NEW PUBLICATIONS
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dicembre 2011
The effect of local environmental heterogeneity on species diversity of alpine dung beetles (Coleoptera: Scarabaeidae)
Matteo Negro, Claudia Palestrini, Maria Teresa Giraudo and Antonio Rolando
The relative effects of two components of mountain environmental heterogeneity, altitude (1500, 1700 and 2000 m a.s.l.) and habitat (pastures, coniferous forests, wet meadows, scrub and anthropogenic woods) on the diversity of dung beetles in an Italian alpine valley were determined. The additive gamma diversity analysis indicated that differences among habitats (ßH) were always smaller than those among altitudes (ßA), irrespective of the measures used; it also showed that the contribution of ßA to ?-diversity was higher than expected by chance for all the measures of species diversity used, whereas the contribution of ßH was significantly higher in the case of one measure only. Generalized linear models confirmed that altitude was the most important factor associated with local diversity, with all the diversity parameters considered progressively and significantly increasing with increasing altitude. Indicator species analyses revealed that dung beetle altitudinal and habitat diversity patterns depended on local choice of species, with preferences for altitudinal levels being more numerous and apparent than those for habitats. Despite the minor effect of habitat differences, comparing a three-habitat with a single-habitat scenario it was possible to demonstrate that greater habitat heterogeneity is associated with a significantly greater diversity of dung beetles. This study suggests that preservation of local environmental heterogeneity by means of traditional pastoral activities should be encouraged as a means of conserving the diversity of dung beetle
species in the Alps.
Eur. J. Entomol. 108: 91–98, 2011
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dicembre 2011
The Impact of Overgrazing on Dung Beetle Diversity in the Italian Maritime Alps
Matteo Negro, Antonio Rolando, and Claudia Palestrini
Dung beetles (Coleoptera: Scarabaeidae) are undoubtedly the most typical and ecologically relevant insects of grazed alpine habitats because they provide valuable ecological services such as biological pest control and soil fertilization. Despite the great ecological contribution of these insects to pasture ecosystem functioning, little is known about their direct or indirect relationships with pastoral activities. The main aim of the study was to assess whether dung beetle diversity was inßuenced by different intensities of cattle grazing. Dung beetle communities of two adjacent alpine valleys within the Maritime Alps Natural Park (north-western Italian Alps), representing overgrazed and ungrazed pastures, were studied by pitfall trapping. A hierarchical design (three levels: valleys, transects, and replicates) was established for additive partitioning of ?-diversity and Indicator Species Analysis. Evenness and Shannon diversity were signiÞcantly higher at the ungrazed than at the overgrazed site because abundances were much more evenly distributed at the former than at the latter site (where one species was dominant over all the others). Dung beetle abundance and species richness of the overgrazed graminaceous pasture vegetation types were in most cases signiÞcantly lower than those of the ungrazed nongraminaceous vegetation type. In the additive partitioning of -diversity analysis relative to the whole study area, the randomization procedure indicated that the contribution of β to ?-diversity was signiÞcantly different from that expected by chance, suggesting that one or more environmental factors has intervened to change the partition of total diversity in the system considered. The analysis of the preferences and Þdelity of species (Indicator Species Analysis) showed that only one species chose overgrazed pastures; all the others positively selected the ungrazed site, or the only ungrazed pasture vegetation type (Rumicetum alpini Beger) occurring at the overgrazed site. Results conformed to evidences that overgrazing represents a serious threat to the conservation of alpine dung beetles. To conserve local dung beetle assemblages, especially in protected areas, cattle overgrazing should be avoided. This does not mean, however, that pastoral activities are incompatible with biodiversity conservation. The contemporaneous presence of wild ungulates and low intensity extensive pastoral activities may be useful to preserve both local dung beetle assemblages and alpine pasture ecosystems.
