463 research outputs found
A re-evaluation of M. prototuberculosis
It has been suggested that a group of smooth tubercle bacilli, isolated from patients with tuberculosis and associated with Djibouti, East Africa, along with the seven species and subspecies that are traditional members of the Mycobacterium tuberculosis complex, should be considered a single species. This suggestion is based on the sequence similarity of the16S rRNA and segments of six housekeeping genes. The very concept of bacterial species is now subject to debate, and I follow the lead of Maynard Smith, who, in a review of the bacterial species concept, suggested that using genetic distance to define bacterial species was âarbitrary and of little meritâ. If defining a species by sequence diversity alone is controversial, then it is important to carefully examine the recent claim that strains of M. tuberculosis are descendants and members of a much more ancient and large bacterial species called Mycobacterium prototuberculosis. Furthermore, given the importance of M. tuberculosis as a human pathogen and the implications for research, it is important to verify the claim that our remote hominid ancestors may have suffered from tuberculosis and that the tubercle bacilli originated in Africa
Emergence d'une science des systÚmes supramoléculaires à l'Université de Strasbourg (1961-2011) - Du paradigme de la chimie supramoléculaire à un héritage organisationnel ?
112 page
MATHEMATICS ANXIETY AND THE ACADEMIC PERFORMANCE OF THE FRESHMEN COLLEGE STUDENTS OF THE NAVAL STATE UNIVERSITY
The main objective of this study was to determine the relationship between the level of Mathematics anxiety and the academic performance of the students at the Naval State University. The data were gathered through the questionnaire from the 200 student-respondents. More than three-fourths or 82.5 percent of the studentsâ involved in the study aged between 16 and 18 years old. Almost one-half or 48.5 percent of the students was rated âGoodâ as school grades in Mathematics; 86 percent had favorable attitude towards Mathematics; 44 percent from the total number of students were from the College of Engineering (COE) and College of Arts and Sciences (CAS). The remaining 42 percent were from the College of Industrial Information and Communication Technology (CIICT) and College of Maritime Education (COME). More than one-half or 64.5 percent of the students have Average Anxiety. Highest Percentage of 18.5 percent from COE,17.5 percent from COME, 16 percent from CAS, and 12.5 percent from CIICT. Topping among the other Colleges was the College of Engineering (COE) when it comes to mathematics performance, 17 % of them were rated as â Satisfactoryâ. Majority of the teachers ( 79.5 % ) were democratic in their approach in teaching Mathematics. None of the teachers from the CIICT department used autocratic approach. Other teachers from other Colleges used Democratic, sometimes autocratic or a combination of both
Evolution of the Chalcone Isomerase Fold from Fatty Acid-Binding to Stereospecific Enzyme
Specialized metabolic enzymes biosynthesize chemicals of ecological importance, often sharing a pedigree with primary metabolic enzymes1. However, the lineage of the enzyme chalcone isomerase (CHI) remained a quandary. In vascular plants, CHI-catalyzed conversion of chalcones to chiral (S)-flavanones is a committed step in the production of plant flavonoids, compounds that contribute to attraction, defense2, and development3. CHI operates near the diffusion limit with stereospecific control4,5. While associated primarily with plants, the CHI-fold occurs in several other eukaryotic lineages and in some bacteria. Here we report crystal structures, ligand-binding properties, and in vivo functional characterization of a non-catalytic CHI-fold family from plants. A. thaliana contains five actively transcribed CHI-fold genes, three of which additionally encode amino-terminal chloroplast-transit sequences (cTP). These three CHI-fold proteins localize to plastids, the site of de novo fatty acid (FA) biosynthesis in plant cells. Furthermore, their expression profiles correlate with those of core FA biosynthetic enzymes, with maximal expression occurring in seeds and coinciding with increased FA storage in the developing embryo. In vitro, these proteins are Fatty Acid-binding Proteins (FAP). FAP knockout A. thaliana plants exhibit elevated alpha-linolenic acid levels and marked reproductive defects, including aberrant seed formation. Notably, the FAP discovery defines the adaptive evolution of a stereospecific and catalytically âperfectedâ enzyme6 from a non-enzymatic ancestor over a defined period of plant evolution
Evaluation De Lâeffet De Lâextrait Aqueux Des Feuilles De Abrus Precatorius (Fabaceae) Sur Le Poids Et La Prise Alimentaire Chez Des Rats
