0000000000180040

AUTHOR

Dāvids Fridmanis

0000-0003-0310-0448

Stimulation of sewage sludge treatment by carbon sources and bioaugmentation with a sludge-derived microbial consortium

Abstract Recently, sewage sludge (SS) disposal has become one of the greatest global challenges. In this study, we aimed to evaluate the effect of faba bean straw (Straw-B), wheat straw (Straw-W), and wood-chip pellets (WCP) amended to SS, as well as bioaugmentation (BA), on the physicochemical characteristics and structure of the microbial community of the treated SS. Sixteen days of incubation of SS-containing mixtures revealed the highest efficiency of Straw-W(BA) in terms of SS stabilisation, i.e., the highest and most stable respiration intensity, the lowest ammonia emission, and the highest stimulation effect on the cress seedling growth. Shotgun sequencing data analysis showed that P…

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Microbiome symbionts and diet diversity incur costs on the immune system of insect larvae

Communities of symbiotic microorganisms that colonize the gastrointestinal tract play an important role in food digestion and protection against opportunistic microbes. Diet diversity increases the number of symbionts in the intestines, a benefit that is considered to impose no cost for the host organism. However, less is known about the possible immunological investments that hosts have to make in order to control the infections caused by symbiont populations that increase due to diet diversity. By using taxonomical composition analysis of the 16S rRNA V3 region, we show that Enterococci are the dominating group of bacteria in the midgut of the larvae of the greater wax moth (Galleria mell…

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Lack of significant differences between gastrointestinal tract microbial population structure of Helicobacter pylori-infected subjects before and 2 years after a single eradication event.

Background According to recent estimates 80% of Latvian population is infected with Helicobacter pylori thus their susceptibility to numerous gastric tract diseases is increased. The 1st line H. pylori eradication therapy includes treatment with clarithromycin in combination with amoxicillin or metronidazole and a proton pump inhibitor. However, potential adverse events caused by such therapies to microbiome are insufficiently studied. Objective This study aimed to evaluate the long-term effect of H. pylori eradication on human gastrointestinal tract (GIT) microbiome. Methods The assessment of H pylori eradication impact on GIT microbiome was done by analyzing 120 samples acquired from 60 s…

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Formation of new genes explains lower intron density in mammalian Rhodopsin G protein-coupled receptors

Mammalian G protein-coupled receptor (GPCR) genes are characterised by a large proportion of intronless genes or a lower density of introns when compared with GPCRs of invertebrates. It is unclear which mechanisms have influenced intron density in this protein family, which is one of the largest in the mammalian genomes. We used a combination of Hidden Markov Models (HMM) and BLAST searches to establish the comprehensive repertoire of Rhodopsin GPCRs from seven species and performed overall alignments and phylogenetic analysis using the maximum parsimony method for over 1400 receptors in 12 subgroups. We identified 14 different Ancestral Receptor Groups (ARGs) that have members in both vert…

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Removal of pharmaceuticals from municipal wastewaters at laboratory scale by treatment with activated sludge and biostimulation.

Abstract Municipal wastewater containing 21 pharmaceutical compounds, as well as activated sludge obtained from the aeration tank of the same wastewater treatment plant were used in lab-scale biodegradation experiments. The concentrations of pharmaceutical compounds were determined by high-performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry and ranged from 13.2 ng/L to 51.8 μg/L. Activated sludge was characterized in the terms of phylogenetic and catabolic diversity of microbial community, as well as its morphology. Proteobacteria (24.0%) represented the most abundant phylum, followed by Bacteroidetes (19.8%) and Firmicutes (13.2%). Bioaugmentation of was…

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Identification of glyoxalase 1 polymorphisms associated with enzyme activity.

The glyoxalase system and its main enzyme, glyoxalase 1 (GLO1), protect cells from advanced glycation end products (AGEs), such as methylglyoxal (MG) and other reactive dicarbonyls, the formation of which is increased in diabetes patients as a result of excessive glycolysis. MG is partly responsible for harmful protein alterations in living cells, notably in neurons, leading to their dysfunction, and recent studies have shown a negative correlation between GLO1 expression and tissue damage. Neuronal dysfunction is a common diabetes complication due to elevated blood sugar levels, leading to high levels of AGEs. The aim of our study was to determine whether single nucleotide polymorphisms (S…

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Melanokortīna recptoru saimes evolūcija koncentrējoties uz ACTHR funkcionālo specifiskumu

Elektroniskā versija nesatur pielikumus

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Polymorphisms in FTO and near TMEM18 associate with type 2 diabetes and predispose to younger age at diagnosis of diabetes

Variations in the FTO gene and near the TMEM18 gene are risk factors for common form of obesity, but have also been linked with type 2 diabetes (T2D). Our aim was to investigate the contribution of these variants to risk of T2D in a population in Latvia. Four single nucleotide polymorphisms (SNP) in the first and fourth intronic regions of FTO and one close to TMEM18 were genotyped in 987 patients with T2D and 1080 controls selected from the Latvian Genome Data Base (LGDB). We confirmed association of SNPs in the first intron (rs11642015, rs62048402 and rs9939609) of FTO and rs7561317 representing the TMEM18 locus with T2D. Association between SNP in FTO and T2D remained significant after c…

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A widely used sampling device in colorectal cancer screening programmes allows for large-scale microbiome studies.

