In Silico Predicted Antifungal Peptides: In Vitro and In Vivo Anti-Candida Activity

It has been previously demonstrated that synthetic antibody-derived peptides could exert a significant activity in vitro, ex vivo, and/or in vivo against microorganisms and viruses, as well as immunomodulatory effects through the activation of immune cells. Based on the sequence of previously described antibody-derived peptides with recognized antifungal activity, an in silico analysis was conducted to identify novel antifungal candidates. The present study analyzed the candidacidal and structural properties of in silico designed peptides (ISDPs) derived by amino acid substitutions of the parent peptide KKVTMTCSAS. ISDPs proved to be more active in vitro than the parent peptide and all proved to be therapeutic in Galleria mellonella candidal infection, without showing toxic effects on mammalian cells. ISDPs were studied by circular dichroism spectroscopy, demonstrating different structural organization. These results allowed to validate a consensus sequence for the parent peptide KKVTMTCSAS that may be useful in the development of novel antimicrobial molecules

Chimeric symbionts expressing a Wolbachia protein stimulate mosquito immunity and inhibit filarial parasite development

Wolbachia can reduce the capability of mosquitoes to transmit infectious diseases to humans and is currently exploited in campaigns for the control of arboviruses, like dengue and Zika. Under the assumption that Wolbachia-mediated activation of insect immunity plays a role in the reduction of mosquito vectorial capacity, we focused our attention on the Wolbachia surface protein (WSP), a potential inductor of innate immunity. We hypothesized that the heterologous expression of this protein in gut- and tissue-associated symbionts may reduce parasite transmission. We thus engineered the mosquito bacterial symbiont Asaia to express WSP (AsaiaWSP). AsaiaWSP induced activation of the host immune response in Aedes aegypti and Anopheles stephensi mosquitoes, and inhibited the development of the heartworm parasite Dirofilaria immitis in Ae. aegypti. These results consolidate previous evidence on the immune-stimulating property of WSP and make AsaiaWSP worth of further investigations as a potential tool for the control of mosquito-borne diseases

Studies on the immunization against aflatoxins

Aflatossine (AF), metaboliti secondari tossici prodotti principalmente da ceppi dei funghi ubiquitari Aspergillus flavus e A. parasiticus, sono le più importanti micotossine di interesse medico (AFB1, AFB2, AFG1, AFG2). In seguito all’ingestione di alimenti contaminati, AFB1 e AFB2, in particolare, sono in parte assorbite e trasportate al fegato dove vengono convertite nei rispettivi metaboliti idrossilati AFM1 ed AFM2. Attraverso il torrente circolatorio, AFM1 e AFM2 possono raggiungere altri organi e tessuti ed essere escrete attraverso la via biliare, urinaria o mammaria (processo di carry-over). AFB1, la forma prevalente tra le AF, e AFM1 sono state classificate dall’ International Agency for Research on Cancer (IARC) come cancerogeni di gruppo 1 e di gruppo 2B, rispettivamente, per l’uomo. Al fine di ridurre il rischio di esposizione per l’uomo e gli animali, i livelli massimi di AF tollerati in alimenti e mangimi sono stati variamente regolamentati in molti paesi. In questo studio, è stato verificato il potenziale vaccinale di AFB1-1(O-carbossimetil) ossima (AFB1-ox), chimicamente derivata da AFB1, coniugata ad emocianina (KLH), per la prevenzione del carry-over in vacche da latte intossicate con AFB1. Comparativamente a AFB1, AFB1-ox è stata dimostrata atossica e non mutagena in vitro nei confronti di cellule di epatocarcinoma umano e ceppi di Salmonella typhimurium, rispettivamente, e definita Anaflatossina B1 (AnAFB1). In seguito ad immunizzazione sistemica di vacche da latte con il coniugato AnAFB1-KLH, è stata rilevata l’induzione di anticorpi (IgG) sierici specifici per AFB1, presentanti reattività crociata decrescente con AFG1, AFB2 e AFG2, in grado di prevenire l’escrezione di AFM1 nel latte di vacche sottoposte a ripetuti cicli di ingestione di mangime contaminato da quantità note di AFB1. La vaccinazione di lattifere con AnAFB1-KLH potrebbe rappresentare la prova di concetto per la soluzione del problema aflatossicosi M1 da latte e prodotti derivati, quali formaggi e yogurt, nell’uomo.Aflatoxins (AF), toxic secondary metabolites mainly produced by strains of Aspergillus flavus and A. parasiticus, represent the most important mycotoxins of medical interest (AFB1, AFB2, AFG1, AFG2). Once ingested, AFB1 and AFB2, in particular, are partially adsorbed and transported to the liver where they are metabolized into the hydroxy derivates AFM1 and AFM2 which, through the bloodstream, may reach other tissues and organs and be excreted, via bile, urinary and mammary pathways (carry-over process). AFB1, the most prevalent and toxic among AF, and AFM1 have been included by the International Agency for Research on Cancer (IARC) in group 1 and 2B human carcinogens, respectively. To reduce human and animal exposure, AF maximum levels in foods and feeds have been variously regulated in many countries. In this study, the vaccinal potential of the AFB1 derivate AFB1-1(O-carboxymethyl) oxime (AFB1-ox) conjugated to keyhole limpet hemocyanin (KLH) for carry-over prevention in dairy cattles intoxycated with AFB1 is reported. In comparison with AFB1, AFB1-ox has proven to be nontoxic in vitro to human hepatocarcinomas cells and devoid of mutagenic activity in Salmonella typhimurium tester strains, being therefore defined as anaflatoxin B1 (AnAFB1). AnAFB1-KLH proved to be immunogenic in cows following systemic administration, inducing specific anti-AFB1 IgG serum antibodies decreasingly cross reacting with AFG1, AFB2 and AFG2. The elicited anti-AF Abs were able to overcome the excretion of AFM1 into the milk of cattles repeatedly fed with determined amounts of AFB1. Vaccination of dairy cattle with AnAFB1-KLH may represent the prove of concept for the solution of the public hazard constituted by milk and milk products, such as cheese an yoghurt, contaminated with AFM1

