Comparison of Irradiation and Wolbachia Based Approaches for Sterile-Male Strategies Targeting Aedes albopictus

The global expansion of Aedes albopictus together with the absence of vaccines for most of the arboviruses transmitted by this mosquito has stimulated the development of sterile-male strategies aiming at controlling disease transmission through the suppression of natural vector populations. In this context, two environmentally friendly control strategies, namely the Sterile Insect Technique (SIT) and the Wolbachia-based Incompatible Insect Technique (IIT) are currently being developed in several laboratories worldwide. So far however, there is a lack of comparative assessment of these strategies under the same controlled conditions. Here, we compared the mating capacities, i.e. insemination capacity, sterilization capacity and mating competitiveness of irradiated (35 Gy) and incompatible Ae. albopictus males at different ages and ratios under laboratory controlled conditions. Our data show that there was no significant difference in insemination capacity of irradiated and incompatible males, both male types showing lower capacities than untreated males at 1 day but recovering full capacity within 5 days following emergence. Regarding mating competitiveness trials, a global observed trend is that incompatible males tend to induce a lower hatching rate than irradiated males in cage controlled confrontations. More specifically, incompatible males were found more competitive than irradiated males in 5:1 ratio regardless of age, while irradiated males were only found more competitive than incompatible males in the 1:1 ratio at 10 days old. Overall, under the tested conditions, IIT seemed to be slightly more effective than SIT. However, considering that a single strategy will likely not be adapted to all environments, our data stimulates the need for comparative assessments of distinct strategies in up-scaled conditions in order to identify the most suitable and safe sterilizing technology to be implemented in a specific environmental setting and to identify the parameters requiring fine tuning in order to reach optimal release conditions.     

Impacts of urbanisation on biodiversity: the role of species mobility,degree of specialisation and spatial scale

Urbanisation has an important impact on biodiversity, mostly driving changes in species assemblages, through the replacement of specialist with generalist species, thus leading to biotic homogenisation. Mobility is also assumed to greatly affect species’ ability to cope in urban environments. Moreover, specialisation, mobility and their interaction are expected to greatly influence ecological processes such as metacommunity dynamics and assembly processes, and consequently the way and the spatial scale at which organisms respond to urbanisation. Here we investigate urbanisation impacts on distinct characteristics of species assemblages – namely specialisation degree in resource use, mobility and number of species, classified according to both characteristics and their combination – for vascular plants, butterflies and birds, across a range of spatial scales (from 1 × 1 km plots to 5 km‐radius buffers around them). We found that the degree of specialisation, mobility and their interaction, greatly influenced species’ responses to urbanisation, with highly mobile specialist species of all taxonomic groups being affected most. Two different patterns were found: for plants, urbanisation induced trait divergence by favouring highly mobile species with narrow habitat ranges. For birds and butterflies, however, it reduced the number of highly mobile specialist species, thus driving trait convergence. Mobile organisms, across and within taxonomic groups, tended to respond at larger spatial scales than those that are poorly mobile. These findings emphasize the need to take into consideration species’ ecological aspects, as well as a wide range of spatial scales when evaluating the impact of urbanisation on biodiversity. Our results also highlight the harmful impact of widespread urban expansion on organisms such as butterflies, especially highly mobile specialists, which were negatively affected by urban areas even at great distances.     

Telomeric DNA localization on dinoflagellate chromosomes: structural and evolutionary implications

Dinoflagellates are eukaryotic microalgae with distinct chromosomes throughout the cell cycle which lack histones and nucleosomes. The molecular organization of these chromosomes is still poorly understood. We have analysed the presence of telomeres in two evolutionarily distant and heterogeneous dinoflagellate species (Prorocentrum micans and Amphidinium carterae) by FISH with a probe containing the Arabidopsis consensus telomeric sequence. Telomere structures were identified at the chromosome ends of both species during interphase and mitosis and were frequently associated with the nuclear envelope. These results identify for the first time telomere structures in dinoflagellate chromosomes, which are formed in the absence of histones. The presence of telomeres supports the linear nature of dinoflagellate chromosomes.     

QuantiFERON TB Gold: a new method for latent tuberculosis infection

QuantiFERON-TB Gold obtained approval in 2003 by the Food and Drug Administration as a valid tool for the diagnosis of latent tuberculosis. In this report, we evaluated its potential use in the immunological diagnosis of Mycobacterium tuberculosis infections in different groups of subjects. Our data indicate that QuantiFERON-TB Gold is specific for identifying subjects who have come into contact with M. tuberculosis and its use alongside traditional diagnostic techniques may be an important instrument for controlling tuberculosis.     

Epithelial-myoepithelial carcinoma of the parotid gland,unusual malignancy radiologically simulating a benign lesion: case report

Background

Ultrasound (US), Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are widely used in the clinical diagnosis of parotid gland tumors and their efficacy in identifying benign lesions is well documented. However, problems arise when facing some malignant lesions. Only few cases of salivary gland low grade malignant tumors have been previously reported in the literature complete with the radiological features.

