We present a high-resolution (∼0 12, ∼16 au, mean sensitivity of 50 Jy beam−1 at 225 GHz) snapshot survey of 32 protoplanetary disks around young stars with spectral type earlier than M3 in the ...Taurus star-forming region using the Atacama Large Millimeter Array. This sample includes most mid-infrared excess members that were not previously imaged at high spatial resolution, excluding close binaries and objects with high extinction, thereby providing a more representative look at disk properties at 1-2 Myr. Our 1.3 mm continuum maps reveal 12 disks with prominent dust gaps and rings, 2 of which are around primary stars in wide binaries, and 20 disks with no resolved features at the observed resolution (hereafter smooth disks), 8 of which are around the primary star in wide binaries. The smooth disks were classified based on their lack of resolved substructures, but their most prominent property is that they are all compact with small effective emission radii (Reff,95% 50 au). In contrast, all disks with Reff,95% of at least 55 au in our sample show detectable substructures. Nevertheless, their inner emission cores (inside the resolved gaps) have similar peak brightness, power-law profiles, and transition radii to the compact smooth disks, so the primary difference between these two categories is the lack of outer substructures in the latter. These compact disks may lose their outer disk through fast radial drift without dust trapping, or they might be born with small sizes. The compact dust disks, as well as the inner disk cores of extended ring disks, that look smooth at the current resolution will likely show small-scale or low-contrast substructures at higher resolution. The correlation between disk size and disk luminosity correlation demonstrates that some of the compact disks are optically thick at millimeter wavelengths.
Skeletal muscle is a highly plastic tissue that plays a central role in human health and disease. Aging is associated with a decrease in muscle mass and function (sarcopenia) that is associated with ...a loss of independence and reduced quality of life. Gut microbiota, the bacteria, archaea, viruses, and eukaryotic microbes residing in the gastrointestinal tract are emerging as a potential contributor to age-associated muscle decline. Specifically, advancing age is characterized by a dysbiosis of gut microbiota that is associated with increased intestinal permeability, facilitating the passage of endotoxin and other microbial products (e.g., indoxyl sulfate) into the circulation. Upon entering the circulation, LPS and other microbial factors promote inflammatory signaling and skeletal muscle changes that are hallmarks of the aging muscle phenotype. This review will summarize existing literature suggesting cross-talk between gut microbiota and skeletal muscle health, with emphasis on the significance of this axis for mediating changes in aging skeletal muscle size, composition, and function.
Rings are the most frequently revealed substructure in Atacama Large Millimeter/submillimeter Array (ALMA) dust observations of protoplanetary disks, but their origin is still hotly debated. In this ...paper, we identify dust substructures in 12 disks and measure their properties to investigate how they form. This subsample of disks is selected from a high-resolution (∼0 12) ALMA 1.33 mm survey of 32 disks in the Taurus star-forming region, which was designed to cover a wide range of brightness and to be unbiased to previously known substructures. While axisymmetric rings and gaps are common within our sample, spiral patterns and high-contrast azimuthal asymmetries are not detected. Fits of disk models to the visibilities lead to estimates of the location and shape of gaps and rings, the flux in each disk component, and the size of the disk. The dust substructures occur across a wide range of stellar mass and disk brightness. Disks with multiple rings tend to be more massive and more extended. The correlation between gap locations and widths, the intensity contrast between rings and gaps, and the separations of rings and gaps could all be explained if most gaps are opened by low-mass planets (super-Earths and Neptunes) in the condition of low disk turbulence ( = 10−4). The gap locations are not well correlated with the expected locations of CO and N2 ice lines, so condensation fronts are unlikely to be a universal mechanism to create gaps and rings, though they may play a role in some cases.
Hydrocarbons are worldwide-distributed pollutants that disturb various ecosystems. The aim of this study was to characterize the short-lapse dynamics of soil microbial communities in response to ...hydrocarbon pollution and different bioremediation treatments. Replicate diesel-spiked soil microcosms were inoculated with either a defined bacterial consortium or a hydrocarbonoclastic bacterial enrichment and incubated for 12 weeks. The microbial community dynamics was followed weekly in microcosms using Illumina 16S rRNA gene sequencing. Both the bacterial consortium and enrichment enhanced hydrocarbon degradation in diesel-polluted soils. A pronounced and rapid bloom of a native gammaproteobacterium was observed in all diesel-polluted soils. A unique operational taxonomic unit (OTU) related to the Alkanindiges genus represented ∼ 0.1% of the sequences in the original community but surprisingly reached >60% after 6 weeks. Despite this Alkanindiges-related bloom, inoculated strains were maintained in the community and may explain the differences in hydrocarbon degradation. This study shows the detailed dynamics of a soil bacterial bloom in response to hydrocarbon pollution, resembling microbial blooms observed in marine environments. Rare community members presumably act as a reservoir of ecological functions in high-diversity environments, such as soils. This rare-to-dominant bacterial shift illustrates the potential role of a rare biosphere facing drastic environmental disturbances. Additionally, it supports the concept of "conditionally rare taxa," in which rareness is a temporary state conditioned by environmental constraints.
