, contents. Assessment of fatty acid composition revealed that increasing light intensity led to higher and lower contents of oleic (18:1) and linolenic (18:3) acids, respectively. The microalgae consumed more than 75% of the nitrogen and phosphorus present in the wastewater used as growth medium. Conclusion The results show the importance of optimizing light intensities to improve fatty acid production by microalgae and their quality as sources of biodiesel. In addition, increase in fatty acid content is associated with decrease in protein content.


2016 ◽  
Vol 2 (1) ◽  
pp. 37-42 ◽  
Author(s):  
J.M. Pino Moreno ◽  
A. Ganguly

In the present paper we have determined the fatty acid content of some edible insects of Mexico. A comparative analysis of the insect species studied in this research showed that caproic acid was present in a minimal proportion which ranged between 0.01 for Periplaneta americana (nymphs) and 0.06 (g/100 g, dry basis) for Euschistus strenuus. The highest proportion of caprilic acid (0.09) was found in Tenebrio molitor (adults). Atta sp. had the highest amount of capric acid (0.26). Polistes sp. was found to be rich in lauric acid (0.77) and for myristic acid it had the highest content (5.64). Dactylopius sp. and E. strenuus were rich in palmitic acid (14.89). Euschistus taxcoensis had the highest quantity of palmitoleic acid (12.06). Llaveia axin exhibited the highest quantity of stearic acid (22.75). Polistes sp. was found to be rich in oleic acid (38.28). The highest quantity of linoleic acid was observed in T. molitor (larvae) (10.89), and in L. axin the highest content of linolenic acid (7.82) was obtained. A comparison between the species under the present investigation revealed that, in general, the insects are poor in caproic, caprilic, capric, lauric, myristic, palmitoleic and linolenic acids, because the quantities were either minimal or could not be detected at all. They had moderate quantities of stearic, palmitic and linoleic acids and had high quantities of oleic acid. Finally it was concluded that although a particular insect species is unable to fulfil the total fatty acid need for a human, if consumed in combination they could definitely be able to supply a good amount of this highly valued nutrient.


Diversity ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 105
Author(s):  
Amirah Yuslan ◽  
Sharifah Najuwa ◽  
Atsushi Hagiwara ◽  
Mazlan A. Ghaffar ◽  
Hidayu Suhaimi ◽  
...  

Salinity is a known factor in shaping population dynamics and community structure through direct and indirect effects on aquatic ecosystems. Salinity changes further influence food webs through competition and predation. The responses of Moina macrocopa (Cladocera) collected from Setiu Wetland lagoon (Terengganu) was evaluated through manipulative laboratory experiments to understand the ability of M. macrocopa to tolerate high salinity stress. Specifically, the fatty acid composition, growth, survival, and reproduction of this cladocerans species was examined. Sodium chloride (NaCl) as used in the treatments water with the concentration 0, 4, 6, 8, 12, and 15 salinity. Fatty acid levels were determined using Gas Chromatography and Mass Spectrophotometry (GC-MS). The results indicated that optimal conditions produced the highest fatty acid content, especially the polyunsaturated fatty acid content, such as EPA (eicosapentaenoic acid), ALA (alpha-linoleic acid), ARA (arachidonic acid), and DHA (docosahexaenoic acid). Furthermore, M. macrocopa survival was best at salinity 0, with a percentage of 98%, whereas the opposite occurred at salinity 15, with approximately 20% of viable animals surviving. Besides, M. macrocopa also showed the highest reproduction rate at salinity 0 (e.g., average initial age of reproduction, 4.33 ± 0.58 days) compared with other salinities level. Interestingly, the difference in growth at different salinities was not evident, an unusual finding when considering adverse effects such as osmoregulation pressure on the organism. Based on the results, we conclude that M. macrocopa can only tolerate salinity below salinity 8 and cannot withstand stressful environmental conditions associated with salinities above 8.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Roel M. Maas ◽  
Yale Deng ◽  
Yueming Dersjant-Li ◽  
Jules Petit ◽  
Marc C. J. Verdegem ◽  
...  

AbstractSustainable aquafeed production requires fishmeal replacement, leading to an increasing use of plant-derived ingredients. As a consequence, higher levels of antinutritional substances, such as non-starch polysaccharides and phytate, are present in aquafeeds, with negative effects on fish performance, nutrient digestibility and overall gut health. To alleviate these negative effects, providing exogenous digestive enzymes and/or probiotics can be an effective solution. In this study, we tested the effect of dietary supplementation of enzymes (phytase and xylanase) and probiotics (three strains of Bacillus amyloliquefaciens) on nutrient digestion kinetics and volatile fatty acid content along the gut, and the distal gut microbiome diversity in Nile tilapia. Chyme volatile fatty content was increased with probiotic supplementation in the proximal gut, while lactate content, measured for the first time in vivo in fish, decreased with enzymes along the gut. Enzyme supplementation enhanced crude protein, Ca and P digestibility in proximal and middle gut. Enzymes and probiotics supplementation enhanced microbial interactions as shown by network analysis, while increased the abundance of lactic acid bacteria and Bacillus species. Such results suggest that supplementation with exogenous enzymes and probiotics increases nutrient availability, while at the same time benefits gut health and contributes to a more stable microbiome environment.


2020 ◽  
Vol 11 (1) ◽  
pp. 188
Author(s):  
Piotr Skałecki ◽  
Agnieszka Kaliniak-Dziura ◽  
Piotr Domaradzki ◽  
Mariusz Florek ◽  
Ewa Poleszak ◽  
...  

The aim of the study was to assess the influence of the addition of fish raw materials (roe or fish meat) on the quality and nutritional value of pork pâtés. The control group (n = 4) consisted of pork pâtés, I experimental group (n = 6) of pâtés with 20% addition of roe (perch and pike), and II group of pâtés with 20% addition of fish (perch and pike meat) (n = 6). The pâtés’ pH, color, and profiled texture analysis were instrumentally measured and water, protein, fat, ash, and fatty acid content were determined by reference methods. To assess the oxidative stability of lipids the measurement of peroxide number, thiobarbituric acid reactive substances and content of conjugated dienes and trienes was used. The degree of fat hydrolysis was determined on the basis of acid value. Sensory analysis was carried out using the scaling method, taking into account 12 unit quality characteristics. Products with roe and meat contained less fat (accordingly 15.9% and 14.1%) and showed lower calorific value (accordingly 225.6 and 208.6 kcal/100 g) compared to pork pâtés (20.2% of lipids, 267 kcal/100 g). Moreover, the addition of fish raw materials improved the index of nutritional quality for protein (from 3.2 to 3.9) and beneficially reduced the nutritional index for fat (from 2.2 to 1.9). Fish constituents modified, to a certain extent, the color, texture, and sensory properties of pâtés, while maintaining full acceptability in consumer assessment. The addition of fish roe significantly increased the healthful quality by improving the fatty acid profile of pâtés, in which the significantly highest content of n-3 fatty acids, including eicosapentaenoic and docosahexaenoic acids (accordingly 252.21, 43.17, and 107.94 mg/100 g product), as well the highest concentration of saturated branched chain fatty acids were determined (18.75 mg/100 g product).


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