High Cell Surface Hydrophobicity Research Articles

Assessing Metschnikowia pulcherrima as a potential probiotic yeast for animal feed

Abstract In response to escalating antimicrobial resistance fuelled by their extensive use in livestock farming, this study explores alternative strategies in animal health management. We investigated the probiotic potential of Metschnikowia pulcherrima strains 4 × 3, DH5, ICS1 and QRI1 for their suitability in poultry environments. Our research demonstrated that previously discovered antimicrobial M. pulcherrima strains exhibit promising probiotic behaviours, including biofilm production, auto-aggregation, cell surface hydrophobicity, adhesion to Caco-2 cells, antioxidant capacity, and resilience to gastric stresses. Notable findings include DH5 exhibiting the highest biofilm formation, 4 × 3 and DH5 showing rapid auto-aggregation, 4 × 3 and ICS1 displaying high cell surface hydrophobicity, and all strains demonstrating considerable adherence to Caco-2 cells. 4 × 3 also exhibited exceptional bile tolerance, while ICS1 showed robust survival under simulated gastrointestinal conditions. These traits suggest M. pulcherrima’s capacity to colonise the poultry gastrointestinal tract, promote animal health, and support more sustainable livestock practices as a potential alternative to conventional antibiotics.

Anti-oral cancer properties of potential probiotic lactobacilli isolated from traditional milk, cheese, and yogurt

This study investigates the probiotic and anti-cancer effects of 21 isolated Lactobacillus strains from cheese, milk, and yogurt in Kermanshah, Iran, on oral cancer cell lines KB and OSCC. Four selected isolates (Y33, M45, C5, and C28) displayed good viability and resistance to specific antibiotics. Notably, strains C28 and Y33 exhibited the best results, showing susceptibility or semi-susceptibility to five antibiotics. Y33, with high cell surface hydrophobicity (62%), demonstrated significant anti-pathogenic activity, inhibiting the growth of tested pathogens and displaying strong adhesion to human intestinal Caco-2 cells (52%). Further assessments, including acridine orange/ethidium bromide staining and mRNA expression analysis, revealed four isolates (C5, C28, M45, and Y33) with promising probiotic properties. Particularly, Y33’s protein-based extract metabolites showed dose- and time-dependent inhibition of KB and OSCC cancer cell lines, inducing apoptosis without significant cytotoxic effects on normal cells. Y33 (Lactiplantibacillus plantarum) exhibited the strongest probiotic potential, surpassing conventional anti-cancer drugs, suggesting its therapeutic potential for preventing oral cancer cell proliferation and improving survival rates in oral cancer patients.

Assessment of the in-vitro probiotic efficacy and safety of Pediococcus pentosaceus L1 and Streptococcus thermophilus L3 isolated from Laban, a popular fermented milk product.

Probiotics are beneficial microorganisms, mostly lactic acid bacteria (LAB), that offer health benefits to the host when consumed in adequate amounts. This study assessed the probiotic efficacy and safety of LAB strains isolated from Laban, a traditional fermented milk product. Seven primarily selected Gram-positive, catalase-negative, non-spore-forming isolates were examined for their antimicrobial activity against the bacterial pathogens Bacillus cereus, Salmonella typhi, Staphylococcus aureus, and Vibrio cholera, and the fungal pathogen Candida albicans. Two isolates, identified as Pediococcus pentosaceus L1 and Streptococcus thermophilus L3, which showed antimicrobial activity against all pathogens, were further evaluated for their probiotic competence. The selected isolates demonstrated strong resistance to low pH, bile salts, and phenol, indicating their potential for gastric endurance. They also exhibited high cell surface hydrophobicity to various hydrocarbons, autoaggregation, and coaggregation properties, demonstrating strong adhesion abilities. In addition, both isolates showed strong antioxidant activity and were non-hemolytic. Although the isolates had some resistance to certain antibiotics, they were generally susceptible to commonly used antibiotics. The two LAB strains also exhibited promising technological properties, such as milk coagulation and exopolysaccharide production, indicating their potential to enhance the quality of dairy products. The results suggest that the LAB strains isolated from Laban have strong potential as probiotics, and due to their food origin, they are highly likely to exhibit maximal efficacy in food and pharmaceutical products for human consumption.

