scholarly journals Solvent Stress Response of the Denitrifying Bacterium “Aromatoleum aromaticum” Strain EbN1

2008 ◽  
Vol 74 (8) ◽  
pp. 2267-2274 ◽  
Author(s):  
Kathleen Trautwein ◽  
Simon Kühner ◽  
Lars Wöhlbrand ◽  
Thomas Halder ◽  
Kenny Kuchta ◽  
...  
Keyword(s):  
Stress Responses ◽  
Aromatic Compounds ◽  
Gel Electrophoresis ◽  
Physiological Responses ◽  
Dry Weight ◽  
Anaerobic Growth ◽  
Solvent Concentration ◽  
Denitrifying Bacterium ◽  
Aromatic Substrates ◽  
Difference Gel Electrophoresis

ABSTRACT The denitrifying betaproteobacterium “Aromatoleum aromaticum” strain EbN1 degrades several aromatic compounds, including ethylbenzene, toluene, p-cresol, and phenol, under anoxic conditions. The hydrophobicity of these aromatic solvents determines their toxic properties. Here, we investigated the response of strain EbN1 to aromatic substrates at semi-inhibitory (about 50% growth inhibition) concentrations under two different conditions: first, during anaerobic growth with ethylbenzene (0.32 mM) or toluene (0.74 mM); and second, when anaerobic succinate-utilizing cultures were shocked with ethylbenzene (0.5 mM), toluene (1.2 mM), p-cresol (3.0 mM), and phenol (6.5 mM) as single stressors or as a mixture (total solvent concentration, 2.7 mM). Under all tested conditions impaired growth was paralleled by decelerated nitrate-nitrite consumption. Additionally, alkylbenzene-utilizing cultures accumulated poly(3-hydroxybutyrate) (PHB) up to 10% of the cell dry weight. These physiological responses were also reflected on the proteomic level (as determined by two-dimensional difference gel electrophoresis), e.g., up-regulation of PHB granule-associated phasins, cytochrome cd1 nitrite reductase of denitrification, and several proteins involved in oxidative (e.g., SodB) and general (e.g., ClpB) stress responses.

scholarly journals Anaerobic Degradation of p-Ethylphenol by “Aromatoleum aromaticum” Strain EbN1: Pathway, Regulation, and Involved Proteins

2008 ◽  
Vol 190 (16) ◽  
pp. 5699-5709 ◽  
Author(s):  
Lars Wöhlbrand ◽  
Heinz Wilkes ◽  
Thomas Halder ◽  
Ralf Rabus
Keyword(s):  
Stress Responses ◽  
Anaerobic Degradation ◽  
Degradation Pathway ◽  
Anaerobic Growth ◽  
Spectrometric Analysis ◽  
Aromatic Solvent ◽  
Difference Gel Electrophoresis ◽  
Pathway Regulation ◽  
Induced Proteins ◽  
Chromatographic Mass

ABSTRACT The denitrifying “Aromatoleum aromaticum” strain EbN1 was demonstrated to utilize p-ethylphenol under anoxic conditions and was suggested to employ a degradation pathway which is reminiscent of known anaerobic ethylbenzene degradation in the same bacterium: initial hydroxylation of p-ethylphenol to 1-(4-hydroxyphenyl)-ethanol followed by dehydrogenation to p-hydroxyacetophenone. Possibly, subsequent carboxylation and thiolytic cleavage yield p-hydroxybenzoyl-coenzyme A (CoA), which is channeled into the central benzoyl-CoA pathway. Substrate-specific formation of three of the four proposed intermediates was confirmed by gas chromatographic-mass spectrometric analysis and also by applying deuterated p-ethylphenol. Proteins suggested to be involved in this degradation pathway are encoded in a single large operon-like structure (∼15 kb). Among them are a p-cresol methylhydroxylase-like protein (PchCF), two predicted alcohol dehydrogenases (ChnA and EbA309), a biotin-dependent carboxylase (XccABC), and a thiolase (TioL). Proteomic analysis (two-dimensional difference gel electrophoresis) revealed their specific and coordinated upregulation in cells adapted to anaerobic growth with p-ethylphenol and p-hydroxyacetophenone (e.g., PchF up to 29-fold). Coregulated proteins of currently unknown function (e.g., EbA329) are possibly involved in p-ethylphenol- and p-hydroxyacetophenone-specific solvent stress responses and related to other aromatic solvent-induced proteins of strain EbN1.

