| | Cell biology: Organelles under light control
Optogenetic techniques enable light-activated control of protein–protein interactions in the cell. This approach has now been used to alter membrane dynamics and induce cellular reorganization.
| Antibiotics: An irresistible newcomer
A screen of 10,000 bacterial strains, cultured in their normal soil, has uncovered an antibiotic with broad and potent activity. And because the compound targets lipid molecules, developing resistance is probably difficult.
| HIV: Seeking ultimate victory
HIV variants that have mutated to escape T-cell immune responses dominate the latent viral reservoir in most patients on antiretroviral therapy. This finding will need to guide therapeutic approaches targeting reactivated virus.
| A new antibiotic kills pathogens without detectable resistance
From a new species of β-proteobacteria, an antibiotic called teixobactin that does not generate resistance has been characterized; the antibiotic has two different lipid targets in different bacterial cell wall synthesis components, which may explain why resistance was not observed.
| Tel1ATM-mediated interference suppresses clustered meiotic double-strand-break formation
Meiotic recombination is initiated by a fairly uniform distribution of hundreds of DNA double-strand breaks catalysed by the Spo11 protein; here, Tel1 (orthologue of human ATM) is shown to be required for the localized inhibition that prevents double-strand breaks from forming close to one another.
| Evolution of the snake body form reveals homoplasy in amniote Hox gene function
Traditionally, the vertebral column of snakes was thought to have lost regionalization; Hox regionalization is now shown to be maintained in snakes, suggesting that gradational vertebral column regionalization is primitive to amniotes.
| Commensal–dendritic-cell interaction specifies a unique protective skin immune signature
Defined skin commensal bacteria elicit a dermal dendritic-cell-dependent, long-lasting, commensal-specific CD8+ T-cell response that promotes protection against pathogens while preserving tissue homeostasis.
| Broad CTL response is required to clear latent HIV-1 due to dominance of escape mutations
Despite receiving antiretroviral therapy, most patients with HIV still have latent reservoirs of the virus; here, these reservoirs are shown to be dominated by viruses with cytotoxic T lymphocyte escape mutations, with potential implications for the development of therapeutic vaccines.
| SLC38A9 is a component of the lysosomal amino acid sensing machinery that controls mTORC1
The mTORC1 protein kinase complex integrates nutrient and growth stimuli to modulate signalling pathways that regulate cellular metabolism and physiology, but the molecular nature of the amino acid sensing mechanism at the lysosome is unknown; here, an orphan member of the human solute carrier group of proteins, SLC38A9, is shown to be an integral component of the lysosomal machinery that can directly sense amino acids and activate mTORC1.
| A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster
The measurement of the rotational periods of 30 cool stars in the 2.5-billion-year-old cluster NGC 6819 allows the calibration of gyrochronology — the determination of a star's age on the basis of its rotation period — over a much broader age range than hitherto, meaning that it might be possible to determine the ages of many cool stars in the Galactic field with a precision of roughly 10 per cent.
| Optogenetic control of organelle transport and positioning
An optogenetic strategy allowing light-mediated recruitment of distinct cytoskeletal motor proteins to specific organelles is established; this technique enabled rapid and reversible activation or inhibition of the transport of organelles such as peroxisomes, recycling endosomes and mitochondria with high spatiotemporal accuracy, and the approach was also applied to primary neurons to demonstrate optical control of axonal growth by recycling endosome repositioning.
| Compositional engineering of perovskite materials for high-performance solar cells
Inorganic–organic lead halide perovskite could be efficient when used as the light-harvesting component of solar cells; here incorporation of methylammonium lead bromide into formamidinium lead iodide stabilizes the perovskite and improves the power conversion efficiency of the solar cell up to 17.9 per cent.
| A possible close supermassive black-hole binary in a quasar with optical periodicity
A search of a data set of light curves for 247,000 known, spectroscopically confirmed quasars with a temporal baseline of about 9 years reveals a strong, smooth periodic signal in the optical variability of quasar PG 1302−102 with a mean observed period of 1,884 ± 88 days, indicating a possible supermassive black-hole binary.
| | Three-dimensional head-direction coding in the bat brain
A study of freely moving bats provides new insights into how the brain encodes a three-dimensional neural compass; neurons were identified encoding the three Euler rotation angles of the head (azimuth, pitch, and roll) and recordings from these head-direction cells revealed a toroidal model of spatial orientation mapped out by cells tuned to two circular variables (azimuth × pitch).
Arseny Finkelstein, Dori Derdikman, Alon Rubin et al. | Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism
Mannan, a component of yeast cell walls, is shown to be a viable food source for Bacteroides thetaiotamicron, a dominant member of the gut microbiota, which catabolizes the mannan 'selfishly'—countering the general assumption that multiple members of the gut microbiota take a role in, and benefit from, polysaccharide catabolism.
Fiona Cuskin, Elisabeth C. Lowe, Max J. Temple et al. | Glutathione activates virulence gene expression of an intracellular pathogen
This study shows that glutathione, a ubiquitous antioxidant, is also a critical signalling molecule that allosterically activates the master virulence regulator in the intracellular pathogen Listeria monocytogenes.
Michelle L. Reniere, Aaron T. Whiteley, Keri L. Hamilton et al. | | Optically addressable nuclear spins in a solid with a six-hour coherence time
An essential ingredient of future worldwide quantum communication is the generation of long-lived entangled quantum states; a coherence time of six hours is now reported for optically addressable nuclear spins in europium-doped yttrium orthosilicate.
