The Effects of Νatural Enemies on Aphid Populations on Processing Tomato in Central Greece

Στα πλαίσια της εργασίας αυτής μελετήθηκαν η σύνθεση και το ύψος των πληθυσμών των αφίδων και των φυσικών τους εχθρών σε καλλιέργεια βιομηχανικής τομάτας στην περιοχή Βάγια Βοιωτίας. Για το σκοπό αυτό λαμβάνονταν δείγματα νέων και ώριμων φύλλων από φυτεία βιομηχανικήςτομάτας ποικιλίας Η 30 κατά τις καλλιεργητικές περιόδους των ετών 1992 και 1993. Τα αποτελέσματα έδειξαν ότι γενικά οι αριθμοί των αφίδοιν και των φυσικών εχθρών τους ήταν υψηλότεροι στα νέα από ότι στα ο')ριμα φύλλα. Τα είδη αφίδων που ανέπτυξαν πληθυσμούς επί των φυτών ήταν τα Macrosiphum euphorbiae (Thomas) και Myzus persicae (Sulzer). Οι πληθυσμοί του M.euphorbiae ήταν πολΰ υψηλότεροι από αυτούς του M. persicae και κατά τα δύο έτη της μελέτης, παρουσιάζοντας μέγιστο κατά τη διάρκεια του Αυγούστου. Οι φυσικοί εχθροί που βρέθηκαν ήταν τα αρπακτικά Macrolophus pygmaeus Rambur (Hemiptera: Miridae) και Orius niger Wolff (Hemiptera: Anthocoridae). καθώς και είδη των οικογενειών Syrphidae και Chrysopidae. Επίσης, σημειώθηκαντα παρασιτοειδή Aphelinus abdominalis Dalman (Hymenoptera: Aphelinidae) καιPraon volucre (Haliday) (Hymenoptera: Aphidiidae). Ακμαία και νύμφες του αρπακτικού Μ. pygmaeus βρέθηκαν σε υψηλούς πληθυσμούς κυρίως κατά τη διάρκεια του Αυγούστου και του Σεπτεμβρίου, η δε ανάπτυξη του πληθυσμού του ακολούθησε αυτή το>ν αφίδων γεγονός που υποδηλώνει την αριθμητική αντίδραση του αρπακτικού στην αύξηση της πληθυσμιακής πυκνότητας τηςλείας του. Το Ο. niger βρέθηκε σε πολύ μικρούς πληθυσμούς κυρίως προς το τέλος της καλλιεργητικής περιόδου ενώ το μεγαλύτερο ποσοστό του πληθυσμού του αποτελείτο από ακμαία. Πολύ μικρός αριθμός ωιόν και προνυμφών Syrphidae και Chrysopidae βρέθηκε κατά τη διάρκεια των δειγματοληψιών, κυρίως κατά τον Αύγουστο. Το Μ. pygmaeus φαίνεται να αποτελεί τον κυριότερο παράγοντα βιολογικής αντιμετώπισης των αφίδων επί της βιομηχανικής τομάτας στην περιοχή αυτή. Επειδή δε παρατηρήθηκαν υψηλοί πληθυσμοί του κατά το τέλος της καλλιεργητικής περιόδου θα μπορούσε, ίσως, ένα μέρος τους να συλλέγει και να χρησιμοποιηθεί για αντιμετώπιση των αφίδων κυρίως σε καλλιέργειες υπό κάλυψη.Two species of aphids, Macrosiphion euphorbiae (Thomas) and Myzus persicae cae (Sulzer) (Homoptera: Aphididae) were the only ones which developed populations on processing tomato in a two year study conducted in central Greece. The aphid population structure showed that M. euphorbiae was much more abundant than M. persicae in both years. The former species peaked in August whilst the latter did not show any particular peak over the two successive years. Some species of natural enemies were recorded. Orius niger Wolff was found in low numbers scattered over a long period but mainly towards the end of the growing season, and it did not correlate with the aphid population. The rate of parasitism of M. euphorbiae by Aphelinus abdominalis Dalman and Praon volucre (Haliday) was very low and it seemed that these two parasitoid species did not have any particular effect on the aphid population suppression. Macrolophus pygmaeus Rambur was the key natural enemy and the most abundant and effective among the predators found. Its highest numbers occurred towards the end of the growing season following the aphid population peak, suggesting a numerical response of this species to its prey. A proportion of the population of M. pygmaeus occurring on tomato plants after fruit harvesting, might he collected and subsequently released in crops such as tomato, pepper and eggplant to biologically control pests in greenhouses, like aphids and whiteflies, thus contributing to the production of healthy vegetable products

