Adrenomedullin is a novel marker of tumor progression in neuroendocrine carcinomas.

Adrenomedullin is a multi-functional polypeptide hormone. Its involvement in angiogenesis and vasodilator action support the hypothesis that adrenomedullin may be a secretory product of neuroendocrine tumors and contribute to tumor progression. Plasma levels of adrenomedullin were measured by radioimmunoassay in 46 patients with neuroendocrine carcinomas of the gastroenteropancreatic and bronchial system. Tissue expression of adrenomedullin was studied using monoclonal antibodies on pretreated paraffin embedded tissues in a group of 31 patients. Adrenomedullin plasma levels were significantly elevated in patients compared to healthy age-matched controls (p < 0.001). The highest plasma levels were found in patients with neuroendocrine carcinomas of bronchial, midgut and unknown origin. Patients with progressive disease had higher plasma levels than patients with stable disease (p < 0.001). Of the examined tumor samples, 55 % showed cytoplasmic staining for adrenomedullin > 5 % of the total tumor area. Plasma levels and tissue expression of adrenomedullin did not correlate with functional activity of the tumors or presence of the carcinoid syndrome, but did with tumor progression (p < 0.001 and p < 0.014). In conclusion, plasma and tissue expression of the angiogenic peptide adrenomedullin are predictive of tumor progression in patients with neuroendocrine carcinomas. Adrenomedullin might represent a useful prognostic marker in patients with neuroendocrine carcinomas.     

Comparative response to citrus foliage and citrus fruit odour by wild and mass-reared sterile Mediterranean fruit fly males of a genetic sexing strain

In greenhouse behavioural assessments conducted at Seibersdorf, Austria that allowed flies the choice of different types of potted host trees and plants, it was found that mature laboratory mass-reared Mediterranean fruit fly males, Ceratitis capitata (Wied), (Dipt. Tephritidae), strain Vienna-42 (temperature-sensitive lethal genetic sexing strain) showed the same preference for orange foliage, over other plants types and parts, as wild males. They aggregated in leks, released pheromone, and courted approaching females almost exclusively on orange foliage. Even though a number of other trees and plants were available to Vienna-42 males, less than 1% of these sexual activities occurred on the foliage or other plant parts of non-Citrus trees and not a single mating occurred there. In choice tests carried out in Chios, Greece in large field cages housing naturally planted orange trees, it was determined that mature and sterile Mediterranean fruit fly males of the same sexing strain responded to the odour emanating from the flavedo (due to superficial cuts made in the fruit peel containing the oil glands) of ripening sweet, sour oranges and lemons, in a similar intensity, order of fruit preference and time of day as did mature males of the local wild population. Males of both strains were frequently observed contacting with their mouth parts the oils exuding from the cuts made in the flavedo of the orange peel, or exhibiting homosexual activity on, or near the cuts. The results show that mass-reared, sterile males of the Vienna-42, genetic sexing strain behave in a comparable way to wild males in an important component of habitat location (odour of host foliage and host fruit) and hence are competitive with them in these respects. None of the standard international quality control tests for sterile Mediterranean fruit flies evaluates this important habitat location behaviour, which is a prerequisite for the successful encounter of the sexes in a sterile release programme.     

In vitro studies on the role of the peripheral-type benzodiazepine receptor in steroidogenesis

