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Rafal Pokrowiecki,1–3 Jacek Wojnarowicz,4 Tomasz Zareba,2 Iwona Koltsov,4 Witold Lojkowski,4 Stefan Tyski,2,5 Agnieszka Mielczarek,6 Pawel Zawadzki1 1Department of Cranio-Maxillofacial Surgery, Oral Surgery and Implantology, Medical University of Warsaw, Warsaw, Poland; 2Department of Antibiotics and Microbiology, National Medicines Institute, Warsaw, Poland; 3Private Practice, Warsaw, Poland; 4Institute of High Pressure Physics, Polish Academy of Sciences, Warsaw, Poland; 5Department of Pharmaceutical Microbiology, Medical University of Warsaw, Warsaw, Poland; 6Department of Conservative Dentistry, Medical University of Warsaw, Warsaw, PolandCorrespondence: Agnieszka MielczarekDepartment of Conservative Dentistry, Medical University of Warsaw, Binieckiego 6, Warsaw 02-097, PolandTel +48 22 116 6446Fax +48 572 0154Email sekretariat.zachowawcza@wum.edu.plAim: The aims of this study were to investigate new nano-formulations based on ZnO and Ag nanoparticle (NP) compounds when used against clinical strains of oral gram-positive and gram-negative bacteria, and to examine the stability and behaviour of nano-formulation mixtures in saliva based on different compositions of Ag NPs, ZnO NPs and ZnO+x·Ag NPs. Methods: ZnO NPs with and without nanosilver were obtained by microwave solvothermal synthesis. Then, antibacterial activity was evaluated against bacteria isolated from human saliva. Behavior and nanoparticle solutions were evaluated in human saliva and control (artificial saliva and deionized water). Results were statistically compared. Results: The NP mixtures had an average size of 30±3 nm, while the commercial Ag NPs had an average size of 55±5 nm. The suspensions displayed differing antibacterial activities and kinetics of destabilisation processes, depending on NPs composition and fluid types.Conclusion: The present study showed that all NPs suspensions displayed significant destabilisation and high destabilisation over the 24 h of the analyses. The agglomeration processes of NPs in human saliva can be reversible.Keywords: nanomaterials, controlled drug release, nanoparticles, metal nanoparticles, bacteria

Rafal Pokrowiecki,1 Agnieszka Mielczarek,2 Tomasz Zareba,3 Stefan Tyski3,4 1Department of Head and Neck Surgery-Maxillofacial Surgery, Otolaryngology and Ophthalmology, Prof Stanislaw Popowski Voivoid Children Hospital, Olsztyn, 2Department of Conservative Dentistry, Medical University of Warsaw, 3Department of Antibiotics and Microbiology, National Medicines Institute, 4Department of Pharmaceutical Microbiology, Medical University of Warsaw, Warsaw, Poland Abstract: Peri-implant infective diseases (PIIDs) in oral implantology are commonly known as peri-implant mucositis (PIM) and periimplantitis (PI). While PIM is restricted to the peri-implant mucosa and is reversible, PI also affects implant-supporting bone and, therefore, is very difficult to eradicate. PIIDs in clinical outcome may resemble gingivitis and periodontitis, as they share similar risk factors. However, recent study in the field of proteomics and other molecular studies indicate that PIIDs exhibit significant differences when compared to periodontal diseases. This review aims to elucidate the current knowledge of PIIDs, their etiopathology and diversified microbiology as well as the role of molecular studies, which may be a key to personalized diagnostic and treatment protocols of peri-implant infections in the near future. Keywords: dental plaque, infection, titanium, microbiome, periimplantitis

Phytoplasmas are wall-less prokaryotes present as endocellular parasites in the plant phloem and phloem-feeding insects like leafhoppers (Cicadomorpha) and planthoppers (Fulgoromorpha). These unique bacteria, belonging to a monophyletic clade within the class Mollicutes, have the smallest known self-replicating genome. It consists of only 580-1350 kbp organized mainly in one circular chromosome and it lacks some genes previously considered to be essential for life. In some phytoplasmas, the existence of extrachromosomal elements has been confirmed. Every attempt to obtain axenic phytoplasma pure cultures has failed which impedes most aspects of their research. However, much progress has been done in the last two decades due to the application of various molecular biology-based methods. The most important tools for phytoplasma detection and classification are PCR and RFLP analyses of highly conserved 16S rRNA gene. Lately, other gene regions have been used for finer phytoplasma distinction in order to study their molecular variability and epidemiology. Even though the complete genome of one Candidatus Phytoplasma species is known, the combination of information on 16S rRNA gene and phytoplasma biological properties (plant host range, symptoms, insect vector species) remains to be the basis for the latest phytoplasma classification. Phytoplasmas cause hundreds of plant diseases worldwide and many of them affect economically important crops. On the other hand, insects that harbor and vector these prokaryotes in nature do not necessarily suffer such consequences. The occurrence of phytoplasmas causing grapevine yellows (GY) disease in Croatia was first recorded in 1997. Severely affected vines mostly show the presence of phytoplasmas from the ribosomal subgroup 16SrXII-A (stolbur or bois noir) while atypical and milder GY symptoms have been observed in Croatian indigenous vines that were infected with phytoplasmas of ribosomal subgroup 16SrI-B (aster yellows). By studying several genes of phytoplasmas found in Croatian vineyards, their insect vectors and alternative herbaceous hosts (vineyard weeds) we hope to decipher molecular and ecological factors discriminating this pathosystem from similar ones in Europe. Insight into the molecular epidemiology of GY should also enable devising more effective ways to control these phytoplasma-associated diseases.