Strong Response Research Articles

The context‐dependent benefits of organic farming on pollinator biodiversity: A meta‐analysis

Abstract Agricultural intensification is driving declines in pollinator diversity and the degradation of pollination services worldwide. Organic management, which prohibits the use of synthetic inputs, has considerable potential for combatting these declines by enhancing biodiversity in agricultural landscapes. However, the efficacy of organic farming for promoting pollinator diversity has recently been questioned. We conducted a meta‐analysis to determine the effect of organic management on pollinator species richness and abundance. We compiled 42 studies across four continents and calculated a Hedges' g effect size for each of 76 species richness and 57 abundance observations. We then estimated average effect sizes overall and across five moderators. Species richness and abundance of pollinating insects tended to be higher in organic farms than conventional ones, with average effect sizes of 0.68 and 0.74, respectively. Landscape context, crop type, pollinator group, sampling location, and sampling method were factors impacting the response of pollinator diversity/abundance to organic farming. We found benefits for pollinator diversity from organic farming in all landscape types, with the strongest response in simple compared with more complex landscapes. Pollinator diversity benefited the most in habitats within organic cereal systems and the least in organic pastures. Among pollinator groups, bumblebee diversity benefitted the most, while moths and hoverflies showed positive but non‐significant responses. Higher pollinator diversity/abundance was detected in organic farms at various sampling locations. Transect sampling showed the greatest diversity gains among sampling methods. Synthesis and applications. Our results affirm that organic farming has positive effects for pollinator species richness and abundance, but benefits are variable and not guaranteed. We recommend that future studies adopt a standard sampling protocol and cover a larger geographic range to understand the global potential of organic farming to promote pollinator biodiversity. Efforts to increase pollinator abundance and diversity through organic farming should focus on organic systems involving cereal phases, especially within simple landscapes, for the most positive outcomes. However, due to high variability in pollinator responses alongside the challenges to achieve economic profitability from organic farming, crafting organic farming systems to specific farm‐scale opportunities and needs may be necessary.

Fabrication and characterization of double-layer active intelligent film based on chitosan, polyvinyl alcohol, grape skin anthocyanin and selenium nanoparticle

This study involved the fabrication of double-layer intelligent films using chitosan (CS), polyvinyl alcohol (PVA), grape skin anthocyanin (GSA), gellan gum (GG) and selenium nanoparticles (SeNPs). The CS/PVA/GSA layer functioned as the internal indicator layer, and the GG/SeNPs layer acted as the external layer for antioxidant and antimicrobial purposes. SEM, FTIR, XRD, and TGA results confirmed the successful fabrication of double-layer films as well as the presence of hydrogen bonding interaction between the two layers. The tensile strength of double-layer films (8.06 MPa–9.61 MPa) fallen between that of single-layer CS/PVA/GSA film (12.51 MPa) and GG/SeNPs film (1.50 MPa–7.67 MPa). The double-layer films demonstrated good UV-blocking abilities, as well as outstanding antioxidant (ABTS scavenging rate can be up to ∼80 %) and antimicrobial properties. Compared with single-layer CS/PVA/GSA film, the double-layer film incorporated with 6.6 wt% SeNPs (CPG/GS2 film) possessed a more rapid and stronger response towards NH3/acetic acid as well as enhanced storage stability. Furthermore, the CPG/GS2 film can increase the shelf life of strawberries at 25 °C by 4 days, and its visible color change showed strong correlation with the weight loss rate (R2 = 0.99) and hardness (R2 = 0.98) of strawberries.

Soil Moisture Dominates the Land Surface Feedback in the Development of Compound Drought–Heat Extremes in Tropical South America

Abstract Observational evidence has demonstrated that heat extremes consistently coincide with droughts in tropical South America. However, the underlying causes and associated physical mechanisms remain relatively unexplored. In this study, we employ numerical experiments using Community Earth System Model, version 2 (CESM2), with prescribed oceanic forcing to assess how extreme soil temperature and moisture affect subsequent hydrometeorological conditions during the premonsoon season in tropical South America, a season when land can play an important role in regional climate. The results reveal a different diurnal pattern in the strength of the surface air temperature response, with a stronger response at night to soil temperature anomalies and a stronger response at noon to soil moisture anomalies. Elevated initial soil temperature or reduced initial soil moisture tends to yield warmer and drier hydrometeorological conditions and increase the occurrence of both drought and heat extremes, with stronger and longer-lasting responses to soil moisture anomalies (than soil temperature anomalies). The simulated responses to initial soil moisture anomalies alone closely resemble those in the experiment with combined soil temperature and moisture anomalies. These findings underscore the dominant role of soil moisture feedback in shaping compound drought–heat extremes, in regions where evaporation plays a significant role, highlighting its importance in the modeling and prediction of hydrometeorological extremes.

