scholarly journals Aerobic and anaerobic reduction of birnessite by a novel Dietzia strain

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Huiqin Zhang ◽  
Yan Li ◽  
Xin Wang ◽  
Anhuai Lu ◽  
Hongrui Ding ◽  
...  
2001 ◽  
Vol 67 (3) ◽  
pp. 1076-1084 ◽  
Author(s):  
Jeff McLean ◽  
Terry J. Beveridge

ABSTRACT A pseudomonad (CRB5) isolated from a decommissioned wood preservation site reduced toxic chromate [Cr(VI)] to an insoluble Cr(III) precipitate under aerobic and anaerobic conditions. CRB5 tolerated up to 520 mg of Cr(VI) liter−1 and reduced chromate in the presence of copper and arsenate. Under anaerobic conditions it also reduced Co(III) and U(VI), partially internalizing each metal. Metal precipitates were also found on the surface of the outer membrane and (sometimes) on a capsule. The results showed that chromate reduction by CRB5 was mediated by a soluble enzyme that was largely contained in the cytoplasm but also found outside of the cells. The crude reductase activity in the soluble fraction showed aKm of 23 mg liter−1 (437 μM) and a V max of 0.98 mg of Cr h−1 mg of protein−1 (317 nmol min−1 mg of protein−1). Minor membrane-associated Cr(VI) reduction under anaerobiosis may account for anaerobic reduction of chromate under nongrowth conditions with an organic electron donor present. Chromate reduction under both aerobic and anaerobic conditions may be a detoxification strategy for the bacterium which could be exploited to bioremediate chromate-contaminated or other toxic heavy metal-contaminated environments.


1986 ◽  
Vol 59 ◽  
pp. 309-324 ◽  
Author(s):  
Zora Djurić ◽  
David W. Potter ◽  
Robert H. Heflich ◽  
Frederick A. Beland

1972 ◽  
Vol 27 (02) ◽  
pp. 263-271 ◽  
Author(s):  
I. A. Cooper ◽  
P Cochrane ◽  
B. G. Firkin ◽  
K. J. Pinkard

SummaryIt has been suggested that human platelets possess the ability to phagocytose particulate matter similar to the polymorphonuclear leukocyte. However some difference of opinion has arisen regarding this contention, particularly as differences have been demonstrated with regard to the observed metabolic changes occurring in platelets related to such a process.The experiments reported in this paper were designed to observe the aerobic and anaerobic metabolism in human platelets during and following interiorization of two different particles, viz. polystyrene latex and thorotrast. The results of these experiments show a marked difference between both types of particles with regard to observable metabolic changes despite the rapid interiorization of both types of material. Some alteration occurs in both aerobic and anaerobic metabolism a considerable time after interiorization of latex, whereas no alteration could be demonstrated after interiorization of thorotrast. It is suggested that the interiorization of particulate matter is by some process other than phagocytosis and that observed metabolic changes related to latex may be due to a release reaction.


2020 ◽  
Vol 33 (2) ◽  
pp. 102-105
Author(s):  
Joanna Bialowska ◽  
Witold Bojar ◽  
Tomasz Zareba ◽  
Stefan Tyski ◽  
Barbara Tymczyna-Borowicz

AbstractCross-infection involves the transmission of microorganisms through secretions, bodily fluids and excreta, as well as undisinfected surfaces and medical equipment. In the dental office, diseases are transmitted via various routes, e.g. from patient to dentist or other member of dental team, from doctor or dental team member to patient, from patient to another patient, from dental office to community and from community to patient. The study was conducted to evaluate the effectiveness of infection control in dental practices based on the qualitative and quantitative assessment of microbiological contaminants detected on the surface of filling material packaging used in dental offices. The material for research were 9 packages containing dental materials during their use in 3 dental settings. The packages were placed in sterile flasks and rinsed to wash microorganisms from the surfaces. The washes were filtered through membrane filters and cultured under proper aerobic and anaerobic conditions, and at elevated CO2 concentration. Microbial growth on TIO and TSB media was observed. The contamination of most samples remained low as indicated by the growth from one to a maximum of five colonies on TSA. The contamination remained at the level of 10-50 CFU/package, i.e. <100 CFU/single package. The tests evaluating the contamination of dental package surfaces with aerobic bacteria confirmed high hygiene standards observed in dental offices from which the packages were brought.


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