Estudio de la regulación por la luz azul en Phycomyces blakesleeanus

[ES] La razón principal de la presencia de Phycomyces en los laboratorios es su sensibilidad a la luz, descubierta hace cerca de 150 años. Desde entonces se han desarrollado técnicas que permiten su manipulación genética y bioquímica. Phycomyces fue el primer organismo en el que se investigaron mutantes espontáneos y el segundo, después de Drosophila, en el que se indujeron mutaciones artificialmente. En Phycomyces no se conocen diploides estables y la presencia de dos genomas en una misma célula se consigue mediante heterocariosis. El término heterocarionte (células con núcleos genéticamente diferentes) fue acumulado por Burgeff en 1914, aunque fue descrito por primera vez por Blakeslee en 1906, iniciadores éstos del desarrollo de la genética de Phycomyces. Mediante el uso de heterocariontes es posible realizar las pruebas de complementación y también la llamada complementación cuantitativa, técnica en la que cada micelio heterocariótico es analizado fenotípicamente y genéticamente para relacionar la proporción nuclear de ambos núcleos en el heterocarionte y una determinada función. Con este método se ha profundizado mucho en el estudio de la biosíntesis de carotenoides y su regulación, así como en el estudio de algunas propiedades del fototropismo.El contraste entre la relativa simplicidad del hongo Phycomyces, cuyo esporangióforo presenta unas pautas de crecimiento muy bien definidas, y la relativa complejidad de sus reacciones a gran variedad de estímulos ambientales, atrajo la atención de varios grupos de investigación en el siglo XIX. Posteriormente, el gran impulsor de las investigaciones en Phycomyces para tratar de entender los mecanismos de sensibilidad y comportamiento celulares fue Max Delbrück, que abandonó sus estudios con los fagos, por los cuales obtuvo junto con Luria y Hershey el Premio Nobel en 1969, y se dedicó al estudio de Phycomyces como sistema modelo para tratar de ver las bases moleculares de la captación de la información externa (información ambiental), su procesamiento y elaboración de mecanismos de respuesta

THE CURATIVE ROLE OF BITUMEN IN TRADITIONAL PERSIAN MEDICINE

Aim: Bitumen is a natural substance effusing from rocks’ notches in some highland areas; it has been known as an effective remedy for treating some illnesses. Considering pain relieving properties of bitumen in traditional Persian medicine (TPM) sources, this study aims to review the viewpoints of TPM sages regarding bitumen in the context of traditional Persian medicine. It also provides applicable information for interested researchers to conduct well-designed clinical trials and evaluate therapeutic effects of bitumen claimed in TPM sources. Material and method: Various databases including Embase, SID, IRANDOC, IranMedex, Scopus and PubMed were searched with keywords “bitumen” and “Shilajit”. Furthermore, main traditional Persian medicine sources including Avicenna’s “Canon of medicine”, “Continens Liber” by Razes, “The storehouse of medicaments” by Aghili, “Gift for the faithful” by Momen Tonekaboni and “Measure for medicine” written by Muhammad Akbar Shah Arzani were reviewed with Persian keywords “Moomiaii” and “Mumnaei”. Results: According to TPM sources, bitumen was used by Iranian’s physicians to treat a wide range of diseases. It was known especially as an effective remedy to improve gastrointestinal digestive problems. Conclusion: Bitumen is cited in traditional Persian medicine sources as an effective remedy for treatment of a wide range of diseases, especially GI disorders and bone pain. Recent studies showed the beneficial effects of bitumen in treatment of wound healing, however using it in medical practice for other health dilemma should be confirmed by conducting well-designed clinical studies in the future

MYCN Gene Copy Number Status Detected by FISH Method and Its Correlation with Outcome and Clinicopathological Variables in Childhood Neuroblastoma

