Elements not usually included in culture medium formulations, such as selenium (Se), may have beneficial effects on micropropagated plants. We evaluated the effects of Se on the physiological and anatomical responses of Alcantarea imperialis during in vitro culture. Plants were cultured in a medium containing a gradient of Se concentrations (0, 4, 8, 16, or 32 µM Se). After 56 d, the growth traits, chlorophyll a fluorescence, and root and leaf anatomy were analyzed. The fresh mass declined at the highest Se concentration. Higher Se concentrations induced bigger stomata, while the stomatal density decreased. Plants cultured with Se had improved PSII and PSI electron transport. This led to higher values of the total performance index. Thus, Se-induced plants showed a higher electron transport dynamics and energy conservation from water to PSI and developed anatomical traits that can favor tolerance to water deficit.
Alterations in photosynthetic performance of lutein-deficient mutant lut2 and wild type (wt) of Arabidopsis thaliana were followed after treatment with low temperature and high light for 6 d. The obtained results indicated lower electrolyte leakage, lower excitation pressure, and higher actual photochemical efficiency of PSII in lut2 plants exposed to combined stress compared to wt plants. This implies that lut2 is less susceptible to the applied stress conditions. The observed lower values of quantum efficiency of nonphotochemical quenching and energy-dependent component of nonphotochemical quenching in lut2 suggest that nonphotochemical quenching mechanism(s) localized within LHCII could not be involved in the acquisition of higher stress tolerance of lut2 and alternatives to nonphotochemical quenching mechanisms are involved for dissipation of excess absorbed light. We suggest that the observed enhanced capacity for cyclic electron flow and the higher oxidation state of P700 (P700+), which suggests PSI-dependent energy quenching in lut2 plants may serve as efficient photoprotective mechanisms, thus explaining the lower susceptibility of lut2 to the combined stress treatments.
This study aimed to determine the photosynthetic performance and differences in chlorophyll fluorescence (ChlF) parameters between Eulophia dentata and its companion species Bletilla formosana and Saccharum spontaneum when subjected to different photosynthetic photon flux density (PPFDs). Leaf surfaces were then illuminated with 50, 100 (low PPFDs), 300, 500, 800 (moderate PPFDs); 1,000; 1,500; and 2,000 (high PPFDs) μmol m-2.s-1, and the ChlF parameters were measured during the whole process. Increasing nonphotochemical quenching of ChlF and decreasing potential quantum efficiency of PSII, actual quantum efficiency of PSII, and quantum efficiency ratio of PSII in dark recovery from 0-60 min were observed in all leaves. A significant and negative relationship was detected between energy-dependent quenching (qE) and photoinhibition percent in three species under specific PPFD conditions, whereas a significant and positive relationship was detected between photoinhibitory quenching (qI) and photoinhibition percent. The qE and qI can be easily measured in the field and provide useful ecological indexes for E. dentata species restoration, habitat creation, and monitoring.
Selected light wavebands promote plant development and/or the biosynthesis of targeted metabolites. This work offers new insights on the effects of red (R), green (G), blue (B), and white (W - R:G:B; 1:1:1) LED light supplementation on physiochemical traits of strawberry leaves. Gas exchange and chlorophyll fluorescence parameters, photosynthetic pigments, and superoxide anion (*O2-) content were analysed in plants grown for 1 (T1) and 17 (T17) d with light supplementations. At T1, light supplementations resulted in the enhancement of the de-epoxidation state of xanthophylls and nonphotochemical quenching, but no changes were observed in maximal photosynthetic rate (PNmax), irrespective of light spectra. At T17, xanthophyll contents remained higher only in R-supplemented plants. Overall, W light resulted in higher photosynthesis, whilst R and B light depressed PNmax values and promoted *O2- formation at T17. G light did not induce variations in photosynthetic traits nor induced oxidative stress at both T1 and T17.
Hybrid photoelectrodes containing biological pigment-protein complexes can be used for environmentally friendly solar energy conversion, herbicide detection, and other applications. The total number of scientific publications on hybrid bio-based devices has grown rapidly over the past decades. Particular attention is paid to the integration of the complexes of PSII into photoelectrochemical devices. A notable feature of these complexes from a practical point of view is their ability to obtain electrons from abundant water. The utilization or imitation of the PSII functionality seems promising for all of the following: generating photoelectricity, photo-producing hydrogen, and detecting herbicides. This review summarizes recent advances in the development of hybrid devices based on PSII. In a brief historical review, we also highlighted the use of quinone-type bacterial reaction centers in hybrid devices. These proteins are the first from which the photoelectricity signal was detected. The photocurrent in these first systems, developed in the 70s-80s, was about 1 nA cm-2. In the latest work, by Güzel et al. (2020), a stable current of about 888 μA cm-2 as achieved in a PSII-based solar cell. The present review is inspired by this impressive progress. The advantages, disadvantages, and future endeavors of PSII-inspired bio-photovoltaic devices are also presented.