Comparison of Nocifensive Behavior in NaV1.7-, NaV1.8-, and NaV1.9-Channelrhodopsin-2 Mice by Selective Optogenetic Activation of Targeted Sodium Channel Subtype-Expressing Afferents.

Voltage-gated sodium channels, including NaV1.7, NaV1.8, and NaV1.9, play important roles in pain transmission and chronic pain development. However, the specific mechanisms of their action remain unclear, highlighting the need for invivo stimulation studies of these channels. Optogenetics, a novel technique for targeting the activation or inhibition of specific neural circuits using light, offers a promising solution. In our previous study, we used optogenetics to selectively excite NaV1.7-expressing neurons in the dorsal root ganglion of mice to induce nocifensive behavior. Here, we further characterize the impact of nocifensive behavior by activation of NaV1.7, NaV1.8, or NaV1.9-expressing neurons. Using CRISPR/Cas9-mediated homologous recombination, NaV1.7-iCre, NaV1.8-iCre, or NaV1.9-iCre mice expressing iCre recombinase under the control of the endogenous NaV1.7, NaV1.8, or NaV1.9 gene promoter were produced. These mice were then bred with channelrhodopsin-2 (ChR2) Cre-reporter Ai32 mice to obtain NaV1.7-ChR2, NaV1.8-ChR2, or NaV1.9-ChR2 mice. Blue light exposure triggered paw withdrawal in all mice, with the strongest response in NaV1.8-ChR2 mice. These light sensitivity differences observed across NaV1.x-ChR2 mice may be dependent on ChR2 expression or reflect the inherent disparities in their pain transmission roles. In conclusion, we have generated noninvasive pain models, with optically activated peripheral nociceptors. We believe that studies using optogenetics will further elucidate the role of sodium channel subtypes in pain transmission.

Flame aerosol deposition Y3Al5O12:Yb 3+ , Er 3+ nanoparticles on monolayer MoS2 for broadening near-infrared photoelectroresponse

Monolayer molybdenum disulfide (MoS2) is a two-dimensional material with a direct bandgap widely used in photoelectric detection. It exhibits excellent characteristics such as an ultra- high specific surface area, strong light interaction, and good carrier mobility. However, due to the bandgap limitation, monolayer MoS2 can only efficiently detect visible wavelengths less than 680 Combining lanthanide-doped upconversion nanoparticles with monolayer MoS2 to realize near- infrared (NIR) photodetection is a feasible strategy. Thus, Y3Al5O12:Yb 3+ , Er3+ up-conversion nanoparticles are deposited on the surface of a monolayer MoS2 by flame aerosol deposition (FAD), significantly extending their photoelectric response range to the near-infrared 980 nm. The Y3Al5O12:Yb 3+ , Er3+ nanoparticles synthesized by flame can achieve efficient up-conversion from near-infrared (~980 nm) to visible light (~450, ~550, ~650 nm). Therefore, the visible light can be subsequently absorbed by monolayer MoS2. The carefully designed Y3Al5O12:Yb 3+ , Er3+ /MoS2 photodetector shows strong responsivity and highly specific detectivity in the near-infrared spectrum. Under the bias voltage of 3 V and laser irradiation of 980 nm at 2.8 μW, the newly designed MoS2 device achieves a responsivity of 16.82 A/W and a specific detectivity of 1.47×10 12 Jones, as the traditional monolayer MoS2 usually responds to zero. This work can further expand the application of two-dimensional materials and their composites in near-infrared photoelectric detection

SU-8-meta-phenylenediamine-conjugated thin film for temperature sensing.