Proteomic Analysis of Leaves of the Chlorophyll-Deficient Wheat Mutant Mt6172 and Its Wild-Type through 2D-Difference Gel Electrophoresis

2013 ◽  
Vol 38 (9) ◽  
pp. 1592-1606 ◽  
Author(s):  
Su-Jie SONG ◽  
Jia-Yu GU ◽  
Hui-Jun GUO ◽  
Lin-Shu ZHAO ◽  
Shi-Rong ZHAO ◽  
...  
Keyword(s):  
Proteomic Analysis ◽  
Gel Electrophoresis ◽  
Wild Type ◽  
Difference Gel Electrophoresis ◽  
Wheat Mutant

Social isolation of goats: significance of visual contact with conspecifics on behavioral and physiological responses

2021 ◽  
Author(s):  
Govind Kannan ◽  
Zaira M Estrada-Reyes ◽  
Phaneendra Batchu ◽  
Brou Kouakou ◽  
Thomas H Terrill ◽  
...  
Keyword(s):  
Social Isolation ◽  
Stress Responses ◽  
Repeated Measures ◽  
Physiological Stress ◽  
Physiological Responses ◽  
Average Weight ◽  
Median Frequency ◽  
Visual Contact ◽  
Time Interaction ◽  
Rank Score

Abstract Social isolation can increase distress in goats, particularly when they cannot maintain visual contact with conspecifics. This experiment was conducted to determine the behavioral and physiological responses in goats during isolation with or without visual contact with conspecifics. Male Spanish goats (uncastrated, 8-mo old, average weight 29.4 ± 0.59 kg) were randomly assigned to a control (CO) group with no isolation or to one of four isolation treatment (TRT) pens (1.5 × 1.5 m) with: (1) open grill panels but with no visual contact with conspecifics (IO), (2) covered grill to prevent visual contact (IC), (3) open grill with visual contact (IV), or (3) covered grill with a 30 × 30 cm window to allow visual contact (IW) for 90 min of social isolation (n = 12 goats/TRT). Blood samples were collected at 0, 30, 60, and 90 min (Time) from isolated and control goats. The experiment was repeated one week later using the same animals, with each goat being subjected to the same isolation treatment the second time to study the effect of prior exposure to isolation. Friedman’s Two-Way ANOVA by Ranks Test in SAS showed that the median frequency of vocalization (rank score) in goats was high in IO group, low in IV and IW groups, and intermediate in IC group (P < 0.01). Vocalization rank score was also higher (P < 0.01) during the first 30 min of isolation in goats. Median frequency of visual contact was higher in the IW group than in the IV group (P < 0.01). Frequency of climbing behavior was high in IC and IO groups, low in IV group, and intermediate in IW group (P < 0.01). Repeated Measures Analysis using GLM procedures in SAS revealed that plasma cortisol and glucose concentrations tended (P < 0.1) to be the highest in IO group than in CO, IC, IV, and IW groups. Cortisol levels were also higher (Time; P < 0.05) at 0 and 90 min compared to 30 and 60 min. Norepinephrine concentrations decreased (P < 0.05) with Time, and plasma non-esterified fatty acid (NEFA) levels were affected by TRT × Time interaction (P < 0.01). Overall, epinephrine, norepinephrine, glucose, and NEFA concentrations were lower (P < 0.01) and cortisol concentrations and lymphocyte counts higher (P < 0.01) when goats were exposed to isolation the second time. The results showed that goats with no visual contact with conspecifics during social isolation had greater physiological stress responses and spent more time vocalizing or trying to escape the pen, which may indicate distress.

Sign in / Sign up

Export Citation Format

Share Document