Distinct Functions In Response Research Articles

Functional and regulatory diversity of homeobox-leucine zipper transcription factors BnaHB6 under dehydration and salt stress in Brassica napus L.

The plant-specific homeodomain-leucine zipper I subfamily is involved in the regulation of various biological processes, particularly growth, development and stress response. In the present study, we characterized four BnaHB6 homologues from Brassica napus. All BnaHB6 proteins have transcriptional activation activity. Structural and functional data indicate the complex role of BnaHB6 genes in regulating biological processes, with some functions conserved and others diverged. Transcriptional analyzes revealed that they are induced in a similar manner in different tissues but show different expression patterns in response to stress and circadian rhythm. Only the BnaA09HB6 and BnaC08HB6 genes are expressed under dehydration and salt stress, and in darkness. The partial transcriptional overlap of BnaHB6s with the evolutionarily related genes BnaHB5 and BnaHB16 was also observed. Transgenic Arabidopsis thaliana plants expressing a single proBnaHB6::GUS partially confirmed the expression results. Bioinformatic analysis allowed the identification of TF-binding sites in the BnaHB6 promoters that may control their expression under stress and circadian rhythm. ChIP-qPCR analysis revealed that BnaA09HB6 and BnaC08HB6 bind directly to the promoters of the target genes BnaABF4 and BnaDREB2A. Comparison of their expression patterns in the WT plants and the bnac08hb6 mutant showed that BnaC08HB6 positively regulates the expression of the BnaABF4 and BnaDREB2A genes under dehydration and salt stress. We conclude that four BnaHB6 homologues have distinct functions in response to stress despite high sequence similarity, possibly indicating different binding preferences with BnaABF4 and BnaDREB2A. We hypothesize that BnaC08HB6 and BnaA09HB6 function in a complex regulatory network under stress.

The Receptor Kinases DRUS1 and DRUS2 Behave Distinctly in Osmotic Stress Tolerance by Modulating the Root System Architecture via Auxin Signaling.

Receptor kinases DRUS1 (Dwarf and Runtish Spikelet1) and DRUS2 are orthologues of the renowned Arabidopsis thaliana gene FERONIA, which play redundant roles in rice growth and development. Whether the two duplicated genes perform distinct functions in response to environmental stress is largely unknown. Here, we found that osmotic stress (OS) and ABA increased DRUS1 expression while decreasing DRUS2. When subjected to osmotic stress, the increased DRUS1 in drus2 mutants suppresses the OsIAA repressors, resulting in a robust root system with an increased number of adventitious and lateral roots as well as elongated primary, adventitious, and lateral roots, conferring OS tolerance. In contrast, the decreased DRUS2 in drus1-1 mutants are not sufficient to suppress OsIAA repressors, leading to a feeble root system with fewer adventitious and lateral roots and hindering seminal root growth, rendering OS intolerance. All these findings offer valuable insights into the biological significance of the duplication of two homologous genes in rice, wherein, if one is impaired, the other one is able to continue auxin-signaling-mediated root growth and development to favor resilience to environmental stress, such as water shortage.

Site-specific encoding of photoactivity and photoreactivity into antibody fragments

Design of biomolecules that perform two or more distinct functions in response to light remains challenging. Here, we have introduced concurrent photoactivity and photoreactivity into an epidermal growth factor receptor (EGFR)-targeting antibody fragment, 7D12. This was achieved by site-specific incorporation of photocaged tyrosine (pcY) for photoactivity and p-benzoyl-ʟ-phenylalanine (Bpa) for photoreactivity into 7D12. We identified a position for installing Bpa in 7D12 that has minimal effect on 7D12–EGFR binding affinity in the absence of light. Upon exposure to 365-nm light, this Bpa-containing 7D12 mutant forms a covalent bond with EGFR in an antigen-specific manner. We then developed a method for site-specific incorporation of pcY and Bpa at two distinct sites in 7D12. Finally, we demonstrated that in the absence of light, this pcY- and Bpa-containing mutant of 7D12 does not bind to EGFR, but irradiation with 365-nm light activates (1) specific binding and (2) covalent bond formation with EGFR.