Polymers have distinctive optical properties and facile fabrication methods that have been well-established. Therefore, they have immense potential for nanophotonic devices. Here, we demonstrate the temperature-sensing potential of SU8-meta-phenylenediamine (SU8-mPD), produced by epoxy amination of the SU-8 polymer. Its properties were examined through a series of molecular structural techniques and optical methods. Thin layers have demonstrated optical emission and absorption in the visible range around 420 and 520 nm, respectively, alongside a strong thermal responsivity, characterized by the 18 ppm °C-1 expansion coefficient. A photonic chip, comprising a thin 5-10 μm SU8-mPD layer, encased between parallel silver and/or gold thin film mirrors, has been fabricated. When pumped by an external light source, this assembly generates a pronounced fluorescent signal that is superimposed with the Fabry-Pérot (FP) resonant response. The chip undergoes mechanical deformation in response to temperature changes, thereby shifting the FP resonance and encoding temperature information into the fluorescence output spectrum. The time response of the device was estimated to be below 1 s for heating and a few seconds for cooling, opening a new avenue for optical sensing using SU8-based polymers. Thermoresponsive resonant structures, encompassing strong tunable fluorescent properties, can further enrich the functionalities of nanophotonic polymer-based platforms. This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'.

Airway epithelial cell response to RSV is mostly impaired in goblet and multiciliated cells in asthma

BackgroundIn patients with asthma, respiratory syncytial virus (RSV) infections can cause disease exacerbation by infecting the epithelial layer of the airways, inducing subsequent immune response. The type I interferon antiviral...

The response of labour demand to different COVID-19 containment measures: evidence from online job postings in Austria

This paper analyses changes in the speed of labour demand for new hires in response to the lockdowns that were repeatedly put in place to contain the spread of the COVID-19 pandemic. It tests whether the uncertainty-reducing effect of similar lockdowns occurring in quick succession increased the responsiveness of the labour market, thereby allowing for more rapid adjustment, both at the beginning and at the end of subsequent lockdowns. It uses high-frequency online job-posting data and applies an event study approach to the beginning of three national lockdowns and the subsequent reopening in Austria between 2020 and 2022. In view of the importance of progress in vaccination for labour market recovery, it also looks at vaccine roll-out as an additional COVID-19 containment measure, with 2021 as the main roll-out period. The results indicate very different responses to the three lockdowns, with a decline in job-posting activity of between 47 and 50% during the first lockdown and of between 29 and 31% during the second; but an increase of 23% to 28% during the last lockdown. Moreover, responses to the first lockdown were sluggish, with a slow decline at the beginning and a very slow recovery after it was lifted; but over subsequent lockdowns the responses were more rapid and more symmetrical. Responses to the various events differed by occupation and industry: the strongest responses were to be observed in the highly skilled and more-teleworkable occupations of technicians, and managers and professionals, who were badly affected during the first lockdown; the leisure and hospitality industry, which was the hardest hit on account of the mandatory closures and the widespread travel restrictions and bans, and which recovered only very slowly; and the IT, internet and telecommunications industry, where posting activity developed in a direction opposite to that seen in the other industries. Finally, there is little robust evidence of a differentiated effect of vaccinations during lockdowns, suggesting that vaccination roll-out did not have an additional demand-generating effect, over and above the lockdowns.

Spatiotemporal analysis of tropical vegetation ecosystems and their responses to multifaceted droughts in Mainland Southeast Asia using satellite-based time series

