bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatty acid starvation activates RelA by depleting lysine precursor pyruvate
Authors: Sinha Anurag Kumar , Winther Kristoffer Skovbo , Roghanian Mohammad , Gerdes Kenn 
Published: August 2019

SummaryBacteria undergoing nutrient starvation induce the ubiquitous stringent response, resulting in gross physiological changes that reprograms cell metabolism from fast to slow growth. The stringent response is mediated by the secondary messengers pppGpp and ppGpp collectively referred to as (p)ppGpp or ‘alarmone’. In Escherichia coli, two paralogs, RelA and SpoT, synthesize (p)ppGpp. RelA is activated by amino acid starvation, whereas SpoT, which can also degrade (p)ppGpp, responds to fatty acid (FA), carbon and phosphate starvation. Here, we discover that FA starvation leads to rapid activation of RelA and reveal the underlying mechanism. We show that FA starvation leads to depletion of lysine that, in turn, leads to the accumulation of uncharged tRNALys and activation of RelA. SpoT was also activated by FA starvation but to a lower level and with a delayed kinetics. Next, we discovered that pyruvate, a precursor of lysine, is depleted by FA starvation. We also propose a mechanism that explains how FA starvation leads to pyruvate depletion. Together our results raise the possibility that RelA may be a major player under many starvation conditions previously thought to depend principally on SpoT. Interestingly, FA starvation provoked a ~100‐fold increase in relA dependent ampicillin tolerance.
Clinical and neuroimaging profiles to identify C9orf72‐FTD patients and serum Neurofilament to monitor the progression and the severity of the disease
Authors: Lucidi Giulia , Berti Valentina , Piaceri Irene , Ginestroni Andrea , Lombardi Gemma , Ferrari Camilla , Polito Cristina , Bessi Valentina , Pupi Alberto , Nacmias Benedetta , Sorbi Sandro , Bagnoli Silvia 
Published: August 2019

AbstractBackgroundThe C9orf72 pathogenetic GGGGCC hexanucleotide repeat expansion is one of the most common causes of Frontotemporal Dementia (FTD), and early identification of this mutation is crucial for clinical and prognostic outcome. Although promising preclinical studies tried to evaluate the efficacy of biomarkers to identify C9orf72 expansion carriers, they have not been adequately assessed in humans.AimTo identify clinical, neuroimaging, and biological features that could be used to identify FTD subjects eligible to genetic testing.MethodsThis is a retrospective, case‐control study of clinical, neuropsycological, biological, and neuroimaging data of C9orf72 expansion carriers compared with non‐mutated FTD patients. Neurofilament light chain was evaluated by Quanterix Simoa essay.ResultsThe study revealed a set of peculiar characteristics in patients with C9orf72 expansion, compared with not expanded, as: lower age at onset, higher number of familial form and affected relatives, higher FTD‐MND symptoms, frequent behavioral and motor disorders at onset, higher incidence of dysphagia, lower mnesic deficits and higher rate of “Average” and “Rapid” progression of the disease. Neuroimaging data reveled that C9orf72 subgroup patients showed a higher hypometabolism of the frontal lobes involving both cortical and subcortical regions. Moreover, in symptomatic C9orf72 patients, NfL concentration was strongly elevated compared with presymptomatic carriers, increasing after 1 year of follow‐up.ConclusionThe metabolic signature combined with the clinical features could be a helpful tool to direct the genetic counseling. We confirmed that serum NfL evaluation could be a valid biomarker to monitor the disease severity and progression.
Environmental heterogeneity generates intrapopulation variation in life‐history traits in an annual plant
Authors: Friedman Jannice , Middleton Taylor E. , Rubin Matthew J. 
Published: August 2019

Summary

Environmental variation affects a plant's life cycle by influencing the timing of germination and flowering, and the duration of the growing season. Yet we know little information about how environmental heterogeneity generates variation in germination schedules and the consequences for growth and fecundity through genetic and plastic responses.

We use an annual population of Mimulus guttatus in which, in nature, seeds germinate in both fall and spring. We investigate whether there is a genetic basis to the timing of germination, the effect of germination timing on fecundity, and if growth and flowering respond plastically to compensate for different season lengths.

