Proteomic Analysis of m.8296A>G Variation in the Mitochondrial tRNA Lys Gene.

Variation in the mitochondrial tRNA Lys gene at position 8296 was previously found to be associated with maternally inherited diabetes mellitus and deafness, hypertrophic cardiomyopathy, myoclonic epilepsy with ragged-red fibers and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The pathogenicity of the m.8296A>G variation is unclear. In this study, we aimed to analyze the mitochondrial proteome in a patient with m.8296A>G variation to elucidate the effects of this mutation at the protein level. Whole-exome sequencing and mitochondrial genome analysis were performed in a patient with sensorineural hearing impairment, cognitive impairment, leukodystrophy, migraine-like headaches, and gastrointestinal dysmotility. Mitochondrial genome analysis identified a homoplasmic m.8296A>G variation in the mitochondrial tRNA Lys gene in the proband and unaffected mother. Global mitochondrial proteome analysis was carried out in the muscle mitochondria of the index patient and a control subject. Comparative muscle mitochondrial proteome analysis revealed a total of 13 nuclear-encoded mitochondrial proteins differently expressed with respect to the control. Ten of the 13 proteins were downregulated. Most of the proteins were involved in ATP synthesis and Krebs cycle and have strong interactions with each other. We considered the m.8296A>G variation to be pathogenic with variable penetrance for our patient's phenotype, and this variation led to different expressions of nuclear-encoded proteins involved in energy metabolism.

BEND4 as a Candidate Gene for an Infection-Induced Acute Encephalopathy Characterized by a Cyst and Calcification of the Pons and Cerebellar Atrophy.

Three siblings born to Turkish parents from the same village had normal brain development until acute neurological deterioration between 12 months and 8 years of age. Consequent loss of all acquired motor, social, and language functions following infections was associated with a pontine cyst, calcification, and cerebellar atrophy. Exome sequencing revealed a homozygous c.1297G>A (p.Gly433Ser) alteration in BEND4, which was predicted to be deleterious in in silico analysis tools and segregated in multiple affected individuals in the family. BEND4 has not been associated with any existing disease. Immunofluorescence microscopy analysis of wild-type and mutant BEND4 expressing Vero cells showed nuclear and cytoplasmic localization. Wild-type BEND4 displayed a network-like distribution, whereas mutant BEND4 showed a juxtanuclear distribution pattern. Differential proteome analysis of Vero cells expressing BEND4 revealed that mutant BEND4 expression caused selective increase in reticulocalbin-1 and endoplasmic reticulum resident protein-29. Both proteins are associated with the endoplasmic reticulum and are primarily involved in protein processing and folding pathways. Any defect or stress in protein folding creates stress on cells and may cause chronic damage. This is the first study showing that pathogenic BEND4 variants may lead to an infection-induced acute necrotizing encephalopathy as demonstrated in characteristic neuroimaging findings.

MEFV mutation frequencies in a Turkish cohort with low prevalence of familial Mediterranean fever

Background/aim: Familial Mediterranean fever (FMF) is a genetically recessive autoinflammatory disease caused by mutations in the Mediterranean fever (MEFV) gene. The aim of this study was to investigate the frequencies of the most common MEFV mutations among a sample of healthy individuals from the Havsa population of European Turkey, where FMF is less prevalent compared to Asian Turkey. Materials and methods: The study group consisted of 263 unrelated healthy adults. All of the participants were analyzed for the M694V, V726A, M680I, and E148Q mutations in the MEFV gene. Results: In total, 25 of the 263 individuals carried MEFV mutations (9.5%). The observed allele frequencies were 1.5% for M694V (95% confidence interval [CI] 0.5-2.5), 2.6% for E148Q (95% CI 1.6-3.9), 0.5% for M680I (95% CI 0.0-1.1), and 0.0% for V726A. The frequencies of the M694V, M680I, and E148Q mutations were not significantly different from allele frequencies (approximately 20%) determined for other regions of Turkey where FMF is more prevalent. Conclusion: These data suggest that the positivity of the MEFV gene mutation tests have lower predictive value in a population with low FMF prevalence.

Identification of red blood cell membrane defects in a patient with hereditary spherocytosis using next­generation sequencing technology and matrix­assisted laser desorption/ionization time­of­flight mass spectrometry.

