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1.  Taxonomically and functionally diverse microbial communities in deep crystalline rocks of the Fennoscandian shield 
The ISME Journal  2013;8(1):126-138.
Microbial life in the nutrient-limited and low-permeability continental crystalline crust is abundant but remains relatively unexplored. Using high-throughput sequencing to assess the 16S rRNA gene diversity, we found diverse bacterial and archaeal communities along a 2516-m-deep drill hole in continental crystalline crust in Outokumpu, Finland. These communities varied at different sampling depths in response to prevailing lithology and hydrogeochemistry. Further analysis by shotgun metagenomic sequencing revealed variable carbon and nutrient utilization strategies as well as specific functional and physiological adaptations uniquely associated with specific environmental conditions. Altogether, our results show that predominant geological and hydrogeochemical conditions, including the existence and connectivity of fracture systems and the low amounts of available energy, have a key role in controlling microbial ecology and evolution in the nutrient and energy-poor deep crustal biosphere.
PMCID: PMC3869007  PMID: 23949662
deep subsurface; crystalline rock; metagenomic sequencing; metabolism; bacteria; archaea
2.  Comparative genomics of Lactobacillus crispatus suggests novel mechanisms for the competitive exclusion of Gardnerella vaginalis 
BMC Genomics  2014;15(1):1070.
Lactobacillus crispatus is a ubiquitous micro-organism encountered in a wide range of host-associated habitats. It can be recovered from the gastrointestinal tract of animals and it is a common constituent of the vaginal microbiota of humans. Moreover, L. crispatus can contribute to the urogenital health of the host through competitive exclusion and the production of antimicrobial agents. In order to investigate the genetic diversity of this important urogenital species, we performed a comparative genomic analysis of L. crispatus.
Utilizing the completed genome sequence of a strain ST1 and the draft genome sequences of nine other L. crispatus isolates, we defined the scale and scope of the pan- and core genomic potential of L. crispatus. Our comparative analysis identified 1,224 and 2,705 ortholog groups present in all or only some of the ten strains, respectively. Based on mathematical modeling, sequencing of additional L. crispatus isolates would result in the identification of new genes and functions, whereas the conserved core of the ten strains was a good representation of the final L. crispatus core genome, estimated to level at about 1,116 ortholog groups. Importantly, the current core was observed to encode bacterial components potentially promoting urogenital health. Using antibody fragments specific for one of the conserved L. crispatus adhesins, we demonstrated that the L. crispatus core proteins have a potential to reduce the ability of Gardnerella vaginalis to adhere to epithelial cells. These findings thereby suggest that L. crispatus core proteins could protect the vagina from G. vaginalis and bacterial vaginosis.
Our pan-genome analysis provides insights into the intraspecific genome variability and the collective molecular mechanisms of the species L. crispatus. Using this approach, we described the differences and similarities between the genomes and identified features likely to be important for urogenital health. Notably, the conserved genetic backbone of L. crispatus accounted for close to 60% of the ortholog groups of an average L. crispatus strain and included factors for the competitive exclusion of G. vaginalis, providing an explanation on how this urogenital species could improve vaginal health.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-1070) contains supplementary material, which is available to authorized users.
PMCID: PMC4300991  PMID: 25480015
Comparative genomics; Lactobacillus crispatus; Pan-genome; Core genome; Normal flora; Bacterial vaginosis; Gardnerella vaginalis; Competitive exclusion
3.  Combining high-throughput sequencing with fruit body surveys reveals contrasting life-history strategies in fungi 
The ISME Journal  2013;7(9):1696-1709.
Before the recent revolution in molecular biology, field studies on fungal communities were mostly confined to fruit bodies, whereas mycelial interactions were studied in the laboratory. Here we combine high-throughput sequencing with a fruit body inventory to study simultaneously mycelial and fruit body occurrences in a community of fungi inhabiting dead wood of Norway spruce. We studied mycelial occurrence by extracting DNA from wood samples followed by 454-sequencing of the ITS1 and ITS2 regions and an automated procedure for species identification. In total, we detected 198 species as mycelia and 137 species as fruit bodies. The correlation between mycelial and fruit body occurrences was high for the majority of the species, suggesting that high-throughput sequencing can successfully characterize the dominating fungal communities, despite possible biases related to sampling, PCR, sequencing and molecular identification. We used the fruit body and molecular data to test hypothesized links between life history and population dynamic parameters. We show that the species that have on average a high mycelial abundance also have a high fruiting rate and produce large fruit bodies, leading to a positive feedback loop in their population dynamics. Earlier studies have shown that species with specialized resource requirements are rarely seen fruiting, for which reason they are often classified as red-listed. We show with the help of high-throughput sequencing that some of these species are more abundant as mycelium in wood than what could be expected from their occurrence as fruit bodies.