Environmental Entomology, Volume 40, Number 5, October 2011 , pp. 1081-1092(12)
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dicembre 2011
Population extinctions in the italian diurnal lepidoptera: an analysis of possible causes
Simona Bonelli, Cristiana Cerrato, Nicola Loglisci, Emilio Balletto
In depth studies of patterns of extinction are fundamental to understand species vulnerability, in particular when population extinctions are not driven by habitat loss, but related to subtle changes in habitat quality and are due to “unknown causes”. We used a dataset containing over 160,000 non-duplicate individual records of occurrence (referred to 280 butterflies and 43 zygenid moths), and their relative extinction data, to carry out a twofold analysis. We identified ecological preferences that influence extinction probability, and we analysed if all species were equally vulnerable to the same factors. Our analyses revealed that extinctions were non-randomly distributed in space and time, as well as across species. Most of the extinctions were recorded in 1901-1950 and, as expected, populations at their range edges were more prone to become extinct for non-habitat-related causes. Ecological traits were not only unequally distributed between extinction and non-extinction events, but also not all ecological features had the same importance in driving population vulnerability. Hygrophilous and nemoral species were the most likely to experience population losses and the most prone to disappear even when their habitat remained apparently unchanged. Species vulnerability depends on both ecological requirements and threat type: in fact, each species showed a distinct pattern of vulnerability, depending on threats. We concluded that the analysis may be an important step to prevent butterfly declines: species that are strongly suffering due to “unknown changes” are in clear and urgent need of more detailed auto-ecological studies.
Journal of Insect Conservation (2011), Volume 15, Number 6, 879-890
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dicembre 2011
To lay or not to lay: oviposition of Maculinea arion in relation to Myrmica ant presence and host plant phenology
Dario Patricelli, Francesca Barbero, Valentina La Morgia, Luca P. Casacci, Magdalena Witek, Emilio Balletto, Simona Bonelli
The choices made by ovipositing female butterflies play a key role in the survival of their offspring and consequently in the persistence of butterfly populations. These choices are even more crucial in the case of obligate myrmecophilous organisms such as Maculinea butterflies with larvae that, after a phytophagous period, need to be adopted by Myrmica ants to complete their life cycle. Because the worker ants’ foraging range is limited, selecting an ’ideal’ oviposition site requires that both the phenological stage of the larval food plant (short-term larval fitness) and the presence of suitable host ants (long-term larval fitness) are taken into account. Whether the female’s selection of a valuable oviposition plant is influenced by the closeness of a Myrmica nest is unclear. We studied the oviposition behaviour of a Maculinea arion population exploiting Origanum vulgare as a host plant. By following females, we collected phenological data on the visited plants that were either ’chosen’ for oviposition or ’avoided’ (flowers were visited and evaluated, but received no eggs), and we assessed the presence of Myrmica ants in the vicinity of each plant. Results suggest that plants are selected by M. arion females on the basis of their bud phenology and the presence of host ants and not of other environmental features. We thus hypothesize the evolution of an adaptive mechanism that affords females of this strictly myrmecophilous butterfly the ability to ensure the long-term survival of their brood by selecting host plants growing near a Myrmica nest.
Animal Behaviour 82 (2011) 791-799
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dicembre 2011
Landscape changes caused by high altitude ski-pistes affect bird species richness and distribution in the Alps
Enrico Caprio, Dan E. Chamberlain, Marco Isaia, Antonio Rolando
There is a paucity of research on the wider landscape-level effects of ski-piste construction on alpine fauna. In this study, the response of alpine bird communities to the landscape changes induced by the construction of ski-pistes was investigated in the western Italian Alps. The aims were: (i) to test the hypothesis that ski-pistes have a detrimental effect on alpine grassland bird communities at a landscape-scale; and, (ii) to model local probability distributions of bird species according to different scenarios of ski-piste restoration and ski-piste proliferation above the treeline. Species richness and presence/absence data from point counts were analyzed in relation to GIS-derived landscape variables based on a 16 ha hexagon grid. Predictive variables were selected through the LASSO model selection procedure, and logistic regression was used to estimate the probability of occurrence of each species in each hexagon. Grassland species richness, and probability of occurrence of water pipit, wheatear and black redstart, significantly decreased with increasing extent of ski-piste edge. Length of ski-piste edge was in the set of best models considering a large range of habitat and landscape predictors, and are therefore clearly features that exert a strong negative effect on high alpine grassland bird communities. Predictions of species occurrence were made by applying the models to different scenarios of habitat change. These showed predicted detrimental impacts of a relatively small 10% increase in ski-piste extent, but also that grassland restoration on existing ski-pistes could result in significantly increased occurrence rates of alpine grassland species. This study suggests that ski-pistes are perceived by birds as detrimental features of the alpine landscape. To minimize their impact, new, environmentally–friendly ways of constructing pistes should be developed, which could include habitat restoration and management to obtain a level of grass cover such that edges of ski-pistes are no longer perceived by birds.