Hereditary spherocytosis (HS) is characterized by the morphological transformation of erythrocytes into a spherical shape due to a hereditary defect in cell membrane proteins (ghosts) associated with disruption of erythrocyte skeletal structures. Contrary to the literature, pores were detected in the erythrocytes of a patient with HS. The aim of the present study was to determine the affected proteins and genes that were responsible for the pores. Ghost isolation was performed to determine the proteins responsible for the pores observed on the erythrocytes of the patient. Erythrocyte membrane proteins were visualized using SDS­PAGE. Exome and matrix­assisted laser desorption/ionization time­of­flight mass spectrometry (MALDI TOF MS) analyses were used to identify the genes and proteins responsible for the observed defect. Quantitative protein assessments were performed using MALDI TOF MS. A difference was detected in the components of the erythrocyte membrane proteins. Band 3 and protein 4.2, which serve a particular role in membrane structure, decreased 4.573 and 4.106 fold, respectively. Through proteomic analyses, a non­synonymous exonic mutation region was identified in the Golgi membrane protein 1 (GOLM1) gene (Chr9 rs142242230). Sorting Intolerant From Tolerant and Polymorphism Phenotyping Scores, Likelihood Ratio Tests and MutationTaster revealed that the mutation was deleterious. The pores observed in the morphology of the erythrocytes may have developed due to the decrease in these proteins, which reside in the erythrocyte membrane structure. Furthermore, genetic profiling of the patient with HS and her family was conducted in the present study. Next­generation sequencing was used, and the genetic source of HS was identified as a GOLM1 gene mutation. The assessment of specific molecular defects is often not performed as the majority of mutations are unique to a family. However, molecular analyses should be performed in severe cases where prenatal diagnosis is required, or for unique HS phenotypes to aid scientific investigation.

Investigation of Gene Expressions of Myeloma Cells in the Bone Marrow of Multiple Myeloma Patients by Transcriptome Analysis

Background: Multiple myeloma is a plasma cell dyscrasia characterized by transformation of B cells into malignant cells. Although there are data regarding the molecular pathology of multiple myeloma, the molecular mechanisms of the disease have not been fully elucidated. Aims: To investigate the gene expression profiles in bone marrow myeloma cells via RNA-sequencing technology. Study Design: Cell study. Methods: Myeloma cells from four patients with untreated multiple myeloma and B cells from the bone marrow of four healthy donors were sorted using a FACSAria II flow cytometer. The patient pool of myeloma cells and the control pool of B cells were the two comparative groups. A transcriptome analysis was performed and the results were analyzed using bioinformatics tools. Results: In total, 18.806 transcripts (94.4%) were detected in the pooled multiple myeloma patient cells. A total of 992 regions were detected as new exon candidates or alternative splicing regions. In addition, 490 mutations (deletions or insertions), 1.397 single nucleotide variations, 415 fusion transcripts, 132 frameshift mutations, and 983 fusions, which were reported before in the National Center for Biotechnology Information, were detected with unknown functions in patients. A total of 35.268 transcripts were obtained (71%) (25.355 transcripts were defined previously) in the control pool. In this preliminary study, the first 50 genes were analyzed with the MSigDB, Enrichr, and Panther gene set enrichment analysis programs. The molecular functions, cellular components, pathways, and biological processes of the genes were obtained and statistical values were determined using bioinformatics tools and are presented as a supplemental file. Conclusion: EEF1G, ITM2C, FTL, CLPTM1L, and CYBA are identified as possible candidate genes associated with myelomagenesis.

Spleen Tyrosine Kinase Inhibitor TAK-659 Prevents Splenomegaly and Tumor Development in a Murine Model of Epstein-Barr Virus-Associated Lymphoma.

Epstein-Barr virus (EBV) is associated with several B and epithelial cell cancers. EBV-encoded latent membrane protein 2A (LMP2A) contributes to cellular transformation by mimicking B cell receptor signaling. LMP2A/MYC double transgenic mice develop splenomegaly and B cell lymphoma much faster than MYC transgenic mice do. In this study, we explored the potential therapeutic efficacy of a novel spleen tyrosine kinase (SYK) and FLT3 inhibitor TAK-659 for development of a treatment option for EBV-associated malignancies. In our transgenic model, TAK-659 treatment totally abrogated splenomegaly and tumor development in LMP2A/MYC mice in both pretumor and tumor cell transfer experiments. TAK-659 treatment killed tumor cells, but not host cells within the spleen and tumors. Furthermore, TAK-659 treatment abrogated metastasis of tumor cells into bone marrow. Our data also show that TAK-659 inhibits SYK phosphorylation and induces apoptosis in LMP2A/MYC tumor cells at low nanomolar concentrations. Therefore, TAK-659 may provide an effective therapeutic option for treatment of LMP2A-positive EBV-associated malignancies and should be explored further in clinical trials.IMPORTANCE The novel SYK and FLT3 inhibitor TAK-659 prevents the enlargement of spleen and tumor development in a mouse model of EBV-associated lymphoma by counteracting the activation of cellular kinase SYK through the viral LMP2A gene by inducing cell death in tumor cells but not in nontumor cells. These findings indicate that TAK-659 may be a very effective nontoxic therapeutic molecule especially for EBV-positive hematologic malignancies.