PMCID: PMC3749500  PMID: 23575372
454-sequencing; fruit body; population dynamics; molecular species identification; mycelia; wood-inhabiting fungi
4.  Transcriptome Analysis Reveals Signature of Adaptation to Landscape Fragmentation 
PLoS ONE  2014;9(7):e101467.
We characterize allelic and gene expression variation between populations of the Glanville fritillary butterfly (Melitaea cinxia) from two fragmented and two continuous landscapes in northern Europe. The populations exhibit significant differences in their life history traits, e.g. butterflies from fragmented landscapes have higher flight metabolic rate and dispersal rate in the field, and higher larval growth rate, than butterflies from continuous landscapes. In fragmented landscapes, local populations are small and have a high risk of local extinction, and hence the long-term persistence at the landscape level is based on frequent re-colonization of vacant habitat patches, which is predicted to select for increased dispersal rate. Using RNA-seq data and a common garden experiment, we found that a large number of genes (1,841) were differentially expressed between the landscape types. Hexamerin genes, the expression of which has previously been shown to have high heritability and which correlate strongly with larval development time in the Glanville fritillary, had higher expression in fragmented than continuous landscapes. Genes that were more highly expressed in butterflies from newly-established than old local populations within a fragmented landscape were also more highly expressed, at the landscape level, in fragmented than continuous landscapes. This result suggests that recurrent extinctions and re-colonizations in fragmented landscapes select a for specific expression profile. Genes that were significantly up-regulated following an experimental flight treatment had higher basal expression in fragmented landscapes, indicating that these butterflies are genetically primed for frequent flight. Active flight causes oxidative stress, but butterflies from fragmented landscapes were more tolerant of hypoxia. We conclude that differences in gene expression between the landscape types reflect genomic adaptations to landscape fragmentation.
PMCID: PMC4079591  PMID: 24988207
5.  Transcriptome dynamics-based operon prediction in prokaryotes 
BMC Bioinformatics  2014;15:145.
Inferring operon maps is crucial to understanding the regulatory networks of prokaryotic genomes. Recently, RNA-seq based transcriptome studies revealed that in many bacterial species the operon structure vary with the change of environmental conditions. Therefore, new computational solutions that use both static and dynamic data are necessary to create condition specific operon predictions.
In this work, we propose a novel classification method that integrates RNA-seq based transcriptome profiles with genomic sequence features to accurately identify the operons that are expressed under a measured condition. The classifiers are trained on a small set of confirmed operons and then used to classify the remaining gene pairs of the organism studied. Finally, by linking consecutive gene pairs classified as operons, our computational approach produces condition-dependent operon maps. We evaluated our approach on various RNA-seq expression profiles of the bacteria Haemophilus somni, Porphyromonas gingivalis, Escherichia coli and Salmonella enterica. Our results demonstrate that, using features depending on both transcriptome dynamics and genome sequence characteristics, we can identify operon pairs with high accuracy. Moreover, the combination of DNA sequence and expression data results in more accurate predictions than each one alone.
We present a computational strategy for the comprehensive analysis of condition-dependent operon maps in prokaryotes. Our method can be used to generate condition specific operon maps of many bacterial organisms for which high-resolution transcriptome data is available.
PMCID: PMC4235196  PMID: 24884724
Operons; Computational prediction; Condition-dependent operon maps; RNA-seq data analysis
6.  Correction: Lack of RsmA-Mediated Control Results in Constant Hypervirulence, Cell Elongation, and Hyperflagellation in Pectobacterium wasabiae 
PLoS ONE  2013;8(12):10.1371/annotation/6bc0b20b-3736-431f-9687-67986101128f.
PMCID: PMC3865326
7.  Correction: Gene Expression Profiles in Human and Mouse Primary Cells Provide New Insights into the Differential Actions of Vitamin D3 Metabolites 
PLoS ONE  2013;8(11):10.1371/annotation/9cb2000b-a962-453c-ad8b-088f91095f6d.
PMCID: PMC3838210
8.  Gene Expression Profiles in Human and Mouse Primary Cells Provide New Insights into the Differential Actions of Vitamin D3 Metabolites 
PLoS ONE  2013;8(10):e75338.