Abrus precatorius est reconnue dans le monde pour ses nombreuses vertus thĂ©rapeutiques en mĂ©dicine traditionnelle. Des Ă©tudes ont montrĂ© que lâextrait aqueux de ses feuilles est non toxique par voie orale chez des rats, ce qui pourrait justifier son innocuitĂ© observĂ©e chez lâhomme en mĂ©dicine traditionnelle. La prĂ©sente Ă©tude a pour objectif de rechercher lâeffet de lâextrait aqueux des feuilles de A. precatorius sur le poids corporel et la prise alimentaire des rats traitĂ©s contre les tĂ©moins traitĂ©s Ă lâeau distillĂ©e. Au cours de cette Ă©tude expĂ©rimentale de 21 jours, les animaux au nombre de 12 ont Ă©tĂ© rĂ©partis dans des cages individuelles puis regroupĂ©s en deux groupes de 6. Ils ont Ă©tĂ© gavĂ©s chaque jour Ă deux doses (2ml/100g) des substances dâessai (matin/soir) pendant 7 jours et observĂ©s pendant 14 jours aprĂšs lâarrĂȘt du gavage. Afin de dĂ©terminer lâinfluence de lâextrait Ă la dose efficace (40 mg/ml) sur la croissance et la prise alimentaire des rats, lâĂ©volution de ces deux paramĂštres a Ă©tĂ© suivie pĂ©riodiquement tout au long de lâexpĂ©rimentation. Les resultats obtenues montrent que lâextrait aqueux des feuilles de A. precatorius Ă la dose efficace (40 mg/ml) ne provoque pas de changement sur le poids et lâalimentation des rats. Tous ces rĂ©sultats viennent justifier les nombreuses utilisations de la plante Abrus precatorius en mĂ©dicine traditionnelle.
Abrus precatorius is recognized worldwide for its many therapeutic virtues in traditional medicine. Studies have shown that the aqueous extract of its leaves is nontoxic orally in rats, which could justify its harmlessness observed in humans in traditional medicine. The purpose of this study is to investigate the effect of aqueous extract of A. precatorius leaves on body weight and feed intake of the treated rats against distilled water controls. During this 21-day experimental study, the 12 animals were distributed in individual cages and then grouped into two groups ofsix. They were force-fed every day with two doses (2ml / 100g) of the test substances. (Morning / evening) for 7 days and observe for 14 days after stopping force-feeding. In order to determine the influence of the extract at the effective dose (40 mg / ml) on the growth and feeding of the rats, the evolution of these two parameters was periodically monitored throughout the experiment. The results obtained show that the aqueous extract of A. precatorius leaves at the effective dose (40 mg / ml) does not cause any change in the weight and diet of the rats. All these results justify the many uses of the plant Abrus precatorius in traditional medicine
Visualizing the Interface of Biotin and Fatty Acid Biosynthesis through SuFEx Probes
Site-specific covalent conjugation offers a powerful tool to identify and understand protein-protein interactions. In this study, we discover that sulfur fluoride exchange (SuFEx) warheads effectively crosslink the Escherichia coli acyl carrier protein (AcpP) with its partner BioF, a key pyridoxal 5âČ-phosphate (PLP)-dependent enzyme in the early steps of biotin biosynthesis by targeting a tyrosine residue proximal to the active site. We identify the site of crosslink by MS/MS analysis of the peptide originating from both partners. We further evaluate the BioF-AcpP interface through protein crystallography and mutational studies. Among the AcpP-interacting BioF surface residues, three critical arginine residues appear to be involved in AcpP recognition so that pimeloyl-AcpP can serve as the acyl donor for PLP-mediated catalysis. These findings validate an evolutionary gain-of-function for BioF, allowing the organism to build biotin directly from fatty acid biosynthesis through surface modifications selective for salt bridge formation with acidic AcpP residues.</p
The chemopreventive polyphenol Curcumin prevents hematogenous breast cancer metastases in immunodeficient mice
Dissemination of metastatic cells probably occurs long before diagnosis of the primary tumor. Metastasis during early phases of carcinogenesis in high risk patients is therefore a potential prevention target. The plant polyphenol Curcumin has been proposed for dietary prevention of cancer. We therefore examined its effects on the human breast cancer cell line MDA-MB-231 in vitro and in a mouse metastasis model. Curcumin strongly induces apoptosis in MDA- MB- 231 cells in correlation with reduced activation of the survival pathway NF kappa B, as a consequence of diminished I kappa B and p65 phosphorylation. Curcumin also reduces the expression of major matrix metalloproteinases (MMPs) due to reduced NF kappa B activity and transcriptional downregulation of AP-1. NF kappa B/p65 silencing is sufficient to downregulate c-jun and MMP expression. Reduced NF kappa B/AP-1 activity and MMP expression lead to diminished invasion through a reconstituted basement membrane and to a significantly lower number of lung metastases in immunodeficient mice after intercardiac injection of 231 cells (p=0.0035). 68% of Curcumin treated but only 17% of untreated animals showed no or very few lung metastases, most likely as a consequence of down-regulation of NF kappa B/AP-1 dependent MMP expression and direct apoptotic effects on circulating tumor cells but not on established metastases. Dietary chemoprevention of metastases appears therefore feasible. Copyright (c) 2007 S. Karger AG, Basel
