Impact of growth medium salinity on galactoxylan exopolysaccharides of Porphyridium purpureum

2021 ◽  
Vol 59 ◽  
pp. 102439
Author(s):  
Andreia S. Ferreira ◽  
Inês Mendonça ◽  
Inês Póvoa ◽  
Hélia Carvalho ◽  
Alexandra Correia ◽  
...  
Keyword(s):  
Growth Medium ◽  
Porphyridium Purpureum

Ultrastructural Alterations in Hela Cells Induced by Spider Venom

1967 ◽  
Vol 25 ◽  
pp. 20-21
Author(s):  
Dale E. McClendon ◽  
Paul N. Morgan ◽  
Bernard L. Soloff
Keyword(s):  
Growth Medium ◽  
Mammalian Cells ◽  
Carcinoma Cells ◽  
Venom Protein ◽  
Sterile Saline ◽  
Carbon Coated ◽  
Available Information ◽  
Loxosceles Reclusa ◽  
Essential Growth ◽  
Solution Cultures

It has been observed that minute amounts of venom from the brown recluse spider, Loxosceles reclusa, are capable of producing cytotoxic changes in cultures of certain mammalian cells (Morgan and Felton, 1965). Since there is little available information concerning the effect of venoms on susceptible cells, we have attempted to characterize, at the electron microscope level, the cytotoxic changes produced by the venom of this spider.Cultures of human epithelial carcinoma cells, strain HeLa, were initiated on sterile, carbon coated coverslips contained in Leighton tubes. Each culture was seeded with approximately 1x105 cells contained in 1.5 ml of a modified Eagle's minimum essential growth medium prepared in Hank's balanced salt solution. Cultures were incubated at 36° C. for three days prior to the addition of venom. The venom was collected from female brown recluse spiders and diluted in sterile saline. Protein determinations on the venom-were made according to the spectrophotometric method of Waddell (1956). Approximately 10 μg venom protein per ml of fresh medium was added to each culture after discarding the old growth medium. Control cultures were treated similarly, except that no venom was added. All cultures were reincubated at 36° C.

Effect of Iron Limitation on the Ultrastructure of Agmenellum Quadruplicatum

1981 ◽  
Vol 39 ◽  
pp. 410-411
Author(s):  
L. P. Hardie ◽  
D. L. Balkwill ◽  
S. E. Stevens
Keyword(s):  
Growth Medium ◽  
Green Alga ◽  
Natural Habitat ◽  
Iron Limitation ◽  
Natural Environments ◽  
Blue Green Alga ◽  
Marine Cyanobacterium ◽  
Natural Systems ◽  
Thin Sectioning ◽  
Agmenellum Quadruplicatum

Agmenellum quadruplicatum is a unicellular, non-nitrogen-fixing, marine cyanobacterium (blue-green alga). The ultrastructure of this organism, when grown in the laboratory with all necessary nutrients, has been characterized thoroughly. In contrast, little is known of its ultrastructure in the specific nutrient-limiting conditions typical of its natural habitat. Iron is one of the nutrients likely to limit this organism in such natural environments. It is also of great importance metabolically, being required for both photosynthesis and assimilation of nitrate. The purpose of this study was to assess the effects (if any) of iron limitation on the ultrastructure of A. quadruplicatum. It was part of a broader endeavor to elucidate the ultrastructure of cyanobacteria in natural systemsActively growing cells were placed in a growth medium containing 1% of its usual iron. The cultures were then sampled periodically for 10 days and prepared for thin sectioning TEM to assess the effects of iron limitation.

Cultivation and Harvesting of Selenium-Enriched Ganoderma lingzhi and Spent Medium Using Kudzu Vine as Substrate

2019 ◽  
Vol 18 (2) ◽  
pp. 152-157
Author(s):  
Zeng Xianlu ◽  
Han Fei ◽  
Zhong Yanmei
Keyword(s):  
Growth Medium ◽  
Wheat Bran ◽  
Fruiting Body ◽  
Sodium Selenite ◽  
Human Consumption ◽  
Growth Substrate ◽  
Organic Selenium ◽  
Significant Difference ◽  
Ganoderma Lingzhi ◽  
Run Speed

In order to harvest selenium-enriched fruiting body and spores of Ganoderma lingzhi and spent medium, G. lingzhi was cultivated in kudzu vine as substrate and the bio-transformation of selenite was evaluated. The growth medium consisted of Kudzu vine supplemented with 20% wheat bran or sawdust or none. The growth medium was supplemented with 0, 10, 20, 30, and 50 mg/kg of sodium selenite. We found a significant difference in spawn run speed, fruiting body and spore yields when Kudzu vine was supplemented with wheat bran or sawdust. However, when whole-kudzu vine was used alone as substrate, it resulted in a significantly lower spawn run speed, fruiting body, and spore yields compared with kudzu vine + sawdust substrate and kudzu vine + wheat bran substrate. The selenium content in fruiting body and spores increased with increasing sodium selenite supplementation and approximately equaled half of the selenium in the substrate. No selenite was detected in both the fruiting body and spores. However, in the spent medium when sodium selenite was supplemented at 10, 20, 30, 50 mg/kg, the residual selenite concentration decreased to 0.45, 0.72, 1.29, and 1.95 mg/kg, respectively, suggesting a higher selenite transformation (92.27–93.57%). In conclusion, if Ganoderma fruiting body and spores were to be harvested for human consumption, approximately 50 mg/kg selenite should be added to the growth substrate. On the other hand, if the spent medium was to be used as an organic selenium source, the optimal sodium selenite supplementation level would be 10 mg/kg.