1α,25-Dihydroxyvitamin D3 (1α,25(OH)2D3) had earlier been regarded as the only active hormone. The newly identified actions of 25-hydroxyvitamin D3 (25(OH)D3) and 24R,25-dihydroxyvitamin D3 (24R,25(OH)2D3) broadened the vitamin D3 endocrine system, however, the current data are fragmented and a systematic understanding is lacking. Here we performed the first systematic study of global gene expression to clarify their similarities and differences. Three metabolites at physiologically comparable levels were utilized to treat human and mouse fibroblasts prior to DNA microarray analyses. Human primary prostate stromal P29SN cells (hP29SN), which convert 25(OH)D3 into 1α,25(OH)2D3 by 1α-hydroxylase (encoded by the gene CYP27B1), displayed regulation of 164, 171, and 175 genes by treatment with 1α,25(OH)2D3, 25(OH)D3, and 24R,25(OH)2D3, respectively. Mouse primary Cyp27b1 knockout fibroblasts (mCyp27b1−/−), which lack 1α-hydroxylation, displayed regulation of 619, 469, and 66 genes using the same respective treatments. The number of shared genes regulated by two metabolites is much lower in hP29SN than in mCyp27b1−/−. By using DAVID Functional Annotation Bioinformatics Microarray Analysis tools and Ingenuity Pathways Analysis, we identified the agonistic regulation of calcium homeostasis and bone remodeling between 1α,25(OH)2D3 and 25(OH)D3 and unique non-classical actions of each metabolite in physiological and pathological processes, including cell cycle, keratinocyte differentiation, amyotrophic lateral sclerosis signaling, gene transcription, immunomodulation, epigenetics, cell differentiation, and membrane protein expression. In conclusion, there are three distinct vitamin D3 hormones with clearly different biological activities. This study presents a new conceptual insight into the vitamin D3 endocrine system, which may guide the strategic use of vitamin D3 in disease prevention and treatment.
PMCID: PMC3792969  PMID: 24116037
9.  Role and Regulation of the Flp/Tad Pilus in the Virulence of Pectobacterium atrosepticum SCRI1043 and Pectobacterium wasabiae SCC3193 
PLoS ONE  2013;8(9):e73718.
In this study, we characterized a putative Flp/Tad pilus-encoding gene cluster, and we examined its regulation at the transcriptional level and its role in the virulence of potato pathogenic enterobacteria of the genus Pectobacterium. The Flp/Tad pilus-encoding gene clusters in Pectobacterium atrosepticum, Pectobacterium wasabiae and Pectobacterium aroidearum were compared to previously characterized flp/tad gene clusters, including that of the well-studied Flp/Tad pilus model organism Aggregatibacter actinomycetemcomitans, in which this pilus is a major virulence determinant. Comparative analyses revealed substantial protein sequence similarity and open reading frame synteny between the previously characterized flp/tad gene clusters and the cluster in Pectobacterium, suggesting that the predicted flp/tad gene cluster in Pectobacterium encodes a Flp/Tad pilus-like structure. We detected genes for a novel two-component system adjacent to the flp/tad gene cluster in Pectobacterium, and mutant analysis demonstrated that this system has a positive effect on the transcription of selected Flp/Tad pilus biogenesis genes, suggesting that this response regulator regulate the flp/tad gene cluster. Mutagenesis of either the predicted regulator gene or selected Flp/Tad pilus biogenesis genes had a significant impact on the maceration ability of the bacterial strains in potato tubers, indicating that the Flp/Tad pilus-encoding gene cluster represents a novel virulence determinant in Pectobacterium. Soft-rot enterobacteria in the genera Pectobacterium and Dickeya are of great agricultural importance, and an investigation of the virulence of these pathogens could facilitate improvements in agricultural practices, thus benefiting farmers, the potato industry and consumers.
PMCID: PMC3767616  PMID: 24040039
10.  Significance of Heme-Based Respiration in Meat Spoilage Caused by Leuconostoc gasicomitatum 
Leuconostoc gasicomitatum is a psychrotrophic lactic acid bacterium (LAB) which causes spoilage in cold-stored modified-atmosphere-packaged (MAP) meat products. In addition to the fermentative metabolism, L. gasicomitatum is able to respire when exogenous heme and oxygen are available. In this study, we investigated the respiration effects on growth rate, biomass, gene expression, and volatile organic compound (VOC) production in laboratory media and pork loin. The meat samples were evaluated by a sensory panel every second or third day for 29 days. We observed that functional respiration increased the growth (rate and yield) of L. gasicomitatum in laboratory media with added heme and in situ meat with endogenous heme. Respiration increased enormously (up to 2,600-fold) the accumulation of acetoin and diacetyl, which are buttery off-odor compounds in meat. Our transcriptome analyses showed that the gene expression patterns were quite similar, irrespective of whether respiration was turned off by excluding heme from the medium or mutating the cydB gene, which is essential in the respiratory chain. The respiration-based growth of L. gasicomitatum in meat was obtained in terms of population development and subsequent development of sensory characteristics. Respiration is thus a key factor explaining why L. gasicomitatum is so well adapted in high-oxygen packed meat.