Using sibling families grown in simulated seasonal conditions, we find that families do not differ in their propensity to germinate between seasons. However, the germination season affects subsequent growth and flowering time, with significant genotype‐by‐environment interactions (G × E). Most G × E is due to unequal variance between seasons, because the spring cohort harbours little genetic variance. Despite their different season lengths, the cohorts do not differ in flower number (fecundity).

Heterogeneous environments with unpredictable risks may maintain promiscuous germination, which then affects flowering time. Therefore, if selection at particular life stages changes with climate change, there may be consequences for the entire life cycle.
Increased adaxial stomatal density is associated with greater mesophyll surface area exposed to intercellular air spaces and mesophyll conductance in diverse C4 grasses
Authors: Pathare Varsha S. , Koteyeva Nuria , Cousins Asaph B. 
Published: August 2019

Summary

Mesophyll conductance (gm) is the diffusion of CO2 from intercellular air spaces (IAS) to the first site of carboxylation in the mesophyll cells. In C3 species, gm is influenced by diverse leaf structural and anatomical traits; however, little is known about traits affecting gm in C4 species.

To address this knowledge gap, we used online oxygen isotope discrimination measurements to estimate gm and microscopy techniques to measure leaf structural and anatomical traits potentially related to gm in 18 C4 grasses.

In this study, gm scaled positively with photosynthesis and intrinsic water‐use efficiency (TEi), but not with stomatal conductance. Also, gm was not determined by a single trait but was positively correlated with adaxial stomatal densities (SDada), stomatal ratio (SR), mesophyll surface area exposed to IAS (Smes) and leaf thickness. However, gm was not related to abaxial stomatal densities (SDaba) and mesophyll cell wall thickness (TCW).

Our study suggests that greater SDada and SR increased gm by increasing Smes and creating additional parallel pathways for CO2 diffusion inside mesophyll cells. Thus, SDada, SR and Smes are important determinants of C4‐gm and could be the target traits selected or modified for achieving greater gm and TEi in C4 species.
Impacts of ocean warming on kelp forest ecosystems
Authors: Smale Dan A. 
Published: August 2019

SummaryKelp forests represent some of the most diverse and productive habitats on Earth, and provide a range of ecosystem goods and services on which human populations depend. As the distribution and ecophysiology of kelp species is strongly influenced by temperature, recent warming trends in many regions have been linked with concurrent changes in kelp populations, communities and ecosystems. Over the past decade, the number of reports of ocean warming impacts on kelp forests has risen sharply. Here, I synthesise recent studies to highlight general patterns and trends. While kelp responses to climate change vary greatly between ocean basins, regions and species, there is compelling evidence to show that ocean warming poses an unequivocal threat to the persistence and integrity of kelp forest ecosystems in coming decades.
Functional ecology of congeneric variation in the leaf economics spectrum
Authors: Ji Wenli , LaZerte Stefanie E. , Waterway Marcia J. , Lechowicz Martin J. 
Published: August 2019

Summary

Variation in resource availability can lead to phenotypic plasticity in the traits comprising the world‐wide leaf economics spectrum (LES), potentially impairing plant function and complicating the use of tabulated values for LES traits in ecological studies.

We compared 14 Carex (Cyperaceae) species in a factorial experiment (unshaded/shaded × sufficient/insufficient P) to analyze how changes in the network of allometric scaling relationships among LES traits influenced growth under favorable and resource‐limited conditions.

Changes in leaf mass per area (LMA) shifted the scaling relationships among LES traits expressed per unit area vs mass in ways that helped to sustain growth under resource limitation. Increases in area‐normalized photosynthetic capacity and foliar nitrogen (N) were correlated with increased growth, offsetting losses associated with mass‐normalized dark respiration and foliar N. These shifts increased the contributions to growth associated with photosynthetic N‐use efficiency and the N : P ratio.

