Pyruvate kinase from the earthworm Allolobophora calliginosa: modification of the enzyme during anaerobiosis

1991 ◽  
Vol 69 (1) ◽  
pp. 251-254
Author(s):  
Athanasios I. Papadopoulos ◽  
Basile Michaelidis ◽  
Isidoros Beis
Keyword(s):  
Pyruvate Kinase ◽  
Deae Cellulose ◽  
Relative Activity ◽  
The Body ◽  
E Coli ◽  
In Vitro Incubation ◽  
Sigmoidal Kinetics ◽  
Independent Protein

The relative activity of pyruvate kinase from the body-wall muscle of the earthworm Allolobophora calliginosa was found to drop dramatically within 6 h of exposure to N2, whereas the opposite was observed during recovery. Two forms of pyruvate kinase (designated as peak I and peak II) were separated chromatographically on DEAE-cellulose and eluted at 50 and 150 mM of KCl, respectively. They displayed different kinetic behaviour with respect to substrate phosphoenolpyruvate; peak I exhibited Michaelis–Menten kinetics whereas peak II showed sigmoidal kinetics. The ratio of the enzyme units (peak I/peak II) decreased from 3.38 under normoxic conditions to 0.09 under anoxic conditions. In vitro incubation of the aerobic form of pyruvate kinase in the presence of ATP and Mg++ resulted in a reduction of the enzyme activity by 64%, suggesting the presence of an endogenous cyclic-nucleotide-independent protein kinase capable of phosphorylating pyruvate kinase. After in vitro incubation, alkaline phosphatase from E. coli increased the depressed activity of anaerobic pyruvate kinase, indicating that the enzyme molecule is phosphorylated in vivo during exposure to anoxia.

scholarly journals Lysyl-tRNA synthetase from Escherichia coli K12. Chromatographic heterogeneity and the lysU-gene product

1987 ◽  
Vol 248 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Charlier ◽  
R Sanchez
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Activity Ratio ◽  
Deae Cellulose ◽  
Trna Synthetase ◽  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases

In contrast with most aminoacyl-tRNA synthetases, the lysyl-tRNA synthetase of Escherichia coli is coded for by two genes, the normal lysS gene and the inducible lysU gene. During its purification from E. coli K12, lysyl-tRNA synthetase was monitored by its aminoacylation and adenosine(5′)tetraphospho(5′)adenosine (Ap4A) synthesis activities. Ap4A synthesis was measured by a new assay using DEAE-cellulose filters. The heterogeneity of lysyl-tRNA synthetase (LysRS) was revealed on hydroxyapatite; we focused on the first peak, LysRS1, because of its higher Ap4A/lysyl-tRNA activity ratio at that stage. Additional differences between LysRS1 and LysRS2 (major peak on hydroxyapatite) were collected. LysRS1 was eluted from phosphocellulose in the presence of the substrates, whereas LysRS2 was not. Phosphocellulose chromatography was used to show the increase of LysRS1 in cells submitted to heat shock. Also, the Mg2+ optimum in the Ap4A-synthesis reaction is much higher for LysRS1. LysRS1 showed a higher thermostability, which was specifically enhanced by Zn2+. These results in vivo and in vitro strongly suggest that LysRS1 is the heat-inducible lysU-gene product.

scholarly journals A novel Bursin-like peptide as a potential virus inhibitor and immunity regulator in SPF chickens infected with recombinant ALV

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Yukun Zeng ◽  
Zuxin Gong ◽  
Binbin Wu ◽  
Wenchao Guan ◽  
Shenyi Yu ◽  
...  
Keyword(s):  
Growth Performance ◽  
Virus Titer ◽  
The Body ◽  
Bursa Of Fabricius ◽  
Virus Eradication ◽  
First Report ◽  
E Coli ◽  
Valuable Adjunct