PMCID: PMC3568588  PMID: 23204416
11.  Identification and Validation of Human Papillomavirus Encoded microRNAs 
PLoS ONE  2013;8(7):e70202.
We report here identification and validation of the first papillomavirus encoded microRNAs expressed in human cervical lesions and cell lines. We established small RNA libraries from ten human papillomavirus associated cervical lesions including cancer and two human papillomavirus harboring cell lines. These libraries were sequenced using SOLiD 4 technology. We used the sequencing data to predict putative viral microRNAs and discovered nine putative papillomavirus encoded microRNAs. Validation was performed for five candidates, four of which were successfully validated by qPCR from cervical tissue samples and cell lines: two were encoded by HPV 16, one by HPV 38 and one by HPV 68. The expression of HPV 16 microRNAs was further confirmed by in situ hybridization, and colocalization with p16INK4A was established. Prediction of cellular target genes of HPV 16 encoded microRNAs suggests that they may play a role in cell cycle, immune functions, cell adhesion and migration, development, and cancer. Two putative viral target sites for the two validated HPV 16 miRNAs were mapped to the E5 gene, one in the E1 gene, two in the L1 gene and one in the LCR region. This is the first report to show that papillomaviruses encode their own microRNA species. Importantly, microRNAs were found in libraries established from human cervical disease and carcinoma cell lines, and their expression was confirmed in additional tissue samples. To our knowledge, this is also the first paper to use in situ hybridization to show the expression of a viral microRNA in human tissue.
PMCID: PMC3728184  PMID: 23936163
12.  Gene Expression Patterns Underlying the Reinstatement of Plasticity in the Adult Visual System 
Neural Plasticity  2013;2013:605079.
The nervous system is highly sensitive to experience during early postnatal life, but this phase of heightened plasticity decreases with age. Recent studies have demonstrated that developmental-like plasticity can be reactivated in the visual cortex of adult animals through environmental or pharmacological manipulations. These findings provide a unique opportunity to study the cellular and molecular mechanisms of adult plasticity. Here we used the monocular deprivation paradigm to investigate large-scale gene expression patterns underlying the reinstatement of plasticity produced by fluoxetine in the adult rat visual cortex. We found changes, confirmed with RT-PCRs, in gene expression in different biological themes, such as chromatin structure remodelling, transcription factors, molecules involved in synaptic plasticity, extracellular matrix, and excitatory and inhibitory neurotransmission. Our findings reveal a key role for several molecules such as the metalloproteases Mmp2 and Mmp9 or the glycoprotein Reelin and open up new insights into the mechanisms underlying the reopening of the critical periods in the adult brain.
PMCID: PMC3710606  PMID: 23936678
14.  Genome Sequence of Pectobacterium sp. Strain SCC3193 
Journal of Bacteriology  2012;194(21):6004.
We report the complete and annotated genome sequence of the plant-pathogenic enterobacterium Pectobacterium sp. strain SCC3193, a model strain isolated from potato in Finland. The Pectobacterium sp. SCC3193 genome consists of a 516,411-bp chromosome, with no plasmids.
PMCID: PMC3486080  PMID: 23045508
15.  Mondo/ChREBP-Mlx-Regulated Transcriptional Network Is Essential for Dietary Sugar Tolerance in Drosophila 
PLoS Genetics  2013;9(4):e1003438.
Sugars are important nutrients for many animals, but are also proposed to contribute to overnutrition-derived metabolic diseases in humans. Understanding the genetic factors governing dietary sugar tolerance therefore has profound biological and medical significance. Paralogous Mondo transcription factors ChREBP and MondoA, with their common binding partner Mlx, are key sensors of intracellular glucose flux in mammals. Here we report analysis of the in vivo function of Drosophila melanogaster Mlx and its binding partner Mondo (ChREBP) in respect to tolerance to dietary sugars. Larvae lacking mlx or having reduced mondo expression show strikingly reduced survival on a diet with moderate or high levels of sucrose, glucose, and fructose. mlx null mutants display widespread changes in lipid and phospholipid profiles, signs of amino acid catabolism, as well as strongly elevated circulating glucose levels. Systematic loss-of-function analysis of Mlx target genes reveals that circulating glucose levels and dietary sugar tolerance can be genetically uncoupled: Krüppel-like transcription factor Cabut and carbonyl detoxifying enzyme Aldehyde dehydrogenase type III are essential for dietary sugar tolerance, but display no influence on circulating glucose levels. On the other hand, Phosphofructokinase 2, a regulator of the glycolysis pathway, is needed for both dietary sugar tolerance and maintenance of circulating glucose homeostasis. Furthermore, we show evidence that fatty acid synthesis, which is a highly conserved Mondo-Mlx-regulated process, does not promote dietary sugar tolerance. In contrast, survival of larvae with reduced fatty acid synthase expression is sugar-dependent. Our data demonstrate that the transcriptional network regulated by Mondo-Mlx is a critical determinant of the healthful dietary spectrum allowing Drosophila to exploit sugar-rich nutrient sources.
