scholarly journals Sequencing and Transcriptional Analysis of the Streptococcus thermophilus Histamine Biosynthesis Gene Cluster: Factors That Affect Differential hdcA Expression

2010 ◽  
Vol 76 (18) ◽  
pp. 6231-6238 ◽  
Author(s):  
Marina Calles-Enríquez ◽  
Benjamin Hjort Eriksen ◽  
Pia Skov Andersen ◽  
Fergal P. Rattray ◽  
Annette H. Johansen ◽  
...  
Keyword(s):  
Streptococcus Thermophilus ◽  
Stationary Growth Phase ◽  
Cell Number ◽  
Fermented Food ◽  
Transcriptional Analysis ◽  
Growth Phases ◽  
Stationary Growth ◽  
Biosynthesis Gene Cluster ◽  
Polycistronic Mrna ◽  
Maximum Expression

ABSTRACT Histamine, a toxic compound that is formed by the decarboxylation of histidine through the action of microbial decarboxylases, can accumulate in fermented food products. From a total of 69 Streptococcus thermophilus strains screened, two strains, CHCC1524 and CHCC6483, showed the capacity to produce histamine. The hdc clusters of S. thermophilus CHCC1524 and CHCC6483 were sequenced, and the factors that affect histamine biosynthesis and histidine-decarboxylating gene (hdcA) expression were studied. The hdc cluster began with the hdcA gene, was followed by a transporter (hdcP), and ended with the hdcB gene, which is of unknown function. The three genes were orientated in the same direction. The genetic organization of the hdc cluster showed a unique organization among the lactic acid bacterial group and resembled those of Staphylococcus and Clostridium species, thus indicating possible acquisition through a horizontal transfer mechanism. Transcriptional analysis of the hdc cluster revealed the existence of a polycistronic mRNA covering the three genes. The histidine-decarboxylating gene (hdcA) of S. thermophilus demonstrated maximum expression during the stationary growth phase, with high expression levels correlated with high histamine levels. Limited expression was evident during the lag and exponential growth phases. Low-temperature (4°C) incubation of milk inoculated with a histamine-producing strain showed lower levels of histamine than did inoculated milk kept at 42°C. This reduction was attributed to a reduction in the activity of the HdcA enzyme itself rather than a reduction in gene expression or the presence of a lower cell number.

Mise en évidence d'une activité uréasique chez Streptococcus thermophilus

1988 ◽  
Vol 34 (6) ◽  
pp. 818-822 ◽  
Author(s):  
V. Juillard ◽  
M. J. Desmazeaud ◽  
H. E. Spinnler
Keyword(s):  
Amino Acids ◽  
Urease Activity ◽  
Culture Medium ◽  
Colorimetric Method ◽  
Streptococcus Thermophilus ◽  
Stationary Growth Phase ◽  
Optimal Temperature ◽  
Ammonium Ions ◽  
Stationary Growth ◽  
Optimal Ph

In Streptococcus thermophilus CNRZ 404, the presence of urease activity was demonstrated by means of a specific colorimetric method for ammonium ions. The main physicochemical properties of the enzyme were determined. The Km with urea as substrate was 1.19 mM and the optimal pH was approximately 7.5. Because both thermolability and enzyme activity increased as the temperature was increased to 70 °C, the optimal temperature could not be determined with precision. Urease activity was maximal at the beginning of the stationary growth phase; it was stimulated by the presence of urea and of certain amino acids such as arginine and glutamic acid in the culture medium. This activity has been detected in several other strains of Streptococcus thermophilus. [Translated by the journal]

scholarly journals Proteome-Wide Analysis of Trypanosoma cruzi Exponential and Stationary Growth Phases Reveals a Subcellular Compartment-Specific Regulation

Genes ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 413 ◽  
Author(s):  
Carla Avila ◽  
Simon Mule ◽  
Livia Rosa-Fernandes ◽  
Rosa Viner ◽  
María Barisón ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Stationary Phase ◽  
Growth Phase ◽  
Ribosomal Proteins ◽  
Stationary Growth Phase ◽  
Exponential Phase ◽  
Insect Vector ◽  
Growth Phases ◽  
Stationary Growth ◽  
Subcellular Compartment

