Növényi cirkadián óra-komponensek azonosítása és funkcionális jellemzése = Identification and functional characterization of components of the plant circadian clock

A cirkadián óra egy olyan genetikai alapokon nyugvó mechanizmus, amely képes kb. 24 órás periódushosszú oszcillációk létrehozására és ennek révén különböző életfolyamatok ritmikus szabályozására. Annak érdekében, hogy növényi óra újabb komponenseit fedezzük fel egy genetikai szűrés során cirkadián óra mutánsokat azonosítottunk Arabidopsisban. Genetikai térképezés majd az azt követő összehasonlító szekvenálás révén kimutattuk, hogy a mutánsok több, mint fele már ismert óragének új alléljeit reprezentálja. E mutánsok jellemzésével fontos új adatokhoz jutottunk több órafehérje funkcióját illetően. További 3 mutáció pozícióját mintegy 55-75 kbp kiterjedésű szakaszokra szűkítettük, amelyek szekvenálása folyamatban van. Mivel ezek a kromoszóma szakaszok nem tartalmaznak ismert óragént, a mutációk az óra új komponenseit érintik. A projekt legjelentősebb eredménye a lip1 (light insensitive period 1) mutáns azonosítása és jellemzése. Vad típusú növényekben az oszcillátor periódushossza függ a megvilágító fény intenzitásától: minél erősebb a fény, annál rövidebb a perióduszhossz. Kimutattuk, hogy a LIP1 fehérje alapvetően szükséges ehhez a szabályozáshoz, mivel hiányában a periódushossz minden fényviszony mellett azonos. Megállapítottuk, hogy a LIP1 gén egy funkcionális kis GTP-kötő fehérjét kódol, amely közvetett módon pozitívan szabályozza a GIGANTEA óragén transzkripcióját és feltehetően e kapcsolat révén hat az oszcillátor működésére. | Circadian clocks are genetic circuits capable of producing oscillations with ~ 24h period length and rhythmically regulating different biological processes. To learn more about the oscillatory mechanism of the plant circadian clock, we performed a genetic screen in Arabidopsis and identified several circadian mutants. Genetic mapping followed by comparative sequencing demonstrated that more than half of the mutants represent novel mutant alleles of known clock genes. Analysis of these new mutants provided valuable and novel data on the complex function of several clock proteins. Position of 3 additional mutations was delimited to 55-75 kbp regions, which are being sequenced. As these regions do not contain any known clock genes, the mutations must affect novel components of the clock. The most significant outcome of the project is the identification and characterisation of the lip1 (light insensitive period 1). In plants, there is an inverse relationship between the circadian period length and the intensity of the light: the period shortens with increasing light levels. LIP1 protein plays an essential role in this regulation, as the period length in lip1 is independent of light intensity. We isolated the LIP1 gene and demonstrated that it encodes a functional small GTP-binding protein. We showed that LIP1 positively regulates the transcription of the clock gene GIGANTEA that could be the mechanism by which LIP1 affects the function of the plant clock

Consumer perception of product recall in the food sector

The task of risk analysis is to estimate the risks associated with the hazards present in the food chain and to prevent or reduce potential harm with risk management and risk communication. Measures related to the restriction of the marketing of certain products are connected to the latter. In our article, related concepts are reviewed and the most important results of the representative consumer survey of the National Food Chain Safety Office (henceforward: NFCSO) on product recall are presented

Insects as "new" foods

The rapid growth of world population and the scarcity of natural resources are serious problems from an agricultural point of view, therefore, sustainable food production is an increasingly important issue. According to researchers, insects could mean the solution to the impending “protein crisis”, among other things. In recent years, society’s interest in the consumption of foods made of insects increased significantly in Europe, but it should be mentioned that entomophagy (the consumption of insects) is not a new phenomenon, because hints of it can already be found in the Bible. Several studies, discussing mainly the advantages and possible risks of insect consumption have already been prepared, however, our knowledge is still very limited. Although legislation is far from being uniform, we have to be prepared that, sooner or later, foods made of insects are likely to become part of our everyday diet

