Carbon dioxide and trace oxygen concentrations impact growth and product formation of the gut bacterium Phocaeicola vulgatus.

BACKGROUND: The promising yet barely investigated anaerobic species Phocaeicola vulgatus (formerly Bacteroides vulgatus) plays a vital role for human gut health and effectively produces organic acids. Among them is succinate, a building block for high-value-added chemicals. Cultivating anaerobic bacteria is challenging, and a detailed understanding of P. vulgatus growth and metabolism is required to improve succinate production. One significant aspect is the influence of different gas concentrations. CO2 is required for the growth of P. vulgatus. However, it is a greenhouse gas that should not be wasted. Another highly interesting aspect is the sensitivity of P. vulgatus towards O2. In this work, the effects of varying concentrations of both gases were studied in the in-house developed Respiratory Activity MOnitoring System (RAMOS), which provides online monitoring of CO2, O2, and pressure under gassed conditions. The RAMOS was combined with a gas mixing system to test CO2 and O2 concentrations in a range of 0.25-15.0 vol% and 0.0-2.5 vol%, respectively. RESULTS: Changing the CO2 concentration in the gas supply revealed a CO2 optimum of 3.0 vol% for total organic acid production and 15.0 vol% for succinate production. It was demonstrated that the organic acid composition changed depending on the CO2 concentration. Furthermore, unrestricted growth of P. vulgatus up to an O2 concentration of 0.7 vol% in the gas supply was proven. The viability decreased rapidly at concentrations larger than or equal to 1.3 vol% O2. CONCLUSIONS: The study showed that P. vulgatus requires little CO2, has a distinct O2 tolerance and is therefore well suited for industrial applications.

The role of non-classical and chain-related human leukocyte antigen polymorphisms in laryngeal squamous cell carcinoma.

BACKGROUND: Laryngeal squamous cell carcinoma (LSCC) is the major pathological subtype of laryngeal cancer. It has been shown that alterations of the expression of non-classical human leukocyte antigens (HLA) and the chain-related MIC molecules by malignant cells can lead to escape from the immune system control and certain allele variants may participate in immune editing and therefore be associated with modulation of cancer risk. The aim of the present study was to investigate the role of non-classical HLA class Ib and chain-related MIC polymorphisms, determined at the allelic level by next-generation sequencing (NGS), in patients from the Bulgarian population, diagnosed with LSCC. MATERIALS AND METHODS: In the present study DNA samples from 48 patients with LSCC were used. Data was compared to 63 healthy controls analysed in previous studies. HLA genotyping was performed by using the AlloSeq Tx17 early pooling protocol and the library preparation AlloSeq Tx17 kit (CareDx). Sequencing was performed on MiniSeq sequencing platform (Illumina) and HLA genotypes were assigned with the AlloSeq Assign analysis software v1.0.3 (CareDx) and the IPD-IMGT/HLA database 3.45.1.2. RESULTS: The HLA disease association tests revealed a statistically significant predisposing association of HLA-F*01:01:02 (Pc = 0.0103, OR = 24.0194) with LSCC, while HLA-F*01:01:01 (Pc = 8.21e-04, OR = 0.0485) has a possible protective association. Additionally we observed several haplotypes with statistically significant protective and predisposing associations. The strongest association was observed for F*01:01:01-H*01:01:01 (P = 0.0054, haplotype score=-2.7801). CONCLUSION: Our preliminary study suggests the involvement of HLA class Ib in cancer development and the possible role of the shown alleles as biomarkers of LSCC.

Development of a novel defined minimal medium for Gluconobacter oxydans 621H by systematic investigation of metabolic demands.