Manjin Zhong, Morgan P. Hedges, Rose L. Ahlefeldt et al. | The heat released during catalytic turnover enhances the diffusion of an enzyme
It has been traditionally assumed that the heat released during a single enzymatic catalytic event does not perturb the enzyme in any way; however, here single-molecule fluorescence correlation spectroscopy is used to show that, for enzymes that catalyse chemical reactions with large reaction enthalpies, the heat released at the protein's active site during catalysis transiently displaces the protein's centre-of-mass, essentially giving rise to a recoil effect that propels the enzyme.
Clement Riedel, Ronen Gabizon, Christian A. M. Wilson et al. | Copulation in antiarch placoderms and the origin of gnathostome internal fertilization
The discovery of claspers in fossils of antiarch placoderms, an ancient group of armoured fish, suggests that internal fertilization was the ancestral type of reproduction for all jawed vertebrates: this contrasts with the current understanding that external fertilization must be the ancestral state.
John A. Long, Elga Mark-Kurik, Zerina Johanson et al. | The temperature and chronology of heavy-element synthesis in low-mass stars
Spectrographically obtained zirconium, niobium and technetium abundances in a sample of low-mass stars of type S are used to determine that, in these stars, heavy elements are synthesized by the slow-neutron-capture process at a temperature of less than about 250 million kelvin, and that the process began one million to three million years ago.
P. Neyskens, S. Van Eck, A. Jorissen et al. | Calcium transient prevalence across the dendritic arbour predicts place field properties
In vivo evidence for the existence of regenerative dendritic events in place cell dendrites of awake, behaving mice suggests an active role for dendritic spikes in building the representation of space in the hippocampus.
Mark E. J. Sheffield, Daniel A. Dombeck | Precision microbiome reconstitution restores bile acid mediated resistance to Clostridium difficile
A fraction of the intestinal microbiota as precise as a single bacterial species confers infection resistance by synthesizing Clostridium difficile-inhibiting metabolites from host-derived bile salts.
Charlie G. Buffie, Vanni Bucci, Richard R. Stein et al. | Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland
Seismicity and ground deformation measurements show how a recent segmented dyke intrusion in the Bárðarbunga volcanic system in Iceland grew laterally for 45 kilometres over 14 days; dyke opening and seismicity were focused at the most distal segment, where lateral dyke growth with segment barrier breaking by pressure build-up occurred.
Freysteinn Sigmundsson, Andrew Hooper, Sigrún Hreinsdóttir et al. | T–B-cell entanglement and ICOSL-driven feed-forward regulation of germinal centre reaction
Interactions between T and B cells in the germinal centre are brief but involve extensive cell-surface contact in an entangled mode; ICOSL promotes T–B entanglement and B-cell acquisition of CD40L, which drives B cells to upregulate ICOSL, thus forming an intercellular feed-forward loop that is required for efficient positive selection and development of the bone marrow plasma cell compartment.
Dan Liu, Heping Xu, Changming Shih et al. | Blocking PGE2-induced tumour repopulation abrogates bladder cancer chemoresistance
Using human bladder cancer xenograft models, a new mechanism involving an active proliferative response of cancer stem cells to chemotherapy-induced damage is shown, driven by prostaglandin E2 (PGE2) release in a manner similar to PGE2-induced wound repair; pharmacological inhibition of the PGE2/COX2 axis by celecoxib attenuates chemoresistance, suggesting a possible adjunctive therapy for bladder carcinomas.
Antonina V. Kurtova, Jing Xiao, Qianxing Mo et al. | High-value alcohols and higher-oxidation-state compounds by catalytic Z-selective cross-metathesis
A ruthenium–disulfide catalyst is presented that is effective in generating compounds of medical and industrial utility (alcohols that contain a phenol, an aldehyde, or a carboxylic acid) by room-temperature, inexpensive, high-yielding cross-metathesis.
Ming Joo Koh, R. Kashif M. Khan, Sebastian Torker et al. | EFF-1-mediated regenerative axonal fusion requires components of the apoptotic pathway
Unlike the limited post-injury neuronal regeneration in humans, severed axons in C. elegans can regenerate through a cellular fusion mechanism; this study identifies the molecular basis for this process which includes phosphatidylserine recognition and a role for specific molecules that also act in apoptosis.
Brent Neumann, Sean Coakley, Rosina Giordano-Santini et al. | Allosteric activation of the RNF146 ubiquitin ligase by a poly(ADP-ribosyl)ation signal
Structural and biochemical approaches are used to show how RNF146 activity is allosterically regulated by the binding of poly(ADP-ribose) ligand, and how substrate specificity is achieved with protein poly(ADP-ribosyl)ation and ubiquitination occurring in the same protein complex.
Paul A. DaRosa, Zhizhi Wang, Xiaomo Jiang et al. | The geographical distribution of fossil fuels unused when limiting global warming to 2 °C
To limit global warming to a rise of 2 °C compared to pre-industrial levels, we cannot use all of our fossil fuel reserves; here an integrated assessment model shows that this temperature limit implies that we must leave unused a third of our oil reserves, half of our gas reserves and over 80 per cent of our coal reserves during the next 40 years, and indicates where these are geographically located.
Christophe McGlade, Paul Ekins | | | | |
No comments:
Post a Comment