Recent studies have indicated that biosurfactants play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. A combination of ...caprylic acid (0.01 %
v
/
v
) together with rhamnolipids (0.04 %
v
/
v
) was applied to biofilms of
Pseudomonas aeruginosa
ATCC 15442,
Staphylococcus aureus
ATCC 9144 and a mixed culture under BioFlux flowthrough conditions and caused disruption of the biofilms. The biofilms were also treated with a combination of rhamnolipids (0.04 %
v
/
v
) and sophorolipids (0.01 %). Control treatments with PBS 1× had no apparent effect on biofilm disruption. The Gram-positive bacterium (
S. aureus
ATCC 9144) was more sensitive than
P. aeruginosa
ATCC 15442 in terms of disruption and viability as shown by Live/Dead staining. Disruption of biofilms of
P. aeruginosa
ATCC 15442 was minimal. Oxygen consumption by biofilms, after different treatments with biosurfactants, confirms that sophorolipid on its own is unable to kill/inhibit cells of
P. aeruginosa
ATCC 15442, and even when used in combination with rhamnolipids, under static conditions, no decrease in the cell viability was observed. Cells in biofilms exposed to mono-rhamnolipids (0.04 %
v
/
v
) showed behaviour typical of exposure to bacteriostatic compounds, but when exposed to di-rhamnolipids (0.04 %
v
/
v
), they displayed a pattern characteristic of bactericidal compounds.
The world's population will reach 10.4 billion in 2067, with 81% residing in Africa or Asia. Arable land available for food production will decrease to 0.15 ha per person. Temperature will increase ...in tropical and temperate zones, especially in the Northern Hemisphere, and this will push growing seasons and dairy farming away from arid areas and into more northern latitudes. Dairy consumption will increase because it provides essential nutrients more efficiently than many other agricultural systems. Dairy farming will become modernized in developing countries and milk production per cow will increase, doubling in countries with advanced dairying systems. Profitability of dairy farms will be the key to their sustainability. Genetic improvements will include emphasis on the coding genome and associated noncoding epigenome of cattle, and on microbiomes of dairy cattle and farmsteads. Farm sizes will increase and there will be greater lateral integration of housing and management of dairy cattle of different ages and production stages. Integrated sensors, robotics, and automation will replace much of the manual labor on farms. Managing the epigenome and microbiome will become part of routine herd management. Innovations in dairy facilities will improve the health of cows and permit expression of natural behaviors. Herds will be viewed as superorganisms, and studies of herds as observational units will lead to improvements in productivity, health, and well-being of dairy cattle, and improve the agroecology and sustainability of dairy farms. Dairy farmers in 2067 will meet the world's needs for essential nutrients by adopting technologies and practices that provide improved cow health and longevity, profitable dairy farms, and sustainable agriculture.
Highlights • Subjects performed a simple reaction time (RT) task in response to an auditory cue. • Transcranial magnetic stimulation (TMS) was applied on control and startle trials. • TMS induced a ...cortical silent period and delayed both control and startle RTs. • For a cortically dependent speech RT task, startling stimulus also sped response. • Results indicate cortical involvement in response triggering by startling stimulus.
Aims
To establish the ability of the rhamnolipids biosurfactants from Pseudomonas aeruginosa, in the presence and absence of caprylic acid and ascorbic acid, to disrupt bacterial biofilms, compared ...with the anionic alkyl sulphate surfactant Sodium dodecyl sulphate (SDS).
Methods and Results
Pseudomonas aeruginosa ATCC 15442 biofilms were disrupted by rhamnolipids at concentrations between 0·5 and 0·4 g l−1 and with SDS at 0·8 g l−1. The combination of rhamnolipids 0·4 g l−1 and caprylic acid at 0·1 g l−1 showed a remarkable effect on biofilm disruption and cell killing. After 30 min of treatment most of the biofilm was disrupted and cell viability was significantly reduced. Neither caprylic acid nor ascorbic acid has any effect on biofilm disruption at 0·1 g l−1. SDS is an effective antimicrobial agent; however, in the presence of caprylic acid its effect was neutralized.
Conclusions
The results show that rhamnolipids at low concentration in the presence of caprylic acid are promising molecules for inhibition/disruption of biofilms formed by Ps. aeruginosa ATCC 15442.
Significance and Impact of the Study
The disruption of biofilms has major significance in many industrial and domestic cleaning applications and in medical situations.
Neutron powder diffraction was used to determine changes in the nuclear and magnetic structures of Bi1−x Nd x FeO3 polymorphs involved in the first-order displacive phase transitions from the ...high-temperature nonpolar phase to the low temperature polar (x ≤ 0.125) and antipolar (0.125 ≤ x ≤ 0.25) phases, respectively. The high-temperature phase (O 1), which crystallizes with a structure similar to the room-temperature form of NdFeO3, exhibits Pbnm symmetry and unit cell √2a c × √2a c × 2a c (where a c ≈ 4 Å is the lattice parameter of an ideal cubic perovskite), determined by a − a − c + octahedral tilting. The low-temperature polar structure (R) is similar to the β-phase of BiFeO3 and features rhombohedral symmetry determined by a − a − a − octahedral rotations and cation displacements. The recently discovered antipolar phase (O 2) resembles the antiferroelectric Pbam (√2a c × 2√2a c × 2a c) structure of PbZrO3 but with additional displacements that double the PbZrO3 unit cell along the c-axis to √2a c × 2√2a c × 4a c and yield Pbnm symmetry. The O 1 ↔ R and O 1 ↔ O 2 transitions are both accompanied by a large discontinuous expansion of the lattice volume in the low-temperature structures with a contrasting contraction of the FeO6 octahedral volume and an abrupt decrease in the magnitude of octahedral rotations. The O 1 ↔ O 2 transition, which occurs in the magnetic state, is accompanied by an abrupt ≈90° reorientation of the magnetic dipoles. This coupling between the nuclear and magnetic structures is manifested in a significant magnetization anomaly. Below 50 K, reverse rotation of magnetic dipoles back to the original orientations in the high-temperature O 1 structure is observed.
