Recent advances in regenerative medicine provide encouraging strategies to produce artificial skin substitutes. Gelatin scaffolds are successfully used as wound-dressing materials due to their superior properties, such as biocompatibility and the ability to mimic the extracellular matrix of the surrounding environment. In this study, five gelatin combination solutions were prepared and successfully electrospun using an electrospinning technique. After careful screening, the optimal concentration of the most promising combination was selected for further investigation. The obtained scaffolds were crosslinked with 25% glutaraldehyde vapor and characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. The incorporation of antibiotic agents such as ciprofloxacin hydrochloride and gentamicin sulfate into gelatin membranes improved the already existing antibacterial properties of antibiotic-free gelatin scaffolds against Pseudomonas aeruginosa and Staphylococcus aureus. Also, the outcomes from the in vivo model study revealed that skin regeneration was significantly accelerated with gelatin/ciprofloxacin scaffold treatment. Moreover, the gelatin nanofibers were found to strongly promote the neoangiogenic process in the in vivo chick embryo chorioallantoic membrane assay. Finally, the combination of gelatin’s extracellular matrix and antibacterial agents in the scaffold suggests its potential for effective wound-healing treatments, emphasizing the importance of gelatin scaffolds in tissue engineering.

Background/Objectives: In the Republic of Serbia, measles vaccination was first introduced in 1971, while combined vaccination (measles, mumps, rubella) was made mandatory in 1996 as part of the national vaccination program. Reported prevalence values for 2023 were <0.75 cases per 100K population for measles, 0.09 cases per 100K for mumps, and no cases of rubella. Methods: This cross-sectional study was performed in May, 2024 as part of the project “Herd Immunity to Vaccine-Preventable and Other Relevant Infections in the Belgradian Population.” It focused on assessing herd immunity to measles, mumps and rubella (MMR) among residents insofar as these remain a public concern despite the availability of vaccines. A total of 2533 subjects were distributed across nine age groups, covering those aged 1–70⁺ years and various professional groups residing in Belgrade. Participants were stratified by age and activity. Upon obtaining individual information by online questionnaire and receiving a signed statement of informed consent, blood samples were obtained for IgG antibody testing (ELISA) to determine MMR serological status. The results were compared to national and international immunization standards to evaluate herd immunity levels. Results: Our results indicate varying levels of immunity for each virus, with specific demographic groups showing different immunity levels. Total measles seroprevalence during this study was 74.7%, with significant variation across all age groups. While high seropositivity was observed in both children (90.7%) and elder age groups (98.4%), middle-aged individuals in the age group 30–49 years showed significantly lower IgG levels. Between 2021 and 2023, there were no registered cases of rubella detected in Serbia, which indicates a high level of immunity. This was confirmed here with consistently high IgG levels across all age groups, with an average seropositivity of 94.8%. Average mumps seropositivity across all age groups was 85.1%. The lowest value was in the young child (1–5 years) age group (76.1%); the highest was in the elderly group (92.6%). Conclusions: The current findings suggest that the Belgradian population has strong overall immunity to MMR, yet with some concerns regarding measles immunity in middle-aged adults, suggesting a potential need for catch-up vaccinations. While rubella status indicates strong herd immunity and minimal risk of outbreaks, mumps immunity in some groups (children, middle-aged adults) is below the protective threshold. While it is still sufficient to prevent widespread transmission, it should be closely observed. To our knowledge, this study is the first of its kind to provide data about MMR seroprevalence in Belgrade. Findings indicate the need for constant surveillance and revaccination of vulnerable/seronegative groups.

Finding and characterizing new bacterial strains, including probiotic strains, is a crucial task in today’s world to expand the genetic data pool and identify new genes. In this study, we investigated the gut microbiota of one industrial species, Cyprinus carpio, and identified representatives of various microbial genera, including Citrobacter, Serratia, Bacillus, Enterococcus, and Kocuria. Notably, we discovered two strains of Hafnia with potentially probiotic properties. We conducted next-generation sequencing (NGS) of these strains, described their antibiotic resistance and antibacterial activity, and compared them with other representatives of the Hafnia genus. These strains, characterized by rapid growth, the presence of the ClpB heat shock protein gene, and genes associated with microplastic degradation, provide a promising basis for further research, including studies on their potential application in plastic biodegradation.

