The distribution and diversity of actinomycetes in soil fractions

The results presented were concerned with the survival of Streptomyces coelicolor A3(2) (pll673) inoculated into soil microcosms, which were destructively fractionated so that the total propagules and spore counts could be determined in each of the soil fractions. It was found that this microorganism became associated with the smallest soil aggregates at the time of inoculation but with incubation of the soil microcosms the mycelia and spores became attached to the larger soil aggregates. In the sterile soil, the streptomycete growth was much greater than in nonsterile soil, perhaps due to the increased supply of nutrients created by autoclaving the soil, and the lack of competition. Many of the newly formed spores in sterile soil were not attached to the soil aggregates, which may have enabled them to be distributed to new micro sites. When the distribution of indigenous actinomycetes in soil was investigated, it ressembled the distribution of Streptomyces coelicolor in nonsterile soil after the inoculant had been through one life cycle. Actinomycetes were then isolated from each of the soil fractions, as well as the unfractionated soil, and each of these strains were identified to genera, if possible. It was found that many of the micromonosporas and streptosporangia were isolated from the 63-251 μm soil aggregates, probably because this fraction contained low eubacterial and streptomycetes populations caused by the low organic content within this soil fraction. There was a high eubacterial count in the 2-20 μm soil aggregates and although the actinomycetes were outcompeted within this soil fraction, their diversity was greatest within this fraction. This diversity was also reflected by their production of different secondary metabolites. DNA was extracted from each of the isolates and amplified using specifically designed primers for high GC microorganisms. Each of the products were individually run on denaturing gradient gels. It was found that the amplified products from actinomycetes formed bands on the denaturing gels which migrated to 3 positions. Each of these positions corresponded to major groups of actinomycetes of which streptomycetes formed one group. The patterns corresponding to the isolates of each soil fraction would be compared with the amplified products derived from in situ soil DNA extracts. It was found that the results were not comparable but this work is still being investigated

[5-Hydroxy-3-phenyl-1-(pyridin-2-yl)pyrazol-5-olato]diphenylboron

In the title compound, C26H20BN3O, the B atom has tetra­hedral geometry and is linked to two phenyl rings, the O atom of the hy­droxy­pyrazole ring and the N atom of the pyridinyl ring. A six-membered BOCNCN ring forms by coordination of the B atom and the pyridinyl N atom. The BOCNCN ring has an envelope conformation [dihedral angle = 36.7 (1)° between the planar ring atoms and the flap] with the B atom out of the plane. In the 1-(2-pyridin­yl)-3-phenyl-5-hy­droxy­pyrazole group, the pyridinyl ring, the phenyl ring and the pyrazole ring are almost coplanar: the pyrazole ring makes a dihedral angle of 9.56 (8)° with the pyridinyl ring and 17.68 (7)° with the phenyl ring. The crystal structure is stabilized by π–π stacking inter­actions involving the pyridinyl and pyrazole rings of centrosymmetrically related mol­ecules, with ring centroid separations of 3.54 (5) Å

Integrative analysis identifies candidate tumor microenvironment and intracellular signaling pathways that define tumor heterogeneity in NF1

Neurofibromatosis type 1 (NF1) is a monogenic syndrome that gives rise to numerous symptoms including cognitive impairment, skeletal abnormalities, and growth of benign nerve sheath tumors. Nearly all NF1 patients develop cutaneous neurofibromas (cNFs), which occur on the skin surface, whereas 40-60% of patients develop plexiform neurofibromas (pNFs), which are deeply embedded in the peripheral nerves. Patients with pNFs have a ~10% lifetime chance of these tumors becoming malignant peripheral nerve sheath tumors (MPNSTs). These tumors have a severe prognosis and few treatment options other than surgery. Given the lack of therapeutic options available to patients with these tumors, identification of druggable pathways or other key molecular features could aid ongoing therapeutic discovery studies. In this work, we used statistical and machine learning methods to analyze 77 NF1 tumors with genomic data to characterize key signaling pathways that distinguish these tumors and identify candidates for drug development. We identified subsets of latent gene expression variables that may be important in the identification and etiology of cNFs, pNFs, other neurofibromas, and MPNSTs. Furthermore, we characterized the association between these latent variables and genetic variants, immune deconvolution predictions, and protein activity predictions

Restless quiescence: thermonuclear flashes between transient X-ray outbursts

For thermonuclear flashes to occur on neutron-star surfaces, fuel must have been accreted from a donor star. However, sometimes flashes are seen from transient binary systems when they are thought to be in their quiescent phase, during which no accretion, or relatively little, is expected to occur. We investigate the accretion luminosity during several such flashes, including the first-ever and brightest detected flash from Cen X-4 in 1969. We infer from observations and theory that immediately prior to these flashes the accretion rate must have been between about 0.001 and 0.01 times the equivalent of the Eddington limit, which is roughly 2 orders of magnitude less than the peak accretion rates seen in these transients during an X-ray outburst and 3-4 orders of magnitude more than the lowest measured values in quiescence. Furthermore, three such flashes, including the one from Cen X-4, occurred within 2 to 7 days followed by an X-ray outburst. A long-term episode of enhanced, but low-level, accretion is predicted near the end of the quiescent phase by the disk-instability model, and may thus have provided the right conditions for these flashes to occur. We discuss the possibility of whether these flashes acted as triggers of the outbursts, signifying a dramatic increase in the accretion rate. Although it is difficult to rule out, we find it unlikely that the irradiance by these flashes is sufficient to change the state of the accretion disk in such a dramatic way.Comment: 9 pages, 3 figures, accepted for publication in A&A; referee comments included plus improved text; results unchange

Hyperbolic entire functions and the Eremenko–Lyubich class: Class B or not class B?

