The effect of UV-B on Arabidopsis leaves depends on light conditions after treatment

BACKGROUND: Ultraviolet B (UV-B) irradiation can influence many cellular processes. Irradiation with high UV-B doses causes chlorophyll degradation, a decrease in the expression of genes associated with photosynthesis and its subsequent inhibition. On the other hand, sublethal doses of UV-B are used in post-harvest technology to prevent yellowing in storage. To address this inconsistency the effect of short, high-dose UV-B irradiation on detached Arabidopsis thaliana leaves was examined. RESULTS: Two different experimental models were used. After short treatment with a high dose of UV-B the Arabidopsis leaves were either put into darkness or exposed to constant light for up to 4 days. UV-B inhibited dark-induced chlorophyll degradation in Arabidopsis leaves in a dose-dependent manner. The expression of photosynthesis-related genes, chlorophyll content and photosynthetic efficiency were higher in UV-B -treated leaves left in darkness. UV-B treatment followed by constant light caused leaf yellowing and induced the expression of senescence-related genes. Irrespective of light treatment a high UV-B dose led to clearly visible cell death 3 days after irradiation. CONCLUSIONS: High doses of UV-B have opposing effects on leaves depending on their light status after UV treatment. In darkened leaves short UV-B treatment delays the appearance of senescence symptoms. When followed by light treatment, the same doses of UV-B result in chlorophyll degradation. This restricts the potential usability of UV treatment in postharvest technology to crops which are stored in darkness. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-015-0667-2) contains supplementary material, which is available to authorized users

Solutions of a quadratic Volterra-Stieltjes integral equation in the class of functions converging at infinity

The paper deals with the study of the existence of solutions of a quadratic integral equation of Volterra–Stieltjes type. We are looking for solutions in the class of real functions continuous and bounded on the real half-axis R+ and converging to proper limits at infinity. The quadratic integral equations considered in the paper contain, as special cases, a lot of nonlinear integral equations such as Volterra–Chandrasekhar or Volterra–Wiener–Hopf equations, for example. In our investigations we use the technique associated with measures of noncompactness and the Darbo fixed point theorem. Particularly, we utilize a measure of noncompactness related to the class of functions in which solutions of the integral equation in question are looking for

Evaluation of superoxide dismutase activity and its impact on semen quality parameters of infertile men.

The evaluation of superoxide dismutase (SOD) activity, as one of the most important antioxidative defence enzymes, in seminal plasma of patients consulting for male infertility was presented in the article. The study included also the determination of its influence on selected human semen quality parameters. The material represents semen samples obtained from 15 men, which were divided into two groups: Group I (n=10) including patients consulting for infertility and Group II (n=5) containing healthy sperm donors as a control. All of the semen samples were cryopreserved and stored in liquid nitrogen. The frozen samples were thawed at the same time and then SOD activity was determined spectrophotometrically. The analysis of the investigations results indicates a significantly lower semen SOD activity detected in oligoasthenozoospermic patients, comparing to the activity found in normospermic men. The study showed a positive correlation between SOD activity in seminal plasma and semen quality parameters--sperm concentration and overall motility, which are regarded as the most important for normal fertilizing ability of the spermatozoa. Significantly lower SOD activity in seminal plasma of infertile patients, comparing to healthy sperm donors, as well as positive correlation and beneficial impact of SOD activity on human semen quality parameters seem to confirm the observations, that decreased seminal plasma scavenger antioxidant capacity, particularly in form of low SOD activity, can be responsible for male infertility. This trial shows that SOD activity survey in seminal plasma could be a useful tool for determining sperm fertilization potential and could improve the diagnosis of male infertility

Characteristics of patients who underwent lower limb amputation due to critical limb ischemia – one center experience