Determining probiotic properties and fermented milk production potential of Lactobacillus strains inhabiting traditional buffalo curd

Traditional buffalo curd is a rich source of wild-type lactic acid bacteria (LAB) having a broad range of probiotic characteristics. However, its application in the dairy industry is minimal. The current study aims to 1) determine probiotic properties (i.e., resistance to pH, bile, phenol, antibiotics, cell surface hydrophobicity, antibacterial activity, antifungal susceptibility, haemolytic and DNase activity) of Lactobacillus strains inhabiting back-slopped buffalo curd, 2) evaluate the characteristics of fermented milk produced using these isolated bacterial monocultures, by testing for the viability of LAB in fermented milk, changes in pH value, measurement of syneresis, texture profile analysis, high-performance liquid chromatography (HPLC), and Fourier-transform infrared spectroscopy (FTIR) analysis. Results indicated that, five bacterial strains belonging to L. delbrueckii subsp. indicus with substantial genotypic diversity within the strains, showed the best probiotic and milk fermentation properties. Furthermore, out of the isolates, L. delbrueckii subsp. indicus SUR_IN-55 showed a significantly (p < 0.05) higher survival rate at pH 3, 0.3% bile, 0.6% phenol, and high cell surface hydrophobicity. In addition, all five L. delbrueckii subsp. indicus strains demonstrated good antibacterial activity and antibiotic resistivity, with minimal differences across the strains. HPLC and FTIR analysis results showed 2.6% ± 0.02% of lactic acid production during the lactic acid fermentation of strain SUR_IN-55 with significantly (p < 0.05) lower syneresis, and higher viability with acceptable texture parameters compared to other monocultures. Overall findings verify that L. delbrueckii subsp. indicus strains SUR_IN-55, ANU_IN-91, and THS_IN-36 can be used as starter culture bacteria in the production of value-added fermented dairy products with probiotic characteristics.

The variations of native plasmids greatly affect the cell surface hydrophobicity of sphingomonads.

Microbial cell surface hydrophobicity (CSH) reflects nonspecific adhesion ability and affects various physiological processes, such as biofilm formation and pollutant biodegradation. Understanding the regulation mechanisms of CSH will contribute to illuminating microbial adaptation strategies and provide guidance for controlling CSH artificially to benefit humans. Sphingomonads, a common bacterial group with great xenobiotic-degrading ability, generally show higher CSH than typical Gram-negative bacteria, which plays a positive role in organic pollutant capture and cell colonization. This study verified that the variations of two native plasmids involved in synthesizing outer membrane proteins and polysaccharides greatly affected the CSH of sphingomonads. It is feasible to control their CSH by changing the plasmid copy number and sequences. Additionally, considering that plasmids are likely to evolve faster than chromosomes, the CSH of sphingomonads may evolve quickly to respond to environmental changes. Our results provide valuable insights into the CSH regulation and evolution of sphingomonads.

In vitro evaluation of probiotic properties of yeasts and lactic acid bacteria isolated from ersho samples collected from different parts of Ethiopia

ABSTRACT Ersho is an undefined starter culture used for Ethiopian injera production, and it is a good source of yeasts and lactic acid bacteria (LAB). However, few researchers have been done on the characterization of yeasts and LAB from ersho samples as a source of probiotics. The objective of the current work was to isolate and screen yeasts and LAB from ersho samples and in vitro characterization of their probiotic properties. An experimental research design was used. A total of 55 ersho samples were collected. Based on the ersho samples, 220 yeast colonies and 220 LAB colonies were isolated and purified. For the probiotic characterization, three yeasts (4A, 14D, 54A) and three LAB (1A, 13E, and 55A) were chosen. The isolates 4A, 14D, 54A, 1A, 13E, and 55A were identified as Saccharomyces cerevisiae KRSAN1, Saccharomyces cerevisiae JYC2577, Kazachstania humilis, Enterococcus lactis, Lactobacillus paracasei, and Lactobacillus species, respectively. All the isolates showed positive probiotic characteristics. They had very good acid resistance (percentage survival > 80%), high bile salt resistance (percentage survival > 140%), high cell surface hydrophobicity (>40%), high levels of auto-aggregation (>40%), variable co-aggregation with pathogens (ranged between 42% and 72%), variable antimicrobial activity (clear halo zone ranged from 4.0 to 31 mm), and variable antibiotic resistance responses. The results indicated that the ersho samples can be used as yeast and LAB sources for developing food and probiotic starter cultures.