BACKGROUND: Historically, complex media are used for the cultivation of Gluconobacter oxydans in industry and research. Using complex media has different drawbacks like higher costs for downstream processing and significant variations in fermentation performances. Synthetic media can overcome those drawbacks, lead to reproducible fermentation performances. However, the development of a synthetic medium is time and labour consuming. Detailed knowledge about auxotrophies and metabolic requirements of G. oxydans is necessary. In this work, we use a systematic approach applying the in-house developed µRAMOS technology to identify auxotrophies and develop a defined minimal medium for cultivation of G. oxydans fdh, improving the production process of the natural sweetener 5-ketofructose. RESULTS: A rich, defined synthetic medium, consisting of 48 components, including vitamins, amino acids and trace elements, was used as a basis for medium development. In a comprehensive series of experiments, component groups and single media components were individually omitted from or supplemented to the medium and analysed regarding their performance. Main components like salts and trace elements were necessary for the growth of G. oxydans fdh, whereas nucleotides were shown to be non-essential. Moreover, results indicated that the amino acids isoleucine, glutamate and glycine and the vitamins nicotinic acid, pantothenic acid and p-aminobenzoic acid are necessary for the growth of G. oxydans fdh. The glutamate concentration was increased three-fold, functioning as a precursor for amino acid synthesis. Finally, a defined minimal medium called 'Gluconobacter minimal medium' was developed. The performance of this medium was tested in comparison with commonly used media for Gluconobacter. Similar/competitive results regarding cultivation time, yield and productivity were obtained. Moreover, the application of the medium in a fed-batch fermentation process was successfully demonstrated. CONCLUSION: The systematic investigation of a wide range of media components allowed the successful development of the Gluconobacter minimal medium. This chemically defined medium contains only 14 ingredients, customised for the cultivation of G. oxydans fdh and 5-ketofructose production. This enables a more straightforward process development regarding upstream and downstream processing. Moreover, metabolic demands of G. oxydans were identified, which further can be used in media or strain development for different processes.

Associations of high-resolution-typing-defined MICA and MICB polymorphisms, and the levels of soluble MICA and MICB with Oral Squamous Cell Carcinoma in Bulgarian patients.

BACKGROUND: Oral Squamous Cell Carcinoma (OSCC) is a malignancy characterized by an aggressive tumor growth and significant mortality. Clarifying mechanisms responsible for immunomodulation are among the main challenges for the development of personalized approaches for the management of patients with Oral Squamous Cell Carcinoma. The aim of the present study was to analyze the relevance of MICA and MICB to Oral Squamous Cell Carcinoma pathogenesis focusing on allele polymorphisms and the levels of soluble MICA and MICB molecules. MATERIALS AND METHODS: 73 patients diagnosed with Oral Squamous Cell Carcinoma and 149 healthy controls from the Bulgarian population were included in the study. MICA and MICB polymorphism was analyzed at high-resolution level using Next-Generation Sequencing. Serum levels of soluble MICA and MICB molecules were measured by ELISA. RESULTS: Our results show significant protective association with MICB*002:01, while relatively rare alleles MICB*018, *019, and *020 were observed with statistically significant increased frequency in Oral Squamous Cell Carcinoma patients compared to controls. Additionally, a predisposing association was observed for MICA*008:01-MICB*019 haplotype. A correlation analysis between functionally relevant MICA polymorphisms and sMICA showed that homozygosity for MICA-A5.1 or 129Val in OSCC patients was associated with significantly higher serum levels of sMICA. CONCLUSION: This is the first study showing significant associations between MICB alleles and Oral Squamous Cell Carcinoma and suggesting the possible role of MICB in immunosurveillance in Oral Squamous Cell Carcinoma development. Observed correlations between the levels of soluble MICA molecules and functionally relevant polymorphisms might represent a further step toward a better understanding of molecular mechanisms of Oral Squamous Cell Carcinoma and developing strategies for therapeutic targeting harnessing effective immunosurveillance.

Paromomycin is superior to metronidazole in Dientamoeba fragilis treatment.