Environmental Cues Contribute to Dynamic Plasma Membrane Organization of Nanodomains Containing Flotillin-1 and Hypersensitive Induced Reaction-1 Proteins in Arabidopsis thaliana.

Plasma membranes are heterogeneous and contain multiple functional nanodomains. Although several signaling proteins have been shown to function by moving into or out of nanodomains, little is known regarding the effects of environmental cues on nanodomain organization. In this study, we investigated the heterogeneity and organization of distinct nanodomains, including those containing Arabidopsis thaliana flotillin-1 (AtFlot1) and hypersensitive induced reaction-1 proteins (AtHIR1), in response to biotic and abiotic stress. Variable-angle total internal reflection fluorescence microscopy coupled with single-particle tracking (SPT) revealed that AtFlot1 and AtHIR1 exhibit different lateral dynamics and inhabit different types of nanodomains. Furthermore, via SPT and fluorescence correlation spectroscopy, we observed lower density and intensity of AtFlot1 fluorescence in the plasma membrane after biotic stress. In contrast, the density and intensity of signal indicating AtHIR1 markedly increased in response to biotic stress. In response to abiotic stress, the density and intensity of both AtFlot1 and AtHIR1 signals decreased significantly. Importantly, SPT coupled with fluorescence recovery after photobleaching revealed that biotic and abiotic stress can regulate the dynamics of AtFlot1; however, only the abiotic stress can regulate AtHIR1 dynamics. Taken together, these findings suggest that a plethora of highly distinct nanodomains coexist in the plasma membrane (PM) and that different nanodomains may perform distinct functions in response to biotic and abiotic stresses. These phenomena may be explained by the spatial clustering of plasma membrane proteins with their associated signaling components within dedicated PM nanodomains.

Functional characterization of late embryogenesis abundant genes and promoters in pearl millet (Pennisetum glaucum L.) for abiotic stress tolerance.

Late embryogenesis abundant (LEA) genes display distinct functions in response to abiotic stresses in plants. In pearl millet (Pennisetum glaucum L.), a total of 21 PgLEA genes were identified and classified into six groups including LEA1, LEA2, LEA3, LEA5, LEA7, and dehydrins (DHN). Open reading frames (ORFs) of PgLEAs range from 291 bp (PgLEA1-1) to 945 bp (PgLEA2-11) and distributed randomly among the seven chromosomes. Phylogenetic analysis revealed that all PgLEA proteins are closely related to sorghum LEA proteins. The PgLEAs were found to be expressed differentially under high progressive vapor pressure deficit (VPD), PgLEA7 was significantly expressed under high VPD and was selected for functional validation. In silico analysis of the PgLEA promoter regions revealed abiotic stress-specific cis-acting elements such as ABRE, CCAAT, MYBS, and LTRE. Based on the type of motifs, PgLEAPC promoter (758 bp), its deletion 1 (PgLpd1, 349 bp) and deletion 2 (PgLpd2, 125 bp) were cloned into the plant expression vector pMDC164 having the promoter-less uidA gene. All the three plant expression vectors were introduced into tobacco through Agrobacterium tumefaciens-mediated transformation to obtain T1 and T2 generations of transgenic plants. Based on expression of the uidA gene, tissue-specific expression was observed in mature stems, roots and seedlings of PgLEAPC and PgLpd1 carrying transgenics only. While the transgenic PgLEAPC plants displayed significantly higher uidA expression in the stem and root tissues under salt, drought, heat, and cold stresses, very low or no expression was observed in PgLpd1 and PgLpd2 transgenics under the tested stress conditions. The results of this study indicate that the complete promoter of PgLEAPC plays a role in developing abiotic stress tolerance in plants.

A Tunable Palette of Molecular Rotors Allows Multicolor, Ratiometric Fluorescence Imaging and Direct Mapping of Mitochondrial Heterogeneity.