Trypanosoma cruzi, the etiologic agent of Chagas disease, cycles through different life stages characterized by defined molecular traits associated with the proliferative or differentiation state. In particular, T. cruzi epimastigotes are the replicative forms that colonize the intestine of the Triatomine insect vector before entering the stationary phase that is crucial for differentiation into metacyclic trypomastigotes, which are the infective forms of mammalian hosts. The transition from proliferative exponential phase to quiescent stationary phase represents an important step that recapitulates the early molecular events of metacyclogenesis, opening new possibilities for understanding this process. In this study, we report a quantitative shotgun proteomic analysis of the T. cruzi epimastigote in the exponential and stationary growth phases. More than 3000 proteins were detected and quantified, highlighting the regulation of proteins involved in different subcellular compartments. Ribosomal proteins were upregulated in the exponential phase, supporting the higher replication rate of this growth phase. Autophagy-related proteins were upregulated in the stationary growth phase, indicating the onset of the metacyclogenesis process. Moreover, this study reports the regulation of N-terminally acetylated proteins during growth phase transitioning, adding a new layer of regulation to this process. Taken together, this study reports a proteome-wide rewiring during T. cruzi transit from the replicative exponential phase to the stationary growth phase, which is the preparatory phase for differentiation.

The Lipid Composition of the Coccolithophore Emiliania Huxleyi and Its Possible Ecophysiological Significance

1996 ◽  
Vol 76 (3) ◽  
pp. 579-594 ◽  
Author(s):  
D.W. Pond ◽  
R.P. Harris
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Stationary Phase ◽  
Stationary Phases ◽  
Stationary Growth Phase ◽  
Emiliania Huxleyi ◽  
Growth Phases ◽  
Stationary Growth ◽  
South African Isolate ◽  
Total Fatty Acids

The lipid class and fatty acid composition of eight geographically disperse isolates of Emiliania huxleyi, grown under 12 h L:D cycles and harvested during logarithmic and stationary growth phases, were examined. Cell size and chlorophyll content tended to decrease from logarithmic to stationary growth phase, Methyl and ethyl ketones were the dominant lipid classes, although proportions exhibited no clear pattern either between strains or growth phases. Neutral lipid hardly accumulated over the course of the growth experiments, and triacylglycerol was either absent or only present at low levels. In all strains with the exception of a South African isolate, levels of total fatty acid per cell decreased markedly between logarithmic and stationary phases, primarily attributable to reductions in the levels of saturated and monounsaturated fatty acids. Major fatty acids in all strains during both growth phases were 14:0,16:0,18:1 (n-9), 18:4 (n-3), 18:5 (n-3) and 22:6 (n-3). Although all strains were rich in polyunsaturated fatty acids (47–72% of total fatty acids) stationary phase cultures consistently contained the highest proportions. The polyunsaturated fatty acid docosahexanoic acid (22:6, n-3) was the most abundant fatty acid in all strains, comprising a maximum of 38·4% of total fatty acids in strain M 181 during stationary phase. Multivariate analysis (PCA) allowed logarithmic and stationary phase cultures to be distinguished although no obvious intra-isolate variability was apparent. The results are discussed in terms of the importance of lipids for the ecophysiology of E. huxleyi and the role of this dominant coccolithophore in the marine food chain.

Differences in the Lipid Distribution in Subcellular Fractions of Mouse Fibroblasts Derived from Logarithmic and Stationary Growth

1976 ◽  
Vol 31 (3-4) ◽  
pp. 179-185 ◽  
Author(s):  
Hans Peter Kulas ◽  
F. Alfred Anderer
Keyword(s):  
Plasma Membrane ◽  
Lipid Class ◽  
Growth Phase ◽  
Membrane Fraction ◽  
Stationary Growth Phase ◽  
Subcellular Fractions ◽  
Cell Populations ◽  
Growth Phases ◽  
Stationary Growth ◽  
Mouse Fibroblasts

