Antibacterial activity of different natural honeys from Transylvania, Romania.

Honey is used in food industry and medicine due to its nutritive, therapeutic and dietetic qualities. The microbiological characteristics of 10 unpasteurized honey samples of known origin, collected from Transylvania beekeepers (Romania) were determined. The antibacterial activity of these types of honey against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella enteritidis, Salmonella anatum, Salmonella choleraesuis, Bacillus cereus, Bacillus subtilis subsp. spizizenii and Listeria monocytogenes strains was studied. The most sensitive to the antibacterial activity were the two staphylococus strains (the largest diameter of inhibition zone was 18 mm) and B. subtilis strains (13.5 mm). The strains of B. cereus, E. coli, L. monocytogenes and Salmonella spp. were found to present resistance to some of the honey samples. Manna, sunflower and polyfloral honeys presented high antibacterial activity while acacia and linden honeys had a lower activity in terms of the number of sensible strains. Statistical analysis shows that the type of strains and the type of honey have influence on the diameter of inhibition.

Study on the Biodegradation Process of D-Mannose Glycopolymers in Liquid Media and Soil.

Polymers derived from natural raw materials have become of great interest due to their increased biodegradable features and possible biocompatibility. Our group has successfully synthesized and characterized polymers derived from D-mannose oligomer (M), 2-hydroxy propyl acrylate (HPA), and methacrylate (HPMA) in different weight ratios. Their biodegradation was studied in liquid media with pure Proteus mirabilis inoculum for the samples with the most sugar residue, and the results show that the methacrylate derivative M_HPMA1 lost about 50% of its weight during incubation. SEM/EDX techniques were employed to display the modifications of the samples during the biodegradation process. The glycopolymers were buried in garden soil, and the experiment proved that more than 40% of the weight of the M_HPA1 sample was lost during biodegradation, while the other samples encountered an average of about 32% weight loss. The biodegradation profile was fitted against linear and polynomial mathematical models, which enabled an estimate of about a year for the total degradation of the D-mannose glycopolymers sample in soil.

Applications of Romanian Propolis in Phyto-Inhibitory Activity and Antimicrobial Protection: A Comparative Study.

Propolis use in medicine, pharmaceutical, cosmetic, and food industries is well known. This study aimed to investigate propolis' phyto-inhibitory and antimicrobial potential. Nine propolis samples obtained from distinct Romanian regions and characterized in terms of physical-chemical parameters, phenols and flavonoid contents, and antioxidant properties were prepared as dry propolis and aqueous extracts. The phyto-inhibitory effect was comparatively tested on different cereals: hexaploid bread wheat (Triticum aestivum), maize (Zea mays L.), oats (Avena sativa L.), and barley (Hordeum vulgare L.), while their in vitro antimicrobial activity was evaluated against bacterial and fungal strains specific to cereals: Bacillus subtilis, B. cereus, Proteus mirabilis, Fusarium oxysporum, Penicillium chrysogenum, and Aspergillus niger. All propolis samples showed a phyto-inhibitory effect on the cereals, the most pronounced being corn and oats. Propolis powder samples displayed a lower phyto-inhibitory activity than propolis extracts. Also, all tested products showed inhibitory efficacy against both bacteria and fungi. Furthermore, principal component analysis showed differences between the samples' phyto-inhibitory and antimicrobial properties depending on the geographical origin. Positive correlations were found between the polyphenols, flavonoid content, and antioxidant activity, respectively. These data support propolis' phyto-pharmaceutical potential related to its use in plant crop management as an alternative in ecological agriculture.

Phyto-Inhibitory and Antimicrobial Activity of Brown Propolis from Romania.

