Water balance modeling in the Eastern United States

The thesis adresses the water balance modeling issue by studying and comparing the performances of 5 water balance models at seasonal and annual time scale on 39 small/medium catchments spreaded throughout the eastern US. Two PET datasets are compared as well as the implication of inculuding the surface runoff by means of rainfall filtering. The final results is to obtain streamflow PDF in udgauged section by coupling WB models to a geomorphic model able estimate streamflow recessionsopenEmbargo per motivi di segretezza e/o di proprietà dei risultati e/o informazioni sensibil

Apeced in Turkey: a case report and insights on genetic and phenotypic variability

APECED is a rare monogenic recessive disorder caused by mutations in the AIRE gene. In this manuscript, we report a male Turkish patient with APECED syndrome who presented with chronic mucocutaneous candidiasis associated with other autoimmune manifestations developed over the years. The presence of the homozygous R257X mutation of the AIRE gene confirmed the diagnosis of APECED syndrome. We further performed literature review in 23 published Turkish APECED patients and noted that Finnish major mutation R257X is common in Turks. In particular, we assessed retrospectively how often the Ferre/Lionakis criteria would have resulted in earlier diagnosis in Finns, Sardinians and Turks in respect to the classic criteria. Since an earlier diagnosis could have been possible in 18.8% of Turkish, in 23.8% of Sardinian and 38.55% of Finnish patients we reviewed from literature, Ferre/Lionakis criteria could indeed allow in future earlier initiation of immunomodulatory treatments, if found effective in future studies

A novel homozygous mutation of the AIRE gene in an APECED patient from Pakistan: case report and review of the literature

Autoimmune-poly-endocrinopathy-candidiasis-ectodermal-dystrophy syndrome (APECED) is a rare monogenic recessive disorder caused by mutations in the autoimmune regulator (AIRE) gene. Criteria for the diagnosis of APECED are the presence of two of the following disorders: chronic mucocutaneous candidiasis (CMC), chronic hypoparathyroidism (CHP), and Addison's disease. APECED develops at high incidence in Finns, Sardinians, and Iranian Jews and presents with a wide range of clinical phenotypes and genotypes. In this manuscript, we report the clinical, endocrinological, and molecular features of a 16-year-old female patient from Pakistan living in Italy and presenting the major APECED clinical manifestations CMC, CHP, and primary adrenal insufficiency. Premature ovarian failure, chronic bronchopneumopathy, vitiligo, Hashimoto's thyroiditis emerged as associated diseases. In our patient, AIRE gene screening revealed the novel c.396G > C (p. Arg132Ser; p. R132S) mutation in homozygosity thus confirming APECED diagnosis. This is the first reported mutation within the nuclear localization signal (NLS) that is associated with APECED. The NLS mutation affects the nuclear import of classical transcription factors through nuclear pore by recognition of nuclear import receptors, the importin a molecules. By displaying crystal structures of the peptide containing the KRK basic residue cluster bound to a importins, we show that p. R132S replacement in 131-KRK-133 does not reproduce these interactions. Thus, we propose that the novel mutation exerts its pathogenetic effect by impairing the nuclear import of the Aire protein. The present case report is added to a limited series of Pakistani APECED patients who we reviewed from the scientific literature, mostly diagnosed on clinical findings

Cyanobacterial Production of Biopharmaceutical and Biotherapeutic Proteins

Efforts to express human therapeutic proteins in photosynthetic organisms have been described in the literature. Regarding microalgae, most of the research entailed a heterologous transformation of the chloroplast, but transformant cells failed to accumulate the desired recombinant proteins in high quantity. The present work provides methods and DNA construct formulations for over-expressing in photosynthetic cyanobacteria, at the protein level, human-origin bio-pharmaceutical and bio-therapeutic proteins. Proof-of-concept evidence is provided for the design and reduction to practice of "fusion constructs as protein overexpression vectors" for the generation of the bio-therapeutic protein interferon alpha-2 (IFN). IFN is a member of the Type I interferon cytokine family, well-known for its antiviral and anti-proliferative functions. Fusion construct formulations enabled accumulation of IFN up to 12% of total cellular protein in soluble form. In addition, the work reports on the isolation and purification of the fusion IFN protein and preliminary verification of its antiviral activity. Combining the expression and purification protocols developed here, it is possible to produce fairly large quantities of interferon in these photosynthetic microorganisms, generated from sunlight, CO2, and H2O