Background: Neuroblastoma is the most common extracranial solid tumor in children. MYCN gene amplification (MNA) is an independent prognostic factor for rapid tumor progression and poor prognosis, regardless of age and clinical stage. Gain of the MYCN gene locus on the short arm of chromosome 2 can also be found in neuroblastoma.Method: In this retrospective descriptive analysis of genetic alterations in neuroblastoma tumor samples, both before and after standard chemotherapy, we examined the MYCN gene copy number status in 20 neuroblastic tumor samples using the fluorescence in situ hybridization (FISH) method. We also evaluated its relationship with clinical variables and tumor maturation after standard chemotherapy treatment. Additionally, we compared disease outcomes among different MYCN copy number categories.Results: Among the tumor samples, four (25%) exhibited increased MYCN copy numbers, 20% showed MYCN amplification, and 5% displayed MYCN gain. We observed decreased survival rates in advanced stages of neuroblastoma. Furthermore, in male patients, we noted an association between increased MYCN copy number and metastatic tumors.Conclusion: We found that increased MYCN copy number is moderately associated with an immature phenotype and correlated with lower event-free survival. However, we did not detect a statistically significant difference

Determination of Lipid Profile in Preschool Children and Pre- college Students with Beta-thalassemia Minor and Control Group

Thalassemias are heterogeneous group of inherited anemias caused by various mutations in the genes encoding the synthesis of α α α α α or β β β β β-chains of hemoglobin. It seems that there are some aspects in thalassemia that protect minor thalassemic patients from coronary heart disease. From those aspects we can count such as low serum lipoproteins, low arterial hypertension, and anemia and so on. A cross sectional descriptive and analytical study was designed to compare some lab data of minor thalassemic students and others. So 570 preschool children (6-7 years of age) and 450 pre-college students (17-19 year of age) in 4 educational discrete of Shiraz (center of Fars province-Iran) were selected in a random cluster manner were tested for CBC and serum lipids (TG, cholesterol, LDL, HDL) and were screened for minor thalassemia by CBC and HbA 2 (by column chromatography). For definition of minor thalassemia as cut-off Point HbA 2 ≥ ≥ ≥ ≥ ≥ 3.5% was accepted. After selection of minor thalassemic patients, serum lipids (TG, cholesterol, HDL, LDL) for them and control group were checked. According to this study in preschool children there is no significant difference between minor thalassemic patients and control group. In pre-collage students TG in control group is lesser than minor beta thalassemic patients (P value=0.004); but total cholesterol and LDL in patients group is lesser than control group and difference is significant. Total cholesterol and LDL in pre-college beta thalassemia minor students are lesser than control group. But TG in control group is lesser than patients group. According to this study in preschool children there is no significant difference in serum lipids between minor thalassemic students and control group

Dependence of thermal diffusivity on particle size in Au nano-fluid

In this paper we report the measurement of thermal diffusivity of gold nanofluid prepared by γ-radiation with various particle sizes ranging from 7.0 nm to 18.7 nm. The thermal lens technique is used to measure thermal diffusivity of gold nano-fluid. In this technique a diode laser (wavelength 514 nm, power 80 mW) and He-Ne laser were used as the excitation source and probe beam respectively. Experimental results showed that thermal diffusivity values of nanofluid increase when the particle size increase

Optimization of cellulase production by Aspergillus terreus under submerged fermentation using response surface methodology

Oil palm empty fruit bunch (OPEFB) is one of the most important wastes from the oil palm industry which can be treated and utilized as a main carbon source in fermentation. The ability of newly isolated Aspergillus terreus to produce cellulases in submerged fermentation with OPEFB fibre as carbon source was investigated. Response surface methodology based on central composite design (CCD) was chosen to optimize the composition of four medium constituents viz, OPEFB fibers (5-15 g/L), yeast extract (3-9 g/L), CaCl2 (1-5 mM), MgSO4 (3-7mM) and to optimize the level of two environmental condition agitation speed (200-300 rpm) and temperature (28-32°C). A second order model was proposed to assess the effect of these 6 variables. Based on the proposed model, the optimized conditions for the maximum cellulase production was 13.90 g/L OPEFB fiber, 8 g/L yeast extract, 3.5 mM CaCl2, 7 mM of MgSO4, 225 rpm of agitation and 29°C temperature. The optimized values obtained by the statistical analysis gave 14.25U/ml of CMCase, 1.13 U/ml of FPase, and 9.86 U/ml of β-glucosidase and 5.2 g/l of Cell concentration. In fermentation using the optimized conditions, the fungi cell concentration, CMCase, FPase and β-glucosidase activity was 5.2 g/l, 14.25 U/ml, 1.13 U/ml and 9.86 U/ml, respectively

