Biochemical changes accompanying the long-term starvation of Micrococcus luteus cells in spent growth medium

1995 ◽  
Vol 163 (5) ◽  
pp. 373-379 ◽  
Author(s):  
G. V. Mukamolova ◽  
N. D. Yanopolskaya ◽  
T. V. Votyakova ◽  
V. I. Popov ◽  
A. S. Kaprelyants ◽  
...  
Keyword(s):  
Growth Medium ◽  
Micrococcus Luteus ◽  
Biochemical Changes

scholarly journals Regulated proliferation of primitive hematopoietic progenitor cells in long-term human marrow cultures

Blood ◽  
1985 ◽  
Vol 66 (4) ◽  
pp. 1002-1005 ◽  
Author(s):  
J Cashman ◽  
AC Eaves ◽  
CJ Eaves
Keyword(s):  
Growth Medium ◽  
Specific Activity ◽  
High Specific Activity ◽  
Cell Types ◽  
Hematopoietic Progenitor Cell ◽  
Specific Cell ◽  
Quiescent State ◽  
Hematopoietic Progenitor ◽  
Marrow Cultures

We have examined the cycling status of various classes of erythroid and granulopoietic progenitor populations maintained for many weeks in standard normal long-term human marrow cultures. These were initiated with a single inoculum of marrow aspirate and were routinely fed by weekly removal of half of the nonadherent cells and replacement of half of the growth medium. Progenitors of large erythroid colonies (more than eight erythroblast clusters) present in the nonadherent fraction and progenitors of small granulocyte/macrophage colonies (fewer than 500 cells) present in both the nonadherent and adherent fractions were found to be actively cycling at all times examined (28% to 63% kill following a 20-minute exposure to 20 microCi/mL of high specific activity 3H-thymidine). In contrast, progenitors of large granulocyte/macrophage colonies (more than 500 cells) and progenitors of large erythroid colonies (more than eight erythroblast clusters), present in the adherent layer, consistently alternated between a quiescent state at the time of each weekly medium change and a proliferating state two to three days later (0% to 13% kill and 21% to 49% kill, respectively). Additional experiments revealed that the activation of primitive progenitors in the adherent layer was not dependent on the addition of fresh glutamine or hydrocortisone, nor on the physical manipulations involved in changing the growth medium. These studies provide the first direct evidence that normal long-term human marrow cultures support the continued turnover of a variety of early hematopoietic progenitor cell types. Further, they indicate that the proliferative activity of the most primitive of these progenitors is regulated by stage-specific cell-cell interactions that are subject to manipulation.

Functional differentiation of nitrate-reducing isolates regulated by long-term fertilization in a rice paddy soil

2020 ◽  
pp. 1-9
Author(s):  
Xing Chen ◽  
Yi Liu ◽  
Chunmei Liu ◽  
Wenzhao Zhang ◽  
Hongling Qin ◽  
...  
Keyword(s):  
Growth Medium ◽  
Normal Growth ◽  
Rice Paddy ◽  
Functional Differentiation ◽  
Fertilizer Treatment ◽  
Potassium Fertilizer ◽  
Nutritional Conditions ◽  
Nitrate Reducers ◽  
Nitrite Production

Fertilization can cause obvious shifts in nitrate-reducing community composition in agricultural ecosystems; however, little is known about the behaviors and functional characters of isolated nitrate reducers adapted to a specific environment. In this study, 849 nitrate-reducing bacteria were isolated from various fertilization treatments in a long-term paddy field experiment; the isolates were further characterized in functions with both culture-dependent and independent methodologies. The results showed that CK (no fertilizer) treatment had four genera with even relative abundance, whereas the other three treatments had their own predominant genera with Chromobacterium in nitrogen (N) fertilizer, Serratia in NPK (nitrogen, phosphorus, and potassium fertilizer) and Enterobacter in NPKC treatment (NPK plus rice straw). The isolates of Serratia and Enterobacter grew faster and produced significantly more nitrites than those of Chromobacterium and Burkholderia in the normal growth medium, suggesting that the dominant isolates from nutrient-rich environment, such as NPK and NPKC treatments, are better adapted to high nutritional conditions. On the contrary, the strains of Chromobacterium and Burkholderia possessed stronger nitrite production ability in comparison with the isolates of Serratia and Enterobacter in the diluted growth medium, indicating that the selected isolates from CK and N treatments have the capability to develop under nutrient-limiting conditions. Our results indicated that the behaviors and functions of nitrate reducers appears to be important in adapting to their dwelling habitats.

Biochemical changes in needles of Pinus radiata D. Don trees in relationship to long-term ozone exposure indices

2001 ◽  
Vol 114 (3) ◽  
pp. 325-335 ◽  
Author(s):  
I. Calzada ◽  
J. Mesanza ◽  
H. Casado ◽  
F.J. Castillo
Keyword(s):  
Pinus Radiata ◽  
Biochemical Changes ◽  
Ozone Exposure
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