28 research outputs found
LeProT1, a Transporter for Proline, Glycine Betaine, and γ-Amino Butyric Acid in Tomato Pollen
No full textDuring maturation, pollen undergoes a period of dehydration accompanied by the accumulation of compatible solutes.Solute import across the pollen plasma membrane, which occurs via proteinaceous transporters, is required to support pollen development and also for subsequent germination and pollen tube growth. Analysis of the free amino acid composition of various tissues in tomato revealed that the proline content in flowers was 60 times higher than in any other organ analyzed. Within the floral organs, proline was confined predominantly to pollen, where it represented >70 of total free amino acids. Uptake experiments demonstrated that mature as well as germinated pollen rapidly take up proline. To identify proline transporters in tomato pollen, we isolated genes homologous to Arabidopsis proline transporters. LeProT1 was specifically expressed both in mature and germinating pollen, as demonstrated by RNA in situ hybridization. Expression in a yeast mutant demonstrated that LeProT1 transports proline and γ-amino butyric acid with low affinity and glycine betaine with high affinity. Direct uptake and competition studies demonstrate that LeProT1 constitutes a general transporter for compatible solutes
FAD is a further essential cofactor of the NAD(P)H and O2-dependent zeaxanthin-epoxidase
No full textAbstractIn chloroplasts of plants the xanthophyll cycle is suggested to function as a protection mechanism against photodamage. Two enzymes catalyze this cycle. One of them, violaxanthin de-epoxidase, transforms violaxanthin (Vio) to zeaxanthin (Zea) via antheraxanthin (Anth) and is bound to the lumenal surface of the thylakoid vesicles, when being in its active state. The other enzyme, Zea-epoxidase, is responsible for the backward reaction (Zea → Anth → Vio) and is active at the stromal side of the thylakoid. For the epoxidation of Zea this enzyme requires NAD(P)H and O2 as cosubstrates. Using isolated thylakoid membranes we found that FAD enhances the epoxidase activity (decrease of apparent Km for NAD(P)H and two-fold increase of Vmax). The flavin functions as a third cofactor which is partially lost during the isolation procedure of thylakoids. Other flavins, such as FMN or riboflavin are without effect. The involvement of FAD in the enzymatic reaction is also demonstrated by the inhibitory action of diphenyleneiodoniumchloride (DPI) (IC50 = 2.3 μM), a compound that blocks the reoxidation of reduced flavins within enzymes. The Zea-epoxidase is a multicomponent enzyme system which can be classified as FAD-containing, NAD(P)H- and O2-dependent monooxygenase that is able to epoxidize 3-hydroxy β-ionone rings of xanthophylls in the 5,6 position
The role of Δ<sup>1</sup>-pyrroline-5-carboxylate dehydrogenase in proline degradation
No full textIn response to stress, plants accumulate Pro, requiring degradation after release from adverse conditions. Delta1-Pyrroline-5-carboxylate dehydrogenase (P5CDH), the second enzyme for Pro degradation, is encoded by a single gene expressed ubiquitously. To study the physiological function of P5CDH, T-DNA insertion mutants in AtP5CDH were isolated and characterized. Although Pro degradation was undetectable in p5cdh mutants, neither increased Pro levels nor an altered growth phenotype were observed under normal conditions. Thus AtP5CDH is essential for Pro degradation but not required for vegetative plant growth. External Pro application caused programmed cell death, with callose deposition, reactive oxygen species production, and DNA laddering, involving a salicylic acid signal transduction pathway. p5cdh mutants were hypersensitive toward Pro and other molecules producing P5C, such as Arg and Orn. Pro levels were the same in the wild type and mutants, but P5C was detectable only in p5cdh mutants, indicating that P5C accumulation may be the cause for Pro hypersensitivity. Accordingly, overexpression of AtP5CDH resulted in decreased sensitivity to externally supplied Pro. Thus, Pro and P5C/Glu semialdehyde may serve as a link between stress responses and cell death
Uncoupling of Photophosphorylation by Triethyl Lead (Et3Pb+) Generated from Tetraethyl Lead (Et4Pb) in Illuminated Chloroplasts
No full textA legal approach to whether ai generated content should be protected under copyright
No full textSubmitted in partial fulfilment of the requirements for the degree of Master of Laws by Coursework and Research Report at the University of the Witwatersrand, JohannesburgCurrently, there is no clear answer for whether AI-generated content should be protected under copyright law in South Africa and if so, who is the author and who owns the copyright. As AI is growing more advanced and widely used, the potential for confusion grows and thus clarity on the law’s position is important. In this paper, I will examine how AI generates works and compare this to the purpose of copyright law. I will then determine whether granting AI- generated works copyright protection aligns with the purpose of copyright law. Further, I will conduct an analysis on how different countries have dealt with the question of whether AI-generated content should be protected under copyright. This will help pinpoint the factors to consider when answering this question such as the requirement of human authorship, legal or juristic person ownership of the copyright and whether the works are copyrightable. It is important to consider how South Africa’s legal system should approach issues surrounding AI-generated content and copyright. In examining the South African legal position on this question, I will conduct an analysis on the approaches taken by the US, the UK, Germany, Australia, China, and South Africa in relation to AI-generated works and copyright. This range of countries will allow for a greater understanding of the issues, complexities, and factors to consider while answering this questionMM202
Metabolic profiling and population screening of analgesic usage in nuclear magnetic resonance spectroscopy-based large-scale epidemiologic studies