Extracellular vesicles are small membrane particles (30-1000 nm) released by Bacteria, Eukaryotes and Archaea. They have been shown to play an important role in intracellular and intercellular communication, within and between kingdoms via transport of bioactive molecules. Thus, they can be involved in altering gene expression and regulation of physiological and pathological processes of the recipient. Their unique properties make extracellular vesicles a perfect candidate vector for targeted drug delivery or a biomarker. For a long time, animal and mainly mammal extracellular vesicles have been used in research. But for plants, there had been speculations about the existence of nanovesicles due to the presence of a cell wall. Today, awareness of plant extracellular vesicles is on the rise and their research has proved they have various functions, such as protein secretion, transport of bioactive molecules or defense against pathogens. Further potential of plant extracellular vesicles is stressed in this review.
Plant volatiles can synergize the response to moth pheromone. Synthetic pheromone analogs, in turn, have the opposite effect in reducing pheromone attractiveness. To determine how these two types of stimuli interact and influence male moth behaviour, we performed wind tunnel experiments on the grapevine moth, Lobesia botrana. We noticed that a blend of host plant volatiles [(E)-β-caryophyllene, 1-hexanol, (Z)-3-hexenyl acetate and 1-octen-3-ol in a 100:20:10:5 ratio] significantly increased the response of males to an optimized blend of sex pheromone [(7E,9Z)-dodeca-7,9-dienyl acetate (E7,Z9-12:Ac), (7E,9Z)- dodeca-7,9-dienol (E7,Z9-12:OH) and (Z)-9-dodecenyl acetate (Z9-12:Ac)] in a 100:10:2 ratio. However, the response of males to the natural attractant was significantly reduced by two analogs [(9E,11Z)-tetradeca-9,11-dien-2-one (MK 2) and [(9E,11Z)-1,1,1-trifluoro-tetradeca-9,11-dien-2-one (TFMK 3)], of the major component of the sex pheromone of the insect (E7,Z9-12:Ac). When both stimuli were tested on males at pheromone:analog:plant volatile blend 1:100:1000 ratio, the plant blend offset the inhibitory effect induced by TFMK 3 but not that of MK 2. Our results show for the first time that under laboratory conditions plant volatiles can prevent inhibition by a pheromone analog., Albert Sans, Miguel Morán, Magí Riba, Ángel Guerrero, Jaume Roig, César Gemeno., and Obsahuje bibliografii
Peripheral insulin resistance is associated with decreasing adiponectin and increasing leptin plasma levels, and also with cognitive decline. The effects of adipokines on brain function have been published from both animal and human studies. In particular, the influence of leptin and adiponectin on the development of Alzheimer’s disease (AD) has been extensively investigated. However, the association between adipsin and AD is as yet unknown. In 37 patients with AD and 65 controls that followed the same study protocol, we tested whether adiponectin, leptin, and adipsin could be used as biomarkers in the early stages of AD. In contrast with conclusions of cognition studies in insulin resistant states, our study found a correlation of impaired neuropsychological performance with increasing adiponectin and decreasing leptin in AD patients. Nevertheless, no significant differences between patients and controls were found. AD women had significantly increased adipsin compared to controls, and there was a positive correlation of adipsin with age and disease duration. Although adipokines do not appear to be suitable biomarkers for early AD diagnosis, they certainly play a role in the pathogenesis of AD. Further studies will be needed to explain the cause of the adipokine “breaking point” that leads to the pathogenesis of overt AD., Markéta Vaňková, Gabriela Vacínová, Josef Včelák, Daniela Vejražková, Petra Lukášová, Robert Rusina, Iva Holmerová, Eva Jarolímová, Hana Vaňková, Běla Bendlová., and Obsahuje bibliografii
Výzkumná práce se zaměřuje na analýzu oblasti podpůrných opatření ve vzdělávání žáků se speciálními vzdělávacími potřebami. Hlavní oblastí studie je navyšování časové dotace na práci žáků se specifickými poruchami učení, což je jedna z nejčastěji volených forem podpory pro tyto žáky. Byla provedena kvantitativní analýza výkonu žáků 9. tříd základních škol. Výzkumný soubor obsahoval žáky se SPU (N=31) a intaktní žáky (N=188). Žáci pracovali na Testu struktury inteligence I-S-T 2000 R a jejich výkony byly následně statisticky zpracovány. Žáci se SPU měli k dispozici o 25 % na práci více, než žáci intaktní, ale byli hodnoceni také v základním čase. Pracovalo se s jejich výkonem v podobě hrubých skórů (tedy fakticky správně vyplněných položek), hrubé skóre se