Environment-sensitive molecular probes offer the potential for a comprehensive mapping of the complex cellular milieu. We present here a radically new strategy of multiplexing highly sensitive, spectrally tuned fluorescent dyes for sensing cellular microenvironment. To achieve this multicolor, ratiometric cellular imaging, we first developed a series of highly sensitive, tunable molecular rotors for mitochondrial imaging, with emission wavelengths spanning the visible spectrum. These fluorogenic merocyanine dyes are all sensitive to solvent viscosity despite distinctive photophysical features. Our results show that merocyanine dyes can show a rotor-like behavior despite significant changes to the conventional donor-acceptor or push-pull scaffolds, thereby revealing conserved features of rotor dye chemistry. Developing closely related but spectrally separated dyes that have distinct response functions allows us to do ″two-color, two-dye″ imaging of the mitochondrial microenvironment. Our results with multidye, combinatorial imaging provide a direct visualization of the intrinsic heterogeneity of the mitochondrial microenvironment. The overall mitochondrial microenvironment (including contributions from local membrane order) as reported through two-color fluorescence ″ratio″ changes of multiplexed rotor dyes shows dynamic heterogeneity with distinct spatiotemporal signatures that evolve over time and respond to chemical perturbations. Our results offer a powerful illustration of how multiplexed dye imaging allows the quantitative imaging of mitochondrial membrane order and cellular microenvironment.

A Heterogeneous Spiking Neural Network for Unsupervised Learning of Spatiotemporal Patterns.

This paper introduces a heterogeneous spiking neural network (H-SNN) as a novel, feedforward SNN structure capable of learning complex spatiotemporal patterns with spike-timing-dependent plasticity (STDP) based unsupervised training. Within H-SNN, hierarchical spatial and temporal patterns are constructed with convolution connections and memory pathways containing spiking neurons with different dynamics. We demonstrate analytically the formation of long and short term memory in H-SNN and distinct response functions of memory pathways. In simulation, the network is tested on visual input of moving objects to simultaneously predict for object class and motion dynamics. Results show that H-SNN achieves prediction accuracy on similar or higher level than supervised deep neural networks (DNN). Compared to SNN trained with back-propagation, H-SNN effectively utilizes STDP to learn spatiotemporal patterns that have better generalizability to unknown motion and/or object classes encountered during inference. In addition, the improved performance is achieved with 6x fewer parameters than complex DNNs, showing H-SNN as an efficient approach for applications with constrained computation resources.

Temperature-dependent upconversion luminescence in ferroelectric 1.5%Pr/3%Yb:0.75Pb(Mg1/3Nb2/3)O3–0.25PbTiO3 transparent ceramics for non-contact thermometry and optical heating

Non-contact optical thermometry based upon fluorescence intensity ratio (FIR) has attracted much attention because of its excellent accuracy and sensitivity. Recently we reported the upconversion luminescence in Pr3+/Yb3+ co-doped 0.75Pb(Mg1/3Nb2/3)O3–0.25PbTiO3 transparent ceramics [Z. Lv et al., Ceramics International 45 (2019) 10924–10929]. In this article we study the temperature dependence of upconversion emissions from the 1.5%Pr/3%Yb:0.75Pb(Mg1/3Nb2/3)O3–0.25PbTiO3 transparent ceramics. The FIR between the 1D2-3H4 and 3P0–3H4 emissions fits a thermally coupled-levels-like equation, and exhibits the maximum relative sensitivity of 1.03% K−1 at the temperature 320 K. Meanwhile, the FIRs of IRed/IGreen, IRed/IBlue and IRed/IBG show linear responses versus temperature and illustrate the high constant sensitivities of 1.09%–2.9% K−1, but in a narrow temperature range of 140–240 K. The multiple temperature-sensing performances offer us chances to select distinct response functions on the basis of the practical demands. In addition, laser induced heating was observed in the transparent ceramics. The generated temperature in the ceramics can be accurately monitored and regulated from 329 to 377 K by changing the excitation power from 1.58 to 8.61 W/cm2. The high heating efficiency of ~6.83 K cm2/W makes the transparent ceramics suitable for optical heater. The transparent ceramics exhibit excellent piezoelectric and ferroelectric performances, and thus they are promising candidates for multifunctional optical-electro devices besides non-contact thermometer and optical heater.

Macrophage Polarization Induced by Probiotic Bacteria: a Concise Review.