The objective of this paper was to study the phyto-inhibitory and antimicrobial activity of brown propolis collected from the counties of four regions in Romania. The main physico-chemical and functional properties of 16 samples of propolis from different landforms of geographical regions were determined. Their antimicrobial activities were established against 5 bacterial strains (Pseudomonas fluorescens, Bacillus subtilis, Bacillus cereus, Escherichia coli, and Proteus mirabilis) and 5 fungal strains (Alternaria alternata, Cladosporium cladosporioides, Fusarium oxysporum, Mucor racemosus, and Aspergillus niger). Simultaneously, the phyto-inhibitory effect of propolis samples on different cereals was highlighted: hexaploid bread wheat (Triticum aestivum), maize (Zea mays L.), oats (Avena sativa L.), and barley (Hordeum vulgare L.). Correlations between the antioxidant activity and total flavonoid and phenol content of the propolis samples were identified, respectively, and the statistical analysis highlighted that the diameter of the inhibition zone was influenced by the strain type (bacterial and fungal) and the geographical regions of propolis. Principal component analysis (PCA) indicated that out of seven principal components, only two exhibited > 0.5. Pearson's correlation coefficient showed a low and moderate positive linear relationship between the diameter of the inhibition zone and the flavonoid and phenol concentration of the propolis samples.

The Influence of HLA Alleles on the Affective Distress Profile.

(1) Background: Affective distress can be triggered by aggressive stimuli with an unfavorable role for the individual. Some of the factors that lead to the development and evolution of a mental disorder can be genetic. The aim of this study is to determine some correlations between the human leukocyte antigen (HLA) genes and the affective distress profile (PDA). (2) Methods: A psychological assessment and testing tool for anxiety was applied to 115 people. The low-resolution HLA alleles of class I (HLA-A, HLA-B, and HLA-C) and class II (HLA-DRB1 and HLA-DQB1) were identified by the PCR technique after DNA extraction from the blood. Depending on the PDA, the subjects were divided into two groups: a group with a low PDA and another one with a medium and high PDA. The IBM SPSS software was used to compare the frequency of HLA alleles between the two groups. (3) Results: The univariate analysis revealed a significant association of the HLA-A locus (A*01, A*30), HLA-B (B*08), and HLA-DRB1 (DRB1*11) with the low PDA group and of the HLA-A locus (A*32), HLA-B (B*52), and HLA-C (C*12) with the medium and high PDA group. (4) Conclusions: The present study highlighted potential associations between HLA alleles and anxiety disorders.

Qualitative Characterization and Antifungal Activity of Romanian Honey and Propolis.

The purpose of this study was to review the physicochemical characterization of Romanian honey and propolis and their antifungal effect on different strains. As an indicator of environmental pollution, lead exceeded the allowed limits in two study areas. The relationship between the acidity and electrical conductivity of polyfloral honey and the antioxidant activity with the total content of phenolics and flavonoids was investigated. The antifungal activity of 13 polyfloral honey and propolis samples from North-West and Central Romania and 12 samples from Alba County was investigated against six fungal strains: Aspergillus niger, Aspergillus flavus, Candida albicans, Penicillium chrysogenum, Rhizopus stolonifer, Fusarium oxysporum. All honey and propolis samples exhibited an antifungal effect. The most sensitive strains were P. chrysogenum and R. stolonifer for honey and P. chrysogenum and F. oxisporumn for propolis. A two-way analysis of variance was used to evaluate the correlations between the diameter of the inhibition zones for the strains and the propolis extracts. Statistical analysis demonstrated that the diameter of the inhibition zone was influenced by the strain type and the geographical origin of honey and propolis. Pearson's correlation coefficient shows a significant positive linear relationship between the diameter of the inhibition zone and the flavonoid and phenol concentration of honey and propolis, respectively.

An Empirical Model for Predicting Biodegradation Profiles of Glycopolymers.

Pollution caused by plastic materials has a great impact on the environment. The biodegradation process is a good treatment solution for common polymers and biodegradation susceptible ones. The present work introduces new insight into the biodegradation process from a mathematical point of view, as it envisions a new empirical model for this complex process. The model is an exponential function with two different time constants and a time delay, which follows the weight loss profile of the polymer during the biodegradation process. Moreover, this function can be generated as the output variable of a dynamic exogenous system described through state equations. The newly developed models displayed a good fit against the experimental data, as shown by statistical indicators. In addition, the new empirical model was compared to kinetics models available in the literature and the correlation coefficients were closest to 1 for the new empirical model in all discussed cases. The mathematical operations were performed in the MATLAB Simulink environment.

