Irradiance and temperature regulation of oxygenic photosynthesis and O 2 consumption in a hypersaline cyanobacterial mat (Solar Lake, Egypt)

2000 ◽  
Vol 137 (1) ◽  
pp. 71-85 ◽  
Author(s):  
A. Wieland ◽  
M. Kühl
Keyword(s):  
Temperature Regulation ◽  
Oxygenic Photosynthesis ◽  
Cyanobacterial Mat ◽  
Solar Lake

scholarly journals Spirochaeta sinaica sp. nov., a halophilic spirochaete isolated from a cyanobacterial mat

2015 ◽  
Vol 65 (Pt_11) ◽  
pp. 3872-3877 ◽  
Author(s):  
Galina Dubinina ◽  
Margarita Grabovich ◽  
Nataliya Leshcheva ◽  
Sabine Gronow ◽  
Ekaterina Gavrish ◽  
...  
Keyword(s):  
Gene Sequence ◽  
Novel Species ◽  
Rrna Gene ◽  
Cyanobacterial Mat ◽  
Glucose Fermentation ◽  
Free Living ◽  
Nitrogenous Compounds ◽  
Gene Sequence Analysis ◽  
Solar Lake

A strain of free-living obligately anaerobic, halophilic spirochaete, SLT, was isolated from a sample of a cyanobacterial mat of the hypersaline Solar Lake, Sinai shore. The strain had motile helical cells, 0.35–0.40 × 6–10 μm. Strain SLT exhibited high resistance to NaCl among known halophilic spirochaetes growing at NaCl concentrations from 2 to 12 % (optimum growth at 7 %). The strain grew at temperatures from 10 to 32 °C (optimum at 28 °C) and pH from 6 to 8.5 (optimum at pH 7.0–7.5). Carbohydrates, but not alcohols, organic acids or nitrogenous compounds (peptone, yeast extract and amino acids), were used as energy substrates for growth. Ethanol, acetate, lactate, H2 and CO2 were the products of glucose fermentation. Sulfide was produced in the presence of S0 or thiosulfate in the medium. The DNA G+C content was 44.7 mol%. Based on 16S rRNA gene sequence analysis, strain SLT clustered within the genus Spirochaeta, exhibiting 94.2 and 93.7 % similarity with its closest relatives, Spirochaeta bajacaliforniensis DSM 160554T and Spirochaeta smaragdinae DSM 11293T, respectively; similarity with other species did not exceed 86 %. The phenotypic and chemotaxonomic characteristics of the strain, as well as the results of phylogenetic analysis support the classification of strain SLT as representing a novel species of the genus Spirochaeta, for which the name Spirochaeta sinaica sp. nov. is proposed. The type strain is SLT ( = DSM 14994 = UNIQEM U 783).

scholarly journals Sulfate-Reducing Bacteria and Their Activities in Cyanobacterial Mats of Solar Lake (Sinai, Egypt)

1998 ◽  
Vol 64 (8) ◽  
pp. 2943-2951 ◽  
Author(s):  
Andreas Teske ◽  
Niels B. Ramsing ◽  
Kirsten Habicht ◽  
Manabu Fukui ◽  
Jan Küver ◽  
...  
Keyword(s):  
Surface Layer ◽  
Sulfate Reduction ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Sulfate Reducing Bacteria ◽  
Cyanobacterial Mat ◽  
Sulfate Reducing ◽  
Gradient Gel Electrophoresis ◽  
Solar Lake ◽  
Sulfate Reduction Rates ◽  
Reducing Bacteria

ABSTRACT The sulfate-reducing bacteria within the surface layer of the hypersaline cyanobacterial mat of Solar Lake (Sinai, Egypt) were investigated with combined microbiological, molecular, and biogeochemical approaches. The diurnally oxic surface layer contained between 106 and 107 cultivable sulfate-reducing bacteria ml−1 and showed sulfate reduction rates between 1,000 and 2,200 nmol ml−1 day−1, both in the same range as and sometimes higher than those in anaerobic deeper mat layers. In the oxic surface layer and in the mat layers below, filamentous sulfate-reducing Desulfonema bacteria were found in variable densities of 104 to 106cells ml−1. A Desulfonema-related, diurnally migrating bacterium was detected with PCR and denaturing gradient gel electrophoresis within and below the oxic surface layer. Facultative aerobic respiration, filamentous morphology, motility, diurnal migration, and aggregate formation were the most conspicuous adaptations of Solar Lake sulfate-reducing bacteria to the mat matrix and to diurnal oxygen stress. A comparison of sulfate reduction rates within the mat and previously published photosynthesis rates showed that CO2 from sulfate reduction in the upper 5 mm accounted for 7 to 8% of the total photosynthetic CO2 demand of the mat.

Solid insulation drying of 110 kV paper-oil instrument transformers

2009 ◽  
Vol 25 (25) ◽  
pp. 35-38 ◽  
Author(s):  
Gerards Gavrilovs ◽  
Sandra Vītoliņa
Keyword(s):  
Temperature Regulation ◽  
Drying Method ◽  
Instrument Transformers ◽  
Conventional Drying ◽  
Solid Insulation

Solid insulation drying of 110 kV paper-oil instrument transformersInfluence of moisture on the instrument transformers' paper-oil insulation and its further maintenance is described in this paper. Improved insulation drying method using vacuum and temperature regulation with definite regulation algorithm of parameters is proposed and analyzed by comparing it with conventional drying method.

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