Accurate Profiling of Microbial Communities from Massively Parallel Sequencing using Convex Optimization

We describe the Microbial Community Reconstruction ({\bf MCR}) Problem, which is fundamental for microbiome analysis. In this problem, the goal is to reconstruct the identity and frequency of species comprising a microbial community, using short sequence reads from Massively Parallel Sequencing (MPS) data obtained for specified genomic regions. We formulate the problem mathematically as a convex optimization problem and provide sufficient conditions for identifiability, namely the ability to reconstruct species identity and frequency correctly when the data size (number of reads) grows to infinity. We discuss different metrics for assessing the quality of the reconstructed solution, including a novel phylogenetically-aware metric based on the Mahalanobis distance, and give upper-bounds on the reconstruction error for a finite number of reads under different metrics. We propose a scalable divide-and-conquer algorithm for the problem using convex optimization, which enables us to handle large problems (with $\sim10^6$ species). We show using numerical simulations that for realistic scenarios, where the microbial communities are sparse, our algorithm gives solutions with high accuracy, both in terms of obtaining accurate frequency, and in terms of species phylogenetic resolution.Comment: To appear in SPIRE 1

The diacylglycerol kinase α/Atypical PKC/β1 integrin pathway in SDF-1α mammary carcinoma invasiveness

Diacylglycerol kinase α (DGKα), by phosphorylating diacylglycerol into phosphatidic acid, provides a key signal driving cell migration and matrix invasion. We previously demonstrated that in epithelial cells activation of DGKα activity promotes cytoskeletal remodeling and matrix invasion by recruiting atypical PKC at ruffling sites and by promoting RCP-mediated recycling of α5β1 integrin to the tip of pseudopods. In here we investigate the signaling pathway by which DGKα mediates SDF-1α-induced matrix invasion of MDA-MB-231 invasive breast carcinoma cells. Indeed we showed that, following SDF-1α stimulation, DGKα is activated and localized at cell protrusion, thus promoting their elongation and mediating SDF-1α induced MMP-9 metalloproteinase secretion and matrix invasion. Phosphatidic acid generated by DGKα promotes localization at cell protrusions of atypical PKCs which play an essential role downstream of DGKα by promoting Rac-mediated protrusion elongation and localized recruitment of β1 integrin and MMP-9. We finally demonstrate that activation of DGKα, atypical PKCs signaling and β1 integrin are all essential for MDA-MB-231 invasiveness. These data indicates the existence of a SDF-1α induced DGKα - atypical PKC - β1 integrin signaling pathway, which is essential for matrix invasion of carcinoma cells

Use of 16S ribosomal RNA gene analyses to characterize the bacterial signature associated with poor oral health in West Virginia

<p>Abstract</p> <p>Background</p> <p>West Virginia has the worst oral health in the United States, but the reasons for this are unclear. This pilot study explored the etiology of this disparity using culture-independent analyses to identify bacterial species associated with oral disease.</p> <p>Methods</p> <p>Bacteria in subgingival plaque samples from twelve participants in two independent West Virginia dental-related studies were characterized using 16S rRNA gene sequencing and Human Oral Microbe Identification Microarray (HOMIM) analysis. Unifrac analysis was used to characterize phylogenetic differences between bacterial communities obtained from plaque of participants with low or high oral disease, which was further evaluated using clustering and Principal Coordinate Analysis.</p> <p>Results</p> <p>Statistically different bacterial signatures (<it>P </it>< 0.001) were identified in subgingival plaque of individuals with low or high oral disease in West Virginia based on 16S rRNA gene sequencing. Low disease contained a high frequency of <it>Veillonella </it>and <it>Streptococcus</it>, with a moderate number of <it>Capnocytophaga</it>. High disease exhibited substantially increased bacterial diversity and included a large proportion of Clostridiales cluster bacteria (<it>Selenomonas</it>, <it>Eubacterium, Dialister</it>). Phylogenetic trees constructed using 16S rRNA gene sequencing revealed that Clostridiales were repeated colonizers in plaque associated with high oral disease, providing evidence that the oral environment is somehow influencing the bacterial signature linked to disease.</p> <p>Conclusions</p> <p>Culture-independent analyses identified an atypical bacterial signature associated with high oral disease in West Virginians and provided evidence that the oral environment influenced this signature. Both findings provide insight into the etiology of the oral disparity in West Virginia.</p

Microbial community succession on developing lesions on human enamel

Dental caries is one of the most common diseases in the world. However, our understanding of how the microbial community composition changes in vivo as caries develops is lacking.An in vivo model was used in a longitudinal cohort study to investigate shifts in the microbial community composition associated with the development of enamel caries.White spot lesions were generated in vivo on human teeth predetermined to be extracted for orthodontic reasons. The bacterial microbiota on sound enamel and on developing carious lesions were identified using the Human Oral Microbe Identification Microarray (HOMIM), which permits the detection of about 300 of the approximate 600 predominant bacterial species in the oral cavity.After only seven weeks, 75% of targeted teeth developed white spot lesions (8 individuals, 16 teeth). The microbial community composition of the plaque over white spot lesions differed significantly as compared to sound enamel. Twenty-five bacterial taxa, including Streptococcus mutans, Atopobium parvulum, Dialister invisus, and species of Prevotella and Scardovia, were significantly associated with initial enamel lesions. In contrast, 14 bacterial taxa, including species of Fusobacterium, Campylobacter, Kingella, and Capnocytophaga, were significantly associated with sound enamel.The bacterial community composition associated with the progression of enamel lesions is specific and much more complex than previously believed. This investigation represents one of the first longitudinally-derived studies for caries progression and supports microbial data from previous cross-sectional studies on the development of the disease. Thus, the in vivo experiments of generating lesions on teeth destined for extraction in conjunction with HOMIM analyses represent a valid model to study succession of supragingival microbial communities associated with caries development and to study efficacy of prophylactic and restorative treatments

The play is a prison : the discourse of Prison Shakespeare.