Mutations in Core Gene Region of Hepatitis B Virus in Patients with Chronic Hepatitis B.

BACKGROUND: The HBV core protein plays a major role in host immune response. Mutations occurring in the HBV core gene may cause alterations in the major epitopes being effective in the host immune response. Until now, the persistent effects of core gene mutations on HBV infections have not been fully understood. The aim of this study is to analyze the core gene mutations for epitopes in the T lymphocytes [T helper (Th) and cytotoxic (CTL)] and B cell and C terminal region in patients with chronic hepatitis using ultra-deep pyrosequencing (UDPS) method. METHODS: Eleven patients with chronic hepatitis B infection were included in the study. Amplification of the core gene was performed by a conventional PCR method. Mutations in the epitopes for T lymphocytes (Th and CTL) and B cell and in the C terminal region of HBV core gene were screened by UDPS. These mutations were analyzed in HBeAg positive and negative patients. RESULTS: The minimum percentages of amino acid substitutions were found with 0.9% in HBeAg positive patients and 1.2% in negative patients. The number of missense mutation was higher in patients with HBeAg positive than negative patients (p < 0.005). The number of amino acid substitutions in the region of aa49 - 69 in the Th epitopes was found to be the highest in both HBeAg positive and negative patients. The mutation frequency was higher in the C-terminal region of the core protein compared to the Th, CTL, and B cell regions and these were more common in subjects with high-grade fibrosis. Some types of mutations (V27I, R47H, Y132I, R174STOP, S181P, Q182K) were only detected in subjects with liver cirrhosis. CONCLUSIONS: Unlike literature, our results show that there is no significant increase in number of mutations in the core gene of the virus during the anti-HBe positive period. The role of low abundance variants and mutations in the immune system can be understood using methods such as UDPS in the near future.

Association of Pro-apoptotic Bad Gene Expression Changes with Benign Thyroid Nodules.

BACKGROUND/AIM: This study aimed to investigate the role of the mitochondrial apoptotic pathway in benign thyroid nodules. MATERIALS AND METHODS: Paired samples of nodular and normal tissues were collected from 26 patients with nodular goiters undergoing thyroidectomy. Variable expression of Bcl-2, Bax and Bad genes were evaluated by quantitative PCR. RESULTS: Expression level of Bad gene in nodules was found to be significantly decreased compared to normal tissues (p=0.049). A positive correlation was observed between nodule size and Bad expression levels (correlation coefficient=0.563, p=0.004); and this correlation was stronger in hot nodules (n=18, correlation coefficient=0.689, p=0.003). No significant difference was observed between nodular and normal tissue expressions of Bax and Bcl-2. CONCLUSION: These results suggest that Bad expression correlates with the size of benign thyroid nodules and also its relatively lower expression in nodules, warrant further investigation.

The association between P selectin glycoprotein ligand 1 gene variable number of tandem repeats polymorphism and risk of thrombosis in Behçet's disease.

OBJECTIVES: Behçet's disease (BD) has been recognized as an unclassified type of vasculitis with an accompanying tendency to thrombosis. No disease-specific pathology has been demonstrated so far to explain the prothrombotic state, and this predisposition is considered to be associated with endothelial activation/dysfunction. P-selectin glycoprotein ligand-1 (PSGL-1) variable number of tandem repeat (VNTR) polymorphism has an impact on the protein length, and heterozygosity affect of the PSGL-1 to P-selectin interaction, which has been found to be associated with an increased risk of thrombosis in patients with antiphospholipid syndrome. We aimed to analyze the association of PSGL-1 gene polymorphism, in a group of BD patients with and without thrombosis. METHODS: The study group consisted of 136 BD patients (112 male, 24 female) with thrombosis, 120 BD patients without thrombosis (54 male, 66 female) during at least 5 years disease course, and 190 healthy controls (103 male, 87 female) All patients fulfilled the International Study Group criteria for classification of BD. Genotyping for the PSGL-1 gene exon 2 VNTR polymorphism was carried out with the amplification of genomic DNA and running of the polymerase chain reaction product on agarose gel electrophoresis. RESULTS: The frequency of heterozygous genotypes (AB+AC+BC) was greater in BD patients with thrombosis compared to BD patients without thrombosis (33.1% vs. 20.8%, P = 0.028, odds ratio = 1.85). However, the increased frequency of heterozygous genotypes in BD patients with thrombosis did not reach a statistically significant level compared to healthy controls (33.1% vs. 32.6%). CONCLUSIONS: PSGL-1 VNTR polymorphism may have limited contribution to the thrombotic tendency in patients with BD.