Author Summary
Diet displays extreme natural variation between animal species, which range from highly specialized carnivores, herbivores, and nectarivores to flexible dietary generalists. Humans are not identical in this respect either, but the genetic background likely defines the framework for a healthy diet. However, we understand poorly the genetic factors that define the spectrum of healthy diet for a given species or individual. Here we have explored the genetic basis of dietary sugar tolerance of Drosophila melanogaster. D. melanogaster is a generalist fruit breeder that feeds on micro-organisms on decaying fruits and vegetables with varying sugar content. However, mutants lacking the conserved Mondo-Mlx transcription factor complex display striking intolerance towards dietary sucrose, glucose, or fructose. This is manifested in the larvae by the inability to grow and pupate on sugar-rich food, including red grape, which belongs to the normal diet of wild D. melanogaster. Larvae lacking Mondo-Mlx show widespread metabolic imbalance, including highly elevated circulating glucose. Genome-wide gene expression analysis combined with systematic loss-of-function screening of Mlx targets reveal that the genetic network providing sugar tolerance includes a secondary transcriptional effector as well as regulators of glycolysis and detoxification of reactive metabolites.
PMCID: PMC3616910  PMID: 23593032
16.  Lack of RsmA-Mediated Control Results in Constant Hypervirulence, Cell Elongation, and Hyperflagellation in Pectobacterium wasabiae 
PLoS ONE  2013;8(1):e54248.
The posttranscriptional regulator RsmA controls the production of plant cell wall degrading enzymes (PCWDE) and cell motility in the Pectobacterium genus of plant pathogens. In this study the physiological role of gene regulation by RsmA is under investigation. Disruption of rsmA gene of the Pectobacterium wasabiae strain, SCC3193 resulted in 3-fold decrease in growth rate and increased virulence. The comparison of mRNA levels of the rsmA− mutant and wild-type using a genome-wide microarray showed, that genes responsible for successful infection, i.e. virulence factors, motility, butanediol fermentation, various secretion systems etc. were up-regulated in the rsmA− strain. The rsmA− strain exhibited a higher propensity to swarm and produce PCWDE compared to the wild-type strain. Virulence experiments in potato tubers demonstrated that in spite of its more efficient tissue maceration, the rsmA− strain's ability to survive within the host is reduced and the infection site is taken over by resident bacteria. Taken together, in the absence of RsmA, cells revert to a constitutively infective phenotype characterized by expression of virulence factors and swarming. We hypothesize that lack of control over these costly energetic processes results in decreased growth rate and fitness. In addition, our findings suggest a relationship between swarming and virulence in plant pathogens.
PMCID: PMC3553148  PMID: 23372695
17.  SNP Design from 454 Sequencing of Podosphaera plantaginis Transcriptome Reveals a Genetically Diverse Pathogen Metapopulation with High Levels of Mixed-Genotype Infection 
PLoS ONE  2012;7(12):e52492.
Molecular tools may greatly improve our understanding of pathogen evolution and epidemiology but technical constraints have hindered the development of genetic resources for parasites compared to free-living organisms. This study aims at developing molecular tools for Podosphaera plantaginis, an obligate fungal pathogen of Plantago lanceolata. This interaction has been intensively studied in the Åland archipelago of Finland with epidemiological data collected from over 4,000 host populations annually since year 2001.
Principal Findings
A cDNA library of a pooled sample of fungal conidia was sequenced on the 454 GS-FLX platform. Over 549,411 reads were obtained and annotated into 45,245 contigs. Annotation data was acquired for 65.2% of the assembled sequences. The transcriptome assembly was screened for SNP loci, as well as for functionally important genes (mating-type genes and potential effector proteins). A genotyping assay of 27 SNP loci was designed and tested on 380 infected leaf samples from 80 populations within the Åland archipelago. With this panel we identified 85 multilocus genotypes (MLG) with uneven frequencies across the pathogen metapopulation. Approximately half of the sampled populations contain polymorphism. Our genotyping protocol revealed mixed-genotype infection within a single host leaf to be common. Mixed infection has been proposed as one of the main drivers of pathogen evolution, and hence may be an important process in this pathosystem.