Macrophages display remarkable plasticity and can possess distinct functions in response to different environmental stimuli. Classically activated macrophages (M1 macrophages) are pro-inflammatory and have a critical role in host defense against infection, while alternatively activated macrophages (M2 macrophages) suppress inflammatory responses and associated with wound repair. Probiotic bacteria are reported to have a beneficial effect on the host immune status through their ability to modulate the macrophage polarization. Some probiotic strains are reported to activate macrophages to M1 phenotype to kill intracellular pathogens, while some other probiotics can induce M2 macrophages to exert the anti-inflammatory effect. Thus, this review will focus on the immunomodulatory role of probiotics in macrophage polarization and summarize the mode of action of probiotics in regulating macrophage plasticity. The detailed understanding of the immunomodulatory signaling effects of probiotic bacteria will broaden our understanding of how probiotics may regulate the immune system and find their therapeutic potentials for inflammatory diseases.

Genome-wide identification and expression analysis of HSP90 gene family in Nicotiana tabacum

BackgroundHeat shock proteins 90 (HSP90s) are a highly conserved protein family of cellular chaperones widely found in plants; they play a fundamental role in response to biotic and abiotic stresses. The genome-wide analysis of HSP90 gene family has been completed for some species; however, it has been rarely reported for the tobacco HSP90 genes.ResultsIn this study, we systematically conducted genome-wide identification and expression analysis of the tobacco HSP90 gene family, including gene structures, evolutionary relationships, chromosomal locations, conserved domains, and expression patterns. Twenty-one NtHSP90s were identified and classified into eleven categories (NtHSP90–1 to NtHSP90–11) based on phylogenetic analysis. The conserved structures and motifs of NtHSP90 proteins in the same subfamily were highly consistent. Most NtHSP90 proteins contained the ATPase domain, which was closely related to conserved motif 2. Motif 5 was a low complexity sequence and had the function of signal peptide. At least 6 pairs of NtHSP90 genes underwent gene duplication, which arose from segment duplication and tandem duplication events. Phylogenetic analysis showed that most species expanded according to their own species-specific approach during the evolution of HSP90s. Dynamic expression analysis indicated that some NtHSP90 genes may play fundamental roles in regulation of abiotic stress response. The expression of NtHSP90–4, NtHSP90–5, and NtHSP90–9 were up-regulated, while NtHSP90–6, and NtHSP90–7 were not induced by ABA, drought, salt, cold and heat stresses. Among the five treatments, NtHSP90s were most strongly induced by heat stress, and weakly activated by ABA treatment. There was a similar response pattern of NtHSP90s under osmotic stress, or extreme temperature stress.ConclusionsThis is the first genome-wide analysis of Hsp90 in N. tabacum. These results indicate that each NtHSP90 member fulfilled distinct functions in response to various abiotic stresses.

Unique properties of PTEN-L contribute to neuroprotection in response to ischemic-like stress

Phosphatase and tensin homolog (PTEN) signalling might influence neuronal survival after brain ischemia. However, the influence of the less studied longer variant termed PTEN-L (or PTENα) has not been studied to date. Therefore, we examined the translational variant PTEN-L in the context of neuronal survival. We identified PTEN-L by proteomics in murine neuronal cultures and brain lysates and established a novel model to analyse PTEN or PTEN-L variants independently in vitro while avoiding overexpression. We found that PTEN-L, unlike PTEN, localises predominantly in the cytosol and translocates to the nucleus 10–20 minutes after glutamate stress. Genomic ablation of PTEN and PTEN-L increased neuronal susceptibility to oxygen-glucose deprivation. This effect was rescued by expression of either PTEN-L indicating that both PTEN isoforms might contribute to a neuroprotective response. However, in direct comparison, PTEN-L replaced neurons were protected against ischemic-like stress compared to neurons expressing PTEN. Neurons expressing strictly nuclear PTEN-L NLS showed increased vulnerability, indicating that nuclear PTEN-L alone is not sufficient in protecting against stress. We identified mutually exclusive binding partners of PTEN-L or PTEN in cytosolic or nuclear fractions, which were regulated after ischemic-like stress. GRB2-associated-binding protein 2, which is known to interact with phosphoinositol-3-kinase, was enriched specifically with PTEN-L in the cytosol in proximity to the plasma membrane and their interaction was lost after glutamate exposure. The present study revealed that PTEN and PTEN-L have distinct functions in response to stress and might be involved in different mechanisms of neuroprotection.

