Guidelines for DNA recombination and repair studies: Cellular assays of DNA repair pathways.

Understanding the plasticity of genomes has been greatly aided by assays for recombination, repair and mutagenesis. These assays have been developed in microbial systems that provide the advantages of genetic and molecular reporters that can readily be manipulated. Cellular assays comprise genetic, molecular, and cytological reporters. The assays are powerful tools but each comes with its particular advantages and limitations. Here the most commonly used assays are reviewed, discussed, and presented as the guidelines for future studies.

Stress, itch and quality of life in chronic urticaria females.

INTRODUCTION: Chronic urticaria (CU) belongs to a group of psychodermatological disorders, thus stress can play a significant role in this dermatosis onset and/or exacerbation. On the other hand, the disease itself accompanied by itch, may be a source of distress and could worsen patients' quality of life (QoL). AIM: The first goal of our study was to compare stress intensity between CU subjects and the control group. The second aim was to investigate the relationships between disease-related parameters (CU severity, itch) and psychological variables (stress and QoL) in CU patients. MATERIAL AND METHODS: Forty-six female patients with CU participated in our study. Thirty-three healthy females constituted a control group. The following methods were applied: Urticaria Activity Score (UAS), Itch Severity Evaluation Questionnaire, Visual analogue scale (VAS), Social Readjustment Rating Scale (SRRS) and the Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL). RESULTS: Chronic urticaria patients demonstrated a significantly higher stress level in comparison to the control group (z = 2.699; p < 0.001). Regarding the total pruritus score, all CU-Q2oL dimensions were affected, except for subscale swelling/mental status. The strongest link was revealed between global itch and QoL subscale embarrassment (r = 0.51, p < 0.001). There were also statistically significant correlations between stress (VAS scale and SRRS) and QoL (all at least p < 0.05).Conclusions: Taking into account the significant pruritus contribution to QoL impairment, it would be worth employing itch-coping trainings in the CU group. As a consequence, feeling of self-control and self-efficacy could be enhanced, thus resulting in the well-being improvement.

Conjugates of abscisic acid, brassinosteroids, ethylene, gibberellins, and jasmonates.

Phytohormones, including auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberellins, and jasmonates, are involved in all aspects of plant growth, and developmental processes as well as environmental responses. However, our understanding of hormonal homeostasis is far from complete. Phytohormone conjugation is considered as a part of the mechanism to control cellular levels of these compounds. Active phytohormones are changed into multiple forms by acylation, esterification or glycosylation, for example. It seems that conjugated compounds could serve as pool of inactive phytohormones that can be converted to active forms by de-conjugation reactions. Some conjugates are thought to be temporary storage forms, from which free active hormones can be released after hydrolysis. It is also believed that conjugation serves functions, such as irreversible inactivation, transport, compartmentalization, and protection against degradation. The nature of abscisic acid, brassinosteroid, ethylene, gibberellin, and jasmonate conjugates is discussed.

Changes in growth, biochemical components, and antioxidant activity in aquatic plant Wolffia arrhiza (Lemnaceae) exposed to cadmium and lead.

The present study investigated the biochemical response of aquatic plant Wolffia arrhiza (Lemnaceae) treated with lead (Pb) and cadmium (Cd) at a range of concentrations from 1 to 1000 microM. W. arrhiza has been identified as good scavenger of heavy metals from aqueous solution. Pb and Cd accumulation was found to be increased in a concentration- and duration-dependent manner. However, the highest biosorption of heavy metals was found in plants exposed to low levels (10 microM) of Cd and Pb in the nutrient medium. In observing the response to heavy-metal stress, we noted inhibited plant growth and decreased photosynthetic pigments, monosaccharides, and proteins. In addition, Cd was found to be more toxic to plants than Pb. Heavy metals also induced oxidative damage as evidenced by increased lipid peroxidation and hydrogen peroxide levels. In contrast, the deleterious effects resulting from the cellular oxidative state can be alleviated by enzymatic (catalase, ascorbate peroxidase, nicotinamide dinucleotide [NADH] peroxidase) and nonenzymatic (ascorbate, glutathione) antioxidant mechanisms activated in W. arrhiza plants exposed to Cd and Pb, especially at 10 microM. These results suggest that W. arrhiza is a promising bioindicator of heavy-metal toxicity.

Conjugates of auxin and cytokinin.

Plant growth and developmental processes as well as environmental responses require the action and cross talk of phytohormones including auxins and cytokinins. Active phytohormones are changed into multiple forms by acylation, esterification or glycosylation, for example. It seems that conjugated compounds could serve as pool of inactive phytohormones that can be converted to active forms by de-conjugation reactions. The concept of reversible conjugation of auxins and cytokinins suggests that under changeable environmental, developmental or physiological conditions these compounds can be a source of free hormones. Phytohormones metabolism may result in a loss of activity and decrease the size of the bioactive pool. All metabolic steps are in principle irreversible, except for some processes such as the formation of ester, glucoside and amide conjugates, where the free compound can be liberated by enzymatic hydrolysis. The role, chemistry, synthesis and hydrolysis of conjugated forms of two classes of plant hormones are discussed.