Abstract The lipid class compositions of subcellular fractions of SV40-transformed mouse fibroblasts derived from the logarithmic and stationary growth phase were compared. Cell populations of the stationary growth phase showed a relative decrease of the protein content and an increase of triglycerides and alkoxydiglycerides which could be located in the non-sedimenting fraction and in the nuclei and mitochondria containing fraction, respectively. Furtheron, distinct shifts in the subcellular distribution of those lipid classes could be observed which exhibited no relative overall increase or decrease when the cells of both growth phases were compared. In the crude plasma membrane fraction the ratio “lipid class/protein” remained about constant with the exception of the phospholipids and alkoxydiglycerides.

scholarly journals Conversion of Daidzein and Genistein by an Anaerobic Bacterium Newly Isolated from the Mouse Intestine

2008 ◽  
Vol 74 (15) ◽  
pp. 4847-4852 ◽  
Author(s):  
Anastasia Matthies ◽  
Thomas Clavel ◽  
Michael Gütschow ◽  
Wolfram Engst ◽  
Dirk Haller ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Enzyme Induction ◽  
Growth Phase ◽  
Anaerobic Bacterium ◽  
Stationary Growth Phase ◽  
Gut Bacteria ◽  
Soy Isoflavones ◽  
Strictly Anaerobic ◽  
Stationary Growth ◽  
Mouse Intestine

ABSTRACT The metabolism of isoflavones by gut bacteria plays a key role in the availability and bioactivation of these compounds in the intestine. Daidzein and genistein are the most common dietary soy isoflavones. While daidzein conversion yielding equol has been known for some time, the corresponding formation of 5-hydroxy-equol from genistein has not been reported previously. We isolated a strictly anaerobic bacterium (Mt1B8) from the mouse intestine which converted daidzein via dihydrodaidzein to equol as well as genistein via dihydrogenistein to 5-hydroxy-equol. Strain Mt1B8 was a gram-positive, rod-shaped bacterium identified as a member of the Coriobacteriaceae. Strain Mt1B8 also transformed dihydrodaidzein and dihydrogenistein to equol and 5-hydroxy-equol, respectively. The conversion of daidzein, genistein, dihydrodaidzein, and dihydrogenistein in the stationary growth phase depended on preincubation with the corresponding isoflavonoid, indicating enzyme induction. Moreover, dihydrogenistein was transformed even more rapidly in the stationary phase when strain Mt1B8 was grown on either genistein or daidzein. Growing the cells on daidzein also enabled conversion of genistein. This suggests that the same enzymes are involved in the conversion of the two isoflavones.

scholarly journals The extracellular proteome of Rhizobium etli CE3 in exponential and stationary growth phase

2010 ◽  
Vol 8 (1) ◽  
pp. 51 ◽  
Author(s):  
Niurka Meneses ◽  
Guillermo Mendoza-Hernández ◽  
Sergio Encarnación
Keyword(s):  
Growth Phase ◽  
Stationary Growth Phase ◽  
Rhizobium Etli ◽  
Stationary Growth ◽  
Extracellular Proteome

scholarly journals Antibacterial Activity of Some Lactic Acid Bacteria Isolated from an Algerian Dairy Product

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Abdelkader Mezaini ◽  
Nour-Eddine Chihib ◽  
Abdelkader Dilmi Bouras ◽  
Naima Nedjar-Arroume ◽  
Jean Pierre Hornez
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antibacterial Effect ◽  
Dairy Product ◽  
Streptococcus Thermophilus ◽  
Fermented Food ◽  
Bacteriocin Production ◽  
Gram Positive ◽  
Bacteria Growth ◽  
Gram Positive Bacteria

In the present study, the antibacterial effect of 20 lactic acid bacteria isolates from a traditional cheese was investigated. 6 isolates showed antibacterial effect against Gram positive bacteria.Streptococcus thermophilusT2 strain showed the wide inhibitory spectrum against the Gram positive bacteria. Growth and bacteriocin production profiles showed that the maximal bacteriocin production, byS. thermophilusT2 cells, was measured by the end of the late-log phase (90 AUml−1) with a bacteriocine production rate of 9.3 (AUml−1)h−1. In addition, our findings showed that the bacteriocin, produced byS. thermophilusT2, was stable over a wide pH range (4–8); this indicates that such bacteriocin may be useful in acidic as well as nonacidic food. This preliminarily work shows the potential application of autochthonous lactic acid bacteria to improve safety of traditional fermented food.