ABSTRACT Drought ranks among the costliest of all climate-related phenomena and manifests in various forms, posing significant challenges in understanding its influence on agriculture and natural ecosystems. Mainland Southeast Asia (MSEA), a significant region of tropical agriculture and vegetation ecosystems, has become increasingly susceptible to drought hazards. In this study, we characterized and assessed vegetation dynamics and their drought impacts using correlation analysis and explainable machine learning methods under different vegetation types and elevation zones during the dry growing seasons from 2000 to 2022. Specifically, we characterized the vegetation dynamics and their trend in space and time. Next, we assessed vegetation-drought responses in consideration of meteorological, hydrological, and agricultural droughts under different land cover types and elevation characteristics. Lastly, we used an explainable machine learning method to quantify the drivers and impacts of multifaceted droughts on natural and undisturbed vegetation ecosystems. Our findings revealed that nearly 70% of the MSEA region experienced a greening trend despite large areas of vegetative damage during the drought years. Vietnam witnessed increasing vegetation condition in most observed years while the declining trend was mainly found in Cambodia and southern Laos. Vegetation-drought responses showed that tropical vegetation had a high sensitivity to drought conditions, and stronger responses were observed in rainfed crop, mixed forest, and deciduous forest at lower altitude areas. In natural and undisturbed ecosystems, short-term meteorological and agricultural drought disturbances accounted for nearly 93% of variations in tropical vegetation. Among the different examined drought indices, the 3-month Standardized Precipitation Evapotranspiration (SPEI-3) and Temperature Condition Index (TCI) were identified as the factors having the largest influence, together explaining about 55% of the observed natural undisturbed vegetation variations. These findings deepen our understanding of tropical vegetation-drought responses and the underlying drivers of natural and undisturbed ecosystems. Such insights could provide valuable information to assist national and local governments in the MSEA region in developing effective drought management and adaptation programs to safeguard tropical agricultural production and natural ecosystems amidst growing climate challenges.

A microglia clonal inflammatory disorder in Alzheimer's Disease.

Somatic genetic heterogeneity resulting from post-zygotic DNA mutations is widespread in human tissues and can cause diseases, however few studies have investigated its role in neurodegenerative processes such as Alzheimer's Disease (AD). Here we report the selective enrichment of microglia clones carrying pathogenic variants, that are not present in neuronal, glia/stromal cells, or blood, from patients with AD in comparison to age-matched controls. Notably, microglia-specific AD-associated variants preferentially target the MAPK pathway, including recurrent CBL ring-domain mutations. These variants activate ERK and drive a microglia transcriptional program characterized by a strong neuro-inflammatory response, both in vitro and in patients. Although the natural history of AD-associated microglial clones is difficult to establish in human, microglial expression of a MAPK pathway activating variant was previously shown to cause neurodegeneration in mice, suggesting that AD-associated neuroinflammatory microglial clones may contribute to the neurodegenerative process in patients.

AB073. Electrocorticography high-gamma dynamics during intraoperative hand movement mapping.

Intraoperative functional mapping for glioma resection often necessitates awake craniotomies, requiring active patient participation. This procedure presents challenges for both the surgical team and the patient. Thus, minimizing mapping time becomes crucial. Passive mapping utilizing electrocorticography (ECoG) presents a promising approach to reduce intraoperative mapping efforts via direct electrical stimulation. This study aims to identify an efficient mapping protocol for hand movement by optimizing mapping duration and localization accuracy. Three glioma patients (two males, one female) underwent awake craniotomy for tumor resection at Asahikawa Medical University Hospital and Kindai University in Osaka. Patients were maintained at a bispectral index (BIS) level above 90 to ensure wakefulness during mapping. Data were collected using a DC-coupled g.HIamp biosignal amplifier, digitized with 24-bit resolution at a minimum sampling rate of 1,200 Hz. Each session comprised ten runs, each lasting 250 seconds, consisting of a 12-second rest phase (baseline) followed by a 12-second grasping period containing ten grasping movements. High-gamma activity (HGA, 60-170 Hz) was recorded from ECoG locations on the pre- and postcentral gyrus. Locations exhibiting significant grasping-related HGA, with stronger responses during early trials within a run, were classified as "attenuated". Among 37 electrodes on the sensorimotor cortex, 16 exhibited significant HGA during grasping. Three locations demonstrated significant attenuation after three runs, with one location showing attenuation after the first three trials within a run. The observed attenuation effect of short-term repeated movements during intraoperative monitoring is relatively modest initially. However, as the number of repeated grasping blocks increases, the number of attenuated locations also rises. Consequently, minimizing overall mapping time, rather than reducing the number of tasks per block, is paramount. For statistical analysis, a minimum of 20 grasping trials (two runs of ten movements) or 48 seconds of motor mapping is recommended. Alternatively, a mapping protocol involving a third run or 30 grasping trials (72 seconds) may enhance data robustness. These preliminary findings, though based on a limited patient cohort, warrant confirmation and further investigation, particularly in epilepsy patients.