The discovery of planets around other stars is revolutionizing our notions of planet formation and is poised to do the same for planetary climate. Studying transiting planets is complementary to ...eventual studies of directly imaged planets: (1) we can readily measure the mass and radius of transiting planets, linking atmospheric properties to bulk composition and formation, (2) many transiting planets are strongly irradiated and exhibit novel atmospheric physics, and (3) the most common temperate terrestrial planets orbit close to red dwarf stars and are difficult to image directly. We have only been able to comprehensively characterize the atmospheres of a handful of transiting planets, because most orbit faint stars. The Transiting Exoplanet Survey Satellite (TESS) will discover transiting planets orbiting the brightest stars, enabling, in principle, an atmospheric survey of 102-103 bright hot Jupiters and warm sub-Neptunes. Uniform observations of such a statistically significant sample would provide leverage to understand-and learn from-the diversity of short-period planets, and would identify the minority of truly special planets worthy of more intensive follow-up. We argue that the best way to maximize the scientific returns of TESS is to adopt a triage approach. A space mission consisting of a ∼1 m telescope with an optical-NIR spectrograph could measure molecular absorption for nonterrestrial planets discovered by TESS, as well as eclipses and phase variations for the hottest jovians. Such a mission could observe up to 103 transits per year, thus enabling it to survey a large fraction of the bright (J < 11) hot-Jupiters and warm sub-Neptunes TESS is expected to find. The James Webb Space Telescope (JWST) could be used to perform detailed atmospheric characterization of the most interesting transiting targets (transit, eclipse, and-when possible-phase-resolved spectroscopy). TESS is also expected to discover a few temperate terrestrial planets transiting nearby M-Dwarfs. Characterizing these worlds will be time-intensive: JWST will need months to provide tantalizing constraints on the presence of an atmosphere, planetary rotational state, clouds, and greenhouse gases. Future flagship missions should be designed to provide better constraints on the habitability of M-Dwarf temperate terrestrial planets.
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•Self-assembly of ternary and 5-component surfactant mixtures studied.•In ternary mixtures, scattering data modelled as globular interacting micelles.•In ternary mixtures, variation ...in aggregation number implies micelle composition close to solution composition.•In 5-component mixture addition of rhamnolipid biosurfactants affects evolution in phase behaviour.•For rhamnolipid rich compositions transition from micelle to lamellar/micellar co-existence occurs.•Transition associated with synergistic packing effects.
The self-assembly of dilute aqueous solutions of a ternary surfactant mixture and rhamnolipid biosurfactant/surfactant mixtures has been studied by small angle neutron scattering. In the ternary surfactant mixture of octaethylene glycol monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene monododecyl sulfate, SLES, small globular interacting micelles are observed over the entire composition and concentration range studied. The modelling of the scattering data strongly supports the assumption that the micelle compositions are close to the solution compositions. In the 5-component rhamnolipid/surfactant mixture of the mono-rhamnose, R1, di-rhamnose, R2, rhamnolipids with C12E8/LAS/SLES, globular micelles are observed over much of the concentration and composition range studied. However, for solutions relatively rich in rhamnolipid and LAS, lamellar/micellar coexistence is observed. The transition from globular to more planar structures arises from a synergistic packing in the 5 component mixture. It is not observed in the individual components nor in the ternary C12E8/LAS/SLES mixture at these relatively low concentrations. The results provide an insight into how synergistic packing effects can occur in the solution self-assembly of complex multi-component surfactant mixtures, and give rise to an unexpected evolution in the phase behaviour.
The Soft X-ray focusing Telescope (SXT), India’s first X-ray telescope based on the principle of grazing incidence, was launched aboard the AstroSat and made operational on October 26, 2015. X-rays ...in the energy band of 0.3–8.0 keV are focussed on to a cooled charge coupled device thus providing medium resolution X-ray spectroscopy of cosmic X-ray sources of various types. It is the most sensitive X-ray instrument aboard the AstroSat. In its first year of operation, SXT has been used to observe objects ranging from active stars, compact binaries, supernova remnants, active galactic nuclei and clusters of galaxies in order to study its performance and quantify its characteriztics. Here, we present an overview of its design, mechanical hardware, electronics, data modes, observational constraints, pipeline processing and its in-orbit performance based on preliminary results from its characterization during the performance verification phase.
Milk and dairy products provide highly sustainable concentrations of essential amino acids and other required nutrients for humans; however, amount of milk currently produced per dairy cow globally ...is inadequate to meet future needs. Higher performing dairy cows and herds produce more milk with less environmental impact per kg than lower performing cows and herds. In 2018, 15.4% of the world’s dairy cows produced 45.4% of the world’s dairy cow milk, reflecting the global contribution of high-performing cows and herds. In high-performing herds, genomic evaluations are utilized for multiple trait selection, welfare is monitored by remote sensing, rations are formulated at micronutrient levels, health care is focused on prevention and reproduction is managed with precision. Higher performing herds require more inputs and generate more waste products per cow, thus innovations in environmental management on such farms are essential for lowering environmental impacts. Our focus is to provide perspectives on technologies and practices that contribute most to sustainable production of milk from high-performing dairy cows and herds.
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