Structural Design, Development and Testing of a Small Experimental Satellite: SATEX-1

A 50 kg. satellite is being developed at the University of Mexico as an engineering test bed. SATEX-1 is programmed to be launched to polar orbit early in 1995 by Ariane. The satellite structure comprises aluminum sandwich panels and composites in the form of a cube made with two matting U-shaped parts. This solution was selected for simplicity during assembly and testing. The s/c body is further stiffened by an internal panel which supports a pressurized gas tank and other hardware. All panels are joined by standard corner and edge close-outs and splices. At present, a finite element model for the validation of the design, regarding static and dynamic behavior is being conducted. The paper presents numerical results for quasi static and dynamic analysis, such as eigen-values, free vibration and sinusoidal vibrations. The testing program follows closely launcher agency requirements and is supported by previous similar experiences in our laboratory. Also, a general description of the project is included

Data Mining Strategy to Prevent Adverse Drug Events: The Cases of Rosiglitazone and COVID-19 Vaccines

This chapter analyzes how a simple strategy of early detection of safety signals using data mining can prevent the potential risk of adverse events with new or former drugs. We first present the case of an active antidiabetic ingredient, rosiglitazone. The capability of the strategy to detect the risk of heart failure among the data reported during the first 8 years of commercialization was demonstrated 2 years before rosiglitazone was withdrawn from the market in 2020 due to that risk. Ten years later, agility in obtaining safety signals after marketing a drug was put to the test with COVID-19 vaccines. Among adverse events notified during only 2 months of follow-up, we early detected thrombosis following COVID-19 vaccines. Several weeks after, these events were in the spotlight of the vaccination campaign and defined changes in the type of vaccine administered according to susceptible age groups. This early analysis strategy of suspected adverse drug reactions reported can provide useful information in making decisions in a faster way than the standard data mining methodology

Specificity traits consistent with legume-rhizobia coevolution displayed by Ensifer meliloti rhizosphere colonization

Rhizobia are α‐ and ß‐proteobacteria that associate with legumes in symbiosis to fix atmospheric nitrogen. The chemical communication between roots and rhizobia begins in the rhizosphere. Using signature‐tagged‐Tn5 mutagenesis (STM) we performed a genome‐wide screening for Ensifer meliloti genes that participate in colonizing the rhizospheres of alfalfa and other legumes. The analysis of ca. 6,000 mutants indicated that genes relevant for rhizosphere colonization account for nearly 2% of the rhizobial genome and that most (ca. 80%) are chromosomally located, pointing to the relevance and ancestral origin of the bacterial ability to colonize plant roots. The identified genes were related to metabolic functions, transcription, signal transduction, and motility/chemotaxis among other categories; with several ORFs of yet‐unknown function. Most remarkably, we identified a subset of genes that impacted more severely the colonization of the roots of alfalfa than of pea. Further analyses using other plant species revealed that such early differential phenotype could be extended to other members of the Trifoliae tribe (Trigonella, Trifolium), but not the Fabeae and Phaseoleae tribes. The results suggest that consolidation of E. meliloti into its current symbiotic state should have occurred in a rhizobacterium that had already been adapted to rhizospheres of the Trifoliae tribe.Instituto de Biotecnologia y Biologia Molecula

Transkriptomische Analysen zur Xanthanproduktion in Xanthomonas campestris pv. campestris