Long-Term Safety and Efficacy of Focused Ultrasound Capsulotomy for Obsessive-Compulsive Disorder and Major Depressive Disorder

BackgroundMagnetic resonance–guided focused ultrasound (MRgFUS) trials targeting the anterior limb of the internal capsule have shown promising results. We evaluated the long-term safety and efficacy of MRgFUS capsulotomy in patients with obsessive-compulsive disorder (OCD) and major depressive disorder (MDD). MethodsThis phase 1, single-center, open-label study recruited patients with treatment-resistant OCD and MDD. Outcomes were measured 6 months, 12 months, and 18 to 24 months (long term) after MRgFUS capsulotomy. Neuropsychological testing and neuroimaging were conducted at baseline and 12 months postoperatively. The primary outcome was safety. The secondary outcome was clinical response, defined for OCD as a ≥35% improvement in Yale-Brown Obsessive Compulsive Scale scores and for MDD as a ≥50% reduction in Hamilton Depression Rating Scale scores compared with baseline. ResultsNo serious adverse effects were registered. In patients with OCD (n= 15), baseline Yale-Brown Obsessive Compulsive Scale scores (31.9 ± 1.2) were significantly reduced by 23% (p = .01) at 6 months and 35% (p < .0001) at 12 months. In patients with MDD (n = 12), a 26% and 25% nonsignificant reduction in Hamilton Depression Rating Scale scores (baseline 24.3 ± 1.2) was observed at 6 months and 12 months, respectively. Neuropsychological testing revealed no negative effects of capsulotomy. In the OCD and MDD cohorts, we found a correlation between clinical outcome and lesion laterality, with more medial left–placed lesions (OCD, p = .08) and more lateral right–placed lesions (MDD, p < .05) being respectively associated with a stronger response. In the MDD cohort, more ventral tracts appeared to be associated with a poorer response. ConclusionsMRgFUS capsulotomy is safe in patients with OCD and MDD and particularly effective in the former population.

D-π-A type fluorescent dyes: Effect of π-bridge units on optical and G4 DNA binding properties

Fluorescent solvatochromic dyes that are sensitive to the nature of local microenvironmental, have been explored as probes in applications ranging from the imaging biomolecules to understanding of basic biomolecule functions. To expand the scope of fluorescent solvatochromic dyes for G-quadruplex (G4) DNA structures, and to illustrate the relationship between structure and properties, three newly designed D-π-A type fluorescent dyes were synthesized by introducing diarylimidazole to carbazole skeleton linked to benzene, furan or thiophene π-conjugated bridge and connected with pyridinium acceptor, respectively. Their structural characteristics, optical properties, and G4 DNA binding properties were discussed in detail. In general, the incorporation of furan and thiophene as π-conjugated bridges leads the better conjugation and molecular coplanarity with more efficient intramolecular charge transfer (ICT) effect compared with benzene bridge. The fluorescence intensities induced upon interaction were found that TP-6 with thiophene π-conjugated bridge had the strongest response toward G4 DNAs. In addition, the application of this dye as a fluorescent agent for living cell imaging was also demonstrated.

Coxsackievirus B infection invokes unique cell-type specific responses in primary human pancreatic islets.

Coxsackievirus B (CVB) infection has long been considered an environmental factor precipitating Type 1 diabetes (T1D), an autoimmune disease marked by loss of insulin-producing β cells within pancreatic islets. Previous studies have shown CVB infection negatively impacts islet function and viability but do not report on how virus infection individually affects the multiple cell types present in human primary islets. Therefore, we hypothesized that the various islet cell populations have unique transcriptional responses to CVB infection. Here, we performed single-cell RNA sequencing on human cadaveric islets treated with either CVB or poly(I:C), a viral mimic, for 24 and 48 hours. Our global analysis reveals CVB differentially induces dynamic transcriptional changes associated with multiple cell processes and functions over time whereas poly(I:C) promotes an immune response that progressively increases with treatment duration. At the single-cell resolution, we find CVB infects all islet cell types at similar rates yet induces unique cell-type specific transcriptional responses with β, α, and ductal cells having the strongest response. Sequencing and functional data suggest that CVB negatively impacts mitochondrial respiration and morphology in distinct ways in β and α cells, while also promoting the generation of reactive oxygen species. We also observe an increase in the expression of the long-noncoding RNA MIR7-3HG in β cells with high viral titers and reveal its knockdown reduces gene expression of viral proteins as well as apoptosis in stem cell-derived islets. Together, these findings demonstrate a cell-specific transcriptional, temporal, and functional response to CVB infection and provide new insights into the relationship between CVB infection and T1D.

