scholarly journals Abnormal physiological properties and altered cell wall composition in Streptococcus pneumoniae grown in the presence of clavulanic acid.

1997 ◽  
Vol 41 (3) ◽  
pp. 504-510 ◽  
Author(s):  
A Severin ◽  
E Severina ◽  
A Tomasz
Keyword(s):  
Streptococcus Pneumoniae ◽  
High Performance ◽  
Biochemical Properties ◽  
Beta Lactam ◽  
Chromatography Analysis ◽  
Peptide Composition ◽  
Increased Sensitivity ◽  
Altered Cell ◽  
Quantitative Changes

Subinhibitory concentrations of clavulanate caused premature induction of stationary-phase autolysis, sensitization to lysozyme, and reductions in the MICs of deoxycholate and penicillin for Streptococcus pneumoniae. In the range of clavulanate concentrations producing these effects, this beta-lactam compound was selectively bound to PBP 3. Cell walls isolated from pneumococci grown in the presence of clavulanate showed increased sensitivity to the hydrolytic action of purified pneumococcal autolysin in vitro. High-performance liquid chromatography analysis of the peptidoglycan isolated from the clavulanate-grown cells showed major qualitative and quantitative changes in stem peptide composition, the most striking feature of which was the accumulation of peptide species carrying intact D-alanyl-D-alanine residues at the carboxy termini. The altered biological and biochemical properties of the clavulanate-grown pneumococci appear to be the consequences of suppressed D,D-carboxypeptidase activity.

scholarly journals In Vitro Propagation, Huperzine A Content and Antioxidant Activity of Three Genotypic Huperzia serrata

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1112
Author(s):  
Yan Yang ◽  
Liangfang Dai ◽  
Decai Wu ◽  
Limin Dong ◽  
Yisheng Tu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
High Performance ◽  
In Vitro Propagation ◽  
Huperzine A ◽  
Induction Medium ◽  
Naphthalene Acetic Acid ◽  
Regeneration Rate ◽  
Huperzia Serrata ◽  
Chromatography Analysis

Huperzia serrata is a traditional herb and endangered Chinese medicinal material, which has attracted much attention due to its production of Huperzine A (HupA). In vitro propagation of H. serrata is considered a new way to relieve the resource pressure of H. serrata. In this study, three different genotypic wild H. serrata were used for in vitro propagation. Then, the antioxidant activity and the content of HupA in the regenerated H. serrata were investigated. The results showed the survival rate of the explant was increased to 25.37% when using multiple sterilization processes. The best induction medium for H. serrata was the Schenk and Hildebrandt (SH) medium supplemented with 0.5 mg·L−1 Naphthalene acetic acid (NAA) and 0.1 mg·L−1 2,4-Dichlorophenoxyacetic acid (2,4-D), where the regeneration rate of the explant was to 57.04%. The best proliferation medium was the SH medium with NAA (1.0 mg·L−1), as the biomass of in vitro tissue increased 164.17 ± 0.41 times. High-performance liquid chromatography analysis showed that the in vitro culture of three genotypes could produce HupA and the content of HupA was 53.90–87.17 µg·g−1. The antioxidant experiment showed that the methanol extract of in vitro H. serrata had higher antioxidant activity than that of wild H. serrata. This study provides a reliable in vitro H. serrata culture protocol and laid an important foundation for the antioxidant capacity of the thallus and the content of HupA.

scholarly journals CHARACTERIZATION OF MOLLUSCICIDAL COMPONENT OF Moringa oleifera LEAF AND Momordica charantia FRUITS AND THEIR MODES OF ACTION IN SNAIL Lymnaea acuminata

2013 ◽  
Vol 55 (4) ◽  
pp. 251-259 ◽  
Author(s):  
Aparna Upadhyay ◽  
Vinay K. Singh ◽  
Dinesh K. Singh
Keyword(s):  
High Performance ◽  
Moringa Oleifera ◽  
Momordica Charantia ◽  
Chromatography Analysis ◽  
Leaf Powder ◽  
Fruit Powder ◽  
Lymnaea Acuminata ◽  
Molluscicidal Activity