Isolation, Evaluation, and In-Vitro Characterization of Lactobacillus Isolated from Traditional Fermented Food Finger Millet (Eleusine coracana) Batter for Their Probiotic Attributes

ABSTRACT This study aimed to evaluate and characterize lactic acid bacteria for their probiotic attributes from traditional fermented food, Finger millet batter, and to explore the ability of probiotic lactic acid bacteria to inhibit food borne pathogens. Among all 40 isolates, five bioactive isolates Lactiplantibacillus plantarum MYSRD57, Lacticaseibacillus paracasei MYSRD68, Lactiplantibacillus plantarum MYSDS3, Lactiplantibacillus plantarum MYSDS4 and Lactiplantibacillus plantarum MYSDVN3 with best probiotic attributes were selected and presented in this study. The antimicrobial efficacy of Lactobacillus and their cell free supernatant were effective in controlling pathogens all the foodborne pathogens in vitro. Furthermore, these strains exhibited important probiotic characteristics, such as antibiotics susceptibility, anti-hemolytic activity, tolerance to acidic pH, phenol, sodium chloride, 0.3% bile and survival ability at different temperatures. All the strains were also exhibited high auto-aggregation and cell surface hydrophobicity. Therefore, our findings demonstrated important probiotic features of lactic acid bacteria , while inhibiting multiple pathogens, suggesting possible applications of these potential probiotics strains.

Nanoscale delivery system for improving Bacillus subtilis probiotic viability: A promising safety-enhanced nanoemulsion

Bacillus subtilis is a bacterium with probiotic properties and health benefits, but its effectiveness can be compromised due to its susceptibility to environmental factors and stomach acid. Encapsulation safeguards the bacteria from harsh conditions and facilitates optimal therapeutic efficacy through controlled release in the gut. This study explores the development and efficacity of a nanoscale delivery system for B. subtilis probiotics nanoemulsion-based tocopherol using the binary emulsifier system (Tween 80: Gum Arabic 0.75:0.25 v/v). Key findings include a reduction of 1.9 log CFU.mL−1 for the B. subtilis nanoemulsion under simulated gastrointestinal conditions, compared to a decrease of 6.12 log CFU.mL− 1 for free cells. The encapsulated B. subtilis showcased high bacteriocin production reaching 2000 AU/mL during the stationary phase, as opposed to the average 1000 AU/mL in free B. subtilis cells. The nanoemulsion demonstrated resistance to various pH levels, retained antimicrobial activity, and exhibited high cell surface hydrophobicity along with DPPH elimination activity. The viability of encapsulated B. subtilis was significantly better under different storage conditions, maintaining a viable probiotic cell count of 7 Log CFU/mL up to 80 days. The probiotic strain showed varying susceptibility to antibiotics, indicating the potential for food safety concerns. Overall, the use of gum Arabic-based delivery system as prebiotics in the nanoemulsion formulation enhanced the performance of B. subtilis probiotics, suggesting a promising approach for the treatment of gastrointestinal disorders and for delivering viable and metabolically active probiotics to the intestine. However, further experiments are required to fully explore its potential.

Evaluation cell surface hydrophobicity of four potential probiotics Lactic acid bacteria's isolated from local dairy products

The purpose of this study was to investigate the cell surface hydrophobicity of four Lactic acid bacteria (LAB) strains isolated from various traditional and industry fermented yogurt and cheese sources based on the biochemical tests. The determining cell surface hydrophobicity is a critical step in selecting LAB strains with probiotic qualities and is one of the most essential elements regulating LAB's particular adherence to abiotic surfaces, as well as one of the most critical factors controlling LAB's absorption and destruction of hydrophobic organic matter. In current study, the four LAB strains had high cell surface hydrophobicity to the four separate hydrocarbon solvents xylene, hexadecane, chloroform, ethyl acetate determined via spectrophotometer at 450 nm. The highest hydrophobicity score was determined for LB3 for chloroform, n- hexadecane, ethyl acetate and xylene at 66.51, 38.23, 33.67 and 24.18% respectively. LB3 demonstrated promising cell surface characteristics, suggesting that it could be used as an indigenous probiotic

Probiotic, technological and health-related characteristics of lactobacilli isolated from breast milk.