Abstract Background Avian leukosis viruses (ALVs) are important contagious suppressive factors of chicken immunity and growth performance, resulted in enormous economic loss. Although virus eradication programs are applied in breeder flocks, ALVs are still widespread globally. Therefore, other valuable adjunct to reduce the negative effect of ALVs should be considered. Bursin-like peptide (BLP) showed remarkable immunomodulatory effects, whereas their influence on ALV-infected avian groups has not been reported. Here, a designed hybrid BLP was expressed in E. coli. The purified BLP was injected subcutaneously weekly in SPF chickens congenitally infected with a natural ALV strain. Then the influences of this BLP on the growth performance, immune response and virus titer of ALV-infected chickens were determined. Results This BLP injection significantly improved the body weights of ALV-infected birds (P < 0.05). BLP injection significantly enhanced organ index in the BF in ALV-infected birds (P < 0.05). The weekly injection of BLP significantly lengthened the maintenance time of antibodies against Newcastle disease virus (NDV) attenuated vaccine of ALV-infected birds (P < 0.05) and boosted the antibody titer against avian influenza virus (AIV) H5 inactive vaccine of mock chicken (P < 0.05). BLP injection in mock chickens enhanced the levels of serum cytokines (IL-2, IL-4 and interferon-γ) (P < 0.05). Surprisingly, the novel BLP significantly inhibited expression of the ALV gp85 gene in the thymus (P < 0.05), kidney (P < 0.05) and bursa of Fabricius (BF) (P < 0.01) of ALV-infected chickens. Both viral RNA copy number and protein level decreased significantly with BLP (50 μg/mL) inoculation before ALV infection in DF1 cells (P < 0.05). Conclusions This is the first report investigating the influence of BLP on the growth and immunity performance of chickens infected by ALV. It also is the first report about the antiviral effect of BLP in vivo and in vitro. This BLP expressed in E. coli showed potential as a vaccine adjuvant, growth regulator and antiretroviral drug in chickens to decrease the negative effects of ALV infection.

Cloning, functional expression, and complementation analysis of an inorganic pyrophosphatase fromBartonella bacilliformis

1997 ◽  
Vol 43 (8) ◽  
pp. 734-743 ◽  
Author(s):  
Samuel J. Mitchell ◽  
Michael F. Minnick
Keyword(s):  
Amino Acid ◽  
Functional Expression ◽  
Relative Activity ◽  
Inorganic Pyrophosphatase ◽  
Amino Acid Residues ◽  
Bartonella Bacilliformis ◽  
E Coli ◽  
Catalytic Active Site

We have cloned the inorganic pyrophosphatase gene (ppa) from the facultative intracellular pathogen Bartonella bacilliformis and characterized its encoded product. The 531-bp gene is located approximately 1 kb downstream of, and in opposite orientation to, the invasion-associated locus (ialAB) of B. bacilliformis. The predicted protein encoded by ppa is 177 amino acid residues, which is in agreement with in vitro and in vivo synthesis of a protein with an apparent molecular mass of 22–23 kDa. The predicted B. bacilliformis pyrophosphatase (PPase) sequence is 53% identical and 85% similar to the E. coli PPase (EC 3.6.1.1), and contains all 12 of the amino acid residues implicated in the catalytic active site. The isolated B. bacilliformis PPase exhibits an activity of 51 ± 2 μmol PO4released/(mg protein∙min) at 28 °C and pH 8, and is sensitive to inhibition by Ca2+. In keeping with other prokaryotic PPases, B. bacilliformis PPase activity occurs from pH 6 to 10 (optimal pH = 8) and demonstrates high thermostability in the presence of Mg2+(highest activity at 55 °C, relative activity = 80 ± 3% at pH 8). The cloned B. bacilliformis ppa is able to genetically complement a ppa−mutant strain of E. coli.Key words: Bartonella, invasion-associated locus, inorganic pyrophosphatase.