SUMMARY The molluscicidal activity of the leaf powder of Moringa oleifera and lyophilized fruit powder of Momordica charantia against the snail Lymnaea acuminata was time and concentration dependent. M. oleifera leaf powder (96 h LC50: 197.59 ppm) was more toxic than M. charantia lyophilized fruit powder (96 h LC50: 318.29 ppm). The ethanolic extracts of M. oleifera leaf powder and Momordica charantia lyophilized fruit powder were more toxic than other organic solvent extracts. The 96 h LC50 of the column purified fraction of M. oleifera leaf powder was 22.52 ppm, while that of M. charantia lyophilized fruit powder was 6.21 ppm. Column, thin layer and high performance liquid chromatography analysis show that the active molluscicidal components in M. oleifera leaf powder and lyophilized fruit of M. charantia are benzylamine (96 h LC50: 2.3 ppm) and momordicine (96 h LC50: 1.2 ppm), respectively. Benzylamine and momordicine significantly inhibited, in vivo and in vitro, the acetylcholinesterase (AChE), acid and alkaline phosphatase (ACP/ALP) activities in the nervous tissues of L. acuminata. Inhibition of AChE, ACP and ALP activity in the nervous tissues of L. acuminata by benzylamine and momordicine may be responsible for the molluscicidal activity of M. oleifera and M. charantia fruits, respectively.

scholarly journals Genetic and Biochemical Characterization of the Streptococcus pneumoniae PcrA Helicase and Its Role in Plasmid Rolling Circle Replication

2006 ◽  
Vol 188 (21) ◽  
pp. 7416-7425 ◽  
Author(s):  
J. A. Ruiz-Masó ◽  
S. P. Anand ◽  
M. Espinosa ◽  
S. A. Khan ◽  
G. del Solar
Keyword(s):  
Streptococcus Pneumoniae ◽  
Biochemical Characterization ◽  
Essential Gene ◽  
Biochemical Properties ◽  
Dna Helicase ◽  
Rolling Circle Replication ◽  
Lower Efficiency ◽  
Rolling Circle ◽  
Rep Protein

ABSTRACT PcrA is a chromosomally encoded DNA helicase of gram-positive bacteria involved in replication of rolling circle replicating plasmids. Efficient interaction between PcrA and the plasmid-encoded replication initiator (Rep) protein is considered a requirement for the plasmid to replicate in a given host, and thus, the ability of a Rep protein to interact with heterologous PcrA helicases has been invoked as a determinant of plasmid promiscuity. We characterized transcription of the Streptococcus pneumoniae pcrA gene in its genetic context and studied the biochemical properties of its product, the PcrA Spn helicase. Transcription of the pneumococcal pcrA gene was directed by promoter Pa, consisting of an extended −10 box. Promoter Pa also accounted for expression of a second essential gene, radC, which was transcribed with much lower efficiency than pcrA, probably due to the presence of a terminator/attenuator sequence located between the two genes. PcrA Spn displayed single-stranded DNA-dependent ATPase activity. PcrA Spn showed 5′→3′ and 3′→5′ helicase activities and bound efficiently to partially duplex DNA containing a hairpin structure adjacent to a 6-nucleotide 5′ or 3′ single-stranded tail and one unpaired (flap) nucleotide in the complementary strand. PcrA Spn interacted specifically with RepC, the initiator of staphylococcal plasmid pT181. Although the pneumococcal helicase was able to initiate unwinding of the RepC-nicked pT181 DNA, it was much less processive in this activity than the cognate staphylococcal PcrA protein. Accordingly, PcrA Spn was inefficient in in vitro replication of pT181, and perhaps as a consequence, this plasmid could not be established in S. pneumoniae.

scholarly journals TolC-Dependent Exclusion of Porphyrins in Escherichia coli

2008 ◽  
Vol 190 (18) ◽  
pp. 6228-6233 ◽  
Author(s):  
Ryoko Tatsumi ◽  
Masaaki Wachi
Keyword(s):  
Escherichia Coli ◽  
Uv Irradiation ◽  
High Performance ◽  
Aminolevulinic Acid ◽  
Wild Type ◽  
E Coli ◽  
Chromatography Analysis ◽  
Increased Sensitivity ◽  
Mutant Cells ◽  
Reddish Brown Color

ABSTRACT We found that Escherichia coli tolC mutants showed increased sensitivity to 5-aminolevulinic acid (ALA), a precursor of porphyrins. The tolC mutant cells grown in the presence of ALA showed a reddish brown color under visible light and a strong red fluorescence under near-UV irradiation. Fluorescence spectrometry and high-performance liquid chromatography analysis showed that the tolC mutant cells grown in the presence of ALA accumulated a large amount of coproporphyrin(ogen) intracellularly. In contrast, the wild-type cells produced coproporphyrin extracellularly. The tolC mutant cells grown in the presence of ALA, which were capable of surviving in the dark, were killed by near-UV irradiation, suggesting that the intracellular coproporphyrin(ogen) renders these cells photosensitive. These results suggest that the TolC-dependent efflux system is involved in the exclusion of porphyrin(ogen)s in E. coli.

scholarly journals Novel Type of Heme-Dependent Oxygenase Catalyzes Oxidative Cleavage of Rubber (Poly-cis-1,4-Isoprene)