Dynamics of Photosystem II during short and long term response to light intensity: a biochemical and biophysical study

La fotosintesi è il processo attraverso il quale le piante assorbono l'energia solare per convertirla in energia chimica e, infine, in biomassa. Durante questo processo, varie funzioni chiave sono svolte dai fotosistemi, PSI e PSII, i quali sono straordinarie macchine per l'uso dell'energia solare, combinando l'alta efficienza quantica e la presenza di meccanismi inducibili al fine di evitare fotoinibizione. L'organizzazione peculiare dei fotosistemi è determinante per la loro funzione. Entrambi i fotosistemi sono costituiti da due porzioni: un complesso core e i complessi antenna (famiglia di proteine LHC). Le proteineLHC svolgono un ruolo fondamentale nella fotosintesi , essendo coinvolte nella raccolta della luce e nella fotoprotezione. Le proteine antenna del PSII, le subunità Lhcb, sono responsabili per il meccanismo di dissipazione termica di energia di eccitazione in eccesso (NPQ, quenching non-fotochimico). Chiarire i dettagli molecolari di induzione di NPQ nelle piante superiori è una grande sfida: nel mio lavoro di dottorato di ricerca, ho studiato in particolare la riorganizzazione dei domini proteici all'interno delle membrane tilacoidali dopo trattamento con un eccesso di luce, verificando la sua importanza per il pieno funzionamento durante NPQ.Photosynthesis is the process by which plants absorb solar energy and convert it to chemical energy and finally biomass. During this process, several key functions are carried out by Photosystems. PSI and PSII represent extraordinary machines for solar energy use, combining high quantum efficiency and the presence of inducible mechanisms in order to avoid photoinhibition which unavoidably derives from performing photosynthesis in oxygenic environment. The peculiar organization of Photosystems is determinant for function. Both Photosystems are composed by two moieties: a core complex and the antenna system (LHC protein family). LHC proteins play a key role in photosynthesis and are involved in both light harvesting and photoprotection. Among other photoprotecting mechanisms, antenna proteins of PSII, so-called Lhcb subunits, are responsible for the mechanism of thermal dissipation of excitation energy in excess (NPQ, non-photochemical quenching). Elucidating the molecular details of NPQ induction in higher plants has proven to be a major challenge. In my phD work, I investigated the reorganization of the protein domains inside grana membranes upon high light treatment and verified its importance for full functioning of NPQ. Below the main results obtained are summarized. Section A. Zeaxanthin modulates energy quenching properties of monomeric Lhcb antenna proteins. Among photosynthetic pigments, a special role is played by zeaxanthin (Zea), which is only accumulated under excess light. We studied the dynamics of xanthophylls binding to Lhcb proteins upon exposure of leaves to excess light. We found that Lhcb6 undergoes faster Zea accumulation than any other thylakoid protein so far described. We then studied in vitro modulation of Lhcb6 (CP24) functional properties by studying the effects of binding different xanthophyll species by using several spectroscopic techniques. The results suggest for Lhcb6 a special role in binding Zea and enhancing photoprotection under excess light. The Lhcb6 subunit is a recent addition to the photosynthetic apparatus of viridiplantae, being absent in algae and first appearing in mosses, together with the adaptation to the highly stressful conditions typical of land environment. Consistently, it is involved in several regulation mechanisms, as evidenced by genetic (de Bianchi, S. et al. 2008, Kovacs, L. et al. 2006) and biochemical analysis (Ballottari, M. et al. 2007). Previously it was reported to be involved in Non-Photochemical Quenching (NPQ) (Ahn, T. K. et al. 2008, Avenson, T. J. et al. 2008). In the second part of this section we focuses on fluorescence quenching and compared the effect of aggregation, which has been proposed to occur in vivo during NPQ due to a conformational change allowing energy transfer from Chl a excited states to the short lived carotenoid S1 excited state (Ruban, A. V. et al. 2007). This aggregation-dependent quenching (ADQ) has been proposed as an alternative to charge transfer quenching (CTQ) (Ahn, T. K. et al. 2008) mechanism proposed by other groups, including our laboratory. We studied the properties, particularly dependence on zeaxanthin binding, of ADQ using time-resolved and