Introduction. The aim of this study is to analyze the characteristics of patients in whom leg amputation was performed due to critical limb ischemia (CLI). Material and methods. Retrospective analysis of the characteristics of patients who underwent leg amputation between 2012 and 2014 in our center. Results. Between 2012 and 2014, 39 amputations of 37 limbs were performed on 32 patients treated due to CLI. Amputations amounted to 39/1282 (3.2%) of all vascular procedures performed on the lower limbs. They concerned, respectively: forefoot – 49%, calf – 15%, and thigh – 36%. In 85% of patients, the amputations were preceded by vascular procedures. The median length of time between the first revascularization procedure and amputation amounted to 99 ± 8-1088 days. Patients who underwent primary amputation (n = 6, 15%) compared to the individuals with secondary amputation were treated less frequently with aspirin (67% vs. 97%; p = 0.01) and statins (50% vs. 94%, p = 0.002). Patients who underwent amputation at thigh level compared with subjects with forefoot amputation were hospitalized for a significantly longer period of time, diagnosed more often with chronic heart failure (CHF) and chronic kidney disease (CKD), and were more often tobacco smokers. Conclusions. The main factors determining the need for amputation, its level and time between the first revascularization procedure and leg amputation were: the number of preceding procedures and stent implantations, comorbidity of CHF and CKD, smoking habit, inadequate pharmacotherapy (probably due to delayed diagnosis), severity of angiographic lesions, and higher MPV and INR values.Wstęp. Celem niniejszej pracy było przedstawienie charakterystyki pacjentów poddanych amputacji kończyn dolnych z powodu krytycznego niedokrwienia (CLI) w jednym ośrodku angiologicznym. Pacjenci i metody. W latach 2012-2014 w klinice wykonano 39 amputacji kończyn dolnych, na 37 kończynach, u 32 pacjentów leczonych z powodu CLI. Wyniki. Amputacje kończyn dolnych stanowiły 39/1282 (3%) wszystkich procedur naczyniowych na tętnicach kończyn dolnych. 49% amputacji dotyczyło przodostopia, 15% podudzia oraz 36% uda; 85% amputacji przeprowadzono na kończynach, które wcześniej były rewaskularyzowane. Średni czas między pierwszym zabie-giem naczyniowym a amputacją kończyny wynosił 99 ± 8-1088 dni. Pacjenci poddani pierwotnej amputacji rzadziej przyjmowali aspirynę (67% vs. 94%; p=0,01) oraz statyny (50% vs. 94%, p=0,002). Pacjenci z amputacją na udzie, w porównaniu z osobami z amputowanym przodostopiem, byli w związku z zabiegiem dłużej hospitalizowani, częściej mieli rozpoznaną przewlekłą niewydolność serca (PNS) i nerek (PNN), częściej palili i rzadziej przebyli udar mózgu. Nie stwierdzono różnic częstości występowania cukrzycy i dyslipidemii oraz nasilenia zmian angiograficznych. Zakres amputacji korelował m.in z wcześniejszą diagnozą PNS i PNN, przebyciem udaru mózgu, wartością MPV, INR i kreatyniny. Czas między wykonanym zabiegiem naczynio-wym a amputacją korelował znamiennie m.in. z: liczbą wykonanych zabiegów i stentów implantowanych podczas pierwszego zabiegu. Wnioski. 15% pacjentów z CLI trafiało do szpitala w stanie uniemożliwiającym podjęcie zabiegu rewaskula-ryzacyjnego. Czynnikami determinującymi konieczność amputacji i jej zakres były: liczba wcześniejszych zabiegów i implantacji stentów, współistniejące PNS i PNN, palenie tytoniu, nieadekwatna farmakoterapia (opóźnienie diagno-zy?), nasilenia zmian angiograficznych oraz wyższe wartości MPV i INR; nie wpływały na nią natomiast cukrzyca i dyslipidemia. in factors determining the need for amputation, its level and time between the first revascularization procedure and leg amputation were: the number of preceding procedures and stent implantations, comorbidity of CHF and CKD, smoking habit, inadequate pharmacotherapy (probably due to delayed diagnosis), severity of angiographic lesions, and higher MPV and INR values

