scholarly journals Acetylene reduction (dinitrogen fixation) by clinical isolates of Klebsiella pneumoniae

1977 ◽  
Vol 6 (5) ◽  
pp. 456-460
Author(s):  
C A Chambers ◽  
W S Silver
Keyword(s):  
Klebsiella Pneumoniae ◽  
Optimum Condition ◽  
Yeast Extract ◽  
Acetylene Reduction ◽  
Incubation Temperature ◽  
Dinitrogen Fixation ◽  
Clinical Strains ◽  
Cultural Conditions ◽  
High Incidence ◽  
Reduction Assay

Freshly isolated clinical strains of Klebsiella were tested for the ability to fix dinitrogen by the acetylene reduction assay. Ability to detect this trait was markedly affected by cultural conditions. When the test was run at 37 degrees C in the presence of yeast extract (50 mg/liter), only 1.6% of the organisms were diazotrophs, whereas this temperature without yeast extract yielded 12.9% positive cultures. The optimum condition found was 28 degrees C without yeast extract (21.9% positive); therefore, search for diazotrophy in clinical strains should not be conducted at the usual incubation temperature. There was a high incidence of indole-positive strains among diazotrophs. No such correlation was noted with any other biochemical trait or antibiotic susceptibility tested. The significance of this correlation is not apparent.

Bacterial dinitrogen fixation in the leaf of the northern pitcher plant (Sarracenia purpurea)

1991 ◽  
Vol 69 (10) ◽  
pp. 2296-2298 ◽  
Author(s):  
Andrew B. Prankevicius ◽  
Duncan M. Cameron
Keyword(s):  
Key Words ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Dinitrogen Fixation ◽  
Acetylene Reduction Assay ◽  
Sarracenia Purpurea ◽  
Pitcher Plant ◽  
Physiological Conditions ◽  
Reduction Assay ◽  
Unidentified Source

Bacterial (Azotobacteriaceae) nitrogenase activity in the leaf cavity of the insectivorous northern pitcher plant (Sarracenia purpurea L.) was assessed by acetylene reduction assay. Results indicated that bacterial dinitrogen fixation occurs in the leaf cavity under normal physiological conditions. This may represent a previously unidentified source of nitrogen for the pitcher plant, as the level of nitrogenase activity measured was sufficient to provide the plant with nitrogen well in excess of that required. Key words: pitcher plant, Sarracenia purpurea, dinitrogen fixation, Azotobacteriaceae, nitrogenase.

Corticosteroid Catabolism by Klebsiella pneumoniae as a Possible Mechanism for Increased Pneumonia Risk

2019 ◽  
Vol 20 (4) ◽  
pp. 309-316 ◽  
Author(s):  
Pritam Chattopadhyay ◽  
Goutam Banerjee
Keyword(s):  
Amino Acid ◽  
Klebsiella Pneumoniae ◽  
Kegg Pathway ◽  
Degradation Pathway ◽  
Amino Acid Sequences ◽  
Biological Mechanism ◽  
Clinical Strains ◽  
Catabolism Pathway ◽  
Steroid Catabolism ◽  
Nutrition Source

Background: Several strains of Klebsiella pneumoniae are responsible for causing pneumonia in lung and thereby causing death in immune-suppressed patients. In recent year, few investigations have reported the enhancement of K. pneumoniae population in patients using corticosteroid containing inhaler. Objectives: The biological mechanism(s) behind this increased incidence has not been elucidated. Therefore, the objective of this investigating was to explore the relation between Klebsiella pneumoniae and increment in carbapenamase producing Enterobacteriaceae score (ICS). Methods: The available genomes of K. pneumoniae and the amino acid sequences of steroid catabolism pathway enzymes were taken from NCBI database and KEGG pathway tagged with UniPort database, respectively. We have used different BLAST algorithms (tBLASTn, BLASTp, psiBLAST, and delBLAST) to identify enzymes (by their amino acid sequence) involved in steroid catabolism. Results: A total of 13 enzymes (taken from different bacterial candidates) responsible for corticosteroid degradation have been identified in the genome of K. pneumoniae. Finally, 8 enzymes (K. pneumoniae specific) were detected in four clinical strains of K. pneumoniae. This investigation intimates that this ability to catabolize corticosteroids could potentially be one mechanism behind the increased pneumonia incidence. Conclusion: The presence of corticosteroid catabolism enzymes in K. pneumoniae enhances the ability to utilize corticosteroid for their own nutrition source. This is the first report to demonstrate the corticosteroid degradation pathway in clinical strains of K. pneumoniae.

Emergence and Recovery of Ceftazidime-avibactam Resistance in blaKPC-33-Harboring Klebsiella pneumoniae Sequence Type 11 Isolates in China

2020 ◽  
Vol 71 (Supplement_4) ◽  
pp. S436-S439
Author(s):  
Qingyu Shi ◽  
Dandan Yin ◽  
Renru Han ◽  
Yan Guo ◽  
Yonggui Zheng ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Infection Control ◽  
Polymyxin B ◽  
Sequence Type ◽  
First Report ◽  
Clinical Strains

Abstract This is the first report of ceftazidime–avibactam resistance caused by the blaKPC-33 mutation through the D179Y variant during the treatment of blaKPC-2-positive Klebsiella pneumoniae-related infections in China. The blaKPC-33-containing K. pneumoniae was susceptible to meropenem–vaborbactam, cefepime–zidebactam, tigecycline, and polymyxin B. The blaKPC-33 gene was located on a 77 551-bp transformable plasmid harboring qnrS1 and blaLAP-2. Detecting blaKPC-33-positive K. pneumoniae clinical strains is important for infection control.

