Taxonomy and chemical characterization of new antibiotics produced by Saccharothrix SA198 isolated from a Saharan soil

Actinomycete strain SA198, isolated from a Saharan soil sample of Algeria, exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria, and phytopathogenic and toxinogenic fungi. The morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus Saccharothrix. Analysis of the 16S rRNA gene sequence of strain SA198 showed a similarity level ranging between 97.2 and 98.8% within Saccharothrix species, S. australiensis being the most closely related. Two new active products were isolated by reverse HPLC using a C18 column. The ultraviolet–visible (UV–VIS), infrared (IR), mass, and 1Hand 14C nuclear magnetic resonance (NMR) spectra showed that these products were new bioactive compounds. The minimum inhibitory concentrations of these antibiotics showed a strong activity against fungi and moderate activities against Gram-positive and Gram-negative bacteria

de Haas-van Alphen oscillations in the underdoped cuprate YBa2_2Cu3_3O6.5_{6.5}

The de Haas-van Alphen effect was observed in the underdoped cuprate YBa$_2$Cu$_3$O$_{6.5}$ via a torque technique in pulsed magnetic fields up to 59 T. Above an irreversibility field of $\sim$30 T, the magnetization exhibits clear quantum oscillations with a single frequency of 540 T and a cyclotron mass of 1.76 times the free electron mass, in excellent agreement with previously observed Shubnikov-de Haas oscillations. The oscillations obey the standard Lifshitz-Kosevich formula of Fermi-liquid theory. This thermodynamic observation of quantum oscillations confirms the existence of a well-defined, close and coherent, Fermi surface in the pseudogap phase of cuprates.Comment: published versio

High frequency magnetic oscillations of the organic metal θ\theta-(ET)4_4ZnBr4_4(C6_6H4_4Cl2_2) in pulsed magnetic field of up to 81 T

De Haas-van Alphen oscillations of the organic metal $\theta$-(ET)$_4$ZnBr$_4$(C$_6$H$_4$Cl$_2$) are studied in pulsed magnetic fields up to 81 T. The long decay time of the pulse allows determining reliable field-dependent amplitudes of Fourier components with frequencies up to several kiloteslas. The Fourier spectrum is in agreement with the model of a linear chain of coupled orbits. In this model, all the observed frequencies are linear combinations of the frequency linked to the basic orbit $\alpha$ and to the magnetic-breakdown orbit $\beta$.Comment: 6 pages, 4 figure

Ovulation rate and early embryonic survival rate in female rabbits of a synthetic line and a local Algerian population

[EN] A higher litter size at birth has been reported in female rabbits from a Synthetic line than in those of the Local Algerian population. The aim of this work was to analyse whether this difference in litter size was due to a higher ovulation rate and/or embryonic survival rate in Synthetic line than in Local Algerian population. In total, 24 multiparous female rabbits from Synthetic line and 23 from Local population were used in this experiment. Litter size at birth was recorded up to the first 3 parities. Litter size was 20% higher in Synthetic line than Local population. At their 4th gestation, the females were euthanized at 72 h post coitum. Synthetic line females had 50% more ova and embryos than those of Local population (+4.42 ova and +3.92 embryos, respectively). Synthetic line displayed a lower percentage of normal embryos and a larger number of unfertilized oocytes than Local population (–2.81% and +0.64 oocytes, respectively), but differences were not relevant. Synthetic line showed a lesser embryonic stage of development at 72 h post coitum, showing a higher percentage of early morulae (31.50 vs. 8.50%) and a lower percentage of compact morulae (51.45 vs. 78.65%) than Local population. No relevant difference was found for early embryonic survival rate between Synthetic line and Local population. In conclusion, the difference in litter size was mainly due to a higher ovulation rate in the Synthetic line, allowing more embryos to develop in this line.Belabbas, R.; García, M.; Ainbaziz, H.; Berbar, A.; Zitouni, G.; Lafri, M.; Bouzouan, M.... (2016). Ovulation rate and early embryonic survival rate in female rabbits of a synthetic line and a local Algerian population. World Rabbit Science. 24(4):275-282. doi:10.4995/wrs.2016.5301.SWORD275282244Argente, M. J., Santacreu, M. A., Climent, A., & Blasco, A. (2003). Relationships between uterine and fetal traits in rabbits selected on uterine capacity1. Journal of Animal Science, 81(5), 1265-1273. doi:10.2527/2003.8151265xBelabbas R., AinBaziz H., Ilès I., Zenia S., Boumahdi Z., Boulbina I., Temim S. 2011. Study of prolificacy and its main biological components in rabbits of local Algerian population (Oryctolagus cuniculus). Livest. Res. Rur. Dev., 23: 61.Brun J.M., Baselga M. 2004. Analysis of reproductive performances during the formation of a rabbit synthetic strain. In Proc.: 8th World Rabbit Congress, September 7-10, 2004, Puebla, Mexico, 32-37.Bolet, G., & Theau-Clément, M. (1994). Fertilisation rate and preimplantation embryonic development in two rabbit strains of different fecundity, in purebreeding and crossbreeding. Animal Reproduction Science, 36(1-2), 153-162. doi:10.1016/0378-4320(94)90062-0Buhi, W. C., & Alvarez, I. M. (2003). Identification, characterization and localization of three proteins expressed by the porcine oviduct. Theriogenology, 60(2), 225-238. doi:10.1016/s0093-691x(03)00027-xGacem M., Lebas F. 2000. Rabbit husbandry in Algeria. Technical structure and evaluation of performances. World Rabbit Sci., 8(Suppl. 1): B75-80.Gacem M., Zerrouki N., Lebas F., Bolet G., 2008. Strategy of developing rabbit meat in Algeria: creation and selection of a synthetic strain. In Proc.: 9th World Rabbit Congress, June 10-13, 2008, Verona, Italy, 85-89.Nancarrow C.D., Hill J.L. 1995. Oviduct proteins in fertilization and early embryo development. J. Reprod. Fertil., (Suppl) 49: 3-13.Salvetti P., Guérin P., Theau-Clément M., Hurtaud J., Beckers J.F., Joly T. 2007. Essais d'amélioration de la production d'embryons chez la lapine. In Proc.: 12èmes Journées de la Recherche Cunicole, 27-28 Novembre 2007, Le Mans, France, 41-44.Xie, S., Broermann, D. M., Nephew, K. P., Bishop, M. D., & Pope, W. F. (1990). Relationship between oocyte maturation and fertilization on zygotic diversity in swine. Journal of Animal Science, 68(7), 2027. doi:10.2527/1990.6872027xYoussef Y.K., Iraqi M.M., El-Raffa A.M., Afifi E.A., Khalil M.H., García M.L., Baselga M. 2008. A joint project to synthesize new lines of rabbits in Egypt and Saudi Arabia: emphasis for results and prospects. In Proc.: 9th World Rabbit Congress, June 10-13, 2008, Verona, Italy, 1637-1642