Case presentation

We here describe a case of epithelial-myoepithelial carcinoma (EMC) of the parotid gland, a low grade malignant tumor, with spread to an intraparotid lymph node and with CT and MRI findings mimicking a benign lesion.

Conclusion

All the images revealed sharply outlined profiles and a homogeneous enhancement of the nodule, suggesting a benign tumor and demonstrating that a radiological evaluation of the lesion alone may be unsatisfactory and misleading in the diagnosis of salivary gland tumours, especially in the case of low grade malignant tumors, such as EMC.

     

Crosstalk between Bak/Bax and mTOR signaling regulates radiation-induced autophagy

Bax and Bak, act as a gateway for caspase-mediated cell death. mTOR, an Akt downstream effector, plays a critical role in cell proliferation, growth and survival. The inhibition of mTOR induces autophagy, whereas apoptosis is a minor cell death mechanism in irradiated solid tumors. We explored possible alternative pathways for cell death induced by radiation in Bax/Bak-/- double knockout (DKO) MEF cells and wild-type cells, and we compared the cell survival: the Bax/Bak-/- cells were more radiosensitive than the wild-type cells. The irradiated cells displayed an increase in the pro-autophagic proteins ATG5-ATG12 and Beclin-1. These results are surprising in the fact that the inhibition of apoptosis resulted in increasing radiosensitivity; indicating that perhaps autophagy is the cornerstone in the cell radiation sensitivity regulation. Furthermore, irradiation upregulates autophagic programmed cell death in cells that are unable to undergo Bax/Bak-mediated apoptosis. We hypothesize the presence of a phosphatase-possibly PTEN, an Akt/mTOR negative regulator that can be inhibited by Bax/Bak. This fits with our hypothesis of Bax/Bak as a downregulator of autophagy. We are currently conducting experiments to explore the relationship between apoptosis and autophagy. Future directions in research include strategies targeting Bax/Bak in cancer xenografts and exploring novel radiosensitizers targeting autophagy pathways.     

Pyrrolomycins as antimicrobial agents. Microwave-assisted organic synthesis and insights into their antimicrobial mechanism of action

New compounds able to counteract staphylococcal biofilm formation are needed. In this study we investigate the mechanism of action of pyrrolomycins, whose potential as antimicrobial agents has been demonstrated. We performed a new efficient and easy method to use microwave organic synthesis suitable for obtaining pyrrolomycins in good yields and in suitable amount for their in vitro in-depth investigation. We evaluate the inhibitory activity towards Sortase A (SrtA), a transpeptidase responsible for covalent anchoring in Gram-positive peptidoglycan of many surface proteins involved in adhesion and in biofilm formation. All compounds show a good inhibitory activity toward SrtA, having IC₅₀ values ranging from 130 to 300?µM comparable to berberine hydrochloride. Of note compound 1d shows a good affinity in docking experiment to SrtA and exhibits the highest capability to interfere with biofilm formation of S. aureus showing an IC₅₀ of 3.4?nM. This compound is also effective in altering S. aureus murein hydrolase activity that is known to be responsible for degradation, turnover, and maturation of bacterial peptidoglycan and involved in the initial stages of S. aureus biofilm formation.     

Regulation of calpain activity in rat brain with altered Ca2+ homeostasis

Activation of calpain occurs as an early event in correlation with an increase in [Ca2+]i induced in rat brain upon treatment with a high salt diet for a prolonged period of time. The resulting sequential events have been monitored in the brain of normal and hypertensive rats of the Milan strain, diverging for a constitutive alteration in the level of [Ca2+]i found to be present in nerve cells of hypertensive animals. After 2 weeks of treatment, the levels of the plasma membrane Ca2+-ATPase and of native calpastatin are profoundly decreased. These degradative processes, more pronounced in the brain of hypertensive rats, are progressively and efficiently compensated in the brain of both rat strains by different incoming mechanisms. Along with calpastatin degradation, 15-kDa still-active inhibitory fragments are accumulated, capable of efficiently replacing the loss of native inhibitor molecules. A partial return to a more efficient control of Ca2+ homeostasis occurs in parallel, assured by an early increase in the expression of Ca2+-ATPase and of calpastatin, both producing, after 12 weeks of a high salt (sodium) diet, the restoration of almost original levels of the Ca2+ pump and of significant amounts of native inhibitor molecules. Thus, conservative calpastatin fragmentation, associated with an increased expression of Ca2+-ATPase and of the calpain natural inhibitor, has been demonstrated to occur in vivo in rat brain. This represents a sequential adaptive response capable of overcoming the effects of calpain activation induced by a moderate long term elevation of [Ca2+]i.