The developed SNP panel offers exciting research perspectives for future studies in this well-characterized pathosystem. Also, the transcriptome provides an invaluable novel genomic resource for powdery mildews, which cause significant yield losses on commercially important crops annually. Furthermore, the features that render genetic studies in this system a challenge are shared with the majority of obligate parasitic species, and hence our results provide methodological insights from SNP calling to field sampling protocols for a wide range of biological systems.
PMCID: PMC3531457  PMID: 23300684
18.  Identification and Characterization of a Lipopolysaccharide α,2,3-Sialyltransferase from the Human Pathogen Helicobacter bizzozeronii 
Journal of Bacteriology  2012;194(10):2540-2550.
Terminal sialic acid in the lipopolysaccharides (LPSs) of mucosal pathogens is an important virulence factor. Here we report the characterization of a Helicobacter sialyltransferase involved in the biosynthesis of sialylated LPS in Helicobacter bizzozeronii, the only non-pylori gastric Helicobacter species isolated from humans thus far. Starting from the genome sequences of canine and human strains, we identified potential sialyltransferases downstream of three genes involved in the biosynthesis of N-acetylneuraminic acid. One of these candidates showed monofunctional α,2,3-sialyltransferase activity with a preference for N-acetyllactosamine as a substrate. The LPSs from different strains were shown by SDS-PAGE and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) to contain sialic acid after neuraminidase treatment. The expression of this sialyltransferase and sialyl-LPS appeared to be a phase-variable characteristic common to both human and canine H. bizzozeronii strains. The sialylation site of the LPSs of two H. bizzozeronii strains was determined to be NeuAc-Hex-HexNAc, suggesting terminal 3′-sialyl-LacNAc. Moreover, serological typing revealed the possible presence of sialyl-Lewis X in two additional strains, indicating that H. bizzozeronii could also mimic the surface glycans of mammalian cells. The expression of sialyl-glycans may influence the adaptation process of H. bizzozeronii during the host jump from dogs to humans.
PMCID: PMC3347187  PMID: 22408169
19.  Cell culture model predicts human disease: Altered expression of junction proteins and matrix metalloproteinases in cervical dysplasia 
Cervical cancer is necessarily caused by human papillomaviruses, which encode three oncogenes manifesting their functions by interfering with a number of cellular proteins and pathways: the E5, E6, and E7 proteins. We have earlier found in our microarray studies that the E5 oncogene crucially affects the expression of cellular genes involved in adhesion and motility of epithelial cells.
In order to biologically validate our previous experimental findings we performed immunohistochemical staining of a representative set of tissue samples from different grades of high-risk human papillomavirus associated cervical disease as well as normal squamous and columnar cervical epithelium. Three-dimensional collagen raft cultures established from E5-expressing and control epithelial cells were also examined. The expression of p16, matrix metalloproteinase (MMP) -7, MMP-16, cytokeratin (CK) 8/18, laminin, E-cadherin and beta-catenin was studied.
In agreement with our previous microarray studies, we found intense staining for E-cadherin and beta-catenin in adherens junctions even in high-grade cervical lesions. Staining for MMP-16 was increased in severe disease as well. No significant change in staining for MMP-7 and cytokeratin 8/18 along with the grade of cervical squamous epithelial disease was observed.
Here we have confirmed, using tissue material from human papillomavirus associated lesions, some of the cellular gene expression modifications that we earlier reported in an experimental system studying specifically the E5 oncogene of papillomaviruses. These findings were partially surprising in the context of cervical carcinogenesis and emphasize that the complexity of carcinogenesis is not yet fully understood. Microarray approaches provide a wide overwiev of gene expression in experimental settings, which may yield biologically valid biomarkers for disease diagnostics, prognosis, and follow-up.
PMCID: PMC3495715  PMID: 22863036
Cadherin; Catenin; CIN; Cytokeratin; E5; HPV; Microarray; MMP
20.  Comparison of Dorsocervical With Abdominal Subcutaneous Adipose Tissue in Patients With and Without Antiretroviral Therapy–Associated Lipodystrophy 
Diabetes  2011;60(7):1894-1900.
Combination antiretroviral therapy (cART) is associated with lipodystrophy, i.e., loss of subcutaneous adipose tissue in the abdomen, limbs, and face and its accumulation intra-abdominally. No fat is lost dorsocervically and it can even accumulate in this region (buffalo hump). It is unknown how preserved dorsocervical fat differs from abdominal subcutaneous fat in HIV-1–infected cART-treated patients with (cART+LD+) and without (cART+LD−) lipodystrophy.