AFM1 in Milk: Physical, Biological, and Prophylactic Methods to Mitigate Contamination

Aflatoxins (AFs) are toxic, carcinogenic, immunosuppressive secondary metabolites produced by some Aspergillus species which colonize crops, including many dietary staple foods and feed components. AFB1 is the prevalent and most toxic among AFs. In the liver, it is biotransformed into AFM1, which is then excreted into the milk of lactating mammals, including dairy animals. AFM1 has been shown to be cause of both acute and chronic toxicoses. The presence of AFM1 in milk and dairy products represents a worldwide concern since even small amounts of this metabolite may be of importance as long-term exposure is concerned. Contamination of milk may be mitigated either directly, decreasing the AFM1 content in contaminated milk, or indirectly, decreasing AFB1 contamination in the feed of dairy animals. Current strategies for AFM1 mitigation include good agricultural practices in pre-harvest and post-harvest management of feed crops (including storage) and physical or chemical decontamination of feed and milk. However, no single strategy offers a complete solution to the issue

Candidacidal Activity of a Novel Killer Toxin from Wickerhamomyces anomalus against Fluconazole-Susceptible and -Resistant Strains

The isolation and characterization from the sand fly Phlebotomus perniciosus of a Wickerhamomyces anomalus yeast strain (Wa1F1) displaying the killer phenotype was recently reported. In the present work, the killer toxin (KT) produced by Wa1F1 was purified and characterized, and its antimicrobial activity in vitro was investigated against fluconazole- susceptible and -resistant clinical isolates and laboratory strains of Candida albicans and C. glabrata displaying known mutations. Wa1F1-KT showed a differential killing ability against different mutant strains of the same species. The results may be useful for the design of therapeutic molecules based on Wa1F1-KT and the study of yeast resistance mechanisms

Oral and maxillofacial fungal infections

This book, written by world authorities in the field, is a comprehensive, up-to-date guide to the specialty of Oral Medicine, which is concerned with the diagnosis, prevention, and predominantly non-surgical management of medically related disorders and conditions affecting the oral and maxillofacial region. The pathophysiology, clinical presentation, diagnostic evaluation, and treatment of all relevant diseases and disorders are described with the aid of a wealth of clinical cases and illustrations that enable the reader to appreciate the diversity and potential complexity of Oral Medicine. In addition to the wide-ranging coverage of oral conditions, separate sections are devoted to bone and cutaneous pathology and to orofacial pain and its management, in addition to dental sleep medicine. The clinician who treats Oral Medicine patients will find this book to be an excellent aid to optimal management grounded in a sound knowledge of basic science and the dental and medical aspects of each disorder. In addition, it will serve as an outstanding textbook for undergraduate and postgraduate students

Anti-Infective Antibody-Derived Peptides Active against Endogenous and Exogenous Fungi

Mycoses still represent relevant opportunistic infections worldwide, although overshadowed in recent years by other severe and more widespread infections. Moreover, deep-seated mycoses are often accompanied by unacceptably high mortality rates. Etiologic agents include endogenous components of the mycobiota, Candida and Malassezia species above all, and exogenous species, both yeasts and filamentous fungi. Old and new fungal pathogens are increasingly characterized by resistance to the existing antifungal agents, making imperative the search for effective and safe new therapeutics. Among the candidate molecules proposed in recent decades, synthetic peptides derived from the complementarity determining and constant regions of diverse antibodies (Abs), as well as the translated products of Ab-encoding genes, have proved of considerable interest. Their anti-infective activities, regardless of the specificity and isotype of the originating Ab, will be briefly presented and discussed in the light of their different mechanisms of action. Intriguing suggestions on the possible function of Abs after their half-life will be presented, following the recent detection, in human serum, of an antimicrobial Ab-derived peptide. Overall, Abs could represent a source of biologically active, highly flexible peptides, devoid of detectable toxicity, which can be easily synthesized and manipulated to be used, alone or in association with already available drugs, for new anti-infective strategies

Anti-Infective Antibody-Derived Peptides Active against Endogenous and Exogenous Fungi

Mycoses still represent relevant opportunistic infections worldwide, although overshadowed in recent years by other severe and more widespread infections. Moreover, deep-seated mycoses are often accompanied by unacceptably high mortality rates. Etiologic agents include endogenous components of the mycobiota, Candida and Malassezia species above all, and exogenous species, both yeasts and filamentous fungi. Old and new fungal pathogens are increasingly characterized by resistance to the existing antifungal agents, making imperative the search for effective and safe new therapeutics. Among the candidate molecules proposed in recent decades, synthetic peptides derived from the complementarity determining and constant regions of diverse antibodies (Abs), as well as the translated products of Ab-encoding genes, have proved of considerable interest. Their anti-infective activities, regardless of the specificity and isotype of the originating Ab, will be briefly presented and discussed in the light of their different mechanisms of action. Intriguing suggestions on the possible function of Abs after their half-life will be presented, following the recent detection, in human serum, of an antimicrobial Ab-derived peptide. Overall, Abs could represent a source of biologically active, highly flexible peptides, devoid of detectable toxicity, which can be easily synthesized and manipulated to be used, alone or in association with already available drugs, for new anti-infective strategies