Perception and memories in the fly brain

The brain is an extremely complex organ that controls thoughts, memories, motor skills and every process that is required to maintain our body alive and healthy. Although this is common knowledge, the mechanisms by which the brain performs these tasks are currently not fully understood. In this thesis, I focused on how sensory information is represented in higher brain regions, and how these representations are used to create and consolidate memories related to them. Precisely, using Drosophila melanogaster as a model, I investigated the circuitry of the mushroom body calyx, the input region of a neuropil involved in stimuli discrimination and memory formation in the fly brain. In the calyx, olfactory projection neurons synapse onto mushroom body intrinsic cells, the Kenyon cells, via synaptic complexes known as microglomeruli. Each microglomerulus is a microcircuit of his own, constituted by a central projection neuron presynaptic bouton surrounded by several dendritic endings of different Kenyon cells. This structural organization is believed to facilitate stimuli discrimination by transforming highly overlapping representations at the level of the projection neurons into sparse, decorrelated responses at the Kenyon cells one. Moreover, structural changes at the microglomerular level following associative memory formation have been reported in insect brains over the years. Nevertheless, the exact processes underlying such phenomena have not been described yet. Here, I show that memory consolidation induces structural plasticity in a stimulus-specific way in the calyx. Specifically, I found that the microglomeruli involved in the representation of the stimulus presented in the behavioural task increased in number after long-term memory formation. This increase in microglomeruli was protein synthesis dependent and strictly linked to the consolidation of the memory, as control flies and mutants unable to consolidate memories did not show structural changes within the same time frame. Furthermore, in this thesis I analyse the role of inhibitory synapses in microglomeruli of the calyx. Inhibition at the mushroom bodies is provided by the APL neuron, whose presence is required to maintain Kenyon cells odour responses sparse, hence facilitating odours discrimination in the fly. Here, I show that via inhibitory and reciprocal synapses targeting both projection neurons boutons and Kenyon cells dendrites, APL normalizes odour-evoked representations in microglomeruli of the calyx. In particular, I observed that APL inhibition scaled with the inputs strength and localized to the regions where those inputs were located within the calyx, leading to more homogenous responses in Kenyon cells dendrites. I confirmed this hypothesis by inhibiting output from the APL, which led to more variable activities in Kenyon cells dendrites. Altoghether, this thesis provides insights on how stimuli are processed, represented and used to create associative memories in the fly brain. As similar network organizations can be found in brains of other species including humans, I believe that the principles here described can be potentially applied to all brain regions sharing conformational features with the Drosophila mushroom body

Biometrics measurements in Red foxes (Vulpes vulpes) in the Picentini area. Discussion and conclusions

Techniques for assigning individual to age-classes and/or distinguish between sexes are necessary to understand population dynamics and behavioral interactions of Red foxes (Vulpes vulpes). Many studies have focused on separating juveniles from adults; age of captured live pups can be estimated from morphological changes, hind foot (HF) length, zygomatic (Z) width and body weight1. Methods that avoid capturing the animals would be particularly useful, but none is available. In this paper biometric differences between young adults and adults subjects and between sexes are investigated. Lower canine length (LCL), lower canine width (LCW), condilo-basal (CB) and scapular length resulted smaller than female adults, whereas male young adults had withers height, occipito-coccygeal (OC), ear length, and upper canine width (UCW) smaller than male adults. Almost all the parameters included in this study confirmed sexual dimorphism and some of the differences already present in young adults gained significance (from P<0.05 to P<0.01) in the adult foxes. In particular bodyweight, OC length, withers height, ear length, upper canine length and LCL, scapular and mandibular length, and inter-carnassial (IC) and Z width were significantly greater in male than in female adult foxes (P<0.01). Nasal-occipitalis (NO) length, total length, UCW and LCW, and upper dentition (UD) were significantly greater in male than in female adult foxes, as well (P<0.05). The low number of subjects included in each category, strictly due to hunting season, did not allow estimating an accurate range for the biometrics measurements performed and probably biased recordings, producing some contradictory results. Fox size varies geographically, thus mean adults measurements should be determined for each area in which they have to be applied1. HF method has been demonstrated to be an accurate method for assessing age of pups1; our data suggest that it might be as efficient in young adults, at least in female subjects. On the other hand, our results confirm the sexual dimorphism in the canine region to be higher than in the carnassial region (data not shown in our results)

The first report on detecting SARS-CoV-2 inside bacteria of the human gut microbiome: A case series on asymptomatic family members and a child with COVID-19

Many studies report the importance of using feces as source sample for detecting SARS-CoV-2 in patients with COVID-19 symptoms but who are negative to oropharyngeal/ nasopharyngeal tests. Here, we report the case of an asymptomatic child whose family members had negative results with the rapid antigen nasopharyngeal swab tests. The 21-month-old child presented with fever, diarrhea, bilateral conjunctivitis, and conspicuous lacrimation. In this study, analysis for the presence of SARS-CoV-2 in fecal samples by using Luminex technology allowed accurate detection of the presence of the viral RNA in the feces of the child and of all her relatives, which thus resulted to be positive but asymptomatic. It is the first time that SARS-CoV-2- is observed inside bacteria of the human gut microbiome and outside a matrix resembling extracellular bacterial lysates, in agreement with a bacteriophage mechanism with the images obtained by transmission electron microscopy (TEM), post-embedding immunogold, and by fluorescence microscope. In addition to the typical observations of respiratory symptoms, accurate evaluation of clinical gastrointestinal and neurological symptoms, combined with efficient highly sensitive molecular testing on feces, represent an efficient approach for detecting SARS-CoV-2, and for providing the correct therapy in challenging COVID-19 cases, like the one here reported