Myophosphorylase (PYGM) mutations determined by next generation sequencing in a cohort from Turkey with McArdle disease.

This study aimed to identify PYGM mutations in patients with McArdle disease from Turkey by next generation sequencing (NGS). Genomic DNA was extracted from the blood of the McArdle patients (n = 67) and unrelated healthy volunteers (n = 53). The PYGM gene was sequenced with NGS and the observed mutations were validated by direct Sanger sequencing. A diagnostic algorithm was developed for patients with suspected McArdle disease. A total of 16 deleterious PYGM mutations were identified, of which 5 were novel, including 1 splice-site donor, 1 frame-shift, and 3 non-synonymous variants. The p.Met1Val (27-patients/11-families) was the most common PYGM mutation, followed by p.Arg576* (6/4), c.1827+7A>G (5/4), c.772+2_3delTG (5/3), p.Phe710del (4/2), p.Lys754Asnfs (2/1), and p.Arg50* (1/1). A molecular diagnostic flowchart is proposed for the McArdle patients in Turkey, covering the 6 most common PYGM mutations found in Turkey as well as the most common mutation in Europe. The diagnostic algorithm may alleviate the need for muscle biopsies in 77.6% of future patients. A prevalence of any of the mutations to a geographical region in Turkey was not identified. Furthermore, the NGS approach to sequence the entire PYGM gene was successful in detecting a common missense mutation and discovering novel mutations in this population study.

Analysis of Hepatitis C Virus NS5A Region in Patients with Cirrhosis Using an Ultra-Deep Pyrosequencing Method.

BACKGROUND: HCV (Hepatitis C Virus) is genetically more diverse than HBV and HIV (Human Immunodeficiency Virus) and exists as quasispecies within infected individuals. This is due to the lack of efficient proofreading of the viral RNA-dependent RNA polymerase. Consequently, quasispecies emerge depending on the mutation rate of the viral polymerase, which may display a high level of genetic variability in a population. In infected individuals, HCV replicates and circulates as quasispecies composed of a complex mixture of different but closely related genomes that undergoes continuous change due to competitive selection and cooperation between arising mutants. The aim of this study is to investigate mutations in the NS5A region as a whole, including ISDR, PKRBD, IRRDR, and V3 of HCV genotype 1b cirrhosis patients being naive and nonresponders, treated with IFN (interferon) + ribavirin (RBN) by using an ultra-deep pyrosequencing method (UDPS). METHODS: During the study, five patients (four females, and one male, mean age 59.8 ± 11 years) with HCV related cirrhosis were analyzed. Three patients received IFN + RBN for six months, but two patients did not receive any therapy. HCV-RNA concentrations in patients' sera were determined using a COBAS AMPLICOR HCV MONITOR Test, Version 2.0. Genotyping was performed by using a commercial reverse hybridization method, Line Probe Assay. The quasispecies for the NS5A region were investigated using UDPS. RESULTS: All five patients were HCV genotype 1b (Mean Child-Pugh score 7.2 ± 1.9, 2 pts Child A, 2 pts Child B, and one pt Child C) but only one patient had hepatocellular carcinoma (HCC). A total of 19 different mutations were detected in each of the five patients (ranging from 3 to 6 mutations per patient). In all five patients, several mutations in the ISDR and PKR-BD regions were detected. On the other hand, mutations in the V3 and IRRDR regions were only detected in one patient. CONCLUSIONS: UDPS is a new sequencing technology and a very sensitive method in detection of quasispecies with low frequency NS5A region mutations. These mutations may affect the antiviral response and development of HCC. However, further studies in larger number of patients should be conducted to clarify this hypothesis.

Origin and spread of human mitochondrial DNA haplogroup U7.

