A history of repeated antibiotic usage leads to microbiota-dependent mucus defects.

Recent evidence indicates that repeated antibiotic usage lowers microbial diversity and ultimately changes the gut microbiota community. However, the physiological effects of repeated - but not recent - antibiotic usage on microbiota-mediated mucosal barrier function are largely unknown. By selecting human individuals from the deeply phenotyped Estonian Microbiome Cohort (EstMB), we here utilized human-to-mouse fecal microbiota transplantation to explore long-term impacts of repeated antibiotic use on intestinal mucus function.

Gut microbiome in endometriosis: a cohort study on 1000 individuals.

Background: Endometriosis, defined as the presence of endometrial-like tissue outside of the uterus, is one of the most prevalent gynecological disorders. Although different theories have been proposed, its pathogenesis is not clear. Novel studies indicate that the gut microbiome may be involved in the etiology of endometriosis; nevertheless, the connection between microbes, their dysbiosis, and the development of endometriosis is understudied.

The landscape of autosomal-recessive pathogenic variants in European populations reveals phenotype-specific effects.

The number and distribution of recessive alleles in the population for various diseases are not known at genome-wide-scale. Based on 6,447 exome sequences of healthy, genetically unrelated Europeans of two distinct ancestries, we estimate that every individual is a carrier of at least 2 pathogenic variants in currently known autosomal-recessive (AR) genes and that 0.8%-1% of European couples are at risk of having a child affected with a severe AR genetic disorder.

Genome-wide histone modification profiling of inner cell mass and trophectoderm of bovine blastocysts by RAT-ChIP.

Chromatin immunoprecipitation coupled with next-generation sequencing (ChIP-seq) has revolutionized our understanding of chromatin-related biological processes. The method, however, requires thousands of cells and has therefore limited applications in situations where cell numbers are limited. Here we describe a novel method called Restriction Assisted Tagmentation Chromatin Immunoprecipitation (RAT-ChIP) that enables global histone modification profiling from as few as 100 cells.

Primer3_masker: integrating masking of template sequence with primer design software.

Summary: Designing PCR primers for amplifying regions of eukaryotic genomes is a complicated task because the genomes contain a large number of repeat sequences and other regions unsuitable for amplification by PCR. We have developed a novel k-mer based masking method that uses a statistical model to detect and mask failure-prone regions on the DNA template prior to primer design. We implemented the software as a standalone software primer3_masker and integrated it into the primer design program Primer3.

StrainSeeker: fast identification of bacterial strains from raw sequencing reads using user-provided guide trees.

Background: Fast, accurate and high-throughput identification of bacterial isolates is in great demand. The present work was conducted to investigate the possibility of identifying isolates from unassembled next-generation sequencing reads using custom-made guide trees.

Results: A tool named StrainSeeker was developed that constructs a list of specific -mers for each node of any given Newick-format tree and enables the identification of bacterial isolates in 1-2 min.

Fast masking of repeated primer binding sites in eukaryotic genomes.

In this article we describe the working principle and a list of practical applications for GenomeMasker-a program that finds and masks all repeated DNA motifs in fully sequenced genomes. The GenomeMasker exhaustively finds and masks all repeated DNA motifs in studied genomes. The software is optimized for PCR primer design.

Profile of whole blood gene expression following immune stimulation in a wild passerine.

Background: Immunoecology aims to explain variation among hosts in the strength and efficacy of immunological defences in natural populations. This requires development of biomarkers of the activation of the immune system so that they can be collected non-lethally and sampled from small amounts of easily obtainable tissue. We used transcriptome profiling in wild greenfinches (Carduelis chloris) to detect whole blood transcripts that most profoundly indicate upregulation of antimicrobial defences during acute phase response.

Genome and low-iron response of an oceanic diatom adapted to chronic iron limitation.