In vitro studies using isolated cells, mitochondria and submitochondrial fractions demonstrated that in steroid synthesizing cells, the peripheral-type benzodiazepine receptor (PBR) is an outer mitochondrial membrane protein, preferentially located in the outer/inner membrane contact sites, involved in the regulation of cholesterol transport from the outer to the inner mitochondrial membrane, the rate-determining step in steroid biosynthesis. Mitochondrial PBR ligand binding characteristics and topography are sensitive to hormone treatment suggesting a role of PBR in the regulation of hormone-mediated steroidogenesis. Targeted disruption of the PBR gene in Leydig cells in vitro resulted in the arrest of cholesterol transport into mitochondria and steroid formation; transfection of the mutant cells with a PBR cDNA rescued steroidogenesis demonstrating an obligatory role for PBR in cholesterol transport. Molecular modeling of PBR suggested that it might function as a channel for cholesterol. This hypothesis was tested in a bacterial system devoid of PBR and cholesterol. Cholesterol uptake and transport by these cells was induced upon PBR expression. Amino acid deletion followed by site-directed mutagenesis studies and expression of mutant PBRs demonstrated the presence in the cytoplasmic carboxy-terminus of the receptor of a cholesterol recognition/interaction amino acid consensus sequence. This amino acid sequence may help for recruiting the cholesterol coming from intracellular sites to the mitochondria.     

Obligate annual and successive facultative diapause establish a bet‐hedging strategy of Rhagoletis cerasi (Diptera: Tephritidae) in seasonally unpredictable environments

To cope with temporal and spatial heterogeneity of habitats, herbivorous insects in the temperate zone usually enter diapause that facilitates synchronization of their life cycle with specific stages of host plants, such as fruit ripening. In the present study, we address those factors regulating dormancy responses as part of a ‘longer strategy’ to persist and thrive in temperate environments, focusing on Rhagoletis cerasi, a univoltine, oligophagous species, which overwinters as pupae and emerges when host fruits are available for oviposition at local scale. To ensure population survival and reproduction at habitats with ecological heterogeneity, R. cerasi has evolved a sophisticated diapause strategy based on a combination of local adaptation and diversified bet‐hedging strategies. Diapause duration is determined both by (i) the adaptive response to local host fruit phenology patterns (annual diapause) and (ii) the plastic responses to unpredictable inter‐annual (temporal) climatic variability that drives a proportion of the populations to extend dormancy by entering a second, successive, facultative cycle of prolonged diapause as part of a bet‐hedging strategy. Besides the dormant periods, post‐diapause development (which varies among populations) exerts ‘fine tune’ adjustments that assure synchronization and may correct possible errors. Adults emerging from pupae with prolonged diapause are larger in body size compared with counterparts emerging during the first year of diapause. However, female fecundity rates are reduced, followed by an extended post‐oviposition period, whereas adult longevity remains unaffected. Overall, it appears that R. cerasi populations are adapted to ecological conditions of local habitats and respond plastically to unpredictable environmental (climatic) conditions.     

VCP/p97 cooperates with YOD1, UBXD1 and PLAA to drive clearance of ruptured lysosomes by autophagy

Rupture of endosomes and lysosomes is a major cellular stress condition leading to cell death and degeneration. Here, we identified an essential role for the ubiquitin‐directed AAA‐ATPase, p97, in the clearance of damaged lysosomes by autophagy. Upon damage, p97 translocates to lysosomes and there cooperates with a distinct set of cofactors including UBXD1, PLAA, and the deubiquitinating enzyme YOD1, which we term ELDR components for Endo‐Lysosomal Damage Response. Together, they act downstream of K63‐linked ubiquitination and p62 recruitment, and selectively remove K48‐linked ubiquitin conjugates from a subpopulation of damaged lysosomes to promote autophagosome formation. Lysosomal clearance is also compromised in MEFs harboring a p97 mutation that causes inclusion body myopathy and neurodegeneration, and damaged lysosomes accumulate in affected patient tissue carrying the mutation. Moreover, we show that p97 helps clear late endosomes/lysosomes ruptured by endocytosed tau fibrils. Thus, our data reveal an important mechanism of how p97 maintains lysosomal homeostasis, and implicate the pathway as a modulator of degenerative diseases.     

