Isolasi Identifikasi Bakteri Penghasil Xilanase Serta Karakterisasi Enzimnya

Xylanase is an extracellular enzyme produced bymicroorganisms. This enzyme is able to hydrolise xylane(hemicellulose) to produce xylooligosaccharide and xylose.Thermoalkaliphilic xylanase is an agent that can be used asa substitute in the pulp whitening process instead of chlorine.A study was done to isolate, identificate of bacteria andcharacterize xylanase. The isolation of xylanase producingbacteria has been done from soil and waste of starch industry.Colonies which produced clearing zone were presumedas xylanolytic bacteria and chosen for further screening.Identification of potential isolate in xylanase production wasdone using 16S ribosomal RNA sequencing. Isolate Bacilluspumilus RXA-III5 originated from lime or alkaline soil wasmore potential isolate in xylanase production than other 24isolates. Precipitation of xylanase, that was done usingammonium sulphate followed by dialyzes produced xylanaseof a higher specific activity (267.1 U.mg-1) than that usingacetone (131.1 U.mg-1) and ethanol (186.65 U.mg-1). Xylanasewas done at purification produced three fractions of xylanase.Xylanase characteristics consist of pH and temperature(9 and 50oC), Km and Vmaks value 6 mg.ml-1 and 0.2mol.minute-1, respectively. The Fe2+ was the strongest activetorand Mg2+ was the strongest inhibitor activity. This enzymewas detected as a cellulose-free xylanase. Xylanase is aprospective agent for bio-bleaching of paper

Dynamical Properties of a Haldane Gap Antiferromagnet

We study the dynamic spin correlation function of a spin one antiferromagnetic chain with easy-plane single-ion anisotropy. We use exact diagonalization by the Lancz\H os method for chains of lengths up to N=16 spins. We show that a single-mode approximation is an excellent description of the dynamical properties. A variational calculation allows us to clarify the nature of the excitations. The existence of a two-particle continuum near zero wavevector is clearly seen both in finite-size effects and in the dynamical structure factor. The recent neutron scattering experiments on the quasi-one-dimensional antiferromagnet NENP are fully explained by our results.Comment: 14 pages, SphT/92-135 plain tex with Postscript figures included. Postscipt file available by anonymous ftp at amoco.saclay.cea.fr by get pubs.spht/92-135.ps local_file (290 kb) or get pubs.spht/92-135.ps.Z local_file.Z (compressed - 120 kb

From model-driven software development processes to problem diagnoses at runtime

Following the “convention over configuration” paradigm, model-driven software development (MDSD) generates code to implement the “default” behaviour that has been specified by a template separate from the input model. On the one hand, developers can produce end-products without a full understanding of the templates; on the other hand, the tacit knowledge in the templates is subtle to diagnose when a runtime software failure occurs. Therefore, there is a gap between templates and runtime adapted models. Generalising from the concrete problematic examples in MDSD processes to a model-based problem diagnosis, the chapter presents a procedure to separate the automated fixes from those runtime gaps that require human judgments

An electrochemical impedance study of the effect of pathogenic bacterial toxins on tethered bilayer lipid membrane

Pathogenic bacteria secrete various virulence factors that can directly interact with the outer lipid bilayer membrane of eukaryotic cells, inducing cell death by apoptosis or necrosis. Such virulence factors account for much of the toxic action associated with bacterial infection; therefore the detection of such proteins could provide a methodology for sensing/detection of pathogenic bacteria in, for example, food or human tissue. Detection and identification of pathogenic bacteria by conventional methods such as plating and counting in laboratory is expensive and time consuming. With growing concerns over emergence and re-emergence of pathogenic bacteria with high resistant to current antibiotics, there is a potential need for effective detection of pathogenic toxins in-vitro. This paper presents the application of tethered bilayer lipid membrane (TBLM) as a sensing platform for the detection of the clinically relevant pathogenic bacterial, Staphylococcus aureus MSSA 476 and Pseudomonas aeruginosa PAO1 via their secreted virulence factors, using electrochemical impedance spectroscopy (EIS). A non-pathogenic strain of bacteria, E. coli DH5α was used as a control. A clear difference in the impedance of the TBLM for the pathogenic vs. non-pathogenic species was observed. Keywords: Pathogenic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Pore-forming toxins, Electrochemical impedance spectroscop

Late-onset X-linked adrenal hypoplasia (DAX-1, NR0B1): two new adult-onset cases from a single center