Serrania Vallejo J. Transkriptomische Analysen zur Xanthanproduktion in Xanthomonas campestris pv. campestris. Bielefeld (Germany): Bielefeld University; 2008.Xanthomonas campestris pv. campestris (Xcc) wird industriell zur Produktion des Exopolysaccharids Xanthan verwendet, das z.B. in der Lebensmittelindustrie als Verdickungsmittel eingesetzt wird. Xcc ist ebenfalls der Erreger der Aderschwärze bei der Pflanzenfamilie der Kreuzblütengewächse. In dieser Arbeit wurde ein genomweites transkriptomisches Profil einer Kultivierung in einem 10 L Bioreaktor erstellt. Zur Transkriptionsanalyse wurde der kürzlich entwickelte Microarray Xcc5kOLI verwendet. Es konnten zwei Genregionen identifiziert werden, die ein wachstumsphasenspezifisches Transkriptionsprofil aufwiesen. Eine der zwei Genregionen beinhaltet hauptsächlich Gene ribosomaler Proteine und zeigte eine Induktion in der exponentiellen und eine Repression in der stationären Wachstumsphase. Dieses Profil spiegelt wahrscheinlich die allgemeine metabolische Aktivität der Bakterienkultur wieder. Die zweite Genregion beinhaltet hauptsächlich Gene, die in die Flagellar-Biosynthese involviert sind. Diese Gene zeichnen sich durch eine Induktion in der exponentiellen und eine kurze erneute Induktion zu Beginn der stationären Phase aus. Zu Zwecken der Stammoptimierung des Produktionsstammes Xcc LMG 8031* wurde untersucht, ob die Inaktivierung der Motilität zu einer Erhöhung der Biomasse- oder Xanthanproduktion führt. Hierfür wurden Stämme produziert, die Deletionen in den Genen fleQ und flgE tragen. Das Gen fleQ kodiert für einen Regulator der Flagellar-Biosynthese und flgE für das Strukturprotein des Flagellar-Ankers. Beide Deletionen führten zu einem nicht motilen Phänotyp. Das transkriptomische Profil des Gens galU wies eine Reduktion der Genexpression im Übergang zur stationären Phase auf. GalU katalysiert die Umwandlung von Glucose-1-Phosphat zu UDP-Glucose, welches für die Xanthanproduktion benötigt wird. Durch Klonierung eines konstitutiv hoch exprimierten Promotors vor das galU-Gen wurde der Einfluss einer Überexpression auf die Xanthanproduktion untersucht. Weder die Verwendung der nicht motilen Stämme, mit den Deletionen in den Genen fleQ bzw. flgE, noch die Überexpression des galU-Gens führten zu einer erhöhten Biomasse- oder Xanthanproduktion. Ein weiterer Schwerpunkt dieser Arbeit war die Analyse der Kohlenstoffverwertung in Xcc. Hierfür wurden transkriptomische Analysen zur Kurzzeit- und Langzeitantwort des Stammes Xcc B100 auf die Anwesenheit von Galactose durchgeführt. Es konnten in dieser Arbeit drei Genregionen identifiziert werden, die sowohl im Kurzzeit- als auch Langzeitwachstum in Galactose eine Induktion der Gene im Vergleich zum Wachstum in Glucose aufweisen. Diese Genregionen beinhalteten unter anderem Gene für Glycosidasen, die in das Periplasma oder ins Medium exportiert werden. Ebenfalls sind die Gene zweier TonB-abhängiger Rezeptoren in den Genregionen lokalisiert, die für den Transport von Galactose durch die äußere Membran zuständig sein können. Das Genprodukt des Gens sglT konnte als möglicher Galactosetransporter durch die innere Membran identifiziert werden. Auch liegen Gene für Enzyme des Galactoseabbaus im Cytoplasma in den Galactose-Verwertungsregionen. Somit war es möglich, mit den Genen der drei identifizierten Galactose-Verwertungsregionen ein Modell der Galactoseverwertung in Xcc zu entwickeln

Early Signal Detection: Data Mining of Mental Disorders with Statins

Statins are widely prescribed to treat dyslipidemias. It is well-known adverse reaction of these active ingredients related to rhabdomyolysis and myalgia, but there are other signals to be aware of, such as mental disorders. Pharmacovigilance tools help to trace known risks and detect early other unknown effects that appear over time. Data of all the reported suspected adverse drug reactions for statins from the international World Health Organization (WHO) repository Vigibase were analyzed with an adaptation of data mining Bayesian methodology to search for positive signals, threshold of false discovery rate (FDR) < 0.05, and listed candidates for priority clinical investigation. Among positive mental signals observed, some were currently stated as adverse reactions in technical factsheets as insomnia, depression, dementia, and nightmares, but others have not reached this condition as bipolar, psychotic, and emotional disorders or symptoms and suicide. Other diverse central positive signals that can be confounded with mental conditions obtained and not stated were senses impairment, such as blindness, deafness, balance disorder, and events related to suicide. Worrying positive signals proposed as candidates to further investigation are insomnia for pitavastatin, pravastatin, and simvastatin; dementia for atorvastatin and rosuvastatin; and suicide and psychotic disorders for atorvastatin, lovastatin, pravastatin, rosuvastatin, and simvastatin

