Role of oxygen radicals scavenging enzymes in the protoporphyrin induced photohemolysis

Reactive oxygen species (ROS) comprise the superoxide anion (O2·−), hydrogen peroxide (H2O2), hydroxyl radical (·OH), and singlet oxygen (1O2). ROS can damage a variety of macromolecules, including DNA, RNA, proteins, and lipids, and compromise cell viability. To prevent or reduce ROS-induced oxidative stress, bacteria utilize different ROS defense mechanisms, of which ROS scavenging enzymes, such as superoxide dismutases, catalases, and peroxidases, are the best characterized. Recently, evidence has been accumulating that some of the terminal oxidases in bacterial respiratory chains may also play a protective role against ROS. The present review covers this role of terminal oxidases in light of recent findings.

Download Full-text

Editorial [Hot Topic: Role of Oxygen Radicals in Inflammation and Allergy (Guest Editors: Masahiko Kato / Hirokazu Kimura)]

Current Drug Targets - Inflammation & Allergy ◽

10.2174/1568010054526250 ◽

2005 ◽

Vol 4 (4) ◽

pp. 487-487

Author(s):

M. Kato ◽

H. Kimura

Keyword(s):

Oxygen Radicals

Download Full-text

Alternative Pathway is Involved in Nitric Oxide-Enhanced Tolerance to Cadmium Stress in Barley Roots

Plants ◽

10.3390/plants8120557 ◽

2019 ◽

Vol 8 (12) ◽

pp. 557 ◽

Cited By ~ 5

Author(s):

Li He ◽

Xiaomin Wang ◽

Ruijun Feng ◽

Qiang He ◽

Shengwang Wang ◽

...

Keyword(s):

Stress Tolerance ◽

Alternative Pathway ◽

Cadmium Stress ◽

Cd Stress ◽

No Donor ◽

Ros Accumulation ◽

Mda Content ◽

Scavenging Enzymes ◽

Tolerance To Cadmium

Alternative pathway (AP) has been widely accepted to be involved in enhancing tolerance to various environmental stresses. In this study, the role of AP in response to cadmium (Cd) stress in two barley varieties, highland barley (Kunlun14) and barley (Ganpi6), was investigated. Results showed that the malondialdehyde (MDA) content and electrolyte leakage (EL) level under Cd stress increased in two barley varieties. The expressions of alternative oxidase (AOX) genes (mainly AOX1a), AP capacity (Valt), and AOX protein amount were clearly induced more in Kunlun14 under Cd stress, and these parameters were further enhanced by applying sodium nitroprussid (SNP, a NO donor). Moreover, H2O2 and O2− contents were raised in the Cd-treated roots of two barley varieties, but they were markedly relieved by exogenous SNP. However, this mitigating effect was aggravated by salicylhydroxamic acid (SHAM, an AOX inhibitor), suggesting that AP contributes to NO-enhanced Cd stress tolerance. Further study demonstrated that the effect of SHAM application on reactive oxygen species (ROS)-related scavenging enzymes and antioxidants was minimal. These observations showed that AP exerts an indispensable function in NO-enhanced Cd stress tolerance in two barley varieties. AP was mainly responsible for regulating the ROS accumulation to maintain the homeostasis of redox state.

Download Full-text