Charakterystyka pacjentów poddanych amputacji z powodu przewlekłego niedokrwienia kończyn dolnych – doświadczenie jednego ośrodka

Introduction. The aim of this study is to analyze the characteristics of patients in whom leg amputation was performed due to critical limb ischemia (CLI).Material and methods. Retrospective analysis of the characteristics of patients who underwent leg amputation between 2012 and 2014 in our center.Results. Between 2012 and 2014, 39 amputations of 37 limbs were performed on 32 patients treated due to CLI. Amputations amounted to 39/1282 (3.2%) of all vascular procedures performed on the lower limbs. They concerned, respectively: forefoot – 49%, calf – 15%, and thigh – 36%. In 85% of patients, the amputations were preceded by vascular procedures. The median length of time between the first revascularization procedure and amputation amounted to 99 ± 8-1088 days. Patients who underwent primary amputation (n = 6, 15%) compared to the individuals with secondary amputation were treated less frequently with aspirin (67% vs. 97%; p = 0.01) and statins (50% vs. 94%, p = 0.002). Patients who underwent amputation at thigh level compared with subjects with forefoot amputation were hospitalized for a significantly longer period of time, diagnosed more often with chronic heart failure (CHF) and chronic kidney disease (CKD), and were more often tobacco smokers.Conclusions. The main factors determining the need for amputation, its level and time between the first revascularization procedure and leg amputation were: the number of preceding procedures and stent implantations, comorbidity of CHF and CKD, smoking habit, inadequate pharmacotherapy (probably due to delayed diagnosis), severity of angiographic lesions, and higher MPV and INR values.Wstęp. Celem niniejszej pracy było przedstawienie charakterystyki pacjentów poddanych amputacji kończyn dolnych z powodu krytycznego niedokrwienia (CLI) w jednym ośrodku angiologicznym.Pacjenci i metody. W latach 2012-2014 w klinice wykonano 39 amputacji kończyn dolnych, na 37 kończynach, u 32 pacjentów leczonych z powodu CLI.Wyniki. Amputacje kończyn dolnych stanowiły 39/1282 (3%) wszystkich procedur naczyniowych na tętnicach kończyn dolnych. 49% amputacji dotyczyło przodostopia, 15% podudzia oraz 36% uda; 85% amputacji przeprowadzono na kończynach, które wcześniej były rewaskularyzowane. Średni czas między pierwszym zabie-giem naczyniowym a amputacją kończyny wynosił 99 ± 8-1088 dni. Pacjenci poddani pierwotnej amputacji rzadziej przyjmowali aspirynę (67% vs. 94%; p=0,01) oraz statyny (50% vs. 94%, p=0,002). Pacjenci z amputacją na udzie, w porównaniu z osobami z amputowanym przodostopiem, byli w związku z zabiegiem dłużej hospitalizowani, częściej mieli rozpoznaną przewlekłą niewydolność serca (PNS) i nerek (PNN), częściej palili i rzadziej przebyli udar mózgu. Nie stwierdzono różnic częstości występowania cukrzycy i dyslipidemii oraz nasilenia zmian angiograficznych. Zakres amputacji korelował m.in z wcześniejszą diagnozą PNS i PNN, przebyciem udaru mózgu, wartością MPV, INR i kreatyniny. Czas między wykonanym zabiegiem naczynio-wym a amputacją korelował znamiennie m.in. z: liczbą wykonanych zabiegów i stentów implantowanych podczas pierwszego zabiegu.Wnioski. 15% pacjentów z CLI trafiało do szpitala w stanie uniemożliwiającym podjęcie zabiegu rewaskula-ryzacyjnego. Czynnikami determinującymi konieczność amputacji i jej zakres były: liczba wcześniejszych zabiegów i implantacji stentów, współistniejące PNS i PNN, palenie tytoniu, nieadekwatna farmakoterapia (opóźnienie diagno-zy?), nasilenia zmian angiograficznych oraz wyższe wartości MPV i INR; nie wpływały na nią natomiast cukrzyca i dyslipidemia.in factors determining the need for amputation, its level and time between the first revascularization procedure and leg amputation were: the number of preceding procedures and stent implantations, comorbidity of CHF and CKD, smoking habit, inadequate pharmacotherapy (probably due to delayed diagnosis), severity of angiographic lesions, and higher MPV and INR values

Pattern of antioxidant enzyme activities and hydrogen peroxide content during developmental stages of rhizogenesis from hypocotyl explants of Mesembryanthemum crystallinum L.