We used histology, microarray, PCR, and magnetic resonance imaging to compare dorsocervical and abdominal subcutaneous adipose tissue in cART+LD+ (n = 21) and cART+LD− (n = 11).
Albeit dorsocervical adipose tissue in cART+LD+ seems spared from lipoatrophy, its mitochondrial DNA (mtDNA; copies/cell) content was significantly lower (by 62%) than that of the corresponding tissue in cART+LD−. Expression of CD68 mRNA, a marker of macrophages, and numerous inflammatory genes in microarray were significantly lower in dorsocervical versus abdominal subcutaneous adipose tissue. Genes with the greatest difference in expression between the two depots were those involved in regulation of transcription and regionalization (homeobox genes), irrespective of lipodystrophy status. There was negligible mRNA expression of uncoupling protein 1, a gene characteristic of brown adipose tissue, in either depot.
Because mtDNA is depleted even in the nonatrophic dorsocervical adipose tissue, it is unlikely that the cause of lipoatrophy is loss of mtDNA. Dorsocervical adipose tissue is less inflamed than lipoatrophic adipose tissue. It does not resemble brown adipose tissue. The greatest difference in gene expression between dorsocervical and abdominal subcutaneous adipose tissue is in expression of homeobox genes.
PMCID: PMC3121420  PMID: 21602514
21.  Molecular analysis of meso- and thermophilic microbiota associated with anaerobic biowaste degradation 
BMC Microbiology  2012;12:121.
Microbial anaerobic digestion (AD) is used as a waste treatment process to degrade complex organic compounds into methane. The archaeal and bacterial taxa involved in AD are well known, whereas composition of the fungal community in the process has been less studied. The present study aimed to reveal the composition of archaeal, bacterial and fungal communities in response to increasing organic loading in mesophilic and thermophilic AD processes by applying 454 amplicon sequencing technology. Furthermore, a DNA microarray method was evaluated in order to develop a tool for monitoring the microbiological status of AD.
The 454 sequencing showed that the diversity and number of bacterial taxa decreased with increasing organic load, while archaeal i.e. methanogenic taxa remained more constant. The number and diversity of fungal taxa increased during the process and varied less in composition with process temperature than bacterial and archaeal taxa, even though the fungal diversity increased with temperature as well. Evaluation of the microarray using AD sample DNA showed correlation of signal intensities with sequence read numbers of corresponding target groups. The sensitivity of the test was found to be about 1%.
The fungal community survives in anoxic conditions and grows with increasing organic loading, suggesting that Fungi may contribute to the digestion by metabolising organic nutrients for bacterial and methanogenic groups. The microarray proof of principle tests suggest that the method has the potential for semiquantitative detection of target microbial groups given that comprehensive sequence data is available for probe design.
PMCID: PMC3408363  PMID: 22727142
22.  Gene expression analysis of Drosophilaa Manf mutants reveals perturbations in membrane traffic and major metabolic changes 
BMC Genomics  2012;13:134.
MANF and CDNF are evolutionarily conserved neurotrophic factors that specifically support dopaminergic neurons. To date, the receptors and signalling pathways of this novel MANF/CDNF family have remained unknown. Independent studies have showed upregulation of MANF by unfolded protein response (UPR). To enlighten the role of MANF in multicellular organism development we carried out a microarray-based analysis of the transcriptional changes induced by the loss and overexpression of Drosophila Manf.
The most dramatic change of expression was observed with genes coding membrane transport proteins and genes related to metabolism. When evaluating in parallel the ultrastructural data and transcriptome changes of maternal/zygotic and only zygotic Manf mutants, the endoplasmic reticulum (ER) stress and membrane traffic alterations were evident. In Drosophila Manf mutants the expression of several genes involved in Parkinson's disease (PD) was altered as well.
We conclude that besides a neurotrophic factor, Manf is an important cellular survival factor needed to overcome the UPR especially in tissues with high secretory function. In the absence of Manf, the expression of genes involved in membrane transport, particularly exocytosis and endosomal recycling pathway was altered. In neurodegenerative diseases, such as PD, correct protein folding and proteasome function as well as neurotransmitter synthesis and uptake are crucial for the survival of neurons. The degeneration of dopaminergic neurons is the hallmark for PD and our work provides a clue on the mechanisms by which the novel neurotrophic factor MANF protects these neurons.
PMCID: PMC3364883  PMID: 22494833
23.  Detection of Human Papillomaviruses by Polymerase Chain Reaction and Ligation Reaction on Universal Microarray 
PLoS ONE  2012;7(3):e34211.