Fine-tuning of galactoglucan biosynthesis in Sinorhizobium meliloti by differential wggR (expG)-, PhoB-, and mucR-dependent regulation of two promoters

Bahlawane C, Baumgarth B, Serrania J, Rueberg S, Becker A. Fine-tuning of galactoglucan biosynthesis in Sinorhizobium meliloti by differential wggR (expG)-, PhoB-, and mucR-dependent regulation of two promoters. JOURNAL OF BACTERIOLOGY. 2008;190(10):3456-3466

Identification of Xanthomonas campestris pv. campestris galactose utilization genes from transcriptome data

Serrania J, Vorhölter F-J, Niehaus K, Pühler A, Becker A. Identification of Xanthomonas campestris pv. campestris galactose utilization genes from transcriptome data. Journal of Biotechnology. 2008;135(3):309-317.A 70 met oligonucleotide microarray was constructed to analyze genome-wide expression profiles of Xanthomonas campestris pv. campestris B100, a plant-pathogenic bacterium that is industrially employed to produce the exopolysaccharide xanthan gum which has many applications as a stabilizing, thickening, gelling, and emulsifying agent in food, pharmaceutical, and cosmetic industries. As an application example, global changes of gene expression were monitored during growth of X. campestris pv. campestris B100 on two different carbon sources. Exponential growing bacterial cultures were incubated either for 1 h or permanently in minimal medium supplemented with 1% galactose in comparison to growth in minimal medium supplemented with 1% glucose. Six genes were identified that were significantly increased in gene expression under both growth conditions. These genes were located in three distinguished chromosomal regions in operon-like gene clusters. Genes from these clusters encode secreted glycosidases, which were predicted to be specific for galactose-containing carbohydrates, as well as transport proteins probably located in the outer and inner cell membrane. Finally genes from one cluster code for cytoplasmic enzymes of a metabolic pathway specific for the breakdown of galactose to intermediates of glycolysis. (C) 2008 Elsevier B.V. All rights reserved

<i>sX13</i> contributes to bacterial growth in culture and virulence.

<p>Growth of <i>Xcv</i> wild type 85-10 (wt), the <i>sX13</i> deletion mutant (Δ<i>sX13</i>) and Δ<i>sX13</i> containing chromosomally re-integrated <i>sX13</i> (Δ<i>sX13</i>+<i>sX13</i>_ch) in (A) complex medium NYG and (B) minimal medium MMA, respectively. Error bars represent standard deviations. Asterisks indicate statistically significant differences compared to wt (<i>t</i>-test; <i>P</i><0.05). (C) Growth of <i>Xcv</i> 85-10 (wt) and Δ<i>sX13</i> in leaves of susceptible ECW pepper plants. Data points represent the mean of three different samples from three different plants of one experiment. Standard deviations are indicated by error bars. (D) Plant infection assay. <i>Xcv</i> strains 85-10 (wt) and Δ<i>sX13</i> carrying the empty vector (pB) or the sX13 expression construct (p<i>sX13</i>) and strains additionally expressing HrpG* (p<i>hrpG*</i>) were inoculated at a density of 4×10⁸ (left panel) and 10⁸ cfu/ml (right panel), respectively, into leaves of susceptible ECW and resistant ECW-10R pepper plants. Disease symptoms in ECW were photographed 9 days post inoculation (dpi). The HR was visualized by ethanol bleaching of the leaves 3 dpi (left panel) and 18 hours post inoculation (right panel), respectively. Dashed lines indicate the inoculated areas. All experiments were performed at least three times with similar results.</p