Fluorescently labeled lectins are useful tools for in vivo and in vitro studies of the structure and function of tissues and various pathogens such as viruses, bacteria, and fungi. For the evaluation of high-mannose glycans present on various glycoproteins, a three-dimensional (3D) model of the chimera was designed from the crystal structures of recombinant banana lectin (BanLec, Protein Data Bank entry (PDB): 5EXG) and an enhanced green fluorescent protein (eGFP, PDB 4EUL) by applying molecular modeling and molecular mechanics and expressed in Escherichia coli. BanLec-eGFP, produced as a soluble cytosolic protein of about 42 kDa, revealed β-sheets (41%) as the predominant secondary structures, with the emission peak maximum detected at 509 nm (excitation wavelength 488 nm). More than 65% of the primary structure was confirmed by mass spectrometry. Competitive BanLec-eGFP binding to high mannose glycans of the influenza vaccine (Vaxigrip^®) was shown in a fluorescence-linked lectin sorbent assay (FLLSA) with monosaccharides (mannose and glucose) and wild type BanLec and H84T BanLec mutant. BanLec-eGFP exhibited binding to mannose residues on different strains of Salmonella in flow cytometry, with especially pronounced binding to a Salmonella Typhi clinical isolate. BanLec-eGFP can be a useful tool for screening high-mannose glycosylation sites on different microorganisms.

Notwithstanding prevalence gaps in micronutrients supporting immune functions, the significance of their deficits/supplementation for the efficacy of vaccines is underinvestigated. Thus, the influence of supplementation combining vitamins C and D, zinc, selenium, manganese, and N-acetyl cysteine on immune correlates/surrogates of protection conferred by a quadrivalent influenza vaccine (QIV) in mice was investigated. The supplementation starting 5 days before the first of two QIV injections given 28 days apart increased the serum titres of total and neutralizing IgG against each of four influenza strains from QIV. Accordingly, the frequencies of germinal center B cells, follicular CD4+ T helper (Th) cells, and IL-21-producing Th cells increased in secondary lymphoid organs (SLOs). Additionally, the supplementation improved already increased IgG response to the second QIV injection by augmenting not only neutralizing antibody production, but also IgG2a response, which is important for virus clearance, through favoring Th1 differentiation as indicated by Th1 (IFN-γ)/Th2 (IL-4) signature cytokine level ratio upon QIV restimulation in SLO cell cultures. This most likely partly reflected antioxidant action of the supplement as indicated by splenic redox status analyses. Thus, the study provides a solid scientific background for further research aimed at repurposing the use of this safe and inexpensive micronutrient combination to improve response to the influenza vaccine.

Background/Objectives: In the Republic of Serbia, anti-measles vaccination was first introduced in 1971, while combined vaccination (measles, mumps, rubella) was made mandatory in 1996 as part of the national vaccination program. Reported prevalence values for 2023 were: < 0.75 cases per 100K population for measles; 0.09 cases per 100K for mumps; and no cases of rubella. Methods: This cross-sectional study was performed in May, 2024 as part of the project "Herd Immunity to Vaccine-Preventable and Other Relevant Infections in the Belgradian Population." It focused on assessing herd immunity to measles, mumps and rubella (MMR) among residents, insofar as these remain a public concern despite the availability of vaccines. A total of 2,533 subjects were distributed across nine age groups, covering those aged 1-70+ years and various professional groups, residing in Belgrade. Participants were stratified by age and activity. Upon obtaining individual information by online questionnaire, and receiving a signed statement of in-formed consent, blood samples were obtained for IgG antibody testing (ELISA) to de-termine MMR serological status. The results were compared to national and interna-tional immunization standards to evaluate herd immunity levels. Results: Our results indicate varying levels of immunity for each virus, with specific demographic groups showing different immunity levels. Total measles seroprevalence during this study was 74.7%, with significant variation across all age groups. While high seropositivity was observed in both children (90.7%) and elder age groups (98.4%), middle-aged individuals in the age group 30-49 years showed significantly lower IgG levels. Between 2021 and 2023, there were no registered cases of rubella detected in Serbia, which indicates a high level of immunity. This was confirmed here with consistently high IgG levels across all age groups, with an average seropositivity of 94.8%. Average mumps seropositivity across all age groups was 85.1%. The lowest value was in the young child (1-5 years) age group (76.1%); the highest was in the elderly group (92.6%). Conclusions: The current findings suggest that the Belgradian population has strong overall immunity to MMR, yet with some concerns regarding measles immunity in middle-aged adults, suggesting a potential need for catch-up vaccinations. While rubella status indicates strong herd immunity and minimal risk of outbreaks, mumps immunity in some groups (children, middle-aged adults) is below the protective threshold. While it is still sufficient to pre-vent widespread transmission, it should be closely observed. To our knowledge, this study is the first of its kind to provide data about MMR seroprevalence in Belgrade. Findings indicate the need for constant surveillance and revaccination of vulnera-ble/seronegative groups.