Gram-negative bacteria are surrounded by an inner cytoplasmic membrane and by an outer membrane, which serves as a protective barrier to limit entry of many antibiotics. The distinctive properties of ...the outer membrane are due to the presence of lipopolysaccharide
. This large glycolipid, which contains numerous sugars, is made in the cytoplasm; a complex of proteins forms a membrane-to-membrane bridge that mediates transport of lipopolysaccharide from the inner membrane to the cell surface
. The inner-membrane components of the protein bridge comprise an ATP-binding cassette transporter that powers transport, but how this transporter ensures unidirectional lipopolysaccharide movement across the bridge to the outer membrane is unknown
. Here we describe two crystal structures of a five-component inner-membrane complex that contains all the proteins required to extract lipopolysaccharide from the membrane and pass it to the protein bridge. Analysis of these structures, combined with biochemical and genetic experiments, identifies the path of lipopolysaccharide entry into the cavity of the transporter and up to the bridge. We also identify a protein gate that must open to allow movement of substrate from the cavity onto the bridge. Lipopolysaccharide entry into the cavity is ATP-independent, but ATP is required for lipopolysaccharide movement past the gate and onto the bridge. Our findings explain how the inner-membrane transport complex controls efficient unidirectional transport of lipopolysaccharide against its concentration gradient.
The possibility of detecting and classifying living cells in a label-free and non-invasive manner holds significant theranostic potential. In this work, Hyperspectral Imaging (HSI) has been ...successfully applied to the analysis of macrophagic polarization, given its central role in several pathological settings, including the regulation of tumour microenvironment. Human monocyte derived macrophages have been investigated using hyperspectral reflectance confocal microscopy, and hyperspectral datasets have been analysed in terms of M1 vs. M2 polarization by Principal Components Analysis (PCA). Following PCA, Linear Discriminant Analysis has been implemented for semi-automatic classification of macrophagic polarization from HSI data. Our results confirm the possibility to perform single-cell-level in vitro classification of M1 vs. M2 macrophages in a non-invasive and label-free manner with a high accuracy (above 98% for cells deriving from the same donor), supporting the idea of applying the technique to the study of complex interacting cellular systems, such in the case of tumour-immunity in vitro models.
The study and the characterization of cell death mechanisms are fundamental in cell biology research. Traditional death/viability assays usually involve laborious sample preparation and expensive ...equipment or reagents. In this work, we use electrical impedance spectroscopy as a label-free methodology to characterize viable, necrotic and apoptotic human lymphoma U937 cells. A simple three-electrode coplanar layout is used in a differential measurement scheme and thousands of cells are measured at high-throughput (≈200 cell/s). Tailored signal processing enables accurate and robust cell characterization without the need for cell focusing systems. The results suggest that, at low frequency (0.5 MHz), signal magnitude enables the discrimination between viable/necrotic cells and cell fragments, whereas phase information allows discriminating between viable cells and necrotic cells. At higher frequency (10 MHz) two subpopulations of cell fragments are distinguished. This work substantiates the prominent role of electrical impedance spectroscopy for the development of next-generation cell viability assays.
•Label-free cell viability assays are urgently needed in cell biology research.•We use a simple microfluidic impedance cytometer to study the viability of human lymphoma cells.•Tailored signal processing enables accurate high-throughput analysis without cell focusing mechanisms.•Electrical fingerprints discriminate between viable cells, necrotic cells and apoptotic bodies/cell debris.
Tumor-associated myeloid cells regulate tumor growth and metastasis, and their accumulation is a negative prognostic factor for breast cancer. Here we find calcium/calmodulin-dependent kinase kinase ...(CaMKK2) to be highly expressed within intratumoral myeloid cells in mouse models of breast cancer, and demonstrate that its inhibition within myeloid cells suppresses tumor growth by increasing intratumoral accumulation of effector CD8
T cells and immune-stimulatory myeloid subsets. Tumor-associated macrophages (TAMs) isolated from Camkk2
mice expressed higher levels of chemokines involved in the recruitment of effector T cells compared to WT. Similarly, in vitro generated Camkk2
macrophages recruit more T cells, and have a reduced capability to suppress T cell proliferation, compared to WT. Treatment with CaMKK2 inhibitors blocks tumor growth in a CD8
T cell-dependent manner, and facilitates a favorable reprogramming of the immune cell microenvironment. These data, credential CaMKK2 as a myeloid-selective checkpoint, the inhibition of which may have utility in the immunotherapy of breast cancer.
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•Dramatic self-heating until self-combustion tannery sludge.•Pyrophoric iron sulfides formation in tannery sludge drying under suboxic atmosphere.•In the sludge, the chemistry of iron ...sulfides in marine systems is reproduced.•Lab-scale preparation of reactive dried sludge.•Sludge characterization by physical and chemical analytical techniques.