Comparisons Between Alate Aphids Caught in Υellow Water Traps and Aphid Populations on Tomato Plants

Η παρακολούθηση των πτερωτών των ειδών αφίδων Myzus persicae (Sulzer) και Macrosiphum euphorbiae (Thomas) έγινε με τη βοήθεια κίτρινων παγίδων νερού τύπου Moericke, οι οποίες είχαν εγκατασταθεί σε τοματοφυτείες στην περιοχή Βοιωτίας. Το 1992, 6 παγίδες τοποθετήθηκαν σε τεμάχιο έκτασης 2 στρεμμάτων σε καλλιέργεια βιομηχανικής τομάτας (cv Η30) συνολικής έκτασης 20 στρεμμάτων στα Βάγια Βοιωτίας, από 26 Ιουνίου έως 29 Σεπτεμβρίου. Το 1993,3 παγίδες τοποθετήθηκαν στον ίδιο αγρό όπως το 1992, από τις 3 Μαΐου έως 7 Οκτωβρίου. Το ίδιο έτος, επίσης, 3 παγίδες τοποθετήθηκαν σε αγρό επιτραπέζιας τομάτας (cv Galli) στο Ακραίφνιο Βοιωτίας από 27 Μαΐου έως 1 Οκτωβρίου. Για την εκτίμηση της πληθυσμιακής πυκνότητας των αφίδων επί των φυτων, δείγματα λαμβάνονταν εβδομαδιαίως από τα πειραματικά τεμάχια των φυτειών και κατά τα δύο έτη. Τα είδη τα οποία ανέπτυξαν πληθυσμούς επί των φυτών ήταν μόνο τα Μ. persicae και Μ. euphorbiae. Η ανάλυση της παλινδρόμησης έδειξε ότι δεν υπήρχε συσχέτιση μεταξύ των πτερωτών που συνελήφθησαν στις παγίδες Moericke είτε με τα πτερωτά είτε με το σύνολο του πληθυσμού επί των φυτο5ν στη περίπτωση του Μ. persicae, σε αμφότερες τις περιοχές και κατά τα δύο έτη. Στην περίπτωση όμως του Μ. euphorbiae, η συσχέτιση μεταξύ των πτερωτών στις παγίδες και αυτών επί των φυτων ήταν σημαντική (r2=0.83) καθώς επίσης και η συσχέτιση των πτερωτων στις παγίδες και του συνολικού πληθυσμού επί των φυτών (r2=0.69) κατά το έτος 1992.Το 1993 δεν βρέθηκαν τέτοιες σημαντικές συσχετίσεις μεταξύ των ανωτέρω, λόγω των πολύ μικρών αριθμών πτερωτών που συνελήφθηκαν στις παγίδες. Αρκετά καλές συσχετίσεις βρέθηκαν, για το Μ. euphorbiae, μεταξύ των πτερωτών που συνελήφθησαν στις παγίδες, κατά την περίοδο μετανάστευσης των στην καλλιέργεια και μέχρι την πραγματοποίηση του μεγίστου, είτε με τα πτε-ρωτά επί των φυτών (r2=0.93) είτε με το συνολικό πληθυσμό επί των φυτων (r2=0.80). Η τελευταία συσχέτιση θα μπορούσε να χρησιμοποιηθεί για τον υπολογισμό του πληθυσμού του Μ. euphorbiae επί των φυτών από τις συλλήψεις των πτερωτών στις παγίδες. Η σημασία ύπαρξης τέτοιων σημαντικών συσχετίσεων μεταξύ αριθμού πτερωτών στις παγίδες και πληθυσμού των αφίδων επί των φυτών, όπως είναι προφανές, δύναται να αποβεί σε χρήσιμο «εργαλείο» στην ανάπτυξη και εφαρμογή προγραμμάτων ολοκληρωμένης αντιμετώπισης εντόμων- εχθρών της τομάτας.Aphid monitoring was conducted by means of yellow Moericke water traps placed in tomato fields in two different localities in Co Boiotia during the growing seasons in 1992 and 1993. Additionally, aphid population densities were estimated by plant sampling. Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer) were the only species which developed populations on plants. Regression analysis between the number of alates from traps with either the number of alates or the total aphid population on plants showed that there was no correlation in the case of M. persicae for both localities and years. However, there were significant relationships between the number of alates in traps and either the number of alates on plants (r2=0.83) or the total aphid population on plants (r2=0.69) for M. euphorbiae in 1992. In 1993, such significant relationships were not found for the latter species, most probably due to extremely low trap catches. Significant relationships were also found between alates in traps, during their immigration period, with either alates on plants (r2=0.93) or the total population on plants (r2=0.80) in M. euphorbiae in 1992