Global Burden of Cardiovascular Diseases and Risk Factors, 1990-2019: Update From the GBD 2019 Study
Cardiovascular diseases (CVDs), principally ischemic heart disease (IHD) and stroke, are the leading cause of global mortality and a major contributor to disability. This paper reviews the magnitude of total CVD burden, including 13 underlying causes of cardiovascular death and 9 related risk factors, using estimates from the Global Burden of Disease (GBD) Study 2019. GBD, an ongoing multinational collaboration to provide comparable and consistent estimates of population health over time, used all available population-level data sources on incidence, prevalence, case fatality, mortality, and health risks to produce estimates for 204 countries and territories from 1990 to 2019. Prevalent cases of total CVD nearly doubled from 271 million (95% uncertainty interval [UI]: 257 to 285 million) in 1990 to 523 million (95% UI: 497 to 550 million) in 2019, and the number of CVD deaths steadily increased from 12.1 million (95% UI:11.4 to 12.6 million) in 1990, reaching 18.6 million (95% UI: 17.1 to 19.7 million) in 2019. The global trends for disability-adjusted life years (DALYs) and years of life lost also increased significantly, and years lived with disability doubled from 17.7 million (95% UI: 12.9 to 22.5 million) to 34.4 million (95% UI:24.9 to 43.6 million) over that period. The total number of DALYs due to IHD has risen steadily since 1990, reaching 182 million (95% UI: 170 to 194 million) DALYs, 9.14 million (95% UI: 8.40 to 9.74 million) deaths in the year 2019, and 197 million (95% UI: 178 to 220 million) prevalent cases of IHD in 2019. The total number of DALYs due to stroke has risen steadily since 1990, reaching 143 million (95% UI: 133 to 153 million) DALYs, 6.55 million (95% UI: 6.00 to 7.02 million) deaths in the year 2019, and 101 million (95% UI: 93.2 to 111 million) prevalent cases of stroke in 2019. Cardiovascular diseases remain the leading cause of disease burden in the world. CVD burden continues its decades-long rise for almost all countries outside high-income countries, and alarmingly, the age-standardized rate of CVD has begun to rise in some locations where it was previously declining in high-income countries. There is an urgent need to focus on implementing existing cost-effective policies and interventions if the world is to meet the targets for Sustainable Development Goal 3 and achieve a 30% reduction in premature mortality due to noncommunicable diseases
Buffy the vampire slayer: what being Jewish has to do with it
This article examines the whiteness in the television series Buffy the Vampire Slayer. The author argues that the showâs overwhelming whiteness is a product of a generalized white anxiety about the numerical loss of white dominance across the United States and, in particular, in California. The article goes on to think through the role that Jewishness plays in the program, discussing the relationship between the apparently Anglo-American Buffy, played by a Jewish actor, and her sidekick, Willow, who is characterized as Jewish but is played by a non-Jewish actor. The evil master in the first series is given Nazi characteristics and the destruction that he wants to inflict carries connotations of the Holocaust. Structurally, Buffy is produced as the Jew who saves the United States from this demonic destruction. In this traumatic renarrativising, the Holocaust comes to stand for the white-experienced crisis of the loss of white supremacy in the United States. With this reading we can begin to understand the showâs popularity among early adult, predominantly white Americans
The time is now: Achieving FH paediatric screening across Europe â The Prague Declaration
ReviewFamilial Hypercholesterolaemia (FH) is severely under-recognized, under-diagnosed and under-treated in Europe, leading to a significantly higher risk of premature cardiovascular diseases in those affected. FH stands for inherited, very high cholesterol and affects 1:300 individuals regardless of their age, race, sex, and lifestyle, making it the most common inherited metabolic disorder and a non-modifiable cardiovascular disease risk factor in the world..info:eu-repo/semantics/publishedVersio
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