scholarly journals Cytoplasmic and Periplasmic Proteomic Signatures of Exponentially Growing Cells of the Psychrophilic BacteriumPseudoalteromonas haloplanktisTAC125

2010 ◽  
Vol 77 (4) ◽  
pp. 1276-1283 ◽  
Author(s):  
Boris Wilmes ◽  
Holger Kock ◽  
Susanne Glagla ◽  
Dirk Albrecht ◽  
Birgit Voigt ◽  
...  

ABSTRACTThe psychrophilic model bacteriumPseudoalteromonas haloplanktisis characterized by remarkably fast growth rates under low-temperature conditions in a range from 5°C to 20°C. In this study the proteome of cellular compartments, the cytoplasm and periplasm, ofP. haloplanktisstrain TAC125 was analyzed under exponential growth conditions at a permissive temperature of 16°C. By means of two-dimensional protein gel electrophoresis and mass spectrometry, a first inventory of the most abundant cytoplasmic and periplasmic proteins expressed in a peptone-supplemented minimal medium was established. By this approach major enzymes of the amino acid catabolism of this marine bacterium could be functionally deduced. The cytoplasmic proteome showed a predominance of amino acid degradation pathways and tricarboxylic acid (TCA) cycle enzymes but also the protein synthesis machinery. Furthermore, high levels of cold acclimation and oxidative stress proteins could be detected at this moderate growth temperature. The periplasmic proteome was characterized by a significant abundance of transporters, especially of highly expressed putative TonB-dependent receptors. This high capacity for protein synthesis, efficient amino acid utilization, and substrate transport may contribute to the fast growth rates of the copiotrophic bacteriumP. haloplanktisin its natural environments.

1984 ◽  
Vol 4 (6) ◽  
pp. 1063-1072 ◽  
Author(s):  
G P Thomas ◽  
M B Mathews

Amino acid analogs, like other effectors of the stress response, induce in mammalian cells the same gene products that are induced upon heat shock; incorporation of the analog into protein is required for induction. We show here that induction by analogs involves controls operating at the levels of both transcription and translation. The electrophoretic patterns of newly made mRNAs simplify with time such that the putative stress protein mRNAs are the only species transported from the nucleus. Concomitantly, the patterns of protein synthesis simplify such that the stress proteins become nearly exclusive polypeptide products. Although the normal mRNAs are either not used or used with greatly reduced efficiency, they are not degraded and retain translatability when transferred to cell-free systems. Soon after the stress response has been induced, there follows a defect in the initiation of polypeptide chains, as evidenced by examination of polysome profiles. Upon prolonged exposure, polysomes are recovered, and although they give rise to stress proteins almost exclusively, the normal mRNAs are still present in these structures. Thus, in addition to the initiation defect, a lesion in elongation may also be involved. The extreme sensitivity of protein synthesis to the inhibition of RNA synthesis, together with the parallel simplifications in the patterns of newly made mRNAs and polypeptides, may imply that only newly made mRNAs are efficiently translated in analog-treated cells.


1984 ◽  
Vol 4 (6) ◽  
pp. 1063-1072
Author(s):  
G P Thomas ◽  
M B Mathews

Amino acid analogs, like other effectors of the stress response, induce in mammalian cells the same gene products that are induced upon heat shock; incorporation of the analog into protein is required for induction. We show here that induction by analogs involves controls operating at the levels of both transcription and translation. The electrophoretic patterns of newly made mRNAs simplify with time such that the putative stress protein mRNAs are the only species transported from the nucleus. Concomitantly, the patterns of protein synthesis simplify such that the stress proteins become nearly exclusive polypeptide products. Although the normal mRNAs are either not used or used with greatly reduced efficiency, they are not degraded and retain translatability when transferred to cell-free systems. Soon after the stress response has been induced, there follows a defect in the initiation of polypeptide chains, as evidenced by examination of polysome profiles. Upon prolonged exposure, polysomes are recovered, and although they give rise to stress proteins almost exclusively, the normal mRNAs are still present in these structures. Thus, in addition to the initiation defect, a lesion in elongation may also be involved. The extreme sensitivity of protein synthesis to the inhibition of RNA synthesis, together with the parallel simplifications in the patterns of newly made mRNAs and polypeptides, may imply that only newly made mRNAs are efficiently translated in analog-treated cells.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Dunfang Wang ◽  
Xuran Ma ◽  
Shanshan Guo ◽  
Yanli Wang ◽  
Tao Li ◽  
...  

