Bacteria belonging to the Rhodococcus genus are frequent components of microbial communities in diverse natural environments. Some rhodococcal species exhibit the outstanding ability to produce ...significant amounts of triacylglycerols (TAG) (>20% of cellular dry weight) in the presence of an excess of the carbon source and limitation of the nitrogen source. For this reason, they can be considered as oleaginous microorganisms. As occurs as well in eukaryotic single-cell oil (SCO) producers, these bacteria possess specific physiological properties and molecular mechanisms that differentiate them from other microorganisms unable to synthesize TAG. In this review, we summarized several of the well-characterized molecular mechanisms that enable oleaginous rhodococci to produce significant amounts of SCO. Furthermore, we highlighted the ability of these microorganisms to degrade a wide range of carbon sources coupled to lipogenesis. The qualitative and quantitative oil production by rhodococci from diverse industrial wastes has also been included. Finally, we summarized the genetic and metabolic approaches applied to oleaginous rhodococci to improve SCO production. This review provides a comprehensive and integrating vision on the potential of oleaginous rhodococci to be considered as microbial biofactories for microbial oil production.
The first joint European Society for Medical Oncology (ESMO), European SocieTy for Radiotherapy & Oncology (ESTRO) and European Society of Gynaecological Oncology (ESGO) consensus conference on ...endometrial cancer was held on 11–13 December 2014 in Milan, Italy, and comprised a multidisciplinary panel of 40 leading experts in the management of endometrial cancer. Before the conference, the expert panel prepared three clinically relevant questions about endometrial cancer relating to the following four areas: prevention and screening, surgery, adjuvant treatment and advanced and recurrent disease. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, the panel developed recommendations for each specific question and a consensus was reached. Results of this consensus conference, together with a summary of evidence supporting each recommendation, are detailed in this article. All participants have approved this final article.
Until now, nonnative plant species were rarely found at high elevations and latitudes. However, partly because of climate warming, biological invasions are now on the rise in these extremely cold ...environments. These plant invasions make it timely to undertake a thorough experimental assessment of what has previously been holding them back. This knowledge is key to developing efficientmanagement of the increasing risks of cold-climate invasions. Here, we integrate human interventions (i.e., disturbance, nutrient addition, and propagule input) and climatic factors (i.e., temperature) into one seed-addition experiment across two continents: the subantarctic Andes and subarctic Scandinavian mountains (Scandes), to disentangle their roles in limiting or favoring plant invasions. Disturbance was found as the main determinant of plant invader success (i.e., establishment, growth, and flowering) along the entire cold-climate gradient, explaining 40–60% of the total variance in our models, with no indication of any facilitative effect from the native vegetation. Higher nutrient levels additionally stimulated biomass production and flowering. Establishment and flowering displayed a hump-shaped response with increasing elevation, suggesting that competition is the main limit on invader success at low elevations, as opposed to low-growing-season temperatures at high elevations. Our experiment showed, however, that nonnative plants can establish, grow, and flower well above their current elevational limits in high-latitude mountains. We thus argue that cold-climate ecosystems are likely to see rapid increases in plant invasions in the near future as a result of a synergistic interaction between increasing human-mediated disturbances and climate warming.