PURPOSE: DAX-1 (NR0B1) is an orphan nuclear receptor, which plays a critical role in development and regulation of the adrenal gland and hypothalamo-pituitary-gonadal axis. Mutations in NR0B1 lead to adrenal hypoplasia congenita (AHC), hypogonadotropic hypogonadism (HH) and azoospermia in men. Presentation is typically with adrenal insufficiency (AI) during infancy or childhood. To date only eight cases/kindreds are reported to have presented in adulthood. METHODS: We describe two new cases of men with DAX-1 mutations who presented in adulthood and who were diagnosed at a large University Hospital. RESULTS: Case 1 presented with AI at 19 years. At 38 years he was diagnosed with HH. Detailed history revealed a brother diagnosed with AI at a similar age. Sequencing of the DAX-1 (NR0B1) gene revealed a heterozygous c.775T > C substitution in exon 1, which changes codon 259 from serine to proline (p.Ser259Pro). Case 2 was diagnosed with AI at 30 years. Aged 37 years he presented with HH and azoospermia. He was treated with gonadotropin therapy but remained azoospermic. Testicular biopsy showed maturational arrest and hypospermatogenesis. Analysis of the NR0B1 gene showed a heterozygous c.836C > T substitution in exon 1, resulting in a change of codon 279 from proline to leucine (p.Pro279Leu). This change alters the structure of the repression helix domain of DAX-1 and affects protein complex interactions with NR5A family members. CONCLUSIONS: We describe two missense mutations within the putative carboxyl-terminal ligand binding domain of DAX-1, presenting with AHC and HH in adulthood, from a single center. DAX-1 mutations may be more frequent in adults than previously recognized. We recommend testing for DAX-1 mutations in all adults with primary AI and HH or impaired fertility where the etiology is unclear

Field- and pressure-induced magnetic quantum phase transitions in TlCuCl_3

Thallium copper chloride is a quantum spin liquid of S = 1/2 Cu^2+ dimers. Interdimer superexchange interactions give a three-dimensional magnon dispersion and a spin gap significantly smaller than the dimer coupling. This gap is closed by an applied hydrostatic pressure of approximately 2kbar or by a magnetic field of 5.6T, offering a unique opportunity to explore the both types of quantum phase transition and their associated critical phenomena. We use a bond-operator formulation to obtain a continuous description of all disordered and ordered phases, and thus of the transitions separating these. Both pressure- and field-induced transitions may be considered as the Bose-Einstein condensation of triplet magnon excitations, and the respective phases of staggered magnetic order as linear combinations of dimer singlet and triplet modes. We focus on the evolution with applied pressure and field of the magnetic excitations in each phase, and in particular on the gapless (Goldstone) modes in the ordered regimes which correspond to phase fluctuations of the ordered moment. The bond-operator description yields a good account of the magnetization curves and of magnon dispersion relations observed by inelastic neutron scattering under applied fields, and a variety of experimental predictions for pressure-dependent measurements.Comment: 20 pages, 17 figure

Risk factor-based screening compared to universal screening for gestational diabetes mellitus in marginalized Burman and Karen populations on the Thailand-Myanmar border: an observational cohort

Background: Gestational diabetes mellitus (GDM) contributes significantly to maternal and neonatal morbidity, but data from marginalized populations remains scarce. This study aims to compare risk-factor-based screening to universal testing for GDM among migrants along the Thailand-Myanmar border. Methods: From the prospective cohort (September 2016, February 2019), 374 healthy pregnant women completed a 75g oral glucose tolerance test (OGTT) at 24-32 weeks gestation. Fasting, one hour and two hour cut-offs were based on Hyperglycaemia and Adverse Pregnancy Outcomes (HAPO trial) criteria and cases were treated. The sensitivity and specificity of risk-factor-based screening criteria was calculated using OGTT as the gold standard. Risk factors included at least one positive finding among 10 criteria, e.g., obesity (body mass index (BMI) >/=27.5kg/m (2)), 1 (st) degree relative with diabetes etc. Adverse maternal and neonatal outcomes were compared by GDM status, and risk factors for GDM were explored. Results: GDM prevalence was 13.4% (50/374) (95% CI: 10.3-17.2). Risk-factors alone correctly identified 74.0% (37/50) OGTT positive cases: sensitivity 74.0% (59.7-85.4) and specificity 27.8% (3.0-33.0). Burman women accounted for 29.1% of the cohort population, but 38.0% of GDM cases. Percentiles for birthweight (p=0.004), head circumference (p=0.005), and weight-length ratio (p=0.010) were higher in newborns of GDM mothers compared with non-GDM, yet 21.7% (75/346) of newborns in the cohort were small-for-gestational age. In Burman women, overweight/obese BMI was associated with a significantly increased adjusted odds ratio 5.03 (95% CI: 1.43-17.64) for GDM compared to normal weight, whereas underweight and overweight/obese in Karen women were both associated with similarly elevated adjusted odds, approximately 2.4-fold (non-significant) for GDM. GDM diagnosis by OGTT was highest prior to peak rainfall. Conclusions: Risk-factor-based screening was not sufficiently sensitive or specific to be useful to diagnose GDM in this setting among a cohort of low-risk pregnant women. A two-step universal screening program has thus been implemented

Spin-Wave Description of Haldane-gap antiferromagnets

Modifying the conventional antiferromagnetic spin-wave theory which is plagued by the difficulty of the zero-field sublattice magnetizations diverging in one dimension, we describe magnetic properties of Haldane-gap antiferromagnets. The modified spin waves, constituting a grand canonical bosonic ensemble so as to recover the sublattice symmetry, not only depict well the ground-state correlations but also give useful information on the finite-temperature properties.Comment: to be published in J. Phys. Soc. Jpn. Vol. 72, No. 4 (2003