A New Class of Dimeric α-Interferons (IFN-α) Made by the Dock and Lock (DNL) Method for Improved Cancer Therapy.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1396-1396
Author(s):  
Edmund A. Rossi ◽  
William J. McBride ◽  
Diane L. Nordstrom ◽  
Preeti Trisal ◽  
Thomas M. Cardillo ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Renal Clearance ◽  
The Body ◽  
Myelogenous Leukemia ◽  
Saline Control ◽  
E Coli ◽  
New Class ◽  
Disease Therapy

Abstract Background: IFN-α2 is indicated for the therapy of hairy cell leukemia, chronic myelogenous leukemia, follicular lymphoma, and malignant melanoma. As is the case for most cytokines, the pharmacokinetic (PK) properties of IFN-α2 are critical for dosing and efficacy. In vivo, the protein is quickly degraded, diffuses widely throughout the body, and has a rapid rate of renal clearance. Pegylation of IFN-α2 significantly increases the serum half-life and reduces renal clearance, thus enhancing its efficacy. However, established pegylation of IFN-α2 results in a mixture of positional isomers and reduced in vitro activity, as known for PEGASYS (Roche) and PEG-INTRON (Schering-Plough). Methods: To improve the PK properties and the potency, the DNL method (Rossi et al. Proc. Natl. Acad. Sci. USA, 2006,103:6841) was used to generate novel agents having two copies of IFN-α2b conjugated to polyethylene glycol (PEG). Results: A fusion protein (DDD2-IFN-α2b) composed of IFN-α2b with a dimerization-and-docking domain (DDD2) and a six-His tag was expressed both in myeloma cells and in E. coli. Two PEG-based modules, each composed of a fluorescent molecule, an anchor domain (AD) and either a 20-kDa PEG (IMP362) or a 30-kDa PEG (IMP413), were synthesized. Combining DDD2-IFN-α2b and IMP362 or IMP413 under redox conditions resulted in the desirable DNL conjugates consisting of two copies of IFN-α2b and one PEG linked site-specifically via the DDD and AD interaction. The cytotoxic activity of DDD2-IFN-α2b on Daudi lymphoma cells was similar to that of commercially available recombinant IFN-α2 (rhIFN-α2). The purity and identity of the two DNL conjugates (α2b-413 and α2b-362) were demonstrated by SDS-PAGE, immunoblotting, and fluorescence imaging. Both also showed potent cytotoxic activity on Daudi cells in vitro and superior PK properties to PEG-INTRON. For example, the mean blood residence times for α2b-362 (10.3 h) and α2b-413 (21.7 h) were significantly longer than those of rhIFN-α2 (0.7 h) and PEG-INTRON (5.1 h). Initial studies in mice bearing Daudi xenografts showed a significant therapeutic advantage over PEG-INTRON for both α2b-362 and α2b-413. Animals given 14,000 IU of PEG-INTRON had a median survival (MS) of 32 days compared to 21 days for saline control, whereas those receiving α2b-362 at 14,000 IU, 7,000 IU and 3,500 IU resulted in MS of 45, 41 and 32 days, respectively. More remarkably, α2b-413 was the most effective, achieving MS of 46, >53, and >53 days with 3,500 IU, 7,000 IU and 14,000 IU, respectively, all statistically significant improvements (P< 0.0028) compared to PEG-INTRON given at each equivalent activity. Conclusions: The DNL method provides a novel pegylation strategy for generating a dimeric IFN-α2b that is linked site-specifically to a single PEG at the predetermined location. Since the resulting conjugates exhibit improved PK and efficacy in a Burkitt lymphoma model, they may represent a new class of interferons for use in cancer and infectious disease therapy.

Pyruvate kinase from Aspergillus niger: a regulatory enzyme in glycolysis?

1984 ◽  
Vol 30 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Bibiana Meixner-Monori ◽  
Christian P. Kubicek ◽  
Max Röhr
Keyword(s):  
Citric Acid ◽  
Aspergillus Niger ◽  
Pyruvate Kinase ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Acid Accumulation ◽  
Sigmoidal Kinetics ◽  
Atp Inhibition ◽  
Very High