No full textThe application of a 1H nuclear magnetic resonance (NMR) spectroscopy-based screening method for determining the use of two widely available analgesics (acetaminophen and ibuprofen) in epidemiologic studies has been investigated. We used samples and data from the cross-sectional INTERMAP Study involving participants from Japan (n = 1145), China (n = 839), U.K. (n = 501), and the U.S. (n = 2195). An orthogonal projection to latent structures discriminant analysis (OPLS-DA) algorithm with an incorporated Monte Carlo resampling function was applied to the NMR data set to determine which spectra contained analgesic metabolites. OPLS-DA preprocessing parameters (normalization, bin width, scaling, and input parameters) were assessed systematically to identify an optimal acetaminophen prediction model. Subsets of INTERMAP spectra were examined to verify and validate the presence/absence of acetaminophen/ibuprofen based on known chemical shift and coupling patterns. The optimized and validated acetaminophen model correctly predicted 98.2%, and the ibuprofen model correctly predicted 99.0% of the urine specimens containing these drug metabolites. The acetaminophen and ibuprofen models were subsequently used to predict the presence/absence of these drug metabolites for the remaining INTERMAP specimens. The acetaminophen model identified 415 out of 8436 spectra as containing acetaminophen metabolite signals while the ibuprofen model identified 245 out of 8604 spectra as containing ibuprofen metabolite signals from the global data set after excluding samples used to construct the prediction models. The NMR-based metabolic screening strategy provides a new objective approach for evaluation of self-reported medication data and is extendable to other aspects of population xenometabolome profiling
Quality assurance framework – the concept of quality assurance applied to fisheries data and its operationalisation under the ICES scope.
No full textMuseology: an academic discipline or form of cultural activity?
No full textMuseology is the science of museums. Most experts characterize it as an independent applied scientific discipline, which studies how museums develop and optimize their activities to meet the needs of society. The term "museology" was first mentioned in the work by P.L. Martin "Praxix der Naturgeschichte" published in 1869 in Germany. But the determination of the status of museology as a science was first given by J. G. Th. Von Graesse in the article "Museology as a Science" published in the magazine „Zeitschrift für Museologie und Antiquitätenkunde" in 1883. The author announced a new scientific discipline of museology and tried to highlight its research potential. Thus, museology as a science began in 1883.
Since 1960s museology is introduced as a scientific discipline in many universities around the world; there were created first centers of museological research, published numerous papers on museums. However, so far, some experts deny the scientific character of museology considering it "a discipline that coordinates a specialized type of cultural activity".
In his article, the author analyzes the path of museology in the process of its development as a scientific discipline, identifies the problems of its classification in the system of sciences, and highlights the contributions of some researchers (P. van Mensch, J. Neustupny, T. Šola, Z. Stransky, R. Florescu, etc.) to the consolidation of its status of an independent science. In conclusion, the author believes that museology is an academic science, but a relatively young and developing
Musealization in the system of senses of cultural memory
No full textВ статті розглядаються проблеми, що пов’язані з вивченням природи
музею та його місце у соціально-культурному просторі. Автор
звертається до розвідкам відносно цього питання одного з засновникам
сучасної музеології З. З. Странського. Концепти, що запровадив
Странський для вивчення природи музею як культурного інституту,
попри їх дискусійність, є дієвим інструментом для осмислення музейності
як характеристики окремого людського існування. Для вирішення цього
питання Странський пропонує декілька нових наукових понять –
«культурна метадійсность». «музеалізація», «музеальне освоєння
дійсності», «музеаліта». Можна стверджувати, що кожна людина
потенційно може виступити як «музей». Деякі предмети, що оточують
людину, можуть втрачати своє побутове значення, трансформуючись
на «музеаліти», набуваючи нові цінність та статус.The article is divided to the problems related to the studying the phenomenon
of the museum and its place in the socio-cultural space. The museum is one of
the fundamental socio-cultural institutions that designed to present, preserve
and distribute cultural, historical and artistic values. There are the museums
that should determine what is a cultural value that is a worthy representation
of national and universal cultural codes. The development of museums
demonstrates their ability to transform reality in a special way, namely, to
endow reality with specific properties in relation to the cultural-memorial
value of their authentic representatives. Modern museology defines such a
process as museumization, which transforms reality into “cultural metareality”.
The author refers to the researching museological conception of Z.
Z. Stransky, one of the founders of modern museology. The concepts introduced
by Stransky to studying the museum as a cultural institution, despite their
debatable in special literature, are an effective tool for understanding
museumness as a characteristic of individual human existence. To solve this
problem, Stranskyi proposes several new scientific concepts – “cultural metareality”.
“musealization”, “museum development of reality”, “musealite”. It
can be argued that every person can potentially act as a “museum”. Some
objects surrounding a person can lose their everyday meaning, transforming
into “museum objects” and they are acquiring new value and status. Nowadays the museum is transformed from exclusively a repository of memory into a
special space aimed to determining orientations to Future