2004 ◽  
Vol 70 (12) ◽  
pp. 7388-7395 ◽  
Author(s):  
Reinhard Braaz ◽  
Peter Fischer ◽  
Dieter Jendrossek
Keyword(s):  
Natural Rubber ◽  
High Performance ◽  
Natural Rubber Latex ◽  
Culture Fluid ◽  
Oxidative Cleavage ◽  
Covalent Attachment ◽  
Rubber Latex ◽  
Chromatography Analysis ◽  
Cloned Gene

ABSTRACT An extracellular protein with strong absorption at 406 nm was purified from cell-free culture fluid of latex-grown Xanthomonas sp. strain 35Y. This protein was identical to the gene product of a recently characterized gene cloned from Xanthomonas sp., as revealed by determination of m/z values and sequencing of selected isolated peptides obtained after trypsin fingerprint analysis. The purified protein degraded both natural rubber latex and chemosynthetic poly(cis-1,4-isoprene) in vitro by oxidative cleavage of the double bonds of poly(cis-1,4-isoprene). 12-Oxo-4,8-dimethyltrideca-4,8-diene-1-al (m/z 236) was identified and unequivocally characterized as the major cleavage product, and there was a homologous series of minor metabolites that differed from the major degradation product only in the number of repetitive isoprene units between terminal functions, CHO-CH2— and —CH2-COCH3. An in vitro enzyme assay for oxidative rubber degradation was developed based on high-performance liquid chromatography analysis and spectroscopic detection of product carbonyl functions after derivatization with dinitrophenylhydrazone. Enzymatic cleavage of rubber by the purified protein was strictly dependent on the presence of oxygen; it did not require addition of any soluble cofactors or metal ions and was optimal around pH 7.0 at 40°C. Carbon monoxide and cyanide inhibited the reaction; addition of catalase had no effect, and peroxidase activity could not be detected. The purified protein was specific for natural rubber latex and chemosynthetic poly(cis-1,4-isoprene). Analysis of the amino acid sequence deduced from the cloned gene (roxA [rubber oxygenase]) revealed the presence of two heme-binding motifs (CXXCH) for covalent attachment of heme to the protein. Spectroscopic analysis confirmed the presence of heme, and approximately 2 mol of heme per mol of RoxA was found.

Quantitative high-performance liquid chromatography analysis of DNA oxidized in vitro and in vivo

1991 ◽  
Vol 196 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Krystyna Frenkel ◽  
Zhaojing Zhong ◽  
Huachen Wei ◽  
Jerzy Karkoszka ◽  
Umesh Patel ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Chromatography Analysis ◽  
Performance Liquid Chromatography Analysis

scholarly journals Improvement of Flavonoids in Lemon Seeds on Oxidative Damage of Human Embryonic Kidney 293T Cells Induced by H2O2

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Dingyi Yang ◽  
Yong Jiang ◽  
Yuqing Wang ◽  
Qianqian Lei ◽  
Xin Zhao ◽  
...  
Keyword(s):  
Survival Rate ◽  
Oxidative Damage ◽  
High Performance ◽  
Quantitative Polymerase Chain Reaction ◽  
Survival Rates ◽  
Human Embryonic Kidney ◽  
High Concentration ◽  
Stress Injury ◽  
Chromatography Analysis

In this study, flavonoids in lemon seeds (FLS) were used to assess its improvement on the oxidative damage of human embryonic kidney 293T cells (HEK 293T cells) induced by H2O2. In vitro experiments showed that the survival rates of HEK 293T cells treated with different flavonoid concentrations (50 μg/mL, 100 μg/mL, and 150 μg/mL) exceeded 95%, indicating no significant toxic effect. Compared with the normal group, H2O2 (0.3 mmol/L) resulted significantly in oxidative stress injury of HEK 293T cells. The survival rate of the damaged cells increased after treatment with flavonoids, and the survival rate of cells treated with a high concentration (150 μg/mL) of flavonoids was 76.2%. Flavonoids also effectively inhibited H2O2-induced apoptosis. At the same time, flavonoid treatment significantly reduced the malondialdehyde content in cells and increased the levels of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GSH-Px). Quantitative polymerase chain reaction (qPCR) and Western blot analysis also suggested that FLS upregulated mRNA and protein expressions of CAT, SOD (SOD1, SOD2), GSH (GSH1), and GSH-Px in H2O2-induced oxidative damage of HEK 293T cells. The high-performance liquid chromatography analysis demonstrated that FLS contained six compounds, including gallocatechin, caffeic acid, epicatechin, vitexin, quercetin, and hesperidin. FLS were proven to have a good antioxidant capacity in vitro and improve significantly the oxidative damage of HEK 293T cells induced by H2O2. The biological activity value warrants investigation in additional studies.

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