Age structure changes and extraordinary lifespan in wild medfly populations

The main purpose of this study was to test the hypotheses that major changes in age structure occur in wild populations of the Mediterranean fruit fly (medfly) and that a substantial fraction of individuals survive to middle age and beyond (> 3-4 weeks). We thus brought reference life tables and deconvolution models to bear on medfly mortality data gathered from a 3-year study of field-captured individuals that were monitored in the laboratory. The average time-to-death of captured females differed between sampling dates by 23.9, 22.7, and 37.0 days in the 2003, 2004, and 2005 field seasons, respectively. These shifts in average times-to-death provided evidence of changes in population age structure. Estimates indicated that middle-aged medflies (> 30 days) were common in the population. A surprise in the study was the extraordinary longevity observed in field-captured medflies. For example, 19 captured females but no reference females survived in the laboratory for 140 days or more, and 6 captured but no reference males survived in the laboratory for 170 days or more. This paper advances the study of aging in the wild by introducing a new method for estimating age structure in insect populations, demonstrating that major changes in age structure occur in field populations of insects, showing that middle-aged individuals are common in the wild, and revealing the extraordinary lifespans of wild-caught individuals due to their early life experience in the field.     

Computational design of novel fullerene analogues as potential HIV-1 PR inhibitors: Analysis of the binding interactions between fullerene inhibitors and HIV-1 PR residues using 3D QSAR, molecular docking and molecular dynamics simulations

A series of experimentally reported as well as computationally designed monoadducts and bisadducts of [60]fullerene analogues have been used in order to analyze the binding interactions between fullerene based inhibitors and HIV-1 PR employing docking studies. MD simulations of ligand-free and the inhibitor bound HIV-1 PR systems complemented the above studies and provided proper input structure of HIV-1 PR in docking simulations. The obtained results revealed a different orientation of the beta-hairpin flaps at these two systems. In inhibitor bound system, the flaps of the enzyme are pulled in toward the bottom of the active site (the closed form) while, in ligand-free system flaps shifted away from the dual Asp25 catalytic site and this system adopts a semi-open form. The structural analysis of these systems at catalytic and flexible flap regions of the HIV-1 PR through the simulation, assisted in understanding the structural preferences of these regions, as well as, the adopted orientations of fullerene derivatives within the active site of the enzyme. Five different combinations of steroelectronic fields of 3D QSAR/CoMSIA models were obtained from the set of biologically evaluated and computationally designed fullerene derivatives (training set=43, test set=6) in order to predict novel compounds with improved inhibition effect. The best 3D QSAR/CoMSIA model yielded a cross validated r(2) value of 0.739 and a non-cross validated r(2) value of 0.993. The derived model indicated the importance of steric (42.6%), electrostatic (12.7%), H-bond donor (16.7%) and H-bond acceptor (28.0%) contributions. The derived contour plots together with de novo drug design were then used as pilot models for proposing the novel analogues with enhanced binding affinities. Such structures may trigger the interest of medicinal chemists for novel HIV-1 PR inhibitors possessing higher bioactivity.     

Genetic and cytogenetic analysis of the fruit fly Rhagoletis cerasi (Diptera: Tephritidae).

The European cherry fruit fly, Rhagoletis cerasi, is a major agricultural pest for which biological, genetic, and cytogenetic information is limited. We report here a cytogenetic analysis of 4 natural Greek populations of R. cerasi, all of them infected with the endosymbiotic bacterium Wolbachia pipientis. The mitotic karyotype and detailed photographic maps of the salivary gland polytene chromosomes of this pest species are presented here. The mitotic metaphase complement consists of 6 pairs of chromosomes, including one pair of heteromorphic sex chromosomes, with the male being the heterogametic sex. The analysis of the salivary gland polytene complement has shown a total of 5 long chromosomes (10 polytene arms) that correspond to the 5 autosomes of the mitotic nuclei and a heterochromatic mass corresponding to the sex chromosomes. The most prominent landmarks of each polytene chromosome, the "weak points", and the unusual asynapsis of homologous pairs of polytene chromosomes at certain regions of the polytene elements are also presented and discussed.