Hyperbolicity plays an important role in the study of dynamical systems, and is a key concept in the iteration of rational functions of one complex variable. Hyperbolic systems have also been considered in the study of transcendental entire functions. There does not appear to be an agreed definition of the concept in this context, due to complications arising from the non-compactness of the phase space. In this article, we consider a natural definition of hyperbolicity that requires expanding properties on the preimage of a punctured neighbourhood of the isolated singularity. We show that this definition is equivalent to another commonly used one: a transcendental entire function is hyperbolic if and only if its postsingular set is a compact subset of the Fatou set. This leads us to propose that this notion should be used as the general definition of hyperbolicity in the context of entire functions, and, in particular, that speaking about hyperbolicity makes sense only within the Eremenko–Lyubich classB of transcendental entire functions with a bounded set of singular values. We also considerably strengthen a recent characterisation of the class B, by showing that functions outside of this class cannot be expanding with respect to a metric whose density decays at most polynomially. In particular, this implies that no transcendental entire function can be expanding with respect to the spherical metric. Finally we give a characterisation of an analogous class of functions analytic in a hyperbolic domain

Male gender is an important clinical risk factor for iron deficiency in healthy infants

Author's personal copy ; Acknowledgements to the children and families who were involved in this study, and to BH Pathology Clinic Dpt.Background & aims: To identify ID risk factors in infancy, and try to explore why ID is more prevalent in boys than in girls in the first year of life. Methods: A multiple logistic regression was performed on data of 201 infants, with ferritin<12 ng/ml as the dependent variable and months of breastfeeding, weight gain from birth to 9 months (WG), and gender as independent variables. To compare haematological parameters we used Manne-Whitney and t test. Results: From the 39 infants with IDA (19.4%), 24 (61.5%) were male and of the 162 infants without IDA, 50% were male (p ¼ 0.195). The median(minimum; maximum) ferritin concentrations in male infants at 9 months was of 9.8 ng/ml (0.5e67.0 ng/ml) and in females 14 ng/ml (0.5e74.5 ng/ml), p < 0.001. The average (±SD) WG was of 5863.3 g (±855.4 g) in male infants and 5556.9 g (±1054.3 g) in female infants (p = 0.027). A multiple logistic regression (OR; 95%CI) showed that male gender was the most important risk factor (OR: 3.3; 1.7e6.3; p < 0.001), followed by a higher weight increase (OR: 1.6; CI [1.1; 2.2]; p = 0.016) and longer breastfeeding time (OR: 1.1; CI [0.98; 1.2]; p = 0.099). Comparison of other haematological parameters at 9 months in relation to gender (males (M): 105; females (F): 96) showed significant differences in: mean ± SD, Mean Corpuscular Haemoglobin (M: 25.0 ± 2.1; F: 25.8 ± 2.4 pg, p = 0.001), Mean Corpuscular Volume (M: 73.4 ± 4.1; F: 75.3 ± 4.2 fl, 0.009), RDW (M: 14.6 ± 1.5; F: 14.1 ± 1.6%, p = 0.048), Plaquelets (M: 324.9 ± 77.9; F: 350.5 ± 81.4 x 10³/µl, p = 0.026). Conclusions: ID was significantly more frequent in male infants, independent of rapid growth or longer breastfeeding duration. The clinical risk profile for ID in infants includes male gender and not only rapid growth, and longer breastfeeding duration.This study received a scholarship from the Foment Commission for Investigation in Health Care, from the Health Ministry P.I. nº 87/07

The triglyceride to high-density lipoprotein ratio identifies children who may be at risk of developing cardiometabolic disease

Aim: It is important to develop simple, reliable methods to identify high-risk individuals who may benefit from intervention. This study investigated the association between the triglyceride to high-density lipoprotein cholesterol (TG/HDL) ratio and cardiometabolic risk, cardiorespiratory fitness and physical activity in children. Methods: Anthropometric, biochemical parameters, cardiorespiratory fitness and accelerometry determined physical activity were assessed in 155 children (80 girls) from 10 to 14 years of age from Bedfordshire, UK. Participants were grouped into high and low TG/HDL ratio groups, according to published thresholds. MANCOVA and logistic regression were used in the analysis. Results: Cardiometabolic risk factor levels were significantly higher in participants with a high TG/HDL ratio (p < 0.05). The odds of having high waist circumference (OR = 13.99; 95% CI 2.93, 69.25), elevated systolic blood pressure (5.27; 1.39, 20.01), high non-HDL cholesterol (19.47; 4.42, 85.81) and ≥2 cardiometabolic risk factors (15.32; 3.10, 75.79) were higher in participants with a high TG/HDL ratio. The TG/HDL ratio values were significantly lower in those with high cardiorespiratory fitness (p = 0.01), but there was no association with physical activity. Conclusion: These findings support the use of the TG/HDL ratio to identify children with cardiometabolic risk factors who may be at risk of developing cardiometabolic disease

Escape rate and Hausdorff measure for entire functions

The escaping set of an entire function is the set of points that tend to infinity under iteration. We consider subsets of the escaping set defined in terms of escape rates and obtain upper and lower bounds for the Hausdorff measure of these sets with respect to certain gauge functions.Comment: 24 pages; some errors corrected, proof of Theorem 2 shortene