Real-time reverse transcription PCR (qPCR) normalized to an internal reference gene (RG), is a frequently used method for quantifying gene expression changes in neuroscience. Although RG expression ...is assumed to be constant independent of physiological or experimental conditions, several studies have shown that commonly used RGs are not expressed stably. The use of unstable RGs has a profound effect on the conclusions drawn from studies on gene expression, and almost universally results in spurious estimation of target gene expression. Approaches aimed at selecting and validating RGs often make use of different statistical methods, which may lead to conflicting results. Based on published RG validation studies involving hypoxia the present study evaluates the expression of 5 candidate RGs (Actb, Pgk1, Sdha, Gapdh, Rnu6b) as a function of hypoxia exposure and hypothermic treatment in the neonatal rat cerebral cortex-in order to identify RGs that are stably expressed under these experimental conditions-using several statistical approaches that have been proposed to validate RGs. In doing so, we first analyzed RG ranking stability proposed by several widely used statistical methods and related tools, i.e. the Coefficient of Variation (CV) analysis, GeNorm, NormFinder, BestKeeper, and the ΔCt method. Using the Geometric mean rank, Pgk1 was identified as the most stable gene. Subsequently, we compared RG expression patterns between the various experimental groups. We found that these statistical methods, next to producing different rankings per se, all ranked RGs displaying significant differences in expression levels between groups as the most stable RG. As a consequence, when assessing the impact of RG selection on target gene expression quantification, substantial differences in target gene expression profiles were observed. Altogether, by assessing mRNA expression profiles within the neonatal rat brain cortex in hypoxia and hypothermia as a showcase, this study underlines the importance of further validating RGs for each individual experimental paradigm, considering the limitations of the statistical methods used for this aim.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Surfactants are the most predominant contaminants in PRE sediments followed by PAHs.•Highest concentrations were found near Guangzhou city and Macao.•Wastewater discharges are a major source of ...contamination, except for UV filters.•Triisobutylphosphate and 2-ethylxheyldiphenylphospate are detected for the first time.•Legacy contaminants still pose a significant risk for the benthic communities at PRE.
This study focused on comparing the occurrences and environmental toxic risks for diverse priority and emerging contaminants (>100 chemicals) in the sediments from the Pearl River Estuary (PRE, China). The most predominant compounds were cationic surfactants, organophosphate flame retardants (e.g., triisobutylphosphate), and polycyclic aromatic hydrocarbons (PAHs), accounting for >75% of the total mass inventory (∼330 metric tons). Wastewater discharges seem to be one of the main sources of pollution in the area, as the highest concentrations (>1000ngg−1 for some chemicals) were reported in the upper part of the PRE (near Guangzhou city) and Macau. Highest levels of ultraviolet (UV) filters, however, were observed in recreational areas, revealing the importance of direct sources (e.g., outdoor activities). An environmental risk assessment showed that PAHs and dichlorodiphenyl dichloroethylene had the highest hazard quotient (HQ) values (up to 233). Nonylphenol, a metabolite from nonionic surfactant, and two UV filters (2-ethyl-hexyl-4-trimethoxycinnamate and 4-methylbenzylidene camphor) also posed a significant threat to benthic species (HQ>1). Further research through the realization of monitoring campaigns and toxicity tests is encouraged, as the exposure of the resident aquatic organisms and human population to these and other emerging chemicals is expected to increase over the years.
In this study, we have evaluated the occurrence and distribution of 78 pharmaceuticals in different aquatic marine environments from the Gulf of Cadiz (SW Spain) for the first time. The obtained ...results revealed that pharmaceuticals were present in seawater at total concentrations ranging 61–2133 and 16–189ngL−1 in coastal and oceanic transects, respectively. Potential marine pollution hotspots were observed in enclosed or semi-enclosed water bodies (Cadiz Bay), showing concentrations that were one or two orders of magnitude higher than in the open ocean. The presence of these chemicals in local sewage treatment plants (STPs), one of the main contamination sources, was also assessed, revealing total concentrations of up to 23μgL−1 in effluents. PhACs with the highest detection frequencies and concentrations in the sampling region were analgesics and anti-inflammatories followed by antibiotics in the case of samples from Cadiz Bay or caffeine in oceanic seawater samples. Risk quotients, expressed as ratios between the measured environmental concentration (MEC) and the predicted no-effect concentrations (PNEC) were higher than 1 for two compounds (gemfibrozil and ofloxacin) in effluent of Jerez de la Frontera sewage treatment plant (STP). No high environmental risk was detected in both coastal and oceanic sampling areas, although the information available about the effects of these chemicals on marine biota is still very limited and negative effects on non-target species cannot be discarded.
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•Carbamazepine, furosemide and hydrochlorothiazide persisted during wastewater treatment.•Conservative behaviour along Guadalete Estuary was observed for specific PhACs.•5 out of 45 antibiotics were found in open sea transects at levels up to 5ngL−1.•Preliminary risk assessment shows that PhACs pose no risk in offshore waters.