How do the gold intra-day returns and volatility react to monetary policy shocks?

In this paper, we use high frequency data to obtain novel asymmetry results in the short-term response of gold to monetary policy shocks. The gold returns and volatility 5 min after the shock are found to be more sensitive to looser than tighter FOMC rate announcement changes. This is explained by the increased appeal of gold during uncertainties and as a safe haven following negative monetary shocks. The rally in gold prices is construed by the market as an increase in the demand for safe haven assets, and hence, a stronger response in gold returns and volatility ensues. Moreover, we find that the gold price adjustment and its volatility adjustment continue for longer than five minutes after the FOMC shock. This suggests potential short-term inefficiencies in the gold market concerning the short-term rates.

Spaceflight causes strain dependent gene expression changes associated with lipid and extracellular matrix dysregulation in the mouse kidney in vivo.

To explore new worlds we must ensure humans can survive and thrive in the space environment. Incidence of kidney stones in astronauts is a major risk factor associated with long term missions, caused by increased blood calcium levels due to bone demineralisation triggered by microgravity and space radiation. Transcriptomic changes have been observed in other tissues during spaceflight, including the kidney. We analysed kidney transcriptome patterns in two different strains of mice flown on the International Space Station, C57BL/6J and BALB/c. Here we show a link between spaceflight and transcriptome patterns associated with dysregulation of lipid and extracellular matrix metabolism and altered transforming growth factor-beta signalling. A stronger response was seen in C57BL/6J mice than BALB/c. Genetic differences in hyaluronan metabolism between strains may confer protection against extracellular matrix remodelling through downregulation of epithelial-mesenchymal transition. We intend for our findings to contribute to development of new countermeasures against kidney disease in astronauts and people here on Earth.

Patterns of Diversity and Humoral Immunogenicity for HIV-1 Antisense Protein (ASP).

HIV-1 has an antisense gene overlapping env that encodes the ASP protein. ASP functions are still unknown, but it has been associated with gp120 in the viral envelope and membrane of infected cells, making it a potential target for immune response. Despite this, immune response patterns against ASP are poorly described and can be influenced by the high genetic variability of the env gene. To explore this, we analyzed 100k HIV-1 ASP sequences from the Los Alamos HIV sequence database using phylogenetic, Shannon entropy (Hs), and logo tools to study ASP variability in worldwide and Brazilian sequences from the most prevalent HIV-1 subtypes in Brazil (B, C, and F1). Data obtained in silico guided the design and synthesis of 15-mer overlapping peptides through spot synthesis on cellulose membranes. Peptide arrays were screened to assess IgG and IgM responses in pooled plasma samples from HIV controllers and individuals with acute or recent HIV infection. Excluding regions with low alignment accuracy, several sites with higher variability (Hs > 1.5) were identified among the datasets (25 for worldwide sequences, 20 for Brazilian sequences). Among sites with Hs < 1.5, sequence logos allowed the identification of 23 other sites with subtype-specific signatures. Altogether, amino acid variations with frequencies > 20% in the 48 variable sites identified were included in 92 peptides, divided into 15 sets, representing near full-length ASP. During the immune screening, the strongest responses were observed in three sets, one in the middle and one at the C-terminus of the protein. While some sets presented variations potentially associated with epitope displacement between IgG and IgM targets and subtype-specific signatures appeared to impact the level of response for some peptides, signals of cross-reactivity were observed for some sets despite the presence of B/C/F1 signatures. Our data provides a map of ASP regions preferentially targeted by IgG and IgM responses. Despite B/C/F1 subtype signatures in ASP, the amino acid variation in some areas preferentially targeted by IgM and IgG did not negatively impact the response against regions with higher immunogenicity.

Transcription Factor Condensates Mediate Clustering of MET Regulon and Enhancement in Gene Expression.