Saccharothrix sp. PAL54, a new chloramphenicol-producing strain isolated from a Saharan soil

An actinomycete strain designated PAL54, producing an antibacterial substance, was isolated from a Saharan soil in Ghardaïa, Algeria. Morphological and chemical studies indicated that this strain belonged to the genus Saccharothrix. Analysis of the 16S rDNA sequence showed a similarity level ranging between 96.9 and 99.2% within Saccharothrix species, with S. longispora DSM 43749T, the most closely related. DNA–DNA hybridization confirmed that strain PAL54 belonged to Saccharothrix longispora. It showed very strong activity against pathogenic Gram-positive and Gram-negative bacteria responsible for nosocomial infections and resistant to multiple antibiotics. Strain PAL54 secreted the antibiotic optimally during mid-stationary and decline phases of growth. One antibacterial compound was isolated from the culture broth and purified by HPLC. The active compound was elucidated by uv-visible and NMR spectroscopy and by mass spectrometry. The results showed that this compound was a D(-)-threo chloramphenicol. This is the first report of chloramphenicol production by a Saccharothrix species

Facteurs associés au mauvais contrôle glycémique chez des diabétiques de type 2 au Nord-Est du Maroc : à propos de 80 cas

Malgré les efforts déployés dans la prise en charge du diabète, une proportion encore élevée de diabétiques connait un mauvais contrôle glycémique qui constitue le facteur le plus déterminant des complications et du décès prématuré liés au diabète 2.L’objectif de ce travail était d’identifier les facteurs de risque potentiels qui seraient associés au mauvais contrôle glycémique chez des diabétiques au niveau de la ville de Nador. A ce propos, une enquête a été entreprise auprès de ces patients en prenant comme indicateur biologique les taux d’hémoglobine glyquée « HbA1c ».Les femmes représentaient 90% des enquêtés et l’âge moyen était de 59,96 ± 2,07 ans. Les niveaux de HbA1c étaient supérieurs à 9% pour près de 54%. La population en question se caractérise par un bas niveau d’instruction (90%), un statut socioéconomique fragile, des taux inquiétants de surpoids (47%) et d’obésité (44%) et par des comportements hygiéno-diététiques insatisfaisants.Agir sur les déterminants socioéconomiques et réformer la prise en charge des diabétiques amélioreraient leur état de santé et limiteraient la survenue précoce des complications liées à cette maladie. 