OBSERVATIONS ON AMYLOLYTIC BACTERIA: III. CULTURAL CONDITIONS INFLUENCING THE BREAKDOWN OF STARCH BY STENOTHERMOPHILIC BACTERIA BELONGING TO BACILLUS STEAROTHERMOPHILUS

1952 ◽  
Vol 30 (4) ◽  
pp. 360-370 ◽  
Author(s):  
Egon Stark ◽  
P. A. Tetrault
Keyword(s):  
Yeast Extract ◽  
Bacillus Stearothermophilus ◽  
Soluble Starch ◽  
The Other ◽  
Ph Changes ◽  
Proteose Peptone ◽  
Cultural Conditions ◽  
Initial Ph ◽  
Commercial Medium ◽  
Agar Media

Thirty-five cultures of Bacillus stearothermophilus hydrolyzed five starches under various cultural conditions. Hydrolysis occurred regardless of the type, brand, or batch of starch; regardless of the initial pH or of the subsequent pH changes of the medium. Starch in broth was better attacked than in agar media. Some cultures hydrolyzed 0.5%, but not 1% starch; others hydrolyzed easily 10% soluble starch. Length of incubation was important. Certain cultures never formed acid or sugar from starch. Dextrinization was a more reliable indication of starch hydrolysis than was the formation of acid or sugar. Soluble starch gave more consistent results in repeated experiments than did nonsoluble starches. The type of protein medium determines strongly the formation of amylase. Trypticase was the best commercial medium, yeast extract came second. The other 10 media yielded fewer amylolytic cultures. Yeast extract added to media enhanced amylase formation, except with trypticase. Tryptose, proteose-peptone, and neopeptone inhibited the growth of most cultures.

scholarly journals Occurrence of diazotrophic bacteria in Araucaria angustifolia

2007 ◽  
Vol 64 (3) ◽  
pp. 303-304 ◽  
Author(s):  
Rafaela de Fátima Neroni ◽  
Elke Jurandy Bran Nogueira Cardoso
Keyword(s):  
16S Rrna ◽  
Acetylene Reduction ◽  
Araucaria Angustifolia ◽  
Diazotrophic Bacteria ◽  
Araucaria Forest ◽  
Solid Media ◽  
Reduction Assay ◽  
Semi Solid ◽  
Rrna Sequences ◽  
16S Rrna Sequences

Araucaria angustifolia is an environmentally threatened tree and the whole biota of the Araucaria Forest should be investigated with the aim of its preservation. Diazotrophic bacteria are extremely important for the maintenance of ecosystems, but they have never been studied in Araucaria Forests. In this study, diazotrophic bacteria were isolated from Araucaria roots and soil, when grown in semi-specific, semi-solid media. The diazotrophic character of some recovered isolates could be confirmed using the acetylene reduction assay. According to their 16S rRNA sequences, most of these isolates belong to the genus Burkholderia.

Nitrogen fixation associated with 'Park' Kentucky bluegrass (Poapratensis L.)

1979 ◽  
Vol 25 (10) ◽  
pp. 1197-1200 ◽  
Author(s):  
R. C. Shearman ◽  
W. L. Pedersen ◽  
R. V. Klucas ◽  
E. J. Kinbacher
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Acetylene Reduction Activity ◽  
Controlled Environment ◽  
Nitrogen Accumulation ◽  
Reduction Activity ◽  
Significant Difference ◽  
Reduction Assay

Associative nitrogen fixation in Kentucky bluegrass (Poa pratensis L.) turfs inoculated with five nitrogen-fixing bacterial isolates was evaluated using the acetylene reduction assay and nitrogen accumulation as indicators of fixation. 'Park' and 'Nugget' Kentucky bluegrass turfs were grown in controlled environment chambers and inoculated with Klebsiella pneumoniae (W-2, W-6, and W-14), Erwinia herbicola (W-8), and Enterobacter cloacae (W-11). 'Park' inoculated with K. pneumoniae (W-6) had significant acetylene reduction activity using undisturbed turfs. Other treatments including turfs treated with heat-killed cells had no significant difference in acetylene reduction. In a second study, 'Park' and 'South Dakota Certified' turfs were grown in a greenhouse and inoculated with K. pneumoniae (W-6) and E. herbicola (W-8). 'Park' inoculated with K. pneumoniae (W-6) had increased acetylene reduction activity rates and also a greater nitrogen accumulation in aerial tissues when compared to controls. Acetylene reduction activity was correlated (r = 0.92) to nitrogen accumulation. Other treatments did not effectively increase acetylene reduction activity or nitrogen accumulation.

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