Human mitochondrial DNA haplogroup U is among the initial maternal founders in Southwest Asia and Europe and one that best indicates matrilineal genetic continuity between late Pleistocene hunter-gatherer groups and present-day populations of Europe. While most haplogroup U subclades are older than 30 thousand years, the comparatively recent coalescence time of the extant variation of haplogroup U7 (~16-19 thousand years ago) suggests that its current distribution is the consequence of more recent dispersal events, despite its wide geographical range across Europe, the Near East and South Asia. Here we report 267 new U7 mitogenomes that - analysed alongside 100 published ones - enable us to discern at least two distinct temporal phases of dispersal, both of which most likely emanated from the Near East. The earlier one began prior to the Holocene (~11.5 thousand years ago) towards South Asia, while the later dispersal took place more recently towards Mediterranean Europe during the Neolithic (~8 thousand years ago). These findings imply that the carriers of haplogroup U7 spread to South Asia and Europe before the suggested Bronze Age expansion of Indo-European languages from the Pontic-Caspian Steppe region.

Dense genotyping of immune-related loci implicates host responses to microbial exposure in Behçet's disease susceptibility.

We analyzed 1,900 Turkish Behçet's disease cases and 1,779 controls genotyped with the Immunochip. The most significantly associated SNP was rs1050502, a tag SNP for HLA-B*51. In the Turkish discovery set, we identified three new risk loci, IL1A-IL1B, IRF8, and CEBPB-PTPN1, with genome-wide significance (P < 5 × 10-8) by direct genotyping and ADO-EGR2 by imputation. We replicated the ADO-EGR2, IRF8, and CEBPB-PTPN1 loci by genotyping 969 Iranian cases and 826 controls. Imputed data in 608 Japanese cases and 737 controls further replicated ADO-EGR2 and IRF8, and meta-analysis additionally identified RIPK2 and LACC1. The disease-associated allele of rs4402765, the lead marker at IL1A-IL1B, was associated with both decreased IL-1α and increased IL-1ß production. ABO non-secretor genotypes for two ancestry-specific FUT2 SNPs showed strong disease association (P = 5.89 × 10-15). Our findings extend the list of susceptibility genes shared with Crohn's disease and leprosy and implicate mucosal factors and the innate immune response to microbial exposure in Behçet's disease susceptibility.

Association of Enteric Protist Blastocystis spp. and Gut Microbiota with Hepatic Encephalopathy.

BACKGROUND AND AIMS: Hepatic encephalopathy (HE) is a serious neuropsychiatric sequela emerging in the advanced stages of cirrhosis. The gut microbiota plays an important role in the development of HE. The aim of the study was to analyze the dynamic interplay between microbiota and Blastocystis in cirrhotic patients with or without encephalopathy. METHODS: The study was designed as cross-sectional study. A total of 37 patients from the Ankara city, admitted to the University Hospital within a 6-month period prior to enrolment into the study were included in the study. After the regular health checks, clinical histories, clinical examinations, and Psychometric HE Score (PHES) points, patients' MELD and CTP scores were recorded. The fecal microbiota configurations were characterized by targeting hypervariable regions V3 and V4 of the 16S rRNA gene using Illumina MiSeq System. RESULTS: Blastocystis spp. were detected in 21.6% (n = 8) of all cirrhotic patients. When those were analyzed by subgroups, four of them were subtype 2, three were subtype 3 and one was subtype 1. Blastocystis spp. were not found in any of the patients with HE; however, they were detected in 38.1% of the patients without HE. Also the increase in the bacterial diversity was observed along with the absence of Blastocystis. It was suggested that there was an inverse relationship between Blastocystis spp. and advanced stages of HE and the structure and composition of gut microbiota. CONCLUSION: The absence of Blastocystis spp. is associated with the HE severity and dysbiosis in the gut microbiota.

The Immunostimulatory Effect of Lactic Acid Bacteria in a Rat Model.

BACKGROUND: Probiotics are "live", beneficial microbes that provide important health benefits in their hosts. There is significant interest in the modulation and regulation of the immune function by probiotics. OBJECTIVE: To investigate the immunomodulatory effects of a probiotic mixture, including Lactobacillus and Bifidobacterium species, by detecting serum cytokine and immunoglobulin levels. METHODS: The rats were randomly divided into 4 groups. The first group was "Control group" and other 3 groups were probiotic application groups who received different doses of probiotics. The probiotic mixture included 12 probiotic bacteria, mostly Lactobacillus and Bifidobacterium strains. Probiotic mixture was administered to rats for 12 consecutive days. TNF-α, TGF-ß, IL-1-ß, IL-6, and IL-10 levels as well as serum IgG and IgA concentrations were detected in the sera after 12 days. RESULTS: Probiotics led to a decrease in the levels of TNF-α, IL-6 and TGF-ß; however, they led to increase in the serum levels of IL-10, IgG and IgA. There were significant differences between control group and probiotic application groups (p<0.05). CONCLUSION: These data suggest that the commensal microbiota are important for stimulating both proinflammatory and regulatory responses in order to rapidly clear infections and minimize inflammation-associated tissue damage.