Isolation and characterisation of lactobacilli from human milk and determination of their probiotic, technological and in vitro health-promoting properties with a view to their potential use in food fermentation. Seven lactobacilli isolates were obtained from human milk and identified as Lacticaseibacillus paracasei (isolates BM1-BM6) and Lactobacillus gasseri (BM7). The isolates were examined in vitro for their technological, probiotic and health-promoting potential. Overall, all isolates showed important technological properties based on the ability to grow in milk whey, a high to moderate acidification capacity and the absence of undesirable enzymatic activities. L. gasseri (BM7) differed from the L. paracasei isolates by the absence of several glycosidases and the inability to ferment lactose. Isolates L. paracasei BM3 and BM5 produced exopolysaccharides (EPS) from lactose. All isolates showed probiotic potential as they were tolerant to simulated gastrointestinal conditions, had high cell surface hydrophobicity, had not acquired resistance to relevant antibiotics and had no virulence characteristics. All L. paracasei showed high antimicrobial activity against various pathogenic bacteria and fungi, while L. gasseri showed a narrower spectrum of antimicrobial activity. All isolates showed health-promoting potential in vitro, as evidenced by high cholesterol-lowering activity, high ACE inhibitory activity and marked antioxidant activity. All strains showed excellent probiotic and technological properties for use in lactic ferments. Lactobacilli are an important part of the microbial population in human milk. A more detailed characterisation of these bacteria can contribute to the understanding of their functional and health importance for infants and to the selection of new probiotic strains for the dairy industry.

Phenotypic and genotypic characterization of multi-drug resistant, biofilm forming, human invasive strain of Salmonella Typhimurium SMC25 isolated from poultry meat in India

Emergence of highly virulent and multi-drug resistant (MDR) strains of Salmonella in food products significantly impacts public health and demands continuous monitoring for their presence in the food chain. The ability of Salmonella to form biofilms under harsh environmental conditions accompanied by MDR serotypes underscores an important food safety threat. This study aimed to isolate, identify and characterize MDR, biofilm-forming Salmonella from local Indian dairy and meat products (n = 60). All of the 24 isolates of Salmonella produced biofilm and were categorized as strong (16.6%), moderate (58.3%), and weak (25%) biofilm producers. Multiple antimicrobial resistance (MAR) index of all the Salmonella isolates was ≥0.2. The strongest biofilm forming poultry meat isolate, Salmonella SMC25 demonstrated intermediate to complete resistance to 14 of 22 different antibiotics tested. Epifluorescence microscopy showed that biofilm formation initiated as early as 4 h, reaching zenith within 96 h and much denser and robust biofilm is formed on rough stainless steel (SS316) surface compared to smooth glass surface. The results corroborated with increased temporal production of exopolysaccharides (EPS), high cell surface hydrophobicity and upregulation of marker genes vital to biofilm-formation in Salmonella. Significantly, SMC25 was found to adhere and invade mammalian cell lines Caco2 and HepG2, thus posing a serious food safety threat. This study is important in comprehending the prevalence of multidrug resistant, biofilm-forming, invasive strains of foodborne Salmonella in Indian food products and is important for effective risk assessment besides ensuring better food safety and public health.

Melanization of Candida auris Is Associated with Alteration of Extracellular pH.

Candida auris is a recently emerged global fungal pathogen, which causes life-threatening infections, often in healthcare settings. C. auris infections are worrisome because the fungus is often resistant to multiple antifungal drug classes. Furthermore, C. auris forms durable and difficult to remove biofilms. Due to the relatively recent, resilient, and resistant nature of C. auris, we investigated whether it produces the common fungal virulence factor melanin. Melanin is a black-brown pigment typically produced following enzymatic oxidation of aromatic precursors, which promotes fungal virulence through oxidative stress resistance, mammalian immune response evasion, and antifungal peptide and pharmaceutical inactivation. We found that certain strains of C. auris oxidized L-DOPA and catecholamines into melanin. Melanization occurred extracellularly in a process mediated by alkalinization of the extracellular environment, resulting in granule-like structures that adhere to the fungus’ external surface. C. auris had relatively high cell surface hydrophobicity, but there was no correlation between hydrophobicity and melanization. Melanin protected the fungus from oxidative damage, but we did not observe a protective role during infection of macrophages or Galleria mellonella larvae. In summary, C. auris alkalinizes the extracellular medium, which promotes the non-enzymatic oxidation of L-DOPA to melanin that attaches to its surface, thus illustrating a novel mechanism for fungal melanization.

