Achieving 0.2% Relative Expanded Uncertainty in Ion Chromatography Analysis Using a High-Performance Methodology

2011 ◽  
Vol 83 (10) ◽  
pp. 3801-3807 ◽  
Author(s):  
Ryan G. Brennan ◽  
Therese A. Butler ◽  
Michael R. Winchester
Keyword(s):  
Ion Chromatography ◽  
High Performance ◽  
Expanded Uncertainty ◽  
Relative Expanded Uncertainty ◽  
Chromatography Analysis

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 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 Histological Characterization of Resistance to Different Root-Knot Nematode Species Related to Phenolics Accumulation in Capsicum annuum

2005 ◽  
Vol 95 (2) ◽  
pp. 158-165 ◽  
Author(s):  
A. Pegard ◽  
G. Brizzard ◽  
A. Fazari ◽  
O. Soucaze ◽  
P. Abad ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Capsicum Annuum ◽  
High Performance ◽  
Nematode Species ◽  
Susceptible Cultivar ◽  
Resistant Line ◽  
Root Knot Nematode ◽  
Resistance Response ◽  
Root Knot Nematodes ◽  
Chromatography Analysis

In the pepper Capsicum annuum CM334, which is used by breeders as a source of resistance to Phytophthora spp. and potyviruses, a resistance gene entirely suppresses reproduction of the root-knot nematode (Meloidogyne spp.). The current study compared the histological responses of this resistant line and a susceptible cultivar to infection with the three most damaging root-knot nematodes: M. arenaria, M. incognita, or M. javanica. Resistance of CM334 to root-knot nematodes was associated with unidentified factors that limited nematode penetration and with post-penetration biochemical responses, including the hypersensitive response, which apparently blocked nematode migration and thereby prevented juvenile development and reproduction. High-performance liquid chromatography analysis suggested that phenolic compounds, especially chlorogenic acid, may be involved in CM334 resistance. The response to infection in the resistant line varied with root-knot nematode species and was correlated with nematode behavior and pathogenicity in the susceptible cultivar: nematode species that quickly reached the vascular cylinder and initiated feeding sites in the susceptible cultivar were quickly recognized in CM334 and stopped in the epidermis or cortex. After comparing our data with those from other resistant pepper lines, we suggest that timing of the resistance response and the mechanism of resistance vary with plant genotype, resistance gene, and root-knot nematode species.

scholarly journals The PKS4 Gene of Fusarium graminearum Is Essential for Zearalenone Production

2006 ◽  
Vol 72 (6) ◽  
pp. 3924-3932 ◽  
Author(s):  
Erik Lys�e ◽  
Sonja S. Klemsdal ◽  
Karen R. Bone ◽  
Rasmus J. N. Frandsen ◽  
Thomas Johansen ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
High Performance ◽  
Polyketide Synthase ◽  
Wild Type ◽  
Root Infection ◽  
Enoyl Reductase ◽  
Transformation Protocol ◽  
Chromatography Analysis ◽  
In The Wild ◽  
High Level

ABSTRACT Zearalenones are produced by several Fusarium species and can cause reproductive problems in animals. Some aurofusarin mutants of Fusarium pseudograminearum produce elevated levels of zearalenone (ZON), one of the estrogenic mycotoxins comprising the zearalenones. An analysis of transcripts from polyketide synthase genes identified in the Fusarium graminearum database was carried out for these mutants. PKS4 was the only gene with an enoyl reductase domain that had a higher level of transcription in the aurofusarin mutants than in the wild type. An Agrobacterium tumefaciens-mediated transformation protocol was used to replace the central part of the PKS4 gene with a hygB resistance gene through double homologous recombination in an F. graminearum strain producing a high level of ZON. PCR and Southern analysis of transformants were used to identify isolates with single insertional replacements of PKS4. High-performance liquid chromatography analysis showed that the PKS4 replacement mutant did not produce ZON. Thus, PKS4 encodes an enzyme required for the production of ZON in F. graminearum. Barley root infection studies revealed no alteration in the pathogenicity of the PKS4 mutant compared to the pathogenicity of the wild type. The expression of PKS13, which is located in the same cluster as PKS4, decreased dramatically in the mutant, while transcription of PKS4 was unchanged. This differential expression may indicate that ZON or its derivatives do not regulate expression of PKS4 and that the PKS4-encoded protein or its product stimulates expression of PKS13. Furthermore, both the lack of aurofusarin and ZON influenced the expression of other polyketide synthases, demonstrating that one polyketide can influence the expression of others.

High Performance Ion Chromatography Determination of Total Sulfites in Foodstuffs

1994 ◽  
Vol 17 (2) ◽  
pp. 447-456 ◽  
Author(s):  
E. Ruiz ◽  
M. I. Santillana ◽  
M. De Alba ◽  
M. T. Neeto ◽  
S. Garcia-Castellano
Keyword(s):  
Ion Chromatography ◽  
High Performance

scholarly journals Allelopathy and Allelochemicals of Eragrostis plana (Poaceae) and its Relation with Phenology and Nitrogen Fertilization

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
K. CECCHIN ◽  
A. FAVARETTO ◽  
S.M. SCHEFFER-BASSO ◽  
C.D. BERTOL ◽  
S.O. CHINI
Keyword(s):  
Nitrogen Fertilization ◽  
High Performance ◽  
Phenological Stage ◽  
Flowering Stage ◽  
Chromatography Analysis ◽  
Allelopathic Activity ◽  
Aerial Parts ◽  
Main Plot ◽  
Chemical Attributes ◽  
Plot Design

ABSTRACT This study was conducted in order to verify if the phenological stage and the nitrogen fertilization interfere in the allelopathic activity and in the concentration of potentially allelopathic phenolic compounds of tough lovegrass (Eragrostis plana). The assay consisted of a bifactor 3 (0.100 and 200 kg N ha-1) x 2 (harvested in vegetative and reproductive stages), in a split plot design. The N doses constituted the main plot and the phenological stage during the harvest the subplots, resulting in six treatments. The tough lovegrass plants derived from each of the treatments were subjected to allelopathy bioassays, in which aqueous extracts of the aerial parts were applied to lettuce cypselae (Lactuca sativa) and to phytochemicals tests when ethanolic extracts were used, with subsequent partition with ethyl acetate, followed by a high-performance liquid chromatography analysis. There was nitrogen x phenological stage interaction on biological and chemical attributes. The allelopathic extracts were, in descending order of inhibition of germination, those from plants harvested at the vegetative stage and fertilized with 100 kg N and at the flowering stage with 200 kg N, which showed the highest catechin concentrations. The caffeic, ferulic, p-coumaric and vanillic acids were in a higher concentration in flowered and fertilized plants with 0 or 200 kg N. The management of the nitrogen fertilization and the harvesting age influence the allelopathic activity and the phytochemical composition of tough lovegrass.

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