ΧΡΗΣΗ ΜΗΝΙΑΙΩΝ ΔΕΔΟΜΕΝΩΝ ΓΙΑ ΤΗΝ ΕΚΤΙΜΗΣΗ ΤΗΣ ΕΞΑΤΜΙΣΟΔΙΑΠΝΟΗΣ ΑΝΑΦΟΡΑΣ ΜΕ ΒΑΣΗ ΤΗ ΘΕΡΜΟΚΡΑΣΙΑ ΣΕ ΔΑΣΟΣ

Σκοπός της εργασίας είναι η διερεύνηση της ακρίβειας εκτίμησης της εξατμισοδιαπνοής αναφοράς (ΕΤο) των μεθόδων Hargreaves (HAR), Hargreaves-Samani (H-S) και τεσσάρων τροποποιήσεών της (HS1, HS2, HS3, HS4) με μηνιαία δεδομένα εισόδου 23 ετών (1996-2018), σε σχέση με την FAO56 Penman-Monteith (PM) σε δασικό περιβάλλον. Τα αποτελέσματα υποδεικνύουν ότι όλες οι μέθοδοι και κυρίως οι HAR, HS2 και H-S, εμφανίζουν ικανοποιητική ακρίβεια και συστήνεται η χρήση τους για την εκτίμηση της μηνιαίας ΕΤο σε δασικό μεσογειακό περιβάλλον. Παρόλα αυτά η εποχικότητα, το χρονικό βήμα και η ύπαρξη ξηρών ή υγρών ετών επηρεάζει την αποτελεσματικότητα των μεθόδων και πρέπει να λαμβάνονται υπόψη κατά την υιοθέτηση της κατάλληλης μεθόδου

Applicability of an empirical runoff estimation method in central Greece

In order to assess the water runoff on the sloping cultivated fields of Central Greece, an experiment was carried out from 1997 to 2000. The following treatments were used: three tillage methods, viz. conventional tillage, reduced tillage with heavy cultivator and disk-harrow: two with or without winter cover crop, two parallel and perpendicular to the contour tillage and planting directions. An existing methodology for predicting runoff was evaluated and improved, which is based on the estimation of pending time for the different tillage systems in the study area under rainfall. An equation predicting the time to ponding was used obtaining data from infiltration experiments using double-cylinder infiltrometers in the field. The surface runoff of each rain storm was estimated by combining the appropriate infiltration equation with the rain intensity data, taking into consideration not only the excess rainfall rate over the infiltration rate, but also the surface detention. Measured runoff was used to test the validity of the USDA-Soil Conservation Service (SCS) curve number method in the region. The results from this test indicated that this prediction runoff method may not be used in the region without the proper modifications to suit the rainfall in the region. The developed model could be used to successfully estimate runoff and erosion in the area. It was found that the combination of equations of time to incipient ponding and the maximum surface storage capacity of topsoil, could explain about 85% of the existing runoff variation. (c) 2006 Elsevier B.V. All rights reserved

Isolation, characterization, and sequencing of nodavirus in sturgeon (Acipenser gueldestaedi L.) reared in freshwater facilities

The study demonstrates the presence of a nodavirus that affected sturgeon in fresh water, causing disease with neurological signs. The virus was isolated and inoculated onto SSN-1 (striped snakehead, Channa striatus) cell cultures where cytopathic effects (CPE) of the virus included vacuolation of the cells and degeneration of the monolayer. A 255 bp amplicon from nucleic acid preparations of brain tissue from infected sturgeon was detected by PCR (RT-PCR and nested-PCR) and compared with corresponding amino acid sequences of other infected species. The sequences from the sturgeon were similar to those of sea bass, red spotted grouper, and European eel, supporting the hypothesis that the virus originated in marine fish and was horizontally transmitted to freshwater sturgeon

Cloning and functional characterization of the ovine Hormone Sensitive Lipase (HSL) full-length cDNAs: An integrated approach