Screening and Identification of Naphthalene-Degrading Bacteria from the Coastal Regions of Makran Sea

Makran Sea and its coastal areas are one of the richest marine ecosystems in the world. The primary purpose of this research was to study Naphthalene-degrading bacteria in some coastal areas of Makran Sea. Four coastal areas of Makran Sea were selected and marine samples were taken from each. Naphthalene-degrading bacteria were enriched in ONR medium in the shaker incubator for seven days with Naphthalene as the sole carbon source. This process was carried out in two separate passages. Some screening analyses were conducted for the selection of the best Naphthalene-degrading strains such as growth assay (OD600 nm), Naphthalene-degradation (GC), cell surface hydrophobicity (BATH), and emulsion production (E24). The predominant strain in Naphthalene-degradation was identified by molecular method. The results of this study showed that the quantity of bacteria present in different regions of Makran Sea varies. An example of this was the highest quantity of Naphthalene-degrading bacteria which were observed in Jask Port, however, the level of heterotrophic bacteria was the highest in Konark Station in comparison to other areas. In this research 65 Naphthalene-degrading bacteria were isolated from collected marine samples. Screening analysis confirmed that 9 strains were more efficient in Naphthalene-degradation and these strains were selected for further study. The best Naphthalene degrader isolate in this study was HS-2 strain, which according to molecular identification results belongs to Shewanella alga. This strain was an emulsifier producer (E24: 88%), and had high cell surface hydrophobicity (BATH: 36%) and was able to degrade Naphthalene in 3000 ppm concentration (70.8%). The results of this research confirmed that Makran marine ecosystem has effective bacteria in the degradation of Polycyclic Aromatic Compounds (PAH). By using these bacteria in the field, it is possible to reduce aromatic pollution in these coastal areas.

Multi-functional Potential of Five Lactic Acid Bacteria Strains Derived from Giant Panda (Ailuropoda melanoleuca).

The multi-functional properties of lactic acid bacteria (LAB) on host health have been a popular research topic. The aim of present study was to assess the multi-functional potential of five LAB strains isolated from giant panda. In this study, we analyzed five giant panda LAB strains (Weissella confuse WJ202003 (W3), WJ202009 (W9), WJ202021 (W21), BSP201703 (X3); Lactiplantibacillus plantarum BSGP201683 (G83)) and found that they exhibited rapid growth as well as strong acid production capacity. The five LAB strains possessed high cell surface hydrophobicity to the four tested solvents (xylene, hexadecane, chloroform, ethyl acetate; except strain W9), auto-aggregation ability, co-aggregation ability with three pathogens (Escherichia coli, Enterotoxigenic Escherichia coli, Salmonella), adhesion ability to Caco-2 cell line, and strongly biofilm formation ability, suggesting an adhesion property. As investigated for their antioxidative potential, all the strains showed good tolerance to H2O2, high scavenging ability against 1, 1-diphenyl-2-picrylhydrazyl (DPPH), and hydroxyl (OH-), and reduction ability. Furthermore, the five LAB strains could produce multiple probiotic substances, including exopolysaccharide (EPS), gamma-aminobutyric acid (GABA), bile salt hydrolase (BSH), cellulase (only strain G83), and protease (except strain X3), which was the first to report the production of EPS, GABA, BSH, cellulase, and protease in giant panda-derived LAB strain. These results demonstrated that strains W3, W9, W21, X3, and G83 had multi-functional potential and could be utilized as potential probiotics for giant panda.

A novel probiotic strain of Lactobacillus fermentum TIU19 isolated from Haria beer showing both in vitro antibacterial and antibiofilm properties upon two multi resistant uro-pathogen strains.