The relationship between Shakespeare and prison was brought into sharp focus during Shakespeare’s recent quad-centenary with a succession of works exploring Shakespeare’s value for the prison population. In this paper, we take this spike in activity as a point of departure for examining the discourse of Prison Shakespeare. This discourse, we argue, is underpinned by several intertwining and sometimes paradoxical accounts of social being: (i) psychoanalytic accounts; (ii) postmodern accounts; (iii) humanist accounts bound up with the idea of cultural unfolding; (iv) neoliberal accounts that champion heroic individualism. In our analysis, we respond to Pensalfini’s call for critical debate over the assumption that Shakespeare's plays have the power to both teach and liberate prisoners. We note how Prison Shakespeare is always in a struggle to escape the institutional power of both Shakespearean drama and the prison context itself, and the tendency of this work to provide a model of socialization into, rather than resistance against, what Bristol describes as the mode of subjectivity of the bourgeois political economy

Bacterial Diversity in Oral Samples of Children in Niger with Acute Noma, Acute Necrotizing Gingivitis, and Healthy Controls

Noma is a devastating gangrenous disease that leads to severe facial disfigurement, but its cause remains unknown. It is associated with high morbidity and mortality and affects almost exclusively young children living in remote areas of developing countries, particularly in Africa. Several factors have been linked to the disease, including malnutrition, immune dysfunction, lack of oral hygiene, and lesions of the mucosal gingival barrier, particularly the presence of acute necrotizing gingivitis, and a potentially non-identified bacterial factor acting as a trigger for the disease. This study assessed the total bacterial diversity present in 69 oral samples of 55 children in Niger with or without acute noma or acute necrotizing gingivitis using culture-independent molecular methods. Analysis of bacterial composition and frequency showed that diseased and healthy site bacterial communities are composed of similar bacteria, but differ in the prevalence of a limited group of phylotypes. We failed to identify a causative infectious agent for noma or acute necrotizing gingivitis as the most plausible pathogens for both conditions were present also in sizeable numbers in healthy subjects. Most likely, the disease is initiated by a synergistic combination of several bacterial species, and not a single agent

Toksični učinci patulina na timus mužjaka štakora u razvoju

Patulin is a mycotoxin produced by several Penicillium, Aspergillus, and Byssachlamys species growing on food products. In this study, we investigated the effects of patulin on the thymus of growing male rats aged fi ve to six weeks. The rats were receiving it orally at a dose of 0.1 mg kg-1 bw a day for either 60 or 90 days. At the end of the experiment, the thymus was examined for histopathology by light microscopy and for epidermal growth factor (EGF) and its receptor (EGFR) by immunolocalisation. For morphometry we used the Bs200prop program to analyse images obtained with the Olympus BX51 light microscope. Cell ultrastructure was studied by electron microscopy. In rats treated with patulin, the thymus showed haemorrhage, plasma cell hyperplasia, a dilation and fi brosis in the cortex, enlarged interstitial tissue between the thymic lobules, enlarged fat tissue, thinning of the cortex, and blurring of the cortico-medullary demarcation. Electron microscopy showed signs of cell destruction, abnormalities of the nucleus and organelles, and loss of mitochondrial cristae. However, no differences were observed in thymus EGF and EGFR immunoreactivity between treated and control rats.Patulin je mikotoksin koji proizvode plijesni sojeva Penicillium, Aspergillus i Byssachlamys na različitim prehrambenim proizvodima kao podlozi. Učinke patulina istražili smo na timusu mužjaka štakora u razvoju (dobi 5 do 6 tjedana). Mikotoksin je životinjama davan per os u dnevnoj dozi 0,1 mg kg-1 tj. t. 60 odnosno 90 dana. Na kraju pokusa štakori su žrtvovani, timus je podvrgnut histološkim analizama s pomoću svjetlosne mikroskopije, a imunocitokemijskim je metodama istražena stanična lokalizacija epidermalnog faktora rasta (EGF) i njegova receptora (EGFR). Morfometrijska analiza provedena je s pomoću računalnog programa Bs200prop povezanog u sustav sa svjetlosnim mikroskopom Olympus BX51. Elektronskomikroskopski je istražena ultrastruktura stanica timusa. Utvrđeno je da patulin izaziva krvaranja u timusu, hiperplaziju plazma-stanica, dilataciju i fi brozu u kortikalnoj regiji timusa, širenje intersticijskog tkiva između režnjeva timusa, povećanje masnih stanica, smanjenje debljine kore timusa te nestanak kortiko-medularne demarkacije. Elektronskomikroskopski u tkivu timusa štakora tretiranih patulinom uočeni su znakovi raspadanja stanica, abnormalnosti jezgre i organela te gubitak mitohondrijskih krista. Unatoč navedenomu, na presjecima tkiva kontrolnih štakora i štakora tretiranih patulinom nismo utvrdili razlike u imunoreaktivnosti EGF i EGFR, što bi trebalo dodatno istražiti osjetljivijim molekularnim metodama