Faculty Opinions recommendation of Host proteasomal degradation generates amino acids essential for intracellular bacterial growth.

2011 ◽  
Author(s):  
Peter Murray
Keyword(s):  
Amino Acids ◽  
Bacterial Growth ◽  
Proteasomal Degradation

Host Proteasomal Degradation Generates Amino Acids Essential for Intracellular Bacterial Growth

Science ◽  
2011 ◽  
Vol 334 (6062) ◽  
pp. 1553-1557 ◽  
Author(s):  
C. T. D. Price ◽  
T. Al-Quadan ◽  
M. Santic ◽  
I. Rosenshine ◽  
Y. Abu Kwaik
Keyword(s):  
Amino Acids ◽  
Bacterial Growth ◽  
Proteasomal Degradation

scholarly journals Biosynthesis of Amino Acids in Xanthomonas oryzae pv. oryzae Is Essential to Its Pathogenicity

2019 ◽  
Vol 7 (12) ◽  
pp. 693 ◽  
Author(s):  
Ting Li ◽  
Zhaohong Zhan ◽  
Yunuan Lin ◽  
Maojuan Lin ◽  
Qingbiao Xie ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Bacterial Growth ◽  
Acid Synthesis ◽  
Xanthomonas Oryzae ◽  
Host Responses ◽  
Amino Acid Synthesis ◽  
Rice Bacterial Blight ◽  
Nutrient Environment ◽  
Blight Disease

Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice bacterial blight disease, which causes a large reduction in rice production. The successful interaction of pathogens and plants requires a particular nutrient environment that allows pathogen growth and the initiation of both pathogen and host responses. Amino acid synthesis is essential for bacterial growth when bacteria encounter amino acid-deficient environments, but the effects of amino acid synthesis on Xoo pathogenicity are unclear. Here, we systemically deleted the essential genes (leuB, leuC, leuD, ilvC, thrC, hisD, trpC, argH, metB, and aspC) involved in the synthesis of different amino acids and analyzed the effects of these mutations on Xoo virulence. Our results showed that leucine, isoleucine, valine, histidine, threonine, arginine, tryptophan, and cysteine syntheses are essential to Xoo infection. We further studied the role of leucine in the interaction between pathogens and hosts and found that leucine could stimulate some virulence-related responses and regulate Xoo pathogenicity. Our findings highlight that amino acids not only act as nutrients for bacterial growth but also play essential roles in the Xoo and rice interaction.

Elucidation and Therapeutic Targeting Of The Molecular Mechanism Of TRIB2-Mediated Acute Myeloid Leukaemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3792-3792
Author(s):  
Fiona Lohan ◽  
Ciaran Forde ◽  
Mara Salome ◽  
Caitriona O'Connor ◽  
Fiona Bailey ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cell Death ◽  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Kinase Activity ◽  
Proteasomal Degradation ◽  
Myeloid Differentiation ◽  
Direct Binding ◽  
Targeted Inhibition ◽  
Acute Myeloid