Recombinant plasmid-based quantitative Real-Time PCR analysis of Salmonella enterica serotypes and its application to milk samples.

The aim of the current study was to develop, a new, rapid, sensitive and quantitative Salmonella detection method using a Real-Time PCR technique based on an inexpensive, easy to produce, convenient and standardized recombinant plasmid positive control. To achieve this, two recombinant plasmids were constructed as reference molecules by cloning the two most commonly used Salmonella-specific target gene regions, invA and ttrRSBC. The more rapid detection enabled by the developed method (21 h) compared to the traditional culture method (90 h) allows the quantitative evaluation of Salmonella (quantification limits of 10(1)CFU/ml and 10(0)CFU/ml for the invA target and the ttrRSBC target, respectively), as illustrated using milk samples. Three advantages illustrated by the current study demonstrate the potential of the newly developed method to be used in routine analyses in the medical, veterinary, food and water/environmental sectors: I--The method provides fast analyses including the simultaneous detection and determination of correct pathogen counts; II--The method is applicable to challenging samples, such as milk; III--The method's positive controls (recombinant plasmids) are reproducible in large quantities without the need to construct new calibration curves.

Water as Source of Francisella tularensis Infection in Humans, Turkey.

Francisella tularensis DNA extractions and isolates from the environment and humans were genetically characterized to elucidate environmental sources that cause human tularemia in Turkey. Extensive genetic diversity consistent with genotypes from human outbreaks was identified in environmental samples and confirmed water as a source of human tularemia in Turkey.

Genomic analysis reveals the biotechnological and industrial potential of levan producing halophilic extremophile, Halomonas smyrnensis AAD6T.

Halomonas smyrnensis AAD6T is a gram negative, aerobic, and moderately halophilic bacterium, and is known to produce high levels of levan with many potential uses in foods, feeds, cosmetics, pharmaceutical and chemical industries due to its outstanding properties. Here, the whole-genome analysis was performed to gain more insight about the biological mechanisms, and the whole-genome organization of the bacterium. Industrially crucial genes, including the levansucrase, were detected and the genome-scale metabolic model of H. smyrnensis AAD6T was reconstructed. The bacterium was found to have many potential applications in biotechnology not only being a levan producer, but also because of its capacity to produce Pel exopolysaccharide, polyhydroxyalkanoates, and osmoprotectants. The genomic information presented here will not only provide additional information to enhance our understanding of the genetic and metabolic network of halophilic bacteria, but also accelerate the research on systematical design of engineering strategies for biotechnology applications.

Microfluidics and nanoparticles based amperometric biosensor for the detection of cyanobacteria (Planktothrix agardhii NIVA-CYA 116) DNA.

Some of the cyanobacteria produce protease inhibitor oligopeptides such as cyanopeptolins and cause drinking water contamination; hence, their detection has great importance to monitor the well-being of water sources that is used for human consumption. In the current study, a fast and sensitive nucleic acid biosensor assay has been described where cyanopeptolin coding region of one of the cyanobacteria (Planktothrix agardhii NIVA-CYA 116) genome has been used as target for monitoring of the fresh water resources. A biochip that has two sets of Au electrode arrays, each consist of shared reference/counter electrodes and 3 working electrodes has been used for the assay. The biochip has been integrated to a microfluidics system and all steps of the assay have been performed during the reagent flow to achieve fast and sensitive DNA detection. On-line hybridization of the target on to the capture probe immobilized surface resulted in a very short assay duration with respect to the conventional static assays. The binding of the avidin and enzyme modified Au nanoparticles to the biotinylated detection probe and the subsequent injection of the substrate enabled a real-time amperometric measurement with a detection limit of 6×10(-12) M target DNA (calibration curve r(2)=0.98). The developed assay enables fast and sensitive detection of cyanopeptolin producing cyanobacteria from freshwater samples and hence shows a promising technology for toxic microorganism detection from environmental samples.