Similarly to many powders of solids, dried sludge originated from tannery wastewater may result in a self-heating process, under given circumstances. In most cases, it causes a moderate heating (reaching 70–90°C), but larger, off-design residence times in the drier, in a suboxic atmosphere, extremely reactive solids can be produced. Tannery waste contains several chemicals that mostly end up in the wastewater treatment sludge. Unexpected and uncontrolled self heating could lead to a combustion and even to environmental problems. Elaborating on previous studies, with the addition of several analytical determinations, before and after the self-heating, we attempted to formulate a mechanism for the onset of heating. We demonstrated that the system Fe/S/O has been involved in the process. We proved that the formation of small quantities of pyrophoric iron sulfides is the key. They are converted to sulfated by reaction with water and oxygen with exothermic processes. The pyrite/pyrrhotite production depends on the sludge drying process. The oxidation of sulfides to oxides and sulfates through exothermic steps, reasonably catalyzed by metals in the sludge, occurs preferentially in a moist environment. The mechanism has been proved by reproducing in the laboratory prolonged heating under anoxic/suboxic atmosphere.
Synergy in flame retardancy of polyurethane foams between phosphorus-based flame retardant (aluminium phosphinate) and layered silicates has been investigated. We used pristine montmorillonite as ...well as ammonium modified clay (commercially available) and diphosphonium modified clay, which were synthesised by the intercalation of the quaternary diphosphonium salt according to a procedure reported here. The morphology of the foams was characterised through X-ray diffraction (XRD), while thermal properties were characterised by oxygen index test, cone calorimeter and thermogravimetric analysis (TGA). The morphological characterisation showed that pristine and diphosphonium modified clays are almost slightly intercalated, while ammonium modified one is very well dispersed. The results of thermal characterisation showed that in the presence of phosphinate enhancements of oxygen index, fire behaviour, measured by cone calorimeter, and thermal stability have been achieved. Phosphinate is therefore an efficient flame retardant for polyurethane foams and its flame retardancy action takes place in both condensed and gas phases. Pristine and ammonium modified layered silicate bring some enhancements of thermal stability while having no important effect in decreasing peak heat release rate (PHRR) and total heat evolved (THE) when used in conjunction with phosphinate; their main advantage is related to the enhancement of compactness of the char layer formed. Diphosphonium clay is instead effective in further improving the fire behaviour of the foams because of the flame retardancy action of phosphonium: both PHRR and THE were decreased. The analysis of cone calorimeter data showed that clays act through physical effect constituting a barrier at the surface which is effective in preventing or slowing the diffusion of volatiles and oxygen, while phosphinate and phosphonium are more effective owing to their combined action in both condensed and gas phases.
The paper reports the results of a project aiming to obtain multifunctional binary and ternary polymer nanocomposites with enhanced mechanical and anti-microbial properties. To this end a DGEBA-based ...epoxy resin is loaded using montmorillonite clays and later used as matrix for glass fibre reinforced laminates. Both binary and ternary nanomodified specimens are manufactured and subjected to mechanical testing. An accurate analysis of the effect of nanomodification on the biological activity is carried out as well.
•Results from nanocomposites with enhanced mechanical and anti-microbial properties are presented.•Epoxy is loaded with nanoclays and used as matrix for glass fibre reinforced laminates.•Binary and ternary nanomodified specimens are manufactured and tested.•The effect of nanomodification on the biological activity is studied.
•Fully endoscopic clipping of internal carotid and middle cerebral artery aneurysms may be safe and feasible.•Fully endoscopic approaches may allow neurosurgeons to take the most advantage of ...minimally invasive approaches, such as the transpalpebral approach.•In fully endoscopic approaches, it may be feasible to attain both proximal and distal vascular control of intracranial aneurysms.•Fully endoscopic approaches may pave the way for innovation in vascular neurosurgery.
► Handbook of who, how much and where for the geothermal electricity in the world. ► The most recent update for geothermal electricity history for each country. ► Ranking of the top countries, ...geothermal fields, operators and manufacturers. ► Forecasting for short and long term, per country, region and world and CO
2 saving. ► Classification of power plant categories, in number of units, MW and GWh.
We have analyzed the major activities carried out for geothermal electricity generation since WGC2005. New data have been taken from WGC2010 country update reports, private communications from IGA members and affiliated organizations. Other updates have been collected from websites of private and public organizations involved in geothermal development. Plants commissioned in 2010 (after WGC2010) have been included in the installed capacity, even though their produced energy has not been accounted for. An increase of about 2
GW (herein we use MW and GW for the electrical capacity and MW
th and GW
th for thermal capacity) in the five year term 2005–2010 has been achieved (about 22%), following the rough linear trend of approximately 400
MW/year, with an evident increase of the average value of about 200
MW/year in the 2000–2005 period (
Bertani, 2005a,b, 2006, 2007). The most significant data to be highlighted from this paper are:
•
a total of 24 countries now generate electricity from geothermal resources;
•
the total installed capacity worldwide is 10,898
MW, corresponding to about 67,246
GWh of electricity (early 2010 data);
•
Germany, Papua – New Guinea, Australia, Turkey, Iceland, Portugal, New Zealand, Guatemala, Kenya, and Indonesia have increased the capacity of their power plant installations by more than 50% with respect to the year 2005;
•
the top five countries for their electricity production are USA, Philippines, Indonesia, Mexico and Italy;
•
five countries realized an increase above 100
MW with respect to 2005: USA, Indonesia, Iceland, New Zealand and Kenya.
The prospective for growth during 2010–2015 are good, with a strong possibility of realizing a big increase in the installed capacity up to 19
GW, if all the currently identified projects would be realized all around the world.
A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, ...implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods.
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