Abstract The pseudokinase TRIB2 is a potent acute myeloid leukaemia (AML) oncogene, capable of inducing transplantable AML with a relatively short latency in murine models. Functionally, the oncogencity of TRIB2 has been linked to its degradation of CCAAT/enhancer binding-protein-alpha (C/EBPα), a transcription factor necessary for regulation of haematopoietic stem cells (HSC) and myeloid differentiation and is mutated in ∼10-15% of cytogenetically normal AMLs. Previously, we have demonstrated that elevated TRIB2 mRNA expression is associated with a small subset of C/EBPα dysregulated AML patients. However in our analysis of primary AML patient samples we reveal detectably high TRIB2 protein expression in a greater number of samples than predicted from mRNA studies compared to normal peripheral blood mononuclear cells. Here, using in vivo ubiquitination assays we determined that TRIB2 exerts its effect through K48 specific ubiquitin-dependent proteasomal degradation of C/EBPα. Peptide array analysis identified the specific amino acids involved in the direct binding of these two proteins. Site-directed mutagenesis of these amino acids demonstrated that the direct binding of TRIB2 and C/EBPα was required for TRIB2-mediated C/EBPα degradation. In order to determine if posttranslational modification of C/EBPα was a trigger for TRIB2-mediated binding and degradation, we assessed the phosphorylation of C/EBPα, often a modification involved in target substrate ubiquitination. We found that TRIB2 decreased the levels of phosphorylated Serine 21 (S21) C/EBPα through preferential binding to the phosphorylated form of S21 C/EBPα and mediating its K48 specific ubiquitin-dependent proteasomal degradation. While TRIB2 retains the canonical amino acid motifs of a kinase and the ability to bind ATP, indicative of kinase activity, the absence of phosphorylated S21 C/EBPα in the presence of TRIB2 suggests that it does not have sufficient kinase activity to enable efficient phosphotransfer. The presence of TRIB2 further blocked the ability of mitogenic stimuli to phosphorylate S21 of C/EBPα. TRIB2 thus acts to perturb the regulation and function of C/EBPα phosphorylation ultimately leading to its degradation. We propose this contributes to the leukaemic phenotype of AML cells which include increased self-renewal and proliferation. Using clinically available inhibitors of the proteasomal degradation pathway we have investigated the targeted inhibition of the TRIB2 degradation function to induce cell death in AML cells. In TRIB2 overexpressing AML cell lines, and in AML patient samples identified to have elevated levels of TRIB2, we have demonstrated that elevated TRIB2 expressing samples are more sensitive than low TRIB2 expressing samples to cell death induced by proteasomal inhibition. Our data shows that in the presence of TRIB2 phosphorylated S21 C/EBPα is a trigger for its ubiquitin dependent degradation. We propose TRIB2 mediates is leukaemogenic effects in AML through direct protein-protein interaction, perturbation of phosphorylation signalling, resulting ultimately in proteasomal mediated degradation of its target C/EBPα. As C/EBPα plays a key role in both stem cell function and myeloid differentiation in AML, the targeted inhibition of TRIB2-mediated C/EBPα degradation may provide therapeutic avenues in AML. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Heterotrophic bacterial growth and substrate utilization in the oligotrophic Eastern Mediterranean (Aegean Sea)

2003 ◽  
Vol 4 (1) ◽  
pp. 23 ◽  
Author(s):  
U. CHRISTAKI ◽  
F.V. WAMBEKE ◽  
M. BIANCHI
Keyword(s):  
Amino Acids ◽  
Black Sea ◽  
Bacterial Growth ◽  
Bacterial Production ◽  
Sea Water ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Substrate Utilization ◽  
The Black Sea ◽  
Respiration Rates

Heterotrophic bacterial growth and substrate utilization were studied in March and September of 1997 in the oligotrophic Aegean Sea. Maximum velocities of ectoproteolytic activity (ectoaminopeptidase ctivity, EAP), as well as amino acid assimilation and respiration rates (AA-A, AA-R) were measured along with bacterial production (protein synthesis). At the northern stations which are influenced by the input of the Black Sea waters, rates at 5 m depth of EAP, AA-A and bacterial production were 2 to 3 times higher than at southern stations. Influenced by the Black Sea water, mean bacterial numbers in the 0-100 m layer showed typical oceanic concentrations averaging 0.7 x 10 6 cells ml -1 . These values, along with low bacterial production rates (30 ng C l -1 h -1 ) implied slow growth for bacteria and/or that a large number among them were inactive. Neither bacterial abundance nor production were correlated with primary production. The percentage of amino acids respired was higher in September compared to March, particularly in the northern Aegean (mean 69 %). The enzyme kinetic analysis showed a biphasic model, the transition between the high and low affinity enzymes being obtained at 50 ΜM. Ectoaminopeptidase activity was weakly correlated with bacterial production (p < 0.05), but strongly correlated with respiration rates of amino acids (p < 0.001), suggesting that the substrate used was devoted to maintain energy requirements.

scholarly journals Lysine and Threonine Biosynthesis from Aspartate Contributes to Staphylococcus aureus Growth in Calf Serum

2016 ◽  
Vol 82 (20) ◽  
pp. 6150-6157 ◽  
Author(s):  
Yuichi Oogai ◽  
Masaya Yamaguchi ◽  
Miki Kawada-Matsuo ◽  
Tomoko Sumitomo ◽  
Shigetada Kawabata ◽  
...  
Keyword(s):  
Amino Acids ◽  
Staphylococcus Aureus ◽  
Bacterial Growth ◽  
De Novo ◽  
Calf Serum ◽  
Mouse Serum ◽  
Lower Growth ◽  
Content Type ◽  
Semialdehyde Dehydrogenase ◽  
Threonine Biosynthesis