The first report on detecting SARS-CoV-2 inside human fecal-oral bacteria: A case series on asymptomatic family members and a child with COVID-19

Many studies report the importance of using feces as source sample for detecting SARS-CoV-2 in patients with COVID-19 symptoms but who are negative to oropharyngeal/ nasopharyngeal tests. Here, we report the case of an asymptomatic child whose family members had negative results with the rapid antigen nasopharyngeal swab tests. The 21-month-old child presented with fever, diarrhea, bilateral conjunctivitis, and conspicuous lacrimation. In this study, analysis for the presence of SARS-CoV-2 in fecal samples by using Luminex technology allowed accurate detection of the presence of the viral RNA in the feces of the child and of all her relatives, which thus resulted to be positive but asymptomatic. It is the first time that SARS-CoV-2- is observed inside human fecal-oral bacteria and outside a matrix resembling extracellular bacterial lysates, in agreement with a bacteriophage mechanism with the images obtained by transmission electron microscopy (TEM), post-embedding immunogold, and by fluorescence microscope. In addition to the typical observations of respiratory symptoms, accurate evaluation of clinical gastrointestinal and neurological symptoms, combined with efficient highly sensitive molecular testing on feces, represent an efficient approach for detecting SARS-CoV-2, and for providing the correct therapy in challenging COVID-19 cases, like the one here reported

The role of autophagy in resistance to targeted therapies

Autophagy is a self-degradative cellular process, involved in stress response such as starvation, hypoxia, and oxidative stress. This mechanism balances macro-molecule recycling to regulate cell homeostasis. In cancer, autophagy play a role in the development and progression, while several studies describe it as one of the key processes in drug resistance. In the last years, in addition to standard anti-cancer treatments such as chemotherapies and irradiation, targeted therapy became one of the most adopted strategies in clinical practices, mainly due to high specificity and reduced side effects. However, similar to standard treatments, drug resistance is the main challenge in most patients. Here, we summarize recent studies that investigated the role of autophagy in drug resistance after targeted therapy in different types of cancers. We highlight positive results and limitations of pre-clinical and clinical studies in which autophagy inhibitors are used in combination with targeted therapies. Refereed/Peer-reviewe

Synthesis of Chitosan-Coated Silver Nanoparticle Bioconjugates and Their Antimicrobial Activity against Multidrug-Resistant Bacteria

The increase in multidrug-resistant bacteria represents a true challenge in the pharmaceutical and biomedical fields. For this reason, research on the development of new potential antibacterial strategies is essential. Here, we describe the development of a green system for the synthesis of silver nanoparticles (AgNPs) bioconjugated with chitosan. We optimized a Prunus cerasus leaf extract as a source of silver and its conversion to chitosan–silver bioconjugates (CH-AgNPs). The AgNPs and CH-AgNPs were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), and zeta potential measurement (Z-potential). The cytotoxic activity of AgNPs and CH-AgNPs was assessed on Vero cells using the 3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide (MTT) cell proliferation assay. The antibacterial activity of AgNPs and CH-AgNPs synthesized using the green system was determined using the broth microdilution method. We evaluated the antimicrobial activity against standard ATCC and clinically isolated multisensitive (MS) and multidrug-resistant bacteria (MDR) Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Klebsiella pneumonia (K. pneumoniae), and Staphylococcus aureus (S. aureus), using minimum inhibitory concentration (MIC) assays and the broth dilution method. The results of the antibacterial studies demonstrate that the silver chitosan bioconjugates were able to inhibit the growth of MDR strains more effectively than silver nanoparticles alone, with reduced cellular toxicity. These nanoparticles were stable in solution and had wide-spectrum antibacterial activity. The synthesis of silver and silver chitosan bioconjugates from Prunus cerasus leaf extracts may therefore serve as a simple, ecofriendly, noncytotoxic, economical, reliable, and safe method to produce antimicrobial compounds with low cytotoxicity

Combined Raman and X-ray crystallography reveals multiple coordinations and quaternary states of fish hemoglobins

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Environmental Issues and Neurological Manifestations Associated with COVID-19 Pandemic: New Aspects of the Disease?

Coronavirus (SARS-CoV-2) emerged in China in December 2019 and rapidly caused a global health pandemic. Current evidence seems to suggest a possible link with ecosystem disequilibrium and even air pollution. The primary manifestations affect respiratory and circulatory systems, but neurological features are also being reported through case reports and case series. We summarize neurological symptoms and complications associated with COVID-19. We have searched for original articles published in PubMed/Medline, PubMed Central and Google Scholar using the following keywords: "COVID-19", "Coronavirus", "pandemic", "SARS-COV-2", "neurology", "neurological", "complications" and "manifestations". We found around 1000 publications addressing the issue of neurological conditions associated with COVID-19 infection. Amongst those, headache and dizziness are the most common reported symptoms followed by encephalopathy and delirium, while the most frequent complications are cerebrovascular accidents, Guillain-Barré syndrome, acute transverse myelitis, and acute encephalitis. Specific symptoms affecting the peripheral nervous system such as hyposmia and dysgeusia are the most common manifestations recorded in the selected studies. Interestingly, it was noted that these kinds of neurological symptoms might precede the typical features, such as fever and cough, in COVID patients. Neurological symptoms and complications associated with COVID-19 should be considered as a part of the clinical features of this novel global pandemic