Dientamoeba fragilis is a trichomonad parasite of the human intestine that is found worldwide. However, the biological cycle and transmission of this parasite have yet to be elucidated. Although its pathogenic capacity has been questioned, there is increasing evidence that clinical manifestations vary greatly. Different therapeutic options with antiparasitic drugs are currently available; however, very few studies have compared the effectiveness of these drugs. In the present longitudinal study, we evaluate 13,983 copro-parasitological studies using light microscopy of stools, during 2013-2015, in Terrassa, Barcelona (Spain). A total of 1150 (8.2%) presented D. fragilis. Of these, 739 episodes were finally analyzed: those that involved a follow-up parasitology test up to 3 months later, corresponding to 586 patients with gastrointestinal symptoms (53% under 15 years of age). Coinfection by Blastocystis hominis was present in 33.6% of the subjects. Our aim was to compare therapeutic responses to different antiparasitic drugs and the factors associated with the persistence of D. fragilis post-treatment. Gender, age, and other intestinal parasitic coinfections were not associated with parasite persistence following treatment. Metronidazole was the therapeutic option in most cases, followed by paromomycin: 65.4% and 17.5% respectively. Paromomycin was found to be more effective at eradicating parasitic infection than metronidazole (81.8% vs. 65.4%; p = 0.007), except in children under six years of age (p = 0.538). Although Dientamoeba fragilis mainly produces mild clinical manifestations, the high burden of infection means we require better understanding of its epidemiological cycle and pathogenicity, as well as adequate therapeutic guidelines in order to adapt medical care and policies to respond to this health problem.

Factors influencing cardiometabolic risk profile in patients with psoriasis.

BACKGROUND: Psoriasis has been associated with metabolic syndrome and with an increased cardiovascular risk especially in patients with severe disease. The goal of this study was to estimate the prevalence of metabolic syndrome and other cardiovascular risk factors and its association with the psoriasis severity, sex and age. METHODS: Consecutive patients with psoriasis were enrolled in a prospective study over a 1-year period. Blood samples were collected. Psoriasis area and severity index (PASI) and body surface area scores and two dermatology quality of life (DQOL) questionnaires were used to evaluate psoriasis severity and the impact of the disease. RESULTS: Altogether 178 patients were included, of whom 44% had moderate-severe psoriasis. The overall prevalence of metabolic syndrome was 30% (men 34%, women 26%) without significant differences between patients with severe and mild disease. Age and menopause appeared to increase the risk for metabolic syndrome. Patients with severe psoriasis smoked more heavily, were more likely to have diabetes or insulin resistance and had higher homocysteine and lower high density lipoprotein cholesterol (HDL-C) levels than patients with mild psoriasis (P < 0.05). In women, a higher waist circumference was observed. Women had higher HDL-C levels and lower smoking and alcohol consumption rates. In accordance with the systematic coronary risk evaluation system, 18% of the patients had a high 10-year risk of fatal cardiovascular disease. CONCLUSIONS: Psoriasis severity was associated with diabetes, insulin-resistance, smoking habit and higher cardiovascular risk. Metabolic syndrome was related to age and menopause but not to psoriasis severity.

BPIFA1 Gene Expression in the Human Middle Ear Mucosa.

OBJECTIVE: The bactericidal/permeability-increasing, fold-containing family member A1 (BPIFA1) gene codes a secretory protein (BPIFA1), which is present in the respiratory tract mucosa, and is part of the innate immune system. This study aimed to prove that BPIFA1 gene expression exists in the human middle ear mucosa. MATERIALS AND METHODS: In total, 32 patients participated in the study between March 2016 and September 2016. Seventeen patients had chronic otitis media with cholesteatoma (COMC) and 15 had bilateral sensorineural hearing loss (BSHL). The patients with COMC underwent radical mastoidectomy with cholesteatoma removal and those with BSHL underwent cochlear implantation. Part of the processus mastoideus mucosa was examined for BPIFA1 gene expression and the two groups were compared. RESULTS: For the first time, BPIFA1 gene expression was examined in the mucosa of the human middle ear, and it was verified in 100% (n=32) of the participants. We confirmed that there is a difference in the BPIFA1 expression in 83.33% of the patients with COMC compared to the patients with BSHL but this difference was not statistically significant (p=0.947; probably due to the low number of participants in this group). CONCLUSION: It is highly likely that the BPIFA1 protein participates in the non-specific immune defense of the middle ear and is relevant to the pathogenesis of the inflammatory diseases of the middle ear.