Genome-wide identification and characterization of Hsp70 gene family in Nicotiana tabacum.

Heat shock proteins 70 (Hsp70) constitute a highly conserved protein family of cellular chaperones widely distributed in plants, where they play a fundamental role in response to biotic and abiotic stress. Until now, genome-wide analyses of the Hsp70 gene family have been conducted for some species. However, reports about Hsp70 genes in Nicotiana tabacum are scarce. In this study, we systematically conducted genome-wide identification and expression analysis of the Hsp70 gene family in tobacco, including gene structure, classification, evolutionary relationships, promoters, and transcript levels in response to abiotic stress treatments. In all, 61 Hsp70 members were identified and classified into six groups that were mapped onto 18 chromosomes, where most were distributed on both ends of the chromosome. The conserved structures and motifs of NtHsp70 proteins in the same subfamily were highly consistent. At least 15 pairs of NtHsp70 genes underwent gene duplication by segment and tandem duplications. Most NtHsp70 proteins contained N-terminal hexokinase conserved motifs. Phylogenetic analysis showed that most species expanded according to their own species-specific approach during the evolution of Hsp70s. Tissue-specific expression analysis indicated that all NtHsp70 genes were involved in at least one or more abiotic stress responses, highlighting the wide participation of NtHsp70 genes in environmental adaptation. This is the first genome-wide analysis of Hsp70 in N. tabacum. These results indicate that each NtHsp70 member fulfilled distinct functions in response to various abiotic stresses.

T follicular helper cell programming by cytokine-mediated events.

CD4+ T cells, or T helper cells, are critical mediators and coordinators of adaptive immunity. Unique effector T helper cell populations have been identified that perform distinct functions in response to pathogenic infection. The T follicular helper (Tfh) cells are one such subset, which has been identified as the primary T-cell population responsible for interacting with B cells to promote effective antibody-mediated immune responses. Since their initial description at the turn of the century, and subsequent classification as a distinct T helper cell subset, there has been substantial interest in elucidating the regulatory mechanisms that govern Tfh cell formation. The collective insight from this body of work has demonstrated that Tfh cell differentiation is a complex and multistage process regulated by a litany of cell-intrinsic and cell-extrinsic factors. As with the development of the other recognized T helper cell subsets, specific cytokines exercise prominent roles in both the positive and negative regulation of Tfh cell development. However, the exact composition of, and stage-specific requirements for, these environmental factors in the governance of Tfh cell differentiation remain incompletely understood. In this review, we summarize what is known regarding the role of cytokines in both the promotion and inhibition of Tfh cell differentiation and function.

Distinct sensitivities to phosphate deprivation suggest that RGF peptides play disparate roles in Arabidopsis thaliana root development.

Growing agricultural demands in the face of impending inorganic phosphate (Pi) shortages underscore a need for a better understanding of plant development under conditions of Pi deprivation. Pi is an essential nutrient that is a major component of fertilizer. Plants have evolved strategies to improve the acquisition of this nutrient by altering root development under shortage conditions. We show that signaling peptides thought to act redundantly in Arabidopsis thaliana development have distinct functions in response to Pi deprivation. Using microscopy and confocal imaging, roots were analyzed for growth rate and cellular composition. Using expression microarrays, genes influencing development in response to phosphate deprivation were identified. ROOT GROWTH FACTOR1 (RGF1) and RGF2 influenced different aspects of root development under conditions of Pi deprivation. We found that RGF2 influenced the longitudinal growth rate in the primary root in response to Pi deprivation, whereas RGF1 affected circumferential cell number in the root meristem. These data suggest that the mechanisms controlling adaptive development can depend on disparate functions of genes thought to act redundantly, thus elucidating new functions for important developmental regulators.