A Ras GTPase associated protein is involved in the phototropic and circadian photobiology responses in fungi

[EN] Light is an environmental signal perceived by most eukaryotic organisms and that can have major impacts on their growth and development. The MadC protein in the fungus Phycomyces blakesleeanus (Mucoromycotina) has been postulated to form part of the photosensory input for phototropism of the fruiting body sporangiophores, but the madC gene has remained unidentified since the 1960s when madC mutants were first isolated. In this study the madC gene was identified by positional cloning. All madC mutant strains contain loss-of-function point mutations within a gene predicted to encode a GTPase activating protein (GAP) for Ras. The madC gene complements the Saccharomyces cerevisiae Ras-GAP ira1 mutant and the encoded MadC protein interacts with P. blakesleeanus Ras homologs in yeast two-hybrid assays, indicating that MadC is a regulator of Ras signaling. Deletion of the homolog in the filamentous ascomycete Neurospora crassa affects the circadian clock output, yielding a pattern of asexual conidiation similar to a ras-1 mutant that is used in circadian studies in N. crassa. Thus, MadC is unlikely to be a photosensor, yet is a fundamental link in the photoresponses from blue light perceived by the conserved White Collar complex with Ras signaling in two distantly-related filamentous fungal species

Expansion of Signal Transduction Pathways in Fungi by Extensive Genome Duplication

International audienceno abstrac

Expansion of Signal Transduction Pathways in Fungi by Extensive Genome Duplication

[EN] Plants and fungi use light and other signals to regulate development, growth, and metabolism. The fruiting bodies of the fungus Phycomyces blakesleeanus are single cells that react to environmental cues, including light, but the mechanisms are largely unknown [1]. The related fungus Mucor circinelloides is an opportunistic human pathogen that changes its mode of growth upon receipt of signals from the environment to facilitate pathogenesis [2]. Understanding how these organisms respond to environmental cues should provide insights into the mechanisms of sensory perception and signal transduction by a single eukaryotic cell, and their role in pathogenesis. We sequenced the genomes of P. blakesleeanus and M. circinelloides and show that they have been shaped by an extensive genome duplication or, most likely, a whole-genome duplication (WGD), which is rarely observed in fungi [3-6]. We show that the genome duplication has expanded gene families, including those involved in signal transduction, and that duplicated genes have specialized, as evidenced by differences in their regulation by light. The transcriptional response to light varies with the developmental stage and is still observed in a photoreceptor mutant of P. blakesleeanus. A phototropic mutant of P. blakesleeanus with a heterozygous mutation in the photoreceptor gene madA demonstrates that photosensor dosage is important for the magnitude of signal transduction. We conclude that the genome duplication provided the means to improve signal transduction for enhanced perception of environmental signals. Our results will help to understand the role of genome dynamics in the evolution of sensory perception in eukaryotes.European funds (European Regional Development Fund, ERDF); Spanish Ministerio de Economı´a y Competitividad; Junta de Andalucí

Thrombocytopenia and Unexplained Splenomegaly; The Role of Hematologists in the Early Diagnosis of Gaucher Disease

Hematologists should consider the diagnosis of Gaucher disease; when they look for the cause of unexplained splenomegaly and thrombocytopenia. In countries which consanguineous marriage is prevalent, autosomal recessive disorders like Gaucher Disease may be seen frequently. The diagnosis can be done today by a simple blood test, so liver biopsy is not necessary. BM aspiration and biopsy may be needed for exclusion of other diagnoses and can be deferred until report of enzyme assay. Genetic study is needed for definite diagnosis.</p