We read with interest the article by Passamonti et al ,1 reporting the performance of two different faecal immunochemical tests (FITs) highlighting the importance of standardisation and validation of screening methodologies. Conventionally, laboratory-based FIT is the preferred approach in testing for occult blood in faeces, which includes colorectal cancer screening programmes.2–4 The potential of preserving stable faecal samples in a widely used FIT buffer for microbiome research would enable prospective microbiome studies in generally healthy subjects undergoing colorectal cancer screening. For this purpose, we evaluated faecal sample stability in the commonly used OC-Sensor (Eiken Chemi…

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Evaluation Of Massive Parallel Sequencing As A Diagnostic Tool For Familial Hypercholesterolemia

Abstract Familial hypercholesterolemia (FH) is one of the most common single gene disorders, which is mostly inherited as an autosomal dominant trait. The physical signs of FH are elevated low density lipoprotein cholesterol (LDL-C), elevated total cholesterol (TC) levels and tendon xantomas. Identification and early treatment of affected individuals is desirable and in lack of physical symptoms DNA-based diagnosis provides confirmation of diagnosis and enables early patient management. The majority of FH cases are caused by mutations in four genes (APOB, LADLR, PCSK9, and LDLRAP1). There are commercial kits available for testing of the 20 most common FH causing mutations, but the spectrum …

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Next-generation-sequencing-based identification of familial hypercholesterolemia-related mutations in subjects with increased LDL–C levels in a latvian population

Background Familial hypercholesterolemia (FH) is one of the commonest monogenic disorders, predominantly inherited as an autosomal dominant trait. When untreated, it results in early coronary heart disease. The vast majority of FH remains undiagnosed in Latvia. The identification and early treatment of affected individuals remain a challenge worldwide. Most cases of FH are caused by mutations in one of four genes, APOB, LDLR, PCSK9, or LDLRAP1. The spectrum of disease-causing variants is very diverse and the variation detection panels usually used in its diagnosis cover only a minority of the disease-causing gene variants. However, DNA-based tests may provide an FH diagnosis for FH patients…

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Association of metformin administration with gut microbiome dysbiosis in healthy volunteers

Background Metformin is a widely used first-line drug for treatment of type 2 diabetes. Despite its advantages, metformin has variable therapeutic effects, contraindications, and side effects. Here, for the very first time, we investigate the short-term effect of metformin on the composition of healthy human gut microbiota. Methods We used an exploratory longitudinal study design in which the first sample from an individual was the control for further samples. Eighteen healthy individuals were treated with metformin (2 × 850 mg) for 7 days. Stool samples were collected at three time points: prior to administration, 24 hours and 7 days after metformin administration. Taxonomic composition of…

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Unusual genomic structure: melanocortin receptors in Fugu.

The melanocortin (MC) receptors are found in five subtypes in mammals and chicken, while recent studies have shown that the Fugu (Takifugu rubripes) genome has only four MC receptors and the zebrafish genome has six subtypes. The MC3 receptor seems to be missing from the two closely related pufferfishes, Fugu and Tetraodon (Tetraodon nigroviridis). The MC2 and MC5 receptors in the pufferfish have introns. Moreover, these two receptors are found in a tandem that is remarkably conserved in several vertebrate species. Here, we speculate about the genomic origin of the MC receptors.

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Dominating taxonomic composition of the early life gut microbiota and influencing factors in infants up to seven months of age in Latvia

Abstract It has been hypothesised that the establishment of stable adult microbiota is programmed in infancy, and therefore early life gut colonisation may lead to a lifelong microbiota pattern with significant effects on health. The aim of the study was to analyse the composition of gut microbiota and influencing factors in infants up to seven months of age in Latvia. A cross-sectional study was performed at primary healthcare centres. The parents of healthy infants filled out a questionnaire and brought the child’s faecal sample. 16 rRNS gene sequencing was performed to identify the bacterial taxonomic units. The composition of gut microbiota was compared between children with different r…

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High affinity agonistic metal ion binding sites within the melanocortin 4 receptor illustrate conformational change of transmembrane region 3.