Hormone Sensitive Lipase (HSL) is a highly regulated enzyme that mediates lipolysis in adipocytes. HSL enzymatic activity is increased by adrenergic agonists, such as catecholamines and glucagons, which induce cyclic AMP (cAMP) intracellular production, subsequently followed by the activation of Protein Kinase A (PKA) and its downstream signalling cascade reactions. Since HSL constitutes the key enzyme in the regulation of lipid stores and the only enzyme being subjected to hormonal regulation [in terms of the recently identified Adipose Triglyceride Lipase (ATGL)], the ovine Hormone Sensitive Lipase (ovHSL) full-length cDNA clones were isolated, using a Polymerase Chain Reaction-based (PCR) strategy. The two isolated isoforms ovHSL-A and ovHSL-B contain two highly homologous Open Reading Frame (ORF) regions of 2.089 Kb and 2.086 Kb, respectively, the latter having been missed the 688th triplet coding for glutamine (ΔQ688). The putative 695 and 694 amino acid respective sequences bear strong homologies with other HSL protein family members. Southern blotting analysis revealed that HSL is represented as a single copy gene in the ovine genome, while Reverse Transcription-PCR (RT-PCR) approaches unambiguously dictated its variable transcriptional expression profile in the different tissues examined. Interestingly, as undoubtedly corroborated by both RT-PCR and Western blotting analysis, ovHSL gene expression is notably enhanced in the adipose tissue during the fasting period, when lipolysis is highly increased in ruminant species. Based on the crystal structure of an Archaeoglobus fulgidus enzyme, a three-dimensional (3D) molecular model of the ovHSL putative catalytic domain was constructed, thus providing an inchoative insight into understanding the enzymatic activity and functional regulation mechanisms of the ruminant HSL gene product(s). © 2008 Elsevier B.V. All rights reserved

Cloning and functional characterization of the 5′ regulatory region of ovine Hormone Sensitive Lipase (HSL) gene

Hormone Sensitive Lipase (HSL) catalyzes the rate-limiting step in the mobilization of fatty acids from adipose tissue, thus determining the supply of energy substrates in the body. HSL enzymatic activity is increased by adrenergic agonists, such as catecholamines and glucagons, which induce cyclic AMP (cAMP) intracellular production, subsequently followed by the activation of Protein Kinase A (PKA) and its downstream signaling cascade reactions. HSL constitutes the critical enzyme in the modulation of lipid stores and the only component being subjected to hormonal control in terms of the recently identified Adipose Triglyceride Lipase (ATGL). In order to acquire detailed knowledge with regard to the mechanisms regulating ovine HSL (ovHSL) gene transcription activity, we initially isolated and cloned the 5′ proximal and distal promoter regions through a genome walking approach, with the utilization of the already characterized ovHSL cDNAs. As evinced by BLAST analysis and a multiple alignment procedure, the isolated genomic fragment of 2.744 kb appeared to contain the already specified 5′-untranslated region (5′-UTR), which was interrupted by a relatively large intron of 1.448 kb. Regarding the upstream remaining part of 1.224 kb, it was demonstrated to represent a TATA-less promoter area, harboring several cis-regulatory elements that could be putatively recognized by relatively more general transcription factors, mainly including Stimulating protein 1 (Sp1), CCAAT-box Binding Factors (CBFs), Activator Protein 2 (AP2) and Glucocorticoid Receptor (GR), as well as other cis-acting regions denominated as Insulin Response Element (IRE), Glucose Response Element (GRE), Fat Specific Element (FSE) and cAMP Response Element (CRE), which could likely function in a nourishment (i.e. glucose)-/hormone-dependent fashion. When different genomic fragments were directionally (5′ to 3′) cloned into a suitable reporter vector upstream of a promoter-less luciferase gene and transiently transfected into 3T3-L1 (mouse fibroblasts) as well as T24 (human bladder cancer) cell lines, strong promoter activities were unambiguously detected, with the - 140/+ 18 nucleotide sequence bearing the highest transcriptional response, thus indicating that the 1.224 kb 5′ flanking region, isolated by genome walking, veritably contains the ovHSL gene promoter. Of particular significance are the observations that the functional promoter fragments could trigger the transcriptional activity of luciferase gene only under high concentration of glucose conditions in both cell lines. © 2008 Elsevier B.V. All rights reserved