We have determined the three-dimensional (3D) architecture of the
Caulobacter crescentus genome by combining genome-wide chromatin interaction detection, live-cell imaging, and computational ...modeling. Using chromosome conformation capture carbon copy (5C), we derive ∼13 kb resolution 3D models of the
Caulobacter genome. The resulting models illustrate that the genome is ellipsoidal with periodically arranged arms. The
parS sites, a pair of short contiguous sequence elements known to be involved in chromosome segregation, are positioned at one pole, where they anchor the chromosome to the cell and contribute to the formation of a compact chromatin conformation. Repositioning these elements resulted in rotations of the chromosome that changed the subcellular positions of most genes. Such rotations did not lead to large-scale changes in gene expression, indicating that genome folding does not strongly affect gene regulation. Collectively, our data suggest that genome folding is globally dictated by the
parS sites and chromosome segregation.
► Chromatin interaction mapping and modeling elucidate
Caulobacter genome structure ► The genome is ellipsoidal with periodically arranged arms ► The
parS region shapes whole genome structure and affects chromatin compaction ► The
parS region is the only genomic region stably attached to the cell envelope
Autism spectrum disorders (ASD) are complex neurobiological disorders that impair social interactions and communication and lead to restricted, repetitive, and stereotyped patterns of behavior, ...interests, and activities. The causes of these disorders remain poorly understood, but gut microbiota, the 10
bacteria in the human intestines, have been implicated because children with ASD often suffer gastrointestinal (GI) problems that correlate with ASD severity. Several previous studies have reported abnormal gut bacteria in children with ASD. The gut microbiome-ASD connection has been tested in a mouse model of ASD, where the microbiome was mechanistically linked to abnormal metabolites and behavior. Similarly, a study of children with ASD found that oral non-absorbable antibiotic treatment improved GI and ASD symptoms, albeit temporarily. Here, a small open-label clinical trial evaluated the impact of Microbiota Transfer Therapy (MTT) on gut microbiota composition and GI and ASD symptoms of 18 ASD-diagnosed children.
MTT involved a 2-week antibiotic treatment, a bowel cleanse, and then an extended fecal microbiota transplant (FMT) using a high initial dose followed by daily and lower maintenance doses for 7-8 weeks. The Gastrointestinal Symptom Rating Scale revealed an approximately 80% reduction of GI symptoms at the end of treatment, including significant improvements in symptoms of constipation, diarrhea, indigestion, and abdominal pain. Improvements persisted 8 weeks after treatment. Similarly, clinical assessments showed that behavioral ASD symptoms improved significantly and remained improved 8 weeks after treatment ended. Bacterial and phagedeep sequencing analyses revealed successful partial engraftment of donor microbiota and beneficial changes in the gut environment. Specifically, overall bacterial diversity and the abundance of Bifidobacterium, Prevotella, and Desulfovibrio among other taxa increased following MTT, and these changes persisted after treatment stopped (followed for 8 weeks).
This exploratory, extended-duration treatment protocol thus appears to be a promising approach to alter the gut microbiome and virome and improve GI and behavioral symptoms of ASD. Improvements in GI symptoms, ASD symptoms, and the microbiome all persisted for at least 8 weeks after treatment ended, suggesting a long-term impact.
This trial was registered on the ClinicalTrials.gov, with the registration number NCT02504554.
Failure of bone fracture healing occurs in 5% to 10% of all patients. Nonunion risk is associated with the severity of injury and with the surgical treatment technique, yet progression to nonunion is ...not fully explained by these risk factors.
To test a hypothesis that fracture characteristics and patient-related risk factors assessable by the clinician at patient presentation can indicate the probability of fracture nonunion.
An inception cohort study in a large payer database of patients with fracture in the United States was conducted using patient-level health claims for medical and drug expenses compiled for approximately 90.1 million patients in calendar year 2011. The final database collated demographic descriptors, treatment procedures as per Current Procedural Terminology codes; comorbidities as per International Classification of Diseases, Ninth Revision codes; and drug prescriptions as per National Drug Code Directory codes. Logistic regression was used to calculate odds ratios (ORs) for variables associated with nonunion. Data analysis was performed from January 1, 2011, to December 31, 2012.
Continuous enrollment in the database was required for 12 months after fracture to allow sufficient time to capture a nonunion diagnosis.