steady state spectroscopy. We obtained evidence that monomeric Lhcb proteins undergo ADQ even better than trimeric LHCII for which this mechanism was originally proposed. In these proteins the amplitude of the process is enhanced by zeaxanthin, while this is not the case for LHCII. Nevertheless, when LHCII is mixed with Lhcb6, this provides zeaxanthin-deppendent enhancement. This result complements previous studies of CTQ, which localized the quenching site to Chl 603, Chl 609, and Zea in carotenoid-binding site L2 (Ahn, T. K. et al. 2008) and suggests that two different types of quenching may occur in Lhcb proteins. Section B. Membrane dynamics during NPQ: PsbS and zeaxanthin-dependent reorganization of Photosystem II is controlled by dissociation of a pentameric supercomplex. Antenna subunits heve been shown to host the site of energy quenching, while the trigger of the mechanism is mediated by PsbS (Bonente, G. et al. 2008), a PSII subunit involved in transducing the signal of over-excitation consisting into lumen acidification (Li, X. P. et al. 2002, Li, X. P. et al. 2004). In this section we investigate the molecular mechanism by which PsbS regulates light harvesting efficiency. We showed that PsbS controls the association/dissociation of a five-subunit membrane complex, composed of two monomeric Lhcb proteins, Lhcb4 and Lhcb6 and the trimeric LHCII-M (namely Band 4 Complex - B4C). We demonstrated that the dissociation of this supercomplex is indispensable for the onset of non-photochemical fluorescence quenching in high light. Direct observation of grana membranes upon treatment with excess light for different timelengths by electron microscopy and image analysis showed that B4C dissociation leads to the redistribution of PSII within grana membranes, reducing average distances between PSII core complexes. This phenomenon was reversible upon dark relaxation. We interpret these results proposing that the dissociation of B4C makes quenching sites, possibly Lhcb4 and Lhcb6, available for the switch to an energy-quenching conformation. Section C. New insights on the role of the monomeric Lhcb4 antenna subunit. PSII is surrounded by a external antenna system composed by trimeric LHCII and monomeric minor antenna complexes. Several evidences suggests that Lhcb4, in particular, is a key factor in both light harvesting and photoprotection (Ballottari, M. et al. 2007) or under chronic excitation of PSII (Morosinotto, T. et al. 2006), b) is able to perform charge transfer quenching (Ahn, T. K. et al. 2008). We characterized the function of Lhcb4 subunits in Arabidopsis thaliana. In order to determine the function of Lhcb4 in A. thaliana, we have constructed knock-out mutants lacking one or more Lhcb4 isoforms and analyzed their performance in photosynthesis and photoprotection. The absence of Lhcb4 also caused a destabilization of PSII supercomplexes, modifying antenna system organization. The distribution of PSII complexes within grana membranes is affected in koLhcb4 and LHCII enriched domains are formed. PSII quantum efficiency and NPQ activity were affected, and photoprotection efficiency under high light conditions was impaired in koLhcb4 plants with respect to either WT or mutants depleted of any other Lhcb subunit. Electron microscopy analysis reveal that PSII supercomplex from koLhcb4 plants bears a hole in its structure. We conclude that Lhcb4 is a fundamental component of PSII which is essential for maintenance of both the function and structural organization of this photosystem. Section D. Chlorophyll b reductase affected the regulation of antenna complexes during light stress. The molecular mechanism of antenna complexes breakdown is largely unknown and it is still unclear whether chlorophyll degradation precedes the degradation of the protein moiety or whether protein degradation is the first event. Recently chlorophyll b reductase mutant has been isolated (Kusaba, M. et al. 2007). This enzyme is responsible for the first step of chlorophyll degradation pathway, the conversion of Chlorophyll (Chl) b in Chl a and the mutant is called “stay-green”, because of PSII antenna retention upon leaf senescence induction (Horie, Y. et al. 2009). We characterized the response of Chl b reductase ko mutant to acclimation in high light. The mutant showed a slower antenna size reduction with respect to WT. This enzyme is upregulated during HL acclimation. In vitro assay with recombinant Chl b reductase demonstrated that its activity is higher when zeaxanthin, which accumulate during stress, is bound to PSII antenna complexes