A Combined Rheological and Thermomechanical Analysis Approach for the Assessment of Pharmaceutical Polymer Blends

YesThe viscoelastic nature of polymeric formulations utilised in drug products imparts unique thermomechanical attributes during manufacturing and over the shelf life of the product. Nevertheless, it adds to the challenge of understanding the precise mechanistic behaviour of the product at the microscopic and macroscopic level during each step of the process. Current thermomechanical and rheological characterisation techniques are limited to assessing polymer performance to a single phase and are especially hindered when the polymers are undergoing thermomechanical transitions. Since pharmaceutical processing can occur at these transition conditions, this study successfully proposes a thermomechanical characterisation approach combining both mechanical and rheological data to construct a comprehensive profiling of polymeric materials spanning both glassy and rubbery phases. This approach has been used in this study to assess the mechanical and rheological behaviour of heterogenous polymer blends of hydroxypropyl cellulose (HPC) and hydroxypropyl methylcellulose (HPMC) over a shearing rate range of 0.1–100 s−1 and a temperature range of 30–200 °C. The results indicate that HPC and HPMC do not appear to interact when mixing and that their mixture exhibits the mechanistic properties of the two individual polymers in accordance with their ratio in the mixture. The ability to characterise the behaviour of the polymers and their mixtures before, throughout, and after the glassy to rubbery phase transition by application of the combined techniques provides a unique insight towards a quality-by-design approach to this and other polymer-based solid dosage forms, designed with the potential to accelerate their formulation process through obviating the need for multiple formulation trials

Concerted Action of Two Formins in Gliding Motility and Host Cell Invasion by Toxoplasma gondii

The invasive forms of apicomplexan parasites share a conserved form of gliding motility that powers parasite migration across biological barriers, host cell invasion and egress from infected cells. Previous studies have established that the duration and direction of gliding motility are determined by actin polymerization; however, regulators of actin dynamics in apicomplexans remain poorly characterized. In the absence of a complete ARP2/3 complex, the formin homology 2 domain containing proteins and the accessory protein profilin are presumed to orchestrate actin polymerization during host cell invasion. Here, we have undertaken the biochemical and functional characterization of two Toxoplasma gondii formins and established that they act in concert as actin nucleators during invasion. The importance of TgFRM1 for parasite motility has been assessed by conditional gene disruption. The contribution of each formin individually and jointly was revealed by an approach based upon the expression of dominant mutants with modified FH2 domains impaired in actin binding but still able to dimerize with their respective endogenous formin. These mutated FH2 domains were fused to the ligand-controlled destabilization domain (DD-FKBP) to achieve conditional expression. This strategy proved unique in identifying the non-redundant and critical roles of both formins in invasion. These findings provide new insights into how controlled actin polymerization drives the directional movement required for productive penetration of parasites into host cells