ABSTRACTStaphylococcus aureusis a human pathogen, andS. aureusbacteremia can cause serious problems in humans. To identify the genes required for bacterial growth in calf serum (CS), a library ofS. aureusmutants with randomly inserted transposons were analyzed for growth in CS, and the aspartate semialdehyde dehydrogenase (asd)-inactivated mutant exhibited significantly reduced growth in CS compared with the wild type (WT). The mutant also exhibited significantly reduced growth in medium, mimicking the concentrations of amino acids and glucose in CS. Asd is an essential enzyme for the biosynthesis of lysine, methionine, and threonine from aspartate. We constructed inactivated mutants of the genes for lysine (lysA), methionine (metE), and threonine (thrC) biosynthesis and found that the inactivated mutants oflysAandthrCexhibited significantly lower growth in CS than the WT, but the growth of themetEmutant was similar to that of the WT. The reduced growth of theasdmutant was recovered by addition of 100 μg/ml lysine and threonine in CS. These results suggest thatS. aureusrequires lysine and threonine biosynthesis to grow in CS. On the other hand, theasd-,lysA-,metE-, andthrC-inactivated mutants exhibited significantly reduced growth in mouse serum compared with the WT. In mouse bacteremia experiments, theasd-,lysA-,metE-, andthrC-inactivated mutants exhibited attenuated virulence compared with WT infection. In conclusion, our results suggest that the biosynthesis ofde novoaspartate family amino acids, especially lysine and threonine, is important for staphylococcal bloodstream infection.IMPORTANCEStudying the growth of bacteria in blood is important for understanding its pathogenicity in the host.Staphylococcus aureussometimes causes bacteremia or sepsis. However, the factors responsible forS. aureusgrowth in the blood are not well understood. In this study, using a library of 2,914 transposon-insertional mutants in theS. aureusMW2 strain, we identified the factors responsible for bacterial growth in CS. We found that inactivation of the lysine and threonine biosynthesis genes led to deficient growth in CS. However, the inactivation of these genes did not affectS. aureusgrowth in general medium. Because the concentration of amino acids in CS is low compared to that in general bacterial medium, our results suggest that lysine and threonine biosynthesis is important for the growth ofS. aureusin CS. Our findings provide new insights forS. aureusadaptation in the host and for understanding the pathogenesis of bacteremia.

scholarly journals Preliminary Note on Inhibition of Bacterial Growth by Amino-acids

1923 ◽  
Vol 21 (4) ◽  
pp. 376-385 ◽  
Author(s):  
G. A. Wyon ◽  
J. W. McLeod
Keyword(s):  
Amino Acids ◽  
Bacterial Growth ◽  
Inhibitory Concentration ◽  
Protein Digestion ◽  
High Concentration ◽  
Preliminary Note ◽  
Low Concentrations ◽  
Physical Effects ◽  
Cyclic Compounds ◽  
Suggested Explanation

While amino-acids in appropriate concentrations have long been known as valuable aids to bacterial growth, it does not appear to have been recognised that in relatively low concentrations they are often inhibitory.Inhibition has been shown to occur with 10 out of 11 single amino-acids tested and with certain mixtures rich in amino-acids. The inhibitory concetration varies from 11 to 130 millimols per litre, or from 0·2 to 2%(wt./vol. ). It is of some intrest that the amino-acids inhibitory in the lowest concentration were the cyclic compounds—histidine, tyrosine, tryphane, phenylalamine. Of the chain compounds tested cystine was the most inhibitory.Several organisus belonging to various groups of bacteria are susceptible of inhibition by amino-acids; certain intestinal organisms are not susceptible. The effect cannot be attributed to the physical effects of high concentration.There is an apparent divergence between our results and those of workers who have recommended tryptic digests for stimulating the growth of some of the bacteria here shown to be readily inhibited by amino-acids. A suggested explanation of this divergence is that it is the products of partial protein digestion, the polypetides, which are mainly responsible for the effect of stimulating growth, not the amino-acids. A “polypeptide medium” might prove particularly valuable for bacterial growth.A metabolism experiment with glycine in high but sub-inhibitory concentration showed that the amino-acid is broken down by Staphylococcus aureus, at this concentration.

scholarly journals A Novel Deaminase Involved in Chloronitrobenzene and Nitrobenzene Degradation with Comamonas sp. Strain CNB-1

2007 ◽  
Vol 189 (7) ◽  
pp. 2677-2682 ◽  
Author(s):  
Lei Liu ◽  
Jian-Feng Wu ◽  
Ying-Fei Ma ◽  
Sheng-Yue Wang ◽  
Guo-Ping Zhao ◽  
...  
Keyword(s):  
Amino Acids ◽  
Bacterial Growth ◽  
Bradyrhizobium Japonicum ◽  
Catalytic Mechanism ◽  
Rhodopseudomonas Palustris ◽  
Hydroxyl Group ◽  
Hypothetical Proteins ◽  
Terminal Sequence ◽  
Significant Similarity ◽  
Carbon And Nitrogen