Biological Conservation Volume 144, Issue 12, December 2011, Pages 2958-2967
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10 ottobre 2011
Iron-based redox centres of reductase and oxygenase components of phenol hydroxylase from A. radioresistens: a redox chain working at highly positive redox potentials
Francesca Valetti, Andrea Fantuzzi, Sheila J. Sadeghi and Gianfranco Gilardi *
This is the first report of the direct electrochemistry of the reductase (PHR) and oxygenase (PHO) components of phenol hydroxylase from Acinetobacter radioresistens S13 studied by cyclic and differential pulse voltammetry. The PHR contains one 2Fe2S cluster and one FAD that mediate the transfer of electrons from NAD(P)H to the non-heme diiron cluster of PHO. Cyclic and differential pulse voltammetry (CV and DPV) on glassy carbon showed two redox pairs with midpoint potentials at +131.5 ± 13 mV and −234 ± 3 mV versus normal hydrogen electrode (NHE). The first redox couple is attributed to the FeS centre, while the second one corresponds to free FAD released by the protein. DPV scans on native and guanidinium chloride treated PHR highlighted the presence of a split signal (ΔE ≈ 100 mV) attributed to heterogeneous properties of the 2Fe2S cluster interacting with the electrode, possibly due to the presence of two protein conformers and consistently with the large peak-to-peak separation and the peak broadening observed in CV. DPV experiments on gold electrodes performed on PHO confirm a consistently higher reduction potential at +396 mV vs. NHE. The positive redox potentials measured by direct electrochemistry for the FeS cluster in PHR and for the non-heme diiron cluster of PHO show that the entire phenol hydroxylase system works at higher potentials than those reported for structurally similar enzymes, for example methane monooxygenases.
Metallomics. 2011 Oct 10
http://pubs.rsc.org/en/Content/ArticleLanding/2012/MT/C1MT00136A
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22 settembre 2011
Engineering new metabolic capabilities in bacteria: lessons from recombinant cellulolytic strategies
Roberto Mazzoli, Cristina Lamberti and Enrica Pessione
Cellulose waste biomass is the most attractive substrate for ‘biorefinery strategies’ producing high-value products (e.g. fuels or plastics) by fermentation. However, traditional biomass bioconversions are economically inefficient multistep processes. Thus far, no microorganisms able to perform single-step fermentation into products (consolidated bioprocessing; CBP) have been isolated. Metabolic engineering is currently employed to develop recombinant microorganisms suitable for CBP. The heterologous expression of extracellular proteins (e.g. cellulases or hemicellulases) is the key feature of recombinant cellulolytic strategies, conferring cellulolytic ability to microorganisms exhibiting high product yields and titers. Although more molecular tools are becoming available, efficient heterologous expression of secreted proteins is still a challenge. The present review summarizes both bottlenecks and solutions of organism engineering for biomass biorefinery strategies.
Trends Biotechnol. 2011 Sep 17. [Epub ahead of print]
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24 agosto 2011
Direct electrochemistry of an [FeFe]-hydrogenase on a TiO2 Electrode
Simone Morra, Francesca Valetti, Sheila J. Sadeghi,Paul W. King, Toby Meyer and Gianfranco Gilardi
[FeFe]-hydrogenases are efficient natural catalysts that can be exploited for hydrogen production. Immobilization of the recombinant [FeFe]-hydrogenase CaHydA was achieved on an anatase TiO2 electrode, a crystalline semiconductor material that can be nanostructured. TiO2 is mainly light transparent and can be photosensitized with the desired features; thus it is an excellent candidate for the use in photo electrochemical devices. This work demonstrates for the first time that it is possible to immobilize the [FeFe]-hydrogenase CaHydA on anatase TiO2, with productive electron transfer. The resulting stationary electrode can produce molecular hydrogen with an efficiency of 70% at -741 mV vs. NHE. It is also demonstrated that an additional coating with the proton conductive polymer Nafion hinders protein desorption and results in increased electrode stability.