KEY MESSAGE: H(2)O(2)is necessary to elicit rhizogenic action of auxin. Activities of specific catalase and manganese superoxide dismutase forms mark roots development. ABSTRACT: Hypocotyl explants of Mesembryanthemum crystallinum regenerated roots on medium containing 2,4-dichlorophenoxyacetic acid. Explants became competent to respond to the rhizogenic action of auxin on day 3 of culture, when hydrogen peroxide content in cultured tissue was the highest. l-Ascorbic acid added to the medium at 5 μM lowered the H(2)O(2) level, inhibited rhizogenesis and induced non-regenerative callus, suggesting that certain level of H(2)O(2) is required to promote root initiation. Coincident with the onset of rhizogenic determination, meristemoids formed at the periphery of the hypocotyl stele and the activity of the manganese form of superoxide dismutase, MnSOD-2 was induced. Once induced, MnSOD-2 activity was maintained through the post-determination phase of rooting, involving root growth. MnSOD-2 activity was not found in non-rhizogenic explants maintained in the presence of AA. Analyses of the maximum photochemical efficiency of photosystem II and the oxygen uptake rate revealed that the explants were metabolically arrested during the predetermination stage of rhizogenesis. Respiratory and photosynthetic rates were high during root elongation and maturation. Changes in catalase and peroxidase activities correlated with fluctuations of endogenous H(2)O(2) content throughout rhizogenic culture. Expression of a specific CAT-2 form accompanied the post-determination stage of rooting and a high rate of carbohydrate metabolism during root growth. On the other hand, the occurrence of MnSOD-2 activity did not depend on the metabolic status of explants. The expression of MnSOD-2 activity throughout root development seems to relate it specifically to root metabolism and indicates it as a molecular marker of rhizogenesis in M. crystallinum

Blue-light-activated phototropin2 trafficking from the cytoplasm to Golgi/post-Golgi vesicles

Phototropins are plasma membrane-localized UVA/blue light photoreceptors which mediate phototropism, inhibition of primary hypocotyl elongation, leaf positioning, chloroplast movements, and stomatal opening. Blue light irradiation activates the C-terminal serine/threonine kinase domain of phototropin which autophosphorylates the receptor. Arabidopsis thaliana encodes two phototropins, phot1 and phot2. In response to blue light, phot1 moves from the plasma membrane into the cytosol and phot2 translocates to the Golgi complex. In this study the molecular mechanism and route of blue-light-induced phot2 trafficking are demonstrated. It is shown that Atphot2 behaves in a similar manner when expressed transiently under 35S or its native promoter. The phot2 kinase domain but not blue-light-mediated autophosphorylation is required for the receptor translocation. Using co-localization and western blotting, the receptor was shown to move from the cytoplasm to the Golgi complex, and then to the post-Golgi structures. The results were confirmed by brefeldin A (an inhibitor of the secretory pathway) which disrupted phot2 trafficking. An association was observed between phot2 and the light chain2 of clathrin via bimolecular fluorescence complementation. The fluorescence was observed at the plasma membrane. The results were confirmed using co-immunoprecipitation. However, tyrphostin23 (an inhibitor of clathrin-mediated endocytosis) and wortmannin (a suppressor of receptor endocytosis) were not able to block phot2 trafficking, indicating no involvement of receptor endocytosis in the formation of phot2 punctuate structures. Protein turnover studies indicated that the receptor was continuously degraded in both darkness and blue light. The degradation of phot2 proceeded via a transport route different from translocation to the Golgi complex