Probiotics with antimicrobial activity are gaining interest as a topic in the research field. Urinary tract infections (UTIs), acquired in the hospital or the community, are among the most prevalent infections. The emergence of multidrug resistance (MDR) uro-pathogens has made the current situation more critical in terms of global public health.To face this situation, in this study, Lactobacillus fermentum TIU19 (L. fermentum TIU19) was isolated and characterized as a new probiotic strain of the rice-based fermented beverage Haria. Subsequently, we also investigated its application as a biological agent that inhibits the growth of multidrug-resistant uro-pathogens, Escherichia coli, and Enterococcus faecalis. The results showed that, the isolated strain L. fermentum TIU19 was sensitive to all antibiotics tested except vancomycin and was devoid of virulence factors, such as haemolytic and gelatinase activities. Therefore, it may be considered safe for public health. It has many probiotic properties, such as survival in simulated gastrointestinal fluid, antioxidant activity, β-galactosidase producing ability, high cell surface hydrophobicity, adhesion ability to epithelial cells, and strong biofilm producer. The growth inhibitory and antibiofilm activities were shown against two uro-pathogens. All these results suggest that L. fermentum TIU19 can be explored as a potential probiotic with antagonistic activity against MDR uro-pathogenic E. coli and E. faecalis.

Probiotic and Antioxidant Properties of Lactic Acid Bacteria Isolated from Indigenous Fermented Tea Leaves (Miang) of North Thailand and Promising Application in Synbiotic Formulation

Miang, a traditional fermented tea from Northern Thailand, potentially hosts beneficial probiotic bacteria. A total of 133 isolates of lactic acid bacteria (LAB) isolated from Miang were evaluated for probiotic potential. Among them, 5 strains showed high tolerance to bile and acidic conditions and were selected for further evaluation. All selected strains showed inhibitory activity against human pathogens, including Bacillus cereus, Staphylococcus aureus, and Salmonella ser. Typhimurium. Nucleotide sequences analysis of the 16S rRNA gene revealed that 3 isolates were identified as Lactobacillus pentosus; the remaining were L. plantarum and Pediococcus pentosaceus, respectively. All 5 strains showed a high survival rate of more than 90% when exposed to simulated gastrointestinal conditions and were also susceptible to antibiotics such as erythromycin, tetracycline, and gentamycin, and resistant to vancomycin, streptomycin, and polymycin. In addition, the selected isolates exhibited different degrees of cell surface hydrophobicity (58.3–92.9%) and auto-aggregation (38.9–46.0%). The antioxidant activity reflected in DPPH scavenging activities of viable cells and their cell-free culture supernatants (CFCS) were also found in selected LAB isolates. Moreover, selected LAB isolates showed ability to grow on commercial prebiotics (GOS, FOS or XOS). The preliminary study of spray-drying using cyclodextrin as thermoprotectant suggested that all strains can be designed as a powdered formulation. L. pentosus A14-6 was the best strain, with high tolerance against simulated gastrointestinal conditions, high cell surface hydrophobicity, effective response to tested commercial oligosaccharides, especially XOS, and the highest cell antioxidant properties. L. pentosus A14-6 was therefore targeted for further applications in food and synbiotic applications.

Exploration of Strategies for the Enhanced Biodegradation of Low-Density Polyethylene (LDPE) by A Soil Bacterium Enterobacter Cloacae AKS7

In the context of sustainable bioremediation of Low-density polyethylene (LDPE), in this study, several strategies were explored to enhance the LDPE degradation by the bacterium Enterobacter cloacae AKS7. Initially, Mineral oil and Tween 80 were used to test whether they could modulate microbial colonization and polymer degradation by AKS7. Results indicated Mineral oil could increase microbial colonization and LDPE degradation whereas Tween 80 compromised the same. Since LDPE holds hydrophobic characteristics, the organism showing higher cell-surface hydrophobicity could adhere efficiently to the polymer. Thus, the organism AKS7 was grown in media with different concentrations of glucose and ammonium sulphate to exhibit differences in cell-surface hydrophobicity. We noticed that with increasing cell-surface hydrophobicity, the microbial colonization and LDPE degradation got enhanced considerably. The observations indicated that cell-surface hydrophobicity promoted microbial colonization to LDPE that increased the degree of biodegradation. Besides, LDPE films were photo-oxidized before microbial exposure which showed that AKS7 could degrade ultra-violet (UV) treated LDPE more proficiently compared to the UV-untreated polymer. Moreover, AKS7 could colonize more effectively to the UV-treated LDPE in contrast to the untreated LDPE. Furthermore, it was observed that UV exposure increased the carbonyl bond index of the polymer which got utilized by the organism efficiently thereby increasing the polymer degradation. Hence, the observations indicated that effective microbial colonization to UV-treated LDPE films exhibited a promising metabolic activity that could show an enhanced degradation of LDPE. Therefore, AKS7 warrants to be considered as a promising organism for enhanced degradation of LDPE.