The final analysis of 309 330 fractures in 18 bones included 178 952 women (57.9%); mean (SD) age was 44.48 (13.68) years. The nonunion rate was 4.9%. Elevated nonunion risk was associated with severe fracture (eg, open fracture, multiple fractures), high body mass index, smoking, and alcoholism. Women experienced more fractures, but men were more prone to nonunion. The nonunion rate also varied with fracture location: scaphoid, tibia plus fibula, and femur were most likely to be nonunion. The ORs for nonunion fractures were significantly increased for risk factors, including number of fractures (OR, 2.65; 95% CI, 2.34-2.99), use of nonsteroidal anti-inflammatory drugs plus opioids (OR, 1.84; 95% CI, 1.73-1.95), operative treatment (OR, 1.78; 95% CI, 1.69-1.86), open fracture (OR, 1.66; 95% CI, 1.55-1.77), anticoagulant use (OR, 1.58; 95% CI, 1.51-1.66), osteoarthritis with rheumatoid arthritis (OR, 1.58; 95% CI, 1.38-1.82), anticonvulsant use with benzodiazepines (OR, 1.49; 95% CI, 1.36-1.62), opioid use (OR, 1.43; 95% CI, 1.34-1.52), diabetes (OR, 1.40; 95% CI, 1.21-1.61), high-energy injury (OR, 1.38; 95% CI, 1.27-1.49), anticonvulsant use (OR, 1.37; 95% CI, 1.31-1.43), osteoporosis (OR, 1.24; 95% CI, 1.14-1.34), male gender (OR, 1.21; 95% CI, 1.16-1.25), insulin use (OR, 1.21; 95% CI, 1.10-1.31), smoking (OR, 1.20; 95% CI, 1.14-1.26), benzodiazepine use (OR, 1.20; 95% CI, 1.10-1.31), obesity (OR, 1.19; 95% CI, 1.12-1.25), antibiotic use (OR, 1.17; 95% CI, 1.13-1.21), osteoporosis medication use (OR, 1.17; 95% CI, 1.08-1.26), vitamin D deficiency (OR, 1.14; 95% CI, 1.05-1.22), diuretic use (OR, 1.13; 95% CI, 1.07-1.18), and renal insufficiency (OR, 1.11; 95% CI, 1.04-1.17) (multivariate P < .001 for all).
The probability of fracture nonunion can be based on patient-specific risk factors at presentation. Risk of nonunion is a function of fracture severity, fracture location, disease comorbidity, and medication use.
The dense clusters within the Serpens Molecular Cloud are among the most active regions of nearby star formation. In this paper, we use Gaia DR2 parallaxes and proper motions to statistically measure ...∼1167 kinematic members of Serpens, few of which have been previously identified, to evaluate the star formation history of the complex. The optical members of Serpens are concentrated in three distinct groups located at 380-480 pc; the densest clusters are still highly obscured by optically thick dust and have few optical members. The total population of young stars and protostars in Serpens is at least 2000 stars, including past surveys that were most sensitive to protostars and disks, and may be much higher. Distances to dark clouds measured from deficits in star counts are consistent with the distances to the optical star clusters. The Serpens Molecular Cloud is seen in the foreground of the Aquila Rift, dark clouds located at 600-700 pc, and behind patchy extinction, here called the Serpens Cirrus, located at ∼250 pc. Based on the lack of a distributed population of older stars, the star formation rate throughout the Serpens Molecular Cloud increased by at least a factor of 20 within the past ∼5 Myr. The optically bright stars in Serpens Northeast are visible because their natal molecular cloud has been eroded, not because they were flung outwards from a central factory of star formation. The separation between subclusters of 20-100 pc and the absence of an older population together lead to speculation that an external forcing was needed to trigger the active star formation.
Starch as a source, starch as a sink MacNeill, Gregory J.; Mehrpouyan, Sahar; Minow, Mark A.A. ...
Journal of experimental botany,
07/2017, Letnik:
68, Številka:
16
Journal Article
Recenzirano
Odprti dostop
Starch commands a central role in the carbon budget of the majority of plants on earth, and its biological role changes during development and in response to the environment. Throughout the life of a ...plant, starch plays a dual role in carbon allocation, acting as both a source, releasing carbon reserves in leaves for growth and development, and as a sink, either as a dedicated starch store in its own right (in seeds and tubers), or as a temporary reserve of carbon contributing to sink strength, in organs such as flowers, fruits, and developing non-starchy seeds. The presence of starch in tissues and organs thus has a profound impact on the physiology of the growing plant as its synthesis and degradation governs the availability of free sugars, which in turn control various growth and developmental processes. This review attempts to summarize the large body of information currently available on starch metabolism and its relationship to wider aspects of carbon metabolism and plant nutrition. It highlights gaps in our knowledge and points to research areas that show promise for bioengineering and manipulation of starch metabolism in order to achieve more desirable phenotypes such as increased yield or plant biomass.
The regulation of body fat stores and blood glucose levels is critical for survival. This review highlights growing evidence that leptin action in the central nervous system plays a key role in both ...processes. Investigation into underlying mechanisms has begun to clarify the physiological role of leptin in the control of glucose metabolism and raises interesting new possibilities for the treatment of diabetes and related disorders.
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