Survival value of chemotaxis in mixed cultures

1976 ◽  
Vol 22 (12) ◽  
pp. 1771-1773 ◽  
Author(s):  
Wendy K. Pilgram ◽  
Fred D. Williams
Keyword(s):  
Amino Acid ◽  
Acid Medium ◽  
Proteus Mirabilis ◽  
Mixed Cultures

A motile, chemotactic strain of Proteus mirabilis outgrew a motile, non-chemotactic mutant in a semisolid, amino acid medium, although the two strains grew equally well in broth.

Heterologous expression and characterization of l-amino acid deaminases from Proteus mirabilis in Escherichia coli

2008 ◽  
Vol 136 ◽  
pp. S300 ◽  
Author(s):  
Jin-Oh Baek ◽  
Jeong-Woo Seo ◽  
Ohsuk Kwon ◽  
Su-Il Seong ◽  
Ik-Hwan Kim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Heterologous Expression ◽  
Proteus Mirabilis

scholarly journals Active Expression of Membrane-Bound L-Amino Acid Deaminase from Proteus mirabilis in Recombinant Escherichia coli by Fusion with Maltose-Binding Protein for Enhanced Catalytic Performance

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 215
Author(s):  
Dan-Ping Zhang ◽  
Xiao-Ran Jing ◽  
An-Wen Fan ◽  
Huan Liu ◽  
Yao Nie ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Proteus Mirabilis ◽  
Binding Protein ◽  
Catalytic Efficiency ◽  
Maltose Binding Protein ◽  
Catalytic Performance ◽  
Cell Lysate ◽  
Active Expression ◽  
Membrane Bound

L-amino acid deaminases (LAADs) are membrane flavoenzymes that catalyze the deamination of neutral and aromatic L-amino acids to α-keto acids and ammonia. LAADs can be used to develop many important biotechnological applications. However, the transmembrane α-helix of LAADs restricts its soluble active expression and purification from a heterologous host, such as Escherichia coli. Herein, through fusion with the maltose-binding protein (MBP) tag, the recombinant E. coli BL21 (DE3)/pET-21b-MBP-PmLAAD was constructed and the LAAD from Proteus mirabilis (PmLAAD) was actively expressed as a soluble protein. After purification, the purified MBP-PmLAAD was obtained. Then, the catalytic activity of the MBP-PmLAAD fusion protein was determined and compared with the non-fused PmLAAD. After fusion with the MBP-tag, the catalytic efficiency of the MBP-PmLAAD cell lysate was much higher than that of the membrane-bound PmLAAD whole cells. The soluble MBP-PmLAAD cell lysate catalyzed the conversion of 100 mM L-phenylalanine (L-Phe) to phenylpyruvic acid (PPA) with a 100% yield in 6 h. Therefore, the fusion of the MBP-tag not only improved the soluble expression of the PmLAAD membrane-bound protein, but also increased its catalytic performance.

Isolation of Labeled Lipoprotein from Escherichia coli and Proteus mirabilis after Incubation with [14C]Penicillin

1985 ◽  
Vol 40 (5-6) ◽  
pp. 415-420 ◽  
Author(s):  
Gerhard Gruner ◽  
Monier H. Tadros ◽  
Roland Plapp
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Proteus Mirabilis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Apparent Molecular Weight ◽  
Penicillin G ◽  
Free Form ◽  
E Coli

Abstract [14C]penicillin binding experiments and membrane analysis were carried out with cell envelope preparations from Escherichia coli and Proteus mirabilis. After incubation with [14C] penicillin G labeled free lipoprotein could be identified. The analysis of the isolated lipoprotein by SDS polyacrylamide gel electrophoresis indicates that there is only one protein with an apparent molecular weight of 7000. The amino acid composition of isolated labeled free lipoprotein from E. coli was identical to the lipoprotein already found in E. coli. It is a point of interest that the amino acid composition of the isolated labeled free lipoprotein from P. mirabilis D52 differs from that found in other mutants of this strain. The free form of lipoprotein from P. mirabilis D52 is composed of 61 amino acids and has glycine, phenylalanine and proline as specific components.

scholarly journals Purification and characterization of three forms of glutathione transferase from Proteus mirabilis