We created a molecular model of the human melanocortin 4 receptor (MC4R) and introduced a series of His residues into the receptor protein to form metal ion binding sites. We were able to insert micromolar affinity binding sites for zinc between transmembrane region (TM) 2 and TM3 where the metal ion alone was able to activate this peptide binding G-protein-coupled receptor. The exact conformation of the metal ion interactions allowed us to predict the orientation of the helices, and remodeling of the receptor protein indicated that Glu100 and Ile104 in TM2 and Asp122 and Ile125 in TM3 are directed toward a putative area of activation of the receptor. The molecular model suggests that a rot…

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Whole-blood transcriptome profiling reveals signatures of metformin and its therapeutic response

Metformin, a biguanide agent, is the first-line treatment for type 2 diabetes mellitus due to its glucose-lowering effect. Despite its wide application in the treatment of multiple health conditions, the glycemic response to metformin is highly variable, emphasizing the need for reliable biomarkers. We chose the RNA-Seq-based comparative transcriptomics approach to evaluate the systemic effect of metformin and highlight potential predictive biomarkers of metformin response in drug-naive volunteers with type 2 diabetes in vivo. The longitudinal blood-derived transcriptome analysis revealed metformin-induced differential expression of novel and previously described genes involved in cholester…

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Cloning of two melanocortin (MC) receptors in spiny dogfish

We report the cloning and characterization of two melanocortin receptors (MCRs) from the spiny dogfish (Squalus acanthias) (Sac). Phylogenetic analysis shows that these shark receptors are orthologues of the MC3R and MC5R subtypes, sharing 65% and 70% overall amino acid identity with the human counterparts, respectively. The SacMC3R was expressed and pharmacologically characterized in HEK293 cells. The radioligand binding results show that this receptor has high affinity for adrenocorticotropic hormone (ACTH)-derived peptides while it has comparable affinity for alpha- and beta-melanocyte stimulating hormone (MSH), and slightly lower affinity for gamma-MSH when compared with the human ortho…

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Selective enrichment of heterotrophic nitrifiers <em>Alcaligenaceae</em> and <em>Alcanivorax</em> spp. from industrial wastewaters

Removal of nitrogen from wastewaters (WW) represents a global problem. The low nitrification rate during WW treatment is often caused by ecotoxicity. This problem is attributed mostly to the industrial WW. Our study was focused on the testing of industrial WW and activated sludge (AS) with the aim to reveal the abundance of nitrifiers and increase their biomass, thus, providing the additional step, i.e., bioaugmentation, within the technological process of WW treatment. Plating of AS on the selective solidified media designated for the 1st and 2nd nitrification stages, resulted in the shift in bacterial community structure with dominated Alcaligenaceae and Alcanivorax for the 1st stage, and…

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The effects of ibuprofen on activated sludge: Shift in bacterial community structure and resistance to ciprofloxacin

Abstract Ibuprofen (IBP) is ranked at the 4th place among 57 pharmaceutical compounds according to the number of citations in prioritization documents. The response of microbial community of activated sludge to IBP was studied at the concentrations of 50–5000 mg/L. Batch incubation was performed in an OxiTop® device for 21 days. The reduction of biological oxygen demand depended on the IBP concentration and varied in the range from 321 to 107 mg O 2 /L. Massive DNA sequencing analysis of the activated sludge revealed that Proteobacteria became more dominant when grown in the presence of IBP. Microbial diversity was reduced in the presence of 500–1000 mg/L IBP, but increased again in the pre…

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Origin of the prolactin-releasing hormone (PRLH) receptors: evidence of coevolution between PRLH and a redundant neuropeptide Y receptor during vertebrate evolution.

We present seven new vertebrate homologs of the prolactin-releasing hormone receptor (PRLHR) and show that these are found as two separate subtypes, PRLHR1 and PRLHR2. Analysis of a number of vertebrate sequences using phylogeny, pharmacology, and paralogon analysis indicates that the PRLHRs are likely to share a common ancestry with the neuropeptide Y (NPY) receptors. Moreover, a micromolar level of NPY was able to bind and inhibit completely the PRLH-evoked response in PRLHR1-expressing cells. We suggest that an ancestral PRLH peptide started coevolving with a redundant NPY binding receptor, which then became PRLHR, approximately 500 million years ago. The PRLHR1 subtype was shown to have…

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Data from: Microbiome symbionts and diet diversity incur costs on the immune system of insect larvae

Communities of symbiotic microorganisms that colonize the gastrointestinal tract play an important role in food digestion and protection against opportunistic microbes. Diet diversity increases the number of symbionts in the intestines, a benefit that is considered to impose no cost for the host organism. However, less is known about the possible immunological investments that hosts have to make in order to control the infections caused by symbiont populations that increase due to diet diversity. By using taxonomical composition analysis of the 16S rRNA V3 region, we show that Enterococci are the dominating group of bacteria in the midgut of the larvae of the greater wax moth (Galleria mell…

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