Pyruvate kinase from the filamentous, citric acid producing fungus Aspergillus niger was purified about 100-fold by ammonium sulfate precipitation, DEAE-cellulose chromatography, and gel filtration. The addition of fructose-1,6-diphosphate was necessary to prevent loss of activity during purification. The enzyme purified in the presence of fructose-1,6-diphosphate (FDP) exhibits hyperbolic kinetics with respect to phosphoenolpyruvate (PEP) and ADP. Monovalent cations activated the enzyme (K+, NH4+). FDP neither activated nor inhibited the enzymatic activity from extracts freshly prepared in the absence of exogenous FDP; ATP showed a weak activation. In contrast the enzyme from crude extracts which had been stored in the presence of glycerol for 3 days showed activation by FDP or a metabolite thereof and inhibition by ATP. In the absence of FDP sigmoidal kinetics were obtained with respect to PEP, which became hyperbolic kinetics after addition of FDP. ATP inhibition turned into slight ATP activation in the presence of FDP. However, it was possible to reactivate inactivated pyruvate kinase (after dialysis in the absence of FDP) by adding FDP to the enzyme assay. From these results and because of the very high affinity of pyruvate kinase for FDP (Ka < 0.1 μM), it is concluded that the enzyme probably has FDP bound to the protein in vivo. The significance of this hypothesis to the regulation of glycolysis in A. niger, with special reference to the mechanism of citric acid accumulation, is discussed.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Репрограммированые in vitro на М3 фенотип макрофаги останавливают рост солидной карциномы in vivo

2018 ◽  
pp. 41-46
Author(s):  
А.А. Раецкая ◽  
С.В. Калиш ◽  
С.В. Лямина ◽  
Е.В. Малышева ◽  
О.П. Буданова ◽  
...  
Keyword(s):  
Solid Tumor ◽  
Antitumor Effect ◽  
Tumor Development ◽  
Significant Inhibition ◽  
The Body ◽  
Ehrlich Carcinoma ◽  
Solid Carcinoma ◽  
Ec Cells

Цель исследования. Доказательство гипотезы, что репрограммированные in vitro на М3 фенотип макрофаги при введении в организм будут существенно ограничивать развитие солидной карциномы in vivo . Методика. Рост солидной опухоли инициировали у мышей in vivo путем подкожной инъекции клеток карциномы Эрлиха (КЭ). Инъекцию макрофагов с нативным М0 фенотипом и с репрограммированным M3 фенотипом проводили в область формирования солидной КЭ. Репрограммирование проводили с помощью низких доз сыворотки, блокаторов факторов транскрипции STAT3/6 и SMAD3 и липополисахарида. Использовали две схемы введения макрофагов: раннее и позднее. При раннем введении макрофаги вводили на 1-е, 5-е, 10-е и 15-е сут. после инъекции клеток КЭ путем обкалывания макрофагами с четырех сторон область развития опухоли. При позднем введении, макрофаги вводили на 10-е, 15-е, 20-е и 25-е сут. Через 15 и 30 сут. после введения клеток КЭ солидную опухоль иссекали и измеряли ее объем. Эффект введения макрофагов оценивали качественно по визуальной и пальпаторной характеристикам солидной опухоли и количественно по изменению ее объема по сравнению с группой без введения макрофагов (контроль). Результаты. Установлено, что M3 макрофаги при раннем введении от начала развития опухоли оказывают выраженный антиопухолевый эффект in vivo , который был существенно более выражен, чем при позднем введении макрофагов. Заключение. Установлено, что введение репрограммированных макрофагов M3 ограничивает развитие солидной карциномы в экспериментах in vivo . Противоопухолевый эффект более выражен при раннем введении М3 макрофагов. Обнаруженные в работе факты делают перспективным разработку клинической версии биотехнологии ограничения роста опухоли, путем предварительного программирования антиопухолевого врожденного иммунного ответа «в пробирке». Aim. To verify a hypothesis that macrophages reprogrammed in vitro to the M3 phenotype and injected into the body substantially restrict the development of solid carcinoma in vivo . Methods. Growth of a solid tumor was initiated in mice in vivo with a subcutaneous injection of Ehrlich carcinoma (EC) cells. Macrophages with a native M0 phenotype or reprogrammed towards the M3 phenotype were injected into the region of developing solid EC. Reprogramming was performed using low doses of serum, STAT3/6 and SMAD3 transcription factor blockers, and lipopolysaccharide. Two schemes of macrophage administration were used: early and late. With the early administration, macrophages were injected on days 1, 5, 10, and 15 following the injection of EC cells at four sides of the tumor development area. With the late administration, macrophages were injected on days 10, 15, 20, and 25. At 15 and 30 days after the EC cell injection, the solid tumor was excised and its volume was measured. The effect of macrophage administration was assessed both qualitatively by visual and palpation characteristics of solid tumor and quantitatively by changes in the tumor volume compared with the group without the macrophage treatment. Results. M3 macrophages administered early after the onset of tumor development exerted a pronounced antitumor effect in vivo , which was significantly greater than the antitumor effect of the late administration of M3 macrophages. Conclusion. The observed significant inhibition of in vivo growth of solid carcinoma by M3 macrophages makes promising the development of a clinical version of the biotechnology for restriction of tumor growth by in vitro pre-programming of the antitumor, innate immune response.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Nanocurcumin: A Double-Edged Sword for Microcancers