Differential Regulation of the Heat Shock Factor 1 and DAF-16 by Neuronal nhl-1 in the Nematode C. elegans

In the nematode Caenorhabditis elegans, insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) reduction hyperactivates the transcription factors DAF-16 and heat shock factor 1 (HSF-1), creating long-lived, stress-resistant worms that are protected from proteotoxicity. How DAF-16 executes its distinct functions in response to IIS reduction is largely obscure. Here, we report that NHL-1, a member of the TRIM-NHL protein family, acts in chemosensory neurons to promote stress resistance in distal tissues by DAF-16 activation but is dispensable for the activation of HSF-1. The expression of nhl-1 is regulated by the IIS, defining a neuronal regulatory circuit that controls the organismal stress response. The knockdown of nhl-1 protects nematodes that express the Alzheimer-disease-associated Aβ peptide from proteotoxicity but has no effect on lifespan. Our findings indicate that DAF-16- and HSF-1-regulated heat-responsive mechanisms are differentially controlled by neurons and show that one neuronal protein can be involved in the activation of different stress responses in remote tissues.

Two closely related members of Arabidopsis 13‐lipoxygenases (13‐LOXs), LOX3 and LOX4, reveal distinct functions in response to plant‐parasitic nematode infection

The responses of two closely related members of Arabidopsis 13-lipoxygenases (13-LOXs), LOX3 and LOX4, to infection by the sedentary nematodes root-knot nematode (Meloidogyne javanica) and cyst nematode (Heterodera schachtii) were analysed in transgenic Arabidopsis seedlings. The tissue localization of LOX3 and LOX4 gene expression using β-glucuronidase (GUS) reporter gene constructs showed local induction of LOX3 expression when second-stage juveniles reached the vascular bundle and during the early stages of plant-nematode interaction through gall and syncytia formation. Thin sections of nematode-infested knots indicated LOX3 expression in mature giant cells, and high expression in neighbouring cells and those surrounding the female body. LOX4 promoter was also activated by nematode infection, although the GUS signal weakened as infection and disease progressed. Homozygous insertion mutants lacking LOX3 were less susceptible than wild-type plants to root-knot nematode infection, as reflected by a decrease in female counts. Conversely, deficiency in LOX4 function led to a marked increase in females and egg mass number and in the female to male ratio of M. javanica and H. schachtii, respectively. The susceptibility of lox4 mutants was accompanied by increased expression of allene oxide synthase, allene oxide cyclase and ethylene-responsive transcription factor 4, and the accumulation of jasmonic acid, measured in the roots of lox4 mutants. This response was not found in lox3 mutants. Taken together, our results reveal that LOX4 and LOX3 interfere differentially with distinct metabolic and signalling pathways, and that LOX4 plays a major role in controlling plant defence against nematode infection.

Contribution of directly connected and isolated impervious areas to urban drainage network hydrographs

Abstract. This paper addresses the mass balance error observed in runoff hydrographs in urban watersheds by introducing assumptions regarding the contribution of infiltrated rainfall from pervious areas and isolated impervious area (IIA) to the runoff hydrograph. Rainfall infiltrating into pervious areas has been assumed not to contribute to the runoff hydrograph until Hortonian excess rainfall occurs. However, mass balance analysis in an urban watershed indicates that rainfall infiltrated to pervious areas can contribute directly to the runoff hydrograph, thereby offering an explanation for the long hydrograph tail commonly observed in runoff from urban storm sewers. In this study, a hydrologic analysis based on the width function is introduced, with two types of width functions obtained from both pervious and impervious areas, respectively. The width function can be regarded as the direct interpretation of the network response. These two width functions are derived to obtain distinct response functions for directly connected impervious areas (DCIA), IIA, and pervious areas. The results show significant improvement in the estimation of runoff hydrographs and suggest the need to consider the flow contribution from pervious areas to the runoff hydrograph. It also implies that additional contribution from flow paths through joints and cracks in sewer pipes needs to be taken into account to improve the estimation of runoff hydrographs in urban catchments.

