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Effect of indole-3-acetic acid (IBA) on redox activity and proton extrusion in maize coleoptile segments

100%

Lekacz H. , Karcz W. , Burdach Z.

Acta Physiologiae Plantarum

2007

tom 29

nr 1 Suppl.

Polyphenol-protein complexes and their consequences for the redox activity, structure and function of honey. A current view and new hypothesis - a review

84%

Brudzynski K. , Maldonado-Alvarez L.

Polish Journal of Food and Nutrition Sciences

2015

tom 65

nr 2

There is increasing evidence that protein complexation by honey polyphenols is changing honey structure and function. This relatively less investigated filed of honey research is presented in a context of known mechanism of formation of the stable polyphenol-protein complexes in other foods. At a core of these interactions lies the ability of polyphenols to form non-covalent and covalent bonds with proteins leading to transient and/or irreversible complexes, respectively. Honey storage and thermal processing induces non-enzymatic oxidation of polyphenols to reactive quinones and enables them to form covalent bonds with proteins. In this short review, we present data from our laboratory on previously unrecognized types of protein-polyphenol complexes that differed in size, stoichiometry, and antioxidant capacities, and the implications they have to honey antioxidant and antibacterial activities. Our intent is to provide a current understanding of protein-polyphenol complexation in honey and also some new thoughts /hypotheses that can be useful in directing future research.

Wpływ IBA na aktywność redoksową i zmiany pH środowiska inkubacyjnego segmentów koleoptyli kukurydzy

67%

Lekacz H. , Karcz W. , Burdach Z.

Zeszyty Problemowe Postępów Nauk Rolniczych

2008

tom 524

Określono wpływ kwasu indolilo-3-masłowego (IBA) na aktywność redoksową, zmiany pH środowiska inkubacyjnego i tempo wzrostu segmentów koleoptyli kukurydzy (Zea mays L.). IBA stosowano w zakresie stężeń 10⁻⁶-10⁻⁴ mol·dm⁻³ . Doświadczenia przeprowadzano na 10 mm segmentach koleoptyli (pozbawionych pierwszego liścia) wycinanych z 4-dniowych etiolowanych siewek kukurydzy. Aktywność redoksową i zmiany pH środowiska mierzono synchronicznie zgodnie z metodą opisaną przez Carrasco-Luna i in. [1995]. Pomiarów dokonywano na segmentach z nieuszkodzoną jak i częściowo usuniętą kutikulą. Stwierdzono, że kwas indolilo-3-masłowy w stężeniu 10⁻⁵ mol·dm⁻³ stymulował aktywność redoksową, zakwaszanie środowiska inkubacyjnego i wzrost segmentów koleoptyli kukurydzy. Wykazano ponadto, że częściowe usunięcie kutikuli z segmentów koleoptyli wzmaga zarówno aktywność redoksową, jak i zakwaszenie środowiska inkubacyjnego.

Auxins are defined as organic substances that promote cell elongation when applied at low concentrations to the adequate plant tissue. Natural auxins IAA, IBA and 4-CL-IAA are found in plants as free acids and in the conjugated form. Indole-3-butyric acid was identified as a natural product in many plant species from maize (Zea mays) and pea (Pisum sativum) to Arabidopsis thaliana. IBA was definitively shown to occur naturally in plants in 1989 [Ludwig-Müller 2000]. Indole-3-butyric acid was tested at different concentrations ( 10⁻⁶-10⁻⁴ mol·dm⁻³) and times for their capacity to change redox activity and medium pH of maize coleoptile segments. The experiments were carried out with 10 mm long coleoptile segments cut from four-day-old etiolated maize seedlings. Before experiments the coleoptiles were abraded in an aqueous suspension of 1200 mesh SiC power. Redox activity and pH changes in incubation medium were measured simultaneously according to the method described by Carrasco-Luna et al. [1995]. Results indicate that both redox activity and pH changes in coleoptile segments dependent on concentrations of IBA and the time after its addition to the incubation medium. The maximum values of redox activity and pH changes of the incubation medium (expressed as A pH) were observed at 10⁻⁵ mol·dm⁻ ³ of IBA. Both the proton extrusion and the redox activity were strongly enhanced in the abraded coleoptile segments.

The effect of auxins [IAA and 4-Cl-IAA] on the redox activity and medium pH of Zea mays L. root segments

67%

Lekacz H. , Karcz W.

Cellular and Molecular Biology Letters

2006

tom 11

nr 3

Indole-3-acetic acid (IAA) and 4-chloroindole-3-acetic acid (4-Cl-IAA) were tested at different concentrations and times for their capacity to change the redox activity and medium pH of maize root segments. The dose-response surfaces (dose-response curves as a function of time) plotted for redox activity and changes in medium pH (expressed as ΔpH) had a similar shape for both auxins, but differed significantly at the optimal concentrations. With 4-Cl-IAA, the maximal values of redox activity and medium pH changes were observed at 10−10 M, which was a 100-fold lower concentration than with IAA. Correlations were observed between redox activity and medium pH changes at the optimal concentrations of both IAA and 4-Cl-IAA. The results are discussed herein, taking into account both the concentration of the auxins and the effects produced by them.