Genome-Scale Model Reveals Metabolic Basis of Biomass Partitioning in a Model Diatom

Diatoms are eukaryotic microalgae that contain genes from various sources, including bacteria and the secondary endosymbiotic host. Due to this unique combination of genes, diatoms are taxonomically and functionally distinct from other algae and vascular plants and confer novel metabolic capabilities. Based on the genome annotation, we performed a genome-scale metabolic network reconstruction for the marine diatom Phaeodactylum tricornutum. Due to their endosymbiotic origin, diatoms possess a complex chloroplast structure which complicates the prediction of subcellular protein localization. Based on previous work we implemented a pipeline that exploits a series of bioinformatics tools to predict protein localization. The manually curated reconstructed metabolic network iLB1027_lipid accounts for 1,027 genes associated with 4,456 reactions and 2,172 metabolites distributed across six compartments. To constrain the genome-scale model, we determined the organism specific biomass composition in terms of lipids, carbohydrates, and proteins using Fourier transform infrared spectrometry. Our simulations indicate the presence of a yet unknown glutamine-ornithine shunt that could be used to transfer reducing equivalents generated by photosynthesis to the mitochondria. The model reflects the known biochemical composition of P. tricornutum in defined culture conditions and enables metabolic engineering strategies to improve the use of P. tricornutum for biotechnological applications

Effect of sunlight on prokaryotic organic carbon uptake and dynamics of pigments relevant to photoheterotrophy in the Adriatic Sea

Marine photoheterotrophic microorganisms are capable of using light to meet their energy requirements and organic compounds as both carbon and energy sources. We still have little knowledge of the extent to which stimulation of these microorganisms by light could affect the estimates of organic carbon uptake. We evaluated the light and dark prokaryotic organic carbon uptake (H-3-leucine) rates in a grid of stations covering the whole Adriatic Sea during winter and late summer. Light-exposed (photosynthetically active radiation and ultraviolet radiation [UVR]) surface samples were either unaffected, photostimulated or photoinhibited without any clear geographical or seasonal pattern. Light-enhanced leucine uptake occurred only in 23% of assays, suggesting that photoheterotrophy is not a major metabolic strategy and/or it is often counterbalanced by negative effects caused by UVR. Concentrations of bacteriochlorophyll a, zeaxanthin and divinyl chlorophyll a were measured in order to relate 3H-leucine uptake to the distribution of aerobic anoxygenic photo trophs (AAPs), total Cyanobacteria and Prochlorococcus populations, respectively, together with direct estimates of total prokaryotes and Synechococcus abundance. No relationship between light-enhanced leucine uptake and presence of picocyanobacteria or AAPs was evident. Divinyl chlorophyll a concentration was below the limit of detection in February, whereas in late summer the highest values were found around 50 m depth in the central and southern basins. In contrast, bacteriochlorophyll a concentration was correlated to total prokaryote abundance and dissolved organic carbon. Since locally leucine uptake in the light was markedly different from dark controls, in situ light incubations should be more appropriate than dark incubations when carbon budget calculations are intended

Ovine skin organotypic cultures applied to the ex vivo study of orf virus infection

The orf virus is the causal agent of contagious ecthyma; a pustular dermatitis of sheep, goats and humans. The orf is an epitheliotropic virus causing lesions, localized in skin and mucosae, that typically progress through the stages of erythema, papule, pustule and scab. Organotypic human skin cultures (rafts) have already been successfully been used in several research applications (Snoeck et al., 2002) demostrating that they can reproduce the morphology of human skin in vivo. In veterinary medicine, the organotypic skin equivalent could represent an alternative to animal models in the study of the pathogenesis of epitheliotropic viruses. The aim of this study was to develop ovine skin equivalents from differentiated cultures of lamb keratinocytes for the ex vivo study of orf virus infection

Qualit\ue0 dell\u2019acqua in allevamenti di tacchini in Veneto: confronto chimico-fisico e microbiologico tra approvvigionamento con pozzo e con acquedotto

Limited data are available regarding the chemical-physical and microbiological quality of drinking water for turkeys poults in North-eastern Italy. Groundwater is frequently used as a source of supply and may be either unsuitable for drug dissolution and stability or be subjected to contaminant infiltration. Therefore, this study aimed at describing water quality in 14 turkey farms supplied with well water and 14 farms with aqueduct water. Salinity, hardness, pH, ammonia, sulfate, phosphate, nitrate, chromium, copper and iron were quantified in each sample. Total bacterial count at 22 \ub0C and 37 \ub0C, presence and enumeration of Enterococcus spp. and E. coli, and presence of Campylobacter spp. were evaluated. Water samples were collected twice per year (in winter and in summer) at 3 sampling sites: at the water source (A), in the tank where drugs are mixed for medicated water preparation (B) and at the nipple line (C). Results of chemical-physical analyses showed that the quality profile of both sources is frequently within the limit of tap water for human use. However, hardness ranged between 80-500 mg/L and in 70% of farms exceeded 200 mg/L. At site A no farms exceeded 1 mg/L of iron; however, at B-C sites one farm supplied with well water exceeded 1.3 mg/L in both seasons. At site A, microbiological quality of well and aqueduct water was mostly within the limit of tap water for human use. However, both sources had a poor microbiological quality at B and C sites (e.g. up to 4,400 CFU/100 mL of E. coli in well water and 1,300 CFU/100 mL in aqueduct water). Campylobacter spp. wereas rarely isolated; however, the prevalence of positivity by real time PCR was up to 79% in during winter in farms supplied with aqueduct water. These preliminary findings indicate some criticisms in hardness and cleaning/disinfection procedures of pipeline, particularly in farms supplied with well water