Septation of Infectious Hyphae Is Critical for Appressoria Formation and Virulence in the Smut Fungus Ustilago Maydis

Differentiation of hyphae into specialized infection structures, known as appressoria, is a common feature of plant pathogenic fungi that penetrate the plant cuticle. Appressorium formation in U. maydis is triggered by environmental signals but the molecular mechanism of this hyphal differentiation is largely unknown. Infectious hyphae grow on the leaf surface by inserting regularly spaced retraction septa at the distal end of the tip cell leaving empty sections of collapsed hyphae behind. Here we show that formation of retraction septa is critical for appressorium formation and virulence in U. maydis. We demonstrate that the diaphanous-related formin Drf1 is necessary for actomyosin ring formation during septation of infectious hyphae. Drf1 acts as an effector of a Cdc42 GTPase signaling module, which also consists of the Cdc42-specific guanine nucleotide exchange factor Don1 and the Ste20-like kinase Don3. Deletion of drf1, don1 or don3 abolished formation of retraction septa resulting in reduced virulence. Appressorium formation in these mutants was not completely blocked but infection structures were found only at the tip of short filaments indicating that retraction septa are necessary for appressorium formation in extended infectious hyphae. In addition, appressoria of drf1 mutants penetrated the plant tissue less frequently

Ancient Origin of the New Developmental Superfamily DANGER

Developmental proteins play a pivotal role in the origin of animal complexity and diversity. We report here the identification of a highly divergent developmental protein superfamily (DANGER), which originated before the emergence of animals (∼850 million years ago) and experienced major expansion-contraction events during metazoan evolution. Sequence analysis demonstrates that DANGER proteins diverged via multiple mechanisms, including amino acid substitution, intron gain and/or loss, and recombination. Divergence for DANGER proteins is substantially greater than for the prototypic member of the superfamily (Mab-21 family) and other developmental protein families (e.g., WNT proteins). DANGER proteins are widely expressed and display species-dependent tissue expression patterns, with many members having roles in development. DANGER1A, which regulates the inositol trisphosphate receptor, promotes the differentiation and outgrowth of neuronal processes. Regulation of development may be a universal function of DANGER family members. This family provides a model system to investigate how rapid protein divergence contributes to morphological complexity

Characterization of Profilin Polymorphism in Pollen with a Focus on Multifunctionality

Profilin, a multigene family involved in actin dynamics, is a multiple partners-interacting protein, as regard of the presence of at least of three binding domains encompassing actin, phosphoinositide lipids, and poly-L-proline interacting patches. In addition, pollen profilins are important allergens in several species like Olea europaea L. (Ole e 2), Betula pendula (Bet v 2), Phleum pratense (Phl p 12), Zea mays (Zea m 12) and Corylus avellana (Cor a 2). In spite of the biological and clinical importance of these molecules, variability in pollen profilin sequences has been poorly pointed out up until now. In this work, a relatively high number of pollen profilin sequences have been cloned, with the aim of carrying out an extensive characterization of their polymorphism among 24 olive cultivars and the above mentioned plant species. Our results indicate a high level of variability in the sequences analyzed. Quantitative intra-specific/varietal polymorphism was higher in comparison to inter-specific/cultivars comparisons. Multi-optional posttranslational modifications, e.g. phosphorylation sites, physicochemical properties, and partners-interacting functional residues have been shown to be affected by profilin polymorphism. As a result of this variability, profilins yielded a clear taxonomic separation between the five plant species. Profilin family multifunctionality might be inferred by natural variation through profilin isovariants generated among olive germplasm, as a result of polymorphism. The high variability might result in both differential profilin properties and differences in the regulation of the interaction with natural partners, affecting the mechanisms underlying the transmission of signals throughout signaling pathways in response to different stress environments. Moreover, elucidating the effect of profilin polymorphism in adaptive responses like actin dynamics, and cellular behavior, represents an exciting research goal for the future

Mitochondrial dysfunction and autism: Comprehensive genetic analyses of children with autism and mtDNA deletion

Additional file 1: Table S1. Investigated genes responsible for mtDNA maintenance (intergenomic NGS panel)