1988 ◽  
Vol 255 (3) ◽  
pp. 971-975 ◽  
Author(s):  
C Di Ilio ◽  
A Aceto ◽  
R Piccolomini ◽  
N Allocati ◽  
A Faraone ◽  
...  
Keyword(s):  
Amino Acid ◽  
Isoelectric Focusing ◽  
Proteus Mirabilis ◽  
Gel Electrophoresis ◽  
Glutathione Transferase ◽  
Total Activity ◽  
Purification And Characterization ◽  
Substrate Specificities ◽  
Structural Differences

Three forms of glutathione transferase (GST) with pI values of 6.0, 6.4 and 7.3 were isolated from Proteus mirabilis AF 2924 by glutathione-affinity chromatography followed by isoelectric focusing, and their structural, kinetic and immunological properties were investigated. Upon SDS/polyacrylamide-slab-gel electrophoresis, all forms proved to be composed of two subunits of identical (22,500) Mr. GST-6.0 and GST-6.4 together account for about 95% of the total activity, whereas GST-7.3 is present only in trace amounts. Extensive similarities have been found between GST-6.0 and GST-6.4. These include subunit molecular mass, amino acid composition, substrate specificities and immunological characteristics. GST-7.3 also cross-reacted (non-identity) with antisera raised against bacterial GST-6.0. None of the antisera raised against a number of human, rat and mouse GSTs cross-reacted with the bacterial enzymes, indicating major structural differences between them and the mammalian GSTs. This conclusion is further supported by c.d. spectra.

A Study of Substituent Effect on the Oxidative Strengths of N-Chloroarenesulphonamides: Kinetics of Oxidation of Leucine and Isoleucine in Aqueous Acid Medium

2004 ◽  
Vol 59 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Mahesha Shetty ◽  
B. Thimme Gowda
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ionic Strength ◽  
Acid Medium ◽  
Benzene Ring ◽  
Thermodynamic Data ◽  
Substituent Effect ◽  
Kinetics Of Oxidation ◽  
Aqueous Acid ◽  
Kinetics Of

Abstract To study the variation of oxidative strengths of N-chloro-arenesulphonamides with substitution in the benzene ring, six mono- and five di-substituted N-chloro-arenesulphonamides are employed as oxidants for studying the kinetics of oxidation of two neutral amino acids, L-leucine and Lisoleucine in aqueous acid medium. The N-chloro-arenesulphonamides studied are of the constitution: ArSO2NaNCl·H2O (where Ar = C6H5, 4-CH3C6H4, 4-C2H5C6H4, 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 2,3-(CH3)2C6H3, 2,4-(CH3)2C6H3, 2-CH3-4-ClC6H3, 2,4-Cl2C6H3, and 3,4-Cl2C6H3). The reactions show second order kinetics in [oxidant], fractional order in [amino acid] and inverse dependence on [H+]. Addition of the reduced product of the oxidants or variation in ionic strength of the medium has no significant effect on the rates of oxidations. A two-pathway mechanism is considered to explain the experimental results. Effective oxidizing species of the oxidants is Cl+ in different forms. Therefore the oxidising strengths of N-chloro-arenesulphonamides depend on the ease with which Cl+ is released from them. The study reveals that the introduction of substituent in the benzene ring of the oxidant affects both the kinetic and thermodynamic data for the oxidations The electron releasing groups such as CH3 generally inhibit the rates, while electron-withdrawing groups such as Cl enhance this ability, as the electron withdrawing groups ease the release of Cl+ from the reagents and hence increase the oxidising strengths. The on Ea and logA and validity of the Hammett and isokinetic relationships for the oxidations are also analysed.

scholarly journals Diversity of TEM Mutants in Proteus mirabilis

1999 ◽  
Vol 43 (11) ◽  
pp. 2671-2677 ◽  
Author(s):  
R. Bonnet ◽  
C. De Champs ◽  
D. Sirot ◽  
C. Chanal ◽  
R. Labia ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Proteus Mirabilis ◽  
Clinical Isolates ◽  
Amino Acid Substitutions ◽  
First Report ◽  
Conjugative Plasmids ◽  
Extended Spectrum ◽  
Nucleotide Mutation

