Beauveria bassiana strain ATCC 74040 (Naturalis®), a valuable tool for the control of the cherry fruit fly (Rhagoletis cerasi)

Naturalis® is a bioinsecticide based on living conidiospores of the naturally occuring Beauveria bassiana strain ATCC 74040. The entomopathogenic fungus acts primarily by contact: once attached to the insect’s cuticle, the conidiospores germinate producing penetration hyphae, which enter and proliferate inside the insect’s body. The fungus invades and feeds on its host, causing its death due to dehydration and/or depletion of nutrients. Several years of laboratory, semi-field and field studies showed that also Tephritid flies (Ceratitis capitata, Rhagoletis cerasi, Bactrocera oleae) are susceptible to infection by B. bassiana strain ATCC 74040. The results of efficacy trials conducted in 2004-05 are reported. Naturalis was tested both alone and in an integrated pest management strategy. The product showed high efficacy in controlling R. cerasi, comparable to or higher than that of the chemical reference treatment. The B. bassiana-based product Naturalis can thus be considered an efficient tool for the control of the cherry fruit fly

Effectiveness of entomopathogenic nematodes in the control of Cydia pomonella larvae in Northern Italy

Since 2006, a large scale research on the effectiveness of entomopathogenic nematodes (EPN) in the control of codling moth (CM), Cydia pomonella, overwintering larvae has been performed on about 35 ha of pear orchards per year in Emilia-Romagna, Northern Italy. Steinernema carpocapsae and Steinernema feltiae activity was checked after spray applications of EPNs to the trunk and branches. In 2006, the treatment was applied either in spring or in autumn at different doses, before CM pupation; in 2007 the EPN treatment was applied only in autumn at 1.5 x 109 I.J. ha –1. Every year it was distributed by means of a conventional mist blower. The larval mortality was assessed directly on sentinel larvae in card boards on the trunks and indirectly on the eggs laid by the females of the first CM generation in spring. Moreover, each year, a trial was performed applying only S. carpocapsae on sentinel larvae with the aim of testing this nematode at suitable temperatures but at different water volumes. The CM sentinel larvae were effectively parasitized after autumnal EPN application. Moreover, the egg assessment demonstrated a good decrease in CM population in spring 2007, when EPNs had been applied at the best weather conditions (t° 12-14 °C and rain) in the previous autumn

Mutations of penicillin acylase residue B71 extend substrate specificity by decreasing steric constraints for substrate binding

Two mutant forms of penicillin acylase from Escherichia coli strains, selected using directed evolution for the ability to use glutaryl-L-leucine for growth [Forney, Wong and Ferber (1989) Appl. Environ. Microbiol. 55, 2550-2555], are changed within one codon, replacing the B-chain residue Phe(B71) with either Cys or Leu. Increases of up to a factor of ten in k(cat)/K-m values for substrates possessing a phenylacetyl leaving group are consistent with a decrease in K-s. Values of k(cat/)K(m) for glutaryl-L-leucine are increased at least 100-fold. A decrease in k(cat)/K-m for the CySB71 mutant with increased pH is consistent with binding of the uncharged glutaryl group. The mutant proteins are more resistant to urea denaturation monitored by protein fluorescence, to inactivation in the presence of substrate either in the presence of urea or at high pH, and to heat inactivation. The crystal structure of the Leu(B71) mutant protein, solved to 2 X resolution, shows a flip of the side chain of Phe(B256) into the periphery of the catalytic centre, associated with loss of the pi-stacking interactions between Phe(B256) and Phe(B71). Molecular modelling demonstrates that glutaryl-L-leucine may bind with the uncharged glutaryl group in the S-1 subsite of either the wild-type or the Leu(B71) mutant but with greater potential freedom of rotation of the substrate leucine moiety in the complex with the mutant protein. This implies a smaller decrease in the conformational entropy of the substrate on binding to the mutant proteins and consequently greater catalytic activity