Some transcription factors (TFs) can form liquid-liquid phase separated (LLPS) condensates. However, the functions of these TF condensates in 3D genome organization and gene regulation remain elusive. In response to methionine (met) starvation, budding yeast TF Met4 and a few co-activators, including Met32, induce a set of genes involved in met biosynthesis. Here, we show that the endogenous Met4 and Met32 form co-localized puncta-like structures in yeast nuclei upon met depletion. Recombinant Met4 and Met32 form mixed droplets with LLPS properties in vitro. In relation to chromatin, Met4 puncta co-localize with target genes, and at least a subset of these target genes is clustered in 3D in a Met4-dependent manner. A MET3pr-GFP reporter inserted near several native Met4 binding sites becomes co-localized with Met4 puncta and displays enhanced transcriptional activity. A Met4 variant with a partial truncation of an intrinsically disordered region (IDR) shows less puncta formation, and this mutant selectively reduces the reporter activity near Met4 binding sites to the basal level. Overall, these results support a model where Met4 and co-activators form condensates to bring multiple target genes into a vicinity with higher local TF concentrations, which facilitates a strong response to methionine depletion.

Strain variation in the Candida albicans iron limitation response.

Iron acquisition is critical for pathogens to proliferate during invasive infection, and the human fungal pathogen Candida albicans is no exception. The iron regulatory network, established in reference strain SC5314 and derivatives, includes the central player Sef1, a transcription factor that activates iron acquisition genes in response to iron limitation. Here, we explored potential variation in this network among five diverse C. albicans strains through mutant analysis, Nanostring gene expression profiling, and, for two strains, RNA-Seq. Our findings highlight four features that may inform future studies of natural variation and iron acquisition in this species. (i) Conformity: In all strains, major iron acquisition genes are upregulated during iron limitation, and a sef1Δ/Δ mutation impairs that response and growth during iron limitation. (ii) Response variation: Some aspects of the iron limitation response vary among strains, notably the activation of hypha-associated genes. As this gene set is tied to tissue damage and virulence, variation may impact the progression of infection. (iii) Genotype-phenotype variation: The impact of a sef1Δ/Δ mutation on cell wall integrity varies, and for the two strains examined the phenotype correlated with sef1Δ/Δ impact on several cell wall integrity genes. (iv) Phenotype discovery: DNA repair genes were induced modestly by iron limitation in sef1Δ/Δ mutants, with fold changes we would usually ignore. However, the response occurred in both strains tested and was reminiscent of a much stronger response described in Cryptococcus neoformans, a suggestion that it may have biological meaning. In fact, we observed that the iron limitation of a sef1Δ/Δ mutant caused recessive phenotypes to emerge at two heterozygous loci. Overall, our results show that a network that is critical for pathogen proliferation presents variation outside of its core functions.IMPORTANCEA key virulence factor of Candida albicans is the ability to maintain iron homeostasis in the host where iron is scarce. We focused on a central iron regulator, SEF1. We found that iron regulator Sef1 is required for growth, cell wall integrity, and genome integrity during iron limitation. The novel aspect of this work is the characterization of strain variation in a circuit that is required for survival in the host and the connection of iron acquisition to genome integrity in C. albicans.

Effect of AZO seed layers on the ultraviolet photoresponse of Ag/ZnO NRs Schottky junctions

Al-doped ZnO (AZO) thin films with different layers were prepared by sol-gel method. The SEM, XRD and AFM for three layers thin films demonstrates high crystal quality and low roughness. ZnO nanorods arrays (NRs) with different AZO seed layers were fabricated using hydrothermal process, and the effect of AZO seed layers on the structural, optical, and electrical characteristics was investigated. When there are three AZO seed layers present, ZnO NRs exhibit fewer surface states, smaller interface charge transfer resistance (Rce = 6.1 × 103Ωand Rct = 6.6 × 106Ω), longer carrier lifetimes (τe = 4.0 ms), higher carrier concentration (ND = 4.73 × 1019 cm−3), and narrower depletion region width W = 3.1 nm. Under weak UV light 381 nm (5.68 mW/cm2) at a bias −0.5 V, Ag/ZnO NRs Schottky devices with three AZO seed layers display a comparatively strong responsivity 34.64 mA/W. Appropriate AZO seed layers are favorable for highly efficient ZnO NRs-based photoelectric conversion devices.