Spindle Positioning, Meiotic Nonreduction, and Polyploidy in Plants

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The Chromatin Protein DUET/MMD1 Controls Expression of the Meiotic Gene TDM1 during Male Meiosis in Arabidopsis.

Meiosis produces haploid cells essential for sexual reproduction. In yeast, entry into meiosis activates transcription factors which trigger a transcriptional cascade that results in sequential co-expression of early, middle and late meiotic genes. However, these factors are not conserved, and the factors and regulatory mechanisms that ensure proper meiotic gene expression in multicellular eukaryotes are poorly understood. Here, we report that DUET/MMD1, a PHD finger protein essential for Arabidopsis male meiosis, functions as a transcriptional regulator in plant meiosis. We find that DUET-PHD binds H3K4me2 in vitro, and show that this interaction is critical for function during meiosis. We also show that DUET is required for proper microtubule organization during meiosis II, independently of its function in meiosis I. Remarkably, DUET protein shows stage-specific expression, confined to diplotene. We identify two genes TDM1 and JAS with critical functions in cell cycle transitions and spindle organization in male meiosis, as DUET targets, with TDM1 being a direct target. Thus, DUET is required to regulate microtubule organization and cell cycle transitions during male meiosis, and functions as a direct transcription activator of the meiotic gene TDM1. Expression profiling showed reduced expression of a subset comprising about 12% of a known set of meiosis preferred genes in the duet mutant. Our results reveal the action of DUET as a transcriptional regulator during male meiosis in plants, and suggest that transcription of meiotic genes is under stagewise control in plants as in yeast

Varroa destructor exacerbates the negative effect of cold contributing to honey bee mortality

Several concurrent stress factors can impact honey bee health and colony stability. Although a satisfactory knowledge of the effect of almost every single factor is now available, a mechanistic understanding of the many possible interactions between stressors is still largely lacking. Here we studied, both at the individual and colony level, how honey bees are affected by concurrent exposure to cold and parasitic infection. We found that the parasitic mite Varroa destructor, further than increasing the natural mortality of bees, can induce an anorexia that reduces their capacity to thermoregulate and thus react to sub-optimal temperatures. This, in turn, could affect the collective response of the bee colony to cold temperatures aggravating the effect already observed at the individual level. These results highlight the important role that biotic factors can have by shaping the response to abiotic factors and the strategic need to consider the potential interactions between stressors at all levels of the biological organization to better understand their impact

Chromatin dynamics during interphase and cell division:similarities and differences between model and crop plants

Genetic information in the cell nucleus controls organismal development, responses to the environment and finally ensures own transmission to the next generations. To achieve so many different tasks, the genetic information is associated with structural and regulatory proteins, which orchestrate nuclear functions in time and space. Furthermore, plant life strategies require chromatin plasticity to allow a rapid adaptation to abiotic and biotic stresses. Here, we summarize current knowledge on the organisation of plant chromatin and dynamics of chromosomes during interphase and mitotic and meiotic cell divisions for model and crop plants differing as to the genome size, ploidy and amount of genomic resources available. The existing data indicate that chromatin changes accompany most (if not all) cellular processes and that there are both shared and unique themes in the chromatin structure and global chromosome dynamics among species. Ongoing efforts to understand the molecular mechanisms involved in chromatin organisation and remodeling have, together with the latest genome editing tools, potential to unlock crop genomes for innovative breeding strategies and improvements of various traits

Progettazione e implementazione di un sistema per la gestione dell'energia in ambito domestico, con interfaccia utente Android

LAUREA SPECIALISTICAI consumi elettrici in contesti residenziali sono in continua crescita a livello mondiale, a causa dell'aumento del numero di elettrodomestici presenti, ma anche per via di un loro impiego non sempre efficiente. Una possibile soluzione a tal problema è rappresentata dalla Smart Grid, una rete di comunicazione a supporto della rete elettrica in grado di fornire le informazioni necessarie a una gestione più accorta dell'energia. Per rendere l'utenza domestica parte attiva delle Smart Grid, occorre instaurare una interazione flessibile tra queste due entità, basata sulla ottimizzazione delle attività da svolgere e sullo sfruttamento di eventuale produzione elettrica locale. Questo lavoro di tesi si focalizza sulla gestione dell'uso degli elettrodomestici, proponendo, in particolare, un sistema in grado di controllare efficientemente i consumi elettrici di gruppi di case al fine di ottenere benefici sia per l'utente che per la rete stessa. Programmando intelligentemente l'utilizzo dei dispositivi elettrici, infatti, è possibile trarre guadagno sfruttando le tariffe orarie, e al contempo evitare picchi nella richiesta aggregata di energia elettrica. Il sistema proposto integra al suo interno una rete di sensori con lo scopo di monitorare il consumo di energia delle abitazioni. Inoltre, tramite l'impiego di un algoritmo di ottimizzazione, lo stesso fornisce programmi di esecuzione giornalieri degli elettrodomestici al gruppo di case a cui è connesso. L'interazione con l'utente avviene mediante una applicazione per dispositivi mobili che permette di ricavare le informazioni calcolate dal sistema, nonché altri dati utili quali il consumo istantaneo e statistiche.Power consumption by household users continues to rise throughout the world, as a result of both the growing number of appliances and the operation of such appliances, which is not always efficient. A possible solution to this problem is the Smart Grid, a communications network supporting the electrical grid and capable of providing the information required for a smarter use of power. In order to allow household users to become active parts in Smart Grids, a flexible interaction between these two entities must be ensured. This interaction should be based on the optimization of the tasks to be carried out, and on the exploitation of local power generation, if any. This work focuses on the management of appliance operation. In particular, it proposes a system which can efficiently control the power consumption of clusters of households, so as to ensure benefits to both users and the grid itself. Smart scheduling of the operation of electrical equipment allows users to benefit from cheaper off-peak power rates, while also helping to prevent peaks in the aggregate demand of power. The proposed system integrates a network of sensors designed to monitor power consumption in households. Through the use of an optimization algorithm, it also provides daily appliance operation schedules to the cluster of homes it is connected to. The interaction with the user takes place by means of an application designed for mobile devices. This application provides the user with the information calculated by the system, as well as other useful data, such as the instantaneous power consumption and relevant statistics