scholarly journals Impact of two disinfectants on detachment of Enterococcus faecalis from polythene in aquatic microcosm

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
C. Lontsi Djimeli ◽  
A. Tamsa Arfao ◽  
V Rossi ◽  
N Nsulem ◽  
V Raspal ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Adhesion ◽  
Enterococcus Faecalis ◽  
Sodium Hypochlorite ◽  
Growth Phases ◽  
Planktonic Cells ◽  
Stationary Growth ◽  
Experimental Conditions ◽  
The Impact ◽  
Aquatic Microcosm

<p><strong>After cell adhesion processes in microcosm, the impact of sodium hypochlorite (NaOCl) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) on the detachment of <em>Enterococcus faecalis </em>from polythene fragments immersed in water under stationary and dynamic conditions was assessed. The abundance of planktonic cells was also evaluated. The density of <em>E. faecalis</em> adhered in absence of disinfectant fluctuated between 2 and 4 units (Log CFU/cm<sup>2</sup>). </strong><strong>After living in disinfected water, </strong><strong>the density of <em>E. faecalis</em> remained adhered to polythene sometimes reached 2 units (Log CFU/Cm<sup>2</sup>)</strong><strong>. </strong><strong>This highest abundance of cells remained adhered was recorded with cells coming from the lag, exponential and stationary growth phases in water treated with 0.5‰ NaOCl. In H<sub>2</sub>O<sub>2</sub> disinfected water, the highest value was recorded at all cells growth phases with 5‰ H<sub>2</sub>O<sub>2 </sub>concentration. Adhered <em>E. faecalis</em> cells have been sometimes completely or partially decimated respectively by NaOCl and H<sub>2</sub>O<sub>2</sub> treated water. Considering separately each experimental condition, it was noted that increasing the concentration of disinfectant caused a significant decrease (P≤0.01) in abundance of cells stay adhered after living in water disinfected by the two disinfectants. Changes in disinfectant concentrations in different experimental conditions had an impact on the detachment of <em>E. faecalis</em> cells from the substrates. </strong></p>

BIOPOLYMERIC ASSOCIATIONS IN BACTERIAL SUBCELLULAR FRACTIONS

1967 ◽  
Vol 13 (12) ◽  
pp. 1641-1654 ◽  
Author(s):  
E. E. Woodside ◽  
C. A. Frick ◽  
C. W. Fishel
Keyword(s):  
Escherichia Coli ◽  
Trichloroacetic Acid ◽  
Hydrolytic Enzymes ◽  
Coli Strain ◽  
Alkaline Degradation ◽  
Growth Phases ◽  
Stationary Growth ◽  
Dna And Rna ◽  
Phenol Water ◽  
Logarithmic Growth

Greater amounts of intracellularly bound glucans were present in Escherichia coli, strain B/r cells, in the late lag and logarithmic growth phases than in cells in the early lag and stationary growth phases. Bound alkali-stable and alkali-labile glucose-containing polymers— as well as unbound glucans—were further characterized by their susceptibility to hydrolysis by alpha-amylase and by their trichloroacetic acid (TCA) – ethanol solubility characteristics. A combination of phenol/water fractionation and TCA–ethanol partitioning of acetone-dried cells revealed the presence of bound glucose-containing polymers in the crude lipopolysaccharide, protein, DNA, and RNA subcellular fractions.Purified lipopolysaccharides from Escherichia coli, strains B, B/r, and Bs, contained both alkali-stable and alkali-labile glucose polymers. Similarly, alkaline hydrolysis and TCA–ethanol partitioning of both phenol- and TCA-extracted endotoxin preparations yielded numerous carbohydrate-containing subfractions. The carbohydrate monomers associated with lipopolysaccharide fractions of Escherichia species were more susceptible to alkaline degradation than the monomeric constituents present in Salmonella and Shigella lipopolysaccharide preparations. Upon exposure to either hydrolytic enzymes or gelatin, the phenol-extracted lipopolysaccharides were further partitioned into numerous lipopolysaccharide- and (or) homopolysaccharide–biopolymeric complexes by TCA-ethanol fractionation.

Sign in / Sign up

Export Citation Format

Share Document