Strong antioxidant capacity of horseradish hairy root cultures under arsenic stress indicates the possible use of Armoracia rusticana plants for phytoremediation.

The potential contamination of the food chain is the most important aspect of arsenic (As) pollution, since it is highly toxic to all organisms. Thus, the search for As hyperaccumulators suitable to remove As from contaminated soils appears to be a vital task. Horseradish (Armoracia rusticana), a crop plant with a high potential to accumulate heavy metals, can also serve to study the physiological processes that accompany arsenic stress. The significant adverse effect caused by arsenic exposure is an oxidative stress. Plants have developed a highly organized system to quench free radicals, which includes the action of both enzymatic and non-enzymatic quenching. Saccharides are proposed to possess outstanding antioxidant activity in vitro, and thus, they are likely to effectively quench free radicals also in plant tissues. In this study, root cultures (hairy root type) of horseradish were grown in vitro on media with different concentrations of arsenic (5-60 µg l-1). Arsenic slowed down the growth, nevertheless up to three-fold biomass increase was achieved at the highest dose. Moreover, root tissues were able to remove as much as 75% of arsenic from the cultivation medium within 7 days. We also evaluated diverse oxidative-stress-related features: contents of reactive oxygen species, the activities of key antioxidant enzymes, and the contents of important antioxidant molecules, such as glutathione, proline, phenolic compounds and non-structural carbohydrates. At all arsenic treatments, we observed a significant proline content increase and enhanced antioxidant enzymes (peroxidase, catalase and glutathione-S-transpherase) activities peaking, however, at different doses. Soluble carbohydrates contents also significantly increased after 7-day treatment a then decreased nearly to the original levels. This study points to efficient antioxidant system of horseradish hairy roots enabling good growth and substantial As accumulation even under high As exposure. Providing that horseradish shares these important features with this model system, we could propose that horseradish is a promising candidate to exploit in arsenic phytoremediation.

[Digital images of the retinal nerve fiber layer in healthy eye and in glaucoma]. / Digitální snímky vrstvy nervových vláken sítnice u zdravého oka a u glaukomu.

The authors describe the procedure how to take pictures of the retinal nerve fiber layer with the fundus camera CANON CF-60UV connected to the digital camera EOS 20D. They attach practical instructions how to modify taken digital pictures with the Photoshop CS2 software, to make the nerve fiber layer and its losses more visible. They present modified pictures of the nerve fiber layer in healthy eye and in glaucoma where the losses are compared to the scotomas in the visual field.

[Subjective examination of the nerve fiber layer of the retina and its evaluation in a healthy eye and in glaucoma]. / Subjektivni vysetrení vrstvy nervových vláken sítnice a její hodnocení u zdravého oka a u glaukomu.

The authors describe the advantage of subjective examination of the nerve fiber layer in everyday outpatient praxis of the ophthalmologist. The objective examination of the nerve fiber layer is performed on specialized clinics by means of expensive instruments as are OCT, GDX or HRT. Every ophthalmologist may analyze the retinal nerve fiber layer subjectively with the basic equipment of the praxis. The aim of this paper is to present a recommendation how to expand the routine technique of the direct ophthalmoscope examination and biomicroscopy examination on the slit lamp, to make possible to observe subjectively the retinal nerve fiber layer and to distinguish its changes in glaucoma.