Characterization of Rice NADPH Oxidase Genes and Their Expression under Various Environmental Conditions

Plasma membrane NADPH oxidases (Noxs) are key producers of reactive oxygen species under both normal and stress conditions in plants. We demonstrate that at least eleven genes in the genome of rice (Oryza sativa L.) were predicted to encode Nox proteins, including nine genes (OsNox1–9) that encode typical Noxs and two that encode ancient Nox forms (ferric reduction oxidase 1 and 7, OsFRO1 and OsFRO7). Phylogenetic analysis divided the Noxs from nine plant species into six subfamilies, with rice Nox genes distributed among subfamilies I to V. Gene expression analysis using semi-quantitative RT-PCR and real-time qRT-PCR indicated that the expression of rice Nox genes depends on organs and environmental conditions. Exogenous calcium strongly stimulated the expression of OsNox3, OsNox5, OsNox7, and OsNox8, but depressed the expression of OsFRO1. Drought stress substantially upregulated the expression of OsNox1–3, OsNox5, OsNox9, and OsFRO1, but downregulated OsNox6. High temperature upregulated OsNox5–9, but significantly downregulated OsNox1–3 and OsFRO1. NaCl treatment increased the expression of OsNox2, OsNox8, OsFRO1, and OsFRO7, but decreased that of OsNox1, OsNox3, OsNox5, and OsNox6. These results suggest that the expression profiles of rice Nox genes have unique stress-response characteristics, reflecting their related but distinct functions in response to different environmental stresses.

Real‐time high‐resolution magnetic resonance tracking of macrophage subpopulations in a murine inflammation model: a pilot study with a commercially available cryogenic probe

Macrophages present different polarization states exhibiting distinct functions in response to environmental stimuli. However, the dynamic of their migration to sites of inflammation is not fully elucidated. Here we propose a real-time in vivo cell tracking approach, using high-resolution (HR)-MRI obtained with a commercially available cryogenic probe (Cryoprobe™), to monitor trafficking of differently polarized macrophages after systemic injection into mice. Murine bone marrow-derived mononuclear cells were differentiated ex vivo into nonpolarized M0, pro-inflammatory M1 and immunomodulator M2 macrophage subsets and labeled with citrate-coated anionic iron oxide nanoparticles (AMNP). These cells were subsequently intravenously injected to mice bearing calf muscle inflammation. Whole body migration dynamics of macrophage subsets was monitored by MRI at 4.7 T with a volume transmission/reception radiofrequency coil and macrophage infiltration to the inflamed paw was monitored with the cryogenic probe, allowing 3D spatial resolution of 50 µm with a scan time of only 10 min. Capture of AMNP was rapid and efficient regardless of macrophage polarization, with the highest uptake in M2 macrophages. Flow cytometry confirmed that macrophages preserved their polarization hallmarks after labeling. Migration kinetics of labeled cells differed from that of free AMNP. A preferential homing of M2-polarized macrophages to inflammation sites was observed. Our in vivo HR-MRI protocol highlights the extent of macrophage infiltration to the inflammation site. Coupled to whole body imaging, HR-MRI provides quantitative information on the time course of migration of ex vivo-polarized intravenously injected macrophages.

Specific leaf areas of the tank bromeliad Guzmania monostachia perform distinct functions in response to water shortage

Leaves comprise most of the vegetative body of tank bromeliads and are usually subjected to strong longitudinal gradients. For instance, while the leaf base is in contact with the water accumulated in the tank, the more light-exposed middle and upper leaf sections have no direct access to this water reservoir. Therefore, the present study attempted to investigate whether different leaf portions of Guzmania monostachia, a tank-forming C 3-CAM bromeliad, play distinct physiological roles in response to water shortage, which is a major abiotic constraint in the epiphytic habitat. Internal and external morphological features, relative water content, pigment composition and the degree of CAM expression were evaluated in basal, middle and apical leaf portions in order to allow the establishment of correlations between the structure and the functional importance of each leaf region. Results indicated that besides marked structural differences, a high level of functional specialization is also present along the leaves of this bromeliad. When the tank water was depleted, the abundant hydrenchyma of basal leaf portions was the main reservoir for maintaining a stable water status in the photosynthetic tissues of the apical region. In contrast, the CAM pathway was intensified specifically in the upper leaf section, which is in agreement with the presence of features more suitable for the occurrence of photosynthesis at this portion. Gas exchange data indicated that internal recycling of respiratory CO 2 accounted for virtually all nighttime acid accumulation, characterizing a typical CAM-idling pathway in the drought-exposed plants. Altogether, these data reveal a remarkable physiological complexity along the leaves of G. monostachia, which might be a key adaptation to the intermittent water supply of the epiphytic niche.