As a classic prescription, Huangqin Tang (HQT) has been widely applied to treat ulcerative colitis (UC), although its pharmacological mechanisms are not clear. In this study, urine metabolomics was first analysed to explore the therapeutic mechanisms of HQT in UC rats induced by TNBS. We identified 28 potential biomarkers affected by HQT that might cause changes in urine metabolism in UC rats, mapped the network of metabolic pathways, and revealed how HQT affects metabolism of UC rats. The results showed that UC affects amino acid metabolism and biosynthesis of unsaturated fatty acids and impairs the tricarboxylic acid cycle (TCA cycle). UC induced inflammatory and gastrointestinal reactions by inhibiting the transport of fatty acids and disrupting amino acid metabolism. HQT plays key roles via regulating the level of biomarkers in the metabolism of amino acids, lipids, and so on, normalizing metabolic disorders. In addition, histopathology and other bioinformatics analysis further confirm that HQT altered UC rat physiology and pathology, ultimately affecting metabolic function of UC rats.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1435
Author(s):  
Hee Seo ◽  
Jae-Han Bae ◽  
Gayun Kim ◽  
Seul-Ah Kim ◽  
Byung Hee Ryu ◽  
...  

The use of probiotic starters can improve the sensory and health-promoting properties of fermented foods. This study aimed to evaluate the suitability of probiotic lactic acid bacteria (LAB) as a starter for kimchi fermentation. Seventeen probiotic type strains were tested for their growth rates, volatile aroma compounds, metabolites, and sensory characteristics of kimchi, and their characteristics were compared to those of Leuconostoc (Le.) mesenteroides DRC 1506, a commercial kimchi starter. Among the tested strains, Limosilactobacillus fermentum, Limosilactobacillus reuteri, Lacticaseibacillus rhamnosus, Lacticaseibacillus paracasei, and Ligilactobacillus salivarius exhibited high or moderate growth rates in simulated kimchi juice (SKJ) at 37 °C and 15 °C. When these five strains were inoculated in kimchi and metabolite profiles were analyzed during fermentation using GC/MS and 1H-NMR, data from the principal component analysis (PCA) showed that L. fermentum and L. reuteri were highly correlated with Le. mesenteroides in concentrations of sugar, mannitol, lactate, acetate, and total volatile compounds. Sensory test results also indicated that these three strains showed similar sensory preferences. In conclusion, L. fermentum and L. reuteri can be considered potential candidates as probiotic starters or cocultures to develop health-promoting kimchi products.


Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 117
Author(s):  
Thekla Cordes ◽  
Christian M. Metallo

Itaconate is a small molecule metabolite that is endogenously produced by cis-aconitate decarboxylase-1 (ACOD1) in mammalian cells and influences numerous cellular processes. The metabolic consequences of itaconate in cells are diverse and contribute to its regulatory function. Here, we have applied isotope tracing and mass spectrometry approaches to explore how itaconate impacts various metabolic pathways in cultured cells. Itaconate is a competitive and reversible inhibitor of Complex II/succinate dehydrogenase (SDH) that alters tricarboxylic acid (TCA) cycle metabolism leading to succinate accumulation. Upon activation with coenzyme A (CoA), itaconyl-CoA inhibits adenosylcobalamin-mediated methylmalonyl-CoA (MUT) activity and, thus, indirectly impacts branched-chain amino acid (BCAA) metabolism and fatty acid diversity. Itaconate, therefore, alters the balance of CoA species in mitochondria through its impacts on TCA, amino acid, vitamin B12, and CoA metabolism. Our results highlight the diverse metabolic pathways regulated by itaconate and provide a roadmap to link these metabolites to potential downstream biological functions.


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