Plasticity in LMA is at the hub of the functional role of the LES as an integrated and resilient complex system that balances the relationships among area‐ and mass‐based aspects of gas exchange and foliar nutrient traits to sustain at least some degree of plant growth under differing availabilities of above‐ and below‐ground resources.
Dual Credit Markets and Household Usage to Finance: Evidence from a Representative Chinese Household Survey
Authors: Cull Robert , Gan Li , Gao Nan , Xu Lixin Colin 
Published: August 2019

AbstractUsing a new and representative data set of Chinese household finance, we document household usage and costs of finance, along with their correlates. As in many developing countries, informal credit is a crucial element of household finance, and interest‐free informal loans based on reciprocal personal relationships are highly prevalent in our sample. Not surprisingly, wealth tends to be associated with greater usage of both formal and informal finance. Political connections, extensive social networks and certain household demographic characteristics (such as size) are all positively associated with formal or informal credit usage (or both). Overall, our findings show signs that a dual credit market is emerging in China, with the poor, politically unconnected, and those with larger family sizes still heavily reliant on informal finance, most of which are interest‐free, while younger, wealthier households with better political connections and financial knowledge are increasingly using formal finance.
Income Tax Progressivity: Trends and Implications
Authors: Gerber Claudia , Klemm Alexander , Liu Li , Mylonas Victor 
Published: August 2019

AbstractThis paper discusses how the structure of the tax system affects its progressivity. It suggests a measure of progressive capacity of tax systems, based on the Kakwani index, but independent of pretax income distributions. Using this and other progressivity measures, the paper (i) documents a decline in progressivity over the last decades and (ii) examines the relationship between progressivity and economic growth. On this relationship, regressions do not reveal a significant impact, suggesting that efficiency costs may be small – at least for degrees of progressivity observed in the sample. Finally, the paper finds that increasing tax progressivity reduces pretax inequality.
Improved accuracy and confidence with multiple‐lead recordings from a single‐lead mobile electrocardiographic device
Authors: Frisch Daniel R. , Weiss Max , Dikdan Sean J. , Keith Scott W. , Sarkar Kumar 
Published: August 2019

AbstractBackgroundMobile electrocardiograms (mECGs) utilizing smartphone applications are an emerging technology. Typically, a Lead I rhythm strip is recorded. However, interpretation can be difficult in patients with sinus rhythm and low amplitude P‐waves (SR‐LAP) or atrial flutter (AFL). We hypothesized that patients could independently obtain multi‐lead tracings using a commercial mECG device, and that cardiologists who interpreted the multi‐lead tracings would make more accurate diagnoses and have more confidence in their interpretation compared to a single lead only.MethodsThirty sets of recordings were obtained from 10 patients with either SR‐LAP or AFL that was not apparent on Lead I on a standard ECG. Patients recorded Lead I, Lead II, and Lead V1 tracings using AliveCor's KardiaMobile mECG device. Twenty‐nine cardiologists reviewed each patient's Lead I tracing, multi‐lead tracings (Leads I, II, V1), and 12‐lead ECG. Accuracy was noted and each cardiologist rated their level of confidence in their interpretation.ResultsAll patients were able to record their own single and multi‐lead tracings. Single lead, multi‐lead, and the 12‐lead ECG yielded 36.4%, 84.3%, and 97.7% agreement with the established diagnosis, respectively (P < .01 for each comparison). Overall mean confidence scores (out of a score of 5) were 2.95, 3.50, and 4.47 for single lead, multi‐lead, and the 12‐lead ECG, respectively (P < .01 for each comparison).ConclusionsPatients were able to record their own multi‐lead mECG tracings. Compared to a single lead recording, multi‐lead mECGs significantly improved cardiologists’ diagnostic accuracy and confidence in their interpretation approaching that of a standard 12‐lead ECG.
Examination of retinal vascular trajectory in schizophrenia and bipolar disorder
Authors: Appaji Abhishek , Nagendra Bhargavi , Chako Dona M. , Padmanabha Ananth , Jacob Arpitha , Hiremath Chaitra V. , Varambally Shivarama , Kesavan Muralidharan , Venkatasubramanian Ganesan , Rao Shyam V. , Webers Carroll A. B. , Berendschot Tos T. J. M. , Rao Naren P. 
Published: August 2019