Adhesive organ regeneration in <i>Macrostomum lignano</i>

BackgroundFlatworms possess pluripotent stem cells that can give rise to all cell types, which allows them to restore lost body parts after injury or amputation. This makes flatworms excellent model systems for studying regeneration. In this study, we present the adhesive organs of a marine flatworm as a simple model system for organ regeneration. Macrostomum lignano has approximately 130 adhesive organs at the ventral side of its tail plate. One adhesive organ consists of three interacting cells: one adhesive gland cell, one releasing gland cell, and one modified epidermal cell, called an anchor cell. However, no specific markers for these cell types were available to study the regeneration of adhesive organs.ResultsWe tested 15 commercially available lectins for their ability to label adhesive organs and found one lectin (peanut agglutinin) to be specific to adhesive gland cells. We visualized the morphology of regenerating adhesive organs using lectin- and antibody staining as well as transmission electron microscopy. Our findings indicate that the two gland cells differentiate earlier than the connected anchor cells. Using EdU/lectin staining of partially amputated adhesive organs, we showed that their regeneration can proceed in two ways. First, adhesive gland cell bodies are able to survive partial amputation and reconnect with newly formed anchor cells. Second, adhesive gland cell bodies are cleared away, and the entire adhesive organ is build anew.ConclusionOur results provide the first insights into adhesive organ regeneration and describe ten new markers for differentiated cells and tissues in M. lignano. The position of adhesive organ cells within the blastema and their chronological differentiation have been shown for the first time. M. lignano can regenerate adhesive organs de novo but also replace individual anchor cells in an injured organ. Our findings contribute to a better understanding of organogenesis in flatworms and enable further molecular investigations of cell-fate decisions during regeneration

Sequencing of folding events in Go-like proteins

We have studied folding mechanisms of three small globular proteins: crambin (CRN), chymotrypsin inhibitor 2 (CI2) and the fyn Src Homology 3 domain (SH3) which are modelled by a Go-like Hamiltonian with the Lennard-Jones interactions. It is shown that folding is dominated by a well-defined sequencing of events as determined by establishment of particular contacts. The order of events depends primarily on the geometry of the native state. Variations in temperature, coupling strengths and viscosity affect the sequencing scenarios to a rather small extent. The sequencing is strongly correlated with the distance of the contacting aminoacids along the sequence. Thus $\alpha$-helices get established first. Crambin is found to behave like a single-route folder, whereas in CI2 and SH3 the folding trajectories are more diversified. The folding scenarios for CI2 and SH3 are consistent with experimental studies of their transition states.Comment: REVTeX, 12 pages, 11 EPS figures, J. Chem. Phys (in press

Cerebral Localized Marginal Zone Lymphoma Presenting as Hypothalamic-Pituitary Region Disorder

Introduction: Marginal zone B-cell lymphoma is a rare disease which can be considerably difficult to recognize and diagnose when signs of systemic involvement are absent. Case Presentation: We report the case of a 57-year-old woman with initial olfactory disturbance, followed by psychosis, diabetes insipidus and hypothalamic eating disorder as an uncommon clinical presentation of marginal zone B-cell lymphoma. Conclusion: Marginal zone B-cell lymphoma should be considered as a potential differential diagnosis in patients with hypothalamic disturbances

sNASP and ASF1A function through both competitive and compatible modes of histone binding

Histone chaperones are proteins that interact with histones to regulate the thermodynamic process of nucleosome assembly. sNASP and ASF1 are conserved histone chaperones that interact with histones H3 and H4 and are found in a multi-chaperoning complex in vivo. Previously we identified a short peptide motif within H3 that binds to the TPR domain of sNASP with nanomolar affinity. Interestingly, this peptide motif is sequestered within the known ASF1–H3–H4 interface, raising the question of how these two proteins are found in complex together with histones when they share the same binding site. Here, we show that sNASP contains at least two additional histone interaction sites that, unlike the TPR–H3 peptide interaction, are compatible with ASF1A binding. These surfaces allow ASF1A to form a quaternary complex with both sNASP and H3–H4. Furthermore, we demonstrate that sNASP makes a specific complex with H3 on its own in vitro, but not with H4, suggesting that it could work upstream of ASF1A. Further, we show that sNASP and ASF1A are capable of folding an H3–H4 dimer in vitro under native conditions. These findings reveal a network of binding events that may promote the entry of histones H3 and H4 into the nucleosome assembly pathway

Co-localization of CENP-C and CENP-H to discontinuous domains of CENP-A chromatin at human neocentromeres

The distribution of centromeric chromatin-associated proteins across human neocentromeric DNA shows that this chromatin consists of several CENP-A-containing sub-domains