2020 ◽  
Vol 26 (45) ◽  
pp. 5783-5792
Author(s):  
Kholood Abid Janjua ◽  
Adeeb Shehzad ◽  
Raheem Shahzad ◽  
Salman Ul Islam ◽  
Mazhar Ul Islam
Keyword(s):  
Intracellular Signaling ◽  
Dosage Forms ◽  
The Body ◽  
In Vivo Studies ◽  
Mrna Levels ◽  
Anticancer Activities ◽  
Road Map ◽  
Anticancer Effects

There is compelling evidence that drug molecules isolated from natural sources are hindered by low systemic bioavailability, poor absorption, and rapid elimination from the human body. Novel approaches are urgently needed that could enhance the retention time as well as the efficacy of natural products in the body. Among the various adopted approaches to meet this ever-increasing demand, nanoformulations show the most fascinating way of improving the bioavailability of dietary phytochemicals through modifying their pharmacokinetics and pharmacodynamics. Curcumin, a yellowish pigment isolated from dried ground rhizomes of turmeric, exhibits tremendous pharmacological effects, including anticancer activities. Several in vitro and in vivo studies have shown that curcumin mediates anticancer effects through the modulation (upregulation and/or downregulations) of several intracellular signaling pathways both at protein and mRNA levels. Scientists have introduced multiple modern techniques and novel dosage forms for enhancing the delivery, bioavailability, and efficacy of curcumin in the treatment of various malignancies. These novel dosage forms include nanoparticles, liposomes, micelles, phospholipids, and curcumin-encapsulated polymer nanoparticles. Nanocurcumin has shown improved anticancer effects compared to conventional curcumin formulations. This review discusses the underlying molecular mechanism of various nanoformulations of curcumin for the treatment of different cancers. We hope that this study will make a road map for preclinical and clinical investigations of cancer and recommend nano curcumin as a drug of choice for cancer therapy.

scholarly journals Functional identification of ygiP as a positive regulator of the ttdA-ttdB-ygjE operon

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2129-2135 ◽  
Author(s):  
Taku Oshima ◽  
Francis Biville
Keyword(s):  
Functional Characterization ◽  
Anaerobic Growth ◽  
Functional Identification ◽  
New Members ◽  
E Coli ◽  
Inner Membrane Protein ◽  
Tartrate Dehydratase

Functional characterization of unknown genes is currently a major task in biology. The search for gene function involves a combination of various in silico, in vitro and in vivo approaches. Available knowledge from the study of more than 21 LysR-type regulators in Escherichia coli has facilitated the classification of new members of the family. From sequence similarities and its location on the E. coli chromosome, it is suggested that ygiP encodes a lysR regulator controlling the expression of a neighbouring operon; this operon encodes the two subunits of tartrate dehydratase (TtdA, TtdB) and YgiE, an integral inner-membrane protein possibly involved in tartrate uptake. Expression of tartrate dehydratase, which converts tartrate to oxaloacetate, is required for anaerobic growth on glycerol as carbon source in the presence of tartrate. Here, it has been demonstrated that disruption of ygiP, ttdA or ygjE abolishes tartrate-dependent anaerobic growth on glycerol. It has also been shown that tartrate-dependent induction of the ttdA-ttdB-ygjE operon requires a functional YgiP.

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