AimEvidence suggests microvascular dysfunction (wider retinal venules and narrower arterioles) in schizophrenia (SCZ) and bipolar disorder (BD). The vascular development is synchronous with neuronal development in the retina and brain. The retinal vessel trajectory is related to retinal nerve fiber layer thinning and cerebrovascular abnormalities in SCZ and BD and has not yet been examined. Hence, in this study we examined the retinal vascular trajectory in SCZ and BD in comparison with healthy volunteers (HV).MethodsRetinal images were acquired from 100 HV, SCZ patients, and BD patients, respectively, with a non‐mydriatic fundus camera. Images were quantified to obtain the retinal arterial and venous trajectories using a validated, semiautomated algorithm. Analysis of covariance and regression analyses were conducted to examine group differences. A supervised machine‐learning ensemble of bagged‐trees method was used for automated classification of trajectory values.ResultsThere was a significant difference among groups in both the retinal venous trajectory (HV: 0.17 ± 0.08; SCZ: 0.25 ± 0.17; BD: 0.27 ± 0.20; P < 0.001) and the arterial trajectory (HV: 0.34 ± 0.15; SCZ: 0.29 ± 0.10; BD: 0.29 ± 0.11; P = 0.003) even after adjusting for age and sex (P < 0.001). On post‐hoc analysis, the SCZ and BD groups differed from the HV on retinal venous and arterial trajectories, but there was no difference between SCZ and BD patients. The machine learning showed an accuracy of 86% and 73% for classifying HV versus SCZ and BD, respectively.ConclusionSmaller trajectories of retinal arteries indicate wider and flatter curves in SCZ and BD. Considering the relation between retinal/cerebral vasculatures and retinal nerve fiber layer thinness, the retinal vascular trajectory is a potential marker for SCZ and BD. As a relatively affordable investigation, retinal fundus photography should be further explored in SCZ and BD as a potential screening measure.
Fast and Efficient Method to Obtain Tagitinin F by Photocyclization of Tagitinin C
Authors: Fernandes Victor Hugo Catricala , Viera Natalie de Barros , Zanini Luiza Beatriz Lima , Silva Aline de Fátima , Salem Paula Pio de Oliveira , Soares Marisi Gomes , Nicácio Karen de Jesus , de Paula Ana Claudia Chagas , Virtuoso Luciano Sindra , Oliveira Tiago Branquinho , Silva Eliane de Oliveira , Dias Danielle Ferreira , Chagas‐Paula Daniela Aparecida 
Published: August 2019

AbstractThere is some evidence in the literature of the photocyclization reaction of Tagitinin C (1) to Tagitinin F (2). Compound 2 has high pharmacological potential, but it is not easy to obtain, while compound 1 is easily obtained from a widespread plant, Tithonia diversifolia. Among different reaction conditions monitored, one was found that allowed the cyclization of 1 into 2 in <15 min in a photo‐dependent reaction. Scaling‐up the photocyclization of the pure compound 1 into 2 demonstrated 100% yield, and the isolation of 2 from a UV‐irradiated extract was eight‐fold higher than the quantity isolated from the non‐UV‐irradiated extract. We were also able to better understand the process of photoconversion and determine methods to isolate and quantify these compounds, which are known for their important antitumoral activities among other important pharmacological properties.
Evaluating success of various restorative interventions through drone‐ and field‐collected data, using six putative framework species in Argentinian Patagonia
Authors: Pérez Daniel R. , Pilustrelli Claudio , Farinaccio Fernando M. , Sabino Guillermo , Aronson James 
Published: August 2019

Field data and unmanned aerial vehicles, also known as drones, were used to analyze a long‐term experiment in a severely degraded area of the “Monte,” one of the most arid and degraded biomes in Argentina. Field methods and drone orthoimages obtained from flights of a quadcopter at 20 and 40 m were used to compare plantation plots versus natural recovery on scarified sites, and the field performance of six putative framework species under four different treatments was evaluated. After 5 years of recovery in soils with almost no organic matter and mean annual rainfall averaging 145 mm, plantation plots had high survival rates (>65%) for all species as determined through both field survey and drone imagery. Three species were planted with a greater number of seedlings due to their availability in nurseries. For these species experimental treatments were studied statistically. Independently of treatment applied (control; 1/2 L hydrogel; 1 L hydrogel; 1 L of hydrogel + 1/2 kg of organic compost), highest survival rates were found for P. flexuosa var. depressa (88% ± 14.8) and A. lampa (84% ± 14.8). Drone images and field data both showed that these two putative framework species had the highest plant cover. In sharp contrast, mechanical scarification without planting or other treatments induced very low recovery (<2%). We demonstrate that drone imagery provides a new and very valuable tool for evaluating and monitoring restorative interventions in drylands.
Validation and method comparison of the use of densitometry to quantify monoclonal proteins in canine sera
Authors: Harris Adam Dugger , Rout Emily , Avery Anne , Bolte Denise , Belling‐Kelly Erica , Moore A Russell 
Published: August 2019