The TiO2 electrode with immobilized CaHydA is a promising hydrogen evolving cathode that can be used for the development of bio-inspired artificial devices able to store energy in a valuable fuel.
Chem Commun (Camb). 2011 Sep 20;47(38):10566-8. Epub 2011 Aug 24.
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22 agosto 2011
Direct spectroscopic evidence for binding of anastrozole to the iron heme of human aromatase. Peering into the mechanism of aromatase inhibition
Sara Maurelli, Mario Chiesa, Elio Giamello, Giovanna Di Nardo, Valentina E. V. Ferrero, Gianfranco Gilardi and Sabine Van Doorslaer
Aromatase (CYP19A1), is a microsomal cytochrome P450 catalysing the conversion of androgens to estrogens. Non-steroidal inhibitors, such as anastrozole, are important drugs in breast cancer therapy. Using hyperfine sublevel correlation (HYSCORE) spectroscopy we provide the first experimental evidence of the binding of anastrozole to the iron heme of human aromatase.
Chem Commun (Camb). 2011 Sep 20;47(38):10737-9. Epub 2011 Aug 22
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17 agosto 2011
Hydrogen sulfide promotes calcium signals and migration in tumor-derived endothelial cells
Pupo Emanuela, Fiorio Pla Alessandra, Avanzato Daniele, Moccia Francesco, Avelino Cruz José-Everardo, Tanzi Franco, Merlino Annalisa, Mancardi Daniele, Munaron Luca.
Hydrogen sulfide (H2S) is a gasotransmitter that plays several roles in various tissues, including the cardiovascular system. Because it has been recently proposed to act as a mediator of angiogenesis progression, here we investigate the effects of H2S in a well-established model of tumor angiogenesis: endothelial cells obtained from human breast carcinoma (B-TECs). Ca2+ imaging and patch-clamp experiments reveal that acute perfusion with NaHS, a widely employed H2S donor, activates cytosolic calcium (Cac) increase, as well as potassium and nonselective cationic currents, in B-TECs. Stimulation with NaHS in the same concentration range (1 nM–200 μM) evoked Cac signals also in “normal” human microvascular endothelial cells (HMVECs), but the amplitude was significantly lower. Moreover, although NaHS failed to promote either migration or proliferation on HMVECs, B-TEC migration was enhanced at low-micromolar NaHS concentrations (1–10 μM). Remarkably H2S mediates tumor proangiogenic signaling triggered by vascular endothelial growth factor (VEGF). B-TECs pretreated with DL-propargylglycine (5 mM, 30 min), an inhibitor of the H2S-producing enzyme cystathionine γ-lyase, showed drastically reduced migration and Cacsignals induced by VEGF (20 ng/ml). We conclude that H2S plays a role in proangiogenic signaling of tumor-derived but not normal human ECs. Furthermore the ability of this gasotransmitter to interfere with B-TEC responsiveness to VEGF suggests that it could be an interesting target for antiangiogenic strategies in tumor treatment.
Free Radic Biol Med. 2011 Nov 1;51(9):1765-73. Epub 2011 Aug 17
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10 agosto 2011
Xenoestrogens elicit a modulation of endocannabinoid system and estrogen receptors in 4NP treated goldfish, Carassius auratus.
Valentina Pomatto, Francesco Palermo, Gilberto Mosconi, Erika Cottone, Paolo Cocci, Massimo Nabissi, Luca Borgio, Alberta M. Polzonetti-Magni, Maria Fosca Franzoni
Based on pharmacological, behavioral and neuroanatomical studies, the endocannabinoids appear to be pivotal in some important neuroendocrine regulations of both vertebrates and invertebrates. Interestingly, a well developed endocannabinoid system was recently demonstrated by us in different bonyfish brain areas which control reproduction, energy balance and stress. Fish in particular are very sensitive to different types of stressors which can heavily affect their reproductive activity and negatively reverberate on aquaculture. Since recent new data have been reported on endocrine disruptors (EDs) impact on zebrafish receptor CB1 expression, in the present research we have investigated the response of the endocannabinoid system to acute treatment with an environmental stressor such as the xenoestrogen nonylphenol (4NP) in the brain and peripheral tissues of the goldfish Carassius auratus. First of all the estrogenic effects induced by 4NP were demonstrated by a dose-dependent increase of plasma levels and gene expression of the biomarker vitellogenin, then changes in cannabinoid receptors and anandamide degradative enzyme, the fatty acid amide hydrolase (FAAH), were analysed by means of Real Time PCR. As the exposure to EDs may lead to an activation of estrogen receptors and affects the Aromatase (AROB) transcription, changes in mRNA levels for ER subtypes and AROB were also evaluated. Our results confirm in goldfish the effect of 4NP on ERα and ERβ1 receptors and point out a different sensitivity of CB1 and CB2 for this compound, suggesting distinct roles of these cannabinoid receptors in some adaptive processes to contrast stress induced by xenoestrogen exposure..
