Effect of Cassava Processing Effluents on Antioxidant Enzyme Activities in Allium cepa L.

The underlying principle of the biomarker approach is to analyse the physiological and/or biochemical response of an organism exposed to an environmental pollutant. Onion bulbs were exposed directly in 0%, 0.2%, 0.4%, 0.8% 1%, 2%, 3%, 4% and 5% concentrations (v/v) to each effluent of three popular Nigerian cassava meals: garri, lafun and akpu for 96 hours. The root growth of the onion bulb and superoxide dismutase (SOD), and catalase (CAT), activities were measured. At 96 h, the root tips showed concentration-dependent growth retardation in all the effluents with EC50 values of 1.5%, 2.5% and 3.5% for garri, lafun and akpu effluents respectively while total phytotoxic effects was induced at higher effluent concentration. The physico-chemical analyses showed that the effluents were highly acidic and contained significant (p<0.05) amounts of cyanide and heavy metals compared to the control. The effluents induced increased malondialdehyde (MDA) levels and accelerated SOD activity at low concentrations but decreased after attaining maximum activity in garri effluent at 1%. Catalase was inconsistent; however, a drastic decrease in activity was recorded at the same effluent concentration. Lafun and akpu induced similar increases in antioxidant enzymic activity up till 2% effluent concentration after which steep decline set in

Karyopherins regulate nuclear pore complex barrier and transport function

Nucleocytoplasmic transport is sustained by karyopherins (Kaps) and a Ran guanosine triphosphate (RanGTP) gradient that imports nuclear localization signal (NLS)–specific cargoes (NLS-cargoes) into the nucleus. However, how nuclear pore complex (NPC) barrier selectivity, Kap traffic, and NLS-cargo release are systematically linked and simultaneously regulated remains incoherent. In this study, we show that Kap α facilitates Kap β 1 turnover and occupancy at the NPC in a RanGTP-dependent manner that is directly coupled to NLS-cargo release and NPC barrier function. This is underpinned by the binding affinity of Kap β 1 to phenylalanine–glycine nucleoporins (FG Nups), which is comparable with RanGTP·Kap β 1, but stronger for Kap α ·Kap β 1. On this basis, RanGTP is ineffective at releasing standalone Kap β 1 from NPCs. Depleting Kap α ·Kap β 1 by RanGTP further abrogates NPC barrier function, whereas adding back Kap β 1 rescues it while Kap β 1 turnover softens it. Therefore, the FG Nups are necessary but insufficient for NPC barrier function. We conclude that Kaps constitute integral constituents of the NPC whose barrier, transport, and cargo release functionalities establish a continuum under a mechanism of Kap-centric control

核膜孔複合体を介したカリオフェリン依存的分子輸送機構の速度論的解析

Authors are permitted to post the MBoC PDF of their articles (and/or supplemental material) on their personal websites or in an online institutional repository provided there appears always the proper citation of the manuscript in MBoC and a link to the original publication of the manuscript in MBoC (http://www.molbiolcell.org/site/misc/ifora.xhtml)京都大学0048新制・課程博士博士(生命科学)甲第19869号生博第350号新制||生||46(附属図書館)32905京都大学大学院生命科学研究科統合生命科学専攻(主査)教授 河内 孝之, 教授 藤田 尚志, 教授 永尾 雅哉学位規則第4条第1項該当Doctor of Philosophy in Life SciencesKyoto UniversityDFA

Dissecting in vivo steady-state dynamics of karyopherin-dependent nuclear transport

Karyopherin-dependent molecular transport through the nuclear pore complex is maintained by constant recycling pathways of karyopherins coupled with the Ran-dependent cargo catch-and-release mechanism. Although many studies have revealed the bidirectional dynamics of karyopherins, the entire kinetics of the steady-state dynamics of karyopherin and cargo is still not fully understood. In this study, we used fluorescence recovery after photobleaching and fluorescence loss in photobleaching on live cells to provide convincing in vivo proof that karyopherin-mediated nucleocytoplasmic transport of cargoes is bidirectional. Continuous photobleaching of the cytoplasm of live cells expressing NLS cargoes led to progressive decrease of nuclear fluorescence signals. In addition, experimentally obtained kinetic parameters of karyopherin complexes were used to establish a kinetic model to explain the entire cargo import and export transport cycles facilitated by importin β. The results strongly indicate that constant shuttling of karyopherins, either free or bound to cargo, ensures proper balancing of nucleocytoplasmic distribution of cargoes and establishes effective regulation of cargo dynamics by RanGTP

Effect of Cassava Processing Effluents on Antioxidant Enzyme Activities in Allium cepa L.

The underlying principle of the biomarker approach is to analyse the physiological and/or biochemical response of an organism exposed to an environmental pollutant. Onion bulbs were exposed directly in 0%, 0.2%, 0.4%, 0.8% 1%, 2%, 3%, 4% and 5% concentrations (v/v) to each effluent of three popular Nigerian cassava meals: garri, lafun and akpu for 96 hours. The root growth of the onion bulb and superoxide dismutase (SOD), and catalase (CAT), activities were measured. At 96 h, the root tips showed concentration-dependent growth retardation in all the effluents with EC50 values of 1.5%, 2.5% and 3.5% for garri, lafun and akpu effluents respectively while total phytotoxic effects was induced at higher effluent concentration. The physico-chemical analyses showed that the effluents were highly acidic and contained significant (p<0.05) amounts of cyanide and heavy metals compared to the control. The effluents induced increased malondialdehyde (MDA) levels and accelerated SOD activity at low concentrations but decreased after attaining maximum activity in garri effluent at 1%. Catalase was inconsistent; however, a drastic decrease in activity was recorded at the same effluent concentration. Lafun and akpu induced similar increases in antioxidant enzymic activity up till 2% effluent concentration after which steep decline set in

Effect of Cassava Processing Effluents on Antioxidant Enzyme Activities in Allium cepa L.

The underlying principle of the biomarker approach is to analyse the physiological and/or biochemical response of an organism exposed to an environmental pollutant. Onion bulbs were exposed directly in 0%, 0.2%, 0.4%, 0.8% 1%, 2%, 3%, 4% and 5% concentrations (v/v) to each effluent of three popular Nigerian cassava meals: garri, lafun and akpu for 96 hours. The root growth of the onion bulb and superoxide dismutase (SOD), and catalase (CAT), activities were measured. At 96 h, the root tips showed concentration-dependent growth retardation in all the effluents with EC50 values of 1.5%, 2.5% and 3.5% for garri, lafun and akpu effluents respectively while total phytotoxic effects was induced at higher effluent concentration. The physico-chemical analyses showed that the effluents were highly acidic and contained significant (p<0.05) amounts of cyanide and heavy metals compared to the control. The effluents induced increased malondialdehyde (MDA) levels and accelerated SOD activity at low concentrations but decreased after attaining maximum activity in garri effluent at 1%. Catalase was inconsistent; however, a drastic decrease in activity was recorded at the same effluent concentration. Lafun and akpu induced similar increases in antioxidant enzymic activity up till 2% effluent concentration after which steep decline set in