Sensitive and specific detection of human papillomaviruses (HPV) in cervical samples is a useful tool for the early diagnosis of epithelial neoplasia and anogenital lesions. Recent studies support the feasibility of HPV DNA testing instead of cytology (Pap smear) as a primary test in population screening for cervical cancer. This is likely to be an option in the near future in many countries, and it would increase the efficiency of screening for cervical abnormalities. We present here a microarray test for the detection and typing of 15 most important high-risk HPV types and two low risk types. The method is based on type specific multiplex PCR amplification of the L1 viral genomic region followed by ligation detection reaction where two specific ssDNA probes, one containing a fluorescent label and the other a flanking ZipCode sequence, are joined by enzymatic ligation in the presence of the correct HPV PCR product. Human beta-globin is amplified in the same reaction to control for sample quality and adequacy. The genotyping capacity of our approach was evaluated against Linear Array test using cervical samples collected in transport medium. Altogether 14 out of 15 valid samples (93%) gave concordant results between our test and Linear Array. One sample was HPV56 positive in our test and high-risk positive in Hybrid Capture 2 but remained negative in Linear Array. The preliminary results suggest that our test has accurate multiple HPV genotyping capability with the additional advantages of generic detection format, and potential for high-throughput screening.
PMCID: PMC3311614  PMID: 22457826
24.  Genome Sequence of a Food Spoilage Lactic Acid Bacterium, Leuconostoc gasicomitatum LMG 18811T, in Association with Specific Spoilage Reactions ▿ †  
Applied and Environmental Microbiology  2011;77(13):4344-4351.
Leuconostoc gasicomitatum is a psychrotrophic lactic acid bacterium causing spoilage of cold-stored, modified-atmosphere-packaged (MAP), nutrient-rich foods. Its role has been verified by challenge tests in gas and slime formation, development of pungent acidic and buttery off odors, and greening of beef. MAP meats have especially been prone to L. gasicomitatum spoilage. In addition, spoilage of vacuum-packaged vegetable sausages and marinated herring has been reported. The genomic sequencing project of L. gasicomitatum LMG 18811T was prompted by a need to understand the growth and spoilage potentials of L. gasicomitatum, to study its phylogeny, and to be able to knock out and overexpress the genes. Comparative genomic analysis was done within L. gasicomitatum LMG 18811T and the three fully assembled Leuconostoc genomes (those of Leuconostoc mesenteroides, Leuconostoc citreum, and Leuconostoc kimchii) available. The genome of L. gasicomitatum LMG 18811T is plasmid-free and contains a 1,954,080-bp circular chromosome with an average GC content of 36.7%. It includes genes for the phosphoketolase pathway and alternative pathways for pyruvate utilization. As interesting features associated with the growth and spoilage potential, LMG 18811T possesses utilization strategies for ribose, external nucleotides, nucleosides, and nucleobases and it has a functional electron transport chain requiring only externally supplied heme for respiration. In respect of the documented specific spoilage reactions, the pathways/genes associated with a buttery off odor, meat greening, and slime formation were recognized. Unexpectedly, genes associated with platelet binding and collagen adhesion were detected, but their functionality and role in food spoilage and processing environment contamination need further study.
PMCID: PMC3127722  PMID: 21571876
25.  Growth phase‐associated changes in the proteome and transcriptome of Lactobacillus rhamnosus GG in industrial‐type whey medium 
Microbial biotechnology  2011;4(6):746-766.
The growth phase during which probiotic bacteria are harvested and consumed can strongly influence their performance as health‐promoting agents. In this study, global transcriptomic and proteomic changes were studied in the widely used probiotic Lactobacillus rhamnosus GG during growth in industrial‐type whey medium under strictly defined bioreactor conditions. The expression of 636 genes (P ≤ 0.01) and 116 proteins (P < 0.05) changed significantly over time. Of the significantly differentially produced proteins, 61 were associated with alterations at the transcript level. The most remarkable growth phase‐dependent changes occurred during the transition from the exponential to the stationary growth phase and were associated with the shift from glucose fermentation to galactose utilization and the transition from homolactic to mixed acid fermentation. Furthermore, several genes encoding proteins proposed to promote the survival and persistence of L. rhamnosus GG in the host and proteins that directly contribute to human health showed temporal changes in expression. Our results suggest that L. rhamnosus GG has a highly flexible and adaptable metabolism and that the growth stage during which bacterial cells are harvested and consumed should be taken into consideration to gain the maximal benefit from probiotic bacteria.
PMCID: PMC3815411  PMID: 21883975

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