nepřevádělo na inteligenční kvocient. Statisticky významné výsledky byly zjištěny v následujících oblastech. Žáci se SPU podali v rámci své skupiny statisticky významně lepší výkon, pokud pracovali s navýšením času (než v čase základním), a to ve všech hodnocených škálách i subtestech. Při hodnocení rozdílu mezi žáky se SPU a intaktní skupinou žáků dosahovali žáci se SPU s přidaným časem navíc statisticky významně lepších výkonů ve figurální škále testu a v subtestu Výběr obrazců; statisticky významně horší výkon podali v numerickém subtestu Číselné řady. Pokud pracovali žáci se SPU a intaktní skupina žáků ve stejném (základním) čase, pak byli intaktní žáci statisticky významně úspěšnější v numerické škále. V rámci verbální škály nebyly zjištěny žádné statisticky významné rozdíly ve výkonech, což je překvapivým zjištěním. and The research focuses on the analysis of support measures in the education of pupils with special educational needs. The main area of the study is to increase the time allowance for the work of pupils with specific learning disabilities, which is one of the most frequently chosen forms of support for these pupils. The research is a quantitative analysis of the performance of 9 th -grade elementary school students. The research group included pupils with SPU (N = 31) and intact pupils (N = 188). The students worked on the I-S-T 2000 R Intelligence Structure Test and their performance was statistically processed. Pupils with SPU had 25% more time for work available than intact pupils, but they were also evaluated in basic time. We worked with their performance in the form of gross scores (that is correctly filled in items), the gross scores were not converted into intelligence quotients. Statistically significant results were found in the following areas. Pupils with SPU performed statistically significantly better within their group in all evaluated scales and subtests if they worked with increasing time (than in basic time). When we are evaluating the difference between pupils with SPU and an intact group of pupils, pupils with SPU with added extra time achieved statistically significantly better performances in the figural test scale and the Pattern Selection subtest. Statistically significantly worse performance was given in the numerical subtest of the Number Series. If students with SPU and an intact group of students worked at the same (base) time the intact students were statistically significantly more successful on the numerical scale. The surprising finding is that there are no statistically significant differences in performance within the verbal scale.
Respect for patientʼs autonomy is a key requirement of every ethical and legal codes. But what does it mean, autonomy? What concept of autonomy shall we choose? In modern bioethics, two concepts of autonomy dominate. The first is the so-called default theory created by Tom Beauchamp and James Childress, the second is the so-called split-level autonomy theory, sometimes referred to as the theory of authenticity. The first concept is derived from the concept of negative autonomy, the second is the idea of a positive interpretation of this word. The proven thesis of this article is that respect for that patient default autonomy is a necessary but not sufficient condition for an ethical relationship between the doctor and the patient. Respect for patient authenticity on the other hand cannot be a necessary condition for this ethical relationship, but it should be the ideal that a physician should seek to achieve, the moral of aspiration. Choosing one of these two concepts of autonomy has also key impact on the theory of informed consent, which will be proved as well. and Respekt k autonomii pacienta je klíčovým požadavkem plynoucí ze současných etických i právních kodexů. Není však zcela jisté, jaký koncept autonomie má být zvolen. Z toho plyne řada nejasností i pro teorii informovaného souhlasu. V současné moderní bioetice dominují dvě koncepce autonomie. První je tzv. defaultní teorie vytvořená Beauchampem a Childressem, druhá je tzv. teorie stupňovité autonomie, někdy nazývaná jako teorie autenticity. První koncepce je odvozena od koncepce tzv. negativní autonomie, druhá naopak předpokládá pozitivní výklad tohoto slova. Prokazovaná teze tohoto článku je ta, že respekt k tzv. defaultní autonomii pacienta je nutnou, nikoliv však postačující podmínkou pro etický vztah lékaře a pacienta. Respekt k stupňovité autonomii pacienta naopak nemůže být nutnou podmínkou pro etický vztah lékaře a pacienta, nicméně je klíčem pro dosažení tzv. morálky aspirace, ideálu, který by se měl lékař snažit dosáhnout. Výběr konceptu autonomie má pak zásadní dopady i na teorii informovaného souhlasu.