Malperfusion Remains the Major Cause of Mortality in Proximal Aortic Operations

WOS: 000293244200014PubMed ID: 21507058Background: This study was undertaken to identify the incremental risk factors for early mortality in operations for proximal aortic pathologies. Methods: Between September 2000 and May 2010, 240 consecutive patients underwent replacement of various portions of the proximal aorta. Mean age was 56 +/- 13 years (range 18 to 84) and female/male ratio was 3/7. Operations were performed emergently in 97, urgently in 21, and electively in 122 patients. Thirty-four patients had previous cardiac or aortic operations. Etiology was acute dissection in 102, chronic dissection in 41, degenerative aneurysm in 61, and other factors (endocarditis, pseudoaneurysm, aortitis, etc.) in 36 patients. The ascending aorta was replaced in all patients. In addition, the aortic arch was replaced in 20 and the root was replaced in 106 patients. Results: The in-hospital mortality rate was 10.4% in the overall group (25/240), 21.6% in emergent cases (21/97), 9.5% in urgent cases (2/21), and 1.6% in elective cases (2/122). Morbidity rates were as follows: stroke 2.7%, temporary neurological dysfunction 13.3%, nonoliguric renal failure 3%, dialysis 5.4%, tracheostomy 3.3%, bleeding requiring revision 3.3%. In multivariate analysis, the presence of malperfusion in patients with acute aortic dissection emerged as the incremental risk factor for mortality (p < 0.0001, odds ratio = 10.37). There was no variable associated with stroke. Emergency/urgency of operation did not emerge as incremental risk factors for mortality. Conclusion: Immediate outcomes of elective aortic operations for proximal aortic pathologies are excellent. Complicated acute dissections with malperfusion remain the major cause of early mortality. doi: 10.1111/j.1540-8191.2011.01250.x (J Card Surg 2011; 26: 393-396

Therapeutic Paint of Cidofovir/Sucralfate Gel Combination Topically Administered by Spraying for Treatment of orf virus Infections

The aim of the research was to study a new cidofovir/sucralfate drug product to be used as a spray for treating the mucosal and/or skin lesions. The product, i.e., a water suspension of sucralfate (15% w/w) and cidofovir (1% w/w), combines the potent antiviral activity of the acyclic nucleoside phosphonate cidofovir ((S)-1-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine) and the wound healing properties of sucralfate gel (sucrose octasulphate basic aluminum salt). The product was characterized in vitro with respect to compatibility between drug and carrier, spray particle size, spray deposition, drying kinetics, and drug content and release. An interaction between the two active substances was found. The interaction between sucralfate and cidofovir was counteracted by introducing sodium dihydrogen phosphate (16% w/w) in the preparation. The spray formulation containing cidofovir/sucralfate gel painted the skin and dried quickly to a scab, remaining firmly adhered to the lesions. The therapeutic paint was tested in vivo on lambs infected with orf virus by treating the animals with different cidofovir/sucralfate formulations (0.5% or 1% cidofovir + sucralfate 15% + NaH2PO4 16% w/w) and with sucralfate gel suspension alone as control. The treatment with formulations containing cidofovir and phosphate salt for four consecutive days resulted in a rapid resolution of the lesions, with scabs containing significantly lower amounts of viable virus when compared with untreated lesions and lesions treated with sucralfate suspension alone

Characteristics of available models for <i>Phaeodactylum tricornutum</i>.

<p>Characteristics of available models for <i>Phaeodactylum tricornutum</i>.</p

Photosynthetic electron flow constraints as determined by Bailleul <i>et al</i>. [83].

<p>Photosynthetic electron flow constraints as determined by Bailleul <i>et al</i>. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155038#pone.0155038.ref083" target="_blank">83</a>].</p

Light-dependent carbon partitioning.

<p>(A) Simulations indicated as photon uptake exceeds carbon uptake, excess redox potential is stored in triacylglycerol. The saturation of carbon uptake is shown in black. (B) Percent of carbon fixed in TAG against percent of metabolite flow through NADHOR (vNADHOR; EC 1.6.5.3,1.6.99.3) over metabolite flow through PSI (vPSI; EC 1.97.1.2) at a super-saturating photon uptake of 22 mM. According to our simulations TAG accumulation is inversely proportional to energetic coupling. TAG accumulation is prohibited when at least 35% of photosynthetically fixed electrons are redirected to the mitochondria.</p

Metabolic network reconstruction workflow.

<p>In step one we obtained a draft reconstruction based on <i>P</i>. <i>tricornutum</i>’s genome annotation and reference reconstructions. This draft reconstruction was manually curated using several resources such as an improved genome annotation, subcellular localization predictions and external databases. All reactions were elementally and charge balanced, QC/QA was performed and a biomass objective function was defined before transforming the reconstruction into a computational model. In an iterative process, the <i>in silico</i> predictions are compared with experimental observations to validate and improve the metabolic model.</p