Online food shopping habits in Hungary

In recent years, the market segment of internet commerce has been developing intensively in Europe [6], although in Hungary, the growth rate had been lagging behind the European average for many years. A major part of the Hungarian population has only begun to show interest in the possibility of purchasing products and services online in the past five years, however, the trend is now clear in Hungary as well. While in 2012, only 35% of Hungarian internet users conducted online shopping transactions, by 2015 this ratio had increased to 47% [1]. The change in consumer habits is most clearly indicated by the fact that the percentage of regular internet users did not significantly change over the same period, it was 69% in 2012, and 72% in 2015 [3]. By comparing the two data sets it can be concluded that the increase in willingness to shop online showed a relative growth of exceptional proportions in Hungary, when compared to other EU member states. At the same time, according to the analysis of Eurostat, in 2015, food was put in the virtual shopping basket of Hungarians in only 10% of online purchases, which is far below the EU average (18%) [1]. When evaluating the results, we have to take into consideration that, in Hungary, only a very small number of webshops have foods in their portfolio, and online shops offering foods (as well) often cover only a small geographical area. Most certainly, the market share of online food purchases is expected to grow in the future, especially because of its convenient nature. According to the forecasts, the so-called consumer individualization will also grow at the same time, which could strengthen the segment of special foods (local, handcrafted and functional foods)

A brasszinoszteroidok szerepének vizsgálata a növényi szervek morfogenezisének szabályozásában = The regulatory role of brassinosteroids in the morphogenic determination of plant organs

A brasszinoszteroidok (BR-ok) növényi szteroid hormonok, amelyek fontos szerepet játszanak az egyedfejlődési és reproduktív funkciók szabályozásában. Munkánk célja olyan tényezők azonosítása volt, amelyek a sejtek szenzitizálása, ill. a hormon felhalmozása révén befolyásolhatják a BR válaszreakciókat. Kimutattuk, hogy a feltételezett egyenletes kifejeződéssel szemben a BR receptort kódoló BRI1 gén differenciált szerv- és fejlődés-specifikus expressziót mutat. BRI1 promóter-riporter fúziókat hordozó transzgenikus Arabidopsis vonalainkban a fokozott hormonérzékenység szoros korrelációt mutatott a receptor erős kifejeződésével, jelezve a receptor sűrűség és a válaszreakció kialakulása közti kapcsolatot. Másrészt meghatároztuk az aktív BR formák korábban ismeretlen szintjét az Arabidopsis egyes szerveiben, igazolva, hogy a hormon felhalmozódás mértékét jórészt a bioszintetikus gének transzkripciós szintű szabályozása határozza meg. A sebesség-meghatározó CPD/CYP90A1 enzimről episztázis analízissel kimutattuk, hogy az a szintézis hatékonyságát közvetlenül a BR szintézis első reakcióját követően kontrollálja. Az anyagcsereút utolsó, még tisztázatlan enzim funkcióját karakterizálva meghatároztuk, hogy a CPD/CYP90A1 a szteroid váz C-3 pozíciójának oxidációjáért felelős. Ezzel egyúttal kísérletes bizonyítékot szolgáltattunk egy új, a korábban ismertnél hatékonyabb BR szintézisút in vivo jelentőségére. | Brassinosteroids (BRs) are steroidal plant hormones controlling morphogenesis and reproductive development. The aim of our project was to elucidate basic mechanisms that influence BR responses by modulating cellular susceptibility or accumulation of the biologically active hormone. We demonstrated that, in contrast to an earlier concept of ubiquitous expression, the BRI1 gene encoding the BR receptor shows differential organ-specific and developmental activity. Our BRI1 promoter-reporter constructs revealed that in Arabidopsis elevated BRI1 expression coincides with increased BR responsiveness, suggesting an important role for receptor abundance in the initiation of BR signaling. In a different approach we determined the hitherto unknown distribution of active BRs in the various organs of Arabidopsis, and provided evidence that the transcriptional control of BR biosynthetic genes efficiently regulates hormone accumulation. We have shown that CPD/CYP90A1 is a key enzyme of BR biosynthesis and, using epistasis analysis, we demonstrated that it controls intermediate flow immediately downstream of the first committed step of the BR pathway. Characterizing the last unknown enzyme function in the BR pathway, we clarified by in vitro enzyme assays that CPD/CYP90A catalyzes the C-3 oxidation of early BR intermediates. Based on this result we proposed an enzymologically well supported novel BR biosynthetic pathway

Consumer perception of dual food quality based on a questionnaire survey

The dual quality of foods, i.e., the phenomenon that consumers find foods of different quality or composition in different countries under the same brand name and or with very similar packaging, has been one of the most pressing issues in the food chain in recent years. Predating the product comparative and consumer studies of the European Commission, the National Food Chain Safety Office has been investigating the issue since 2014 using several methodologies. In our article, the results of the consumer research carried out within the framework of the RCR-EFSQ CHAFEA project also supported by the EU. The issue of dual quality is given special attention in public perception. Nearly half of Hungarian consumers have noticed specific differences between foods of the same brand, available both in Western Europe and in Hungary. Three out of five respondents said that dual quality was not acceptable, and nine out of ten said that it was important for the manufacturer to inform the consumer about dual quality on the product label if there is such a phenomenon. Therefore, there is a clear need to address this issue at an official level, not only at a legal level as a result of the amendment of the directive, but also in terms of consumer information. Based on the opinion of the respondents, any differences should be clearly indicated on the packaging of the given product. The consumer opinions revealed in our research can provide guidance for the design of future product comparative studies, as well as for the consumer-friendly handling of the situation by manufacturers