AbstractBackgroundDensitometric quantitation using serum protein electrophoresis (SPE) is used to monitor monoclonal proteins (M‐proteins) in human patients but has not been validated in the dog. Serum globulin concentrations, species‐specific radial immunodiffusion (RID), and ELISAs are currently used in veterinary medicine.ObjectiveWe aimed to compare four methods that quantify M‐proteins using densitometry and biuret protein (dM‐protein) measurements. We also validated the best performing method and compared it with the RID and ELISA methods for measuring canine serum M‐protein.MethodSerum from six normal dogs and 83 serum samples from 46 dogs with confirmed monoclonal gammopathies were used. A spike and recovery experiment with purified monoclonal IgG and IgM, inter‐run and intra‐run variability, linearity under dilution, and lower limit of detection were performed. Results of commercial canine RID and ELISA kits for total class‐specific immunoglobulin were compared with dM‐proteins.ResultsThe corrected perpendicular drop gating method had <20% error for IgG/γ‐globulin and IgM/β‐globulin M‐protein quantifications. Linearity (r > .99), intra‐run CV (1.1%‐2.3%), and inter‐run CVs (2.0%‐3.5%) were acceptable. Correlation between the RID and densitometry results ranged from r = .25 to r = .88, depending on the class. The RID result was greater than that of the biuret total protein in 26/63 (41%) IgA cases. A panel of IgG, IgA, and IgM RIDs failed to correctly identify an IgM paraproteinemia in 6/6 (100%) cases. Densitometry was not comparable with any other tested method.ConclusionDensitometric quantitation is a valid technique for measuring M‐proteins in the β‐ and γ‐globulin regions. Immunotyping via RID using the tested kit does not appear to detect IgM. Densitometry is recommended for measuring M‐proteins in canine patients.
Mechanisms of soil moisture availability in vadose zone of a sand dune system: Linking soil physical properties and rainfall patterns
Authors: Zhou Hong , Zhao Wen-zhi 
Published: August 2019

AbstractSand dune systems in the arid region of north‐western China are maintained by sand‐stabilizing vegetation, which provides critical ecosystem services. Limited knowledge of soil moisture recharge in these systems hinders sand stabilization efforts. To increase the understanding of soil moisture response to rainfall, we analysed soil water transport in the desert vadose zone of sand dunes and dune slacks following four natural rainfall events during the growing season of 2017. Rainfall was dominated by small rain events (<5.0 mm), accounting for 58% of total rainfall events. Soil moisture at 5–25 cm depth in dune slacks was significantly higher and more variable to 60 cm depth than in sand dunes. Soil moisture at 5 cm depth was replenished with rainfall amounts of <5 mm in dune slacks, but not in sand dunes. When rainfall amount reached 20 mm, soil moisture in dune slack and in sand dune increased, but was much higher in dune slack than in sand dune at depth of 5 cm; after the rain, soil moisture remained at a relatively high level in dune slack but not in sand dune. This was possible because dune slacks had higher silt contents and root biomass, which played a key role in improving soil water holding capacity or accelerating rainfall infiltration at 0–25 cm depth. Overall, the rainfall‐driven hydrological regime coupled with soil physical factors regulated spatial and temporal variability of soil moisture in a sand dune system.
Assessing rainwater harvesting systems and reliability analysis of storage tanks: a monitoring study and system simulation
Authors: Molaei Oweis , Kouchakzadeh Mahdi , Haghighi Fashi Fereshte 
Published: August 2019

AbstractThis study applied a simulation model to evaluate the reliability of rainwater harvesting systems (RWHs) and the potential for rainwater storage was investigated in three different buildings. The results indicated that the tank stores 97.7% of the run‐off from the gym roof. Modelling the volume of the tank connected to the gym roof showed that 100% reliability can not be achieved for a roof with a relatively small area. The reliability for a tank larger than 2600 L was independent of the size of the tank. Maximum reliability of the RWHs was 70% of the total days of the year for a tank volume of 10 000 L, 300 m2 roof area and daily demand of 300 L (60% demand). Minimum reliability was 3% of the total days of the year for a tank volume of 1000 L, 100 m2 roof area and a daily demand of 1000 L (80% demand).