Climatic zone and soil properties determine the biodiversity of the soil bacterial communities associated to native plants from desert areas of north-central algeria

Algeria is the largest country in Africa characterized by semi-arid and arid sites, located in the North, and hypersaline zones in the center and South of the country. Several autochthonous plants are well known as medicinal plants, having in common tolerance to aridity, drought and salinity. In their natural environment, they live with a great amount of microbial species that altogether are indicated as plant microbiota, while the plants are now viewed as a \u201cholobiont\u201d. In this work, the microbiota of the soil associated to the roots of fourteen economically relevant autochthonous plants from Algeria have been characterized by an innovative metagenomic approach with a dual purpose: (i) to deepen the knowledge of the arid and semi-arid environment and (ii) to characterize the composition of bacterial communities associated with indigenous plants with a strong economic/commercial interest, in order to make possible the improvement of their cultivation. The results presented in this work highlighted specific signatures which are mainly determined by climatic zone and soil properties more than by the plant species

Actinopolyspora algeriensis sp. nov., a novel halophilic actinomycete isolated from a Saharan soil

A halophilic actinomycete strain designated H19T, was isolated from a Saharan soil in the Bamendil region (Ouargla province, South Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the strain were consistent with those of members of the genus Actinopolyspora, and 16S rRNA gene sequence analysis confirmed that strain H19T was a novel species of the genus Actinopolyspora. DNA–DNA hybridization value between strain H19T and the nearest Actinopolyspora species, A. halophila, was clearly below the 70 % threshold. The genotypic and phenotypic data showed that the organism represents a novel species of the genus Actinopolyspora for which the name Actinopolyspora algeriensis sp. nov. is proposed, with the type strain H19T (= DSM 45476T = CCUG 62415T)

Modulation of endogenous antioxidant defense and the progression of kidney disease in multi-heritage groups of patients with type 2 diabetes: PRospective EValuation of Early Nephropathy and its Treatment (PREVENT).

BACKGROUND: Diabetes is the western world's leading cause of end-stage renal disease. Glucose-dependent, oxidative stress is linked to the development of renal inflammation and sclerosis, which, in animal models of diabetes, can be prevented by anti-oxidative treatment. Patients of non-Caucasian heritage have low activity of the selenoprotein, antioxidant enzyme, glutathione peroxidase (GPx) and its co-factor vitamin E, which may be linked to their increased propensity to developing end-stage renal disease. RESEARCH DESIGN AND METHODS: We have designed a double-blind, randomized, placebo controlled study with selenium and/or vitamin E versus placebo as the interventions for patients with type 2 diabetes and chronic kidney disease (CKD) stages 1-3. A 2 × 2 factorial design will allow a balanced representation of the heritage groups exposed to each intervention. The primary biochemical outcome is change in GPx activity, and clinical outcome measure is the actual, rate of-and/or percentage change in estimated glomerular filtration rate (eGFR) from baseline. Analysis will be with a marginal model for longitudinal data using Generalized Estimating Equations corrected for measures of baseline serum antioxidant enzyme activities (GPx, superoxide dismutase and catalase), micronutrient levels (vitamins E and C), measures of inflammation (interleukin 6, c-reactive protein and monocyte chemoattractant protein-1) and markers of oxidative damage (plasma 8-isoprostaglandin F2α and urinary 8-hydroxydeoxyguanosine). EXPECTED RESULTS: The study will assess the relationship between GPx activity, oxidative stress, inflammation and eGFR. It will test the null hypothesis that antioxidant therapy does not influence the activity of GPx or other antioxidant enzymes and/or alter the rate of change in eGFR in these patient groups. CONCLUSIONS: Outcome data on the effect of antioxidants in human diabetic renal disease is limited. Previous post hoc analyses have not shown a beneficial effect of vitamin E on renal function. A recent trial of a pharmaceutical antioxidant agent, improved eGFR, but in patients with advanced diabetes-related chronic kidney disease its use was associated with an increased incidence of cardiovascular events. We will explore whether the nutritional antioxidants, vitamin E and selenium alone, or in combination in patients at high risk of renal disease progression, forestalls a reduction in eGFR. The study will describe whether endogenous antioxidant enzyme defenses can be safely modified by this intervention and how this is associated with changes in markers of oxidative stress. Trial registration ISRCTN 97358113. Registered 21st September 2009

Theory of quantum magneto-oscillations in underdoped cuprate superconductors

Magneto-oscillations in kinetic and magnetic response functions of a few underdoped cuprates are perhaps one of the most striking observations since many probes of underdoped cuprates clearly point to a non Fermi-liquid normal state. Their observation in the vortex state well below the upper critical field raises a doubt concerning their normal state origin. Here I propose an explanation of the magneto-oscillations as emerging from the quantum interference of the vortex lattice and checkerboard modulations of the electron density of states revealed by STM with atomic resolution in some cuprate superconductors. The checkerboard effectively pins the vortex lattice, when the period of the latter is commensurate with the period of the checkerboard. This condition yields 1/\sqrt{B} periodicity of the response functions versus magnetic field B, rather than 1/B periodicity of conventional normal state oscillations. Our solution of the Gross-Pitaevskii-type equation for composed charged bosons accounting for the d-wave symmetry of the order-parameter and its checkerboard modulations describes well changes in resonant frequency of the tunnel-diode oscillator circuit with YBa2Cu4O8 and the oscillatory part of the Hall resistance and magnetic susceptibility in the mixed state of YBa2Cu3O6.5.Comment: 4 pages, 3 figures, experimental conditions allowing for a resolution of conventional normal-state and unconventional vortex-state magneto-oscillations are outline