Selenium Uptake by a Coal Mine Wetland Sediment

2003 ◽  
Vol 38 (3) ◽  
pp. 483-497 ◽  
Author(s):  
Susan A. Baldwin ◽  
Al Henry Hodaly
Keyword(s):  
Growth Medium ◽  
Coal Mine ◽  
Mine Waste ◽  
Reduction Rate ◽  
Plant Debris ◽  
Bacteria Growth ◽  
Sulfate Reducing ◽  
Selenium Uptake ◽  
Negative Effect ◽  
Reducing Bacteria

Abstract Sediment from a wetland receiving runoff from a coal mine waste dump in the Elk River Valley of southeast British Columbia was assessed for potential selenium uptake. Selenite [SeO32-, Se(IV)] was found to adsorb to the washed sediment at pH 7 to 8, whereas no selenate [SeO42-, Se(VI)] was adsorbed, in the concentration range of 8 to 225 μg L-1 Se as selenite or selenate. Sulfate- and selenate-reducing bacterial activity was detected in the sediment. In the presence of sulfate-reducing bacteria growth medium, Se as selenate was reduced from 619(±53) μg L-1 to 15(±0.7) μg L-1, and in the presence of selenate-reducing bacteria growth medium, Se as selenate was reduced from 364(±66) mg L-1 to 22(±10) mg L-1. Semi-continuous microcosms containing sediment overlaid with selenate (500 μg L-1 Se) and sulfate (0.9 g L-1) containing water were amended with plant debris from the site or nutrients (lactate and fertilizer). Potential selenate reduction rate (0.76 h-1) was highest in the unamended microcosms. Amendment with plant debris from the site had a negative effect on selenate reduction rate in the short term (after one hour) and a positive effect on Se removal in the long term (after one week). This study suggests that wetland sediments at the mine site may be important sinks for Se.

scholarly journals Underproduction of the Largest Subunit of RNA Polymerase II Causes Temperature Sensitivity, Slow Growth, and Inositol Auxotrophy in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 737-747 ◽  
Author(s):  
Jacques Archambault ◽  
David B Jansma ◽  
James D Friesen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Steady State ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Reporter Gene ◽  
Growth Medium ◽  
Temperature Sensitivity ◽  
Slow Growth ◽  
Yeast Saccharomyces Cerevisiae ◽  
Genes Encoding

Abstract In the yeast Saccharomyces cerevisiae, mutations in genes encoding subunits of RNA polymerase II (RNAPII) often give rise to a set of pleiotropic phenotypes that includes temperature sensitivity, slow growth and inositol auxotrophy. In this study, we show that these phenotypes can be brought about by a reduction in the intracellular concentration of RNAPII. Underproduction of RNAPII was achieved by expressing the gene (RPO21), encoding the largest subunit of the enzyme, from the LEU2 promoter or a weaker derivative of it, two promoters that can be repressed by the addition of leucine to the growth medium. We found that cells that underproduced RPO21 were unable to derepress fully the expression of a reporter gene under the control of the INO1 UAS. Our results indicate that temperature sensitivity, slow growth and inositol auxotrophy is a set of phenotypes that can be caused by lowering the steady-state amount of RNAPII; these results also lead to the prediction that some of the previously identified RNAPII mutations that confer this same set of phenotypes affect the assembly/stability of the enzyme. We propose a model to explain the hypersensitivity of INO1 transcription to mutations that affect components of the RNAPII transcriptional machinery.

scholarly journals How grow-and-switch gravitropism generates root coiling and root waving growth responses in Medicago truncatula

2015 ◽  
Vol 112 (42) ◽  
pp. 12938-12943 ◽  
Author(s):  
Tzer Han Tan ◽  
Jesse L. Silverberg ◽  
Daniela S. Floss ◽  
Maria J. Harrison ◽  
Christopher L. Henley ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Growth Medium ◽  
Plant Root ◽  
Experimental Studies ◽  
Optimal Strategies ◽  
Growth Responses ◽  
Inclined Plane ◽  
Rigid Barrier ◽  
Primary Roots ◽  
Root Waving

Experimental studies show that plant root morphologies can vary widely from straight gravity-aligned primary roots to fractal-like root architectures. However, the opaqueness of soil makes it difficult to observe how environmental factors modulate these patterns. Here, we combine a transparent hydrogel growth medium with a custom built 3D laser scanner to directly image the morphology of Medicago truncatula primary roots. In our experiments, root growth is obstructed by an inclined plane in the growth medium. As the tilt of this rigid barrier is varied, we find Medicago transitions between randomly directed root coiling, sinusoidal root waving, and normal gravity-aligned morphologies. Although these root phenotypes appear morphologically distinct, our analysis demonstrates the divisions are less well defined, and instead, can be viewed as a 2D biased random walk that seeks the path of steepest decent along the inclined plane. Features of this growth response are remarkably similar to the widely known run-and-tumble chemotactic behavior of Escherichia coli bacteria, where biased random walks are used as optimal strategies for nutrient uptake.

scholarly journals Genome of the red alga Porphyridium purpureum

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Debashish Bhattacharya ◽  
Dana C. Price ◽  
Cheong Xin Chan ◽  
Huan Qiu ◽  
Nicholas Rose ◽  
...  
Keyword(s):  
Red Alga ◽  
Porphyridium Purpureum
Sign in / Sign up

Export Citation Format

Share Document