ABSTRACT Comamonas sp. strain CNB-1 degrades nitrobenzene and chloronitrobenzene via the intermediates 2-aminomuconate and 2-amino-5-chloromuconate, respectively. Deamination of these two compounds results in the release of ammonia, which is used as a source of nitrogen for bacterial growth. In this study, a novel deaminase was purified from Comamonas strain CNB-1, and the gene (cnbZ) encoding this enzyme was cloned. The N-terminal sequence and peptide fingerprints of this deaminase were determined, and BLAST searches revealed no match with significant similarity to any functionally characterized proteins. The purified deaminase is a monomer (30 kDa), and its V max values for 2-aminomuconate and 2-amino-5-chloromuconate were 147 μmol·min−1·mg−1 and 196 μmol·min−1·mg−1, respectively. Its catalytic products from 2-aminomuconate and 2-amino-5-chloromuconate were 2-hydroxymuconate and 2-hydroxy-5-chloromuconate, respectively, which are different from those previously reported for the deaminases of Pseudomonas species. In the catalytic mechanism proposed, the α-carbon and nitrogen atoms (of both 2-aminomuconate and 2-amino-5-chloromuconate) were simultaneously attacked by a hydroxyl group and a proton, respectively. Homologs of cnbZ were identified in the genomes of Bradyrhizobium japonicum, Rhodopseudomonas palustris, and Roseiflexus sp. strain RS-1; these genes were previously annotated as encoding hypothetical proteins of unknown function. It is concluded that CnbZ represents a novel enzyme that deaminates xenobiotic compounds and/or α-amino acids.

scholarly journals Identification of Specific Determinants of Human APOBEC3F, APOBEC3C, and APOBEC3DE and African Green Monkey APOBEC3F That Interact with HIV-1 Vif

2010 ◽  
Vol 84 (24) ◽  
pp. 12599-12608 ◽  
Author(s):  
Jessica L. Smith ◽  
Vinay K. Pathak
Keyword(s):  
Amino Acids ◽  
Mutational Analysis ◽  
Proteasomal Degradation ◽  
African Green Monkey ◽  
Host Proteins ◽  
Immunodeficiency Virus ◽  
Green Monkey ◽  
Anti Hiv Agents ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT Human APOBEC3F (hA3F) and human APOBEC3G (hA3G) are potent anti-human immunodeficiency virus (anti-HIV) host factors that suppress viral replication by hypermutating the viral genome, inhibiting reverse transcription, and hindering integration. To overcome hA3F and hA3G, HIV-1 encodes Vif, which binds and targets these host proteins for proteasomal degradation. Previously, we reported that the hA3F-Vif interactions that lead to hA3F degradation are located in the region comprising amino acids 283 to 300. We have now performed mutational analysis of this region and found that the 289EFLARH294 amino acids contribute to hA3F-Vif binding and are critical for A3F's sensitivity to Vif. Mutants in which E289 is mutated significantly increase hA3F's ability to inhibit viral infectivity in the presence of Vif, and coimmunoprecipitation assays show that binding of Vif to the E289K mutant is decreased. We examined the role of the EFLARH sequence in other A3 proteins, including human A3C (hA3C), human A3DE (hA3DE), African green monkey A3F (agmA3F), and rhesus macaque A3F (rhA3F). hA3C, hA3DE, and agmA3F were all susceptible to degradation induced by HIV-1 Vif, while rhA3F was not. Mutagenesis of the glutamate in the EFLARH sites of hA3C, hA3DE, and agmA3F decreases the susceptibilities of these proteins to Vif-induced degradation. Together, these results indicate that the EFLARH region in hA3F, hA3C, hA3DE, and agmA3F interacts with HIV-1 Vif and that this interaction plays a role in the Vif-mediated proteasomal degradation of these A3 proteins. These studies identify a conserved region in 3 of 7 human A3 proteins that is critical for degradation mediated by HIV-1 Vif and provide structural insights into the hA3F-Vif interactions that could facilitate the development of a novel class of anti-HIV agents.

Determination of Free D-Amino Acids with a Bacterial Transaminase: Their Depletion Leads to Inhibition of Bacterial Growth

1994 ◽  
Vol 218 (1) ◽  
pp. 204-209 ◽  
Author(s):  
W.M. Jones ◽  
D. Ringe ◽  
K. Soda ◽  
J.M. Manning
Keyword(s):  
Amino Acids ◽  
Bacterial Growth
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