ABSTRACT In a survey of resistance to amoxicillin among clinical isolates ofProteus mirabilis, 10 TEM-type β-lactamases were characterized: (i) the well-known penicillinases TEM-1 and TEM-2, the extended-spectrum β-lactamases (ESBLs) TEM-3 and TEM-24, and the inhibitor-resistant TEM (IRT) TEM-44 and (ii) five novel enzymes, a penicillinase TEM-57 similar to TEM-1, an ESBL TEM-66 similar to TEM-3, and three IRTs, TEM-65, TEM-73, and TEM-74. The penicillinase TEM-57 and the ESBL TEM-66 differed from TEM-1 and TEM-3, respectively, by the amino acid substitution Gly-92→Asp (nucleotide mutation G-477→A). This substitution could have accounted for the decrease in pIs (5.2 for TEM-57 and 6.0 for TEM-66) but did not necessarily affect the intrinsic activities of these enzymes. The IRT TEM-65 was an IRT-1-like IRT (Cys-244) related to TEM-2 (Lys-39). The two other IRTs, TEM-73 and TEM-74, were related to IRT-1 (Cys-244) and IRT-2 (Ser-244), respectively, and harbored the amino acid substitutions Leu-21→Phe and Thr-265→Met. In this study, the ESBLs TEM-66, TEM-24, and TEM-3 were encoded by large (170- to 180-kb) conjugative plasmids that exhibited similar patterns after digestion and hybridization with the TEM and AAC(6′)I probes. The three IRTs TEM-65, TEM-73, and TEM-74 were encoded by plasmids that ranged in size from 42 to 70 kb but for which no transfer was obtained. The characterization of five new plasmid-mediated TEM-type β-lactamases and the first report of TEM-24 in P. mirabilis are evidence of the wide diversity of β-lactamases produced in this species and of its possible role as a β-lactamase-encoding plasmid reservoir.

Mixed Culture Fermentations To Improve Nutritional Value of Corn Meal1

1988 ◽  
Vol 51 (11) ◽  
pp. 866-868
Author(s):  
M. L. FIELDS ◽  
A. AL-SHOSHAN ◽  
Y. POOSIRI
Keyword(s):  
Amino Acid ◽  
Mixed Culture ◽  
Nutritional Value ◽  
Nutritive Value ◽  
Mixed Cultures ◽  
Corn Meal ◽  
One Step ◽  
Significant Change ◽  
Amino Acid Balance ◽  
Relative Nutritive Value

One-step fermentation involving two microorganisms inoculated at the same time and two-step fermentations involving two inoculations of different microbes at different times were used to enrich corn meal. Starch in corn meal was first hydrolyzed by amylases of B. stearothermophilus, E. fibuligera or A. oryzae followed by the growth of C. utilis. The combination of E. fibuligera and C. utilis produced a significant (P<0.05) increase in lysine, methionine, tryptophan. The relative nutritive value (%), which reflected the amino acid balance, increased significantly (P<0.05) with this sequence of microorganisms. Niacin, riboflavin, and thiamin increased significantly (P<0.05) when mixed cultures of A. oryzae and E. fibuligera in combination with C. utilis were employed. When E. fibuligera alone was grown, no significant change was observed in thiamin content but significant increases occurred in niacin and riboflavin. A. oryzae by itself produced significant (P<0.05) changes in niacin, riboflavin and thiamin.

scholarly journals TEM-89 β-Lactamase Produced by a Proteus mirabilis Clinical Isolate: New Complex Mutant (CMT 3) with Mutations in both TEM-59 (IRT-17) and TEM-3

2001 ◽  
Vol 45 (12) ◽  
pp. 3591-3594 ◽  
Author(s):  
Catherine Neuwirth ◽  
Stephanie Madec ◽  
Eliane Siebor ◽  
Andre Pechinot ◽  
Jean-Marie Duez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Clinical Isolate ◽  
Amino Acid Substitution ◽  
Proteus Mirabilis ◽  
Hydrolytic Activity ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Clinical Strain ◽  
Almost All

ABSTRACT TEM-89 (CMT-3) is the first complex mutant β-lactamase produced by a clinical strain of Proteus mirabilis (strain Pm 631). This new enzyme, which has a pI of 6.28, is derived from TEM-3 and has a single amino acid substitution also encountered in TEM-59 (inhibitor-resistant TEM β-lactamase IRT-17): Ser-130 to Gly. TEM-89 hydrolyzed penicillins to the same extent that TEM-3 did but lost almost all hydrolytic activity for cephalosporins and, like TEM-59, was highly resistant to inhibitors.

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