Background: Biogeochemical elemental cycling is driven by primary production of biomass via phototrophic phytoplankton growth, with 40% of marine productivity being assigned to diatoms. Phytoplankton growth is widely limited by the availability of iron, an essential component of the photosynthetic apparatus. The oceanic diatom Thalassiosira oceanica shows a remarkable tolerance to low-iron conditions and was chosen as a model for deciphering the cellular response upon shortage of this essential micronutrient.

Molecular diagnosis of Down syndrome using quantitative APEX-2 microarrays.

Objective: To develop a new rapid and high-throughput microarray-based prenatal diagnostic test for the detection of trisomy 21 (T21).

Methods: The T21 arrayed primer extension-2 (APEX-2) assay discriminates between trisomy and euploid DNA samples by comparing the signal intensities of allelic fractions of heterozygous single nucleotide polymorphisms (SNPs) after APEX reaction. After preliminary validation using DNA samples from Down syndrome patients, we analyzed DNA samples from cultured and uncultured amniocytes and chorionic villus for 90 SNPs with high heterozygosity from the 21(q21.

AIRE activated tissue specific genes have histone modifications associated with inactive chromatin.

The Autoimmune Regulator (AIRE) protein is expressed in thymic medullary epithelial cells, where it promotes the ectopic expression of tissue-restricted antigens needed for efficient negative selection of developing thymocytes. Mutations in AIRE cause APECED syndrome, which is characterized by a breakdown of self-tolerance. The molecular mechanism by which AIRE increases the expression of a variety of different genes remains unknown.

Development of a single tube 640-plex genotyping method for detection of nucleic acid variations on microarrays.

Detection of DNA sequence variation is critical to biomedical applications, including disease genetic identification, diagnosis and treatment, drug discovery and forensic analysis. Here, we describe an arrayed primer extension-based genotyping method (APEX-2) that allows multiplex (640-plex) DNA amplification and detection of single nucleotide polymorphisms (SNPs) and mutations on microarrays via four-color single-base primer extension. The founding principle of APEX-2 multiplex PCR requires two oligonucleotides per SNP/mutation to generate amplicons containing the position of interest.

Predicting failure rate of PCR in large genomes.

We have developed statistical models for estimating the failure rate of polymerase chain reaction (PCR) primers using 236 primer sequence-related factors. The model involved 1314 primer pairs and is based on more than 80 000 PCR experiments. We found that the most important factor in determining PCR failure is the number of predicted primer-binding sites in the genomic DNA.

Fast masking of repeated primer binding sites in eukaryotic genomes.

In this article, we describe the working principle and a list of practical applications for GenomeMasker-a program that finds and masks all repeated DNA motifs in fully sequenced genomes. The GenomeMasker exhaustively finds and masks all repeated DNA motifs in studied genomes. The software is optimized for polymerase chain reaction (PCR) primer design.

SNPmasker: automatic masking of SNPs and repeats across eukaryotic genomes.

SNPmasker is a comprehensive web interface for masking large eukaryotic genomes. The program is designed to mask SNPs from recent dbSNP database and to mask the repeats with two alternative programs. In addition to the SNP masking, we also offer population-specific substitution of SNP alleles in genomic sequence according to SNP frequencies in HapMap Phase II data.

GENOMEMASKER package for designing unique genomic PCR primers.

Background: The design of oligonucleotides and PCR primers for studying large genomes is complicated by the redundancy of sequences. The eukaryotic genomes are particularly difficult to study due to abundant repeats. The speed of most existing primer evaluation programs is not sufficient for large-scale experiments.

MultiPLX: automatic grouping and evaluation of PCR primers.

Unlabelled: MultiPLX is a new program for automatic grouping of PCR primers. It can use many different parameters to estimate the compatibility of primers, such as primer-primer interactions, primer-product interactions, difference in melting temperatures, difference in product length and the risk of generating alternative products from the template. A unique feature of the MultiPLX is the ability to perform automatic grouping of large number (thousands) of primer pairs.