Assessing the microbiological contamination along with environmental factors of old books in the 1490-founded Bistrița Monastery, Romania.

Microbial contamination and damaging effects due to environmental factors (temperature, humidity) of old books is an extremely important issue in the heritage preserving field, being a great threat to this unique cultural and literary treasure. This paper analysed the indoor environmental conditions, the microbiological characteristics of the air and the condition itself of 27 clerical books (from eighteenth to nineteenth centuries), randomly chosen from the library of Bistrița Monastery, Romania. The analysis revealed that most of the books were contaminated and damaged by moulds and yeasts. The statistical analysis (chi-square test) shows that the incidence of mould species was not coincidental. The most common isolated fungi discovered on old books were Penicillium spp. (40.7%), Cladosporium spp. (33.3%) and Fusarium spp. (29.6%). Fungal contamination was observed in 17 books. Microbiota air tests have shown possible contamination by air flow. Often, the measured temperature/humidity values are not in line with the requirements of the legislation in force, especially during the cold seasons, the average minimum temperature varying from 3 to 6 °C to an average maximum temperature of 22-25 °C; the values of relative humidity were between 27 and 77%. In terms of storage conditions, the recorded values of temperature and humidity are extremely harmful to the stored documents. Therefore, these indoor environmental conditions have to be improved, in order to reduce/eliminate potential sources of fungal contamination and to achieve optimal environmental preserving conditions.

Biodegradation Pattern of Glycopolymer Based on D-Mannose Oligomer and Hydroxypropyl Acrylate.

Glycopolymers are polymers with sugar moieties which display biodegradable and/or biocompatible character. They have emerged as an environmentally-friendly solution to classical synthetic polymers and have attracted significant research interest in the past years. Herein, we present the synthesis of a D-mannose based glycopolymer with biodegradable features. The glycopolymer was synthesized by radical copolymerization between a D-mannose oligomer bearing polymerizable double bonds and 2-hydroxypropyl acrylate, in a weight ratio of 1:2. The copolymerization kinetics was investigated by differential scanning calorimetry (DSC) and the activation energy of the process was comparatively assessed by Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods. The obtained glycopolymer displayed good thermal behavior, fact proven by thermogravimetrical (TG) analysis and it was submitted to biodegradation inside a bioreactor fed with water from the Bega River as the source of microbial inoculum. The glycopolymer sample degraded by approximately 60% in just 23 days. The biodegradation pattern of the glycopolymer was successfully fitted against a modified sigmoidal exponential function. The kinetic model coefficients and its accuracy were calculated using Matlab and the correlation coefficient is more than promising. The changes inside glycopolymer structure after biodegradation were studied using TG and FTIR analyses, which revealed that the sugar moiety is firstly attacked by the microbial consortia as nutrient source for proliferation.

Comparative study on factors affecting anaerobic digestion of agricultural vegetal residues.

BACKGROUND: Presently, different studies are conducted related to the topic of biomass potential to generate through anaerobic fermentation process alternative fuels supposed to support the existing fossil fuel resources, which are more and more needed, in quantity, but also in quality of so called green energy. The present study focuses on depicting an optional way of capitalizing agricultural biomass residues using anaerobic fermentation in order to obtain biogas with satisfactory characteristics.. The research is based on wheat bran and a mix of damaged ground grains substrates for biogas production. RESULTS: The information and conclusions delivered offer results covering the general characteristics of biomass used , the process parameters with direct impact over the biogas production (temperature regime, pH values) and the daily biogas production for each batch relative to the used material. CONCLUSIONS: All conclusions are based on processing of monitoring process results , with accent on temperature and pH influence on the daily biogas production for the two batches. The main conclusion underlines the fact that the mixture batch produces a larger quantity of biogas, using approximately the same process conditions and input, in comparison to alone analyzed probes, indicating thus a higher potential for the biogas production than the wheat bran substrate.Adrian Eugen Cioabla, Ioana Ionel, Gabriela-Alina Dumitrel and Francisc Popescu contributed equally to this work.