Abstract
The guest star of AD 1181 is the only historical supernova of the past millennium that is without a definite counterpart. The previously proposed association with supernova remnant ...G130.7+3.1 (3C 58) is in strong doubt because of the inferred age of this remnant. Here we report a new identification of SN 1181 with our codiscovery of the hottest known Wolf–Rayet star of the oxygen sequence (IRAS 00500+6713 or 2MASS J00531123+6730023, here named by us as “Parker's star”) and its surrounding nebula Pa 30. Our spectroscopy of the nebula shows a fast shock with extreme velocities of ≈1100 km s
−1
. The derived expansion age of the nebula implies an explosive event ≈1000 yr ago that agrees with the 1181 event. The on-sky location also fits the historical Chinese and Japanese reports of SN 1181 to within 3.°5. Pa 30 and Parker’s star have previously been proposed to be the result of a double-degenerate merger, leading to a rare Type Iax supernova. The likely historical magnitude and the distance suggest the event was subluminous for normal supernova. This agrees with the proposed Type Iax association that would also be only the second of its kind in the Galaxy. Taken together, the age, location, event magnitude, and duration elevate Pa 30 to prime position as the counterpart of SN 1181. This source is the only Type Iax supernova where detailed studies of the remnant star and nebula are possible. It provides strong observational support for the double-degenerate merger scenario for Type Iax supernovae.
The magneto-optical activity, namely the polarization conversion capabilities of high-index, non-absorbing, core-shell dielectric nanospheres is theoretically analyzed. We show that, in analogy with ...their plasmonic counterparts, the polarization conversion in resonant dielectric particles is linked to the amount of electromagnetic field probing the magneto-optical material in the system. However, in strong contrast with plasmon nanoparticles, due to the peculiar distribution of the internal fields in resonant dielectric spheres, the magneto-optical response is fully governed by the magnetic (dipolar and quadrupolar) resonances with little effect of the electric ones.
The occurrence of NADP
-dependent malic enzymes (NADP
-MEs) in several Rhodococcus strains was analysed. The NADP
-ME number in Rhodococcus genomes seemed to be a strain-dependent property. Total ...NADP
-ME activity increased by 1.8- and 2.6-fold in the oleaginous Rhodococcus jostii RHA1 and Rhodococcus opacus PD630 strains during cultivation under nitrogen-limiting conditions. Total NADP
-ME activity inhibition by sesamol resulted in a significant decrease of the cellular biomass and lipid production in oleaginous rhodococci. A non-redundant ME coded by the RHA1_RS44255 gene located in a megaplasmid (pRHL3) of R. jostii RHA1 was characterized and its heterologous expression in Escherichia coli resulted in a twofold increase in ME activity in an NADP
-dependent manner. The overexpression of RHA1_RS44255 in RHA1 and PD630 strains grown on glucose promoted an increase in total NADP
-ME activity and an up to 1.9-foldincrease in total fatty acid production without sacrificing cellular biomass. On the other hand, its expression in Rhodococcus fascians F7 grown on glycerol resulted in a 1.3-1.4-foldincrease in total fatty acid content. The results of this study confirmed the contribution of NADP
-MEs to TAG accumulation in oleaginous rhodococci and the utility of these enzymes as an alternative approach to increase bacterial oil production from different carbon sources.
Real space bonding descriptors are orbital invariant indices that can be obtained independently of the theoretical framework used to compute a given wavefunction. Here we show how to use them to read ...in real space some widely used concepts in Valence Bond (VB) theory, such as ionic/covalent characters or covalent-ionic resonance energies. All of these are essential ingredients used when building VB chemical insight. Electron number distribution functions are employed to directly map ionic and covalent weights with real space delocalization indices. We show that covalency, understood as delocalization, emerges in position space from the fluctuation of electron populations. This is mapped in VB to covalent-ionic resonance. The reasons why this is not so in the standard language of non-orthogonal VB are examined. A simple real space ionic character index that maintains the essence of its VB equivalent is defined and examined in simple model systems. The conclusions of this work ease travelling among the sometimes conflicting molecular orbital, real space, and valence bond interpretations in chemical bonding theory.
Real space bonding descriptors are orbital invariant indices that can be obtained independently of the theoretical framework used to compute a given wavefunction.
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