Assessing the impact of the fipronil egg scandal on consumer behavior in Hungary

In addition to high pathogenicity avian influenza outbreak that started in the fall of 2016, the European poultry sector was also affected by the fipronil egg scandal that escalated quickly in August 2017. The above-mentioned incidents demanded rapid, decisive and coordinated action on the part of food chain safety authorities across Europe. Fast and continuous flow of credible information has been made possible by the Rapid Alert System for Food and Feed (RASFF) of the European Union. However, adequate authority measures alone do not guarantee the minimization of the economic damages caused by food scandals, therefore, great emphasis should be placed on risk communication as well in similar cases. The basic principles of risk communication include objectivity, timeliness and clarity [5]. This way, it is possible to avoid unreasonably high drops in consumption in cases where the real health risk is not significant, or the risk has already been eliminated by the action taken by the authorities or businesses. Changes in consumption habits were assessed by the National Food Chain Safety Office (NFCSO) in the fall of 2017 through a questionnaire survey based on personal interviews with 1,000 people. According to the results, thanks to the consistent communication activity of the authority, the confidence of Hungarian consumers in eggs and egg-containing products did not fundamentally drop, and this is of particular importance in the reduction of economic damages

A növényi cirkadián óra beállításának molekuláris mechanizmusa = The molecular mechanism of entrainment of the plant circadian clock

A növényi cirkadián óra magját, más eukariotákhoz hasonlóan, az ún. óragének alkotják, amelyek egymás működését szabályozva egy önfenntartó, mintegy 24 órás ritmust alakítanak ki saját kifejeződésük szintjén. Az óra számos alapvető életfolyamat napszakos megjelenését szabályozza, így fontos, hogy az óra működése összhangban legyen a valós idővel. A beállítás során jön létre ez az összhang. A legfontosabb beállító külső jel a fény, amelynek intenzitása hűen követi a napszakok váltakozását. Munkánk során azt vizsgáltuk, hogy a fény milyen molekuláris mechanizmusok útján állítja be az óra fázisát. Kimutattuk, hogy a fénypulzusok által kiváltott elsődleges változás bizonyos óragének transzkripciójának tranziens indukciója, amelyet passzív módon követ az adott fehérjék mennyiségének emelkedése, ami végül az óra fázis-csúszását eredményezi. Mutánsok vizsgálatával megállapítottuk, hogy egyes óragének indukciója pozitív, ill. negatív módon szabályozza az óra fényre adott válaszának erősségét. Megállapításunkat egy új indukciós rendszer felépítésével és alkalmazásával is igazoltuk, melynek segítségével egyedei óragének tranziens indukciójának hatását vizsgálhattuk. Elsőként bizonyítottuk, hogy az UV-B fény a látható fényhez hasonló mechanizmus útján állítja be az órát és igazoltuk, hogy az óra fázisfüggő módon gátolja egyes UV-B válaszok megjelenését. Azonosítottuk a fitokróm B fotoreceptor azon doménjét, amely a fényjeleket közvetett módon az órához (óragénekhez) továbbítja. | Circadian clocks are biochemical timing mechanisms providing temporal regulation to a wide range of molecular and physiological processes so that these processes are scheduled to the most appropriate time of the day/night cycle. In plants the central oscillator relies on transcriptional/translational feedback loops operated by the clock genes/proteins. The central oscillator is synchronized to the day/night cycle mainly by light signals (input), whereas the rhythmic signal from the oscillator is relayed via the output pathway. In this project, we have investigated the molecular mechanisms, by which light signals reset the clock. We showed that the primary effect of light signals is the transient transcriptional activation of certain clock genes, followed by concomitant increase in protein levels leading to phase shifts of the clock. Analysis of clock mutants led to the identification of clock genes, whose induction represent positive or negative effects on the magnitude of the phase response of the clock. This was verified by the use of a novel gene expression system allowing separate induction of single (clock)genes. We have demonstrated first that UV-B light resets the clock through the same mechanism as visible light does, and provided evidences that the clock inhibits certain UV-B responses in a phase-dependent manner. Moreover, we identified the particular domain of the phytochrome B photoreceptor that relays resetting signals towards the clock