Metabolite utilization by isolated embryonic rat hearts in vitro

Development ◽  
1972 ◽  
Vol 28 (2) ◽  
pp. 235-245
Author(s):  
Steven J. Cox ◽  
David L. Gunberg

Isolated hearts from 11-, 12- and 13-day rat embryos were incubated in a simple defined salt solution to which was added a variety of single substrates. Utilization of the added substrate was determined by comparing the contractile rates of the hearts in the presence and absence of the compound being tested. Of all the compounds tested only those involved in the Embden-Meyerhof glycolytic pathway were capable of maintaining cardiac contraction at a maximum rate in the 11-day heart. This was accomplished under both aerobic and anaerobic conditions. Although glycolysis remained important, the 12- and 13-day hearts exhibited a shift in dependence towards other metabolic pathways. This conclusion was based on the observations that anaerobic glycolysis could no longer maintain maximum heart rates and that a variety of non-glycolytic compounds could be utilized for contractile activity by the 12- and 13-day organs.

1983 ◽  
Vol 92 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Yukiko Iino ◽  
Tomonori Takasaka ◽  
Etsuro Hoshino ◽  
Yutaka Kaneko ◽  
Sachiko Tomioka ◽  
...  

Organic acids in the contents of the cholesteatoma sac from 28 cases were studied by gas chromatographic technique. Five volatile fatty acids (acetate, propionate, isobutyrate, butyrate and isovalerate) and lactate were detected in large amounts, which may lower the pH of the cholesteatoma content. These acids were considered to be derived from products of anaerobic microorganisms. Therefore, the contents from 12 cases were cultured anaerobically in a glove box. Obligate microorganisms were identified in 92% of the cases and Peptococcus, Bacteroides, and Clostridium species were frequently isolated. In vitro, such obligate anaerobes produced various organic acids from the cholesteatoma content. Facultatives such as Staphylococcus aureus and Proteus mirabilis produced acetate in the content under aerobic and anaerobic conditions, whereas no organic acid was produced by Pseudomonas aeruginosa. Organic acids in the cholesteatoma content could be fermentative products made by the microorganisms, anaerobes and facultatives, which use the content as a substrate for acid production.


Parasitology ◽  
1978 ◽  
Vol 77 (3) ◽  
pp. 255-271 ◽  
Author(s):  
P. F. V. Ward ◽  
N. S. Huskisson

SummaryA comparison was made of the major excretory products when adult Haemonchus contortus worms were incubated with D-[U-14C]glucose under aerobic and anaerobic conditions. Catabolites measured were propan-1-ol, acetate, n-propionate and CO2 and the only major difference was that nearly twice as much CO2 both in terms of quantity and radioactivity was excreted under aerobic than anaerobic conditions. The worms were also much more physically active under aerobic conditions. When worms were incubated under aerobic conditions with increasing amounts of fluoroacetate their CO2 production was progressively reduced to the anaerobic level. Their movement and their ability to clump together was also progressively reduced. After aerobic incubation with fluoroacetate and D-[U-14C]g1ucose the quantity and radioactivity of citrate within worms increased greatly. When worms were similarly incubated anaerobically no increase in citrate occurred, no radioactivity was associated with the citrate and the worms appeared physically unaffected. When worms were incubated aerobically with fluoro[1-14C]acetate they produced radioactive fluorocitrate.


2004 ◽  
Vol 186 (23) ◽  
pp. 8018-8025 ◽  
Author(s):  
Victoria R. Sutton ◽  
Erin L. Mettert ◽  
Helmut Beinert ◽  
Patricia J. Kiley

ABSTRACT The ability of FNR to sense and respond to cellular O2 levels depends on its [4Fe-4S]2+ cluster. In the presence of O2, the [4Fe-4S]2+ cluster is converted to a [2Fe-2S]2+ cluster, which inactivates FNR as a transcriptional regulator. In this study, we demonstrate that ∼2 Fe2+ ions are released from the reaction of O2 with the [4Fe-4S]2+ cluster. Fe2+ release was then used as an assay of reaction progress to investigate the rate of [4Fe-4S]2+ to [2Fe-2S]2+ cluster conversion in vitro. We also found that there was no detectable difference in the rate of O2-induced cluster conversion for FNR free in solution compared to its DNA-bound form. In addition, the rate of FNR inactivation was monitored in vivo by measuring the rate at which transcriptional regulation by FNR is lost upon the exposure of cells to O2; a comparison of the in vitro and in vivo rates of conversion suggests that O2-induced cluster conversion is sufficient to explain FNR inactivation in cells. FNR protein levels were also compared for cells grown under aerobic and anaerobic conditions.


1971 ◽  
Vol 26 (8) ◽  
pp. 780-787 ◽  
Author(s):  
H. P. Krause ◽  
H. Probst ◽  
Fr. Schneider

Interrelations between energy metabolism and cell division were studied with permanent in vitro cultured Ehrlich-ascites-tumor-cells during the second passage in vitro. The following parameters were estimated under aerobic and anaerobic conditions and in the presence of dinitrophenol:DNA- and RNA-synthesis measured by the incorporation of 14C-thymidine and 14C-uridine; rate of glycolysis measured by lactate production; permeation of 14C-2-aminoisobutyric acid; ATP level of the cells; cell division and number of dead cells.The following results were obtained: Cell division and thymidine incorporation are obligate oxygen dependent processes. It was not possible to decide, whether respiration alone can maintain cell propagation. Respiration alone and glycolysis alone cannot maintain a normal level of ATP. Only an intact respiration can maintain the penetration of 2-aminoiso-butyric acid. Glycolysis alone and respiration alone can supply the energy for the incorporation of uridine. The incorporation of uridine is also influenced by oxygen dependent reactions not related to energy production. The number of dead cells does not rise significantly under anaerobic conditions.


2002 ◽  
Vol 46 (5) ◽  
pp. 1561-1563 ◽  
Author(s):  
David H. Wright ◽  
Brent W. Gunderson ◽  
Laurie B. Hovde ◽  
Gigi H. Ross ◽  
Khalid H. Ibrahim ◽  
...  

ABSTRACT Six strains of staphylococci were exposed to levofloxacin, moxifloxacin, or trovafloxacin in an in vitro pharmacodynamic model under both aerobic and anaerobic conditions. Each agent demonstrated a rapid 3-log10 kill versus susceptible isolates regardless of condition. Against clinical isolates with reduced susceptibility, regrowth occurred by 24 h and was frequently associated with further increases in MICs.


2020 ◽  
Vol 77 (8) ◽  
pp. 1580-1589
Author(s):  
Ira M. Sigar ◽  
Amber Kaminski ◽  
Brent Ito ◽  
Jayme Christoffersen-Cebi ◽  
Aleksandra Vidovich ◽  
...  

2003 ◽  
Vol 47 (1) ◽  
pp. 398-399 ◽  
Author(s):  
Brent W. Gunderson ◽  
Khalid H. Ibrahim ◽  
Charles A. Peloquin ◽  
Laurie B. Hovde ◽  
John C. Rotschafer

ABSTRACT Methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium were exposed to linezolid (MIC of 2 mg/liter) under aerobic or anaerobic conditions in an in vitro pharmacodynamic model. Drug concentration and half-life were adjusted to simulate clinical dosing (600 mg twice daily) of linezolid. Linezolid produced a 2-log10 killing at 24 h, and rates of killing against each of these facultative organisms as measured by mean survival time appeared similar under aerobic and anaerobic conditions.


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