BACKGROUND The use of ultraviolet (UV)-B irradiation after alloantigen immunization is unknown because previous studies focused on UV-B irradiation before immunization. Here, we investigated immunosuppressive effects induced by UV-B irradiation after immunization, and examined the phenotype of induced regulatory T cells and the possible mechanism of induction. MATERIAL AND METHODS B6 mice (H-...

The impact of ambient ultraviolet (UV)-B radiation on the endemic bryophyte, Grimmia antarctici, was studied over 14 months in East Antarctica. Over recent decades, Antarctic plants have been exposed to the largest relative increase in UV-B exposure as a result of ozone depletion. We investigated the effect of reduced UV and visible radiation on the pigment concentrations, surface reflectance a...

Enhanced ultraviolet-B (UV-B) radiation and elevated tropospheric ozone alone may inhibit the growth of agricultural crops. However, research regarding their combined effects on growth and biochemical properties of roots is still scarce. Using open top chambers, we monitored the response of growth, secondary metabolites, endogenous hormones and enzyme activities of soybean roots to elevated O3 ...

Plants are constantly exposed to a wide range of environmental genotoxic stress factors including obligatory exposure to UV radiation in sunlight. Here, we report the functional characterization of a DNA repair protein, AtPolλ, a homolog of mammalian DNA polymerase λ in Arabidopsis, in relation to its role in repair of UV-B-induced DNA damage during early stages of seedling development. The abu...

Gene expression is known to change in response to UV-B radiation. In this paper, we have investigated three factors in Arabidopsis leaves that are likely to influence these changes: development, protective pigments and the 'chloroplast signal'. During late leaf development the major change in pigment composition, after exposure to UV-B radiation, is an increase in UV-absorbing pigments. Chl and...

Two groups of 30 dorsally shaved opossums (Monodelphis domestica) were exposed three times per week for 81 weeks to 250 J/m2 of UV radiation from FS40 sunlamps (approximately 150 J/m2 of UV radiation B; UV-B), or to 2.5 x 10(4) J/m2 of UV radiation A (UV-A) from filtered F40BLB fluorescent lamps (black lights). Animals were monitored for the appearance of nonmelanoma skin tumors (NMSTs) and mel...

The ecosystems of Tierra del Fuego (in southern Patagonia, Argentina) are seasonally exposed to elevated levels of ultraviolet-B radiation (UV-B: 280–315 nm), due to the passage of the ‘ozone hole’ over this region. In the experiments reported in this article the effects of solar UV-B and UV-A (315–400 nm) on two UV-B defence-related processes: the accumulation of protective UV-absorbing compou...

Long-term outdoor experiments were conducted to investigate the effects of elevated ultraviolet-B (UV-B, 280-320 nm) radiation on secondary metabolites (phenolics and terpenoids) and the main soluble sugars (sucrose, raffinose and glucose) in the bark of silver birch (Betula pendula Roth) saplings. Saplings were exposed to a constant 50% increase in erythemal UV irradiance (UV-B(CIE); based on ...

Tierra del Fuego, Argentina (551S), receives increased solar ultraviolet-B radiation (UV-B) as a result of Antarctic stratospheric ozone depletion. We conducted a field study to examine direct and indirect effects of solar UV-B radiation on decomposition of Gunnera magellanica, a native perennial herb, and on the native community of decomposer organisms. In general, indirect effects of UV-B mos...