Is the Hyporheic Zone Relevant beyond the Scientific Community?

Rivers are important ecosystems under continuous anthropogenic stresses. The hyporheic zone is a ubiquitous, reactive interface between the main channel and its surrounding sediments along the river network. We elaborate on the main physical, biological, and biogeochemical drivers and processes within the hyporheic zone that have been studied by multiple scientific disciplines for almost half a century. These previous efforts have shown that the hyporheic zone is a modulator for most metabolic stream processes and serves as a refuge and habitat for a diverse range of aquatic organisms. It also exerts a major control on river water quality by increasing the contact time with reactive environments, which in turn results in retention and transformation of nutrients, trace organic compounds, fine suspended particles, and microplastics, among others. The paper showcases the critical importance of hyporheic zones, both from a scientific and an applied perspective, and their role in ecosystem services to answer the question of the manuscript title. It identifies major research gaps in our understanding of hyporheic processes. In conclusion, we highlight the potential of hyporheic restoration to efficiently manage and reactivate ecosystem functions and services in river corridors. View Full-Tex

Predicting streamflow distributions and flow duration curves from landscape and climate

Characterizing the probability distribution of streamflows in catchments lacking in discharge measurements represents an attractive prospect with consequences for practical and scientific applications, in particular water resources management. In this paper, a physically-based analytic model of streamflow dynamics is combined with a set of water balance models and a geomorphological recession flow model in order to estimate streamflow probability distributions based on catchment-scale climatic and morphologic features. The models used are described and the novel parameterization approach is elaborated on. Starting from rainfall data, potential evapotranspiration and digital terrain maps, the method proved capable of capturing the statistics of observed streamflows reasonably well in 11 test catchments distributed throughout the United States, east of the rocky mountains. The method developed offers a unique approach for estimating probability distribution of streamflows where only climatic and geomorphologic features are known

The Effect of Stream Discharge on Hyporheic Exchange

Streambedmorphology, streamflow dynamics, and the heterogeneity of streambed sediments critically controls the interaction between surfacewater andgroundwater. The present study investigated the impact of different flowregimes on hyporheic exchange in a boreal streamin northern Sweden using experimental and numerical approaches. Low-, base-, and high-flow discharges were simulated by regulating the streamflow upstreamin the study area, and temperature was used as the natural tracer to monitor the impact of the different flow discharges on hyporheic exchange fluxes in stretches of stream featuring gaining and losing conditions. A numerical model was developed using geomorphological and hydrological properties of the stream and was then used to perform a detailed analysis of the subsurface water flow. Additionally, the impact of heterogeneity in sediment permeability on hyporheic exchange fluxes was investigated. Both the experimental and modelling results show that temporally increasing flowresulted in a larger (deeper) extent of the hyporheic zone aswell as longer hyporheic flow residence times. However, the result of the numerical analysis is strongly controlled by heterogeneity in sediment permeability. In particular, for homogeneous sediments, the fragmentation of upwelling length substantially varies with streamflow dynamics due to the contribution of deeper fluxes