Dynamic characteristics of microbial community and soluble microbial products in partial nitrification biofilm system developed from marine sediments treating high salinity wastewater

High salinity wastewater generally resulted in microorganism death and low treatment efficiency of nutrient in conventional activity sludge system. Marine sediments, containing a huge amount of natural salt-tolerant microorganisms, provide a feasible option for the rapid construction of halophilic biological treatment system. However, the dynamic of native microorganisms and the fate of soluble microbial products (SMP) in halophilic biofilm system developed from marine sediments needs to be further studied. In this study, a partial nitrification system was successfully established by inoculation of marine sediments in sequential batch biofilm reactor. Satisfactory chemical oxygen demand (COD) and NH4+-N removal efficiency (95% and 99%) and nitrite accumulation rate (NAR) (>90%) was achieved for treatment of synthetic seawater blackwater. High cell surface hydrophobicity (CSH) and proteins to polysaccharide ratio of extracellular polymeric substance (EPS) were beneficial to the initial biofilm formation. High-throughput sequencing results revealed Nitrosomonas halophila was the sole ammonia oxidizing bacteria (AOB). Thauera and Paracoccus were the main denitrifying bacteria in three biofilm samples. Excitation emission matrix (EEM) spectroscopy coupled with parallel factor analysis (PARAFAC) clarified that proteins were significantly degraded than the other two components (humic-like and fulvic acid-like substance). This study will provide a feasible approach for developing halophilic biological treatment system and present an in-depth insight of the dynamic characteristics of SMP in partial nitrification biofilm system.

Role of Cell Surface Hydrophobicity in the Pathogenesis of Medically-Significant Fungi.

Cell surface hydrophobicity (CSH) is an important cellular biophysical parameter which affects both cell-cell and cell-surface interactions. In dimorphic fungi, multiple factors including the temperature-induced shift between mold and yeast forms have strong effects on CSH with higher hydrophobicity more common at the lower temperatures conducive to filamentous cell growth. Some strains of Cryptococcus neoformans exhibit high CSH despite the presence of the hydrophilic capsule. Among individual yeast colonies from the same isolate, distinct morphologies can correspond to differences in CSH. These differences in CSH are frequently associated with altered virulence in medically-significant fungi and can impact the efficacy of antifungal therapies. The mechanisms for the maintenance of CSH in pathogenic fungi remain poorly understood, but an appreciation of this fundamental cellular parameter is important for understanding its contributions to such phenomena as biofilm formation and virulence.

Insight into probiotic properties of lactic acid bacterial endosymbionts of Apis mellifera L. derived from the Polish apiary.

Taking into account that fructophilic lactic acid bacteria (FLAB) can play an important role in the health of honey bees and can be used as probiotics, phenotypic properties of probiotic interest of Lactobacillus kunkeei (12 strains) and Fructobacillus fructossus bacteria (2 strains), isolated from Apis mellifera gastrointestinal tract, have been studied. We have evaluated survival of tested FLAB in honey bee gut, their susceptibility to antibiotics (ampicillin, erythromycin, tylosin), cell surface hydrophobicity, auto-aggregation ability, co-aggregation with model pathogenic bacteria, biofilm formation capacity, and effect of studied FLAB, added to sucrose syrup bee diet, on longevity of honey bees. The tested FLAB exhibited good gastrointestinal tract tolerance and high antibiotic susceptibility, which are important criteria in the screening of probiotic candidates. It was also found that all FLAB studied have high cell surface hydrophobicity and fulfil next selection criterion for their use as probiotics. Symbionts of A. mellifera showed also auto- and co-aggregation capacities regarded as valuable features for biofilm formation and inhibition of pathogens adhesion to the bee gut cells. Biofilm-development ability is a desired characteristic of probiotic lactic acid bacteria. As indicated by quantitative crystal violet-stained microplate assay and confocal laser scanning microscopy imaging, all studied A. mellifera gut isolates exhibit a biofilm positive phenotype. Moreover, it was also documented, on honey bees kept in cages, that supplementation of A. mellifera sucrose diet with FLAB decreases mortality and improves significantly longevity of honey bees. Presented research showed that A. mellifera FLAB symbionts are good candidates for application as probiotics.