General and Comparative Endocrinology
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15 luglio 2011
Daz- and Pumilio-like genes are asymmetrically localized in Pelophylax (Rana) oocytes and are expressed during early spermatogenesis
Silvia Marracci, Valentina Michelotti, Claudio Casola, Cristina Giacoma, Matilde Ragghianti
In many organisms, the specification of cell fate and the formation of embryonic axes depend on a proper distribution of maternal mRNAs during oogenesis. Asymmetrically localized determinants are required both for embryonic axes and germline determination in anuran amphibians. As a model system of these processes, we have used a species complex of the genus Pelophylax (Rana), characterized by a hybridogenetic reproduction that involves events of genome exclusion and endoreduplication during meiosis in both sexes. With the aim of characterizing the still largely unknown molecular events regulating Pelophylax gametogenesis, we have isolated in this animal model homologues of the deleted in AZoospermia-like (DAZl) and pumilio gene families (named RlDazl and RlPum1, respectively), which encode posttranscriptional regulators. Expression pattern analysis of these genes showed that RlDazl is exclusively expressed in gonadal tissues, whereas RlPum1 is expressed in both somatic tissues and gonads. In situ hybridization carried out on gonads revealed that the two transcripts were asymmetrically localized along the animal–vegetal (A–V) axis of oocytes. In particular, the RlDazl transcript progressively collected to the vegetal pole during oogenesis, whereas the RlPum1 mRNA was preferentially enriched at the animal hemisphere. In adult testes, RlDazl and RlPum1 were expressed in specific phases of spermatogenetic divisions as shown by immunostaining with anti-H3 phosphohistone antibody. Our results indicate that RlDazl and RlPum1 represent two early indicators of oocyte polarity in this hybridogenetic vertebrate model. Additionally, RlDazl share with vertebrate DAZ- like genes a germ cell-specific expression pattern. J. Exp. Zool. (Mol. Dev. Evol.) 316:330–338, 2011. © 2011 Wiley-Liss, Inc.
Volume 316B, Issue 5, pages 330–338, 15 July 2011
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20 giugno 2011
TRPV4 mediates tumor-derived endothelial cell migration via arachidonic acid-activated actin remodeling
Fiorio Pla Alessandra, Ong Hwei.Ling, Cheng K.T., Brossa Alessia, Benedetta Bussolati, Lockwich Timothy, Paria Biman, Munaron Luca and Ambudkar Indu S.
Changes in intracellular calcium [Ca(2+)](i) levels control critical cytosolic and nuclear events that are involved in the initiation and progression of tumor angiogenesis in endothelial cells (ECs). Therefore, the mechanism(s) involved in agonist-induced Ca(2+)(i) signaling is a potentially important molecular target for controlling angiogenesis and tumor growth. In this study we report that TRPV4, belonging to the TRP family of channels and activated by second messenger arachidonic acid (AA), is a key player in tumor angiogenesis in vitro. Together, the data presented herein demonstrate that: (1) TRPV4 is differentially expressed in tumor-derived versus 'normal' EC; (2) TRPV4 has a critical role in the migration of tumor-derived but not 'normal' EC migration; and (3) AA induces actin remodeling in BTEC, resulting in a corresponding increase of TRPV4 expression in the plasma membrane. We suggest that the latter is critical for migration of EC and thus in promoting angiogenesis and tumor growth.
Oncogene. 2011 Jun 20. doi: 10.1038/onc.2011.231. [Epub ahead of print]
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